WorldWideScience

Sample records for sun solar center

  1. The Sun: A Star at the Center of Our Solar System

    Science.gov (United States)

    Adams, Mitzi L.

    2016-01-01

    There is a star at the center of our solar system! But what is a star? How do stars work? What are the characteristics of our Sun and how are these traits different from other stars? How does the Sun compare to stars such as Betelgeuse and Rigel? "Will the Sun end its life with a bang or a whimper?"

  2. Solar flare leaves sun quaking

    Science.gov (United States)

    1998-05-01

    energy, and produce X-rays, microwaves and a shock wave that heats the solar surface. Kosovichev and Zharkova developed a theory that predicts the nature and magnitude of the shock waves that this beam of energetic electrons should create when they slam down into the solar atmosphere. Although their theory directed them to the right area to search for the seismic waves, the waves that they found were 10 times stronger than they had predicted. "They were so strong that you can see them in the raw data," Kosovichev says. The solar seismic waves appear to be compression waves like the "P" waves generated by an earthquake. They travel throughout the Sun's interior. In fact, the waves should recombine on the opposite side of the Sun from the location of the flare to create a faint duplicate of the original ripple pattern, Kosovichev predicts. Now that they know how to find them, the SOHO scientists say that the seismic waves generated by solar flares should allow them to verify independently some of the conditions in the solar interior that they have inferred from studying the pattern of waves that are continually ruffling the Sun's surface. SOHO is part of the International Solar-Terrestrial Physics (ISTP) program, a global effort to observe and understand our star and its effects on our environment. The ISTP mission includes more than 20 satellites, coupled with with ground-based observatories and modeling centers, that allow scientists to study the Sun, the Earth, and the space between them in unprecedented detail. ISTP is a joint program of NASA, ESA, Japan's Institute for Astronautical Science, and Russia's Space Research Institute. Still images of the solar quake can be found at the following internet address: FTP://PAO.GSFC.NASA.GOV/newsmedia/QUAKE/ For further information, please contact : ESA Public Relations Division Tel:+33(0)1.53.69.71.55 Fax: +33(0)1.53.69.76.90 3

  3. The Sun Rises on the Solar Sector

    OpenAIRE

    Ahmad, Reyaz A.

    2009-01-01

    Energy from the sun is abundant and free. Solar energy is in essence electromagnetic radiation emitted from the sun. Earth's climate, hydrologic systems, and ecosystems all derive from the sun. Other forms of renewable power such as wind, wave, biomass, and hydro are an indirect function of solar radiation.

  4. SunPy—Python for solar physics

    Science.gov (United States)

    SunPy Community; Mumford, Stuart J.; Christe, Steven; Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew R.; Liedtke, Simon; Hewett, Russell J.; Mayer, Florian; Hughitt, Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M.; Malocha, Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J.; Robitaille, Thomas P.; Mampaey, Benjamin; Campos-Rozo, Jose Iván; Kirk, Michael S.

    2015-01-01

    This paper presents SunPy (version 0.5), a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation (NumPy, SciPy) and machine learning (scikit-learn) to visualization and plotting (matplotlib). SunPy is a data-analysis environment specializing in providing the software necessary to analyse solar and heliospheric data in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from missions such as GOES, SDO/EVE, and PROBA2/LYRA, and radio spectra from e-Callisto and STEREO/SWAVES. We describe SunPy's functionality, provide examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  5. SunPy: Solar Physics in Python

    Science.gov (United States)

    Ryan, Daniel; Christe, Steven; Mumford, Stuart; Perez Suarez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon; Hewett, Russel

    2015-04-01

    SunPy is a community-developed open-source software library for solar physics. It is written in Python, a free, cross-platform, general-purpose, high-level programming language which is being increasingly adopted throughout the scientific community as well as further afield. This has resulted in a wide array of software packages useful for scientific computing, from numerical computation (NumPy, SciPy, etc.), to machine learning (scifitlearn), to visualization and plotting (matplotlib). SunPy aims to provide required specialised software for analysing solar and heliospheric datasets in Python. The current version is 0.5 with 0.6 expected to be released later this year. SunPy provides solar data access through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It supports common data types from major solar missions such as images (SDO/AIA, STEREO, PROBA2/SWAP etc.), time series (GOES/XRS, SDO/EVE, PROBA2/LYRA), and radio spectra (e-Callisto, STEREO/WAVES). SunPy’s code base is publicly available through github.com and can be contributed to by anyone. In this poster we demonstrate SunPy’s functionality and future goals of the project. We also encourage interested users to become involved in further developing SunPy.

  6. The sun and heliosphere at solar maximum.

    Science.gov (United States)

    Smith, E J; Marsden, R G; Balogh, A; Gloeckler, G; Geiss, J; McComas, D J; McKibben, R B; MacDowall, R J; Lanzerotti, L J; Krupp, N; Krueger, H; Landgraf, M

    2003-11-14

    Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.

  7. Optimal control of sun tracking solar concentrators

    Science.gov (United States)

    Hughes, R. O.

    1979-01-01

    Application of the modern control theory to derive an optimal sun tracking control for a point focusing solar concentrator is presented. A standard tracking problem converted to regulator problem using a sun rate input achieves an almost zero steady state tracking error with the optimal control formulation. However, these control techniques are costly because optimal type algorithms require large computing systems, thus they will be used mainly as comparison standards for other types of control algorithms and help in their development.

  8. SunPy - Python for Solar Physics

    CERN Document Server

    Community, The SunPy; Christe, Steven; Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y; Inglis, Andrew R; Liedtke, Simon; Hewett, Russell J; Mayer, Florian; Hughitt, Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M; Malocha, Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J; Robitaille, Thomas P; Mampaey, Benjamin; Campos-Rozo, Jose Iván; Kirk, Michael S

    2015-01-01

    This paper presents SunPy (version 0.5), a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation (NumPy, SciPy) and machine learning (scikit-learn) to visualisation and plotting (matplotlib). SunPy is a data-analysis environment specialising in providing the software necessary to analyse solar and heliospheric data in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from mis...

  9. The Sun's interior structure and dynamics, and the solar cycle

    CERN Document Server

    Broomhall, A -M; Howe, R; Norton, A A; Thompson, M J

    2014-01-01

    The Sun's internal structure and dynamics can be studied with helioseismology, which uses the Sun's natural acoustic oscillations to build up a profile of the solar interior. We discuss how solar acoustic oscillations are affected by the Sun's magnetic field. Careful observations of these effects can be inverted to determine the variations in the structure and dynamics of the Sun's interior as the solar cycle progresses. Observed variations in the structure and dynamics can then be used to inform models of the solar dynamo, which are crucial to our understanding of how the Sun's magnetic field is generated and maintained.

  10. Reading The Sun: A Three Dimensional Visual Model of The Solar Environment During Solar Cycle 24

    Science.gov (United States)

    Carranza-fulmer, T. L.; Moldwin, M.

    2014-12-01

    The sun is a powerful force that has proven to our society that it has a large impact on our lives. Unfortunately, there is still a lack of awareness on how the sun is capable of affecting Earth. The over all idea of "Reading The Sun" installation is to help demonstrate how the sun impacts the Earth, by compiling various data sources from satellites (SOHO, SDO, and STERO) with solar and solar wind models (MAS and ENLIL) to create a comprehensive three dimensional display of the solar environment. It focuses on the current solar maximum of solar cycle 24 and a CME that impacted Earth's magnetic field on February 27, 2014, which triggered geomagnetic storms around the Earth's poles. The CME was an after-effect of a class X4.9 solar flare, which was released from the sun on February 25, 2014. "Reading The Sun" is a 48" x 48" x 48" hanging model of the sun with color coded open opposing magnetic field lines along with various layers of the solar atmosphere, the heliospheric current sheet, and the inner planets. At the center of the xyz axis is the sun with the open magnetic field lines and the heliospheric current sheet permeating inner planetary space. The xyz axes are color coded to represent various types of information with corresponding visual images for the viewer to be able to read the model. Along the z-axis are three colors (yellow, orange, and green) that represent the different layers of the solar atmosphere (photosphere, chromosphere, and corona) that correspond to three satellite images in various spectrums related to a CME and Solar Flare and the xy-plane shows where the inner planets are in relation to the sun. The exhibit in which "Reading The Sun "is being displayed is called, The Rotation of Language at the Wheather Again Gallery in Rockaway, New York. The intent of the exhibit is to both celebrate as well as present a cautionary tale on the ability of human language to spark and ignite the individual and collective imagination towards an experience

  11. Solar winds surfs waves in the Sun's atmosphere!

    Science.gov (United States)

    1999-07-01

    opposite ends after threading it through an object, like a ring. If one person wiggles the string rapidly up and down, waves form in the string that move toward the person at the other end. The ring will "surf" these waves and move toward the other person as well. Try it! "Even with this major discovery, there are questions left to answer. The observations have made it abundantly clear that heavy particles like oxygen 'surf' on the waves, and there is also mounting evidence that waves are responsible for accelerating the hydrogen atoms, the most common constituent of the solar wind. Future observations are needed to establish this fact. Many other kinds of particles, such as helium (second most common) have never been observed in the accelerating part of the corona, and new observations are also needed to refine our understanding of how the waves interact with the solar wind as a whole," said Dr. Steven Cranmer of the Harvard-Smithsonian Center for Astrophysics, lead author of the research to be published in the Astrophysical Journal*. Nevertheless, SOHO has again been able to reveal another of the Sun's mysteries: "This is another triumph for SOHO, stealing a long-held secret from our Sun", said Dr Martin Huber, Head of ESA Space Science Department and co-investigator for UVCS. *Ref. Article by S.Cranmer, G.B. Field and J.L. Kohl on Astrophysical Journal ( June 20, Vol 518, p. 937-947) available on the web at: http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v518n2/39802/sc0.html

  12. Drift-free solar sail formations in elliptical Sun-synchronous orbits

    Science.gov (United States)

    Parsay, Khashayar; Schaub, Hanspeter

    2017-10-01

    To study the spatial and temporal variations of plasma in the highly dynamic environment of the magnetosphere, multiple spacecraft must fly in a formation. The objective for this study is to investigate the feasibility of solar sail formation flying in the Earth-centered, Sun-synchronous orbit regime. The focus of this effort is to enable formation flying for a group of solar sails that maintain a nominally fixed Sun-pointing attitude during formation flight, solely for the purpose of precessing their orbit apse lines Sun-synchronously. A fixed-attitude solar sail formation is motivated by the difficulties in the simultaneous control of orbit and attitude in flying solar sails. First, the secular rates of the orbital elements resulting from the effects of solar radiation pressure (SRP) are determined using averaging theory for a Sun-pointing attitude sail. These averaged rates are used to analytically derive the first-order necessary conditions for a drift-free solar sail formation in Sun-synchronous orbits, assuming a fixed Sun-pointing orientation for each sail in formation. The validity of the first-order necessary conditions are illustrated by designing quasi-periodic relative motions. Next, nonlinear programming is applied to design truly drift-free two-craft solar sail formations. Lastly, analytic expressions are derived to determine the long-term dynamics and sensitivity of the formation with respect to constant attitude errors, uncertainty in orbital elements, and uncertainty in a sail's characteristic acceleration.

  13. Solar Energy Education. Reader, Part II. Sun story. [Includes glossary

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    Magazine articles which focus on the subject of solar energy are presented. The booklet prepared is the second of a four part series of the Solar Energy Reader. Excerpts from the magazines include the history of solar energy, mythology and tales, and selected poetry on the sun. A glossary of energy related terms is included. (BCS)

  14. Science Experimenter: Observing the Sun and Solar Eclipses.

    Science.gov (United States)

    Mims, Forrest M., III

    1991-01-01

    Describes the construction and use of simple optical aids that allow the amateur scientist to safely observe sunspots and solar eclipses and also to measure the sun's rotation. (five references) (JJK)

  15. Thermal evaluation of a sun tracking solar cooker

    Directory of Open Access Journals (Sweden)

    Yousif El-Tous, Omar. O. Badran, Anwar Al-Mofleh

    2012-01-01

    Full Text Available Solar energy is one of many important types of renewable energy. Jordan is of great needs for renewable energy systems applications since it depends totally in generation of its required energy on imported oil. This study is an experimental work of tracking system developed for enhancing the solar heating using solar cooker. An electronic sun tracking device was used for rotating the solar heater with the movement of the sun. A comparison between fixed and sun tracked cooker showed that the use of sun tracking increased the heating temperature by 36% due to the increase in radiation concentration and using internal mirror reflectors. The programming method used for tracking control works efficiently in all weather conditions regardless of the presence of clouds. It can be used as backup control circuit in which relays are the essential control devices.

  16. Solar Energy Education. Reader, Part IV. Sun schooling

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    A collection of magazine articles which focus on solar energy is presented. This is the final book of the four part series of the Solar Energy Reader. The articles include brief discussions on energy topics such as the sun, ocean energy, methane gas from cow manure, and solar homes. Instructions for constructing a sundial and a solar stove are also included. A glossary of energy related terms is provided. (BCS)

  17. Photometric Variations In The Sun And Solar-Type Stars

    Science.gov (United States)

    Giampapa, Mark

    The rich array of solar magnetic field-related phenomena we see occurs not only on stellar counterparts of our Sun but in stars that represent significant departures in their fundamental parameters from those of the Sun. Though these phenomena appear energetically negligible when compared to the total luminosity of stars, they nevertheless govern the angular momentum evolution and modulate the radiative and particle output of the Sun and late-type stars. The term "The Solar-Stellar Connection" has been coined to describe the solar-stellar synergisms in the investigation of the generation, emergence and coupling of magnetic fields with the outer solar-stellar atmosphere to produce what we broadly refer to as magnetic activity. With the discovery of literally thousands of planets beyond our solar system, the Solar-Stellar-Planet Connection is quickly emerging as a new area of investigation of the impacts of magnetic activity on exoplanet atmospheres. In parallel with this rapid evolution in our perspectives is the advent of transformative facilities for the study of the Sun and the dynamic Universe. The primary focus of this invited talk will be on photometric variations in solar-type stars and the Sun. These brightness variations are associated with thermal homogeneities typically defined by magnetic structures that are also spatially coincident with key radiative proxies. Photometric variability in solar-type stars and the Sun includes transient brightening, rotational modulation by cool spots and cycle-related variability, each with a characteristic signature in time and wavelength. The emphasis of this presentation will be on the relationship between broadband photometric variations and magnetic field-related activity in solar-type stars and the Sun. Facets of this topic will be discussed both retrospectively and prospectively as we enter a revolutionary, new era for astronomy.

  18. The Sun. A typical star in the solar neighborhood?

    CERN Document Server

    Melendez, Jorge

    2013-01-01

    The Sun is used as the fundamental standard in chemical abundance studies, thus it is important to know whether the solar abundance pattern is representative of the solar neighborhood. Albeit at low precision (0.05 - 0.10 dex) the Sun seems to be a typical solar-metallicity disk star, at high precision (0.01 dex) its abundance pattern seems abnormal when compared to solar twins. The Sun shows a deficiency of refractory elements that could be due to the formation of terrestrial planets. The formation of giant planets may also introduce a signature in the chemical composition of stars. We discuss both planet signatures and also the enhancement of neutron-capture elements in the solar twin 18 Sco.

  19. Solar Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Bob

    2011-04-27

    The Department of Energy, Golden Field Office, awarded a grant to the UNLV Research Foundation (UNLVRF) on August 1, 2005 to develop a solar and renewable energy information center. The Solar Technology Center (STC) is to be developed in two phases, with Phase I consisting of all activities necessary to determine feasibility of the project, including design and engineering, identification of land access issues and permitting necessary to determine project viability without permanently disturbing the project site, and completion of a National Environmental Policy Act (NEPA) Environmental Assessment. Phase II is the installation of infrastructure and related structures, which leads to commencement of operations of the STC. The STC is located in the Boulder City designated 3,000-acre Eldorado Valley Energy Zone, approximately 15 miles southwest of downtown Boulder City and fronting on Eldorado Valley Drive. The 33-acre vacant parcel has been leased to the Nevada Test Site Development Corporation (NTSDC) by Boulder City to accommodate a planned facility that will be synergistic with present and planned energy projects in the Zone. The parcel will be developed by the UNLVRF. The NTSDC is the economic development arm of the UNLVRF. UNLVRF will be the entity responsible for overseeing the lease and the development project to assure compliance with the lease stipulations established by Boulder City. The STC will be operated and maintained by University of Nevada, Las Vegas (UNLV) and its Center for Energy Research (UNLV-CER). Land parcels in the Eldorado Valley Energy Zone near the 33-acre lease are committed to the construction and operation of an electrical grid connected solar energy production facility. Other projects supporting renewable and solar technologies have been developed within the energy zone, with several more developments in the horizon.

  20. Design of solar cell lighting and sun tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Khaing, A.A. [Mandalay Technological Univ., Mandalay (Myanmar); Ministry of Science, Yangon (Myanmar)

    2008-07-01

    A solar cell lighting and sun tracking system was discussed and the characteristics of solar cells were studied. An SM50H solar module was analyzed with a maximum power rating of 50 W and a current rate of 3.15 A. The main components of the system include solar cells, charged controllers, and a sun tracking system. The solar tracker is an automatic control system designed to track the solar modules in relation to the sun's direction. A linear drive actuator was used to track the modules with an energy consumption rate between 24 and 36 DC voltages. Power output solar cell equations were presented along with a review of batteries used for stationary and portable solar energy equipment. Issues related to cost of tracking systems were discussed. System sizing recommendations were provided, and solar cell design requirements were reviewed. A comparison of tracking and fixed solar energy systems was presented for a day in Yangon, Myanmar. It was concluded that solar tracking systems can be used to provide energy in rural and remote areas. 18 refs., 4 tabs., 5 figs.

  1. A Community Python Library for Solar Physics (SunPy)

    Science.gov (United States)

    Christe, Steven; Shih, A. Y.; Ireland, J.; Perez-Suarez, D.; Mumford, S.; Hughitt, V. K.; Hewett, R.; Mayer, F.; SunPy Dev Team

    2013-07-01

    Python, a free, cross platform, general purpose, high-level programming language, has seen widespread adoption among the scientific community resulting in the availability of a large range of software, from numerical computation (NumPy, SciPy) and machine learning to spectral analysis and visualization (Matplotlib). SunPy is a data analysis toolkit specializing in providing the software necessary to analyze solar and heliospheric datasets in Python. It aims to provide a free and open-source alternative to the IDL-based SolarSoft (SSW) solar data analysis environment. We present the latest release of SunPy (0.3). This release includes a major refactor of the main SunPy code to improve ease of use for the user as well as a more consistent interface. SunPy provides downloading capability through integration with the Virtual Solar Observatory (VSO) and the the Heliophysics Event Knowledgebase (HEK). It can open image fits files from major solar missions (SDO/AIA, SOHO/EIT, SOHO/LASCO, STEREO) into WCS-aware maps. SunPy provides advanced time-series tools for data from mission such as GOES, SDO/EVE, and Proba2/LYRA as well as support for radio spectra (e.g. e-Callisto). We present examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing data analysis tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  2. The shrinking Sun: a systematic error in local correlation tracking of solar granulation

    CERN Document Server

    Löptien, B; Duvall, T L; Gizon, L; Schou, J

    2016-01-01

    Context. Local correlation tracking of granulation (LCT) is an important method for measuring horizontal flows in the photosphere. This method exhibits a systematic error that looks like a flow converging towards disk center, also known as the shrinking-Sun effect. Aims. We aim at studying the nature of the shrinking-Sun effect for continuum intensity data and at deriving a simple model that can explain its origin. Methods. We derived LCT flow maps by running the local correlation tracking code FLCT on tracked and remapped continuum intensity maps provided by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory. We also computed flow maps from synthetic continuum images generated from STAGGER code simulations of solar surface convection. We investigated the origin of the shrinking-Sun effect by generating an average granule from synthetic data from the simulations. Results. The LCT flow maps derived from HMI and from the simulations exhibit a shrinking-Sun effect of comparable mag...

  3. 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

    . 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...

  4. Circuits in the Sun: Solar Panel Physics

    Science.gov (United States)

    Gfroerer, Tim

    2013-01-01

    Typical commercial solar panels consist of approximately 60 individual photovoltaic cells connected in series. Since the usual Kirchhoff rules apply, the current is uniform throughout the circuit, while the electric potential of the individual devices is cumulative. Hence, a solar panel is a good analog of a simple resistive series circuit, except…

  5. Circuits in the Sun: Solar Panel Physics

    Science.gov (United States)

    Gfroerer, Tim

    2013-01-01

    Typical commercial solar panels consist of approximately 60 individual photovoltaic cells connected in series. Since the usual Kirchhoff rules apply, the current is uniform throughout the circuit, while the electric potential of the individual devices is cumulative. Hence, a solar panel is a good analog of a simple resistive series circuit, except…

  6. The solar chimney. Electricity from the sun

    Energy Technology Data Exchange (ETDEWEB)

    Schiel, W. [Schlaich, Bergermann und Partner, Stuttgart (Germany)

    1997-12-31

    Current energy production from coal and oil is damaging to the environment and non-renewable. Many developing countries cannot afford these energy sources, and nuclear power stations are an unacceptable risk in many locations. Inadequate energy supplies can lead to high energy costs as well as to proverty, which commonly results in population explosions. Sensible technology for the use of solar power must be simple and reliable, accessible to the technologically less developed countries that are sunny and often have limited raw materials resources, should not need cooling water or produce waste heat and should be based on environmentally sound production from renewable materials. The solar chimney meets these conditions and makes it possible to take the crucial step towards a global solar energy economy. Large scale solar chimneys can be built now without any technical problems and at defined costs. (orig.)

  7. Hybrid solar cells : Perovskites under the Sun

    NARCIS (Netherlands)

    Loi, Maria Antonietta; Hummelen, Jan C.

    2013-01-01

    Mixed-halide organic–inorganic hybrid perovskites are reported to display electron–hole diffusion lengths over 1 μm. This observation provides important insight into the charge-carrier dynamics of this class of semiconductors and increases the expectations for highly efficient and cheap solar cells.

  8. The LOFAR Solar Imaging Pipeline and the LOFAR Solar Data Center

    CERN Document Server

    Breitling, Frank; Vocks, Christian; Steinmetz, Matthias; Strassmeier, Klaus G

    2016-01-01

    LOFAR is a new and sensitive radio interferometer that can be used for dynamic high-resolution imaging spectroscopy at low radio frequencies from 10 to 90 and 110 to 250 MHz. Here we describe its usage for observations of the Sun and in particular of solar radio bursts. We also describe the processing, archiving and accessing of solar LOFAR data, which is accomplished via the LOFAR Solar Imaging Pipeline and the LOFAR Solar Data Center.

  9. Solar probe mission: close encounter with the sun

    Science.gov (United States)

    Sittler, E. C., Jr.; McComas, D. J.; McNutt, R. L., Jr.; Stdt Team

    The Solar Probe Science and Technology Definition Team (STDT) recently completed a detailed study of the Solar Probe Mission based on an earliest launch date of October 2014. Solar Probe, when implemented, will be the first close encounter by a spacecraft with a star (i.e., 3 RS above the Sun's photosphere). The report and its executive summary were published by NASA (NASA/TM-2005-212786) in September 2005 and can be found at the website http://solarprobe.gsfc.nasa.gov/. A description of the science will appear in Reviews of Geophysics article led by D. J. McComas. For this talk, we presented the consensus view of the STDT including a brief description of the scientific goals, a description of the overall mission, including trajectory scenarios, spacecraft description and proposed scientific payload. We will discuss all these topics and the importance of flying the Solar Probe mission both with regard to understanding fundamental issues of solar wind acceleration and coronal heating near the Sun and Solar Probe's unique role in understanding the acceleration of Solar Energetic Particles (SEPs), which is critical to future Human Exploration.

  10. SunPy 0.8 - Python for Solar Physics

    Science.gov (United States)

    Inglis, Andrew; Bobra, Monica; Christe, Steven; Hewett, Russell; Ireland, Jack; Mumford, Stuart; Martinez Oliveros, Juan Carlos; Perez-Suarez, David; Reardon, Kevin P.; Savage, Sabrina; Shih, Albert Y.; Ryan, Daniel; Sipocz, Brigitta; Freij, Nabil

    2017-08-01

    SunPy is a community-developed open-source software library for solar physics. It is written in Python, a free, cross-platform, general-purpose, high-level programming language which is being increasingly adopted throughout the scientific community. Python is one of the top ten most often used programming languages, as such it provides a wide array of software packages, such as numerical computation (NumPy, SciPy), machine learning (scikit-learn), signal processing (scikit-image, statsmodels) to visualization and plotting (matplotlib, mayavi). SunPy aims to provide the software for obtaining and analyzing solar and heliospheric data. This poster introduces a new major release of SunPy (0.8). This release includes two major new functionalities, as well as a number of bug fixes. It is based on 1120 contributions from 34 unique contributors. Fido is the new primary interface to download data. It provides a consistent and powerful search interface to all major data sources provides including VSO, JSOC, as well as individual data sources such as GOES XRS time series and and is fully pluggable to add new data sources, i.e. DKIST. In anticipation of Solar Orbiter and the Parker Solar Probe, SunPy now provides a powerful way of representing coordinates, allowing conversion between coordinate systems and viewpoints of different instruments, including preliminary reprojection capabilities. Other new features including new timeseries capabilities with better support for concatenation and metadata, updated documentation and example gallery. SunPy is distributed through pip and conda and all of its code is publicly available (sunpy.org).

  11. MWA Observations of Solar Radio Bursts and the Quiet Sun

    Science.gov (United States)

    Cairns, I.; Oberoi, D.; Morgan, J.; Bastian, T.; Bhatnagar, S.; Bisi, M.; Benkevitch, L.; Bowman, J.; Donea, A.; Giersch, O.; Jackson, B.; Chat, G. L.; Golub, L.; Hariharan, K.; Herne, D.; Kasper, J.; Kennewell, J.; Lonsdale, C.; Lobzin, V.; Matthews, L.; Mohan, A.; Padmanabhan, J.; Pankratius, V.; Pick, M.; Subramanian, P.; Ramesh, R.; Raymond, J.; Reeves, K.; Rogers, A.; Sharma, R.; Tingay, S.; Tremblay, S.; Tripathi, D.; Webb, D.; White, S.; Abidin, Z. B. Z.

    2017-01-01

    A hundred hours of observing time for solar observations is requested during the 2017-A observing semester. These data will be used to address science objectives for solar burst science (Goal A), studies of weak non-thermal radiation (Goal B) and quiet sun science (Goal C). Goal A will focus on detailed investigations of individual events seen in the MWA data, using the unsurpassed spectroscopic imaging ability of the MWA to address some key solar physics questions. Detailed observations of type II bursts, of which MWA has observed two, will be one focus, with MWA polarimetric imaging observations of type III bursts another focus. Goal B will address studies of the numerous short lived and narrow band emission features, significantly weaker than those seen by most other instruments revealed by the MWA. These emission features do not resemble any known types of solar bursts, but are possible signatures of "nanoflares" which have long been suspected to play a role in coronal heating. A large database of these events is needed to be able to reliably estimate their contribution to coronal heating. These observations will contribute to this database. Goal C will focus on characterizing the Sun's background thermal emission, their short and long term variability and looking for evidence of a scattering disc around the Sun.

  12. Evidence That Solar Flares Drive Global Oscillations in the Sun

    Science.gov (United States)

    Karoff, C.; Kjeldsen, H.

    2008-05-01

    Solar flares are large explosions on the Sun's surface caused by a sudden release of magnetic energy. They are known to cause local short-lived oscillations traveling away from the explosion like water rings. Here we show that the energy in the solar acoustic spectrum is correlated with flares. This means that the flares drive global oscillations in the Sun in the same way that the entire Earth is set ringing for several weeks after a major earthquake such as the 2004 December Sumatra-Andaman one. The correlation between flares and energy in the acoustic spectrum of disk-integrated sunlight is stronger for high-frequency waves than for ordinary p-modes which are excited by the turbulence in the near-surface convection zone immediately beneath the photosphere.

  13. User-centered development of a smart phone mobile application delivering personalized real-time advice on sun protection.

    Science.gov (United States)

    Buller, David B; Berwick, Marianne; Shane, James; Kane, Ilima; Lantz, Kathleen; Buller, Mary Klein

    2013-09-01

    Smart phones are changing health communication for Americans. User-centered production of a mobile application for sun protection is reported. Focus groups (n = 16 adults) provided input on the mobile application concept. Four rounds of usability testing were conducted with 22 adults to develop the interface. An iterative programming procedure moved from a specification document to the final mobile application, named Solar Cell. Adults desired a variety of sun protection advice, identified few barriers to use and were willing to input personal data. The Solar Cell prototype was improved from round 1 (seven of 12 tasks completed) to round 2 (11 of 12 task completed) of usability testing and was interoperable across handsets and networks. The fully produced version was revised during testing. Adults rated Solar Cell as highly user friendly (mean = 5.06). The user-centered process produced a mobile application that should help many adults manage sun safety.

  14. 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.

  15. 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.

    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.

  16. Solar sketching a comprehensive guide to drawing the sun

    CERN Document Server

    Rix, Erika; Russell, Sally; Handy, Richard

    2015-01-01

    From the authors of Sketching the Moon comes a comprehensive guide filled with richly illustrated, detailed drawing tutorials that cover a variety of solar phenomena. Time-honored, traditional methods and media are described in tandem with innovative techniques developed and shared by contemporary astronomical sketchers. Explanations of what to expect visually from white light, Hydrogen-alpha and Calcium K filters are provided for those new to solar observing, along with essential tips on equipment, observing techniques and the practicalities of drawing at the eyepiece. For the technically minded, detailed descriptions are given on how to use image manipulation software to bring your sketches to life through animation.   The Sun is the most visually dynamic object in our solar system and offers compelling, spectacular views. Knotted magnetic field lines give rise to powerful eruptions and form the intricate sunspots and arching prominences that make our nearest star one of the most exciting, yet challenging,...

  17. Solar Energy Education. Reader, Part I. Energy, Society, and the Sun

    Energy Technology Data Exchange (ETDEWEB)

    1981-05-01

    A collection of magazine articles which were selected for information on solar energy is presented in this booklet. This booklet is the first of a four part series of the Solar Energy Reader. The articles provide brief discussions on topics such as the power of the sun, solar energy developments for homes, solar energy versus power plants, solar access laws, and the role of utilities with respect to the sun's energy. (BCS)

  18. The Solar Dynamics Observatory: Your eye on the Sun

    Science.gov (United States)

    Pesnell, William

    The Solar Dynamics Observatory (SDO) was launched on February 11, 2010 into partly cloudy skies over Cape Canaveral, Florida. SDO has since moved into a 28 degree inclined geosyn-chronous orbit over the longitude of the ground station in New Mexico. SDO is the first Space Weather Mission in NASA's Living With a Star Program. SDO's main goal is to understand and predict those solar variations that influence life on Earth and our technological systems. The SDO science investigations will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. The SDO mission consists of three scientific investigations (AIA, EVE, and HMI), a spacecraft bus, and a ded-icated Ka-band ground station to handle the 150 Mbps data flow. Science teams at LMSAL, LASP, and Stanford are responsible for processing, analyzing, distributing, and archiving the science data. We will talk about the building of SDO, its launch, and the data and science it will provide to NASA.

  19. FTS atlas of the Sun's spectrally resolved center-to-limb variation

    CERN Document Server

    Stenflo, Jan

    2014-01-01

    The Sun's spectrum varies with center-to-limb distance. This variation is governed by the underlying temperature-density structure of the solar atmosphere. To explore the spectrally resolved center-to-limb variation (CLV) we make use of two spectral atlases recorded with the Fourier transform spectrometer (FTS) at the McMath-Pierce facility at Kitt Peak. One spectral atlas obtained 10 arcsec inside the solar limb was recorded in 1978-79 as part of the first survey of the Second Solar Spectrum, while the other atlas is the well used reference NSO/Kitt Peak FTS atlas for the disk center. Both atlases represent fully resolved spectra without any spectral stray light. We then construct an atlas of the limb/disk-center ratio between the two spectra over the wavelength range 4084-9950 \\AA. This ratio spectrum, which expresses the CLV amplitude relative to the continuum, is as richly structured as the intensity spectrum itself, but the line profiles differ greatly in both shape and amplitude. It is as if we are deal...

  20. Evolution of lithium abundance in the Sun and solar twins

    Science.gov (United States)

    Thévenin, F.; Oreshina, A. V.; Baturin, V. A.; Gorshkov, A. B.; Morel, P.; Provost, J.

    2017-02-01

    Evolution of the 7Li abundance in the convection zone of the Sun during different stages of its life time is considered to explain its low photospheric value in comparison with that of the solar system meteorites. Lithium is intensively and transiently burned in the early stages of evolution (pre-main sequence, pMS) when the radiative core arises, and then the Li abundance only slowly decreases during the main sequence (MS). We study the rates of lithium burning during these two stages. In a model of the Sun, computed ignoring pMS and without extra-convective mixing (overshooting) at the base of the convection zone, the lithium abundance does not decrease significantly during the MS life time of 4.6 Gyr. Analysis of helioseismic inversions together with post-model computations of chemical composition indicates the presence of the overshooting region and restricts its thickness. It is estimated to be approximately half of the local pressure scale height (0.5HP) which corresponds to 3.8% of the solar radius. Introducing this extra region does not noticeably deplete lithium during the MS stage. In contrast, at the pMS stage, an overshooting region with a value of approximately 0.18HP is enough to produce the observed lithium depletion. If we conclude that the dominant lithium burning takes place during the pMS stage, the dispersion of the lithium abundance in solar twins is explained by different physical conditions, primarily during the early stage of evolution before the MS.

  1. Tracing the journey of the sun and the solar siblings through the Milky Way

    NARCIS (Netherlands)

    Martinez, Barbosa C.A.

    2016-01-01

    This thesis is focused on studying the motion of the Sun and the Solar siblings through the Galaxy. The Solar siblings are stars that were born with the Sun in the same molecular cloud 4.6 Gyr ago. In the first part of the thesis, we present an efficient method to calculate the evolution of small

  2. Solar Mosaic Inc. Mosaic Home Solar Loan SunShot 9 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Colin James [Solar Mosaic Inc., Oakland, CA (United States)

    2017-02-09

    The 6686 Mosaic SunShot award has helped Solar Mosaic Inc to progress from an early stage startup focused on commercial crowdfunding to a leading multi-state residential solar lender. The software platform is now used by the majority of the nation's top solar installers and offers a variety of simple home solar loans. Mosaic is has originated approximately $1Bil in solar loans to date to put solar on over 35k rooftops. The company now lends to homeowners with a wide range of credit scores across multiple states and mitigates boundaries preventing them from profiting from ownership of a home solar system. The project included milestones in 5 main categories: 1. Lending to homeowners outside of CA 2. Lending to homeowners with FICO scores under 700 3. Packaging O&M with the home solar loan 4. Allowing residential installers to process home solar loans via API 5. Lowering customer acquisition costs below $1500 This report includes a detailed review of the final results achieved and key findings.

  3. Sun

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Sun Microsystems, Inc. is committed to open standards,a standardization system, and sharing within the information tech nology field, focusing not only on technical innovation, but also on new ideas, practices and future development.

  4. Vertical InGaN-based green-band solar cells operating under high solar concentration up to 300 suns.

    Science.gov (United States)

    Sheu, Jinn-Kong; Chen, Fu-Bang; Wu, Shou-Hung; Lee, Ming-Lun; Chen, Po-Cheng; Yeh, Yu-Hsiang

    2014-08-25

    InGaN/GaN-based solar cells with vertical-conduction feature on silicon substrates were fabricated by wafer bonding technique. The vertical solar cells with a metal reflector sandwiched between the GaN-based epitaxial layers and the Si substrate could increase the effective thickness of the absorption layer. Given that the thermally resistive sapphire substrates were replaced by the Si substrate with high thermal conductivity, the solar cells did not show degradation in power conversion efficiency (PCE) even when the solar concentrations were increased to 300 suns. The open circuit voltage increased from 1.90 V to 2.15 V and the fill factor increased from 0.55 to 0.58 when the concentrations were increased from 1 sun to 300 suns. With the 300-sun illumination, the PCE was enhanced by approximately 33% compared with the 1-sun illumination.

  5. Detection of Small-Scale Granular Structures in the Quiet Sun with the New Solar Telescope

    CERN Document Server

    Abramenko, Valentyna; Goode, Philip; Kitiashvili, Irina; Kosovichev, Alexander

    2012-01-01

    Results of a statistical analysis of solar granulation are presented. A data set of 36 images of a quiet Sun area on the solar disk center was used. The data were obtained with the 1.6 m clear aperture New Solar Telescope (NST) at Big Bear Solar Observatory (BBSO) and with a broad-band filter centered at the TiO (705.7 nm) spectral line. The very high spatial resolution of the data (diffraction limit of 77 km and pixel scale of 0.$"$0375) augmented by the very high image contrast (15.5$\\pm$0.6%) allowed us to detect for the first time a distinct subpopulation of mini-granular structures. These structures are dominant on spatial scales below 600 km. Their size is distributed as a power law with an index of -1.8 (which is close to the Kolmogorov's -5/3 law) and no predominant scale. The regular granules display a Gaussian (normal) size distribution with a mean diameter of 1050 km. Mini-granular structures contribute significantly to the total granular area. They are predominantly confined to the wide dark lanes...

  6. SunPy - Python for Solar Physics, Version 0.4

    Science.gov (United States)

    Christe, Steven; Mumford, Stuart; Perez-Suarez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon; Hewett, Russel

    2014-06-01

    We presents version 0.4 of SunPy, a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation NumPy, SciPy and machine learning (scikit-learn) to visualisation and plotting (matplotlib).SunPy is a data-analysis environment specialising in providing the software necessary to analyse solar and heliospheric datasets in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from missions such as GOES, SDO/EVE, and PROBA2/LYRA, and radio spectra from e-Callisto and STEREO/SWAVES. We describe SunPy's functionality, provide examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  7. Analysis of the Sun Tracking Systems to Optimize the Efficiency of Solar Panels

    Directory of Open Access Journals (Sweden)

    Ngo Xuan Cuong

    2016-12-01

    Full Text Available One of the ways to improve the efficiency of solar cells and reduce the price of solar electricity is the use of the tracking system of the sun. Daily and seasonal movement of the Earth affects the intensity of the radiation on the solar panels. The tracking system is the sun moves the solar panels to compensate for these movements, keeping the best orientation to the sun. For small solar panels it is not recommended to use the tracking system because of the high energy losses in the drive. It was found that the power consumption of the servo system is a few % of the increased energy. This article provides a classification system for tracking the sun, considered and their pluses and minuses.

  8. 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.

  9. 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.

  10. Systems and methods for concentrating solar energy without tracking the sun

    OpenAIRE

    Kornfield, Julia A.; Flagan, Richard C.

    2014-01-01

    Systems and methods for concentrating solar energy without tracking the sun are provided. In one embodiment, the invention relates to a solar collector assembly for collecting and concentrating light for solar cell assemblies, the collector assembly including an array of solar collectors, each including a funnel shaped collector including a side wall defining a tapered opening having a base aperture and an upper aperture, the side wall including an outer surface, and a solar cell assembly pos...

  11. Midnight sun

    Energy Technology Data Exchange (ETDEWEB)

    Brunger, A.P.; Lambert, S.B.; Gagnon, M.P.

    1990-09-01

    Midnight Sun, the University of Waterloo's solar-electric car, was designed and built by about 30 engineering, kinesiology and physics students for the GM Sunrayce USA held in July 1990. The car measures 2 m by 4.2 m, weighs 224 kg, can collect about 1000 W of solar electricity in full sun, and had a top speed of 79 km/h. The race took 11 days to cover the 1644 miles from the Epcot Center in Lake Buena Vista, Florida to the GM Technical Center in Warren, Michigan. Thirty-two cars, powered only by solar energy, competed in this race. Midnight Sun showed its potential during the race qualifying runs by completing the required qualifying course with the 12th fastest time of 52.83 seconds, and the 6th fastest trap speed of 63 km/h. During the Sunrayce, Midnight Sun came in second on day 1 of the race, tenth on day 6, and eighth on day 7, and was one of only 17 solar cars that were able to make it up the toughest hill in the race on day 8. The most serious problems encountered by the car were a weak rear suspension, power losses, and failure of bypass diodes in the photovoltaic array. Midnight Sun was in 17th place overall at the end of day 9. At about 11:00 am on day 10 in Ohio, the Waterloo car was moving at 60 km/h when it was bumped off the road by an out of control pickup truck. The solar car driver was not hurt. Despite the difficulties, the next day Midnight Sun was repaired and driven across the finish line at the ceremonial finish. After receiving time penalties for not completing the last day and a half of the race, Midnight Sun was awarded 24th place with an official cumulative time of 114 h 37 min 15 s. 4 figs., 4 tabs.

  12. Hot water from the sun: a consumer guide to solar water heating

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, Beth

    2005-02-15

    The following topics are discussed: how solar water heaters work, making good use of the sun, estimating costs and savings, choosing the right dealer/installer, choosing the right system, warranties and contracts, getting a good installation, and living with your solar energy system. The appendices discuss system performance and durability, and provide sources of additional information on solar energy and its applications. (MHR)

  13. Spectral atlases of the Sun from 3980 to 7100 {\\AA} at the center and at the limb

    CERN Document Server

    Fathivavsari, Hassan; Koutchmy, Serge

    2014-01-01

    In this work, we present digital and graphical atlases of spectra of both the solar disk-center and of the limb near the Solar poles using data taken at the UTS-IAP & RIAAM (the University of Tabriz Siderostat, telescope and spectrograph jointly developed with the Institut d'Astrophysique de Paris and Research Institute for Astronomy and Astrophysics of Maragha). High resolution and high signal-to-noise ratio (SNR)CCD-slit spectra of the sun for 2 different parts of the disk, namely for $\\mu$~=~1.0 (solar center) \\& for $\\mu$~=~ 0.3 solar limb) are provided and discussed. While there are several spectral atlases of the solar disk-center, this is the first spectral atlas ever produced for the solar limb at this spectral range. The resolution of the spectra is about \\emph{R}~$\\sim$~70 000 ($\\Delta\\lambda$~$\\sim$~0.09 {\\AA} with the signal-to-noise ratio (SNR) of 400$-$600. The full atlas covers the 3980 to 7100 {\\AA} spectral regions and contains 44 pages with three partial spectra of the solar spectrum...

  14. Situation of China's solar water heater industry, related national standards, testing and the Golden Sun certification program

    Institute of Scientific and Technical Information of China (English)

    YAN Jun; H.Druck; H.Muller-Steinhagen

    2008-01-01

    China is the largest solar water heater producer and market in the world. Despite the fast growth and an installed capacity that accounts for the majority of the global gross, China's per capita solar hot water capacity is still very low, implying a huge margin of market potential; and the recognition of the industry in the global market is handicapped by the scattered scale of production and inconsistent product quality. To ensure continued growth of China's solar water heating (SWH) industry, Chinese Government has established a series of national SWH standards, three national testing centers, and a certification program to lay the foundation for the development of the Golden Sun product labeling system. China General Certification Center (CGC) developed the Golden Sun product certification and labeling system on a pass/fail basis evaluating with established criteria. The system was designed to help manufacturers acclimate to explicit consistent requirements and to identify and fix the deficiencies in the design and execution of the program itself. Timely revision and integration of the national standards are recommended to accommodate the test procedures and requirements to new technologies and the evolving SWH market. Strict implementation of the Golden Sun certification and labeling system are suggested to avail improving the quality control and forging internationally reputable brands of Chinese solar water heating products.

  15. Probing Solar Magnetic Field with the "Cosmic-Ray Shadow" of the Sun

    CERN Document Server

    Amenomori, M; Chen, D; Chen, T L; Chen, W Y; Cui, S W; Danzengluobu,; Ding, L K; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gou, Q B; Guo, Y Q; Hakamada, K; He, H H; He, Z T; Hibino, K; Hotta, N; Hu, Haibing; Hu, H B; Huang, J; Jia, H Y; Jiang, L; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren,; Le, G M; Li, A F; Li, H J; Li, W J; Liu, C; Liu, J S; Liu, M Y; Lu, H; Meng, X R; Mizutani, K; Munakata, K; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ozawa, S; Qian, X L; Qu, X B; Saito, T; Saito, T Y; Sakata, M; Sako, T K; Shao, J; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, H; Wu, H R; Xue, L; Yamamoto, Y; Yang, Z; Yasue, S; Yuan, A F; Yuda, T; Zhai, L M; Zhang, H M; Zhang, J L; Zhang, X Y; Zhang, Y; Zhang, Yi; Zhang, Ying; Zhaxisangzhu,; Zhou, X X

    2013-01-01

    We report on a clear solar-cycle variation of the Sun's shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun's shadow, using the Potential Field Source Surface (PFSS) model and the Current Sheet Source Surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun's shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun's shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun's shadow observed in the TeV cosmic-ray flux.

  16. A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations

    Science.gov (United States)

    Brooks, David H.; Baker, Deborah; van Driel-Gesztelyi, Lidia; Warren, Harry P.

    2017-08-01

    The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar Dynamics Observatory, to show that when the Sun is observed as a star, the variation of coronal composition is highly correlated with a proxy for solar activity, the F10.7 cm radio flux, and therefore with the solar cycle phase. Similar cyclic variations should therefore be detectable spectroscopically in X-ray observations of solar analogs. The plasma composition in full-disk observations of the Sun is related to the evolution of coronal magnetic field activity. Our observations therefore introduce an uncertainty into the nature of any relationship between coronal composition and fixed stellar properties. The results highlight the importance of systematic full-cycle observations for understanding the elemental composition of solar-like stellar coronae.

  17. Seguidor Solar de Dos Ejes para un Horno Solar Two-Axis Sun Tracking System for a Solar Furnace

    Directory of Open Access Journals (Sweden)

    Gabriel Villeda

    2011-01-01

    Full Text Available Se presenta el diseño y fabricación de un seguidor solar de dos ejes (rotación-elevación, el cual controla un helióstato de un horno solar para la cocción de tabiques de arcilla. El sistema trabaja con motores controlados desde una computadora personal. El algoritmo para el seguidor solar se desarrolló en un lenguaje de programación visual, calcula los ángulos de seguimiento primario y secundario del helióstato y los despliega en una pantalla. El microcontrolador está programado para controlar el funcionamiento de los motores a pasos, los cuales mueven el helióstato del horno solar. El seguimiento primario y secundario es el mismo para los equinoccios, mientras que para los solsticios son diferentes debido a que durante el verano en el hemisferio norte existe mayor altura solar que en invierno. El seguidor solar permite una captación más eficiente de la radiación solar debido a que sigue minuto a minuto el movimiento aparente del Sol.The design and manufacture of a two-axis sun tracking system (rotation-elevation, which controls a heliostat of a solar furnace for clay brick firing is presented. The system works with motors controlled through a personal computen The algorithm for the sun tracking system was developed in a visual programming language, calculates the primary and secondary tracking angles of the heliostat and shows them in a screen. The microcontroller is programmed to control the step driver engines, which move the heliostat of the solar furnace. The primary and secondary tracking is the same for the equinoxes, whereas for the solstices are different because the solar altitude is greater in summer than in winter in the northern hemisphere. The sun tracking system permits a more efficient capture of the solar radiation since it continuously follows the apparent movement of the Sun.

  18. Pigment developed to protect spacecraft/solar cells from Sun's harmful rays.

    Science.gov (United States)

    1995-01-01

    A pigment (phthalocyanine) is studied at the Marshall Materials and Processes Lab. The pigment has the ability to protect spacecraft against the harmful effects of the Sun's ultraviolet rays, and to increase the efficiency and life of solar cells.

  19. On the Path to SunShot: Emerging Opportunities and Challenges in Financing Solar

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bolinger, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-05-01

    This report analyzes solar financing strategies and their role in achieving the U.S. Department of Energy's SunShot goals. Financing is critical to solar deployment, because the costs of solar technologies are paid up front, while their benefits are realized over decades. Solar financing has been shaped by government solar incentives, particularly federal tax incentives, which have spawned complex tax-equity structures that monetize tax benefits for project sponsors who otherwise could not use them efficiently. Although these structures have helped expand solar deployment, they are relatively costly and inefficient. This has spurred solar stakeholders to develop lower-cost financing solutions such as securitization of solar project portfolios, solar-specific loan products, and methods for incorporating residential solar's value into home values. To move solar further toward an unsubsidized SunShot future, additional financial innovation must occur. Development of a larger, more mature U.S. solar industry will likely increase financial transparency and investor confidence, which in turn will enable simpler, lower-cost financing methods. Utility-scale solar might be financed more like conventional generation assets are today, non-residential solar might be financed more like a new roof, and residential solar might be financed more like an expensive appliance. Assuming a constant, SunShot-level installed photovoltaic (PV) system price, such financing innovations could reduce PV's levelized cost of electricity (LCOE) by an estimated 25%-50% compared with historical financing approaches. These results suggest that financing can adapt to changing conditions and might ease the transition away from a reliance on tax incentives while driving solar's LCOE toward the SunShot goals.

  20. The Sun to the Earth - and Beyond: A Decadal Research Strategy in Solar and Space Physics

    Science.gov (United States)

    2003-01-01

    The sun is the source of energy for life on earth and is the strongest modulator of the human physical environment. In fact, the Sun's influence extends throughout the solar system, both through photons, which provide heat, light, and ionization, and through the continuous outflow of a magnetized, supersonic ionized gas known as the solar wind. While the accomplishments of the past decade have answered important questions about the physics of the Sun, the interplanetary medium, and the space environments of Earth and other solar system bodies, they have also highlighted other questions, some of which are long-standing and fundamental. The Sun to the Earth--and Beyond organizes these questions in terms of five challenges that are expected to be the focus of scientific investigations in solar and space physics during the coming decade and beyond. While the accomplishments of the past decades have answered important questions about the physics of the Sun, the interplanetary medium, and the space environments of Earth and other solar system bodies, they have also highlighted other questions, some of which are long-standing and fundamental. This report organizes these questions in terms of five challenges that are expected to be the focus of scientific investigations in solar and space physics during the coming decade and beyond: Challenge 1: Understanding the structure and dynamics of the Sun's interior, the generation of solar magnetic fields, the origin of the solar cycle, the causes of solar activity, and the structure and dynamics of the corona. Challenge 2: Understanding heliospheric structure, the distribution of magnetic fields and matter throughout the solar system, and the interaction of the solar atmosphere with the local interstellar medium. Challenge 3: Understanding the space environments of Earth and other solar system bodies and their dynamical response to external and internal influences. Challenge 4: Understanding the basic physical principles manifest

  1. JPSS-1 VIIRS solar diffuser stability monitor response versus sun angle of incidence

    Science.gov (United States)

    Murgai, Vijay; Yu, Kristie; Nelson, Neil; McCarthy, James

    2015-09-01

    The Visible/Infrared Imaging Radiometer Suite (VIIRS) is a key sensor on the Suomi National Polar-orbiting Partnership (NPP) satellite in orbit as well as for the upcoming Joint Polar Satellite System (JPSS). VIIRS collects Earth radiometry and imagery in 22 spectral from 0.4 to 12.5 μm. Radiometric calibration of the reflective bands in the 0.4 to 2.5 μm wavelength range is performed by measuring the sunlight reflectance from Solar Diffuser Assembly (diffuser is Spectralon®). Spectralon® is known to solarize due to sun UV exposure at the blue end of the spectrum (~0.4 - 0.6+ μm) as seen by laboratory tests as well as on orbit data from MODIS and NPP. VIIRS uses a Solar Diffuser Stability Monitor (SDSM) to monitor the change in the Solar Diffuser reflectance in the 0.4 - 0.94 μm wavelength range to correct the calibration constants. The SDSM measures the ratio of sun light reflecting from the Solar Diffuser to a direct view of the sun. As the intensity of the light reaching the SDSM in both Solar Diffuser view and sun view is a function of the sun's angle of incidence (AOI), the SDSM response to sun AOI has to be characterized. This paper presents details of the test setup including an extended collimated source simulating the sun across all SDSM bands. The prelaunch characterization results for the JPSS-1 (J1) VIIRS SDSM are presented. Comparison with NPP on orbit yaw maneuver SDSM results shows similar behavior demonstrating that the J1 test successfully characterized the SDSM response to sun AOI.

  2. Modeling the Young Sun's Solar Wind and its Interaction with Earth's Paleomagnetosphere

    CERN Document Server

    Sterenborg, M Glenn; Drake, Jeremy J; Gombosi, Tamas I; 10.1029/2010JA016036

    2011-01-01

    We present a focused parameter study of solar wind - magnetosphere interaction for the young Sun and Earth, $~3.5$ Ga ago, that relies on magnetohydrodynamic (MHD) simulations for both the solar wind and the magnetosphere. By simulating the quiescent young Sun and its wind we are able to propagate the MHD simulations up to Earth's magnetosphere and obtain a physically realistic solar forcing of it. We assess how sensitive the young solar wind is to changes in the coronal base density, sunspot placement and magnetic field strength, dipole magnetic field strength and the Sun's rotation period. From this analysis we obtain a range of plausible solar wind conditions the paleomagnetosphere may have been subject to. Scaling relationships from the literature suggest that a young Sun would have had a mass flux different from the present Sun. We evaluate how the mass flux changes with the aforementioned factors and determine the importance of this and several other key solar and magnetospheric variables with respect t...

  3. Minimal Magnetic States of the Sun and the Solar Wind: Implications for the Origin of the Slow Solar Wind

    Science.gov (United States)

    Cliver, E. W.; von Steiger, R.

    2017-09-01

    During the last decade it has been proposed that both the Sun and the solar wind have minimum magnetic states, lowest order levels of magnetism that underlie the 11-yr cycle as well as longer-term variability. Here we review the literature on basal magnetic states at the Sun and in the heliosphere and draw a connection between the two based on the recent deep 2008-2009 minimum between cycles 23 and 24. In particular, we consider the implications of the low solar activity during the recent minimum for the origin of the slow solar wind.

  4. Solar-Terrestrial Relations: An Undergraduate-Level Introduction to the Sun, Space Weather, and the Sun-Climate Connection

    Science.gov (United States)

    Liemohn, M. W.; Zurbuchen, T.

    2011-12-01

    The University of Michigan offers a 300-level course entitled, "Solar-Terrestrial Relations," taken by all of the undergraduate students in the Atmospheric, Oceanic, and Space Sciences department. This is the first class in the space physics courses leading to a concentration in Space Weather. The course provides an overview of the Sun and solar radiation, both photon and particle, and its variability on all time scales. The effects of this variability on the near-Earth space environment and the Earth's climate are then discussed. The class content is a mixture of conceptual, theoretical, and analytical techniques. The students spend one session a week in a computer lab visiting data websites, downloading and processing the numbers, and interpreting the results. In addition to homework sets and exams, the students also do two projects, both including written and oral reports. The first is a space weather event analysis in which each student is assigned a storm day and they must determine the solar source and whether there was aurora over Ann Arbor during the event. The second project is a group effort on some aspect of the Sun-climate relationship, in which they are given a hypothesis and must conduct a literature search and data analysis exercise to support or refute it.

  5. Commentary on the Liquid Metallic Hydrogen Model of the Sun III. Insight into Solar Lithium Abundances

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-04-01

    Full Text Available The apparent depletion of lithium represents one of the grea test challenges to modern gaseous solar models. As a result, lithium has been hypothes ized to undergo nuclear burning deep within the Sun. Conversely, extremely low lith ium abundances can be easily accounted for within the liquid metallic hydrogen mo del, as lithium has been hypothesized to greatly stabilize the formation of metalli c hydrogen (E. Zurek et al. A little bit of lithium does a lot for hydrogen. Proc. Nat. Acad. Sci. USA , 2009, v. 106, no. 42, 17640–17643. Hence, the abundances of lithium on th e solar surface can be explained, not by requiring the nuclear burning of this elem ent, but rather, by suggesting that the Sun is retaining lithium within the solar body in ord er to help stabilize its liquid metallic hydrogen lattice. Unlike lithium, many of t he other elements synthesized within the Sun should experience powerful lattice exclusio nary forces as they are driven out of the intercalate regions between the layered liquid me tallic hydrogen hexagonal planes (Robitaille J.C. and Robitaille P.M. Liquid Metalli c Hydrogen III. Intercalation and Lattice Exclusion Versus Gravitational Settling and Th eir Consequences Relative to Internal Structure, Surface Activity, and Solar Winds in the Sun. Progr. Phys ., 2013, v. 2, in press. As for lithium, its stabilizing role within t he solar interior helps to account for the lack of this element on the surface of the Sun.

  6. The possibility of forming an inhomogeneous Sun and the solar neutrino effect

    Science.gov (United States)

    Levy, E. H.; Ruzmaikina, T. V.

    1994-01-01

    Recent observations confirm that the flux of neutrinos from the interior of the Sun is significantly less than what is expected on the basis of solar models. It has long been known that a low neutrino flux could result from a temperature in the Sun's core lower than the approximately 1.5 x 10(exp 7) K central temperature given by standard solar models. A low central temperature could occur if the solar interior were depleted in the so-called metals -- atomic species heavier than helium -- resulting in lower internal opacity. In this case, chemical abundances measured in the solar convection zone would be unrepresentative of the deep-interior abundances. The possibility of a compositionally inhomogeneous Sun has usually been discarded on the basis of cosmogonical arguments against the formation of such nonhomogeneity. This paper suggests that compositional nonhomogeneity could have arisen through unremarkable physical processes during the formation of the Sun, and that a compositionally inhomogeneous Sun remains a viable possibility for investigation of the solar neutrino problem.

