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Sample records for solar dynamics observatory

  1. Fe IX CALCULATIONS FOR THE SOLAR DYNAMICS OBSERVATORY

    International Nuclear Information System (INIS)

    Foster, Adam R.; Testa, Paola

    2011-01-01

    New calculations of the energy levels, radiative transition rates, and collisional excitation rates of Fe IX have been carried out using the Flexible Atomic Code, paying close attention to experimentally identified levels and extending existing calculations to higher energy levels. For lower levels, R-matrix collisional excitation rates from earlier work have been used. Significant emission is predicted by these calculations in the 5f-3d transitions, which will impact analysis of Solar Dynamics Observatory Atmospheric Imaging Assembly observations using the 94 A filter.

  2. Computer Vision for the Solar Dynamics Observatory (SDO)

    Science.gov (United States)

    Martens, P. C. H.; Attrill, G. D. R.; Davey, A. R.; Engell, A.; Farid, S.; Grigis, P. C.; Kasper, J.; Korreck, K.; Saar, S. H.; Savcheva, A.; Su, Y.; Testa, P.; Wills-Davey, M.; Bernasconi, P. N.; Raouafi, N.-E.; Delouille, V. A.; Hochedez, J. F.; Cirtain, J. W.; Deforest, C. E.; Angryk, R. A.; de Moortel, I.; Wiegelmann, T.; Georgoulis, M. K.; McAteer, R. T. J.; Timmons, R. P.

    2012-01-01

    In Fall 2008 NASA selected a large international consortium to produce a comprehensive automated feature-recognition system for the Solar Dynamics Observatory (SDO). The SDO data that we consider are all of the Atmospheric Imaging Assembly (AIA) images plus surface magnetic-field images from the Helioseismic and Magnetic Imager (HMI). We produce robust, very efficient, professionally coded software modules that can keep up with the SDO data stream and detect, trace, and analyze numerous phenomena, including flares, sigmoids, filaments, coronal dimmings, polarity inversion lines, sunspots, X-ray bright points, active regions, coronal holes, EIT waves, coronal mass ejections (CMEs), coronal oscillations, and jets. We also track the emergence and evolution of magnetic elements down to the smallest detectable features and will provide at least four full-disk, nonlinear, force-free magnetic field extrapolations per day. The detection of CMEs and filaments is accomplished with Solar and Heliospheric Observatory (SOHO)/ Large Angle and Spectrometric Coronagraph (LASCO) and ground-based Hα data, respectively. A completely new software element is a trainable feature-detection module based on a generalized image-classification algorithm. Such a trainable module can be used to find features that have not yet been discovered (as, for example, sigmoids were in the pre- Yohkoh era). Our codes will produce entries in the Heliophysics Events Knowledgebase (HEK) as well as produce complete catalogs for results that are too numerous for inclusion in the HEK, such as the X-ray bright-point metadata. This will permit users to locate data on individual events as well as carry out statistical studies on large numbers of events, using the interface provided by the Virtual Solar Observatory. The operations concept for our computer vision system is that the data will be analyzed in near real time as soon as they arrive at the SDO Joint Science Operations Center and have undergone basic

  3. Attitude Control System Design for the Solar Dynamics Observatory

    Science.gov (United States)

    Starin, Scott R.; Bourkland, Kristin L.; Kuo-Chia, Liu; Mason, Paul A. C.; Vess, Melissa F.; Andrews, Stephen F.; Morgenstern, Wendy M.

    2005-01-01

    The Solar Dynamics Observatory mission, part of the Living With a Star program, will place a geosynchronous satellite in orbit to observe the Sun and relay data to a dedicated ground station at all times. SDO remains Sun- pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system is a single-fault tolerant design. Its fully redundant attitude sensor complement includes 16 coarse Sun sensors, a digital Sun sensor, 3 two-axis inertial reference units, 2 star trackers, and 4 guide telescopes. Attitude actuation is performed using 4 reaction wheels and 8 thrusters, and a single main engine nominally provides velocity-change thrust. The attitude control software has five nominal control modes-3 wheel-based modes and 2 thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. The paper details the mode designs and their uses.

  4. Tuning the Solar Dynamics Observatory Onboard Kalman Filter

    Science.gov (United States)

    Halverson, Julie Kay; Harman, Rick; Carpenter, Russell; Poland, Devin

    2017-01-01

    The Solar Dynamics Observatory (SDO) was launched in 2010. SDO is a sun pointing semi-autonomous spacecraft in a geosynchronous orbit that allows nearly continuous observations of the sun. SDO is equipped with coarse sun sensors, two star trackers, a digital sun sensor, and three two-axis inertial reference units (IRU). The IRUs are temperature sensitive and were designed to operate in a stable thermal environment. Due to battery degradation concerns the IRU heaters were not used on SDO and the onboard filter was tuned to accommodate the noisier IRU data. Since launch currents have increased on two IRUs, one had to eventually be powered off. Recent ground tests on a battery similar to SDO indicated the heaters would have negligible impact on battery degradation, so in 2016 a decision was made to turn the heaters on. This paper presents the analysis and results of updating the filter tuning parameters onboard SDO with the IRUs now operating in their intended thermal environment.

  5. Solar Dynamics Observatory Guidance, Navigation, and Control System Overview

    Science.gov (United States)

    Morgenstern, Wendy M.; Bourkland, Kristin L.; Hsu, Oscar C.; Liu, Kuo-Chia; Mason, Paul A. C.; O'Donnell, James R., Jr.; Russo, Angela M.; Starin, Scott R.; Vess, Melissa F.

    2011-01-01

    The Solar Dynamics Observatory (SDO) was designed and built at the Goddard Space Flight Center, launched from Cape Canaveral on February 11, 2010, and reached its final geosynchronous science orbit on March 16, 2010. The purpose of SDO is to observe the Sun and continuously relay data to a dedicated ground station. SDO remains Sun-pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system (ACS) is a single-fault tolerant design. Its fully redundant attitude sensor complement includes sixteen coarse Sun sensors (CSSs), a digital Sun sensor (DSS), three two-axis inertial reference units (IRUs), and two star trackers (STs). The ACS also makes use of the four guide telescopes included as a part of one of the science instruments. Attitude actuation is performed using four reaction wheels assemblies (RWAs) and eight thrusters, with a single main engine used to provide velocity-change thrust for orbit raising. The attitude control software has five nominal control modes, three wheel-based modes and two thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. This paper details the final overall design of the SDO guidance, navigation, and control (GN&C) system and how it was used in practice during SDO launch, commissioning, and nominal operations. This overview will include the ACS control modes, attitude determination and sensor calibration, the high gain antenna (HGA) calibration, and jitter mitigation operation. The Solar Dynamics Observatory mission is part of the NASA Living With a Star program, which seeks to understand the changing Sun and its effects on the Solar System, life, and society. To this end, the SDO spacecraft carries three Sun

  6. The Solar Dynamics Observatory, Studying the Sun and Its Influence on Other Bodies in the Solar System

    Science.gov (United States)

    Chamberlin, P. C.

    2011-01-01

    The solar photon output, which was once thought to be constant, varies over all time scales from seconds during solar flares to years due to the solar cycle. These solar variations cause significant deviations in the Earth and space environments on similar time scales, such as affecting the atmospheric densities and composition of particular atoms, molecules, and ions in the atmospheres of the Earth and other planets. Presented and discussed will be examples of unprecedented observations from NASA's new solar observatory, the Solar Dynamics Observatory (SDO). Using three specialized instruments, SDO measures the origins of solar activity from inside the Sun, though its atmosphere, then accurately measuring the Sun's radiative output in X-ray and EUV wavelengths (0.1-121 nm). Along with the visually appealing observations will be discussions of what these measurements can tell us about how the plasma motions in all layers of the Sun modifies and strengthens the weak solar dipole magnetic field to drive large energy releases in solar eruptions. Also presented will be examples of how the release of the Sun's energy, in the form of photons and high energy particles, physically influence other bodies in the solar system such as Earth, Mars, and the Moon, and how these changes drive changes in the technology that we are becoming dependent upon. The presentation will continuously emphasize how SDO, the first satellite in NASA's Living with a Star program, improving our understanding of the variable Sun and its Heliospheric influence.

  7. The Effects of Propellant Slosh Dynamics on the Solar Dynamics Observatory

    Science.gov (United States)

    Mason, Paul; Starin, Scott R.

    2011-01-01

    The Solar Dynamics Observatory (SDO) mission, which is part of the Living With a Star program, was successfully launched and deployed from its Atlas V launch vehicle on February 11, 2010. SDO is an Explorer-class mission now operating in a geosynchronous orbit (GEO). The basic mission is to observe the Sun for a very high percentage of the 5-year mission (10-year goal) with long stretches of uninterrupted observations and with constant, high-data-rate transmission to a dedicated ground station located in White Sands, New Mexico. A significant portion of SDO's launch mass was propellant, contained in two large tanks. To ensure performance with this level of propellant, a slosh analysis was performed. This paper provides an overview of the SDO slosh analysis, the on-orbit experience, and the lessons learned. SDO is a three-axis controlled, single fault tolerant spacecraft. The attitude sensor complement includes sixteen coarse Sun sensors, a digital Sun sensor, three two-axis inertial reference units, two star trackers, and four guide telescopes. Attitude actuation is performed either using four reaction wheels or eight thrusters, depending on the control mode, along with single main engine which nominally provides velocity-change thrust. The attitude control software has five nominal control modes: three wheel-based modes and two thruster-based modes. A wheel-based Safehold running in the Attitude Control Electronics (ACE) box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. To achieve and maintain a geosynchronous orbit for a 2974-kilogram spacecraft in a cost effective manner, the SDO team designed a high-efficiency propulsive system. This bi-propellant design includes a 100-pound-force main engine and eight 5-pound-force attitude control thrusters. The main engine provides high specific impulse for

  8. Fault Detection and Correction for the Solar Dynamics Observatory Attitude Control System

    Science.gov (United States)

    Starin, Scott R.; Vess, Melissa F.; Kenney, Thomas M.; Maldonado, Manuel D.; Morgenstern, Wendy M.

    2007-01-01

    The Solar Dynamics Observatory is an Explorer-class mission that will launch in early 2009. The spacecraft will operate in a geosynchronous orbit, sending data 24 hours a day to a devoted ground station in White Sands, New Mexico. It will carry a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly includes four telescopes with focal plane CCDs that can image the full solar disk in four different visible wavelengths. The Extreme-ultraviolet Variability Experiment will collect time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager will enable study of pressure waves moving through the body of the Sun. The attitude control system on Solar Dynamics Observatory is responsible for four main phases of activity. The physical safety of the spacecraft after separation must be guaranteed. Fine attitude determination and control must be sufficient for instrument calibration maneuvers. The mission science mode requires 2-arcsecond control according to error signals provided by guide telescopes on the Atmospheric Imaging Assembly, one of the three instruments to be carried. Lastly, accurate execution of linear and angular momentum changes to the spacecraft must be provided for momentum management and orbit maintenance. In thsp aper, single-fault tolerant fault detection and correction of the Solar Dynamics Observatory attitude control system is described. The attitude control hardware suite for the mission is catalogued, with special attention to redundancy at the hardware level. Four reaction wheels are used where any three are satisfactory. Four pairs of redundant thrusters are employed for orbit change maneuvers and momentum management. Three two-axis gyroscopes provide full redundancy for rate sensing. A digital Sun sensor and two autonomous star trackers provide two-out-of-three redundancy for fine attitude determination. The use of software to maximize

  9. Data Distribution System (DDS) and Solar Dynamic Observatory Ground Station (SDOGS) Integration Manager

    Science.gov (United States)

    Pham, Kim; Bialas, Thomas

    2012-01-01

    The DDS SDOGS Integration Manager (DSIM) provides translation between native control and status formats for systems within DDS and SDOGS, and the ASIST (Advanced Spacecraft Integration and System Test) control environment in the SDO MOC (Solar Dynamics Observatory Mission Operations Center). This system was created in response for a need to centralize remote monitor and control of SDO Ground Station equipments using ASIST control environment in SDO MOC, and to have configurable table definition for equipment. It provides translation of status and monitoring information from the native systems into ASIST-readable format to display on pages in the MOC. The manager is lightweight, user friendly, and efficient. It allows data trending, correlation, and storing. It allows using ASIST as common interface for remote monitor and control of heterogeneous equipments. It also provides failover capability to back up machines.

  10. A Survey of Nanoflare Properties in Active Regions Observed with the Solar Dynamics Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Viall, Nicholeen M.; Klimchuk, James A. [NASA Goddard Space Flight Center, Solar Physics Laboratory, Greenbelt, MD 20771 (United States)

    2017-06-20

    In this paper, we examine 15 different active regions (ARs) observed with the Solar Dynamics Observatory and analyze their nanoflare properties. We have recently developed a technique that systematically identifies and measures plasma temperature dynamics by computing time lags between light curves. The time lag method tests whether the plasma is maintained at a steady temperature, or if it is dynamic, undergoing heating and cooling cycles. An important aspect of our technique is that it analyzes both observationally distinct coronal loops as well as the much more prevalent diffuse emission between them. We find that the widespread cooling reported previously for NOAA AR 11082 is a generic property of all ARs. The results are consistent with impulsive nanoflare heating followed by slower cooling. Only occasionally, however, is there full cooling from above 7 MK to well below 1 MK. More often, the plasma cools to approximately 1–2 MK before being reheated by another nanoflare. These same 15 ARs were first studied by Warren et al. We find that the degree of cooling is not well correlated with the reported slopes of the emission measure distribution. We also conclude that the Fe xviii emitting plasma that they measured is mostly in a state of cooling. These results support the idea that nanoflares have a distribution of energies and frequencies, with the average delay between successive events on an individual flux tube being comparable to the plasma cooling timescale.

  11. Ellerman bombs observed with the new vacuum solar telescope and the atmospheric imaging assembly onboard the solar dynamics observatory

    Science.gov (United States)

    Chen, Yajie; Tian, Hui; Xu, Zhi; Xiang, Yongyuan; Fang, Yuliang; Yang, Zihao

    2017-12-01

    Ellerman bombs (EBs) are believed to be small-scale reconnection events occurring around the temperature minimum region in the solar atmosphere. They are often identified as significant enhancements in the extended Hα wings without obvious signatures in the Hα core. Here we explore the possibility of using the 1700 Å images taken by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) to study EBs. From the Hα wing images obtained with the New Vacuum Solar Telescope (NVST) on 2015 May 2, we have identified 145 EBs and 51% of them clearly correspond to the bright points (BPs) in the AIA 1700 Å images. If we resize the NVST images using a linear interpolation to make the pixel sizes of the AIA and NVST images the same, some previously identified EBs disappear and about 71% of the remaining EBs are associated with BPs. Meanwhile, 66% of the compact brightenings in the AIA 1700 Å images can be identified as EBs in the Hα wings. The intensity enhancements of the EBs in the Hα wing images reveal a linear correlation with those of the BPs in the AIA 1700 Å images. Our study suggests that a significant fraction of EBs can be observed with the AIA 1700 Å filter, which is promising for large-sample statistical study of EBs as the seeing-free and full-disk SDO/AIA data are routinely available.

  12. Flare Ribbons Approach Observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ting; Zhang, Jun; Hou, Yijun, E-mail: liting@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2017-10-10

    We report flare ribbons approach (FRA) during a multiple-ribbon M-class flare on 2015 November 4 in NOAA AR 12443, obtained by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The flare consisted of a pair of main ribbons and two pairs of secondary ribbons. The two pairs of secondary ribbons were formed later than the appearance of the main ribbons, with respective time delays of 15 and 19 minutes. The negative-polarity main ribbon spread outward faster than the first secondary ribbon with the same polarity in front of it, and thus the FRA was generated. Just before their encounter, the main ribbon was darkening drastically and its intensity decreased by about 70% in 2 minutes, implying the suppression of main-phase reconnection that produced two main ribbons. The FRA caused the deflection of the main ribbon to the direction of secondary ribbon with a deflection angle of about 60°. A post-approach arcade was formed about 2 minutes later and the downflows were detected along the new arcade with velocities of 35–40 km s{sup −1}, indicative of the magnetic restructuring during the process of FRA. We suggest that there are three topological domains with footpoints outlined by the three pairs of ribbons. Close proximity of these domains leads to deflection of the ribbons, which is in agreement with the magnetic field topology.

  13. An extreme ultraviolet wave associated with a failed eruption observed by the Solar Dynamics Observatory

    Science.gov (United States)

    Zheng, R.; Jiang, Y.; Yang, J.; Bi, Y.; Hong, J.; Yang, B.; Yang, D.

    2012-05-01

    Aims: Taking advantage of the high temporal and spatial resolution of the Solar Dynamics Observatory (SDO) observations, we present an extreme ultraviolet (EUV) wave associated with a failed filament eruption that generated no coronal mass ejection (CME) on 2011 March 1. We aim at understanding the nature and origin of this EUV wave. Methods: Combining the high-quality observations in the photosphere, the chromosphere, and the corona, we studied the characteristics of the wave and its relations to the associated eruption. Results: The event occurred at an ephemeral region near a small active region. The continuous magnetic flux cancelation in the ephemeral region produced pre-eruption brightenings and two EUV jets, and excited the filament eruption, accompanying it with a microflare. After the eruption, the filament material appeared far from the eruption center, and the ambient loops seemed to be intact. It was evident that the filament eruption had failed and was not associated with a CME. The wave happened just after the north jet arrived, and apparently emanated ahead of the north jet, far from the eruption center. The wave propagated at nearly constant velocities in the range of 260-350 km s-1, with a slight negative acceleration in the last phase. Remarkably, the wave continued to propagate, and a loop in its passage was intact when wave and loop met. Conclusions: Our analysis confirms that the EUV wave is a true wave, which we interpret as a fast-mode wave. In addition, the close temporal and spatial relationship between the wave and the jet provides evidence that the wave was likely triggered by the jet when the CME failed to happen. Three movies are available in electronic form at http://www.aanda.org

  14. On-Orbit Performance of the Helioseismic and Magnetic Imager Instrument onboard the Solar Dynamics Observatory

    Science.gov (United States)

    Hoeksema, J. T.; Baldner, C. S.; Bush, R. I.; Schou, J.; Scherrer, P. H.

    2018-03-01

    The Helioseismic and Magnetic Imager (HMI) instrument is a major component of NASA's Solar Dynamics Observatory (SDO) spacecraft. Since commencement of full regular science operations on 1 May 2010, HMI has operated with remarkable continuity, e.g. during the more than five years of the SDO prime mission that ended 30 September 2015, HMI collected 98.4% of all possible 45-second velocity maps; minimizing gaps in these full-disk Dopplergrams is crucial for helioseismology. HMI velocity, intensity, and magnetic-field measurements are used in numerous investigations, so understanding the quality of the data is important. This article describes the calibration measurements used to track the performance of the HMI instrument, and it details trends in important instrument parameters during the prime mission. Regular calibration sequences provide information used to improve and update the calibration of HMI data. The set-point temperature of the instrument front window and optical bench is adjusted regularly to maintain instrument focus, and changes in the temperature-control scheme have been made to improve stability in the observable quantities. The exposure time has been changed to compensate for a 20% decrease in instrument throughput. Measurements of the performance of the shutter and tuning mechanisms show that they are aging as expected and continue to perform according to specification. Parameters of the tunable optical-filter elements are regularly adjusted to account for drifts in the central wavelength. Frequent measurements of changing CCD-camera characteristics, such as gain and flat field, are used to calibrate the observations. Infrequent expected events such as eclipses, transits, and spacecraft off-points interrupt regular instrument operations and provide the opportunity to perform additional calibration. Onboard instrument anomalies are rare and seem to occur quite uniformly in time. The instrument continues to perform very well.

  15. Investigating On-Orbit Attitude Determination Anomalies for the Solar Dynamics Observatory Mission

    Science.gov (United States)

    Vess, Melissa F.; Starin, Scott R.; Chia-Kuo, Alice Liu

    2011-01-01

    The Solar Dynamics Observatory (SDO) was launched on February 11, 2010 from Kennedy Space Center on an Atlas V launch vehicle into a geosynchronous transfer orbit. SDO carries a suite of three scientific instruments, whose observations are intended to promote a more complete understanding of the Sun and its effects on the Earth's environment. After a successful launch, separation, and initial Sun acquisition, the launch and flight operations teams dove into a commissioning campaign that included, among other things, checkout and calibration of the fine attitude sensors and checkout of the Kalman filter (KF) and the spacecraft s inertial pointing and science control modes. In addition, initial calibration of the science instruments was also accomplished. During that process of KF and controller checkout, several interesting observations were noticed and investigated. The SDO fine attitude sensors consist of one Adcole Digital Sun Sensor (DSS), two Galileo Avionica (GA) quaternion-output Star Trackers (STs), and three Kearfott Two-Axis Rate Assemblies (hereafter called inertial reference units, or IRUs). Initial checkout of the fine attitude sensors indicated that all sensors appeared to be functioning properly. Initial calibration maneuvers were planned and executed to update scale factors, drift rate biases, and alignments of the IRUs. After updating the IRU parameters, the KF was initialized and quickly reached convergence. Over the next few hours, it became apparent that there was an oscillation in the sensor residuals and the KF estimation of the IRU bias. A concentrated investigation ensued to determine the cause of the oscillations, their effect on mission requirements, and how to mitigate them. The ensuing analysis determined that the oscillations seen were, in fact, due to an oscillation in the IRU biases. The low frequencies of the oscillations passed through the KF, were well within the controller bandwidth, and therefore the spacecraft was actually

  16. The Solar Dynamics Observatory (SDO) Education and Outreach (E/PO) Program: Changing Perceptions One Program at a Time

    Science.gov (United States)

    Drobnes, Emilie; Littleton, A.; Pesnell, William D.; Beck, K.; Buhr, S.; Durscher, R.; Hill, S.; McCaffrey, M.; McKenzie, D. E.; Myers, D.; hide

    2013-01-01

    We outline the context and overall philosophy for the combined Solar Dynamics Observatory (SDO) Education and Public Outreach (E/PO) program, present a brief overview of all SDO E/PO programs along with more detailed highlights of a few key programs, followed by a review of our results to date, conclude a summary of the successes, failures, and lessons learned, which future missions can use as a guide, while incorporating their own content to enhance the public's knowledge and appreciation of science and technology as well as its benefit to society.

  17. On-Orbit Solar Dynamics Observatory (SDO) Star Tracker Warm Pixel Analysis

    Science.gov (United States)

    Felikson, Denis; Ekinci, Matthew; Hashmall, Joseph A.; Vess, Melissa

    2011-01-01

    This paper describes the process of identification and analysis of warm pixels in two autonomous star trackers on the Solar Dynamics Observatory (SDO) mission. A brief description of the mission orbit and attitude regimes is discussed and pertinent star tracker hardware specifications are given. Warm pixels are defined and the Quality Index parameter is introduced, which can be explained qualitatively as a manifestation of a possible warm pixel event. A description of the algorithm used to identify warm pixel candidates is given. Finally, analysis of dumps of on-orbit star tracker charge coupled devices (CCD) images is presented and an operational plan going forward is discussed. SDO, launched on February 11, 2010, is operated from the NASA Goddard Space Flight Center (GSFC). SDO is in a geosynchronous orbit with a 28.5 inclination. The nominal mission attitude points the spacecraft X-axis at the Sun, with the spacecraft Z-axis roughly aligned with the Solar North Pole. The spacecraft Y-axis completes the triad. In attitude, SDO moves approximately 0.04 per hour, mostly about the spacecraft Z-axis. The SDO star trackers, manufactured by Galileo Avionica, project the images of stars in their 16.4deg x 16.4deg fields-of-view onto CCD detectors consisting of 512 x 512 pixels. The trackers autonomously identify the star patterns and provide an attitude estimate. Each unit is able to track up to 9 stars. Additionally, each tracker calculates a parameter called the Quality Index, which is a measure of the quality of the attitude solution. Each pixel in the CCD measures the intensity of light and a warns pixel is defined as having a measurement consistently and significantly higher than the mean background intensity level. A warns pixel should also have lower intensity than a pixel containing a star image and will not move across the field of view as the attitude changes (as would a dim star image). It should be noted that the maximum error introduced in the star tracker

  18. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots. 13 references

  19. Solar and Heliospheric Observatory (SOHO) Flight Dynamics Simulations Using MATLAB (R)

    Science.gov (United States)

    Headrick, R. D.; Rowe, J. N.

    1996-01-01

    This paper describes a study to verify onboard attitude control laws in the coarse Sun-pointing (CSP) mode by simulation and to develop procedures for operational support for the Solar and Heliospheric Observatory (SOHO) mission. SOHO was launched on December 2, 1995, and the predictions of the simulation were verified with the flight data. This study used a commercial off the shelf product MATLAB(tm) to do the following: Develop procedures for computing the parasitic torques for orbital maneuvers; Simulate onboard attitude control of roll, pitch, and yaw during orbital maneuvers; Develop procedures for predicting firing time for both on- and off-modulated thrusters during orbital maneuvers; Investigate the use of feed forward or pre-bias torques to reduce the attitude handoff during orbit maneuvers - in particular, determine how to use the flight data to improve the feed forward torque estimates for use on future maneuvers. The study verified the stability of the attitude control during orbital maneuvers and the proposed use of feed forward torques to compensate for the attitude handoff. Comparison of the simulations with flight data showed: Parasitic torques provided a good estimate of the on- and off-modulation for attitude control; The feed forward torque compensation scheme worked well to reduce attitude handoff during the orbital maneuvers. The work has been extended to prototype calibration of thrusters from observed firing time and observed reaction wheel speed changes.

  20. Design and Ground Calibration of the Helioseismic and Magnetic Imager (HMI) Instrument on the Solar Dynamics Observatory (SDO)

    Science.gov (United States)

    Schou, J.; Scherrer, P. H.; Bush, R. I.; Wachter, R.; Couvidat, S.; Rabello-Soares, M. C.; Bogart, R. S.; Hoeksema, J. T.; Liu, Y.; Duvall, T. L., Jr.; hide

    2012-01-01

    The Helioseismic and Magnetic Imager (HMI) investigation will study the solar interior using helioseismic techniques as well as the magnetic field near the solar surface. The HMI instrument is part of the Solar Dynamics Observatory (SDO) that was launched on 11 February 2010. The instrument is designed to measure the Doppler shift, intensity, and vector magnetic field at the solar photosphere using the 6173 Fe I absorption line. The instrument consists of a front-window filter, a telescope, a set of wave plates for polarimetry, an image-stabilization system, a blocking filter, a five-stage Lyot filter with one tunable element, two wide-field tunable Michelson interferometers, a pair of 4096(exo 2) pixel cameras with independent shutters, and associated electronics. Each camera takes a full-disk image roughly every 3.75 seconds giving an overall cadence of 45 seconds for the Doppler, intensity, and line-of-sight magnetic-field measurements and a slower cadence for the full vector magnetic field. This article describes the design of the HMI instrument and provides an overview of the pre-launch calibration efforts. Overviews of the investigation, details of the calibrations, data handling, and the science analysis are provided in accompanying articles.

  1. Utilization of Solar Dynamics Observatory space weather digital image data for comparative analysis with application to Baryon Oscillation Spectroscopic Survey

    Science.gov (United States)

    Shekoyan, V.; Dehipawala, S.; Liu, Ernest; Tulsee, Vivek; Armendariz, R.; Tremberger, G.; Holden, T.; Marchese, P.; Cheung, T.

    2012-10-01

    Digital solar image data is available to users with access to standard, mass-market software. Many scientific projects utilize the Flexible Image Transport System (FITS) format, which requires specialized software typically used in astrophysical research. Data in the FITS format includes photometric and spatial calibration information, which may not be useful to researchers working with self-calibrated, comparative approaches. This project examines the advantages of using mass-market software with readily downloadable image data from the Solar Dynamics Observatory for comparative analysis over with the use of specialized software capable of reading data in the FITS format. Comparative analyses of brightness statistics that describe the solar disk in the study of magnetic energy using algorithms included in mass-market software have been shown to give results similar to analyses using FITS data. The entanglement of magnetic energy associated with solar eruptions, as well as the development of such eruptions, has been characterized successfully using mass-market software. The proposed algorithm would help to establish a publicly accessible, computing network that could assist in exploratory studies of all FITS data. The advances in computer, cell phone and tablet technology could incorporate such an approach readily for the enhancement of high school and first-year college space weather education on a global scale. Application to ground based data such as that contained in the Baryon Oscillation Spectroscopic Survey is discussed.

  2. Verification of the Solar Dynamics Observatory High Gain Antenna Pointing Algorithm Using Flight Data

    Science.gov (United States)

    Bourkland, Kristin L.; Liu, Kuo-Chia

    2011-01-01

    The Solar Dynamics Observatory (SDO) is a NASA spacecraft designed to study the Sun. It was launched on February 11, 2010 into a geosynchronous orbit, and uses a suite of attitude sensors and actuators to finely point the spacecraft at the Sun. SDO has three science instruments: the Atmospheric Imaging Assembly (AIA), the Helioseismic and Magnetic Imager (HMI), and the Extreme Ultraviolet Variability Experiment (EVE). SDO uses two High Gain Antennas (HGAs) to send science data to a dedicated ground station in White Sands, New Mexico. In order to meet the science data capture budget, the HGAs must be able to transmit data to the ground for a very large percentage of the time. Each HGA is a dual-axis antenna driven by stepper motors. Both antennas transmit data at all times, but only a single antenna is required in order to meet the transmission rate requirement. For portions of the year, one antenna or the other has an unobstructed view of the White Sands ground station. During other periods, however, the view from both antennas to the Earth is blocked for different portions of the day. During these times of blockage, the two HGAs take turns pointing to White Sands, with the other antenna pointing out to space. The HGAs handover White Sands transmission responsibilities to the unblocked antenna. There are two handover seasons per year, each lasting about 72 days, where the antennas hand off control every twelve hours. The non-tracking antenna slews back to the ground station by following a ground commanded trajectory and arrives approximately 5 minutes before the formerly tracking antenna slews away to point out into space. The SDO Attitude Control System (ACS) runs at 5 Hz, and the HGA Gimbal Control Electronics (GCE) run at 200 Hz. There are 40 opportunities for the gimbals to step each ACS cycle, with a hardware limitation of no more than one step every three GCE cycles. The ACS calculates the desired gimbal motion for tracking the ground station or for slewing

  3. Tracking a Solar Wind Dynamic Pressure Pulses' Impact Through the Magnetosphere Using the Heliophysics System Observatory

    Science.gov (United States)

    Vidal-Luengo, S.; Moldwin, M.

    2017-12-01

    During northward Interplanetary Magnetic Field (IMF) Bz conditions, the magnetosphere acts as a closed "cavity" and reacts to solar wind dynamic pressure pulses more simply than during southward IMF conditions. Effects of solar wind dynamic pressure have been observed as geomagnetic lobe compressions depending on the characteristics of the pressure pulse and the spacecraft location. One of the most important aspects of this study is the incorporation of simultaneous observations by different missions, such as WIND, CLUSTER, THEMIS, MMS, Van Allen Probes and GOES as well as magnetometer ground stations that allow us to map the magnetosphere response at different locations during the propagation of a pressure pulse. In this study we used the SYM-H as an indicator of dynamic pressure pulses occurrence from 2007 to 2016. The selection criteria for events are: (1) the increase in the index must be bigger than 10 [nT] and (2) the rise time must be in less than 5 minutes. Additionally, the events must occur under northward IMF and at the same time at least one spacecraft has to be located in the magnetosphere nightside. Using this methodology we found 66 pressure pulse events for analysis. Most of them can be classified as step function pressure pulses or as sudden impulses (increase followed immediately by a decrease of the dynamic pressure). Under these two categories the results show some systematic signatures depending of the location of the spacecraft. For both kind of pressure pulse signatures, compressions are observed on the dayside. However, on the nightside compressions and/or South-then-North magnetic signatures can be observed for step function like pressure pulses, meanwhile for the sudden impulse kind of pressure pulses the magnetospheric response seems to be less global and more dependent on the local conditions.

  4. The Solar Connections Observatory for Planetary Environments

    Science.gov (United States)

    Oliversen, Ronald J.; Harris, Walter M.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    The NASA Sun-Earth Connection theme roadmap calls for comparative study of how the planets, comets, and local interstellar medium (LISM) interact with the Sun and respond to solar variability. Through such a study we advance our understanding of basic physical plasma and gas dynamic processes, thus increasing our predictive capabilities for the terrestrial, planetary, and interplanetary environments where future remote and human exploration will occur. Because the other planets have lacked study initiatives comparable to the terrestrial ITM, LWS, and EOS programs, our understanding of the upper atmospheres and near space environments on these worlds is far less detailed than our knowledge of the Earth. To close this gap we propose a mission to study {\\it all) of the solar interacting bodies in our planetary system out to the heliopause with a single remote sensing space observatory, the Solar Connections Observatory for Planetary Environments (SCOPE). SCOPE consists of a binocular EUV/FUV telescope operating from a remote, driftaway orbit that provides sub-arcsecond imaging and broadband medium resolution spectro-imaging over the 55-290 nm bandpass, and high (R>10$^{5}$ resolution H Ly-$\\alpha$ emission line profile measurements of small scale planetary and wide field diffuse solar system structures. A key to the SCOPE approach is to include Earth as a primary science target. From its remote vantage point SCOPE will be able to observe auroral emission to and beyond the rotational pole. The other planets and comets will be monitored in long duration campaigns centered when possible on solar opposition when interleaved terrestrial-planet observations can be used to directly compare the response of both worlds to the same solar wind stream and UV radiation field. Using a combination of observations and MHD models, SCOPE will isolate the different controlling parameters in each planet system and gain insight into the underlying physical processes that define the

  5. Think Scientifically: The NASA Solar Dynamics Observatory's Elementary Science Literacy Program

    Science.gov (United States)

    Van Norden, Wendy M.

    2013-07-01

    The pressure to focus on math and reading at the elementary level has increased in recent years. As a result, science education has taken a back seat in elementary classrooms. The Think Scientifically book series provides a way for science to easily integrate with existing math and reading curriculum. This story-based science literature program integrates a classic storybook format with solar science concepts, to make an educational product that meets state literacy standards. Each story is accompanied by hands-on labs and activities that teachers can easily conduct in their classrooms with minimal training and materials, as well as math and language arts extensions. These books are being distributed through teacher workshops and conferences, and are available free at http://sdo.gsfc.nasa.gov/epo/educators/thinkscientifically.php.

  6. A systematic desaturation method for images from the Atmospheric Imaging Assembly in the Solar Dynamics Observatory.

    Science.gov (United States)

    Torre, Gabriele; Schwartz, Richard; Piana, Michele; Massone, Anna Maria; Benvenuto, Federico

    2016-05-01

    The fine spatial resolution of the SDO AIA CCD's is often destroyed by the charge in saturated pixels overflowing into a swath of neighboring cells during fast rising solar flares. Automated exposure control can only mitigate this issue to a degree and it has other deleterious effects. Our method addresses the desaturation problem for AIA images as an image reconstruction problem in which the information content of the diffraction fringes, generated by the interaction between the incoming radiation and the hardware of the spacecraft, is exploited to recover the true image intensities within the primary saturated core of the image. This methodology takes advantage of some well defined techniques like cross-correlation and the Expectation Maximization method to invert the direct relation between the diffraction fringes intensities and the true flux intensities. During this talk a complete overview on the structure of the method will be provided, besides some reliability tests obtained by its application against synthetic and real data.

  7. Design and Development of the Solar Dynamics Observatory (SDO) Electrical Power System

    Science.gov (United States)

    Denney, Keys; Burns, Michael; Kercheval, Bradford

    2009-01-01

    The SDO spacecraft was designed to help us understand the Sun's influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously. It will perform its operations in a geosynchronous orbit of the earth. This paper will present background on the SDO mission, an overview of the design and development activities associated specifically with the SDO electrical power system (EPS), as well as the major driving requirements behind the mission design. The primary coverage of the paper will be devoted to some of the challenges faced during the design and development phase. This will include the challenges associated with development of a compatible CompactPCI (cPCI) interface within the Power System Electronics (PSE) in order to utilize a "common" processor card, implementation of new solid state power controllers (SSPC) for primary load distribution switching and over current protection in the PSE, and the design approach adopted to meet single fault tolerance requirements for all of the SDO EPS functions.

  8. OSCILLATION OF CURRENT SHEETS IN THE WAKE OF A FLUX ROPE ERUPTION OBSERVED BY THE SOLAR DYNAMICS OBSERVATORY

    Energy Technology Data Exchange (ETDEWEB)

    Li, L. P.; Zhang, J.; Su, J. T. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, 100012 Beijing (China); Liu, Y. [Department of Astronomy, Beijing Normal University, 100875 Beijing (China)

    2016-10-01

    An erupting flux rope (FR) draws its overlying coronal loops upward, causing a coronal mass ejection. The legs of the overlying loops with opposite polarities are driven together. Current sheets (CSs) form, and magnetic reconnection, producing underneath flare arcades, occurs in the CSs. Employing Solar Dynamic Observatory /Atmospheric Imaging Assembly images, we study a FR eruption on 2015 April 23, and for the first time report the oscillation of CSs underneath the erupting FR. The FR is observed in all AIA extreme-ultraviolet passbands, indicating that it has both hot and warm components. Several bright CSs, connecting the erupting FR and the underneath flare arcades, are observed only in hotter AIA channels, e.g., 131 and 94 Å. Using the differential emission measure (EM) analysis, we find that both the temperature and the EM of CSs temporally increase rapidly, reach the peaks, and then decrease slowly. A significant delay between the increases of the temperature and the EM is detected. The temperature, EM, and density spatially decrease along the CSs with increasing heights. For a well-developed CS, the temperature (EM) decreases from 9.6 MK (8 × 10{sup 28} cm{sup −5}) to 6.2 MK (5 × 10{sup 27} cm{sup −5}) in 52 Mm. Along the CSs, dark supra-arcade downflows (SADs) are observed, and one of them separates a CS into two. While flowing sunward, the speeds of the SADs decrease. The CSs oscillate with a period of 11 minutes, an amplitude of 1.5 Mm, and a phase speed of 200 ± 30 km s{sup −1}. One of the oscillations lasts for more than 2 hr. These oscillations represent fast-propagating magnetoacoustic kink waves.

  9. The Carl Sagan solar and stellar observatories as remote observatories

    Science.gov (United States)

    Saucedo-Morales, J.; Loera-Gonzalez, P.

    In this work we summarize recent efforts made by the University of Sonora, with the goal of expanding the capability for remote operation of the Carl Sagan Solar and Stellar Observatories, as well as the first steps that have been taken in order to achieve autonomous robotic operation in the near future. The solar observatory was established in 2007 on the university campus by our late colleague A. Sánchez-Ibarra. It consists of four solar telescopes mounted on a single equatorial mount. On the other hand, the stellar observatory, which saw the first light on 16 February 2010, is located 21 km away from Hermosillo, Sonora at the site of the School of Agriculture of the University of Sonora. Both observatories can now be remotely controlled, and to some extent are able to operate autonomously. In this paper we discuss how this has been accomplished in terms of the use of software as well as the instruments under control. We also briefly discuss the main scientific and educational objectives, the future plans to improve the control software and to construct an autonomous observatory on a mountain site, as well as the opportunities for collaborations.

  10. Solar Imagery - Photosphere - Sunspot Drawings - McMath-Hulbert Observatory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The McMath-Hulbert Observatory is a decommissioned solar observatory in Lake Angelus, Michigan, USA. It was established in 1929 as a private observatory by father...

  11. The Malaysian Robotic Solar Observatory (P29)

    Science.gov (United States)

    Othman, M.; Asillam, M. F.; Ismail, M. K. H.

    2006-11-01

    Robotic observatory with small telescopes can make significant contributions to astronomy observation. They provide an encouraging environment for astronomers to focus on data analysis and research while at the same time reducing time and cost for observation. The observatory will house the primary 50cm robotic telescope in the main dome which will be used for photometry, spectroscopy and astrometry observation activities. The secondary telescope is a robotic multi-apochromatic refractor (maximum diameter: 15 cm) which will be housed in the smaller dome. This telescope set will be used for solar observation mainly in three different wavelengths simultaneously: the Continuum, H-Alpha and Calcium K-line. The observatory is also equipped with an automated weather station, cloud & rain sensor and all-sky camera to monitor the climatic condition, sense the clouds (before raining) as well as to view real time sky view above the observatory. In conjunction with the Langkawi All-Sky Camera, the observatory website will also display images from the Malaysia - Antarctica All-Sky Camera used to monitor the sky at Scott Base Antarctica. Both all-sky images can be displayed simultaneously to show the difference between the equatorial and Antarctica skies. This paper will describe the Malaysian Robotic Observatory including the systems available and method of access by other astronomers. We will also suggest possible collaboration with other observatories in this region.

  12. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Solar Dynamics Observatory-Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, Thomas L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2010-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler-velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time - distance helioseismology pipeline (Zhao et al., Solar Phys. submitted, 2010) has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross-covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time - distance helioseismology: a Gabor-wavelet fitting (Kosovichev and Duvall, SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, Astrophys. J. 571, 966, 2002), and a linearized version of the minimization method (Gizon and Birch, Astrophys. J. 614, 472, 2004). Using Doppler-velocity data from the Michelson Doppler Imager (MDI) instrument onboard SOHO, we tested and compared these definitions for the mean and difference traveltime perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet-Sun region, the method of Gizon and Birch (Astrophys. J. 614, 472, 2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997) and Gizon and Birch (Astrophys. J. 571, 966, 2002). We investigated the relationships among

  13. THERMAL DIAGNOSTICS WITH THE ATMOSPHERIC IMAGING ASSEMBLY ON BOARD THE SOLAR DYNAMICS OBSERVATORY: A VALIDATED METHOD FOR DIFFERENTIAL EMISSION MEASURE INVERSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Mark C. M.; Boerner, P.; Schrijver, C. J.; Malanushenko, A. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street Bldg. 252, Palo Alto, CA 94304 (United States); Testa, P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chen, F.; Peter, H., E-mail: cheung@lmsal.com [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2015-07-10

    We present a new method for performing differential emission measure (DEM) inversions on narrow-band EUV images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. The method yields positive definite DEM solutions by solving a linear program. This method has been validated against a diverse set of thermal models of varying complexity and realism. These include (1) idealized Gaussian DEM distributions, (2) 3D models of NOAA Active Region 11158 comprising quasi-steady loop atmospheres in a nonlinear force-free field, and (3) thermodynamic models from a fully compressible, 3D MHD simulation of active region (AR) corona formation following magnetic flux emergence. We then present results from the application of the method to AIA observations of Active Region 11158, comparing the region's thermal structure on two successive solar rotations. Additionally, we show how the DEM inversion method can be adapted to simultaneously invert AIA and Hinode X-ray Telescope data, and how supplementing AIA data with the latter improves the inversion result. The speed of the method allows for routine production of DEM maps, thus facilitating science studies that require tracking of the thermal structure of the solar corona in time and space.

  14. The Virtual Solar Observatory: Progress and Diversions

    Science.gov (United States)

    Gurman, Joseph B.; Bogart, R. S.; Amezcua, A.; Hill, Frank; Oien, Niles; Davey, Alisdair R.; Hourcle, Joseph; Mansky, E.; Spencer, Jennifer L.

    2017-08-01

    The Virtual Solar Observatory (VSO) is a known and useful method for identifying and accessing solar physics data online. We review current "behind the scenes" work on the VSO, including the addition of new data providers and the return of access to data sets to which service was temporarily interrupted. We also report on the effect on software development efforts when government IT “security” initiatives impinge on finite resoruces. As always, we invite SPD members to identify data sets, services, and interfaces they would like to see implemented in the VSO.

  15. Systems approach to the design of the CCD sensors and camera electronics for the AIA and HMI instruments on solar dynamics observatory

    Science.gov (United States)

    Waltham, N.; Beardsley, S.; Clapp, M.; Lang, J.; Jerram, P.; Pool, P.; Auker, G.; Morris, D.; Duncan, D.

    2017-11-01

    Solar Dynamics Observatory (SDO) is imaging the Sun in many wavelengths near simultaneously and with a resolution ten times higher than the average high-definition television. In this paper we describe our innovative systems approach to the design of the CCD cameras for two of SDO's remote sensing instruments, the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI). Both instruments share use of a custom-designed 16 million pixel science-grade CCD and common camera readout electronics. A prime requirement was for the CCD to operate with significantly lower drive voltages than before, motivated by our wish to simplify the design of the camera readout electronics. Here, the challenge lies in the design of circuitry to drive the CCD's highly capacitive electrodes and to digitize its analogue video output signal with low noise and to high precision. The challenge is greatly exacerbated when forced to work with only fully space-qualified, radiation-tolerant components. We describe our systems approach to the design of the AIA and HMI CCD and camera electronics, and the engineering solutions that enabled us to comply with both mission and instrument science requirements.

  16. OBSERVATIONS OF FIVE-MINUTE SOLAR OSCILLATIONS IN THE CORONA USING THE EXTREME ULTRAVIOLET SPECTROPHOTOMETER (ESP) ON BOARD THE SOLAR DYNAMICS OBSERVATORY EXTREME ULTRAVIOLET VARIABILITY EXPERIMENT (SDO/EVE)

    International Nuclear Information System (INIS)

    Didkovsky, L.; Judge, D.; Wieman, S.; Kosovichev, A. G.; Woods, T.

    2011-01-01

    We report on the detection of oscillations in the corona in the frequency range corresponding to five-minute acoustic modes of the Sun. The oscillations have been observed using soft X-ray measurements from the Extreme Ultraviolet Spectrophotometer (ESP) of the Extreme Ultraviolet Variability Experiment on board the Solar Dynamics Observatory. The ESP zeroth-order channel observes the Sun as a star without spatial resolution in the wavelength range of 0.1-7.0 nm (the energy range is 0.18-12.4 keV). The amplitude spectrum of the oscillations calculated from six-day time series shows a significant increase in the frequency range of 2-4 mHz. We interpret this increase as a response of the corona to solar acoustic (p) modes and attempt to identify p-mode frequencies among the strongest peaks. Due to strong variability of the amplitudes and frequencies of the five-minute oscillations in the corona, we study how the spectrum from two adjacent six-day time series combined together affects the number of peaks associated with the p-mode frequencies and their amplitudes. This study shows that five-minute oscillations of the Sun can be observed in the corona in variations of the soft X-ray emission. Further investigations of these oscillations may improve our understanding of the interaction of the oscillation modes with the solar atmosphere, and the interior-corona coupling, in general.

  17. GROSS- GAMMA RAY OBSERVATORY ATTITUDE DYNAMICS SIMULATOR

    Science.gov (United States)

    Garrick, J.

    1994-01-01

    The Gamma Ray Observatory (GRO) spacecraft will constitute a major advance in gamma ray astronomy by offering the first opportunity for comprehensive observations in the range of 0.1 to 30,000 megaelectronvolts (MeV). The Gamma Ray Observatory Attitude Dynamics Simulator, GROSS, is designed to simulate this mission. The GRO Dynamics Simulator consists of three separate programs: the Standalone Profile Program; the Simulator Program, which contains the Simulation Control Input/Output (SCIO) Subsystem, the Truth Model (TM) Subsystem, and the Onboard Computer (OBC) Subsystem; and the Postprocessor Program. The Standalone Profile Program models the environment of the spacecraft and generates a profile data set for use by the simulator. This data set contains items such as individual external torques; GRO spacecraft, Tracking and Data Relay Satellite (TDRS), and solar and lunar ephemerides; and star data. The Standalone Profile Program is run before a simulation. The SCIO subsystem is the executive driver for the simulator. It accepts user input, initializes parameters, controls simulation, and generates output data files and simulation status display. The TM subsystem models the spacecraft dynamics, sensors, and actuators. It accepts ephemerides, star data, and environmental torques from the Standalone Profile Program. With these and actuator commands from the OBC subsystem, the TM subsystem propagates the current state of the spacecraft and generates sensor data for use by the OBC and SCIO subsystems. The OBC subsystem uses sensor data from the TM subsystem, a Kalman filter (for attitude determination), and control laws to compute actuator commands to the TM subsystem. The OBC subsystem also provides output data to the SCIO subsystem for output to the analysts. The Postprocessor Program is run after simulation is completed. It generates printer and CRT plots and tabular reports of the simulated data at the direction of the user. GROSS is written in FORTRAN 77 and

  18. The COronal Solar Magnetism Observatory (COSMO) Large Aperture Coronagraph

    Science.gov (United States)

    Tomczyk, Steve; Gallagher, Dennis; Wu, Zhen; Zhang, Haiying; Nelson, Pete; Burkepile, Joan; Kolinksi, Don; Sutherland, Lee

    2013-04-01

    The COSMO is a facility dedicated to observing coronal and chromospheric magnetic fields. It will be located on a mountaintop in the Hawaiian Islands and will replace the current Mauna Loa Solar Observatory (MLSO). COSMO will provide unique observations of the global coronal magnetic fields and its environment to enhance the value of data collected by other observatories on the ground (e.g. SOLIS, BBO NST, Gregor, ATST, EST, Chinese Giant Solar Telescope, NLST, FASR) and in space (e.g. SDO, Hinode, SOHO, GOES, STEREO, Solar-C, Solar Probe+, Solar Orbiter). COSMO will employ a fleet of instruments to cover many aspects of measuring magnetic fields in the solar atmosphere. The dynamics and energy flow in the corona are dominated by magnetic fields. To understand the formation of CMEs, their relation to other forms of solar activity, and their progression out into the solar wind requires measurements of coronal magnetic fields. The large aperture coronagraph, the Chromospheric and Prominence Magnetometer and the K-Coronagraph form the COSMO instrument suite to measure magnetic fields and the polarization brightness of the low corona used to infer electron density. The large aperture coronagraph will employ a 1.5 meter fuse silica singlet lens, birefringent filters, and a spectropolarimeter to cover fields of view of up to 1 degree. It will observe the corona over a wide range of emission lines from 530.3 nm through 1083.0 nm allowing for magnetic field measurements over a wide range of coronal temperatures (e.g. FeXIV at 530.3 nm, Fe X at 637.4 nm, Fe XIII at 1074.7 and 1079.8 nm. These lines are faint and require the very large aperture. NCAR and NSF have provided funding to bring the large aperture coronagraph to a preliminary design review state by the end of 2013. As with all data from Mauna Loa, the data products from COSMO will be available to the community via the Mauna Loa website: http://mlso.hao.ucar.edu

  19. The Virtual Solar Observatory and the Heliophysics Meta-Virtual Observatory

    Science.gov (United States)

    Gurman, Joseph B.

    2007-01-01

    The Virtual Solar Observatory (VSO) is now able to search for solar data ranging from the radio to gamma rays, obtained from space and groundbased observatories, from 26 sources at 12 data providers, and from 1915 to the present. The solar physics community can use a Web interface or an Application Programming Interface (API) that allows integrating VSO searches into other software, including other Web services. Over the next few years, this integration will be especially obvious as the NASA Heliophysics division sponsors the development of a heliophysics-wide virtual observatory (VO), based on existing VO's in heliospheric, magnetospheric, and ionospheric physics as well as the VSO. We examine some of the challenges and potential of such a "meta-VO."

  20. Graphics interfaces and numerical simulations: Mexican Virtual Solar Observatory

    Science.gov (United States)

    Hernández, L.; González, A.; Salas, G.; Santillán, A.

    2007-08-01

    Preliminary results associated to the computational development and creation of the Mexican Virtual Solar Observatory (MVSO) are presented. Basically, the MVSO prototype consists of two parts: the first, related to observations that have been made during the past ten years at the Solar Observation Station (EOS) and at the Carl Sagan Observatory (OCS) of the Universidad de Sonora in Mexico. The second part is associated to the creation and manipulation of a database produced by numerical simulations related to solar phenomena, we are using the MHD ZEUS-3D code. The development of this prototype was made using mysql, apache, java and VSO 1.2. based GNU and `open source philosophy'. A graphic user interface (GUI) was created in order to make web-based, remote numerical simulations. For this purpose, Mono was used, because it is provides the necessary software to develop and run .NET client and server applications on Linux. Although this project is still under development, we hope to have access, by means of this portal, to other virtual solar observatories and to be able to count on a database created through numerical simulations or, given the case, perform simulations associated to solar phenomena.

  1. The National Solar Observatory Digital Library

    Science.gov (United States)

    Hill, F.; Branston, D.; Erdwurm, W.

    1997-05-01

    NSO provides several important data sets to the solar physics community, such as full-disk daily magnetograms, He 10380 spectroheliograms, and solar spectral atlases from Kitt Peak; as well as H-alpha and Ca K spectroheliograms, and coronal scans from Sacramento Peak. The usage of these data sets has rapidly increased over the last 3 years as indicated in the logs of NSO/KP anonymous FTP activity which show increases of 400% in the number of logins, and 100% in the number of files transferred. In order to provide better access to these data for the solar physics community, NSO is developing a digital library. A robotic jukebox that holds 300 CD ROMs (about 210 GB) on-line has been installed at NSO, and the migration of data into this system is substantially underway. At the present time, the entire set of spectra from the Fourier Transform Spectrometer is on-line, as well as about 15% of the Kitt Peak magnetograms and He 10830 images. The Sacramento Peak H-alpha and Ca K spectroheliograms are now being digitized and transferred to CDs. A web-based user interface and search tool is also in development. Oracle has been selected and installed as the RDBMS search engine. Software to populate the database tables using FITS header parameters has been developed. Issues of file name conventions, user request tracking, and download strategies are under study. We expect to have a simple prototype interface and search tool for the Kitt Peak magnetograms available for testing by the user community by Summer 1997. This will provide a foundation that can be easily extended to include additional data sets.

  2. The Virtual Solar Observatory at Eight and a Bit!

    Science.gov (United States)

    Davey, Alisdair R.; VSO Team

    2011-05-01

    The Virtual Solar Observatory (VSO) was the first virtual observatory in the solar and heliophysics data space. It first saw the light of day in 2003 with a mission to serve the solar physics community by enabling homogenous access to heterogeneous data, and hiding the gory details of doing so from the user. The VSO pioneered what was to become the "Small Box" methodology, setting out to provide only the services required to navigate the user to the data and then letting them directly transferred the data from the data providers. After eight and a bit years the VSO now serves data from 72 different instruments covering a multitude of space and ground based observatories, including data from SDO. Dealing with the volume of data from SDO has proved to be our most difficult challenge, forcing us from the small box approach to one where the various VSO sites not only serve SDO data, but are central to the distribution of the data within the US and to Europe and other parts of the world. With SDO data serving mostly in place we are now working on integration with the Heliophysics Event Knowledgebase (HEK) and including a number of new solar data sets in the VSO family. We have a complete VSO search interface in IDL now, enabling searching, downloading and processing solar data, all be done without leaving the IDL command line, and will be releasing a brand new web interface providing users and data providers, with the ability to create far more detailed and instrument specific searches. Eight years on and the VSO has plenty of work in front of it.

  3. Calibration of Solar Radio Spectrometer of the Purple Mountain Observatory

    Science.gov (United States)

    Lei, LU; Si-ming, LIU; Qi-wu, SONG; Zong-jun, NING

    2015-10-01

    Calibration is a basic and important job in solar radio spectral observations. It not only deduces the solar radio flux as an important physical quantity for solar observations, but also deducts the flat field of the radio spectrometer to display the radio spectrogram clearly. In this paper, we first introduce the basic method of calibration based on the data of the solar radio spectrometer of Purple Mountain Observatory. We then analyze the variation of the calibration coefficients, and give the calibrated results for a few flares. These results are compared with those of the Nobeyama solar radio polarimeter and the hard X-ray observations of the RHESSI (Reuven Ramaty High Energy Solar Spectroscopic Imager) satellite, it is shown that these results are consistent with the characteristics of typical solar flare light curves. In particular, the analysis on the correlation between the variation of radio flux and the variation of hard X-ray flux in the pulsing phase of a flare indicates that these observations can be used to study the relevant radiation mechanism, as well as the related energy release and particle acceleration processes.

  4. The Virtual Solar Observatory: Still a Small Box

    Science.gov (United States)

    Gurman, J. B.; Bogart, R. S.; Davey, A. R.; Dimitoglou, G.; Hill, F.; Hourcle, J. A.; Martens, P. C.; Surez-Sola, I.; Tian, K. Q.; Wampler, S.

    2005-01-01

    Two and a half years after a design study began, and a year and a half after development commenced, version 1.0 of the Virtual Solar Observatory (VSO) was released at the 2004 Fall AGU meeting. Although internal elements of the VSO have changed, the basic design has remained the same, reflecting the team's belief in the importance of a simple, robust mechanism for registering data provider holdings, initiating queries at the appropriate provider sites, aggregating the responses, allowing the user to iterate before making a final selection, and enabling the delivery of data directly from the providers. In order to make the VSO transparent, lightweight, and portable, the developers employed XML for the registry, SOAP for communication between a VSO instance and data services, and HTML for the graphic user interface (GUI's). We discuss the internal data model, the API, and user responses to various trial GUI's as typical design issues for any virtual observatory. We also discuss the role of the "small box" of data search, identification, and delivery services provided by the VSO in the larger, Sun-Solar System Connection virtual observatory (VxO) scheme.

  5. The Virtual Solar Observatory: What Are We Up To Now?

    Science.gov (United States)

    Gurman, J. B.; Hill, F.; Suarez-Sola, F.; Bogart, R.; Amezcua, A.; Martens, P.; Hourcle, J.; Hughitt, K.; Davey, A.

    2012-01-01

    In the nearly ten years of a functional Virtual Solar Observatory (VSO), http://virtualsolar.org/ we have made it possible to query and access sixty-seven distinct solar data products and several event lists from nine spacecraft and fifteen observatories or observing networks. We have used existing VSO technology, and developed new software, for a distributed network of sites caching and serving SDO HMI and/ or AlA data. We have also developed an application programming interface (API) that has enabled VSO search and data access capabilities in IDL, Python, and Java. We also have quite a bit of work yet to do, including completion of the implementation of access to SDO EVE data, and access to some nineteen other data sets from space- and ground-based observatories. In addition, we have been developing a new graphic user interface that will enable the saving of user interface and search preferences. We solicit advice from the community input prioritizing our task list, and adding to it

  6. First ten years of Hinode solar on-orbit observatory

    CERN Document Server

    Imada, Shinsuke; Kubo, Masahito

    2018-01-01

    This book provides the latest scientific understanding of the Sun, sharing insights gleaned from the international solar physics project Hinode. The authors (who are the main project contributors) review, from the various viewpoints, the discoveries and advances made by the on-orbit operations of the Hinode spacecraft in its first decade. Further, they present a wealth of scientifically important photographs and data from Hinode. Launched in September 2006, Hinode is the third Japanese solar observatory on orbit, and employs three highly advanced telescopes jointly developed and operated with international partners. The book describes the background of these research topics, how the Hinode telescopes have tackled various challenges, and the scientific achievements and impacts in the first 10 years. Furthermore, it explores future perspective of researches in Japan. The book will benefit undergraduate students interested in recent advance in the solar research, as well as graduate students and researchers work...

  7. Still Virtual After All These Years: Recent Developments in the Virtual Solar Observatory

    Science.gov (United States)

    Gurman, J. B.; Bogart, R. S.; Davey, A. R.; Hill, F.; Martens, P. C.; Zarro, D. M.; Team, T. v.

    2008-05-01

    While continuing to add access to data from new missions, including Hinode and STEREO, the Virtual Solar Observatory is also being enhanced as a research tool by the addition of new features such as the unified representation of catalogs and event lists (to allow joined searches in two or more catalogs) and workable representation and manipulation of large numbers of search results (as are expected from the Solar Dynamics Observatory database). Working with our RHESSI colleagues, we have also been able to improve the performance of IDL-callable vso_search and vso_get functions, to the point that use of those routines is a practical alternative to reproducing large subsets of mission data on one's own LAN.

  8. Still Virtual After All These Years: Recent Developments in the Virtual Solar Observatory

    Science.gov (United States)

    Gurman, Joseph B.; Bogart; Davey; Hill; Masters; Zarro

    2008-01-01

    While continuing to add access to data from new missions, including Hinode and STEREO, the Virtual Solar Observatory is also being enhanced as a research tool by the addition of new features such as the unified representation of catalogs and event lists (to allow joined searches in two or more catalogs) and workable representation and manipulation of large numbers of search results (as are expected from the Solar Dynamics Observatory database). Working with our RHESSI colleagues, we have also been able to improve the performance of IDL-callable vso_search and vso_get functions, to the point that use of those routines is a practical alternative to reproducing large subsets of mission data on one's own LAN.

  9. Adaptive optics system for the IRSOL solar observatory

    Science.gov (United States)

    Ramelli, Renzo; Bucher, Roberto; Rossini, Leopoldo; Bianda, Michele; Balemi, Silvano

    2010-07-01

    We present a low cost adaptive optics system developed for the solar observatory at Istituto Ricerche Solari Locarno (IRSOL), Switzerland. The Shack-Hartmann Wavefront Sensor is based on a Dalsa CCD camera with 256 pixels × 256 pixels working at 1kHz. The wavefront compensation is obtained by a deformable mirror with 37 actuators and a Tip-Tilt mirror. A real time control software has been developed on a RTAI-Linux PC. Scicos/Scilab based software has been realized for an online analysis of the system behavior. The software is completely open source.

  10. Solar activity monitoring and forecasting capabilities at Big Bear Solar Observatory

    Directory of Open Access Journals (Sweden)

    P. T. Gallagher

    2002-07-01

    Full Text Available The availability of full-disk, high-resolution Ha images from Big Bear Solar Observatory (USA, Kanzelhöhe Solar Observatory (Austria, and Yunnan Astronomical Observatory (China allows for the continual monitoring of solar activity with unprecedented spatial and temporal resolution. Typically, this Global Ha Network (GHN provides almost uninterrupted Ha images with a cadence of 1 min and an image scale of 1'' per pixel.  Every hour, GHN images are transferred to the web-based BBSO Active Region Monitor (ARM; www.bbso.njit.edu/arm, which includes the most recent EUV, continuum, and magnetogram data from the Solar and Heliospheric Observatory, together with magnetograms from the Global Oscillation Network Group. ARM also includes a variety of active region properties from the National Oceanic and Atmospheric Administration’s Space Environment Center, such as up-to-date active region positions, GOES 5-min X-ray data, and flare identification. Stokes I, V, Q, and U images are available from the recently operational BBSO Digital Vector Magnetograph and the Vector Magnetograph at the Huairou Solar Observing Station of Beijing Observatory. Vector magnetograms provide complete information on the photospheric magnetic field, and allow for magnetic flux gradients, electric currents, and shear forces to be calculated: these measurements are extremely sensitive to conditions resulting in flaring activity. Furthermore, we have developed a Flare Prediction System which estimates the probability for each region to produce C-, M-, or X-class flares based on nearly eight years of NOAA data from cycle 22. This, in addition to BBSO’s daily solar activity reports, has proven a useful resource for activity forecasting.Key words. Solar physics, astronomy and astrophysics (flares and mass ejections; instruments and techniques; photosphere and chromosphere

  11. Automated Temperature and Emission Measure Analysis of Coronal Loops and Active Regions Observed with the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO/AIA)

    Science.gov (United States)

    Aschwanden, Markus J.; Boerner, Paul; Schrijver, Carolus J.; Malanushenko, Anna

    2013-03-01

    We developed numerical codes designed for automated analysis of SDO/AIA image datasets in the six coronal filters, including: i) coalignment test between different wavelengths with measurements of the altitude of the EUV-absorbing chromosphere, ii) self-calibration by empirical correction of instrumental response functions, iii) automated generation of differential emission measure [DEM] distributions with peak-temperature maps [ T p( x, y)] and emission measure maps [ EM p( x, y)] of the full Sun or active region areas, iv) composite DEM distributions [d EM( T)/d T] of active regions or subareas, v) automated detection of coronal loops, and vi) automated background subtraction and thermal analysis of coronal loops, which yields statistics of loop temperatures [ T e], temperature widths [ σ T], emission measures [ EM], electron densities [ n e], and loop widths [ w]. The combination of these numerical codes allows for automated and objective processing of numerous coronal loops. As an example, we present the results of an application to the active region NOAA 11158, observed on 15 February 2011, shortly before it produced the largest (X2.2) flare during the current solar cycle. We detect 570 loop segments at temperatures in the entire range of log( T e)=5.7 - 7.0 K and corroborate previous TRACE and AIA results on their near-isothermality and the validity of the Rosner-Tucker-Vaiana (RTV) law at soft X-ray temperatures ( T≳2 MK) and its failure at lower EUV temperatures.

  12. Solar atmosphere wave dynamics generated by solar global oscillating eigenmodes

    Science.gov (United States)

    Griffiths, M. K.; Fedun, V.; Erdélyi, R.; Zheng, R.

    2018-01-01

    The solar atmosphere exhibits a diverse range of wave phenomena, where one of the earliest discovered was the five-minute global acoustic oscillation, also referred to as the p-mode. The analysis of wave propagation in the solar atmosphere may be used as a diagnostic tool to estimate accurately the physical characteristics of the Sun's atmospheric layers. In this paper, we investigate the dynamics and upward propagation of waves which are generated by the solar global eigenmodes. We report on a series of hydrodynamic simulations of a realistically stratified model of the solar atmosphere representing its lower region from the photosphere to low corona. With the objective of modelling atmospheric perturbations, propagating from the photosphere into the chromosphere, transition region and low corona, generated by the photospheric global oscillations the simulations use photospheric drivers mimicking the solar p-modes. The drivers are spatially structured harmonics across the computational box parallel to the solar surface. The drivers perturb the atmosphere at 0.5 Mm above the bottom boundary of the model and are placed coincident with the location of the temperature minimum. A combination of the VALIIIC and McWhirter solar atmospheres are used as the background equilibrium model. We report how synthetic photospheric oscillations may manifest in a magnetic field free model of the quiet Sun. To carry out the simulations, we employed the magnetohydrodynamics code, SMAUG (Sheffield MHD Accelerated Using GPUs). Our results show that the amount of energy propagating into the solar atmosphere is consistent with a model of solar global oscillations described by Taroyan and Erdélyi (2008) using the Klein-Gordon equation. The computed results indicate a power law which is compared to observations reported by Ireland et al. (2015) using data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly.