  7. Sun-genesis 21: Empowering the global village in the digital age and the solar century

    Energy Technology Data Exchange (ETDEWEB)

    Hamasaki, Les [Los Angeles, CA (United States)

    2000-07-01

    Sun-Genesis 21 is a global economic development plan for creating an environmentally sustainable future in the developing world. Its premise is that the solution to the survival of civil stability and democracy in developing countries in the Information Age is to slow the migration of the rural poor into the urban centers as well as dispersing some of the residents of the already impacted cities into new agro-communities. This strategy envisions empowering the 25 million coffee farmers located in the poorest countries in the world to control their own economic destiny by marketing their products directly to the international marketplace over the World Wide Web (Coffee Belt Plan 2020). The plan also envisions creating a network of new agricultural communities called World Farm Solar Telecommunities that utilizes telecommunications and environmental technologies to disperse the impacted urban population. Proven profitable commodities such as industrial hemp, aloe vera, and aquacultural farming will be the economic foundation of these agro-communities. The goal is to empower rural agro-entrepreneurs to become an economic engine for job creation and be able to afford the Coffee Solar Televillages that include distant learning centers, telemedicine clinics, food processing centers, e-commerce centers, and solar crop-drying centers. The Genesis 21 program includes creative financing strategies to deal with these massive problems of poverty and hunger through the concept of trade, not aid, including the use of barter in a proposed Green Technology for Green Coffee program. [Spanish] Sun-Genesis 21 es un plan global de desarrollo economico para crear un futuro ambiental sustentable en el mundo en desarrollo. La premisa del plan es que la solucion para la supervivencia de la estabilidad civil y la democracia en paises en desarrollo dentro de la Era de la Informacion es desacelerar la migracion de la gente pobre de las areas rurales hacia los centros urbanos, asi como

  8. A Solar Cell That Is Triggered by Sun and Rain.

    Science.gov (United States)

    Tang, Qunwei; Wang, Xiaopeng; Yang, Peizhi; He, Benlin

    2016-04-18

    All-weather solar cells are promising in solving the energy crisis. A flexible solar cell is presented that is triggered by combining an electron-enriched graphene electrode with a dye-sensitized solar cell. The new solar cell can be excited by incident light on sunny days and raindrops on rainy days, yielding an optimal solar-to-electric conversion efficiency of 6.53 % under AM 1.5 irradiation and current over microamps as well as a voltage of hundreds of microvolts by simulated raindrops. The formation of π-electron|cation electrical double-layer pseudocapacitors at graphene/raindrop interface is contributable to current and voltage outputs at switchable charging-discharging process. The new concept can guide the design of advanced all-weather solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. 2007 Solar Decathlon: Powered by the Sun (Competition Program)

    Energy Technology Data Exchange (ETDEWEB)

    2007-09-01

    The 2007 Solar Decathlon Competition Program is distributed to Solar Decathlon visitors, media, sponsors, and the student competitors. It contains basic facts about the Solar Decathlon: what, where, when, who, and how. It is a guide for visitors to the events and workshops. It describes the 10 contests and the technologies used in the houses. It celebrates the accomplishments of the competitors and provides an opportunity for the major sponsors to describe their roles and relay their commitment to the ideals of the Solar Decathlon.

  10. The chemical composition of the Sun from helioseismic and solar neutrino data

    CERN Document Server

    Villante, F L; Delahaye, F; Pinsonneault, M H

    2013-01-01

    We perform a quantitative analysis of the solar composition problem by using a statistical approach that allows us to combine the information provided by helioseimic and solar neutrino data in an effective way. We include in our analysis the helioseismic determinations of the surface helium abundance and of the depth of the convective envelope, the measurements of the $^7{\\rm Be}$ and $^8{\\rm B}$ neutrino fluxes, the sound speed profile inferred from helioseismic frequencies. We provide all the ingredients to describe how these quantities depend on the solar surface composition and to evaluate the (correlated) uncertainties in solar model predictions. We include errors sources that are not traditionally considered such as those from inversion of helioseismic data. We, then, apply the proposed approach to infer the chemical composition of the Sun. We show that the opacity profile of the Sun is well constrained by the solar observational properties. In the context of a two parameter analysis in which elements a...

  11. Full-Sun observations for identifying the source of the slow solar wind.

    Science.gov (United States)

    Brooks, David H; Ugarte-Urra, Ignacio; Warren, Harry P

    2015-01-06

    Fast (>700 km s(-1)) and slow (~400 km s(-1)) winds stream from the Sun, permeate the heliosphere and influence the near-Earth environment. While the fast wind is known to emanate primarily from polar coronal holes, the source of the slow wind remains unknown. Here we identify possible sites of origin using a slow solar wind source map of the entire Sun, which we construct from specially designed, full-disk observations from the Hinode satellite, and a magnetic field model. Our map provides a full-Sun observation that combines three key ingredients for identifying the sources: velocity, plasma composition and magnetic topology and shows them as solar wind composition plasma outflowing on open magnetic field lines. The area coverage of the identified sources is large enough that the sum of their mass contributions can explain a significant fraction of the mass loss rate of the solar wind.

  12. Full-Sun observations for identifying the source of the slow solar wind

    CERN Document Server

    Brooks, David H; Warren, Harry P

    2016-01-01

    Fast (>700 km/s) and slow (~400 km/s) winds stream from the Sun, permeate the heliosphere and influence the near-Earth environment. While the fast wind is known to emanate primarily from polar coronal holes, the source of the slow wind remains unknown. Here we identify possible sites of origin using a slow solar wind source map of the entire Sun, which we construct from specially designed, full- disk observations from the Hinode satellite, and a magnetic field model. Our map provides a full-Sun observation that combines three key ingredients for identifying the sources: velocity, plasma composition and magnetic topology and shows them as solar wind composition plasma outflowing on open magnetic field lines. The area coverage of the identified sources is large enough that the sum of their mass contributions can explain a significant fraction of the mass loss rate of the solar wind.

  13. Follow the sun - solar tracking; Immer der Sonne nach

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Fred

    2013-10-01

    The new personal use solar system MSS of Deger Energie (Horb am Neckar, Germany) allows a wide autonomy in the power supply. For commercial customers too. [German] Das neue Solarsystem MSS (Maximum Solar Speicher) von Deger Energie in Horb am Neckar erlaubt weitgehende Autonomie in der Stromversorgung. Auch fuer Gewerbekunden.

  14. Solar hydrogen: harvesting light and heat from sun (Presentation Recording)

    Science.gov (United States)

    Guo, Liejin; Jing, Dengwei

    2015-09-01

    My research group in the State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF), Xi'an Jiaotong University has been focusing on renewable energy, especially solar hydrogen, for about 20 years. In this presentation, I will present the most recent progress in our group on solar hydrogen production using light and heat. Firstly, "cheap" photoelectrochemical and photocatalytic water splitting, including both nanostructured materials and pilot-scale demonstration in our group for light-driven solar hydrogen (artificial photosynthesis) will be introduced. Then I will make a deep introduction to the achievements on the thermal-driven solar hydrogen, i.e., biomass/coal gasification in supercritical water for large-scale and low-cost hydrogen production using concentrated solar light.

  15. Access to solar energy: who owns the sun

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, J.N.

    If solar advocates should litigate for the free attainment of solar access to encourage solar energy, this would impinge directly on other people's property rights. Passage of such legislation would contradict the United States' historical acceptance of the cujus est solum...doctrine. This proprietary franchise recognizes the individual's right to use privately-owned airspace which has been legally acknowledged as separable and conveyable. A legislative attempt to redefine the property rights in the airspace over another's real estate would be a significant break with the United States legal tradition. Such action could constitute an economically inefficient and inequitable taking of property rights and reductions in property values for certain real estate owners. In Virginia, the Virginia Solar Easements Act, the text of which is appended, provides an explicit mechanism to obtain and register solar easements in those cases where the solar user fears a potential shade problem from a neighbor's real estate and where the solar user employs a market based mechanism to insure his receipt of sunlight from across another's property.

  16. The solar neutrino problem: Mixing of neutrinos and mixing in the sun

    Science.gov (United States)

    Haxton, W. C.

    I review the current status of the solar neutrino problem, including the exciting possibility of matter enhanced neutrino oscillations. Neutrino flux measurements, independent of questions of solar dynamics, appear to leave only one competing candidate astrophysical solution, at least in the case of steady-state solar models. That possibility - mixing of the solar core on time scales of 3He equilibration - appears to have some attractive features. A “score card” is presented in which the two alternatives - mixed neutrinos or a mixed sun - are handicapped.

  17. Ulysses returns to the Sun's south pole and encounters blustery solar weather

    Science.gov (United States)

    2000-09-01

    Conditions are very different from those Ulysses encountered during its first south polar pass in 1994 when solar activity, which is related to the magnetic behaviour of the Sun, was very low. Then, the solar wind at high latitudes was fast, but steady. This latest polar pass gives scientists the opportunity to learn just how different the polar regions of the Sun are at solar maximum compared with minimum. After spending four months above 70o south, Ulysses will swing towards the equator early next year to turn its attention to the northern hemisphere, beginning its passage over the north pole on 3 September 2001. Although it will be travelling the same path it followed six years ago, conditions will be quite different and new discoveries are eagerly awaited. Since launch in October 1990, Ulysses has already proved one of the most successful interplanetary missions ever. A joint ESA/NASA mission, it is the first spacecraft ever to be launched into an orbit outside the ecliptic, the plane in which the planets orbit the Sun. From this unique vantage point, it has changed our view of the heliosphere, the region of space filled by the solar wind and over which our Sun exerts its influence. At solar minimum, instruments on board Ulysses found that the fast solar wind, emanating from the Sun's poles, blows at a steady 750 km/s and fills a large fraction of the heliosphere. The state-of-the-art instruments were also able to show that the boundary between the fast wind and the slower, more variable wind from the equatorial regions, is surprisingly sharp. Another surprise was that the effects of collisions, occurring at low latitudes between fast and slow wind streams, continue to be felt all the way up to the poles. Ulysses discoveries, however, have not been confined to the Sun and heliosphere. Instruments on board the spacecraft also made the first ever measurements of dust particles and neutral helium atoms originating outside the solar system. These findings have

  18. Has the Sun Set on Quantum Dot- Sensitized Solar Cells?

    Directory of Open Access Journals (Sweden)

    Toshia L. Wrenn

    2015-05-01

    Full Text Available A reminder, a review and a look toward the future pros‐ pects for quantum dot-sensitized solar cells — a reminder of the highly viable, energy-efficient solar cells achievable; a review of ground-breaking devices and their similarities to the near unity photon-to-electron mechanisms of photosynthesis; a look toward architectures that capitalize on the advances observed in previous work.

  19. Proton activity of the Sun in current solar cycle 24

    CERN Document Server

    Li, Chuan; Fang, Cheng

    2014-01-01

    We present a study of 7 large solar proton events (SPEs) of current solar cycle 24 (from 2009 January up to date). They were recorded by GOES spacecraft with highest proton fluxes over 200 pfu for energies $>$10 MeV. In situ particle measurements show that: (1) The profiles of the proton fluxes are highly dependent of the locations of their solar sources, namely flares or coronal mass ejections (CMEs); (2) The solar particle release (SPR) times fall in the decay phase of the flare emission, and are in accordance with the times when the CMEs travel to an average height of 7.9 solar radii; (3) The time differences between the SPR and the flare peak are also dependent of the locations of the solar active regions (ARs). The results tend to support the concept of proton acceleration by the CME-driven shock, even though there exists a possibility of particle acceleration at flare site with subsequent perpendicular diffusion of accelerated particles in the interplanetary magnetic field (IMF). We derive the integral ...

  20. On the Path to SunShot - Emerging Opportunities and Challenges in Financing Solar

    Energy Technology Data Exchange (ETDEWEB)

    Feldham, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bolinger, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-05-01

    Financial innovations—independent of technology-cost improvements—could cut the cost of solar energy to customers and businesses by 30%–60% (see Feldman and Bolinger 2016). Financing is critical to solar deployment, because the costs of solar technologies are paid up front, while their benefits are realized over decades. Solar financing has been shaped by the government incentives designed to accelerate solar deployment. This is particularly true for federal tax incentives, which have spawned complex tax-equity structures that monetize tax benefits for project sponsors who otherwise could not use them efficiently. Although these structures have helped expand solar deployment, they are relatively costly and inefficient. This has spurred solar stakeholders to develop lower-cost financing solutions such as securitization of solar project portfolios, solar-specific loan products, and methods for incorporating residential PV’s value into home values. To move solar further toward an unsubsidized SunShot future, additional financial innovation must occur. Development of a larger, more mature U.S. solar industry will likely increase financial transparency and investor confidence, which in turn will enable simpler, lower-cost financing methods. Utility-scale solar might be financed more like conventional generation assets are today, non-residential solar might be financed more like a new roof, and residential solar might be financed more like an expensive appliance. Assuming a constant, SunShot-level installed PV system price, such financing innovations could reduce PV’s LCOE by an estimated 30%–60% (depending on the sector) compared with historical financing approaches.

  1. Insect thin films as sun blocks, not solar collectors.

    Science.gov (United States)

    Koon, D W; Crawford, A B

    2000-05-20

    We measured the visible reflectance spectra of whole wing sections from three species of iridescent butterflies and moths, for normal incidence, integrated over all reflected angles. In this manner, we separated the optics of the thin films causing the iridescence from the optics of the rest of the scale. We found that iridescence reduces solar absorption by the wing in all cases, typically by approximately 20% or less, in contrast to claims by Miaoulis and Heilman [Ann. Entomol. Soc. Am. 91, 122 (1998)] that the thin-film structures that produce iridescence act as solar collectors.

  2. 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

    2012-01-20

    Observations of comets in Sun-grazing orbits that survive solar insolation long enough to penetrate into the Sun's 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 C/2011 N3 (SOHO) within the low solar corona in five wavelength bands in the extreme ultraviolet (EUV). The comet penetrated to within 0.146 solar radius (~100,000 kilometers) of the solar surface before its EUV signal disappeared. Before that, material released into the coma--at first seen in absorption--formed a variable EUV-bright tail. During the final 10 minutes of observation by SDO's Atmospheric Imaging Assembly, ~6 × 10(8) to 6 × 10(10) grams of total mass was lost (corresponding to an effective nucleus diameter of ~10 to 50 meters), as estimated from the tail's deceleration due to interaction with the surrounding coronal material; the EUV absorption by the comet and the brightness of the tail suggest that the mass was at the high end of this range. These observations provide evidence that the nucleus had broken up into a family of fragments, resulting in accelerated sublimation in the Sun's intense radiation field.

  3. SunShot solar power reduces costs and uncertainty in future low-carbon electricity systems.

    Science.gov (United States)

    Mileva, Ana; Nelson, James H; Johnston, Josiah; Kammen, Daniel M

    2013-08-20

    The United States Department of Energy's SunShot Initiative has set cost-reduction targets of $1/watt for central-station solar technologies. We use SWITCH, a high-resolution electricity system planning model, to study the implications of achieving these targets for technology deployment and electricity costs in western North America, focusing on scenarios limiting carbon emissions to 80% below 1990 levels by 2050. We find that achieving the SunShot target for solar photovoltaics would allow this technology to provide more than a third of electric power in the region, displacing natural gas in the medium term and reducing the need for nuclear and carbon capture and sequestration (CCS) technologies, which face technological and cost uncertainties, by 2050. We demonstrate that a diverse portfolio of technological options can help integrate high levels of solar generation successfully and cost-effectively. The deployment of GW-scale storage plays a central role in facilitating solar deployment and the availability of flexible loads could increase the solar penetration level further. In the scenarios investigated, achieving the SunShot target can substantially mitigate the cost of implementing a carbon cap, decreasing power costs by up to 14% and saving up to $20 billion ($2010) annually by 2050 relative to scenarios with Reference solar costs.

  4. Robust optimal sun-pointing control of a large solar power satellite

    Science.gov (United States)

    Wu, Shunan; Zhang, Kaiming; Peng, Haijun; Wu, Zhigang; Radice, Gianmarco

    2016-10-01

    The robust optimal sun-pointing control strategy for a large geostationary solar power satellite (SPS) is addressed in this paper. The SPS is considered as a huge rigid body, and the sun-pointing dynamics are firstly proposed in the state space representation. The perturbation effects caused by gravity gradient, solar radiation pressure and microwave reaction are investigated. To perform sun-pointing maneuvers, a periodically time-varying robust optimal LQR controller is designed to assess the pointing accuracy and the control inputs. It should be noted that, to reduce the pointing errors, the disturbance rejection technique is combined into the proposed LQR controller. A recursive algorithm is then proposed to solve the optimal LQR control gain. Simulation results are finally provided to illustrate the performance of the proposed closed-loop system.

  5. Design and Implementation of PLC-Based Automatic Sun tracking System for Parabolic Trough Solar Concentrator

    Directory of Open Access Journals (Sweden)

    Wang Jinping

    2016-01-01

    Full Text Available A sun-tracking system for parabolic trough solar concentrators (PTCs is a control system used to orient the concentrator toward the sun always, so that the maximum energy can be collected. The work presented here is a design and development of PLC based sun tracking control system for PTC. Sun tracking control system consists of a Programmable Logic Controller (PLC and a single axis hydraulic drives tracking control system. Hydraulic drives and the necessary tracking angle algorithm have been designed and developed to perform the technical tasks. A PLC unit was employed to control and monitor the mechanical movement of the PTC and to collect and store data related to the tracking angle of PTC. It is found that the tracking error of the system is less than 0.6°. Field experience shows that tracking algorithm act stable and reliable and suit for PTCs.

  6. Here Comes the Sun! Residential Solar Systems Add up to Savings

    Science.gov (United States)

    Roman, Harry T.

    2007-01-01

    Every day, the sun showers the planet with millions of times more energy that its people use. The only problem is that the energy is spread out over the entire earth's surface and thus must be harvested. Engineers are learning to capture and use some of this energy to make electricity for homes. A well-designed solar system can last for 20 years…

  7. Solar radiation pressure used for formation flying control around the Sun-Earth libration point

    Institute of Scientific and Technical Information of China (English)

    Sheng-ping GONG; Jun-feng LI; He-xi BAOYIN

    2009-01-01

    Solar radiation pressure is used to control the formation flying around the L2 libration point in the Sun-Earth system. Formation flying control around a halo orbit requires a very small thrust that cannot be satisfied by the latest thrusters. The key contribution of this paper is that the continuous low thrust is produced by solar radiation pressure to achieve the tight formation flying around the libration point. However, only certain families of formation types can be controlled by solar radiation pressure since the direction of solar radiation pressure is restricted to a certain range. Two types of feasible formations using solar radiation pressure control are designed. The conditions of feasible formations are given analytically. Simulations are presented for each case, and the results show that the formations are well controlled by solar radiation pressure.

  8. Simulation of Quiet-Sun Hard X-Rays Related to Solar Wind Superhalo Electrons

    Science.gov (United States)

    Wang, Wen; Wang, Linghua; Krucker, Säm; Hannah, Iain

    2016-05-01

    In this paper, we propose that the accelerated electrons in the quiet Sun could collide with the solar atmosphere to emit Hard X-rays (HXRs) via non-thermal bremsstrahlung, while some of these electrons would move upwards and escape into the interplanetary medium, to form a superhalo electron population measured in the solar wind. After considering the electron energy loss due to Coulomb collisions and the ambipolar electrostatic potential, we find that the sources of the superhalo could only occur high in the corona (at a heliocentric altitude ≳ 1.9 R_{⊙} (the mean radius of the Sun)), to remain a power-law shape of electron spectrum as observed by Solar Terrestrial Relations Observatory (STEREO) at 1 AU near solar minimum (Wang et al. in Astrophys. J. Lett. 753, L23, 2012). The modeled quiet-Sun HXRs related to the superhalo electrons fit well to a power-law spectrum, f ˜ ɛ^{-γ} in the photon energy ɛ, with an index γ≈2.0 - 2.3 (3.3 - 3.7) at 10 - 100 keV, for the warm/cold-thick-target (thin-target) emissions produced by the downward-traveling (upward-traveling) accelerated electrons. These simulated quiet-Sun spectra are significantly harder than the observed spectra of most solar HXR flares. Assuming that the quiet-Sun sources cover 5 % of the solar surface, the modeled thin-target HXRs are more than six orders of magnitude weaker than the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) upper limit for quiet-Sun HXRs (Hannah et al. in Astrophys. J. 724, 487, 2010). Using the thick-target model for the downward-traveling electrons, the RHESSI upper limit restricts the number of downward-traveling electrons to at most {≈} 3 times the number of escaping electrons. This ratio is fundamentally different from what is observed during solar flares associated with escaping electrons where the fraction of downward-traveling electrons dominates by a factor of 100 to 1000 over the escaping population.

  9. PROCESSING METHOD EFFECT ON SUN DIAMETER MEASUREMENT WITH CCD SOLAR ASTROLABE

    Energy Technology Data Exchange (ETDEWEB)

    Djafer, Djelloul [Unite de Recherche Appliquee en Energies Renouvelables, BP 88, Ghardaiea (Algeria); Irbah, Abdenour, E-mail: djdjafer@gmail.com, E-mail: abdenour.irbah@latmos.ipsl.fr [Laboratoire Atmospheres, Milieux, Observations Spatiales (LATMOS), CNRS UMR8190, Universite Paris VI, Pierre et Marie Curie, Universite de Versailles Saint-Quentin-en-Yvelines INSU, 78280 Guyancourt (France)

    2012-05-01

    Photometric Sun diameter measurement is based on the calculation of the inflection point of the solar limb. In ground measurement, this point is located at a position on the solar limb where the signal-to-noise ratio is very high, which necessitates the appropriate filtering techniques to eliminate the noise while preserving its position. In this paper, we compare the filtering method currently in use to process the CCD solar astrolabe data, the FFTD method widely used, with a different method that we propose. Using the acquired data from the CCD astrolabe at Calern, France during 1997, we can obtain a mean difference of 130 mas in the measured radii.

  10. Planetary influence on the young Sun's evolution: the solar neutrino probe

    CERN Document Server

    Lopes, Ilidio

    2013-01-01

    Recent observations of solar twin stars with planetary systems like the Sun, have uncovered that these present a peculiar surface chemical composition. This is believed to be related to the formation of earth-like planets. This suggests that twin stars have a radiative interior that is richer in heavy elements than their envelopes. Moreover, the current standard solar model does not fully agree with the helioseismology data and solar neutrino flux measurements. In this work, we find that this agreement can improve if the Sun has mass loss during the pre-main sequence, as was previously shown by other groups. Despite this better agreement, the internal composition of the Sun is still uncertain, especially for elements heavier than helium. With the goal of inferring the chemical abundance of the solar interior, we tested several chemical compositions. We found that heavy element abundances influence the sound speed and solar neutrinos equally. Nevertheless, the carbon-nitrogen-oxygen (CNO;13N, 15O and 17F) neut...

  11. Marshall Space Flight Center's Solar Wind Facility

    Science.gov (United States)

    Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Whittlesey, P. L.

    2017-01-01

    Historically, NASA's Marshall Space Flight Center (MSFC) has operated a Solar Wind Facility (SWF) to provide long term particle and photon exposure to material samples. The requirements on the particle beam details were not stringent as the cumulative fluence level is the test goal. Motivated by development of the faraday cup instrument on the NASA Solar Probe Plus (SPP) mission, the MSFC SWF has been upgraded to included high fidelity particle beams providing broadbeam ions, broadbeam electrons, and narrow beam protons or ions, which cover a wide dynamic range of solar wind velocity and flux conditions. The large vacuum chamber with integrated cryo-shroud, combined with a 3-axis positioning system, provides an excellent platform for sensor development and qualification. This short paper provides some details of the SWF charged particle beams characteristics in the context of the Solar Probe Plus program requirements. Data will be presented on the flux and energy ranges as well as beam stability.

  12. Performance of an electro-optical solar compass in partially obscured Sun conditions.

    Science.gov (United States)

    Bollanti, S; De Meis, D; Di Lazzaro, P; Flora, F; Gallerano, G P; Mezi, L; Murra, D; Vicca, D

    2016-04-20

    Solar compasses are designed to accurately find true North on sunny days. However, no data on their performance are available when sunlight is partially blocked, e.g., by a cloud. We have measured, for the first time to the best of our knowledge, the performance of one of the most accurate electro-optical solar compasses (accuracy better than 0.01  deg) as a function of the solar disk obscuration during the Sun's eclipse on 20 March 2015. The measurements show that the accuracy level is mainly dependent on the asymmetry of the obscuration with respect to the main axis of the optical detection system and, to a lesser extent, on the percentage of the solar disk covered. In particular, azimuth measurement suffered a maximum deviation of 0.08 deg when 35% of the solar disk was asymmetrically obscured. The deviation was smaller when 46% of the solar disk was more symmetrically obscured. This experiment demonstrates that, even in the case of a partially obscured Sun, the electro-optical solar compass maintains an accuracy better than magnetic and electronic compasses.

  13. Maximizing Output Power of a Solar Panel via Combination of Sun Tracking and Maximum Power Point Tracking by Fuzzy Controllers

    OpenAIRE

    Mohsen Taherbaneh; A. H. Rezaie; H. Ghafoorifard; Rahimi, K; M. B. Menhaj

    2010-01-01

    In applications with low-energy conversion efficiency, maximizing the output power improves the efficiency. The maximum output power of a solar panel depends on the environmental conditions and load profile. In this paper, a method based on simultaneous use of two fuzzy controllers is developed in order to maximize the generated output power of a solar panel in a photovoltaic system: fuzzy-based sun tracking and maximum power point tracking. The sun tracking is performed by changing the solar...

  14. General formula for on-axis sun-tracking system and its application in improving tracking accuracy of solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Chong, K.K.; Wong, C.W. [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Off Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur (Malaysia)

    2009-03-15

    Azimuth-elevation and tilt-roll tracking mechanism are among the most commonly used sun-tracking methods for aiming the solar collector towards the sun at all times. It has been many decades that each of these two sun-tracking methods has its own specific sun-tracking formula and they are not interrelated. In this paper, the most general form of sun-tracking formula that embraces all the possible on-axis tracking methods is presented. The general sun-tracking formula not only can provide a general mathematical solution, but more significantly it can improve the sun-tracking accuracy by tackling the installation error of the solar collector. (author)

  15. Modelling the drying kinetics of green peas in a solar dryer and under open sun

    Energy Technology Data Exchange (ETDEWEB)

    Sunil [Department of Mechanical Engineering, BRCM CET Bahal, Haryana–127028 (India); Varun [Department of Mechanical Engineering, NIT Hamirpur, (H.P.)–177005 (India); Sharma, Naveen [Department of Mechanical and Industrial Engineering, IITR, (U.K.)–247667 (India)

    2013-07-01

    The drying kinetics of green peas was investigated in an indirect solar dryer and under open sun. The entire drying process took place exclusively in falling rate period. The constant rate period was absent from the drying curves. The rehydration capacity was also determined for peas dried in solar dryer and under open sun. The rehydration capacity of solar dried peas was found higher than open sun dried peas. The drying data obtained from experiments were fitted to eight different mathematical models. The performance of these models was examined by comparing the coefficient of correlation (R2), sum of squares error (SSE), mean squared error (MSE) and root mean square error (RMSE) between observed and predicted values of moisture ratios. Among these models, the thin layer drying model developed by Page showed good agreement with the data obtained from experiments for bottom tray. The Midilli et al. model has shown better fit to the experimental data for top tray and open sun than other models.

  16. Modelling the drying kinetics of green peas in a solar dryer and under open sun

    Directory of Open Access Journals (Sweden)

    Sunil, Varun, Naveen Sharma

    2013-01-01

    Full Text Available The drying kinetics of green peas was investigated in an indirect solar dryer and under open sun. The entire drying process took place exclusively in falling rate period. The constant rate period was absent from the drying curves. The rehydration capacity was also determined for peas dried in solar dryer and under open sun. The rehydration capacity of solar dried peas was found higher than open sun dried peas. The drying data obtained from experiments were fitted to eight different mathematical models. The performance of these models was examined by comparing the coefficient of correlation (R2, sum of squares error (SSE, mean squared error (MSE and root mean square error (RMSE between observed and predicted values of moisture ratios. Among these models, the thin layer drying model developed by Page showed good agreement with the data obtained from experiments for bottom tray. The Midilli et al. model has shown better fit to the experimental data for top tray and open sun than other models.

  17. Protección solar (Sun Proof)

    Centers for Disease Control (CDC) Podcasts

    2012-10-23

    En este podcast, los niños de Kidtastics hablan sobre los efectos dañinos del sol y cómo protegerse.  Created: 10/23/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 12/11/2013.

  18. The oxygen isotopic composition of the Sun inferred from captured solar wind.

    Science.gov (United States)

    McKeegan, K D; Kallio, A P A; Heber, V S; Jarzebinski, G; Mao, P H; Coath, C D; Kunihiro, T; Wiens, R C; Nordholt, J E; Moses, R W; Reisenfeld, D B; Jurewicz, A J G; Burnett, D S

    2011-06-24

    All planetary materials sampled thus far vary in their relative abundance of the major isotope of oxygen, (16)O, such that it has not been possible to define a primordial solar system composition. We measured the oxygen isotopic composition of solar wind captured and returned to Earth by NASA's Genesis mission. Our results demonstrate that the Sun is highly enriched in (16)O relative to the Earth, Moon, Mars, and bulk meteorites. Because the solar photosphere preserves the average isotopic composition of the solar system for elements heavier than lithium, we conclude that essentially all rocky materials in the inner solar system were enriched in (17)O and (18)O, relative to (16)O, by ~7%, probably via non-mass-dependent chemistry before accretion of the first planetesimals.

  19. The Solar Solution: Tracking the Sun with Low Energy Neutrinos

    CERN Document Server

    Hartman, Nicole

    2016-01-01

    As neutrinos become a significant background for projected dark matter experiments, the community will become concerned with determining if events counted in a dark matter experiment are good dark matter candidates or low-energy neutrinos from astrophysical sources. We investigate the feasibility of using neutrino-electron scattering in a terrestrial detector medium as a means to determine the flight direction of the original, low-energy solar neutrino.Using leading-order weak interactions in the Standard Model and constrains from energy and momentum conservation, we developed a simple simulation that suggests that 68% of the time the ejected electron would be within 0.99 radians of the incident neutrino's direction. This suggests that it may be fruitful to pursue low-energy neutrino detection capability that can utilize such ejected electrons.

  20. Rieger-type periodicities on the Sun and the Earth during solar cycles 21 and 22

    Science.gov (United States)

    Silva, H. G.; Lopes, I.

    2017-03-01

    Rieger-type periods of the magnetic sunspot area time series have been found in two atmospheric time-series variables: neutron monitor count rate and atmospheric electric potential gradient. The data considered comprises two solar cycles (21, 22) and spans from 1978 to 1990. The study reveals the existence of similar and correlated features in sunspot area as well as neutron counts and atmospheric electric potential gradient, favoring the possibility that the Sun's activity affects the Earth's atmosphere and weather at a time scale between 150-300 days. Moreover, five different Rieger-type periods in the sunspot area time series are found, four of which are detected in the neutron monitor count rate, and three in the atmospheric electric potential gradient. These values are consistent with the periods predicted for stationary solar Rossby waves existing inside the Sun. The possibility is discussed that instabilities on the solar magnetic field caused by solar Rossby waves in the Sun's interior might indirectly be affecting the activity of the heliosphere and the Earth's atmosphere.

  1. Catawba Science Center solar activities. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1983-01-01

    Two demonstration solar water heaters were built. One was to be used at the Science Center and the other with traveling programs. This was completed and both units are being used for these programs which continue. We were able to build a library of 99 solar energy books and booklets that are available to the public for reference. We also conducted programs for 683 students of all ages. The culminating activity was the planned Energy Awareness Festival. This was held on September 26, 1981 and attracted 450 area citizens. We offered free exhibit space and hosted 17 exhibitors.

  2. Solar Energy Research Center Instrumentation Facility

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Thomas, J.; Papanikolas, John, P.

    2011-11-11

    SOLAR ENERGY RESEARCH CENTER INSTRUMENTATION FACILITY The mission of the Solar Energy Research Center (UNC SERC) at the University of North Carolina at Chapel Hill (UNC-CH) is to establish a world leading effort in solar fuels research and to develop the materials and methods needed to fabricate the next generation of solar energy devices. We are addressing the fundamental issues that will drive new strategies for solar energy conversion and the engineering challenges that must be met in order to convert discoveries made in the laboratory into commercially available devices. The development of a photoelectrosynthesis cell (PEC) for solar fuels production faces daunting requirements: (1) Absorb a large fraction of sunlight; (2) Carry out artificial photosynthesis which involves multiple complex reaction steps; (3) Avoid competitive and deleterious side and reverse reactions; (4) Perform 13 million catalytic cycles per year with minimal degradation; (5) Use non-toxic materials; (6) Cost-effectiveness. PEC efficiency is directly determined by the kinetics of each reaction step. The UNC SERC is addressing this challenge by taking a broad interdisciplinary approach in a highly collaborative setting, drawing on expertise across a broad range of disciplines in chemistry, physics and materials science. By taking a systematic approach toward a fundamental understanding of the mechanism of each step, we will be able to gain unique insight and optimize PEC design. Access to cutting-edge spectroscopic tools is critical to this research effort. We have built professionally-staffed facilities equipped with the state-of the-art instrumentation funded by this award. The combination of staff, facilities, and instrumentation specifically tailored for solar fuels research establishes the UNC Solar Energy Research Center Instrumentation Facility as a unique, world-class capability. This congressionally directed project funded the development of two user facilities: TASK 1: SOLAR

  3. Selections from 2016: A Connection Between Solar Explosions and Dimming on the Sun

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    Editors note:In these last two weeks of 2016, well be looking at a few selections that we havent yet discussed on AAS Nova from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume after the AAS winter meeting.The Nature of CME-Flare-Associated Coronal DimmingPublished June2016Main takeaway:The Solar Dynamics Observatory (SDO) observed a large solar eruption at the end of December 2011. Scientists Jianxia Cheng (Shanghai Astronomical Observatory and the Chinese Academy of Sciences) and Jiong Qiu (Montana State University) studied this coronal mass ejection and the associated flaring on the Suns surface. They found that this activity was accompanied by dimming in the Suns corona near the ends of the flare ribbons.Why its interesting:The process of coronal dimming isnt fully understood, but Cheng and Qius observations provide a clear link between coronal dimming and eruptions of plasma and energy from the Sun. The locations of the dimming the footpoints of the two flare ribbons and the timing relative to the eruption suggests that coronal dimming is caused by the ejection of hot plasma from the Suns surface.How this process was studied:There are a number of satellites dedicated to observing the Sun, and several of them were used to study this explosion. Data from SDOs Atmospheric Imaging Assembly (which images in extreme ultraviolet) and its Helioseismic and Magnetic Imager (which measures magnetic fields) were used as well as observations from STEREO, the pair of satellites orbiting the Sun at 90 from SDO.CitationJ. X. Cheng and J. Qiu 2016 ApJ 825 37. doi:10.3847/0004-637X/825/1/37

  4. Global helioseismology (WP4.1): From the Sun to the stars & solar analogs

    CERN Document Server

    Garcia, Rafael A

    2016-01-01

    Sun-as-a star observations put our star as a reference for stellar observations. Here, I review the activities in which the SPACEINN global seismology team (Working Package WP4.1) has worked during the past 3 years. In particular, we will explain the new deliverables available on the SPACEINN seismic+ portal. Moreover, special attention will be given to surface dynamics (rotation and magnetic fields). After characterizing the rotation and the magnetic properties of around 300 solar-like stars and defining proper metrics for that, we use their seismic properties to characterize 18 solar analogues for which we study their surface magnetic and seismic properties. This allows us to put the Sun into context compared to its siblings.

  5. Transport Phenomena and Light Element Abundances in the Sun and Solar Type Stars

    CERN Document Server

    Vauclair, S

    2000-01-01

    The observations of light elements in the Sun and Solar type stars givespecial clues for understanding the hydrodynamical processes at work in stellarinteriors. In the Sun 7Li is depleted by 140 while 3He has not increased bymore than 10 0n 3 Gyrs. Meanwhile the inversion of helioseismic modes lead toa precision on the sound velocity of about .1The mixing processes below thesolar convection zone are constrained by these observations. Lithium isdepleted in most Pop I solar type stars. In halo stars however, the lithiumabundance seems constant in the "spite plateau" with no observed dispersion,which is difficult to reconcile with the theory of diffusion processes. In thepresent paper, the various relevant observations will be discussed. It will beshown that the mu-gradients induced by element settling may help solving the"lithium paradox".

  6. Optimal sun-alignment techniques of large solar arrays in electric propulsion spacecraft

    Science.gov (United States)

    Meissinger, H. F.; Dailey, C. L.; Valgora, M. E.

    1982-01-01

    Optimum sun-alignment of large solar arrays in electric propulsion spacecraft operating in earth orbit requires periodic roll motions around the thrust axis, synchronized with the apparent conical motion of the sun line. This oscillation is sustained effectively with the aid of gravity gradient torques while only a small share of the total torque is being contributed by the attitude control system. Tuning the system for resonance requires an appropriate choice of moment-of-inertia characteristics. To minimize atmospheric drag at low orbital altitudes the solar array is oriented parallel, or nearly parallel, to the flight direction. This can increase the thrust-to-drag ratio by as much as an order of magnitude. Coupled with optimal roll orientation, this feathering technique will permit use of electric propulsion effectively at low altitudes in support of space shuttle or space station activities and in spiral ascent missions.

  7. THE MAJOR GEOEFFECTIVE SOLAR ERUPTIONS OF 2012 MARCH 7: COMPREHENSIVE SUN-TO-EARTH ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Patsourakos, S.; Nindos, A.; Kouloumvakos, A. [University of Ioannina, Department of Physics, Section of Astrogeophysics, Ioannina (Greece); Georgoulis, M. K.; Gontikakis, C.; Moraitis, K.; Syntelis, P. [Research Center for Astronomy and Applied Mathematics, Academy of Athens, Athens (Greece); Vourlidas, A. [Space Physics Division, Applied Physics Laboratory, Johns Hopkins University, Laurel, MD (United States); Sarris, T.; Anagnostopoulos, G.; Iliopoulos, A. C.; Pavlos, G.; Sarafopoulos, D. [Democritus University of Thrace, Department of Electrical and Computer Engineering, Xanthi (Greece); Anastasiadis, A.; Tsironis, C. [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece); Chintzoglou, G. [School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 6A2, Fairfax, VA 22030 (United States); Daglis, I. A.; Katsavrias, C. [Department of Physics, University of Athens (Greece); Hatzigeorgiu, N. [University of California, Berkeley, Space Sciences Laboratory, Berkeley, CA 94720-7450 (United States); Nieves-Chinchilla, T. [IACS/CUA at NASA Goddard Space Flight Center Heliospheric Physics Lab, Greenbelt, MD 20771 (United States); and others

    2016-01-20

    During the interval 2012 March 7–11 the geospace experienced a barrage of intense space weather phenomena including the second largest geomagnetic storm of solar cycle 24 so far. Significant ultra-low-frequency wave enhancements and relativistic-electron dropouts in the radiation belts, as well as strong energetic-electron injection events in the magnetosphere were observed. These phenomena were ultimately associated with two ultra-fast (>2000 km s{sup −1}) coronal mass ejections (CMEs), linked to two X-class flares launched on early 2012 March 7. Given that both powerful events originated from solar active region NOAA 11429 and their onsets were separated by less than an hour, the analysis of the two events and the determination of solar causes and geospace effects are rather challenging. Using satellite data from a flotilla of solar, heliospheric and magnetospheric missions a synergistic Sun-to-Earth study of diverse observational solar, interplanetary and magnetospheric data sets was performed. It was found that only the second CME was Earth-directed. Using a novel method, we estimated its near-Sun magnetic field at 13 R{sub ⊙} to be in the range [0.01, 0.16] G. Steep radial fall-offs of the near-Sun CME magnetic field are required to match the magnetic fields of the corresponding interplanetary CME (ICME) at 1 AU. Perturbed upstream solar-wind conditions, as resulting from the shock associated with the Earth-directed CME, offer a decent description of its kinematics. The magnetospheric compression caused by the arrival at 1 AU of the shock associated with the ICME was a key factor for radiation-belt dynamics.

  8. Development of a microprocessor-based Sun-tracking system for solar collectors

    Science.gov (United States)

    Kohler, S. M.; Wilcoxen, J. L.

    1980-04-01

    The development of a prototype Sun-tracking system and the tests performed on it on an east-west trough solar collector array are described. The system includes a controller built around an RCA1802 microprocessor, a digital shaft encoder, and a heat flux sensor. The heat flux sensor consists of a fine resistance wire wrapped around the receiver tube. The wire is used to correct errors in calculated tracking angles arising from reflector imperfections and misalignments.

  9. Development of a microprocessor-based sun-tracking system for solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, S.M.; Wilcoxen, J.L.

    1980-04-01

    The development of a prototype sun-tracking system and the tests performed on it on an east-west trough solar collector array are described. The system includes a controller built around an RCA1802 microprocessor (..mu..P), a digital shaft encoder, and a heat flux sensor. The heat flux sensor consists of a fine resistance wire wrapped around the receiver tube. The wire is used to correct errors in calculated tracking angles arising from reflector imperfections and misalignments.

  10. USING REALISTIC MHD SIMULATIONS FOR THE MODELING AND INTERPRETATION OF QUIET-SUN OBSERVATIONS WITH THE SOLAR DYNAMICS OBSERVATORY HELIOSEISMIC AND MAGNETIC IMAGER

    Energy Technology Data Exchange (ETDEWEB)

    Kitiashvili, I. N. [NASA Ames Research Center, Moffett Field, Mountain View, CA 94035 (United States); Couvidat, S. [Stanford University, Stanford, CA 94305 (United States); Lagg, A. [Max Planck Institute for Solar System Research, Göttingen, D-37077 (Germany)

    2015-07-20

    The solar atmosphere is extremely dynamic, and many important phenomena develop on small scales that are unresolved in observations with the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory. For correct calibration and interpretation of the observations, it is very important to investigate the effects of small-scale structures and dynamics on the HMI observables, such as Doppler shift, continuum intensity, spectral line depth, and width. We use 3D radiative hydrodynamics simulations of the upper turbulent convective layer and the atmosphere of the Sun, and a spectro-polarimetric radiative transfer code to study observational characteristics of the Fe i 6173 Å line observed by HMI in quiet-Sun regions. We use the modeling results to investigate the sensitivity of the line Doppler shift to plasma velocity, and also sensitivities of the line parameters to plasma temperature and density, and determine effective line formation heights for observations of solar regions located at different distances from the disk center. These estimates are important for the interpretation of helioseismology measurements. In addition, we consider various center-to-limb effects, such as convective blueshift, variations of helioseismic travel-times, and the “concave” Sun effect, and show that the simulations can qualitatively reproduce the observed phenomena, indicating that these effects are related to a complex interaction of the solar dynamics and radiative transfer.

  11. Minimum time solar sailing from geosynchronous orbit to the sun-earth L2 point

    Science.gov (United States)

    Hur, Sun H.; Bryson, Arthur E., Jr.

    1992-08-01

    An approximate time-optimal of a solar sail from a geosynchronous orbit to the sun-earth L2 libration point is found using a combined method of local optimization and single shooting. The local optimization strategy is based on maximizing the time rate of change of an energy variable at each time. This strategy overcomes the numerical difficulties associated with solving optimal control problems of long duration like the solar sail transfer problem. The single shooting portion of the method is employed to meet the terminal constraints. The combined method can be applied to other optimal low thrust transfer problems of long duration.

  12. Simplification of Sun Tracking Mode to Gain High Concentration Solar Energy

    Directory of Open Access Journals (Sweden)

    Omar Aliman

    2007-01-01

    Full Text Available Power conversion from solar thermal energy to electrical energy is still very cost-intensive. Serious effort has to be given in the development of the concentrator or heliostat structure expenditure which contributing the most expensive component in a central receiver solar power plant. With current development to find alternatives and lower down the capital, a new mode of sun tracking has been developed and feasibility tested. As it applies a single stage collector replacing conventional double stages structure, the new technique has significantly benefits use in high temperature and high concentration solar energy applications. Meanwhile, the stationary or fixed target (receiver offers more convenient working environment for various applications. Large and heavy solar powered Stirling Engine could be placed at the stationary location. On the other advantage offers by the new technique, the optical alignment was reasonably easier and less time consuming.

  13. Axion mechanism of the Sun luminosity and solar dynamo - geodynamo connection

    CERN Document Server

    Rusov, V D; Kudela, K; Mavrodiev, S Cht; Sharph, I V; Zelentsova, T N; Smolyar, V P; Merkotan, K K

    2010-01-01

    We show existence of strong negative correlation between the temporal varia-tions of magnetic field toroidal component of the solar tachocline (the bottom of convective zone) and the Earth magnetic field (Y-component). The possibility that hypothetical solar axions, which can transform into photons in external electric or magnetic fields (the inverse Primakoff effect), can be the instrument by which the magnetic field of convective zone of the Sun modulates the magnetic field of the Earth is considered. We propose the axion mechanism of Sun luminosity and "solar dynamo - geodynamo" connection, where an energy of solar axions emitted in M1 transition in 57Fe nuclei is modulated at first by the magnetic field of the solar tachocline zone (due to the inverse coherent Primakoff effect) and after that is resonance absorbed in the core of the Earth, thereby playing the role of an energy source and a modulator of the Earth magnetic field. Within the framework of this mechanism estimations of the strength of an axion...

  14. The Sun's X-ray Emission During the Recent Solar Minimum

    Science.gov (United States)

    Sylwester, Janusz; Kowalinski, Mirek; Gburek, Szymon; Siarkowski, Marek; Kuzin, Sergey; Farnik, Frantisek; Reale, Fabio; Phillips, Kenneth J. H.

    2010-02-01

    The Sun recently underwent a period of a remarkable lack of major activity such as large flares and sunspots, without equal since the advent of the space age a half century ago. A widely used measure of solar activity is the amount of solar soft X-ray emission, but until recently this has been below the threshold of the X-ray-monitoring Geostationary Operational Environmental Satellites (GOES). There is thus an urgent need for more sensitive instrumentation to record solar X-ray emission in this range. Anticipating this need, a highly sensitive spectrophotometer called Solar Photometer in X-rays (SphinX) was included in the solar telescope/spectrometer TESIS instrument package on the third spacecraft in Russia's Complex Orbital Observations Near-Earth of Activity of the Sun (CORONAS-PHOTON) program, launched 30 January 2009 into a near-polar orbit. SphinX measures X-rays in a band similar to the GOES longer-wavelength channel.

  15. A comparative study of Solar-Heliospheric Observations during very active Sun intervals in the 21st and 23rd solar cycles (April 1979 and March-April, 2001)

    Science.gov (United States)

    Berdichevsky, D. B.; Farrugia, C. J.; Lepping, R. P.; Richardson, I. G.; Galvin, A. B.; Schwenn, R.; Reames, D. V.

    2002-05-01

    On March 24, 2001, the largest sun spot group in 10 years, consisting of three or more active regions (ARs) centered near AR 9393, emerged from behind the eastern limb of the Sun and began a 2-week passage across the visible hemisphere. During the same time, the Sun showed several other ARs so this period constituted a phase of unusually intense solar activity that continued almost 18 days beyond the disk passage of the largest sun spot group and included possibly the most energetic solar flare event in modern records (a > X20 flare in soft X-rays). We shall present an overview of the associated solar energetic particle events and an analysis of the thermodynamic characteristics of the shocks observed in the Earth's vicinity. The investigation includes cross-correlation analysis of interplanetary plasma and magnetic field observations at ACE (SWEPAM/MAG level-2 data) situated 250 Re upstream of Earth and at Wind (SWE/MFI data), which was ahead of Earth and executing a distant prograde orbit with large Y-coordinate. The interval under study bears a close resemblance to a similar active period during April 1979 (i.e., 2 solar cycles earlier) observed by the Helios 1/2 probes and Earth solar wind monitors (ISEE-3, IMP). The similarities and differences between the two intervals are examined further.

  16. Calibration development strategies for the Daniel K. Inouye Solar Telescope (DKIST) data center

    Science.gov (United States)

    Watson, Fraser T.; Berukoff, Steven J.; Hays, Tony; Reardon, Kevin; Speiss, Daniel J.; Wiant, Scott

    2016-07-01

    The Daniel K. Inouye Solar Telescope (DKIST), currently under construction on Haleakalā, in Maui, Hawai'i will be the largest solar telescope in the world and will use adaptive optics to provide the highest resolution view of the Sun to date. It is expected that DKIST data will enable significant and transformative discoveries that will dramatically increase our understanding of the Sun and its effects on the Sun-Earth environment. As a result of this, it is a priority of the DKIST Data Center team at the National Solar Observatory (NSO) to be able to deliver timely and accurately calibrated data to the astronomical community for further analysis. This will require a process which allows the Data Center to develop calibration pipelines for all of the facility instruments, taking advantage of similarities between them, as well as similarities to current generation instruments. There will also be a challenges which are addressed in this article, such as the large volume of data expected, and the importance of supporting both manual and automated calibrations. This paper will detail the current calibration development strategies being used by the Data Center team at the National Solar Observatory to manage this calibration effort, so as to ensure delivery of high quality scientific data routinely to users.

  17. Simulation of Quiet-Sun Hard X-rays Related to Solar Wind Superhalo Electrons

    CERN Document Server

    Wang, Wen; Krucker, Sam; Hannah, Iain

    2016-01-01

    In this paper, we propose that the accelerated electrons in the quiet Sun could collide with the solar atmosphere to emit Hard X-rays (HXRs) via non-thermal bremsstrahlung, while some of these electrons would move upwards and escape into the interplanetary medium, to form a superhalo electron population measured in the solar wind. After considering the electron energy loss due to Coulomb collisions and the ambipolar electrostatic potential, we find that the sources of the superhalo could only occur high in the corona (at a heliocentric altitude $\\gtrsim 1.9$ R$_\\odot$ (the mean radius of the Sun)), to remain a power-law shape of electron spectrum as observed by STEREO at 1AU near solar minimum (Wang et al., 2012). The modeled quiet-Sun HXRs related to the superhalo electrons fit well to a power-law spectrum, $f \\sim \\varepsilon^{-\\gamma}$, with an index $\\gamma$ $\\approx$ 2.0 - 2.3 (3.3 - 3.7) at 10 - 100 keV, for the warm/cold thick-target (thin-target) emissions produced by the downward-traveling (upward-tr...

  18. Harnessing Sun's Energy with Quantum Dots Based Next Generation Solar Cell.

    Science.gov (United States)

    Halim, Mohammad A

    2012-12-27

    Our energy consumption relies heavily on the three components of fossil fuels (oil, natural gas and coal) and nearly 83% of our current energy is consumed from those sources. The use of fossil fuels, however, has been viewed as a major environmental threat because of their substantial contribution to greenhouse gases which are responsible for increasing the global average temperature. Last four decades, scientists have been searching for alternative sources of energy which need to be environmentally clean, efficient, cost-effective, renewable, and sustainable. One of the promising sustainable sources of energy can be achieved by harnessing sun energy through silicon wafer, organic polymer, inorganic dye, and quantum dots based solar cells. Among them, quantum dots have an exceptional property in that they can excite multiple electrons using only one photon. These dots can easily be synthesized, processed in solution, and incorporated into solar cell application. Interestingly, the quantum dots solar cells can exceed the Shockley-Queisser limit; however, it is a great challenge for other solar cell materials to exceed the limit. Theoretically, the quantum dots solar cell can boost the power conversion efficiency up to 66% and even higher to 80%. Moreover, in changing the size of the quantum dots one can utilize the Sun's broad spectrum of visible and infrared ranges. This review briefly overviews the present performance of different materials-based solar cells including silicon wafer, dye-sensitized, and organic solar cells. In addition, recent advances of the quantum dots based solar cells which utilize cadmium sulfide/selenide, lead sulfide/selenide, and new carbon dots as light harvesting materials has been reviewed. A future outlook is sketched as to how one could improve the efficiency up to 10% from the current highest efficiency of 6.6%.

  19. A Look into the Hellish Cradles of Suns and Solar Systems

    Science.gov (United States)

    2009-09-01

    New images released today by ESO delve into the heart of a cosmic cloud, called RCW 38, crowded with budding stars and planetary systems. There, young stars bombard fledgling suns and planets with powerful winds and blazing light, helped in their task by short-lived, massive stars that explode as supernovae. In some cases, this onslaught cooks away the matter that may eventually form new solar systems. Scientists think that our own Solar System emerged from such an environment. The dense star cluster RCW 38 glistens about 5500 light years away in the direction of the constellation Vela (the Sails). Like the Orion Nebula Cluster, RCW 38 is an "embedded cluster", in that the nascent cloud of dust and gas still envelops its stars. Astronomers have determined that most stars, including the low mass, reddish ones that outnumber all others in the Universe, originate in these matter-rich locations. Accordingly, embedded clusters provide scientists with a living laboratory in which to explore the mechanisms of star and planetary formation. "By looking at star clusters like RCW 38, we can learn a great deal about the origins of our Solar System and others, as well as those stars and planets that have yet to come", says Kim DeRose, first author of the new study that appears in the Astronomical Journal. DeRose did her work on RCW 38 as an undergraduate student at the Harvard-Smithsonian Center for Astrophysics, USA. Using the NACO adaptive optics instrument on ESO's Very Large Telescope [1], astronomers have obtained the sharpest image yet of RCW 38. They focused on a small area in the centre of the cluster that surrounds the massive star IRS2, which glows in the searing, white-blue range, the hottest surface colour and temperatures possible for stars. These dramatic observations revealed that IRS2 is actually not one, but two stars - a binary system consisting of twin scorching stars, separated by about 500 times the Earth-Sun distance. In the NACO image, the astronomers

  20. SunShot Vision Study: A Comprehensive Analysis of the Potential for U.S. Solar Electricity Generation (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-06-01

    The SunShot Vision Study provides the most comprehensive assessment to date of the potential for solar technologies to meet a significant share of electricity demand in the United States during the next several decades.

  1. SUN-LIKE MAGNETIC CYCLES IN THE RAPIDLY ROTATING YOUNG SOLAR ANALOG HD 30495

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Ricky [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States); Metcalfe, Travis S. [Space Science Institute, 4750 Walnut St. Suite 205, Boulder, CO 80301 (United States); Hall, Jeffrey C. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Henry, Gregory W., E-mail: egeland@ucar.edu [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States)

    2015-10-10

    A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial (∼2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has an unusual evolutionary history. In this work, we present new and archival observations of dual magnetic cycles in the young solar analog HD 30495, a ∼1 Gyr old G1.5 V star with a rotation period near 11 days. This star falls squarely on the relationships established by the broader stellar sample, with short-period variations at ∼1.7 years and a long cycle of ∼12 years. We measure three individual long-period cycles and find durations ranging from 9.6 to 15.5 years. We find the short-term variability to be intermittent, but present throughout the majority of the time series, though its occurrence and amplitude are uncorrelated with the longer cycle. These essentially solar-like variations occur in a Sun-like star with more rapid rotation, though surface differential rotation measurements leave open the possibility of a solar equivalence.

  2. Why is the Sun No Longer Accelerating Particles to High Energy in Solar Cycle 24?

    Science.gov (United States)

    Mewaldt, R. A.; Cohen, C. M.; Li, G.; Mason, G. M.; Smith, C. W.; von Rosenvinge, T. T.; Vourlidas, A.

    2015-12-01

    Why is the Sun No Longer Accelerating Particles to High Energy in Solar Cycle 24?Measurements by ACE, STEREO, and GOES show that the number of large Solar Energetic Particle (SEP) events in solar cycle 24 is reduced by a factor of ~2 compared to this point of solar cycle 23, while the fluences of >10 MeV/nuc ions from H to Fe are reduced by factors ranging from ~4 to ~10. Compared to solar Cycle 22 and 23, the fluence of >100 MeV protons is reduced by factors of ~7 to ~10 in the current cycle. A common element of these observations is that the observed Cycle-24 energy spectra have "breaks" that suddenly steepen 2 to 4 times lower in energy/nucleon than in Cycle 23. We investigate the origin of these cycle-to-cycle spectral differences by evaluating possible factors that control the maximum energy of CME-shock-accelerated particles in the two cycles, including seed-particle densities of suprathermal ions, the interplanetary magnetic field strength and turbulence level, and properties of the associated CMEs. The effect of these conditions will be evaluated in the context of existing SEP acceleration models by comparing SEP data with simulations and with analytic evaluations of the maximum kinetic energy to which CME shocks can accelerate solar energetic ions from H to Fe. Understanding the properties that control the maximum kinetic energy of CME-shock accelerated particles has important implications for predicting future solar activity.

  3. A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun: I. Atmospheric parameters and color similarity to the Sun

    CERN Document Server

    de Mello, G F Porto; da Silva, L; de Nader, R V

    2013-01-01

    Solar twins and analogs are fundamental in the characterization of the Sun's place in the context of stellar measurements, as they are in understanding how typical the solar properties are in its neighborhood. They are also important for representing sunlight observable in the night sky for diverse photometric and spectroscopic tasks, besides being natural candidates for harboring planetary systems similar to ours and possibly even life-bearing environments. We report a photometric and spectroscopic survey of solar twin stars within 50 pc of the Sun. Hipparcos absolute magnitudes and (B-V)_Tycho colors were used to define a 2 sigma box around the solar values, where 133 stars were considered. Additional stars resembling the solar UBV colors in a broad sense, plus stars present in the lists of Hardorp, were also selected. All objects were ranked by a color-similarity index with respect to the Sun, defined by uvby and BV photometry. Moderately high-resolution, high-S/N spectra were used for a subsample of equat...

  4. The evolution of the Sun's birth cluster and the search for the solar siblings with Gaia

    Science.gov (United States)

    Martínez-Barbosa, C. A.; Brown, A. G. A.; Boekholt, T.; Portegies Zwart, S.; Antiche, E.; Antoja, T.

    2016-03-01

    We use self-consistent numerical simulations of the evolution and disruption of the Sun's birth cluster in the Milky Way potential to investigate the present-day phase-space distribution of the Sun's siblings. The simulations include the gravitational N-body forces within the cluster and the effects of stellar evolution on the cluster population. In addition, the gravitational forces due to the Milky Way potential are accounted for in a self-consistent manner. Our aim is to understand how the astrometric and radial velocity data from the Gaia mission can be used to pre-select solar sibling candidates. We vary the initial conditions of the Sun's birth cluster, as well as the parameters of the Galactic potential. In particular, we use different configurations and strengths of the bar and spiral arms. We show that the disruption time-scales of the cluster are insensitive to the details of the non-axisymmetric components of the Milky Way model and we make predictions, averaged over the different simulated possibilities, about the number of solar siblings that should appear in surveys such as Gaia or GALAH. We find a large variety of present-day phase-space distributions of solar siblings, which depend on the cluster initial conditions and the Milky Way model parameters. We show that nevertheless robust predictions can be made about the location of the solar siblings in the space of parallaxes (ϖ), proper motions (μ) and radial velocities (Vr). By calculating the ratio of the number of simulated solar siblings to that of the number of stars in a model Galactic disc, we find that this ratio is above 0.5 in the region given by: ϖ ≥ 5 mas, 4 ≤ μ ≤ 6 mas yr-1, and -2 ≤ Vr ≤ 0 km s-1. Selecting stars from this region should increase the probability of success in identifying solar siblings through follow-up observations. However the proposed pre-selection criterion is sensitive to our assumptions, in particular about the Galactic potential. Using a more

  5. Can the Solar Wind be Driven by Magnetic Reconnection in the Sun's Magnetic Carpet?

    CERN Document Server

    Cranmer, Steven R

    2010-01-01

    The physical processes that heat the solar corona and accelerate the solar wind remain unknown after many years of study. Some have suggested that the wind is driven by waves and turbulence in open magnetic flux tubes, and others have suggested that plasma is injected into the open tubes by magnetic reconnection with closed loops. In order to test the latter idea, we developed Monte Carlo simulations of the photospheric "magnetic carpet" and extrapolated the time-varying coronal field. These models were constructed for a range of different magnetic flux imbalance ratios. Completely balanced models represent quiet regions on the Sun and source regions of slow solar wind streams. Highly imbalanced models represent coronal holes and source regions of fast wind streams. The models agree with observed emergence rates, surface flux densities, and number distributions of magnetic elements. Despite having no imposed supergranular motions, a realistic network of magnetic "funnels" appeared spontaneously. We computed t...

  6. The evolution of the Sun's birth cluster and the search for the solar siblings with Gaia

    CERN Document Server

    Martínez-Barbosa, C A; Boekholt, T; Zwart, S Portegies; Antiche, E; Antoja, T

    2016-01-01

    We use self-consistent numerical simulations of the evolution and disruption of the Sun's birth cluster in the Milky Way potential to investigate the present-day phase space distribution of the Sun's siblings. The simulations include the gravitational N-body forces within the cluster and the effects of stellar evolution on the cluster population. In addition the gravitational forces due to the Milky Way potential are accounted for in a self-consistent manner. Our aim is to understand how the astrometric and radial velocity data from the Gaia mission can be used to pre-select solar sibling candidates. We vary the initial conditions of the Sun's birth cluster, as well as the parameters of the Galactic potential. We show that the disruption time-scales of the cluster are insensitive to the details of the non-axisymmetric components of the Milky Way model and we make predictions, averaged over the different simulated possibilities, about the number of solar siblings that should appear in surveys such as Gaia or G...

  7. Solar Energy Research Center Instrumentation Facility

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Thomas, J.; Papanikolas, John, P.

    2011-11-11

    SOLAR ENERGY RESEARCH CENTER INSTRUMENTATION FACILITY The mission of the Solar Energy Research Center (UNC SERC) at the University of North Carolina at Chapel Hill (UNC-CH) is to establish a world leading effort in solar fuels research and to develop the materials and methods needed to fabricate the next generation of solar energy devices. We are addressing the fundamental issues that will drive new strategies for solar energy conversion and the engineering challenges that must be met in order to convert discoveries made in the laboratory into commercially available devices. The development of a photoelectrosynthesis cell (PEC) for solar fuels production faces daunting requirements: (1) Absorb a large fraction of sunlight; (2) Carry out artificial photosynthesis which involves multiple complex reaction steps; (3) Avoid competitive and deleterious side and reverse reactions; (4) Perform 13 million catalytic cycles per year with minimal degradation; (5) Use non-toxic materials; (6) Cost-effectiveness. PEC efficiency is directly determined by the kinetics of each reaction step. The UNC SERC is addressing this challenge by taking a broad interdisciplinary approach in a highly collaborative setting, drawing on expertise across a broad range of disciplines in chemistry, physics and materials science. By taking a systematic approach toward a fundamental understanding of the mechanism of each step, we will be able to gain unique insight and optimize PEC design. Access to cutting-edge spectroscopic tools is critical to this research effort. We have built professionally-staffed facilities equipped with the state-of the-art instrumentation funded by this award. The combination of staff, facilities, and instrumentation specifically tailored for solar fuels research establishes the UNC Solar Energy Research Center Instrumentation Facility as a unique, world-class capability. This congressionally directed project funded the development of two user facilities: TASK 1: SOLAR

  8. Sensitivity of Utility-Scale Solar Deployment Projections in the SunShot Vision Study to Market and Performance Assumptions

    Energy Technology Data Exchange (ETDEWEB)

    Eurek, K.; Denholm, P.; Margolis, R.; Mowers, M.

    2013-04-01

    The SunShot Vision Study explored the potential growth of solar markets if solar prices decreased by about 75% from 2010 to 2020. The ReEDS model was used to simulate utility PV and CSP deployment for this present study, based on several market and performance assumptions - electricity demand, natural gas prices, coal retirements, cost and performance of non-solar renewable technologies, PV resource variability, distributed PV deployment, and solar market supply growth - in addition to the SunShot solar price projections. This study finds that utility-scale solar deployment is highly sensitive to solar prices. Other factors can have significant impacts, particularly electricity demand and natural gas prices.

  9. Maximizing Output Power of a Solar Panel via Combination of Sun Tracking and Maximum Power Point Tracking by Fuzzy Controllers

    Directory of Open Access Journals (Sweden)

    Mohsen Taherbaneh

    2010-01-01

    Full Text Available In applications with low-energy conversion efficiency, maximizing the output power improves the efficiency. The maximum output power of a solar panel depends on the environmental conditions and load profile. In this paper, a method based on simultaneous use of two fuzzy controllers is developed in order to maximize the generated output power of a solar panel in a photovoltaic system: fuzzy-based sun tracking and maximum power point tracking. The sun tracking is performed by changing the solar panel orientation in horizontal and vertical directions by two DC motors properly designed. A DC-DC converter is employed to track the solar panel maximum power point. In addition, the proposed system has the capability of the extraction of solar panel I-V curves. Experimental results present that the proposed fuzzy techniques result in increasing of power delivery from the solar panel, causing a reduction in size, weight, and cost of solar panels in photovoltaic systems.

  10. Studying the Sun's Nuclear Furnace with a Neutrino Detector Spacecraft in Close Solar Orbit

    Science.gov (United States)

    Solomey, Nickolas

    2016-05-01

    A neutrino based detector in close solar orbit would have a neutrino flux 10,000x or more larger flux than on Earth and a smaller detector able to handle high rates with exception energy resolution could be used. We have studied the idea of operating such an experiment in close solar orbits that takes it off the ecliptic plane and in a solar orbit where the distance from the Sun will change distance. This neutrino detector on a space craft could do Solar Astrophysics studying the Solar nuclear furnace, basic nuclear physics and elementary particle physics; some of these ideas are new unique science that can only be preformed from a spacecraft. The harsh environment provides many challenges but if such a detector could be made to work it can be the next major step in this science study. How a small segmented detector can operate and preform in this environment to detect solar neutrinos will be elaborated upon using a combination of signal strength, fast signal timing, shielding and segmentation.

  11. Commentary on the Liquid Metallic Hydrogen Model of the Sun: Insight Relative to Coronal Holes, Sunspots, and Solar Activity

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-04-01

    Full Text Available While mankind will always remain unable to sample the interior of the Sun, the presence of sunspots and coronal holes can provide clues as to its subsurface structure. Insight relative to the solar body can also be gained by recognizing that the Sun must exist in the condensed state and support a discrete lattice structure, as required for the production of its continuous spectrum. In this regard, the layered liquid metallic hydrogen lattice advanced as a condensed model of the Sun (Robitaille P.M. Liquid Metallic Hydrogen: A Building Block for the Liquid Sun. Progr. Phys ., 2011, v. 3, 60–74; Robitaille P.M. Liquid Metallic Hydrogen II: A Critical Assessment of Current and Primordial Helium Levels in Sun. Progr. Phys ., 2013, v. 2, 35–47; Robitaille J.C. and Robitaille P.M. Liquid Metallic Hydrogen III. Intercalation and Lattice Exclusion Versus Gravitational Settling and Their Consequences Relative to Internal Structure, Surface Activity, and Solar Winds in the Sun. Progr. Phys ., 2013, v. 2, in press provides the ability to add structure to the solar interior. This constitutes a significant advantage over the gaseous solar models. In fact, a layered liquid metallic hydrogen lattice and the associated intercalation of non-hydrogen elements can help to account for the position of sunspots and coronal holes. At the same time, this model provides a greater understanding of the mechanisms which drive solar winds and activity.

  12. STUDY OF CALIBRATION OF SOLAR RADIO SPECTROMETERS AND THE QUIET-SUN RADIO EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Chengming; Yan, Yihua; Tan, Baolin; Fu, Qijun; Liu, Yuying [Key Laboratory of Solar Activity, National Astronomical Observatories of Chinese Academy of Sciences, Datun Road A20, Chaoyang District, Beijing 100012 (China); Xu, Guirong [Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research, Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205 (China)

    2015-07-20

    This work presents a systematic investigation of the influence of weather conditions on the calibration errors by using Gaussian fitness, least chi-square linear fitness, and wavelet transform to analyze the calibration coefficients from observations of the Chinese Solar Broadband Radio Spectrometers (at frequency bands of 1.0–2.0 GHz, 2.6–3.8 GHz, and 5.2–7.6 GHz) during 1997–2007. We found that calibration coefficients are influenced by the local air temperature. Considering the temperature correction, the calibration error will reduce by about 10%–20% at 2800 MHz. Based on the above investigation and the calibration corrections, we further study the radio emission of the quiet Sun by using an appropriate hybrid model of the quiet-Sun atmosphere. The results indicate that the numerical flux of the hybrid model is much closer to the observation flux than that of other ones.

  13. Study of Calibration of Solar Radio Spectrometers and the quiet-Sun Radio Emission

    CERN Document Server

    Tan, Chengming; Tan, Baolin; Fu, Qijun; Liu, Yuying; Xu, Guirong

    2015-01-01

    This work presents a systematic investigation of the influence of weather conditions on the calibration errors by using Gaussian fitness, least chi-square linear fitness and wavelet transform to analyze the calibration coefficients from observations of the Chinese Solar Broadband Radio Spectrometers (at frequency bands of 1.0-2.0 GHz, 2.6-3.8 GHz, and 5.2-7.6 GHz) during 1997-2007. We found that calibration coefficients are influenced by the local air temperature. Considering the temperature correction, the calibration error will reduce by about $10\\%-20\\%$ at 2800 MHz. Based on the above investigation and the calibration corrections, we further study the radio emission of the quiet-Sun by using an appropriate hybrid model of the quiet-Sun atmosphere. The results indicate that the numerical flux of the hybrid model is much closer to the observation flux than that of other ones.

  14. Conversion of commercial si solar cells to keep their efficient performance at 15 suns

    Energy Technology Data Exchange (ETDEWEB)

    Coello, J. [Instituto Tecnologico y de Energias Renovables, Poligono Industrial de Granadilla, Tenerife (Spain); Castro, M.; Anton, I.; Sala, G. [Ciudad Univ., Madrid (Spain). Inst. de Energia Solar; Vazquez, M.A. [Isofoton, S.A., Poligono Industrial Santa Cruz, Malaga (Spain)

    2004-07-01

    The screen-printing method is an economical metallization technique used by most manufacturers of conventional silicon solar cells. This method limits the cells' use under concentrated light owing to high series resistance losses caused, among other reasons, by low metal density in the fingers. This paper describes increasing the finger metal density by electrolytic deposition. The electrolytic deposition of silver is an economical, controllable and readily commercializable deposition method to reduce the front and back metallization series resistance contributions. With an optimized grid design, compatible with 1 sun silicon cell technology, and later electrolytic silver deposition we have obtained cells that maintain their efficiency up to 15 suns. In addition, an analysis of the performance of these cells under uniform and non-uniform illumination were carried out on n{sup +}p and n{sup +}pn{sup +} structures. (author)

  15. Chromospheric activity and evolutionary age of the Sun and four solar twins

    CERN Document Server

    Mittag, M; Hempelmann, A; González-Pérez, J N; Schmitt, J H M M

    2016-01-01

    The activity levels of the solar-twin candidates HD 101364 and HD 197027 are measured and compared with the Sun, the known solar twin 18 Sco, and the solar-like star 51 Peg. Furthermore, the absolute ages of these five objects are estimated from their positions in the HR diagram and the evolutionary (relative) age compared with their activity levels. To represent the activity level of these stars, the Mount Wilson S-indices were used. To obtain consistent ages and evolutionary advance on the main sequence, we used evolutionary tracks calculated with the Cambridge Stellar Evolution Code. From our spectroscopic observations of HD 101364 and HD 197027 and based on the established calibration procedures, the respective Mount Wilson S-indices are determined. We find that the chromospheric activity of both stars is comparable with the present activity level of the Sun and that of 18 Sco, at least for the period in consideration. Furthermore, the absolute age of HD 101364, HD 197027, 51 Peg, and 18 Sco are found to ...

  16. Sun-Like Magnetic Cycles in the Rapidly-Rotating Young Solar Analog HD 30495

    CERN Document Server

    Egeland, Ricky; Hall, Jeffrey C; Henry, Gregory W

    2015-01-01

    A growing body of evidence suggests that multiple dynamo mechanisms can drive magnetic variability on different timescales, not only in the Sun but also in other stars. Many solar activity proxies exhibit a quasi-biennial ($\\sim$2 year) variation, which is superimposed upon the dominant 11 year cycle. A well-characterized stellar sample suggests at least two different relationships between rotation period and cycle period, with some stars exhibiting long and short cycles simultaneously. Within this sample, the solar cycle periods are typical of a more rapidly rotating star, implying that the Sun might be in a transitional state or that it has an unusual evolutionary history. In this work, we present new and archival observations of dual magnetic cycles in the young solar analog HD 30495, an $\\sim$1 Gyr-old G1.5V star with a rotation period near 11 days. This star falls squarely on the relationships established by the broader stellar sample, with short-period variations at $\\sim$1.7 years and a long cycle of $...

  17. Particle Acceleration at the Sun and in the Inner Heliosphere: Implications for Solar Orbiter

    Science.gov (United States)

    Wimmer-Schweingruber, Robert; Mason, Glenn; Boettcher, Stephan; Blanco, Juan Jose; Martin, Cesar; Kulkarni, Shrinivasrao; Sanchez, Sebastian; Rodriguez-Pacheco, Javier; Prieto, Manuel; Panitzsch, Lauri; Gomez-Herrero, Raul

    The Sun occasionally accelerates particles to high energies and sometimes fills the heliosphere with them. It is thus the best accessible example for this astrophysically important process. Several processes appear to be involved, ranging from magnetic reconnection to shock waves in the corona and inner heliosphere. Particles are somehow distributed across magnetic field lines and are measured at locations which do not appear to be magnetically connected with the source of the particles. Thus the Sun poses a puzzle which is best solved by coordinated observations from many carefully chosen vantage points and using multiple measurement techniques. We will discuss the scientific background of energetic particles in the heliosphere and how to address their origin, injection, acceleration, and transport in the inner heliosphere using upcoming missions such as Solar Orbiter and Solar Probe Plus with a special focus on Solar Orbiter's Energetic Particle Detector (EPD). It consists of a suite of sensors which will measure protons (electrons) from 3 (2) keV up to 100 (20) MeV and ions from few tens of keV/nuc to 200 MeV/nuc.

  18. A generic sun-tracking algorithm for on-axis solar collector in mobile platforms

    Science.gov (United States)

    Lai, An-Chow; Chong, Kok-Keong; Lim, Boon-Han; Ho, Ming-Cheng; Yap, See-Hao; Heng, Chun-Kit; Lee, Jer-Vui; King, Yeong-Jin

    2015-04-01

    This paper proposes a novel dynamic sun-tracking algorithm which allows accurate tracking of the sun for both non-concentrated and concentrated photovoltaic systems located on mobile platforms to maximize solar energy extraction. The proposed algorithm takes not only the date, time, and geographical information, but also the dynamic changes of coordinates of the mobile platforms into account to calculate the sun position angle relative to ideal azimuth-elevation axes in real time using general sun-tracking formulas derived by Chong and Wong. The algorithm acquires data from open-loop sensors, i.e. global position system (GPS) and digital compass, which are readily available in many off-the-shelf portable gadgets, such as smart phone, to instantly capture the dynamic changes of coordinates of mobile platforms. Our experiments found that a highly accurate GPS is not necessary as the coordinate changes of practical mobile platforms are not fast enough to produce significant differences in the calculation of the incident angle. On the contrary, it is critical to accurately identify the quadrant and angle where the mobile platforms are moving toward in real time, which can be resolved by using digital compass. In our implementation, a noise filtering mechanism is found necessary to remove unexpected spikes in the readings of the digital compass to ensure stability in motor actuations and effectiveness in continuous tracking. Filtering mechanisms being studied include simple moving average and linear regression; the results showed that a compound function of simple moving average and linear regression produces a better outcome. Meanwhile, we found that a sampling interval is useful to avoid excessive motor actuations and power consumption while not sacrificing the accuracy of sun-tracking.

  19. Sun-to-Earth Analysis of a Major Geoeffective Solar Eruption within the Framework of the

    Science.gov (United States)

    Patsourakos, S.; Vlahos, L.; Georgoulis, M.; Tziotziou, K.; Nindos, A.; Podladchikova, O.; Vourlidas, A.; Anastasiadis, A.; Sandberg, I.; Tsinganos, K.; Daglis, I.; Hillaris, A.; Preka-Papadema, P.; Sarris, M.; Sarris, T.

    2013-09-01

    Transient expulsions of gigantic clouds of solar coronal plasma into the interplanetary space in the form of Coronal Mass Ejections (CMEs) and sudden, intense flashes of electromagnetic radiation, solar flares, are well-established drivers of the variable Space Weather. Given the innate, intricate links and connections between the solar drivers and their geomagnetic effects, synergistic efforts assembling all pieces of the puzzle along the Sun-Earth line are required to advance our understanding of the physics of Space Weather. This is precisely the focal point of the Hellenic National Space Weather Research Network (HNSWRN) under the THALIS Programme. Within the HNSWRN framework, we present here the first results from a coordinated multi-instrument case study of a major solar eruption (X5.4 and X1.3 flares associated with two ultra-fast (>2000 km/s) CMEs) which were launched early on 7 March 2012 and triggered an intense geomagnetic storm (min Dst =-147 nT) approximately two days afterwards. Several elements of the associated phenomena, such as the flare and CME, EUV wave, WL shock, proton and electron event, interplanetary type II radio burst, ICME and magnetic cloud and their spatiotemporal relationships and connections are studied all way from Sun to Earth. To this end, we make use of satellite data from a flotilla of solar, heliospheric and magnetospheric missions and monitors (e.g., SDO, STEREO, WIND, ACE, Herschel, Planck and INTEGRAL). We also present our first steps toward formulating a cohesive physical scenario to explain the string of the observables and to assess the various physical mechanisms than enabled and gave rise to the significant geoeffectiveness of the eruption.

  20. A Thermodynamic History of the Solar Constitution — I: The Journey to a Gaseous Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available History has the power to expose the origin and evolution of scientific ideas. How did humanity come to visualize the Sun as a gaseous plasma? Why is its interior thought to contain blackbody radiation? Who were the first people to postulate that the density of the solar body varied greatly with depth? When did mankind first conceive that the solar surface was merely an illusion? What were the foundations of such thoughts? In this regard, a detailed review of the Sun’s thermodynamic history provides both a necessary exposition of the circumstance which accompanied the acceptance of the gaseous mod- els and a sound basis for discussing modern solar theories. It also becomes an invitation to reconsider the phase of the photosphere. As such, in this work, the contributions of Pierre Simon Laplace, Alexander Wilson, William Herschel, Hermann von Helmholtz, Herbert Spencer, Richard Christopher Carrington, John Frederick William Herschel, Father Pietro Angelo Secchi, Herv ́ e August Etienne Albans Faye, Edward Frankland, Joseph Norman Lockyer, Warren de la Rue, Balfour Stewart, Benjamin Loewy, and Gustav Robert Kirchhoff, relative to the evolution of modern stellar models, will be discussed. Six great pillars created a gaseous Sun: 1 Laplace’s Nebular Hypothesis, 2 Helmholtz’ contraction theory of energy production, 3 Andrew’s elucidation of crit- ical temperatures, 4 Kirchhoff’s formulation of his law of thermal emission, 5 Pl ̈ ucker and Hittorf’s discovery of pressure broadening in gases, and 6 the evolution of the stel- lar equations of state. As these are reviewed, this work will venture to highlight not only the genesis of these revolutionary ideas, but also the forces which drove great men to advance a gaseous Sun.

  1. Spectral analysis of two solar twins and the colors of the Sun

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    High resolution (R~40,000) and high signal-to-noise ratio (>150) spectra of two solar twins, HD146233 and HD195034, are obtained with the Coude Echelle Spectrograph at the 2.16 m telescope of the National Astronomical Observatories of Chinese Academy of Sciences (Xinglong, China). Based on the detailed spectrum match, comparisons of chemical composition and chromospheric activity, HD146233 and HD195034 are confirmed that they are similar to the Sun except for lithium abundance, which is higher than the solar value. Moreover, among nine solar twin candidates (including HD146233 and HD195034) found in the previous works, we have picked out six good solar twin candidates based on newly-derived homogenous parameters, and collected their colors in the Johnson/Cousins, Tycho, 2MASS and Strmgren system from the literature. The average color are (B-V)⊙=0.644 mag, (V-Ic)⊙=0.707 mag, (BT-VT)⊙=0.725 mag, (J-H)⊙=0.288 mag, (H-K)⊙=0.066 mag, (v-y)⊙=1.028 mag, (v-b)⊙=0.619 mag, (u-v)⊙=0.954 mag and (b-y)⊙=0.409 mag, which represent the solar colors with higher precision than previous works.

  2. The Solar Twin Planet Search: IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars

    CERN Document Server

    Santos, Leonardo A dos; Nascimento, José-Dias do; Bedell, Megan; Ramírez, Iván; Bean, Jacob L; Asplund, Martin; Spina, Lorenzo; Dreizler, Stefan; Alves-Brito, Alan; Casagrande, Luca

    2016-01-01

    It is still unclear how common the Sun is when compared to other similar stars in regards to some of its physical properties, such as rotation. Considering that gyrochronology relations are widely used today to estimate ages of stars in the main sequence, and that the Sun is used to calibrate it, it is crucial to assess if these procedures are acceptable. We analyze the rotational velocities -- limited by the unknown rotation axis inclination angle -- of an unprecedented large sample of solar twins in order to study the rotational evolution of Sun-like stars, and assess if the Sun is a typical rotator. We use high-resolution ($R = 115000$) spectra obtained with the HARPS spectrograph and ESO's 3.6 m telescope at La Silla Observatory. The projected rotational velocities for 82 solar twins are estimated by line profile fitting with synthetic spectra. Macroturbulence velocities are inferred from a prescription that accurately reflects their dependence with effective temperature and luminosity of the stars. Our s...

  3. Polarized Light from the Sun: Unification of the Corona and Analysis of the Second Solar Spectrum — Further Implications of a Liquid Metallic Hydrogen Solar Model

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2015-07-01

    Full Text Available In order to account for the slight polarization of the continuum towards the limb, propo- nents of the Standard Solar Model (SSM must have recourse to electron or hydrogen- based scattering of light, as no other mechanism is possible in a gaseous Sun. Con- versely, acceptance that the solar body is comprised of condensed matter opens up new avenues in the analysis of this problem, even if the photospheric surface itself is viewed as incapable of emitting polarized light. Thus, the increased disk polarization, from the center to the limb, can be explained by invoking the scattering of light by the at- mosphere above the photosphere. The former is reminiscent of mechanisms which are known to account for the polarization of sunlight in the atmosphere of the Earth. Within the context of the Liquid Metallic Hydrogen Solar Model (LMHSM, molecules and small particles, not electrons or hydrogen atoms as required by the SSM, would primarily act as scattering agents in regions also partially comprised of condensed hy- drogen structures (CHS. In addition, the well-known polarization which characterizes the K-corona would become a sign of emission polarization from an anisotropic source, without the need for scattering. In the LMHSM, the K, F, and T- coronas can be viewed as emissive and reflective manifestations of a single corona l entity adopting a radially anisotropic structure, while slowly cooling with altitude above the photosphere. The presence of “dust particles”, advanced by proponents of the SSM, would no longer be required to explain the F and T-corona, as a single cooling structure would account for the properties of the K, F, and T coronas. At the same time, the polarized “Second Solar Spectrum”, characterized by the dominance of certain elemental or ionic spectral lines and an abundance of molecular lines, could be explained in the LMHSM, by first invoking interface polarization and coordination of these species with condensed matter

  4. Can the Solar Wind be Driven by Magnetic Reconnection in the Sun's Magnetic Carpet?

    Science.gov (United States)

    Cranmer, Steven R.; van Ballegooijen, Adriaan A.

    2010-09-01

    The physical processes that heat the solar corona and accelerate the solar wind remain unknown after many years of study. Some have suggested that the wind is driven by waves and turbulence in open magnetic flux tubes, and others have suggested that plasma is injected into the open tubes by magnetic reconnection with closed loops. In order to test the latter idea, we developed Monte Carlo simulations of the photospheric "magnetic carpet" and extrapolated the time-varying coronal field. These models were constructed for a range of different magnetic flux imbalance ratios. Completely balanced models represent quiet regions on the Sun and source regions of slow solar wind streams. Highly imbalanced models represent coronal holes and source regions of fast wind streams. The models agree with observed emergence rates, surface flux densities, and number distributions of magnetic elements. Despite having no imposed supergranular motions in the models, a realistic network of magnetic "funnels" appeared spontaneously. We computed the rate at which closed field lines open up (i.e., recycling times for open flux), and we estimated the energy flux released in reconnection events involving the opening up of closed flux tubes. For quiet regions and mixed-polarity coronal holes, these energy fluxes were found to be much lower than that which is required to accelerate the solar wind. For the most imbalanced coronal holes, the energy fluxes may be large enough to power the solar wind, but the recycling times are far longer than the time it takes the solar wind to accelerate into the low corona. Thus, it is unlikely that either the slow or fast solar wind is driven by reconnection and loop-opening processes in the magnetic carpet.

  5. QE and Suns-Voc study on the epitaxial CSiTF solar cells

    Institute of Scientific and Technical Information of China (English)

    AI Bin; SHEN Hui; BAN Qun; LIANG Zongcun; CHEN Rulong; SHI Zhengrong; LIAO Xianbo

    2005-01-01

    In order to clarify the major factors having confined the efficiencies of as-prepared crystalline silicon thin film (CSiTF) solar cells on the SSP (silicon sheets from powder) ribbons, QE (quantum efficiency) and Suns-Voc study were performed on the epitaxial CSiTF solar cells fabricated on the SSP ribbons, the SSP ribbons after surface being zone melting recrystallized (ZMR) and single crystalline silicon (sc-Si) substrates.The results show that the epi-layers deposited on the SSP ribbons have rough surfaces,which not only increases the diffusion reflectance on the surfaces but also makes the anti-reflection coatings become structure-loosened, both of which would deteriorate the light trapping effect; in addition, the epi-layers deposited on the SSP ribbons possess poor crystallographic quality, so the heavy grain boundary (GB) recombination limits the diffusion length of the minority carriers in the epi-layers, which makes the as-prepared CSiTF solar cells suffer the worse spectra response at long-wavelength range. Nearly all the dark characteristic parameters of the CSiTF solar cells are far away from the ideal values. The performances of the CSiTF solar cells are especially affected by too high I02 (the dark saturation current of space charge region) values and too low Rsh (parallel resistance) values. The higher I02 values are mainly caused by the heavy GB recombination resulting from the poor crystallographic qualities of the silicon active layers in the space charge regions, while the lower Rsh values are attributed to the electrical leakage at the un-passivated PN junction or solar cell edges after the solar cells are cut by the laser scriber.

  6. The Structure and Properties of Solar Active Regions and Quiet Sun Areas Observed With SERTS and YOHKOH

    Science.gov (United States)

    Brosius, J. W.; Davila, J. M.; Thomas, R. J.; Hara, H.

    1996-05-01

    We observed solar active regions, quiet sun areas, and a coronal hole simultaneously with Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph (SERTS), and with the Yohkoh Soft X-Ray Telescope (SXT) on 1993 August 17. SERTS provided spatially resolved active region and quiet sun spectra in the 280 to 420 Angstroms wavelength range, and images in the lines of He II 304 Angstroms, Mg IX 368 Angstroms, Fe XV 284 Angstroms, and Fe XVI 335 Angstroms and 360 Angstroms. The SERTS waveband is accessible to CDS, SUMER, and EIT on SOHO. SXT provided images through multiple broadband filters. The SERTS images in Fe XV (T=2 MK) and XVI (T=2.5 MK) exhibit remarkable morphological similarity to the SXT images. Whereas the Fe XV and XVI images outline the loop structures seen with SXT, the cooler He II (T=0.1 MK) and Mg IX (T=1 MK) images seem to outline loop footpoints. From the spatially resolved spectra, we obtained emission line profiles for lines of Fe X (1 MK) through Fe XVI, and Mg IX and Ni XVIII (3.2 MK) for each spatial position. Based upon the spatial variations of the line intensities, the active region systematically narrows as it is viewed with successively hotter lines. The active region appears narrowest in the X-ray emission, which is consistent with our understanding that Yohkoh is most sensitive to the hottest plasma in its line of sight. EUV emission from Fe XVII (T=5 MK) is weak but detectable in the active region core. The most intense, central core straddles the magnetic neutral line. Temperature maps obtained with SERTS image ratios and with SXT filter ratios are compared. Line intensity ratios indicate that the active region temperature is greatest in the central core, but that the density varies very little across the region. Significant Doppler shifts are not detected in the EUV lines.

  7. On the Path to SunShot - Advancing Concentrating Solar Power Technology, Performance, and Dispatchability

    Energy Technology Data Exchange (ETDEWEB)

    Mehos, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ho, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-05-01

    Energy storage will help enable CSP compete by adding flexibility value to a high-variable-generation (solar plus wind) power system (see Mehos et al. 2016). Compared with PV, CSP systems are more complex to develop, design, construct, and operate, and they require a much larger minimum effective scale—typically at least 50 MW, compared with PV systems that can be as small as a few kilowatts. In recent years, PV’s greater modularity and lower LCOE have made it more attractive to many solar project developers, and some large projects that were originally planned for CSP have switched to PV. However, the ability of CSP to use thermal energy storage—and thus provide continuous power for long periods when the sun is not shining—could give CSP a vital role in evolving electricity systems. Because CSP with storage can store energy when net demand is low and release that energy when demand is high, it increases the electricity system’s ability to balance supply and demand over multiple time scales. Such flexibility becomes increasingly important as more variable-generation renewable energy is added to the system. For example, one analysis suggests that, under a 40% renewable portfolio standard in California, CSP with storage could provide more than twice as much value to the electricity system as variable-generation PV. For this reason, enhanced thermal energy storage is a critical component of the SunShot Initiative’s 2020 CSP technology-improvement roadmap.

  8. Three-degree-of-freedom parallel manipulator to track the sun for concentrated solar power systems

    Science.gov (United States)

    Ashith Shyam, R. B.; Ghosal, A.

    2015-07-01

    In concentrated solar power(CSP) generating stations, incident solar energy is reflected from a large number of mirrors or heliostats to a faraway receiver. In typical CSP installations, the mirror needs to be moved about two axes independently using two actuators in series with the mirror effectively mounted at a single point. A three degree-of-freedom parallel manipulator, namely the 3-RPS parallel manipulator, is proposed to track the sun. The proposed 3-RPS parallel manipulator supports the load of the mirror, structure and wind loading at three points resulting in less deflection, and thus a much larger mirror can be moved with the required tracking accuracy and without increasing the weight of the support structure. The kinematics equations to determine motion of the actuated prismatic joints in the 3-RPS parallel manipulator such that the sun's rays are reflected on to a stationary receiver are developed. Using finite element analysis, it is shown that for same sized mirror, wind loading and maximum deflection requirement, the weight of the support structure is between 15% and 60% less with the 3-RPS parallel manipulator when compared to azimuth-elevation or the target-aligned configurations.

  9. Dynamo model for grand maxima of solar activity: can superflares occur on the Sun?

    CERN Document Server

    Kitchatinov, L L

    2016-01-01

    Recent data on superflares on sun-like stars and radiocarbon data on solar activity in the past are both indicative of transient epochs of unusually high magnetic activity. We propose an explanation for the grand activity maxima in the framework of a solar dynamo model with fluctuating parameters. Solar-type dynamos are oscillatory because of the combination of the solar-type differential rotation with positive (in the northern hemisphere) alpha-effect. An artificial reversal of the sign in the alpha-effect changes the dynamo to a steady regime with hundreds of times larger magnetic energy compared to the amplitude of the cyclic dynamo. Sufficiently large and durable fluctuations reversing the sign of the alpha-effect during the growth phase of a magnetic cycle can, therefore, cause a transient change to a steady dynamo with considerably increased magnetic energy. This qualitative scenario for grand activity maxima is supported by computations of the dynamo model with a fluctuating alpha-effect. The computed ...

  10. Platinum Alloy Tailored All-Weather Solar Cells for Energy Harvesting from Sun and Rain.

    Science.gov (United States)

    Tang, Qunwei; Duan, Yanyan; He, Benlin; Chen, Haiyan

    2016-11-07

    Solar cells that can harvest energy in all weathers are promising in solving the energy crisis and environmental problems. The power outputs are nearly zero under dark conditions for state-of-the-art solar cells. To address this issue, we present herein a class of platinum alloy (PtMx , M=Ni, Fe, Co, Cu, Mo) tailored all-weather solar cells that can harvest energy from rain and realize photoelectric conversion under sun illumination. By tuning the stoichiometric Pt/M ratio and M species, the optimized solar cell yields a photoelectric conversion efficiency of 10.38 % under simulated sunlight irradiation (AM 1.5, 100 mW cm(-2) ) as well as current of 3.90 μA and voltage of 115.52 μV under simulated raindrops. Moreover, the electric signals are highly dependent on the dripping velocity and the concentration of simulated raindrops along with concentrations of cation and anion.

  11. Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun's Activity

    CERN Document Server

    Karak, Bidya Binay

    2012-01-01

    Prediction of the Sun's magnetic activity is important because of its effect on space environmental conditions and climate. However, recent efforts to predict the amplitude of the solar cycle have resulted in diverging forecasts with no consensus. It is understood that the dynamical memory of the solar dynamo mechanism governs predictability and this memory is different for advection- and diffusion-dominated solar convection zones. By utilizing stochastically forced, kinematic dynamo simulations, we demonstrate that the inclusion of downward turbulent pumping of magnetic flux reduces the memory of both advection- and diffusion-dominated solar dynamos to only one cycle; stronger pumping degrades this memory further. We conclude that reliable predictions for the maximum of solar activity can be made only at the preceding minimum and for more accurate predictions, sequential data assimilation would be necessary in forecasting models to account for the Sun's short memory.

  12. The chemical composition of the sun from helioseismic and solar neutrino data

    Energy Technology Data Exchange (ETDEWEB)

    Villante, Francesco L. [Dipartimento di Scienze Fisiche e Chimiche, Università dell' Aquila, I-67100 L' Aquila (Italy); Serenelli, Aldo M. [Instituto de Ciencias del Espacio (CSIC-IEEC), Facultad de Ciencias, E-08193 Bellaterra (Spain); Delahaye, Franck [LERMA, Observatoire de Paris, ENS, UPMC, UCP, CNRS, F-92190 Meudon (France); Pinsonneault, Marc H. [Astronomy Department, Ohio State University, Columbus, OH 43210 (United States)

    2014-05-20

    We perform a quantitative analysis of the solar composition problem by using a statistical approach that allows us to combine the information provided by helioseismic and solar neutrino data in an effective way. We include in our analysis the helioseismic determinations of the surface helium abundance and of the depth of the convective envelope, the measurements of the {sup 7}Be and {sup 8}B neutrino fluxes, and the sound speed profile inferred from helioseismic frequencies. We provide all the ingredients to describe how these quantities depend on the solar surface composition, different from the initial and internal composition due to the effects of diffusion and nuclear reactions, and to evaluate the (correlated) uncertainties in solar model predictions. We include error sources that are not traditionally considered such as those from inversion of helioseismic data. We, then, apply the proposed approach to infer the chemical composition of the Sun. Our result is that the opacity profile of the Sun is well constrained by the solar observational properties. In the context of a two-parameter analysis in which elements are grouped as volatiles (i.e., C, N, O, and Ne) and refractories (i.e., Mg, Si, S, and Fe), the optimal surface composition is found by increasing the abundance of volatiles by (45 ± 4)% and that of refractories by (19 ± 3)% with respect to the values provided by Asplund et al. (2009, ARA and A, 47, 481). This corresponds to the abundances ε{sub O} = 8.85 ± 0.01 and ε{sub Fe} = 7.52 ± 0.01, which are consistent at the ∼1σ level with those provided by Grevesse and Sauval (1998, SSRv, 85, 161). As an additional result of our analysis, we show that the best fit to the observational data is obtained with values of input parameters of the standard solar models (radiative opacities, gravitational settling rate, and the astrophysical factors S {sub 34} and S {sub 17}) that differ at the ∼1σ level from those presently adopted.

  13. Experimental investigation on the comparison of fenugreek drying in an indirect solar dryer and under open sun

    Science.gov (United States)

    Shrivastava, Vipin; Kumar, Anil

    2016-09-01

    The convective heat transfer coefficient is an essential parameter for designing of any solar drying system. In this paper heat transfer modeling in term of convective heat transfer coefficient is performed and compared with open sun drying. The data obtained from experimentation under open sun and indirect solar drying conditions have been used to find values of the experimental constant `C' and exponent `n' by regression analysis and, consequently, convective heat transfer coefficient. From this study it is concluded that the convective heat transfer coefficient is decreasing with drying time it is due to decrease in moisture content. Results also showed that convective heat transfer coefficients are more in indirect solar dryer system than under open sun drying.

  14. Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

    OpenAIRE

    McKibben, R. B.; Connell, J. J.; Lopate, C.; Zhang, M.; Anglin, J.D.; Balogh, A.; Dalla, S.; Sanderson, T. R.; Marsden, R. G.; Hofer, M. Y.; Kunow, H.; Posner, A.; Heber, B.

    2003-01-01

    In 2000–2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum.  Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but ...

  15. PROBING THE SOLAR WIND ACCELERATION REGION WITH THE SUN-GRAZING COMET C/2002 S2

    Energy Technology Data Exchange (ETDEWEB)

    Giordano, S. [INAF-Osservatorio Astrofisico di Torino, via Osservatorio 20, I-10025 Pino Torinese (Italy); Raymond, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lamy, P. [Laboratoire d' Astrophysique de Marseille, 38 rue Frédéric Joliot-Curie, F-13388 Marseille cedex 13 (France); Uzzo, M. [Computer Science Corporation, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dobrzycka, D. [European Southern Observatory, Karl Schwarzschild Strasse 2, D-85748 Garching (Germany)

    2015-01-01

    Comet C/2002 S2, a member of the Kreutz family of sungrazing comets, was discovered in white-light images of the Large Angle and Spectromeric Coronagraph Experiment coronagraph on the Solar and Heliospheric Observatory (SOHO) on 2002 September 18 and observed in H I Lyα emission by the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) instrument at four different heights as it approached the Sun. The H I Lyα line profiles detected by UVCS are analyzed to determine the spectral parameters: line intensity, width, and Doppler shift with respect to the coronal background. Two-dimensional comet images of these parameters are reconstructed at the different heights. A novel aspect of the observations of this sungrazing comet data is that, whereas the emission from most of the tail is blueshifted, that along one edge of the tail is redshifted. We attribute these shifts to a combination of solar wind speed and interaction with the magnetic field. In order to use the comet to probe the density, temperature, and speed of the corona and solar wind through which it passes, as well as to determine the outgassing rate of the comet, we develop a Monte Carlo simulation of the H I Lyα emission of a comet moving through a coronal plasma. From the outgassing rate, we estimate a nucleus diameter of about 9 m. This rate steadily increases as the comet approaches the Sun, while the optical brightness decreases by more than a factor of 10 and suddenly recovers. This indicates that the optical brightness is determined by the lifetimes of the grains, sodium atoms, and molecules produced by the comet.

  16. Paper-Thin Plastic Film Soaks Up Sun to Create Solar Energy

    Science.gov (United States)

    2006-01-01

    A non-crystallized silicon known as amorphous silicon is the semiconductor material most frequently chosen for deposition, because it is a strong absorber of light. According to the U.S. Department of Energy, amorphous silicon absorbs solar radiation 40 times more efficiently than single-crystal silicon, and a thin film only about 1-micrometer (one one-millionth of a meter) thick containing amorphous silicon can absorb 90 percent of the usable light energy shining on it. Peak efficiency and significant reduction in the use of semiconductor and thin film materials translate directly into time and money savings for manufacturers. Thanks in part to NASA, thin film solar cells derived from amorphous silicon are gaining more and more attention in a market that has otherwise been dominated by mono- and poly-crystalline silicon cells for years. At Glenn Research Center, the Photovoltaic & Space Environments Branch conducts research focused on developing this type of thin film solar cell for space applications. Placing solar cells on thin film materials provides NASA with an attractively priced solution to fabricating other types of solar cells, given that thin film solar cells require significantly less semiconductor material to generate power. Using the super-lightweight solar materials also affords NASA the opportunity to cut down on payload weight during vehicle launches, as well as the weight of spacecraft being sent into orbit.

  17. Resolving Azimuth Ambiguity Using Vertical Nature of Solar Quiet-Sun Magnetic Fields

    CERN Document Server

    Gosain, Sanjay

    2012-01-01

    The measurement of solar magnetic fields using the Zeeman effect diagnostics has a fundamental 180 degree ambiguity in the determination of the azimuth angle of the transverse field component. There are several methods that are used in the community and each one has its merits and demerits. Here we present a disambiguation idea that is based on the assumption that most of the magnetic field on the sun is predominantly vertical. While the method is not applicable to penumbra or other features harboring predominantly horizontal fields like the sheared neutral lines, it is useful for regions where fields are predominantly vertical like network and plage areas. The method is tested with the full-disk solar vector magnetograms observed by the VSM/SOLIS instrument. We find that statistically about 60-85 % of the pixels in a typical full-disk magnetogram has field inclination in the range of 0-30 degrees with respect to the local solar normal, and thus can be successfully disambiguated by the proposed method. Due to...

  18. Testing the Solar Probe Cup, an Instrument Designed to Touch the Sun

    Science.gov (United States)

    Whittlesey, Phyllis L.; Case, Anthony W.; Kasper, Justin Christophe; Wright, Kenneth H., Jr.; Alterman, Ben; Cirtain, Jonathan W.; Bookbinder, Jay; Korreck, Kelly E.; Stevens, Michael Louis

    2014-01-01

    Solar Probe Plus will be the first, fastest, and closest mission to the sun, providing the first direct sampling of the sub-Alfvenic corona. The Solar Probe Cup (SPC) is a unique re-imagining of the traditional Faraday Cup design and materials for immersion in this high temperature environment. Sending an instrument of this type into a never-seen particle environment requires extensive characterization prior to launch to establish sufficient measurement accuracy and instrument response. To reach this end, a slew of tests for allowing SPC to see ranges of appropriate ions and electrons, as well as a facility that reproduces solar photon spectra and fluxes for this mission. Having already tested the SPC at flight like temperatures with no significant modification of the noise floor, we recently completed a round of particle testing to see if the deviations in Faraday Cup design fundamentally change the operation of the instrument. Results and implications from these tests will be presented, as well as performance comparisons to cousin instruments such as those on the WIND spacecraft.

  19. The effects of the Reimers η on the solar rotational period when our Sun evolves to the RGB tip

    Science.gov (United States)

    Guo, Jianpo; Lin, Ling; Bai, Chunyan; Liu, Jinzhong

    2017-01-01

    Our Sun will expand enormously and lose substantial mass via a stellar wind during the red giant branch (RGB) phase; the rotational period will be prolonged by several orders of magnitude. It is difficult to predict how much mass the Sun will lose before it reaches the RGB tip. Therefore, the solar rotational period at the RGB tip is also quite indeterminate. In this work, the Sun is considered as a two-component system comprised of a core and a convective envelope, each being allowed to rotate freely. The angular momentum transfer from the inner planets to the solar envelope is taken into consideration. Using Eggleton's stellar evolution code, we study how the solar rotational period at the RGB tip depends on the value of Reimers η chosen. The solar envelope's rotational period at the RGB tip varies from 1 792 to 736 934 years, as the Reimers η is changed from 0.00 to 0.75. Recent observations show that the average Reimers η of Sun-like stars is 0.477. Adopting this average value of the Reimers η, the solar envelope's rotational period at the RGB tip will be 24 868 years. We also show how the envelope's rotational evolves with age and luminosity. Other Sun-like stars, with different planetary configurations, may prematurely eject mass and lead to planetary nebulae, if they engulf a brown-dwarf companion at the RGB tip. Swallowing a planet with 13 Jupiter masses and a 3-day orbit, a Sun-like star can become a rapidly rotating giant star.

  20. Solar power satellites: our next generation of satellites will deliver the sun's energy to Earth

    Science.gov (United States)

    Flournoy, Don M.

    2009-12-01

    The paper addresses the means for gathering energy from sunlight in space and transmitting it to Earth via Solar Power Satellites. The motivating factor is that the output of our sun is the largest potential energy source available, with the capability of providing inexhaustible quantities of clean electrical energy to every location on Earth. The challenge is that considerable financial, intellectual and diplomatic resources must be focused on designing and implementing new types of energy infrastructures in space and on the ground. These include: 1) next-generation space platforms, arrays, and power transmission systems; 2) more flexible and powerful launch vehicles for delivering materials to space; 3) specialized receivers, converters and storage systems on earth, and the in-orbit position allocations, spectrum and software that make these systems work together efficiently and safely.

  1. Harnessing the sun. The economics of solar photovoltaic electricity in East Africa

    Energy Technology Data Exchange (ETDEWEB)

    Ondraczek, Janosch

    2014-08-29

    could not do in my own work. The focus of this thesis is on solar energy technologies, as these have progressed most rapidly in recent years and as the (physical) potential to use the sun's energy is especially large in (East) Africa (Mandelli et al., 2014). Furthermore, solar energy technologies (particularly solar photovoltaics, or solar PV) have already been adopted on a larger scale in many developing countries in Africa and elsewhere (as well as developed countries, where they are being used to an even larger scale). For my research, this means that there were at least some data, history of market development, technology policies and evidence from previous research to work with. The overall contribution of my work is two-fold: First, I address specific research questions of relevance to both researchers and policymakers; and second, I do this in the context of a continent that is in many ways under-researched. According to Das et al. (2013) only around 3% of peer-reviewed papers in leading economics journals deal with sub-Saharan Africa, despite the fact that it accounts for some 12% of the global population (World Bank, 2010). In this context, the potential and future role of solar energy technologies for African development is one important aspect that is not yet fully understood. Helping to address this knowledge gap and advancing the knowledge frontier consequently seems of great relevance for informed policy decisions on both sustainable development and climate change mitigation.

  2. HIGH PRECISION ABUNDANCES OF THE OLD SOLAR TWIN HIP 102152: INSIGHTS ON Li DEPLETION FROM THE OLDEST SUN

    Energy Technology Data Exchange (ETDEWEB)

    Monroe, TalaWanda R.; Melendez, Jorge; Tucci Maia, Marcelo; Freitas, Fabricio C. [Departamento de Astronomia do IAG/USP, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, 05508-900 Sao Paulo, SP (Brazil); Ramirez, Ivan [McDonald Observatory, The University of Texas at Austin, Austin, TX 78712 (United States); Yong, David; Asplund, Martin; Alves-Brito, Alan; Casagrande, Luca [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Bergemann, Maria [Max Planck Institute for Astrophysics, Postfach 1317, D-85741 Garching (Germany); Bedell, Megan; Bean, Jacob [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Lind, Karin [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Castro, Matthieu; Do Nascimento, Jose-Dias [Departamento de Fisica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Bazot, Michael, E-mail: tmonroe@usp.br [Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)

    2013-09-10

    We present the first detailed chemical abundance analysis of the old 8.2 Gyr solar twin, HIP 102152. We derive differential abundances of 21 elements relative to the Sun with precisions as high as 0.004 dex ({approx}<1%), using ultra high-resolution (R = 110,000), high S/N UVES spectra obtained on the 8.2 m Very Large Telescope. Our determined metallicity of HIP 102152 is [Fe/H] = -0.013 {+-} 0.004. The atmospheric parameters of the star were determined to be 54 K cooler than the Sun, 0.09 dex lower in surface gravity, and a microturbulence identical to our derived solar value. Elemental abundance ratios examined versus dust condensation temperature reveal a solar abundance pattern for this star, in contrast to most solar twins. The abundance pattern of HIP 102152 appears to be the most similar to solar of any known solar twin. Abundances of the younger, 2.9 Gyr solar twin, 18 Sco, were also determined from UVES spectra to serve as a comparison for HIP 102152. The solar chemical pattern of HIP 102152 makes it a potential candidate to host terrestrial planets, which is reinforced by the lack of giant planets in its terrestrial planet region. The following non-local thermodynamic equilibrium Li abundances were obtained for HIP 102152, 18 Sco, and the Sun: log {epsilon} (Li) = 0.48 {+-} 0.07, 1.62 {+-} 0.02, and 1.07 {+-} 0.02, respectively. The Li abundance of HIP 102152 is the lowest reported to date for a solar twin, and allows us to consider an emerging, tightly constrained Li-age trend for solar twin stars.

  3. Temporal Variation of Ca–K Line Profile of the Sun during the Solar Cycle 22 and 23

    Indian Academy of Sciences (India)

    G. Sindhuja; Jagdev Singh

    2015-03-01

    We obtained the Ca–K line profile of the Sun as a star since 1969 at the Kodaikanal Observatory (KO) and analysis of the data showed the need to delineate the role of different chromospheric features to the variations of solar irradiance. We, therefore, initiated a new methodology to make observations of Ca–K line profiles of the Sun as a function of latitude and integrated over the longitude on a daily basis since 1986. We have collected the data for about thousand days, spread over two solar cycles. Earlier data (before 1997) were recorded on the photographic film and later data using the CCD detector. The photographic film data were digitized and analysed along with the data obtained from CCD camera. From these data, we computed K1 and K2 widths for the Sun as a star, using all the observed line profiles as a function of latitude. In addition, we have analyzed the spectra of the whole Sun as a star obtained on some days and compared it with the results obtained from latitude spectra of the same day. The K1 and K2 widths of the Sun as a star derived from the KO data are compared with values determined from the observations made at other observatories to compare results from the new methodology of observations adopted by us and the earlier techniques. The average values of K1 width during the minimum period. of solar cycle 23 are smaller than those during the minimum period of cycle 22. Day-to-day variations in the K1 and K2 widths and plage areas may imply that irradiance variations occur not only due to large-scale solar activity, but also because of variations in some of the three types of network in quiet regions of the Sun. The variation in intensity of the plages can also cause day-to-day variations in widths.

  4. The SunShot Initiative’s 2030 Goal: 3¢ per Kilowatt Hour for Solar Electricity

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-12-01

    In 2011, when solar power comprised less than 0.1% of the U.S. electricity supply, the U.S. Department of Energy (DOE) launched the SunShot Initiative with the goal of making solar electricity cost-competitive with traditionally generated electricity by 2020 without subsidies. At the time, this meant reducing photovoltaic (PV) and concentrating solar power (CSP) prices by approximately 75% across the residential, commercial, and utility-scale sectors. For utility-scale solar, this target is a levelized cost of energy (LCOE) of 6¢ per kilowatt hour (kWh)1. Rapid progress has been made in accelerating achievement of these cost reductions, and DOE’s Solar Energy Technologies Office (SETO) sees clear pathways to meeting the SunShot 2020 cost targets on schedule.2 Enabled by the cost reductions to date, solar-generated electricity has become mainstream. In 2014 and 2015, solar represented about one-third of new electrical generating capacity installed in the United States Halfway through 2016, solar was supplying 1% of U.S. electricity demand and growing with an installed capacity of 30 gigawatts.

  5. Global Structure of Solar Wind Plasma Flux Output Near the Sun

    Institute of Scientific and Technical Information of China (English)

    魏奉思; 蔡红昌

    1994-01-01

    Based on the observational data for K-corona brightness,interplanetary scintillations (IPS) and the photosphere’s magnetic fields in the ten Carrington rotations,1733-1742,in 1983,the average global structures of solar wind mass,momentum and energy flux outputs,Fm,Fp and Fe,on the source surface (10Rs) near the sun have been discussed and compared with those of the magnetic fields on the photosphere New discoveries are:(i) there are the global structures similar to wave-like structures with bi-peak in Fm,Fp and Fe; (ii) global structures of Fm,Fp and Fe are closely associated with those of the magnetic fields on the photosphere:most large flux outputs concentrate near the magneto-neutral line (MN) regions,less in the polar corona (PC) regions and middle in the strong magnetic fields (SM) regions; (iii) frequency spectra of Fm,Fn and Fe are evidently different for MN,PC and SM regions which are located in the high,low and middle,respectively; (iv) the total output rates of solar wind mass,momentum and en

  6. Three-degree-of-freedom Parallel Manipulator to Track the Sun for Concentrated Solar Power Systems

    Institute of Scientific and Technical Information of China (English)

    ASHITHSHYAM R B; GHOSAL A

    2015-01-01

    In concentrated solar power(CSP) generating stations, incident solar energy is reflected from a large number of mirrors or heliostats to a faraway receiver. In typical CSP installations, the mirror needs to be moved about two axes independently using two actuators in series with the mirror effectively mounted at a single point. A three degree-of-freedom parallel manipulator, namely the 3-RPS parallel manipulator, is proposed to track the sun. The proposed 3-RPS parallel manipulator supports the load of the mirror, structure and wind loading at three points resulting in less deflection, and thus a much larger mirror can be moved with the required tracking accuracy and without increasing the weight of the support structure. The kinematics equations to determine motion of the actuated prismatic joints in the 3-RPS parallel manipulator such that the sun’s rays are reflected on to a stationary receiver are developed. Using finite element analysis, it is shown that for same sized mirror, wind loading and maximum deflection requirement, the weight of the support structure is between 15% and 60% less with the 3-RPS parallel manipulator when compared to azimuth-elevation or the target-aligned configurations.

  7. Transfer orbits to L4 with a solar sail in the Earth-Sun system

    Science.gov (United States)

    Farrés, Ariadna

    2017-08-01

    Solar sails are enablers for long interplanetary transfers, but also offer many advantages in Libration Point Orbits missions. The extra effect of the Solar Radiation Pressure allows a space vehicle, by changing the sail orientation, to be artificially displaced from the classical Lagrangian equilibrium points, L1 , … ,L5 , as well perturbed from the Lyapunov, Halo and Lissajous orbits that appear around them. Most of these equilibrium points are linearly unstable and have stable and unstable invariant manifolds associated with them. In this paper we explore the possibilities that these invariant manifolds offer to navigate in a natural way around a circular, restricted, three-body system. We take the Earth-Sun Restricted Three Body Problem as a model and, for different fixed sail orientations, we compute the stable and unstable manifolds associated with the equilibrium points of the system. We find natural trajectories that allow the vehicle to move around the family of equilibria in a controlled way and to go from a region close to L1 or L2 to a region close to L4.

  8. From the sun to the Galactic Center: dust, stars and black hole(s)

    Science.gov (United States)

    Fritz, Tobias

    2013-07-01

    The centers of galaxies are their own ultimate gravitational sinks. Massive black holes and star clusters as well as gas are especially likely to fall into the centers of galaxies by dynamical friction or dissipation. Many galactic centers harbor supermassive black holes (SMBH) and dense nuclear (star) clusters which possibly arrived there by these processes. Nuclear clusters can be formed in situ from gas, or from smaller star clusters which fall to the center. Since the Milky Way harbors both an SMBH and a nuclear cluster, both can be studied best in the Galactic Center (GC), which is the closest galactic nucleus to us. In Chapter 1, I introduce the different components of the Milky Way, and put these into the context of the GC. I then give an overview of relevant properties (e.g. star content and distribution) of the GC. Afterwards, I report the results of four different studies about the GC. In Chapter 2, I analyze the limitations of astrometry, one of the most useful methods for the study of the GC. Thanks to the high density of stars and its relatively small distance from us it is possible to measure the motions of thousands of stars in the GC with images, separated by few years only. I find two main limitations to this method: (1) for bright stars the not perfectly correctable distortion of the camera limits the accuracy, and (2) for the majority of the fainter stars, the main limitation is crowding from the other stars in the GC. The position uncertainty of faint stars is mainly caused by the seeing halos of bright stars. In the very center faint unresolvable stars are also important for the position uncertainty. In Chapter 3, I evaluate the evidence for an intermediate mass black hole in the small candidate cluster IRS13E within the GC. Intermediate mass black holes (IMBHs) have a mass between the two types of confirmed black hole: the stellar remnants and the supermassive black holes in the centers of galaxies. One possibility for! their formation is the

  9. Possible measurements of J sub 2 and the sun's angular momentum with the solar probe. [covariance analysis of solar quadrupole moment

    Science.gov (United States)

    Nordtvedt, K.