  13. Solar System Dynamics

    Science.gov (United States)

    Wisdom, Jack

    2002-01-01

    In these 18 years, the research has touched every major dynamical problem in the solar system, including: the effect of chaotic zones on the distribution of asteroids, the delivery of meteorites along chaotic pathways, the chaotic motion of Pluto, the chaotic motion of the outer planets and that of the whole solar system, the delivery of short period comets from the Kuiper belt, the tidal evolution of the Uranian arid Galilean satellites, the chaotic tumbling of Hyperion and other irregular satellites, the large chaotic variations of the obliquity of Mars, the evolution of the Earth-Moon system, and the resonant core- mantle dynamics of Earth and Venus. It has introduced new analytical and numerical tools that are in widespread use. Today, nearly every long-term integration of our solar system, its subsystems, and other solar systems uses algorithms that was invented. This research has all been primarily Supported by this sequence of PGG NASA grants. During this period published major investigations of tidal evolution of the Earth-Moon system and of the passage of the Earth and Venus through non-linear core-mantle resonances were completed. It has published a major innovation in symplectic algorithms: the symplectic corrector. A paper was completed on non-perturbative hydrostatic equilibrium.

  14. The Geospace Dynamics Observatory; a mission of discovery for Geospace

    Science.gov (United States)

    Spann, J. F.; Paxton, L.; Burch, J. L.; Reardon, P.; Habash Krause, L.; Gallagher, D. L.; Hopkins, R.

    2013-12-01

    Geospace Dynamics Observatory (GDO) takes advantage a repurposed optical system to provide new, unique, and cost-effective insights into the dynamics of geospace. New missions investigating the ITM system and the magnetospheric-ionospheric coupling processes have generally been very focused on specific phenomena, generally limited by the resource constraints and mission size. Exploring options for observing these regions with instrumentation that is 'non-traditional' is not often considered. The possibility of using very large optics to image Geospace has recently come to the fore. This talk will address the science that would be enabled by flying an ultraviolet telescope imaging the ITM region with an aperture greater than 2 meters. A brief overview of the use of this asset in a science-driven mission concept called the Geospace Dynamics Observatory (GDO) will be presented. This talk will explore the optical and technical aspects of the GDO mission and the implementation strategy. Additionally, the case will be made that GDO will address a significant portion of the priority mission science articulated in the recent Solar and Space Physics Decadal Survey, and provide unprecedented discovery opportunities. One of the problems common to all of geospace research is that of resolving temporal and spatial ambiguities: are the observed changes due the fact that the location of the observation has changed or have the state variables changed? This is a particularly vexing problem for low-cost missions that may have to rely on in situ measurements or other low spatial resolution techniques such as GPS radio occultation. The exceptional capabilities of the GDO mission include (1) unprecedented improvement in signal to noise for global-scale imaging of Earth's space environment that enables changes in the Earth's space environment to be resolved with orders of magnitude higher temporal and spatial resolution compared to existing data and other approaches, and (2) unrivaled

  15. Gamma ray observatory dynamics simulator in Ada (GRODY)

    International Nuclear Information System (INIS)

    1990-09-01

    This experiment involved the parallel development of dynamics simulators for the Gamma Ray Observatory in both FORTRAN and Ada for the purpose of evaluating the applicability of Ada to the NASA/Goddard Space Flight Center's flight dynamics environment. The experiment successfully demonstrated that Ada is a viable, valuable technology for use in this environment. In addition to building a simulator, the Ada team evaluated training approaches, developed an Ada methodology appropriate to the flight dynamics environment, and established a baseline for evaluating future Ada projects

  16. Preliminary trajectory design for a solar polar observatory using SEP and multiple gravity assists

    NARCIS (Netherlands)

    Corpaccioli, L.; Noomen, R.; De Smet, S.; Parker, J.S.; Herman, J.F.C.

    2015-01-01

    Satellite solar observatories have always been of central importance to heliophysics; while there have been numerous such missions, the solar poles have been extremely under-observed. This paper proposes to use low-thrust as well as multiple gravity assists to reach the enormous energies required

  17. Lockheed Solar Observatory and the Discovery of Moreton-Ramsey Waves

    Science.gov (United States)

    Tarbell, Theodore D.

    2014-06-01

    Moreton Waves are high-speed disturbances seen traveling away from large solar flares in H-alpha movies of the solar chromosphere. They were discovered by the observer Harry Ramsey in the late 1950s, and then published and publicized by the director Gail Moreton, both of the Lockheed Solar Observatory in the Hollywood Hills of Southern California. These efforts established the scientific reputation and secured continuing funding of the observatory, whose present-day successor is the Lockheed Martin Solar and Astrophysics Lab in Palo Alto. Moreton waves are rare, and there was limited interest in them until the EIT instrument on SOHO began seeing large numbers of similar waves in the corona in the late 1990s. The exact relation between the two observations is still a research topic today. This talk will describe some of the history of the observatory and the discovery and early interpretation of the waves.

  18. A Dedicated Space Observatory For Time-domain Solar System Science

    Science.gov (United States)

    Wong, Michael H.; Ádámkovics, M.; Benecchi, S.; Bjoraker, G.; Clarke, J. T.; de Pater, I.; Hendrix, A. R.; Marchis, F.; McGrath, M.; Noll, K.; Rages, K. A.; Retherford, K.; Smith, E. H.; Strange, N. J.

    2009-09-01

    Time-variable phenomena with scales ranging from minutes to decades have led to a large fraction of recent advances in many aspects of solar system science. We present the scientific motivation for a dedicated space observatory for solar system science. This facility will ideally conduct repeated imaging and spectroscopic observations over a period of 10 years or more. It will execute a selection of long-term projects with interleaved scheduling, resulting in the acquisition of data sets with consistent calibration, long baselines, and optimized sampling intervals. A sparse aperture telescope would be an ideal configuration for the mission, trading decreased sensitivity for reduced payload mass, while preserving spatial resolution. Ultraviolet capability is essential, especially once the Hubble Space Telescope retires. Specific investigations will include volcanism and cryovolcanism (on targets including Io, Titan, Venus, Mars, and Enceladus); zonal flow, vortices, and storm evolution on the giant planets; seasonal cycles in planetary atmospheres; mutual events and orbit determination of multiple small solar system bodies; auroral activity and solar wind interactions; and cometary evolution. The mission will produce a wealth of data products--such as multi-year time-lapse movies of planetary atmospheres--with significant education and public outreach potential. Existing and planned ground- and space-based facilities are not suitable for these time-domain optimized planetary dynamics studies for numerous reasons, including: oversubscription by astrophysical users, field-of-regard limitations, sensitive detector saturation limits that preclude bright planetary targets, and limited mission duration. The abstract author list is a preliminary group of scientists who have shown interest in prior presentations on this topic; interested parties may contact the lead author by 1 September to sign the associated Planetary Science Decadal Survey white paper or by 1 October to

  19. Solar Hα and white light telescope at Hvar Observatory

    Czech Academy of Sciences Publication Activity Database

    Čalogovic, J.; Dumbovic, M.; Novak, S.; Vršnak, B.; Brajša, R.; Pötzi, W.; Hirtenfellner-Polanec, W.; Veronig, A.; Hanslmeier, A.; Klvaňa, Miroslav; Ambrož, Pavel

    2012-01-01

    Roč. 36, č. 2012 (2012), s. 83-88 ISSN 1845-8319 Institutional support: RVO:67985815 Keywords : solar observations * telescope * photosphere Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  20. The Solar Physics Observatory at Kodaikanal and John Evershed

    Indian Academy of Sciences (India)

    Admin

    principal institutions devoted to work on the fundamental posi- .... All major astronomical equipment and the library were shifted from Madras to Kodaikanal .... eclipses, Evershed carried his own home-made instruments, prismatic ... scientifically fruitful time organised by Hale's main solar collaborator Ellerman and the staff of.

  1. Education and public outreach at the Carl Sagan Solar Observatory of the University of Sonora

    Directory of Open Access Journals (Sweden)

    Julio Saucedo-Morales

    2013-05-01

    Full Text Available We discuss the importance of small solar observatories for EPO (Education and Public Outreach, mentioning why they are relevant and what kind of equipment and software require. We stress the fact that technological advances have made them affordable and that they should be widely available. This work is a result of our experience with one: The Carl Sagan Solar Observatory (CSSO. We briefly describe its status and the solar data obtained daily with students participation. We present examples of the data obtained in the visible, Ca II and two in Hα. Data which is widely used for education. Finally we talk about the capability for remote operation as an open invitation for collaboration in educational and scientific projects.

  2. Education and public outreach at the Carl Sagan Solar Observatory of the University of Sonora

    Science.gov (United States)

    Saucedo-Morales Julio; Loera-González, Pablo

    2013-05-01

    We discuss the importance of small solar observatories for EPO (Education and Public Outreach), mentioning why they are relevant and what kind of equipment and software require. We stress the fact that technological advances have made them affordable and that they should be widely available. This work is a result of our experience with one: The Carl Sagan Solar Observatory (CSSO). We briefly describe its status and the solar data obtained daily with students participation. We present examples of the data obtained in the visible, Ca II and two in Hα. Data which is widely used for education. Finally we talk about the capability for remote operation as an open invitation for collaboration in educational and scientific projects.

  3. Solar array flight dynamic experiment

    Science.gov (United States)

    Schock, Richard W.

    1987-01-01

    The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures' dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-41D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

  4. Observatory of photovoltaic solar energy in France - 20. edition

    International Nuclear Information System (INIS)

    2016-12-01

    After an overview of important events in the World regarding the development of photovoltaic solar energy in 2016, and predictions regarding new connected installations in 2016, this document present graphs and figures which illustrate the evolution of the photovoltaic fleet in the World, the comparison of production costs of new electric power generation capacities, the evolution of the French photovoltaic power production since 2009, the evolution of the distribution of the French fleet in terms of installation power (from large projects to residential), of connections to the grid, of number of connections and purchase tariffs for the different types of installations (residential, medium roofs, large roofs, very large roofs, very large ground-based or roof-based projects) and for queuing projects, in terms of evolution of purchase tariffs since 2011, and of evolution of impact on the CSPE financing system

  5. Earth-Affecting Solar Causes Observatory (EASCO): a mission at the Sun-Earth L5

    DEFF Research Database (Denmark)

    Gopalswamy, Nat; Davila, Joseph M.; Auchère, Frédéric

    2011-01-01

    Observatory (STEREO) missions, but these missions lacked some key measurements: STEREO did not have a magnetograph; SOHO did not have in-situ magnetometer. SOHO and other imagers such as the Solar Mass Ejection Imager (SMEI) located on the Sun-Earth line are also not well-suited to measure Earth-directed CMEs....... The Earth-Affecting Solar Causes Observatory (EASCO) is a proposed mission to be located at the Sun-Earth L5 that overcomes these deficiencies. The mission concept was recently studied at the Mission Design Laboratory (MDL), NASA Goddard Space Flight Center, to see how the mission can be implemented....... The study found that the scientific payload (seven remote-sensing and three in-situ instruments) can be readily accommodated and can be launched using an intermediate size vehicle; a hybrid propulsion system consisting of a Xenon ion thruster and hydrazine has been found to be adequate to place the payload...

  6. The stellar and solar tracking system of the Geneva Observatory gondola

    Science.gov (United States)

    Huguenin, D.

    1974-01-01

    Sun and star trackers have been added to the latest version of the Geneva Observatory gondola. They perform an image motion compensation with an accuracy of plus or minus 1 minute of arc. The structure is held in the vertical position by gravity; the azimuth is controlled by a torque motor in the suspension bearing using solar or geomagnetic references. The image motion compensation is performed by a flat mirror, located in front of the telescope, controlled by pitch and yaw servo-loops. Offset pointing is possible within the solar disc and in a 3 degree by 3 degree stellar field. A T.V. camera facilitates the star identification and acquisition.

  7. The Baksan Neutrino Observatory Soviet-American Gallium Solar Neutrino Experiment

    International Nuclear Information System (INIS)

    Abazov, A.I.; Abdurashitov, D.N.; Anosov, O.V.

    1988-01-01

    A radiochemical 71 Ga- 71 Ge experiment to determine the integral flux of neutrinos from the sun is currently under preparation at the Baksan Neutrino Observatory in the USSR. Measurements are scheduled to commence by late 1988 with 30 tonnes of metallic gallium. A fractional statistical accuracy of 18% is expected to be obtained after one year of operation if the solar signal obtained after one year of operation if the solar signal is 70 SNU, the flux expected from p-p neutrinos alone. While initial measurements are in progress, 30 additional tonnes of gallium will be installed in order to perform the full experiment with a 60-tonne target. 28 refs

  8. Sunwatchers Across Time: Sun-Earth Day from Ancient and Modern Solar Observatories

    Science.gov (United States)

    Hawkins, I.; Vondrak, R.

    Humans across all cultures have venerated, observed, and studied the Sun for thousands of years. The Sun, our nearest star, provides heat and energy, is the cause of the seasons, and causes space weather effects that influence our technology-dependent society. The Sun is also part of indigenous tradition and culture. The Inca believed that the Sun had the power to make things grow, and it does, providing us with the heat and energy that are essential to our survival. From a NASA perspective, Sun-Earth Connection research investigates the effects of our active Sun on the Earth and other planets, namely, the interaction of the solar wind and other dynamic space weather phenomena with the solar system. We present plans for Sun-Earth Day 2005, a yearly celebration of the Sun-Earth Connection sponsored by the NASA Sun-Earth Connection Education Forum (SECEF). SECEF is one of four national centers of space science education and public outreach funded by NASA Office of Space Science. Sun-Earth Day involves an international audience of schools, science museums, and the general public in activities and events related to learning about the Sun-Earth Connection. During the year 2005, the program will highlight cultural and historical perspectives, as well as NASA science, through educational and public outreach events intended to involve diverse communities. Sun-Earth Day 2005 will include a series of webcasts from solar observatories produced by SECEF in partnership with the San Francisco Exploratorium. Webcasts from Chaco Culture National Historical Park in New Mexico, USA, and from Chichen Itza, Mexico, will be accessed by schools and the public. Sun-Earth Day will also feature NASA Sun-Earth Connection research, missions, and the people who make it possible. One of the goals of this talk is to inform and engage COSPAR participants in these upcoming public events sponsored by NASA. Another goal is to share best practices in public event programming, and present impact

  9. GRODY - GAMMA RAY OBSERVATORY DYNAMICS SIMULATOR IN ADA

    Science.gov (United States)

    Stark, M.

    1994-01-01

    Analysts use a dynamics simulator to test the attitude control system algorithms used by a satellite. The simulator must simulate the hardware, dynamics, and environment of the particular spacecraft and provide user services which enable the analyst to conduct experiments. Researchers at Goddard's Flight Dynamics Division developed GRODY alongside GROSS (GSC-13147), a FORTRAN simulator which performs the same functions, in a case study to assess the feasibility and effectiveness of the Ada programming language for flight dynamics software development. They used popular object-oriented design techniques to link the simulator's design with its function. GRODY is designed for analysts familiar with spacecraft attitude analysis. The program supports maneuver planning as well as analytical testing and evaluation of the attitude determination and control system used on board the Gamma Ray Observatory (GRO) satellite. GRODY simulates the GRO on-board computer and Control Processor Electronics. The analyst/user sets up and controls the simulation. GRODY allows the analyst to check and update parameter values and ground commands, obtain simulation status displays, interrupt the simulation, analyze previous runs, and obtain printed output of simulation runs. The video terminal screen display allows visibility of command sequences, full-screen display and modification of parameters using input fields, and verification of all input data. Data input available for modification includes alignment and performance parameters for all attitude hardware, simulation control parameters which determine simulation scheduling and simulator output, initial conditions, and on-board computer commands. GRODY generates eight types of output: simulation results data set, analysis report, parameter report, simulation report, status display, plots, diagnostic output (which helps the user trace any problems that have occurred during a simulation), and a permanent log of all runs and errors. The

  10. A Space Weather mission concept: Observatories of the Solar Corona and Active Regions (OSCAR)

    DEFF Research Database (Denmark)

    Strugarek, Antoine; Janitzek, Nils; Lee, Arrow

    2015-01-01

    advancements in the field of solar physics, improvements of the current CME prediction models, and provide data for reliable space weather forecasting. These objectives are achieved by utilising two spacecraft with identical instrumentation, located at a heliocentric orbital distance of 1 AU from the Sun......Coronal Mass Ejections (CMEs) and Corotating Interaction Regions (CIRs) are major sources of magnetic storms on Earth and are therefore considered to be the most dangerous space weather events. The Observatories of Solar Corona and Active Regions (OSCAR) mission is designed to identify the 3D...... structure of coronal loops and to study the trigger mechanisms of CMEs in solar Active Regions (ARs) as well as their evolution and propagation processes in the inner heliosphere. It also aims to provide monitoring and forecasting of geo-effective CMEs and CIRs. OSCAR would contribute to significant...

  11. Structure and dynamics of the solar chromosphere

    NARCIS (Netherlands)

    Krijger, Johannes Mattheus

    2002-01-01

    The thesis "Structure and dynamics of the solar chromosphere" of J.M. Krijger is a study on the behavior of the solar chromosphere, the thin layer just above the solar surface (photosphere) visible in purple red light during a total solar eclipse. The most important result of this thesis is that the

  12. Solar dynamic power module design

    Science.gov (United States)

    Secunde, Richard R.; Labus, Thomas L.; Lovely, Ronald G.

    1989-01-01

    Studies have shown that the use of solar dynamic (SD) power for the growth areas of the Space Station Freedom program will result in life cycle cost savings when compared to power supplied by photovoltaic sources. In the SD power module, a concentrator collects and focuses solar energy into a heat receiver which has integral thermal energy storage. A Power Conversion Unit (PCU) based on the closed Brayton cycle removes thermal energy from the receiver and converts that energy to electrical energy. Since the closed Brayton cycle is a single phase gas cycle, the conversion hardware (heat exchangers, turbine, compressor, etc.) can be designed for operation in low earth orbit, and tested with confidence in test facilities on earth before launch into space. The concentrator subassemblies will be aligned and the receiver/PCU/radiator combination completely assembled and charged with gas and cooling liquid on earth before launch to, and assembly on, orbit.

  13. Extra Solar Planetary Imaging Coronagraph and Science Requirements for the James Webb Telescope Observatory

    Science.gov (United States)

    Clampin, Mark

    2004-01-01

    1) Extra solar planetary imaging coronagraph. Direct detection and characterization of Jovian planets, and other gas giants, in orbit around nearby stars is a necessary precursor to Terrestrial Planet Finder 0 in order to estimate the probability of Terrestrial planets in our stellar neighborhood. Ground based indirect methods are biased towards large close in Jovian planets in solar systems unlikely io harbor Earthlike planets. Thus to estimate the relative abundances of terrestrial planets and to determine optimal observing strategies for TPF a pathfinder mission would be desired. The Extra-Solar Planetary Imaging Coronagraph (EPIC) is such a pathfinder mission. Upto 83 stellar systems are accessible with a 1.5 meter unobscured telescope and coronagraph combination located at the Earth-Sun L2 point. Incorporating radiometric and angular resolution considerations show that Jovians could be directly detected (5 sigma) in the 0.5 - 1.0 micron band outside of an inner working distance of 5/D with integration times of -10 - 100 hours per observation. The primary considerations for a planet imager are optical wavefront quality due to manufacturing, alignment, structural and thermal considerations. pointing stability and control, and manufacturability of coronagraphic masks and stops to increase the planetary-to- stellar contrast and mitigate against straylight. Previously proposed coronagraphic concepts are driven to extreme tolerances. however. we have developed and studied a mission, telescope and coronagraphic detection concept, which is achievable in the time frame of a Discovery class NASA mission. 2) Science requirements for the James Webb Space Telescope observatory. The James Webb Space Observatory (JWST) is an infrared observatory, which will be launched in 201 1 to an orbit at L2. JWST is a segmented, 18 mirror segment telescope with a diameter of 6.5 meters, and a clear aperture of 25 mA2. The telescope is designed to conduct imaging and spectroscopic

  14. X-ray observations of solar flares with the Einstein Observatory

    International Nuclear Information System (INIS)

    Schmitt, J.H.M.M.; Fink, H.; Harnden, F.R. Jr.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

    1987-01-01

    The first Einstein Observatory Imaging Proportional Counter (IPC) observations of solar flares are presented. These flares were detected in scattered X-ray light when the X-ray telescope was pointed at the sunlit earth. The propagation and scattering of solar X-rays in the earth's atmosphere are discussed in order to be able to deduce the solar X-ray flux incident on top of the atmosphere from scattered X-ray intensity measurements. After this correction, the scattered X-ray data are interpreted as full-disk observations of the sun obtained with the same instrumentation used for observations of flares on other stars. Employing the same data analysis and interpretation techniques, extremely good agreement is found between the physical flare parameters deduced from IPC observations and known properties of compact loop flares. This agreement demonstrates that flare observations with the IPC can reveal physical parameters such as temperature and density quite accurately in the solar case and therefore suggests that the interpretations of stellar X-ray flare observations are on a physically sound basis. 26 references

  15. The Origin and Dynamics of Solar Magnetism

    CERN Document Server

    Thompson, M. J; Culhane, J. L; Nordlund, Å; Solanki, S. K; Zahn, J.-P

    2009-01-01

    The articles collected in this volume present all aspects of solar magnetism: from its origin in the solar dynamo to its evolution and dynamics that create the variability of solar phenomena, its well-known 11-year activity cycle that leads to the ever-changing pattern of sunspots and active regions on the Sun. Several contributions deal with the solar dynamo, the driver of many solar phenomena. Other contributions treat the transport and emergence of the magnetic flux through the outer layers of the Sun. The coupling of magnetic fields from the surface to the solar corona and beyond is also described, together with current studies on the predictability of solar activity. This book is aimed at researchers and graduate students working in solar physics and space science. It provides a full review of our current understanding of solar magnetism by the foremost experts in the field.

  16. COR1 Engineering Test Unit Measurements at the Mauna Loa Solar Observatory, September 2003

    Science.gov (United States)

    Thompson, William; Reginald, Nelson; Streander, Kim

    2003-01-01

    The COR1 Engineering Test Unit (ETU), which had been previously tested at the NCAR/HAO and NRL test facilities, was modified into an instrument capable of observing the Sun. It was then taken to the Mauna Loa Solar Observatory to observe the corona. The changes made to observe the Sun were as follows: 1. The plate scale was changed to accommodate the smaller Apogee camera. This change had already been made for the NRL tests. 2. The previous Oriel polarizer was replaced with a commercial Polarcor polarizer from Newport to be more flight-like. However, because of cost and availability considerations, this polarizer was smaller than those which will be used for flight. 3. A structure was placed around the back section of the instrument, to protect it from stray light. 4. A pointing spar borrowed from HAO was used to track the Sun. A few days into the test, it became evident that some artifacts were appearing in the data, and these artifacts were changing as the polarizer was rotated. It was decided to test two other polarizers, the Oriel polarizer which had been used in the previous tests at HAO and NRL, and a Nikon polarizer which was borrowed from a camera belonging to one of the observatory staff members. These three polarizers had much different qualities are shown.

  17. Modeling observations of solar coronal mass ejections with heliospheric imagers verified with the Heliophysics System Observatory.

    Science.gov (United States)

    Möstl, C; Isavnin, A; Boakes, P D; Kilpua, E K J; Davies, J A; Harrison, R A; Barnes, D; Krupar, V; Eastwood, J P; Good, S W; Forsyth, R J; Bothmer, V; Reiss, M A; Amerstorfer, T; Winslow, R M; Anderson, B J; Philpott, L C; Rodriguez, L; Rouillard, A P; Gallagher, P; Nieves-Chinchilla, T; Zhang, T L

    2017-07-01

    We present an advance toward accurately predicting the arrivals of coronal mass ejections (CMEs) at the terrestrial planets, including Earth. For the first time, we are able to assess a CME prediction model using data over two thirds of a solar cycle of observations with the Heliophysics System Observatory. We validate modeling results of 1337 CMEs observed with the Solar Terrestrial Relations Observatory (STEREO) heliospheric imagers (HI) (science data) from 8 years of observations by five in situ observing spacecraft. We use the self-similar expansion model for CME fronts assuming 60° longitudinal width, constant speed, and constant propagation direction. With these assumptions we find that 23%-35% of all CMEs that were predicted to hit a certain spacecraft lead to clear in situ signatures, so that for one correct prediction, two to three false alarms would have been issued. In addition, we find that the prediction accuracy does not degrade with the HI longitudinal separation from Earth. Predicted arrival times are on average within 2.6 ± 16.6 h difference of the in situ arrival time, similar to analytical and numerical modeling, and a true skill statistic of 0.21. We also discuss various factors that may improve the accuracy of space weather forecasting using wide-angle heliospheric imager observations. These results form a first-order approximated baseline of the prediction accuracy that is possible with HI and other methods used for data by an operational space weather mission at the Sun-Earth L5 point.

  18. A Simple and Customizable Web Interface to the Virtual Solar Observatory

    Science.gov (United States)

    Hughitt, V. Keith; Hourcle, J.; Suarez-Sola, I.; Davey, A.

    2010-05-01

    As the variety and number of solar data sources continue to increase at a rapid rate, the importance of providing methods to search through these sources becomes increasingly important. By taking advantage of the power of modern JavaScript libraries, a new version of the Virtual Solar Observatory's web interface aims to provide a significantly faster and simpler way to explore the multitude of data repositories available. Querying asynchroniously serves not only to eliminates bottlenecks resulting from slow or unresponsive data providers, but also allows for displaying of results as soon as they are returned. Implicit pagination and post-query filtering enables users to work with large result-sets, while a more modular and customizable UI provides a mechanism for customizing both the look-and-feel and behavior of the VSO web interface. Finally, the new web interface features a custom widget system capable of displaying additional tools and information along-side of the standard VSO search form. Interested users can also write their own widgets and submit them for future incorporation into VSO.

  19. The Descent of the Serpent: Using a Successful Ancient Solar Observatories Webcast from Chichen Itza to Highlight Space Weather Research

    Science.gov (United States)

    Hawkins, I.; Higdon, R.; Cline, T.

    2006-12-01

    Over the past seven years, NASA's Sun-Earth Connection Education Forum has sponsored and coordinated education and public outreach events to highlight NASA's heliophysics research and discoveries. Our strategy involves using celestial events, such as total solar eclipses and the Transit of Venus, as well as Sun-Earth Day during the March Equinox, to engage K-12 schools and the general public in space science activities, demonstrations, and interactions with space scientists. In collaboration with partners that include the Exploratorium and other museums, Ideum, NASA TV, NASA heliophysics missions, and others, we produce webcasts, other multi-media, and print resources for use by school and informal educators nation-wide and internationally. We provide training and professional development to K-12 educators, museum personnel, amateur astronomers, Girl Scout leaders, etc., so they can implement their own outreach programs taking advantage of our resources. A coordinated approach promotes multiple programs occurring each year under a common theme. As part of an Ancient Observatories theme in 2005, we have successfully featured solar alignments with ancient structures made by indigenous cultures that mark the equinoxes and/or solstices in cultural and historical parks in the Americas. In partnership with the Exploratorium, we produced broadcast-quality and webcast programming during the March equinox that shared heliophysics within a broad cultural context with formal and informal education audiences internationally. The program: "Descent of the Serpent" featured the light and shadow effect at sunset that takes place during the spring equinox at the Pyramid of El Castillo, in Chichén Itzá (México). This program made unique and authentic cultural connections to the knowledge of solar astronomy of the Maya, the living Mayan culture of today, and the importance of the Sun across the ages. We involved Sun-Earth Connection scientists, their missions, and research

  20. Solar dynamics influence on the atmospheric ozone

    International Nuclear Information System (INIS)

    Gogosheva, T.; Grigorieva, V.; Mendeva, B.; Krastev, D.; Petkov, B.

    2007-01-01

    A response of the atmospheric ozone to the solar dynamics has been studied using the total ozone content data, taken from the satellite experiments GOME on ERS-2 and TOMS-EP together with data obtained from the ground-based spectrophotometer Photon operating in Stara Zagora, Bulgaria during the period 1999-2005. We also use data from surface ozone observations performed in Sofia, Bulgaria. The solar activity was characterized by the sunspot daily numbers W, the solar radio flux at 10.7 cm (F10.7) and the MgII wing-to-core ratio solar index. The impact of the solar activity on the total ozone has been investigated analysing the ozone response to sharp changes of these parameters. Some of the examined cases showed a positive correlation between the ozone and the solar parameters, however, a negative correlation in other cases was found. There were some cases when the sharp increases of the solar activity did not provoke any ozone changes. The solar radiation changes during an eclipse can be considered a particular case of the solar dynamics as this event causes a sharp change of irradiance within a comparatively short time interval. The results of both - the total and surface ozone measurements carried out during the eclipses on 11 August 1999, 31 May 2003 and 29 March 2006 are presented. It was found that the atmospheric ozone behavior shows strong response to the fast solar radiation changes which take place during solar eclipse. (authors)

  1. Solar thermal - the new dynamics

    International Nuclear Information System (INIS)

    2017-01-01

    This booklet is intended to engineering consultants and construction professionals and aims at showing them the real interest of solar thermal energy. It notably highlights the very high efficiency which can be reached, the high performance value compared to gas, the high rank of solar thermal energy in terms of profitability over a 20-year period, the fact that solar thermal energy is almost always the most economic solution for buildings and the less expensive in comparison with non renewable energies. It outlines that, as far as purchase is concerned, solar thermal energy is more than competitive, is also a leader as far as financing issues are concerned. It finally briefly describes how the SOCOL initiative can be a support at any step of a solar thermal project

  2. Dynamics of the solar system

    International Nuclear Information System (INIS)

    Sidlichovsky, M.

    1987-01-01

    The conference proceedings contains a total of 31 papers of which 7 have not been incorporated in INIS. The papers mainly discuss the mathematical methods of calculating the movement of planets, their satellites and asteroids in the solar system and the mathematical modelling of the past development of the solar system. Great attention is also devoted to resonance in the solar system and to the study of many celestial bodies. Four papers are devoted to planetary rings and three to modern astrometry. (M.D.). 63 figs., 10 tabs., 520 refs

  3. Compatibility of different measurement techniques. Long-term global solar radiation observations at Izaña Observatory [Discussion paper

    OpenAIRE

    García Cabrera, Rosa Delia; Cuevas Agulló, Emilio; García Rodríguez, Omaira Elena; Ramos López, Ramón; Romero Campos, Pedro Miguel; Ory Ajamil, Fernando de; Cachorro, Victoria E.; Frutos, Ángel M. de

    2016-01-01

    A 1-year intercomparison of classical and modern radiation and sunshine duration instruments has been performed at Izaña Atmospheric Observatory. We compare global solar radiation (GSR) records measured with a Kipp & Zonen CM-21 pyranometer, taken in the framework of the Baseline Surface Radiation Network, with those measured with a multifilter rotating shadowband radiometer and a bimetallic pyranometer, and with GSR estimated from sunshine duration performed with a CS sunshine recorder.

  4. Use of Statistical Estimators as Virtual Observatory Search ParametersEnabling Access to Solar and Planetary Resources through the Virtual Observatory

    Science.gov (United States)

    Merka, J.; Dolan, C. F.

    2015-12-01

    Finding and retrieving space physics data is often a complicated taskeven for publicly available data sets: Thousands of relativelysmall and many large data sets are stored in various formats and, inthe better case, accompanied by at least some documentation. VirtualHeliospheric and Magnetospheric Observatories (VHO and VMO) help researches by creating a single point of uniformdiscovery, access, and use of heliospheric (VHO) and magnetospheric(VMO) data.The VMO and VHO functionality relies on metadata expressed using theSPASE data model. This data model is developed by the SPASE WorkingGroup which is currently the only international group supporting globaldata management for Solar and Space Physics. The two Virtual Observatories(VxOs) have initiated and lead a development of a SPASE-related standardnamed SPASE Query Language for provided a standard way of submittingqueries and receiving results.The VMO and VHO use SPASE and SPASEQL for searches based on various criteria such as, for example, spatial location, time of observation, measurement type, parameter values, etc. The parameter values are represented by their statisticalestimators calculated typically over 10-minute intervals: mean, median, standard deviation, minimum, and maximum. The use of statistical estimatorsenables science driven data queries that simplify and shorten the effort tofind where and/or how often the sought phenomenon is observed, as we will present.

  5. Ultrafast Electron Dynamics in Solar Energy Conversion.

    Science.gov (United States)

    Ponseca, Carlito S; Chábera, Pavel; Uhlig, Jens; Persson, Petter; Sundström, Villy

    2017-08-23

    Electrons are the workhorses of solar energy conversion. Conversion of the energy of light to electricity in photovoltaics, or to energy-rich molecules (solar fuel) through photocatalytic processes, invariably starts with photoinduced generation of energy-rich electrons. The harvesting of these electrons in practical devices rests on a series of electron transfer processes whose dynamics and efficiencies determine the function of materials and devices. To capture the energy of a photogenerated electron-hole pair in a solar cell material, charges of opposite sign have to be separated against electrostatic attractions, prevented from recombining and being transported through the active material to electrodes where they can be extracted. In photocatalytic solar fuel production, these electron processes are coupled to chemical reactions leading to storage of the energy of light in chemical bonds. With the focus on the ultrafast time scale, we here discuss the light-induced electron processes underlying the function of several molecular and hybrid materials currently under development for solar energy applications in dye or quantum dot-sensitized solar cells, polymer-fullerene polymer solar cells, organometal halide perovskite solar cells, and finally some photocatalytic systems.

  6. Observatories and Telescopes of Modern Times

    Science.gov (United States)

    Leverington, David

    2016-11-01

    Preface; Part I. Optical Observatories: 1. Palomar Mountain Observatory; 2. The United States Optical Observatory; 3. From the Next Generation Telescope to Gemini and SOAR; 4. Competing primary mirror designs; 5. Active optics, adaptive optics and other technical innovations; 6. European Northern Observatory and Calar Alto; 7. European Southern Observatory; 8. Mauna Kea Observatory; 9. Australian optical observatories; 10. Mount Hopkins' Whipple Observatory and the MMT; 11. Apache Point Observatory; 12. Carnegie Southern Observatory (Las Campanas); 13. Mount Graham International Optical Observatory; 14. Modern optical interferometers; 15. Solar observatories; Part II. Radio Observatories: 16. Australian radio observatories; 17. Cambridge Mullard Radio Observatory; 18. Jodrell Bank; 19. Early radio observatories away from the Australian-British axis; 20. The American National Radio Astronomy Observatory; 21. Owens Valley and Mauna Kea; 22. Further North and Central American observatories; 23. Further European and Asian radio observatories; 24. ALMA and the South Pole; Name index; Optical observatory and telescope index; Radio observatory and telescope index; General index.

  7. The Aula Espazio Gela Observatory: A tool for Solar System Education and Outreach

    Science.gov (United States)

    Rojas, J. F.; Perez-Hoyos, S.; Hueso, R.; Mendikoa, I.; Sanchez-Lavega, A.

    2011-10-01

    We present a summary of the activities undertaken over the first year of operations of the "Aula Espazio Gela Observatory", with teaching and astronomy outreach purposes. The observatory belongs to the Universidad del País Vasco and is a fundamental part of the "Master en Ciencia y Tecnología Espacial" (Space Science and Technology master). It is an urban observatory with the dome located on the roof of the School of Engineering at the Universidad del Pais Vasco in Bilbao (Spain).

  8. Solar dynamic power systems for space station

    Science.gov (United States)

    Irvine, Thomas B.; Nall, Marsha M.; Seidel, Robert C.

    1986-01-01

    The Parabolic Offset Linearly Actuated Reflector (POLAR) solar dynamic module was selected as the baseline design for a solar dynamic power system aboard the space station. The POLAR concept was chosen over other candidate designs after extensive trade studies. The primary advantages of the POLAR concept are the low mass moment of inertia of the module about the transverse boom and the compactness of the stowed module which enables packaging of two complete modules in the Shuttle orbiter payload bay. The fine pointing control system required for the solar dynamic module has been studied and initial results indicate that if disturbances from the station are allowed to back drive the rotary alpha joint, pointing errors caused by transient loads on the space station can be minimized. This would allow pointing controls to operate in bandwidths near system structural frequencies. The incorporation of the fine pointing control system into the solar dynamic module is fairly straightforward for the three strut concentrator support structure. However, results of structural analyses indicate that this three strut support is not optimum. Incorporation of a vernier pointing system into the proposed six strut support structure is being studied.

  9. The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, P.; /Lisbon, LIFEP /Lisbon, IST; Aglietta, M.; /Turin Observ. /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab; Allard, D.; /APC, Paris; Allekotte, I.; /Centro Atomico Bariloche /Balseiro Inst., San Carlos de Bariloche; Allen, J.; /New York U.; Alvarez Castillo, J.; /Mexico U.; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /Naples U. /INFN, Naples; Aminaei, A.; /Nijmegen U., IMAPP; Anchordoqui, L.; /Wisconsin U., Milwaukee /Lisbon, LIFEP /Lisbon, IST

    2011-01-01

    Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.

  10. Statistical Investigation and Modeling of Sungrazing Comets Discovered with the Solar and Heliospheric Observatory

    Science.gov (United States)

    Sekanina, Zdenek

    2002-02-01

    More than 300 sungrazing comets, most of them discovered with the Solar and Heliospheric Observatory (SOHO) coronagraphs since the beginning of 1996, are known to belong to the Kreutz group or system. Moving about the Sun in similar orbits, they are of indisputably common parentage and represent by far the most extensive data set in the history of investigations of cometary splitting. This study compares the SOHO sungrazers, which always disappear during their approach to the Sun, with the sungrazers detected earlier with the other space-borne coronagraphs (Solwind and Solar Maximum Mission [SMM]) as well as with the bright members of the Kreutz system, discovered from the ground between 1843 and 1970. Collected, summarized, and reviewed information on the sungrazers' light curves indicates that there is a difference of 20 mag (a factor of 108 in brightness) between the brightest sungrazer, C/1882 R1, and the faintest objects detectable with the SOHO instruments. The headless comet C/1887 B1 is suggested to be a transition object between the bright sungrazers and the coronagraphically discovered ones: its physical behavior was similar to that of the latter comets, but it survived the perihelion passage. This study also (1) examines temporal and spatial distributions of the SOHO sungrazers; (2) depicts correlations among their orbital elements; (3) distinguishes among tidally triggered, post-tidal, and terminal fragmentation; (4) reiterates the conclusion made in an earlier paper that post-tidal, secondary fragmentation events are occurring throughout the orbit, including the region of aphelion; (5) determines the relationship between a breakup's location in the orbit and the perturbations of the orbital elements of a fragment caused by the momentum it acquires during the separation from the parent; (6) shows that collisions of the Kreutz system comets with the Sun are clearly possible; (7) finds that minor fragments acquire enough extra momentum during each of the

  11. Solar neutrinos, helioseismology and the solar internal dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Turck-Chieze, Sylvaine [Service d' Astrophysique/IRFU/DSM/CEA, 91191 Gif sur Yvette Cedex (France); Couvidat, Sebastien, E-mail: sylvaine.turck-chieze@cea.fr, E-mail: couvidat@stanford.edu [HEPL, Stanford University, Stanford, CA 94305 (United States)

    2011-08-15

    Neutrinos are fundamental particles ubiquitous in the Universe and whose properties remain elusive despite more than 50 years of intense research activity. This review illustrates the importance of solar neutrinos in astrophysics, nuclear physics and particle physics. After a description of the historical context, we remind the reader of the noticeable properties of these particles and of the stakes of the solar neutrino puzzle. The standard solar model triggered persistent efforts in fundamental physics to predict the solar neutrino fluxes, and its constantly evolving predictions have been regularly compared with the detected neutrino signals. Anticipating that this standard model could not reproduce the internal solar dynamics, a seismic solar model was developed which enriched theoretical neutrino flux predictions with in situ observation of acoustic and gravity waves propagating in the Sun. This seismic model contributed to the stabilization of the neutrino flux predictions. This review recalls the main historical steps, from the pioneering Homestake mine experiment and the GALLEX-SAGE experiments capturing the first proton-proton neutrinos. It emphasizes the importance of the SuperKamiokande and SNO detectors. Both experiments demonstrated that the solar-emitted electron neutrinos are partially transformed into other neutrino flavors before reaching the Earth. This sustained experimental effort opens the door to neutrino astronomy, with long-base lines and underground detectors. The success of BOREXINO in detecting the {sup 7}Be neutrino signal alone instills confidence in physicists' ability to detect each neutrino source separately. It justifies the building of a new generation of detectors to measure the entire solar neutrino spectrum in greater detail, as well as supernova neutrinos. A coherent picture has emerged from neutrino physics and helioseismology. Today, new paradigms take shape in these two fields: neutrinos are massive particles, but their

  12. Testing relativity with solar system dynamics

    Science.gov (United States)

    Hellings, R. W.

    1984-01-01

    A major breakthrough is described in the accuracy of Solar System dynamical tests of relativistic gravity. The breakthrough was achieved by factoring in ranging data from Viking Landers 1 and 2 from the surface of Mars. Other key data sources included optical transit circle observations, lunar laser ranging, planetary radar, and spacecraft (Mariner 9 to Mars and Mariner 10 to Mercury). The Solar System model which is used to fit the data and the process by which such fits are performed are explained and results are discussed. The results are fully consistent with the predictions of General Relativity.

  13. Localization of the solar flare SF900610 in X-rays with the WATCH instrument of the GRANAT observatory

    DEFF Research Database (Denmark)

    Terekhov, O.V.; Kuzmin, A.G.; Shevchenko, A.V.

    2002-01-01

    -ray source do not coincide with the coordinates of the Ha-line flare. The X-ray source moved over the solar disk during the flare. This probably implies that, as the X-ray emission was generated, different parts of one loop or a system of magnetic loops dominated at different flare times.......During the solar flare of June 10, 1990, the WATCH instrument of the GRANAT space observatory obtained 110 localizations of the X-ray source in the X-ray range 8-20 keV. Its coordinates were measured with an accuracy of similar to2 arcmin at a 3sigma confidence level. The coordinates of the X...

  14. Solar Flare Dynamic Microwave Imaging with EOVSA

    Science.gov (United States)

    Gary, D. E.; Chen, B.; Nita, G. M.; Fleishman, G. D.; Yu, S.; White, S. M.; Hurford, G. J.; McTiernan, J. M.

    2017-12-01

    The Expanded Owens Valley Solar Array (EOVSA) is both an expansion of our existing solar array and serves as a prototype for a much larger future project, the Frequency Agile Solar Radiotelescope (FASR). EOVSA is now complete, and is producing daily imaging of the full solar disk, including active regions and solar radio bursts at hundreds of frequencies in the range 2.8-18 GHz. We present highlights of the 1-s-cadence dynamic imaging spectroscropy of radio bursts we have obtained to date, along with deeper analysis of multi-wavelength observations and modeling of a well-observed burst. These observations are revealing the full life-cycle of the trapped population of high-energy electrons, from their initial acceleration and subsequent energy-evolution to their eventual decay through escape and thermalization. All of our data are being made available for download in both quick-look image form and in the form of the community-standard CASA measurement sets for subsequent imaging and analysis.

  15. The Planetary Virtual Observatory and Laboratory (PVOL) and its integration into the Virtual European Solar and Planetary Access (VESPA)

    Science.gov (United States)

    Hueso, R.; Juaristi, J.; Legarreta, J.; Sánchez-Lavega, A.; Rojas, J. F.; Erard, S.; Cecconi, B.; Le Sidaner, Pierre

    2018-01-01

    Since 2003 the Planetary Virtual Observatory and Laboratory (PVOL) has been storing and serving publicly through its web site a large database of amateur observations of the Giant Planets (Hueso et al., 2010a). These images are used for scientific research of the atmospheric dynamics and cloud structure on these planets and constitute a powerful resource to address time variable phenomena in their atmospheres. Advances over the last decade in observation techniques, and a wider recognition by professional astronomers of the quality of amateur observations, have resulted in the need to upgrade this database. We here present major advances in the PVOL database, which has evolved into a full virtual planetary observatory encompassing also observations of Mercury, Venus, Mars, the Moon and the Galilean satellites. Besides the new objects, the images can be tagged and the database allows simple and complex searches over the data. The new web service: PVOL2 is available online in http://pvol2.ehu.eus/.

  16. Solar dynamic power system definition study

    Science.gov (United States)

    Wallin, Wayne E.; Friefeld, Jerry M.

    1988-01-01

    The solar dynamic power system design and analysis study compared Brayton, alkali-metal Rankine, and free-piston Stirling cycles with silicon planar and GaAs concentrator photovoltaic power systems for application to missions beyond the Phase 2 Space Station level of technology for all power systems. Conceptual designs for Brayton and Stirling power systems were developed for 35 kWe and 7 kWe power levels. All power systems were designed for 7-year end-of-life conditions in low Earth orbit. LiF was selected for thermal energy storage for the solar dynamic systems. Results indicate that the Stirling cycle systems have the highest performance (lowest weight and area) followed by the Brayton cycle, with photovoltaic systems considerably lower in performance. For example, based on the performance assumptions used, the planar silicon power system weight was 55 to 75 percent higher than for the Stirling system. A technology program was developed to address areas wherein significant performance improvements could be realized relative to the current state-of-the-art as represented by Space Station. In addition, a preliminary evaluation of hardenability potential found that solar dynamic systems can be hardened beyond the hardness inherent in the conceptual designs of this study.

  17. Modeling observations of solar coronal mass ejections with heliospheric imagers verified with the eliophysics System Observatory

    Czech Academy of Sciences Publication Activity Database

    Möstl, C.; Isavnin, A.; Boakes, P. D.; Kilpua, E. K. J.; Davies, J. A.; Harrison, R. A.; Barnes, D.; Krupař, Vratislav; Eastwood, J.; Good, S. W.; Forsyth, R. J.; Bothmer, V.; Reiss, M. A.; Amerstorfer, T.; Winslow, R. M.; Anderson, B.J.; Philpott, L. C.; Rodriguez, L.; Rouillard, A. P.; Gallagher, P.; Nieves-Chinchilla, T.; Zhang, T. L.

    2017-01-01

    Roč. 15, č. 7 (2017), s. 955-970 ISSN 1539-4956 R&D Projects: GA ČR(CZ) GJ17-06818Y Institutional support: RVO:68378289 Keywords : space weather * coronal mass ejections * STEREO * heliospheric imagers * Heliophysics System Observatory * heliophysics Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) http://onlinelibrary.wiley.com/doi/10.1002/2017SW001614/full

  18. Error Budget for a Calibration Demonstration System for the Reflected Solar Instrument for the Climate Absolute Radiance and Refractivity Observatory

    Science.gov (United States)

    Thome, Kurtis; McCorkel, Joel; McAndrew, Brendan

    2013-01-01

    A goal of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is to observe highaccuracy, long-term climate change trends over decadal time scales. The key to such a goal is to improving the accuracy of SI traceable absolute calibration across infrared and reflected solar wavelengths allowing climate change to be separated from the limit of natural variability. The advances required to reach on-orbit absolute accuracy to allow climate change observations to survive data gaps exist at NIST in the laboratory, but still need demonstration that the advances can move successfully from to NASA and/or instrument vendor capabilities for spaceborne instruments. The current work describes the radiometric calibration error budget for the Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer (SOLARIS) which is the calibration demonstration system (CDS) for the reflected solar portion of CLARREO. The goal of the CDS is to allow the testing and evaluation of calibration approaches, alternate design and/or implementation approaches and components for the CLARREO mission. SOLARIS also provides a test-bed for detector technologies, non-linearity determination and uncertainties, and application of future technology developments and suggested spacecraft instrument design modifications. The resulting SI-traceable error budget for reflectance retrieval using solar irradiance as a reference and methods for laboratory-based, absolute calibration suitable for climatequality data collections is given. Key components in the error budget are geometry differences between the solar and earth views, knowledge of attenuator behavior when viewing the sun, and sensor behavior such as detector linearity and noise behavior. Methods for demonstrating this error budget are also presented.

  19. Dynamics and Control of a Flexible Solar Sail

    OpenAIRE

    Jiafu Liu; Siyuan Rong; Fan Shen; Naigang Cui

    2014-01-01

    Solar sail can merely make use of solar radiation pressure (SRP) force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP), and sliding masses. Then the dynamic models for attitude/vibration contr...

  20. Preliminary results from the Orbiting Solar Observatory 8 - Observations of optically thin lines

    Science.gov (United States)

    Shine, R. A.; Roussel-Dupre, D.; Bruner, E. C., Jr.; Chipman, E. G.; Lites, B. W.; Rottman, G. J.; Athay, R. G.; White, O. R.

    1976-01-01

    The University of Colorado spectrometer aboard OSO 8 has measured the high temperature C IV resonance lines (at 1548 and 1551 A) and the Si IV resonance lines (at 1393 and 1402 A) formed in the solar chromosphere-corona transition region. Preliminary results include studies of mean profiles, a comparison of cell and network profiles, and the behavior of the lines at the extreme solar limb.

  1. CME Dynamics Using STEREO and LASCO Observations: The Relative Importance of Lorentz Forces and Solar Wind Drag

    Science.gov (United States)

    Sachdeva, Nishtha; Subramanian, Prasad; Vourlidas, Angelos; Bothmer, Volker

    2017-09-01

    We seek to quantify the relative contributions of Lorentz forces and aerodynamic drag on the propagation of solar coronal mass ejections (CMEs). We use Graduated Cylindrical Shell (GCS) model fits to a representative set of 38 CMEs observed with the Solar and Heliospheric Observatory (SOHO) and the Solar and Terrestrial Relations Observatory (STEREO) spacecraft. We find that the Lorentz forces generally peak between 1.65 and 2.45 R⊙ for all CMEs. For fast CMEs, Lorentz forces become negligible in comparison to aerodynamic drag as early as 3.5 - 4 R⊙. For slow CMEs, however, they become negligible only by 12 - 50 R⊙. For these slow events, our results suggest that some of the magnetic flux might be expended in CME expansion or heating. In other words, not all of it contributes to the propagation. Our results are expected to be important in building a physical model for understanding the Sun-Earth dynamics of CMEs.

  2. MULTISCALE DYNAMICS OF SOLAR MAGNETIC STRUCTURES

    International Nuclear Information System (INIS)

    Uritsky, Vadim M.; Davila, Joseph M.

    2012-01-01

    Multiscale topological complexity of the solar magnetic field is among the primary factors controlling energy release in the corona, including associated processes in the photospheric and chromospheric boundaries. We present a new approach for analyzing multiscale behavior of the photospheric magnetic flux underlying these dynamics as depicted by a sequence of high-resolution solar magnetograms. The approach involves two basic processing steps: (1) identification of timing and location of magnetic flux origin and demise events (as defined by DeForest et al.) by tracking spatiotemporal evolution of unipolar and bipolar photospheric regions, and (2) analysis of collective behavior of the detected magnetic events using a generalized version of the Grassberger-Procaccia correlation integral algorithm. The scale-free nature of the developed algorithms makes it possible to characterize the dynamics of the photospheric network across a wide range of distances and relaxation times. Three types of photospheric conditions are considered to test the method: a quiet photosphere, a solar active region (NOAA 10365) in a quiescent non-flaring state, and the same active region during a period of M-class flares. The results obtained show (1) the presence of a topologically complex asymmetrically fragmented magnetic network in the quiet photosphere driven by meso- and supergranulation, (2) the formation of non-potential magnetic structures with complex polarity separation lines inside the active region, and (3) statistical signatures of canceling bipolar magnetic structures coinciding with flaring activity in the active region. Each of these effects can represent an unstable magnetic configuration acting as an energy source for coronal dissipation and heating.

  3. SSALMON - The Solar Simulations for the Atacama Large Millimeter Observatory Network

    Czech Academy of Sciences Publication Activity Database

    Wedemeyer, S.; Bastian, T.S.; Brajsa, R.; Bárta, Miroslav; Hudson, H. S.; Fleishman, G.; Loukitcheva, M.; Fleck, B.; Kontar, E.; de Pontieu, B.; Tiwari, S.; Kato, Y.; Soler, R.; Yagoubov, P.; Black, J.H.; Antolin, P.; Gunár, Stanislav; Labrosse, N.; Benz, A. O.; Nindos, A.; Steffen, M.; Scullion, E.; Doyle, J.G.; Zaqarashvili, T.; Hanslmeier, A.; Nakariakov, V. M.; Heinzel, Petr; Ayres, T.; Karlický, Marian

    2015-01-01

    Roč. 56, č. 12 (2015), s. 2679-2692 ISSN 0273-1177 R&D Projects: GA ČR GA13-24782S EU Projects: European Commission(XE) 312495 Institutional support: RVO:67985815 Keywords : solar atmosphere * chromosphere * millimeter radiation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.409, year: 2015

  4. Structure and dynamics of solar atmosphere: the reign of SOHO

    International Nuclear Information System (INIS)

    Bocchialini, Karine

    2004-01-01

    In this report for Accreditation to Supervise Research (HDR), the author proposes an overview of his research works which particularly addressed the study of the solar atmosphere, notably based on observations made by the SOHO (Solar and Heliospheric Observatory) satellite. After a recall of his curriculum, he presents and comments results obtained in various areas: Corona heating and origin of solar wind, heating by waves, heating by quasi-steady mechanisms, regions which are sources of fast solar wind, sources of Coronal matter ejections. He also presents the different adopted approaches and methods (multi-wavelength analysis, oscillation measurement, statistical analysis) and the various observed structures (chromospheric network, shiny points, Coronal holes, and protuberances)

  5. NEW Fe IX LINE IDENTIFICATIONS USING SOLAR AND HELIOSPHERIC OBSERVATORY/SOLAR ULTRAVIOLET MEASUREMENT OF EMITTED RADIATION AND HINODE/EIS JOINT OBSERVATIONS OF THE QUIET SUN

    International Nuclear Information System (INIS)

    Landi, E.; Young, P. R.

    2009-01-01

    In this work, we study joint observations of Hinode/EUV Imaging Spectrometer (EIS) and Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation of Fe IX lines emitted by the same level of the high energy configuration 3s 2 3p 5 4p. The intensity ratios of these lines are dependent on atomic physics parameters only and not on the physical parameters of the emitting plasma, so that they are excellent tools to verify the relative intensity calibration of high-resolution spectrometers that work in the 170-200 A and 700-850 A wavelength ranges. We carry out extensive atomic physics calculations to improve the accuracy of the predicted intensity ratio, and compare the results with simultaneous EIS-SUMER observations of an off-disk quiet Sun region. We were able to identify two ultraviolet lines in the SUMER spectrum that are emitted by the same level that emits one bright line in the EIS wavelength range. Comparison between predicted and measured intensity ratios, wavelengths and energy separation of Fe IX levels confirms the identifications we make. Blending and calibration uncertainties are discussed. The results of this work are important for cross-calibrating EIS and SUMER, as well as future instrumentation.

  6. Solar magnetic field - 1976 through 1985: an atlas of photospheric magnetic field observations and computed coronal magnetic fields from the John M. Wilcox Solar Observatory at Stanford, 1976-1985

    International Nuclear Information System (INIS)

    Hoeksema, J.T.; Scherrer, P.H.

    1986-01-01

    Daily magnetogram observations of the large-scale photospheric magnetic field have been made at the John M. Wilcox Solar Observatory at Stanford since May of 1976. These measurements provide a homogeneous record of the changing solar field through most of Solar Cycle 21. Using the photospheric data, the configuration of the coronal and heliospheric fields can be calculated using a Potential Field -- Source Surface model. This provides a 3-dimensional picture of the heliospheric field-evolution during the solar cycle. In this report the authors present the complete set of synoptic charts of the measured photospheric magnetic field, the computed field at the source surface, and the coefficients of the multipole expansion of the coronal field. The general underlying structure of the solar and heliospheric fields, which determine the environment for solar - terrestrial relations and provide the context within which solar-activity-related events occur, can be approximated from these data

  7. Observatory of photovoltaic solar energy in France. Launching of the 19. edition - Quarterly publication, September 2016

    International Nuclear Information System (INIS)

    2016-09-01

    After a brief and synthetic overview of trends regarding solar photovoltaic energy in France and in the World (evolution of the numbers of connections and installations), this publication proposes graphs which illustrate the evolution of the distribution of new electricity production capacities in France, in Europe and in the USA, the evolution of connected photovoltaic power in the different World regions, a comparison of levelized cost of electricity between the different production sources, the evolution of the share of photovoltaic electricity in raw power consumption, the quarterly evolution of the number and power of connected photovoltaic installations between 2008 and 2016, the quarterly evolution of connections and purchase prices for different power ranges (less than 9 kW, 9-100 kW, 100-250 kW, 250 kW-1 MW, more than 1 MW), the evolution of the number and power of queuing projects, the quarterly evolution of solar photovoltaic electricity purchase prices in France, the evolution of the impact on the CSPE (contribution to the electricity public service)

  8. The thermal environment of the fiber glass dome for the new solar telescope at Big Bear Solar Observatory

    Science.gov (United States)

    Verdoni, A. P.; Denker, C.; Varsik, J. R.; Shumko, S.; Nenow, J.; Coulter, R.

    2007-09-01

    The New Solar Telescope (NST) is a 1.6-meter off-axis Gregory-type telescope with an equatorial mount and an open optical support structure. To mitigate the temperature fluctuations along the exposed optical path, the effects of local/dome-related seeing have to be minimized. To accomplish this, NST will be housed in a 5/8-sphere fiberglass dome that is outfitted with 14 active vents evenly spaced around its perimeter. The 14 vents house louvers that open and close independently of one another to regulate and direct the passage of air through the dome. In January 2006, 16 thermal probes were installed throughout the dome and the temperature distribution was measured. The measurements confirmed the existence of a strong thermal gradient on the order of 5° Celsius inside the dome. In December 2006, a second set of temperature measurements were made using different louver configurations. In this study, we present the results of these measurements along with their integration into the thermal control system (ThCS) and the overall telescope control system (TCS).

  9. Recent Progress in Heliogyro Solar Sail Structural Dynamics

    Science.gov (United States)

    Wilkie, William K.; Warren, Jerry E.; Horta, Lucas G.; Juang, Jer-Nan; Gibbs, Samuel C.; Dowell, E.; Guerrant, Daniel; Lawrence Dale

    2014-01-01

    Results from recent National Aeronautics and Space Administration (NASA) research on the structural dynamics and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment, and results from small-scale in vacuo dynamics experiments with spinning high-aspect ratio membranes. A low-cost, rideshare payload heliogyro technology demonstration mission concept, used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, is also described.

  10. Orbital Dynamics of a Simple Solar Photon Thruster

    Directory of Open Access Journals (Sweden)

    Anna D. Guerman

    2009-01-01

    Full Text Available We study orbital dynamics of a compound solar sail, namely, a Simple Solar Photon Thruster and compare its behavior to that of a common version of sailcraft. To perform this analysis, development of a mathematical model for force created by light reflection on all sailcraft elements is essential. We deduce the equations of sailcraft's motion and compare performance of two schemes of solar propulsion for two test time-optimal control problems of trajectory transfer.

  11. Orbital Dynamics of a Simple Solar Photon Thruster

    OpenAIRE

    Guerman, Anna D.; Smirnov, Georgi V.; Pereira, Maria Cecilia

    2009-01-01

    We study orbital dynamics of a compound solar sail, namely, a Simple Solar Photon Thruster and compare its behavior to that of a common version of sailcraft. To perform this analysis, development of a mathematical model for force created by light reflection on all sailcraft elements is essential. We deduce the equations of sailcraft's motion and compare performance of two schemes of solar propulsion for two test time-optimal control problems of trajectory transfer.

  12. Helioseismology and the Solar Interior Dynamics

    Indian Academy of Sciences (India)

    tribpo

    gives information on the internal solar rotation: while differential rotation exists in the ... show that lithium has been depleted by a factor of about 140 compared to the proto- solar value ... 2.1 Theory of element settling in the Sun and the stars.

  13. Analysis of dynamic effects in solar thermal energy conversion systems

    Science.gov (United States)

    Hamilton, C. L.

    1978-01-01

    The paper examines a study the purpose of which is to assess the performance of solar thermal power systems insofar as it depends on the dynamic character of system components and the solar radiation which drives them. Using a dynamic model, the daily operation of two conceptual solar conversion systems was simulated under varying operating strategies and several different time-dependent radiation intensity functions. These curves ranged from smoothly varying input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours.

  14. Dynamic kirigami structures for integrated solar tracking

    Science.gov (United States)

    Lamoureux, Aaron; Lee, Kyusang; Shlian, Matthew; Forrest, Stephen R.; Shtein, Max

    2015-01-01

    Optical tracking is often combined with conventional flat panel solar cells to maximize electrical power generation over the course of a day. However, conventional trackers are complex and often require costly and cumbersome structural components to support system weight. Here we use kirigami (the art of paper cutting) to realize novel solar cells where tracking is integral to the structure at the substrate level. Specifically, an elegant cut pattern is made in thin-film gallium arsenide solar cells, which are then stretched to produce an array of tilted surface elements which can be controlled to within ±1°. We analyze the combined optical and mechanical properties of the tracking system, and demonstrate a mechanically robust system with optical tracking efficiencies matching conventional trackers. This design suggests a pathway towards enabling new applications for solar tracking, as well as inspiring a broader range of optoelectronic and mechanical devices. PMID:26348820

  15. Prediction of transits of Solar system objects in Kepler/K2 images: an extension of the Virtual Observatory service SkyBoT

    Science.gov (United States)

    Berthier, J.; Carry, B.; Vachier, F.; Eggl, S.; Santerne, A.

    2016-05-01

    All the fields of the extended space mission Kepler/K2 are located within the ecliptic. Many Solar system objects thus cross the K2 stellar masks on a regular basis. We aim at providing to the entire community a simple tool to search and identify Solar system objects serendipitously observed by Kepler. The sky body tracker (SkyBoT) service hosted at Institut de mécanique céleste et de calcul des éphémérides provides a Virtual Observatory compliant cone search that lists all Solar system objects present within a field of view at a given epoch. To generate such a list in a timely manner, ephemerides are pre-computed, updated weekly, and stored in a relational data base to ensure a fast access. The SkyBoT web service can now be used with Kepler. Solar system objects within a small (few arcminutes) field of view are identified and listed in less than 10 s. Generating object data for the entire K2 field of view (14°) takes about a minute. This extension of the SkyBoT service opens new possibilities with respect to mining K2 data for Solar system science, as well as removing Solar system objects from stellar photometric time series.

  16. Analyses of the Photospheric Magnetic Dynamics in Solar Active Region 11117 Using an Advanced CESE-MHD Model

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Chaowei [SIGMA Weather Group, State Key Laboratory for Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL (United States); Wu, Shi T. [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL (United States); Department of Mechanical and Aerospace Engineering, The University of Alabama in Huntsville, AL (United States); Feng, Xueshang, E-mail: cwjiang@spaceweather.ac.cn [SIGMA Weather Group, State Key Laboratory for Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China)

    2016-05-10

    In this study, the photospheric vector magnetograms obtained by Helioseismic and Magnetic Imager on-board the Solar Dynamics Observatory are used as boundary conditions for a CESE-MHD model to investigate some photosphere characteristics around the time of a confined flare in solar active region NOAA AR 11117. We report our attempt of characterizing a more realistic solar atmosphere by including a plasma with temperature stratified from the photosphere to the corona in the CESE-MHD model. The resulted photospheric transverse flow is comparable to the apparent movements of the magnetic flux features that demonstrates shearing and rotations. We calculated the relevant parameters such as the magnetic energy flux and helicity flux, and with analysis of these parameters, we find that magnetic non-potentiality is transported across the photosphere into the corona in the simulated time interval, which might provide a favorable condition for producing the flare.

  17. Hint of nonstandard Mikheyev-Smirnov-Wolfenstein dynamics in solar neutrino conversion

    International Nuclear Information System (INIS)

    Palazzo, Antonio

    2011-01-01

    Motivated by the recent low-threshold measurements of the solar 8 B neutrino spectrum performed by Borexino, Super-Kamiokande and the Sudbury Neutrino Observatory--all now monitoring the transition regime between low-energy (vacuumlike) and high-energy (matter-dominated) flavor conversions--we consider the role of subdominant dynamical terms induced by new flavor-changing interactions. We find that the presence of such perturbations with strength ∼10 -1 G F is now favored, offering a better description of the anomalous behavior suggested by the new results, whose spectrum shows no sign of the typical low-energy upturn predicted by the standard Mikheyev-Smirnov-Wolfenstein (MSW) mechanism. Our findings, if interpreted in a 2-flavor scheme, provide a hint of such new interactions at the ∼2σ level, which is rather robust with respect to 3-flavor effects possibly induced by nonzero θ 13 .

  18. Chromospheric Variability: Analysis of 36 years of Time Series from the National Solar Observatory/Sacramento Peak Ca II K-line Monitoring Program

    Science.gov (United States)

    Scargle, Jeffrey D.; Keil, Stephen L.; Worden, Simon P.