    1978-01-01

    The metric tensor is given for describing the dynamical effects of the sun on a solar probe and the gravitational redshift of a probe-based clock in a covariance analysis for the detectability of the solar quadrupole moment and the solar angular momentum. Unknown parameters were determined by least squares fit to the probe tracking data. A polar orbit was assumed with perihelion at 5 solar radii and with an earth-sun-probe angle of 135 deg at perihelion. Tracking was assumed to be Doppler only, with a basic uncertainity of .1 mm/sec in the radial velocity. A drag-free system which could reduce nongravitational forces below the level of 2 times 10 to the minus 12th power was found necessary to preserve this same level of accuracy. Both one way and two way Doppler were supposed in order to determine the gravitational redshift as well as the pure spacecraft dynamics.

  10. The effect of total solar eclipse on the daily activities of Nasalis larvatus (Wurmb.) in Mangrove Center, Kariangau, East Kalimantan

    Science.gov (United States)

    Sya Shanida, Sya; Hanik Lestari, Tiffany; Partasasmita, Ruhyat

    2016-11-01

    The total solar eclipse is an interesting phenomenon because the sun is covered by the moon. This phenomenon is like a night deception for animals, humans, and plants. One of the animals is Bekantan (Nasalis larvatus (Wurmb.)). Nasalis larvatus change its activity when this phenomenon occurs. The aims of the present study are (1) daily activity of Nasalis larvatus on total solar eclipse on March 9th, 2016 and (2) the effect of total solar eclipse on its activity in Mangrove Center, Kariangau, East Kalimantan. The adlibitum method was used in this study on Bekantan's adult female. The result shows that the total solar eclipse has considerable effect on the daily activity of Bekantan. During total solar eclipse, the activity of Bekantan significantly stopped. When the total solar eclipse finished, Bekantan started its daily activity, and it was indicated by feeding activity which was led by alfa-male.

  11. Seguidor Solar de Dos Ejes para un Horno Solar Two-Axis Sun Tracking System for a Solar Furnace

    OpenAIRE

    Gabriel Villeda; Alejandro Castañeda; José T Vega; Jorge Pineda

    2011-01-01

    Se presenta el diseño y fabricación de un seguidor solar de dos ejes (rotación-elevación), el cual controla un helióstato de un horno solar para la cocción de tabiques de arcilla. El sistema trabaja con motores controlados desde una computadora personal. El algoritmo para el seguidor solar se desarrolló en un lenguaje de programación visual, calcula los ángulos de seguimiento primario y secundario del helióstato y los despliega en una pantalla. El microcontrolador está programado para control...

  12. Capturing the Sun: A Roadmap for Navigating Data-Access Challenges and Auto-Populating Solar Home Sales Listings

    Energy Technology Data Exchange (ETDEWEB)

    Stukel, Laura [Elevate Energy, Chicago, IL (United States); Hoen, Ben [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Adomatis, Sandra [Adomatis Appraisal Services, Punta Gorda, FL (United States); Foley, Craig [Sustainable Real Estate Consulting Services, Somerville, MA (United States); Parsons, Laura [Center for Sustainable Energy, San Diego, CA (United States); James, Mark [Vermont Law School, South Royalton, VT (United States). Inst. for Energy and Environment; Mastor, Roxana-Andreea [Vermont Law School, South Royalton, VT (United States). Inst. for Energy and Environment; Wedewer, Lindsey [Colorado Energy Office, Denver, CO (United States)

    2017-04-13

    Capturing the Sun: A Roadmap for Navigating Data-Access Challenges and Auto-Populating Solar Home Sales Listings supports a vision of solar photovoltaic (PV) advocates and real estate advocates evolving together to make information about solar homes more accessible to home buyers and sellers and to simplify the process when these homes are resold. The Roadmap is based on a concept in the real estate industry known as automatic population of fields. Auto-population (also called auto-pop in the industry) is the technology that allows data aggregated by an outside industry to be matched automatically with home sale listings in a multiple listing service (MLS).

  13. Solar system a visual exploration of the planets, moons, and other heavenly bodies that orbit our sun

    CERN Document Server

    Chown, Marcus

    2011-01-01

    Based on the latest ebook sensation developed by Theodore Gray and his company Touch Press, this beautiful print book presents a new and fascinating way to experience the wonders of the solar system Following the stunning success of both the print edition and the app of The Elements, Black Dog & Leventhal and Touch Press have teamed up again. Solar System is something completely new under the sun. Never before have the wonders of our solar system—all its planets, dwarf planets, the sun, moons, rocky Asteroid Belt, and icy Kuiper Belt—been so immediately accessible to readers of all ages. Beginning with a fascinating overview and then organized by planet, in order of its distance from the sun, Solar System takes us on a trip across time and space that includes a front-row seat to the explosive birth of the solar system, a journey to (and then deep inside) each of its eight planets, and even an in-depth exploration of asteroids and comets. With hundreds of gorgeous images produced especially for this...

  14. Sodium reflux pool-boiler solar receiver on-sun test results

    Energy Technology Data Exchange (ETDEWEB)

    Andraka, C E; Moreno, J B; Diver, R B; Moss, T A [Oak Ridge National Lab., TN (United States)

    1992-06-01

    The efficient operation of a Stirling engine requires the application of a high heat flux to the relatively small area occupied by the heater head tubes. Previous attempts to couple solar energy to Stirling engines generally involved directly illuminating the heater head tubes with concentrated sunlight. In this study, operation of a 75-kW{sub t} sodium reflux pool-boiler solar receiver has been demonstrated and its performance characterized on Sandia's nominal 75-kW{sub t} parabolic-dish concentrator, using a cold-water gas-gap calorimeter to simulate Stirling engine operation. The pool boiler (and more generally liquid-metal reflux receivers) supplies heat to the engine in the form of latent heat released from condensation of the metal vapor on the heater head tubes. The advantages of the pool boiler include uniform tube temperature, leading to longer life and higher temperature available to the engine, and decoupling of the design of the solar absorber from the engine heater head. The two-phase system allows high input thermal flux, reducing the receiver size and losses, therefore improving system efficiency. The receiver thermal efficiency was about 90% when operated at full power and 800{degree}C. Stable sodium boiling was promoted by the addition of 35 equally spaced artificial cavities in the wetted absorber surface. High incipient boiling superheats following cloud transients were suppressed passively by the addition of small amounts of xenon gas to the receiver volume. Stable boiling without excessive incipient boiling superheats was observed under all operating conditions. The receiver developed a leak during performance evaluation, terminating the testing after accumulating about 50 hours on sun. The receiver design is reported here along with test results including transient operations, steady-state performance evaluation, operation at various temperatures, infrared thermography, x-ray studies of the boiling behavior, and a postmortem analysis.

  15. Ocular surface changes and tear film alterations associated with sun gazing during a solar eclipse.

    Science.gov (United States)

    Nepp, Johannes; Dorner, Guido T; Jandrasits, Kerstin; Maar, Noemi; Schild, Gebtraud; Wedrich, Andreas

    2003-01-31

    A solar eclipse occurred in central Europe on August 11th, 1999. Following the eclipse, patients with ocular symptoms were investigated. Gazing at the sun without protection is liable to damage the retina. Our attention was focused on changes of the ocular surface and the tear film. Forty-three patients were investigated within one week after the solar eclipse as baseline. 33 of them were followed up one year later. Visual acuity and the central visual-field were measured, and the ocular surface and the fundus were examined using a slit lamp. The quality of the lacrimal tear film was examined using Schirmer's test for the aqueous layer, break-up time for the mucous layer and interference observation for the lipid layer, measured by a slit lamp and a tearoscope. At the baseline 19 patients had non-specific visual problems. Pathological alterations of the tear film were seen in all three tear-film layers: Schirmer's test was pathological in 87%, break-up time decreased in 85%, the interference pattern of the lipid layer changed in 67% and there were changes in 87% using the tearoscope. One year later the non specific visual disorders had disappeared. Schirmer's test did not reveal much change from the baseline: 51% pathological, 24% remained pathological in break-up-time and the lipid layer was normalized except in 9%. Using the tearoscope, lipids were better than grade 3 in all patients. After gazing at a solar eclipse the ocular surface and tear film changed. While the aqueous layer remained pathological in many patients, the lipid layer and the mucous layer recovered spontaneously.

  16. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere VII. Further Insights into the Chromosphere and Corona

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available In the liquid metallic hydrogen model of the Sun, the chromosphere is responsible for the capture of atomic hydrogen in the solar atmosphere and its eventual re-entry onto the photospheric surface (P.M. Robitaille. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere IV. On the Nature of the Chromosphere. Prog. Phys., 2013, v. 3, L15–L21. As for the corona, it represents a diffuse region containing both gaseous plasma and condensed matter with elevated electron affinity (P.M. Robitaille. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere V. On the Nature of the Corona. Prog. Phys., 2013, v. 3, L22–L25. Metallic hydrogen in the corona is thought to enable the continual harvest of electrons from the outer reaches of the Sun, thereby preserving the neutrality of the solar body. The rigid rotation of the corona is offered as the thirty-third line of evidence that the Sun is comprised of condensed matter. Within the context of the gaseous models of the Sun, a 100 km thick transition zone has been hypothesized to exist wherein temperatures increase dramatically from 104–106 K. Such extreme transitional temperatures are not reasonable given the trivial physical scale of the proposed transition zone, a region adopted to account for the ultra-violet emission lines of ions such as C IV, O IV, and Si IV. In this work, it will be argued that the transition zone does not exist. Rather, the intermediate ionization states observed in the solar atmosphere should be viewed as the result of the simultaneous transfer of protons and electrons onto condensed hydrogen structures, CHS. Line emissions from ions such as C IV, O IV, and Si IV are likely to be the result of condensation reactions, manifesting the involvement of species such as CH4, SiH4, H3O+ in the synthesis of CHS in the chromosphere. In addition, given the presence of a true solar surface at the level of the photosphere in the liquid metallic hydrogen model

  17. Solar magnetic field studies using the 12 micron emission lines. I - Quiet sun time series and sunspot slices

    Science.gov (United States)

    Deming, Drake; Boyle, Robert J.; Jennings, Donald E.; Wiedemann, Gunter

    1988-01-01

    The use of the extremely Zeeman-sensitive IR emission line Mg I, at 12.32 microns, to study solar magnetic fields. Time series observations of the line in the quiet sun were obtained in order to determine the response time of the line to the five-minute oscillations. Based upon the velocity amplitude and average period measured in the line, it is concluded that it is formed in the temperature minimum region. The magnetic structure of sunspots is investigated by stepping a small field of view in linear 'slices' through the spots. The region of penumbral line formation does not show the Evershed outflow common in photospheric lines. The line intensity is a factor of two greater in sunspot penumbrae than in the photosphere, and at the limb the penumbral emission begins to depart from optical thinness, the line source function increasing with height. For a spot near disk center, the radial decrease in absolute magnetic field strength is steeper than the generally accepted dependence.

  18. SunShot Prize: America's Most Affordable Rooftop Solar: A Competition To Spur Low-Cost Rooftop Solar Installations Across The Nation (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-06-01

    The SunShot Prize encourages novel public-private partnerships, original business models, and innovative approaches to installing clean, renewable solar energy. The sustainable business strategies developed by participants will provide transferable lessons that can be applied nationwide to hasten America's transition to affordable clean energy in a post-subsidy market.

  19. On the Path to SunShot. Advancing Concentrating Solar Power Technology, Performance, and Dispatchability

    Energy Technology Data Exchange (ETDEWEB)

    Mehos, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ho, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-05-01

    This report examines the remaining challenges to achieving the competitive concentrating solar power (CSP) costs and large-scale deployment envisioned under the U.S. Department of Energy's SunShot Initiative. Although CSP costs continue to decline toward SunShot targets, CSP acceptance and deployment have been hindered by inexpensive photovoltaics (PV). However, a recent analysis found that thermal energy storage (TES) could increase CSP's value--based on combined operational and capacity benefits--by up to 6 cents/kWh compared to variable-generation PV, under a 40% renewable portfolio standard in California. Thus, the high grid value of CSP-TES must be considered when evaluating renewable energy options. An assessment of net system cost accounts for the difference between the costs of adding new generation and the avoided cost from displacing other resources providing the same level of energy and reliability. The net system costs of several CSP configurations are compared with the net system costs of conventional natural-gas-fired combustion-turbine (CT) and combined-cycle plants. At today's low natural gas prices and carbon emission costs, the economics suggest a peaking configuration for CSP. However, with high natural gas prices and emission costs, each of the CSP configurations compares favorably against the conventional alternatives, and systems with intermediate to high capacity factors become the preferred alternatives. Another analysis compares net system costs for three configurations of CSP versus PV with batteries and PV with CTs. Under current technology costs, the least-expensive option is a combination of PV and CTs. However, under future cost assumptions, the optimal configuration of CSP becomes the most cost-effective option.

  20. Gravitational Lensing Characteristics of the Transparent Sun

    CERN Document Server

    Patla, Bijunath

    2007-01-01

    The transparent Sun is modeled as a spherically symmetric and centrally condensed gravitational lens using recent Standard Solar Model (SSM) data. The Sun's minimum focal length is computed to a refined accuracy of 23.5 +/- 0.1 AU, just beyond the orbit of Uranus. The Sun creates a single image of a distant point source visible to observers inside this minimum focal length and to observers sufficiently removed from the line connecting the source through the Sun's center. Regions of space are mapped where three images of a distant point source are created, along with their associated magnifications. Solar caustics, critical curves, and Einstein rings are computed and discussed. Extremely high gravitational lens magnifications exist for observers situated so that an angularly small, unlensed source appears near a three-image caustic. Types of radiations that might undergo significant solar lens magnifications as they can traverse the core of the Sun, including neutrinos and gravitational radiation, are discusse...

  1. Advanced nanostructured materials and their application for improvement of sun-light harvesting and efficiency of solar cells

    Science.gov (United States)

    Dimova-Malinovska, D.

    2016-02-01

    This review describes the application of different nanostructured materials in solar cells technology for improvement of sun-light harvesting and their efficiency. Several approaches have recently been proposed to increase the efficiency of solar cells above the theoretical limit which are based on a “photon management” concept that employs such phenomena as: (i) down-conversion, and (ii) surface plasmon resonance effect (iii) decreasing of the loss due to the reflection of the radiation, (iv) increasing of the reflection from the back contact, v) increasing of the effective solar cells surface, etc. The results demonstrate the possibility for to increasing of light harvesting, short circuit current and efficiency by application of nanomaterials in thin film and hetero-junction (HJ) solar cells. The first promising results allow an expectation for application of advanced nanomaterials in the 3d generation solar cells.

  2. Strength distribution of solar magnetic fields in photospheric quiet Sun regions

    Science.gov (United States)

    Ramírez Vélez, J. C.; López Ariste, A.; Semel, M.

    2008-08-01

    Context: The magnetic topology of the solar photosphere in its quietest regions is hidden by the difficulties to disentangle magnetic flux through the resolution element from the field strength of unresolved structures. The observation of spectral lines with strong coupling with hyperfine structure, like the observed Mn i line at 553.7 nm, allows such differentiation. Aims: To analyse the distribution of field strengths in the network and intranetwork of the solar photosphere through inversion of the Mn i line at 553.7 nm. Methods: An inversion code for the magnetic field using the principal component analysis (PCA) has been developed. Statistical tests are run on the code to validate it. The code has to draw information from the small-amplitude spectral feature appearing in the core of the Stokes V profile of the observed line for field strengths below a certain threshold, coinciding with lower limit of the Paschen-Back effect in the fine structure of the involved atomic levels. Results: The inversion of the observed profiles, using the circular polarisation (V) and the intensity (I), shows the presence of magnetic fields strengths in a range from 0 to 2 kG, with predominant weak strength values. Mixed regions with mean strength field values of 1130 and 435 Gauss are found associated with the network and intranetwork, respectively. Conclusions: The Mn i line at 553 nm probes the field strength distribution in the quiet sun and shows the predominance of weak, hectoGauss fields in the intranetwork, and strong, kiloGauss fields in the network. It also shows that both network and intranetwork are to be understood at our present spatial resolutions as field distributions, of which we hint at the mean properties.

  3. Ulysses and IMP-8 Observations of Cosmic Rays and So-lar Energetic Particles from the South Pole to the North Pole of the Sun near Solar Maximum*

    Science.gov (United States)

    McKibben, R. B.; Connell, J. J.; Lopate, C.; Zhang, M.

    2001-12-01

    The High Energy Telescope (HET) of the Ulysses COSPIN experiment measures intensities of galactic cosmic rays and solar energetic particles (SEPs) with good energy and charge resolution at energies above about 30 MeV/n. Since passing over the South Polar regions of the Sun near solar maximum in late 2000 Ulysses has been rapidly traversing solar latitude in its so-called Fast Latitude Scan (FLS), passing through perihelion near the sun's equator in May 2001. Maximum northern latitude (80.2 deg N) will be reached in October 2001. HET observations since the onset of solar activity, including the South Polar pass and the first part of the FLS, show that SEPs from large events were commonly observed at both Ulysses and Earth (IMP-8) regardless of the radial, latitudinal, or longitudinal separations between Ulysses and Earth. During the decay phases of the events intensities were often almost equal at Ulysses and IMP, even when Ulysses was over the Sun's South Pole and the associated flare site was in the northern hemisphere. This suggests that propagation of particles across the average interplanetary magnetic field in the inner heliosphere is effective enough to relax longitudinal and latitudinal particle intensity gradients within a few days. For galactic cosmic rays, observations from the FLS so far show that latitudinal gradients resulting from solar modulation at solar maximum are sun's North Polar Regions, and discuss the significance of the results for models of energetic charged particle propagation through the heliosphere. * This work was supported in part by NASA Contract JPL-955432 and by NASA Grant NAG5-8032.

  4. First on-sun test of NaK pool-boiler solar receiver

    Science.gov (United States)

    Moreno, J. B.; Andraka, C. E.; Moss, T. A.; Cordeiro, P. G.; Dudley, V. E.; Rawlinson, K. S.

    During 1989-1990, a refluxing liquid-metal pool-boiler solar receiver designed for dish/Stirling application at 75 kW(sub t) throughput was successfully demonstrated at Sandia National Laboratories. Significant features of this receiver included (1) boiling sodium as the heat transfer medium, and (2) electric-discharge-machined (EDM) cavities as artificial nucleation sites to stabilize boiling. Following this first demonstration, a second-generation pool-boiler receiver that brings the concept closer to commercialization has been designed, constructed, and successfully tested. For long life, the new receiver is built from Haynes Alloy 230. For increased safety factors against film boiling and flooding, the absorber area and vapor-flow passages have been enlarged. To eliminate the need for trace heating, sodium has been replaced by the sodium-potassium alloy NaK-78. To reduce manufacturing costs, the receiver has a powdered-metal coating instead of EDM cavities for stabilization of boiling. To control incipient-boiling superheats, especially during hot restarts, it contains a small amount of xenon. In this paper, we present the receiver design and report the results of on-sun tests using a nominal 75 kW(sub t) test-bed concentrator to characterize boiling stability, hot-restart behavior, and thermal efficiency at temperatures up to 750 C. We also report briefly on late results from an advanced-concepts pool-boiler receiver.

  5. Forty Lines of Evidence for Condensed Matter — The Sun on Trial: Liquid Metallic Hydrogen as a Solar Building Block

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-10-01

    Full Text Available Our Sun has confronted humanity with overwhelming evidence that it is comprised of condensed matter. Dismissing this reality, the standard solar models continue to be anchored on the gaseous plasma. In large measure, the endurance of these theories can be attributed to 1 the mathematical elegance of the equations for the gaseous state, 2 the apparent success of the mass-luminosity relationship, and 3 the long-lasting influence of leading proponents of these models. Unfortunately, no direct physical finding supports the notion that the solar body is gaseous. Without exception, all observations are most easily explained by recognizing that the Sun is primarily comprised of condensed matter. However, when a physical characteristic points to condensed matter, a postori arguments are invoked to account for the behavior using the gaseous state. In isolation, many of these treatments appear plausible. As a result, the gaseous models continue to be accepted. There seems to be an overarching belief in solar science that the problems with the gaseous models are few and inconsequential. In reality, they are numerous and, while often subtle, they are sometimes daunting. The gaseous equations of state have introduced far more dilemmas than they have solved. Many of the conclusions derived from these approaches are likely to have led solar physics down unproductive avenues, as deductions have been accepted which bear little or no relationship to the actual nature of the Sun. It could be argued that, for more than 100 years, the gaseous models have prevented mankind from making real progress relative to understanding the Sun and the universe. Hence, the Sun is now placed on trial. Forty lines of evidence will be presentedbthat the solar body is comprised of, and surrounded by, condensed matter. These ‘proofs’ can be divided into seven broad categories: 1 Planckian, 2 spectroscopic, 3 structural, 4 dynamic, 5 helioseismic, 6 elemental, and 7 earthly

  6. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere V. On the Nature of the Corona

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available The E-corona is the site of numerous emission lines associated with high ionization states (i.e. FeXIV-FeXXV. Modern gaseous models of the Sun require that these states are produced by atomic irradiation, requiring the sequential removal of electrons to infinity, without an associated electron acceptor. This can lead to computed temperatures in the corona which are unrealistic (i.e. ∼30–100 MK contrasted to solar core values of ∼16 MK. In order to understand the emission lines of the E-corona, it is vital to recognize that they are superimposed upon the K-corona, which produces a continuous spectrum, devoid of Fraunhofer lines, arising from this same region of the Sun. It has been advanced that the K-corona harbors self-luminous condensed matter (Robitaille P.M. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere II. Continuous Emission and Condensed Matter Within the Corona. Progr. Phys., 2013, v. 3, L8–L10; Robitaille P.M. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere III. Importance of Continuous Emission Spectra from Flares, Coronal Mass Ejections, Prominences, and Other Coronal Structures. Progr. Phys., 2013, v. 3, L11–L14. Condensed matter can possess elevated electron affinities which may strip nearby atoms of their electrons. Such a scenario accounts for the high ionization states observed in the corona: condensed matter acts to harness electrons, ensuring the electrical neutrality of the Sun, despite the flow of electrons and ions in the solar winds. Elevated ionization states reflect the presence of materials with high electron affinities in the corona, which is likely to be a form of metallic hydrogen, and does not translate into elevated temperatures in this region of the solar atmosphere. As a result, the many mechanisms advanced to account for coronal heating in the gaseous models of the Sun

  7. The effects of oblateness and solar radiation pressure on halo orbits in the photogravitational Sun-Earth system

    Science.gov (United States)

    Srivastava, Vineet K.; Kumar, Jai; Kushvah, Badam Singh

    2016-12-01

    In this paper, we construct a third-order analytic approximate solution using the Lindstedt-Poincare method in the photogravitational circular restricted three body problem considering the Sun as a radiating source and the Earth as an oblate spheroid for computing halo orbits around the collinear Lagrangian points L1 and L2. Further, the well-known differential correction and continuation schemes are used to compute halo orbits and their families numerically. The effects of solar radiation pressure and oblateness on the orbit are studied around both Lagrangian points. From the study, it is noticed that time period of the halo orbit increases around L1 and L2 accounting oblateness of the Earth and solar radiation pressure of the Sun. It is also found that stability of halo orbits is a weak function of the out-of-plane amplitude and mass reduction factor.

  8. NASA Sun-Earth Connections Theory Program: The Structure and Dynamics of the Solar Corona and Inner Heliosphere

    Science.gov (United States)

    Mikic, Zoran; Grebowsky, Joseph M. (Technical Monitor)

    2001-01-01

    This report covers technical progress during the fourth quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation, and covers the period May 16,2001 to August 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model.

  9. Broadband Radio Spectral Observations of Solar Eclipse on 2008-08-01 and Implications on the Quiet Sun Atmospheric Model

    CERN Document Server

    Tan, Baolin; Zhang, Yin; Tan, Chengmin; Huang, Jing; Liu, Yuying; Fu, Qijun; Chen, ZhiJun; Liu, Fei; Chen, Linjie; Ji, Guoshu; 10.1007/s11433-009-0230-y

    2009-01-01

    Based on the joint-observations of the radio broadband spectral emissions of solar eclipse on August 1, 2008 at Jiuquan (total eclipse) and Huairou (partial eclipse) at the frequencies of 2.00 -- 5.60 GHz (Jiuquan), 2.60 -- 3.80 GHZ (Chinese solar broadband radiospectrometer, SBRS/Huairou), and 5.20 -- 7.60 GHz (SBRS/Huairou), the authors assemble a successive series of broadband spectrum with a frequency of 2.60 -- 7.60 GHz to observe the solar eclipse synchronously. This is the first attempt to analyze the solar eclipse radio emission under the two telescopes located at different places with broadband frequencies in the periods of total and partial eclipse. With these analyses, the authors made a new semiempirical model of the coronal plasma density of the quiet Sun and made a comparison with the classic models.

  10. Chemical Impact of Solar Energetic Particle Event From The Young Sun: Implications for the Origin of Prebiotic Chemistry and the Fain Young Sun Paradox

    Science.gov (United States)

    Airapetian, V.; Gronoff, G.; Hébrard, E.; Danchi, W.

    2015-12-01

    Understanding how the simple molecules present on the early Earth and possibly Mars may have set a path for complex biological molecules, the building blocks of life, represents one of greatest unsolved questions. Here we present a new model of the rise of the abiotic nitrogen fixation and associated pre-biotic chemistry in the early Earth and Mars atmosphere mediated by solar eruptive events. Our physical models of interaction of magnetic clouds ejected from the young Sun with magnetospheres of the early Earth show significant perturbations of geomagnetic fields that produce extended polar caps. These polar caps provide pathways for energetic particles associated with magnetic clouds to penetrate into the nitrogen-rich weakly reducing atmosphere and initiate the reactive chemistry by breaking molecular nitrogen, carbon dioxide, methane and producing hydrogen cyanide, the essential compound for life. The model also shows that contrary to the current models of warming of early Earth and Mars, major atmospheric constituents, CO2 and CH4 will be destroyed due to collisional dissociation with energetic particles. Instead, efficient formation of the potent greenhouse gas, nitrous oxide, as a by-product of these processes is expected. This mechanism can consistently explain the Faint Young Sun's paradox for the early atmospheres of Earth and Mars. Our new model provides insight into how life may have initiated on Earth and Mars and how to search for the spectral signatures on planets "pregnant" with the potential for life.

  11. The "Sun-climate" relationship : III. The solar flares, north-south sunspot arrea asymmetry and climate

    CERN Document Server

    Komitov, Boris

    2010-01-01

    In this last Paper III additional evidences that the solar high energetic particles radiation with energies higher as 100 MeV (the solar cosmic rays SCR) is an very important component for the "Sun- climate" relationship are given (see also Paper I and II). The total solar irradiance (TSI) and the galactic cosmic rays (GCR) variations given an integral climate effect of cooling in sunspot minima and warming in the sunspot maxima. Unlike the both ones the powerful solar corpuscular events plays a cooling climate role during the epochs of their heigh levels. By this one subcenturial global and regional temperature quasi- cyclic changes by duration of approximately 60 years could be track during the last 150 years of instrumental climate observations . It has been also evided in the paper that this subcenturial oscilation is very important in the Group sunspot number (GSN) data series since the Maunder minimum up to the end of 20th century. Thus the solar erruptive activity effect make the total "Sun -climate" r...

  12. Towards a Solution to the Early Faint Sun Paradox: A Lower Cosmic Ray Flux from a Stronger Solar Wind

    CERN Document Server

    Shaviv, N J

    2003-01-01

    The solar luminosity obtained in standard solar models should have gradually increased by about 30% over the past 4.5 billion years. Under the faint sun, Earth should have been frozen solid for most of its existence. Yet, running water is observed to have been present since very early in Earth's history. This enigma is known as the faint sun paradox. We show here that it can be significantly extenuated once we consider the cooling effect that cosmic rays are suspected to have on the global climate and that the younger sun must have had a stronger solar wind, such that it was more effective at stopping cosmic rays from reaching Earth. We therefore find that even modest greenhouse warming in sufficient to completely resolve the paradox. When coupled to the variable star formation rate in the Milky Way, we recover that the past Eon and the Eon between 2 and 3 Gyr before present should have had glaciations, while others not. As to the future, we find that without human intervention, the average global temperature...

  13. Graphene oxide-based efficient and scalable solar desalination under one sun with a confined 2D water path.

    Science.gov (United States)

    Li, Xiuqiang; Xu, Weichao; Tang, Mingyao; Zhou, Lin; Zhu, Bin; Zhu, Shining; Zhu, Jia

    2016-12-06

    Because it is able to produce desalinated water directly using solar energy with minimum carbon footprint, solar steam generation and desalination is considered one of the most important technologies to address the increasingly pressing global water scarcity. Despite tremendous progress in the past few years, efficient solar steam generation and desalination can only be achieved for rather limited water quantity with the assistance of concentrators and thermal insulation, not feasible for large-scale applications. The fundamental paradox is that the conventional design of direct absorber-bulk water contact ensures efficient energy transfer and water supply but also has intrinsic thermal loss through bulk water. Here, enabled by a confined 2D water path, we report an efficient (80% under one-sun illumination) and effective (four orders salinity decrement) solar desalination device. More strikingly, because of minimized heat loss, high efficiency of solar desalination is independent of the water quantity and can be maintained without thermal insulation of the container. A foldable graphene oxide film, fabricated by a scalable process, serves as efficient solar absorbers (>94%), vapor channels, and thermal insulators. With unique structure designs fabricated by scalable processes and high and stable efficiency achieved under normal solar illumination independent of water quantity without any supporting systems, our device represents a concrete step for solar desalination to emerge as a complementary portable and personalized clean water solution.

  14. Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

    Directory of Open Access Journals (Sweden)

    R. B. McKibben

    Full Text Available In 2000–2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum.  Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but clear latitude gradients were observed during the similar phase of Ulysses’ orbit near the 1994–95 solar minimum. At proton energies above ~10 MeV and extending up to >70 MeV, the intensities are often dominated by Solar Energetic Particles (SEPs accelerated near the Sun in association with intense solar flares and large Coronal Mass Ejections (CMEs. At lower energies the particle intensities are almost constantly enhanced above background, most likely as a result of a mix of SEPs and particles accelerated by interplanetary shocks. Simultaneous high-latitude Ulysses and near-Earth observations show that most events that produce large flux increases near Earth also produce flux increases at Ulysses, even at the highest latitudes attained. Particle anisotropies during particle onsets at Ulysses are typically directed outwards from the Sun, suggesting either acceleration extending to high latitudes or efficient cross-field propagation somewhere inside the orbit of Ulysses. Both cosmic ray and SEP observations are consistent with highly efficient transport of energetic charged particles between the equatorial and polar regions and across the mean interplanetary magnetic fields in the inner heliosphere.

    Key words. Interplanetary physics (cosmic rays – Solar physics, astrophysics and astronomy (energetic particles; flares and mass ejections

  15. Sun-Relative Pointing for Dual-Axis Solar Trackers Employing Azimuth and Elevation Rotations

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hansen, Clifford W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-12-30

    Dual axis trackers employing azimuth and elevation rotations are common in the field of photovoltaic (PV) energy generation. Accurate sun-tracking algorithms are widely available. However, a steering algorithm has not been available to accurately point the tracker away from the sun such that a vector projection of the sun beam onto the tracker face falls along a desired path relative to the tracker face. We have developed an algorithm which produces the appropriate azimuth and elevation angles for a dual axis tracker when given the sun position, desired angle of incidence, and the desired projection of the sun beam onto the tracker face. Development of this algorithm was inspired by the need to accurately steer a tracker to desired sun-relative positions in order to better characterize the electro-optical properties of PV and CPV modules.

  16. Charge States and FIP Bias of the Solar Wind from Coronal Holes, Active Regions, and Quiet Sun

    Science.gov (United States)

    Fu, Hui; Madjarska, Maria S.; Xia, LiDong; Li, Bo; Huang, ZhengHua; Wangguan, Zhipeng

    2017-02-01

    Connecting in situ measured solar-wind plasma properties with typical regions on the Sun can provide an effective constraint and test to various solar wind models. We examine the statistical characteristics of the solar wind with an origin in different types of source regions. We find that the speed distribution of coronal-hole (CH) wind is bimodal with the slow wind peaking at ∼400 km s‑1 and the fast at ∼600 km s‑1. An anti-correlation between the solar wind speeds and the O7+/O6+ ion ratio remains valid in all three types of solar wind as well during the three studied solar cycle activity phases, i.e., solar maximum, decline, and minimum. The {N}{Fe}/{N}{{O}} range and its average values all decrease with the increasing solar wind speed in different types of solar wind. The {N}{Fe}/{N}{{O}} range (0.06–0.40, first ionization potential (FIP) bias range 1–7) for active region wind is wider than for CH wind (0.06–0.20, FIP bias range 1–3), while the minimum value of {N}{Fe}/{N}{{O}} (∼ 0.06) does not change with the variation of speed, and it is similar for all source regions. The two-peak distribution of CH wind and the anti-correlation between the speed and O7+/O6+ in all three types of solar wind can be explained qualitatively by both the wave-turbulence-driven and reconnection-loop-opening (RLO) models, whereas the distribution features of {N}{Fe}/{N}{{O}} in different source regions of solar wind can be explained more reasonably by the RLO models.

  17. Fabrication of large-format holograms in dichromated gelatin films for sun control and solar concentrators

    Science.gov (United States)

    Stojanoff, Christo G.; Schuette, Hartmut; Schulat, Jochen; Kubiza, Ralf; Froening, Philipp

    1997-05-01

    Dichromated gelatin layers (DCG) facilitate the design and fabrication of large format holographic optical elements (HOE) of high optical quality and diffraction efficiency. The HOEs are used for the fabrication of spectrally selective solar concentrators and as glazing materials for daylighting and passive sun control in buildings. The suitability of HOEs in these applications depends upon the achievable bandwidth, operating central wavelength, dispersion characteristics and low absorption losses. The HOEs are fabricated on glass or plastic film substrata in a DCG-layer of 5 to 30 micrometer thickness. The layer thickness and the gradient ar precisely controlled during the layer deposition and drying (plus or minus 1 micrometer and 0.1 micrometer/cm for standard layer of 10 micrometer thickness). The production process is based on the fabrication of high quality master holograms that are copied by dry copying procedure. The current manufacturing facilities allow the fabrication of 1 m2 HOEs on glass substratum and a continuous production of HOEs on plastic substratum with a width of 20 cm and length of 50 m. This technology is also used to fabricate holograms for instrumentation optics in metrology and for optical interconnects in multichip modules. The fabricated HOEs exhibit the desired operational characteristics: high diffraction efficiency, small Braggshift, large bandwidth and a central wavelength that may be freely selected over a wide spectral range. In this paper, we present the results from the experimental investigation and theoretical analysis of large number of holograms of the transmissive and reflective types. We discuss the attained angular and wavelength spectra, bandwidths, wavelength shifts and the diffraction efficiencies as functions of the holographic parameters. The HOEs are made for technical applications and are designed to operate in the 300 nm - 1500 m spectral range.

  18. Petascale cyberinfrastructure for ground-based solar physics: approach of the DKIST data center

    Science.gov (United States)

    Berukoff, S.; Hays, T.; Reardon, K.; Spiess, DJ; Watson, F.; Wiant, S.

    2016-07-01

    The Daniel K Inouye Solar Telescope, under construction in Maui, is designed to perform high-resolution spectropolarimetric visible and infrared measurements of the Sun, and will annually produce 3 PB of data, via 5x108 images and 2x1011 metadata elements requiring calibration, long-term data management, and open and free distribution. After briefly describing the DKIST and its instrument suite, we provide an overview of functions that the DKIST Data Center will provide, and focus on major challenges in its development. We conclude by discussing approach and mention some technologies that the Data Center team is using to develop a petascale computational and data storage resource to support this unique world-class DKIST facility and support its long-term scientific and operational goals.

  19. Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

    Science.gov (United States)

    McKibben, R. B.; Connell, J. J.; Lopate, C.; Zhang, M.; Anglin, J. D.; Balogh, A.; dalla, S.; Sanderson, T. R.; Marsden, R. G.; Hofer, M. Y.; Kunow, H.; Posner, A.; Heber, B.

    2003-06-01

    In 2000-2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum. Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but clear latitude gradients were observed during the similar phase of Ulysses' orbit near the 1994-95 solar minimum. At proton energies above ~10 MeV and extending up to >70 MeV, the intensities are often dominated by Solar Energetic Particles (SEPs) accelerated near the Sun in association with intense solar flares and large Coronal Mass Ejections (CMEs). At lower energies the particle intensities are almost constantly enhanced above background, most likely as a result of a mix of SEPs and particles accelerated by interplanetary shocks. Simultaneous high-latitude Ulysses and near-Earth observations show that most events that produce large flux increases near Earth also produce flux increases at Ulysses, even at the highest latitudes attained. Particle anisotropies during particle onsets at Ulysses are typically directed outwards from the Sun, suggesting either acceleration extending to high latitudes or efficient cross-field propagation somewhere inside the orbit of Ulysses. Both cosmic ray and SEP observations are consistent with highly efficient transport of energetic charged particles between the equatorial and polar regions and across the mean interplanetary magnetic fields in the inner heliosphere.

  20. The flare origin of Forbush decreases not associated with solar flares on the visible hemisphere of the Sun

    Science.gov (United States)

    Iucci, N.; Parisi, M.; Signorini, C.; Storini, M.; Villoresi, G.

    1985-01-01

    Investigations have shown that Forbush decreases (Fds) are produced by the propagation into the interplanetary space of a strong perturbation originating from a solar flare (Sf) accompanied by Type IV radioemission. As the front of the perturbation propagates into the interplanetary space, the region in which the galactic cosmic rays are modulated (Fd-modulated region) rotates westward with the Sun and is generally included between two boundary streams; therefore the Fds not associated with observed type IV Sfs (N.Ass.Fds) are likely to be produced by type IV Sfs occurred on the Sun's backside: these vents can be observed when the Earth crosses the corotating Western boundary of the modulated region.

  1. Comparison of the Changes in the Visible and Infrared Irradiance Observed by the SunPhotometers on EURECA to the UARS Total Solar and UV Irradiances

    Science.gov (United States)

    Pap, Judit

    1995-01-01

    Solar irradiance in the near-UV (335 nm), visible (500 nm) and infrared (778 nm) spectral bands has been measured by the SunPhotometers developed at the World Radiation Center, Davos, Switzerland on board the European Retrievable Carrier between August 1992 and May 1993. Study of the variations in the visible and infrared irradiance is important for both solar and atmospheric physics. The purpose of this paper is to examine the temporal variations observed in the visible and infrared spectral bands after eliminating the trend in the data mainly related to instrument degradation. The effect of active regions in these spectral irradiances is clearly resolved. Variations in the visible and infrared irradiances are compared to total solar irradiance observed by the SOVA2 radiometer on the EURECA platform and by the ACRIMII radiometer on UARS as well as to UV observations of the UARS and NOAA9 satellites. The space-borne spectral irradiance observations are compared to the photometric sunspot deficit and CaII K irradiance measured at the San Fernando Observatory, California State University at Northridge in order to study the effect of active regions in detail.

  2. Comparison of the Changes in the Visible and Infrared Irradiance Observed by the SunPhotometers on EURECA to the UARS Total Solar and UV Irradiances

    Science.gov (United States)

    Pap, Judit

    1995-01-01

    Solar irradiance in the near-UV (335 nm), visible (500 nm) and infrared (778 nm) spectral bands has been measured by the SunPhotometers developed at the World Radiation Center, Davos, Switzerland on board the European Retrievable Carrier between August 1992 and May 1993. Study of the variations in the visible and infrared irradiance is important for both solar and atmospheric physics. The purpose of this paper is to examine the temporal variations observed in the visible and infrared spectral bands after eliminating the trend in the data mainly related to instrument degradation. The effect of active regions in these spectral irradiances is clearly resolved. Variations in the visible and infrared irradiances are compared to total solar irradiance observed by the SOVA2 radiometer on the EURECA platform and by the ACRIMII radiometer on UARS as well as to UV observations of the UARS and NOAA9 satellites. The space-borne spectral irradiance observations are compared to the photometric sunspot deficit and CaII K irradiance measured at the San Fernando Observatory, California State University at Northridge in order to study the effect of active regions in detail.

  3. A Thermodynamic History of the Solar Constitution — II: The Theory of a Gaseous Sun and Jeans' Failed Liquid Alternative

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available In this work, the development of solar theory is followed from the concept that the Sun was an ethereal nuclear body with a partially condensed photosphere to the creation of a fully gaseous object. An overview will be presented of the liquid Sun. A powerful lineage has brought us the gaseous Sun and two of its main authors were the direct sci- entific descendants of Gustav Robert Kirchhoff: Franz Arthur Friedrich Schuster and Arthur Stanley Eddington. It will be discovered that the seminal ideas of Father Secchi and Herv ́ e Faye were not abandoned by astronomy until the beginning of 20th century. The central role of carbon in early solar physics will also be highlighted by revisit- ing George Johnstone Stoney. The evolution of the gaseous models will be outlined, along with the contributions of Johann Karl Friedrich Z ̈ ollner, James Clerk Maxwell, Jonathan Homer Lane, August Ritter, William Thomson, William Huggins, William Edward Wilson, George Francis FitzGerald, Jacob Robert Emden, Frank Washington Very, Karl Schwarzschild, and Edward Arthur Milne. Finally, with the aid of Edward Arthur Milne, the work of James Hopwood Jeans, the last modern advocate of a liquid Sun, will be rediscovered. Jeans was a staunch advocate of the condensed phase, but deprived of a proper building block, he would eventually abandon his non-gaseous stars. For his part, Subrahmanyan Chandrasekhar would spend nine years of his life studying homogeneous liquid masses. These were precisely the kind of objects which Jeans had considered for his liquid stars.

  4. POlarization Emission of Millimeter Activity at the Sun (POEMAS): New Circular Polarization Solar Telescopes at Two Millimeter Wavelength Ranges

    Science.gov (United States)

    Valio, Adriana; Kaufmann, P.; Giménez de Castro, C. G.; Raulin, J.-P.; Fernandes, L. O. T.; Marun, A.

    2013-04-01

    We present a new system of two circular polarization solar radio telescopes, POEMAS, for observations of the Sun at 45 and 90 GHz. The novel characteristic of these instruments is the capability to measure circular right- and left-hand polarizations at these high frequencies. The two frequencies were chosen so as to bridge the gap at radio frequencies between 20 and 200 GHz of solar flare spectra. The telescopes, installed at CASLEO Observatory (Argentina), observe the full disk of the Sun with a half power beam width of 1.4∘, a time resolution of 10 ms at both frequencies, a sensitivity of 2 - 4 K that corresponds to 4 and 20 solar flux unit (=104 Jy), considering aperture efficiencies of 50±5 % and 75±8 % at 45 and 90 GHz, respectively. The telescope system saw first light in November 2011 and is satisfactorily operating daily since then. A few flares were observed and are presented here. The millimeter spectra of some flares are seen to rise toward higher frequencies, indicating the presence of a new spectral component distinct from the microwave one.

  5. solarFLAG hare and hounds: estimation of p-mode frequencies from Sun-as-star helioseismology data

    CERN Document Server

    Jiménez-Reyes, S J; García, R A; Appourchaux, T; Baudin, F; Boumier, P; Elsworth, Y; Fletcher, S T; Lazrek, M; Leibacher, J W; Lochard, J; New, R; Regulo, C; Salabert, D; Toutain, T; Verner, G A; Wachter, R

    2008-01-01

    We report on the results of the latest solarFLAG hare-and-hounds exercise, which was concerned with testing methods for extraction of frequencies of low-degree solar p modes from data collected by Sun-as-a-star observations. We have used the new solarFLAG simulator, which includes the effects of correlated mode excitation and correlations with background noise, to make artificial timeseries data that mimic Doppler velocity observations of the Sun as a star. The correlations give rise to asymmetry of mode peaks in the frequency power spectrum. Ten members of the group (the hounds) applied their ``peak bagging'' codes to a 3456-day dataset, and the estimated mode frequencies were returned to the hare (who was WJC) for comparison. Analysis of the results reveals a systematic bias in the estimated frequencies of modes above approximately 1.8 mHz. The bias is negative, meaning the estimated frequencies systematically underestimate the input frequencies. We identify two sources that are the dominant contributions t...

  6. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere IV. On the Nature of the Chromosphere

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available The chromosphere is the site of weak emission lines characterizing the flash spectrum observed for a few seconds during a total eclipse. This layer of the solar atmosphere is known to possess an opaque Hα emission and a great number of spicules, which can extend well above the photosphere. A stunning variety of hydrogen emission lines have been observed in this region. The production of these lines has provided the seventeenth line of evidence that the Sun is comprised of condensed matter (Robitaille P.M. Liquid Metallic Hydrogen II: A critical assessment of current and primordial helium levels in Sun. Progr. Phys., 2013, v. 2, 35–47. Contrary to the gaseous solar models, the simplest mechanism for the production of emission lines is the evaporation of excited atoms from condensed surfaces existing within the chromosphere, as found in spicules. This is reminiscent of the chemiluminescence which occurs during the condensation of silver clusters (Konig L., Rabin I., Schultze W., and Ertl G. Chemiluminescence in the Agglomeration of Metal Clusters. Science, v. 274, no. 5291, 1353–1355. The process associated with spicule formation is an exothermic one, requiring the transport of energy away from the site of condensation. As atoms leave localized surfaces, their electrons can occupy any energy level and, hence, a wide variety of emission lines are produced. In this regard, it is hypothesized that the presence of hydrides on the Sun can also facilitate hydrogen condensation in the chromosphere. The associated line emission from main group and transition elements constitutes the thirtieth line of evidence that the Sun is condensed matter. Condensation processes also help to explain why spicules manifest an apparently constant temperature over their entire length. Since the corona supports magnetic field lines, the random orientations associated with spicule formation suggests that the hydrogen condensates in the chromosphere are not metallic in

  7. Using the EUV to Weigh a Sun-Grazing Comet as it Disappears in the Solar Corona

    Science.gov (United States)

    Pesnell, William Dean; Schrijiver, Carolus J.; Brown, John C.; Battams, Karl; Saint-Hilaire, Pascal; Hudson Hugh S.; Lui, Wei

    2012-01-01

    On July 6,2011, the Atmospheric Imaging Assembly (AlA) on the Solar Dynamics Observatory (SDO) observed a comet in most of its EUY passbands. The comet disappeared while moving through the solar corona. The comet penetrated to 0.146 solar radii ($\\simapprox.100,000 km) above the photosphere before its EUY faded. Before then, the comet's coma and a tail were observed in absorption and emission, respectively. The material in the variable tail quickly fell behind the nucleus. An estimate of the comet's mass based on this effect, one derived from insolation, and one using the tail's EUY brightness, all yield $\\sim 50$ giga-grams some 10 minutes prior to the end of its visibility. These unique first observations herald a new era in the study of Sun-grazing comets close to their perihelia and of the conditions in the solar corona and solar wind. We will discuss the observations and interpretation of the comet by SDO as well as the coronagraph observations from SOHO and STEREO. A search of the SOHO comet archive for other comets that could be observed in the SDO; AlA EUY channels will be described

  8. Little Sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  9. Little sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  10. The Sun

    CERN Document Server

    Golub, Leon

    2017-01-01

    Essential for life on earth and a major influence on our environment, the Sun is also the most fascinating object in the daytime sky. Every day we feel the effect of its coming and going – literally the difference between day and night. But figuring out what the Sun is, what it’s made of, why it glows so brightly, how old it is, how long it will last – all of these take thought and observation. Leon Golub and Jay M. Pasachoff offer an engaging and informative account of what scientists know about the Sun, and the history of these discoveries. Solar astronomers have studied the Sun over the centuries both for its intrinsic interest and in order to use it as a laboratory to reveal the secrets of other stars. The authors discuss the surface of the Sun, including sunspots and their eleven-year cycle, as well as the magnetism that causes them; the Sun’s insides, as studied mainly from seismic waves that astronomers record on its surface; the outer layers of the Sun that we see from Earth only at eclipses ...

  11. Solar Thermal Propulsion Improvements at Marshall Space Flight Center

    Science.gov (United States)

    Gerrish, Harold P.

    2003-01-01

    Solar Thermal Propulsion (STP) is a concept which operates by transferring solar energy to a propellant, which thermally expands through a nozzle. The specific impulse performance is about twice that of chemical combustions engines, since there is no need for an oxidizer. In orbit, an inflatable concentrator mirror captures sunlight and focuses it inside an engine absorber cavity/heat exchanger, which then heats the propellant. The primary application of STP is with upperstages taking payloads from low earth orbit to geosynchronous earth orbit or earth escape velocities. STP engines are made of high temperature materials since heat exchanger operation requires temperatures greater than 2500K. Refractory metals such as tungsten and rhenium have been examined. The materials must also be compatible with hot hydrogen propellant. MSFC has three different engine designs, made of different refractory metal materials ready to test. Future engines will be made of high temperature carbide materials, which can withstand temperatures greater than 3000K, hot hydrogen, and provide higher performance. A specific impulse greater than 1000 seconds greatly reduces the amount of required propellant. A special 1 OkW solar ground test facility was made at MSFC to test various STP engine designs. The heliostat mirror, with dual-axis gear drive, tracks and reflects sunlight to the 18 ft. diameter concentrator mirror. The concentrator then focuses sunlight through a vacuum chamber window to a small focal point inside the STP engine. The facility closely simulates how the STP engine would function in orbit. The flux intensity at the focal point is equivalent to the intensity at a distance of 7 solar radii from the sun.

  12. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere VI. Helium in the Chromosphere

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available Molecular hydrogen and hydrides have recently been advanced as vital agents in the generation of emission spectra in the chromosphere. This is a result of the role they play in the formation of condensed hydrogen structures (CHS within the chromosphere (P.M. Robitaille. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere IV. On the Nature of the Chromosphere. Progr. Phys., 2013, v. 3, 15–21. Next to hydrogen, helium is perhaps the most intriguing component in this region of the Sun. Much like other elements, which combine with hydrogen to produce hydrides, helium can form the well-known helium hydride molecular ion, HeH+, and the excited neutral helium hydride molecule, HeH∗. While HeH+ is hypothesized to be a key cosmologicalmolecule, its possible presence in the Sun, and that of its excited neutral counterpart, has not been considered. Still, these hydrides are likely to play a role in the synthesis of CHS, as the He I and He II emission lines strongly suggest. In this regard, the study of helium emission spectra can provide insight into the condensed nature of the Sun, especially when considering the 10830 Å line associated with the 23P→2 3S triplet state transition. This line is strong in solar prominences and can be seen clearly on the disk. The excessive population of helium triplet states cannot be adequately explained using the gaseous models, since these states should be depopulated by collisional processes. Conversely, when He-based molecules are used to build CHS in a liquid metallic hydrogen model, an ever increasing population of the 23S and 23P states might be expected. The overpopulation of these triplet states leads to the conclusion that these emission lines are unlikely to be produced through random collisional or photon excitation, as required by the gaseous models. This provides a significant hurdle for these models. Thus, the strong 23P→2 3S lines and the overpopulation of the helium triplet

  13. Solar energy facility at North Hampton Recreation Center, Dallas, Texas

    Science.gov (United States)

    1980-01-01

    The solar energy facility located at the North Hampton Park Recreation and Health Center, Dallas, Texas is presented. The solar energy system is installed in a single story (two heights), 16,000 sq ft building enclosing a gymnasium, locker area, and health care clinic surrounded by a recreational area and athletic field. The solar energy system is designed to provide 80 percent of the annual space heating, 48 percent of the annual space cooling, and 90 percent of the domestic hot water requirements. The system's operation modes and performance data acquisition system are described. The system's performance during the months of June, July, August, September, and October of 1979 are presented and show a negative savings of energy. Experience to date indicates however that the system concept has promise of acceptable performance. It is concluded that if proper control and sequencing components was maintained, then the system performance would improve to an acceptable level.

  14. Radioactive Probes of the Supernova-Contaminated Solar Nebula: Evidence that the Sun was Born in a Cluster

    CERN Document Server

    Looney, L W; Fields, B D; Looney, Leslie W.; Tobin, John J.; Fields, Brian D.

    2006-01-01

    We construct a simple model for radioisotopic enrichment of the protosolar nebula by injection from a nearby supernova, based on the inverse square law for ejecta dispersion. We find that the presolar radioisotopes abundances (i.e., in solar masses) demand a nearby supernova: its distance can be no larger than 66 times the size of the protosolar nebula, at a 90% confidence level, assuming 1 solar mass of protosolar material. The relevant size of the nebula depends on its state of evolution at the time of radioactivity injection. In one scenario, a collection of low-mass stars, including our sun, formed in a group or cluster with an intermediate- to high-mass star that ended its life as a supernova while our sun was still a protostar, a starless core, or perhaps a diffuse cloud. Using recent observations of protostars to estimate the size of the protosolar nebula constrains the distance of the supernova at 0.02 to 1.6 pc. The supernova distance limit is consistent with the scales of low-mass stars formation ar...

  15. Release History and Transport Parameters of Relativistic Solar Electrons Inferred From Near-the-Sun In Situ Observations

    Science.gov (United States)

    Agueda, N.; Lario, D.

    2016-10-01

    We study four consecutive 300-800 keV electron events observed on 1980 May 28 by Helios-1, when the spacecraft was located at 0.31 au from the Sun. We use two different techniques to extract the release time history of electrons at the Sun: (1) a data-driven method based on the assumption that particles conserve their magnetic moment as they propagate between the Sun and the spacecraft and (2) an inversion method that utilizes particle transport simulation results. Both methods make use of the particle angular distributions measured relative to the local direction of the magnetic field. The general characteristics of the release time profiles obtained by these two techniques are similar, especially during their rising phases. We find indications that the strength of the interplanetary scattering varies with the size of the solar parent event, suggesting that scattering processes are not necessarily an inherent property of the medium but are related to the amount of released particles at the Sun. We use the inferred release profiles to compute the expected intensities at 1 au. In contrast to simultaneous near-Earth observations by the Interplanetary Monitoring Platform (IMP-8), our simulations predict the observation of four separate events at 1 au. Processes that could contribute to the observation of one single time-extended event at 1 au include (1) distinct magnetic connections of the spacecraft to the particle sources, (2) the spatio-temporal evolution of the particle sources, and (3) different particle transport conditions, including a variation of {λ }r with radial distance and/or heliolongitude, as well as the possibility that electrons reached IMP-8 by diffusion perpendicular to the interplanetary magnetic field.

  16. Sun Proof

    Centers for Disease Control (CDC) Podcasts

    2012-10-23

    In this podcast for kids, the Kidtastics talk about the harmful effects of the sun and how to protect yourself from it.  Created: 10/23/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/23/2012.

  17. Long-term field test of solar PV power generation using one-axis 3-position sun tracker

    KAUST Repository

    Huang, B.J.

    2011-09-01

    The 1 axis-3 position (1A-3P) sun tracking PV was built and tested to measure the daily and long-term power generation of the solar PV system. A comparative test using a fixed PV and a 1A-3P tracking PV was carried out with two identical stand-alone solar-powered LED lighting systems. The field test in the particular days shows that the 1A-3P tracking PV can generate 35.8% more electricity than the fixed PV in a partly-cloudy weather with daily-total solar irradiation HT=11.7MJ/m2day, or 35.6% in clear weather with HT=18.5MJ/m2day. This indicates that the present 1A-3P tracking PV can perform very close to a dual-axis continuous tracking PV (Kacira et al., 2004). The long-term outdoor test results have shown that the increase of daily power generation of 1A-3P tracking PV increases with increasing daily-total solar irradiation. The increase of monthly-total power generation for 1A-3P sun tracking PV is between 18.5-28.0%. The total power generation increase in the test period from March 1, 2010 to March 31, 2011, is 23.6% in Taipei (an area of low solar energy resource). The long-term performance of the present 1X-3P tracking PV is shown very close to the 1-axis continuous tracking PV in Taiwan (Chang, 2009). If the 1A-3P tracking PV is used in the area of high solar energy resource with yearly-average HT>17MJ/m2day, the increase of total long-term power generation with respect to fixed PV will be higher than 37.5%. This is very close to that of dual-axis continuous tracking PV. The 1A-3P tracker can be easily mounted on the wall of a building. The cost of the whole tracker is about the same as the regular mounting cost of a conventional rooftop PV system. This means that there is no extra cost for 1A-3P PV mounted on buildings. The 1A-3P PV is quite suitable for building-integrated applications. © 2011 Elsevier Ltd.

  18. Coupling of the Matched Gravity and Electromagnetic Fields of the Sun with Jupiter and its Moons Together in Nearest Portion of Jupiter's Orbit to the Sun as the Main Cause of the Peak of Approximately 11 Yearly Solar Cycles and Hazards from Solar Storms

    Science.gov (United States)

    Gholibeigian, Kazem; Gholibeigian, Hassan

    2016-04-01

    On March 13, 1989 the entire province of Quebec Blackout by solar storm during solar cycle 22. The solar storm of 1859, also known as the Carrington event, was a powerful geomagnetic solar storm during solar cycle 10. The solar storm of 2012 during solar cycle 24 was of similar magnitude, but it passed Earth's orbit without striking the plane. All of these solar storms occurred in the peak of 11 yearly solar cycles. In this way, the White House in its project which is focusing on hazards from solar system, in a new strategy and action plan to increase protection from damaging solar emissions, should focus on coupling of the matched Gravity and Electromagnetic Fields)GEFs) of the Sun with Jupiter and its moons together. On the other hand, in solar system, the Jupiter's gravity has largest effect to the Sun's core and its dislocation, because the gravity force between the Jupiter and the Sun is 11.834 times, In addition overlapping of the solar cycles with the Jupiter's orbit period is 11.856 years. These observable factors lead us to the effect of the Jupiter and Sun gravity fields coupling as the main cause of the approximately 11 years duration for solar cycles. Its peak in each cycle is when the Jupiter is in nearest portion to the Sun in its orbit. In this way, the other planets in their coupling with Sun help to the variations and strengthening solar cycles. [Gholibeigian, 7/24/2015http://adsabs.harvard.edu/abs/2014EGU]. In other words, the both matched GEFs are generating by the large scale forced convection system inside the stars and planets [Gholibeigian et. al, AGU Fall Meeting 2015]. These two fields are couple and strengthening each other. The Jupiter with its 67 moons generate the largest coupled and matched GEFs in its core and consequently strongest effect on the Sun's core. Generation and coupling of the Jupiter's GEFs with its moons like Europa, Io and Ganymede make this planet of thousands of times brighter and many times bigger than Earth as the

  19. The vectorial photoelectric effect under solar irradiance and its application to sun sensing

    CERN Document Server

    Hechenblaikner, Gerald

    2014-01-01

    Sun sensors are an integral part of the attitude and orbit control system onboard almost any spacecraft. While the majority of standard analogue sun sensors is based on photo-detectors which produce photo-currents proportional to the cosine of the incidence angle (cosine detectors), we propose an alternative scheme where the vectorial photoelectric effect is exploited to achieve a higher sensitivity of the sensed photo-current to the incidence angle. The vectorial photo-effect is investigated in detail for metal cathode detectors in a space environment. Besides long operational lifetimes without significant degradation, metal cathode detectors are insensitive to earth albedo, which may significantly reduce the errors affecting attitude measurements in low earth orbits. Sensitivity curves are calculated and trade-offs performed with the aim of optimizing the sensitivity whilst also providing currents sufficient for detection. Simple applications and detector configurations are also discussed and compared to ex...

  20. The sun emulator: A means for achieving the widespread acceptance of solar responsive design

    Energy Technology Data Exchange (ETDEWEB)

    Lechner, N.M. [Auburn University College of Architecture, Design, and Construction, AL (United States)

    2004-07-01

    It is hard to believe that a rather simple mechanical device could be a such a powerful teaching and design tool. It is also hard to believe that such a device could have a major impact on our energy future, the environment, and especially global warming. My 27 year teaching experience with heliodons makes me believe that ''conceptually clear'' heliodons truly are powerful teaching tools that can greatly convince and motivate people. Also since they never wear out and will never become obsolete, they are a good investment for creating a better future. More information about the Sun Emulator is available from my Auburn University website: www.cadc.auburn.edu/sun-emulator and the manufacturer's website: www.hpd-online.com (orig.)

  1. Solar heating and cooling demonstration project at the Florida Solar Energy Center

    Energy Technology Data Exchange (ETDEWEB)

    Hankins, J.D.

    1980-02-01

    The retrofitted solar heating and cooling system installed at the Florida Solar Energy Center is described. Information is provided on the system's test, operation, controls, hardware and installation, including detailed drawings. The Center's office building, approximately 5000 square feet of space, with solar air conditioning and heating as a demonstration of the technical feasibility is located just north of Port Canaveral, Florida. The system was designed to supply approximately 70% of the annual cooling and 100% of the heating load. The project provides unique high-temperature, non-imaging, non-tracking, evacuated-tube collectors. The design of the system was kept simple and employs five hydronic loops. They are energy collection, chilled water production, space cooling, space heating and energy rejection.

  2. The Solar System is According to General Relativity: The Sun's Space Breaking Meets the Asteroid Strip

    Directory of Open Access Journals (Sweden)

    Borissova L.

    2010-04-01

    Full Text Available This study deals with the exact solution of Einstein's field equations for a sphere of incompressible liquid without the additional limitation initially introduced in 1916 by Schwarzschild, by which the space-time metric must have no singularities. The obtained exact solution is then applied to the Universe, the Sun, and the planets, by the assumption that these objects can be approximated as spheres of incompressible liquid. It is shown that gravitational collapse of such a sphere is permitted for an object whose characteristics (mass, density, and size are close to the Universe. Meanwhile, there is a spatial break associated with any of the mentioned stellar objects: the~break is determined as the approaching to infinity of one of the spatial components of the metric tensor. In particular, the break of the Sun's space meets the Asteroid strip, while Jupiter's space break meets the Asteroid strip from the outer side. Also, the space breaks of Mercury, Venus, Earth, and Mars are located inside the Asteroid strip (inside the Sun's space break.

  3. Statistical characterization of Strong and Mid Solar Flares and Sun EUV rate monitoring with GNSS

    Science.gov (United States)

    Monte-Moreno, Enric; Hernandez-Pajares, Manuel; Garcia-Rigo, Alberto; Beniguel, Yannick; Orus-Perez, Raul; Prieto-Cerdeira, Roberto; Schlueter, Stefan

    2015-04-01

    The global network of permanent Global Navigation Satellite Systems (GNSS) receivers has become an useful and affordable way of monitoring the Solar EUV flux rate, especially -for the time being- in the context of Major and Mid geoeffective intensity Solar Flares (M. Hernandez-Pajares et al., Space Weather, doi:10.1029/2012SW000826, 2012). In fact the maturity of this technique (GNSS Solar FLAre Indicator, GSFLAI) has allowed to incorporate it in operational real-time (RT) conditions, thanks to the availability of global GNSS datastreams from the RT International GNSS Network (M. Caissy et al, GPS World, June 1, 2012), and performed in the context of the MONITOR and MONITOR2 ESA-funded projects (Y. Beniguel et al., NAVITEC Proc., 978-1-4673-2011-5 IEEE, 2012). The main goal of this presentation is to summarize a detailed recent study of the statistical properties of Solar Flares (E. Monte and M. Hernandez-Pajares, J. Geophys. Res., doi:10.1002/2014JA020206, 2014) by considering the GNSS proxy of EUV rate (GSFLAI parameter) computed independently each 30 seconds during the whole last solar cycle. An statistical model has been characterized that explains the empirical results such as (a) the persistence and presence of bursts of solar flares and (b) their long tail peak values of the solar flux variation, which can be characterized by: (1) A fractional Brownian model for the long-term dependence, and (2), a power law distribution for the time series extreme values. Finally, an update of the Solar Flares' occurrence during the recent months of Solar Activity, gathered in RT within MONITOR2 project, will close the paper.

  4. The achievements of solar children from the natural created octave whose source is the emanating sun reflected by the Foundation for Solar Achievement with the Arts

    Energy Technology Data Exchange (ETDEWEB)

    Petacchi, D.V. [Foundation for Solar Achievement with the Arts, Hobart, NY (United States)

    1997-12-31

    The Foundation for Solar Achievement With The Arts is a not-for-profit school training gifted children in the use of their talent in accordance with the philosophy and experience that children in harmony with their natural environment based upon the sun`s position in the course of the day have the greater capacity of attention necessary to enhance learning and creativity. Uncluttered as much as possible by the distractions of technology or the artificial glare of electricity, the learning environment of the Foundation for Solar Achievement With The Arts is conducive to this hands-on action. The Foundation was started by an individual whose life long search for the meaning of his life and whose pondering on the meaning human life on this planet led him to many conclusions modern science is just beginning to reach. With the help of dedicated architect John Jehring and likeminded others, Mr. Petacchi is utilizing natural sunlight in an environment conducive to the psyche of children. A building is planned that will expand into indoor form the natural lighting and free space of the out-of-doors.

  5. The Sun and Earth

    Science.gov (United States)

    Gopalswamy, Natchimuthuk

    2012-01-01

    Thus the Sun forms the basis for life on Earth via the black body radiation it emits. The Sun also emits mass in the form of the solar wind and the coronal mass ejections (CMEs). Mass emission also occurs in the form of solar energetic particles (SEPs), which happens during CMEs and solar flares. Both the mass and electromagnetic energy output of the Sun vary over a wide range of time scales, thus introducing disturbances on the space environment that extends from the Sun through the entire heliosphere including the magnetospheres and ionospheres of planets and moons of the solar system. Although our habitat is located in the neutral atmosphere of Earth, we are intimately connected to the non-neutral space environment starting from the ionosphere to the magnetosphere and to the vast interplanetary space. The variability of the solar mass emissions results in the interaction between the solar wind plasma and the magnetospheric plasma leading to huge disturbances in the geospace. The Sun ionizes our atmosphere and creates the ionosphere. The ionosphere can be severely disturbed by the transient energy input from solar flares and the solar wind during geomagnetic storms. The complex interplay between Earth's magnetic field and the solar magnetic field carried by the solar wind presents varying conditions that are both beneficial and hazardous to life on earth. This seminar presents some of the key aspects of this Sun-Earth connection that we have learned since the birth of space science as a scientific discipline some half a century ago.

  6. Letting the Sun Shine on Solar Costs: An Empirical Investigation of Photovoltaic Cost Trends in California

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, R.; Bolinger, M.; Cappers, P.; Margolis, R.

    2006-01-01

    This report provides a comprehensive analysis of grid-connected solar photovoltaic (PV) cost trends in California, which is by far the largest PV market in the United States. The findings of this work may help stakeholders to understand important trends in the California PV market, and policymakers to design more effective solar incentive programs--a particularly important objective given the recent announcement from the California Public Utilities Commission (CPUC) to establish an 11-year, $3.2 billion incentive program for customer-sited solar. The study statistically analyzes the installed cost of grid-connected PV systems funded by the state's two largest solar rebate programs, overseen by the California Energy Commission (CEC) [operating since 1998] and the CPUC [operating since 2001].

  7. Letting the Sun Shine on Solar Costs: An Empirical Investigation of Photovoltaic Cost Trends in California

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, R.; Bolinger, M.; Cappers, P.; Margolis, R.

    2006-01-01

    This report provides a comprehensive analysis of grid-connected solar photovoltaic (PV) cost trends in California, which is by far the largest PV market in the United States. The findings of this work may help stakeholders to understand important trends in the California PV market, and policymakers to design more effective solar incentive programs--a particularly important objective given the recent announcement from the California Public Utilities Commission (CPUC) to establish an 11-year, $3.2 billion incentive program for customer-sited solar. The study statistically analyzes the installed cost of grid-connected PV systems funded by the state's two largest solar rebate programs, overseen by the California Energy Commission (CEC) [operating since 1998] and the CPUC [operating since 2001].

  8. The acoustic cut-off frequency of the Sun and the solar magnetic activity cycle

    CERN Document Server

    Jimenez, A; Palle, P L

    2011-01-01

    The acoustic cut-off frequency -the highest frequency for acoustic solar eigenmodes- is an important parameter of the solar atmosphere as it determines the upper boundary of the p-mode resonant cavities. At frequencies beyond this value, acoustic disturbances are no longer trapped but traveling waves. Interference amongst them give rise to higher-frequency peaks -the pseudomodes- in the solar acoustic spectrum. The pseudomodes are shifted slightly in frequency with respect to p modes making possible the use of pseudomodes to determine the acoustic cut-off frequency. Using data from GOLF and VIRGO instruments on board the SOHO spacecraft, we calculate the acoustic cut-off frequency using the coherence function between both the velocity and intensity sets of data. By using data gathered by these instruments during the entire lifetime of the mission (1996 till the present), a variation in the acoustic cut-off frequency with the solar magnetic activity cycle is found.

  9. CORONAL HEATING BY THE INTERACTION BETWEEN EMERGING ACTIVE REGIONS AND THE QUIET SUN OBSERVED BY THE SOLAR DYNAMICS OBSERVATORY

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jun; Zhang, Bin; Li, Ting; Yang, Shuhong; Zhang, Yuzong; Li, Leping [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Chen, Feng; Peter, Hardi, E-mail: zjun@nao.cas.cn, E-mail: liting@nao.cas.cn, E-mail: shuhongyang@nao.cas.cn, E-mail: yuzong@nao.cas.cn, E-mail: lepingli@nao.cas.cn, E-mail: chen@mps.mpg.de, E-mail: peter@mps.mpg.de [Max-Planck Institute for Solar System Research (MPS), D-37077, Göttingen (Germany)

    2015-02-01

    The question of what heats the solar corona remains one of the most important puzzles in solar physics and astrophysics. Here we report Solar Dynamics Observatory Atmospheric Imaging Assembly observations of coronal heating by the interaction between emerging active regions (EARs) and the surrounding quiet Sun (QS). The EARs continuously interact with the surrounding QS, resulting in dark ribbons which appear at the boundary of the EARs and the QS. The dark ribbons visible in extreme-ultraviolet wavelengths propagate away from the EARs with speeds of a few km s{sup −1}. The regions swept by the dark ribbons are brightening afterward, with the mean temperature increasing by one quarter. The observational findings demonstrate that uninterrupted magnetic reconnection between EARs and the QS occurs. When the EARs develop, the reconnection continues. The dark ribbons may be the track of the interface between the reconnected magnetic fields and the undisturbed QS’s fields. The propagating speed of the dark ribbons reflects the reconnection rate and is consistent with our numerical simulation. A long-term coronal heating which occurs in turn from nearby the EARs to far away from the EARs is proposed.

  10. Can the Solar Wind be Driven by Magnetic Reconnection in the Sun's Magnetic Carpet?

    OpenAIRE

    Cranmer, Steven R.; van Ballegooijen, Adriaan A.

    2010-01-01

    The physical processes that heat the solar corona and accelerate the solar wind remain unknown after many years of study. Some have suggested that the wind is driven by waves and turbulence in open magnetic flux tubes, and others have suggested that plasma is injected into the open tubes by magnetic reconnection with closed loops. In order to test the latter idea, we developed Monte Carlo simulations of the photospheric "magnetic carpet" and extrapolated the time-varying coronal field. These ...

  11. The State of Self-Organized Criticality of the Sun During the Last 3 Solar Cycles

    CERN Document Server

    Aschwanden, Markus J

    2010-01-01

    We analyze the occurrence frequency distributions of peak fluxes $P$, total fluxes $E$, and durations $T$ of solar flares over the last three solar cycles (during 1980-2010) from hard X-ray data of HXRBS/SMM, BATSE/CGRO, and RHESSI. From the synthesized data we find powerlaw slopes with mean values of $\\alpha_P=1.75\\pm0.05$ for the peak flux, $\\alpha_E=1.61\\pm0.04$ for the total flux, and $\\alpha_T=2.08\\pm0.10$ for flare durations. We find no evidence that these frequency distributions have significantly different slopes during the minima of the solar cycles, including the current anomalously extended solar minimum. The powerlaw distributions can be interpreted in terms of a nonlinear dissipative system in the state of self-organized criticality (SOC). The invariance of the powerlaw slopes during the solar cycles, despite of the nonstationarity of the flare rate by orders of magnitude, implies a universal behavior in the nonlinear growth evolution of magnetic instabilities in solar flares, independent of a sl...

  12. On the Path to SunShot. The Environmental and Public Health Benefits of Achieving High Solar Penetrations in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mai, Trieu [National Renewable Energy Lab. (NREL), Golden, CO (United States); Millstein, Dev [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Carpenter, Alberta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cohen, Stuart [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cole, Wesley [National Renewable Energy Lab. (NREL), Golden, CO (United States); Frew, Bethany [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heath, Garvin [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Compared with fossil fuel generators, photovoltaics (PV) and concentrating solar power (CSP) produce far lower lifecycle levels of greenhouse gas (GHG) emissions and harmful pollutants including fine particular matter (PM2.5), sulfur dioxide (SO2), and nitrogen oxides (NOx). In this report, we monetize the emission reductions from achieving the U.S. Department of Energy's SunShot deployment goals: 14% of U.S. electricity demand met by solar in 2030 and 27% in 2050. We estimate that achieving these goals could reduce cumulative power-sector GHG emissions by 10% between 2015 and 2050, resulting in savings of $238-$252 billion. This is equivalent to 2.0-2.2 cents per kilowatt-hour of solar installed (cents/kWh-solar). Similarly, realizing these levels of solar deployment could reduce cumulative power-sector emissions of PM2.5 by 8%, SO2 by 9%, and NOx by 11% between 2015 and 2050. This could produce $167 billion in savings from lower future health and environmental damages, or 1.4 cents/kWh-solar--while also preventing 25,000-59,000 premature deaths. To put this in perspective, this estimated combined benefit of 3.5 cents/kWh-solar due to SunShot-level solar deployment is approximately equal to the additional levelized cost of electricity reduction needed to make unsubsidized utility-scale solar competitive with conventional generators today. In addition, the analysis shows that achieving the SunShot goals could save 4% of total power-sector water withdrawals and 9% of total power-sector water consumption over the 2015-2050 period--a particularly important consideration for arid states where substantial solar will be deployed. These results have potential implications for policy innovation and the economic competitiveness of solar and other generation technologies.

  13. [Multifocal electroretinogram for assessing sun damage following the solar eclipse of 11 August 1999].

    Science.gov (United States)

    Mack, G; Uzel, J L; Sahel, J; Flament, J

    2002-04-01

    Following the eclipse of 11 August 1999, the ophthalmological clinic of Strasbourg cared for 4 patients who suffered from sun damage. The multifocal electroretinogram (ERG) carried out on our first patient enabled us to not only confirm the existence of a residual maculopathy as shown by the static visual field, but also, and above all to quantify the foveolar deficit. Moreover, with the other 3 patients, the multifocal ERG enabled us to detect a foveolar deficit completely overlooked by the other usual tests. In light of our clinical study, we can assert that the multifocal ERG has yet to be equaled by any other test for analysis of macular function.

  14. Alterations in fruit and vegetable β-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers

    OpenAIRE

    Ndawula, J; Kabasa, JD; Byaruhanga, YB

    2004-01-01

    This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometery at 450nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of vari...

  15. Solar heating and cooling demonstration project at the Florida solar energy center

    Science.gov (United States)

    1980-01-01

    The retrofitted solar heating and cooling system installed at the Florida Solar Energy Center is described. The system was designed to supply approximately 70 percent of the annual cooling and 100 percent of the heating load. The project provides unique high temperature, nonimaging, nontracking, evacuated tube collectors. The design of the system was kept simple and employs five hydronic loops. They are energy collection, chilled water production, space cooling, space heating and energy rejection. Information is provided on the system's acceptance test results operation, controls, hardware and installation, including detailed drawings.

  16. The Sun among stars. IV - Albedos of Uranus and Neptune and the solar color

    Science.gov (United States)

    Hardorp, J.

    1981-01-01

    Geometric albedos in 48 adjacent 50 A bands from 3250 to 5600 A have been derived from observations of Uranus and Neptune. The solar analog found in earlier papers (Hardorp 1978, 1980) was chosen for these reductions, so these albedos are more reliable systematically than earlier ones and allow a choice among the scattering models of Savage et al. (1980). Green methane bands are stronger on Neptune. Strong solar absorption lines are found to be partially filled in by Raman-scattering. Neglect of this effect caused Croft et al. (1972) to find a solar color that is too blue. It probably also affected the classification of G-type stars in the Michigan Spectral Catalogue as well as Garrison's (1979) interpretation of IUE observations.

  17. Here comes the sun...; Here comes the sun...

    Energy Technology Data Exchange (ETDEWEB)

    Best, Robert [Centro de Investigacion en Energia (CIE) de la UNAM, Temixco, Morelos (Mexico)

    2010-07-01

    It sounds a bit strange that you can use solar energy to maintain or refrigerate products or spaces below the ambient temperature, because we know that something that makes the sun is heating; but yes indeed, the sun can produce cold, and in addition without polluting, and without consuming conventional energy. In this document are mentioned the various research projects on solar cooling that have been made in the Energy Research Center at the Universidad Nacional Autonoma de Mexico such as the thermo-chemical intermittent refrigerator, the geothermal cooling demonstration system in Mexicali, B.C., the GAX system for air conditioning, the ice producer intermittent solar refrigerator, the continuous solar refrigerator, the refrigeration by ejection-compression. It also mentions the functioning of heat pumps and the process of solar drying applications in agricultural products. [Spanish] Suena un poco extrano que se pueda utilizar la energia solar para mantener o refrigerar productos o espacios por debajo de la temperatura ambiente, ya que sabemos que algo que hace el sol es calentar; pero si, el sol puede producir frio, y ademas sin contaminar y sin consumir energia convencional. En este documento se mencionan las diferentes investigaciones sobre refrigeracion solar que se han realizado en el Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico como el refrigerador termoquimico intermitente, el sistema demostrativo de refrigeracion geotermico en Mexicali, B.C., el sistema GAX para aire acondicionado, el refrigerador solar intermitente productor de hielo, el refrigerador continuo solar, la refrigeracion por eyecto-compresion. Tambien se menciona el funcionamiento de las bombas de calor y el proceso de secado solar de aplicacion en productos agropecuarios.

  18. Slow twists of solar magnetic flux tubes and the polar magnetic field of the sun

    Science.gov (United States)

    Hollweg, Joseph V.; Lee, Martin A.

    1989-01-01

    The solar wind model of Weber and Davis (1967) is generalized to compute the heliospheric magnetic field resulting from solar rotation or a steady axisymmetric twist including a geometrical expansion which is more rapid than spherical. The calculated increase in the ratio of the toroidal to poloidal field components with heliocentric radial distance r clarifies an expression derived recently by Jokipii and Kota (1989). Magnetic-field components transverse to r do not in general grow to dominate the radial component at large r. The analysis also yields expressions for the Poynting flux associated with the steady twists.

  19. 78 FR 54669 - Draft Environmental Impact Statement for the Proposed RES Americas Moapa Solar Energy Center...

    Science.gov (United States)

    2013-09-05

    ... Vegas Review Journal and the Moapa Valley Progress and on the following Web site: www.MoapaSolarEnergy... of a solar energy ground lease and agreements entered into by the Tribe with Moapa Solar LLC... caption ``DEIS Comments, Proposed Moapa Solar Energy Center'' on the first page of your written...

  20. The SPICE Spectral Imager on Solar Orbiter: Linking the Sun to the Heliosphere

    Science.gov (United States)

    Fludra, Andrzej; Haberreiter, Margit; Peter, Hardi; Vial, Jean-Claude; Harrison, Richard; Parenti, Susanna; Innes, Davina; Schmutz, Werner; Buchlin, Eric; Chamberlin, Phillip; Thompson, William; Gabriel, Alan; Morris, Nigel; Caldwell, Martin; Auchere, Frederic; Curdt, Werner; Teriaca, Luca; Hassler, Donald M.; DeForest, Craig; Hansteen, Viggo; Carlsson, Mats; Philippon, Anne; Janvier, Miho; Wimmer-Schweingruber, Robert; Griffin, Douglas; Davila, Joseph; Giunta, Alessandra; Waltham, Nick; Eccleston, Paul; Gottwald, Alexander; Klein, Roman; Hanley, John; Walls, Buddy; Howe, Chris; Schuehle, Udo

    2016-07-01

    The SPICE (Spectral Imaging of the Coronal Environment) instrument is one of the key remote sensing instruments onboard the upcoming Solar Orbiter Mission. SPICE has been designed to contribute to the science goals of the mission by investigating the source regions of outflows and ejection processes which link the solar surface and corona to the heliosphere. In particular, SPICE will provide quantitative information on the physical state and composition of the solar atmosphere plasma. For example, SPICE will access relative abundances of ions to study the origin and the spatial/temporal variations of the 'First Ionization Potential effect', which are key signatures to trace the solar wind and plasma ejections paths within the heliosphere. Here we will present the instrument and its performance capability to attain the scientific requirements. We will also discuss how different observation modes can be chosen to obtain the best science results during the different orbits of the mission. To maximize the scientific return of the instrument, the SPICE team is working to optimize the instrument operations, and to facilitate the data access and their exploitation.

  1. Solar Current Output as a Function of Sun Elevation: Students as Toolmakers

    Science.gov (United States)

    Igoe, D. P.; Parisi, A. V.

    2015-01-01

    Solar current is an increasingly important aspect of modern life and will be even more so crucial in the students' future. Encouraging students to be the "toolmakers" allows students to take ownership of scientific investigations, as well as forcing them to refine their research questions and hypothesis, including the design and…

  2. Daniel K. Inouye Solar Telescope: High-resolution observing of the dynamic Sun

    Science.gov (United States)

    Tritschler, A.; Rimmele, T. R.; Berukoff, S.; Casini, R.; Kuhn, J. R.; Lin, H.; Rast, M. P.; McMullin, J. P.; Schmidt, W.; Wöger, F.; DKIST Team

    2016-11-01

    The 4-m aperture Daniel K. Inouye Solar Telescope (DKIST) formerly known as the Advanced Technology Solar Telescope (ATST) is currently under construction on Haleakalā (Maui, Hawai'i) projected to start operations in 2019. At the time of completion, DKIST will be the largest ground-based solar telescope providing unprecedented resolution and photon collecting power. The DKIST will be equipped with a set of first-light facility-class instruments offering unique imaging, spectroscopic and spectropolarimetric observing opportunities covering the visible to infrared wavelength range. This first-light instrumentation suite will include: a Visible Broadband Imager (VBI) for high-spatial and -temporal resolution imaging of the solar atmosphere; a Visible Spectro-Polarimeter (ViSP) for sensitive and accurate multi-line spectropolarimetry; a Fabry-Pérot based Visible Tunable Filter (VTF) for high-spatial resolution spectropolarimetry; a fiber-fed Diffraction-Limited Near Infra-Red Spectro-Polarimeter (DL-NIRSP) for two-dimensional high-spatial resolution spectropolarimetry (simultaneous spatial and spectral information); and a Cryogenic Near Infra-Red Spectro-Polarimeter (Cryo-NIRSP) for coronal magnetic field measurements and on-disk observations of, e.g., the CO lines at 4.7 μm. We will provide an overview of the DKIST's unique capabilities with strong focus on the first-light instrumentation suite, highlight some of the additional properties supporting observations of transient and dynamic solar phenomena, and touch on some operational strategies and the DKIST critical science plan.

  3. Comparison of selected metals content in Cambodian striped snakehead fish (Channa striata) using solar drying system and open sun drying.

    Science.gov (United States)

    Basri, Dayang Fredalina; Abu Bakar, Nur Faizah; Fudholi, Ahmad; Ruslan, Mohd Hafidz; Saroeun, Im

    2015-01-01

    The content of 12 elements in Cambodian dried striped snakehead fish was determined using inductively coupled plasma mass spectrometry. The present study compares the level of the trace toxic metals and nutritional trace elements in the fish processed using solar drying system (SDS) and open sun drying (OSD). The skin of SDS fish has lower level of As, Pb, and Cd compared to the OSD sample. As such, the flesh of the fish accumulated higher amount of toxic metals during OSD compared to SDS. However, arsenic was detected in both samples within the safe limit. The nutritional elements (Fe, Mn, Mg, Se, Mo, Cu, Ni, and Cr) were higher in the skin sample SDS fish compared to OSD fish. These beneficial metals were not accumulated in the flesh sample SDS fish demonstrating lower level compared to drying under conventional system. The reddish coloration of the SDS fish was due to the presence of high Cu content in both the skin and flesh samples which possibly account for no mold formation 5 days after packaging. As conclusion, drying of Cambodian C. striata using solar-assisted system has proven higher content of the nutritious elements compared to using the conventional system despite only slight difference in the toxic metals level between the two systems.

  4. Comparison of Selected Metals Content in Cambodian Striped Snakehead Fish (Channa striata Using Solar Drying System and Open Sun Drying

    Directory of Open Access Journals (Sweden)

    Dayang Fredalina Basri

    2015-01-01

    Full Text Available The content of 12 elements in Cambodian dried striped snakehead fish was determined using inductively coupled plasma mass spectrometry. The present study compares the level of the trace toxic metals and nutritional trace elements in the fish processed using solar drying system (SDS and open sun drying (OSD. The skin of SDS fish has lower level of As, Pb, and Cd compared to the OSD sample. As such, the flesh of the fish accumulated higher amount of toxic metals during OSD compared to SDS. However, arsenic was detected in both samples within the safe limit. The nutritional elements (Fe, Mn, Mg, Se, Mo, Cu, Ni, and Cr were higher in the skin sample SDS fish compared to OSD fish. These beneficial metals were not accumulated in the flesh sample SDS fish demonstrating lower level compared to drying under conventional system. The reddish coloration of the SDS fish was due to the presence of high Cu content in both the skin and flesh samples which possibly account for no mold formation 5 days after packaging. As conclusion, drying of Cambodian C. striata using solar-assisted system has proven higher content of the nutritious elements compared to using the conventional system despite only slight difference in the toxic metals level between the two systems.

  5. Multifocal electroretinogram for assessing sun damage following the solar eclipse of 29 March 2006: multifocal electroretinography in solar maculopathy.

    Science.gov (United States)

    Arda, Hatice; Oner, Ayse; Mutlu, Sait; Köse, Ziya; Gumus, Koray; Karakucuk, Sarper; Mirza, Ertugrul

    2007-05-01

    To evaluate the clinical findings and multifocal electroretinography results of cases with solar maculopathy due to eclipse watching. Eight eyes of six patients (ages ranged 12-42) who presented to our clinic after the solar eclipse of 29 March 2006 were evaluated in the study. All patients underwent a full ophthalmologic examination and multifocal electroretinography (mfERG). Visual acuities at the initial examination were between 20/32 and 20/20; and at final examination between 20/25 and 20/20 respectively. Fundoscopic examination disclosed macular pigmentary changes in almost all patients. Fundus Fluorescein Angiography revealed a window defect in six eyes. The initial findings of the mfERG at the first visit showed a decrease in the P1 and N1 amplitudes of the central responses. The following mfERG recordings showed a recovery in central P1 and N1 amplitudes. Decrease in P1 and N1 amplitudes of central macular region can be detected by mfERG in patients with solar maculopathy. Follow-up mfERG test results may recover with the increase of visual acuity.

  6. Energetic Phenomena on the Sun: The Solar Maximum Mission Flare Workshop. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, M.; Woodgate, B.

    1986-12-01

    The general objectives of the conference were as follows: (1) Synthesize flare studies after three years of Solar Maximum Mission (SSM) data analysis. Encourage a broader participation in the SMM data analysis and combine this more fully with theory and other data sources-data obtained with other spacecraft such as the HINOTORI, p78-1, and ISEE-3 spacecrafts, and with the Very Large Array (VLA) and many other ground-based instruments. Many coordinated data sets, unprecedented in their breadth of coverage and multiplicity of sources, had been obtained within the structure of the Solar Maximum Year (SMY). (2) Stimulate joint studies, and publication in the general scientific literature. The intended primary benefit was for informal collaborations to be started or broadened at the Workshops with subsequent publications. (3) Provide a special publication resulting from the Workshop.

  7. France uses the sun to cool its wine: the Banyuls winery solar cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-12-01

    The engineering consultancy Tecsol was asked to design a cooling system for a winery that would limit the variations in temperature during the year. Tecsol proposed a solar system. The total investment cost amounted to nearly two million French Francs (300,000 euros), almost double the cost of a conventional air-conditioning system. However, because the solar system reduced the conventional energy needs of the warehouse by about 40%, the French Agency for Environment and Energy Management (ADEME) provided a 37% subsidy for its rational use of energy. The 'Solarclim' solar installation has three functions: it produces hot water via 693 vacuum tube collectors with a useful surface of 130 m{sup 2}. The collectors are fixed to the roof of the wine cellar, which has an angle of 15 deg. Heat from the collectors is transferred to a 1000-litre hot water storage tank; it produces chilled water using a lithium bromide absorption plant with a nominal cooling capacity of 52 kW. This is housed in the technical premises on the lowest level and is used in conjunction with a 180 kW open-circuit cooling tower on the north facade; and the third function combines air-conditioning and, when necessary, space heating. The installation has been operating for 12 years with no particular problems. The equipment is environmentally friendly. The solar heat source avoids CO{sub 2} emissions, the absorption machine does not use CFCs or HCFCs, and the system is totally silent. (UK)

  8. Smart, passive sun facing surfaces

    Science.gov (United States)

    Hively, Lee M.

    1996-01-01

    An article adapted for selectively utilizing solar radiation comprises an absorptive surface and a reflective surface, the absorptive surface and the reflective surface oriented to absorb solar radiation when the sun is in a relatively low position, and to reflect solar radiation when the sun is in a relatively high position.

  9. A small mission concept to the Sun-Earth Lagrangian L5 point for innovative solar, heliospheric and space weather science

    Science.gov (United States)

    Lavraud, B.; Liu, Y.; Segura, K.; He, J.; Qin, G.; Temmer, M.; Vial, J.-C.; Xiong, M.; Davies, J. A.; Rouillard, A. P.; Pinto, R.; Auchère, F.; Harrison, R. A.; Eyles, C.; Gan, W.; Lamy, P.; Xia, L.; Eastwood, J. P.; Kong, L.; Wang, J.; Wimmer-Schweingruber, R. F.; Zhang, S.; Zong, Q.; Soucek, J.; An, J.; Prech, L.; Zhang, A.; Rochus, P.; Bothmer, V.; Janvier, M.; Maksimovic, M.; Escoubet, C. P.; Kilpua, E. K. J.; Tappin, J.; Vainio, R.; Poedts, S.; Dunlop, M. W.; Savani, N.; Gopalswamy, N.; Bale, S. D.; Li, G.; Howard, T.; DeForest, C.; Webb, D.; Lugaz, N.; Fuselier, S. A.; Dalmasse, K.; Tallineau, J.; Vranken, D.; Fernández, J. G.

    2016-08-01

    We present a concept for a small mission to the Sun-Earth Lagrangian L5 point for innovative solar, heliospheric and space weather science. The proposed INvestigation of Solar-Terrestrial Activity aNd Transients (INSTANT) mission is designed to identify how solar coronal magnetic fields drive eruptions, mass transport and particle acceleration that impact the Earth and the heliosphere. INSTANT is the first mission designed to (1) obtain measurements of coronal magnetic fields from space and (2) determine coronal mass ejection (CME) kinematics with unparalleled accuracy. Thanks to innovative instrumentation at a vantage point that provides the most suitable perspective view of the Sun-Earth system, INSTANT would uniquely track the whole chain of fundamental processes driving space weather at Earth. We present the science requirements, payload and mission profile that fulfill ambitious science objectives within small mission programmatic boundary conditions.

  10. Using Realistic MHD Simulations for Modeling and Interpretation of Quiet-Sun Observations with the Solar Dynamics Observatory Helioseismic and Magnetic Imager

    CERN Document Server

    Kitiashvili, Irina N; Lagg, Andreas

    2014-01-01

    The solar atmosphere is extremely dynamic, and many important phenomena develop on small scales that are unresolved in observations with the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO). For correct calibration and interpretation, it is very important to investigate the effects of small-scale structures and dynamics on the HMI observables, such as Doppler shift, continuum intensity, spectral line depth, and width. We use 3D radiative hydrodynamics simulations of the upper turbulent convective layer and the atmosphere of the Sun, and a spectro-polarimetric radiative transfer code to study observational characteristics of the Fe I 6173A line observed by HMI in quiet-Sun regions. We use the modeling results to investigate the sensitivity of the line Doppler shift to plasma velocity, and also sensitivities of the line parameters to plasma temperature and density, and determine effective line formation heights for observations of solar regions located at different dista...

  11. Alterations in fruit and vegetable beta-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers.

    Science.gov (United States)

    Ndawula, J; Kabasa, J D; Byaruhanga, Y B

    2004-08-01

    This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometry at 450 nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (pdrying. Open sun drying method caused the greatest b-carotene and vitamin C loss (58% and 84% respectively), while the visqueen-covered solar dryer caused the least loss (34.5% and 71% respectively). Blanching cowpea leaves improved b-carotene and vitamin C retention by 15% and 7.5% respectively. The b-carotene and vitamin C content of fresh ripe mango fruit was 5.9 and 164.3 mg/100g DM respectively. Similar to effects on cowpea leaves, the mango micronutrient content decreased (pdrying. The open sun drying method caused the greatest b-carotene (94.2%) and vitamin C (84.5%) loss, while the visqueen-covered solar dryer caused the least (73 and 53% respectively). These results show that the three solar drying methods cause significant loss of pro-vitamin A and vitamin C in dried fruits and vegetables. However, open sun drying causes the most loss and the visqueen-covered solar dryer the least, making the later a probable better drying technology for fruit and vegetable preservation. The drying technologies should be improved to enhance vitamin retention.

  12. The Solar System According to General Relativity: The Sun's Space Breaking Meets the Asteroid Strip

    Directory of Open Access Journals (Sweden)

    Borissova L.

    2010-04-01

    Full Text Available This study deals with the exact solution of Einstein’s field equations for a sphere of incompressible liquid without the additional limitation initially introduced in 1916 by Schwarzschild, by which the space-time metric must have no singularities. The ob- tained exact solution is then applied to the Universe, the Sun, and the planets, by the assumption that these objects can be approximated as spheres of incompressible liq- uid. It is shown that gravitational collapse of such a sphere is permitted for an object whose characteristics (mass, density, and size are close to the Universe. Meanwhile, there is a spatial break associated with any of the mentioned stellar objects: the break is determined as the approaching to infinity of one of the spatial components of the metric tensor. In particular, the break of the Sun’s space meets the Asteroid strip, while Jupiter’s space break meets the Asteroid strip from the outer side. Also, the space breaks of Mercury, Venus, Earth, and Mars are located inside the Asteroid strip (inside the Sun’s space break.

  13. Strength distribution of solar magnetic fields in photospheric quiet Sun regions

    CERN Document Server

    Velez, J C Ramirez; Semel, M

    2008-01-01

    The magnetic topology of the solar photosphere in its quietest regions is hidden by the difficulties to disentangle magnetic flux through the resolution element from the field strength of unresolved structures. The observation of spectral lines with strong coupling with hyperfine structure, like the observed MnI line at 553.7 nm, allows such differentiation. The main aim is to analyse the distribution of field strengths in the network and intranetwork of the solar photosphere through inversion of the MnI line at 553.7 nm. An inversion code for the magnetic field using the Principal Component Analysis (PCA) has been developed. Statistical tests are run on the code to validate it. The code has to draw information from the small-amplitude spectral feature oppearing in the core of the Stokes V profile of the observed line for field strengths below a certain threshold, coinciding with lower limit of the Paschen-Back effect in the fine structure of the involved atomic levels. The inversion of the observed profiles,...

  14. Photovoltaic test facility at Florida solar energy center

    Energy Technology Data Exchange (ETDEWEB)

    Atmanam, G.; Maytrott, C.; Wedekind, D.

    1984-05-01

    A photovoltaic flexible test facility has been developed at the Florida Solar Energy Center. The primary objective was to provide a test bed so that a variety of advanced technology subsystems (arrays and power conditioners) can be characterized and evaluated expeditiously in grid-interactive photovoltaic system operation. Also the systems' and subsystems' safety and reliability can be tested under imposed utility fault and extreme conditions. Such conditions include the utility outage, utility underand over-voltage and possible transient surges. The facility is designed to incorporate two complete parallel photovoltaic systems, one including the roof-mounted array and the other the tracking/adjustable array. The initial performance and test results are presented here along with a description of the facility.

  15. Fourier Transform Spectrometer observations of solar carbon monoxide. I - The fundamental and first overtone bands in the quiet sun

    Science.gov (United States)

    Ayres, T. R.; Testerman, L.

    1981-01-01

    Measurements of the 2200/cm fundamental and 4300/cm first overtone vibration-rotation band systems of solar carbon monoxide, were obtained with the Fourier Transform Spectrometer of the McMath telescope at Kitt Peak. The overtone measurements were taken at the east, north, and west heliocentric limbs, and at disk center. Observations of the strong fundamental bands were obtained at disk center and near the north limb. The low core brightness temperatures of the strongest fundamental carbon monoxide lines near the limb, reported previously by Noyes (1972) and Hall (1974), are confirmed. The possibility that thermal inhomogeneities might be responsible for the unusual behavior of the fundamental carbon dioxide lines have been examined. The somewhat discordant behavior of the fundamental lines at disk center compared with the north limb seems to favor a limb shadowing effect. The first overtone limb equivalent widths and the best-fit thermal and microvelocity models indicate a solar carbon abundance of 0.004 (on the scale with A sub H = 1) for an oxygen-to-carbon abundance ratio of 2.

  16. Space Science for Children: All about the Sun [Videotape].

    Science.gov (United States)

    1999

    This 23-minute videotape aims to give children, grades K-4, a broad understanding of the center of our solar system, the sun. It explains how the sun provides us with life-giving light and heat, how it's responsible for our seasons and weather, and why it's the primary source of energy on Earth. A hands-on activity in which children create their…

  17. On the Path to SunShot. The Role of Advancements in Solar Photovoltaic Efficiency, Reliability, and Costs

    Energy Technology Data Exchange (ETDEWEB)

    Woodhouse, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jones-Albertus, Rebecca [U.S. Dept. of Energy, Washington, DC (United States); Feldman, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Fu, Ran [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, Kelsey [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chung, Donald [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jordan, Dirk [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurtz, Sarah [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    This report examines the remaining challenges to achieving the competitive photovoltaic (PV) costs and large-scale deployment envisioned under the U.S. Department of Energy's SunShot Initiative. Solar-energy cost reductions can be realized through lower PV module and balance-of-system (BOS) costs as well as improved system efficiency and reliability. Numerous combinations of PV improvements could help achieve the levelized cost of electricity (LCOE) goals because of the tradeoffs among key metrics like module price, efficiency, and degradation rate as well as system price and lifetime. Using LCOE modeling based on bottom-up cost analysis, two specific pathways are mapped to exemplify the many possible approaches to module cost reductions of 29%-38% between 2015 and 2020. BOS hardware and soft cost reductions, ranging from 54%-77% of total cost reductions, are also modeled. The residential sector's high supply-chain costs, labor requirements, and customer-acquisition costs give it the greatest BOS cost-reduction opportunities, followed by the commercial sector, although opportunities are available to the utility-scale sector as well. Finally, a future scenario is considered in which very high PV penetration requires additional costs to facilitate grid integration and increased power-system flexibility--which might necessitate even lower solar LCOEs. The analysis of a pathway to 3-5 cents/kWh PV systems underscores the importance of combining robust improvements in PV module and BOS costs as well as PV system efficiency and reliability if such aggressive long-term targets are to be achieved.

  18. On the Path to SunShot - The Environmental and Public Health Benefits of Achieving High Penetrations of Solar Energy in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mai, Trieu [National Renewable Energy Lab. (NREL), Golden, CO (United States); Millstein, Dev [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Carpenter, Alberta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cohen, Stuart [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cole, Wesley [National Renewable Energy Lab. (NREL), Golden, CO (United States); Frew, Bethany [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heath, Garvin [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Monetizing the environmental health benefits of solar could add ~3.5¢/kWh to the value of solar energy (see Wiser et al. 2016). The monetary impacts due to environmental degradation and public health impacts seem far removed from the apparent “sticker price” of electricity. Yet quantifying these impacts is essential to understanding the true costs and benefits of solar and conventional generating technologies. Compared with fossil fuel generators, PV and CSP produce far lower lifecycle levels of greenhouse gas (GHG) emissions and harmful pollutants including fine particular matter (PM2.5), sulfur dioxide (SO2), and nitrogen oxides (NOx). Achieving the SunShot-level solar deployment targets—14% of U.S. electricity demand met by solar in 2030 and 27% in 2050—could reduce cumulative power-sector GHG emissions by 10% between 2015 and 2050, resulting in savings of $238–$252 billion. This is equivalent to 2.0–2.2 cents per kilowatt-hour of solar installed (¢/kWh-solar). Similarly, realizing these levels of solar deployment could reduce cumulative power-sector emissions of PM2.5 by 8%, SO2 by 9%, and NOx by 11% between 2015 and 2050. This could produce $167 billion in savings from lower future health and environmental damages, or 1.4¢/kWh-solar—while also preventing 25,000–59,000 premature deaths. To put this in perspective, the estimated 3.5¢/kWh-solar in benefits due to SunShot-level solar deployment is approximately equal to the additional LCOE reduction needed to make unsubsidized utility-scale solar competitive with conventional generators today. In addition, water savings from achieving the SunShot goals, could result in the 2015–2050 cumulative savings of 4% of total power-sector withdrawals and 9% of total power-sector consumption—a particularly important consideration for arid states where substantial solar will be deployed. Improving public health and the environment is but one aspect of solar’s many costs and benefits. Clearly, however

  19. Comprehensive Performance Analysis of Sun Tracker for Solar Energy%太阳能发电阳光跟踪器综合性能分析

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 陈海; 毛伙南; 郭金基; 梁洞庭; 郭诚; 王美芳; 曾玲玲

    2013-01-01

      The solar energy performance under the control of the sun tracker was tested. The system design of sun tracker and control push rod were introduced. The calculation of sun angle,its working principle,and operation function were discussed. Finally,application example was introduced.%  进行阳光跟踪器控制下太阳能电池板发电的对比测试;介绍阳光跟踪器及控制电动推杆系统设计;讨论太阳光角度的计算,分析其工作原理,检验其运行的功能;最后给出实例。

  20. Coherent Structure in Solar Wind C$^{6+}$/C$^{4+}$ Ionic Composition Data During the Quiet-Sun Conditions of 2008

    CERN Document Server

    Edmondson, J K; Lepri, S T; Zurbuchen, T H

    2013-01-01

    This analysis offers evidence of characteristic scale sizes in solar wind charge state data measured in-situ for thirteen quiet-sun Carrington rotations in 2008. Using a previously established novel methodology, we analyze the wavelet power spectrum of the charge state ratio C$^{6+}$/C$^{4+}$ measured in-situ by ACE/SWICS for 2-hour and 12-minute cadence. We construct a statistical significance level in the wavelet power spectrum to quantify the interference effects arising from filling missing data in the time series (Edmondson et al. 2013), allowing extraction of significant power from the measured data to a resolution of 24 mins. We analyze each wavelet power spectra for transient coherency, and global periodicities resulting from the superposition of repeating coherent structures. From the significant wavelet power spectra, we find evidence for a general upper-limit on individual transient coherency of $\\sim$10 days. We find evidence for a set of global periodicities between 4-5 hours and 35-45 days. We f...

  1. What Makes the Sun Tick? - The Origin of the Solar Cycle

    CERN Document Server

    Petrovay, K

    2000-01-01

    In contrast to the situation with the geodynamo, no breakthrough has been made in the solar dynamo problem for decades. Since the appearance of mean-field electrodynamics in the 1960's, the only really significant advance was in the field of flux tube theory and flux emergence calculations. These new results, together with helioseismic evidence, have led to the realization that the toroidal magnetic flux giving rise to activity phenomena must be stored and presumably generated below the convection zone proper, in what I will call the DOT (Dynamo-Overshoot-Tachoclyne) layer. The only segment of the problem we can claim to basically understand is the transport of flux from this layer to the surface. On the other hand, as reliable models for the DOT layer do not exist we are clueless concerning the precise mechanisms responsible for toroidal/poloidal flux conversion and for characteristic migration patterns (extended butterfly diagram) and periodicities. Even the most basic result of mean-field theory, the inter...

  2. Methods on Efficiently Relating Data from the Sun to In-situ Data at L1: An Application to the Slow Solar Wind

    Science.gov (United States)

    McQuillan, Maria; Viall, Nicholeen

    2017-01-01

    Understanding space weather has become increasingly important as scientists and spacecraft extend their reach further into the universe. The solar wind is highly ionized plasma that constantly bombards the earth. It causes compression and relaxation in our magnetosphere, and affects spacecraft and astronauts in outer space. There are two types of solar wind, fast wind and slow wind. The fast wind is considered to be steady in composition and speed, and travels at speeds greater than 500 km/s. The slow solar wind is known for being highly variable in composition and speed, and travels at speeds less than 500 km/s. Fast solar wind originates from coronal hole regions on the sun, while the slow solar wind’s origin is very controversial. There are currently two types of theories for slow solar wind. One theory involves wave heating dynamics, while the other contends that slow solar wind originates from magnetic reconnection that continually opens magnetic field lines. These models are currently under-constrained with both types able to reproduce the long-term, average behavior of the wind. To further constrain these models it was necessary to research small scale structure in the solar wind, however analyzing these structures pushes the limits of the current instrument capabilities. We developed techniques that provide an automated process to quickly generate results from multiple different analysis techniques, allowing the user to compare data from STEREO’s Heliospheric Imager (HI) and from data taken at L1. This increases the efficiency and ability to relate data from the sun in HI and data at Earth at L1. These techniques were applied to a study on the slow solar wind which lead to possible evidence for the S-Web model.

  3. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere II. Continuous Emission and Condensed Matter Within the Corona

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available The K-corona, a significant portion of the solar atmosphere, displays a continuous spectrum which closely parallels photospheric emission, though without the presence of overlying Fraunhofer lines. The E-corona exists in the same region and is characterized by weak emission lines from highly ionized atoms. For instance, the famous green emission line from coronium (FeXIV is part of the E-corona. The F-corona exists beyond the K/E-corona and, like the photospheric spectrum, is characterized by Fraunhofer lines. The F-corona represents photospheric light scattered by dust particles in the interplanetary medium. Within the gaseous models of the Sun, the K-corona is viewed as photospheric radiation which has been scattered by relativistic electrons. This scattering is thought to broaden the Fraunhofer lines of the solar spectrum such that they can no longer be detected in the K-corona. Thus, the gaseous models of the Sun account for the appearance of the K-corona by distorting photospheric light, since they are unable to have recourse to condensed matter to directly produce such radiation. Conversely, it is now advanced that the continuous emission of the K-corona and associated emission lines from the E-corona must be interpreted as manifestations of the same phenomenon: condensed matter exists in the corona. It is well-known that the Sun expels large amounts of material from its surface in the form of flares and coronal mass ejections. Given a liquid metallic hydrogen model of the Sun, it is logical to assume that such matter, which exists in the condensed state on the solar surface, continues to manifest its nature once expelled into the corona. Therefore, the continuous spectrum of the K-corona provides the twenty-seventh line of evidence that the Sun is composed of condensed matter.

  4. Appraising into the Sun: Six-State Solar Home Paired-Sale Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Berkeley National Laboratory

    2015-11-12

    Although residential solar photovoltaic (PV) installations have proliferated, PV systems on some U.S. homes still receive no value during an appraisal because comparable home sales are lacking. To value residential PV, some previous studies have employed paired-sales appraisal methods to analyze small PV home samples in depth, while others have used statistical methods to analyze large samples. Our first-of-its-kind study connects the two approaches. It uses appraisal methods to evaluate sales price premiums for owned PV systems on single-unit detached houses that were also evaluated in a large statistical study. Independent appraisers evaluated 43 recent home sales pairs in six states: California, Oregon, Florida, Maryland, North Carolina, and Pennsylvania. We compare these results with contributory-value estimates—based on income (using the PV Value® tool), gross cost, and net cost—as well as hedonic modeling results from the recent statistical study. The results provide strong, appraisal-based evidence of PV premiums in all states. More importantly, the results support the use of cost- and incomebased PV premium estimates when paired-sales analysis is impossible. PV premiums from the paired-sales analysis are most similar to net PV cost estimates. PV Value® income results generally track the appraised premiums, although conservatively. The appraised premiums are in agreement with the hedonic modeling results as well, which bolsters the suitability of both approaches for estimating PV home premiums. Therefore, these results will benefit valuation professionals and mortgage lenders who increasingly are encountering homes equipped with PV and need to understand the factors that can both contribute to and detract from market value.

  5. Selling Into the Sun: Price Premium Analysis of a Multi-State Dataset of Solar Homes

    Energy Technology Data Exchange (ETDEWEB)

    Adomatis, Sandra [Adomatis Appraisal Services, Punta Gorda, FL (United States); Jackson, Thomas [Texas A & M Univ. and Real Property Analytics Inc., College Station, TX (United States); Graff-Zivin, Joshua [Univ. of California, San Diego, CA (United States); Thayer, Mark [San Diego State Univ., CA (United States); Klise, Geoffrey [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hoen, Ben [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-01

    Capturing the value that solar photovoltaic (PV) systems may add to home sales transactions is increasingly important. Our study enhances the PV-home-valuation literature by more than doubling the number of PV home sales analyzed (22,822 homes in total, 3,951 of which are PV) and examining transactions in eight states that span the years 2002–2013. We find that home buyers are consistently willing to pay PV home premiums across various states, housing and PV markets, and home types; average premiums across the full sample equate to approximately $4/W or $15,000 for an average-sized 3.6-kW PV system. Only a small and non-statistically significant difference exists between PV premiums for new and existing homes, though some evidence exists of new home PV system discounting. A PV green cachet might exist, i.e., home buyers might pay a certain amount for any size of PV system and some increment more depending on system size. The market appears to depreciate the value of PV systems in their first 10 years at a rate exceeding the rate of PV efficiency losses and the rate of straightline depreciation over the asset’s useful life. Net cost estimates—which account for government and utility PV incentives—may be the best proxy for market premiums, but income-based estimates may perform equally well if they accurately account for the complicated retail rate structures that exist in some states. Although this study focuses only on host-owned PV systems, future analysis should focus on homes with third-party-owned PV systems.

  6. The structure of the Sun and the planets of the solar system from the viewpoint of mechanics of the inertless mass I

    CERN Document Server

    Shkurchenko, I Z

    2007-01-01

    In this monograph (written in 1973-1974) the author uses the theory of mechanics of the inertless mass to investigate the structure of heavenly bodies of the solar system. The structure of the Sun and planets is the sole reason of the character of their axial rotation, presence or absence of satellites and atmospheres. This structure is one of the main climatic factors for each planet and Sun. It determines the climate and its possible changes. Understanding these processes is very important for determining perspectives of the evolution of the Sun and the planets, including the Earth. This monograph was divided into two parts by editor in 2007. Since author has developed some theoretical positions of "Mechanics of liquids and gas, or mechanics of the inertless mass" (1971), the first Part contains these changes. The Part II contains the investigation that gives us new results and new meaning of the stored information about the Sun and the planets of the solar system. This monograph is addressed to specialists...

  7. Unusual Polar Activity of the Sun in the Northern Hemisphere and Its Implications for Solar Cycle 25

    Science.gov (United States)

    Gopalswamy, Nat; Masuda, Satoshi; Yashiro, Seiji; Akiyama, Sachiko; Shibasaki, Kiyoto

    2016-07-01

    Polar field strength in one solar cycle is known to indicate the strength (e.g., Sunspot number) and phase of the next cycle. In particular the polar field strength (or its proxies such as the polar coronal hole area and microwave polar brightness) during the minimum phase of a given cycle seem to be well correlated with the maximum sunspot number of the next cycle. Polar prominence eruptions and coronal mass ejections have also been found to be indicators of low polar field; their cessation signals the time of polarity reversal. While these indicators are present in the current cycle, significant differences are found regarding the phase lag between the two hemispheres and the duration of polar eruptions. We use data from the Nobeyama Radioheliograph, the Solar Dynamics Observatory, SOLIS, and Wilcox Solar Observatory to highlight these differences. We find that the north polar region of the Sun has near-zero field strength for more than three years. This is unusually long and caused by surges of both polarities heading toward the north pole that prevent the buildup of the polar field. This seems to be due to anti-Hale active regions that appeared around the 2012 peak sunspot activity in the northern hemisphere. The unusual condition is consistent with (i) the continued high-latitude prominence eruption, (ii) the extended period of high tilt angle of the heliospheric current sheet, (iii) the weak microwave polar brightness, and (iv) the lack of north polar coronal hole. On the other hand, the south polar field has started building up and the coronal hole has appeared in early 2015 because of large active regions of the correct tilt in the southern hemisphere during the 2014 peak of sunspot activity. The extended period of near-zero field in the north polar region should result in very weak and delayed sunspot activity in the northern hemisphere in cycle 25. On the other hand the south polar field has already increased significantly, suggesting that the activity in

  8. Why Study the Sun?

    Indian Academy of Sciences (India)

    Arvind Bhatnagar

    2006-06-01

    In this presentation we briefly describe the Sun through large number of illustrations and pictures of the Sun taken from early times to the present day space missions. The importance of the study of the Sun is emphasized as it is the nearest star which presents unparallelled views of surface details and numerous phenomena. Our Sun offers a unique celestial laboratory where a large variety of phenomena take place, ranging in temporal domain from a few milliseconds to several decades, in spatial domain from a few hundred kilometers to thousands of kilometers, and in the temperature domain from a few thousand degrees to several million degrees. Its mass motion ranges from thousandths to thousands of kilometers per second. Such an object provides us with a unique laboratory to study the state of matter in the Universe. The existing solar ground-based and space missions have already revealed several mysteries of the outer environment of our Sun and much more is going to come in the near future from planned new sophisticated ground-based solar telescopes and Space missions. The new technique of helioseismology has unravelled many secrets of the solar interior and has put the Standard Solar Model (SSM) on firm footing. The long-standing problem of solar neutrinos has been recently sorted out, and even the ‘back side’ view of the Sun can be seen using the technique of holographic helioseismology.

  9. Origin of the p-process radionuclides 92Nb and 146Sm in the early solar system and inferences on the birth of the Sun.