    2014-01-01

    Analysis of more than 36 years of time series of seven parameters measured in the NSO/AFRL/Sac Peak K-line monitoring program elucidates five elucidates five components of the variation: (1) the solar cycle (period approx. 11 years), (2) quasi-periodic variations (periods approx 100 days), (3) a broad band stochastic process (wide range of periods), (4) rotational modulation, and (5) random observational errors. Correlation and power spectrum analyses elucidate periodic and aperiodic variation of the chromospheric parameters. Time-frequency analysis illuminates periodic and quasi periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (1) and (2) at time scales in the range approx 0.1 - 10 years. These results using only full-disk data further suggest that similar analyses will be useful at detecting and characterizing differential rotation in stars from stellar light-curves such as those being produced by NASA's Kepler observatory. Component (3) consists of variations over a range of timescales, in the manner of a 1/f random noise process. A timedependent Wilson-Bappu effect appears to be present in the solar cycle variations (1), but not in the stochastic process (3). Component (4) characterizes differential rotation of the active regions, and (5) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The recent data suggest that the current cycle is starting late and may be relatively weak. The data analyzed in this paper can be found at the National Solar Observatory web site http://nsosp.nso.edu/cak_mon/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

  19. Dynamics of the solar transition zone

    Science.gov (United States)

    Bruner, E. C., Jr.

    1978-01-01

    Time-resolved profiles of the 1548-A C IV line arising from the solar transition region are analyzed in order to determine whether the 300-sec oscillations characteristic of the photosphere and chromosphere penetrate into the transition zone and to measure the rms amplitude of transition-zone disturbances as well as their dependence on solar activity. The rms velocity amplitude is used to set limits on the mechanical energy flux available for solar heating. A power-spectrum analysis indicates that acoustic waves appear to have been detected in the transition zone, that at least one case of a strong 200- to 300-sec oscillation was observed, but that strong periodicities are not found on the average in either the intensity or the velocity field. It is suggested that the rms velocity that may be attributed to directly observable wave motion is between 3 and 7 km/s, depending on whether the individual emission elements seen in rocket spectra are coherent or independent in phase.

  20. Solar Dynamics and Its Effects on the Heliosphere and Earth

    CERN Document Server

    Baker, D. N; Schwartz, S. J; Schwenn, R; Steiger, R

    2007-01-01

    The SOHO and Cluster missions form a single ESA cornerstone. Yet they observe very different regions in our solar system: the solar atmosphere on one hand and the Earth’s magnetosphere on the other. At the same time the Ulysses mission provides observations in the third dimension of the heliosphere, and many others add to the picture from the Lagrangian point L1 to the edge of the heliosphere. It is the aim of this ISSI volume to tie these observations together in addressing the topic of Solar Dynamics and its Effects on the Heliosphere and Earth, thus contributing to the International Living With a Star (ILWS) program. The volume starts out with an assessment and description of the reasons for solar dynamics and how it couples into the heliosphere. The three subsequent sections are each devoted to following one chain of events from the Sun all the way to the Earth’s magnetosphere and ionosphere: The normal solar wind chain, the chain associated with coronal mass ejections, and the solar energetic particl...

  1. Dynamic Modeling of Natural Convection Solar Energy Flat Plate ...

    African Journals Online (AJOL)

    The analytical solutions to the dynamic model of an air-heating flat plate solar energy thermal collector were validated by direct measurement from a physical model constructed for that purpose, of the temperatures of the cover and absorber plates, the inlet and outlet fluids, and the ambient air from morning to evening for ...

  2. Photoexcitation dynamics in organic solar cell donor/acceptor system

    Energy Technology Data Exchange (ETDEWEB)

    Aarnio, H.

    2012-07-01

    In this work, photoinduced absorption techniques have been used in a number of ways to clarify the charge generation and recombination processes in two polymers used in organic solar cells, namely APFO3 and P3HT. Emphasis has been on identifying photoexcitations, modeling their dynamics and determining their lifetimes.

  3. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  4. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  5. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  6. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  7. Dynamics of the solar transition zone

    International Nuclear Information System (INIS)

    Bruner, E.C. Jr.

    1978-01-01

    This paper reports on the analysis of time-resolved C IV line profiles arising from the solar transition zone. Objectives were twofold: to determine whether the 300 s photospheric oscillations penetrate to the transition zone, and to measure the rms velocity disturbance amplitude and its dependence upon solar activity. The data set consisted of 44 times sequences of 50 min average duration and included samples from study experiments of both active and quiet regions of the disk. Power-spectrum analysis of the time series of intensity and line position measurements showed at least one example of a well-developed 300 s oscillation. There was no evidence, however, for 300 s peaks in the average power spectra either in the quiet network or in active regions.The rms velocities were found to be about 2.3 km s - 1 in active regions and 5.7 km s -1 in quiet regions. The suggested average value, allowing for the substantial statistical noise contribution to the quiet Sun data, is about 3 km s -1 . The inferred energy flux, assuming energy transport by acoustic waves, is at most 1.6 x 10 4 ergs cm -2 s -1 for spatial scales greater than 15,000 km and periods in the range 100--1800 s. The acoustic-wave hypothesis apparently fails by at least one order of magnitude to provide the 2--6 x 10 5 ergs cm -2 s -1 thought to be required to replace coronal energy losses. The data are, however, consistent with heating mechanisms based on energy transport by magnetohydrodynamic waves

  8. Distributed solar radiation fast dynamic measurement for PV cells

    Science.gov (United States)

    Wan, Xuefen; Yang, Yi; Cui, Jian; Du, Xingjing; Zheng, Tao; Sardar, Muhammad Sohail

    2017-10-01

    To study the operating characteristics about PV cells, attention must be given to the dynamic behavior of the solar radiation. The dynamic behaviors of annual, monthly, daily and hourly averages of solar radiation have been studied in detail. But faster dynamic behaviors of solar radiation need more researches. The solar radiation random fluctuations in minute-long or second-long range, which lead to alternating radiation and cool down/warm up PV cell frequently, decrease conversion efficiency. Fast dynamic processes of solar radiation are mainly relevant to stochastic moving of clouds. Even in clear sky condition, the solar irradiations show a certain degree of fast variation. To evaluate operating characteristics of PV cells under fast dynamic irradiation, a solar radiation measuring array (SRMA) based on large active area photodiode, LoRa spread spectrum communication and nanoWatt MCU is proposed. This cross photodiodes structure tracks fast stochastic moving of clouds. To compensate response time of pyranometer and reduce system cost, the terminal nodes with low-cost fast-responded large active area photodiode are placed besides positions of tested PV cells. A central node, consists with pyranometer, large active area photodiode, wind detector and host computer, is placed in the center of the central topologies coordinate to scale temporal envelope of solar irradiation and get calibration information between pyranometer and large active area photodiodes. In our SRMA system, the terminal nodes are designed based on Microchip's nanoWatt XLP PIC16F1947. FDS-100 is adopted for large active area photodiode in terminal nodes and host computer. The output current and voltage of each PV cell are monitored by I/V measurement. AS62-T27/SX1278 LoRa communication modules are used for communicating between terminal nodes and host computer. Because the LoRa LPWAN (Low Power Wide Area Network) specification provides seamless interoperability among Smart Things without the

  9. Dynamics and Control of a Flexible Solar Sail

    Directory of Open Access Journals (Sweden)

    Jiafu Liu

    2014-01-01

    Full Text Available Solar sail can merely make use of solar radiation pressure (SRP force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP, and sliding masses. Then the dynamic models for attitude/vibration controller design and dynamic simulation are obtained, respectively. The linear quadratic regulator (LQR based and optimal proportional-integral (PI based controllers are designed for the coupled attitude/vibration models with constant disturbance torques caused by the center-of-mass (cm/center-of-pressure (cp offset, respectively. It can be concluded from the theoretical analysis and simulation results that the optimal PI based controller performs better than the LQR based controller from the view of eliminating the steady-state errors. The responses with and without the geometrical nonlinearity are performed, and the differences are observed and analyzed. And some suggestions are also presented.

  10. Phase change energy storage for solar dynamic power systems

    Science.gov (United States)

    Chiaramonte, F. P.; Taylor, J. D.

    1992-01-01

    This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

  11. Solar wind dynamic pressure variations and transient magnetospheric signatures

    International Nuclear Information System (INIS)

    Sibeck, D.G.; Baumjohann, W.

    1989-01-01

    Contrary to the prevailing popular view, we find some transient ground events with bipolar north-south signatures are related to variations in solar wind dynamic pressure and not necessarily to magnetic merging. We present simultaneous solar wind plasma observations for two previously reported transient ground events observed at dayside auroral latitudes. During the first event, originally reported by Lanzerotti et al. [1987], conjugate ground magnetometers recorded north-south magetic field deflections in the east-west and vertical directions. The second event was reported by Todd et al. [1986], we noted ground rader observations indicating strong northward then southward ionospheric flows. The events were associated with the postulated signatures of patchy, sporadic, merging of magnetosheath and magnetospheric magnetic field lines at the dayside magnetospause, known as flux transfer events. Conversely, we demonstrate that the event reported by Lanzerotti et al. was accompanied by a sharp increase in solar wind dynamic pressure, a magnetospheric compression, and a consequent ringing of the magnetospheric magnetic field. The event reported by Todd et al. was associated with a brief but sharp increase in the solar wind dynamic pressure. copyright American Geophysical Union 1989

  12. A New Approach to Observing Coronal Dynamics: MUSE, the Multi-Slit Solar Explorer

    Science.gov (United States)

    Tarbell, T. D.

    2017-12-01

    The Multi-Slit Solar Explorer is a Small Explorer mission recently selected for a Phase A study, which could lead to a launch in 2022. It will provide unprecendented observations of the dynamics of the corona and transition region using both conventional and novel spectral imaging techniques. The physical processes that heat the multi-million degree solar corona, accelerate the solar wind and drive solar activity (CMEs and flares) remain poorly known. A breakthrough in these areas can only come from radically innovative instrumentation and state-of-the-art numerical modeling and will lead to better understanding of space weather origins. MUSE's multi-slit coronal spectroscopy will exploit a 100x improvement in spectral raster cadence to fill a crucial gap in our knowledge of Sun-Earth connections; it will reveal temperatures, velocities and non-thermal processes over a wide temperature range to diagnose physical processes that remain invisible to current or planned instruments. MUSE will contain two instruments: an EUV spectrograph (SG) and EUV context imager (CI). Both have similar spatial resolution and leverage extensive heritage from previous high-resolution instruments such as IRIS and the HiC rocket payload. The MUSE investigation will build on the success of IRIS by combining numerical modeling with a uniquely capable observatory: MUSE will obtain EUV spectra and images with the highest resolution in space (1/3 arcsec) and time (1-4 s) ever achieved for the transition region and corona, along 35 slits and a large context FOV simultaneously. The MUSE consortium includes LMSAL, SAO, Stanford, ARC, HAO, GSFC, MSFC, MSU, ITA Oslo and other institutions.

  13. Measurement of the nue and Total 8B Solar Neutrino Fluxes with theSudbury Neutrino Observatory Phase I Data Set

    Energy Technology Data Exchange (ETDEWEB)

    Aharmim, B.; Ahmad, Q.R.; Ahmed, S.N.; Allen, R.C.; Andersen,T.C.; Anglin, J.D.; Buehler, G.; Barton, J.C.; Beier, E.W.; Bercovitch,M.; Bergevin, M.; Bigu, J.; Biller, S.D.; Black, R.A.; Blevis, I.; Boardman, R.J.; Boger, J.; Bonvin, E.; Boulay, M.G.; Bowler, M.G.; Bowles, T.J.; Brice, S.J.; Browne, M.C.; Bullard, T.V.; Burritt, T.H.; Cameron, J.; Chan, Y.D.; Chen, H.H.; Chen, M.; Chen, X.; Cleveland, B.T.; Cowan, J.H.M.; Cowen, D.F.; Cox, G.A.; Currat, C.A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W.F.; Deng, H.; DiMarco, M.; Doe, P.J.; Doucas, G.; Dragowsky, M.R.; Duba, C.A.; Duncan, F.A.; Dunford, M.; Dunmore, J.A.; Earle, E.D.; Elliott, S.R.; Evans, H.C.; Ewan, G.T.; Farine, J.; Fergani, H.; Ferraris, A.P.; Fleurot, F.; Ford, R.J.; Formaggio, J.A.; Fowler, M.M.; Frame, K.; Frank, E.D.; Frati, W.; Gagnon,N.; Germani, J.V.; Gil, S.; Goldschmidt, A.; Goon, J.T.M.; Graham, K.; Grant, D.R.; Guillian, E.; Hahn, R.L.; Hallin, A.L.; Hallman, E.D.; Hamer, A.S.; Hamian, A.A.; Handler, W.B.; Haq, R.U.; Hargrove, C.K.; Harvey, P.J.; Hazama, R.; Heeger, K.M.; Heintzelman, W.J.; Heise, J.; Helmer, R.L.; Henning, R.; Hepburn, J.D.; Heron, H.; Hewett, J.; Hime,A.; Howard, C.; Howe, M.A.; Huang, M.; Hykawy, J.G.; Isaac, M.C.P.; Jagam, P.; Jamieson, B.; Jelley, N.A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P.T.; Kirch, K.; Klein, J.R.; Knox, A.B.; Komar,R.J.; Kormos, L.L.; Kos, M.; Kouzes, R.; Krueger, A.; Kraus, C.; Krauss,C.B.; Kutter, T.; Kyba, C.C.M.; Labranche, H.; Lange, R.; Law, J.; Lawson, I.T.; Lay, M.; Lee, H.W.; Lesko, K.T.; Leslie, J.R.; Levine, I.; Loach, J.C.; Locke, W.; Luoma, S.; Lyon, J.; MacLellan, R.; Majerus, S.; Mak, H.B.; Maneira, J.; Marino, A.D.; Martin, R.; McCauley, N.; McDonald,A.B.; McDonald, D.S.; McFarlane, K.; McGee, S.; McGregor, G.; MeijerDrees, R.; Mes, H.; Mifflin, C.; Miknaitis, K.K.S.; Miller, M.L.; Milton,G.; Moffat, B.A.; Monreal, B.; Moorhead, M.; Morrissette, B.; Nally,C.W.; Neubauer, M.S.; et al.

    2007-02-01

    This article provides the complete description of resultsfrom the Phase I data set of the Sudbury Neutrino Observatory (SNO). ThePhase I data set is based on a 0.65 kt-year exposure of heavy water tothe solar 8B neutrino flux. Included here are details of the SNO physicsand detector model, evaluations of systematic uncertainties, andestimates of backgrounds. Also discussed are SNO's approach tostatistical extraction of the signals from the three neutrino reactions(charged current, neutral current, and elastic scattering) and theresults of a search for a day-night asymmetry in the ?e flux. Under theassumption that the 8B spectrum is undistorted, the measurements fromthis phase yield a solar ?e flux of ?(?e) =1.76+0.05?0.05(stat.)+0.09?0.09 (syst.) x 106 cm?2 s?1, and a non-?ecomponent ?(? mu) = 3.41+0.45?0.45(stat.)+0.48?0.45 (syst.) x 106 cm?2s?1. The sum of these components provides a total flux in excellentagreement with the predictions of Standard Solar Models. The day-nightasymmetry in the ?e flux is found to be Ae = 7.0 +- 4.9 (stat.)+1.3?1.2percent (sys.), when the asymmetry in the total flux is constrained to bezero.

  14. Plasma dynamics above solar flare soft x-ray loop tops

    Energy Technology Data Exchange (ETDEWEB)

    Doschek, G. A.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); McKenzie, D. E. [Montana State University, Bozeman, MT 59717 (United States)

    2014-06-10

    We measure non-thermal motions in flare loop tops and above the loop tops using profiles of highly ionized spectral lines of Fe XXIV and Fe XXIII formed at multimillion-degree temperatures. Non-thermal motions that may be due to turbulence or multiple flow regions along the line of sight are extracted from the line profiles. The non-thermal motions are measured for four flares seen at or close to the solar limb. The profile data are obtained using the Extreme-ultraviolet Imaging Spectrometer on the Hinode spacecraft. The multimillion-degree non-thermal motions are between 20 and 60 km s{sup –1} and appear to increase with height above the loop tops. Motions determined from coronal lines (i.e., lines formed at about 1.5 MK) tend to be smaller. The multimillion-degree temperatures in the loop tops and above range from about 11 MK to 15 MK and also tend to increase with height above the bright X-ray-emitting loop tops. The non-thermal motions measured along the line of sight, as well as their apparent increase with height, are supported by Solar Dynamics Observatory Atmospheric Imaging Assembly measurements of turbulent velocities in the plane of the sky.

  15. Time variations of oxygen emission lines and solar wind dynamic parameters in low latitude region

    Science.gov (United States)

    Jamlongkul, P.; Wannawichian, S.; Mkrtichian, D.; Sawangwit, U.; A-thano, N.

    2017-09-01

    Aurora phenomenon is an effect of collision between precipitating particles with gyromotion along Earth’s magnetic field and Earth’s ionospheric atoms or molecules. The particles’ precipitation occurs normally around polar regions. However, some auroral particles can reach lower latitude regions when they are highly energetic. A clear emission from Earth’s aurora is mostly from atomic oxygen. Moreover, the sun’s activities can influence the occurrence of the aurora as well. This work studies time variations of oxygen emission lines and solar wind parameters, simultaneously. The emission’s spectral lines were observed by Medium Resolution Echelle Spectrograph (MRES) along with 2.4 meters diameter telescope at Thai National Observatory, Intanon Mountain, Chiang Mai, Thailand. Oxygen (OI) emission lines were calibrated by Dech-Fits spectra processing program and Dech95 2D image processing program. The correlations between oxygen emission lines and solar wind dynamics will be analyzed. This result could be an evidence of the aurora in low latitude region.

  16. Preliminary results from the orbiting solar observatory 8: Transition-zone dynamics over a sunspot

    International Nuclear Information System (INIS)

    Bruner, E.C. Jr.; Chipman, E.G.; Lites, B.W.; Rottman, G.J.; Shine, R.A.; Athay, R.G.; White, O.R.

    1976-01-01

    The University of Colorado experiment aboard OSO-8 observed the C IV 1548 A line in the bright plume over a sunspot. Transient redshifts at 5 minute intervals were studied, but the expected phenomena associated with simple Alfven wave effects were not observed

  17. A heat receiver design for solar dynamic space power systems

    Science.gov (United States)

    Baker, Karl W.; Dustin, Miles O.; Crane, Roger

    1990-01-01

    An advanced heat pipe receiver designed for a solar dynamic space power system is described. The power system consists of a solar concentrator, solar heat receiver, Stirling heat engine, linear alternator and waste heat radiator. The solar concentrator focuses the sun's energy into a heat receiver. The engine and alternator convert a portion of this energy to electric power and the remaining heat is rejected by a waste heat radiator. Primary liquid metal heat pipes transport heat energy to the Stirling engine. Thermal energy storage allows this power system to operate during the shade portion of an orbit. Lithium fluoride/calcium fluoride eutectic is the thermal energy storage material. Thermal energy storage canisters are attached to the midsection of each heat pipe. The primary heat pipes pass through a secondary vapor cavity heat pipe near the engine and receiver interface. The secondary vapor cavity heat pipe serves three important functions. First, it smooths out hot spots in the solar cavity and provides even distribution of heat to the engine. Second, the event of a heat pipe failure, the secondary heat pipe cavity can efficiently transfer heat from other operating primary heat pipes to the engine heat exchanger of the defunct heat pipe. Third, the secondary heat pipe vapor cavity reduces temperature drops caused by heat flow into the engine. This unique design provides a high level of reliability and performance.

  18. Going 'green': trade specialisation dynamics in the solar photovoltaic sector

    International Nuclear Information System (INIS)

    Algieri, Bernardina; Aquino, Antonio; Succurro, Marianna

    2011-01-01

    The present study aims at providing a comprehensive analysis of trade flows and the domestic value creation of the major solar photovoltaic industry at the world level. Solar technologies convert light and heat from the sun into useful energy. The use of the sun's energy can not only reduce the consumption of conventional fuels, thus reducing the emission of detrimental greenhouse gases, but it can also enable a gain in enhanced fuel and energy security along with lessening costs. In addition, green technologies and industries can promote economic growth and international competitiveness, and can offer new business and employment opportunities. It becomes, therefore, extremely important to deeply explore the dynamics of the solar photovoltaic sector. Specifically, the present work analyses the main global trends of this sector and sketches the key players on the world market, including producers, installers, and top traders. Based on an analysis of trade flows at the 6-digit level, the international specialisation patterns are investigated, and the role of various market and trade drivers, including subsidies in the uptake of solar technologies, is identified and examined. - Highlights: → Trade specialisation in solar photovoltaics is examined using an index analysis. → Trade of the US, UK and Germany has an intra-industry nature. → Trade of Italy, Greece and Japan is more inter-industry oriented. → There is a long-run relationship between PV exports, foreign income and prices.

  19. Attitude Dynamics and Stability of a Simple Solar Photon Thruster

    Directory of Open Access Journals (Sweden)

    Anna D. Guerman

    2013-01-01

    Full Text Available This paper is dedicated to the development of a model of the attitude dynamics for a nonideal Simple Solar Photon Thruster (SSPT and to the analysis of sailcraft motions with respect to their centre of mass. Derivation of the expressions for force and torque due to solar radiation that is valid for the case, when there is a misalignment of the SSPT axis with the sun direction, is followed by study of sailcraft dynamics and stability properties. Analysis of stability shows that an ideally reflecting sail is unstable, while for a sailcraft with nonideal collector, the symmetry axis is stable with respect to the Sun direction for large variety of system parameters. The motion around symmetry axis is always unstable and requires an active stabilizer.

  20. Dynamical 3-Space Gravity Theory: Effects on Polytropic Solar Models

    Directory of Open Access Journals (Sweden)

    May R. D.

    2011-01-01

    Full Text Available Numerous experiments and observations have confirmed the existence of a dynamical 3-space, detectable directly by light-speed anisotropy experiments, and indirectly by means of novel gravitational effects, such as bore hole g anomalies, predictable black hole masses, flat spiral-galaxy rotation curves, and the expansion of the universe, all without dark matter and dark energy. The dynamics for this 3-space follows from a unique generalisation of Newtonian gravity, once that is cast into a velocity formalism. This new theory of gravity is applied to the solar model of the sun to compute new density, pressure and temperature profiles, using polytrope modelling of the equation of state for the matter. These results should be applied to a re-analysis of solar neutrino production, and to stellar evolution in general.

  1. Formation and dynamics of a solar eruptive flux tube

    Science.gov (United States)

    Inoue, Satoshi; Kusano, Kanya; Büchner, Jörg; Skála, Jan

    2018-01-01

    Solar eruptions are well-known drivers of extreme space weather, which can greatly disturb the Earth's magnetosphere and ionosphere. The triggering process and initial dynamics of these eruptions are still an area of intense study. Here we perform a magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the dynamics of a solar eruption in a real magnetic environment. In our simulation, we confirmed that tether-cutting reconnection occurring locally above the polarity inversion line creates a twisted flux tube, which is lifted into a toroidal unstable area where it loses equilibrium, destroying the force-free state, and driving the eruption. Consequently, a more highly twisted flux tube is built up during this initial phase, which can be further accelerated even when it returns to a stable area. We suggest that a nonlinear positive feedback process between the flux tube evolution and reconnection is the key to ensure this extra acceleration.

  2. Radiator selection for Space Station Solar Dynamic Power Systems

    Science.gov (United States)

    Fleming, Mike; Hoehn, Frank

    A study was conducted to define the best radiator for heat rejection of the Space Station Solar Dynamic Power System. Included in the study were radiators for both the Organic Rankine Cycle and Closed Brayton Cycle heat engines. A number of potential approaches were considered for the Organic Rankine Cycle and a constructable radiator was chosen. Detailed optimizations of this concept were conducted resulting in a baseline for inclusion into the ORC Preliminary Design. A number of approaches were also considered for the CBC radiator. For this application a deployed pumped liquid radiator was selected which was also refined resulting in a baseline for the CBC preliminary design. This paper reports the results and methodology of these studies and describes the preliminary designs of the Space Station Solar Dynamic Power System radiators for both of the candidate heat engine cycles.

  3. Dynamic model of an autonomous solar absorption refrigerator

    International Nuclear Information System (INIS)

    Ali Fellah; Tahar Khir; Ammar Ben Brahim

    2009-01-01

    The performance analysis of a solar absorption refrigerator operating in an autonomous way is investigated. The water/LiBr machine satisfies the air-conditioning needs along the day. The refrigerator performances were simulated regarding a dynamic model. For the solar driven absorption machines, two applications could be distinguished. The sun provides the thermal part of the useful energy. In this case, it is necessary to use additional energy as the electric one to activate the pumps, the fans and the control system. On the other hand, the sun provides all the necessary energy. Here, both photovoltaic cells and thermal concentrators should be used. The simulation in dynamic regime of the cycle requires the knowledge of the geometric characteristics of every component as the exchange areas and the internal volumes. Real characteristics of a refrigerator available at the applied thermodynamic research unit (ATRU) at the engineers' national school of Gabes are notified. The development of the thermal and matter balances in every component of the cycle has permitted to simulate in dynamic regime the performances of a solar absorption refrigerator operating with the water/LiBr couple for air-conditioning needs. The developed model could be used to perform intermittent refrigeration cycle autonomously driven. (author)

  4. Preliminary results from the orbiting solar observatory 8: Persistent velocity fields in the chromosphere and transition region

    International Nuclear Information System (INIS)

    Lites, B.W.; Bruner, E.C. Jr.; Chipman, E.G.; Shine, R.A.; Rottman, G.J.; White, O.R.; Athay, R.G.

    1976-01-01

    Velocity images, or tachograms, of the solar chromosphere and chromosphere-corona transition region were made by measuring the Si II 1816.93 A chromospheric line and the Si IV 1393.8 A transition region line with the University of Colorado spectrometer aboard OSO-8. Persistent flows are indicated in both active and quiet regions of the solar atmosphere. In quiet regions, areas of enhanced emission (the chromospheric network) are apparently systematically redshifted with respect to the areas of lower intensity. This correlation does not hold in active regions, where long-lived downflows into sunspots have been observed

  5. Yanqing solar field: Dynamic optical model and operational safety analysis

    International Nuclear Information System (INIS)

    Zhao, Dongming; Wang, Zhifeng; Xu, Ershu; Zhu, Lingzhi; Lei, Dongqiang; Xu, Li; Yuan, Guofeng

    2017-01-01

    Highlights: • A dynamic optical model of the Yanqing solar field was built. • Tracking angle characteristics were studied with different SCA layouts and time. • The average energy flux was simulated across four clear days. • Influences of defocus angles for energy flux were analyzed. - Abstract: A dynamic optical model was established for the Yanqing solar field at the parabolic trough solar thermal power plant and a simulation was conducted on four separate days of clear weather (March 3rd, June 2nd, September 25th, December 17th). The solar collector assembly (SCA) was comprised of a North-South and East-West layout. The model consisted of the following modules: DNI, SCA operational, and SCA optical. The tracking angle characteristics were analyzed and the results showed that the East-West layout of the tracking system was the most viable. The average energy flux was simulated for a given time period and different SCA layouts, yielding an average flux of 6 kW/m 2 , which was then used as the design and operational standards of the Yanqing parabolic trough plant. The mass flow of North-South layout was relatively stable. The influences of the defocus angles on both the average energy flux and the circumferential flux distribution were also studied. The results provided a theoretical basis for the following components: solar field design, mass flow control of the heat transfer fluid, design and operation of the tracking system, operational safety of SCAs, and power production prediction in the Yanqing 1 MW parabolic trough plant.

  6. Soil Moisture/ Tree Water Status Dynamics in Mid-Latitude Montane Forest, Southern Sierra Critical Zone Observatory, CA

    Science.gov (United States)

    Hartsough, P. C.; Malazian, A.; Meadows, M. W.; Roudneva, K.; Storch, J.; Bales, R. C.; Hopmans, J. W.

    2010-12-01

    As part of an effort to understand the root-water-nutrient interactions in the multi-dimensional soil/vegetation system surrounding large trees, in August 2008 we instrumented a mature white fir (Abies concolor) and the surrounding soil to better define the water balance in a single tree. In July 2010, we instrumented a second tree, a Ponderosa pine (Pinus ponderosa) in shallower soils on a drier, exposed slope. The trees are located in a mixed-conifer forest at an elevation of 2000m in the Southern Sierra Critical Zone Observatory. The deployment of more than 250 sensors to measure temperature, volumetric water content, matric potential, and snow depth surrounding the two trees complements sap-flow measurements in the trunk and stem-water-potential measurements in the canopy to capture the seasonal cycles of soil wetting and drying. We show here the results of a multi-year deployment of soil moisture sensors as critical integrators of hydrologic/ biotic interaction in a forested catchment. Sensor networks such as deployed here are a valuable tool in closing the water budget in dynamic forested catchments. While the exchange of energy, water and carbon is continuous, the pertinent fluxes are strongly heterogeneous in both space and time. Thus, the prediction of the behavior of the system across multiple scales constitutes a major challenge.

  7. Rhythms and community dynamics of a hydrothermal tubeworm assemblage at main endeavour field - a multidisciplinary deep-sea observatory approach.

    Directory of Open Access Journals (Sweden)

    Daphne Cuvelier

    Full Text Available The NEPTUNE cabled observatory network hosts an ecological module called TEMPO-mini that focuses on hydrothermal vent ecology and time series, granting us real-time access to data originating from the deep sea. In 2011-2012, during TEMPO-mini's first deployment on the NEPTUNE network, the module recorded high-resolution imagery, temperature, iron (Fe and oxygen on a hydrothermal assemblage at 2186 m depth at Main Endeavour Field (North East Pacific. 23 days of continuous imagery were analysed with an hourly frequency. Community dynamics were analysed in detail for Ridgeia piscesae tubeworms, Polynoidae, Pycnogonida and Buccinidae, documenting faunal variations, natural change and biotic interactions in the filmed tubeworm assemblage as well as links with the local environment. Semi-diurnal and diurnal periods were identified both in fauna and environment, revealing the influence of tidal cycles. Species interactions were described and distribution patterns were indicative of possible microhabitat preference. The importance of high-resolution frequencies (<1 h to fully comprehend rhythms in fauna and environment was emphasised, as well as the need for the development of automated or semi-automated imagery analysis tools.

  8. Production of solar radiation bankable datasets from high-resolution solar irradiance derived with dynamical downscaling Numerical Weather prediction model

    Directory of Open Access Journals (Sweden)

    Yassine Charabi

    2016-11-01

    Full Text Available A bankable solar radiation database is required for the financial viability of solar energy project. Accurate estimation of solar energy resources in a country is very important for proper siting, sizing and life cycle cost analysis of solar energy systems. During the last decade an important progress has been made to develop multiple solar irradiance database (Global Horizontal Irradiance (GHI and Direct Normal Irradiance (DNI, using satellite of different resolution and sophisticated models. This paper assesses the performance of High-resolution solar irradiance derived with dynamical downscaling Numerical Weather Prediction model with, GIS topographical solar radiation model, satellite data and ground measurements, for the production of bankable solar radiation datasets. For this investigation, NWP model namely Consortium for Small-scale Modeling (COSMO is used for the dynamical downscaling of solar radiation. The obtained results increase confidence in solar radiation data base obtained from dynamical downscaled NWP model. The mean bias of dynamical downscaled NWP model is small, on the order of a few percents for GHI, and it could be ranked as a bankable datasets. Fortunately, these data are usually archived in the meteorological department and gives a good idea of the hourly, monthly, and annual incident energy. Such short time-interval data are valuable in designing and operating the solar energy facility. The advantage of the NWP model is that it can be used for solar radiation forecast since it can estimate the weather condition within the next 72–120 hours. This gives a reasonable estimation of the solar radiation that in turns can be used to forecast the electric power generation by the solar power plant.

  9. My Teacher got a Trip to Kitt Peak Observatory, but all I got was This Lousy Data CD: Lessons Learned in Optimizing a Teacher Professional Development Program for Solar Research

    Science.gov (United States)

    Walker, C. E.; Hill, F.; Plymate, C.

    2005-12-01

    The solar project in "Teacher Leaders in Research-Based Science Education" program provides the opportunity for teachers to study the Sun with the world's largest solar telescope. This exciting program is designed for middle and high school science teachers with more than 5 years experience teaching science. Funded by a National Science Foundation (NSF) Teacher Retention and Renewal grant, teachers learn how to acquire astronomy data and support their students in conducting authentic astronomy research projects. In addition, the program enhances their skills as leaders and mentors for those science teachers new to the profession. The TLRBSE program includes: 1) A 14-week online distance learning program with an emphasis on spectroscopy and data imaging; 2) A 2-week in-residence workshop at the National Optical Astronomy Observatory in Tucson, including several nights of research observing at a world-class observatory; 3) A program of ongoing mentoring support for beginning teachers; and 4) Partial funding to attend a national NSTA meeting with the mentees; 5) A journal to publish student and teacher research results and 6) Access to ongoing research, via further observing runs or archival data. Various factors have played a part in the evolution of the solar project. It began as an activity that used sunspots to measure the solar rotation rate. Then it progressed to a comparison of active regions (e.g., the areas of sunspots) at various wavelengths, to measuring the splitting of infrared spectral lines due to strong magnetic fields in active regions, and to measuring the amount of polarization due to weak magnetic fields. Challenges were presented as the project evolved from an activity to a hands-on observing experience fully reflecting the scientific research process. Some of the issues and trade-offs we will discuss are hands-on observing experience vs. remote observing, archival data retrieval vs. talking data, and more vs. less scientific assistance in the

  10. Solar Dynamic Power System Stability Analysis and Control

    Science.gov (United States)

    Momoh, James A.; Wang, Yanchun

    1996-01-01

    The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

  11. South African Astronomical Observatory

    International Nuclear Information System (INIS)

    1987-01-01

    Work at the South African Astronomical Observatory (SAAO) in recent years, by both staff and visitors, has made major contributions to the fields of astrophysics and astronomy. During 1986 the SAAO has been involved in studies of the following: galaxies; celestial x-ray sources; magellanic clouds; pulsating variables; galactic structure; binary star phenomena; nebulae and interstellar matter; stellar astrophysics; open clusters; globular clusters, and solar systems

  12. Dynamics of Intense Currents in the Solar Wind

    Science.gov (United States)

    Artemyev, Anton V.; Angelopoulos, Vassilis; Halekas, Jasper S.; Vinogradov, Alexander A.; Vasko, Ivan Y.; Zelenyi, Lev M.

    2018-06-01

    Transient currents in the solar wind are carried by various magnetic field discontinuities that contribute significantly to the magnetic field fluctuation spectrum. Internal instabilities and dynamics of these discontinuities are believed to be responsible for magnetic field energy dissipation and corresponding charged particle acceleration and heating. Accurate modeling of these phenomena requires detailed investigation of transient current formation and evolution. By examining such evolution using a unique data set compiled from observations of the same solar wind flow by two spacecraft at Earth’s and Mars’s orbits, we show that it consists of several processes: discontinuity thinning (decrease in thickness normalized by the ion inertial length), intensification of currents normalized to the proton thermal current (i.e., the product of proton charge, density, and thermal velocity), and increase in the compressional component of magnetic field variations across discontinuities. The significant proton temperature variation around most observed discontinuities indicates possible proton heating. Plasma velocity jumps across the discontinuities are well correlated with Alfvén velocity changes. We discuss possible explanations of the observed discontinuity evolution. We also compare the observed evolution with predictions of models describing discontinuity formation due to Alfvén wave steepening. Our results show that discontinuity modeling likely requires taking into account both the effects of nonlinear Alfvén wave dynamics and solar wind expansion.

  13. FFT analysis of sensible-heat solar-dynamic receivers

    Science.gov (United States)

    Lund, Kurt O.

    The use of solar dynamic receivers with sensible energy storage in single-phase materials is considered. The feasibility of single-phase designs with weight and thermal performance comparable to existing two-phase designs is addressed. Linearized heat transfer equations are formulated for the receiver heat storage, representing the periodic input solar flux as the sum of steady and oscillating distributions. The steady component is solved analytically to produce the desired receiver steady outlet gas temperature, and the FFT algorithm is applied to the oscillating components to obtain the amplitudes and mode shapes of the oscillating solid and gas temperatures. The results indicate that sensible-heat receiver designs with performance comparable to state-of-the-art two-phase receivers are available.

  14. Thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.

    1985-01-01

    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  15. Charge carrier recombination dynamics in perovskite and polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Paulke, Andreas; Kniepert, Juliane; Kurpiers, Jona; Wolff, Christian M.; Schön, Natalie; Brenner, Thomas J. K.; Neher, Dieter [Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24–25, 14476, Potsdam (Germany); Stranks, Samuel D. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Snaith, Henry J. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2016-03-14

    Time-delayed collection field experiments are applied to planar organometal halide perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) based solar cells to investigate charge carrier recombination in a fully working solar cell at the nanosecond to microsecond time scale. Recombination of mobile (extractable) charges is shown to follow second-order recombination dynamics for all fluences and time scales tested. Most importantly, the bimolecular recombination coefficient is found to be time-dependent, with an initial value of ca. 10{sup −9} cm{sup 3}/s and a progressive reduction within the first tens of nanoseconds. Comparison to the prototypical organic bulk heterojunction device PTB7:PC{sub 71}BM yields important differences with regard to the mechanism and time scale of free carrier recombination.

  16. Einstein Observatory survey of X-ray emission from solar-type stars - the late F and G dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Maggio, A.; Sciortino, S.; Vaiana, G.S.; Majer, P.; Bookbinder, J.

    1987-04-01

    Results of a volume-limited X-ray survey of stars of luminosity classes IV and V in the spectral range F7-G9 observed with the Einstein Observatory are presented. Using survival analysis techniques, the stellar X-ray luminosity function in the 0.15-4.0 keV energy band for both single and multiple sources. It is shown that the difference in X-ray luminosity between these two classes of sources is consistent with the superposition of individual components in multiple-component systems, whose X-ray properties are similar to those of the single-component sources. The X-ray emission of the stars in our sample is well correlated with their chromospheric CA II H-K line emission and with their projected equatorial rotational velocity. Comparison of the X-ray luminosity function constructed for the sample of the dG stars of the local population with the corresponding functions derived elsewhere for the Hyades, the Pleiades, and the Orion Ic open cluster confirms that the level of X-ray emission decreases with stellar age. 62 references.

  17. Einstein Observatory survey of X-ray emission from solar-type stars - The late F and G dwarf stars

    Science.gov (United States)

    Maggio, A.; Sciortino, S.; Vaiana, G. S.; Majer, P.; Bookbinder, J.

    1987-01-01

    Results of a volume-limited X-ray survey of stars of luminosity classes IV and V in the spectral range F7-G9 observed with the Einstein Observatory are presented. Using survival analysis techniques, the stellar X-ray luminosity function in the 0.15-4.0 keV energy band for both single and multiple sources. It is shown that the difference in X-ray luminosity between these two classes of sources is consistent with the superposition of individual components in multiple-component systems, whose X-ray properties are similar to those of the single-component sources. The X-ray emission of the stars in our sample is well correlated with their chromospheric CA II H-K line emission and with their projected equatorial rotational velocity. Comparison of the X-ray luminosity function constructed for the sample of the dG stars of the local population with the corresponding functions derived elsewhere for the Hyades, the Pleiades, and the Orion Ic open cluster confirms that the level of X-ray emission decreases with stellar age.

  18. Investigations of Solar Prominence Dynamics Using Laboratory Simulations

    International Nuclear Information System (INIS)

    Bellan, Paul M.

    2008-01-01

    Laboratory experiments simulating many of the dynamical features of solar coronal loops have been carried out. These experiments manifest collimation, kinking, jet flows, and S-shapes. Diagnostics include high-speed photography and x-ray detectors. Two loops having opposite or the same magnetic helicity polarities have been merged and it is found that counter-helicity merging provides much greater x-ray emission. A non-MHD particle orbit instability has been discovered whereby ions going in the opposite direction of the current flow direction can be ejected from a magnetic flux tube.

  19. Numerical model of solar dynamic radiator for parametric analysis

    Science.gov (United States)

    Rhatigan, Jennifer L.

    1989-01-01

    Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations.

  20. Photographic Observations of Solar System Bodies at the Main Astronomical Observatory of NAS of Ukraine: Final Results

    Science.gov (United States)

    Golovnia, V.; Yizhakevych, O.; Shatokhina, S.; Andruk, V.

    Astrometric photographic observations of Solar system bodies in the frame of different programs were made at MAO NAN of Ukraine during 1950-2005. 9245 plates with the images of planets and their natural satellite, Moon, minor planets, comets and artificial satellites were obtained and processed in the late 20th century. At the beginning of the 21st century, the UkrVO Joint Digital Archive (JDA) was created, which is accessible at the MAO NAS resources (http://gua.db.ukr-vo.org/archivespecial.php). To digitize the plate archive for the JDA database, flat bed scanners were used and the software was specially de-veloped on the basis of the LINUX/MIDAS/ROMAFOT software for the processing of wide-field images, as well as searching for the images of minor planets and comets on the Northern sky survey program plates. Up to the present time, the photographic plates with images of outer planets and their satellites have been re-processed. The final result of the long-lasting program of the photographic positional observations of Solar system bodies are summarized and presented in this publication.

  1. Solar cooling. Dynamic computer simulations and parameter variations; Solare Kuehlung. Dynamische Rechnersimulationen und Parametervariationen

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Mario; Lohmann, Sandra [Fachhochschule Duesseldorf (Germany). E2 - Erneuerbare Energien und Energieeffizienz

    2011-05-15

    The research project 'Solar cooling in the Hardware-in-the-Loop-Test' is funded by the BMBF and deals with the modeling of a pilot plant for solar cooling with the 17.5 kW absorption chiller of Yazaki in the simulation environment of MATLAB/ Simulink with the toolboxes Stateflow and CARNOT. Dynamic simulations and parameter variations according to the work-efficient methodology of design of experiments are used to select meaningful system configurations, control strategies and dimensioning of the components. The results of these simulations will be presented and a view of the use of acquired knowledge for the planned laboratory field tests on a hardware-in-the-loop test stand will be given. (orig.)

  2. Dynamic screening in solar and stellar nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Daeppen, W. [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA (United States); Mussack, K. [Los Alamos National Laboratory, XTD-2, Los Alamos, NM (United States)

    2012-02-15

    In the hot, dense plasma of solar and stellar interiors, Coulomb potentials are screened, resulting in increased nuclear reaction rates. Although Salpeter's approximation for static screening is widely accepted and used in stellar modeling, the question of screening in nuclear reactions was revisited in the 1990s. In particular the issue of dynamic effects was raised by Shaviv and Shaviv, who applied the techniques of molecular dynamics to the conditions in the Sun's core in order to numerically determine the effect of screening. By directly calculating the motion of ions and electrons due to Coulomb interactions, the simulations are used to compute the effect of screening without the mean-field assumption inherent in Salpeter's approximation. In the last few years, the USC group has first reproduced Shaviv and Shaviv's numerical analysis of the screening energy, showing an effect of dynamic screening. When the consequence for the reaction-rate was computed, a rather surprising resulted, which is contrary to that from static screening theory. Our calculations showed that dynamic screening does not significantly change the reaction rate from that of the bare Coulomb potential. If this can be independently confirmed, then the effects of dynamic screening are highly relevant and should be included in stellar nuclear reaction rates (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Parameterization of Nitrogen Limitation for a Dynamic Ecohydrological Model: a Case Study from the Luquillo Critical Zone Observatory

    Science.gov (United States)

    Bastola, S.; Bras, R. L.

    2017-12-01

    Feedbacks between vegetation and the soil nutrient cycle are important in ecosystems where nitrogen limits plant growth, and consequently influences the carbon balance in the plant-soil system. However, many biosphere models do not include such feedbacks, because interactions between carbon and the nitrogen cycle can be complex, and remain poorly understood. In this study we coupled a nitrogen cycle model with an eco-hydrological model by using the concept of carbon cost economics. This concept accounts for different "costs" to the plant of acquiring nitrogen via different pathways. This study builds on tRIBS-VEGGIE, a spatially explicit hydrological model coupled with a model of photosynthesis, stomatal resistance, and energy balance, by combining it with a model of nitrogen recycling. Driven by climate and spatially explicit data of soils, vegetation and topography, the model (referred to as tRIBS-VEGGIE-CN) simulates the dynamics of carbon and nitrogen in the soil-plant system; the dynamics of vegetation; and different components of the hydrological cycle. The tRIBS-VEGGIE-CN is applied in a humid tropical watershed at the Luquillo Critical Zone Observatory (LCZO). The region is characterized by high availability and cycling of nitrogen, high soil respiration rates, and large carbon stocks.We drive the model under contemporary CO2 and hydro-climatic forcing and compare results to a simulation under doubling CO2 and a range of future climate scenarios. The results with parameterization of nitrogen limitation based on carbon cost economics show that the carbon cost of the acquisition of nitrogen is 14% of the net primary productivity (NPP) and the N uptake cost for different pathways vary over a large range depending on leaf nitrogen content, turnover rates of carbon in soil and nitrogen cycling processes. Moreover, the N fertilization simulation experiment shows that the application of N fertilizer does not significantly change the simulated NPP. Furthermore, an

  4. Observational study on the fine structure and dynamics of a solar jet. II. Energy release process revealed by spectral analysis

    Science.gov (United States)

    Sakaue, Takahito; Tei, Akiko; Asai, Ayumi; Ueno, Satoru; Ichimoto, Kiyoshi; Shibata, Kazunari

    2018-01-01

    We report on a solar jet phenomenon associated with the C5.4 class flare on 2014 November 11. The data of the jet was provided by the Solar Dynamics Observatory, the X-Ray Telescope (XRT) aboard Hinode, and the Interface Region Imaging Spectrograph and Domeless Solar Telescope (DST) at Hida Observatory, Kyoto University. These plentiful data enabled us to present this series of papers to discuss all the processes of the observed phenomena, including energy storage, event trigger, and energy release. In this paper, we focus on the energy release process of the observed jet, and mainly describe our spectral analysis on the Hα data of DST to investigate the internal structure of the Hα jet and its temporal evolution. This analysis reveals that in the physical quantity distributions of the Hα jet, such as line-of-sight velocity and optical thickness, there is a significant gradient in the direction crossing the jet. We interpret this internal structure as the consequence of the migration of the energy release site, based on the idea of ubiquitous reconnection. Moreover, by measuring the horizontal flow of the fine structures in the jet, we succeeded in deriving the three-dimensional velocity field and the line-of-sight acceleration field of the Hα jet. The analysis result indicates that part of the ejecta in the Hα jet experienced additional acceleration after it had been ejected from the lower atmosphere. This secondary acceleration was found to occur in the vicinity of the intersection between the trajectories of the Hα jet and the X-ray jet observed by Hinode/XRT. We propose that a fundamental cause of this phenomenon is magnetic reconnection involving the plasmoid in the observed jet.

  5. DYNAMICS IN SUNSPOT UMBRA AS SEEN IN NEW SOLAR TELESCOPE AND INTERFACE REGION IMAGING SPECTROGRAPH DATA

    Energy Technology Data Exchange (ETDEWEB)

    Yurchyshyn, V.; Abramenko, V. [Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States); Kilcik, A. [Department of Space Science and Technologies, Akdeniz University, 07058 Antalya (Turkey)

    2015-01-10

    We analyze sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) slit-jaw and spectral data and narrow-band chromospheric images from the New Solar Telescope (NST) for the main sunspot in NOAA AR 11836. We report that the difference between the shock arrival times as measured by the Mg II k 2796.35 Å and Si IV 1393.76 Å line formation levels changes during the observed period, and peak-to-peak delays may range from 40 s to zero. The intensity of chromospheric shocks also displays long-term (about 20 min) variations. NST's high spatial resolution Hα data allowed us to conclude that, in this sunspot, umbral flashes (UFs) appeared in the form of narrow bright lanes stretched along the light bridges and around clusters of umbral bright points. The time series also suggested that UFs preferred to appear on the sunspot-center side of light bridges, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. The sunspot's umbra as seen in the IRIS chromospheric and transition region data appears bright above the locations of light bridges and the areas where the dark umbra is dotted with clusters of umbral dots. Co-spatial and co-temporal data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory showed that the same locations were associated with bright footpoints of coronal loops suggesting that the light bridges may play an important role in heating the coronal sunspot loops. Finally, the power spectra analysis showed that the intensity of chromospheric and transition region oscillations significantly vary across the umbra and with height, suggesting that umbral non-uniformities and the structure of sunspot magnetic fields may play a role in wave propagation and heating of umbral loops.

  6. Water-mass dynamics of an Arctic cold-water coral reef: First results from a new ocean observatory system

    Science.gov (United States)

    Flögel, Sascha; Karstensen, Johannes; Linke, Peter; Pfannkuche, Olaf; Ashastina, Kseniia; Dullo, Christian

    2015-04-01

    Cold-water coral reefs occur at various sites along the European continental margin, like in the Mediterranean Sea, on carbonate mounds West off Ireland, or at shallower depths between 100 and 350 m on the Norwegian shelf. Their occurrence is related to different physical parameters like temperature, salinity, seawater density, dissolved oxygen, and to other environmental parameters such as internal wave activity, nutrient supply, strong currents, which keep sediment input low, etc. Here, we present first results from a long-term observation in one of the nortnermost cold-water coral reefs at 70.5°N - the Stjernsund in northern Norway. The Stjernsund is a 30 km long and up to 3.5 km wide sound connecting the open North Atlantic with a fjord system. A deep-seated SW-NE oriented morainic sill with varying depths (203-236 m) splits the more than 400 m deep sound into two troughs. Living Lophelia pertusa dominated reef complexes occur on the NW slope between 235 and 305 m water depths and on the SE slope between 245 and 280 m. To investigate the dominating physical and biogeochemical boundary conditions a new modular seafloor observatory, MoLab, consisting of five sea-floor observatories and two moorings was deployed for 100 days during the summer of 2012. The various lander systems and moorimgs were equipped with sensors to measure current velocities and directions, temperature, salinity, pressure, pH, turbidity, fluorescence, oxygen concentration and saturation. Results showed that near-bottom salinities, temperature and current velocities are dominated by a semi-diurnal tidal forcing (pronounced M2 constituent), which cause vertical water mass movements of up to 100 m. These influence large parts of the living reef. Closer examination revealed overturning cells on the south-eastern slope of the sill during high tide, when Atlantic Water flows over the sill. The appearance of living cold-water corals is limited to a density envelope of sigma-theta=27.25-27.50 kg/m-3

  7. Solar Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar photographic and illustrated datasets contributed by a number of national and private solar observatories located worldwide....

  8. Solar Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar feature datasets contributed by a number of national and private solar observatories located worldwide.

  9. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  10. New underground neutrino observatory-GENIUS-in the new millenium for solar neutrinos, dark matter and double beta decay

    CERN Document Server

    Klapdor-Kleingrothaus, H V

    2001-01-01

    Double beta decay is indispensable to solve the question of the neutrino mass matrix together with nu oscillation experiments. The most sensitive experiment for eight years-the HEIDELBERG-MOSCOW experiment in Gran-Sasso-already now, with the experimental limit of (m/sub nu /)<0.26 eV excludes degenerate nu mass scenarios allowing neutrinos as hot dark matter in the Universe for the small angle MSW solution of the solar neutrino problem. It probes cosmological models including hot dark matter already now on the level of future satellite experiments MAP and PLANCK. It further probes many topics of beyond standard model physics at the TeV scale. Future experiments should give access to the multiTeV range and complement on many ways the search for new physics at future colliders like LHC and NLC. For neutrino physics GENIUS will allow to test almost all neutrino mass scenarios allowed by the present neutrino oscillation experiments. At the same time GENIUS will cover a wide range of the parameter space of pred...

  11. Solar Adaptive Optics

    Directory of Open Access Journals (Sweden)

    Thomas R. Rimmele

    2011-06-01

    Full Text Available Adaptive optics (AO has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO and Ground-Layer AO (GLAO will be given.

  12. Solar Adaptive Optics.

    Science.gov (United States)

    Rimmele, Thomas R; Marino, Jose

    Adaptive optics (AO) has become an indispensable tool at ground-based solar telescopes. AO enables the ground-based observer to overcome the adverse effects of atmospheric seeing and obtain diffraction limited observations. Over the last decade adaptive optics systems have been deployed at major ground-based solar telescopes and revitalized ground-based solar astronomy. The relatively small aperture of solar telescopes and the bright source make solar AO possible for visible wavelengths where the majority of solar observations are still performed. Solar AO systems enable diffraction limited observations of the Sun for a significant fraction of the available observing time at ground-based solar telescopes, which often have a larger aperture than equivalent space based observatories, such as HINODE. New ground breaking scientific results have been achieved with solar adaptive optics and this trend continues. New large aperture telescopes are currently being deployed or are under construction. With the aid of solar AO these telescopes will obtain observations of the highly structured and dynamic solar atmosphere with unprecedented resolution. This paper reviews solar adaptive optics techniques and summarizes the recent progress in the field of solar adaptive optics. An outlook to future solar AO developments, including a discussion of Multi-Conjugate AO (MCAO) and Ground-Layer AO (GLAO) will be given. Supplementary material is available for this article at 10.12942/lrsp-2011-2.

  13. Compatibility of different measurement techniques of global solar radiation and application for long-term observations at Izaña Observatory

    Science.gov (United States)

    Delia García, Rosa; Cuevas, Emilio; García, Omaira Elena; Ramos, Ramón; Romero-Campos, Pedro Miguel; de Ory, Fernado; Cachorro, Victoria Eugenia; de Frutos, Angel

    2017-03-01

    A 1-year inter-comparison of classical and modern radiation and sunshine duration (SD) instruments has been performed at Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain) starting on 17 July 2014. We compare daily global solar radiation (GSRH) records measured with a Kipp & Zonen CM-21 pyranometer, taken in the framework of the Baseline Surface Radiation Network, with those measured with a multifilter rotating shadowband radiometer (MFRSR), a bimetallic pyranometer (PYR) and GSRH estimated from sunshine duration performed by a Campbell-Stokes sunshine recorder (CS) and a Kipp & Zonen sunshine duration sensor (CSD). Given that the BSRN GSRH records passed strict quality controls (based on principles of physical limits and comparison with the LibRadtran model), they have been used as reference in the inter-comparison study. We obtain an overall root mean square error (RMSE) of ˜ 0.9 MJm-2 (4 %) for PYR and MFRSR GSRH, 1.9 (7 %) and 1.2 MJm-2 (5 %) for CS and CSD GSRH, respectively. Factors such as temperature, relative humidity (RH) and the solar zenith angle (SZA) have been shown to moderately affect the GSRH observations. As an application of the methodology developed in this work, we have re-evaluated the GSRH data time series obtained at IZO with two PYRs between 1977 and 1991. Their high consistency and temporal stability have been proved by comparing with GSRH estimates obtained from SD observations. These results demonstrate that (1) the continuous-basis inter-comparison of different GSRH techniques offers important diagnostics for identifying inconsistencies between GSRH data records, and (2) the GSRH measurements performed with classical and more simple instruments are consistent with more modern techniques and, thus, valid to recover GSRH data time series and complete worldwide distributed GSRH data. The inter-comparison and quality assessment of these different techniques have allowed us to obtain a complete and consistent

  14. New techniques for the characterisation of dynamical phenomena in solar coronal images

    Science.gov (United States)

    Robbrecht, E.

    2007-02-01

    ) was an important step on the way to subarcsecond telescopes. It allows a spatial resolution of 1" in the EUV and UV bands and, simultaneously, a temporal resolution of the order of a few seconds. Coronal physics studies are dominated by two major and interlinked problems: coronal heating and solar wind acceleration. Above the chromosphere there is a thin transition layer in which the temperature suddenly increases and density drops. How can the temperature of the solar corona be three orders of magnitude higher than the temperature of the photosphere? In order for this huge temperature gradient to be stationary, non-thermal energy must be transported from below the photosphere towards the chromosphere and corona and converted into heat to balance the radiative and conductive losses. This puzzle of origin, transport and conversion of energy is referred to as the "coronal heating problem". Due to its fundamental role in the structuring of the corona, the magnetic field is supposed to play an important role in the heating. In this dissertation we describe two aspects of solar coronal dynamics: waves in coronal loops (Part I) and coronal mass ejections (Part II). We investigate the influence of (semi-) automated techniques on solar coronal research. This is a timely discussion since the observation of solar phenomena is transitioning from manual detection to "Solar Image Processing". Our results are mainly based on images from the Extreme UV Imaging Telescope (EIT) and the Large Angle and Spectrometric Coronagraph (LASCO), two instruments onboard the satellite SOHO (Solar and Heliospheric Observatory) of which we recently celebrated its 11th anniversary. The high quality of the images together with the long timespan created a valuable database for solar physics research. Part I reports on the first detection of slow magnetoacoustic waves in transequatorial coronal loops observed in high cadence image sequences simultaneously produced by EIT and TRACE (Transition Region

  15. 195-Year History of Mykolayiv Observatory: Events and People

    Directory of Open Access Journals (Sweden)

    Shulga, O.V.

    2017-01-01

    Full Text Available The basic stages of the history of the Mykolaiv Astronomical Observatory are shown. The main results of the Observatory activities are presented by the catalogs of star positions, major and minor planets in the Solar system, space objects in the Earth orbit. The information on the qualitative and quantitative structure of the Observatory, cooperation with the observatories of Ukraine and foreign countries as well as major projects carried out in the Observatory is provided.

  16. Solar Indices - Solar Radio Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  17. Analysis of Energy Efficiency in Dynamic Optical Networks Employing Solar Energy Sources

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2013-01-01

    The paper presents energy efficient routing in dynamic optical networks, where solar energy sources are employed for the network nodes. Different parameters are evaluated, including the number of nodes that have access to solar energy sources, the different maximum solar output power, traffic type...... and the locations of solar powered nodes. Results show a maximum 39% savings in energy consumption with different increases in connection blocking probability....

  18. Plasma dynamics in solar macrospicules from high-cadence extreme-UV observations

    Science.gov (United States)

    Loboda, I. P.; Bogachev, S. A.

    2017-01-01

    Macrospicules are relatively large spicule-like formations found mainly over the polar coronal holes when observing in the transition region spectral lines. In this study, we took advantage of the two short series of observations in the He II 304 Å line obtained by the TESIS solar observatory with a cadence of up to 3.5 s to study the dynamics of macrospicules in unprecedented detail. We used a one-dimensional hydrodynamic method based on the assumption of their axial symmetry and on a simple radiative transfer model to reconstruct the evolution of the internal velocity field of 18 macrospicules from this dataset. Besides the internal dynamics, we studied the motion of the apparent end points of the same 18 macrospicules and found 15 of them to follow parabolic trajectories with high precision which correspond closely to the obtained velocity fields. We found that in a clear, unperturbed case these macrospicules move with a constant deceleration inconsistent with a purely ballistic motion and have roughly the same velocity along their entire axis, with the obtained decelerations typically ranging from 160 to 230 m s-2, and initial velocities from 80 to 130 km s-1. We also found a propagating acoustic wave for one of the macrospicules and a clear linear correlation between the initial velocities of the macrospicules and their decelerations, which indicates that they may be driven by magneto-acoustic shocks. Finally, we inverted our previous method by taking velocities from the parabolic fits to give rough estimates of the percentage of mass lost by 12 of the macrospicules. We found that typically from 10 to 30% of their observed mass fades out of the line (presumably being heated to higher coronal temperatures) with three exceptions of 50% and one of 80%.

  19. Hybrid photovoltaic–thermal solar collectors dynamic modeling

    International Nuclear Information System (INIS)

    Amrizal, N.; Chemisana, D.; Rosell, J.I.

    2013-01-01

    Highlights: ► A hybrid photovoltaic/thermal dynamic model is presented. ► The model, once calibrated, can predict the power output for any set of climate data. ► The physical electrical model includes explicitly thermal and irradiance dependences. ► The results agree with those obtained through steady-state characterization. ► The model approaches the junction cell temperature through the system energy balance. -- Abstract: A hybrid photovoltaic/thermal transient model has been developed and validated experimentally. The methodology extends the quasi-dynamic thermal model stated in the EN 12975 in order to involve the electrical performance and consider the dynamic behavior minimizing constraints when characterizing the collector. A backward moving average filtering procedure has been applied to improve the model response for variable working conditions. Concerning the electrical part, the model includes the thermal and radiation dependences in its variables. The results revealed that the characteristic parameters included in the model agree reasonably well with the experimental values obtained from the standard steady-state and IV characteristic curve measurements. After a calibration process, the model is a suitable tool to predict the thermal and electrical performance of a hybrid solar collector, for a specific weather data set.

  20. Dynamical limits on dark mass in the outer solar system

    International Nuclear Information System (INIS)

    Hogg, D.W.; Quinlan, G.D.; Tremaine, S.

    1991-01-01

    Simplified model solar systems with known observational errors are considered in conducting a dynamical search for dark mass and its minimum detectable amount, and in determining the significance of observed anomalies. The numerical analysis of the dynamical influence of dark mass on the orbits of outer planets and comets is presented in detail. Most conclusions presented are based on observations of the four giant planets where the observational errors in latitude and longitude are independent Gaussian variables with a standard deviation. Neptune's long orbital period cannot be predicted by modern ephemerides, and no evidence of dark mass is found in considering this planet. Studying the improvement in fit when observations are fitted to models that consider dark mass is found to be an efficient way to detect dark mass. Planet X must have a mass of more than about 10 times the minimum detectable mass to locate the hypothetical planet. It is suggested that the IRAS survey would have already located the Planet X if it is so massive and close that it dynamically influences the outer planets. Orbital residuals from comets are found to be more effective than those from planets in detecting the Kuiper belt. 35 refs

  1. Dynamic Characterization of an Inflatable Concentrator for Solar Thermal Propulsion

    Science.gov (United States)

    Leigh, Larry; Hamidzadeh, Hamid; Tinker, Michael L.; Rodriguez, Pedro I. (Technical Monitor)

    2001-01-01

    An inflatable structural system that is a technology demonstrator for solar thermal propulsion and other applications is characterized for structural dynamic behavior both experimentally and computationally. The inflatable structure is a pressurized assembly developed for use in orbit to support a Fresnel lens or inflatable lenticular element for focusing sunlight into a solar thermal rocket engine. When the engine temperature reaches a pre-set level, the propellant is injected into the engine, absorbs heat from an exchanger, and is expanded through the nozzle to produce thrust. The inflatable structure is a passively adaptive system in that a regulator and relief valve are utilized to maintain pressure within design limits during the full range of orbital conditions. Modeling and test activities are complicated by the fact that the polyimide film material used for construction of the inflatable is nonlinear, with modulus varying as a function of frequency, temperature, and level of excitation. Modal vibration testing and finite element modeling are described in detail in this paper. The test database is used for validation and modification of the model. This work is highly significant because of the current interest in inflatable structures for space application, and because of the difficulty in accurately modeling such systems.

  2. Formation, evolution, and dynamics of young solar systems

    CERN Document Server

    Gressel, Oliver

    2017-01-01

    This book's interdisciplinary scope aims at bridging various communities: 1) cosmochemists, who study meteoritic samples from our own solar system, 2) (sub-) millimetre astronomers, who measure the distribution of dust and gas of star-forming regions and planet-forming discs, 3) disc modellers, who describe the complex photo-chemical structure of parametric discs to fit these to observation, 4) computational astrophysicists, who attempt to decipher the dynamical structure of magnetised gaseous discs, and the effects the resulting internal structure has on the aerodynamic re-distribution of embedded solids, 5) theoreticians in planet formation theory, who aim to piece it all together eventually arriving at a coherent holistic picture of the architectures of planetary systems discovered by 6) the exoplanet observers, who provide us with unprecedented samples of exoplanet worlds. Combining these diverse fields the book sheds light onto the riddles that research on planet formation is currently confronted with, a...

  3. Solar air heating system: design and dynamic simulation

    Science.gov (United States)

    Bououd, M.; Hachchadi, O.; Janusevicius, K.; Martinaitis, V.; Mechaqrane, A.

    2018-05-01

    The building sector is one of the big energy consumers in Morocco, accounting for about 23% of the country’s total energy consumption. Regarding the population growth, the modern lifestyle requiring more comfort and the increase of the use rate of electronic devices, the energy consumption will continue to increase in the future. In this context, the introduction of renewable energy systems, along with energy efficiency, is becoming a key factor in reducing the energy bill of buildings. This study focuses on the design and dynamic simulation of an air heating system for the mean categories of the tertiary sector where the area exceeds 750 m3. Heating system has been designed via a dynamic simulation environment (TRNSYS) to estimate the produced temperature and airflow rate by one system consisting of three essential components: vacuum tube solar collector, storage tank and water-to-air finned heat exchanger. The performances estimation of this system allows us to evaluate its capacity to meet the heating requirements in Ifrane city based on the prescriptive approach according to the Moroccan Thermal Regulation. The simulation results show that in order to maintain a comfort temperature of 20°C in a building of 750m3, the places requires a thermal powers of approximately 21 kW, 29 kW and 32 kW, respectively, for hotels, hospitals, administrative and public-school. The heat generation is ensured by a solar collector areas of 5 m², 7 m² and 10 m², respectively, for hotels, hospitals, administrative and public-school spaces, a storage tank of 2 m3 and a finned heat exchanger with 24 tubes. The finned tube bundles have been modelled and integrated into the system design via a Matlab code. The heating temperature is adjusted via two controllers to ensure a constant air temperature of 20°C during the heating periods.

  4. Radiation Belt Transport Driven by Solar Wind Dynamic Pressure Fluctuations

    Science.gov (United States)

    Kress, B. T.; Hudson, M. K.; Ukhorskiy, A. Y.; Mueller, H.