    Science.gov (United States)

    Lugaro, Maria; Pignatari, Marco; Ott, Ulrich; Zuber, Kai; Travaglio, Claudia; Gyürky, György; Fülöp, Zsolt

    2016-01-26

    The abundances of (92)Nb and (146)Sm in the early solar system are determined from meteoritic analysis, and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion of white dwarfs with mass above the Chandrasekhar limit is in agreement with the abundance of (53)Mn, another radionuclide present in the early solar system and produced in the same events. A consistent solution for (92)Nb and (53)Mn cannot be found within the current uncertainties and requires the (92)Nb/(92)Mo ratio in the early solar system to be at least 50% lower than the current nominal value, which is outside its present error bars. A different solution is to invoke another production site for (92)Nb, which we find in the α-rich freezeout during core-collapse supernovae from massive stars. Whichever scenario we consider, we find that a relatively long time interval of at least ∼ 10 My must have elapsed from when the star-forming region where the Sun was born was isolated from the interstellar medium and the birth of the Sun. This is in agreement with results obtained from radionuclides heavier than iron produced by neutron captures and lends further support to the idea that the Sun was born in a massive star-forming region together with many thousands of stellar siblings.

  10. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere I. Continuous Emission and Condensed Matter Within the Chromosphere

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available The continuous spectrum of the solar photosphere stands as the paramount observation with regard to the condensed nature of the solar body. Studies relative to Kirchhoff’s law of thermal emission (e.g. Robitaille P.-M. Kirchhoff’s law of thermal emission: 150 years. Progr. Phys., 2009, v. 4, 3–13. and a detailed analysis of the stellar opacity problem (Robitaille P.M. Stellar opacity: The Achilles’ heel of the gaseous Sun. Progr. Phys., 2011, v. 3, 93–99 have revealed that gaseous models remain unable to properly account for the generation of this spectrum. Therefore, it can be stated with certainty that the photosphere is comprised of condensed matter. Beyond the solar surface, the chromospheric layer of the Sun also generates a weak continuous spectrum in the visible region. This emission exposes the presence of material in the condensed state. As a result, above the level of the photosphere, matter exists in both gaseous and condensed forms, much like within the atmosphere of the Earth. The continuous visible spectrum associated with the chromosphere provides the twenty-sixth line of evidence that the Sun is condensed matter.

  11. Bio-Photoelectrochemical Solar Cells Incorporating Reaction Center and Reaction Center Plus Light Harvesting Complexes

    Science.gov (United States)

    Yaghoubi, Houman

    Harvesting solar energy can potentially be a promising solution to the energy crisis now and in the future. However, material and processing costs continue to be the most important limitations for the commercial devices. A key solution to these problems might lie within the development of bio-hybrid solar cells that seeks to mimic photosynthesis to harvest solar energy and to take advantage of the low material costs, negative carbon footprint, and material abundance. The bio-photoelectrochemical cell technologies exploit biomimetic means of energy conversion by utilizing plant-derived photosystems which can be inexpensive and ultimately the most sustainable alternative. Plants and photosynthetic bacteria harvest light, through special proteins called reaction centers (RCs), with high efficiency and convert it into electrochemical energy. In theory, photosynthetic RCs can be used in a device to harvest solar energy and generate 1.1 V open circuit voltage and ~1 mA cm-2 short circuit photocurrent. Considering the nearly perfect quantum yield of photo-induced charge separation, efficiency of a protein-based solar cell might exceed 20%. In practice, the efficiency of fabricated devices has been limited mainly due to the challenges in the electron transfer between the protein complex and the device electrodes as well as limited light absorption. The overarching goal of this work is to increase the power conversion efficiency in protein-based solar cells by addressing those issues (i.e. electron transfer and light absorption). This work presents several approaches to increase the charge transfer rate between the photosynthetic RC and underlying electrode as well as increasing the light absorption to eventually enhance the external quantum efficiency (EQE) of bio-hybrid solar cells. The first approach is to decrease the electron transfer distance between one of the redox active sites in the RC and the underlying electrode by direct attachment of the of protein complex

  12. Solar energy grid integration systems : final report of the Florida Solar Energy Center Team.

    Energy Technology Data Exchange (ETDEWEB)

    Ropp, Michael (Northern Plains Power Technologies, Brookings, SD); Gonzalez, Sigifredo; Schaffer, Alan (Lakeland Electric Utilities, Lakeland, FL); Katz, Stanley (Satcon Technology Corporation, Boston, MA); Perkinson, Jim (Satcon Technology Corporation, Boston, MA); Bower, Ward Isaac; Prestero, Mark (Satcon Technology Corporation, Boston, MA); Casey, Leo (Satcon Technology Corporation, Boston, MA); Moaveni, Houtan (Florida Solar Energy Center of the University of Central Florida, Cocoa, FL); Click, David (Florida Solar Energy Center of the University of Central Florida, Cocoa, FL); Davis, Kristopher (Florida Solar Energy Center of the University of Central Florida, Cocoa, FL); Reedy, Robert (Florida Solar Energy Center of the University of Central Florida, Cocoa, FL); Kuszmaul, Scott S.; Sena-Henderson, Lisa; David, Carolyn; Akhil, Abbas Ali

    2012-03-01

    Initiated in 2008, the Solar Energy Grid Integration Systems (SEGIS) program is a partnership involving the U.S. DOE, Sandia National Laboratories, private sector companies, electric utilities, and universities. Projects supported under the program have focused on the complete-system development of solar technologies, with the dual goal of expanding utility-scale penetration and addressing new challenges of connecting large-scale solar installations in higher penetrations to the electric grid. The Florida Solar Energy Center (FSEC), its partners, and Sandia National Laboratories have successfully collaborated to complete the work under the third and final stage of the SEGIS initiative. The SEGIS program was a three-year, three-stage project that include conceptual design and market analysis in Stage 1, prototype development and testing in Stage 2, and moving toward commercialization in Stage 3. Under this program, the FSEC SEGIS team developed a comprehensive vision that has guided technology development that sets one methodology for merging photovoltaic (PV) and smart-grid technologies. The FSEC team's objective in the SEGIS project is to remove barriers to large-scale general integration of PV and to enhance the value proposition of photovoltaic energy by enabling PV to act as much as possible as if it were at the very least equivalent to a conventional utility power plant. It was immediately apparent that the advanced power electronics of these advanced inverters will go far beyond conventional power plants, making high penetrations of PV not just acceptable, but desirable. This report summarizes a three-year effort to develop, validate and commercialize Grid-Smart Inverters for wider photovoltaic utilization, particularly in the utility sector.

  13. Sun-Earth Day 2005: Ancient Observatories: Timeless Knowledge

    Science.gov (United States)

    Thieman, J. R.; Cline, T.; Lewis, E.; Hawkins, I.; Odenwald, S.; Mayo, L.

    2005-05-01

    The NASA Sun-Earth Connection Education Forum (SECEF) annually promotes an event called Sun-Earth Day. For Sun-Earth Day 2005 SECEF has selected a theme called "Ancient Observatories: Timeless Knowledge. This year's Sun-Earth Day theme is your ticket to a fascinating journey through time as we explore centuries of sun watching by a great variety of cultures. From ancient solar motion tracking to modern solar activity monitoring the Sun has always occupied an important spot in mankind's quest to understand the Universe. Sun-Earth Day events usually are centered on the spring equinox around March 21, but this year there has already been a webcast from the San Francisco Exploratorium and the Native American ruins at Chaco Canyon, New Mexico on the day of winter solstice 2004. There will be another webcast on March 20 live from Chichen Itza, Mexico highlighting the solar alignment that makes a serpent appear on one of the ancient pyramids. The website http://sunearthday.nasa.gov has been developed to provide the necessary resources and opportunities for participation by scientists and educators in giving school or general public programs about Sun-Earth Day. The goal is to involve as much of the student population and the public in this event as possible and to help them understand the importance of the Sun for ancient and modern peoples. Through engaging activities available on the website, classrooms and museums can create their own event or participate in one of the opportunities we make available. Scientists, educators, amateur astronomers, and museums are invited to register on the website to receive a free packet of materials about Sun-Earth Day for use in making presentations or programs about the event. Past and future Sun-Earth Days will be discussed as well.

  14. Maximising the sun

    CSIR Research Space (South Africa)

    Conradie, Dirk CU

    2010-08-01

    Full Text Available South Africa is blessed with some of the best quality solar radiation in the world. In the light of this many exciting opportunities exist to utilize the sun to its full potential in the design of energy efficient buildings. Passive solar buildings...

  15. Our Explosive Sun

    Science.gov (United States)

    Brown, D. S.

    2009-01-01

    The Sun's atmosphere is a highly structured but dynamic place, dominated by the solar magnetic field. Hot charged gas (plasma) is trapped on lines of magnetic force that can snap like an elastic band, propelling giant clouds of material out into space. A range of ground-based and space-based solar telescopes observe these eruptions, particularly…

  16. Sun-Earth Day Connects History, Culture and Science

    Science.gov (United States)

    Cline, T.; Thieman, J.

    2003-12-01

    The NASA Sun-Earth Connection Education forum annually promotes and event called Sun-Earth Day: a national celebration of the Sun, the space around the Earth (geospace), and how all of it affects life on our planet. For the past 3 years this event has provided a venue by which classrooms, museums, planetaria, and at NASA centers have had a sensational time sharing stories, images, and activities related to the Sun-Earth connections and the views o fthe Sun from Earth. Each year we select a different theme by which NASA Space Science can be further related to cross-curricular activities. Sun-Earth Day 2002, "Celebrate the Equinox", drew parallels between Native American Cultures and NASA's Sun-Earth Connection research via cultural stories, interviews, web links, activities and Native American participation. Sun-Earth Day 2003, "Live From the Aurora", shared the beauty of the Aurora through a variety of activities and stories related to perspectives of Northern Peoples. Sun-Earth Day 2004 will share the excitement of the transit of Venus through comparisons of Venus with Earth and Mars, calculations of the distances to nearby stars, and the use of transits to identify extra-solar planets. Finally, Sun-Earth Day 2005 will bring several of these themes together by turning our focus to the history and culture surrounding ancient observatories such as Chaco Canyon, Machu Picchu, and Chichen Itza.

  17. On the Path to SunShot. Emerging Opportunities and Challenges in U.S. Solar Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Donald [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, Kelsey [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurup, Parthiv [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    This report provides insights into photovoltaic (PV) and concentrating solar power (CSP) manufacturing in the context of the U.S. Department of Energy's SunShot Initiative. Although global PV price reductions and deployment have been strong recently, PV manufacturing faces challenges. Slowing rates of manufacturing cost reductions, combined with the relatively low price of incumbent electricity generating sources in most large global PV markets, may constrain profit opportunities for firms and poses a potential challenge to the sustainable operation and growth of the global PV manufacturing base. In the United States, manufacturers also face a factors-of-production cost disadvantage compared with competing nations. However, the United States is one of the world's most competitive and innovative countries as well as one of the best locations for PV manufacturing. In conjunction with strong projected PV demand in the United States and across the Americas, these advantages could increase the share of PV technologies produced by U.S. manufacturers as the importance of innovation-driven PV cost reductions increases. Compared with PV, CSP systems are much more complex and require a much larger minimum effective scale, resulting in much higher total CAPEX requirements for system construction, lengthier development cycles, and ultimately higher costs of energy produced. The global lack of consistent CSP project development creates challenges for companies that manufacture specialty CSP components, and the potential lack of a near-term U.S. market could hinder domestic CSP manufacturers. However, global and U.S. CSP deployment is expected to expand beyond 2020, and U.S. CSP manufacturers could benefit from U.S. innovation advantages similar to those associated with PV. Expansion of PV and CSP manufacturing also presents U.S. job-growth opportunities.

  18. Fator de proteção solar: significado e controvérsias Sun protection factor: meaning and controversies

    Directory of Open Access Journals (Sweden)

    Sergio Schalka

    2011-06-01

    Full Text Available O Fator de Proteção Solar (FPS é o principal dado para quantificação da eficácia fotoprotetora de um filtro solar, sendo universalmente aceito. Seu método é baseado na determinação da Dose Eritematosa Mínima (DEM, definida como sendo a menor quantidade de energia necessária para o desencadeamento de eritema, em áreas de pele protegidas e não protegidas pelo produto em estudo. O valor do FPS é, então, calculado como a razão numérica entre a DEM da pele protegida e a da pele não protegida. A primeira publicação demonstrando um método para determinação do valor do FPS foi apresentada em 1978 pela agência norte-americana FDA, seguida por outras publicações do próprio FDA e de outras agências regulatórias internacionais. Apesar de ser considerado o método referência para quantificação da eficácia fotoprotetora de produtos tópicos, existem controvérsias na literatura acerca do método para determinação do FPS e sobre as implicações das reais condições de uso na proteção atingida na prática pelos usuáriosThe Sun Protection Factor (SPF is the most important data to quantify the effectiveness of a sunscreen, being universally accepted. The method is based on determining the minimum erythematous dose (MED, defined as the smallest amount of energy required for triggering the erythema, in areas of protected and unprotected skin. The SPF value is then calculated as the ratio between the MED of protected and unprotected skin. The first publication of a method for determining the SPF was presented in 1978 by the U.S. FDA agency, followed by other publications of FDA and other international regulatory agencies. Although considered the reference method for quantification of sunscreen efficacy of topical products, there are controversies in literature about the method for determining the SPF and the implications of the real conditions of use in the protection achieved in practice by users

  19. Magnetohydrodynamics of the sun

    CERN Document Server

    Priest, Eric

    2014-01-01

    Magnetohydrodynamics of the Sun is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamics, taking account of enormous advances in understanding since that date. It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field, which is responsible for many fascinating dynamic phenomena. Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass ejections, and the acceleration of the solar wind by reconnection or wave-turbulence. It is essential reading for graduate students and researchers in solar physics and related fields of astronomy, plasma physics and fluid dynamics. Problem sets and other resources are available at www.cambridge.org/9780521854719.

  20. Epidemiologic characteristics of oral cancer:single-center analysis of 4097 patients from the Sun Yat-sen University Cancer Center

    Institute of Scientific and Technical Information of China (English)

    Ji Zhang; Ming Song; Fan Gao; AnKui Yang; WenKuan Chen; ShuWei Chen; Huan Li; Xing Zhang; ZhongYuan Yang; XinLin Chen

    2016-01-01

    Background: Oral cancer is a common type of head and neck cancers. Knowing its epidemiologic characteristics is crucial to preventing, diagnosing, and treating this cancer. This study aimed to explore the epidemiologic characteris‑tics of oral cancer in South China. Methods: We retrospectively analyzed data from 4097 oral cancer patients treated at the Sun Yat‑sen University Cancer Center between 1960 and 2013. We compared the age of onset, sex ratio, pathologic type, and primary tumor location among three subcultural areas (Guangfu, Hakka, and Chaoshan) and between an economically developed region and a less‑developed one in Guangdong. Results: Overall, oral cancer had a male‑to‑female ratio of approximately 2:1, and this ratio decreased over time. Oral cancer occurred mostly in patients of 45–64 years old (54.5%), and the percentage of older patients gradually increased over time. The most common tumor location was the tongue. Squamous cell carcinoma was the predomi‑nant pathologic type. The percentage of blood type O in oral cancer patients was lower than that in the healthy pop‑ulation. The male‑to‑female ratio in the Chaoshan area was higher than that in the Guangfu and Hakka areas, whereas the age of disease onset in Guangfu was higher than that in Hakka and Chaoshan. The male‑to‑female ratio was lower and the age of disease onset was higher in the economically developed region than in the less‑developed region. Conclusion: The incidence of oral cancer in South China presents typical characteristics to which doctors should pay attention when diagnosing and treating oral cancer patients.

  1. Earth's Heat Source - The Sun

    CERN Document Server

    Manuel, Oliver K

    2009-01-01

    The Sun encompasses planet Earth, supplies the heat that warms it, and even shakes it. The United Nation Intergovernmental Panel on Climate Change (IPCC) assumed that solar influence on our climate is limited to changes in solar irradiance and adopted the consensus opinion of a Hydrogen-filled Sun, the Standard Solar Model (SSM). They did not consider the alternative solar model and instead adopted another consensus opinion: Anthropogenic greenhouse gases play a dominant role in climate change. The SSM fails to explain the solar wind, solar cycles, and the empirical link of solar surface activity with Earth changing climate. The alternative solar model, that was molded from an embarrassingly large number of unexpected observations revealed by space-age measurements since 1959, explains not only these puzzles but also how closely linked interactions between the Sun and its planets and other celestial bodies induce turbulent cycles of secondary solar characteristics that significantly affect Earth climate.

  2. Sun position calculator (SPC) for Landsat imagery with geodetic latitudes

    Science.gov (United States)

    Seong, Jeong C.

    2015-12-01

    Landsat imagery comes with sun position information such as azimuth and sun elevation, but they are available only at the center of a scene. To aid in the use of Landsat imagery for various solar radiation applications such as topographic correction, solar power, urban heat island, agriculture, climate and vegetation, it is necessary to calculate the sun position information at every pixel. This research developed a PC application that creates sun position data layers in ArcGIS at every pixel in a Landsat scene. The SPC program is composed of two major routines - converting universal transverse Mercator (UTM) projection coordinates to geographic longitudes and latitudes, and calculating sun position information based on the Meeus' routine. For the latter, an innovative method was also implemented to account for the Earth's flattening on an ellipsoid. The Meeus routine implemented in this research showed about 0.2‧ of mean absolute difference from the National Renewable Energy Laboratory (NREL) Solar Position Algorithm (SPA) routine when solar zenith and azimuth angles were tested with every 30 min data at four city locations (Fairbanks, Atlanta, Sydney and Rio Grande) on June 30, 2014. The Meeus routine was about ten times faster than the SPA routine. Professionals who need the Sun's position information for Landsat imagery will benefit from the SPC application.

  3. Comparison under a simulated sun of two black-nickel-coated flat-plate solar collectors with a nonselective black-paint-coated collector

    Science.gov (United States)

    Simon, F. F.

    1975-01-01

    A performance evaluation was made of two, black nickel coated, flat plate solar collectors. Collector performance was determined under a simulated sun for a wide range of inlet temperatures, including the temperature required for solar powered absorption air conditioning. For a basis of comparison a performance test was made on a traditional, two glass, nonselective, black paint coated, flat plate collector. Performance curves and performance parameters are presented to point out the importance of the design variables which determine an efficient collector. A black nickel coated collector was found to be a good performer at the conditions expected for solar powered absorption air conditioning. This collector attained a thermal efficiency of 50 percent at an inlet temperature of 366 K (200 F) and an incident flux of 946 watts/sq m (300 Btu/hr-sq ft).

  4. 77 FR 46768 - Notice of Intent To Prepare an Environmental Impact Statement for the Moapa Solar Energy Center...

    Science.gov (United States)

    2012-08-06

    ... Solar Energy Center on the Moapa River Indian Reservation, Clark County NV AGENCY: Bureau of Indian... (EIS) that evaluates a solar energy generation center on the Moapa River Indian Reservation. This... Proposed Action consists of constructing and operating a solar generation energy center, consisting of...

  5. The AIA Solar Learning Center: Taking Inquiry-based EPO Online

    Science.gov (United States)

    Wills-Davey, Meredith; Attrill, G. D. R.; Engell, A.

    2009-05-01

    The observations of the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory (SDO-AIA) are expected to be groundbreaking within the field of heliophysics. To properly promote and explain the data produced by AIA, it is important that an innovative EPO effort be put forth. This has led to the development of "The AIA Solar Learning Center” (SLC), an inquiry-based educational website geared towards teaching about AIA and the Sun in general. The goal of the SLC is to provide K-12 students, teachers, parents, and homeschoolers with information and education about the Sun, primarily through hands-on activity modules that explain different aspects of our nearest star and the methods of observing it. While each module ultimately aims to impart information about the Sun or some related physical process, the activities also range across a host of different disciplines, including geology, chemistry, history, music, and art. In order to make the content applicable and accessible, activities are tailored to multiple difficulty levels, catering to different age groups. There is also a strong push towards facilitating teachers; activities are designed to fulfill specific teaching standards, and a host of additional teaching material is provided, including lesson plans and powerpoint presentations. Ultimately, the SLC aims to make science and the Sun inviting and accessible. The "Meet the Scientists” page will provide pictures and personal bios of participating scientists. Students will have the opportunity to interactively ask solar-related questions. There is even a host of lighter fare, such as a solar music playlist and links to relevant Facebook pages.

  6. Sun, Earth and Sky

    Science.gov (United States)

    Lang, Kenneth R.

    1995-01-01

    The Sun is enveloped by a hot, tenuous million-degree corona that expands to create a continuous solar wind that sweeps past all the planets and fills the heliosphere. The solar wind is modulated by strong gusts that are initiated by powerful explosions on the Sun, including solar flares and coronal mass ejections. This dynamic, invisible outer atmosphere of the Sun is currently under observation with the soft X-ray telescope aboard the Yohkoh spacecraft, whose results are presented. We also show observations from the Ulysses spacecraft that is now passing over the solar pole, sampling the solar wind in this region for the first time. Two other spacecraft, Voyager 1 and 2, have recently detected the outer edge of the invisible heliosphere, roughly halfway to the nearest star. Magnetic solar activity, the total radiative output from the Sun, and the Earth's mean global surface temperature all vary with the 11-year sunspot cycle in which the total number of sunspots varies from a maximum to a minimum and back to a maximum again in about 11 years. The terrestrial magnetic field hollows out a protective magnetic cavity, called the magnetosphere, within the solar wind. This protection is incomplete, however, so the Sun feeds an unseen world of high-speed particles and magnetic fields that encircle the Earth in space. These particles endanger spacecraft and astronauts, and also produce terrestrial aurorae. An international flotilla of spacecraft is now sampling the weak points in this magnetic defense. Similar spacecraft have also discovered a new radiation belt, in addition to the familiar Van Allen belts, except fed by interstellar ions instead of electrons and protons from the Sun.

  7. Ventilated solar walls. Nature Center Vestamager; Ventilerede solvaegge. Naturcenter Vestamager

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, T.P.

    1999-05-01

    The aim of the project is to demonstrate ventilated solar walls in practice, including how the walls may be fitted in architecturally and structurally in an actual building. The solar walls are mechanically ventilated with recirculation of indoor air. Each of the two solar walls has the dimension 1.77 x 1.77 m - total 3.13 m{sup 2}. The transparent area makes up 2.71 m{sup 2} pr. solar wall. The covering layer consists of 4 mm hardened glass with low emission covering. A black absorber of anodised aluminium is mounted between covering layer and back covering of galvanised steel. The air flow takes place in a 20 mm slit between back covering and absorber. Covering layer, absorber and back covering is mounted in powder finished aluminium frames integrated in the facade. The use of the building implies that there is only rarely a need for heat supply during the evening, which is the reason why the solar walls are not constructed to store solar heat. The glass area in the building is so small, that the solar walls only to a small extent compete with solar radiation through the doors and windows. (EHS)

  8. Liquid Metallic Hydrogen III. Intercalation and Lattice Exclusion Versus Gravitational Settling and Their Consequences Relative to Internal Structure, Surface Activity, and Solar Winds in the Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-04-01

    Full Text Available Invocation of a liquid metallic hydrogen model (Robitaille P.M. Liquid Metallic Hydro- gen: A Building Block for the Liquid Sun. Progr. Phys ., 2011, v. 3, 60–74; Robitaille P.M. Liquid Metallic Hydrogen II: A Critical Assessment of Current and Primordial He- lium Levels in Sun. Progr. Phys ., 2013, v. 2, 35–47 brings with it a set of advantages for understanding solar physics which will always remain unavailable to the gaseous models. Liquids characteristically act as solvents and incorporate solutes within their often fleeting structural matrix. They possess widely varying solubility products and often reject the solute altogether. In that case, the solute becomes immiscible. “Lattice exclusion” can be invoked for atoms which attempt to incorporate themselves into liquid metallic hydrogen. In order to conserve the integrity of its conduction bands, it is antic- ipated that a graphite-like metallic hydrogen lattice should not permit incorporation of other elements into its in-plane hexagonal hydrogen framework. Based on the physics observed in the intercalation compounds of graphite, non-hydrogen atoms within liq- uid metallic hydrogen could reside between adjacent hexagonal proton planes. Conse- quently, the forces associated with solubility products and associated lattice exclusion envisioned in liquid metallic hydrogen for solutes would restrict gravitational settling. The hexagonal metallic hydrogen layered lattice could provide a powerful driving force for excluding heavier elements from the solar body. Herein lies a new exfoliative force to drive both surface activity (flares, coronal mass ejections, prominences and solar winds with serious consequences relative to the p–p reaction and CNO cycle in the Sun. At the same time, the idea that non-hydrogen atomic nuclei can exist between layers of metallic hydrogen leads to a fascinating array of possibilities with respect to nucleosyn- thesis. Powerful parallels can be drawn to the

  9. The energy construction of the Sun and planets of the solar system from the viewpoint of mechanics of the inertless mass

    CERN Document Server

    Shkurchenko, I Z

    2010-01-01

    This monograph (1977) is a continuation of the monograph "The construction of the Sun and planets of the solar system from the viewpoint of mechanics of the inertless mass" (refer to: http://arxiv.org/abs/physics/0701258, part 1, http://arxiv.org/abs/physics/0701259, part 2). This manuscript concerning the studies of the energy structure of the Sun and planets was discovered in the archive of the author in 2009. Being a draft version, it contains some remarks of the author on other subjects and has a free style. The editor has omitted all the retreats of the author. Thus, the work is a final study and is intended for the reader who is familiar with previous studies of the author that are placed in this Archive.

  10. Solar-energy heats a transportation test center--Pueblo, Colorado

    Science.gov (United States)

    1981-01-01

    Petroleum-base, thermal energy transport fluid circulating through 583 square feet of flat-plate solar collectors accumulates majority of energy for space heating and domestic hot-water of large Test Center. Report describes operation, maintenance, and performance of system which is suitable for warehouses and similar buildings. For test period from February 1979 to January 1980, solar-heating fraction was 31 percent, solar hot-water fraction 79 percent.

  11. Self-generated clouds of micron-sized particles as a promising way of a Solar Probe shielding from intense thermal radiation of the Sun

    Science.gov (United States)

    Dombrovsky, Leonid A.; Reviznikov, Dmitry L.; Kryukov, Alexei P.; Levashov, Vladimir Yu

    2017-10-01

    An effect of shielding of an intense solar radiation towards a solar probe with the use of micron-sized SiC particles generated during ablation of a composite thermal protection material is estimated on a basis of numerical solution to a combined radiative and heat transfer problem. The radiative properties of particles are calculated using the Mie theory, and the spectral two-flux model is employed in radiative transfer calculations for non-uniform particle clouds. A computational model for generation and evolution of the cloud is based on a conjugated heat transfer problem taking into account heating and thermal destruction of the matrix of thermal protection material and sublimation of SiC particles in the generated cloud. The effect of light pressure, which is especially important for small particles, is also taken into account. The computational data for mass loss due to the particle cloud sublimation showed the low value about 1 kg/m2 per hour at the distance between the vehicle and the Sun surface of about four radii of the Sun. This indicates that embedding of silicon carbide or other particles into a thermal protection layer and the resulting generation of a particle cloud can be considered as a promising way to improve the possibilities of space missions due to a significant decrease in the vehicle working distance from the solar photosphere.

  12. solarFLAG hare and hounds: on the extraction of rotational p-mode splittings from seismic, Sun-as-a-star data

    CERN Document Server

    Chaplin, W J; Baudin, F; Boumier, P; Elsworth, Y; Fletcher, S T; Fossat, E; García, R A; Isaak, G R; Jiménez, A; Jiménez-Reyes, S J; Lazrek, M; Leibacher, J W; Lochard, J; New, R; Pallé, P L; Regulo, C; Salabert, D; Seghouani, N; Toutain, T; Wachter, R

    2006-01-01

    We report on results from the first solar Fitting at Low-Angular degree Group (solar FLAG) hare-and-hounds exercise. The group is concerned with the development of methods for extracting the parameters of low-l solar p mode data (`peak bagging'), collected by Sun-as-a-star observations. Accurate and precise estimation of the fundamental parameters of the p modes is a vital pre-requisite of all subsequent studies. Nine members of the FLAG (the `hounds') fitted an artificial 3456-d dataset. The dataset was made by the `hare' (WJC) to simulate full-disc Doppler velocity observations of the Sun. The rotational frequency splittings of the l=1, 2 and 3 modes were the first parameter estimates chosen for scrutiny. Significant differences were uncovered at l=2 and 3 between the fitted splittings of the hounds. Evidence is presented that suggests this unwanted bias had its origins in several effects. The most important came from the different way in which the hounds modeled the visibility ratio of the different rotati...

  13. Ocmulgee National Monument Visitor Center solar heating and cooling system design review data

    Energy Technology Data Exchange (ETDEWEB)

    1978-05-01

    This document has been prepared as a part of the detailed design of the solar heating and cooling system to be installed at the Ocmulgee National Monument Visitor Center. It describes the 50 percent design review data for this site, and discusses the design approaches, system trade studies, subsystem design and development approach, solar collectors, preliminary specifications and other related information.

  14. Solar energy for district heating and group centers

    Energy Technology Data Exchange (ETDEWEB)

    Wahlman, E.; Zinko, H.; Hultmark, G.; Isakson, P.; Karlsson, B.; Margen, P.

    1984-01-01

    The report presents the technique and the state of the art concerning solar energy in a district heating system by the turn of the year 1983/84. The market potential and the cost accounting and the development are discussed. An estimate of the energy production of solar collector systems is presented. 11 different pilot and demonstration plants for solar district heating are described, particularly the plants at Tumba, Knivsta, Studsvik, Torvalla, Ingelstad and Lyckebo. The experience and the general trend is expressed as a change towards large units and a reduction of cost. Continued research and development is recommended.

  15. On the Path to SunShot. Emerging Issues and Challenges in Integrating High Levels of Solar into the Electrical Generation and Transmission System

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Clark, Kara [National Renewable Energy Lab. (NREL), Golden, CO (United States); O' Connell, Matt [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    This report examines how the bulk power system may need to evolve to accommodate the increased photovoltaic (PV) penetration resulting from achievement of the U.S. Department of Energy's SunShot cost targets. The variable and uncertain nature of PV-generated electricity presents grid-integration challenges. For example, the changing net load associated with high midday PV generation and low electricity demand can create 'overgeneration' that requires curtailment of PV output and reduces PV's value and cost-competitiveness. Accommodating the changes in net load resulting from increased variable generation requires enhancements to a power system's 'flexibility,' or ability to balance supply and demand over multiple time scales through options including changes in system operation, flexible generation, reserves from solar, demand response, energy storage, and enhanced transmission and regional coordination. For utility-scale PV with a baseline SunShot levelized cost of electricity (LCOE) of 6 cents/kWh, increasing the annual energy demand met by solar energy from 10% to 20% would increase the marginal LCOE of PV from 6 cents/kWh to almost 11 cents/kWh in a California grid system with limited flexibility. However, increasing system flexibility could minimize solar curtailment and keep PV cost-competitive at penetrations at least as high as 25%. In the longer term, energy storage technologies--such as concentrating solar power with thermal energy storage--could facilitate the cost-effective integration of even higher PV penetration. Efficient deployment of the grid-flexibility options needed to maintain solar's value will require various innovations, from the development of communication, control, and energy storage technologies to the implementation of new market rules and operating procedures.

  16. Reconnection on the Sun

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    , erupting from the solar surface.Snapshots from the SDO side view (left and center) and STEREO overhead view (right). The three rows show the time evolution of the double-loop structure after the initial flare. In the STEREO view, you can see the central footpoints of the loops slip to the left. [Gou et al. 2016]In the SDO observations presented by Chen and collaborators, the pre-flare/CME structures look remarkably like the structures predicted in the breakout model. Sequential heating of loops can be seen as the breakout reconnection starts, followed by anenormous flare and CME as the lower loops erupt outward.Study 2: Slipping ReconnectionA team of scientists from the University of Science and Technology of China, led by Tingyu Gou and Rui Liu, have presented the first stereoscopic observation of slipping reconnection in the Sun, made by the two-spacecraft Solar Terrestrial Relations Observatory (STEREO).In slipping reconnection, magnetic field lines continuously exchange connectivities with their neighbors, causing them to slip through plasma. Observations by STEREO of a flaring double-loop system revealed that the central footpoints the endpoints where the loops are anchored to the solar surface slipped sideways after a flare.The authors model of the double-loop structure at two different times, during which the central footpoint slips from point C to D. Projections onto the XY and YZ planes show STEREOs and SDOs views, respectively. [Gou et al. 2016]The authors reconstructed a 3D model of the loop system using the overhead observations from STEREO and a simultaneous side view from SDO. They speculate that the slipping reconnection was likely triggered by the initial solar flare.Double BonusCheck out the videos belowto watch these processes happen!This first video is from Chen et al. 2016, and shows the SDO view of coronal loops in three wavelengths. If you watch carefully, you can see the sequential brightening of loops signs of the breakout reconnection before the

  17. Earth-Affecting Solar Causes Observatory (EASCO): A Potential International Living with a Star Mission from Sun-Earth L5

    Science.gov (United States)

    Gopalswamy, N.; Davila, J. M.; St Cyr, O. C.; Sittler, E. C.; Auchere, F.; Duvall, Jr. T. L.; Hoeksema, J. T.; Maksimovic, M.; MacDowall, R. J.; Szabo, A.; Collier, M. R.

    2011-01-01

    This paper describes the scientific rationale for an L5 mission and a partial list of key scientific instruments the mission should carry. The L5 vantage point provides an unprecedented view of the solar disturbances and their solar sources that can greatly advance the science behind space weather. A coronagraph and a heliospheric imager at L5 will be able to view CMEs broadsided, so space speed of the Earth-directed CMEs can be measured accurately and their radial structure discerned. In addition, an inner coronal imager and a magnetograph from L5 can give advance information on active regions and coronal holes that will soon rotate on to the solar disk. Radio remote sensing at low frequencies can provide information on shock-driving CMEs, the most dangerous of all CMEs. Coordinated helioseismic measurements from the Sun Earth line and L5 provide information on the physical conditions at the base of the convection zone, where solar magnetism originates. Finally, in situ measurements at L5 can provide information on the large-scale solar wind structures (corotating interaction regions (CIRs)) heading towards Earth that potentially result in adverse space weather.

  18. Thermal performance evaluation of the Northrop model NSC-01-0732 concentrating solar collector array at outdoor conditions. [Marshall Space Flight Center solar house test facility

    Science.gov (United States)

    1979-01-01

    The thermal efficiency of the concentrating, tracking solar collector was tested after ten months of operation at the Marshall Space Flight Center solar house. The test procedures and results are presented.

  19. Sun Allergy

    Science.gov (United States)

    ... if you have unusual, bothersome skin reactions after exposure to sunlight. For severe or persistent symptoms, you may need ... m. when the sun is brightest. Avoid sudden exposure to lots of sunlight. Many people have sun allergy symptoms when they ...

  20. The velocity of the dust near the Sun during the Solar Eclipse of March 29, 2006 and sungrazing comets

    CERN Document Server

    Shestakova, L I; Demchenko, B I; Rspaev, F K

    2010-01-01

    The measurements of the Doppler shifts of the Fraunhofer lines, scattered by the dust grains in the solar F-corona, provides the insight on the velocity field of the dust and hence on its origin. We report on such measurements obtained during the total eclipse of March 29, 2006. We used a Fabry-P\\'erot interferometer with the FOV of 5.9 degrees and the spectral resolution of about 5000 to record Fraunhofer spectral lines scattered by the dust of the F-Corona. The spectral region was centered on the MgI 5172.69 A line. The measured line-on-sight velocities with the amplitude in the range from -10 to 10 km/s show that during our observations the dust grains were on the orbit with a retrograde motion in a plane nearly perpendicular to the ecliptics. This indicates their cometary origin. Indeed, at the end of March, 2006, SOHO recorded several sungrazing comets with the orbital elements close to what was deduced from our measurements. We conclude that the contribution of comets to the dust content in the region c...

  1. The sun, our star

    Science.gov (United States)

    Noyes, R. W.

    Observational data, analytical models, and instrumentation used to study the sun and its evolution are detailed, and attention is given to techniques for converting solar energy to useful power on earth. The star ignited when the mutual gravitational attractions of dust and vapor in a primordial cloud in the Galaxy caused an in-rush of accelerating particles which eventually became dense enough to ignite. The heat grew until inward rushing matter was balanced by outward moving radiative forces. The planets formed from similar debris, and solar radiation is suggested to have triggered the chemical reactions giving rise to life on earth. Visual, spectroscopic, coronagraphic, and UV observations of the sun from the ground and from spacecraft, particularly Skylab, are described, together with features of the solar surface, magnetic field, sunspots, and coronal loops. Models for the processes that occur in the solar interior are explored, as are the causes of solar flares. Attention is given to solar cells, heliostat arrays, wind turbines, and water turbines as means to convert, either directly or indirectly, the earth-bound solar energy to electrical and thermal power. Finally, the life cycle of the sun, about 9 billion yr in duration, is summarized, noting the current status of midlife.

  2. ON THE CONSTANCY OF THE DIAMETER OF THE SUN DURING THE RISING PHASE OF SOLAR CYCLE 24

    Energy Technology Data Exchange (ETDEWEB)

    Meftah, M.; Hauchecorne, A.; Irbah, A. [Université de Versailles Saint-Quentin-en-Yvelines, Sorbonne Universités, Université Paris VI—Pierre et Marie Curie, CNRS/INSU, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Institut Pierre Simon Laplace (IPSL), 11 Boulevard d’Alembert, 78280 Guyancourt (France); Corbard, T.; Ikhlef, R.; Morand, F.; Renaud, C. [Université de Nice Sophia-Antipolis, CNRS, Laboratoire Lagrange, UMR 7293, Observatoire de la Côte d’Azur (OCA), Boulevard de l’Observatoire, 06304 Nice (France); Riguet, F.; Pradal, F., E-mail: Mustapha.Meftah@latmos.ipsl.fr, E-mail: Thierry.Corbard@oca.eu [Safran REOSC, Avenue de la Tour Maury, 91280 Saint-Pierre-du-Perray (France)

    2015-07-20

    The potential relationship between solar activity and changes in solar diameter remains the subject of debate and requires both models and measurements with sufficient precision over long periods of time. Using the PICARD instruments, we carried out precise measurements of variations in solar diameter during the rising phase of solar cycle 24. From new correction methods we found changes in PICARD space telescope solar radius amplitudes that were less than ±20 mas (i.e. ±14.5 km) for the years 2010–2011. Moreover, PICARD ground-based telescope solar radius amplitudes are smaller than ±50 mas from 2011 to 2014. Our observations could not find any direct link between solar activity and significant fluctuations in solar radius, considering that the variations, if they exist, are included within this range of values. Further, the contribution of solar radius fluctuations is low with regard to variations in total solar irradiance. Indeed, we find a small variation of the solar radius from space measurements with a typical periodicity of 129.5 days, with ±6.5 mas variation.

  3. The detection of global convection on the sun by an analysis of line shift data of the John M. Wilcox Solar Observatory at Stanford University

    Science.gov (United States)

    Yoshimura, Hirokazu

    1987-01-01

    An analysis of the absorption line shift data of the John M. Wilcox Solar Observatory at Stanford University has yielded signatures of the existence of global convection on the sun. These include persistent periodic time variations in the east-west component of the velocity fields defined by fitting a slope to the line shift data in a certain longitude window at a specified latitude and longitude by the least squares method. The amplitude of the velocity fields estimated from these variations is of the order of 100 m/s. The results of the analysis also suggest that several modes of global convection coexist in the solar convection zone. Details of the analysis are given.

  4. Vision Algorithm for the Solar Aspect System of the High Energy Replicated Optics to Explore the Sun Mission

    Science.gov (United States)

    Cramer, Alexander Krishnan

    2014-01-01

    This work covers the design and test of a machine vision algorithm for generating high- accuracy pitch and yaw pointing solutions relative to the sun on a high altitude balloon. It describes how images were constructed by focusing an image of the sun onto a plate printed with a pattern of small cross-shaped fiducial markers. Images of this plate taken with an off-the-shelf camera were processed to determine relative position of the balloon payload to the sun. The algorithm is broken into four problems: circle detection, fiducial detection, fiducial identification, and image registration. Circle detection is handled by an "Average Intersection" method, fiducial detection by a matched filter approach, and identification with an ad-hoc method based on the spacing between fiducials. Performance is verified on real test data where possible, but otherwise uses artificially generated data. Pointing knowledge is ultimately verified to meet the 20 arcsecond requirement.

  5. Solar Physics at Evergreen: Solar Dynamo and Chromospheric MHD

    Science.gov (United States)

    Zita, E. J.; Maxwell, J.; Song, N.; Dikpati, M.

    2006-12-01

    We describe our five year old solar physics research program at The Evergreen State College. Famed for its cloudy skies, the Pacific Northwest is an ideal location for theoretical and remote solar physics research activities. Why does the Sun's magnetic field flip polarity every 11 years or so? How does this contribute to the magnetic storms Earth experiences when the Sun's field reverses? Why is the temperature in the Sun's upper atmosphere millions of degrees higher than the Sun's surface temperature? How do magnetic waves transport energy in the Sun’s chromosphere and the Earth’s atmosphere? How does solar variability affect climate change? Faculty and undergraduates investigate questions such as these in collaboration with the High Altitude Observatory (HAO) at the National Center for Atmospheric Research (NCAR) in Boulder. We will describe successful student research projects, logistics of remote computing, and our current physics investigations into (1) the solar dynamo and (2) chromospheric magnetohydrodynamics.

  6. Physics of the sun

    CERN Document Server

    Holzer, Thomas; Mihalas, Dimitri; Ulrich, Roger

    1986-01-01

    This volume, together with its two companion volumes, originated in a study commis­ sioned by the United States National Academy of Sciences on behalf of the National Aeronautics and Space Administration. A committee composed of Tom Holzer, Dimitri Mihalas, Roger Ulrich and myself was asked to prepare a comprehensive review of current knowledge concerning the physics of the sun. We were fortunate in being able to persuade many distinguished scientists to gather their forces for the preparation of 21 separate chapters covering not only solar physics but also relevant areas of astrophysics and solar-terrestrial relations. It proved necessary to divide the chapters into three separate volumes that cover three different aspects of solar physics. Volumes 1 and 2 are concerned with 'The Solar Interior' and with 'The Solar Atmosphere'. This volume, devoted to 'Astrophysics and Solar-Terrestrial Relations', focuses on problems of solar physics from these two different but complementary perspectives. The emphasis thr...

  7. On the Path to SunShot. Utility Regulatory and Business Model Reforms for Addressing the Financial Impacts of Distributed Solar on Utilities

    Energy Technology Data Exchange (ETDEWEB)

    Barbose, Galen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Miller, John [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sigrin, Ben [National Renewable Energy Lab. (NREL), Golden, CO (United States); Reiter, Emerson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cory, Karlynn [National Renewable Energy Lab. (NREL), Golden, CO (United States); McLaren, Joyce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Seel, Joachim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Darghouth, Naim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Satchwell, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-05-01

    Net-energy metering (NEM) has helped drive the rapid growth of distributed PV (DPV) but has raised concerns about electricity cost shifts, utility financial losses, and inefficient resource allocation. These concerns have motivated real and proposed reforms to utility regulatory and business models. This report explores the challenges and opportunities associated with such reforms in the context of the U.S. Department of Energy's SunShot Initiative. Most of the reforms to date address NEM concerns by reducing the benefits provided to DPV customers and thus constraining DPV deployment. Eliminating NEM nationwide, by compensating exports of PV electricity at wholesale rather than retail rates, could cut cumulative DPV deployment by 20% in 2050 compared with a continuation of current policies. This would slow the PV cost reductions that arise from larger scale and market certainty. It could also thwart achievement of the SunShot deployment goals even if the initiative's cost targets are achieved. This undesirable prospect is stimulating the development of alternative reform strategies that address concerns about distributed PV compensation without inordinately harming PV economics and growth. These alternatives fall into the categories of facilitating higher-value DPV deployment, broadening customer access to solar, and aligning utility profits and earnings with DPV. Specific strategies include utility ownership and financing of DPV, community solar, distribution network operators, services-driven utilities, performance-based incentives, enhanced utility system planning, pricing structures that incentivize high-value DPV configurations, and decoupling and other ratemaking reforms that reduce regulatory lag. These approaches represent near- and long-term solutions for preserving the legacy of the SunShot Initiative.

  8. Statistical study of network jets observed in the solar transition region: A comparison between coronal holes and quiet sun regions

    CERN Document Server

    Narang, Nancy; Tian, Hui; Banerjee, Dipankar; Cranmer, Steven R; DeLuca, Ed E; McKillop, Sean

    2016-01-01

    Recent IRIS observations have revealed a prevalence of intermittent small-scale jets with apparent speeds of 80 - 250 km s$^{-1}$, emanating from small-scale bright regions inside network boundaries of coronal holes. We find that these network jets appear not only in coronal holes but also in quiet-sun regions. Using IRIS 1330A (C II) slit-jaw images, we extract several parameters of these network jets, e.g. apparent speed, length, lifetime and increase in foot-point brightness. Using several observations, we find that some properties of the jets are very similar but others are obviously different between the quiet sun and coronal holes. For example, our study shows that the coronal-hole jets appear to be faster and longer than those in the quiet sun. This can be directly attributed to a difference in the magnetic configuration of the two regions with open magnetic field lines rooted in coronal holes and magnetic loops often present in quiet sun. We have also detected compact bright loops, likely transition r...

  9. Solar vision Amsterdam. Citizens and businesses go for the sun; Zonvisie Amsterdam. Burgers en bedrijven gaan voor de zon

    Energy Technology Data Exchange (ETDEWEB)

    Stam, T.; Diependaal, F.; Van ' t Hull, C.

    2013-06-15

    In the Solar Vision it is explained how the Amsterdam municipality plans to enable its citizens and businesses to realize their own solar energy project. The Solar Vision is prepared based on input from residents, businesses and institutions [Dutch] In de zonvisie staat hoe de gemeente Amsterdam haar burgers en bedrijven in staat wil stellen om hun eigen zonne-energieproject te realiseren. De zonvisie is mede opgesteld op basis van input van bewoners, bedrijven en instellingen.

  10. STDAC: Solar thermal design assistance center annual report fiscal year 1994

    Science.gov (United States)

    The Solar Thermal Design Assistance Center (STDAC) at Sandia is a resource provided by the DOE Solar Thermal Program. The STDAC's major objective is to accelerate the use of solar thermal systems by providing direct technical assistance to users in industry, government, and foreign countries; cooperating with industry to test, evaluate, and develop renewable energy systems and components; and educating public and private professionals, administrators, and decision makers. This FY94 report highlights the activities and accomplishments of the STDAC. In 1994, the STDAC continued to provide significant direct technical assistance to domestic and international organizations in industry, government, and education, Applying solar thermal technology to solve energy problems is a vital element of direct technical assistance. The STDAC provides information on the status of new, existing, and developing solar technologies; helps users screen applications; predicts the performance of components and systems; and incorporates the experience of Sandia's solar energy personnel and facilities to provide expert guidance. The STDAC directly enhances the US solar industry's ability to successfully bring improved systems to the marketplace. By collaborating with Sandia's Photovoltaic Design Assistance Center and the National Renewable Energy Laboratory the STDAC is able to offer each customer complete service in applying solar thermal technology. At the National Solar Thermal Test Facility the STDAC tests and evaluates new and innovative solar thermal technologies. Evaluations are conducted in dose cooperation with manufacturers, and the results are used to improve the product and/or quantify its performance characteristics. Manufacturers, in turn, benefit from the improved design, economic performance, and operation of their solar thermal technology. The STDAC provides cost sharing and in-kind service to manufacturers in the development and improvement of solar technology.

  11. STDAC: Solar Thermal Design Assistance Center annual report fiscal year 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The Solar Thermal Design Assistance Center (STDAC) at Sandia is a resource provided by the DOE Solar Thermal Program. The STDAC`s major objective is to accelerate the use of solar thermal systems by providing direct technical assistance to users in industry, government, and foreign countries; cooperating with industry to test, evaluate, and develop renewable energy systems and components; and educating public and private professionals, administrators, and decision makers. This FY94 report highlights the activities and accomplishments of the STDAC. In 1994, the STDAC continued to provide significant direct technical assistance to domestic and international organizations in industry, government, and education, Applying solar thermal technology to solve energy problems is a vital element of direct technical assistance. The STDAC provides information on the status of new, existing, and developing solar technologies; helps users screen applications; predicts the performance of components and systems; and incorporates the experience of Sandia`s solar energy personnel and facilities to provide expert guidance. The STDAC directly enhances the US solar industry`s ability to successfully bring improved systems to the marketplace. By collaborating with Sandia`s Photovoltaic Design Assistance Center and the National Renewable Energy Laboratory the STDAC is able to offer each customer complete service in applying solar thermal technology. At the National Solar Thermal Test Facility the STDAC tests and evaluates new and innovative solar thermal technologies. Evaluations are conducted in dose cooperation with manufacturers, and the results are used to improve the product and/or quantify its performance characteristics. Manufacturers, in turn, benefit from the improved design, economic performance, and operation of their solar thermal technology. The STDAC provides cost sharing and in-kind service to manufacturers in the development and improvement of solar technology.

  12. Broadband radio spectral observations of the solar eclipse on 2008-08-01 and its implications on the quiet Sun atmospheric model

    Institute of Scientific and Technical Information of China (English)

    TAN BaoLin; CHEN LinJie; JI GuoShu; YAN YiHua; ZHANG Yin; TAN ChengMin; HUANG Jing; LIU YuYing; FU QiJun; CHEN ZhiJun; LIU Fei

    2009-01-01

    Based on the joint-observations of the radio broadband spectral emissions of the solar eclipse on Au-gust 1, 2008 at Jiuquan (total eclipse) and Huairou (partial eclipse) at the frequencies of 2.00-5.60 GHz (Jiuquan), 2.60-3.80 GHz (Chinese solar broadband radiospectrometer, SBRS/Huairou), and 5.20-7.60 GHz (SBRS/Huairou), the authors assemble a successive series of broadband spectra with a frequency of 2.60-7.60 GHz to observe the solar eclipse synchronously. This is the first attempt to analyze the solar eclipse radio emission under the two telescopes located at different places with broadband frequencies in the periods of total and partial eclipses. With these analyses, the authors made a semiempirical model of the coronal plasma density of the quiet Sun, which can be expressed as n_e≌1.42×10~9(r~(-2)+1.93r~(-5)) (cm~(-3)), in the space range of r=1.039-1.212 R_⊙, and made a comparison with the classic model.

  13. Broadband radio spectral observations of the solar eclipse on 2008-08-01 and its implications on the quiet Sun atmospheric model

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on the joint-observations of the radio broadband spectral emissions of the solar eclipse on August 1, 2008 at Jiuquan (total eclipse) and Huairou (partial eclipse) at the frequencies of 2.00-5.60 GHz (Jiuquan), 2.60-3.80 GHz (Chinese solar broadband radiospectrometer, SBRS/Huairou), and 5.20-7.60 GHz (SBRS/Huairou), the authors assemble a successive series of broadband spectra with a frequency of 2.60-7.60 GHz to observe the solar eclipse synchronously. This is the first attempt to analyze the solar eclipse radio emission under the two telescopes located at different places with broadband frequencies in the periods of total and partial eclipses. With these analyses, the authors made a semiempirical model of the coronal plasma density of the quiet Sun, which can be expressed as ne 1.42×109(r-2+1.93r-5) (cm-3), in the space range of r=1.039-1.212 R , and made a comparison with the classic model.

  14. The Sun's Supergranulation

    CERN Document Server

    Rieutord, Michel

    2010-01-01

    The Sun's supergranulation refers to a physical pattern covering the surface of the quiet Sun with a typical horizontal scale of approximately 30000km. Its most noticeable observable signature is as a fluctuating velocity field whose components are mostly horizontal. Supergranulation was discovered more than fifty years ago, however explaining why and how it originates still represents one of the main challenges of modern solar physics. A lot of work has been devoted to the subject over the years, but observational constraints, conceptual difficulties and numerical limitations have all concurred to prevent a detailed understanding of the supergranulation phenomenon so far. With the advent of 21st century supercomputing resources and the availability of unprecedented high-resolution observations of the Sun, the solar community has now reached a stage at which key progress can be made on this question. A unifying strategy between observations and modeling is more than ever required for this to be possible. The ...

  15. Solar ultraviolet radiation measurements at South African and Reunion Island Coastal Sites: An indicator of public sun protection

    CSIR Research Space (South Africa)

    Wright, CY

    2013-09-01

    Full Text Available Solar ultraviolet radiation (UVR) has the potential to cause biological harm to humans. Intensity of solar UVR at the Earth’s surface depends on several factors, such as total column ozone and cloud cover, and temporal trends are usually dependent...

  16. Relationship of Solar Radio Emission at λ=1.43m and Optical Processes in the Sun

    Science.gov (United States)

    Makandarashvili, Sh.; Oghrapishvili, N.; Japaridze, D.; Maghradze, D.

    2016-09-01

    Radio frequency observations supplement optical studies and in some cases they are the only way of obtaining information on the physical conditions for radio waves and their propagation. Solar radio emission appears in two forms, "quiescent" and "sporadic." Their distinctive features are well known. Solar radio observations at meter wavelengths (λ = 1.43 m, ν = 210 MHz) have been made at the Abastumani Astrophysical Observatory using a solar radio telescope throughout five solar cycles (since 1957). This article is a study of the long-term observations of solar radio bursts and sunspots. It is found that there is a correlation between the amplitudes of the radio bursts, the number of spots, and the regions of the spots.

  17. Skylab Apollo Telescope Mount Spar and Sun End

    Science.gov (United States)

    1971-01-01

    The Apollo Telescope Mount (ATM) was designed and developed by the Marshall Space Flight Center and served as the primary scientific instrument unit aboard Skylab (1973-1979). The ATM contained eight complex astronomical instruments designed to observe the Sun over a wide spectrum from visible light to x-rays. This image depicts the sun end and spar of the ATM flight unit showing individual telescopes. All solar telescopes, the fine Sun sensors, and some auxiliary systems are mounted on the spar, a cruciform lightweight perforated metal mounting panel that divides the canister lengthwise into four equal compartments. The spar assembly was nested inside a cylindrical canister that fit into a complex frame named the rack, and was protected by the solar shield.

  18. Queimaduras e hábitos solares em um grupo de atletas brasileiros Quemaduras y hábitos solares en un grupo de atletas brasileños Sunburns and sun habits in a group of Brazilian athletes

    Directory of Open Access Journals (Sweden)

    Renato Marchiori Bakos

    2006-10-01

    Full Text Available INTRODUÇÃO E OBJETIVOS: As queimaduras solares são consideradas o principal fator de risco ambiental para o melanoma, principalmente quando antes dos 20 anos de idade. Atletas profissionais são, em sua maioria, jovens que se expõem ao sol com bastante intensidade, tanto em suas atividades quanto no lazer, tornando-se um grupo susceptível às queimaduras. O estudo visa avaliar os conhecimentos e hábitos de proteção solar de um grupo de atletas brasileiros. MÉTODOS: Cento e quinze atletas brasileiros, durante os XIV Jogos Pan-Americanos, responderam a um questionário sobre queimaduras solares nos treinamentos e lazer, fototipo, uso de filtros solares (UFS e conhecimento da importância de se proteger do sol (IPS e local da prática (outdoor x indoor. RESULTADOS: A maioria era outdoor (73% e 59% possuíam fototipo claro (I, II ou III. Quanto ao seu local de prática, os outdoor apresentaram índices superiores de queimaduras solares, IPS e UFS durante seus treinamentos, enquanto no lazer os grupos não se diferenciaram. Divididos por fototipo, os grupos de atletas mais claros apresentaram mais queimaduras solares, tanto em treinamentos quanto no lazer. Na análise multivariada para avaliação de risco de queimaduras solares, os fototipos claros e a IPS demonstraram-se estatisticamente significativos. CONCLUSÕES: Esportes realizados ao ar livre geram mais queimaduras solares nos atletas que os praticam. Entretanto, quando em tempo de lazer, atletas outdoor e indoor possuem hábitos solares semelhantes, mostrando que neste momento formam um grupo homogêneo com relação à fotoexposição. Atletas com fototipos claros são mais propensos a queimaduras, tanto no lazer quanto nos treinamentos. As taxas de uso de filtros solares são inferiores ao desejado. É necessário estimular a fotoproteção nos atletas, tanto nas suas atividades desportivas quanto no lazer.INTRODUCCIÓN Y OBJETIVOS: Las quemaduras solares son consideradas el

  19. Transferring the calibration of direct solar irradiance to diffuse-sky radiance measurements for CIMEL Sun-sky radiometers.

    Science.gov (United States)

    Li, Zhengqiang; Blarel, Luc; Podvin, Thierry; Goloub, Philippe; Buis, Jean-Pierre; Morel, Jean-Philippe

    2008-04-01

    Two types of sunphotometric measurement are considered in this study: direct-Sun irradiance and diffuse-sky radiance. Based on CIMEL CE318 Sun-sky radiometer characteristics, we introduce a gain-corrected solid angle that allows interconverting calibration coefficients of these two types of measurement, thus realizing a "vicarious" radiance calibration. The accuracy of the gain-corrected solid angle depends on the number of available historical calibration records. The method is easy to use, provided that at least one laboratory calibration has been made previously. Examples coming from three distinct CE318 versions belonging to the AERONET/PHOTONS network are presented to provide details on the vicarious calibration method and protocols. From the error propagation analysis and the comparison with laboratory results, the uncertainty of the vicarious radiance calibration is shown to be comparable with the laboratory one, e.g., 3%-5%.

  20. Stars resembling the Sun

    Science.gov (United States)

    Cayrel de Strobel, G.

    This review is primarily directed to the question whether photometric solar analogues remain such when subjected to detailed spectroscopic analyses and interpreted with the help of internal stucture models. In other words, whether the physical parameters: mass, chemical composition, age (determining effective temperature and luminosity), chromospheric activity, equatorial rotation, lithium abundance, velocity fields etc., we derive from the spectral analysis of a photometric solar analogue, are really close to those of the Sun. We start from 109 photometric solar analogues extracted from different authors. The stars selected had to satisfy three conditions: i) their colour index (B-V) must be contained in the interval: Δ (B-V) = 0.59-0.69, ii) they must possess a trigonometric parallax, iii) they must have undergone a high resolution detailed spectroscopic analysis. First, this review presents photometric and spectrophotometric researches on solar analogues and recalls the pionneering work on these stars by the late Johannes Hardorp. After a brief discussion on low and high resolution spectroscopic researches, a comparison is made between effective temperatures as obtained, directly, from detailed spectral analyses and those obtained, indirectly, from different photometric relations. An interesting point in this review is the discussion on the tantalilizing value of the (B-V)solar of the Sun, and the presentation of a new reliable value of this index. A short restatement of the kinematic properties of the sample of solar analogues is also made. And, finally, the observational ( T eff, M bol) diagram, obtained with 99 of the initially presented 109 analogues, is compared to a theoretical ( T eff, M bol) diagram. This latter has been constructed with a grid of internal structure models for which, (very important for this investigation), the Sun was used as gauge. In analysing the position, with respect to the Sun, of each star we hoped to find a certain number of

  1. Solar Probe Cup - Demonstrated Laboratory Performance

    Science.gov (United States)

    Case, A. W.; Kasper, J. C.; Korreck, K. E.; Stevens, M. L.; Larson, D. E.; Wright, K. H., Jr.; Gallagher, D. L.; Whittlesey, P. L.

    2016-12-01

    The Solar Probe Cup (SPC) is a Faraday Cup instrument that will fly on the Solar Probe Plus (SPP) spacecraft, orbiting the Sun as close as 9.86 solar radii from the center of the Sun. The SPC instrument is designed to measure the thermal solar wind plasma (protons, alphas, and electrons) that will be encountered throughout its close encounter with the Sun. Due to the solar wind flow being primarily radial, the SPC instrument is pointed directly at the Sun, resulting in an extreme thermal environment that must be tolerated throughout the primary data collection phase. Laboratory testing has been performed over the past 6 months to demonstrate the instrument's performance relative to its requirements, and to characterize the measurements over the expected thermal range. This presentation will demonstrate the performance of the instrument as measured in the lab, describe the operational configurations planned for flight, and discuss the data products that will be created.

  2. On the Path to SunShot - The Role of Advancements in Solar Photovoltaic Efficiency, Reliability, and Costs

    Energy Technology Data Exchange (ETDEWEB)

    Woodhouse, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jones-Albertus, Rebecca [Dept. of Energy (DOE), Washington DC (United States); Feldman, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Fu, Ran [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, Kelsey [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chung, Donald [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jordan, Dirk [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurtz, Sarah [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Although tremendous progress has been made in reducing the cost of PV systems, additional LCOE reductions of 40%–50% between 2015 and 2020 will be required to reach the SunShot Initiative’s targets (see Woodhouse et al. 2016). Understanding the tradeoffs between installed prices and other PV system characteristics—such as module efficiency, module degradation rate, and system lifetime—are vital. For example, with 29%-efficient modules and high reliability (a 50-year lifetime and a 0.2%/year module degradation rate), a residential PV system could achieve the SunShot LCOE goal with modules priced at almost $1.20/W. But change the lifetime to 10 years and the degradation rate to 2%/year, and the system would need those very high-efficiency modules at zero cost to achieve the same LCOE. Although these examples are extreme, they serve to illustrate the wide range of technological combinations that could help drive PV toward the LCOE goals. SunShot’s PV roadmaps illustrate specific potential pathways to the target cost reductions.

  3. Renewable Resources: a national catalog of model projects. Volume 1. Northeast Solar Energy Center Region

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-07-01

    This compilation of diverse conservation and renewable energy projects across the United States was prepared through the enthusiastic participation of solar and alternate energy groups from every state and region. Compiled and edited by the Center for Renewable Resources, these projects reflect many levels of innovation and technical expertise. In many cases, a critique analysis is presented of how projects performed and of the institutional conditions associated with their success or failure. Some 2000 projects are included in this compilation; most have worked, some have not. Information about all is presented to aid learning from these experiences. The four volumes in this set are arranged in state sections by geographic region, coinciding with the four Regional Solar Energy Centers. The table of contents is organized by project category so that maximum cross-referencing may be obtained. This volume includes information on the Northeast Solar Energy Center Region. (WHK).

  4. Renewable Resources: a national catalog of model projects. Volume 3. Southern Solar Energy Center Region

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-07-01

    This compilation of diverse conservation and renewable energy projects across the United States was prepared through the enthusiastic participation of solar and alternate energy groups from every state and region. Compiled and edited by the Center for Renewable Resources, these projects reflect many levels of innovation and technical expertise. In many cases, a critique analysis is presented of how projects performed and of the institutional conditions associated with their success or failure. Some 2000 projects are included in this compilation; most have worked, some have not. Information about all is presented to aid learning from these experiences. The four volumes in this set are arranged in state sections by geographic region, coinciding with the four Regional Solar Energy Centers. The table of contents is organized by project category so that maximum cross-referencing may be obtained. This volume includes information on the Southern Solar Energy Center Region. (WHK)

  5. On the Path to SunShot - Emerging Issues and Challenges in Integrating High Levels of Solar into the Electrical Generation and Transmission System

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Clark, Kara [National Renewable Energy Lab. (NREL), Golden, CO (United States); O' Connell, Matt [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Increasing the use of grid-flexibility options (improved grid management, demand response, and energy storage) could enable 25% or higher penetration of PV at low costs (see Denholm et al. 2016). Considering the large-scale integration of solar into electric-power systems complicates the calculation of the value of solar. In fact a comprehensive examination reveals that the value of solar technologies—or any other power-system technology or operating strategy—can only be understood in the context of the generation system as a whole. This is well illustrated by analysis of curtailment at high PV penetrations within the bulk power and transmission systems. As the deployment of PV increases, it is possible that during some sunny midday periods due to limited flexibility of conventional generators, system operators would need to reduce (curtail) PV output in order to maintain the crucial balance between electric supply and demand. As a result, PV’s value and cost competitiveness would degrade. For example, for utility-scale PV with a baseline SunShot LCOE of 6¢/kWh, increasing the annual energy demand met by solar energy from 10% to 20% would increase the marginal LCOE of PV from 6¢/kWh to almost 11¢/kWh in a California grid system with limited flexibility. However, this loss of value could be stemmed by increasing system flexibility via enhanced control of variable-generation resources, added energy storage, and the ability to motivate more electricity consumers to shift consumption to lower-demand periods. The combination of these measures would minimize solar curtailment and keep PV cost-competitive at penetrations at least as high as 25%. Efficient deployment of the grid-flexibility options needed to maintain solar’s value will require various innovations, from the development of communication, control, and energy storage technologies to the implementation of new market rules and operating procedures.

  6. The Solar Thermal Design Assistance Center report of its activities and accomplishments in Fiscal Year 1993

    Energy Technology Data Exchange (ETDEWEB)

    Menicucci, D.F.

    1994-03-01

    The Solar Thermal Design Assistance Center (STDAC) at Sandia National Laboratories is a resource provided by the US Department of Energy`s Solar Thermal Program. Its major objectives are to accelerate the use of solar thermal systems through (a) direct technical assistance to users, (b) cooperative test, evaluation, and development efforts with private industry, and (c) educational outreach activities. This report outlines the major activities and accomplishments of the STDAC in Fiscal Year 1993. The report also contains a comprehensive list of persons who contacted the STDAC by telephone for information or technical consulting.

  7. Evolution of The Proton Velocity Distribution due to Stochastic Heating in the Near-Sun Solar Wind

    CERN Document Server

    Klein, Kristopher G

    2016-01-01

    We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfv\\'en-wave turbulence under the assumption that $\\beta$ is small. We apply our analysis to protons undergoing stochastic heating in the supersonic fast solar wind and obtain proton distributions at heliocentric distances ranging from 4 to 30 solar radii. We find that the proton distribution develops non-Gaussian structure with a flat core and steep tail. For $r >5 \\ R_{\\rm S}$, the proton distribution is well approximated by a modified Moyal distribution. Comparisons with future measurements from \\emph{Solar Probe Plus} could be used to test whether stochastic heating is occurring in the solar-wind acceleration region.

  8. Raising the One-Sun Conversion Efficiency of III-V/Si Solar Cells to 32.8% for Two Junctions and 35.9% for Three Junctions

    Energy Technology Data Exchange (ETDEWEB)

    Tamboli, Adele C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Geisz, John F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Young, David L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Steiner, Myles A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Horowitz, Kelsey A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Woodhouse, Michael A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schnabel, Manuel [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Remo, Timothy W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Essig, Stephanie [Ecole Polytechnique Federale de Lausanne (EPFL); Allebe, Christophe [CSEM PV-Center; Barroud, Lorris [CSEM PV-Center; Descoeudres, Antoine [CSEM PV-Center; Despeisse, Matthieu [CSEM PV-Center; Ballif, Christophe [CSEM PV-Center; Ward, J. Scott [Formerly NREL

    2017-08-25

    Today's dominant photovoltaic technologies rely on single-junction devices, which are approaching their practical efficiency limit of 25-27%. Therefore, researchers are increasingly turning to multi-junction devices, which consist of two or more stacked subcells, each absorbing a different part of the solar spectrum. Here, we show that dual-junction III-V//Sidevices with mechanically stacked, independently operated III-V and Si cells reach cumulative one-sun efficiencies up to 32.8%. Efficiencies up to 35.9% were achieved when combining a GaInP/GaAs dual-junction cell with a Si single-junction cell. These efficiencies exceed both the theoretical 29.4% efficiency limit of conventional Si technology and the efficiency of the record III-V dual-junction device (32.6%), highlighting the potential of Si-based multi-junction solar cells. However, techno-economic analysis reveals an order-of-magnitude disparity between the costs for III-V//Si tandem cells and conventional Si solar cells, which can be reduced if research advances in low-cost III-V growth techniques and new substrate materials are successful.

  9. Origin of the p-process radionuclides 92Nb and 146Sm in the early Solar System and inferences on the birth of the Sun

    CERN Document Server

    Lugaro, Maria; Ott, Ulrich; Zuber, Kai; Travaglio, Claudia; Gyurky, Gyorgy; Fulop, Zsolt

    2016-01-01

    The abundances of 92Nb and 146Sm in the early Solar System are determined from meteoritic analysis and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion of white dwarfs with mass above the Chandrasekhar limit is in agreement with the abundance of 53Mn, another radionuclide present in the early Solar System and produced in the same events. A consistent solution for 92Nb and 53Mn cannot be found within the current uncertainties and requires that the 92Nb/92Mo ratio in the early Solar System is at least 50% lower than the current nominal value, which is outside its present error bars. A different solution is to invoke another production site for 92Nb, which we find in the alpha-rich freezeout during core-collapse supernovae from massive stars. Whichever scenario we consider, we find that a relatively long time interval of at least ~10 Myr must have elapsed from when the star-forming region where the Sun was born was i...

  10. Understanding New Elements of Acceleration and Transport of Solar Energetic Particles (SEPs) from the Sun to the Earth

    Science.gov (United States)

    2012-01-13

    Longitudinal Separations...............................6 6. RHESSI Dynamic Plots of the 2003 May 29 SHH Hard X-ray Burst...The Kiplinger effect is an observed association of solar energetic (E > 10 MeV) particle (SEP) events with a “soft-hard-harder" ( SHH ) spectral...and then examined recent evidence from the Ramaty High-Energy Solar Spectrometric Imager (RHESSI) supporting the association of SHH HXR flares with

  11. To live with the sun - utilization of solar energy for the Talhof. Mit der Sonne leben - Solarstrom fuer den Talhof

    Energy Technology Data Exchange (ETDEWEB)

    Sauer, H.D.

    1990-06-01

    Technical progress sometimes takes place at remote places. Away from the Bundesstrasse 27 which goes from Rottweil via the Swabian Mountains to Tubingen a lovingly renovated old farmhouse is located in a romantic meadow near Schoemberg. Since the middle of last year 90% of its electricity demand is covered with solar power. The project has been presented to the public by the Fraunhofer-Institut fuer Solare Energiesysteme Freiburg at the 18.th of May. (orig.).

  12. SFC - The Solar activity and geomagnetic indices Forecast Center

    Science.gov (United States)

    Valette, Jean-Jacques; Nicolas, Fuller; Philippe, Yaya

    CLS which operates SFC still maintains close collaboration with scientific laboratories or the Space Agencies in order to improve the prediction service performances and to extend the range of its applications. SFC also participates to ISES activities as an Associate Regional Warning Center.

  13. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  14. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  15. Improving solar wind persistence forecasts: Removing transient space weather events, and using observations away from the Sun-Earth line

    Science.gov (United States)

    Kohutova, Petra; Bocquet, François-Xavier; Henley, Edmund M.; Owens, Matthew J.

    2016-10-01

    This study demonstrates two significant ways of improving persistence forecasts of the solar wind, which exploit the relatively unchanging nature of the ambient solar wind to provide 27 day forecasts, when using data from the Lagrangian L1 point. Such forecasts are useful as a prediction tool for the ambient wind, and for benchmarking of solar wind models. We show that solar wind persistence forecasts can be improved by removing transient solar wind features such as coronal mass ejections (CMEs). Using CME indicators to automatically identify CME-contaminated periods in ACE data from 1998 to 2011, and replacing these with solar wind from a previous synodic rotation, persistence forecasts improve (relative to a baseline): skill scores for Bz, a crucial parameter for determining solar wind geoeffectiveness, improve by 7.7 percentage points when using a proton temperature-based indicator with good operational potential. We also show that persistence forecasts can be improved by using measurements away from L1, to reduce the requirement on coronal stability for an entire synodic period, at the cost of reduced lead time. Using STEREO-B data from 2007 to 2013 to create such a reduced lead time persistence forecast, we show that Bz skill scores improve by 17.1 percentage points relative to ACE. Finally, we report on implications for persistence forecasts from any future missions to the L5 Lagrangian point and on the successful operational implementation (in spring 2015) of the normal (ACE-based) and reduced lead time (STEREO-based) persistence forecasts in the Met Office's Space Weather Operations Centre, as well as plans for future improvements.

  16. The Sun, Mercury, and Venus

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    The Messenger mission to Mercury opened a new window into the inner solar system. In 2008, this mission began a number of years of flybys, culminating in an orbital insertion around Mercury and producing unparalleled observations about this mysterious innermost planet. Mercury orbits so close to the Sun, from the point of view of Earth, that seeing it from the Earth against the Sun's glare is a great challenge. At the same time, the huge gravitational force of the Sun makes it a challenge to put a mission on Mercury without losing it into the Sun. Now, with heightened understanding of Mercury,

  17. On the Path to SunShot. Emerging Issues and Challenges in Integrating Solar with the Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    Palmintier, Bryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Broderick, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mather, Barry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Coddington, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baker, Kyri [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ding, Fei [National Renewable Energy Lab. (NREL), Golden, CO (United States); Reno, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lave, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bharatkumar, Ashwini [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2016-05-01

    This report analyzes distribution-integration challenges, solutions, and research needs in the context of distributed generation from PV (DGPV) deployment to date and the much higher levels of deployment expected with achievement of the U.S. Department of Energy's SunShot targets. Recent analyses have improved estimates of the DGPV hosting capacities of distribution systems. This report uses these results to statistically estimate the minimum DGPV hosting capacity for the contiguous United States using traditional inverters of approximately 170 GW without distribution system modifications. This hosting capacity roughly doubles if advanced inverters are used to manage local voltage and additional minor, low-cost changes could further increase these levels substantially. Key to achieving these deployment levels at minimum cost is siting DGPV based on local hosting capacities, suggesting opportunities for regulatory, incentive, and interconnection innovation. Already, pre-computed hosting capacity is beginning to expedite DGPV interconnection requests and installations in select regions; however, realizing SunShot-scale deployment will require further improvements to DGPV interconnection processes, standards and codes, and compensation mechanisms so they embrace the contributions of DGPV to system-wide operations. SunShot-scale DGPV deployment will also require unprecedented coordination of the distribution and transmission systems. This includes harnessing DGPV's ability to relieve congestion and reduce system losses by generating closer to loads; minimizing system operating costs and reserve deployments through improved DGPV visibility; developing communication and control architectures that incorporate DGPV into system operations; providing frequency response, transient stability, and synthesized inertia with DGPV in the event of large-scale system disturbances; and potentially managing reactive power requirements due to large-scale deployment of advanced

  18. Evolution of the solar activity over time and effects on planetary atmospheres. II. kappa^1 Ceti, an analog of the Sun when life arose on Earth

    CERN Document Server

    Ribas, I; Ferreira, L D; Hebrard, E; Selsis, F; Catalan, S; Garces, A; Nascimento, J D do; de Medeiros, J R

    2010-01-01

    The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar radiative input is needed. We present an investigation of the atmospheric parameters, state of evolution and high-energy fluxes of the nearby star kap^1 Cet, previously thought to have properties resembling those of the early Sun. Atmospheric parameters were derived from the excitation/ionization equilibrium of Fe I and Fe II, profile fitting of Halpha and the spectral energy distribution. The UV irradiance was derived from FUSE and HST data, and the absolute chromospheric flux from the Halpha line core. From careful spectral analysis and the comparison of different methods we propose for kap^1 Cet the following atmospheric parameters: Teff = 5665+/-30 K (Halpha profil...

  19. Piece of the sun

    CERN Document Server

    Wayne, Teddy

    2015-01-01

    Our rapidly industrialising world has an insatiable hunger for energy, and conventional sources are struggling to meet demand. Oil is running out, coal is damaging our climate, many nations are abandoning nuclear, yet solar, wind and water will never be a complete replacement. The solution, says Daniel Clery in this deeply researched and revelatory book, is to be found in the original energy source: the Sun itself. There, at its centre, the fusion of 630 million tonnes of hydrogen every second generates an unfathomable amount of energy. By replicating even a tiny piece of the Sun's power

  20. Submission of Final Scientific/Technical Report [Solar Avoided Cost Solution: SunShot 6 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Danziger, Eric

    2014-01-29

    The core objectives of this project were two separate but integrated products, collectively providing game-changing Avoided Cost capabilities. • The first was a kit of avoided cost tools and data that any solar provider can use a-lacarte or as a whole. It’s open and easily accessible nature allows the rapid and accurate calculation of avoided cost in whatever context and software that make sense (“Typical and Avoided Cost Tools”). This kit includes a dataset of typical energy rates, costs and usage that can be used for solar prospecting, lead generation and any situation where data about an opportunity is missing or imperfect. • The second is a web application and related APIs specifically built for solar providers to radically streamline their lead-to-sale process (“Solar Provider Module”). The typical and Avoided Cost tools are built directly into this, and allow for solar providers to track their opportunities, collaborate with their installers and financiers, and close more sales faster.

  1. Sun-Earth Days

    Science.gov (United States)

    Thieman, J.; Ng, C.; Lewis, E.; Cline, T.

    2010-08-01

    Sun-Earth Day is a well-coordinated series of programs, resources and events under a unique yearly theme highlighting the fundamentals of heliophysics research and missions. A menu of activities, conducted throughout the year, inspire and educate participants. Sun-Earth Day itself can vary in date, but usually is identified by a celebration on or near the spring equinox. Through the Sun-Earth Day framework we have been able to offer a series of coordinated events that promote and highlight the Sun, its connection to Earth and the other planets. Sun-Earth Day events are hosted by educators, museums, amateur astronomers and scientists and occur at schools, community groups, parks, planetaria and science centers around the globe. Sun-Earth Day raises the awareness and knowledge of formal and informal education audiences concerning space weather and heliophysics. By building on the success of Sun-Earth Day yearly celebrations, we seek to affect people of all backgrounds and ages with the wonders of heliophysics science, discovery, and exploration in ways that are both tangible and meaningful to their lives.

  2. Finding the lost siblings of the Sun

    Science.gov (United States)

    Liu, Cheng; Feltzing, Sofia; Ruchti, Gregory

    2014-01-01

    We have performed a spectral analysis on 18 stars solar sibling candidate. We found that only one one of the candidateshas solar metallicity and at the same time might have an age comparable to that of the Sun.

  3. Hysteresis Effect in the Activity Indices of the Atmospheres of the Sun and Solar-Type Stars During the Rising and Falling Phases of Cycles

    Science.gov (United States)

    Bruevich, E. A.; Yakunina, G. V.

    2016-09-01

    The hysteresis effect that shows up as a nonunique relationship among the emissions from the photosphere, chromosphere, and corona during the rising and falling phases of solar and stellar activity is analyzed. The following solar indices are analyzed and compared in different phases of the cycle: the radiative flux in the hydrogen Lyman alpha line FLα, radio emission at 10.7 cm F10.7, the sunspot number SSN, the radiative flux in the 530.0 nm green coronal line F530.3, the solar constant TSI, and the relative flux ratio c/w (ratio of the fluxes in the center and in the wings) for the 280 nm Mg II line. In stars with cycles, a hysteresis effect is observed between the CaII chromospheric S-activity index for stars in the Mount Wilson HK project and the photospheric flux Fph for these stars.

  4. Petascale Computing for Ground-Based Solar Physics with the DKIST Data Center

    Science.gov (United States)

    Berukoff, Steven J.; Hays, Tony; Reardon, Kevin P.; Spiess, DJ; Watson, Fraser; Wiant, Scott

    2016-05-01

    When construction is complete in 2019, the Daniel K. Inouye Solar Telescope will be the most-capable large aperture, high-resolution, multi-instrument solar physics facility in the world. The telescope is designed as a four-meter off-axis Gregorian, with a rotating Coude laboratory designed to simultaneously house and support five first-light imaging and spectropolarimetric instruments. At current design, the facility and its instruments will generate data volumes of 3 PB per year, and produce 107-109 metadata elements.The DKIST Data Center is being designed to store, curate, and process this flood of information, while providing association of science data and metadata to its acquisition and processing provenance. The Data Center will produce quality-controlled calibrated data sets, and make them available freely and openly through modern search interfaces and APIs. Documented software and algorithms will also be made available through community repositories like Github for further collaboration and improvement.We discuss the current design and approach of the DKIST Data Center, describing the development cycle, early technology analysis and prototyping, and the roadmap ahead. We discuss our iterative development approach, the underappreciated challenges of calibrating ground-based solar data, the crucial integration of the Data Center within the larger Operations lifecycle, and how software and hardware support, intelligently deployed, will enable high-caliber solar physics research and community growth for the DKIST's 40-year lifespan.

  5. Catching some Sun : Probing the solar wind with cometary X-ray and far-ultraviolet emission

    NARCIS (Netherlands)

    Bodewits, D; Juhasz, Z; Hoekstra, R; Tielens, AGGM

    2004-01-01

    Strong X-ray and far-ultraviolet emission from comets is the direct result of charge exchange reactions of solar wind ions with the neutral coma of comets. Here we report experimental state-selective cross sections of electron capture and use these to predict cometary line emission. Our results show

  6. Catching some Sun : Probing the solar wind with cometary X-ray and far-ultraviolet emission

    NARCIS (Netherlands)

    Bodewits, D; Juhasz, Z; Hoekstra, R; Tielens, AGGM

    2004-01-01

    Strong X-ray and far-ultraviolet emission from comets is the direct result of charge exchange reactions of solar wind ions with the neutral coma of comets. Here we report experimental state-selective cross sections of electron capture and use these to predict cometary line emission. Our results show

  7. Synoptic and fast events on the sun according to observations at the center and wings of the Ca II K line at the Kislovodsk Mountain station patrol telescope

    Science.gov (United States)

    Tlatov, A. G.; Dormidontov, D. V.; Kirpichev, R. V.; Pashchenko, M. P.; Shramko, A. D.

    2015-12-01

    Observations performed at the solar telescope-spectroheliograph, which has continuously automatically operated at MAS MAO RAS, were analyzed. Measurements of the activity index in the Ca II K line, which were performed according to the program of synoptic observations, are presented. The development of the solar flares observed at the center and on the wings of the Ca II K line was compared with observations in the X-ray and radio bands. It was shown that the time variations in the intensity in the 1-8 Å range according to the Geostationary Orbiting Environmental Satellites' (GOES) data and in the Ca II K line are close to each other and that the total X-ray flux and Ca II K intensity amplitude substantially correlate during the entire flare.

  8. Solar heating system installed at Blakedale Professional Center, Greenwood, South Carolina

    Science.gov (United States)

    1980-01-01

    Information on the solar heating system installed at the Blakedale Professional Center, in Greenwood, South Carolina is presented. The information consists of site and building description, solar system description, performance evaluation, system problems and installation drawings. The solar system was designed to provide approximately 85 percent of the building's heating requirements. The system was installed concurrently with building construction and heats 4,440 square feet of the building. There are 954 square feet of liquid flat plate collectors that are proof-mounted and have a drain-down system to protect the collectors from freezing. A 5,000 gallon steel, polyurethane insulated tank buried underground provides storage. The system was fully instrumented for performance evaluation and integrated into the National Solar Data Network.

  9. Solar Energy Technician/Installer

    Science.gov (United States)

    Moore, Pam

    2007-01-01

    Solar power (also known as solar energy) is solar radiation emitted from the sun. Large panels that absorb the sun's energy as the sun beats down on them gather solar power. The energy in the rays can be used for heat (solar thermal energy) or converted to electricity (photovoltaic energy). Each solar energy project, from conception to…

  10. Solar Energy Technician/Installer

    Science.gov (United States)

    Moore, Pam

    2007-01-01

    Solar power (also known as solar energy) is solar radiation emitted from the sun. Large panels that absorb the sun's energy as the sun beats down on them gather solar power. The energy in the rays can be used for heat (solar thermal energy) or converted to electricity (photovoltaic energy). Each solar energy project, from conception to…

  11. [Research on absolute calibration of sun channel of sun photometer using laser raster scanning method].

    Science.gov (United States)

    Xu, Wen-Bin; Li, Jian-Jun; Zheng, Xiao-Bing

    2013-01-01

    In the present paper, a new calibration method of absolute spectral irradiance responsivity of sun channel of sun photometer was developed. A tunable laser was used as source and a standard tranfer detector, calibrated against cryogenic absolute radiometer, was used to measure laser beam power. By raster scanning of a single collimated laser beam to generate the uniform irradiance field at the plane of effective aperture stop of sun photometer, the absolute irradiance responsivity of center wavelength of the 870 nm unpolarized sun channels of sun photometer was obtained accurately. The relative spectral irradiance responsivity of corresponding channel was obtained by using lamp-monochromator system and then used to acquire the absolute spectral irradiance responsivity in the laboratory. On the basis of the above results, the top-of-the-atmosphere responsive constant V0 was obtained by integration with extraterrestrial solar spectral irradiance data. Comparing the calibration result with that from GSFC, NASA in 2009, the difference is only 3.75%. In the last, the uncertainties of calibration were evaluated and reached to 2.06%. The principle feasibility of the new method was validated.

  12. Sun-Earth Day - Teaching Heliophysics Through Education Technology

    Science.gov (United States)

    Thieman, J.; Cline, T.; Lewis, E.

    2010-01-01

    Sun-Earth Day (SED) is an Education and Outreach program supported by the U.S, National Aeronautics and Space Administration (NASA). The intent of the program is to teach students and the general public about Heliophysics (the science of the study of the Sun, how it varies, and how solar dynamics affect the rest of the solar system, especially the Earth). The program was begun ten years ago. Each year since that time a particular day has been designated as "Sun-Earth Day ,,. Usually the day of the spring equinox (March 20 or 21) is Sun-Earth Day, but other days have been used as well. Each year a theme is chosen relating to Heliophysics and events reflecting that theme are planned not only for Sun-Earth Day, but for the entire year. From the very beginning educational technology was emphasized in the events in order to effectively reach wide audiences with the SED message. The main approach has been to have a "webcast" related to each year's theme, often from a location that supports the theme as well. For example, a webcast took place from the Mayan pyramids at Chichen Itza, Mexico to highlight the theme of "Ancient Observatories, Timeless Knowledge". Webcasts were not the only technology employed, however. Many of the themes centered on the dynamic nature of the Sun and the effects that solar storms can have on interplanetary space and in our day-to-day life on Earth. Activities for tracking when solar storms happen and how they affect the Earth were developed and brought together in an educational package called Space Weather Action Centers. This project is explained in more detail in another presentation in this session being given by Norma Teresinha Oliveira Reis. Recent Sun-Earth Days have utilized "social networking" technologies to reach widespread groups on the internet. Podcasts, Vodcasts, Facebook, Twitter, and Second Life are the types of network technologies being employed now. The NASA Distance learning Network is another method for bringing Sun

  13. 76 FR 32188 - Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2011-06-03

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Hatch Solar Energy Center 1, LLC; Supplemental Notice That Initial... notice in the above-referenced proceeding of Hatch Solar Energy Center 1, LLC's application for...

  14. Sun meter

    Science.gov (United States)

    Younskevicius, Robert E.

    1978-01-01

    A simple, inexpensive device for measuring the radiation energy of the sun impinging on the device. The measurement of the energy over an extended period of time is accomplished without moving parts or tracking mechanisms.

  15. The Liquid Metallic Hydrogen Model of the Sun and the Solar Atmosphere VIII. "Futile" Processes in the Chromosphere (Letters to Progress in Physics

    Directory of Open Access Journals (Sweden)

    Robitaille L.

    2014-01-01

    Full Text Available In the liquid metallic hydrogen solar model (LMHSM, the chr omosphere is the site of hydrogen condensation (P.M. Robitaille. The Liquid Metall ic Hydrogen Model of the Sun and the Solar Atmosphere IV. On the Nature of the Chromosp here. Progr. Phys. , 2013, v. 3, L15–L21. Line emission is associated with the di ssipation of energy from condensed hydrogen structures, CHS. Previously considere d reactions resulted in hy- drogen atom or cluster addition to the site of condensation. In this work, an additional mechanism is presented, wherein atomic or molecular specie s interact with CHS, but do not deposit hydrogen. These reactions channel heat away f rom CHS, enabling them to cool even more rapidly. As a result, this new class of proce sses could complement true hydrogen condensation reactions by providing an auxil iary mechanism for the re- moval of heat. Such ‘futile’ reactions lead to the formation of activated atoms, ions, or molecules and might contribute to line emission from such sp ecies. Evidence that com- plimentary ‘futile’ reactions might be important in the chr omosphere can be extracted from lineshape analysis.

  16. Far-UV Emissions of the Sun in Time: Probing Solar Magnetic Activity and Effects on Evolution of Paleo-Planetary Atmospheres

    CERN Document Server

    Guinan, E F; Harper, G M; Guinan, Edward F.; Ribas, Ignasi; Harper, Graham M.

    2003-01-01

    We present and analyze FUSE observations of six solar analogs. These are single, main-sequence G0-5 strs selected as proxies for the Sun at several stages of its main-sequence lifetime. The emission features in the FUSE 920-1180 A wavelength range allow for a critical probe of the hot plasma over three decades in temperature. Using the flux ratio CIII 1176/977 as diagnostics, we investigate the dependence of the electron pressure of the transition region as a function of the rotation period, age and magnetic activity. The results from these solar proxies indicate that the electron pressure of the stellar ~10^5-K plasma decreases by a factor of about 70 between the young, fast-rotating magnetically active star and the old, slow-rotating inactive star. Also, the observations indicate that the average surface fluxes of emission features strongly decrease with increasing stellar age and longer rotation period. The emission flux evolution with age or rotation period is well fitted by power laws, which become steep...

  17. On the Path to SunShot - Utility Regulatory Business Model Reforms forAddressing the Financial Impacts of Distributed Solar on Utilities

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-05-01

    Net-energy metering (NEM) with volumetric retail electricity pricing has enabled rapid proliferation of distributed photovoltaics (DPV) in the United States. However, this transformation is raising concerns about the potential for higher electricity rates and cost-shifting to non-solar customers, reduced utility shareholder profitability, reduced utility earnings opportunities, and inefficient resource allocation. Although DPV deployment in most utility territories remains too low to produce significant impacts, these concerns have motivated real and proposed reforms to utility regulatory and business models, with profound implications for future DPV deployment. This report explores the challenges and opportunities associated with such reforms in the context of the U.S. Department of Energy’s SunShot Initiative. As such, the report focuses on a subset of a broader range of reforms underway in the electric utility sector. Drawing on original analysis and existing literature, we analyze the significance of DPV’s financial impacts on utilities and non-solar ratepayers under current NEM rules and rate designs, the projected effects of proposed NEM and rate reforms on DPV deployment, and alternative reforms that could address utility and ratepayer concerns while supporting continued DPV growth. We categorize reforms into one or more of four conceptual strategies. Understanding how specific reforms map onto these general strategies can help decision makers identify and prioritize options for addressing specific DPV concerns that balance stakeholder interests.

  18. Solar panel sun-tracking system based on ARM%基于ARM920T的太阳能电池板自动追光系统

    Institute of Scientific and Technical Information of China (English)

    郭文川; 周超超; 刘兴林; 夏田俊

    2012-01-01

    An automatic solar panel light-tracking system based on ARM9 platform was designed to improve the efficiency of solar panels. S3C2440 was used as the controller of the system. Based on the current outputs of the 2D positional sensitive detector (PSD), the directions and angels at which the horizontal and vertical axes should rotated, respectively, were calculated. Two step motors were used to control the two-axis system to trace sun position automatically. Running test shows that the system is stable and reliable, and it has good application prospect.%为了提高太阳能电池板的工作效率,设计了一种基于ARM920T平台的太阳能电池板自动追光系统.系统以ARM920T内核S3C2440处理器为控制器,根据二维光位置敏感探测器PSD的电流输出量确定电池板绕竖直轴和水平轴转动的方向和角度,进而由2个步进电机驱动双轴跟踪系统,以达到自动追光的目的.经测试表明,该系统运行稳定、可靠,具有良好的应用前景.

  19. Design of a Solar Tracking System Using the Brightest Region in the Sky Image Sensor.

    Science.gov (United States)

    Wei, Ching-Chuan; Song, Yu-Chang; Chang, Chia-Chi; Lin, Chuan-Bi

    2016-11-25

    Solar energy is certainly an energy source worth exploring and utilizing because of the environmental protection it offers. However, the conversion efficiency of solar energy is still low. If the photovoltaic panel perpendicularly tracks the sun, the solar energy conversion efficiency will be improved. In this article, we propose an innovative method to track the sun using an image sensor. In our method, it is logical to assume the points of the brightest region in the sky image representing the location of the sun. Then, the center of the brightest region is assumed to be the solar-center, and is mathematically calculated using an embedded processor (Raspberry Pi). Finally, the location information on the sun center is sent to the embedded processor to control two servo motors that are capable of moving both horizontally and vertically to track the sun. In comparison with the existing sun tracking methods using image sensors, such as the Hough transform method, our method based on the brightest region in the sky image remains accurate under conditions such as a sunny day and building shelter. The practical sun tracking system using our method was implemented and tested. The results reveal that the system successfully captured the real sun center in most weather conditions, and the servo motor system was able to direct the photovoltaic panel perpendicularly to the sun center. In addition, our system can be easily and practically integrated, and can operate in real-time.

  20. Design of a Solar Tracking System Using the Brightest Region in the Sky Image Sensor

    Directory of Open Access Journals (Sweden)

    Ching-Chuan Wei

    2016-11-01

    Full Text Available Solar energy is certainly an energy source worth exploring and utilizing because of the environmental protection it offers. However, the conversion efficiency of solar energy is still low. If the photovoltaic panel perpendicularly tracks the sun, the solar energy conversion efficiency will be improved. In this article, we propose an innovative method to track the sun using an image sensor. In our method, it is logical to assume the points of the brightest region in the sky image representing the location of the sun. Then, the center of the brightest region is assumed to be the solar-center, and is mathematically calculated using an embedded processor (Raspberry Pi. Finally, the location information on the sun center is sent to the embedded processor to control two servo motors that are capable of moving both horizontally and vertically to track the sun. In comparison with the existing sun tracking methods using image sensors, such as the Hough transform method, our method based on the brightest region in the sky image remains accurate under conditions such as a sunny day and building shelter. The practical sun tracking system using our method was implemented and tested. The results reveal that the system successfully captured the real sun center in most weather conditions, and the servo motor system was able to direct the photovoltaic panel perpendicularly to the sun center. In addition, our system can be easily and practically integrated, and can operate in real-time.

  1. High-efficiency one-sun photovoltaic module demonstration using solar-grade CZ silicon. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gee, J.M.

    1996-10-01

    This work was performed jointly by Sandia National Laboratories (Albuquerque, NM) and Siemens Solar Industries (Camarillo, CA) under a Cooperative Research and Development Agreement (CRADA 1248). The work covers the period May 1994 to March 1996. The purpose of the work was to explore the performance potential of commercial, photovoltaic-grade Czochralski (Cz) silicon, and to demonstrate this potential through fabrication of high-efficiency cells and a module. Fabrication of the module was omitted in order to pursue further development of advanced device structures. The work included investigation of response of the material to various fabrication processes, development of advanced cell structures using the commercial material, and investigation of the stability of Cz silicon solar cells. Some important achievements of this work include the following: post-diffusion oxidations were found to be a possible source of material contamination; bulk lifetimes around 75 pts were achieved; efficiencies of 17.6% and 15.7% were achieved for large-area cells using advanced cell structures (back-surface fields and emitter wrap-through); and preliminary investigations into photodegradation in Cz silicon solar cells found that oxygen thermal donors might be involved. Efficiencies around 20% should be possible with commercial, photovoltaic-grade silicon using properly optimized processes and device structures.

  2. High-efficiency one-sun photovoltaic module demonstration using solar-grade CZ silicon. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gee, J.M.

    1996-10-01

    This work was performed jointly by Sandia National Laboratories (Albuquerque, NM) and Siemens Solar Industries (Camarillo, CA) under a Cooperative Research and Development Agreement (CRADA 1248). The work covers the period May 1994 to March 1996. The purpose of the work was to explore the performance potential of commercial, photovoltaic-grade Czochralski (Cz) silicon, and to demonstrate this potential through fabrication of high-efficiency cells and a module. Fabrication of the module was omitted in order to pursue further development of advanced device structures. The work included investigation of response of the material to various fabrication processes, development of advanced cell structures using the commercial material, and investigation of the stability of Cz silicon solar cells. Some important achievements of this work include the following: post-diffusion oxidations were found to be a possible source of material contamination; bulk lifetimes around 75 pts were achieved; efficiencies of 17.6% and 15.7% were achieved for large-area cells using advanced cell structures (back-surface fields and emitter wrap-through); and preliminary investigations into photodegradation in Cz silicon solar cells found that oxygen thermal donors might be involved. Efficiencies around 20% should be possible with commercial, photovoltaic-grade silicon using properly optimized processes and device structures.

  3. Sun, Earth and Sky

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    This Second Edition of Sun, Earth and Sky updates the popular text by providing comprehensive accounts of the most recent discoveries made by five modern solar spacecraft during the past decade. Their instruments have used sound waves to peer deep into the Sun’s inner regions and measure the temperature of its central nuclear reactor, and extended our gaze far from the visible Sun to record energetic outbursts that threaten Earth. Breakthrough observations with the underground Sudbury Neutrino Observatory are also included, which explain the new physics of ghostly neutrinos and solve the problematic mismatch between the predicted and observed amounts of solar neutrinos. This new edition of Sun, Earth and Sky also describes our recent understanding of how the Sun’s outer atmosphere is heated to a million degrees, and just where the Sun’s continuous winds come from. As humans we are more intimately linked with our life-sustaining Sun than with any other astronomical object, and the new edition therefore p...

  4. Lessons from the Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available In this brief note, the implications of a condensed Sun will be examined. A celestial body composed of liquid metallic hydrogen brings great promise to astronomy, relative to understanding thermal emission and solar structure. At the same time, as an incom- pressible liquid, a condensed Sun calls into question virtually everything which is cur- rently believed with respect to the evolution and nature of the stars. Should the Sun be condensed, then neutron stars and white dwarfs will fail to reach the enormous densities they are currently believed to possess. Much of cosmology also falls into question, as the incompressibility of matter curtails any thought that a primordial atom once existed. Aging stars can no longer collapse and black holes will know no formative mechanism. A condensed Sun also hints that great strides must still be made in understanding the nature of liquids. The Sun has revealed that liquids possess a much greater potential for lattice order than previously believed. In addition, lessons may be gained with regards to the synthesis of liquid metallic hydrogen and the use of condensed matter as the basis for initiating fusion on Earth.

  5. On the Path to SunShot - Emerging Opportunities and Challenges in U.S. Solar Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Donald [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, Kelsey [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurup, Parthiv [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-05-01

    Innovation-driven cost and performance improvements, along with strong projected solar demand in the United States and across the Americas, could increase the attractiveness of U.S.-based solar manufacturing (see Chung et al. 2016). Although improvements to standard PV modules have produced deep cost reductions over the past 5 years, the returns on such incremental improvements appear to be diminishing, and more dramatic innovations in module design and manufacturing are required to continue along the path of rapid progress. At the same time, major opportunities exist for innovation to unlock the potential of CSP technologies. This need for innovation could benefit U.S. PV and CSP manufacturers. The United States has been rated one of the world’s most competitive and innovative countries as well as one of the best locations for PV manufacturing. It is a global leader in PV and CSP R&D and patent production, and U.S. PV manufacturers are already pursuing highly differentiated innovations.

  6. Verification of operational solar flare forecast: Case of Regional Warning Center Japan

    Science.gov (United States)

    Kubo, Yûki; Den, Mitsue; Ishii, Mamoru

    2017-08-01

    In this article, we discuss a verification study of an operational solar flare forecast in the Regional Warning Center (RWC) Japan. The RWC Japan has been issuing four-categorical deterministic solar flare forecasts for a long time. In this forecast verification study, we used solar flare forecast data accumulated over 16 years (from 2000 to 2015). We compiled the forecast data together with solar flare data obtained with the Geostationary Operational Environmental Satellites (GOES). Using the compiled data sets, we estimated some conventional scalar verification measures with 95% confidence intervals. We also estimated a multi-categorical scalar verification measure. These scalar verification measures were compared with those obtained by the persistence method and recurrence method. As solar activity varied during the 16 years, we also applied verification analyses to four subsets of forecast-observation pair data with different solar activity levels. We cannot conclude definitely that there are significant performance differences between the forecasts of RWC Japan and the persistence method, although a slightly significant difference is found for some event definitions. We propose to use a scalar verification measure to assess the judgment skill of the operational solar flare forecast. Finally, we propose a verification strategy for deterministic operational solar flare forecasting. For dichotomous forecast, a set of proposed verification measures is a frequency bias for bias, proportion correct and critical success index for accuracy, probability of detection for discrimination, false alarm ratio for reliability, Peirce skill score for forecast skill, and symmetric extremal dependence index for association. For multi-categorical forecast, we propose a set of verification measures as marginal distributions of forecast and observation for bias, proportion correct for accuracy, correlation coefficient and joint probability distribution for association, the

  7. Prototype of sun projector device

    Science.gov (United States)

    Ihsan; Dermawan, B.

    2016-11-01

    One way to introduce astronomy to public, including students, can be handled by solar observation. The widely held device for this purpose is coelostat and heliostat. Besides using filter attached to a device such as telescope, it is safest to use indirect way for observing the Sun. The main principle of the indirect way is deflecting the sun light and projecting image of the sun on a screen. We design and build a simple and low-cost astronomical device, serving as a supplement to increase public service, especially for solar observation. Without using any digital and intricate supporting equipment, people can watch and relish image of the Sun in comfortable condition, i.e. in a sheltered or shady place. Here we describe a design and features of our prototype of the device, which still, of course, has some limitations. In the future, this prototype can be improved for more efficient and useful applications.

  8. Center-to-Limb Variation of Solar 3-D Hydrodynamical Simulations

    CERN Document Server

    Koesterke, L; Lambert, D L

    2008-01-01

    We examine closely the solar Center-to-Limb variation of continua and lines and compare observations with predictions from both a 3-D hydrodynamic simulation of the solar surface (provided by M. Asplund and collaborators) and 1-D model atmospheres. Intensities from the 3-D time series are derived by means of the new synthesis code ASSET, which overcomes limitations of previously available codes by including a consistent treatment of scattering and allowing for arbitrarily complex line and continuum opacities. In the continuum, we find very similar discrepancies between synthesis and observation for both types of model atmospheres. This is in contrast to previous studies that used a ``horizontally'' and time averaged representation of the 3-D model and found a significantly larger disagreement with observations. The presence of temperature and velocity fields in the 3-D simulation provides a significant advantage when it comes to reproduce solar spectral line shapes. Nonetheless, a comparison of observed and s...

  9. Simulation of Sun Synchronous Orbit Satellite Solar Panel Control%太阳同步轨道卫星帆板对日定向控制与仿真

    Institute of Scientific and Technical Information of China (English)

    朱军年

    2011-01-01

    航天器所需能源南太阳能帆板提供.针对单翼、单自由度、匀速驱动的太阳同步轨道卫星帆板的对日定向控制问题,研究了轨道偏心率、地球非球形摄动、日月引力、大气阻力、太阳光乐等因素对卫星帆板对日定向精度的影响作用规律,为了提高对日帆板的定位控制精度,提出了在摄动影响下,采用线性拟合的方法,通过合理设置卫星帆板的驱动速度,延长卫星对日定向姿态的稳定时间.仿真结果表明,提出的方法简单易行,能够确保卫星帆板对日定向精度较长时间保持在允许范围内,在提高卫星帆板受晒效率的同时,减少了卫星帆板调整的次数.%Solar panel control problem for a sun synchronous orbit satellite, which has one degree freedom single solar panel droved by a constant velocity to point to the sun, is investigated in this paper. First of all, the rules are found out by simulation to express how the perturbations of orbit eccentricity, nonspherical acceleration, sun and lunar gravity, air drag and sun radiation pressure affect the solar panel attitude. Then, the changing rule of solar panel attitude angle is analyzed with integrated conditions considering all perturbations, and a linear fitting method is obtained. Then, the solar panel theoretic driving velocity is compensated with this method in order to keep solar panel in the optimal position for solarization. Simulation results indicate that the proposed method can keep the panel pointing to the sun for a relative long time, and reduce times to adjust the solar panel attitude.

  10. Solar 2 Green Energy, Arts & Education Center. Final Scientific/Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Paquette, Jamie C; Collins, Christopher J

    2011-07-18

    The Solar 2 Green Energy, Arts and Education Center is an 8,000 sq.ft. demonstration project that will be constructed to Platinum LEED certification and will be the first carbon-neutral, net-zero energy use public building in New York City, giving it local and national appeal. Employing green building features and holistic engineering practices throughout its international award-winning design, Solar 2 will be powered by a 90kW photovoltaic (PV) array in conjunction with a geothermal heating and cooling system and a high efficient design that seeks to reduce the overall energy load of the building. Solar 2 will replace our current 500 sq.ft. prototype facility - known as Solar 1 - as the educational and cultural centerpiece of a five-block public greenway on the East River in Stuyvesant Cove Park, located along two acres of public riverfront on a newly reclaimed, former brownfield in lower Manhattan. Designed as a public-use complex for year-round environmental education exhibits and onsite activities for all ages and backgrounds, Solar 2 will demonstrate energy-efficiency technologies and sustainable environmental practices available now to all urban residents, eco-tourists, teachers, and students alike. Showcasing one of Solar 2's most striking design elements is the PV roof array with a cafe and river vistas for miles of New York City's skylines. Capping the building as a solar-powered landmark, and visible from the FDR Drive, the PV array is also designed to provide visitors below a view of the solar roof when standing outside, as well as directly underneath it. Recognized by an international jury of architects, civil engineers and urban designers by the Swiss-based Holcim Foundation, the Solar 2 design was awarded the prestigious Holcim North American 2008 Gold Award for Sustainable Construction for innovative, future-oriented and tangible sustainable construction projects, selected from more than 1900 entries. Funding from the Department of Energy

  11. Efficiently Harvesting Sun Light for Silicon Solar Cells through Advanced Optical Couplers and A Radial p-n Junction Structure

    Directory of Open Access Journals (Sweden)

    Hsin-Cheng Lee

    2010-04-01

    Full Text Available Silicon-based solar cells (SCs promise to be an alternative energy source mainly due to: (1 a high efficiency-to-cost ratio, (2 the absence of environmental-degradation issues, and (3 great reliability. Transition from wafer-based to thin-film SC significantly reduces the cost of SCs, including the cost from the material itself and the fabrication process. However, as the thickness of the absorption (or the active layer decreases, the energy-conversion efficiency drops dramatically. As a consequence, we discuss here three techniques to increase the efficiency of silicon-based SCs: (1 photonic crystal (PC optical couplers and (2 plasmonic optical couplers to increase efficiency of light absorption in the SCs, and (3 a radial p-n junction structure, decomposing light absorption and diffusion path into two orthogonal directions. The detailed mechanisms and recent research progress regarding these techniques are discussed in this review article.

  12. Convectively driven vortex flows in the Sun

    CERN Document Server

    Bonet, J A; Almeida, J Sanchez; Cabello, I; Domingo, V

    2008-01-01

    We have discovered small whirlpools in the Sun, with a size similar to the terrestrial hurricanes (<~0.5 Mm). The theory of solar convection predicts them, but they had remained elusive so far. The vortex flows are created at the downdrafts where the plasma returns to the solar interior after cooling down, and we detect them because some magnetic bright points (BPs) follow a logarithmic spiral in their way to be engulfed by a downdraft. Our disk center observations show 0.009 vortexes per Mm^2, with a lifetime of the order of 5 min, and with no preferred sense of rotation. They are not evenly spread out over the surface, but they seem to trace the supergranulation and the mesogranulation. These observed properties are strongly biased by our type of measurement, unable to detect vortexes except when they are engulfing magnetic BPs.

  13. Energy Efficient Industrialized Housing Research Program, Center for Housing Innovation, University of Oregon and the Florida Solar Energy Center

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.Z.

    1990-01-01

    This research program addresses the need to increase the energy efficiency of industrialized housing. Two research centers have responsibility for the program: the Center for Housing Innovation at the University of Oregon and the Florida Solar Energy Center, a research institute of the University of Central Florida. The two organizations provide complementary architectural, systems engineering, and industrial engineering capabilities. In 1989 we worked on these tasks: (1) the formation of a steering committee, (2) the development of a multiyear research plan, (3) analysis of the US industrialized housing industry, (4) assessment of foreign technology, (5) assessment of industrial applications, (6) analysis of computerized design and evaluation tools, and (7) assessment of energy performance of baseline and advanced industrialized housing concepts. The current research program, under the guidance of a steering committee composed of industry and government representatives, focuses on three interdependent concerns -- (1) energy, (2) industrial process, and (3) housing design. Building homes in a factory offers the opportunity to increase energy efficiency through the use of new materials and processes, and to increase the value of these homes by improving the quality of their construction. Housing design strives to ensure that these technically advanced homes are marketable and will meet the needs of the people who will live in them.

  14. Solar space heating for the visitors' center, Stephens College, Columbia, Missouri. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Henley, Marion

    1980-06-01

    This document is the final report of the solar energy system located at the Visitors' Center on the Stephens College Campus, Columbia, Missouri. The system is installed in a four-story, 15,000 square foot building designed to include the college's Admission Office, nine guest rooms for overnight lodging for official guests of the college, a two-story art gallery, and a Faculty Lounge. The solar energy system is an integral design of the building and utilizes 176 Honeywell/Lennox hydronic flat-plate collectors which use a 50% water-ethylene glycol solution and water-to-water heat exchanger. Solar heated water is stored in a 5000 gallon water storage tank located in the basement equipment room. A natural gas fired hot water boiler supplies hot water when the solar energy heat supply fails to meet the demand. The designed solar contribution is 71% of the heating load. The demonstration period for this project ends June 30, 1984.

  15. 槽式太阳能跟踪控制系统的研制及应用%Development and application of sun-tracking control system for parabolic trough solar collector

    Institute of Scientific and Technical Information of China (English)

    王金平; 王军; 冯炜; 王登文; 张耀明

    2015-01-01

    Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Heat transfer fluid is heated by sun rays through the solar concentrator, then used as a heat source for a conventional power plant. A wide range of concentrating technologies has existed; the most developed are parabolic trough collector (PTC), linear fresnel reflector system (LF), power tower, and dish/engine system (DE). Parabolic trough collector is considered as one of the most mature applications of solar energy in these four technologies, which makes it worth developing. Sun-tracking system plays an important role in the development of solar energy applications, especially for the high solar concentration systems that directly convert the solar energy into thermal or electrical energy. High accuracy of sun-tracking is required to ensure that the solar collector is capable of harnessing the maximum solar energy throughout the day. Compared to fixed systems, power output of single-axis and dual-axis tracking systems can increase by 25% and 41% respectively under the same condition. It is clear that an accurate sun-tracking control system can make solar collectors receive more solar radiation energy to improve the solar energy utilization. A good sun-tracking system must be reliable and able to track the sun at the right angle even in the periods of cloud cover. Although the tracking system is more complex and costs higher than the fixed system, increasing the annual output power can reduce cost effectively. As for photoelectric tracking mode, a sun position sensor is used to provide feedback signals to judge where the sun is, but they don’t work on cloudy days because of the lower sensitivity. The stability of the solar tracking system is a key factor to obtain the maximum sunlight from parabolic trough collector. In order to improve tracking stability and accuracy of the parabolic trough collector sun-tracking control

  16. The Rapidly Rotating Sun

    Science.gov (United States)

    Hanasoge, Shravan M.; Duvall, Thomas L., Jr.; Sreenivasan, Katepalli R.

    2012-01-01

    Convection in the solar interior is thought to comprise structures at a continuum of scales, from large to small. This conclusion emerges from phenomenological studies and numerical simulations though neither covers the proper range of dynamical parameters of solar convection. In the present work, imaging techniques of time-distance helioseismology applied to observational data reveal no long-range order in the convective motion. We conservatively bound the associated velocity magnitudes, as a function of depth and the spherical-harmonic degree l to be 20-100 times weaker than prevailing estimates within the wavenumber band l ux of a solar luminosity outwards? The Sun is seemingly a much faster rotator than previously thought, with advection dominated by Coriolis forces at scales l < 60.

  17. Global Seismology of the Sun

    CERN Document Server

    Basu, Sarbani

    2016-01-01

    The seismic study of the Sun and other stars offers a unique window into the interior of these stars. Thanks to helioseismology, we know the structure of the Sun to admirable precision. In fact, our knowledge is good enough to use the Sun as a laboratory. We have also been able to study the dynamics of the Sun in great detail. Helioseismic data also allow us to probe the changes that take place in the Sun as solar activity waxes and wanes. The seismic study of stars other than the Sun is a fairly new endeavour, but we are making great strides in this field. In this review I discuss some of the techniques used in helioseismic analyses and the results obtained using those techniques. In this review I focus on results obtained with global helioseismology, i.e., the study of the Sun using its normal modes of oscillation. I also briefly touch upon asteroseismology, the seismic study of stars other than the Sun, and discuss how seismic data of others stars are interpreted.

  18. Watching the Sun to Improve Exoplanet Detection

    Science.gov (United States)

    Kohler, Susanna

    2015-12-01

    Looking for stars that wobble is one of the key ways by which we detect exoplanets: the gravitational pull of planets cause tiny variations in stars radial velocities. But our ability to detect Earth twins is currently limited by our ability to distinguish between radial-velocity variations caused by exoplanets, and those caused by noise from the star itself. A team of scientists has recently proposed that the key to solving this problem may be to examine our own star.Precision Amid NoiseThe radial-velocity technique works well for detecting large planets on close orbits, but detecting an Earth twin requires being able to detect star motion on the order of 10 cm/s! This precision is hard to reach, because activity on the stellar surface i.e., sunspots, plages (bright spots), or granulation can also cause variations in the measured radial velocity for the star, obscuring the signature of a planet.Because the stars were examining arent resolved, we cant track the activity on their surfaces so how can we better understand the imprint that stellar activity has on radial-velocity measurements? A team of scientists has come up with a clever approach: examine the Sun as though it were a distant star.Wealth of InformationThe team, led by Xavier Dumusque (Branco-Weiss Fellow at the Harvard-Smithsonian Center for Astrophysics) and David F. Phillips (Harvard-Smithsonian Center for Astrophysics), has begun a project to observe the Sun with a ground-based solar telescope. The telescope observes the full disk of the Sun and feeds the data into the HARPS-N spectrograph in Spain, a spectrograph normally used for radial-velocity measurements of other stars in the hunt for exoplanets.But the team has access to other data about the Sun, too: information from satellites like the Solar Dynamics Observatory and SORCE about the solar activity and total irradiance during the time when the spectra were taken. Dumusque and collaborators have combined all of this information, during a week

  19. Center-to-Limb Variation of Solar Granulation from Partial Eclipse Observations

    Science.gov (United States)

    Sánchez Cuberes, M.; Bonet, J. A.; Vázquez, M.; Wittmann, A. D.