    2012-12-01

    The creation of the Earth's outer zone radiation belts is attributed to earthward transport and adiabatic acceleration of electrons by drift-resonant interactions with electromagnetic fluctuations in the magnetosphere. Three types of radial transport driven by solar wind dynamic pressure fluctuations that have been identified are: (1) radial diffusion [Falthammer, 1965], (2) significant changes in the phase space density radial profile due to a single or few ULF drift-resonant interactions [Ukhorskiy et al., 2006; Degeling et al., 2008], and (3) shock associated injections of radiation belt electrons occurring in less than a drift period [Li et al., 1993]. A progress report will be given on work to fully characterize different forms of radial transport and their effect on the Earth's radiation belts. The work is being carried out by computing test-particle trajectories in electric and magnetic fields from a simple analytic ULF field model and from global MHD simulations of the magnetosphere. Degeling, A. W., L. G. Ozeke, R. Rankin, I. R. Mann, and K. Kabin (2008), Drift resonant generation of peaked relativistic electron distributions by Pc 5 ULF waves, textit{J. Geophys. Res., 113}, A02208, doi:10.1029/2007JA012411. Fälthammar, C.-G. (1965), Effects of Time-Dependent Electric Fields on Geomagnetically Trapped Radiation, J. Geophys. Res., 70(11), 2503-2516, doi:10.1029/JZ070i011p02503. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake (1993), Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, textit{Geophys. Res. Lett., 20}(22), 2423-2426, doi:10.1029/93GL02701. Ukhorskiy, A. Y., B. J. Anderson, K. Takahashi, and N. A. Tsyganenko (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, textit{Geophys. Res. Lett., 33}(6), L06111, doi:10.1029/2005GL024380.

  5. Computation of the Fluid and Optical Fields About the Stratospheric Observatory for Infrared Astronomy (SOFIA) and the Coupling of Fluids, Dynamics, and Control Laws on Parallel Computers

    Science.gov (United States)

    Atwood, Christopher A.

    1993-01-01

    The June 1992 to May 1993 grant NCC-2-677 provided for the continued demonstration of Computational Fluid Dynamics (CFD) as applied to the Stratospheric Observatory for Infrared Astronomy (SOFIA). While earlier grant years allowed validation of CFD through comparison against experiments, this year a new design proposal was evaluated. The new configuration would place the cavity aft of the wing, as opposed to the earlier baseline which was located immediately aft of the cockpit. This aft cavity placement allows for simplified structural and aircraft modification requirements, thus lowering the program cost of this national astronomy resource. Three appendices concerning this subject are presented.

  6. The Second Flight of the Sunrise Balloon-borne Solar Observatory: Overview of Instrument Updates, the Flight, the Data, and First Results

    Energy Technology Data Exchange (ETDEWEB)

    Solanki, S. K.; Riethmüller, T. L.; Barthol, P.; Danilovic, S.; Deutsch, W.; Doerr, H.-P.; Feller, A.; Gandorfer, A.; Germerott, D.; Gizon, L.; Grauf, B.; Heerlein, K.; Hirzberger, J.; Kolleck, M.; Lagg, A.; Meller, R.; Tomasch, G.; Noort, M. van [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Rodríguez, J. Blanco; Blesa, J. L. Gasent, E-mail: solanki@mps.mpg.de [Grupo de Astronomía y Ciencias del Espacio, Universidad de Valencia, E-46980 Paterna, Valencia (Spain); and others

    2017-03-01

    The Sunrise balloon-borne solar observatory, consisting of a 1 m aperture telescope that provides a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in 2013 June. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg ii k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000 Å after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR 11768 observed relatively close to disk center is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500 G, and while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.

  7. Charge carrier dynamics in thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Strothkaemper, Christian

    2013-06-24

    This work investigates the charge carrier dynamics in three different technological approaches within the class of thin film solar cells: radial heterojunctions, the dye solar cell, and microcrystalline CuInSe{sub 2}, focusing on charge transport and separation at the electrode, and the relaxation of photogenerated charge carriers due to recombination and energy dissipation to the phonon system. This work relies mostly on optical-pump terahertz-probe (OPTP) spectroscopy, followed by transient absorption (TA) and two-photon photoemission (2PPE). The charge separation in ZnO-electrode/In{sub 2}S{sub 3}-absorber core/shell nanorods, which represent a model system of a radial heterojunction, is analyzed by OPTP. It is concluded, that the dynamics in the absorber are determined by multiple trapping, which leads to a dispersive charge transport to the electrode that lasts over hundreds of picoseconds. The high trap density on the order of 10{sup 19}/cm{sup 3} is detrimental for the injection yield, which exhibits a decrease with increasing shell thickness. The heterogeneous electron transfer from a series of model dyes into ZnO proceeds on a time-scale of 200 fs. However, the photoconductivity builds up just on a 2-10 ps timescale, and 2PPE reveals that injected electrons are meanwhile localized spatially and energetically at the interface. It is concluded that the injection proceeds through adsorbate induced interface states. This is an important result because the back reaction from long lived interface states can be expected to be much faster than from bulk states. While the charge transport in stoichiometric CuInSe{sub 2} thin films is indicative of free charge carriers, CuInSe{sub 2} with a solar cell grade composition (Cu-poor) exhibits signs of carrier localization. This detrimental effect is attributed to a high density of charged defects and a high degree of compensation, which together create a spatially fluctuating potential that inhibits charge transport. On

  8. A search for matter enhanced neutrino oscillations through measurements of day and night solar neutrino fluxes at the Sudbury Neutrino Observatory

    Science.gov (United States)

    Miknaitis, Kathryn Kelly Schaffer

    The Sudbury Neutrino Observatory (SNO) is a heavy-water Cherenkov detector designed to study 8B neutrinos from the sun. Through the charged-current (CC) and neutral-current (NC) reactions of neutrinos on deuterium, SNO separately determines the flux of electron neutrinos and the flux of all active flavors of solar 8B neutrinos. SNO is also sensitive to the elastic scattering (ES) of neutrinos on electrons in the heavy water. Measurements of the CC and NC rates in SNO have conclusively demonstrated solar neutrino flavor change. This flavor change is believed to be caused by matter-enhanced oscillations in the sun, through the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Matter effects could also change the flavor composition of neutrinos that traverse the earth. A comparison of the day and night measured CC flux at SNO directly tests for the MSW effect and contributes to constraints on neutrino oscillation parameters in the MSW model. We perform measurements of the day and night neutrino fluxes using data from the second phase of SNO, in which salt (NaCl) was added to the heavy water to enhance sensitivity to the NC reaction. Better discrimination between CC and NC events in the salt phase allows the fluxes to be determined without constraining the neutrino energy spectrum. The day-night asymmetry in the CC flux measured in this model-independent analysis is ACC = [-5.6 +/- 7.4(stat.) +/- 5.3(syst.)]%, where the asymmetry is defined as the difference between the night and day values divided by their average. The asymmetries in the NC and ES fluxes are ANC = [4.2 +/- 8.6(stat.) +/- 7.2(syst.)]%, and AES = (14.6 +/- 19.8(stat.) +/- 3.3(syst.)]%. The neutral current asymmetry is expected to be zero assuming standard neutrino oscillations. When we constrain it to be zero, we obtain ACC = [-3.7 +/- 6.3(stat.) +/- 3.2(syst.)]% and AES = [15.3 +/- 19.8(stat.) +/- 3.0(syst.)]%. The day and night energy spectra from the CC reaction have been measured and show no evidence for

  9. The Sudbury Neutrino Observatory

    International Nuclear Information System (INIS)

    Norman, E.B.; Chan, Y.D.; Garcia, A.; Lesko, K.T.; Smith, A.R.; Stokstad, R.G.; Zlimen, I.; Evans, H.C.; Ewan, G.T.; Hallin, A.; Lee, H.W.; Leslie, J.R.; MacArthur, J.D.; Mak, H.B.; McDonald, A.B.; McLatchie, W.; Robertson, B.C.; Skensved, P.; Sur, B.; Jagam, P.; Law, J.; Ollerhead, R.W.; Simpson, J.J.; Wang, J.X.; Tanner, N.W.; Jelley, N.A.; Barton, J.C.; Doucas, G.; Hooper, E.W.; Knox, A.B.; Moorhead, M.E.; Omori, M.; Trent, P.T.; Wark, D.L.

    1992-11-01

    Two experiments now in progress have reported measurements of the flux of high energy neutrinos from the Sun. Since about 1970, Davis and his co-workers have been using a 37 Cl-based detector to measure the 7 Be and 8 B solar neutrino flux and have found it to be at least a factor of three lower than that predicted by the Standard Solar Model (SSM). The Kamiokande collaborations has been taking data since 1986 using a large light-water Cerenkov detector and have confirmed that the flux is about two times lower than predicted. Recent results from the SAGE and GALLEX gallium-based detectors show that there is also a deficit of the low energy pp solar neutrinos. These discrepancies between experiment and theory could arise because of inadequacies in the theoretical models of solar energy generation or because of previously unobserved properties of neutrinos. The Sudbury Neutrino Observatory (SNO) will provide the information necessary to decide which of these solutions to the ''solar neutrino problem'' is correct

  10. AUTOMATIC DETECTION ALGORITHM OF DYNAMIC PRESSURE PULSES IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi; Xie, Yanqiong; Li, Huijun; Xu, Xiaojun

    2015-01-01

    Dynamic pressure pulses (DPPs) in the solar wind are a significant phenomenon closely related to the solar-terrestrial connection and physical processes of solar wind dynamics. In order to automatically identify DPPs from solar wind measurements, we develop a procedure with a three-step detection algorithm that is able to rapidly select DPPs from the plasma data stream and simultaneously define the transition region where large dynamic pressure variations occur and demarcate the upstream and downstream region by selecting the relatively quiet status before and after the abrupt change in dynamic pressure. To demonstrate the usefulness, efficiency, and accuracy of this procedure, we have applied it to the Wind observations from 1996 to 2008 by successfully obtaining the DPPs. The procedure can also be applied to other solar wind spacecraft observation data sets with different time resolutions

  11. The Observatory as Laboratory: Spectral Analysis at Mount Wilson Observatory

    Science.gov (United States)

    Brashear, Ronald

    2018-01-01

    This paper will discuss the seminal changes in astronomical research practices made at the Mount Wilson Observatory in the early twentieth century by George Ellery Hale and his staff. Hale’s desire to set the agenda for solar and stellar astronomical research is often described in terms of his new telescopes, primarily the solar tower observatories and the 60- and 100-inch telescopes on Mount Wilson. This paper will focus more on the ancillary but no less critical parts of Hale’s research mission: the establishment of associated “physical” laboratories as part of the observatory complex where observational spectral data could be quickly compared with spectra obtained using specialized laboratory equipment. Hale built a spectroscopic laboratory on the mountain and a more elaborate physical laboratory in Pasadena and staffed it with highly trained physicists, not classically trained astronomers. The success of Hale’s vision for an astronomical observatory quickly made the Carnegie Institution’s Mount Wilson Observatory one of the most important astrophysical research centers in the world.

  12. DYNAMICS OF A SOLAR PROMINENCE TORNADO OBSERVED BY SDO/AIA ON 2012 NOVEMBER 7–8

    Energy Technology Data Exchange (ETDEWEB)

    Mghebrishvili, Irakli; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Ramishvili, Giorgi [Abastumani Astrophysical Observatory at Ilia State University, University St. 2, Tbilisi, Georgia (United States); Shergelashvili, Bidzina [Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz (Austria); Veronig, Astrid [IGAM-Kanzelhöhe Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Poedts, Stefaan, E-mail: teimuraz.zaqarashvili@oeaw.ac.at [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

    2015-09-10

    We study the detailed dynamics of a solar prominence tornado using time series of 171, 304, 193, and 211 Å spectral lines obtained by the Solar Dynamics Observatory/Atmospheric Imaging Assembly during 2012 November 7–8. The tornado first appeared at 08:00 UT, November 07, near the surface, gradually rose upwards with the mean speed of ∼1.5 km s{sup −1} and persisted over 30 hr. Time–distance plots show two patterns of quasi-periodic transverse displacements of the tornado axis with periods of 40 and 50 minutes at different phases of the tornado evolution. The first pattern occurred during the rising phase and can be explained by the upward motion of the twisted tornado. The second pattern occurred during the later stage of evolution when the tornado already stopped rising and could be caused either by MHD kink waves in the tornado or by the rotation of two tornado threads around a common axis. The later hypothesis is supported by the fact that the tornado sometimes showed a double structure during the quasi-periodic phase. 211 and 193 Å spectral lines show a coronal cavity above the prominence/tornado, which started expansion at ∼13:00 UT and continuously rose above the solar limb. The tornado finally became unstable and erupted together with the corresponding prominence as coronal mass ejection (CME) at 15:00 UT, November 08. The final stage of the evolution of the cavity and the tornado-related prominence resembles the magnetic breakout model. On the other hand, the kink instability may destabilize the twisted tornado, and consequently prominence tornadoes can be used as precursors for CMEs.

  13. Structure and Dynamics of the Quiet Solar Chromosphere

    Science.gov (United States)

    Kalkofen, Wolfgang

    2002-04-01

    The grant supported research on the structure of the quiet, nonmagnetic chromosphere and on wave excitation and propagation in both the nonmagnetic chromosphere and the magnetic network. The work on the structure of the chromosphere culminated in the recognition that between two competing views of the solar chromosphere, older models by Avrett and collaborators (referred to as VAL) and the newer, dynamical model by Carlsson & Stein (referred to as CS), the clear decision is in favor of the older models, and this in spite of the evident lack of physics, which does not include wave motion and oscillations. The contrast between the static VAL models and the dynamical CS model can be stated most succinctly by comparing the temperature variation implied by the VAL models and the temperature fluctuations of the CS model, which are, respectively, of the order of 10% for the VAL model (at heights where hydrogen is 50% ionized) and a factor of 10 (at the upper boundary of their chromospheric model). The huge fluctuations of the CS model have never been observed, whereas the smaller temperature variations of the VAL models are consistent with ground-based and space-based observations. While it should be obvious which model describes the Sun and which one fails, the case is far from settled in the minds of solar physicists. Thus, much educational work remains to be done and, of course, more research to develop arguments that make the case more convincing. The research on waves and oscillations has been based on a unified theory of excitation of acoustic waves in the field-free atmosphere and of transverse and longitudinal waves in magnetic flux tubes located in the magnetic network by noting, first, that impulsive excitation of all these waves in gravitationally stratified media leads to oscillations at the respective cutoff frequencies and, second, that the observed oscillation frequencies in the nonmagnetic and magnetic parts of the chromosphere match corresponding cutoff

  14. Sudbury neutrino observatory proposal

    International Nuclear Information System (INIS)

    Ewan, G.T.; Evans, H.C.; Lee, H.W.

    1987-10-01

    This report is a proposal by the Sudbury Neutrino Observatory (SNO) collaboration to develop a world class laboratory for neutrino astrophysics. This observatory would contain a large volume heavy water detector which would have the potential to measure both the electron-neutrino flux from the sun and the total solar neutrino flux independent of neutrino type. It will therefore be possible to test models of solar energy generation and, independently, to search for neutrino oscillations with a sensitivity many orders of magnitude greater than that of terrestrial experiments. It will also be possible to search for spectral distortion produced by neutrino oscillations in the dense matter of the sun. Finally the proposed detector would be sensitive to neutrinos from a stellar collapse and would detect neutrinos of all types thus providing detailed information on the masses of muon- and tau-neutrinos. The neutrino detector would contain 1000 tons of D20 and would be located more than 2000 m below ground in the Creighton mine near Sudbury. The operation and performance of the proposed detector are described and the laboratory design is presented. Construction schedules and responsibilities and the planned program of technical studies by the SNO collaboration are outlined. Finally, the total capital cost is estimated to be $35M Canadian and the annual operating cost, after construction, would be $1.8 M Canadian, including the insurance costs of the heavy water

  15. Frontier of solar observation. Solar activity observed by 'HINODE' mission

    International Nuclear Information System (INIS)

    Watanabe, Tetsuya

    2008-01-01

    After launched in September 2006, solar observation satellite 'HINODE' has been a solar observatory on orbit with the scientific instruments well operated and its continuous observation was conducted steadily on almost all solar atmospheres from photosphere to corona. 'HINODE' was equipped with the solar optical telescope, extreme-ultraviolet imaging spectrometer and x-ray telescope and aimed at clarifying the mystery of solar physics related with coronal heating and magnetic reconnection. Present state of 'HINODE' was described from observations made in initial observation results, which have made several discoveries, such as Alfven waves in the corona, unexpected dynamics in the chromosphere and photosphere, continuous outflowing plasma as a possible source of solar wind, and fine structures of magnetic field in sunspots and solar surface. (T. Tanaka)

  16. The role of helioseismology in the knowledge of the solar interior dynamics and in the solar neutrino puzzle

    International Nuclear Information System (INIS)

    Couvidat, Sebastien

    2002-01-01

    This dissertation focuses on the solar interior dynamics and the neutrino puzzle, using helioseismology and more specifically the SoHO/GOLF data as a tool to probe the radiative interior of the Sun. We show how helioseismology gives us a direct access to the deep-layer dynamics through the solar rotation profile. Our data favor a decrease of the rotation velocity near the nuclear core. This can be used to constrain the angular momentum distribution processes, and to set an upper bound on the intensity of the magnetic field in this part of the Sun. The search for gravity modes with an original method is another topic of this dissertation. Several candidates are detected that need now to be confirmed. Gravity modes will give us a precious insight into the solar core structure and dynamics. We also use the stellar evolution code CESAM. By combining seismic data and solar modelling, we produce solar seismic models. The neutrino flux predictions from these models are partly derived on an observational basis. The comparison of these fluxes with the SNO results gives the solution to the solar neutrino puzzle: neutrinos have masses and they oscillate between different lepton flavors. This explains the deficit of detections observed since the sixties. We also work on the internal magnetic fields that take part to the dynamic processes. In particular, we start to study the impact of these fields on the neutrino production and transport. Finally, we reach the limits of the 1D stellar codes: they cannot take into account the dynamic processes efficiently. This justifies the current development of 2D or 3D codes. (author) [fr

  17. Dynamical evolution of small bodies in the Solar System

    Science.gov (United States)

    Jacobson, Seth A.

    2012-05-01

    This thesis explores the dynamical evolution of small bodies in the Solar System. It focuses on the asteroid population but parts of the theory can be applied to other systems such as comets or Kuiper Belt objects. Small is a relative term that refers to bodies whose dynamics can be significantly perturbed by non-gravitational forces and tidal torques on timescales less than their lifetimes (for instance the collisional timescale in the Main Belt asteroid population or the sun impact timescale for the near-Earth asteroid population). Non-gravitational torques such as the YORP effect can result in the active endogenous evolution of asteroid systems; something that was not considered more than twenty years ago. This thesis is divided into three independent studies. The first explores the dynamics of a binary systems immediately after formation from rotational fission. The rotational fission hypothesis states that a rotationally torqued asteroid will fission when the centrifugal accelerations across the body exceed gravitational attraction. Asteroids must have very little or no tensile strength for this to occur, and are often referred to as "rubble piles.'' A more complete description of the hypothesis and the ensuing dynamics is provided there. From that study a framework of asteroid evolution is assembled. It is determined that mass ratio is the most important factor for determining the outcome of a rotational fission event. Each observed binary morphology is tied to this evolutionary schema and the relevant timescales are assessed. In the second study, the role of non-gravitational and tidal torques in binary asteroid systems is explored. Understanding the competition between tides and the YORP effect provides insight into the relative abundances of the different binary morphologies and the effect of planetary flybys. The interplay between tides and the BYORP effect creates dramatic evolutionary pathways that lead to interesting end states including stranded

  18. Evaluating the relationships between solar-induced chlorophyll fluorescence from Orbiting Carbon Observatory-2 and gross primary productivity from eddy covariance flux towers

    Science.gov (United States)

    Li, X.; Xiao, J.; He, B.

    2017-12-01

    Solar-induced chlorophyll fluorescence (SIF) opens a new perspective on the monitoring of vegetation photosynthesis from space, and has been recently used to estimate gross primary productivity (GPP). However, previous studies on SIF were mainly based on satellite observations from the Greenhouse Gases Observing Satellite (GOSAT) and Global Ozone Monitoring Experiment-2 (GOME-2), and the evaluation of these coarse-resolution SIF measurements using GPP derived from eddy covariance (EC) flux towers has been hindered by the scale mismatch between satellite and tower footprints. We use new far-red SIF observations from the Orbiting Carbon Observatory-2 (OCO-2) satellite with much finer spatial resolution and GPP data from EC flux towers from 2014 to 2016 to examine the relationship between GPP and SIF for temperate forests. The OCO-2 SIF tracked tower GPP fairly well, and had strong correlation with tower GPP at both retrieval bands (757nm and 771nm) and both instantaneous (mid-day) and daily timescales. Daily SIF at 757nm (SIF757) exhibited much stronger correlation with tower GPP compared to MODIS enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) derived from either Terra or Aqua and had a similarly strong relationship as EVI based on the bidirectional reflectance distribution function (BRDF) corrected reflectance product (Terra+Aqua). Absorbed photosynthetically active radiation (APAR) explained 85% of the variance in SIF757, while the product of APAR and two environmental scalars - fTmin and fVPD (representing minimum temperature stress and water stress) explained slightly higher variance (92%) in SIF757. This suggests that SIF mainly depends on APAR and also contains information on light use efficiency (LUE) reflecting environmental stresses and physiological or biochemical variations of vegetation. The hyperbolic model based on SIF757 estimated GPP well (R2=0.81, pmodel - the MODSI GPP algorithm. Our findings demonstrate the strong

  19. Cosmic Rays and Dynamical Meteorology, 2. Snow Effect In Different Multiplicities According To Neutron Monitor Data of Emilio Segre' Observatory

    Science.gov (United States)

    Dorman, L. I.; Iucci, N.; Pustil'Nik, L. A.; Sternlieb, A.; Villoresi, G.; Zukerman, I. G.

    On the basis of cosmic ray hourly data obtained by NM of Emilio Segre' Observatory (hight 2025 m above s.l., cut-off rigidity for vertical direction 10.8 GV) we determine the snow effect in CR for total neutron intensity and for multiplicities m=1, m=2, m=3, m=4, m=5, m=6, and m=7. For comparison and excluding primary CR variations we use also hourly data on neutron multiplicities obtained by Rome NM (about sea level, cut-off rigidity 6.7 GV). In this paper we will analize effects of snow in periods from 4 January 2000 to 15 April 2000 with maximal absorption effect about 5%, and from 21 December 2000 up to 31 March 2001 with maximal effect 13% in the total neu- tron intensity. We use the periods without snow to determine regeression coefficients between primary CR variations observed by NM of Emilio Segre' Observatory, and by Rome NM. On the basis of obtained results we develop a method to correct data on snow effect by using several NM hourly data. On the basis of our data we estimate the accuracy with what can be made correction of NM data of stations where the snow effect can be important.

  20. Effects of solar activity in the middle atmosphere dynamical regime over Eastern Siberia, USSR

    Science.gov (United States)

    Gaidukov, V. A.; Kazimirovsky, E. S.; Zhovty, E. I.; Chernigovskaya, M. A.

    1989-01-01

    Lower thermospheric (90 to 120 km) wind data was acquired by ground based spaced-receiver method (HF, LF) near Irkutsk (52 deg N, 104 deg E). There is interrelated solar and meteorological control of lower thermosphere dynamics. Some features of solar control effects on the wind parameters are discussed.

  1. The debris disc of solar analogue τ Ceti: Herschel observations and dynamical simulations of the proposed multiplanet system

    NARCIS (Netherlands)

    Lawler, S.M.; Di Francesco, J.; Kennedy, G.M.; Sibthorpe, B.; Booth, M.; Vandenbussche, B.; Matthews, B.C.; Holland, W.S.; Greaves, J.; Wilner, D.J.; Tuomi, M.; Blommaert, J.A.D.L.; de Vries, B.L.; Dominik, C.; Fridlund, M.; Gear, W.; Heras, A.M.; Ivison, R.; Olofsson, G.

    2014-01-01

    τ Ceti is a nearby, mature G-type star very similar to our Sun, with a massive Kuiper Belt analogue and possible multiplanet system that has been compared to our Solar system. We present Herschel Space Observatory images of the debris disc, finding the disc is resolved at 70 μm and 160 μm, and

  2. On protection of freedom's solar dynamic radiator from the orbital debris environment. Part 2

    International Nuclear Information System (INIS)

    Rhatigan, J.L.

    1992-01-01

    In this paper, recent progress to better understand the environmental threat of micrometeoroid and space debris to the solar dynamic radiator for the Space Station Freedom power system is reported. The objective was to define a design which would perform to survivability requirements over the expected lifetime of the radiator. A previous paper described the approach developed to assess on-orbit survivability of the solar dynamic radiator due to micrometeoroid and space debris impacts. Preliminary analyses were presented to quantify the solar dynamic radiator survivability. These included the type of particle and particle population expected to defeat the radiator bumpering. Results of preliminary hypervelocity impact (HVI) testing performed on radiator panel samples were also presented. This paper presents results of a more extensive test program undertaken to further define the response of the solar dynamic radiator to HVI. Tests were conducted on representative radiator panels (under ambient, nonoperating conditions) over a range of particle size, particle density, impact angle, and impact velocity. Target parameters were also varied. Data indicate that analytical penetration predictions are conservative (i.e., pessimistic) for the specific configuration of the solar dynamic radiator. Test results are used to define more rigorously the solar dynamic radiator reliability with respect to HVI. Test data, analyses, and survivability results are presented

  3. ESO's Two Observatories Merge

    Science.gov (United States)

    2005-02-01

    , a unique instrument capable of measuring stellar radial velocities with an unsurpassed accuracy better than 1 m/s, making it a very powerful tool for the discovery of extra-solar planets. In addition, astronomers have also access to the 2.2-m ESO/MPG telescope with its Wide Field Imager camera. A new control room, the RITZ (Remote Integrated Telescope Zentrum), allows operating all three ESO telescopes at La Silla from a single place. The La Silla Observatory is also the first world-class observatory to have been granted certification for the International Organization for Standardization (ISO) 9001 Quality Management System. Moreover, the infrastructure of La Silla is still used by many of the ESO member states for targeted projects such as the Swiss 1.2-m Euler telescope and the robotic telescope specialized in the follow-up of gamma-ray bursts detected by satellites, the Italian REM (Rapid Eye Mount). In addition, La Silla is in charge of the APEX (Atacama Pathfinder Experiment) 12-m sub-millimetre telescope which will soon start routine observations at Chajnantor, the site of the future Atacama Large Millimeter Array (ALMA). The APEX project is a collaboration between the Max Planck Society in Germany, Onsala Observatory in Sweden and ESO. ESO also operates Paranal, home of the Very Large Telescope (VLT) and the VLT Interferometer (VLTI). Antu, the first 8.2-m Unit Telescope of the VLT, saw First Light in May 1998, starting what has become a revolution in European astronomy. Since then, the three other Unit Telescopes - Kueyen, Melipal and Yepun - have been successfully put into operation with an impressive suite of the most advanced astronomical instruments. The interferometric mode of the VLT (VLTI) is also operational and fully integrated in the VLT data flow system. In the VLTI mode, one state-of-the-art instrument is already available and another will follow soon. With its remarkable resolution and unsurpassed surface area, the VLT is at the forefront of

  4. Multi-thermal dynamics and energetics of a coronal mass ejection in the low solar atmosphere

    Science.gov (United States)

    Hannah, I. G.; Kontar, E. P.

    2013-05-01

    Aims: The aim of this work is to determine the multi-thermal characteristics and plasma energetics of an eruptive plasmoid and occulted flare observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA). Methods: We study a 2010 Nov. 3 event (peaking at 12:20 UT in GOES soft X-rays) of a coronal mass ejection and occulted flare that demonstrates the morphology of a classic erupting flux rope. The high spatial and time resolution and six coronal channels of the SDO/AIA images allows the dynamics of the multi-thermal emission during the initial phases of eruption to be studied in detail. The differential emission measure is calculated, using an optimized version of a regularized inversion method, for each pixel across the six channels at different times, resulting in emission measure maps and movies in a variety of temperature ranges. Results: We find that the core of the erupting plasmoid is hot (8-11, 11-14 MK) with a similarly hot filamentary "stem" structure connecting it to the lower atmosphere, which could be interpreted as the current sheet in the flux rope model, though is wider than these models suggest. The velocity of the leading edge of the eruption is 597-664 km s-1 in the temperature range ≥3-4 MK and between 1029-1246 km s-1 for ≤2-3 MK. We estimate the density (in 11-14 MK) of the erupting core and stem during the impulsive phase to be about 3 × 109 cm-3, 6 × 109 cm-3, 9 × 108 cm-3 in the plasmoid core, stem, and surrounding envelope of material. This gives thermal energy estimates of 5 × 1029 erg, 1 × 1029 erg, and 2 × 1030 erg. The kinetic energy for the core and envelope is slightly lower. The thermal energy of the core and current sheet grows during the eruption, suggesting continuous influx of energy presumably via reconnection. Conclusions: The combination of the optimized regularized inversion method and SDO/AIA data allows the multi-thermal characteristics (i.e. velocity, density, and thermal energies) of the

  5. Heat receivers for solar dynamic space power systems

    Science.gov (United States)

    Perez-Davis, Marla Esther

    A review of state-of-the-art technology is presented and discussed for phase change materials. Some of the advanced solar dynamic designs developed as part of the Advanced Heat Receiver Conceptual Design Study performed for LeRC are discussed. The heat receivers are analyzed and several recommendations are proposed, including two new concepts. The first concept evaluated the effect of tube geometries inside the heat receiver. It was found that a triangular configuration would provide better heat transfer to the working fluid, although not necessarily with a reduction in receiver size. A sensible heat receiver considered in this study uses vapor grown graphite fiber-carbon (VGCF/C) composite as the thermal storage media and was designed for a 7 kW Brayton engine. The proposed heat receiver stores the required energy to power the system during eclipse in the VGCF/C composite. The heat receiver analysis was conducted through the Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA) software package. The proposed heat receiver compares well with other latent and advanced sensible heat receivers while avoiding the problems associated with latent heat storage salts and liquid metal heat pipes. The weight and size of the system can be optimized by changes in geometry and technology advances for this new material. In addition to the new concepts, the effect of atomic oxygen on several materials is reviewed. A test was conducted for atomic oxygen attack on boron nitride, which experienced a negligible mass loss when exposed to an atomic oxygen fluence of 5 x 10 exp 21 atoms/sq cm. This material could be used to substitute the graphite aperture plate of the heat receiver.

  6. Short-term solar irradiation forecasting based on Dynamic Harmonic Regression

    International Nuclear Information System (INIS)

    Trapero, Juan R.; Kourentzes, Nikolaos; Martin, A.

    2015-01-01

    Solar power generation is a crucial research area for countries that have high dependency on fossil energy sources and is gaining prominence with the current shift to renewable sources of energy. In order to integrate the electricity generated by solar energy into the grid, solar irradiation must be reasonably well forecasted, where deviations of the forecasted value from the actual measured value involve significant costs. The present paper proposes a univariate Dynamic Harmonic Regression model set up in a State Space framework for short-term (1–24 h) solar irradiation forecasting. Time series hourly aggregated as the Global Horizontal Irradiation and the Direct Normal Irradiation will be used to illustrate the proposed approach. This method provides a fast automatic identification and estimation procedure based on the frequency domain. Furthermore, the recursive algorithms applied offer adaptive predictions. The good forecasting performance is illustrated with solar irradiance measurements collected from ground-based weather stations located in Spain. The results show that the Dynamic Harmonic Regression achieves the lowest relative Root Mean Squared Error; about 30% and 47% for the Global and Direct irradiation components, respectively, for a forecast horizon of 24 h ahead. - Highlights: • Solar irradiation forecasts at short-term are required to operate solar power plants. • This paper assesses the Dynamic Harmonic Regression to forecast solar irradiation. • Models are evaluated using hourly GHI and DNI data collected in Spain. • The results show that forecasting accuracy is improved by using the model proposed

  7. Metrology of the Solar Spectral Irradiance at the Top Of Atmosphere in the Near Infrared using Ground Based Instruments. Final results of the PYR-ILIOS campaign (Mauna Loa Observatory, June-July 2016).

    Science.gov (United States)

    Cessateur, G.; Bolsée, D.; Pereira, N.; Sperfeld, P.; Pape, S.

    2017-12-01

    The availability of reference spectra for the Solar Spectral Irradiance (SSI) is important for the solar physics, the studies of planetary atmospheres and climatology. The near infrared (NIR) part of these spectra is of great interest for its main role for example, in the Earth's radiative budget. Until recently, some large and unsolved discrepancies (up to 10 %) were observed in the 1.6 μm region between space instruments, models and ground-based measurements. We designed a ground-based instrumentation for SSI measurements at the Top Of Atmosphere (TOA) through atmospheric NIR windows using the Bouguer-Langley technique. The main instrument is a double NIR spectroradiometer designed by Bentham (UK), radiometrically characterized at the Royal Belgian Institute for Space Aeronomy. It was absolute calibrated against a high-temperature blackbody as primary standard for spectral irradiance at the Physikalisch-Technische Bundesanstalt (Germany). The PYR-ILIOS campaign was carried out in June to July 2016 at the Mauna Loa Observatory (Hawaii, USA, 3396 m a.s.l.) follows the four-month IRESPERAD campaign which was carried out in the summer 2011 at the Izaña Atmospheric Observatory (Canary Islands, 2367 m a.s.l.). We present here the results of the 3'week PYR-ILIOS campaign and compare them with the ATLAS 3 spectrum as well as from recently reprocessed NIR solar spectra obtained with SOLAR/SOLSPEC on ISS and SCIAMACHY on ENVISAT. The uncertainty budget of the PYR-ILIOS results will be discussed.

  8. SOLAR SOURCES OF 3He-RICH SOLAR ENERGETIC PARTICLE EVENTS IN SOLAR CYCLE 24

    International Nuclear Information System (INIS)

    Nitta, Nariaki V.; Mason, Glenn M.; Wang, Linghua; Cohen, Christina M. S.; Wiedenbeck, Mark E.

    2015-01-01

    Using high-cadence EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 3 He-rich solar energetic particle events at ≲1 MeV nucleon −1 that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the solar sources is based on the association of 3 He-rich events with type III radio bursts and electron events as observed by Wind. The source locations are further verified in EUV images from the Solar and Terrestrial Relations Observatory, which provides information on solar activities in the regions not visible from the Earth. Based on AIA observations, 3 He-rich events are not only associated with coronal jets as emphasized in solar cycle 23 studies, but also with more spatially extended eruptions. The properties of the 3 He-rich events do not appear to be strongly correlated with those of the source regions. As in the previous studies, the magnetic connection between the source region and the observer is not always reproduced adequately by the simple potential field source surface model combined with the Parker spiral. Instead, we find a broad longitudinal distribution of the source regions extending well beyond the west limb, with the longitude deviating significantly from that expected from the observed solar wind speed

  9. Vortex, ULF wave and Aurora Observation after Solar Wind Dynamic Pressure Change

    Science.gov (United States)

    Shi, Q.

    2017-12-01

    Here we will summarize our recent study and show some new results on the Magnetosphere and Ionosphere Response to Dynamic Pressure Change/disturbances in the Solar Wind and foreshock regions. We study the step function type solar wind dynamic pressure change (increase/decrease) interaction with the magnetosphere using THEMIS satellites at both dayside and nightside in different geocentric distances. Vortices generated by the dynamic pressure change passing along the magnetopause are found and compared with model predictions. ULF waves and vortices are excited in the dayside and nightside plasma sheet when dynamic pressure change hit the magnetotail. The related ionospheric responses, such as aurora and TCVs, are also investigated. We compare Global MHD simulations with the observations. We will also show some new results that dayside magnetospheric FLRs might be caused by foreshock structures.Shi, Q. Q. et al. (2013), THEMIS observations of ULF wave excitation in the nightside plasma sheet during sudden impulse events, J. Geophys. Res. Space Physics, 118, doi:10.1029/2012JA017984. Shi, Q. Q. et al. (2014), Solar wind pressure pulse-driven magnetospheric vortices and their global consequences, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019551. Tian, A.M. et al.(2016), Dayside magnetospheric and ionospheric responses to solar wind pressure increase: Multispacecraft and ground observations, J. Geophys. Res., 121, doi:10.1002/2016JA022459. Shen, X.C. et al.(2015), Magnetospheric ULF waves with increasing amplitude related to solar wind dynamic pressure changes: THEMIS observations, J. Geophys. Res., 120, doi:10.1002/2014JA020913Zhao, H. Y. et al. (2016), Magnetospheric vortices and their global effect after a solar wind dynamic pressure decrease, J. Geophys. Res. Space Physics, 121, doi:10.1002/2015JA021646. Shen, X. C., et al. (2017), Dayside magnetospheric ULF wave frequency modulated by a solar wind dynamic pressure negative impulse, J. Geophys. Res

  10. A new Laplace transformation method for dynamic testing of solar collectors

    DEFF Research Database (Denmark)

    Kong, Weiqiang; Perers, Bengt; Fan, Jianhua

    2015-01-01

    A new dynamic method for solar collector testing is developed. It is characterized by using the Laplace transformation technique to solve the differential governing equation. The new method was inspired by the so called New Dynamic Method (NDM) (Amer E. et al (1999) [1]) but totally different....... By integration of the Laplace transformation technique with the Quasi Dynamic Test (QDT) model (Fischer S. et al (2004) [2]), the Laplace – QDT (L-QDT) model is derived. Two experimental methods are then introduced. One is the shielding method which needs to shield and un-shield solar collector continuously...

  11. Analysis of shadowing effects on MIR photovoltaic and solar dynamic power systems

    Science.gov (United States)

    Fincannon, James

    1995-01-01

    The NASA Lewis Research Center is currently working with RSC-Energia, the Russian Space Agency, and Allied Signal in developing a flight demonstration solar dynamic power system. This type of power system is dependent upon solar flux that is reflected and concentrated into a thermal storage system to provide the thermal energy input to a closed-cycle Brayton heat engine. The solar dynamic unit will be flown on the Russian Mir space station in anticipation of use on the International Space Station Alpha. By the time the power system is launched, the Mir will be a spatially complex configuration which will have, in addition to the three-gimbaled solar dynamic unit, eleven solar array wings that are either fixed or track the Sun along one axis and a variety or repositionable habitation and experiment modules. The proximity of arrays to modules creates a situation which makes it highly probable that there will be varying solar flux due to shadowing on the solar dynamic unit and some of the arrays throughout the orbit. Shadowing causes fluctuations in the power output from the arrays and the solar dynamic power system, thus reducing the energy capabilities of the spacecraft. An assessment of the capabilities of the power system under these conditions is an important part in influencing the design and operations of the spacecraft and predicting its energy performance. This paper describes the results obtained from using the Orbiting Spacecraft Shadowing Analysis Station program that was integrated into the Station Power Analysis for Capability Evaluation (SPACE) electrical power system computer program. OSSA allows one to consider the numerous complex factors for analyzing the shadowing effects on the electrical power system including the variety of spacecraft hardware geometric configurations, yearly and daily orbital variations in the vehicle attitude and orbital maneuvers (for communications coverage, payload pointing requirements and rendezvous/docking with other

  12. Instrument Correction and Dynamic Site Profile Validation at the Central United States Seismic Observatory, New Madrid Seismic Zone

    Science.gov (United States)

    Brengman, C.; Woolery, E. W.; Wang, Z.; Carpenter, S.

    2016-12-01

    The Central United States Seismic Observatory (CUSSO) is a vertical seismic array located in southwestern Kentucky within the New Madrid seismic zone. It is intended to describe the effects of local geology, including thick sediment overburden, on seismic-wave propagation, particularly strong-motion. The three-borehole array at CUSSO is composed of seismic sensors placed on the surface, and in the bedrock at various depths within the 585 m thick sediment overburden. The array's deep borehole provided a unique opportunity in the northern Mississippi embayment for the direct geological description and geophysical measurement of the complete late Cretaceous-Quaternary sediment column. A seven layer, intra-sediment velocity model is interpreted from the complex, inhomogeneous stratigraphy. The S- and P-wave sediment velocities range between 160 and 875 m/s and between 1000 and 2300 m/s, respectively, with bedrock velocities of 1452 and 3775 m/s, respectively. Cross-correlation and direct comparisons were used to filter out the instrument response and determine the instrument orientation, making CUSSO data ready for analysis, and making CUSSO a viable calibration site for other free-field sensors in the area. The corrected bedrock motions were numerically propagated through the CUSSO soil profile (transfer function) and compared, in terms of both peak acceleration and amplitude spectra, to the recorded surface observations. Initial observations reveal a complex spectral mix of amplification and de-amplification across the array, indicating the site effect in this deep sediment setting is not simply generated by the shallowest layers.

  13. Dynamical Changes Induced by the Solar Proton Events in October-November 2003

    Science.gov (United States)

    Jackman, C. H.; Roble, R. G.; Fleming, E. L.

    2006-05-01

    The very large solar storms in October-November 2003 caused solar proton events (SPEs) at the Earth and impacted the upper atmospheric polar cap regions. The Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Mode (TIME-GCM) was used to study the atmospheric dynamical influence of the solar protons that occurred in Oct-Nov 2003, the fourth largest period of SPEs measured in the past 40 years. The highly energetic solar protons caused ionization and changes in the electric field, which led to Joule heating of the mesosphere and lower thermosphere. This heating led to temperature increases up to 4K in the upper mesosphere. The solar proton-induced ionization, as well as dissociation processes, led to the production of odd hydrogen (HOx) and odd nitrogen (NOy). Substantial (>40%) short-lived ozone decreases followed these enhancements of HOx and NOy and led to a cooling of the mesosphere and upper stratosphere. This cooling led to temperature decreases up to 2.5K. The solar proton-caused temperature changes led to maximum meridional and zonal wind variations of +/- 2 m/s on background winds up to +/- 30 m/s. The solar proton-induced wind perturbations were computed to taper off over a period of several days past the SPEs. Solar cycle 23 was accompanied by ten very large SPEs between 1998 and 2005, along with numerous smaller events. These solar proton-driven atmospheric variations need to be carefully considered when examining other polar changes.

  14. Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

    Science.gov (United States)

    Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

    1991-01-01

    Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

  15. Solar Features - Solar Flares - Patrol

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  16. Conceptual definition of a technology development mission for advanced solar dynamic power systems

    Science.gov (United States)

    Migra, R. P.

    1986-01-01

    An initial conceptual definition of a technology development mission for advanced solar dynamic power systems is provided, utilizing a space station to provide a dedicated test facility. The advanced power systems considered included Brayton, Stirling, and liquid metal Rankine systems operating in the temperature range of 1040 to 1400 K. The critical technologies for advanced systems were identified by reviewing the current state of the art of solar dynamic power systems. The experimental requirements were determined by planning a system test of a 20 kWe solar dynamic power system on the space station test facility. These requirements were documented via the Mission Requirements Working Group (MRWG) and Technology Development Advocacy Group (TDAG) forms. Various concepts or considerations of advanced concepts are discussed. A preliminary evolutionary plan for this technology development mission was prepared.

  17. The ground testing of a 2 kWe solar dynamic space power system

    International Nuclear Information System (INIS)

    Calogeras, J.E.

    1992-01-01

    Over the past 25 years Space Solar Dynamic component development has advanced to the point where it is considered a leading candidate power source technology for the evolutionary phases of the Space Station Freedom (SSF) program. Selection of SD power was based on studies and analyses which indicated significant savings in life cycle costs, launch mass and EVA requirements were possible when the system is compared to more conventional photovoltaic/battery power systems. Issues associated with micro-gravity operation such as the behavior of the thermal energy storage materials are being addressed in other programs. This paper reports that a ground test of a 2 kWe solar dynamic system is being planned by the NASA Office of Aeronautics and Space Technology to address the integration issues. The test will be scalable up to 25 kWe, will be flight configured and will incorporate relevant features of the SSF Solar Dynamic Power Module design

  18. An improved dynamic test method for solar collectors

    DEFF Research Database (Denmark)

    Kong, Weiqiang; Wang, Zhifeng; Fan, Jianhua

    2012-01-01

    A comprehensive improvement of the mathematical model for the so called transfer function method is presented in this study. This improved transfer function method can estimate the traditional solar collector parameters such as zero loss coefficient and heat loss coefficient. Two new collector...... parameters t and mfCf are obtained. t is a time scale parameter which can indicate the heat transfer ability of the solar collector. mfCf can be used to calculate the fluid volume content in the solar collector or to validate the regression process by comparing it to the physical fluid volume content...... for the second-order differential term with 6–9min as the best averaging time interval. The measured and predicted collector power output of the solar collector are compared during a test of 13days continuously both for the ITF method and the QDT method. The maximum and averaging error is 53.87W/m2 and 5.22W/m2...

  19. Dynamic Modeling of the Solar Field in Parabolic Trough Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Lourdes A. Barcia

    2015-11-01

    Full Text Available Parabolic trough solar power plants use a thermal fluid to transfer thermal energy from solar radiation to a water-steam Rankine cycle in order to drive a turbine that, coupled to an electrical generator, produces electricity. These plants have a heat transfer fluid (HTF system with the necessary elements to transform solar radiation into heat and to transfer that thermal energy to the water-steam exchangers. In order to get the best possible performance in the Rankine cycle and, hence, in the thermal plant, it is necessary that the thermal fluid reach its maximum temperature when leaving the solar field (SF. Also, it is mandatory that the thermal fluid does not exceed the maximum operating temperature of the HTF, above which it degrades. It must be noted that the optimal temperature of the thermal fluid is difficult to obtain, since solar radiation can change abruptly from one moment to another. The aim of this document is to provide a model of an HTF system that can be used to optimize the control of the temperature of the fluid without interfering with the normal operation of the plant. The results obtained with this model will be contrasted with those obtained in a real plant.

  20. Dynamics of longitudinal-latitudinal asymmetry of solar activity at various solar cycle phases

    International Nuclear Information System (INIS)

    Baranov, D.G.; Vernova, E.S.; Grigoryan, M.S.; Tyasto, M.I.

    1995-01-01

    Solar activity longitudinal asymmetry in 1943-1984 was studied by means of the polar diagram technique. Longitudinal changes of the activity distribution for northern and southern hemispheres were considered separately. Heliolongitudinal asymmetry was compared with the first harmonic of the 27-days cosmic ray intensity variation and with phases of the Quasi-Biennial Oscillation. There is certain correspondence between the dominance of the asymmetry in one of the solar hemispheres and the phase of the Quasi-Biennial Oscillation. Correlation exists between the amplitude of the 27-days galactic cosmic ray variation and the phase of the Quasi-Biennial Oscillation. 8 refs.; 3 figs

  1. Sudbury Neutrino Observatory

    International Nuclear Information System (INIS)

    Beier, E.W.

    1992-03-01

    This document is a technical progress report on work performed at the University of Pennsylvania during the current year on the Sudbury Neutrino Observatory project. The motivation for the experiment is the measurement of neutrinos emitted by the sun. The Sudbury Neutrino Observatory (SNO) is a second generation dedicated solar neutrino experiment which will extend the results of our work with the Kamiokande II detector by measuring three reactions of neutrinos rather than the single reaction measured by the Kamiokande experiment. The collaborative project includes physicists from Canada, the United Kingdom, and the United States. Full funding for the construction of this facility was obtained in January 1990, and its construction is estimated to take five years. The motivation for the SNO experiment is to study the fundamental properties of neutrinos, in particular the mass and mixing parameters, which remain undetermined after decades of experiments in neutrino physics utilizing accelerators and reactors as sources of neutrinos. To continue the study of neutrino properties it is necessary to use the sun as a neutrino source. The long distance to the sun makes the search for neutrino mass sensitive to much smaller mass than can be studied with terrestrial sources. Furthermore, the matter density in the sun is sufficiently large to enhance the effects of small mixing between electron neutrinos and mu or tau neutrinos. This experiment, when combined with the results of the radiochemical 37 Cl and 71 Ga experiments and the Kamiokande II experiment, should extend our knowledge of these fundamental particles, and as a byproduct, improve our understanding of energy generation in the sun

  2. Private Observatories in South Africa

    Science.gov (United States)

    Rijsdijk, C.

    2016-12-01

    Descriptions of private observatories in South Africa, written by their owners. Positions, equipment descriptions and observing programmes are given. Included are: Klein Karoo Observatory (B. Monard), Cederberg Observatory (various), Centurion Planetary and Lunar Observatory (C. Foster), Le Marischel Observatory (L. Ferreira), Sterkastaaing Observatory (M. Streicher), Henley on Klip (B. Fraser), Archer Observatory (B. Dumas), Overbeek Observatory (A. Overbeek), Overberg Observatory (A. van Staden), St Cyprian's School Observatory, Fisherhaven Small Telescope Observatory (J. Retief), COSPAR 0433 (G. Roberts), COSPAR 0434 (I. Roberts), Weltevreden Karoo Observatory (D. Bullis), Winobs (M. Shafer)

  3. The applications of Complexity Theory and Tsallis Non-extensive Statistics at Solar Plasma Dynamics

    Science.gov (United States)

    Pavlos, George

    2015-04-01

    As the solar plasma lives far from equilibrium it is an excellent laboratory for testing complexity theory and non-equilibrium statistical mechanics. In this study, we present the highlights of complexity theory and Tsallis non extensive statistical mechanics as concerns their applications at solar plasma dynamics, especially at sunspot, solar flare and solar wind phenomena. Generally, when a physical system is driven far from equilibrium states some novel characteristics can be observed related to the nonlinear character of dynamics. Generally, the nonlinearity in space plasma dynamics can generate intermittent turbulence with the typical characteristics of the anomalous diffusion process and strange topologies of stochastic space plasma fields (velocity and magnetic fields) caused by the strange dynamics and strange kinetics (Zaslavsky, 2002). In addition, according to Zelenyi and Milovanov (2004) the complex character of the space plasma system includes the existence of non-equilibrium (quasi)-stationary states (NESS) having the topology of a percolating fractal set. The stabilization of a system near the NESS is perceived as a transition into a turbulent state determined by self-organization processes. The long-range correlation effects manifest themselves as a strange non-Gaussian behavior of kinetic processes near the NESS plasma state. The complex character of space plasma can also be described by the non-extensive statistical thermodynamics pioneered by Tsallis, which offers a consistent and effective theoretical framework, based on a generalization of Boltzmann - Gibbs (BG) entropy, to describe far from equilibrium nonlinear complex dynamics (Tsallis, 2009). In a series of recent papers, the hypothesis of Tsallis non-extensive statistics in magnetosphere, sunspot dynamics, solar flares, solar wind and space plasma in general, was tested and verified (Karakatsanis et al., 2013; Pavlos et al., 2014; 2015). Our study includes the analysis of solar plasma time

  4. Recent Advances in Heliogyro Solar Sail Structural Dynamics, Stability, and Control Research

    Science.gov (United States)

    Wilkie, W. Keats; Warren, Jerry E.; Horta, Lucas G.; Lyle, Karen H.; Juang, Jer-Nan; Gibbs, S. Chad; Dowell, Earl H.; Guerrant, Daniel V.; Lawrence, Dale

    2015-01-01

    Results from recent NASA sponsored research on the structural dynamics, stability, and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, and solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment. Recent results from terrestrial 1-g blade dynamics and control experiments on "rope ladder" membrane blade analogs, and small-scale in vacuo system identification experiments with hanging and spinning high-aspect ratio membranes will also be presented. A low-cost, rideshare payload heliogyro technology demonstration mission concept is used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, and is also described. Blade torsional dynamic response and control are also shown to be significantly improved through the use of edge stiffening structural features or inclusion of modest tip masses to increase centrifugal stiffening of the blade structure. An output-only system identification procedure suitable for on-orbit blade dynamics investigations is also developed and validated using ground tests of spinning sub-scale heliogyro blade models. Overall, analytical and experimental investigations to date indicate no intractable stability or control issues for the heliogyro solar sail concept.

  5. European Southern Observatory

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    Professor A. Blaauw, Director general of the European Southern Observatory, with George Hampton on his right, signs the Agreement covering collaboration with CERN in the construction of the large telescope to be installed at the ESO Observatory in Chile.

  6. Dynamic Simulation over Long Time Periods with 100% Solar Generation.

    Energy Technology Data Exchange (ETDEWEB)

    Concepcion, Ricky James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Elliott, Ryan Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    This project aimed to identify the path forward for dynamic simulation tools to accommodate these needs by characterizing the properties of power systems (with high PV penetration), analyzing how these properties affect dynamic simulation software, and offering solutions for potential problems.

  7. Dynamics and control of a solar collector system for near Earth object deflection

    International Nuclear Information System (INIS)

    Gong Shenping; Li Junfeng; Gao Yunfeng

    2011-01-01

    A solar collector system is a possible method using solar energy to deflect Earth-threatening near-Earth objects. We investigate the dynamics and control of a solar collector system including a main collector (MC) and secondary collector (SC). The MC is used to collect the sunlight to its focal point, where the SC is placed and directs the collected light to an asteroid. Both the relative position and attitude of the two collectors should be accurately controlled to achieve the desired optical path. First, the dynamical equation of the relative motion of the two collectors in the vicinity of the asteroid is modeled. Secondly, the nonlinear sliding-mode method is employed to design a control law to achieve the desired configuration of the two collectors. Finally, the deflection capability of this solar collector system is compared with those of the gravitational tractor and solar sail gravitational tractor. The results show that the solar collector is much more efficient with respect to deflection capability.

  8. Numerical investigation on thermal and fluid dynamic behaviors of solar chimney building systems

    International Nuclear Information System (INIS)

    Manca, O.; Nardini, S.; Romano, P.; Mihailov, E.

    2013-01-01

    Full text: Buildings as big energy-consuming systems require large amount of energy to operate. Globally, buildings are responsible for approximately 40% of total world annual energy consumption. Sustainable buildings with renewable energy systems are trying to operate independently without consumption of conventional resources. Renewable energy is a significant approach to reduce resource consumption in sustainable building. A solar chimney is essentially divided into two parts, one - the solar air heater (collector) and second - the chimney. Two configurations of solar chimney are usually used: vertical solar chimney with vertical absorber geometry, and roof solar chimney. For vertical solar chimney, vertical glass is used to gain solar heat. Designing a solar chimney includes height, width and depth of cavity, type of glazing, type of absorber, and inclusion of insulation or thermal mass. Besides these system parameters, other factors such as the location, climate, and orientation can also affect its performance. In this paper a numerical investigation on a prototypal solar chimney system integrated in a south facade of a building is presented. The analysis is carried out on a three-dimensional model in air flow and the governing equations are given in terms of k-s turbulence model. Two geometrical configurations are investigated: 1) a channel with vertical parallel walls and 2) a channel with principal walls one vertical and the other inclined. The problem is solved by means of the commercial code Ansys-Fluent and the results are performed for a uniform wall heat flux on the vertical wall is equal to 300 and 600 W/m2. Results are given in terms of wall temperature distributions, air velocity and temperature fields and transversal profiles in order to evaluate the differences between the two base configurations and thermal and fluid dynamic behaviors. Further, the ground effect on thermal performances is examined. key words: mathematical modeling, solar chimney

  9. Long-term influence of asteroids on planet longitudes and chaotic dynamics of the solar system

    Science.gov (United States)

    Woillez, E.; Bouchet, F.

    2017-11-01

    Over timescales much longer than an orbital period, the solar system exhibits large-scale chaotic behavior and can thus be viewed as a stochastic dynamical system. The aim of the present paper is to compare different sources of stochasticity in the solar system. More precisely we studied the importance of the long term influence of asteroids on the chaotic dynamics of the solar system. We show that the effects of asteroids on planets is similar to a white noise process, when those effects are considered on a timescale much larger than the correlation time τϕ ≃ 104 yr of asteroid trajectories. We computed the timescale τe after which the effects of the stochastic evolution of the asteroids lead to a loss of information for the initial conditions of the perturbed Laplace-Lagrange secular dynamics. The order of magnitude of this timescale is precisely determined by theoretical argument, and we find that τe ≃ 104 Myr. Although comparable to the full main-sequence lifetime of the sun, this timescale is considerably longer than the Lyapunov time τI ≃ 10 Myr of the solar system without asteroids. This shows that the external sources of chaos arise as a small perturbation in the stochastic secular behavior of the solar system, rather due to intrinsic chaos.

  10. Real-time isotope monitoring network at the Biosphere 2 Landscape Evolution Observatory resolves meter-to-catchment scale flow dynamics

    Science.gov (United States)

    Volkmann, T. H. M.; Van Haren, J. L. M.; Kim, M.; Harman, C. J.; Pangle, L.; Meredith, L. K.; Troch, P. A.

    2017-12-01

    Stable isotope analysis is a powerful tool for tracking flow pathways, residence times, and the partitioning of water resources through catchments. However, the capacity of stable isotopes to characterize catchment hydrological dynamics has not been fully exploited as commonly used methodologies constrain the frequency and extent at which isotopic data is available across hydrologically-relevant compartments (e.g. soil, plants, atmosphere, streams). Here, building upon significant recent developments in laser spectroscopy and sampling techniques, we present a fully automated monitoring network for tracing water isotopes through the three model catchments of the Landscape Evolution Observatory (LEO) at the Biosphere 2, University of Arizona. The network implements state-of-the-art techniques for monitoring in great spatiotemporal detail the stable isotope composition of water in the subsurface soil, the discharge outflow, and the atmosphere above the bare soil surface of each of the 330-m2 catchments. The extensive valving and probing systems facilitate repeated isotope measurements from a total of more than five-hundred locations across the LEO domain, complementing an already dense array of hydrometric and other sensors installed on, within, and above each catchment. The isotope monitoring network is operational and was leveraged during several months of experimentation with deuterium-labelled rain pulse applications. Data obtained during the experiments demonstrate the capacity of the monitoring network to resolve sub-meter to whole-catchment scale flow and transport dynamics in continuous time. Over the years to come, the isotope monitoring network is expected to serve as an essential tool for collaborative interdisciplinary Earth science at LEO, allowing us to disentangle changes in hydrological behavior as the model catchments evolve in time through weathering and colonization by plant communities.

  11. Solar Indices - Sunspot Numbers

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  12. Solar Indices - Plage Regions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  13. Experimental analysis and dynamic simulation of a novel high-temperature solar cooling system

    International Nuclear Information System (INIS)

    Buonomano, Annamaria; Calise, Francesco; D’Accadia, Massimo Dentice; Ferruzzi, Gabriele; Frascogna, Sabrina; Palombo, Adolfo; Russo, Roberto; Scarpellino, Marco

    2016-01-01

    Highlights: • The paper presents an innovative high temperature solar cooling system. • The system is based on novel flat-plate evacuated solar thermal collectors. • Results of an experimental campaign in Saudi Arabia are reported. • A dynamic simulation model and a detailed economic analyses are developed. • Results show that the collector and the system as a whole exhibit excellent performance. - Abstract: This paper presents experimental and numerical analyses of a novel high-temperature solar cooling system based on innovative flat-plate evacuated solar thermal collectors (SC). This is the first solar cooling system, including a double-effect absorption chiller, which is based on non-concentrating solar thermal collectors. The aim of the paper is prove the technical and economic feasibility of the system, also presenting a comparison with a conventional technology, based on concentrating solar thermal collectors. To this scope, an experimental setup has been installed in Saudi Arabia. Here, several measurement devices are installed in order to monitor and control all the thermodynamic parameters of the system. The paper presents some of the main results of this experimental campaign, showing temperatures, powers, energies and efficiencies for a selected period. Experimental results showed that collector peak efficiency is higher than 60%, whereas daily average efficiency is around 40%. This prototypal solar cooling system has been numerically analysed, developing a dynamic simulation model aiming at predicting system performance. For a representative operating period, numerical data were compared with the experimental one, showing an excellent accuracy of the model. A similar system, equipped with Parabolic Trough solar thermal collectors (PTC) was also simulated in order to compare the novel solar collectors with such reference technology. For both systems a detailed thermo-economic model has been implemented in order to perform such comparison also

  14. Real-time dynamic analysis for complete loop of direct steam generation solar trough collector

    International Nuclear Information System (INIS)

    Guo, Su; Liu, Deyou; Chu, Yinghao; Chen, Xingying; Shen, Bingbing; Xu, Chang; Zhou, Ling; Wang, Pei

    2016-01-01

    Highlights: • A nonlinear distribution parameter dynamic model has been developed. • Real-time local heat transfer coefficient and friction coefficient are adopted. • The dynamic behavior of the solar trough collector loop are simulated. • High-frequency chattering of outlet fluid flow are analyzed and modeled. • Irradiance disturbance at subcooled water region generates larger influence. - Abstract: Direct steam generation is a potential approach to further reduce the levelized electricity cost of solar trough. Dynamic modeling of the collector loop is essential for operation and control of direct steam generation solar trough. However, the dynamic behavior of fluid based on direct steam generation is complex because of the two-phase flow in the pipeline. In this work, a nonlinear distribution parameter model has been developed to model the dynamic behaviors of direct steam generation parabolic trough collector loops under either full or partial solar irradiance disturbance. Compared with available dynamic model, the proposed model possesses two advantages: (1) real-time local values of heat transfer coefficient and friction resistance coefficient, and (2) considering of the complete loop of collectors, including subcooled water region, two-phase flow region and superheated steam region. The proposed model has shown superior performance, particularly in case of sensitivity study of fluid parameters when the pipe is partially shaded. The proposed model has been validated using experimental data from Solar Thermal Energy Laboratory of University of New South Wales, with an outlet fluid temperature relative error of only 1.91%. The validation results show that: (1) The proposed model successfully outperforms two reference models in predicting the behavior of direct steam generation solar trough. (2) The model theoretically predicts that, during solar irradiance disturbance, the discontinuities of fluid physical property parameters and the moving back and

  15. Spin-cast bulk heterojunction solar cells: A dynamical investigation

    KAUST Repository

    Chou, Kang Wei

    2013-02-22

    Spin-coating is extensively used in the lab-based manufacture of organic solar cells, including most of the record-setting solution-processed cells. We report the first direct observation of photoactive layer formation as it occurs during spin-coating. The study provides new insight into mechanisms and kinetics of bulk heterojunction formation, which may be crucial for its successful transfer to scalable printing processes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Spin-cast bulk heterojunction solar cells: A dynamical investigation

    KAUST Repository

    Chou, Kang Wei; Yan, Buyi; Li, Ruipeng; Li, Erqiang; Zhao, Kui; Anjum, Dalaver H.; Alvarez, Steven; Gassaway, Robert; Biocca, Alan K.; Thoroddsen, Sigurdur T; Hexemer, Alexander; Amassian, Aram

    2013-01-01

    Spin-coating is extensively used in the lab-based manufacture of organic solar cells, including most of the record-setting solution-processed cells. We report the first direct observation of photoactive layer formation as it occurs during spin-coating. The study provides new insight into mechanisms and kinetics of bulk heterojunction formation, which may be crucial for its successful transfer to scalable printing processes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Space astrophysical observatory 'Orion-2'

    International Nuclear Information System (INIS)

    Gurzadyan, G.A.; Jarakyan, A.L.; Krmoyan, M.N.; Kashin, A.L.; Loretsyan, G.M.; Ohanesyan, J.B.

    1976-01-01

    Ultraviolet spectrograms of a large number of faint stars up to 13sup(m) were obtained in the wavelengths 2000-5000 A by means of the space observatory 'Orion-2' installed in the spaceship 'Soyuz-13' with two spacemen on board. The paper deals with a description of the operation modes of this observatory, the designs and basic schemes of the scientific and auxiliary device and the method of combining the work of the flight engineer and the automation system of the observatory itself. It also treats of the combination of the particular parts of 'Orion-2' observatory on board the spaceship and the measures taken to provide for its normal functioning in terms of the space flight. A detailed description is given of the optical, electrical and mechanical schemes of the devices - meniscus telescope with an objective prism, stellar diffraction spectrographs, single-coordinate and two-coordinate stellar and solar transducers, control panel, control systems, etc. The paper also provides the functional scheme of astronavigation, six-wheel stabilization, the design of mounting (assembling) the stabilized platform carrying the telescopes and the drives used in it. Problems relating to the observation program in orbit, the ballistic provision of initial data, and control of the operation of the observatory are also dealt with. In addition, the paper carries information of the photomaterials used, the methods of their energy calibration, standardization and the like. Matters of pre-start tests of apparatus, the preparation of the spacemen for conducting astronomical observations with the given devices, etc. are likewise dwelt on. The paper ends with a brief survey of the results obtained and the elaboration of the observed material. (Auth.)

  18. Evaluation of alternative phase change materials for energy storage in solar dynamic applications

    Science.gov (United States)

    Crane, R. A.; Dustin, M. O.

    1988-01-01

    The performance of fluoride salt and metallic thermal energy storage materials are compared in terms of basic performance as applied to solar dynamic power generation. Specific performance considerations include uniformity of cycle inlet temperature, peak cavity temperature, TES utilization, and system weights. Also investigated were means of enhancing the thermal conductivity of the salts and its effect on the system performance.

  19. Photoexcitation dynamics in solution-processed formamidinium lead iodide perovskite thin films for solar cell applications

    NARCIS (Netherlands)

    Fang, Hong-Hua; Wang, Feng; Adjokatse, Sampson; Zhao, Ni; Even, Jacky; Loi, Maria Antonietta

    Formamidinium lead iodide (FAPbI(3)) is a newly developed hybrid perovskite that potentially can be used in high-efficiency solution-processed solar cells. Here, the temperature-dependent dynamic optical properties of three types of FAPbI(3) perovskite films (fabricated using three different

  20. Charge transport and recombination dynamics in organic bulk heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Andreas

    2011-08-02

    The charge transport in disordered organic bulk heterojunction (BHJ) solar cells is a crucial process affecting the power conversion efficiency (PCE) of the solar cell. With the need of synthesizing new materials for improving the power conversion efficiency of those cells it is important to study not only the photophysical but also the electrical properties of the new material classes. Thereby, the experimental techniques need to be applicable to operating solar cells. In this work, the conventional methods of transient photoconductivity (also known as ''Time-of-Flight'' (TOF)), as well as the transient charge extraction technique of ''Charge Carrier Extraction by Linearly Increasing Voltage'' (CELIV) are performed on different organic blend compositions. Especially with the latter it is feasible to study the dynamics - i.e. charge transport and charge carrier recombination - in bulk heterojunction (BHJ) solar cells with active layer thicknesses of 100-200 nm. For a well performing organic BHJ solar cells the morphology is the most crucial parameter finding a trade-off between an efficient photogeneration of charge carriers and the transport of the latter to the electrodes. Besides the morphology, the nature of energetic disorder of the active material blend and its influence on the dynamics are discussed extensively in this work. Thereby, the material system of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C{sub 61}butyric acid methyl ester (PC{sub 61}BM) serves mainly as a reference material system. New promising donor or acceptor materials and their potential for application in organic photovoltaics are studied in view of charge dynamics and compared with the reference system. With the need for commercialization of organic solar cells the question of the impact of environmental conditions on the PCE of the solar cells raises. In this work, organic BHJ solar cells exposed to synthetic air for finite duration are

  1. Dynamical Changes Induced by the Very Large Solar Proton Events in October-November 2003

    Science.gov (United States)

    Jackman, Charles H.; Roble, Raymond G.

    2006-01-01

    The very large solar storms in October-November 2003 caused solar proton events (SPEs) at the Earth and impacted the upper atmospheric polar cap regions. The Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Mode (TIME-GCM) was used to study the atmospheric dynamical influence of the solar protons that occurred in Oct-Nov 2003, the fourth largest period of SPEs measured in the past 40 years. The highly energetic solar protons caused ionization and changes in the electric field, which led to Joule heating of the mesosphere and lower thermosphere. This heating led to temperature increases up to 4K in the upper mesosphere. The solar proton-induced ionization, as well as dissociation processes, led to the production of odd hydrogen (HO(x)) and odd nitrogen (NO(y)). Substantial (>40%) short-lived ozone decreases followed these enhancements of HO(x) and NO(y) and led to a cooling of the mesosphere and upper stratosphere. This cooling led to temperature decreases up to 2.5K. The solar proton-caused temperature changes led to maximum meridional and zonal wind variations of +/- 2 m/s on background winds up to +/- 30 m/s. The solar proton-induced wind perturbations were computed to taper off over a period of several days past the SPEs. Solar cycle 23 was accompanied by ten very large SPEs between 1998 and 2005, along with numerous smaller events. These solar proton-driven atmospheric variations need to be carefully considered when examining other polar changes.

  2. Solar Magnetic Phenomena Proceedings of the 3rd Summerschool and Workshop held at the Solar Observatory Kanzelhöhe, Kärnten, Austria, August 25 — September 5, 2003

    CERN Document Server

    Hanslmeier, Arnold; Messerotti, Mauro

    2005-01-01

    The book contains lecture papers and contributed papers on different aspects of magnetic phenomena in the solar atmosphere. The main topics addressed are the physics of solar flares, prominences, coronal mass ejections, magnetic helicity, high-energy radiation from the Sun, observations of the photosphere and chromosphere as well as highlights from the SOHO mission. The lecture papers provide a very valuable introduction and overview on recent developments in these fields of solar physics. The comprehensive lists of references at the end of each review enable the interested reader to go into more detail. The book is particularly useful for graduate students and young researchers working in solar physics.

  3. Collisional dynamics of perturbed particle disks in the solar system

    Science.gov (United States)

    Roberts, W. W.; Stewart, G. R.

    1987-01-01

    Investigations of the collisional evolution of particulate disks subject to the gravitational perturbation of a more massive particle orbiting within the disk are underway. Both numerical N-body simulations using a novel collision algorithm and analytical kinetic theory are being employed to extend our understanding of perturbed disks in planetary rings and during the formation of the solar system. Particular problems proposed for investigation are: (1) The development and testing of general criteria for a small moonlet to clear a gap and produce observable morphological features in planetary rings; (2) The development of detailed models of collisional damping of the wavy edges observed on the Encke division of Saturn's A ring; and (3) The determination of the extent of runaway growth of the few largest planetesimals during the early stages of planetary accretion.

  4. The Solar Dynamic Buffer Zone (SDBZ) curtain wall: Validation and design of a solar air collector curtain wall

    Science.gov (United States)

    Richman, Russell Corey

    Given the increases in both the environmental and economic costs of energy, there is a need to design and building more sustainable and low-energy building systems now. Curtain wall assemblies show great promise---the spandrel panels within them can be natural solar collectors. By using a Solar Dynamic Buffer Zone (SDBZ) in the spandrel cavity, solar energy can be efficiently gathered using the movement of air. There is a need for a numerical model capable of predicting performance of an SDBZ Curtain Wall system. This research designed, constructed and quantified a prototype SDBZ curtain wall system through by experimental testing in a laboratory environment. The laboratory experiments focussed on three main variables: air flow through the system, incoming radiation and collector surface type. Results from the experimental testing were used to validate a one-dimensional numerical model of the prototype. Results from this research show a SDBZ curtain wall system as an effective means of reducing building heating energy consumption through the preheating of incoming exterior ventilation air during the heating season in cold climates. The numerical model showed good correlation with experimental results at higher operating flows and at lower flows when using an apparent velocity at the heat transfer boundary layer. A seasonal simulation for Toronto, ON predicted energy savings of 205 kWh/m2 with an average seasonal efficiency of 28%. This is considered in the upper range when compared to other solar air collectors. Given the lack of published literature for similar systems, this research acts to introduce a simple, innovative approach to collect solar energy that would otherwise be lost to the exterior using already existing components within a curtain wall. Specifically, the research has provided: results from experiments and simulation, a first generation numerical model, aspects of design and construction of the SDBZ curtain wall and specific directions for further

  5. Closed Cycle Engine Program Used in Solar Dynamic Power Testing Effort

    Science.gov (United States)

    Ensworth, Clint B., III; McKissock, David B.

    1998-01-01

    NASA Lewis Research Center is testing the world's first integrated solar dynamic power system in a simulated space environment. This system converts solar thermal energy into electrical energy by using a closed-cycle gas turbine and alternator. A NASA-developed analysis code called the Closed Cycle Engine Program (CCEP) has been used for both pretest predictions and post-test analysis of system performance. The solar dynamic power system has a reflective concentrator that focuses solar thermal energy into a cavity receiver. The receiver is a heat exchanger that transfers the thermal power to a working fluid, an inert gas mixture of helium and xenon. The receiver also uses a phase-change material to store the thermal energy so that the system can continue producing power when there is no solar input power, such as when an Earth-orbiting satellite is in eclipse. The system uses a recuperated closed Brayton cycle to convert thermal power to mechanical power. Heated gas from the receiver expands through a turbine that turns an alternator and a compressor. The system also includes a gas cooler and a radiator, which reject waste cycle heat, and a recuperator, a gas-to-gas heat exchanger that improves cycle efficiency by recovering thermal energy.

  6. CORONAL DYNAMIC ACTIVITIES IN THE DECLINING PHASE OF A SOLAR CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Minhwan; Choe, G. S. [Department of Astronomy and Space Science, Kyung Hee University, Yongin 17104 (Korea, Republic of); Woods, T. N. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Hong, Sunhak, E-mail: gchoe@khu.ac.kr [School of Space Research, Kyung Hee University, Yongin 17104 (Korea, Republic of)

    2016-12-10

    It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this Letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low-latitude coronal hole (CH) areas, splitting and merging events of CHs, and coronal mass ejections (CMEs) detected by SOHO /LASCO C3 in solar cycle 23. Although the total CH area is at its maximum near the sunspot minimum, in which polar CHs prevail, it shows a comparable second maximum in the declining phase of the cycle, in which low-latitude CHs are dominant. The events of CH splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 CMEs are also overpopulated in the declining phase of the cycle. From these results we suggest that solar dynamic activities due to the horizontal surface motions of magnetic fluxes extend far in the declining phase of the sunspot cycle.

  7. CORONAL DYNAMIC ACTIVITIES IN THE DECLINING PHASE OF A SOLAR CYCLE

    International Nuclear Information System (INIS)

    Jang, Minhwan; Choe, G. S.; Woods, T. N.; Hong, Sunhak

    2016-01-01

    It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this Letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low-latitude coronal hole (CH) areas, splitting and merging events of CHs, and coronal mass ejections (CMEs) detected by SOHO /LASCO C3 in solar cycle 23. Although the total CH area is at its maximum near the sunspot minimum, in which polar CHs prevail, it shows a comparable second maximum in the declining phase of the cycle, in which low-latitude CHs are dominant. The events of CH splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 CMEs are also overpopulated in the declining phase of the cycle. From these results we suggest that solar dynamic activities due to the horizontal surface motions of magnetic fluxes extend far in the declining phase of the sunspot cycle.

  8. Prey-predator dynamics driven by the solar radiation - Part 1

    International Nuclear Information System (INIS)

    Sertorio, L.

    2000-01-01

    In this paper is studied a model ecosystem represented by two components: prey and predator. The predator feeds only on the prey, the prey, in turn, feeds on the solar radiation. In this scheme the two-species dynamics is no longer independent of the external physical conditions. Such independence was instead postulated in the Lotka-Volterra scheme. In this paper is considered the growth of the prey not unbounded (exponential), but logistic, where the saturation factor is governed by the available solar flux, more precisely by the percent of the solar flux that contains the photon frequencies which can drive the photosynthesis. In this way the solar flux represents the driving term of the dynamics, as it is expected in general for a realistic ecosystem. The system is asymptotically stable. The equilibrium values of the prey and predator numbers depend on several parameters. The system contains two nonlinear coupling terms and two coupling parameters. The dependence of the equilibrium point on the coupling parameters is studied in detail. According to this model, it can be defined a predator efficiency and a global solar efficiency. It is discussed the relationship between these two functions of the coupling parameters and the maximum value that the predator population can reach

  9. Solar system constraints on multifield theories of modified dynamics

    NARCIS (Netherlands)

    Sanders, R. H.

    2006-01-01

    Any viable theory of modified Newtonian dynamics (MOND) as modified gravity is likely to require fields in addition to the usual tensor field of General Relativity. For these theories, the MOND phenomenology emerges as an effective fifth force probably associated with a scalar field. Here, I

  10. A parametric study of a solar calcinator using computational fluid dynamics

    International Nuclear Information System (INIS)

    Fidaros, D.K.; Baxevanou, C.A.; Vlachos, N.S.

    2007-01-01

    In this work a horizontal rotating solar calcinator is studied numerically using computational fluid dynamics. The specific solar reactor is a 10 kW model designed and used for efficiency studies. The numerical model is based on the solution of the Navier-Stokes equations for the gas flow, and on Lagrangean dynamics for the discrete particles. All necessary mathematical models were developed and incorporated into a computational fluid dynamics model with the influence of turbulence simulated by a two-equation (RNG k-ε) model. The efficiency of the reactor was calculated for different thermal inputs, feed rates, rotational speeds and particle diameters. The numerically computed degrees of calcination compared well with equivalent experimental results

  11. Dynamic modeling and sensitivity analysis of solar thermal energy conversion systems

    Science.gov (United States)

    Hamilton, C. L.

    1977-01-01

    Since the energy input to solar thermal conversion systems is both time variant and probabilistic, it is unlikely that simple steady-state methods for estimating lifetime performance will provide satisfactory results. The work described here uses dynamic modeling to begin identifying what must be known about input radiation and system dynamic characteristics to estimate performance reliably. Daily operation of two conceptual solar energy systems was simulated under varying operating strategies with time-dependent radiation intensity ranging from smooth input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours. Integrated daily system output and efficiency were functions of both level and dynamic characteristics of insolation. Sensitivity of output to changes in total input was greater than one.

  12. Comparative analyses on dynamic performances of photovoltaic–thermal solar collectors integrated with phase change materials

    International Nuclear Information System (INIS)

    Su, Di; Jia, Yuting; Alva, Guruprasad; Liu, Lingkun; Fang, Guiyin

    2017-01-01

    Highlights: • The dynamic model of photovoltaic–thermal collector with phase change material was developed. • The performances of photovoltaic–thermal collector are performed comparative analyses. • The performances of photovoltaic–thermal collector with phase change material were evaluated. • Upper phase change material mode can improve performances of photovoltaic–thermal collector. - Abstract: The operating conditions (especially temperature) of photovoltaic–thermal solar collectors have significant influence on dynamic performance of the hybrid photovoltaic–thermal solar collectors. Only a small percentage of incoming solar radiation can be converted into electricity, and the rest is converted into heat. This heat leads to a decrease in efficiency of the photovoltaic module. In order to improve the performance of the hybrid photovoltaic–thermal solar collector, we performed comparative analyses on a hybrid photovoltaic–thermal solar collector integrated with phase change material. Electrical and thermal parameters like solar cell temperature, outlet temperature of air, electrical power, thermal power, electrical efficiency, thermal efficiency and overall efficiency are simulated and analyzed to evaluate the dynamic performance of the hybrid photovoltaic–thermal collector. It is found that the position of phase change material layer in the photovoltaic–thermal collector has a significant effect on the performance of the photovoltaic–thermal collector. The results indicate that upper phase change material mode in the photovoltaic–thermal collector can significantly improve the thermal and electrical performance of photovoltaic–thermal collector. It is found that overall efficiency of photovoltaic–thermal collector in ‘upper phase change material’ mode is 10.7% higher than that in ‘no phase change material’ mode. Further, for a photovoltaic–thermal collector with upper phase change material, it is verified that 3 cm

  13. Dye-sensitized solar cells: Atomic scale investigation of interface structure and dynamics

    International Nuclear Information System (INIS)

    Ma Wei; Zhang Fan; Meng Sheng

    2014-01-01

    Recent progress in dye-sensitized solar cells (DSC) research is reviewed, focusing on atomic-scale investigations of the interface electronic structures and dynamical processes, including the structure of dye adsorption onto TiO 2 , ultrafast electron injection, hot-electron injection, multiple-exciton generation, and electron—hole recombination. Advanced experimental techniques and theoretical approaches are briefly summarized, and then progressive achievements in photovoltaic device optimization based on insights from atomic scale investigations are introduced. Finally, some challenges and opportunities for further improvement of dye solar cells are presented. (invited review — international conference on nanoscience and technology, china 2013)

  14. THE KEY ROLE OF SOLAR DYNAMICS IN THE CHROMOSPHERIC HANLE POLARIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, E. S.; Bianda, M., E-mail: escarlin@irsol.ch [Istituto Ricerche Solari Locarno, 6600 Locarno (Switzerland)

    2016-11-01

    The quantum theory of polarized light allows one to model scattering in the solar atmosphere for inferring its properties. This powerful approach has revealed two key long-standing problems in solar physics: the puzzling dilemmas between theory and observations in several anomalously polarized spectral lines and the need for inferring the ubiquitous weak chromospheric magnetic fields, which requires discriminating the Hanle effect in dynamic optically thick plasmas. However, the ever-present dynamics, i.e., the temporal evolution of heatings and macroscopic motions, has been widely disregarded when modeling and interpreting the scattering polarization. This has hindered a consistent theoretical solution to the puzzle while falsifying the Hanle diagnosis. Here, we show that the dynamical evolution is a keystone for solving both problems because its systematic impact allows an explanation of the observations from “anomalous” instantaneous polarization signals. Evolution accounted for, we reproduce amplitudes and (spectral and spatial) shapes of the Ca i 4227 Å polarization at solar disk center, identifying a restrictive arrangement of magnetic fields, kinematics, heatings, and spatio-temporal resolution. We find that the joint action of dynamics, Hanle effect, and low temporal resolutions mimics Zeeman linear polarization profiles, the true weak-field Zeeman signals being negligible. Our results allow reinterpretation of many polarization signals of the solar spectra and support time-dependent scattering polarization as a powerful tool for deciphering the spatio-temporal distribution of chromospheric heatings and fields. This approach may be a key aid in developing the Hanle diagnosis for the solar atmosphere.

  15. Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur-313001 (India)

    2017-05-01

    The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections at the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.

  16. Lower thermosphere (80-100 km) dynamics response to solar and geomagnetic activity: Overview

    International Nuclear Information System (INIS)

    Kazimirovsky, E.S.

    1989-01-01

    The variations of solar and geomagnetic activity may affect the thermosphere circulation via plasma heating and electric fields, especially at high latitudes. The possibility exists that the energy involved in auroral and magnetic storms can produce significant changes of mesosphere and lower thermosphere wind systems. A study of global radar measurements of winds at 80 to 100 km region revealed the short term effects (correlation between wind field and geomagnetic storms) and long term variations over a solar cycle. It seems likely that the correlation results from a modification of planetary waves and tides propagated from below, thus altering the dynamical regime of the thermosphere. Sometimes the long term behavior points rather to a climatic variation with the internal atmospheric cause than to a direct solar control

  17. Destruction of Sun-Grazing Comet C-2011 N3 (SOHO) Within the Low Solar Corona

    Science.gov (United States)

    Schrijver, C. J.; Brown, J. C.; Battams, K.; Saint-Hilaire, P.; Liu, W.; Hudson, H.; Pesnell, W. D.

    2012-01-01

    Observations of comets in Sun-grazing orbits that survive solar insolation long enough to penetrate into the Suns inner corona provide information on the solar atmosphere and magnetic field as well as on the makeup of the comet. On 6 July 2011, the Solar Dynamics Observatory (SDO) observed the demise of comet C2011 N3 (SOHO) within the low solar corona in five wavelength bands in the extreme ultraviolet (EUV). The comet penetrated to within 0.146 solarradius (100,000 kilometers) of the solar surface before its EUV signal disappeared.

  18. Statistical survey of type III radio bursts at long wavelengths observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves instruments: radio flux density variations with frequency

    Czech Academy of Sciences Publication Activity Database

    Krupař, Vratislav; Maksimovic, M.; Santolík, Ondřej; Kontar, E. P.; Cecconi, B.; Hoang, S.; Krupařová, Oksana; Souček, Jan; Reid, H.; Zaslavsky, A.

    2014-01-01

    Roč. 289, č. 8 (2014), s. 3121-3135 ISSN 0038-0938 R&D Projects: GA ČR(CZ) GAP209/12/2394; GA ČR GP13-37174P; GA ČR GAP205/10/2279 Institutional support: RVO:68378289 Keywords : solar radio emissions * plasma radiation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.039, year: 2014 http://link.springer.com/article/10.1007%2Fs11207-014-0522-x

  19. Statistical survey of type III radio bursts at long wavelengths observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves instruments: goniopolarimetric properties and radio source locations

    Czech Academy of Sciences Publication Activity Database

    Krupař, Vratislav; Maksimovic, M.; Santolík, Ondřej; Cecconi, B.; Krupařová, Oksana

    2014-01-01

    Roč. 289, č. 12 (2014), s. 4633-4652 ISSN 0038-0938 R&D Projects: GA ČR GP13-37174P; GA ČR GAP205/10/2279; GA ČR(CZ) GAP209/12/2394 Institutional support: RVO:68378289 Keywords : plasma radiation * solar radio emissions Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.039, year: 2014 http://link.springer.com/article/10.1007%2Fs11207-014-0601-z

  20. NONLINEAR DYNAMICS OF MAGNETOHYDRODYNAMIC ROSSBY WAVES AND THE CYCLIC NATURE OF SOLAR MAGNETIC ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Raphaldini, Breno; Raupp, Carlos F. M., E-mail: brenorfs@gmail.com, E-mail: carlos.raupp@iag.usp.br [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Departamento de Geofísica, Rua do Matão, 1226-Cidade Universitária São Paulo-SP 05508-090 (Brazil)

    2015-01-20

    The solar dynamo is known to be associated with several periodicities, with the nearly 11/22 yr cycle being the most pronounced one. Even though these quasiperiodic variations of solar activity have been attributed to the underlying dynamo action in the Sun's interior, a fundamental theoretical description of these cycles is still elusive. Here, we present a new possible direction in understanding the Sun's cycles based on resonant nonlinear interactions among magnetohydrodynamic (MHD) Rossby waves. The WKB theory for dispersive waves is applied to magnetohydrodynamic shallow-water equations describing the dynamics of the solar tachocline, and the reduced dynamics of a resonant triad composed of MHD Rossby waves embedded in constant toroidal magnetic field is analyzed. In the conservative case, the wave amplitudes evolve periodically in time, with periods on the order of the dominant solar activity timescale (∼11 yr). In addition, the presence of linear forcings representative of either convection or instabilities of meridionally varying background states appears to be crucial in balancing dissipation and thus sustaining the periodic oscillations of wave amplitudes associated with resonant triad interactions. Examination of the linear theory of MHD Rossby waves embedded in a latitudinally varying mean flow demonstrates that MHD Rossby waves propagate toward the equator in a waveguide from –35° to 35° in latitude, showing a remarkable resemblance to the structure of the butterfly diagram of the solar activity. Therefore, we argue that resonant nonlinear magnetohydrodynamic Rossby wave interactions might significantly contribute to the observed cycles of magnetic solar activity.

  1. A dynamic model of an innovative high-temperature solar heating and cooling system

    Directory of Open Access Journals (Sweden)

    Buonomano Annamaria

    2016-01-01

    Full Text Available In this paper a new simulation model of a novel solar heating and cooling system based on innovative high temperature flat plate evacuated solar thermal collector is presented. The system configuration includes: flat-plate evacuated solar collectors, a double-stage LiBr-H2O absorption chiller, gas-fired auxiliary heater, a closed loop cooling tower, pumps, heat exchangers, storage tanks, valves, mixers and controllers. The novelty of this study lies in the utilization of flat-plate stationary solar collectors, manufactured by TVP Solar, rather than concentrating ones (typically adopted for driving double-stage absorption chillers. Such devices show ultra-high thermal efficiencies, even at very high (about 200°C operating temperatures, thanks to the high vacuum insulation. Aim of the paper is to analyse the energy and economic feasibility of such novel technology, by including it in a prototypal solar heating and cooling system. For this purpose, the solar heating and cooling system design and performance were analysed by means of a purposely developed dynamic simulation model, implemented in TRNSYS. A suitable case study is also presented. Here, the simulated plant is conceived for the space heating and cooling and the domestic hot water production of a small building, whose energy needs are fulfilled through a real installation (settled also for experimental purposes built up close to Naples (South Italy. Simulation results show that the investigated system is able to reach high thermal efficiencies and very good energy performance. Finally, the economic analysis shows results comparable to those achieved through similar renewable energy systems.

  2. The dynamic relation between activities in the Northern and Southern solar hemispheres

    Science.gov (United States)

    Volobuev, D. M.; Makarenko, N. G.

    2016-12-01

    The north-south (N/S) asymmetry of solar activity is the most pronounced phenomenon during 11-year cycle minimums. The goal of this work is to try to interpret the asymmetry as a result of the generalized synchronization of two dynamic systems. It is assumed that these systems are localized in two solar hemispheres. The evolution of these systems is considered in the topological embeddings of a sunspot area time series obtained with the use of the Takens algorithm. We determine the coupling measure and estimate it on the time series of daily sunspot areas. The measurement made it possible to interpret the asymmetry as an exchangeable dynamic equation, in which the roles of the driver-slave components change in time for two hemispheres.

  3. Dynamic tuning of optical absorbers for accelerated solar-thermal energy storage.

    Science.gov (United States)

    Wang, Zhongyong; Tong, Zhen; Ye, Qinxian; Hu, Hang; Nie, Xiao; Yan, Chen; Shang, Wen; Song, Chengyi; Wu, Jianbo; Wang, Jun; Bao, Hua; Tao, Peng; Deng, Tao

    2017-11-14

    Currently, solar-thermal energy storage within phase-change materials relies on adding high thermal-conductivity fillers to improve the thermal-diffusion-based charging rate, which often leads to limited enhancement of charging speed and sacrificed energy storage capacity. Here we report the exploration of a magnetically enhanced photon-transport-based charging approach, which enables the dynamic tuning of the distribution of optical absorbers dispersed within phase-change materials, to simultaneously achieve fast charging rates, large phase-change enthalpy, and high solar-thermal energy conversion efficiency. Compared with conventional thermal charging, the optical charging strategy improves the charging rate by more than 270% and triples the amount of overall stored thermal energy. This superior performance results from the distinct step-by-step photon-transport charging mechanism and the increased latent heat storage through magnetic manipulation of the dynamic distribution of optical absorbers.

  4. Charge Generation Dynamics in Efficient All-Polymer Solar Cells: Influence of Polymer Packing and Morphology.

    Science.gov (United States)

    Gautam, Bhoj R; Lee, Changyeon; Younts, Robert; Lee, Wonho; Danilov, Evgeny; Kim, Bumjoon J; Gundogdu, Kenan

    2015-12-23

    All-polymer solar cells exhibit rapid progress in power conversion efficiency (PCE) from 2 to 7.7% over the past few years. While this improvement is primarily attributed to efficient charge transport and balanced mobility between the carriers, not much is known about the charge generation dynamics in these systems. Here we measured exciton relaxation and charge separation dynamics using ultrafast spectroscopy in polymer/polymer blends with different molecular packing and morphology. These measurements indicate that preferential face-on configuration with intermixed nanomorphology increases the charge generation efficiency. In fact, there is a direct quantitative correlation between the free charge population in the ultrafast time scales and the external quantum efficiency, suggesting not only the transport but also charge generation is key for the design of high performance all polymer solar cells.

  5. Early German plans for southern observatories

    Science.gov (United States)

    Wolfschmidt, G.

    2002-07-01

    As early as the 18th and 19th centuries, French and English observers were active in South Africa. Around the beginning of the 20th century, Heidelberg and Potsdam astronomers proposed a southern observatory. Then Göttingen astronomers suggested building an observatory in Windhoek for photographing the sky and measuring the solar constant. In 1910 Karl Schwarzschild (1873-1916), after a visit to observatories in the United States, pointed out the usefulness of an observatory in South West Africa, in a climate superior to that in Germany, giving German astronomers access to the southern sky. Seeing tests were begun in 1910 by Potsdam astronomers, but WW I stopped the plans. In 1928 Erwin Finlay-Freundlich (1885-1964), inspired by the Hamburg astronomer Walter Baade (1893-1960), worked out a detailed plan for a southern observatory with a reflecting telescope, spectrographs and an astrograph with an objective prism. Paul Guthnick (1879-1947), director of the Berlin observatory, in cooperation with APO Potsdam and Hamburg, made a site survey to Africa in 1929 and found the conditions in Windhoek to be ideal. Observations were started in the 1930s by Berlin and Breslau astronomers, but were stopped by WW II. In the 1950s, astronomers from Hamburg and The Netherlands renewed the discussion in the framework of European cooperation, and this led to the founding of ESO in 1963.

  6. Dynamic performance of a novel solar photovoltaic/loop-heat-pipe heat pump system

    International Nuclear Information System (INIS)

    Zhang, Xingxing; Zhao, Xudong; Shen, Jingchun; Xu, Jihuan; Yu, Xiaotong

    2014-01-01

    Highlights: • A transient model was developed to predict dynamic performance of new PV/LHP system. • The model accuracy was validated by experiment giving less than 9% in error. • The new system had basic and advanced performance coefficients of 5.51 and 8.71. • The new system had a COP 1.5–4 times that for conventional heat pump systems. • The new system had higher exergetic efficiency than PV and solar collector systems. - Abstract: Objective of the paper is to present an investigation into the dynamic performance of a novel solar photovoltaic/loop-heat-pipe (PV/LHP) heat pump system for potential use in space heating or hot water generation. The methods used include theoretical computer simulation, experimental verification, analysis and comparison. The fundamental equations governing the transient processes of solar transmission, heat transfer, fluid flow and photovoltaic (PV) power generation were appropriately integrated to address the energy balances occurring in different parts of the system, e.g., glazing cover, PV cells, fin sheet, loop heat pipe, heat pump cycle and water tank. A dedicated computer model was developed to resolve the above grouping equations and consequently predict the system’s dynamic performance. An experimental rig was constructed and operated under the real weather conditions for over one week in Shanghai to evaluate the system living performance, which was undertaken by measurement of various operational parameters, e.g., solar radiation, photovoltaic power generation, temperatures and heat pump compressor consumption. On the basis of the first- (energetic) and second- (exergetic) thermodynamic laws, an overall evaluation approach was proposed and applied to conduct both quantitative and qualitative analysis of the PV/LHP module’s efficiency, which involved use of the basic thermal performance coefficient (COP th ) and the advanced performance coefficient (COP PV/T ) of such a system. Moreover, a simple comparison

  7. Dynamical Networks Characterization of Geomagnetic Substorms and Transient Response to the Solar Wind State.

    Science.gov (United States)

    Chapman, S. C.; Dods, J.; Gjerloev, J. W.

    2017-12-01

    Observations of how the solar wind interacts with earth's magnetosphere, and its dynamical response, are increasingly becoming a data analytics challenge. Constellations of satellites observe the solar corona, the upstream solar wind and throughout earth's magnetosphere. These data are multipoint in space and extended in time, so in principle are ideal for study using dynamical networks to characterize the full time evolving spatial pattern. We focus here on analysis of data from the full set of 100+ auroral ground based magnetometer stations that have been collated by SuperMAG. Spatio-temporal patterns of correlation between the magnetometer time series can be used to form a dynamical network [1]. The properties of the network can then be captured by (time dependent) network parameters. This offers the possibility of characterizing detailed spatio-temporal pattern by a few parameters, so that many events can then be compared [2] with each other. Whilst networks are in widespread use in the data analytics of societal and commercial data, there are additional challenges in their application to physical timeseries. Determining whether two nodes (here, ground based magnetometer stations) are connected in a network (seeing the same dynamics) requires normalization w.r.t. the detailed sensitivities and dynamical responses of specific observing stations and seasonal conductivity variations and we have developed methods to achieve this dynamical normalization. The detailed properties of the network capture time dependent spatial correlation in the magnetometer responses and we will show how this can be used to infer a transient current system response to magnetospheric activity. [l] Dods et al, J. Geophys. Res 120, doi:10.1002/2015JA02 (2015). [2] Dods et al, J. Geophys. Res. 122, doi:10.1002/2016JA02 (2017).

  8. On the track of gravity modes: study of the dynamics of the solar core

    International Nuclear Information System (INIS)

    Mathur, Savita

    2007-01-01

    This thesis is dedicated to the study of the dynamics of the solar radiative zone through gravity modes. Though the core represents more than 50% of the solar mass, we still do not have an accurate vision of the rotation profile in the very inner part of the Sun. To understand the evolution of stars, we try to put constraints on dynamic processes. Several paths have been followed in this thesis to tackle this issue: solar modeling, the study of a new instrument, observations and inversions of the rotation. The necessity of the detection of gravity modes is driven by the will for a better comprehension of the solar dynamics. With a technological prototype built at the CEA (GOLF-NG), we want to validate a few technical points and prepare the scientific mission which aim will be to detect these gravity modes. We studied first the photodetector and then the whole instrument response. We show the feasibility of the instrument. The observation of the resonance in all the channels proves that it works the way we expected. However, before this mission takes place, the analysis of GOLF data enabled us to detect one gravity-mode candidate as well as the signature of dipole gravity modes. This work benefited from a more theoretical approach on the prediction of gravity-mode frequencies. We show the influence of several physical processes and quantities. Finally, as the dynamical processes in the Sun are not well constrained, we tried to understand the impact of the introduction of one and several gravity modes on the inferred rotation profiles. We also tried to give constraints on the observations so that we could obtain some information on the rotation profile in the core. (author) [fr

  9. Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.

    1986-01-01

    Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

  10. Charge Carrier Dynamics of Methylammonium Lead-Iodide Perovskite Solar Cells

    OpenAIRE

    Neukom, Martin Thomas

    2016-01-01

    Transient opto-electrical measurements of methylammonium lead iodide (MALI) perovskite solar cells (PSCs) are performed and analyzed in order to elucidate the operating mechanisms. The current response to a light pulse or voltage pulse shows an extraordinarily broad dynamic range covering 9 orders of magnitude in time - from microseconds to minutes - until steady-state is reached. Evidence of a slowly changing charge density at the perovskite layer boundaries is found, which is most probably ...

  11. An IRIS Optically Thin View of the Dynamics of the Solar Chromosphere

    Science.gov (United States)

    Carlsson, M.

    2017-12-01

    We analyze the formation of the O I 1356 and Cl I 1351 lines and show that they are formed in the mid-chromosphere and are optically thin. Their non-thermal line-widths are thus a direct measure of the velocity field along the line of sight. We use this insight to analyze a large set of observations from the Interface Region Imaging Spectrograph (IRIS) to study the dynamics of the Solar Chromosphere.

  12. SPASE and the Heliophysics Virtual Observatories

    Directory of Open Access Journals (Sweden)

    J R Thieman

    2010-02-01

    Full Text Available The Space Physics Archive Search and Extract (SPASE project has developed an information model for interoperable access and retrieval of data within the Heliophysics (also known as space and solar physics science community. The diversity of science data archives within this community has led to the establishment of many virtual observatories to coordinate the data pathways within Heliophysics subdisciplines, such as magnetospheres, waves, radiation belts, etc. The SPASE information model provides a semantic layer and common language for data descriptions so that searches might be made across the whole of the heliophysics data environment, especially through the virtual observatories.

  13. The Sudbury neutrino observatory

    International Nuclear Information System (INIS)

    McLatchie, W.; Earle, E.D.

    1987-08-01

    This report initially discusses the Homestake Mine Experiment, South Dakota, U.S.A. which has been detecting neutrinos in 38 x 10 litre vats of cleaning fluid containing chlorine since the 1960's. The interation between neutrinos and chlorine produces argon so the number of neutrinos over time can be calculated. However, the number of neutrinos which have been detected represent only one third to one quarter of the expected number i.e. 11 per month rather than 48. It is postulated that the electron-neutrinos originating in the solar core could change into muon- or tau-neutrinos during passage through the high electron densities of the sun. The 'low' results at Homestake could thus be explained by the fact that the experiment is only sensitive to electron-neutrinos. The construction of a heavy water detector is therefore proposed as it would be able to determine the energy of the neutrinos, their time of arrival at the detector and their direction. It is proposed to build the detector at Creighton mine near Sudbury at a depth of 6800 feet below ground level thus shielding the detector from cosmic rays which would completely obscure the neutrino signals from the detector. The report then discusses the facility itself, the budget estimate and the social and economic impact on the surrounding area. At the time of publication the proposal for the Sudbury Neutrino Observatory was due to be submitted for peer review by Oct. 1, 1987 and then to various granting bodies charged with the funding of scientific research in Canada, the U.S.A. and Britain

  14. Effects of Abrupt Variations of Solar Wind Dynamic Pressure on the High-Latitude Ionosphere

    Directory of Open Access Journals (Sweden)

    Igino Coco

    2011-01-01

    Full Text Available We show the results of a statistical study on the effects in the high-latitude ionosphere of abrupt variations of solar wind dynamic pressure, using Super Dual Auroral Radar Network (SuperDARN data in both hemispheres. We find that, during periods of quiet ionospheric conditions, the amount of radar backscatter increases when a variation in the dynamic pressure occurs, both positive (increase of the pressure and negative (decrease of the pressure. We also investigate the behaviour of the Cross-Polar Cap Potential (CPCP during pressure variations and show preliminary results.

  15. Global-scale equatorial Rossby waves as an essential component of solar internal dynamics

    Science.gov (United States)

    Löptien, Björn; Gizon, Laurent; Birch, Aaron C.; Schou, Jesper; Proxauf, Bastian; Duvall, Thomas L.; Bogart, Richard S.; Christensen, Ulrich R.

    2018-05-01

    The Sun’s complex dynamics is controlled by buoyancy and rotation in the convection zone. Large-scale flows are dominated by vortical motions1 and appear to be weaker than expected in the solar interior2. One possibility is that waves of vorticity due to the Coriolis force, known as Rossby waves3 or r modes4, remove energy from convection at the largest scales5. However, the presence of these waves in the Sun is still debated. Here, we unambiguously discover and characterize retrograde-propagating vorticity waves in the shallow subsurface layers of the Sun at azimuthal wavenumbers below 15, with the dispersion relation of textbook sectoral Rossby waves. The waves have lifetimes of several months, well-defined mode frequencies below twice the solar rotational frequency, and eigenfunctions of vorticity that peak at the equator. Rossby waves have nearly as much vorticity as the convection at the same scales, thus they are an essential component of solar dynamics. We observe a transition from turbulence-like to wave-like dynamics around the Rhines scale6 of angular wavenumber of approximately 20. This transition might provide an explanation for the puzzling deficit of kinetic energy at the largest spatial scales.

  16. Dynamic solar-powered multi-stage direct contact membrane distillation system: Concept design, modeling and simulation

    KAUST Repository

    Lee, Jung Gil; Kim, Woo-Seung; Choi, June-Seok; Ghaffour, NorEddine; Kim, Young-Deuk

    2017-01-01

    This paper presents a theoretical analysis of the monthly average daily and hourly performances of a solar-powered multi-stage direct contact membrane distillation (SMDCMD) system with an energy recovery scheme and dynamic operating system. Mid

  17. A DP based scheme for real-time reconfiguration of solar cell arrays exposed to dynamic changing inhomogeneous illuminations

    DEFF Research Database (Denmark)

    Shi, Liping; Brehm, Robert

    2016-01-01

    The overall energy conversion efficiency of solar cell arrays is highly effected by partial shading effects. Especially for solar panel arrays installed in environments which are exposed to inhomogeneous dynamic changing illuminations such as on roof tops of electrical vehicles the overall system...... efficiency is drastically reduced. Dynamic real-time reconfiguration of the solar panel array can reduce effects on the output efficiency due to partial shading. This results in a maximized power output of the panel array when exposed to dynamic changing illuminations. The optimal array configuration...... with respect to shading patterns can be stated as a combinatorial optimization problem and this paper proposes a dynamic programming (DP) based algorithm which finds the optimal feasible solution to reconfigure the solar panel array for maximum efficiency in real-time with linear time complexity. It is shown...

  18. A novel small dynamic solar thermal desalination plant with a fluid piston converter

    International Nuclear Information System (INIS)

    Mahkamov, Khamid; Orda, Eugene; Belgasim, Basim; Makhkamova, Irina

    2015-01-01

    Highlights: • A dynamic solar desalination plant was developed which works cyclically. • It integrates an evacuated tube solar collector and fluid piston converter. • Pressure during desalination process varies with frequency of 2–4 Hz. • The system has a small increase in fresh water yield and provides pumping capacity. • Mathematical modelling provides accurate description of experimental performance. - Abstract: An innovative small dynamic water desalination plant was developed and tested under laboratory conditions. The system is a combination of a heat pipe evacuated tube solar collector, conventional condenser and novel fluid piston converter. Saline water is boiled and turned into vapour in the manifold of the solar collector. A small fraction of the solar energy supplied to the plant is used to drive the fluid piston converter. Oscillations of the fluid piston periodically change the volume and pressure in the plant. For the duration of approximately half of the periodic cycle the pressure in the plant drops below the atmospheric level causing flash boiling of saline water in the manifold of the solar collector. Generated vapour is turned into fresh water in the condenser which is surrounded by a cooling jacket with saline water. The flash boiling effect improves the fresh water production capacity of the plant. Additionally, the fluid piston converter drives a pump which provides lifting of saline water from a well and pumps this through the cooling jacket of the condenser to a saline water storage tank. This tank replenishes saline water in the manifold of the solar collector. Experimental investigations demonstrated the saline water self-circulation capability of the plant and increase in the fresh water production compared to the static mode of operation. Experimental data was also used to calibrate the mathematical model of the plant. Comparison of theoretical and experimental information demonstrates that the model accurately predicts the

  19. Early German Plans for a Southern Observatory

    Science.gov (United States)

    Wolfschmidt, Gudrun

    As early as the 18th and 19th centuries, French and English observers were active in South Africa. Around the beginning of the 20th century the Heidelberg astronomer Max Wolf (1863-1932) proposed a southern observatory. In 1907 Hermann Carl Vogel (1841-1907), director of the Astrophysical Observatory Potsdam, suggested a southern station in Spain. His ideas for building an observatory in Windhuk for photographing the sky and measuring the solar constant were taken over by the Göttingen astronomers. In 1910 Karl Schwarzschild (1873-1916), after having visited the observatories in America, pointed out the usefulness of an observatory in South West Africa, where it would have better weather than in Germany and also give access to the southern sky. Seeing tests were begun in 1910 by Potsdam astronomers, but WW I stopped the plans. In 1928 Erwin Finlay-Freundlich (1885-1964), inspired by the Hamburg astronomer Walter Baade (1893-1960), worked out a detailed plan for a southern observatory with a reflecting telescope, spectrographs and an astrograph with an objective prism. Paul Guthnick (1879-1947), director of the Berlin observatory, in cooperation with APO Potsdam and Hamburg, made a site survey to Africa in 1929 and found the conditions in Windhuk to be ideal. Observations were started in the 1930s by Berlin and Breslau astronomers, but were stopped by WW II. In the 1950s, astronomers from Hamburg and The Netherlands renewed the discussion in the framework of European cooperation, and this led to the founding of ESO in 1963, as is well described by Blaauw (1991). Blaauw, Adriaan: ESO's Early History. The European Southern Observatory from Concept to Reality. Garching bei München: ESO 1991.

  20. A Green Robotic Observatory for Astronomy Education

    Science.gov (United States)

    Reddy, Vishnu; Archer, K.

    2008-09-01

    With the development of robotic telescopes and stable remote observing software, it is currently possible for a small institution to have an affordable astronomical facility for astronomy education. However, a faculty member has to deal with the light pollution (observatory location on campus), its nightly operations and regular maintenance apart from his day time teaching and research responsibilities. While building an observatory at a remote location is a solution, the cost of constructing and operating such a facility, not to mention the environmental impact, are beyond the reach of most institutions. In an effort to resolve these issues we have developed a robotic remote observatory that can be operated via the internet from anywhere in the world, has a zero operating carbon footprint and minimum impact on the local environment. The prototype observatory is a clam-shell design that houses an 8-inch telescope with a SBIG ST-10 CCD detector. The brain of the observatory is a low draw 12-volt harsh duty computer that runs the dome, telescope, CCD camera, focuser, and weather monitoring. All equipment runs of a 12-volt AGM-style battery that has low lead content and hence more environmental-friendly to dispose. The total power of 12-14 amp/hrs is generated from a set of solar panels that are large enough to maintain a full battery charge for several cloudy days. This completely eliminates the need for a local power grid for operations. Internet access is accomplished via a high-speed cell phone broadband connection or satellite link eliminating the need for a phone network. An independent observatory monitoring system interfaces with the observatory computer during operation. The observatory converts to a trailer for transportation to the site and is converted to a semi-permanent building without wheels and towing equipment. This ensures minimal disturbance to local environment.

  1. Application of dynamic model to predict some inside environment variables in a semi-solar greenhouse

    Directory of Open Access Journals (Sweden)

    Behzad Mohammadi

    2018-06-01

    Full Text Available Greenhouses are one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very high. The greenhouse environment is an uncertain nonlinear system which classical modeling methods have some problems to solve it. There are many control methods, such as adaptive, feedback and intelligent control and they require a precise model. Therefore, many modeling methods have been proposed for this purpose; including physical, transfer function and black-box modeling. The objective of this paper is to modeling and experimental validation of some inside environment variables in an innovative greenhouse structure (semi-solar greenhouse. For this propose, a semi-solar greenhouse was designed and constructed at the North-West of Iran in Azerbaijan Province (38°10′N and 46°18′E with elevation of 1364 m above the sea level. The main inside environment factors include inside air temperature (Ta and inside soil temperature (Ts were collected as the experimental data samples. The dynamic heat transfer model used to estimate the temperature in two different points of semi-solar greenhouse with initial values. The results showed that dynamic model can predict the inside temperatures in two different points (Ta and Ts with RMSE, MAPE and EF about 5.3 °C, 10.2% and 0.78% and 3.45 °C, 7.7% and 0.86%, respectively. Keywords: Semi-solar greenhouse, Dynamic model, Commercial greenhouse

  2. The Atsa Suborbital Observatory: An Observatory for a Commercial Suborbital Spacecraft

    Science.gov (United States)

    Vilas, F.; Sollitt, L. S.

    2012-12-01

    The advantages of astronomical observations made above Earth's atmosphere have long been understood: free access to spectral regions inaccessible from Earth (e.g., UV) or affected by the atmosphere's content (e.g., IR). Most robotic, space-based telescopes maintain large angular separation between the Sun and an observational target in order to avoid accidental damage to instruments from the Sun. For most astronomical targets, this possibility is easily avoided by waiting until objects are visible away from the Sun. For the Solar System objects inside Earth's orbit, this is never the case. Suborbital astronomical observations have over 50 years' history using NASA's sounding rockets and experimental space planes. Commercial suborbital spacecraft are largely expected to go to ~100 km altitude above Earth, providing a limited amount of time for astronomical observations. The unique scientific advantage to these observations is the ability to point close to the Sun: if a suborbital spacecraft accidentally turns too close to the Sun and fries an instrument, it is easy to land the spacecraft and repair the hardware for the next flight. Objects uniquely observed during the short observing window include inner-Earth asteroids, Mercury, Venus, and Sun-grazing comets. Both open-FOV and target-specific observations are possible. Despite many space probes to the inner Solar System, scientific questions remain. These include inner-Earth asteroid size and bulk density informing Solar System evolution studies and efforts to develop methods of mitigation against imminent impactors to Earth; chemistry and dynamics of Venus' atmosphere addressing physical phenomena such as greenhouse effect, atmospheric super-rotation and global resurfacing on Venus. With the Atsa Suborbital Observatory, we combine the strengths of both ground-based observatories and space-based observing to create a facility where a telescope is maintained and used interchangeably with both in-house facility

  3. Solar energetic particles and radio burst emission

    Directory of Open Access Journals (Sweden)

    Miteva Rositsa

    2017-01-01

    Full Text Available We present a statistical study on the observed solar radio burst emission associated with the origin of in situ detected solar energetic particles. Several proton event catalogs in the period 1996–2016 are used. At the time of appearance of the particle origin (flare and coronal mass ejection we identified radio burst signatures of types II, III and IV by inspecting dynamic radio spectral plots. The information from observatory reports is also accounted for during the analysis. The occurrence of solar radio burst signatures is evaluated within selected wavelength ranges during the solar cycle 23 and the ongoing 24. Finally, we present the burst occurrence trends with respect to the intensity of the proton events and the location of their solar origin.

  4. Model validation of solar PV plant with hybrid data dynamic simulation based on fast-responding generator method

    Directory of Open Access Journals (Sweden)

    Zhao Dawei

    2016-01-01

    Full Text Available In recent years, a significant number of large-scale solar photovoltaic (PV plants have been put into operation or been under planning around the world. The model accuracy of solar PV plant is the key factor to investigate the mutual influences between solar PV plants and a power grid. However, this problem has not been well solved, especially in how to apply the real measurements to validate the models of the solar PV plants. Taking fast-responding generator method as an example, this paper presents a model validation methodology for solar PV plant via the hybrid data dynamic simulation. First, the implementation scheme of hybrid data dynamic simulation suitable for DIgSILENT PowerFactory software is proposed, and then an analysis model of solar PV plant integration based on IEEE 9 system is established. At last, model validation of solar PV plant is achieved by employing hybrid data dynamic simulation. The results illustrate the effectiveness of the proposed method in solar PV plant model validation.

  5. Long-term dynamics of OH * temperatures over central Europe: trends and solar correlations

    Directory of Open Access Journals (Sweden)

    C. Kalicinsky

    2016-12-01

    Full Text Available We present the analysis of annual average OH* temperatures in the mesopause region derived from measurements of the Ground-based Infrared P-branch Spectrometer (GRIPS at Wuppertal (51° N, 7° E in the time interval 1988 to 2015. The new study uses a temperature time series which is 7 years longer than that used for the latest analysis regarding the long-term dynamics. This additional observation time leads to a change in characterisation of the observed long-term dynamics. We perform a multiple linear regression using the solar radio flux F10.7 cm (11-year cycle of solar activity and time to describe the temperature evolution. The analysis leads to a linear trend of (−0.089 ± 0.055 K year−1 and a sensitivity to the solar activity of (4.2 ± 0.9 K (100 SFU−1 (r2 of fit 0.6. However, one linear trend in combination with the 11-year solar cycle is not sufficient to explain all observed long-term dynamics. In fact, we find a clear trend break in the temperature time series in the middle of 2008. Before this break point there is an explicit negative linear trend of (−0.24 ± 0.07 K year−1, and after 2008 the linear trend turns positive with a value of (0.64 ± 0.33 K year−1. This apparent trend break can also be described using a long periodic oscillation. One possibility is to use the 22-year solar cycle that describes the reversal of the solar magnetic field (Hale cycle. A multiple linear regression using the solar radio flux and the solar polar magnetic field as parameters leads to the regression coefficients Csolar = (5.0 ± 0.7 K (100 SFU−1 and Chale = (1.8 ±  0.5 K (100 µT−1 (r2 = 0.71. The second way of describing the OH* temperature time series is to use the solar radio flux and an oscillation. A least-square fit leads to a sensitivity to the solar activity of (4.1 ± 0.8 K (100 SFU−1, a period P  =  (24.8 ± 3.3 years, and

  6. Dynamic Modeling, Control, and Analysis of a Solar Water Pumping System for Libya

    Directory of Open Access Journals (Sweden)

    Muamer M. Shebani

    2017-01-01

    Full Text Available In recent years, one of the suitable solar photovoltaic (PV applications is a water pumping system. The simplest solar PV pumping system consists of PV array, DC-DC converter, DC motor, and water pump. In this paper, water pumping system sizing for Libya is evaluated based on a daily demand using HOMER software, and dynamic modeling of a solar PV water pumping system using a Permanent Magnet DC (PMDC motor is presented in Matlab/Simulink environment. The system performance with maximum power point tracking (MPPT based on Fractional Open Circuit Voltage (FOCV is evaluated with and without a battery storage system. In some applications, a rated voltage is needed to connect a PMDC motor to a PV array through a DC-DC converter and in other applications the input voltage can vary. The evaluation of the system is based on the performance during a change in solar irradiation. Using Matlab/Simulink, simulation results are assessed to see the efficiency of the system when it is operating at a specific speed or at the MPPT. The results show that an improvement in the system efficiency can be achieved when the PMDC motor is running at a specific speed rather than at the peak PV power point.

  7. EARLY DYNAMICAL EVOLUTION OF THE SOLAR SYSTEM: PINNING DOWN THE INITIAL CONDITIONS OF THE NICE MODEL

    International Nuclear Information System (INIS)

    Batygin, Konstantin; Brown, Michael E.

    2010-01-01

    In the recent years, the 'Nice' model of solar system formation has attained an unprecedented level of success in reproducing much of the observed orbital architecture of the solar system by evolving the planets to their current locations from a more compact configuration. Within the context of this model, the formation of the classical Kuiper Belt requires a phase during which the ice giants have a high eccentricity. An outstanding question of this model is the initial configuration from which the solar system started out. Recent work has shown that multi-resonant initial conditions can serve as good candidates, as they naturally prevent vigorous type-II migration. In this paper, we use analytical arguments, as well as self-consistent numerical N-body simulations to identify fully resonant initial conditions, whose dynamical evolution is characterized by an eccentric phase of the ice giants, as well as planetary scattering. We find a total of eight such initial conditions. Four of these primordial states are compatible with the canonical 'Nice' model, while the others imply slightly different evolutions. The results presented here should prove useful in further development of a comprehensive model for solar system formation.

  8. Dynamics of ozone layer under Serbia and solar activity: Previous statement

    Directory of Open Access Journals (Sweden)

    Ducić Vladan

    2008-01-01

    Full Text Available The aim of this paper is to identify ozone layer dynamics under Serbian area, as well as possible relations of change in stratospheric ozone concentration with some parameters of solar activity. During the period 1979-2005, the statistical decrease of ozone concentration was noticed under Serbian territory cumulatively for 24.5 DU (7.2%, apropos 9.4 DU (2.8% by decade. These changes are consistent with the changes in surrounding countries. From absolute minimum 1993, flexible trend of ozone layer pentad values validate hypotheses of its recovery. Correspondence of ozone thickness extreme period with Wolf's number and with the greatest volcanic eruptions shows that interannual variations of stratospheric ozone concentration are still in the function of natural factors above all, as are solar and volcanic activities. Investigation of larger number solar activity parameters shows statistically important antiphase synchronous between the number of polar faculae on the Sun and stratospheric ozone dynamics under Serbia. Respecting that relation between these two features until now isn't depicted, some possible causal mechanisms are proposed.

  9. Energetic, exergetic and financial evaluation of a solar driven absorption chiller – A dynamic approach

    International Nuclear Information System (INIS)

    Bellos, Evangelos; Tzivanidis, Christos; Symeou, Christoforos; Antonopoulos, Kimon A.

    2017-01-01

    Highlights: • A solar cooling system with ETC and a single effect absorption chiller is analyzed. • The analysis is dynamic and it is made for the city of Athens, Greece. • The analysis is energetic, exergetic and financial for all the summer period. • Firstly the system is optimized exergetically and after it is analyzed financially. • The optimum case is 450 m"2 of solar collectors coupled with a storage tank of 14 m"3. - Abstract: In this study, a solar cooling system of 100 kW is analyzed parametrically in dynamic basis for the city of Athens, Greece. The objective of this study is the design of a sustainable system, using energetic, exergetic and financial criteria. The examined system includes evacuated tube collectors, storage tank and a single stage absorption chiller operating with LiBr-H_2O working pair. Different combinations of collecting areas and storage tank volumes are tested in order to determine the most suitable cases exergetically. These optimum cases are evaluated financially and finally the system with the higher financial indexes is selected as the most suitable. More specifically, the collecting area is analyzed from 150 m"2 to 600 m"2 and the storage tank from 6 m"3 to 16 m"3. Finally, 450 m"2 of evacuated tube collectors with a 14 m"3 storage tank was proved to be the optimum solution financially with 15 years payback period and 67 k€ net present value.

  10. Analyses and Comparison of Solar Air Heater with Various Rib Roughness using Computational Fluid Dynamics (CFD)

    Science.gov (United States)

    Kumar, K. Ravi; Cheepu, Muralimohan; Srinivas, B.; Venkateswarlu, D.; Pramod Kumar, G.; Shiva, Apireddi

    2018-03-01

    In solar air heater, artificial roughness on absorber plate become prominent technique to improving heat transfer rate of air flowing passage as a result of laminar sublayer. The selection of rib geometries plays important role on friction characteristics and heat transfer rate. Many researchers studying the roughness shapes over the years to investigate the effect of geometries on the performance of friction factor and heat transfer of the solar air heater. The present study made an attempt to develop the different rib shapes utilised for creating artificial rib roughness and its comparison to investigate higher performance of the geometries. The use of computational fluid dynamics software resulted in correlation of friction factor and heat transfer rate. The simulations studies were performed on 2D computational fluid dynamics model and analysed to identify the most effective parameters of relative roughness of the height, width and pitch on major considerations of friction factor and heat transfer. The Reynolds number is varied in a range from 3000 to 20000, in the current study and modelling has conducted on heat transfer and turbulence phenomena by using Reynolds number. The modelling results showed the formation of strong vortex in the main stream flow due to the right angle triangle roughness over the square, rectangle, improved rectangle and equilateral triangle geometries enhanced the heat transfer extension in the solar air heater. The simulation of the turbulence kinetic energy of the geometry suggests the local turbulence kinetic energy has been influenced strongly by the alignments of the right angle triangle.

  11. Solar Activity Across the Scales: From Small-Scale Quiet-Sun Dynamics to Magnetic Activity Cycles

    Science.gov (United States)

    Kitiashvili, Irina N.; Collins, Nancy N.; Kosovichev, Alexander G.; Mansour, Nagi N.; Wray, Alan A.

    2017-01-01

    Observations as well as numerical and theoretical models show that solar dynamics is characterized by complicated interactions and energy exchanges among different temporal and spatial scales. It reveals magnetic self-organization processes from the smallest scale magnetized vortex tubes to the global activity variation known as the solar cycle. To understand these multiscale processes and their relationships, we use a two-fold approach: 1) realistic 3D radiative MHD simulations of local dynamics together with high resolution observations by IRIS, Hinode, and SDO; and 2) modeling of solar activity cycles by using simplified MHD dynamo models and mathematical data assimilation techniques. We present recent results of this approach, including the interpretation of observational results from NASA heliophysics missions and predictive capabilities. In particular, we discuss the links between small-scale dynamo processes in the convection zone and atmospheric dynamics, as well as an early prediction of Solar Cycle 25.

  12. The Influence of the Relaxation Time on the Dynamic Hysteresis in Perovskite Solar Cells

    Directory of Open Access Journals (Sweden)

    Palici Alexandra

    2018-01-01

    Full Text Available We investigate the dynamic behavior of perovskite solar cells by focusing on the relaxation time τ, which corresponds to the slow de-polarization process from an initial bias pre-poled state. The dynamic electrical model (DEM is employed for simulating the J-V characteristics for different bias scan rates and pre-poling conditions. Depending on the sign of the initial polarization normal or inverted hysteresis may be induced. For fixed pre-poling conditions, the relaxation time, in relation to the bias scan rate, governs the magnitude of the dynamic hysteresis. In the limit of large τ the hysteretic effects are vanishing for the typical range of bias scan rates considered, while for very small τ the hysteresis is significant only when it is comparable with the measurement time interval.

  13. Carrier transport dynamics in Mn-doped CdSe quantum dot sensitized solar cells

    Science.gov (United States)

    Poudyal, Uma; Maloney, Francis S.; Sapkota, Keshab; Wang, Wenyong

    2017-10-01

    In this work quantum dot sensitized solar cells (QDSSCs) were fabricated with CdSe and Mn-doped CdSe quantum dots (QDs) using the SILAR method. QDSSCs based on Mn-doped CdSe QDs exhibited improved incident photon-to-electron conversion efficiency. Carrier transport dynamics in the QDSSCs were studied using the intensity modulated photocurrent/photovoltage spectroscopy technique, from which transport and recombination time constants could be derived. Compared to CdSe QDSSCs, Mn-CdSe QDSSCs exhibited shorter transport time constant, longer recombination time constant, longer diffusion length, and higher charge collection efficiency. These observations suggested that Mn doping in CdSe QDs could benefit the performance of solar cells based on such nanostructures.

  14. Stochastic Modelling, Analysis, and Simulations of the Solar Cycle Dynamic Process

    Science.gov (United States)

    Turner, Douglas C.; Ladde, Gangaram S.

    2018-03-01

    Analytical solutions, discretization schemes and simulation results are presented for the time delay deterministic differential equation model of the solar dynamo presented by Wilmot-Smith et al. In addition, this model is extended under stochastic Gaussian white noise parametric fluctuations. The introduction of stochastic fluctuations incorporates variables affecting the dynamo process in the solar interior, estimation error of parameters, and uncertainty of the α-effect mechanism. Simulation results are presented and analyzed to exhibit the effects of stochastic parametric volatility-dependent perturbations. The results generalize and extend the work of Hazra et al. In fact, some of these results exhibit the oscillatory dynamic behavior generated by the stochastic parametric additative perturbations in the absence of time delay. In addition, the simulation results of the modified stochastic models influence the change in behavior of the very recently developed stochastic model of Hazra et al.

  15. TENCompetence Competence Observatory

    NARCIS (Netherlands)

    Vervenne, Luk

    2010-01-01

    Vervenne, L. (2007) TENCompetence Competence Observatory. Sources available http://tencompetence.cvs.sourceforge.net/viewvc/tencompetence/wp8/org.tencompetence.co/. Available under the three clause BSD license, copyright TENCompetence Foundation.

  16. Long Baseline Observatory (LBO)

    Data.gov (United States)

    Federal Laboratory Consortium — The Long Baseline Observatory (LBO) comprises ten radio telescopes spanning 5,351 miles. It's the world's largest, sharpest, dedicated telescope array. With an eye...

  17. The Pierre Auger Observatory

    International Nuclear Information System (INIS)

    Hojvat, C.

    1997-03-01

    The Pierre Auger Observatory is an international collaboration for the detailed study of the highest energy cosmic rays. It will operate at two similar sites, one in the northern hemisphere and one in the southern hemisphere. The Observatory is designed to collect a statistically significant data set of events with energies greater than 10 19 eV and with equal exposures for the northern and southern skies

  18. Study on the System Design of a Solar Assisted Ground Heat Pump System Using Dynamic Simulation

    Directory of Open Access Journals (Sweden)

    Min Gyung Yu

    2016-04-01

    Full Text Available Recently, the use of hybrid systems using multiple heat sources in buildings to ensure a stable energy supply and improve the system performance has gained attention. Among them, a heat pump system using both solar and ground heat was developed and various system configurations have been introduced. However, establishing a suitable design method for the solar-assisted ground heat pump (SAGHP system including a thermal storage tank is complicated and there are few quantitative studies on the detailed system configurations. Therefore, this study developed three SAGHP system design methods considering the design factors focused on the thermal storage tank. Using dynamic energy simulation code (TRNSYS 17, individual performance analysis models were developed and long-term quantitative analysis was carried out to suggest optimum design and operation methods. As a result, it was found that SYSTEM 2 which is a hybrid system with heat storage tank for only a solar system showed the highest average heat source temperature of 14.81 °C, which is about 11 °C higher than minimum temperature in SYSTEM 3. Furthermore, the best coefficient of performance (COP values of heat pump and system were 5.23 and 4.32 in SYSYEM 2, using high and stable solar heat from a thermal storage tank. Moreover, this paper considered five different geographical and climatic locations and the SAGHP system worked efficiently in having high solar radiation and cool climate zones and the system COP was 4.51 in the case of Winnipeg (Canada where the highest heating demand is required.

  19. Autonomous Infrastructure for Observatory Operations

    Science.gov (United States)

    Seaman, R.

    This is an era of rapid change from ancient human-mediated modes of astronomical practice to a vision of ever larger time domain surveys, ever bigger "big data", to increasing numbers of robotic telescopes and astronomical automation on every mountaintop. Over the past decades, facets of a new autonomous astronomical toolkit have been prototyped and deployed in support of numerous space missions. Remote and queue observing modes have gained significant market share on the ground. Archives and data-mining are becoming ubiquitous; astroinformatic techniques and virtual observatory standards and protocols are areas of active development. Astronomers and engineers, planetary and solar scientists, and researchers from communities as diverse as particle physics and exobiology are collaborating on a vast range of "multi-messenger" science. What then is missing?

  20. Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2005-06-01

    Full Text Available The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999 allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time at a radial distance of 24 to 30 RE (Earth radii. During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left- and right-hand polarized electromagnetic ion cyclotron (EIC waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (= $T_{p, perp}/T_{p, parallel}{-}1$ became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the

  1. Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2005-06-01

    Full Text Available The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999 allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time at a radial distance of 24 to 30 RE (Earth radii. During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left- and right-hand polarized electromagnetic ion cyclotron (EIC waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (= became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the low latitude boundary layer (LLBL and duskside magnetosphere occurred under such inflated conditions that the magnetospheric magnetic pressure was insufficient to maintain pressure balance. In these crossings, the inner edge of

  2. Latent energy storage with salt and metal mixtures for solar dynamic applications

    Science.gov (United States)

    Crane, R. A.; Konstantinou, K. S.

    1988-01-01

    This paper examines three design alternatives for the development of a solar dynamic heat receiver as applied to power systems operating in low earth orbit. These include a base line design used for comparison in ongoing NASA studies, a system incorporating a salt energy storage system with the salt dispersed within a metal mesh and a hybrid system incorporating both a molten salt and molten metal for energy storage. Based on a typical low earth orbit condition, designs are developed and compared to determine the effect of resultant conductivity, heat capacity and heat of fusion on system size, weight, temperature gradients, cycle turbine inlet temperature and material utilization.

  3. Dynamic Modelling of a Solar Water Pumping System with Energy Storage

    OpenAIRE

    Shatadru Biswas; M. Tariq Iqbal

    2018-01-01

    This paper describes the dynamic modelling of a system used for extraction of groundwater for irrigation using an alternative source of energy. The system is designed based on data of an existing project in Lalmonirhat, Bangladesh. The system comprises a 38.4 kWp solar photovoltaic array, inverter, AC motor, and pump set, which can discharge a maximum of 1,930 m3 of water per day. MATLAB simulation is performed with two types of energy storage system: (i) electric energy using a battery bank ...

  4. Thermal energy storage for organic Rankine cycle solar dynamic space power systems

    Science.gov (United States)

    Heidenreich, G. R.; Parekh, M. B.

    An organic Rankine cycle-solar dynamic power system (ORC-SDPS) comprises a concentrator, a radiator, a power conversion unit, and a receiver with a thermal energy storage (TES) subsystem which charges and discharges energy to meet power demands during orbital insolation and eclipse periods. Attention is presently given to the criteria used in designing and evaluating an ORC-SDPS TES, as well as the automated test facility employed. It is found that a substantial data base exists for the design of an ORC-SDPS TES subsystem.

  5. The variations of oxygen emissions in corresponding to Earth's aurora in low latitude region under influence of solar wind dynamics

    Science.gov (United States)

    Jamlongkul, P.; Wannawichian, S.

    2017-12-01

    Earth's aurora in low latitude region was studied via time variations of oxygen emission spectra, simultaneously with solar wind data. The behavior of spectrum intensity, in corresponding with solar wind condition, could be a trace of aurora in low latitude region including some effects of high energetic auroral particles. Oxygen emission spectral lines were observed by Medium Resolution Echelle Spectrograph (MRES) at 2.4-m diameter telescope at Thai National Observatory, Inthanon Mountain, Chiang Mai, Thailand, during 1-5 LT on 5 and 6 February 2017. The observed spectral lines were calibrated via Dech95 - 2D image processing program and Dech-Fits spectra processing program for spectrum image processing and spectrum wavelength calibration, respectively. The variations of observed intensities each day were compared with solar wind parameters, which are magnitude of IMF (|BIMF|) including IMF in RTN coordinate (BR, BT, BN), ion density (ρ), plasma flow pressure (P), and speed (v). The correlation coefficients between oxygen spectral emissions and different solar wind parameters were found to vary in both positive and negative behaviors.

  6. Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

    Science.gov (United States)

    Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

    2013-07-01

    The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

  7. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    International Nuclear Information System (INIS)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi; Xie, Yanqiong; Xu, Xiaojun

    2015-01-01

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector

  8. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi [SIGMA Weather Group, State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Xie, Yanqiong [College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing (China); Xu, Xiaojun, E-mail: pbzuo@spaceweather.ac.cn, E-mail: fengx@spaceweather.ac.cn [Space Science Institute, Macau University of Science and Technology, Macao (China)

    2015-10-20

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector.

  9. Charge carrier dynamics and surface plasmon interaction in gold nanorod-blended organic solar cell

    International Nuclear Information System (INIS)

    Rana, Aniket; Lochan, Abhiram; Chand, Suresh; Kumar, Mahesh; Singh, Rajiv K.; Gupta, Neeraj; Sharma, G. D.

    2016-01-01

    The inclusion of plasmonic nanoparticles into organic solar cell enhances the light harvesting properties that lead to higher power conversion efficiency without altering the device configuration. This work defines the consequences of the nanoparticle overloading amount and energy transfer process between gold nanorod and polymer (active matrix) in organic solar cells. We have studied the hole population decay dynamics coupled with gold nanorods loading amount which provides better understanding about device performance limiting factors. The exciton and plasmon together act as an interacting dipole; however, the energy exchange between these two has been elucidated via plasmon resonance energy transfer (PRET) mechanism. Further, the charge species have been identified specifically with respect to their energy levels appearing in ultrafast time domain. The specific interaction of these charge species with respective surface plasmon resonance mode, i.e., exciton to transverse mode of oscillation and polaron pair to longitudinal mode of oscillations, has been explained. Thus, our analysis reveals that PRET enhances the carrier population density in polymer via non-radiative process beyond the concurrence of a particular plasmon resonance oscillation mode and polymer absorption range. These findings give new insight and reveal specifically the factors that enhance and control the performance of gold nanorods blended organic solar cells. This work would lead in the emergence of future plasmon based efficient organic electronic devices.

  10. Charge carrier dynamics and surface plasmon interaction in gold nanorod-blended organic solar cell

    Science.gov (United States)

    Rana, Aniket; Gupta, Neeraj; Lochan, Abhiram; Sharma, G. D.; Chand, Suresh; Kumar, Mahesh; Singh, Rajiv K.

    2016-08-01

    The inclusion of plasmonic nanoparticles into organic solar cell enhances the light harvesting properties that lead to higher power conversion efficiency without altering the device configuration. This work defines the consequences of the nanoparticle overloading amount and energy transfer process between gold nanorod and polymer (active matrix) in organic solar cells. We have studied the hole population decay dynamics coupled with gold nanorods loading amount which provides better understanding about device performance limiting factors. The exciton and plasmon together act as an interacting dipole; however, the energy exchange between these two has been elucidated via plasmon resonance energy transfer (PRET) mechanism. Further, the charge species have been identified specifically with respect to their energy levels appearing in ultrafast time domain. The specific interaction of these charge species with respective surface plasmon resonance mode, i.e., exciton to transverse mode of oscillation and polaron pair to longitudinal mode of oscillations, has been explained. Thus, our analysis reveals that PRET enhances the carrier population density in polymer via non-radiative process beyond the concurrence of a particular plasmon resonance oscillation mode and polymer absorption range. These findings give new insight and reveal specifically the factors that enhance and control the performance of gold nanorods blended organic solar cells. This work would lead in the emergence of future plasmon based efficient organic electronic devices.

  11. Dynamic window daylighting systems: electropolymeric technology for solar responsive building envelopes

    Science.gov (United States)

    Krietemeyer, Elizabeth A.; Smith, Shane I.; Dyson, Anna H.

    2011-04-01

    Human health and energy problems associated with the lack of control of sunlight in contemporary buildings have necessitated research into dynamic windows for energy efficient buildings. Existing window technologies have made moderate progress towards greater energy performance for facades but remain limited in their response to dynamic solar conditions, building energy requirements, and variable user preferences for visual comfort. Recent developments in electropolymeric display technology provide opportunities to transfer electroactive polymers to windows that can achieve high levels of geometric and spectral selectivity through the building envelope in order to meet the lighting, thermal and user requirements of occupied spaces. Experimental simulations that investigate daylight quality, energy performance, and architectural effects of electropolymeric glazing technology are presented.

  12. The comparison of solar water heating system operation parameters calculated using traditional method and dynamic simulations

    Directory of Open Access Journals (Sweden)

    Sornek Krzysztof

    2016-01-01

    Full Text Available The proper design of renewable energy based systems is really important to provide their efficient and safe operation. The aim of this paper is to compare the results obtained during traditional static calculations, with the results of dynamic simulations. For this reason, simulations of solar water heating (SWH system, designed for a typical residential building, were conducted in the TRNSYS (Transient System Simulation Tool. Carried out calculations allowed to determine the heat generation in the discussed system as well as to estimate the efficiency of considered installation. Obtained results were compared with the results from other available tool based on the static calculations. It may be concluded, that using dynamic simulations at the designing stage of renewable energy based systems may help to avoid many exploitation problems (including low efficiency, overheating etc. and allows to provide safe exploitation of such installations.

  13. MERIDIONAL CIRCULATION DYNAMICS FROM 3D MAGNETOHYDRODYNAMIC GLOBAL SIMULATIONS OF SOLAR CONVECTION

    International Nuclear Information System (INIS)

    Passos, Dário; Charbonneau, Paul; Miesch, Mark

    2015-01-01

    The form of solar meridional circulation is a very important ingredient for mean field flux transport dynamo models. However, a shroud of mystery still surrounds this large-scale flow, given that its measurement using current helioseismic techniques is challenging. In this work, we use results from three-dimensional global simulations of solar convection to infer the dynamical behavior of the established meridional circulation. We make a direct comparison between the meridional circulation that arises in these simulations and the latest observations. Based on our results, we argue that there should be an equatorward flow at the base of the convection zone at mid-latitudes, below the current maximum depth helioseismic measures can probe (0.75 R ⊙ ). We also provide physical arguments to justify this behavior. The simulations indicate that the meridional circulation undergoes substantial changes in morphology as the magnetic cycle unfolds. We close by discussing the importance of these dynamical changes for current methods of observation which involve long averaging periods of helioseismic data. Also noteworthy is the fact that these topological changes indicate a rich interaction between magnetic fields and plasma flows, which challenges the ubiquitous kinematic approach used in the vast majority of mean field dynamo simulations

  14. Full-size solar dynamic heat receiver thermal-vacuum tests

    Science.gov (United States)

    Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

    1991-01-01

    The testing of a full-size, 102 kW, solar dynamic heat receiver utilizing high-temperature thermal energy storage is described. The purpose of the test program was to quantify receiver thermodynamic performance, operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partly simulate a low-Earth-orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to allow axially and circumferentially varied flux distributions. A closed-Brayton cycle engine simulator conditioned a helium-xenon gas mixture to specific interface conditions to simulate the various operational modes of the solar dynamic power module on the Space Station Freedom. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles, each 94 minutes in duration, was completed during the test period.

  15. Ground test program for a full-size solar dynamic heat receiver

    Science.gov (United States)

    Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

    1991-01-01

    Test hardware, facilities, and procedures were developed to conduct ground testing of a full-size, solar dynamic heat receiver in a partially simulated, low earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment was designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed-Brayton cycle engine simulator to circulate and condition the helium-xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

  16. Astronomy and astrophysics communication in the UCM Observatory

    Science.gov (United States)

    Crespo-Chacón, I.; de Castro, E.; Díaz, C.; Gallego, J.; Gálvez, M. C.; Hernán-Obispo, M.; López-Santiago, J.; Montes, D.; Pascual, S.; Verdet, A.; Villar, V.; Zamorano, J.

    We present a summary of the last activities of science communication that have taken place in the Observatorio de la Universidad Complutense de Madrid (UCM Observatory) on the occasion of the Third Science Week of the Comunidad Autónoma de Madrid (3-16 November 2003), including guided tours through the observatory facilities, solar observations, and several talks. Moreover the current telescopes, instruments and tools of the UCM Observatory have allowed us to organize other communicating activities such as the live observation, together with its internet broadcast, of total lunar eclipses and other exceptional astronomical events as the Venus transit that took place in 8 June 2004.

  17. Solar Imagery - GONG (Magnetogram)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Oscillation Network Group (GONG) is a network of 6 globally-spaced solar observatories that the NOAA Space Weather Prediction Center uses to monitor the...

  18. Solar Imagery - GONG

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Oscillation Network Group (GONG) is a network of 6 globally-spaced solar observatories that the NOAA Space Weather Prediction Center uses to monitor the...

  19. Neutrino observations from the Sudbury Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Q.R.; Allen, R.C.; Andersen, T.C.; Anglin, J.D.; Barton,J.C.; Beier, E.W.; Bercovitch, M.; Bigu, J.; Biller, S.D.; Black, R.A.; Blevis, I.; Boardman, R.J.; Boger, J.; Bonvin, E.; Boulay, M.G.; Bowler,M.G.; Bowles, T.J.; Brice, S.J.; Browne, M.C.; Bullard, T.V.; Buhler, G.; Cameron, J.; Chan, Y.D.; Chen, H.H.; Chen, M.; Chen, X.; Cleveland, B.T.; Clifford, E.T.H.; Cowan, J.H.M.; Cowen, D.F.; Cox, G.A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W.F.; Doe, P.J.; Doucas, G.; Dragowsky,M.R.; Duba, C.A.; Duncan, F.A.; Dunford, M.; Dunmore, J.A.; Earle, E.D.; Elliott, S.R.; Evans, H.C.; Ewan, G.T.; Farine, J.; Fergani, H.; Ferraris, A.P.; Ford, R.J.; Formaggio, J.A.; Fowler, M.M.; Frame, K.; Frank, E.D.; Frati, W.; Gagnon, N.; Germani, J.V.; Gil, S.; Graham, K.; Grant, D.R.; Hahn, R.L.; Hallin, A.L.; Hallman, E.D.; Hamer, A.S.; Hamian, A.A.; Handler, W.B.; Haq, R.U.; Hargrove, C.K.; Harvey, P.J.; Hazama, R.; Heeger, K.M.; Heintzelman, W.J.; Heise, J.; Helmer, R.L.; Hepburn, J.D.; Heron, H.; Hewett, J.; Hime, A.; Hykawy, J.G.; Isaac,M.C.P.; Jagam, P.; Jelley, N.A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P.T.; Klein, J.R.; Knox, A.B.; Komar, R.J.; Kouzes, R.; Kutter,T.; Kyba, C.C.M.; Law, J.; Lawson, I.T.; Lay, M.; Lee, H.W.; Lesko, K.T.; Leslie, J.R.; Levine, I.; Locke, W.; Luoma, S.; Lyon, J.; Majerus, S.; Mak, H.B.; Maneira, J.; Manor, J.; Marino, A.D.; McCauley, N.; McDonald,D.S.; McDonald, A.B.; McFarlane, K.; McGregor, G.; Meijer, R.; Mifflin,C.; Miller, G.G.; Milton, G.; Moffat, B.A.; Moorhead, M.; Nally, C.W.; Neubauer, M.S.; Newcomer, F.M.; Ng, H.S.; Noble, A.J.; Norman, E.B.; Novikov, V.M.; O' Neill, M.; Okada, C.E.; Ollerhead, R.W.; Omori, M.; Orrell, J.L.; Oser, S.M.; Poon, A.W.P.; Radcliffe, T.J.; Roberge, A.; Robertson, B.C.; Robertson, R.G.H.; Rosendahl, S.S.E.; Rowley, J.K.; Rusu, V.L.; Saettler, E.; Schaffer, K.K.; Schwendener,M.H.; Schulke, A.; Seifert, H.; Shatkay, M.; Simpson, J.J.; Sims, C.J.; et al.

    2001-09-24

    The Sudbury Neutrino Observatory (SNO) is a water imaging Cherenkov detector. Its usage of 1000 metric tons of D{sub 2}O as target allows the SNO detector to make a solar-model independent test of the neutrino oscillation hypothesis by simultaneously measuring the solar {nu}{sub e} flux and the total flux of all active neutrino species. Solar neutrinos from the decay of {sup 8}B have been detected at SNO by the charged-current (CC) interaction on the deuteron and by the elastic scattering (ES) of electrons. While the CC reaction is sensitive exclusively to {nu}{sub e}, the ES reaction also has a small sensitivity to {nu}{sub {mu}} and {nu}{sub {tau}}. In this paper, recent solar neutrino results from the SNO experiment are presented. It is demonstrated that the solar flux from {sup 8}B decay as measured from the ES reaction rate under the no-oscillation assumption is consistent with the high precision ES measurement by the Super-Kamiokande experiment. The {nu}{sub e} flux deduced from the CC reaction rate in SNO differs from the Super-Kamiokande ES results by 3.3{sigma}. This is evidence for an active neutrino component, in additional to {nu}{sub e}, in the solar neutrino flux. These results also allow the first experimental determination of the total active {sup 8}B neutrino flux from the Sun, and is found to be in good agreement with solar model predictions.

  20. Neutrino Observations from the Sudbury Neutrino Observatory

    Science.gov (United States)

    Q. R. Ahmad, R. C. Allen, T. C. Andersen, J. D. Anglin, G. B?hler, J. C. Barton, E. W. Beier, M. Bercovitch, J. Bigu, S. Biller, R. A. Black, I. Blevis, R. J. Boardman, J. Boger, E. Bonvin, M. G. Boulay, M. G. Bowler, T. J. Bowles, S. J. Brice, M. C. Browne, T. V. Bullard, T. H. Burritt, K. Cameron, J. Cameron, Y. D. Chan, M. Chen, H. H. Chen, X. Chen, M. C. Chon, B. T. Cleveland, E. T. H. Clifford, J. H. M. Cowan, D. F. Cowen, G. A. Cox, Y. Dai, X. Dai, F. Dalnoki-Veress, W. F. Davidson, P. J. Doe, G. Doucas, M. R. Dragowsky, C. A. Duba, F. A. Duncan, J. Dunmore, E. D. Earle, S. R. Elliott, H. C. Evans, G. T. Ewan, J. Farine, H. Fergani, A. P. Ferraris, R. J. Ford, M. M. Fowler, K. Frame, E. D. Frank, W. Frati, J. V. Germani, S. Gil, A. Goldschmidt, D. R. Grant, R. L. Hahn, A. L. Hallin, E. D. Hallman, A. Hamer, A. A. Hamian, R. U. Haq, C. K. Hargrove, P. J. Harvey, R. Hazama, R. Heaton, K. M. Heeger, W. J. Heintzelman, J. Heise, R. L. Helmer, J. D. Hepburn, H. Heron, J. Hewett, A. Hime, M. Howe, J. G. Hykawy, M. C. P. Isaac, P. Jagam, N. A. Jelley, C. Jillings, G. Jonkmans, J. Karn, P. T. Keener, K. Kirch, J. R. Klein, A. B. Knox, R. J. Komar, R. Kouzes, T. Kutter, C. C. M. Kyba, J. Law, I. T. Lawson, M. Lay, H. W. Lee, K. T. Lesko, J. R. Leslie, I. Levine, W. Locke, M. M. Lowry, S. Luoma, J. Lyon, S. Majerus, H. B. Mak, A. D. Marino, N. McCauley, A. B. McDonald, D. S. McDonald, K. McFarlane, G. McGregor, W. McLatchie, R. Meijer Drees, H. Mes, C. Mifflin, G. G. Miller, G. Milton, B. A. Moffat, M. Moorhead, C. W. Nally, M. S. Neubauer, F. M. Newcomer, H. S. Ng, A. J. Noble, E. B. Norman, V. M. Novikov, M. O'Neill, C. E. Okada, R. W. Ollerhead, M. Omori, J. L. Orrell, S. M. Oser, A. W. P. Poon, T. J. Radcliffe, A. Roberge, B. C. Robertson, R. G. H. Robertson, J. K. Rowley, V. L. Rusu, E. Saettler, K. K. Schaffer, A. Schuelke, M. H. Schwendener, H. Seifert, M. Shatkay, J. J. Simpson, D. Sinclair, P. Skensved, A. R. Smith, M. W. E. Smith, N. Starinsky, T. D. Steiger, R. G. Stokstad, R. S. Storey, B. Sur, R. Tafirout, N. Tagg, N. W. Tanner, R. K. Taplin, M. Thorman, P. Thornewell, P. T. Trent, Y. I. Tserkovnyak, R. Van Berg, R. G. Van de Water, C. J. Virtue, C. E. Waltham, J.-X. Wang, D. L. Wark, N. West, J. B. Wilhelmy, J. F. Wilkerson, J. Wilson, P. Wittich, J. M. Wouters, and M. Yeh

    2001-09-24

    The Sudbury Neutrino Observatory (SNO) is a water imaging Cherenkov detector. Its usage of 1000 metric tons of D{sub 2}O as target allows the SNO detector to make a solar-model independent test of the neutrino oscillation hypothesis by simultaneously measuring the solar {nu}{sub e} flux and the total flux of all active neutrino species. Solar neutrinos from the decay of {sup 8}B have been detected at SNO by the charged-current (CC) interaction on the deuteron and by the elastic scattering (ES) of electrons. While the CC reaction is sensitive exclusively to {nu}{sub e}, the ES reaction also has a small sensitivity to {nu}{sub {mu}} and {nu}{sub {tau}}. In this paper, recent solar neutrino results from the SNO experiment are presented. It is demonstrated that the solar flux from {sup 8}B decay as measured from the ES reaction rate under the no-oscillation assumption is consistent with the high precision ES measurement by the Super-Kamiokande experiment. The {nu}{sub e} flux deduced from the CC reaction rate in SNO differs from the Super-Kamiokande ES results by 3.3{sigma}. This is evidence for an active neutrino component, in additional to {nu}{sub e}, in the solar neutrino flux. These results also allow the first experimental determination of the total active {sup 8}B neutrino flux from the Sun, and is found to be in good agreement with solar model predictions.

  1. A PROPOSED PARADIGM FOR SOLAR CYCLE DYNAMICS MEDIATED VIA TURBULENT PUMPING OF MAGNETIC FLUX IN BABCOCK–LEIGHTON-TYPE SOLAR DYNAMOS

    Energy Technology Data Exchange (ETDEWEB)

    Hazra, Soumitra; Nandy, Dibyendu [Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata (India)

    2016-11-20

    At present, the Babcock–Leighton flux transport solar dynamo models appear to be the most promising models for explaining diverse observational aspects of the sunspot cycle. The success of these flux transport dynamo models is largely dependent upon a single-cell meridional circulation with a deep equatorward component at the base of the Sun’s convection zone. However, recent observations suggest that the meridional flow may in fact be very shallow (confined to the top 10% of the Sun) and more complex than previously thought. Taken together, these observations raise serious concerns on the validity of the flux transport paradigm. By accounting for the turbulent pumping of magnetic flux, as evidenced in magnetohydrodynamic simulations of solar convection, we demonstrate that flux transport dynamo models can generate solar-like magnetic cycles even if the meridional flow is shallow. Solar-like periodic reversals are recovered even when meridional circulation is altogether absent. However, in this case, the solar surface magnetic field dynamics does not extend all the way to the polar regions. Very importantly, our results demonstrate that the Parker–Yoshimura sign rule for dynamo wave propagation can be circumvented in Babcock–Leighton dynamo models by the latitudinal component of turbulent pumping, which can generate equatorward propagating sunspot belts in the absence of a deep, equatorward meridional flow. We also show that variations in turbulent pumping coefficients can modulate the solar cycle amplitude and periodicity. Our results suggest the viability of an alternate magnetic flux transport paradigm—mediated via turbulent pumping—for sustaining solar-stellar dynamo action.

  2. A PROPOSED PARADIGM FOR SOLAR CYCLE DYNAMICS MEDIATED VIA TURBULENT PUMPING OF MAGNETIC FLUX IN BABCOCK–LEIGHTON-TYPE SOLAR DYNAMOS

    International Nuclear Information System (INIS)

    Hazra, Soumitra; Nandy, Dibyendu

    2016-01-01

    At present, the Babcock–Leighton flux transport solar dynamo models appear to be the most promising models for explaining diverse observational aspects of the sunspot cycle. The success of these flux transport dynamo models is largely dependent upon a single-cell meridional circulation with a deep equatorward component at the base of the Sun’s convection zone. However, recent observations suggest that the meridional flow may in fact be very shallow (confined to the top 10% of the Sun) and more complex than previously thought. Taken together, these observations raise serious concerns on the validity of the flux transport paradigm. By accounting for the turbulent pumping of magnetic flux, as evidenced in magnetohydrodynamic simulations of solar convection, we demonstrate that flux transport dynamo models can generate solar-like magnetic cycles even if the meridional flow is shallow. Solar-like periodic reversals are recovered even when meridional circulation is altogether absent. However, in this case, the solar surface magnetic field dynamics does not extend all the way to the polar regions. Very importantly, our results demonstrate that the Parker–Yoshimura sign rule for dynamo wave propagation can be circumvented in Babcock–Leighton dynamo models by the latitudinal component of turbulent pumping, which can generate equatorward propagating sunspot belts in the absence of a deep, equatorward meridional flow. We also show that variations in turbulent pumping coefficients can modulate the solar cycle amplitude and periodicity. Our results suggest the viability of an alternate magnetic flux transport paradigm—mediated via turbulent pumping—for sustaining solar-stellar dynamo action.

  3. Geomagnetic secular variation at the African observatories

    International Nuclear Information System (INIS)

    Haile, T.

    2002-10-01

    Geomagnetic data from ten observatories in the African continent with time series data length of more than three decades have been analysed. All-day annual mean values of the D, H and Z components were used to study secular variations in the African region. The residuals in D, H and Z components obtained after removing polynomial fits have been examined in relation to the sunspot cycle. The occurrence of the 1969-1970 worldwide geomagnetic impulse in each observatory is studied. It is found that the secular variation in the field can be represented for most of the observatories with polynomials of second or third degree. Departures from these trends are observed over the Southern African region where strong local magnetic anomalies have been observed. The residuals in the geomagnetic field components have been shown to exhibit parallelism with the periods corresponding to double solar cycle for some of the stations. A clear latitudinal distribution in the geomagnetic component that exhibits the 1969-70 jerk is shown. The jerk appears in the plots of the first differences in H for the southern most observatories of Hermanus, Hartebeesthoek, and Tsuemb, while the Z plots show the jerk for near equatorial and equatorial stations of Antananarivo, Luanda Belas, Bangui and Addis Ababa. There is some indication for this jerk in the first difference plots of D for the northern stations of M'Bour and Tamanrasset. The plots of D rather strongly suggest the presence of a jerk around 1980 at most of the stations. (author)

  4. Simulation analysis on dynamic performance of a combined solar/air dual source heat pump water heater

    International Nuclear Information System (INIS)

    Deng, Weishi; Yu, Jianlin

    2016-01-01

    Highlights: • A modified direct expansion solar-assisted heat pump water heater is investigated. • An additional air source evaporator is used in parallel way in the M-DX-SHPWH system. • The M-DX-SHPWH system displays a higher performance at the low solar radiation. • Effects of solar radiation and air temperature on the performance are discussed. - Abstract: This paper investigated a combined solar/air dual source heat pump water heater system for domestic water heating application. In the dual source system, an additional air source evaporator is introduced in parallel way based on a conventional direct expansion solar-assisted heat pump water heaters (DX-SHPWH) system, which can improve the performance of the DX-SHPWH system at a low solar radiation. In the present study, a dynamic mathematical model based on zoned lump parameter approach is developed to simulate the performance of the system (i.e. a modified DX-SHPWH (M-DX-SHPWH) system). Using the model, the performance of M-DX-SHPWH system is evaluated and then compared with that of the conventional DX-SHPWH system. The simulation results show the M-DX-SHPWH system has a better performance than that of the conventional DX-SHPWH system. At a low solar radiation of 100 W/m"2, the heating time of the M-DX-SHPWH decreases by 19.8% compared to the DX-SHPWH when water temperature reaches 55 °C. Meanwhile, the COP on average increases by 14.1%. In addition, the refrigerant mass flow rate distribution in the air source evaporator and the solar collector of the system, the allocation between the air source evaporator and the solar collector areas and effects of solar radiation and ambient air temperature on the system performance are discussed.

  5. The Coupled Orbit-Attitude Dynamics and Control of Electric Sail in Displaced Solar Orbits

    Directory of Open Access Journals (Sweden)

    Mingying Huo

    2017-01-01

    Full Text Available Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

  6. US Naval Observatory Hourly Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly observations journal from the National Observatory in Washington DC. The observatory is the first station in the United States to produce hourly observations...

  7. Magnetosphere and ionosphere response to a positive-negative pulse pair of solar wind dynamic pressure

    Science.gov (United States)

    Tian, A.; Degeling, A. W.

    2017-12-01

    Simulations and observations had shown that single positive/negative solar wind dynamic pressure pulse would excite geomagnetic impulsive events along with ionosphere and/or magnetosphere vortices which are connected by field aligned currents(FACs). In this work, a large scale ( 9min) magnetic hole event in solar wind provided us with the opportunity to study the effects of positive-negative pulse pair (△p/p 1) on the magnetosphere and ionosphere. During the magnetic hole event, two traveling convection vortices (TCVs, anti-sunward) first in anticlockwise then in clockwise rotation were detected by geomagnetic stations located along the 10:30MLT meridian. At the same time, another pair of ionospheric vortices azimuthally seen up to 3 MLT first in clockwise then in counter-clockwise rotation were also appeared in the afternoon sector( 14MLT) and centered at 75 MLAT without obvious tailward propagation feature. The duskside vortices were also confirmed in SuperDARN radar data. We simulated the process of magnetosphere struck by a positive-negative pulse pair and it shows that a pair of reversed flow vortices in the magnetosphere equatorial plane appeared which may provide FACs for the vortices observed in ionosphere. Dawn dusk asymmetry of the vortices as well as the global geomagnetism perturbation characteristics were also discussed.

  8. A dynamic Monte Carlo study of anomalous current voltage behaviour in organic solar cells

    International Nuclear Information System (INIS)

    Feron, K.; Fell, C. J.; Zhou, X.; Belcher, W. J.; Dastoor, P. C.

    2014-01-01

    We present a dynamic Monte Carlo (DMC) study of s-shaped current-voltage (I-V) behaviour in organic solar cells. This anomalous behaviour causes a substantial decrease in fill factor and thus power conversion efficiency. We show that this s-shaped behaviour is induced by charge traps that are located at the electrode interface rather than in the bulk of the active layer, and that the anomaly becomes more pronounced with increasing trap depth or density. Furthermore, the s-shape anomaly is correlated with interface recombination, but not bulk recombination, thus highlighting the importance of controlling the electrode interface. While thermal annealing is known to remove the s-shape anomaly, the reason has been not clear, since these treatments induce multiple simultaneous changes to the organic solar cell structure. The DMC modelling indicates that it is the removal of aluminium clusters at the electrode, which act as charge traps, that removes the anomalous I-V behaviour. Finally, this work shows that the s-shape becomes less pronounced with increasing electron-hole recombination rate; suggesting that efficient organic photovoltaic material systems are more susceptible to these electrode interface effects

  9. Image-based reconstruction of the Newtonian dynamics of solar coronal ejecta

    Science.gov (United States)

    Uritsky, Vadim M.; Thompson, Barbara J.

    2016-10-01

    We present a new methodology for analyzing rising and falling dynamics of unstable coronal material as represented by high-cadence SDO AIA images. The technique involves an adaptive spatiotemporal tracking of propagating intensity gradients and their characterization in terms of time-evolving areas swept out by the position vector originated from the Sun disk center. The measured values of the areal velocity and acceleration are used to obtain quantitative information on the angular momentum and acceleration along the paths of the rising and falling coronal plasma. In the absence of other forces, solar gravitation results in purely ballistic motions consistent with the Kepler's second law; non-central forces such as the Lorentz force introduce non-zero torques resulting in more complex motions. The developed algorithms enable direct evaluation of the line-of-sight component of the net torque applied to a unit mass of the ejected coronal material which is proportional to the image-plane projection of the observed areal acceleration. The current implementation of the method cannot reliably distinguish torque modulations caused by the coronal force field from those imposed by abrupt changes of plasma mass density and nontrivial projection effects. However, it can provide valid observational constraints on the evolution of large-scale unstable magnetic topologies driving major solar-coronal eruptions as demonstrated in the related talk by B. Thompson et al.

  10. Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

    Directory of Open Access Journals (Sweden)

    Ryunosuke Miyoshi

    2016-01-01

    Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

  11. Morphology and Dynamics of Solar Prominences from 3D MHD Simulations

    Science.gov (United States)

    Terradas, J.; Soler, R.; Luna, M.; Oliver, R.; Ballester, J. L.

    2015-01-01

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  12. Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model

    Directory of Open Access Journals (Sweden)

    T. R. Sun

    2012-08-01

    Full Text Available We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By. In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.

  13. MORPHOLOGY AND DYNAMICS OF SOLAR PROMINENCES FROM 3D MHD SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M., E-mail: jaume.terradas@uib.es [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

    2015-01-20

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  14. Excited state and charge-carrier dynamics in perovskite solar cell materials

    Science.gov (United States)

    Ponseca, Carlito S., Jr.; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G.

    2016-02-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research.

  15. Excited state and charge-carrier dynamics in perovskite solar cell materials

    International Nuclear Information System (INIS)

    Ponseca, Carlito S Jr; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G

    2016-01-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research. (topical review)

  16. Solar Thermal Technologies Dynamics and Strategies for Market Creation in Sindh

    Directory of Open Access Journals (Sweden)

    Asif Ali Shah

    2016-04-01

    Full Text Available In order to sketch Sindh's RE (Renewable Energy based scenario, it is vital to trace the dynamics of simplest RETs (Renewable Energy Technologies such as STTs (Solar Thermal Technologies. STTs are simple to operate, easy to maintain and requires low cost of fabrication. Due to these advantages, STTs possess scope for mass market creation in Sindh as can provide alternate energy solutions to meet daily fuel requirements of heating and cooking etc. The paper identifies that the low awareness creates a negative perception about the price and efficiency of these technologies in masses, which can be removed once the awareness increases. This paper consists of survey findings, which traces the trends for STTs utilization in Sindh by testing various hypotheses to identify the suitable tactics required for their market creation. Finally the key policy recommendations are provided at the end.

  17. Hint of nonstandard Mikheyev-Smirnov-Wolfenstein dynamics in solar neutrino conversion

    Science.gov (United States)

    Palazzo, Antonio

    2011-05-01

    Motivated by the recent low-threshold measurements of the solar B8 neutrino spectrum performed by Borexino, Super-Kamiokande and the Sudbury Neutrino Observatory—all now monitoring the transition regime between low-energy (vacuumlike) and high-energy (matter-dominated) flavor conversions—we consider the role of subdominant dynamical terms induced by new flavor-changing interactions. We find that the presence of such perturbations with strength ˜10-1GF is now favored, offering a better description of the anomalous behavior suggested by the new results, whose spectrum shows no sign of the typical low-energy upturn predicted by the standard Mikheyev-Smirnov-Wolfenstein (MSW) mechanism. Our findings, if interpreted in a 2-flavor scheme, provide a hint of such new interactions at the ˜2σ level, which is rather robust with respect to 3-flavor effects possibly induced by nonzero θ13.

  18. Investigation of Thermal Performance of Flat Plate and Evacuated Tubular Solar Collectors According to a New Dynamic Test Method

    DEFF Research Database (Denmark)

    Kong, Weiqiang; Wang, Zhifeng; Fan, Jianhua

    2012-01-01

    obtain fluid thermal capacitance in data processing. Then theoretical analysis and experimental verification are carried out to investigate influencing factors of obtaining accurate and stable second order term. A flat plate and ETC solar collector are compared using both the new dynamic method......A new dynamic test method is introduced. This so called improved transfer function method features on two new collector parameters. One is time term which can indicate solar collector's inner heat transfer ability and the other is a second order term of collector mean fluid temperature which can...... and a standard method. The results show that the improved function method can accurately and robustly estimate these two kinds of solar collectors....

  19. A NOISE ADAPTIVE FUZZY EQUALIZATION METHOD FOR PROCESSING SOLAR EXTREME ULTRAVIOLET IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Druckmueller, M., E-mail: druckmuller@fme.vutbr.cz [Institute of Mathematics, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, 616 69 Brno (Czech Republic)

    2013-08-15

    A new image enhancement tool ideally suited for the visualization of fine structures in extreme ultraviolet images of the corona is presented in this paper. The Noise Adaptive Fuzzy Equalization method is particularly suited for the exceptionally high dynamic range images from the Atmospheric Imaging Assembly instrument on the Solar Dynamics Observatory. This method produces artifact-free images and gives significantly better results than methods based on convolution or Fourier transform which are often used for that purpose.

  20. Observed Responses of Mesospheric Water Vapor to Solar Cycle and Dynamical Forcings

    Science.gov (United States)

    Remsberg, Ellis; Damadeo, Robert; Natarajan, Murali; Bhatt, Praful

    2018-04-01

    This study focuses on responses of mesospheric water vapor (H2O) to the solar cycle flux at Lyman-α wavelength and to dynamical forcings according to the multivariate El-Nino/Southern Oscillation (ENSO) index. The zonal-averaged responses are for latitudes from 60°S to 60°N and pressure-altitudes from 0.01 to 1.0 hPa, as obtained from multiple linear regression analyses of time series of H2O from the Halogen Occultation Experiment for July 1992 to November 2005. The results compare very well with those from a separate simultaneous temporal and spatial (STS) method that also confirms that there are no significant sampling biases affecting both sets of results. Distributions of the seasonal amplitudes for temperature and H2O are in accord with the seasonal net circulation. In general, the responses of H2O to ENSO are anticorrelated with those of temperature. H2O responses to multivariate ENSO index are negative in the upper mesosphere and largest in the Northern Hemisphere; responses in the lower mesosphere are more symmetric with latitude. H2O responses to the Lyman-α flux (Lya) vary from strong negative values in the uppermost mesosphere to very weak, positive values in the tropical lowermost mesosphere. However, the effects of those H2O responses to the solar activity extend to the rest of the mesosphere via dynamical processes. Profiles of the responses to ENSO and Lya also agree reasonably with published results for H2O at the low latitudes from the Microwave Limb Sounder.

  1. Experimental validation of dynamic simulation of the flat plate collector in a closed thermosyphon solar water heater

    DEFF Research Database (Denmark)

    Taherian, H.; Kolaei, Alireza Rezania; Sadeghi, S.

    2011-01-01

    This work studies the dynamic simulation of thermosyphon solar water heater collector considering the weather conditions of a city in north of Iran. The simulation was done for clear and partly cloudy days. The useful energy, the efficiency diagrams, the inlet and the outlet of collector, center...

  2. Response of the middle atmosphere to solar UV and dynamical perturbations

    International Nuclear Information System (INIS)

    Chandra, S.

    1989-01-01

    Recent studies of solar UV related changes of ozone and temperature have considerably improved the understanding of the solar UV and ozone relationship in the middle atmosphere on time scales of a solar rotation. These studies have shown that during periods of high solar activity, ozone in the upper stratosphere has a measurable response to changes in the solar UV flux in accordance with theoretical predictions. The problem of measuring solar response of the stratospheric ozone and temperature on time scales of a solar cycle is more difficult. In the altitude range of 2 mb, the model based calculations, based on plausible scenarios of solar UV variation, suggest a change of less than 4 percent in ozone mixing ratio and 1 to 2 K in temperature. The relative response was studied of the middle atmosphere to solar forcing at 155 and 27 day periods as indicated from the spectral analyses of a number of solar indices

  3. Extreme Worlds of the Outer Solar System: Dynamic Processes on Uranus & Io

    Science.gov (United States)

    Kleer, Katherine Rebecca de

    A central goal of planetary science is the creation of a framework within which the properties of each solar system body can be understood as the product of initial conditions acted on by fundamental physical processes. The solar system's extreme worlds -- those objects that lie at the far ends of the spectrum in terms of planetary environment -- bring to light our misconceptions and present us with opportunities to expand and generalize this framework. Unraveling the processes at work in diverse planetary environments contextualizes our understanding of Earth, and provides a basis for interpreting specific signatures from planets beyond our own solar system. Uranus and Io, with their unusual planetary environments, present two examples of such worlds in the outer solar system. Uranus, one of the outer solar system's ice giants, produces an anomalously low heat flow and orbits the sun on its side. Its relative lack of bright storm features and its bizarre multi-decadal seasons provide insight into the relative effects of internal heat flow and time- varying solar insolation on atmospheric dynamics, while its narrow rings composed of dark, macroscopic particles encode the history of bombardment and satellite disruption within the system. Jupiter's moon Io hosts the most extreme volcanic activity anywhere in the solar system. Its tidally-powered geological activity provides a window into this satellite's interior, permitting rare and valuable investigations into the exchange of heat and materials between interiors and surfaces. In particular, Io provides a laboratory for studying the process of tidal heating, which shapes planets and satellites in our solar system and beyond. A comparison between Earth and Io contextualizes the volcanism at work on our home planet, revealing the effects of planetary size, atmospheric density, and plate tectonics on the style and mechanisms of geological activity. This dissertation investigates the processes at work on these solar

  4. 3D Visualization of Solar Data: Preparing for Solar Orbiter and Parker Solar Probe

    Science.gov (United States)

    Mueller, D.; Nicula, B.; Felix, S.; Verstringe, F.; Bourgoignie, B.; Csillaghy, A.; Berghmans, D.; Jiggens, P.; Ireland, J.; Fleck, B.

    2017-12-01

    Solar Orbiter and Parker Solar Probe will focus on exploring the linkage between the Sun and the heliosphere. These new missions will collect unique data that will allow us to study, e.g., the coupling between macroscopic physical processes to those on kinetic scales, the generation of solar energetic particles and their propagation into the heliosphere and the origin and acceleration of solar wind plasma. Combined with the several petabytes of data from NASA's Solar Dynamics Observatory, the scientific community will soon have access to multi­dimensional remote-sensing and complex in-situ observations from different vantage points, complemented by petabytes of simulation data. Answering overarching science questions like "How do solar transients drive heliospheric variability and space weather?" will only be possible if the community has the necessary tools at hand. In this contribution, we will present recent progress in visualizing the Sun and its magnetic field in 3D using the open-source JHelioviewer framework, which is part of the ESA/NASA Helioviewer Project.

  5. The solar energetic particle event on 2013 April 11: an investigation of its solar origin and longitudinal spread

    Energy Technology Data Exchange (ETDEWEB)

    Lario, D.; Raouafi, N. E. [The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723 (United States); Kwon, R.-Y.; Zhang, J. [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 6A2, Fairfax, VA 22030 (United States); Gómez-Herrero, R. [Space Research Group, Physics and Mathematics Department, University of Alcalá, Alcalá de Henares, E-28871 Spain (Spain); Dresing, N. [Institute of Experimental and Applied Physics, Christian-Albrechts University of Kiel, Kiel D-24118 (Germany); Riley, P. [Predictive Science, 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States)

    2014-12-10

    We investigate the solar phenomena associated with the origin of the solar energetic particle (SEP) event observed on 2013 April 11 by a number of spacecraft distributed in the inner heliosphere over a broad range of heliolongitudes. We use extreme ultraviolet (EUV) and white-light coronagraph observations from the Solar Dynamics Observatory (SDO), the SOlar and Heliospheric Observatory, and the twin Solar TErrestrial RElations Observatory spacecraft (STEREO-A and STEREO-B) to determine the angular extent of the EUV wave and coronal mass ejection (CME) associated with the origin of the SEP event. We compare the estimated release time of SEPs observed at each spacecraft with the arrival time of the structures associated with the CME at the footpoints of the field lines connecting each spacecraft with the Sun. Whereas the arrival of the EUV wave and CME-driven shock at the footpoint of STEREO-B is consistent, within uncertainties, with the release time of the particles observed by this spacecraft, the EUV wave never reached the footpoint of the field lines connecting near-Earth observers with the Sun, even though an intense SEP event was observed there. We show that the west flank of the CME-driven shock propagating at high altitudes above the solar surface was most likely the source of the particles observed near Earth, but it did not leave any EUV trace on the solar disk. We conclude that the angular extent of the EUV wave on the solar surface did not agree with the longitudinal extent of the SEP event in the heliosphere. Hence EUV waves cannot be used reliably as a proxy for the solar phenomenon that accelerates and injects energetic particles over broad ranges of longitudes.

  6. Single Molecule Spectroelectrochemistry of Interfacial Charge Transfer Dynamics In Hybrid Organic Solar Cell

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Shanlin [Univ. of Alabama, Tuscaloosa, AL (United States)

    2014-11-16

    Our research under support of this DOE grant is focused on applied and fundamental aspects of model organic solar cell systems. Major accomplishments are: 1) we developed a spectroelectorchemistry technique of single molecule single nanoparticle method to study charge transfer between conjugated polymers and semiconductor at the single molecule level. The fluorescence of individual fluorescent polymers at semiconductor surfaces was shown to exhibit blinking behavior compared to molecules on glass substrates. Single molecule fluorescence excitation anisotropy measurements showed the conformation of the polymer molecules did not differ appreciably between glass and semiconductor substrates. The similarities in molecular conformation suggest that the observed differences in blinking activity are due to charge transfer between fluorescent polymer and semiconductor, which provides additional pathways between states of high and low fluorescence quantum efficiency. Similar spectroelectrochemistry work has been done for small organic dyes for understand their charge transfer dynamics on various substrates and electrochemical environments; 2) We developed a method of transferring semiconductor nanoparticles (NPs) and graphene oxide (GO) nanosheets into organic solvent for a potential electron acceptor in bulk heterojunction organic solar cells which employed polymer semiconductor as the electron donor. Electron transfer from the polymer semiconductor to semiconductor and GO in solutions and thin films was established through fluorescence spectroscopy and electroluminescence measurements. Solar cells containing these materials were constructed and evaluated using transient absorption spectroscopy and dynamic fluorescence techniques to understand the charge carrier generation and recombination events; 3) We invented a spectroelectorchemistry technique using light scattering and electroluminescence for rapid size determination and studying electrochemistry of single NPs in an

  7. Dynamic response of a modified water tank exposed to concentrated solar energy

    Science.gov (United States)

    Alhamdo, M. H.; Alkhakani, A. J.

    2017-08-01

    Power generation by using concentrated solar thermal energy on liquid enclosures is one of the most promising renewable energy technologies. In this work, a developed liquid enclosure fitted with various number and configurations of horizontal metal rings have been analyzed, fabricated and tested. The influence of adding metal rings arrangement is investigated for its potential to enhance radial heat conduction to the center-line of the enclosure from the side-walls. Experiments were carried out for fluid in both static and dynamic modes of operation inside the enclosure that subjected to high heat flux. A developed two-dimensional CFD model to predict the transient flow and thermal fields within liquid enclosure subjected to heat flux has been developed and tested. The developed numerical model takes into consideration energy transport between the liquid inside enclosure and the solid material of the enclosure. The numerical simulations have been compared with experimental measurement. The computational code has been found in a good level of agreement with the experimental data except for liquid at the peak part of the enclosure. The results indicate that adding metal rings produce significant impact on the transient temperature difference inside enclosure during both static and dynamic modes. The six-ring model is found to be more effective for enhancing radial heat transfer than other three models that have been tested. The in-line arrangement is found to provide better thermal effect as compared to the staggered rings. Two new correlations for natural heat transfer inside liquid enclosures subjected to high heat flux have been formulated (one for no-ring model and the other for six-ring model). The natural Nusselt number is found to be around a constant value for Rayleigh number less than (5 X 108). The recommended use of metal rings inside liquid enclosures subjected to heat flux, and the predicted Nusselt number correlation, will add to local knowledge a

  8. Expanding the HAWC Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Johanna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-17

    The High Altitude Water Cherenkov Gamma-Ray Observatory is expanding its current array of 300 water tanks to include 350 outrigger tanks to increase sensitivity to gamma rays above 10 TeV. This involves creating and testing hardware with which to build the new tanks, including photomultiplier tubes, high voltage supply units, and flash analog to digital converters. My responsibilities this summer included preparing, testing and calibrating that equipment.

  9. STRUCTURE AND DYNAMICS OF THE 2010 JULY 11 ECLIPSE WHITE-LIGHT CORONA

    International Nuclear Information System (INIS)

    Pasachoff, J. M.; Rusin, V.; Saniga, M.

    2011-01-01

    The white-light corona (WLC) during the total solar eclipse on 2010 July 11 was observed by several teams in the Moon's shadow stretching across the Pacific Ocean and a number of isolated islands. We present a comparison of the WLC as observed by eclipse teams located on the Tatakoto Atoll in French Polynesia and on Easter Island, 83 minutes later, combined with near-simultaneous space observations. The eclipse was observed at the beginning of the solar cycle, not long after solar minimum. Nevertheless, the solar corona shows a plethora of different features (coronal holes, helmet streamers, polar rays, very faint loops and radial-oriented thin streamers, a coronal mass ejection, and a puzzling 'curtain-like' object above the north pole). Comparing the observations from the two sites enables us to detect some dynamic phenomena. The eclipse observations are further compared with a hairy-ball model of the magnetic field and near-simultaneous images from the Atmospheric Imaging Assembly on NASA's Solar Dynamics Observatory, the Extreme Ultraviolet Imager on NASA's Solar Terrestrial Relations Observatory, the Sun Watcher, using Active Pixel System Detector and Image Processing on ESA's PRoject for Onboard Autonomy, and the Naval Research Laboratory's Large Angle and Spectrometric Coronagraph on ESA's Solar and Heliospheric Observatory. The Ludendorff flattening coefficient is 0.156, matching the expected ellipticity of coronal isophotes at 2 Rs un , for this rising phase of the solar-activity cycle.

  10. Solar Irradiance Variability is Caused by the Magnetic Activity on the Solar Surface.

    Science.gov (United States)

    Yeo, Kok Leng; Solanki, Sami K; Norris, Charlotte M; Beeck, Benjamin; Unruh, Yvonne C; Krivova, Natalie A

    2017-09-01

    The variation in the radiative output of the Sun, described in terms of solar irradiance, is important to climatology. A common assumption is that solar irradiance variability is driven by its surface magnetism. Verifying this assumption has, however, been hampered by the fact that models of solar irradiance variability based on solar surface magnetism have to be calibrated to observed variability. Making use of realistic three-dimensional magnetohydrodynamic simulations of the solar atmosphere and state-of-the-art solar magnetograms from the Solar Dynamics Observatory, we present a model of total solar irradiance (TSI) that does not require any such calibration. In doing so, the modeled irradiance variability is entirely independent of the observational record. (The absolute level is calibrated to the TSI record from the Total Irradiance Monitor.) The model replicates 95% of the observed variability between April 2010 and July 2016, leaving little scope for alternative drivers of solar irradiance variability at least over the time scales examined (days to years).

  11. Solar Physics Topics in High School: Analysis of a Course with Practical Activities at Dietrich Schiel Observatory. (Spanish Title: Temas de Física Solar Para Estudiantes de Escuelas Secundarias: un Análisis de un Curso con Enfoque Práctico en el Observatorio Dietrich Schiel.) Tópicos de Física Solar no Ensino Médio: Análise de um Curso com Atividades Práticas no Observatório Dietrich Schiel

    Science.gov (United States)

    Calbo Aroca, Silvia; Donizete Colombo, Pedro, Jr.; Celestino Silva, Cibelle

    2012-12-01

    This work analyses results obtained in a solar physics course for high school students promoted at the Dietrich Schiel Observatory of the University of São Paulo (USP). The course was elaborated by the authors with the intention of investigating student's concepts about the Sun, teaching topics of modern physics related to the Sun and providing students with knowledge about our star as well. The methodology of data gathering consisted of audio and video records of classes and of semi-structured interviews, and analysis of answers to written questionnaires. The results showed that most high school students conceived the Sun as made of fire, while sunspots were thought to be holes in the Sun. Even though some students did know that a spectrum is formed using a prism or diffraction grating, most of them ignored the nature of the observed spectral lines. Through the course, this topic was developed by means of a practical approach with solar and lamp spectra observations. The results obtained in the course point to the importance of science centers as partners in formal education. In this specific case, the Solar Room at the Dietrich Schiel Observatory is as a favorable environment for teaching modern physics in high school. Este artículo analiza los resultados obtenidos en un curso sobre la física solar, auspiciado por el Observatorio Dietrich Schiel de la USP para estudiantes de las escuelas secundarias. El curso fue diseñado por los autores con la intención de investigar las concepciones sobre el sol, enseñar temas relacionados con la física moderna del Sol y conocimientos generales sobre el astro rey. La metodología utilizada para la recolección de datos consistió en grabar, en audio y video, las clases, las entrevistas semi-estructuradas y las respuestas a los cuestionarios escritos. Los resultados mostraron que la mayoría de los participantes conciben el Sol como constituido por fuego y las manchas solares en la superficie solar como agujeros. Aunque

  12. A dynamic system to forecast ionospheric storm disturbances based on solar wind conditions

    Directory of Open Access Journals (Sweden)

    L. R. Cander

    2005-06-01

    Full Text Available For the reliable performance of technologically advanced radio communications systems under geomagnetically disturbed conditions, the forecast and modelling of the ionospheric response during storms is a high priority. The ionospheric storm forecasting models that are currently in operation have shown a high degree of reliability during quiet conditions, but they have proved inadequate during storm events. To improve their prediction accuracy, we have to take advantage of the deeper understanding in ionospheric storm dynamics that is currently available, indicating a correlation between the Interplanetary Magnetic Field (IMF disturbances and the qualitative signature of ionospheric storm disturbances at middle latitude stations. In this paper we analyse observations of the foF2 critical frequency parameter from one mid-latitude European ionospheric station (Chilton in conjunction with observations of IMF parameters (total magnitude, Bt and Bz-IMF component from the ACE spacecraft mission for eight storm events. The determination of the time delay in the ionospheric response to the interplanetary medium disturbances leads to significant results concerning the forecast of the ionospheric storms onset and their development during the first 24 h. In this way the real-time ACE observations of the solar wind parameters may be used in the development of a real-time dynamic ionospheric storm model with adequate accuracy.

  13. Bi facial silicon solar cell study in modelling in frequency dynamic regime under multispectral illumination: Recombination parameters determination methods

    International Nuclear Information System (INIS)

    ZERBO Issa

    2010-01-01

    A bibliographic study on the techniques of characterization of silicon solar cell, diodes, massifs and silicon wafer are presented. The influence of the modulation frequency and recombination in volume and in surface phenomena of on the profiles of carriers' densities, photocurrent and photovoltage has been put in evidence. The study of surface recombination velocities permitted to show that the bi facial silicon solar cell of Back Surface Field type behaves like an ohmic contacts solar cell for modulation frequencies above 40 khz. pplicability in frequency dynamic regime in the frequency range [0 - 40 khz] of three techniques of steady state recombination parameters determination is shown. A technique of diffusion length determination, in the range of (200 Hz - 40 khz] is proposed. It rests on the measurement of the short circuit current phase that is compared with the theoretical curve of short circuit current phase. The intersection of the experimental short circuit current phase and the theoretical curve of short circuit current phase permits to get the minority carriers effective diffusion length. An equivalent electric model of a solar cell in frequency dynamic regime is proposed. A study in modelling of the bi facial solar cell shunt resistance and space charge zone capacity is led from a determination method of these parameters proposed in steady state. (Author [fr

  14. Solar Imagery - Chromosphere - H-Alpha

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of H-alpha photographic datasets contributed by a number of national and private solar observatories located worldwide. Solar...

  15. Quantifying Spatiotemporal Dynamics of Solar Radiation over the Northeast China Based on ACO-BPNN Model and Intensity Analysis

    Directory of Open Access Journals (Sweden)

    Xiangqian Li

    2017-01-01

    Full Text Available Reliable information on the spatiotemporal dynamics of solar radiation plays a crucial role in studies relating to global climate change. In this study, a new backpropagation neural network (BPNN model optimized with an Ant Colony Optimization (ACO algorithm was developed to generate the ACO-BPNN model, which had demonstrated superior performance for simulating solar radiation compared to traditional BPNN modelling, for Northeast China. On this basis, we applied an intensity analysis to investigate the spatiotemporal variation of solar radiation from 1982 to 2010 over the study region at three levels: interval, category, and conversion. Research findings revealed that (1 the solar radiation resource in the study region increased from the 1980s to the 2000s and the average annual rate of variation from the 1980s to the 1990s was lower than that from the 1990s to the 2000s and (2 the gains and losses of solar radiation at each level were in different conditions. The poor, normal, and comparatively abundant levels were transferred to higher levels, whereas the abundant level was transferred to lower levels. We believe our findings contribute to implementing ad hoc energy management strategies to optimize the use of solar radiation resources and provide scientific suggestions for policy planning.

  16. The SOAR Telescope Project Southern Observatory for Astronomical Research (SOAR)

    Science.gov (United States)

    2003-03-21

    completed SOAR dome and facility. 2. Dome The preliminary design of the dome was handled by M3 (US). A Brazilian firm, Equatorial Sistemas led the...for the Gemini Telescope during construction, now Project Manager at the National Solar Observatory • Robert Shelton, Provost of the University on

  17. Current Status of Carl Sagan Observatory in Mexico

    Science.gov (United States)

    Sanchez-Ibarra, A.

    The current status of Observatory "Carl Sagan" (OCS) of University of Sonora is presented. This project was born in 1996 focused to build a small solar-stellar observatory completely operated by remote control. The observatory will be at "Cerro Azul", a 2480 m peak in one of the best regions in the world for astronomical observation, at the Sonora-Arizona desert. The OCS, with three 16 cm solar telescopes and a 55 cm stellar telescope is one of the cheapest observatories, valuated in US200,000 Added to its scientific goals to study solar coronal holes and Supernovae Type 1A, the OCS has a strong educative and cultural program in Astronomy to all levels. At the end of 2001, we started the Program "Constelacion", to build small planetariums through all the countries with a cost of only US80,000. Also, the webcast system for transmission of the solar observations from the prototype OCS at the campus, was expanded to webcast educational programs in Astronomy since July of this year, including courses and diplomats for Latin American people. All of these advances are exposed here.

  18. Conceptual design of the International Axion Observatory (IAXO)

    DEFF Research Database (Denmark)

    Armengaud, E.; Avignone, F. T.; Betz, M.

    2014-01-01

    The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO wi...

  19. A New Observatory for Eastern College: A Dream Realized

    Science.gov (United States)

    Bradstreet, D. H.

    1996-12-01

    The Eastern College Observatory began as a rooftop observing deck with one Celestron 8 telescope in 1976 as the workhorse instrument of the observational astronomy lab within the core curriculum. For 20 years the observing deck served as the crude observatory, being augmented through the years by other computerized Celestron 8's and a 17.5" diameter Dobsonian with computerized setting circles. The lab consisted primarily of visual observations and astrophotography. In 1987 plans were set into motion to raise money to build a permanent Observatory on the roof of the main classroom building. Fundraising efforts included three Jog-A-Thons (raising more than $40,000) and many donations from individuals and foundations. The fundraising was completed in 1996 and a two telescope observatory was constructed in the summer of 1996 complete with warm room, CCD cameras, computers, spectrograph, video network, and computerized single channel photometer. The telescopes are computerized 16" diameter Meade LX200 Schmidt-Cassegrains, each coupled to Gateway Pentium Pro 200 MHz computers. SBIG ST-8 CCD cameras were also secured for each telescope and an Optec SSP-7 photometer and Optomechanics Research 10C Spectrograph were also purchased. A Daystar H-alpha solar filter and Thousand Oaks visual light solar filter have expanded the Observatory's functionality to daytime observing as well. This is especially useful for the thousands of school children who frequent the Planetarium each year. The Observatory primarily serves the core astronomy lab where students must observe and photograph a prescribed number of celestial objects in a semester. Advanced students can take directed studies where they conduct photometry on eclipsing binaries or other variable stars or search for new asteroids. In addition, the Observatory and Planetarium are open to the public. Interested members of the community can reserve time on the telescopes and receive training and supervision from lab assistants

  20. A novel solar-assisted heat pump driven by photovoltaic/thermal collectors: Dynamic simulation and thermoeconomic optimization

    International Nuclear Information System (INIS)

    Calise, Francesco; Dentice d'Accadia, Massimo; Figaj, Rafal Damian; Vanoli, Laura

    2016-01-01

    This paper presents a dynamic simulation model and a thermo-economic analysis of a novel polygeneration system based on a solar-assisted heat pump and an adsorption chiller, both driven by PVT (photovoltaic/thermal) collectors. The aim of this work is to design and dynamically simulate a novel ultra-high efficient solar heating and cooling system. The overall plant layout is designed to supply electricity, space heating and cooling and domestic hot water for a small residential building. The system combines solar cooling, solar-assisted heat pump and photovoltaic/thermal collector technologies in a novel solar polygeneration system. In fact, the polygeneration system is based on a PVT solar field, coupled with a water-to-water electric heat pump or to an adsorption chiller. PVT collectors simultaneously produce electricity and thermal energy. During the winter, hot water produced by PVT collectors primarily supplies the evaporator of the heat pump, whereas in summer, solar energy supplies an adsorption chiller providing the required space cooling. All year long, solar thermal energy in excess is converted into DHW (domestic hot water). The system model was developed in TRNSYS environment. 1-year dynamic simulations are performed for different case studies in various weather conditions. The results are analysed on different time bases presenting energetic, environmental and economic performance data. Finally, a sensitivity analysis and a thermoeconomic optimization were performed, in order to determine the set of system design/control parameters that minimize the simple pay-back period. The results showed a total energy efficiency of the PVT of 49%, a heat pump yearly coefficient of performance for heating mode above 4 and a coefficient of performance of the adsorption chiller of 0.55. Finally, it is also concluded that system performance is highly sensitive to the PVT field area. The system is profitable when a capital investment subsidy of 50% is considered

  1. Electron-Ion Dynamics with Time-Dependent Density Functional Theory: Towards Predictive Solar Cell Modeling: Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Maitra, Neepa [Hunter College City University of New York, New York, NY (United States)

    2016-07-14

    This project investigates the accuracy of currently-used functionals in time-dependent density functional theory, which is today routinely used to predict and design materials and computationally model processes in solar energy conversion. The rigorously-based electron-ion dynamics method developed here sheds light on traditional methods and overcomes challenges those methods have. The fundamental research undertaken here is important for building reliable and practical methods for materials discovery. The ultimate goal is to use these tools for the computational design of new materials for solar cell devices of high efficiency.

  2. Evolution and dynamics of orphan penumbrae in the solar photosphere: Analysis from multi-instrument observations

    International Nuclear Information System (INIS)

    Zuccarello, Francesca; Guglielmino, Salvo L.; Romano, Paolo

    2014-01-01

    We investigate the dynamics and magnetic properties of orphan penumbrae observed in the solar photosphere to understand the formation process of such structures. We observed two orphan penumbrae in active region NOAA 11089 during a coordinated observing campaign carried out in 2010 July, involving the Hinode/Solar Optical Telescope (SOT) and Dutch Open Telescope (DOT), benefiting also from continuous observations acquired by the SDO satellite. We follow their evolution during about three days. The two structures form in different ways: one seems to break off the penumbra of a nearby sunspot, the other is formed through the emergence of new flux. Then they fragment while evolving. The SDO Helioseismic and Magnetic Imager measurements indicate the presence of strong line-of-sight motions in the regions occupied by these orphan penumbrae, lasting for several hours and decreasing with time. This is confirmed by SOT spectro-polarimetric measurements of the Fe I 630.2 nm pair. The latter also show that Stokes parameters exhibit significant asymmetries in the orphan penumbral regions, typical of an uncombed filamentary structure. The orphan penumbrae lie above polarity inversion lines, where peculiar plasma motions take place with velocities larger than ±3 km s –1 . The vector magnetic field in these regions is highly inclined, with the average magnetic field strength decreasing with time. The DOT observations in the Hα line and SDO Atmospheric Imaging Assembly measurements in the He II 30.4 nm line indicate that there is no counterpart for the orphan penumbrae at midchromospheric heights or above. Our findings suggest that in at least one of the features investigated the emerging flux may be trapped in the low atmospheric layers by the overlying pre-existing fields, forming these filamentary structures.

  3. Evolution and dynamics of orphan penumbrae in the solar photosphere: Analysis from multi-instrument observations

    Energy Technology Data Exchange (ETDEWEB)

    Zuccarello, Francesca [Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Guglielmino, Salvo L.; Romano, Paolo, E-mail: fzu@oact.inaf.it [INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy)

    2014-05-20

    We investigate the dynamics and magnetic properties of orphan penumbrae observed in the solar photosphere to understand the formation process of such structures. We observed two orphan penumbrae in active region NOAA 11089 during a coordinated observing campaign carried out in 2010 July, involving the Hinode/Solar Optical Telescope (SOT) and Dutch Open Telescope (DOT), benefiting also from continuous observations acquired by the SDO satellite. We follow their evolution during about three days. The two structures form in different ways: one seems to break off the penumbra of a nearby sunspot, the other is formed through the emergence of new flux. Then they fragment while evolving. The SDO Helioseismic and Magnetic Imager measurements indicate the presence of strong line-of-sight motions in the regions occupied by these orphan penumbrae, lasting for several hours and decreasing with time. This is confirmed by SOT spectro-polarimetric measurements of the Fe I 630.2 nm pair. The latter also show that Stokes parameters exhibit significant asymmetries in the orphan penumbral regions, typical of an uncombed filamentary structure. The orphan penumbrae lie above polarity inversion lines, where peculiar plasma motions take place with velocities larger than ±3 km s{sup –1}. The vector magnetic field in these regions is highly inclined, with the average magnetic field strength decreasing with time. The DOT observations in the Hα line and SDO Atmospheric Imaging Assembly measurements in the He II 30.4 nm line indicate that there is no counterpart for the orphan penumbrae at midchromospheric heights or above. Our findings suggest that in at least one of the features investigated the emerging flux may be trapped in the low atmospheric layers by the overlying pre-existing fields, forming these filamentary structures.

  4. Evolution and Dynamics of Orphan Penumbrae in the Solar Photosphere: Analysis from Multi-instrument Observations

    Science.gov (United States)

    Zuccarello, Francesca; Guglielmino, Salvo L.; Romano, Paolo

    2014-05-01

    We investigate the dynamics and magnetic properties of orphan penumbrae observed in the solar photosphere to understand the formation process of such structures. We observed two orphan penumbrae in active region NOAA 11089 during a coordinated observing campaign carried out in 2010 July, involving the Hinode/Solar Optical Telescope (SOT) and Dutch Open Telescope (DOT), benefiting also from continuous observations acquired by the SDO satellite. We follow their evolution during about three days. The two structures form in different ways: one seems to break off the penumbra of a nearby sunspot, the other is formed through the emergence of new flux. Then they fragment while evolving. The SDO Helioseismic and Magnetic Imager measurements indicate the presence of strong line-of-sight motions in the regions occupied by these orphan penumbrae, lasting for several hours and decreasing with time. This is confirmed by SOT spectro-polarimetric measurements of the Fe I 630.2 nm pair. The latter also show that Stokes parameters exhibit significant asymmetries in the orphan penumbral regions, typical of an uncombed filamentary structure. The orphan penumbrae lie above polarity inversion lines, where peculiar plasma motions take place with velocities larger than ±3 km s-1. The vector magnetic field in these regions is highly inclined, with the average magnetic field strength decreasing with time. The DOT observations in the Hα line and SDO Atmospheric Imaging Assembly measurements in the He II 30.4 nm line indicate that there is no counterpart for the orphan penumbrae at midchromospheric heights or above. Our findings suggest that in at least one of the features investigated the emerging flux may be trapped in the low atmospheric layers by the overlying pre-existing fields, forming these filamentary structures.

  5. Probing the Solar Interior

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 3. Probing the Solar Interior Hearing the Heartbeats of the Sun. Ashok Ambastha. General ... Author Affiliations. Ashok Ambastha1. Joint In-Charge Udaipur Solar Observatory Physical Research laboratory P.O. Box No. 198 Udaipur 313 001, India ...

  6. Astronomical publications of Melbourne Observatory

    Science.gov (United States)

    Andropoulos, Jenny Ioanna

    2014-05-01

    During the second half of the 19th century and the first half of the 20th century, four well-equipped government observatories were maintained in Australia - in Melbourne, Sydney, Adelaide and Perth. These institutions conducted astronomical observations, often in the course of providing a local time service, and they also collected and collated meteorological data. As well, some of these observatories were involved at times in geodetic surveying, geomagnetic recording, gravity measurements, seismology, tide recording and physical standards, so the term "observatory" was being used in a rather broad sense! Despite the international renown that once applied to Williamstown and Melbourne Observatories, relatively little has been written by modern-day scholars about astronomical activities at these observatories. This research is intended to rectify this situation to some extent by gathering, cataloguing and analysing the published astronomical output of the two Observatories to see what contributions they made to science and society. It also compares their contributions with those of Sydney, Adelaide and Perth Observatories. Overall, Williamstown and Melbourne Observatories produced a prodigious amount of material on astronomy in scientific and technical journals, in reports and in newspapers. The other observatories more or less did likewise, so no observatory of those studied markedly outperformed the others in the long term, especially when account is taken of their relative resourcing in staff and equipment.

  7. Sudbury neutrino observatory

    International Nuclear Information System (INIS)

    Ewan, G.T.; Mak, H.B.; Robertson, B.C.

    1985-07-01

    This report discusses the proposal to construct a unique neutrino observatory. The observatory would contain a Cerenkov detector which would be located 2070 m below the earth's surface in an INCO mine at Creighton near Sudbury and would contain 1000 tons of D20 which is an excellent target material. Neutrinos carry detailed information in their spectra on the reactions taking place deep in the interstellar interior and also provide information on supernova explosions. In addition to their role as astrophysical probes a knowledge of the properties of neutrinos is crucial to theories of grand unification. There are three main objectives of the laboratory. The prime objective will be to study B electron neutrinos from the sun by a direct counting method that will measure their energy and direction. The second major objective will be to establish if electron neutrinos change into other neutrino species in transit from the sun to the earth. Finally it is hoped to be able to observe a supernova with the proposed detector. The features of the Sudbury Neutrino Observatory which make it unique are its high sensitivity to electron neutrinos and its ability to detect all other types of neutrinos of energy greater than 2.2 MeV. In section II of this proposal the major physics objectives are discussed in greater detail. A conceptual design for the detector, and measurements and calculations which establish the feasibility of the neutrino experiments are presented in section III. Section IV is comprised of a discussion on the possible location of the laboratory and Section V contains a brief indication of the main areas to be studied in Phase II of the design study

  8. Sudbury neutrino observatory

    International Nuclear Information System (INIS)

    Ewan, G.T.; Evans, H.C.; Lee, H.W.

    1986-10-01

    This report is a supplement to a report (SNO-85-3 (Sudbury Neutrino Observatory)) which contained the results of a feasibility study on the construction of a deep underground neutrino observatory based on a 1000 ton heavy water Cerenkov detector. Neutrinos carry detailed information in their spectra on the reactions taking place deep in the interstellar interior and also provide information on supernova explosions. In addition to their role as astrophysical probes, a knowledge of the properties of neutrinos is crucial to theories of grand unification. The Sudbury Neutrino Observatory is unique in its high sensitivity to electron neutrinos and its ability to detect all other types of neutrinos of energy greater than 2.2 MeV. The results of the July 1985 study indicated that the project is technically feasible in that the proposed detector can measure the direction and energy of electron neutrinos above 7 MeV and the scientific programs will make significant contributions to physics and astrophysics. This present report contains new information obtained since the 1985 feasibility study. The enhanced conversion of neutrinos in the sun and the new physics that could be learned using the heavy water detector are discussed in the physics section. The other sections will discuss progress in the areas of practical importance in achieving the physics objectives such as new techniques to measure, monitor and remove low levels of radioactivity in detector components, ideas on calibration of the detector and so forth. The section entitled Administration contains a membership list of the working groups within the SNO collaboration

  9. The Observatory Health Report

    Directory of Open Access Journals (Sweden)

    Laura Murianni

    2008-06-01

    Full Text Available

    Background: The number of indicators aiming to provide a clear picture of healthcare needs and the quality and efficiency of healthcare systems and services has proliferated in recent years. The activity of the National Observatory on Health Status in the Italian Regions is multidisciplinary, involving around 280 public health care experts, clinicians, demographers, epidemiologists, mathematicians, statisticians and economists who with their different competencies, and scientific interests aim to improve the collective health of individuals and their conditions through the use of “core indicators”. The main outcome of the National Observatory on Health Status in the Italian Regions is the “Osservasalute Report – a report on health status and the quality of healthcare assistance in the Italian Regions”.

    Methods: The Report adopts a comparative analysis, methodology and internationally validated indicators.

    Results: The results of Observatory Report show it is necessary:

    • to improve the monitoring of primary health care services (where the chronic disease could be cared through implementation of clinical path;

     • to improve in certain areas of hospital care such as caesarean deliveries, as well as the average length of stay in the pre-intervention phase, etc.;

    • to try to be more focused on the patients/citizens in our health care services; • to practice more geographical interventions to reduce the North-South divide as well as reduce gender inequity.

    Conclusions: The health status of Italian people is good with positive results and outcomes, but in the meantime some further efforts should be done especially in the South that still has to improve the quality and the organization of health care services. There are huge differences in accuracy and therefore usefulness of the reported data, both between diseases and between

  10. High temperature solar heating and cooling systems for different Mediterranean climates: Dynamic simulation and economic assessment

    International Nuclear Information System (INIS)

    Calise, Francesco

    2012-01-01

    The paper presents a dynamic model of an innovative solar heating and cooling system (SHC) based on the coupling of Parabolic Trough Collectors (PTC) with a double-stage LiBr-H 2 O absorption chiller; auxiliary energy for both heating and cooling is supplied by a biomass-fired heater. The system layout also includes a number of additional components such as: cooling tower, pumps, heat exchangers, etc. The consumption of non-renewable energy resources is only due to the small amount of electrical energy consumed by some auxiliary device. A case study is presented, in which the SHC provides space heating and cooling and domestic hot water for a small university hall, all year long. Both the SHC system and the building were dynamically simulated in TRNSYS. In order to evaluate the performance of the investigated system in various climatic conditions, the analyses were performed for seven Mediterranean cities in Italy, Spain, Egypt, France, Greece and Turkey. The analysis was also performed for a similar SHC in which the biomass heater was replaced by a gas-fired heater, in order to evaluate the influence of biomass to the overall system economic and energetic performance. In addition, a parametric analysis was performed in order to evaluate the sensitivity of the results, when varying some of the main design and operating parameters, such as: collector field area, tank volume and set-point temperatures. The results showed that the SHC system layout investigated can be competitive for the majority of the locations analysed, although the economic profitability is higher for the hottest climates. - Highlights: → In the high temperature SHC system the auxiliary heat is provided by biomass. → The energetic performance of the system is excellent during the summer. → In the winter the system suffers of the low beam radiation incident on the PTC. → The Simple Pay Back Period is encouraging, particularly in case of public funding. → An increase of the solar field

  11. Comparison of ionospheric convection and the transpolar potential before and after solar wind dynamic pressure fronts: implications for magnetospheric reconnection

    Science.gov (United States)

    Boudouridis, A.; Zesta, E.; Lyons, L. R.; Kim, H.-J.; Lummerzheim, D.; Wiltberger, M.; Weygand, J. M.; Ruohoniemi, J. M.; Ridley, A. J.

    2012-04-01

    The solar wind dynamic pressure, both through its steady state value and through its variations, plays an important role in the determination of the state of the terrestrial magnetosphere and ionosphere, its effects being only secondary to those of the Interplanetary Magnetic Field (IMF). Recent studies have demonstrated the significant effect solar wind dynamic pressure enhancements have on ionospheric convection and the transpolar potential. Further studies have shown a strong response of the polar cap boundary and thus the open flux content of the magnetosphere. These studies clearly illustrate the strong coupling of solar wind dynamic pressure fronts to the terrestrial magnetosphere-ionosphere system. We present statistical studies of the response of Super Dual Auroral Radar Network (SuperDARN) flows, and Assimilative Mapping of Ionospheric Electrodynamics (AMIE) transpolar potentials to sudden enhancements in solar wind dynamic pressure. The SuperDARN results show that the convection is enhanced within both the dayside and nightside ionosphere. The dayside response is more clear and immediate, while the response on the nightside is slower and more evident for low IMF By values. AMIE results show that the overall convection, represented by the transpolar potential, has a strong response immediately after an increase in pressure, with magnitude and duration modulated by the background IMF Bz conditions. We compare the location of the SuperDARN convection enhancements with the location and motion of the polar cap boundary, as determined by POLAR Ultra-Violet Imager (UVI) images and runs of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic model for specific events. We find that the boundary exhibits a poleward motion after the increase in dynamic pressure. The enhanced ionospheric flows and the poleward motion of the boundary on the nightside are both signatures of enhanced tail reconnection, a conclusion that is reinforced by the observation of the

  12. The Lowell Observatory Predoctoral Fellowship Program

    Science.gov (United States)

    Prato, Lisa A.; Shkolnik, E.

    2014-01-01

    Lowell Observatory is pleased to solicit applications for our Predoctoral Fellowship Program. Now beginning its seventh year, this program is designed to provide unique research opportunities to graduate students in good standing, currently enrolled at Ph.D. granting institutions. Lowell staff research spans a wide range of topics, from astronomical instrumentation, to icy bodies in our solar system, exoplanet science, stellar populations, star formation, and dwarf galaxies. The Observatory's new 4.3 meter Discovery Channel Telescope has successfully begun science operations and we anticipate the commissioning of several new instruments in 2014, making this a particularly exciting time to do research at Lowell. Student research is expected to lead to a thesis dissertation appropriate for graduation at the doctoral level at the student's home institution. The Observatory provides competitive compensation and full benefits to student scholars. For more information, see http://www2.lowell.edu/rsch/predoc.php and links therein. Applications for Fall 2014 are due by May 1, 2014.

  13. Recent results from the Compton Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Michelson, P.F.; Hansen, W.W. [Stanford Univ., CA (United States)

    1994-12-01

    The Compton Observatory is an orbiting astronomical observatory for gamma-ray astronomy that covers the energy range from about 30 keV to 30 GeV. The Energetic Gamma Ray Experiment Telescope (EGRET), one of four instruments on-board, is capable of detecting and imaging gamma radiation from cosmic sources in the energy range from approximately 20 MeV to 30 GeV. After about one month of tests and calibration following the April 1991 launch, a 15-month all sky survey was begun. This survey is now complete and the Compton Observatory is well into Phase II of its observing program which includes guest investigator observations. Among the highlights from the all-sky survey discussed in this presentation are the following: detection of five pulsars with emission above 100 MeV; detection of more than 24 active galaxies, the most distant at redshift greater than two; detection of many high latitude, unidentified gamma-ray sources, some showing significant time variability; detection of at least two high energy gamma-ray bursts, with emission in one case extending to at least 1 GeV. EGRET has also detected gamma-ray emission from solar flares up to energies of at least 2 GeV and has observed gamma-rays from the Large Magellanic Cloud.

  14. Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Man [Seoul Nat' l Univ., Seoul (Korea, Republic of); Zhong, Yiming; Nam, Jin Hyun [Daegu Univ., Daegu (Korea, Republic of); Chung, Jae Dong [Sejong Univ., Seoul (Korea, Republic of); Hong, Hiki [Kyung Hee Univ., Seoul (Korea, Republic of)

    2013-04-15

    In a solar domestic hot water (Shadow) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (Test) as hot water. In this study, a computational fluid dynamics (CAD) model was developed to predict the solar thermal energy storage in a hybrid type Test equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a Test, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the Test. The developed model was validated by the good agreement between the CAD results and the experimental results performed with the hybrid-type Test in Shadow settings.

  15. Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater

    International Nuclear Information System (INIS)

    Baek, Seung Man; Zhong, Yiming; Nam, Jin Hyun; Chung, Jae Dong; Hong, Hiki

    2013-01-01

    In a solar domestic hot water (Shadow) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (Test) as hot water. In this study, a computational fluid dynamics (CAD) model was developed to predict the solar thermal energy storage in a hybrid type Test equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a Test, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the Test. The developed model was validated by the good agreement between the CAD results and the experimental results performed with the hybrid-type Test in Shadow settings

  16. Ionospheric Caustics in Solar Radio Observations

    Science.gov (United States)

    Koval, A.; Chen, Y.; Stanislavsky, A.

    2016-12-01

    The Earth ionosphere possesses by natural focusing and defocusing effects on radio waves due to presence of variable ionospheric irregularities which could act like convergent and divergent lenses on incident radiation. In particular, the focusing of emission from the Sun was firstly detected on the Nançay Decameter Array dynamic spectra in the 1980s. On time-frequency spectrograms the intensity variations form specific structures different from well-known solar radio bursts and clearly distinguishing on a background of solar radiation. Such structures have been identified as ionospheric caustics (ICs) and considered to be the result of radio waves refraction on medium scale travelling ionospheric disturbances (MSTIDs). Although nowadays the ICs are registered by different radio observatories due to augmentation of low-frequency radio telescopes, the most recent papers devoted to ICs in solar radio records date back to the 1980s. In this study, we revisit the ICs issue with some new results by conducting a statistical analysis of occurrence rate of ICs in solar dynamic spectra in meter-decameter wavelength range for long continuous period (15 years). The seasonal variations in ICs appearance have been found for the first time. Besides, we report the possible solar cycle dependence of ICs emergence. The radio waves propagation in the ionosphere comprising MSTIDs will be considered. The present research renews the subject of ICs in the low-frequency solar radio astronomy after about 35-year letup.

  17. Analysis and validation of a quasi-dynamic model for a solar collector field with flat plate collectors and parabolic trough collectors in series for district heating

    DEFF Research Database (Denmark)

    Tian, Zhiyong; Perers, Bengt; Furbo, Simon

    2018-01-01

    performance of the hybrid solar district heating plants is also presented. The measured and simulated results show that the integration of parabolic trough collectors in solar district heating plants can guarantee that the system produces hot water with relatively constant outlet temperature. The daily energy......A quasi-dynamic TRNSYS simulation model for a solar collector field with flat plate collectors and parabolic trough collectors in series was described and validated. A simplified method was implemented in TRNSYS in order to carry out long-term energy production analyses of the whole solar heating...... plant. The advantages of the model include faster computation with fewer resources, flexibility of different collector types in solar heating plant configuration and satisfactory accuracy in both dynamic and long-term analyses. In situ measurements were taken from a pilot solar heating plant with 5960 m...

  18. Flexible dynamic operation of solar-integrated power plant with solvent based post-combustion carbon capture (PCC) process

    International Nuclear Information System (INIS)

    Qadir, Abdul; Sharma, Manish; Parvareh, Forough; Khalilpour, Rajab; Abbas, Ali

    2015-01-01

    Highlights: • Flexible operation of power and PCC plant may significantly increase operational revenue. • Higher optimal carbon capture rates observed with solar thermal energy input. • Solar thermal repowering of the power plant provides highest net revenue. • Constant optimal capture rate observed for one of the flexible operation cases. • Up to 42% higher revenue generation observed between two cases with solar input. - Abstract: This paper examines flexible operation of solvent-based post-combustion carbon capture (PCC) for the reduction of power plant carbon emissions while minimizing revenue loss due to the reduced power plant electricity output. The study is conducted using a model superstructure enveloping three plants; a power plant, a PCC plant and a solar thermal field where the power plant and PCC plant are operated flexibly under the influence of hourly electricity market and weather conditions. Reduced (surrogate) models for the reboiler duty and auxiliary power requirement for the carbon capture plant are generated and applied to simulate and compare four cases, (A) power plant with PCC, (B) power plant with solar assisted PCC, (C) power plant with PCC and solar repowering – variable net electricity output and (D) power plant with PCC and solar repowering – fixed net electricity output. Such analyses are conducted under dynamic conditions including power plant part-load operation while varying the capture rate to optimize the revenue of the power plant. Each case was simulated with a lower carbon price of $25/tonne-CO 2 and a higher price of $50/tonne-CO 2 . The comparison of cases B–D found that optimal revenue generation for case C can be up to 42% higher than that of solar-assisted PCC (case B). Case C is found to be the most profitable with the lowest carbon emissions intensity and is found to exhibit a constant capture rate for both carbon prices. The optimal revenue for case D is slightly lower than case C for the lower carbon

  19. Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

    Science.gov (United States)

    Ozturk, D. S.; Zou, S.; Ridley, A. J.; Slavin, J. A.

    2018-04-01

    The global magnetosphere-ionosphere-thermosphere system is intrinsically coupled and susceptible to external drivers such as solar wind dynamic pressure enhancements. In order to understand the large-scale dynamic processes in the magnetosphere-ionosphere-thermosphere system due to the compression from the solar wind, the 17 March 2015 sudden commencement was studied in detail using global numerical models. This storm was one of the most geoeffective events of the solar cycle 24 with a minimum Dst of -222 nT. The Wind spacecraft recorded a 10-nPa increment in the solar wind dynamic pressure, while the interplanetary magnetic field BZ became further northward. The University of Michigan Block-Adaptive-Tree Solar wind Roe-type Upwind Scheme global magnetohydrodynamic code was utilized to study the generation and propagation of perturbations associated with the compression of the magnetosphere system. In addition, the high-resolution electric potential and auroral power output from the magnetohydrodynamic model was used to drive the global ionosphere-thermosphere model to investigate the ionosphere-thermosphere system response to pressure enhancement. During the compression, the electric potentials and convection patterns in the polar ionosphere were significantly altered when the preliminary impulse and main impulse field-aligned currents moved from dayside to nightside. As a result of enhanced frictional heating, plasma and neutral temperatures increased at the locations where the flow speeds were enhanced, whereas the electron density dropped at these locations. In particular, the region between the preliminary impulse and main impulse field-aligned currents experienced the most significant heating with 1000-K ion temperature increase and 20-K neutral temperature increase within 2 min. Comparison of the simulation results with the Poker Flat Incoherent Scatter Radar observations showed reasonable agreements despite underestimated magnitudes.

  20. Statistical Studies of Solar White-light Flares and Comparisons with Superflares on Solar-type Stars

    Science.gov (United States)

    Namekata, Kosuke; Sakaue, Takahito; Watanabe, Kyoko; Asai, Ayumi; Maehara, Hiroyuki; Notsu, Yuta; Notsu, Shota; Honda, Satoshi; Ishii, Takako T.; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari

    2017-12-01

    Recently, many superflares on solar-type stars have been discovered as white-light flares (WLFs). The statistical study found a correlation between their energies (E) and durations (τ): τ \\propto {E}0.39, similar to those of solar hard/soft X-ray flares, τ \\propto {E}0.2{--0.33}. This indicates a universal mechanism of energy release on solar and stellar flares, i.e., magnetic reconnection. We here carried out statistical research on 50 solar WLFs observed with Solar Dynamics Observatory/HMI and examined the correlation between the energies and durations. As a result, the E–τ relation on solar WLFs (τ \\propto {E}0.38) is quite similar to that on stellar superflares (τ \\propto {E}0.39). However, the durations of stellar superflares are one order of magnitude shorter than those expected from solar WLFs. We present the following two interpretations for the discrepancy: (1) in solar flares, the cooling timescale of WLFs may be longer than the reconnection one, and the decay time of solar WLFs can be elongated by the cooling effect; (2) the distribution can be understood by applying a scaling law (τ \\propto {E}1/3{B}-5/3) derived from the magnetic reconnection theory. In the latter case, the observed superflares are expected to have 2–4 times stronger magnetic field strength than solar flares.

  1. Dynamic Spectral Imaging of Decimetric Fiber Bursts in an Eruptive Solar Flare

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhitao; Chen, Bin; Gary, Dale E., E-mail: zw56@njit.edu [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, University Heights, Newark, NJ 07102 (United States)

    2017-10-20

    Fiber bursts are a type of fine structure that is often superposed on type IV radio continuum emission during solar flares. Although studied for many decades, its physical exciter, emission mechanism, and association with the flare energy release remain unclear, partly due to the lack of simultaneous imaging observations. We report the first dynamic spectroscopic imaging observations of decimetric fiber bursts, which occurred during the rise phase of a long-duration eruptive flare on 2012 March 3, as obtained by the Karl G. Jansky Very Large Array in 1–2 GHz. Our results show that the fiber sources are located near and above one footpoint of the flare loops. The fiber source and the background continuum source are found to be co-spatial and share the same morphology. It is likely that they are associated with nonthermal electrons trapped in the converging magnetic fields near the footpoint, as supported by a persistent coronal hard X-ray source present during the flare rise phase. We analyze three groups of fiber bursts in detail with dynamic imaging spectroscopy and obtain their mean frequency-dependent centroid trajectories in projection. By using a barometric density model and magnetic field based on a potential field extrapolation, we further reconstruct the 3D source trajectories of fiber bursts, for comparison with expectations from the whistler wave model and two MHD-based models. We conclude that the observed fiber burst properties are consistent with an exciter moving at the propagation velocity expected for whistler waves, or models that posit similar exciter velocities.

  2. Dynamic Modelling of a Solar Water Pumping System with Energy Storage

    Directory of Open Access Journals (Sweden)

    Shatadru Biswas

    2018-01-01

    Full Text Available This paper describes the dynamic modelling of a system used for extraction of groundwater for irrigation using an alternative source of energy. The system is designed based on data of an existing project in Lalmonirhat, Bangladesh. The system comprises a 38.4 kWp solar photovoltaic array, inverter, AC motor, and pump set, which can discharge a maximum of 1,930 m3 of water per day. MATLAB simulation is performed with two types of energy storage system: (i electric energy using a battery bank and (ii stored water in a large water tank. A large battery bank and a transformer are needed in the former one, which turns out as a costly solution. The latter one requires a boost converter and a large water tank to store around 2,000 m3 of water, which is also a costly solution. A combination of both systems yields an efficient and economical solution. The effectiveness of these three systems is compared with conventional diesel engine system.

  3. Multiscale Computational Fluid Dynamics: Methodology and Application to PECVD of Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Marquis Crose

    2017-02-01

    Full Text Available This work focuses on the development of a multiscale computational fluid dynamics (CFD simulation framework with application to plasma-enhanced chemical vapor deposition of thin film solar cells. A macroscopic, CFD model is proposed which is capable of accurately reproducing plasma chemistry and transport phenomena within a 2D axisymmetric reactor geometry. Additionally, the complex interactions that take place on the surface of a-Si:H thin films are coupled with the CFD simulation using a novel kinetic Monte Carlo scheme which describes the thin film growth, leading to a multiscale CFD model. Due to the significant computational challenges imposed by this multiscale CFD model, a parallel computation strategy is presented which allows for reduced processing time via the discretization of both the gas-phase mesh and microscopic thin film growth processes. Finally, the multiscale CFD model has been applied to the PECVD process at industrially relevant operating conditions revealing non-uniformities greater than 20% in the growth rate of amorphous silicon films across the radius of the wafer.

  4. Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

    Science.gov (United States)

    Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

    1987-01-01

    Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

  5. Dynamic modeling of a solar ORC with compound parabolic collectors: Annual production and comparison with steady-state simulation

    International Nuclear Information System (INIS)

    Baccioli, A.; Antonelli, M.; Desideri, U.

    2017-01-01

    Highlights: • A small scale solar ORC was investigated during a year-long simulation. • The system was operated without a thermal storage. • High flexibility thanks to a sliding-velocity control and volumetric expander. • Influence of ORC and solar field parameters considered. • Strong influence of concentration factor and system inertia. - Abstract: In this paper the dynamic behavior of a small low-concentration solar plant with static Compound Parabolic Collectors (CPC) and an ORC power unit with rotary volumetric expander has been analyzed. The plant has been simulated in transient conditions for a year-long operation and for three different sites respectively located in northern, central and southern Italy, in order to evaluate the influence of the latitude on the production. Hourly discretized data for solar radiation and for ambient temperature have been used. The adoption of a sliding-velocity control strategy, has allowed to operate without any storage system with a solar multiple (S.M.) of 1, reducing the amplitude of the solar field and simplifying the control system. Different collectors tilt angles and concentration factors, as well as thermodynamic parameters of the cycle have been tested, to evaluate the optimal working conditions for each locality. Results highlighted that specific production increased with the concentration ratio, and with the decrease of latitude. The comparison with the steady-state analysis showed that this type of control strategy is suited for those configurations having a smaller number of collectors, since the thermal inertia of the solar field is not recovered at all during the plant shut-down phase.

  6. THE EFFECT OF THE THICKNESS OF A PACKED BED ON THE DYNAMIC AND THERMAL BEHAVIOR OF A SOLAR DRYER

    Directory of Open Access Journals (Sweden)

    S KHALDI

    2015-06-01

    Full Text Available Drying food in the sun is a safe, easy and economical way to preserve food, especially fruits. Cabinet dryers are the most popular equipment for fruit drying. Because of intermittent nature of solar energy, storage is required for uninterrupted supply in order to match the needs. The main objective of this study is to assess effectiveness of continuous solar dryer integrated with packed bed as thermal storage with natural airflow for drying figs (Ficuscarica. The cabinet dryer were envisaged theoretically (computational fluid dynamics (CFD. The distribution of the velocity and temperature of air within the solar dryer were presented during one day of August and under the climate conditions of Tlemcen (Algeria.  The effects of presence of a packed bed on the distribution of velocity and temperature of airflow and on the temperature of figs were analyzed. The results show that the solar dryer design, incorporating a packed bed enhances the capabilities and performance of the solar dryer, through increasing time of drying.

  7. An Observatory to Enhance the Preparation of Future California Teachers

    Science.gov (United States)

    Connolly, L.; Lederer, S.

    2004-12-01

    With a major grant from the W. M. Keck Foundation, California State University, San Bernardino is establishing a state-of-the-art teaching astronomical observatory. The Observatory will be fundamental to an innovative undergraduate physics and astronomy curriculum for Physics and Liberal Studies majors and will be integrated into our General Education program. The critical need for a research and educational observatory is linked to changes in California's Science Competencies for teacher certification. Development of the Observatory will also complement a new infusion of NASA funding and equipment support for our growing astronomy education programs and the University's established Strategic Plan for excellence in education and teacher preparation. The Observatory will consist of two domed towers. One tower will house a 20" Ritchey-Chretien telescope equipped with a CCD camera in conjunction with either UBVRI broadband filters or a spectrometer for evening laboratories and student research projects. The second tower will house the university's existing 12" Schmidt-Cassegrain optical telescope coupled with a CCD camera and an array of filters. A small aperture solar telescope will be attached to the 12" for observing solar prominences while a milar filter can be attached to the 12" for sunspot viewing. We have been very fortunate to receive a challenge grant of \\600,000 from the W. M. Keck Foundation to equip the two domed towers; we continue to seek a further \\800,000 to meet our construction needs. Funding also provided by the California State University, San Bernardino.

  8. Experimental validation of dynamic simulation of the flat plate collector in a closed thermosyphon solar water heater

    International Nuclear Information System (INIS)

    Taherian, H.; Rezania, A.; Sadeghi, S.; Ganji, D.D.

    2011-01-01

    This work studies the dynamic simulation of thermosyphon solar water heater collector considering the weather conditions of a city in north of Iran. The simulation was done for clear and partly cloudy days. The useful energy, the efficiency diagrams, the inlet and the outlet of collector, center of the absorber and center of the glass cover temperatures, were obtained. The simulation results were then compared with the experimental results in fall and showed a good agreement.

  9. The Effects of Solar Wind Dynamic Pressure Changes on the Substorm Auroras and Energetic Electron Injections on 24 August 2005

    Science.gov (United States)

    Li, L. Y.; Wang, Z. Q.

    2018-01-01

    After the passage of an interplanetary (IP) shock at 06:13 UT on 24 August 2005, the enhancement (>6 nPa) of solar wind dynamic pressure and the southward turning of interplanetary magnetic field (IMF) cause the earthward movement of dayside magnetopause and the drift loss of energetic particles near geosynchronous orbit. The persistent electron drift loss makes the geosynchronous satellites cannot observe the substorm electron injection phenomenon during the two substorm expansion phases (06:57-07:39 UT) on that day. Behind the IP shock, the fluctuations ( 0.5-3 nPa) of solar wind dynamic pressure not only alter the dayside auroral brightness but also cause the entire auroral oval to swing in the day-night direction. However, there is no Pi2 pulsation in the nightside auroral oval during the substorm growth phase from 06:13 to 06:57 UT. During the subsequent two substorm expansion phases, the substorm expansion activities cause the nightside aurora oval brightening from substorm onset site to higher latitudes, and meanwhile, the enhancement (decline) of solar wind dynamic pressure makes the nightside auroral oval move toward the magnetic equator (the magnetic pole). These observations demonstrate that solar wind dynamic pressure changes and substorm expansion activities can jointly control the luminosity and location of the nightside auroral oval when the internal and external disturbances occur simultaneously. During the impact of a strong IP shock, the earthward movement of dayside magnetopause probably causes the disappearance of the substorm electron injections near geosynchronous orbit.

  10. Charge-Transfer Dynamics in the Lowest Excited State of a Pentacene–Fullerene Complex: Implications for Organic Solar Cells

    KAUST Repository

    Joseph, Saju

    2017-10-02

    We characterize the dynamic nature of the lowest excited state in a pentacene/C60 complex on the femtosecond time scale, via a combination of ab initio molecular dynamics and time-dependent density functional theory. We analyze the correlations between the molecular vibrations of the complex and the oscillations in the electron-transfer character of its lowest excited state, which point to vibration-induced coherences between the (pentacene-based) local-excitation (LE) state and the complex charge-transfer (CT) state. We discuss the implications of our results on this model system for the exciton-dissociation process in organic solar cells.

  11. Statistical Characteristics of Solar Wind Dynamic Pressure Enhancements During Geomagnetic Storms

    Directory of Open Access Journals (Sweden)

    C.-R. Choi

    2008-06-01

    Full Text Available Solar wind dynamic pressure enhancements are known to cause various types of disturbances to the magnetosphere. In particular, dynamic pressure enhancements may affect the evolution of magnetic storms when they occur during storm times. In this paper, we have investigated the statistical significance and features of dynamic pressure enhancements during magnetic storm times. For the investigation, we have used a total of 91 geomagnetic storms for 2001-2003, for which the Dst minimum (Dst_min is below -50 nT. Also, we have imposed a set of selection criteria for a pressure enhancement to be considered an event: The main selection criterion is that the pressure increases by ≥50% or ≥3nPa within 30 min and remains to be elevated for 10 min or longer. For our statistical analysis, we define the storm time to be the interval from the main Dst decrease, through Dst_min, to the point where the Dst index recovers by 50%. Our main results are summarized as follows. (i ~81% of the studied storms indicate at least one event of pressure enhancements. When averaged over all the 91 storms, the occurrence rate is 4.5 pressure enhancement events per storm and 0.15 pressure enhancement events per hour. (ii The occurrence rate of the pressure enhancements is about three times higher for CME-driven storm times than for CIR-driven storm times. (iii Only 21.1% of the pressure enhancements show a clear association with an interplanetary shock. (iv A large number of the pressure enhancement events are accompanied with a simultaneous change of IMF By and/or Bz: For example, 73.5% of the pressure enhancement events are associated with an IMF change of either |∆Bz|>2nT or |∆By|>2nT. This last finding suggests that one should consider possible interplay effects between the simultaneous pressure and IMF changes in many situations.

  12. Interfacial Engineering and Charge Carrier Dynamics in Extremely Thin Absorber Solar Cells

    Science.gov (United States)

    Edley, Michael

    Photovoltaic energy is a clean and renewable source of electricity; however, it faces resistance to widespread use due to cost. Nanostructuring decouples constraints related to light absorption and charge separation, potentially reducing cost by allowing a wider variety of processing techniques and materials to be used. However, the large interfacial areas also cause an increased dark current which negatively affects cell efficiency. This work focuses on extremely thin absorber (ETA) solar cells that used a ZnO nanowire array as a scaffold for an extremely thin CdSe absorber layer. Photoexcited electrons generated in the CdSe absorber are transferred to the ZnO layer, while photogenerated holes are transferred to the liquid electrolyte. The transfer of photoexcited carriers to their transport layer competes with bulk recombination in the absorber layer. After charge separation, transport of charge carriers to their respective contacts must occur faster than interfacial recombination for efficient collection. Charge separation and collection depend sensitively on the dimensions of the materials as well as their interfaces. We demonstrated that an optimal absorber thickness can balance light absorption and charge separation. By treating the ZnO/CdSe interface with a CdS buffer layer, we were able to improve the Voc and fill factor, increasing the ETA cell's efficiency from 0.53% to 1.34%, which is higher than that achievable using planar films of the same material. We have gained additional insight into designing ETA cells through the use of dynamic measurements. Ultrafast transient absorption spectroscopy revealed that characteristic times for electron injection from CdSe to ZnO are less than 1 ps. Electron injection is rapid compared to the 2 ns bulk lifetime in CdSe. Optoelectronic measurements such as transient photocurrent/photovoltage and electrochemical impedance spectroscopy were applied to study the processes of charge transport and interfacial recombination

  13. Perennial Environment Observatory

    International Nuclear Information System (INIS)

    Plas, Frederic

    2014-07-01

    The Perennial Environment Observatory [Observatoire Perenne de l'Environnement - OPE] is a unique approach and infrastructure developed and implemented by ANDRA, the French National Radioactive Waste Management Agency, as part of its overall project of deep geological disposal for radioactive waste. Its current mission is to assess the initial state of the rural (forest, pasture, open-field and aquatic) environment, prior to repository construction. This will be followed in 2017 (pending construction authorizations) and for a period exceeding a century, by monitoring of any impact the repository may have on the environment. In addition to serving its own industrial purpose of environmental monitoring, ANDRA also opens the OPE approach, infrastructure and acquired knowledge (database...) to the scientific community to support further research on long term evolution of the environment subjected to natural and anthropogenic stresses, and to contribute to a better understanding of the interaction between the various compartments of the environment

  14. Effects of a solar wind dynamic pressure increase in the magnetosphere and in the ionosphere

    Directory of Open Access Journals (Sweden)

    L. Juusola

    2010-10-01

    Full Text Available On 17 July 2005, an earthward bound north-south oriented magnetic cloud and its sheath were observed by the ACE, SoHO, and Wind solar wind monitors. A steplike increase of the solar wind dynamic pressure during northward interplanetary magnetic field conditions was related to the leading edge of the sheath. A timing analysis between the three spacecraft revealed that this front was not aligned with the GSE y-axis, but had a normal (−0.58,0.82,0. Hence, the first contact with the magnetosphere occurred on the dawnside rather than at the subsolar point. Fortunately, Cluster, Double Star 1, and Geotail happened to be distributed close to the magnetopause in this region, which made it possible to closely monitor the motion of the magnetopause. After the pressure front had impacted the magnetosphere, the magnetopause was perceived first to move inward and then immediately to correct the overshoot by slightly expanding again such that it ended up between the Cluster constellation with Double Star 1 inside the magnetosphere and Geotail in the magnetosheath. Coinciding with the inward and subsequent outward motion, the ground-based magnetic field at low latitudes was observed to first strengthen and then weaken. As the magnetopause position stabilised, so did the ground-based magnetic field intensity, settling at a level slightly higher than before the pressure increase. Altogether the magnetopause was moving for about 15 min after its first contact with the front. The high latitude ionospheric signature consisted of two parts: a shorter (few minutes and less intense preliminary part comprised a decrease of AL and a negative variation of PC. A longer (about ten minutes and more intense main part of the signature comprised an increase of AU and a positive variation of PC. Measurements from several ground-based magnetometer networks (210 MM CPMN, CANMOS, CARISMA, GIMA, IMAGE, MACCS, SuperMAG, THEMIS, TGO were used to obtain information on the

  15. The Heating of the Solar Atmosphere: from the Bottom Up?

    Science.gov (United States)

    Winebarger, Amy

    2014-01-01

    The heating of the solar atmosphere remains a mystery. Over the past several decades, scientists have examined the observational properties of structures in the solar atmosphere, notably their temperature, density, lifetime, and geometry, to determine the location, frequency, and duration of heating. In this talk, I will review these observational results, focusing on the wealth of information stored in the light curve of structures in different spectral lines or channels available in the Solar Dynamic Observatory's Atmospheric Imaging Assembly, Hinode's X-ray Telescope and Extreme-ultraviolet Imaging Spectrometer, and the Interface Region Imaging Spectrograph. I will discuss some recent results from combined data sets that support the heating of the solar atmosphere may be dominated by low, near-constant heating events.

  16. Solar line Lsub(α) profile and an interstellar wind dynamics

    International Nuclear Information System (INIS)

    Burgin, M.S.

    1978-01-01

    Analytical theory of interstellar hydrogen atom motion into the region of solar Lsub(α)-radiation is given. Hydrogen distribution in the Solar system is calculated with an account of the Lsub(α) solar line profile difference from a flat one. The effect of the profile form on the scattered radiation intensity is estimated. Calculation errors of the scattered radiation intensity, connected with the difference between a line profile and a flat one, do not exceed 5% for the real Lsub(α) solar line profile

  17. Interoperability of Heliophysics Virtual Observatories

    Science.gov (United States)

    Thieman, J.; Roberts, A.; King, T.; King, J.; Harvey, C.

    2008-01-01

    If you'd like to find interrelated heliophysics (also known as space and solar physics) data for a research project that spans, for example, magnetic field data and charged particle data from multiple satellites located near a given place and at approximately the same time, how easy is this to do? There are probably hundreds of data sets scattered in archives around the world that might be relevant. Is there an optimal way to search these archives and find what you want? There are a number of virtual observatories (VOs) now in existence that maintain knowledge of the data available in subdisciplines of heliophysics. The data may be widely scattered among various data centers, but the VOs have knowledge of what is available and how to get to it. The problem is that research projects might require data from a number of subdisciplines. Is there a way to search multiple VOs at once and obtain what is needed quickly? To do this requires a common way of describing the data such that a search using a common term will find all data that relate to the common term. This common language is contained within a data model developed for all of heliophysics and known as the SPASE (Space Physics Archive Search and Extract) Data Model. NASA has funded the main part of the development of SPASE but other groups have put resources into it as well. How well is this working? We will review the use of SPASE and how well the goal of locating and retrieving data within the heliophysics community is being achieved. Can the VOs truly be made interoperable despite being developed by so many diverse groups?

  18. Electricity and gas market observatory. 2. Quarter 2007

    International Nuclear Information System (INIS)

    2007-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). The present observatory is dedicated only to eligible customers before 1 July 2007, i.e. non-residential customers. Statistics related to residential customers will be published in the next observatory (1 December 2007). Content: A - The electricity market: The retail electricity market (Introduction, Non-residential customer segments and their respective weights, Status at July 1, 2007, Dynamic analysis: 2. Quarter 2007); The wholesale electricity market (Introduction, Wholesale market activity in France, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking fact of the second quarter 2007); B - The gas market: The retail gas market (Introduction, The non-residential customer segments and their respective weights, Status at July 1, 2007); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  19. QUIESCENT PROMINENCE DYNAMICS OBSERVED WITH THE HINODE SOLAR OPTICAL TELESCOPE. I. TURBULENT UPFLOW PLUMES

    International Nuclear Information System (INIS)

    Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

    2010-01-01

    Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) 'arches' or 'bubbles' that 'inflate' from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex 'roll-up' of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) 'optical flow' code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s -1 , which is supersonic for a ∼10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s -1 . Typical lifetimes range from 300 to 1000 s (∼5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km 2 s -1 reaching maximum projected areas from 2 to 15 Mm 2 . Maximum contrast of the dark flows relative to the bright prominence plasma in

  20. Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes

    Science.gov (United States)

    Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

    2010-06-01

    Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex "roll-up" of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) "optical flow" code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s-1, which is supersonic for a ~10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s-1. Typical lifetimes range from 300 to 1000 s (~5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km2 s-1 reaching maximum projected areas from 2 to 15 Mm2. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images

  1. Density Structures, Dynamics, and Seasonal and Solar Cycle Modulations of Saturn's Inner Plasma Disk

    Science.gov (United States)

    Holmberg, M. K. G.; Shebanits, O.; Wahlund, J.-E.; Morooka, M. W.; Vigren, E.; André, N.; Garnier, P.; Persoon, A. M.; Génot, V.; Gilbert, L. K.

    2017-12-01

    We present statistical results from the Cassini Radio and Plasma Wave Science (RPWS) Langmuir probe measurements recorded during the time interval from orbit 3 (1 February 2005) to 237 (29 June 2016). A new and improved data analysis method to obtain ion density from the Cassini LP measurements is used to study the asymmetries and modulations found in the inner plasma disk of Saturn, between 2.5 and 12 Saturn radii (1 RS=60,268 km). The structure of Saturn's plasma disk is mapped, and the plasma density peak, nmax, is shown to be located at ˜4.6 RS and not at the main neutral source region at 3.95 RS. The shift in the location of nmax is due to that the hot electron impact ionization rate peaks at ˜4.6 RS. Cassini RPWS plasma disk measurements show a solar cycle modulation. However, estimates of the change in ion density due to varying EUV flux is not large enough to describe the detected dependency, which implies that an additional mechanism, still unknown, is also affecting the plasma density in the studied region. We also present a dayside/nightside ion density asymmetry, with nightside densities up to a factor of 2 larger than on the dayside. The largest density difference is found in the radial region 4 to 5 RS. The dynamic variation in ion density increases toward Saturn, indicating an internal origin of the large density variability in the plasma disk rather than being caused by an external source origin in the outer magnetosphere.

  2. Features of energetic particle radial profiles inferred from geosynchronous responses to solar wind dynamic pressure enhancements

    Directory of Open Access Journals (Sweden)

    Y. Shi

    2009-02-01

    Full Text Available Determination of the radial profile of phase space density of relativistic electrons at constant adiabatic invariants is crucial for identifying the source for them within the outer radiation belt. The commonly used method is to convert flux observed at fixed energy to phase space density at constant first, second and third adiabatic invariants, which requires an empirical global magnetic field model and thus might produce some uncertainties in the final results. From a different perspective, in this paper we indirectly infer the shape of the radial profile of phase space density of relativistic electrons near the geosynchronous region by statistically examining the geosynchronous energetic flux response to 128 solar wind dynamic pressure enhancements during the years 2000 to 2003. We thus avoid the disadvantage of using empirical magnetic field models. Our results show that the flux response is species and energy dependent. For protons and low-energy electrons, the primary response to magnetospheric compression is an increase in flux at geosynchronous orbit. For relativistic electrons, the dominant response is a decrease in flux, which implies that the phase space density decreases toward increasing radial distance at geosynchronous orbit and leads to a local peak inside of geosynchronous orbit. The flux response of protons and non-relativistic electrons could result from a phase density that increases toward increasing radial distance, but this cannot be determined for sure due to the particle energization associated with pressure enhancements. Our results for relativistic electrons are consistent with previous results obtained using magnetic field models, thus providing additional confirmation that these results are correct and indicating that they are not the result of errors in their selected magnetic field model.

  3. THE LONG-TERM DYNAMICAL EVOLUTION OF DISK-FRAGMENTED MULTIPLE SYSTEMS IN THE SOLAR NEIGHBORHOOD

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yun [Department of Astronomy, School of Physics, Peking University, Yiheyuan Lu 5, Haidian Qu, Beijing 100871 (China); Kouwenhoven, M. B. N. [Department of Mathematical Sciences, Xi’an Jiaotong-Liverpool University, 111 Ren’ai Road, Suzhou Dushu Lake Science and Education Innovation District, Suzhou Industrial Park, Suzhou 215123 (China); Stamatellos, D. [Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Goodwin, Simon P., E-mail: t.kouwenhoven@xjtlu.edu.cn [Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2016-11-10

    The origin of very low-mass hydrogen-burning stars, brown dwarfs (BDs), and planetary-mass objects (PMOs) at the low-mass end of the initial mass function is not yet fully understood. Gravitational fragmentation of circumstellar disks provides a possible mechanism for the formation of such low-mass objects. The kinematic and binary properties of very low-mass objects formed through disk fragmentation at early times (<10 Myr) were discussed in our previous paper. In this paper we extend the analysis by following the long-term evolution of disk-fragmented systems up to an age of 10 Gyr, covering the ages of the stellar and substellar populations in the Galactic field. We find that the systems continue to decay, although the rates at which companions escape or collide with each other are substantially lower than during the first 10 Myr, and that dynamical evolution is limited beyond 1 Gyr. By t = 10 Gyr, about one third of the host stars are single, and more than half have only one companion left. Most of the other systems have two companions left that orbit their host star in widely separated orbits. A small fraction of companions have formed binaries that orbit the host star in a hierarchical triple configuration. The majority of such double-companion systems have internal orbits that are retrograde with respect to their orbits around their host stars. Our simulations allow a comparison between the predicted outcomes of disk fragmentation with the observed low-mass hydrogen-burning stars, BDs, and PMOs in the solar neighborhood. Imaging and radial velocity surveys for faint binary companions among nearby stars are necessary for verification or rejection of the formation mechanism proposed in this paper.

  4. Solar Potential Analysis and Integration of the Time-Dependent Simulation Results for Semantic 3d City Models Using Dynamizers

    Science.gov (United States)

    Chaturvedi, K.; Willenborg, B.; Sindram, M.; Kolbe, T. H.

    2017-10-01

    Semantic 3D city models play an important role in solving complex real-world problems and are being adopted by many cities around the world. A wide range of application and simulation scenarios directly benefit from the adoption of international standards such as CityGML. However, most of the simulations involve properties, whose values vary with respect to time, and the current generation semantic 3D city models do not support time-dependent properties explicitly. In this paper, the details of solar potential simulations are provided operating on the CityGML standard, assessing and estimating solar energy production for the roofs and facades of the 3D building objects in different ways. Furthermore, the paper demonstrates how the time-dependent simulation results are better-represented inline within 3D city models utilizing the so-called Dynamizer concept. This concept not only allows representing the simulation results in standardized ways, but also delivers a method to enhance static city models by such dynamic property values making the city models truly dynamic. The dynamizer concept has been implemented as an Application Domain Extension of the CityGML standard within the OGC Future City Pilot Phase 1. The results are given in this paper.

  5. Dynamic solar-powered multi-stage direct contact membrane distillation system: Concept design, modeling and simulation

    KAUST Repository

    Lee, Jung Gil

    2017-04-26

    This paper presents a theoretical analysis of the monthly average daily and hourly performances of a solar-powered multi-stage direct contact membrane distillation (SMDCMD) system with an energy recovery scheme and dynamic operating system. Mid-latitude meteorological data from Busan, Korea is employed, featuring large climate variation over the course of one year. The number of module stages used by the dynamic operating scheme changes dynamically based on the inlet feed temperature of the successive modules, which results in an improvement of the water production and thermal efficiency. The simulations of the SMDCMD system are carried out to investigate the spatial and temporal variations in the feed and permeate temperatures and permeate flux. The monthly average daily water production increases from 0.37m3/day to 0.4m3/day and thermal efficiency increases from 31% to 45% when comparing systems both without and with dynamic operation in December. The water production with respect to collector area ranged from 350m2 to 550m2 and the seawater storage tank volume ranged from 16m3 to 28.8m3, and the solar fraction at various desired feed temperatures from 50°C to 80°C have been investigated in October and December.

  6. Electricity and gas market observatory. 3. Quarter 2007

    International Nuclear Information System (INIS)

    2007-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). Since the 1 of July 2007, all customers can choose their gas and electricity suppliers. The present observatory is including residential customer's statistics. Content: A - The electricity market: The retail electricity market (Introduction, Customer segments and their respective weight, Status at September 30, 2007, Dynamic analysis: 3. Quarter 2007); The wholesale electricity market (Introduction, Wholesale market activity in France, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market); B - The gas market: The retail gas market (Introduction, Customer segments and their respective weight, Status on September 30, 2007, Dynamic analysis: 3. Quarter 2007); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  7. JHelioviewer. Time-dependent 3D visualisation of solar and heliospheric data

    Science.gov (United States)

    Müller, D.; Nicula, B.; Felix, S.; Verstringe, F.; Bourgoignie, B.; Csillaghy, A.; Berghmans, D.; Jiggens, P.; García-Ortiz, J. P.; Ireland, J.; Zahniy, S.; Fleck, B.

    2017-09-01

    Context. Solar observatories are providing the world-wide community with a wealth of data, covering wide time ranges (e.g. Solar and Heliospheric Observatory, SOHO), multiple viewpoints (Solar TErrestrial RElations Observatory, STEREO), and returning large amounts of data (Solar Dynamics Observatory, SDO). In particular, the large volume of SDO data presents challenges; the data are available only from a few repositories, and full-disk, full-cadence data for reasonable durations of scientific interest are difficult to download, due to their size and the download rates available to most users. From a scientist's perspective this poses three problems: accessing, browsing, and finding interesting data as efficiently as possible. Aims: To address these challenges, we have developed JHelioviewer, a visualisation tool for solar data based on the JPEG 2000 compression standard and part of the open source ESA/NASA Helioviewer Project. Since the first release of JHelioviewer in 2009, the scientific functionality of the software has been extended significantly, and the objective of this paper is to highlight these improvements. Methods: The JPEG 2000 standard offers useful new features that facilitate the dissemination and analysis of high-resolution image data and offers a solution to the challenge of efficiently browsing petabyte-scale image archives. The JHelioviewer software is open source, platform independent, and extendable via a plug-in architecture. Results: With JHelioviewer, users can visualise the Sun for any time period between September 1991 and today; they can perform basic image processing in real time, track features on the Sun, and interactively overlay magnetic field extrapolations. The software integrates solar event data and a timeline display. Once an interesting event has been identified, science quality data can be accessed for in-depth analysis. As a first step towards supporting science planning of the upcoming Solar Orbiter mission, JHelioviewer

  8. Response of the dynamic and thermodynamic structure of the stratosphere to the solar cycle in the boreal winter

    Science.gov (United States)

    Shi, Chunhua; Gao, Yannan; Cai, Juan; Guo, Dong; Lu, Yan

    2018-04-01

    The response of the dynamic and thermodynamic structure of the stratosphere to the solar cycle in the boreal winter is investigated based on measurements of the solar cycle by the Spectral Irradiance Monitor onboard the SORCE satellite, monthly ERA-Interim Reanalysis data from the European Center for Medium-Range Weather Forecasts, the radiative transfer scheme of the Beijing Climate Center (BCC-RAD) and a multiple linear regression model. The results show that during periods of strong solar activity, the solar shortwave heating anomaly from the climatology in the tropical upper stratosphere triggers a local warm anomaly and strong westerly winds in mid-latitudes, which strengthens the upward propagation of planetary wave 1 but prevents that of wave 2. The enhanced westerly jet makes a slight adjustment to the propagation path of wave 1, but prevents wave 2 from propagating upward, decreases the dissipation of wave 2 in the extratropical upper stratosphere and hence weakens the Brewer-Dobson circulation. The adiabatic heating term in relation to the Brewer-Dobson circulation shows anomalous warming in the tropical lower stratosphere and anomalous cooling in the mid-latitude upper stratosphere.

  9. The Importance of Marine Observatories and of RAIA in Particular

    Directory of Open Access Journals (Sweden)

    Luísa Bastos

    2016-08-01

    Full Text Available Coastal and Oceanic Observatories are important tools to provide information on ocean state, phenomena and processes. They meet the need for a better understanding of coastal and ocean dynamics, revealing regional characteristics and vulnerabilities. These observatories are extremely useful to guide human actions in response to natural events and potential climate change impacts, anticipating the occurrence of extreme weather and oceanic events and helping to minimize consequent personal and material damages and costs.International organizations and local governments have shown an increasing interest in operational oceanography and coastal, marine and oceanic observations, which resulted in substantial investments in these areas. A variety of physical, chemical and biological data have been collected to better understand the specific characteristics of each ocean area and its importance in the global context. Also the general public’s interest in marine issues and observatories has been raised, mainly in relation to vulnerability, sustainability and climate change issues. Data and products obtained by an observatory are hence useful to a broad range of stakeholders, from national and local authorities to the population in general.An introduction to Ocean Observatories, including their national and regional importance, and a brief analysis of the societal interest in these observatories and related issues are presented. The potential of a Coastal and Ocean Observatory is then demonstrated using the RAIA observatory as example. This modern and comprehensive observatory is dedicated to improve operational oceanography, technology and marine science for the North Western Iberian coast, and to provide services to a large range of stakeholders.

  10. A continued program of planetary study at the University of Texas McDonald Observatory

    Science.gov (United States)

    Trafton, L.

    1991-01-01

    The program conducts solar system research in support of NASA missions and of general astronomical interest. Investigations of composition, physical characteristics and changes in solar system bodies are conducted primarily using the facilities of McDonald Observatory. Progress, accomplishments, and projected accomplishments are discussed.

  11. Health observatories in iran.

    Science.gov (United States)

    Rashidian, A; Damari, B; Larijani, B; Vosoogh Moghadda, A; Alikhani, S; Shadpour, K; Khosravi, A

    2013-01-01

    The Islamic Republic of Iran, in her 20 year vision by the year 2025, is a developed country with the first economic, scientific and technological status in the region, with revolutionary and Islamic identity, inspiring Islamic world, as well as effective and constructive interaction in international relations. Enjoying health, welfare, food security, social security, equal opportunities, fair income distribution, strong family structure; to be away from poverty, corruption, and discrimination; and benefiting desirable living environment are also considered out of characteristics of Iranian society in that year. Strategic leadership towards perceived vision in each setting requires restrictive, complete and timely information. According to constitution of National Institute for Health Researches, law of the Fifth Development Plan of the country and characteristics of health policy making, necessity of designing a Health Observatory System (HOS) was felt. Some Principles for designing such system were formulated by taking following steps: reviewing experience in other countries, having local history of the HOS in mind, superior documents, analysis of current production and management of health information, taking the possibilities to run a HOS into account. Based on these principles, the protocol of HOS was outlined in 3 different stages of opinion poll of informed experts responsible for production on management of information, by using questionnaires and Focus Group Discussions. The protocol includes executive regulations, the list of health indicators, vocabulary and a calendar for periodic studies of the community health situation.

  12. Mobile Networked Sensors for Environmental Observatories

    Science.gov (United States)

    Kaiser, W. J.

    2005-12-01

    The development of the first embedded networked sensing (ENS) systems has been rapidly followed by their successful deployment for investigations in environments ranging from forest ecosystems, to rivers and lakes, and to subsurface soil observations. As ENS systems have been deployed, many technology challenges have been successfully addressed. For example, the requirements for local and remote data access and long operating life have been encountered and solved with a novel hierarchical network architecture and unique, low power platforms. This presentation will describe this progress and also the development and applications of a new ENS system addressing the most current challenges: A robotic ENS platform providing precise, reliable, and sustained observation capability with diverse sensing capabilities that may adapt to environmental dynamics. In the development of methods for autonomous observation by networked sensors, many applications have emerged requiring spatially and temporally intensive data sampling. Examples include the mapping of forest understory solar radiation, autonomous acquisition of imaging for plant phenology, and mapping of contaminant concentration in aquatic systems. Common to these applications is the need to actively and continuously configure the location and orientation of sensors for high fidelity mapping of the spatial distribution of phenomena. To address this primary environmental observation need, a new sensing platform, Networked Infomechanical Systems (NIMS) has been developed. NIMS relies on deployed aerial infrastructure (for example, cable suspension systems) in the natural environment to permit robotic devices to precisely and reliably move or remain stationary as required at elevations that may lie directly in or above the forest canopy or within a river or stream. NIMS systems are suspended to allow devices to translate a sensor node horizontally, and also to raise and lower devices. Examples of sensors that are now

  13. Object-oriented simulation model of a parabolic trough solar collector: Static and dynamic validation

    Science.gov (United States)

    Ubieta, Eduardo; Hoyo, Itzal del; Valenzuela, Loreto; Lopez-Martín, Rafael; Peña, Víctor de la; López, Susana

    2017-06-01

    A simulation model of a parabolic-trough solar collector developed in Modelica® language is calibrated and validated. The calibration is performed in order to approximate the behavior of the solar collector model to a real one due to the uncertainty in some of the system parameters, i.e. measured data is used during the calibration process. Afterwards, the validation of this calibrated model is done. During the validation, the results obtained from the model are compared to the ones obtained during real operation in a collector from the Plataforma Solar de Almeria (PSA).

  14. Development of an operation strategy for hydrogen production using solar PV energy based on fluid dynamic aspects

    Directory of Open Access Journals (Sweden)

    Amores Ernesto

    2017-06-01

    Full Text Available Alkaline water electrolysis powered by renewable energy sources is one of the most promising strategies for environmentally friendly hydrogen production. However, wind and solar energy sources are highly dependent on weather conditions. As a result, power fluctuations affect the electrolyzer and cause several negative effects. Considering these limiting effects which reduce the water electrolysis efficiency, a novel operation strategy is proposed in this study. It is based on pumping the electrolyte according to the current density supplied by a solar PV module, in order to achieve the suitable fluid dynamics conditions in an electrolysis cell. To this aim, a mathematical model including the influence of electrode-membrane distance, temperature and electrolyte flow rate has been developed and used as optimization tool. The obtained results confirm the convenience of the selected strategy, especially when the electrolyzer is powered by renewable energies.

  15. Transient behavior of flare-associated solar wind. II - Gas dynamics in a nonradial open field region

    Science.gov (United States)

    Nagai, F.

    1984-01-01

    Transient behavior of flare-associated solar wind in the nonradial open field region is numerically investigated, taking into account the thermal and dynamical coupling between the chromosphere and the corona. A realistic steady solar wind is constructed which passes through the inner X-type critical point in the rapidly diverging region. The wind speed shows a local maximum at the middle, O-type, critical point. The wind's density and pressure distributions decrease abruptly in the rapidly diverging region of the flow tube. The transient behavior of the wind following flare energy deposition includes ascending and descending conduction fronts. Thermal instability occurs in the lower corona, and ascending material flows out through the throat after the flare energy input ceases. A local density distribution peak is generated at the shock front due to the pressure deficit just behind the shock front.

  16. Dynamic voltage stability of a distribution system with high penetration of grid-connected photovoltaic type solar generators

    Directory of Open Access Journals (Sweden)

    Zetty Adibah Kamaruzzaman

    2016-06-01

    Full Text Available This paper presents the impact of grid-connected photovoltaic (PV generator on dynamic voltage stability of a power distribution system by considering solar intermittency, PV penetration level, and contingencies such as line outage and load increase. The IEEE 13 node test feeder is used as a test system, and a solar PV of 0.48 kV/0.5 MVA is integrated into the test system. Test results show that system voltage is stable at high PV penetration levels. Increase in load causes voltage instability, in which voltage drops below its allowable operating limit. Thus, increase in PV penetration level does not improve system voltage stability because the system experiences voltage collapse during line outage.

  17. The Legacy of the Georgetown College Observatory (D.C.)

    Science.gov (United States)

    Caron, Laura; Maglieri, Grace; Seitzer, Patrick

    2018-01-01

    Founded in 1841 as part of a nascent worldwide network of Jesuit-run astronomical observatories, the Georgetown College Observatory of Georgetown University in Washington, D.C. has been home to more than 125 years of astronomical research, from Father Curley’s calculations of the latitude and longitude of D.C. to Father McNally’s award-winning solar eclipse photography. But the impact of the Georgetown astronomy program was not limited to the observatory itself: it reached much further, into the local community and schools, and into the lives of everyone involved. This was never more apparent than under the directorship of Father Francis J Heyden, S.J., who arrived at Georgetown after World War II and stayed for almost three decades. He started a graduate program with over 90 graduates, hosting student researchers from local high schools and colleges, teaching graduate and undergraduate astronomy courses, and speaking at schools in the area, all while simultaneously managing Georgetown’s student radio station and hosting astronomical conferences on campus. Father Heyden’s research focused mainly on solar eclipses for geodetic purposes and planetary spectroscopy. But perhaps even more than research, Father Heyden dedicated his time and energy to the astronomy students, the notable of which include Vera Rubin, John P. Hagen of Project Vanguard, and a generation of Jesuit astronomers including Martin McCarthy, George Coyne, and Richard Boyle. Following the closure of the astronomy department in 1972, Father Heyden returned to Manila, where he had begun his astronomical career, to become Chief of the Solar Division at the Manila Observatory. His dedication to his work and to students serves as an inspiration for academic researchers across fields, and for the Georgetown University Astronomical Society, which, even in the absence of a formal astronomy program at Georgetown, continues his work in education and outreach today. In 1987, almost 150 years after its

  18. A Solar Chimney for renewable energy production: thermo-fluid dynamic optimization by CFD analyses

    Science.gov (United States)

    Montelpare, S.; D'Alessandro, V.; Zoppi, A.; Costanzo, E.

    2017-11-01

    This paper analyzes the performance of a solar tower designed for renewable energy production. The Solar Chimney Power Plant (SCPP) involves technology that converts solar energy by means of three basic components: a large circular solar collector, a high tower in the center of the collector and a turbine generator inside the chimney. SCPPs are characterized by long term operational life, low maintenance costs, zero use of fuels, no use of water and no emissions of greenhouse gases. The main problem of this technology is the low energy global conversion coefficient due to the presence of four conversions: solar radiation > thermal energy > kinetic energy > mechanical energy > electric energy. This paper defines its starting point from the well known power plant of Manzanares in order to calibrate a numerical model based on finite volumes. Following that, a solar tower with reduced dimensions was designed and an analysis on various geometric parameters was conducted: on the inlet section, on the collector slope, and on the fillet radius among the SUPP sections. Once the optimal solution was identified, a curved deflectors able to induce a flow swirl along the vertical tower axis was designed.

  19. An astronomical observatory for Peru

    Science.gov (United States)

    del Mar, Juan Quintanilla; Sicardy, Bruno; Giraldo, Víctor Ayma; Callo, Víctor Raúl Aguilar

    2011-06-01

    Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.

  20. Astronomical databases of Nikolaev Observatory

    Science.gov (United States)

    Protsyuk, Y.; Mazhaev, A.

    2008-07-01

    Several astronomical databases were created at Nikolaev Observatory during the last years. The databases are built by using MySQL search engine and PHP scripts. They are available on NAO web-site http://www.mao.nikolaev.ua.

  1. Geomagnetic Observatory Database February 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA National Centers for Environmental Information (formerly National Geophysical Data Center) maintains an active database of worldwide geomagnetic observatory...

  2. The South African astronomical observatory

    International Nuclear Information System (INIS)

    Feast, M.

    1985-01-01

    A few examples of the activities of the South African Astronomical Observatory are discussed. This includes the studying of stellar evolution, dust around stars, the determination of distances to galaxies and collaboration with space experiments

  3. The South African Astronomical Observatory

    International Nuclear Information System (INIS)

    1988-01-01

    The geographical position, climate and equipment at the South African Astronomical Observatory (SAAO), together with the enthusiasm and efforts of SAAO scientific and technical staff and of visiting scientists, have enabled the Observatory to make a major contribution to the fields of astrophysics and cosmology. During 1987 the SAAO has been involved in studies of the following: supernovae; galaxies, including Seyfert galaxies; celestial x-ray sources; magellanic clouds; pulsating variables; galatic structure; binary star phenomena; nebulae; interstellar matter and stellar astrophysics

  4. Deciphering solar magnetic activity. I. On the relationship between the sunspot cycle and the evolution of small magnetic features

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Scott W.; Wang, Xin; Markel, Robert S.; Thompson, Michael J. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); Leamon, Robert J.; Malanushenko, Anna V. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Davey, Alisdair R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Howe, Rachel [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Krista, Larisza D. [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80205 (United States); Cirtain, Jonathan W. [Marshall Space Flight Center, Code ZP13, Huntsville, AL 35812 (United States); Gurman, Joseph B.; Pesnell, William D., E-mail: mscott@ucar.edu [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-09-01

    Sunspots are a canonical marker of the Sun's internal magnetic field which flips polarity every ∼22 yr. The principal variation of sunspots, an ∼11 yr variation, modulates the amount of the magnetic field that pierces the solar surface and drives significant variations in our star's radiative, particulate, and eruptive output over that period. This paper presents observations from the Solar and Heliospheric Observatory and Solar Dynamics Observatory indicating that the 11 yr sunspot variation is intrinsically tied to the spatio-temporal overlap of the activity bands belonging to the 22 yr magnetic activity cycle. Using a systematic analysis of ubiquitous coronal brightpoints and the magnetic scale on which they appear to form, we show that the landmarks of sunspot cycle 23 can be explained by considering the evolution and interaction of the overlapping activity bands of the longer-scale variability.

  5. The Lowell Observatory Predoctoral Scholar Program

    Science.gov (United States)

    Prato, Lisa; Nofi, Larissa

    2018-01-01

    Lowell Observatory is pleased to solicit applications for our Predoctoral Scholar Fellowship Program. Now beginning its tenth year, this program is designed to provide unique research opportunities to graduate students in good standing, currently enrolled at Ph.D. granting institutions. Lowell staff research spans a wide range of topics, from astronomical instrumentation, to icy bodies in our solar system, exoplanet science, stellar populations, star formation, and dwarf galaxies. Strong collaborations, the new Ph.D. program at Northern Arizona University, and cooperative links across the greater Flagstaff astronomical community create a powerful multi-institutional locus in northern Arizona. Lowell Observatory's new 4.3 meter Discovery Channel Telescope is operating at full science capacity and boasts some of the most cutting-edge and exciting capabilities available in optical/infrared astronomy. Student research is expected to lead to a thesis dissertation appropriate for graduation at the doctoral level at the student's home institution. For more information, see http://www2.lowell.edu/rsch/predoc.php and links therein. Applications for Fall 2018 are due by May 1, 2018; alternate application dates will be considered on an individual basis.

  6. SPASE, Metadata, and the Heliophysics Virtual Observatories

    Science.gov (United States)

    Thieman, James; King, Todd; Roberts, Aaron

    2010-01-01

    To provide data search and access capability in the field of Heliophysics (the study of the Sun and its effects on the Solar System, especially the Earth) a number of Virtual Observatories (VO) have been established both via direct funding from the U.S. National Aeronautics and Space Administration (NASA) and through other funding agencies in the U.S. and worldwide. At least 15 systems can be labeled as Virtual Observatories in the Heliophysics community, 9 of them funded by NASA. The problem is that different metadata and data search approaches are used by these VO's and a search for data relevant to a particular research question can involve consulting with multiple VO's - needing to learn a different approach for finding and acquiring data for each. The Space Physics Archive Search and Extract (SPASE) project is intended to provide a common data model for Heliophysics data and therefore a common set of metadata for searches of the VO's. The SPASE Data Model has been developed through the common efforts of the Heliophysics Data and Model Consortium (HDMC) representatives over a number of years. We currently have released Version 2.1 of the Data Model. The advantages and disadvantages of the Data Model will be discussed along with the plans for the future. Recent changes requested by new members of the SPASE community indicate some of the directions for further development.

  7. The sunspot databases of the Debrecen Observatory

    Science.gov (United States)

    Baranyi, Tünde; Gyori, Lajos; Ludmány, András

    2015-08-01

    We present the sunspot data bases and online tools available in the Debrecen Heliophysical Observatory: the DPD (Debrecen Photoheliographic Data, 1974 -), the SDD (SOHO/MDI-Debrecen Data, 1996-2010), the HMIDD (SDO/HMI-Debrecen Data, HMIDD, 2010-), the revised version of Greenwich Photoheliographic Data (GPR, 1874-1976) presented together with the Hungarian Historical Solar Drawings (HHSD, 1872-1919). These are the most detailed and reliable documentations of the sunspot activity in the relevant time intervals. They are very useful for studying sunspot group evolution on various time scales from hours to weeks. Time-dependent differences between the available long-term sunspot databases are investigated and cross-calibration factors are determined between them. This work has received funding from the European Community's Seventh Framework Programme (FP7/2012-2015) under grant agreement No. 284461 (eHEROES).

  8. VESPA: A community-driven Virtual Observatory in Planetary Science

    Czech Academy of Sciences Publication Activity Database

    Erard, S.; Cecconi, B.; Le Sidaner, P.; Rossi, A. P.; Capria, M.T.; Schmitt, B.; Génot, V.; André, N.; Vandaele, A. C.; Scherf, M.; Hueso, R.; Määttänen, A.; Thuillot, W.; Carry, B.; Achilleos, N.; Marmo, C.; Santolík, Ondřej; Benson, K.; Fernique, P.; Beigbeder, L.; Millour, E.; Rousseau, B.; Andrieu, F.; Chauvin, C.; Minin, M.; Ivanoski, S.; Longobardo, A.; Bollard, P.; Albert, D.; Gangloff, M.; Jourdane, N.; Bouchemit, M.; Glorian, J. M.; Trompet, L.; Al-Ubaidi, T.; Juaristi, J.; Desmars, J.; Guio, P.; Delaa, O.; Lagain, A.; Souček, Jan; Píša, David

    2018-01-01

    Roč. 150, SI (2018), s. 65-85 ISSN 0032-0633 EU Projects: European Commission(XE) 654208 - EPN2020-RI Institutional support: RVO:68378289 Keywords : Virtual Observatory * Solar System * GIS Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 1.892, year: 2016 https://www.sciencedirect.com/science/article/pii/S0032063316304937#gs1

  9. Improved thermodynamics of the dense solar plasma and molecular-dynamics simulations of the nuclear-reaction rates

    Science.gov (United States)

    Mao, Dan

    available, there is no alternative source. The official OPAL tables, however, have disadvantages. First, they are inflexible regarding the chemical mix, which is set once and for all by the producers of the tables. Our equation of state will allow the user to choose, in principle, an arbitrary mix. Second, the OPAL tables by their very nature are limited by the errors of interpolation within tables. The second equation of state model is a density expansion based on the Feynman-Kac path-integral formalism. By making use of the equivalence of quantum Hamiltonian matrix and the classical action of closed and open filaments (paths), an analytic formalism of equation of state. Although the character of density expansion limits its application, the formalism can still be valid in most region in the Sun. Our work provides the link between the abstract theoretical formalism that was developed in the 1990s and a numerically smooth realization that can be used in solar and stellar models. Since it is so far the most exact and systematic approach for an EOS, it provides another way to study the influence of different very fine physical effects, despite considerable limitations in its domain of applicability. In the nuclear-reaction part of the thesis, we have used a molecular-dynamics method to simulate the motion of protons in a hydrogen plasma (which is a good approximation for this purpose). Quantum tunneling explains why nuclear fusion can occur in the first place, considering the "low" temperature in the solar core. It is well known that this tunneling is enhanced (which leads to higher nuclear reaction rates) in the presence of Coulomb screening. In the 1950, Salpeter formulated a theory based on the static-screened Coulomb potential, as derived by Debye and H=FCckel in the 1920s. As expected, Salpeter obtained enhanced reaction rates. But from our simulation, we confirmed the results of a recent controversy about the existence of a dynamic effect. Since the bulk of fusion

  10. Design and dynamic behaviour of a cold storage system combined with a solar powered thermoacoustic refrigerator

    International Nuclear Information System (INIS)

    Perier-Muzet, Maxime; Bedecarrats, Jean-Pierre; Stouffs, Pascal; Castaing-Lasvignottes, Jean

    2014-01-01

    A heat powered thermoacoustic refrigerator consists in a thermoacoustic engine that produces acoustic work utilizing heat, coupled to a thermoacoustic cooler that converts this acoustic energy into cooling effect. These machines have already proved their capability in laboratory or in space refrigeration. Previous studies have also demonstrated the possibility of using concentrated solar energy as thermal energy sources for low power heat driven thermoacoustic refrigerators. As other solar refrigeration systems, even if the cooling demand generally increases with the intensity of the solar radiation, one of the major difficulties is to insure a frigorific power supply when there is no, or low, solar radiation. The aim of this work is to study a kW scale solar thermoacoustic refrigerator capable to reach temperatures of the industrial refrigeration domain. This refrigerator is combined with a latent cold storage in order to guarantee a sufficient cooling capacity to face to refrigeration loads in spite of the production fluctuations. A description of the studied prototype is done and the model developed to describe the transient behaviour of the main components of this machine is introduced. The results obtained with a simulation of one week with real solar radiations are presented and the behaviour and the energetic performances of the entire system are analysed. Finally the impact of the sizing of the cold storage system is discussed. With the best storage design, the system is capable to supply a cooling power of 400 W at a temperature equal or lower than −20 °C with an average Coefficient Of Performance of the solar thermoacoustic refrigerator equal to 21%

  11. The Arecibo Observatory Space Academy

    Science.gov (United States)

    Rodriguez-Ford, Linda A.; Fernanda Zambrano Marin, Luisa; Aponte Hernandez, Betzaida; Soto, Sujeily; Rivera-Valentin, Edgard G.

    2016-10-01

    The Arecibo Observatory Space Academy (AOSA) is an intense fifteen-week pre-college research program for qualified high school students residing in Puerto Rico, which includes ten days for hands-on, on site research activities. Our mission is to prepare students for their professional careers by allowing them to receive an independent and collaborative research experience on topics related to the multidisciplinary field of space science. Our objectives are to (1) supplement the student's STEM education via inquiry-based learning and indirect teaching methods, (2) immerse students in an ESL environment, further developing their verbal and written presentation skills, and (3) foster in every student an interest in the STEM fields by harnessing their natural curiosity and knowledge in order to further develop their critical thinking and investigation skills. Students interested in participating in the program go through an application, interview and trial period before being offered admission. They are welcomed as candidates the first weeks, and later become cadets while experiencing designing, proposing, and conducting research projects focusing in fields like Physics, Astronomy, Geology, Chemistry, and Engineering. Each individual is evaluated with program compatibility based on peer interaction, preparation, participation, and contribution to class, group dynamics, attitude, challenges, and inquiry. This helps to ensure that specialized attention can be given to students who demonstrate a dedication and desire to learn. Deciding how to proceed in the face of setbacks and unexpected problems is central to the learning experience. At the end of the semester, students present their research to the program mentors, peers, and scientific staff. This year, AOSA students also focused on science communication and were trained by NASA's FameLab. Students additionally presented their research at this year's International Space Development Conference (ISDC), which was held in

  12. Sierra Stars Observatory Network: An Accessible Global Network

    Science.gov (United States)

    Williams, Richard; Beshore, Edward

    2011-03-01

    The Sierra Stars Observatory Network (SSON) is a unique partnership among professional observatories that provides its users with affordable high-quality calibrated image data. SSON comprises observatories in the Northern and Southern Hemisphere and is in the process of expanding to a truly global network capable of covering the entire sky 24 hours a day in the near future. The goal of SSON is to serve the needs of science-based projects and programs. Colleges, universities, institutions, and individuals use SSON for their education and research projects. The mission of SSON is to promote and expand the use of its facilities among the thousands of colleges and schools worldwide that do not have access to professional-quality automated observatory systems to use for astronomy education and research. With appropriate leadership and guidance educators can use SSON to help teach astronomy and do meaningful scientific projects. The relatively small cost of using SSON for this type of work makes it affordable and accessible for educators to start using immediately. Remote observatory services like SSON need to evolve to better support education and research initiatives of colleges, institutions and individual investigators. To meet these needs, SSON is developing a sophisticated interactive scheduling system to integrate among the nodes of the observatory network. This will enable more dynamic observations, including immediate priority interrupts, acquiring moving objects using ephemeris data, and more.

  13. Detection of non-absorbing charge dynamics via refractive index change in dye-sensitized solar cells.

    Science.gov (United States)

    Kuwahara, Shota; Hata, Hiroaki; Taya, Soichiro; Maeda, Naotaka; Shen, Qing; Toyoda, Taro; Katayama, Kenji

    2013-04-28

    The carrier dynamics in dye-sensitized solar cells was investigated by using the transient grating, in addition to the transient absorption method and transient photocurrent method on the order of microseconds to seconds. The signals for the same sample were obtained under a short-circuit condition to compare the carrier dynamics via refractive index change with the transient photocurrent measurement. Optically silent carrier dynamics by transient absorption have been successfully observed via a refractive index change. The corresponding signal components were originated from the charge dynamics at the solid/liquid interface, especially on the liquid side; rearrangement or diffusion motion of charged redox species occurred when the injected electrons were trapped at the TiO2 surface and when the electron-electrolyte recombination occurred at the interface. The assignments were confirmed from the dependence on the viscosity of the solvent and the presence of 4-tert-butyl pyridine. As the viscosity of the solvent increased, the rearrangement and the motion of the charged redox species were delayed. Since the rearrangement dynamics was changed by the presence of 4-tert-butyl pyridine, it affected not only the TiO2 surface but also the redox species close to the interface.

  14. Astrophysical Sources of Cosmic Rays and Related Measurements with the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Correlation of the highest energy cosmic rays with nearby extragalactic objects in Pierre Auger Observatory data; (2) Discriminating potential astrophysical sources of the highest energy cosmic rays with the Pierre Auger Observatory; (3) Intrinsic anisotropy of the UHECR from the Pierre Auger Observatory; (4) Ultra-high energy photon studies with the Pierre Auger Observatory; (5) Limits on the flux of diffuse ultra high energy neutrinos set using the Pierre Auger Observatory; (6) Search for sidereal modulation of the arrival directions of events recorded at the Pierre Auger Observatory; (7) Cosmic Ray Solar Modulation Studies in the Pierre Auger Observatory; (8) Investigation of the Displacement Angle of the Highest Energy Cosmic Rays Caused by the Galactic Magnetic Field; (9) Search for coincidences with astrophysical transients in Pierre Auger Observatory data; and (10) An alternative method for determining the energy of hybrid events at the Pierre Auger Observatory.

  15. Dynamic mass exchange in doubly degenerate binaries. I - 0.9 and 1.2 solar mass stars

    International Nuclear Information System (INIS)

    Benz, W.; Cameron, A.G.W.; Press, W.H.; Bowers, R.L.

    1990-01-01

    The dynamic mass exchange process in doubly degenerate binaries was investigated using a three-dimensional numerical simulation of the evolution of a doubly degenerate binary system in which the primary is a 1.2-solar-mass white dwarf and the Roche lobe filling secondary is a 0.9-solar-mass dwarf. The results show that, in a little more than two orbital periods, the secondary is completely destroyed and transformed into a thick disk orbiting about the primary. Since only a very small fraction of the mass (0.0063 solar mass) escapes the system, the evolution of the binary results in the formation of a massive object. This object is composed of three parts, the initial white dwarf primary, a very hot pressure-supported spherical envelope, and a rotationally supported outer disk. The evolution of the system can be understood in terms of a simple analytical model where it is shown that the angular momentum carried by the mass during the transfer and stored in the disk determines the evolution of the system. 34 refs

  16. Superstorms of November 2003 and 2004: the role of solar wind driving in the ionosphere-thermosphere dynamics

    Science.gov (United States)

    Verkhoglyadova, O. P.; Komjathy, A.; Mannucci, A. J.; Mlynczak, M. G.; Hunt, L. A.; Paxton, L. J.

    2017-12-01

    We revisit three complex superstorms of 19-20 November 2003, 7-8 November 2004 and 9-11 November 2004 to analyze ionosphere-thermosphere (IT) effects driven by different solar wind structures. We distinguish structures associated with ICMEs and their upstream sheaths. The efficiencies of the solar wind-magnetosphere connection throughout the storms are estimated by coupling functions. The daytime IT responses to the complex driving are characterized by combining measurements of characteristic IT parameters. We focus on low- and middle-latitude TEC, global thermospheric infrared nitric oxide emission, composition ratio and locations of the auroral boundary obtained from multiple satellite platforms and ground-based measurements (GPS, TIMED/SABER, TIMED/GUVI, DMSP/SSUSI). A variety of metrics are utilized to examine IT phenomena at 1 hour time scales. It is well-known that the November storm periods featured TEC responses that did not fit a typical pattern. The role of direct driving of IT dynamics by solar wind structures and the role of IT pre-conditioning in these storms are examined to explain the complex unusual ionospheric responses. We identify IT feedback effects that can be important for long-lasting strong storms.

  17. Integrated solar-assisted heat pumps for water heating coupled to gas burners; control criteria for dynamic operation

    International Nuclear Information System (INIS)

    Scarpa, F.; Tagliafico, L.A.; Tagliafico, G.

    2011-01-01

    A direct expansion integrated solar-assisted heat pump (ISAHP) is compared to a traditional flat plate solar panel for low temperature (45 deg. C) water heating applications. The (simulated) comparison is accomplished assuming both the devices are energy supplemented with an auxiliary standard gas burner, to provide the typical heat duty of a four-member family. Literature dynamical models of the systems involved have been used to calculate the main performance figures in a context of actual climatic conditions and typical stochastic user demand. The paper highlights new heat pump control concepts, needed when maximum energy savings are the main goal of the apparatus for given user demand. Simulations confirm the high collector efficiency of the ISAHP when its panel/evaporator works at temperature close to the ambient one. The device, with respect to a flat plate solar water heater, shows a doubled performance, so that it can do the same task just using an unglazed panel with roughly half of the surface.

  18. Communicating Solar Astronomy to the public

    Science.gov (United States)

    Yaji, Kentaro; Solar Observatory NAOJ, The

    2015-08-01

    The Sun is the nearest star to us, so that the public is greatly interested in the Sun itself and in solar activity. The Solar Observatory, National Astronomical Observatory of Japan is one of the solar research divisions. Various data of the Sun obtained with our instruments, systematically accumulated more than one hundred years since 1910s, are open to not only researchers but also the public as online database. So, we have many chances that the public request solar images for the education and the media. In addition, we release daily solar observation informations on the web and with social media and guide visitors to our observation facilities. It is reviewed about the public relations and outreach activities of the Solar Observatory, including recent solar observation topics.

  19. Fundamental Astronomy and Solar System Dynamics : Invited Papers Honoring Prof. Walter Fricke on the occasion of his 70th birthday

    CERN Document Server

    Lieske, J; Seidelmann, P

    1986-01-01

    "Fundamental Astronomy and Solar System Dynamics", a program of invited papers honoring Professor Walter Fricke, who for thirty years has been Director of the Astronomisches Rechen lnstitut in Heidelberg, was held at the Thompson Conference Center of the University of Texas at Austin on Wednesday 27 March 1985 on the occasion of his seventieth birthday and retirement as Director of ARl. Professor Fricke's contributions to astronomy encompass the areas of galactic dynamics, radial velocities, stellar statistics. the fundamental reference system and the constant of precession. Participants were welcomed to the Uni versi ty of Texas by Professor J. Parker Lamb, Chairman of the Department of Aerospace Engineering and Engineering Mechanics. The presentations ranged from discussions of astrometric problems concerned with the reference system, the constant of precession, major and minor planet observations, planetary ephemerides and lunar and satellite laser ranging, to a study of disc galaxies in massive halos. The...

  20. Revealing the ultrafast charge carrier dynamics in organo metal halide perovskite solar cell materials using time resolved THz spectroscopy

    Science.gov (United States)

    Ponseca, C. S., Jr.; Sundström, V.

    2016-03-01

    Ultrafast charge carrier dynamics in organo metal halide perovskite has been probed using time resolved terahertz (THz) spectroscopy (TRTS). Current literature on its early time characteristics is unanimous: sub-ps charge carrier generation, highly mobile charges and very slow recombination rationalizing the exceptionally high power conversion efficiency for a solution processed solar cell material. Electron injection from MAPbI3 to nanoparticles (NP) of TiO2 is found to be sub-ps while Al2O3 NPs do not alter charge dynamics. Charge transfer to organic electrodes, Spiro-OMeTAD and PCBM, is sub-ps and few hundreds of ps respectively, which is influenced by the alignment of energy bands. It is surmised that minimizing defects/trap states is key in optimizing charge carrier extraction from these materials.

  1. Lightning activity and radar observations of the multicell thunderstorm system passing over Swider Observatory (Poland) on 19 July 2015 and its dynamic and electric charge structure obtained from the WRF_ELEC model

    Science.gov (United States)

    Kubicki, Marek; Konarski, Jerzy; Gajda, Wojciech; Barański, Piotr; Guzikowski, Jakub; Kryza, Maciej

    2017-04-01

    In this work we present preliminary results on the thunderstorm event at IG PAS Swider Geophysical Observatory (52.12°N, 21.25°E, geomagnetic latitude 50.5°N, near Warsaw, Poland) on 19 July 2015. The storm was caused by the abrasion of the warm front that stretched almost latitudinaly and cold front moving from the west to the east. Warm continental-tropical arrived at southern and eastern part of the country and the rest was covered by cool polar-maritime airmass. The storm had the squall-line character of approximately 100 km length and consisted of several cells, and the height of the cumulonimbus (Cb) cloud base was 1 km and top was 14 km, as inferred from the analysis of CAPPI (Constant Altitude Plan Position Indicator), CMAX (Column Maximum Display), MLVCUT (Multiple-Line Vertical Cut) radar map products from POLRAD observations at Institute of Meteorology and Water Management - National Research Institute (IMWM-NRI), Legionowo station. In our paper we have discussed the obtained results of the post-time analysis of lightning activity and radar observations of the extended multicells thunderstorm system passing over IG PAS Swider Geophysical Observatory, on 19 July 2015 together with its dynamic and electric charge structure obtained from the WRF_ELEC model. We have used the archive data from the Polish National Lightning Location and Detection System PERUN (provided by IMWM-NRI) together with radar data obtained from the Doppler meteorological radar METEOR 1500C at Legionowo. Additionally, during the approach, passing over and moving away phase of the thunderstorm system, we have gathered the simultaneous and continuous recordings of E-field, the electric conductivity of air and the independent supplementary reference lightning detections delivered by the Swider measuring station of the Local Lightning Detection Network (LLDN) operated in Warsaw region. These data have given us a new possibility to acquire many valuable information about the

  2. Dynamics of the Solar Wind Electromagnetic Energy Transmission Into Magnetosphere during Large Geomagnetic Storms

    Science.gov (United States)

    Kuznetsova, Tamara; Laptukhov, Alexej; Petrov, Valery

    Causes of the geomagnetic activity (GA) in the report are divided into temporal changes of the solar wind parameters and the changes of the geomagnetic moment orientation relative directions of the solar wind electric and magnetic fields. Based on our previous study we concluded that a reconnection based on determining role of mutual orientation of the solar wind electric field and geomagnetic moment taking into account effects of the Earth's orbital and daily motions is the most effective compared with existing mechanisms. At present a reconnection as paradigma that has applications in broad fields of physics needs analysis of experimental facts to be developed. In terms of reconnection it is important not only mutual orientation of vectors describing physics of interaction region but and reconnection rate which depends from rate of energy flux to those regions where the reconnection is permitted. Applied to magnetosphere these regions first of all are dayside magnetopause and polar caps. Influence of rate of the energy flux to the lobe magnetopause (based on calculations of the Poyting electromagnetic flux component controlling the reconnection rate along the solar wind velocity Pv) on planetary GA (Dst, Kp indices) is investigated at different phases of geomagnetic storms. We study also the rate of energy flux to the polar caps during storms (based on calculations of the Poyting flux vector component along the geomagnetic moment Pm) and its influence on magnetic activity in the polar ionosphere: at the auroral zone (AU,AL indices). Results allow to evaluate contributions of high and low latitude sources of electromagnetic energy to the storm development and also to clear mechanism of the electromagnetic energy transmission from the solar wind to the magnetosphere. We evaluate too power of the solar wind electromagnetic energy during well-known large storms and compare result with power of the energy sources of other geophysical processes (atmosphere, ocean

  3. Heliospheric pick-up ions influencing thermodynamics and dynamics of the distant solar wind

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2002-01-01

    Full Text Available Neutral interstellar H-atoms penetrate into the inner heliosphere and upon the event of ionization are converted into pick-up ions (PUIs. The magnetized solar wind flow incorporates these ions into the plasma bulk and enforces their co-motion. By nonlinear interactions with wind-entrained Alfvén waves, these ions are then processed in the comoving velocity space. The complete pick-up process is connected with forces acting back to the original solar wind ion flow, thereby decelerating and heating the solar wind plasma. As we show here, the resulting deceleration cannot be treated as a pure loading effect, but requires adequate consideration of the action of the pressure of PUI-scattered waves operating by the PUI pressure gradient. Hereby, it is important to take into proper account the stochastic acceleration which PUIs suffer from at their convection out of the inner heliosphere by quasi-linear interactions with MHD turbulences. Only then can the presently reported VOYAGER observations of solar wind decelerations and heatings in the outer heliosphere be understood in view of the most likely values of interstellar gas parameters, such as an H-atom density of 0.12 cm-3 . Solar wind protons (SWPs appear to be globally heated in their motion to larger solar distances. Ascribing the needed heat transfer to the action of suprathermal PUIs, which drive MHD waves that are partly absorbed by SWPs, in order to establish the observed SWP polytropy, we can obtain a quantitative expression for the solar wind proton pressure as a function of solar distance. This expression clearly shows the change from an adiabatic to a quasi-polytropic SWP behaviour with a decreasing polytropic index at increasing distances. This also allows one to calculate the average percentage of initial pick-up energy fed into the thermal proton energy. In a first order evaluation of this expression, we can estimate that about 10% of the initial PUI injection energy is eventually

  4. Electricity and gas market observatory. 2. Quarter 2008

    International Nuclear Information System (INIS)

    2008-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). Since the 1 of July 2007, all customers can choose their gas and electricity suppliers. Content: A - The electricity market: The retail electricity market (Introduction, Customer segments and their respective weight, Status at June 30, 2008, Dynamic analysis: 2. Quarter 2008); The wholesale electricity market (Introduction, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market); B - The gas market: The retail gas market (Introduction, Customer segments and their respective weight, Status on June 30, 2008, Dynamic analysis: 2. Quarter 2008); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  5. Electricity and gas market observatory 1. Quarter 2009

    International Nuclear Information System (INIS)

    2009-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). Since the 1. of July 2007, all customers can choose their gas and electricity suppliers. Content: A - The electricity market: The retail electricity market (Introduction, Customer segments and their respective weight, Status on March 31, 2009, Dynamic analysis: 1. Quarter 2009), The wholesale electricity market (Introduction, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market). B - The gas market: The retail gas market (Introduction, Customer segments and their respective weight, Status on March 31. 2009, Dynamic analysis: 1. Quarter 2009), The wholesale gas market (Main steps in the French Wholesale gas market, Gas pricing and gas markets in Europe, The wholesale market in France, Prices on the French wholesale market and European comparison, Concentration of the French gas market) C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  6. Electricity and gas market observatory. 4. Quarter 2008

    International Nuclear Information System (INIS)

    2008-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). Since the 1 of July 2007, all customers can choose their gas and electricity suppliers. Content: A - The electricity market: The retail electricity market (Introduction, Customer segments and their respective weight, Status on December 31, 2008, Dynamic analysis: 4. Quarter 2008); The wholesale electricity market (Introduction, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market); B - The gas market: The retail gas market (Introduction, Customer segments and their respective weight, Status on December 31, 2008, Dynamic analysis: 4. Quarter 2008); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France, Prices on the French wholesale market and European comparison, Concentration of the French gas market); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  7. Electricity and gas market observatory. 1. Quarter 2008

    International Nuclear Information System (INIS)

    2008-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). Since the 1. of July 2007, all customers can choose their gas and electricity suppliers. Content: A - The electricity market: The retail electricity market (Introduction, Customer segments and their respective weight, Status at March 31, 2007, Dynamic analysis: 1. Quarter 2008); The wholesale electricity market (Introduction, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market); B - The gas market: The retail gas market (Introduction, Customer segments and their respective weight, Status on March 31, 2008, Dynamic analysis: 1. Quarter 2008); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France, Striking fact of the first quarter 2008); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  8. Electricity and gas market observatory. 4. Quarter 2007

    International Nuclear Information System (INIS)

    2007-01-01

    The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). Since the 1. of July 2007, all customers can choose their gas and electricity suppliers. Content: A - The electricity market: The retail electricity market (Introduction, Customer segments and their respective weight, Status at December 31, 2007, Dynamic analysis: 4. Quarter 2007); The wholesale electricity market (Introduction, Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking fact of the fourth quarter 2007); B - The gas market: The retail gas market (Introduction, Customer segments and their respective weight, Status on December 31. 2007, Dynamic analysis: 4. Quarter 2007); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France, Striking fact of the fourth quarter 2007); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  9. Taurus Hill Observatory Scientific Observations for Pulkova Observatory during the 2016-2017 Season

    Science.gov (United States)

    Hentunen, V.-P.; Haukka, H.; Heikkinen, E.; Salmi, T.; Juutilainen, J.

    2017-09-01

    Taurus Hill Observatory (THO), observatory code A95, is an amateur observatory located in Varkaus, Finland. The observatory is maintained by the local astronomical association Warkauden Kassiopeia. THO research team has observed and measured various stellar objects and phenomena. Observatory has mainly focused on exoplanet light curve measurements, observing the gamma rays burst, supernova discoveries and monitoring. We also do long term monitoring projects.

  10. To develop a dynamic model of a collector loop for purpose of improved control of solar heating and cooling. Final technical report. [TRNSYS code

    Energy Technology Data Exchange (ETDEWEB)

    Herczfeld, P R; Fischl, R

    1980-01-01

    The program objectives were to (1) assess the feasibility of using the TRNSYS computer code for solar heating and cooling control studies and modify it wherever possible, and (2) develop a new dynamic model of the solar collector which reflects the performance of the collector under transient conditions. Also, the sensitivity of the performance of this model to the various system parameters such as collector time constants, flow rates, turn-on and turn-off temperature set points, solar insolation, etc., was studied. Results are presented and discussed. (WHK)

  11. System dynamic model and charging control of lead-acid battery for stand-alone solar PV system

    KAUST Repository

    Huang, B.J.

    2010-05-01

    The lead-acid battery which is widely used in stand-alone solar system is easily damaged by a poor charging control which causes overcharging. The battery charging control is thus usually designed to stop charging after the overcharge point. This will reduce the storage energy capacity and reduce the service time in electricity supply. The design of charging control system however requires a good understanding of the system dynamic behaviour of the battery first. In the present study, a first-order system dynamics model of lead-acid battery at different operating points near the overcharge voltage was derived experimentally, from which a charging control system based on PI algorithm was developed using PWM charging technique. The feedback control system for battery charging after the overcharge point (14 V) was designed to compromise between the set-point response and the disturbance rejection. The experimental results show that the control system can suppress the battery voltage overshoot within 0.1 V when the solar irradiation is suddenly changed from 337 to 843 W/m2. A long-term outdoor test for a solar LED lighting system shows that the battery voltage never exceeded 14.1 V for the set point 14 V and the control system can prevent the battery from overcharging. The test result also indicates that the control system is able to increase the charged energy by 78%, as compared to the case that the charging stops after the overcharge point (14 V). © 2010 Elsevier Ltd. All rights reserved.

  12. GEOSCOPE Observatory Recent Developments

    Science.gov (United States)

    Leroy, N.; Pardo, C.; Bonaime, S.; Stutzmann, E.; Maggi, A.

    2010-12-01

    The GEOSCOPE observatory consists of a global seismic network and a data center. The 31 GEOSCOPE stations are installed in 19 countries, across all continents and on islands throughout the oceans. They are equipped with three component very broadband seismometers (STS1 or STS2) and 24 or 26 bit digitizers, as required by the Federation of Seismic Digital Network (FDSN). In most stations, a pressure gauge and a thermometer are also installed. Currently, 23 stations send data in real or near real time to GEOSCOPE Data Center and tsunami warning centers. In 2009, two stations (SSB and PPTF) have been equipped with warpless base plates. Analysis of one year of data shows that the new installation decreases long period noise (20s to 1000s) by 10 db on horizontal components. SSB is now rated in the top ten long period stations for horizontal components according to the LDEO criteria. In 2010, Stations COYC, PEL and RER have been upgraded with Q330HR, Metrozet electronics and warpless base plates. They have been calibrated with the calibration table CT-EW1 and the software jSeisCal and Calex-EW. Aluminum jars are now installed instead of glass bells. A vacuum of 100 mbars is applied in the jars which improves thermal insulation of the seismometers and reduces moisture and long-term corrosion in the sensor. A new station RODM has just been installed in Rodrigues Island in Mauritius with standard Geoscope STS2 setup: STS2 seismometer on a granite base plate and covered by cooking pot and thermal insulation, it is connected to Q330HR digitizer, active lightning protection, Seiscomp PC and real-time internet connection. Continuous data of all stations are collected in real time or with a delay by the GEOSCOPE Data Center in Paris where they are validated, archived and made available to the international scientific community. Data are freely available to users by different interfaces according data types (see : http://geoscope.ipgp.fr) - Continuous data in real time coming

  13. Responses of Solar Irradiance and the Ionosphere to an Intense Activity Region

    Science.gov (United States)

    Chen, Yiding; Liu, Libo; Le, Huijun; Wan, Weixing

    2018-03-01

    Solar rotation (SR) variation dominates solar extremely ultraviolet (EUV) changes on the timescale of days. The F10.7 index is usually used as an indicator for solar EUV. The SR variation of F10.7 significantly enhanced during the 2008th-2009th Carrington rotations (CRs) owing to an intense active region; F10.7 increased about 180 units during that SR period. That was the most prominent SR variation of F10.7 during solar cycle 23. In this paper, global electron content (GEC) is used to investigate ionospheric response to that strong variation of solar irradiance indicated by F10.7. The variation of GEC with F10.7 was anomalous (GEC-F10.7 slope significantly decreased) during the 2008th-2009th CRs; however, GEC versus EUV variation during that period was consistent with that during adjacent time intervals when using Solar Heliospheric Observatory/Solar EUV Monitor 26-34 nm EUV measurements. The reason is that F10.7 response to that intense active region was much stronger than EUV response; thus, the EUV-F10.7 slope decreased. We confirmed decreased EUV-F10.7 slope during the 2008th-2009th CRs for different wavelengths within 27-120 nm using Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Solar EUV Experiment high spectral resolution EUV measurements. And on the basis of Solar Heliospheric Observatory/Solar EUV Monitor EUV measurements during solar cycle 23, we further presented that EUV-F10.7 slope statistically tends to decrease when the SR variation of F10.7 significantly enhances. Moreover, we found that ionospheric time lag effect to EUV is exaggerated when using F10.7, owing to the time lag effect of EUV to F10.7.

  14. Griffith Observatory: Hollywood's Celestial Theater

    Science.gov (United States)

    Margolis, Emily A.; Dr. Stuart W. Leslie

    2018-01-01

    The Griffith Observatory, perched atop the Hollywood Hills, is perhaps the most recognizable observatory in the world. Since opening in 1935, this Los Angeles icon has brought millions of visitors closer to the heavens. Through an analysis of planning documentation, internal newsletters, media coverage, programming and exhibition design, I demonstrate how the Observatory’s Southern California location shaped its form and function. The astronomical community at nearby Mt. Wilson Observatory and Caltech informed the selection of instrumentation and programming, especially for presentations with the Observatory’s Zeiss Planetarium, the second installed in the United States. Meanwhile the Observatory staff called upon some of Hollywood’s best artists, model makers, and scriptwriters to translate the latest astronomical discoveries into spectacular audiovisual experiences, which were enhanced with Space Age technological displays on loan from Southern California’s aerospace companies. The influences of these three communities- professional astronomy, entertainment, and aerospace- persist today and continue to make Griffith Observatory one of the premiere sites of public astronomy in the country.

  15. FAST DIFFERENTIAL EMISSION MEASURE INVERSION OF SOLAR CORONAL DATA

    Energy Technology Data Exchange (ETDEWEB)

    Plowman, Joseph; Kankelborg, Charles; Martens, Petrus [Montana State University, Bozeman, MT 59717 (United States)

    2013-07-01

    We present a fast method for reconstructing differential emission measures (DEMs) using solar coronal data. The method consists of a fast, simple regularized inversion in conjunction with an iteration scheme for removal of residual negative emission measure. On average, it computes over 1000 DEMs s{sup -1} for a sample active region observed by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory, and achieves reduced chi-squared of order unity with no negative emission in all but a few test cases. The high performance of this method is especially relevant in the context of AIA, which images of order one million solar pixels per second. This paper describes the method, analyzes its fidelity, compares its performance and results with other DEM methods, and applies it to an active region and loop observed by AIA and by the Extreme-ultraviolet Imaging Spectrometer on Hinode.

  16. Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

    Science.gov (United States)

    Pitone, D. S.; Klein, J. R.; Twambly, B. J.

    1990-01-01

    Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X-ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the larg-angle pointing performance.

  17. Manifestations of dark energy in the dynamics of the Solar system

    NARCIS (Netherlands)

    Křížek, M.; Brandts, J.

    2010-01-01

    The expansion speed of the Universe is increasing (Glanz 1998). This acceleration is attributed to dark energy which acts almost uniformly everywhere (including the Solar system) and thus essentially influences the Hubble constant. Its current value on a distance of 1 AU is H0 = 10 m/(yr AU). This

  18. A dynamical approach in exploring the unknown mass in the Solar system using pulsar timing arrays

    Science.gov (United States)

    Guo, Y. J.; Lee, K. J.; Caballero, R. N.

    2018-04-01

    The error in the Solar system ephemeris will lead to dipolar correlations in the residuals of pulsar timing array for widely separated pulsars. In this paper, we utilize such correlated signals, and construct a Bayesian data-analysis framework to detect the unknown mass in the Solar system and to measure the orbital parameters. The algorithm is designed to calculate the waveform of the induced pulsar-timing residuals due to the unmodelled objects following the Keplerian orbits in the Solar system. The algorithm incorporates a Bayesian-analysis suit used to simultaneously analyse the pulsar-timing data of multiple pulsars to search for coherent waveforms, evaluate the detection significance of unknown objects, and to measure their parameters. When the object is not detectable, our algorithm can be used to place upper limits on the mass. The algorithm is verified using simulated data sets, and cross-checked with analytical calculations. We also investigate the capability of future pulsar-timing-array experiments in detecting the unknown objects. We expect that the future pulsar-timing data can limit the unknown massive objects in the Solar system to be lighter than 10-11-10-12 M⊙, or measure the mass of Jovian system to a fractional precision of 10-8-10-9.

  19. Visits to La Plata Observatory

    Science.gov (United States)

    Feinstein, A.

    1985-03-01

    La Plata Observatory will welcome visitors to ESO-La Silla that are willing to make a stop at Buenos Aires on their trip to Chile or on their way back. There is a nice guesthouse at the Observatory that can be used, for a couple of days or so, by astronomers interested in visiting the Observatory and delivering talks on their research work to the Argentine colleagues. No payments can, however, be made at present. La Plata is at 60 km from Buenos Aires. In the same area lie the Instituto de Astronomia y Fisica dei Espacio (IAFE), in Buenos Aires proper, and the Instituto Argentino de Radioastronomia (IAR). about 40 km from Buenos Aires on the way to La Plata. Those interested should contacl: Sr Decano Prof. Cesar A. Mondinalli, or Dr Alejandro Feinstein, Observatorio Astron6mico, Paseo dei Bosque, 1900 La Plata, Argentina. Telex: 31216 CESLA AR.

  20. Observation of the Kelvin–Helmholtz Instability in a Solar Prominence

    Science.gov (United States)

    Yang, Heesu; Xu, Zhi; Lim, Eun-Kyung; Kim, Sujin; Cho, Kyung-Suk; Kim, Yeon-Han; Chae, Jongchul; Cho, Kyuhyoun; Ji, Kaifan

    2018-04-01

    Many solar prominences end their lives in eruptions or abrupt disappearances that are associated with dynamical or thermal instabilities. Such instabilities are important because they may be responsible for energy transport and conversion. We present a clear observation of a streaming kink-mode Kelvin–Helmholtz Instability (KHI) taking place in a solar prominence using the Hα Lyot filter installed at the New Vacuum Solar Telescope, Fuxian-lake Solar Observatory in Yunnan, China. On one side of the prominence, a series of plasma blobs floated up from the chromosphere and streamed parallel to the limb. The plasma stream was accelerated to about 20–60 km s‑1 and then undulated. We found that 2″- and 5″-size vortices formed, floated along the stream, and then broke up. After the 5″-size vortex, a plasma ejection out of the stream was detected in the Solar Dynamics Observatory/Atmospheric Imaging Assembly images. Just before the formation of the 5″-size vortex, the stream displayed an oscillatory transverse motion with a period of 255 s with the amplitude growing at the rate of 0.001 s‑1. We attribute this oscillation of the stream and the subsequent formation of the vortex to the KHI triggered by velocity shear between the stream, guided by the magnetic field and the surrounding media. The plasma ejection suggests the transport of prominence material into the upper layer by the KHI in its nonlinear stage.

  1. Astronomical Research Using Virtual Observatories

    Directory of Open Access Journals (Sweden)

    M Tanaka

    2010-01-01

    Full Text Available The Virtual Observatory (VO for Astronomy is a framework that empowers astronomical research by providing standard methods to find, access, and utilize astronomical data archives distributed around the world. VO projects in the world have been strenuously developing VO software tools and/or portal systems. Interoperability among VO projects has been achieved with the VO standard protocols defined by the International Virtual Observatory Alliance (IVOA. As a result, VO technologies are now used in obtaining astronomical research results from a huge amount of data. We describe typical examples of astronomical research enabled by the astronomical VO, and describe how the VO technologies are used in the research.

  2. The South African Astronomical Observatory

    International Nuclear Information System (INIS)

    1989-01-01

    The research work discussed in this report covers a wide range, from work on the nearest stars to studies of the distant quasars, and the astronomers who have carried out this work come from universities and observatories spread around the world as well as from South African universities and from the South African Astronomical Observatory (SAAO) staff itself. A characteristic of much of this work has been its collaborative character. SAAO studies in 1989 included: supernovae 1987A; galaxies; ground-based observations of celestial x-ray sources; the Magellanic Clouds; pulsating variables; galactic structure; binary star phenomena; the provision of photometric standards; nebulous matter; stellar astrophysics, and astrometry

  3. Laboratory Experiments to Simulate and Investigate the Physics Underlying the Dynamics of Merging Solar Corona Structures

    Science.gov (United States)

    2016-06-05

    efficiently by using current density rather than electric field as the fundamental wave quantity. 3. Moser & Bellan (2012) showed that the effective gravity...there is effectively a magnetic bubble. This is relevant to interplanetary magnetic clouds spawned by the eruptions of solar corona structures. 10...release. Haw, Magnus , & Bellan, Paul. 2015. 1D fast coded aperture camera. Review of Scientific Instruments, 86(4). 043506. Moser, Auna L., & Bellan

  4. Dynamical response of the magnetotail to changes of the solar wind direction: an MHD modeling perspective

    Directory of Open Access Journals (Sweden)

    V. A. Sergeev

    2008-08-01

    Full Text Available We performed global MHD simulations to investigate the magnetotail response to the solar wind directional changes (Vz-variations. These changes, although small, cause significant variations of the neutral sheet shape and location even in the near and middle tail regions. They display a complicated temporal response, in which ~60 to 80% of the final shift of the neutral sheet in Z direction occurs within first 10–15 min (less for faster solar wind, whereas a much longer time (exceeding half hour is required to reach a new equilibrium. The asymptotic equilibrium shape of the simulated neutral sheet is consistent with predictions of Tsyganenko-Fairfield (2004 empirical model. To visualize a physical origin of the north-south tail motion we compared the values of the total pressure in the northern and southern tail lobes and found a considerable difference (10–15% for only 6° change of the solar wind direction used in the simulation. That difference builds up during the passage of the solar wind directional discontinuity and is responsible for the vertical shift of the neutral sheet, although some pressure difference remains in the near tail even near the new equilibrium. Surprisingly, at a given tailward distance, the response was found to be first initiated in the tail center (the "leader effect", rather than near the flanks, which can be explained by the wave propagation in the tail, and which may have interesting implications for the substorm triggering studies. The present results have serious implications for the data-based modeling, as they place constraints on the accuracy of tail magnetic configurations to be derived for specific events using data of multi-spacecraft missions, e.g. such as THEMIS.

  5. Dynamic and optical characterization of dusty plasmas for use as solar sails

    International Nuclear Information System (INIS)

    Sheldon, Robert; Thomas, Edward Jr.; Abbas, Mian; Gallagher, Dennis; Adrian, Mark; Craven, Paul

    2002-01-01

    Solar sails presently have mass loadings of 5 gm/m2 that, when including the support structure and payload, could easily average to >10 gm/m2. For reasonably sized spacecraft, the critical parameter is the total mass per total area, which when combined with the reflectivity, yield the true acceleration. We propose that dusty plasmas trapped in a 'Mini-Magnetosphere' (Winglee, 2000) can produce a solar sail with a total mass loading <0.01 gm/m2, and reflectivities of ∼1%. This configuration provides an acceleration equivalent to a standard sail of 95% reflectivity with <1 gm/m2. However, the physics of dusty plasma sails is not mature and several important questions need to be resolved before a large scale effort is warranted. Foremost among these questions are, what is the largest force a dusty plasma can sustain before it demagnetizes and separates from the binding magnetic field; what are the charging properties of dust under solar UV conditions; what is the light scattering cross section for the dust; what is the optimum dust grain size for magnetization and scattering; and, what are the optimum dust grain materials? We outline what we know about dusty plasmas, and what we are hoping to learn from two existing dusty plasma experiments at the National Space Science and Technology Center (NSSTC) and Auburn University

  6. Improvements in geomagnetic observatory data quality

    DEFF Research Database (Denmark)

    Reda, Jan; Fouassier, Danielle; Isac, Anca

    2011-01-01

    between observatories and the establishment of observatory networks has harmonized standards and practices across the world; improving the quality of the data product available to the user. Nonetheless, operating a highquality geomagnetic observatory is non-trivial. This article gives a record...... of the current state of observatory instrumentation and methods, citing some of the general problems in the complex operation of geomagnetic observatories. It further gives an overview of recent improvements of observatory data quality based on presentation during 11th IAGA Assembly at Sopron and INTERMAGNET...

  7. Reduced-Order Dynamic Modeling, Fouling Detection, and Optimal Control of Solar-Powered Direct Contact Membrane Distillation

    KAUST Repository

    Karam, Ayman M.

    2016-12-01

    Membrane Distillation (MD) is an emerging sustainable desalination technique. While MD has many advantages and can be powered by solar thermal energy, its main drawback is the low water production rate. However, the MD process has not been fully optimized in terms of its manipulated and controlled variables. This is largely due to the lack of adequate dynamic models to study and simulate the process. In addition, MD is prone to membrane fouling, which is a fault that degrades the performance of the MD process. This work has three contributions to address these challenges. First, we derive a mathematical model of Direct Contact Membrane Distillation (DCMD), which is the building block for the next parts. Then, the proposed model is extended to account for membrane fouling and an observer-based fouling detection method is developed. Finally, various control strategies are implemented to optimize the performance of the DCMD solar-powered process. In part one, a reduced-order dynamic model of DCMD is developed based on lumped capacitance method and electrical analogy to thermal systems. The result is an electrical equivalent thermal network to the DCMD process, which is modeled by a system of nonlinear differential algebraic equations (DAEs). This model predicts the water-vapor flux and the temperature distribution along the module length. Experimental data is collected to validate the steady-state and dynamic responses of the proposed model, with great agreement demonstrated in both. The second part proposes an extension of the model to account for membrane fouling. An adaptive observer for DAE systems is developed and convergence proof is presented. A method for membrane fouling detection is then proposed based on adaptive observers. Simulation results demonstrate the performance of the membrane fouling detection method. Finally, an optimization problem is formulated to maximize the process efficiency of a solar-powered DCMD. The adapted method is known as Extremum

  8. Low-frequency Radio Observatory on the Lunar Surface (LROLS)

    Science.gov (United States)

    MacDowall, Robert; Network for Exploration and Space Science (NESS)

    2018-06-01

    A radio observatory on the lunar surface will provide the capability to image solar radio bursts and other sources. Radio burst imaging will improve understanding of radio burst mechanisms, particle acceleration, and space weather. Low-frequency observations (less than ~20 MHz) must be made from space, because lower frequencies are blocked by Earth’s ionosphere. Solar radio observations do not mandate an observatory on the farside of the Moon, although such a location would permit study of less intense solar bursts because the Moon occults the terrestrial radio frequency interference. The components of the lunar radio observatory array are: the antenna system consisting of 10 – 100 antennas distributed over a square kilometer or more; the system to transfer the radio signals from the antennas to the central processing unit; electronics to digitize the signals and possibly to calculate correlations; storage for the data until it is down-linked to Earth. Such transmission requires amplification and a high-gain antenna system or possibly laser comm. For observatories on the lunar farside a satellite or other intermediate transfer system is required to direct the signal to Earth. On the ground, the aperture synthesis analysis is completed to display the radio image as a function of time. Other requirements for lunar surface systems include the power supply, utilizing solar arrays with batteries to maintain the system at adequate thermal levels during the lunar night. An alternative would be a radioisotope thermoelectric generator requiring less mass. The individual antennas might be designed with their own solar arrays and electronics to transmit data to the central processing unit, but surviving lunar night would be a challenge. Harnesses for power and data transfer from the central processing unit to the antennas are an alternative, but a harness-based system complicates deployment. The concept of placing the antennas and harnesses on rolls of polyimide and

  9. Deep Space Climate Observatory (DSCOVR)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Deep Space Climate ObserVatoRy (DSCOVR) satellite is a NOAA operated asset at the first Lagrange (L1) point. The primary space weather instrument is the PlasMag...

  10. Solar Imagery - GONG (H-alpha)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Oscillation Network Group (GONG) is a network of 6 globally-spaced solar observatories that the NOAA Space Weather Prediction Center uses to monitor the...

  11. Seafloor Observatory Science: a Review

    Directory of Open Access Journals (Sweden)

    L. Beranzoli

    2006-06-01

    Full Text Available The ocean exerts a pervasive influence on Earth’s environment. It is therefore important that we learn how this system operates (NRC, 1998b; 1999. For example, the ocean is an important regulator of climate change (e.g., IPCC, 1995. Understanding the link between natural and anthropogenic climate change and ocean circulation is essential for predicting the magnitude and impact of future changes in Earth’s climate. Understanding the ocean, and the complex physical, biological, chemical, and geological systems operating within it, should be an important goal for the opening decades of the 21st century. Another fundamental reason for increasing our understanding of ocean systems is that the global economy is highly dependent on the ocean (e.g., for tourism, fisheries, hydrocarbons, and mineral resources (Summerhayes, 1996. The establishment of a global network of seafloor observatories will help to provide the means to accomplish this goal. These observatories will have power and communication capabilities and will provide support for spatially distributed sensing systems and mobile platforms. Sensors and instruments will potentially collect data from above the air-sea interface to below the seafloor. Seafloor observatories will also be a powerful complement to satellite measurement systems by providing the ability to collect vertically distributed measurements within the water column for use with the spatial measurements acquired by satellites while also providing the capability to calibrate remotely sensed satellite measurements (NRC, 2000. Ocean observatory science has already had major successes. For example the TAO array has enabled the detection, understanding and prediction of El Niño events (e.g., Fujimoto et al., 2003. This paper is a world-wide review of the new emerging “Seafloor Observatory Science”, and describes both the scientific motivations for seafloor observatories and the technical solutions applied to their architecture. A

  12. Design and dynamic simulation of a novel solar trigeneration system based on hybrid photovoltaic/thermal collectors (PVT)

    International Nuclear Information System (INIS)

    Calise, Francesco; D’Accadia, Massimo Dentice; Vanoli, Laura

    2012-01-01

    Highlights: ► Sheet and tube photovoltaic/thermal (PVT) solar collector are investigated. ► PVT is integrated in a novel solar trigeneration system. ► The trigeneration system is dynamically investigated for a mediterranean climate. ► PVT performance is excellent during the summer. ► During the winter PVT thermal energy significantly decreases. - Abstract: In this paper, a Solar Heating and Cooling (SHC) system including photovoltaic/thermal (PVT) collectors is considered, implementing a novel polygeneration system producing electricity, space heating and cooling and domestic hot water. In particular, PVT collectors operating up to 80 °C are considered. A case study for a university building located in Naples (Italy) is developed and discussed. The system is mainly composed by: PVT collectors, a single-stage LiBr–H 2 O absorption chiller, storage tanks and auxiliary heaters. The system also includes additional balance-of-plant devices: heat exchangers, pumps, controllers, cooling tower, etc. The PVT produces electricity which is utilized in part by the building lights and equipments and in part by the system parasitic loads; the rest is eventually sold to the grid. Simultaneously, the PVT system provides the heat required to drive the absorption chiller. The system performance is analyzed from both energetic and economic points of view by means of a zero-dimensional transient simulation model, developed with TRNSYS. The economic results show that the system under investigation can be profitable, provided that an appropriate funding policy is available. In addition, the overall energetic and economic results are comparable to those reported in literature for similar systems.

  13. Design and dynamic simulation of a novel polygeneration system fed by vegetable oil and by solar energy

    International Nuclear Information System (INIS)

    Calise, Francesco; Palombo, Adolfo; Vanoli, Laura

    2012-01-01

    Highlights: ► A novel polygeneration system based on engines (RE) fed by rapeseed oil is investigated. ► RE are integrated with high temperature solar heating and cooling systems. ► The polygeneration system is dynamically investigated for a Mediterranean Climate. ► System performance is excellent from the energetic point of view. ► The system is economically profitable only in case of feed-in tariffs. - Abstract: In this paper the integration of vegetable oil-fed reciprocating engines with solar thermal collector is investigated, seeking to design a novel polygeneration system producing: electricity, space heating and cooling and domestic hot water, for a university building located in Naples (Italy), assumed as case study. The polygeneration system is based on the following main components: concentrating parabolic trough solar collector, double-stage LiBr–H 2 O absorption chiller and a reciprocating engine fed by vegetable oil. The engine operates at full load producing electrical energy which is in part consumed by the building lights and equipments, in part used by the system passive loads and the rest is eventually sold to the grid. In fact, the engine is grid connected in order to perform a convenient net metering. The system was designed and then simulated by means of a zero-dimensional transient simulation model, developed using the TRNSYS software. The simulation tool developed by the authors allows one to analyze the results for different time basis (minutes, days, weeks, months and years), from both energetic and economic points of view. The economic results show that the system under investigation is profitable, especially if properly funded.

  14. Dynamic evolution of the source volumes of gradual and impulsive solar flare emissions

    Science.gov (United States)

    Bruner, M. E.; Crannell, C. J.; Goetz, F.; Magun, A.; Mckenzie, D. L.

    1988-01-01

    This study compares flare source volumes inferred from impulsive hard X-rays and microwaves with those derived from density sensitive soft X-ray line ratios in the O VII spectrum. The data for this study were obtained with the SMM Hard X-ray Burst Spectrometer, Earth-based radio observatories, and the SOLEX-B spectrometer on the P78-1 satellite. Data were available for the flares of 1980 April 8, 1980 May 9, and 1981 February 26. The hard X-ray/microwave source volume is determined under the assumption that the same electron temperature or power law index characterizes both the source of hard X-rays and the source of microwaves. The O VII line ratios yield the density and volume of the 2 x 10 to the 6th K plasma. For all three flares, the O VII source volume is found to be smallest at the beginning of the flare, near the time when the impulsive hard X-ray/microwave volume reaches its first maximum. At this time, the O VII volume is three to four orders of magnitude smaller than that inferred from the hard X-ray/microwave analysis. Subsequently, the O VII source volume increases by one or two orders of magnitude then remains almost constant until the end of the flare when it apparently increases again.

  15. Dynamic evolution of the source volumes of gradual and impulsive solar flare emissions

    International Nuclear Information System (INIS)

    Bruner, M.E.; Crannell, C.J.; Goetz, F.; Magun, A.; Mckenzie, D.L.

    1987-12-01

    This study compares flare source volumes inferred from impulsive hard x rays and microwaves with those derived from density sensitive soft x ray line ratios in the O VII spectrum. The data for this study were obtained with the SMM Hard X-Ray Burst Spectrometer, Earth-based radio observatories, and the SOLEX-B spectrometer on the P78-1 satellite. Data were available for the flares of 1980 April 8, 1980 May 9, and 1981 February 26. The hard x ray/microwave source volume is determined under the assumption that the same electron temperature or power law index characterizes both the source of hard x rays and the source of microwaves. The O VII line ratios yield the density and volume of the 2 X 10 to the 6th K plasma. For all three flares, the O VII source volume is found to be smallest at the beginning of the flare, near the time when the impulsive hard x ray/microwave volume reaches its first maximum. At this time, the O VII volume is three to four orders of magnitude smaller than that inferred from the hard x ray/microwave analysis. Subsequently, the O VII source volume increases by one or two orders of magnitude then remains almost constant until the end of the flare when it apparently increases again

  16. Dynamic evolution of the source volumes of gradual and impulsive solar flare emissions

    International Nuclear Information System (INIS)

    Bruner, M.E.; Crannell, C.J.; Goetz, F.; Magun, A.; Mckenzie, D.L.

    1988-01-01

    This study compares flare source volumes inferred from impulsive hard X-rays and microwaves with those derived from density sensitive soft X-ray line ratios in the O VII spectrum. The data for this study were obtained with the SMM Hard X-ray Burst Spectrometer, Earth-based radio observatories, and the SOLEX-B spectrometer on the P78-1 satellite. Data were available for the flares of 1980 April 8, 1980 May 9, and 1981 February 26. The hard X-ray/microwave source volume is determined under the assumption that the same electron temperature or power law index characterizes both the source of hard X-rays and the source of microwaves. The O VII line ratios yield the density and volume of the 2 x 10 to the 6th K plasma. For all three flares, the O VII source volume is found to be smallest at the beginning of the flare, near the time when the impulsive hard X-ray/microwave volume reaches its first maximum. At this time, the O VII volume is three to four orders of magnitude smaller than that inferred from the hard X-ray/microwave analysis. Subsequently, the O VII source volume increases by one or two orders of magnitude then remains almost constant until the end of the flare when it apparently increases again. 29 references

  17. Response of the mesopause airglow to solar activity inferred from measurements at Zvenigorod, Russia

    Directory of Open Access Journals (Sweden)

    N. Pertsev

    2008-05-01

    Full Text Available Ground-based spectrographical observations of infrared emissions of the mesopause region have been made at Zvenigorod Observatory (56 N, 37 E, located near Moscow, Russia, for 670 nights of 2000–2006. The characteristics of the hydroxyl and molecular oxygen (865 nm airglow, heights of which correspond to 87 and 94 km, are analyzed for finding their response to solar activity. The measured data exhibit a response to the F10.7 solar radio flux change, which is 30%–40%/100 sfu in intensities of the emissions and about 4.5 K/100 sfu in hydroxyl temperature. Seasonal variations of the airglow response to solar activity are observed. In winter it is more significant than in summer. Mechanisms that may provide an explanation of the solar influence on intensities of the emissions and temperature are considered. Radiative processes not involving atmospheric dynamics appear insufficient to explain the observed effect.

  18. Response of the mesopause airglow to solar activity inferred from measurements at Zvenigorod, Russia

    Directory of Open Access Journals (Sweden)

    N. Pertsev

    2008-05-01

    Full Text Available Ground-based spectrographical observations of infrared emissions of the mesopause region have been made at Zvenigorod Observatory (56 N, 37 E, located near Moscow, Russia, for 670 nights of 2000–2006. The characteristics of the hydroxyl and molecular oxygen (865 nm airglow, heights of which correspond to 87 and 94 km, are analyzed for finding their response to solar activity. The measured data exhibit a response to the F10.7 solar radio flux change, which is 30%–40%/100 sfu in intensities of the emissions and about 4.5 K/100 sfu in hydroxyl temperature. Seasonal variations of the airglow response to solar activity are observed. In winter it is more significant than in summer. Mechanisms that may provide an explanation of the solar influence on intensities of the emissions and temperature are considered. Radiative processes not involving atmospheric dynamics appear insufficient to explain the observed effect.

  19. Electricity and gas market observatory. 2. quarter 2007

    International Nuclear Information System (INIS)

    2007-01-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web-site (www.cre.fr). It presents: The electricity market; The retail electricity market: Non-residential customer segments and their respective weights, Status at July 1, 2007, Dynamic analysis: 2. Quarter 2007; The wholesale electricity market: Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the second quarter 2007; The gas market; The retail gas market: The non-residential customer segments and their respective weights, Status at July 1. 2007; The wholesale gas market: Gas pricing and gas markets in Europe,The wholesale market in France. Some glossaries are attached to the document: Electricity and gas market observatories combined glossary; Specific electricity market observatory glossary; Specific gas market observatory glossary

  20. Electricity and gas market observatory. 1. Quarter 2007

    International Nuclear Information System (INIS)

    2007-01-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). It completes the information already published by CRE: - practical information for eligible customers: consumer guide, list of suppliers, - communications regarding markets running; CRE's annual activity report. Content: A - The electricity market: The retail electricity market (Introduction, Eligible customer segments and their respective weights, Status at April 1, 2007, Dynamic analysis: 1. Quarter 2007); The wholesale electricity market (Introduction, Traded volumes on the French wholesale electricity market and comparison with European markets, Prices on the French wholesale electricity market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the 1. 2007 quarter); B - The gas market: The retail gas market (Introduction, The eligible customer segments and their respective weights, Status at April 1, 2007); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  1. Electricity and gas market observatory. 4. Quarter 2006

    International Nuclear Information System (INIS)

    2006-01-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web site (www.cre.fr). It completes the information already published by CRE: - practical information for eligible customers: consumer guide, list of suppliers, - communications regarding markets running; CRE's annual activity report. Content: A - The electricity market: The retail electricity market (Introduction, Eligible customer segments and their respective weights, Status at January 1, 2007, Dynamic analysis: 4. Quarter 2006); The wholesale electricity market (Introduction, Traded volumes on the French wholesale electricity market and comparison with European markets, Prices on the French wholesale electricity market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the 4. 2006 quarter); B - The gas market: The retail gas market (Introduction, The eligible customer segments and their respective weights, Status at January 1, 2007); The wholesale gas market (Gas pricing and gas markets in Europe, The wholesale market in France); C - Appendices: Electricity and gas market observatories combined glossary, Specific electricity market observatory glossary, Specific gas market observatory glossary

  2. Electricity and gas market observatory. 1. quarter 2007

    International Nuclear Information System (INIS)

    2007-01-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web-site (www.cre.fr). It presents: The electricity market; The retail electricity market: Eligible customer segments and their respective weights, Status at April 1, 2007, Dynamic analysis: 1. Quarter 2007; The wholesale electricity market: Traded volumes on the French wholesale electricity market and comparison with European markets, Prices on the French wholesale electricity market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the 1. 2007 quarter; The gas market; The retail gas market: The eligible customer segments and their respective weights, Status at April 1. 2007; The wholesale gas market: Gas pricing and gas markets in Europe,The wholesale market in France. Some glossaries are attached to the document: Electricity and gas market observatories combined glossary; Specific electricity market observatory glossary; Specific gas market observatory glossary

  3. Electricity and gas market observatory. 4. quarter 2006

    International Nuclear Information System (INIS)

    2007-01-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web-site (www.cre.fr). It presents: The electricity market; The retail electricity market: Eligible customer segments and their respective weights, Status at January 1, 2007, Dynamic analysis: 4. Quarter 2007; The wholesale electricity market: Traded volumes on the French wholesale electricity market and comparison with European markets, Prices on the French wholesale electricity market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the 4. 2006 quarter; The gas market; The retail gas market: The eligible customer segments and their respective weights, Status at January 1. 2007; The wholesale gas market: Gas pricing and gas markets in Europe,The wholesale market in France. Some glossaries are attached to the document: Electricity and gas market observatories combined glossary; Specific electricity market observatory glossary; Specific gas market observatory glossary

  4. Electricity and gas market observatory. 2. quarter 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web-site (www.cre.fr). It presents: The electricity market; The retail electricity market: Non-residential customer segments and their respective weights, Status at July 1, 2007, Dynamic analysis: 2. Quarter 2007; The wholesale electricity market: Wholesale market activity in France, Prices on the French wholesale market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the second quarter 2007; The gas market; The retail gas market: The non-residential customer segments and their respective weights, Status at July 1. 2007; The wholesale gas market: Gas pricing and gas markets in Europe,The wholesale market in France. Some glossaries are attached to the document: Electricity and gas market observatories combined glossary; Specific electricity market observatory glossary; Specific gas market observatory glossary.

  5. Electricity and gas market observatory. 1. quarter 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web-site (www.cre.fr). It presents: The electricity market; The retail electricity market: Eligible customer segments and their respective weights, Status at April 1, 2007, Dynamic analysis: 1. Quarter 2007; The wholesale electricity market: Traded volumes on the French wholesale electricity market and comparison with European markets, Prices on the French wholesale electricity market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the 1. 2007 quarter; The gas market; The retail gas market: The eligible customer segments and their respective weights, Status at April 1. 2007; The wholesale gas market: Gas pricing and gas markets in Europe,The wholesale market in France. Some glossaries are attached to the document: Electricity and gas market observatories combined glossary; Specific electricity market observatory glossary; Specific gas market observatory glossary.

  6. Electricity and gas market observatory. 4. quarter 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Since July 1, 2004, all electricity and gas consumers can be eligible according to their consumption site, as long as all or part of the electricity or gas consumed is designed for non-residential use. The purpose of the observatory is to provide the general public with indicators for monitoring market deregulation. It both covers the wholesale and retail electricity and gas markets in Metropolitan France. This observatory is updated every three months and data are available on CRE web-site (www.cre.fr). It presents: The electricity market; The retail electricity market: Eligible customer segments and their respective weights, Status at January 1, 2007, Dynamic analysis: 4. Quarter 2007; The wholesale electricity market: Traded volumes on the French wholesale electricity market and comparison with European markets, Prices on the French wholesale electricity market and European comparison, Import and export volumes, Concentration of the French electricity market, Striking facts of the 4. 2006 quarter; The gas market; The retail gas market: The eligible customer segments and their respective weights, Status at January 1. 2007; The wholesale gas market: Gas pricing and gas markets in Europe,The wholesale market in France. Some glossaries are attached to the document: Electricity and gas market observatories combined glossary; Specific electricity market observatory glossary; Specific gas market observatory glossary.

  7. Norwegian Ocean Observatory Network (NOON)

    Science.gov (United States)

    Ferré, Bénédicte; Mienert, Jürgen; Winther, Svein; Hageberg, Anne; Rune Godoe, Olav; Partners, Noon

    2010-05-01

    The Norwegian Ocean Observatory Network (NOON) is led by the University of Tromsø and collaborates with the Universities of Oslo and Bergen, UniResearch, Institute of Marine Research, Christian Michelsen Research and SINTEF. It is supported by the Research Council of Norway and oil and gas (O&G) industries like Statoil to develop science, technology and new educational programs. Main topics relate to ocean climate and environment as well as marine resources offshore Norway from the northern North Atlantic to the Arctic Ocean. NOON's vision is to bring Norway to the international forefront in using cable based ocean observatory technology for marine science and management, by establishing an infrastructure that enables real-time and long term monitoring of processes and interactions between hydrosphere, geosphere and biosphere. This activity is in concert with the EU funded European Strategy Forum on Research Infrastructures (ESFRI) roadmap and European Multidisciplinary Seafloor Observation (EMSO) project to attract international leading research developments. NOON envisions developing towards a European Research Infrastructure Consortium (ERIC). Beside, the research community in Norway already possesses a considerable marine infrastructure that can expand towards an international focus for real-time multidisciplinary observations in times of rapid climate change. PIC The presently established cable-based fjord observatory, followed by the establishment of a cable-based ocean observatory network towards the Arctic from an O&G installation, will provide invaluable knowledge and experience necessary to make a successful larger cable-based observatory network at the Norwegian and Arctic margin (figure 1). Access to large quantities of real-time observation from the deep sea, including high definition video, could be used to provide the public and future recruits to science a fascinating insight into an almost unexplored part of the Earth beyond the Arctic Circle

  8. Solar Flare Five-Day Predictions from Quantum Detectors of Dynamical Space Fractal Flow Turbulence: Gravitational Wave Diminution and Earth Climate Cooling