    2000-08-01

    We have measured the center-to-limb variation (CLV) of parameters describing geometric and photometric statistical properties of the solar granulation at 6708 Å. This work is based on an excellent series of white-light images obtained with the Swedish Vacuum Solar Telescope at Roque de los Muchachos Observatory, La Palma, during the partial solar eclipse of 1994 May 10. The lunar limb profile, which is visible in each frame, was used as a calibration tool for estimating the point-spread function of the combined optical system formed by the atmosphere and the telescope. Before restoration, noise was removed from the images by a novel application of the so-called optimum filter for two-dimensional objects. The latter was optimized in terms of rms error and was constructed from very precise smoothed models of the specific power spectrum of the granulation at each position on the solar disk. The determination of the positions on the solar disk was achieved with high accuracy by matching the position of the Moon's limb in our images to a numerical simulation of the eclipse geometry. The CLV curve of the ΔIrms granular contrast shows one of the steepest gradients among those reported in the literature and quite a high value (9.6%) at the disk center considering that our working wavelength is in the far-red range of the solar spectrum. The elliptical shape of the restored power spectra with ellipticities equal to those expected just from foreshortening proves that radiative transfer effects do not alter the isotropy of the horizontal intensity pattern of the solar granulation, at least up to μ=0.4. The mean wavenumber, k, derived from the two-dimensional power spectra azimuthally integrated along the ellipses amounts to a value of 6.15 Mm-1 at the center of the solar disk and then shows a decrease toward the limb. Apart from the power spectra analysis, a direct statistical study of the granulation size and brightness, based on the image segmentation for defining

  20. Perspectives on the Interior of the Sun

    Indian Academy of Sciences (India)

    S. Μ. Chitre

    2000-09-01

    The interior of the Sun is not directly accessible to observations. Nonetheless, it is possible to infer the physical conditions inside the Sun with the help of structure equations governing its equilibrium and with the powerful observational tools provided by the neutrino fluxes and oscillation frequencies. The helioseismic data show that the internal constitution of the Sun can be adequately represented by a standard solar model. It turns out that a cooler solar core is not a viable solution for the measured deficit of neutrino fluxes, and the resolution of the solar neutrino puzzle should be sought in the realm of particle physics.

  1. Telescoping Shield for Point-Focusing Solar Concentrators

    Science.gov (United States)

    Argoud, M.; Walker, W.; Butler, L. V.

    1985-01-01

    Telescoping shield normally stowed around solar receiver protects heat engine and supporting structure from overheating when concentrator aimed few degrees away from line to Sun. When extended, shield intercepts off center concentrated solar radiation. Heat spread out over thermally conductive shield and reradiated diffusely not to cause structural damage.

  2. Isotopes Tell Sun's Origin and Operation

    Science.gov (United States)

    Manuel, O.; Kamat, Sumeet A.; Mozina, Michael

    2006-03-01

    Modern versions of Aston's mass spectrometer enable measurements of two quantities - isotope abundances and masses - that tell the Sun's origin and operation. Isotope analyses of meteorites, the Earth, Moon, Mars, Jupiter, the solar wind, and solar flares over the past 45 years indicate that fresh, poorly-mixed, supernova debris formed the solar system. The iron-rich Sun formed on the collapsed supernova core and now itself acts as a magnetic plasma diffuser, as did the precursor star, separating ions by mass. This process covers the solar surface with lightweight elements and with the lighter isotopes of each element. Running difference imaging provides supporting evidence of a rigid, iron-rich structure below the Sun's fluid outer layer of lightweight elements. Mass measurements of all 2,850 known nuclides expose repulsive interactions between neutrons that trigger neutron-emission at the solar core, followed by neutron-decay and a series of reactions that collectively generate solar luminosity, solar neutrinos, the carrier gas for solar mass separation, and an outpouring of solar-wind hydrogen from the solar surface. Neutron-emission and neutron-decay generate ~ 65% of solar luminosity; H-fusion ~ 35%, and ~ 1% of the neutron-decay product survives to depart as solar-wind hydrogen. The energy source for the Sun and other ordinary stars seems to be neutron-emission and neutron-decay, with partial fusion of the decay product, rather than simple fusion of hydrogen into helium or heavier elements.

  3. Teaching and sharing about the Sun in the United States and with Spanish language resources

    Science.gov (United States)

    Peticolas, L. M.; Craig, N.; Hawkins, I.; Walker, C.

    2007-05-01

    The United States has many different scientific agencies that fund research on solar science, including the National Aeronautics and Space Agency (NASA) and the National Science Foundation (NSF). Because there is a large population of Spanish-speaking people in the US, some of the resources developed by the education components of research projects take into account broader cultural perspectives on science and are developed in Spanish. We will describe the education and outreach programs of three solar programs funded by NASA and NSF, the Solar TErrestrial RElations Observatory (STEREO) program, the "We Are One Under the Sun" Program, and the National Optical Astronomy Observatory (NOAO) education program. The STEREO program aims to teach about the Sun through different venues including teacher workshops and courses, teacher materials, turning solar data from STEREO into sound, working with museums, and creating solar posters, CDs, DVDs, and lenticulars. The "We are One Under the Sun" program focuses on Native Americans and Hispanics of Native heritage. It works by merging culture, ancient observatories, and the latest NASA solar science to engage children, youth, and the general public in science and technology through solar traditions in their own indigenous culture. The NOAO Educational Outreach Program was established to make the science and scientists of NOAO more accessible to the K-12 and college-level communities. We will focus on the NOAO solar projects and Spanish-Language Astronomy Materials Educational Center program, which provides multiple types of Spanish- language materials for teachers. These programs have had different levels of outreach in Spanish-speaking countries, namely Mexico (STEREO and "We are One Under the Sun") and Chile (NOAO). We will describe these efforts and give links to the Spanish and English resources available to learn and teach about the Sun.

  4. Total eclipses of the sun.

    Science.gov (United States)

    Zirker, J B

    1980-12-19

    Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans.

  5. SOHO starts a revolution in the science of the Sun

    Science.gov (United States)

    1996-07-01

    In addition, SOHO has found clues to the forces that accelerate the solar wind of atomic particles blowing unceasingly through the Solar System. By relating the huge outbursts called coronal mass ejections to preceding magnetic changes in the Sun, SOHO scientists hope to predict such events which, in the Earth's vicinity, endanger power supplies and satellites. SOHO sees differences in the strength of the solar wind in various directions, by mapping a cavity in the cloud of interstellar hydrogen surrounding the Sun. As a bonus, SOHO secured remarkable images of Comet Hyakutake, by ultraviolet and visible light. The revolution in solar science will seem more complete when all the pieces and actions of the Sun, detected by twelve different instruments, are brought together in observations and concepts. Fundamental questions will then be open to re-examination, about the origin of the Sun's magnetism, the cause of its variations in the 11-year cycle of sunspot activity, and the consequences for the Solar System at large. SOHO is greater than the sum of its parts. "SOHO takes solar science by storm," says Roger Bonnet, the European Space Agency's Director of Science, "thanks to its combination of instruments. Unprecedented results from individual telescopes and spectrometers are impressive, of course, but what is breathtaking is SOHO's ability to explore the Sun all the way from its nuclear core to the Earth's vicinity and beyond. We can expect a completely new picture of how agitation inside the Sun, transmitted through the solar atmosphere, directly affects us on the Earth." SOHO is a project of international cooperation between the European Space Agency and NASA. The spacecraft was built in Europe and instrumented by scientists on both sides of the Atlantic. NASA launched SOHO and provides the ground stations and an operations centre at the Goddard Space Flight Center near Washington. SOHO has an uninterrupted view of the Sun from a halo orbit around Lagrangian

  6. Solar ultraviolet radiation in South Africa and sun-related knowledge, attitudes and behaviours among South African adults: pilot study results

    CSIR Research Space (South Africa)

    Wright, C

    2011-09-01

    Full Text Available While some sun exposure induces a sense of well-being and synthesis of vitamin D excess sun exposure has been associated with skin cancer, immune suppression and ocular cataracts. In South Africa, approximately 30% of all histologically...

  7. Totality eclipses of the Sun

    CERN Document Server

    Littmann, Mark; Willcox, Ken

    2008-01-01

    A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. - ;A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. Totality: Eclipses of the Sun is the best guide and reference book on solar eclipses ever written. It explains: how to observe them; how to photograph and videotape them; why they occur; their history and mythology; and future eclipses - when and where to see them. Totality also tells the remarkable story of how eclipses shocked scientists, revealed the workings of the Sun, and made Einstein famous. And the book shares the experiences and advice of many veteran eclipse observers. Totality: Eclipses of the Sun is profusely ill...

  8. Lissajous Orbit Control for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

    Science.gov (United States)

    Roberts, Craig; Case, Sarah; Reagoso, John

    2015-01-01

    DSCOVR Lissajous Orbit sized such that orbit track never extends beyond 15 degrees from Earth-Sun line (as seen from Earth). Requiring delta-V maneuvers, control orbit to obey a Solar Exclusion Zone (SEZ) cone of half-angle 4 degrees about the Earth-Sun line. Spacecraft should never be less than 4 degrees from solar center as seen from Earth. Following Lissajous Orbit Insertion (LOI), DSCOVR should be in an opening phase that just skirts the 4-degree SEZ. Maximizes time to the point where a closing Lissajous will require avoidance maneuvers to keep it out of the SEZ. Station keeping maneuvers should take no more than 15 minutes.

  9. Eruptions from the Sun

    Science.gov (United States)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  10. Electron Temperatures and Flow Speeds of the Low Solar Corona: MACS Results from the Total Solar Eclipse of 29 March 2006 in Libya

    Science.gov (United States)

    Reginald, Nelson L.; Davila, Joseph M.; SaintCyr, O.; Rabin, Douglas M.; Guhathakurta, Madhulika; Hassler, Donald M.; Gashut, Hadi

    2011-01-01

    An experiment was conducted in conjunction with the total solar eclipse on 29 March 2006 in Libya to measure both the electron temperature and its flow speed simultaneously at multiple locations in the low solar corona by measuring the visible K-coronal spectrum. Coronal model spectra incorporating the effects of electron temperature and its flow speed were matched with the measured K-coronal spectra to interpret the observations. Results show electron temperatures of (1.10 +/- 0.05) MK, (0.70 +/- 0.08) MK, and (0.98 +/- 0.12) MK, at 1.1 Solar Radius from Sun center in the solar north, east and west, respectively, and (0.93 +/- 0.12) MK, at 1.2 Solar Radius from Sun center in the solar west. The corresponding outflow speeds obtained from the spectral fit are (103 +/- 92) km/s, (0 + 10) km/s, (0+10) km/s, and (0+10) km/s. Since the observations were taken only at 1.1 Solar Radius and 1.2 Solar Radius from Sun center, these speeds, consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working. The electron temperature at 1.1 Solar Radius from Sun center is larger at the north (polar region) than the east and west (equatorial region).

  11. Electron Temperatures and Flow Speeds of the Low Solar Corona: MACS Results from the Total Solar Eclipse of 29 March 2006 in Libya

    Science.gov (United States)

    Reginald, Nelson L.; Davila, Joseph M.; SaintCyr, O.; Rabin, Douglas M.; Guhathakurta, Madhulika; Hassler, Donald M.; Gashut, Hadi

    2011-01-01

    An experiment was conducted in conjunction with the total solar eclipse on 29 March 2006 in Libya to measure both the electron temperature and its flow speed simultaneously at multiple locations in the low solar corona by measuring the visible K-coronal spectrum. Coronal model spectra incorporating the effects of electron temperature and its flow speed were matched with the measured K-coronal spectra to interpret the observations. Results show electron temperatures of (1.10 +/- 0.05) MK, (0.70 +/- 0.08) MK, and (0.98 +/- 0.12) MK, at 1.1 Solar Radius from Sun center in the solar north, east and west, respectively, and (0.93 +/- 0.12) MK, at 1.2 Solar Radius from Sun center in the solar west. The corresponding outflow speeds obtained from the spectral fit are (103 +/- 92) km/s, (0 + 10) km/s, (0+10) km/s, and (0+10) km/s. Since the observations were taken only at 1.1 Solar Radius and 1.2 Solar Radius from Sun center, these speeds, consistent with zero outflow, are in agreement with expectations and provide additional confirmation that the spectral fitting method is working. The electron temperature at 1.1 Solar Radius from Sun center is larger at the north (polar region) than the east and west (equatorial region).

  12. NEW SUNS IN THE COSMOS?

    Energy Technology Data Exchange (ETDEWEB)

    De Freitas, D. B.; Leao, I. C.; Lopes, C. E. Ferreira; Paz-Chinchon, F.; Canto Martins, B. L.; Alves, S.; De Medeiros, J. R. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Catelan, M. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago (Chile)

    2013-08-20

    The present work reports on the discovery of three stars that we have identified to be rotating Sun-like stars, based on rotational modulation signatures inferred from light curves from the CoRoT mission's Public Archives. In our analysis, we performed an initial selection based on the rotation period and position in the period-T{sub eff} diagram. This revealed that the stars CoRoT IDs 100746852, 102709980, and 105693572 provide potentially good matches to the Sun with a similar rotation period. To refine our analysis, we applied a novel procedure, taking into account the fluctuations of the features associated with photometric modulation at different time intervals and the fractality traces that are present in the light curves of the Sun and of these ''New Sun'' candidates alike. In this sense, we computed the so-called Hurst exponent for the referred stars, for a sample of 14 CoRoT stars with sub- and super-solar rotational periods, and for the Sun itself in its active and quiet phases. We found that the Hurst exponent can provide a strong discriminant of Sun-like behavior, going beyond what can be achieved with solely the rotation period itself. In particular, we find that CoRoT ID 105693572 is the star that most closely matches the solar rotation properties as far as the latter's imprints on light curve behavior are concerned. The stars CoRoT IDs 100746852 and 102709980 have significant smaller Hurst exponents than the Sun, notwithstanding their similarity in rotation periods.

  13. Quality site seasonal report, Tucson Job Corps Center, SFBP (Solar in Federal Buildings Program) 1751, November 1984 through July 1985

    Energy Technology Data Exchange (ETDEWEB)

    Logee, T.L.

    1987-10-15

    The active solar Domestic Hot Water (DHW) system at the Tucson Job Corps Center was designed and constructed as part of the Solar in Federal Buildings Program (SFBP). This retrofitted system is one of eight of the systems in the SFBP selected for quality monitoring. The purpose of this monitoring effort is to document the performance of quality state-of-the-art solar systems in large Federal buildings. The systems are unique prototypes. Design errors and system faults discovered during the monitoring period could not always be corrected. Therefore, the aggregated overall performance is often considerably below what might be expected had similar systems been constructed consecutively with each repetition incorporating corrections and improvements. The solar collector system is installed on a two story dormitory at the Job Corps Center. The solar system preheats hot water for about two hundred students. The solar system provided about 50% of the energy needed for water heating in the winter and nearly 100% of the water heating needs in the summer. There are about 70,000 gallons of water used per month. There are seventy-nine L.O.F. panels or 1659 square feet of collectors (1764 square feet before freeze damage occurred) mounted in two rows on the south facing roof. Collected solar energy is stored in the 2200-gallon storage tank. The control system is by Johnson Controls. City water is piped directly to the storage tank and is circulated in the collectors. Freeze protection is provided by recirculation of storage water. There is an auxiliary gas fired boiler and 750 gallon DHW storage tank to provide backup for the solar system. Highlights of the performance monitoring from the solar collection system at the Tucson Job Corps Center during the November 1984 through July 1985 monitoring period are presented in this report.

  14. Sun light European Project

    Science.gov (United States)

    Soubielle, Marie-Laure

    2015-04-01

    2015 has been declared the year of light. Sunlight plays a major role in the world. From the sunbeams that heat our planet and feed our plants to the optical analysis of the sun or the modern use of sun particles in technologies, sunlight is everywhere and it is vital. This project aims to understand better the light of the Sun in a variety of fields. The experiments are carried out by students aged 15 to 20 in order to share their discoveries with Italian students from primary and secondary schools. The experiments will also be presented to a group of Danish students visiting our school in January. All experiments are carried out in English and involve teams of teachers. This project is 3 folds: part 1: Biological project = what are the mechanisms of photosynthesis? part 2: Optical project= what are the components of sunlight and how to use it? part 3: Technical project= how to use the energy of sunlight for modern devices? Photosynthesis project Biology and English Context:Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can later fuel the organisms' activities. This chemical energy is stored in molecules which are synthesized from carbon dioxide and water. In most cases, oxygen is released as a waste product. Most plants perform photosynthesis. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth. Outcome: Our project consists in understanding the various steps of photosynthesis. Students will shoot a DVD of the experiments presenting the equipments required, the steps of the experiments and the results they have obtained for a better understanding of photosynthesis Digital pen project Electricity, Optics and English Context: Sunlight is a complex source of light based on white light that can be decomposed to explain light radiations or colours. This light is a precious source to create

  15. The Sun: Our Nearest Star

    Science.gov (United States)

    Adams, M. L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We have in our celestial backyard, a prime example of a variable star. The Sun, long thought to be "perfect" and unvarying, began to reveal its cycles in the early 1600s as Galileo Galilei and Christoph Scheiner used a telescope to study sunspots. For the past four hundred years, scientists have accumulated data, showing a magnetic cycle that repeats, on average, every eleven (or twenty-two) years. In addition, modern satellites have shown that the energy output at radio and x-ray wavelengths also varies with this cycle. This talk will showcase the Sun as a star and discuss how solar studies may be used to understand other stars.

  16. Sun exposure and sun protection habits in high school students from a city south of the country Práticas de exposição e proteção solar em estudantes do ensino médio de uma cidade do sul do país

    Directory of Open Access Journals (Sweden)

    Letícia Dupont

    2012-02-01

    Full Text Available BACKGROUND: Effective solar protection is an uncommon practice among young people, increasing the likelihood of sunburn, sunstroke and skin cancers. This fact is more significant in the south of Brazil, where the prevalence of white skinned population is larger, being more prone to sun damage. OBJECTIVES: To study the practices of sun exposure and sun protection in high school students from the city of Carlos Barbosa - RS. METHODS: Cross-sectional study involving 775 students, enrolled on the first half of 2010, who had signed the consent form. We used a non-identifiable, self-administered questionnaire, with questions about related topics. Statistical analysis was performed using Chi-square or Fisher exact and t-Student tests. The study was approved by the Research Ethics Committee under the number 2010-115H. RESULTS: Most students are exposed to the sun at the more critical periods, remaining exposed for more than an hour. Five hundred and seventy-six students (74,3% reported using sunscreen, but less than 10% did it during all months of the year. Female teenagers are most likely to use sunscreen (p FUNDAMENTOS: A proteção solar efetiva é uma prática incomum entre os jovens, aumentando a probabilidade de queimaduras solares, insolações e cânceres de pele. Esse fato é mais significativo na Região Sul do Brasil, onde a prevalência da população branca é maior, sendo mais propensa aos danos causados pelo sol. OBJETIVOS: Estudar as práticas de exposição e proteção solar em estudantes do ensino médio da cidade de Carlos Barbosa, RS. MÉTODOS: Estudo transversal, envolvendo 775 estudantes matriculados no primeiro semestre de 2010, que tiveram o termo de consentimento assinado. Utilizou-se um questionário não identificável, autoaplicável, com perguntas abordando tópicos relacionados ao tema. Na análise estatística, foram utilizados os testes qui-quadrado ou exato de Fisher e o teste t-Student. O estudo foi aprovado pelo Comit

  17. Long-term migration of the solar sector structure

    Science.gov (United States)

    Wolff, C. L.; Heath, D. F.

    1979-01-01

    The magnetic sector boundaries on the sun and in the solar wind are shown to have a high correlation with winter low pressure systems on earth. The vorticity-area index typically declines by about 10% during several days centered on the time when a sector boundary sweeps past the earth. Evidence that both the sector structure and solar activity levels can be understood as being under the influence of the same regular, internal solar mechanism is presented.

  18. Solar Refrigerators Store Life-Saving Vaccines

    Science.gov (United States)

    2014-01-01

    Former Johnson Space Center engineer David Bergeron used his experience on the Advanced Refrigeration Technology Team to found SunDanzer Refrigeration Inc., a company specializing in solar-powered refrigerators. The company has created a battery-free unit that provides safe storage for vaccines in rural and remote areas around the world.

  19. Sun-earth connection education through modern views of ancient

    Science.gov (United States)

    Thieman, J. R.

    The NASA Sun-Earth Connection Education Forum (SECEF) has the responsibility of using the latest science results from the study of solar physics, space physics, and aeronomy to inspire students in the classroom and to inform the public in general. SECEF works with NASA's Sun-Earth Connection spaceflight missions to accomplish this goal. Each year the missions and SECEF combine to promote their science through a major event designed to attract the attention of all. In late 2004 and 2005 the event will be the study of solar observatories created by ancient peoples and a comparison of their knowledge and culture to present understanding. Two solar observatory sites will be featured, Chaco Canyon in the U.S. and Chichen Itza in Mexico. There are many other places throughout the world that could also be featured as solar observatories and some of these may be described on the SECEF web site or used in future occurrences. Special emphasis is placed on events associated with the solstice and equinox dates. It is hoped that there will be happenings around the world on these days and SECEF will work with many museums, science centers, and other groups to help make this happen. Plans for the 2005 Ancient Observatories event and possible future events on the same subject will be described.

  20. How to Observe the Sun Safely

    CERN Document Server

    Macdonald, Lee

    2012-01-01

    How to Observe the Sun Safely, Second Edition gives all the basic information and advice the amateur astronomer needs to get started in observing our own ever-fascinating star. Unlike many other astronomical objects, you do not need a large telescope or expensive equipment to observe the Sun. And it is possible to take excellent pictures of the Sun with today's low-cost digital cameras! This book surveys what is visible on the Sun and then describes how to record solar features and measure solar activity levels. There is also an account of how to use H-alpha and Calcium-K filters to observe and record prominences and other features of the solar chromosphere, the Sun's inner atmosphere. Because we are just entering a period of high activity on the Sun, following a long, quiet period, this is a great time to get involved with solar observing. Still emphasizing safety first, this Second Edition reflects recent and exciting advances in solar observing equipment. Chapters 6 through 8 have been completely revised ...

  1. Design of a Glenn Research Center Solar Field Grid-Tied Photovoltaic Power System

    Science.gov (United States)

    Eichenberg, Dennis J.

    2009-01-01

    The NASA Glenn Research Center (GRC) designed, developed, and installed, a 37.5 kW DC photovoltaic (PV) Solar Field in the GRC West Area in the 1970s for the purpose of testing PV panels for various space and terrestrial applications. The PV panels are arranged to provide a nominal 120 VDC. The GRC Solar Field has been extremely successful in meeting its mission. The PV panels and the supporting electrical systems are all near their end of life. GRC has designed a 72 kW DC grid-tied PV power system to replace the existing GRC West Area Solar Field. The 72 kW DC grid-tied PV power system will provide DC solar power for GRC PV testing applications, and provide AC facility power for all times that research power is not required. A grid-tied system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility for use by all. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. The report concludes that the GRC West Area grid-tied PV power system design is viable for a reliable

  2. Observational manifestations of solar magneto-convection -- center-to-limb variation

    CERN Document Server

    Carlsson, M; Nordlund, A; Scharmer, G; Carlsson, Mats; Stein, Robert F.; Nordlund, Ake; Scharmer, Goran

    2004-01-01

    We present the first center-to-limb G-band images synthesized from high resolution simulations of solar magneto-convection. Towards the limb the simulations show "hilly" granulation with dark bands on the far side, bright granulation walls and striated faculae, similar to observations. At disk center G-band bright points are flanked by dark lanes. The increased brightness in magnetic elements is due to their lower density compared with the surrounding intergranular medium. One thus sees deeper layers where the temperature is higher. At a given geometric height, the magnetic elements are cooler than the surrounding medium. In the G-band, the contrast is further increased by the destruction of CH in the low density magnetic elements. The optical depth unity surface is very corrugated. Bright granules have their continuum optical depth unity 80 km above the mean surface, the magnetic elements 200-300 km below. The horizontal temperature gradient is especially large next to flux concentrations. When viewed at an ...

  3. Johnson Space Center's Solar and Wind-Based Renewable Energy System

    Science.gov (United States)

    Vasquez, A.; Ewert, M.; Rowlands, J.; Post, K.

    2009-01-01

    The NASA Johnson Space Center (JSC) in Houston, Texas has a Sustainability Partnership team that seeks ways for earth-based sustainability practices to also benefit space exploration research. A renewable energy gathering system was installed in 2007 at the JSC Child Care Center (CCC) which also offers a potential test bed for space exploration power generation and remote monitoring and control concepts. The system comprises: 1) several different types of photovoltaic panels (29 kW), 2) two wind-turbines (3.6 kW total), and 3) one roof-mounted solar thermal water heater and tank. A tie to the JSC local electrical grid was provided to accommodate excess power. The total first year electrical energy production was 53 megawatt-hours. A web-based real-time metering system collects and reports system performance and weather data. Improvements in areas of the CCC that were detected during subsequent energy analyses and some concepts for future efforts are also presented.

  4. Spicules and their on-disk counterparts, the main driver for solar chromospheric heating?

    CERN Document Server

    Puschmann, Klaus Gerhard

    2016-01-01

    The question how the outer solar atmosphere is heated from solar photospheric temperatures of about 5800K up to solar chromospheric and coronal temperatures of about 20 000K and millions of degrees respectively, remained without any satisfying answer for centuries. On 4 May 2005, I recorded several time series of Halpha line scans with the GREGOR Fabry-Perot Interferometer, still deployed at the German Vacuum Tower Telescope (VTT), for different solar limb and on-disc positions as well for quiet sun at solar disk center. The spatially and temporally highly resolved time series of Halpha line parameters reveal the entire and detailed complexity as well as the overwhelming dynamics of spicules covering the entire solar disk, thus apparently confirming spicules as the potential driver for chromospheric heating of both the Sun and sun-like stars.

  5. Lightcurves of Jovian Trojan Asteroids from the Center for Solar System Studies: L4 Greek Camp and Spies

    Science.gov (United States)

    Stephens, Robert D.; Coley, Daniel R.; Warner, Brian D.; French, Linda, M.

    2016-10-01

    Jovian Trojan asteroids larger than ~ 30 km were studied from the Center for Solar System Studies (CS3, MPC U81). Lightcurves for 30 Trojan asteroids in the L4 (Greek) cloud were between May and June 2016. These were mostly from the L4 "Greek" cloud, but several were L5 "Trojan" cloud lightcurves not previously published.

  6. Design of automatic real-time system with solar panels for sun tracking%太阳能电池自动实时逐日系统设计

    Institute of Scientific and Technical Information of China (English)

    蔡荣山; 杨勇; 张虹; 姚桔

    2016-01-01

    采用非易失实时时钟芯片DS12C887配合SPA算法,精确获取所在地实时太阳方位;单片机根据光功率评估电池方位驱动后所获电能及驱动耗电,优化驱动的时间间隔;不驱动时,系统掉电.该方案具有断电重启方便,实时跟踪,太阳能电池效能高的优势,具有一定的应用价值.%This scheme uses a nonvolatile real-time clock chip DS12C887 to precisely obtain realtime position of the sun by adopting SPA algorithm.SCM assesses the obtained electrical energy and driving energy consumption according to the optical power after the direction driving of the solar cell,and then optimizes the intervals of the driving.The system is in a brown-out condition when it is not driving.This scheme has the following advantages:convenient re-initialization after outage,real-time sun-tracking function,efficient solar cells and some application values.

  7. Covert Operation ``Sun God'' - History of German Solar Research in the Third Reich and Under Allied Occupation (German Title: Kommandosache ``Sonnengott'' - Geschichte der deutschen Sonnenforschung im Dritten Reich und unter alliierter Besatzung)

    Science.gov (United States)

    Seiler, Michael P.

    Between 1939 and 1945 the Luftwaffe of the Third Reich invested large sums in solar research and the establishment of a chain of solar observatories under the code word “Sun God”. Observations of the different phenomena of solar activity were intended to allow a dependable daily prediction of the best frequency bands for long-range military radio. For the development of these research activities the Luftwaffe used a young astrophysicist, who - being the son of a well-known leftist publisher of the Weimar Republic - did appear not well suited to perform “war decisive research” for the Nazi regime: Karl-Otto Kiepenheuer (1910-1975). Circumventing the usual academic tenure, Hitler's war turned the barely thirty-year-old and up to then rather unsuccessful Kiepenheuer into an influential director of a research institution, which he was to remain for the next three decades as well. This book recounts the history of German solar research in the period 1939-1949, her entanglement with the crimes of the Nazi regime as well as her use by the Western Allies until the founding of the German Federal Republic.

  8. Liquid Metallic Hydrogen: A Building Block for the Liquid Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available Liquid metallic hydrogen provides a compelling material for constructing a condensed matter model of the Sun and the photosphere. Like diamond, metallic hydrogen might have the potential to be a metastable substance requiring high pressures for forma- tion. Once created, it would remain stable even at lower pressures. The metallic form of hydrogen was initially conceived in 1935 by Eugene Wigner and Hillard B. Huntington who indirectly anticipated its elevated critical temperature for liquefaction (Wigner E. and Huntington H.B. On the possibility of a metallic modification of hydro- gen. J. Chem. Phys. , 1935, v.3, 764–770. At that time, solid metallic hydrogen was hypothesized to exist as a body centered cubic, although a more energetically accessible layered graphite-like lattice was also envisioned. Relative to solar emission, this struc- tural resemblance between graphite and layered metallic hydrogen should not be easily dismissed. In the laboratory, metallic hydrogen remains an elusive material. However, given the extensive observational evidence for a condensed Sun composed primarily of hydrogen, it is appropriate to consider metallic hydrogen as a solar building block. It is anticipated that solar liquid metallic hydrogen should possess at least some layered order. Since layered liquid metallic hydrogen would be essentially incompressible, its invocation as a solar constituent brings into question much of current stellar physics. The central proof of a liquid state remains the thermal spectrum of the Sun itself. Its proper understanding brings together all the great forces which shaped modern physics. Although other proofs exist for a liquid photosphere, our focus remains solidly on the generation of this light.

  9. The Sun A User's Manual

    CERN Document Server

    Vita-Finzi, Claudio

    2008-01-01

    The Sun is an account of the many ways in which our nearest star affects our planet, how its influence has changed over the last few centuries and millennia, and the extent to which we can predict its future impact. The Sun's rays foster the formation of Vitamin D by our bodies, but it can also promote skin cancer, cataracts, and mutations in our DNA. Besides providing the warmth and light essential to most animal and plant life, solar energy contributes substantially to global warming. Although the charged particles of the solar wind shield us from harmful cosmic rays, solar storms may damage artificial satellites and cripple communication systems and computer networks. The Sun is the ideal renewable energy source, but its exploitation is still bedevilled by the problems of storage and distribution. Our nearest star, in short, is a complex machine which needs to be treated with caution, and this book will equip every reader with the knowledge that is required to understand the benefits and dangers it can bri...

  10. SORCE: Solar Radiation and Climate Experiment

    Science.gov (United States)

    Cahalan, Robert; Rottman, Gary; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Contents include the following: Understanding the Sun's influence on the Earth; How the Sun affect Earth's climate; By how much does the Sun's radiation very; Understanding Solar irradiance; History of Solar irradiance observations; The SORCE mission; How do the SORCE instruments measure solar radiation; Total irradiance monitor (TIM); Spectral irradiance monitor (SIM); Solar stellar irradiance comparison experiment (SOLSTICE); XUV photometer system (XPS).

  11. Sun-protective Behaviors of Student Spectators at Inter-school Swimming Carnivals in a Tropical Region of High Ambient Solar Ultraviolet Radiation.

    Directory of Open Access Journals (Sweden)

    Denise Turner

    2016-08-01

    Full Text Available Skin cancer is the most common cancer in humans and Australia (particularly in Queensland has the highest incidence globally. Sunlight is a known skin carcinogen and reflects off water, exacerbating the risk of sunburn. In 1988, the SunSmart Program was developed to promote sun-protection to Australian children. Within a decade, it evolved to include a voluntary national accreditation program for schools, known as the SunSmart Schools (SSS Program. Additionally, in 2008, it became compulsory for primary schoolchildren attending Queensland government-funded schools to wear a shirt during all water-based activities, except when competing. We observed the proportion of student spectators from 41 Townsville (latitude 19.3°S primary schools (65.9% SSS wearing hats at inter-school swimming carnivals in 2009-2011 and 2015 and the proportion wearing a shirt. Overall, a median of 30.7% student spectators from each school wore a hat (max 46.2% [2009]; min 18% [2015] and 77.3% wore a shirt (max 95.8% [2009]; min 74.5% [2015], suggesting that hats are under-utilized. Students from non-government (private schools were twice as likely as students from government schools to wear a hat (41% vs 18.2% p=0.003. Neither the hat nor the shirt-wearing behaviors of student spectators were significantly influenced by their school’s size (number of students, educational advantage, sun-protection policy score or SunSmart status, indicating that other socio-economic factors, not assessed here, may have influenced the results. Our findings suggest that the mandatory swim-shirt policy introduced in 2008 was very effective, especially initially. However, monitoring and feedback of results to schools may be needed to maintain high levels of compliance in the longer-term. Schoolchildren attending swimming carnivals should not rely on sunscreen or shade alone to protect against direct and reflected-sunlight, and need prompting to put a hat and shirt back on immediately after

  12. The Sun Radio Imaging Space Experiment (SunRISE) Mission

    Science.gov (United States)

    Lazio, Joseph; Kasper, Justin; Maksimovic, Milan; Alibay, Farah; Amiri, Nikta; Bastian, Tim; Cohen, Christina; Landi, Enrico; Manchester, Ward; Reinard, Alysha; Schwadron, Nathan; Cecconi, Baptiste; Hallinan, Gregg; Hegedus, Alex; Krupar, Vratislav; Zaslavsky, Arnaud

    2017-04-01

    Radio emission from coronal mass ejections (CMEs) is a direct tracer of particle acceleration in the inner heliosphere and potential magnetic connections from the lower solar corona to the larger heliosphere. Energized electrons excite Langmuir waves, which then convert into intense radio emission at the local plasma frequency, with the most intense acceleration thought to occur within 20 RS. The radio emission from CMEs is quite strong such that only a relatively small number of antennas is required to detect and map it, but many aspects of this particle acceleration and transport remain poorly constrained. Ground-based arrays would be quite capable of tracking the radio emission associated with CMEs, but absorption by the Earth's ionosphere limits the frequency coverage of ground-based arrays (ν ≳ 15 MHz), which in turn limits the range of solar distances over which they can track the radio emission (≲ 3RS). The state-of-the-art for tracking such emission from space is defined by single antennas (Wind/WAVES, Stereo/SWAVES), in which the tracking is accomplished by assuming a frequency-to-density mapping; there has been some success in triangulating the emission between the spacecraft, but considerable uncertainties remain. We describe the Sun Radio Imaging Space Experiment (SunRISE) mission concept: A constellation of small spacecraft in a geostationary graveyard orbit designed to localize and track radio emissions in the inner heliosphere. Each spacecraft would carry a receiving system for observations below 25 MHz, and SunRISE would produce the first images of CMEs more than a few solar radii from the Sun. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  13. 15 CFR 950.5 - National Geophysical and Solar-Terrestrial Data Center (NGSDC).

    Science.gov (United States)

    2010-01-01

    ... COMMERCE GENERAL REGULATIONS OF THE ENVIRONMENTAL DATA SERVICE ENVIRONMENTAL DATA AND INFORMATION § 950.5...-A (Solid-Earth Geophysics, Solar Terrestrial Physics, and Glaciology). (a) Geophysical and solar... geological data, including data on heat flow, cores, samples, and sediments. (2) Solar-Terrestrial physics...

  14. New insight into Earth's weather through studies of Sun's magnetic fields

    Science.gov (United States)

    1990-01-01

    Solar Vector Magnetograph is used to predict solar flares, and other activities associated with sun spots. This research provides new understanding about weather on the Earth, and solar-related conditions in orbit.

  15. Polar migration of prominences and the inversion of the polar magnetic field of the sun in the 11th and 12th solar cycles (1869 - 1885).

    Science.gov (United States)

    Makarov, V. I.

    The trajectories of the polar migration of prominences are calculated on the basis of spectroscopic observations of prominences during 1869 - 1885. The epoch of the polarity inversion of the polar magnetic field is determined. Three "waves" of migration of polar prominences were observed in the southern hemisphere in the 12th solar cycle whose velocities were 3.9, 7.0 and 8.3 m sec-1. In the northern hemisphere only one "wave" of migration was observed whose velocity was 4.0 m sec-1. The 12th solar cycle is similar to the 14th solar cycle from the point of view of polar migration of prominences.

  16. The Sun in Time: Activity and Environment

    CERN Document Server

    Güdel, M

    2007-01-01

    (abridged) The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels, its faster rotation generated enhanced magnetic activity; magnetic heating processes in the chromosphere, the transition region, and the corona induced ultraviolet, extreme-ultraviolet, and X-ray emission about 10, 100, and 1000 times, respectively, the present-day levels, as inferred from young solar-analog stars. Also, the production rate of accelerated, high-energy particles was orders of magnitude higher than in present-day solar flares, and a much stronger wind escaped from the Sun, permeating the entire solar system. The consequences of the enhanced radiation and particle fluxes from the young Sun were potentially severe for the evolution of solar-system planets and moons. Interactions of high-energy radiation and the solar wind with upper planetary atmospheres may have...

  17. Power producing sun shades; Elproducerende solafskaermninger

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, K.; Soerensen, Henrik; Katic, I.; Schmidt-Petersen, H.; AAroe, D.

    2012-01-15

    Integrating photovoltaics into sun shades takes advantage of the best opportunities to capture and utilize solar energy when the shades are most needed to shield users from solar radiation. The report describes results of a development project for solar shading in the form of broad, horizontal and rotating lamellae with solar cells and an integrated control function that simultaneously is optimized based on energy consumption and thermal and visual indoor climate. The project idea was to meet the needs for effective sun protection in the present office, commercial and public buildings, where glass facades are dominant. The conclusion of the development project is that it rarely would be optimal to integrate solar cells into movable shades. This will normally only be relevant in cases where it is justified by architectural considerations. (LN)

  18. The EUV emission from sun-grazing comets

    OpenAIRE

    Bryans, Paul; Pesnell, W Dean

    2012-01-01

    The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) has observed two sun-grazing comets as they passed through the solar atmosphere. Both passages resulted in a measurable enhancement of Extreme Ultraviolet (EUV) radiance in several of the AIA bandpasses. We explain this EUV emission by considering the evolution of the cometary atmosphere as it interacts with the ambient solar atmosphere. Molecules in the comet rapidly sublimate as it approaches the Sun. They are th...

  19. Ra: The Sun for Science and Humanity

    Science.gov (United States)

    1996-01-01

    To guide the development of the Ra Strategic Framework, we defined scientific and applications objectives. For our primary areas of scientific interest, we choose the corona, the solar wind, the Sun's effect on the Earth, and solar theory and model development. For secondary areas of scientific interest, we selected sunspots, the solar constant, the Sun's gravitational field, helioseismology and the galactic cosmic rays. We stress the importance of stereoscopic imaging, observations at high spatial, spectral, and temporal resolutions, as well as of long duration measurements. Further exploration of the Sun's polar regions is also important, as shown already by the Ulysses mission. From an applications perspective, we adopted three broad objectives that would derive complementary inputs for the Strategic Framework. These were to identify and investigate: possible application spin-offs from science missions, possible solar-terrestrial missions dedicated to a particular application, and possible future applications that require technology development. The Sun can be viewed as both a source of resources and of threats. Our principal applications focus was that of threat mitigation, by examining ways to improve solar threat monitoring and early warning systems. We compared these objectives to the mission objectives of past, current, and planned international solar missions. Past missions (1962-1980) seem to have been focused on improvement of scientific knowledge, using multiple instrument spacecraft. A ten year gap followed this period, during which the results from previous missions were analyzed and solar study programmes were prepared in international organizations. Current missions (1990-1996) focus on particular topics such as the corona, solar flares, and coronal mass ejections. In planned missions, Sun/Earth interactions and environmental effects of solar activity are becoming more important. The corona is the centre of interest of almost all planned missions

  20. Early solar physics

    CERN Document Server

    Meadows, A J

    1970-01-01

    Early Solar Physics reviews developments in solar physics, particularly the advent of solar spectroscopy and the discovery of relationships between the various layers of the solar atmosphere and between the different forms of solar activity. Topics covered include solar observations during 1843; chemical analysis of the solar atmosphere; the spectrum of a solar prominence; and the solar eclipse of December 12, 1871. Spectroscopic observations of the sun are also presented. This book is comprised of 30 chapters and begins with an overview of ideas about the sun in the mid-nineteenth century, fo

  1. Indoor test for thermal performance evaluation of Lenox-Honeywell solar collector. [conducted using Marshall Space Flight Center Solar Simulator

    Science.gov (United States)

    Shih, K.

    1977-01-01

    The test procedures used and the test results obtained from an evaluation test program conducted on a double-covered liquid solar collector under simulated conditions are presented. The test article was a flat plate solar collector using liquid as the heat transfer medium. The absorber plate was steel with the copper tubes bonded on the upper surface. The plate was coated with black chrome with an absorptivity factor of .95 and emissivity factor of .12. A time constant test and incident angle modifier test were conducted to determine the transient effect and the incident angle effect on the collector.

  2. The sun since the Bronze Age

    Science.gov (United States)

    Eddy, J. A.

    1976-01-01

    An investigation is conducted concerning the behavior of the sun during the last 7000 years. The C-14 content in carbonaceous fossil material can be used as an indicator regarding the level of solar activity at the time when the carbon was assimilated in the process of photosynthesis. Living trees, such as the bristlecone pine, provide a solar activity record to about 3000 B.C. The record can be extended with the aid of well-preserved dead wood to beyond 5000 B.C. The results of an analysis of solar activity levels as a function of time on the basis of C-14 contents are presented in a graph. Attention is given to the Maunder Minimum, a history of the sun in the last 5000 years, an interpretation of the major C-14 excursions, and the sun and climate history.

  3. Raising the one-sun conversion efficiency of III-V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions

    Science.gov (United States)

    Essig, Stephanie; Allebé, Christophe; Remo, Timothy; Geisz, John F.; Steiner, Myles A.; Horowitz, Kelsey; Barraud, Loris; Ward, J. Scott; Schnabel, Manuel; Descoeudres, Antoine; Young, David L.; Woodhouse, Michael; Despeisse, Matthieu; Ballif, Christophe; Tamboli, Adele

    2017-09-01

    Today's dominant photovoltaic technologies rely on single-junction devices, which are approaching their practical efficiency limit of 25-27%. Therefore, researchers are increasingly turning to multi-junction devices, which consist of two or more stacked subcells, each absorbing a different part of the solar spectrum. Here, we show that dual-junction III-V//Sidevices with mechanically stacked, independently operated III-V and Si cells reach cumulative one-sun efficiencies up to 32.8%. Efficiencies up to 35.9% were achieved when combining a GaInP/GaAs dual-junction cell with a Si single-junction cell. These efficiencies exceed both the theoretical 29.4% efficiency limit of conventional Si technology and the efficiency of the record III-V dual-junction device (32.6%), highlighting the potential of Si-based multi-junction solar cells. However, techno-economic analysis reveals an order-of-magnitude disparity between the costs for III-V//Si tandem cells and conventional Si solar cells, which can be reduced if research advances in low-cost III-V growth techniques and new substrate materials are successful.

  4. The Jovian period in the Sun?

    Science.gov (United States)

    Kotov, V. A.

    2015-09-01

    The 41-year measurements of the Doppler effect of the photosphere performed at the Crimean Astrophysical Observatory, discovered two periods of global oscillations of the Sun: 9600.606(12) s and 9597.929(15) s. Their beat period, 398.4(2.9) d, well agrees with a synodic orbital period of Jupiter, PJ = 398.9 d, raising a new problem for solar physics, cosmogony and cosmology. A hypothesis is advanced that the PJ beating of the Sun is induced by gravitation of Jupiter, revolving in a privileged reference system "the Sun - the Earth".

  5. Monitoring Holes in the Sun's Corona

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Coronal holes are where the fast solar wind streams out of the Suns atmosphere, sending charged particles on rapid trajectories out into the solar system. A new study examines how the distribution of coronal holes has changed over the last 40 years.Coronal holes form where magnetic field lines open into space (B) instead of looping back to the solar surface (A). [Sebman81]Source of the Fast Solar WindAs a part of the Suns natural activity cycle, extremely low-density regions sometimes form in the solar corona. These coronal holes manifest themselves as dark patches in X-ray and extreme ultraviolet imaging, since the corona is much hotter than the solar surface that peeks through from underneath it.Coronal holes form when magnetic field lines open into space instead of looping back to the solar surface. In these regions, the solar atmosphere escapes via these field lines, rapidly streaming away from the Suns surface in whats known as the fast solar wind.Coronal Holes Over Space and TimeAutomated detection of coronal holes from image-based analysis is notoriously difficult. Recently, a team of scientists led by Kenichi Fujiki (ISEE, Nagoya University, Japan) has developed an automated prediction technique for coronal holes that relies instead on magnetic-field data for the Sun, obtained at the National Solar Observatorys Kitt Peak between 1975 and 2014. The team used these data to produce a database of 3335 coronal hole predictions over nearly 40 years.Latitude distribution of 2870 coronal holes (each marked by an x; color indicates polarity), overlaid on the magnetic butterfly map of the Sun. The low-latitude coronal holes display a similar butterfly pattern, in which they move closer to the equator over the course of the solar cycle. Polar coronal holes are more frequent during solar minima. [Fujiki et al. 2016]Examining trends in the coronal holes distribution in latitude and time, Fujiki and collaborators find a strong correlation between the total area covered

  6. Hot air from the sun. Domestic heating with air-filled solar collectors; Warme Luft von der Sonne. Luftkollektoren heizen Wohnhaeuser

    Energy Technology Data Exchange (ETDEWEB)

    Brake, M. [Redaktion Sonnenenergie (Germany)

    2006-09-15

    Air-filled solar collectors have been used successfully in industrial and office buildings for many years. With the spread of low-energy buildings, they are also becoming an interesting technology for domestic heating. They have the advantage of direct integration in the architectural concept of a building and direct solar heating of room air. Synergy effects are achieved by combining them with PV systems, ventilation systems, or service water heating systems. (orig.)

  7. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  8. The Sun is Condensed Matter and has a Real Surface

    Science.gov (United States)

    Robitaille, Pierre-Marie

    2014-03-01

    The idea that the Sun was a gaseous in nature was born from 1858-65. At that time, a group of men, including Herbert Spencer, Father Angelo Secchi, Warren de la Rue, Balfour Stewart, and Benjamin Loewy, advanced that the Sun was a ball of gas. In 1865, Hervé Faye was the first to argue that the solar surface was merely an illusion. Dismissing all signs to the contrary, solar physics has promoted this idea to the present day, as manifested by the Standard Solar Model. In this work, overwhelming observational evidence will be presented that the Sun does indeed possess a distinct surface (see P.M. Robitaille, Forty Lines of Evidence for Condensed Matter -- The Sun on Trial: Liquid Metallic Hydrogen as a Solar Building Block, Progress in Physics, 2013, v. 4, 90-143). Our telescopes and satellites are sampling real structures on the surface of the Sun.

  9. The Sun and How to Observe It

    CERN Document Server

    Jenkins, Jamey L

    2009-01-01

    Without the Sun, all life on Earth would perish. But what exactly do we know about this star that lights, heats, and powers Earth? Actually, we know quite a lot, thanks mainly to a host of eager solar observers. Looking directly at the Sun is EXTREMELY hazardous. But many astronomers, both professional and amateur, have found ways to view the Sun safely to learn about it. You, too, can view the Sun in all of its glorious detail. Some of the newest, most exciting telescopes on the market are affordable to amateur astronomers or even just curious sky watchers, and with this guide to what the Sun has to offer, including sunspots, prominences, and flares, plus reviews of the latest instruments for seeing and capturing images of the Sun, you can contribute to humankind’s knowledge of this immense ball of glowing gases that gives us all life. For a complete guide to Sun viewing, see also Total Solar Eclipses and How to Observe Them (2007) by Martin Mobberley in this same series.

  10. Sun-Earth Day: Growth and Impact of NASA E/PO Program

    Science.gov (United States)

    Hawkins, I.; Thieman, J.

    2004-12-01

    Over the past six years, the NASA Sun-Earth Connection Education Forum has sponsored and coordinated education public outreach events to highlight NASA Sun-Earth Connection research and discoveries. Our strategy involves using celestial phenomena, such as total solar eclipses and the Transit of Venus to celebrate Sun-Earth Day, a popular Education and Public Outreach international program. Sun-Earth Day also focuses attention on Equinoxes and Solstices 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, Maryland Science Center, NASA Connect, Sun-Earth Connection missions, Ideum, and others, we produce webcasts, other multi-media, and print resources for use by school and informal educators nation-wide. 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. We will report lessons learned from several years of experience, and strategies for growth and sustainability. We will also share our plans for "Ancient Observatories - Timeless Knowledge" our theme for Sun-Earth Day 2005, which will feature solar alignments at ancient sites that mark the equinoxes and/or solstices. The video and webcast programming will feature several sites including: Chaco Canyon (New Mexico), Hovenweep (Utah), and Chichen Itza (Mexico). Many of these sites present unique opportunities to develop authentic cultural connections to Native Americans, highlighting the importance of the Sun across the ages.

  11. Development of Solar Research

    Science.gov (United States)

    Wittmann, Axel D.; Wolfschmidt, Gudrun; Duerbeck, Hilmar W.

    Originally based on a workshop on “Development of Solar Research”, held in Freiburg/Breisgau, this book contains articles on megalithic structures, the Nebra sky-disk, ancient sun cults, the observation of sunspots, the photography of the sun during eclipses, eclipse maps and expeditions, solar telescopes, solar physics during the Nazi era, archives of solar observations, scientific ballooning for solar research, site-testing on the Canary Islands, as well as on international cooperation.

  12. Solar heating and hot water system installed at the Senior Citizen Center, Huntsville, Alabama. [Includes engineering drawings

    Energy Technology Data Exchange (ETDEWEB)

    1980-02-01

    Information is provided on the solar energy system installed at the Huntsville Senior Citizen Center. The solar space heating and hot water facility and the project involved in its construction are described in considerable detail and detailed drawings of the complete system and discussions of the planning, the hardware, recommendations, and other pertinent information are included. The facility was designed to provide 85 percent of the hot water and 85 percent of the space heating requirements. Two important factors concerning this project for commercial demonstration are the successful use of silicon oil as a heat transfer fluid and the architecturally aesthetic impact of a large solar energy system as a visual centerpoint. There is no overheat or freeze protection due to the characteristics of the silicon oil and the design of the system. Construction proceeded on schedule with no cost overruns. It is designed to be relatively free of scheduled maintenance, and has experienced practically no problems.

  13. Sun and Sun Worship in Different Cultures

    Science.gov (United States)

    Farmanyan, S. V.; Mickaelian, A. M.

    2014-10-01

    The Sun symbol is found in many cultures throughout history, it has played an important role in shaping our life on Earth since the dawn of time. Since the beginning of human existence, civilisations have established religious beliefs that involved the Sun's significance to some extent. As new civilisations and religions developed, many spiritual beliefs were based on those from the past so that there has been an evolution of the Sun's significance throughout cultural development. For comparing and finding the origin of the Sun we made a table of 66 languages and compared the roots of the words. For finding out from where these roots came from, we also made a table of 21 Sun Gods and Goddesses and proved the direct crossing of language and mythology.

  14. Further Analyses of the NASA Glenn Research Center Solar Cell and Photovoltaic Materials Experiment Onboard the International Space Station

    Science.gov (United States)

    Myers, Matthew G.; Prokop, Norman F.; Krasowski, Michael J.; Piszczor, Michael F.; McNatt, Jeremiah S.

    2016-01-01

    Accurate air mass zero (AM0) measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. The NASA Glenn Research Center (GRC) has flown an experiment designed to measure the electrical performance of several solar cells onboard NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4) on the exterior of the International Space Station (ISS). Four industry and government partners provided advanced PV devices for measurement and orbital environment testing. The experiment was positioned on the exterior of the station for approximately eight months, and was completely self-contained, providing its own power and internal data storage. Several new cell technologies including four-junction (4J) Inverted Metamorphic Multi-Junction (IMM) cells were evaluated and the results will be compared to ground-based measurement methods.

  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. The Sun in Time: Activity and Environment

    Directory of Open Access Journals (Sweden)

    Güdel Manuel

    2007-12-01

    Full Text Available The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels, its faster rotation generated enhanced magnetic activity; magnetic heating processes in the chromosphere, the transition region, and the corona induced ultraviolet, extreme-ultraviolet, and X-ray emission about 10, 100, and 1000 times, respectively, the present-day levels, as inferred from young solar-analog stars. Also, the production rate of accelerated, high-energy particles was orders of magnitude higher than in present-day solar flares, and a much stronger wind escaped from the Sun, permeating the entire solar system. The consequences of the enhanced radiation and particle fluxes from the young Sun were potentially severe for the evolution of solar-system planets and moons. Interactions of high-energy radiation and the solar wind with upper planetary atmospheres may have led to the escape of important amounts of atmospheric constituents. The present dry atmosphere of Venus and the thin atmosphere of Mars may be a product of early irradiation and heating by solar high-energy radiation. High levels of magnetic activity are also inferred for the pre-main sequence Sun. At those stages, interactions of high-energy radiation and particles with the circumsolar disk in which planets eventually formed were important. Traces left in meteorites by energetic particles and anomalous isotopic abundance ratios in meteoritic inclusions may provide evidence for a highly active pre-main sequence Sun. The present article reviews these various issues related to the magnetic activity of the young Sun and the consequent interactions with its environment. The emphasis is on the phenomenology related to the production of high-energy photons and particles. Apart from the activity on the young Sun, systematic trends applicable to the entire

  17. SunShot Initiative Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    DOE Solar Energy Technologies Office

    2015-04-01

    The U.S. Department of Energy (DOE) SunShot Initiative is a collaborative national effort launched in 2011 that aggressively drives innovation to make solar energy fully cost competitive with traditional energy sources before the end of the decade. The SunShot fact sheet outlines goals and successes of the program as it works with private companies, universities, non-profit organizations, state and local governments, and national laboratories to drive down the cost of solar electricity to $0.06 per kilowatt-hour, without incentives, by the year 2020.

  18. The Solar Energy Consortium of New York Photovoltaic Research and Development Center

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Petra M.

    2012-10-15

    Project Objective: To lead New York State to increase its usage of solar electric systems. The expected outcome is that appropriate technologies will be made available which in turn will help to eliminate barriers to solar energy usage in New York State. Background: The Solar Energy Consortium has been created to lead New York State research on solar systems specifically directed at doubling the efficiency, halving the cost and reducing the cost of installation as well as developing unique form factors for the New York City urban environment.

  19. SESC (Space Environment Services Center) glossary of solar-terrestrial terms (2nd edition)

    Energy Technology Data Exchange (ETDEWEB)

    1988-08-01

    Contents include: Glossary of solar-terrestrial terms; Appendix A: Acronyms and initialisms; Appendix B: Units; Appendix C: Modified zurich (McIntosh) sunspot classification; Appendix D: Bibliography.

  20. Estudo de distribuição e morfologia dos melanócitos em pele com e sem exposição solar Melanocytes distribution and morphology analysis in skin with and without sun exposure

    Directory of Open Access Journals (Sweden)

    Daniela Mayumi Takano

    2010-02-01

    Full Text Available INTRODUÇÃO E OBJETIVOS: Acredita-se que a exposição solar possa alterar número, distribuição e morfologia dos melanócitos na pele humana, muitas vezes dificultando a interpretação de biópsias de pele, principalmente para o diagnóstico de lesões melanocíticas iniciais e para a avaliação precisa de margens de ressecção. O objetivo deste trabalho foi avaliar os melanócitos da pele humana em área exposta e não exposta ao sol. MÉTODOS: Realizada análise histológica de 60 fragmentos de biópsias de pele obtidas do antebraço (área fotoexposta e região glútea (área coberta de cadáveres do Serviço de Verificação de Óbitos de Recife-PE. A estatística foi realizada com o SPSS Windows versão 12.0. RESULTADOS: Observou-se um número bastante variável de melanócitos nos fragmentos de pele, com maior concentração destes na região do antebraço (área de maior fotoexposição (p INTRODUCTION AND OBJECTIVES: It is believed that sun exposure can change the number, distribution and morphology of melanocytes in human skin, which often hinders the interpretation of skin biopsies, mainly as to diagnosis of initial melanocytic lesions and accurate assessment of resection margins. Our objective was to evaluate melanocytes in sun-exposed and non-exposed skin. METHODS: It was conducted the histological analysis of 60 skin biopsy samples resected from cadaver forearm (sun-exposed skin and cadaver buttock (non-exposed skin from the Death Verification Service (Serviço de Verificação de Óbitos of Recife, state of Pernambuco. The statistical analysis was performed with SPSS Windows version 12.0. RESULTS: There was considerable variability in melanocyte density, with a higher concentration of these cells in sun-exposed areas (p < 0.001. There was also an irregular distribution of melanocytes along the epidermal basal layer, occasionally with cells arranged side by side. This confluence was identified with a higher frequency in sun

  1. Sun's rap song

    Science.gov (United States)

    Hogan, M.; Lee, W.

    1995-07-01

    We present a rap song composed for the Sun, our star. This Sun's Rap Song can be utilized in classroom teaching to spark the students' interest and facilitate the students' learning of the relevant subjects.

  2. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  3. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  4. Coating Processes Boost Performance of Solar Cells

    Science.gov (United States)

    2012-01-01

    NASA currently has spacecraft orbiting Mercury (MESSENGER), imaging the asteroid Vesta (Dawn), roaming the red plains of Mars (the Opportunity rover), and providing a laboratory for humans to advance scientific research in space (the International Space Station, or ISS). The heart of the technology that powers those missions and many others can be held in the palm of your hand - the solar cell. Solar, or photovoltaic (PV), cells are what make up the panels and arrays that draw on the Sun s light to generate electricity for everything from the Hubble Space Telescope s imaging equipment to the life support systems for the ISS. To enable NASA spacecraft to utilize the Sun s energy for exploring destinations as distant as Jupiter, the Agency has invested significant research into improving solar cell design and efficiency. Glenn Research Center has been a national leader in advancing PV technology. The Center s Photovoltaic and Power Technologies Branch has conducted numerous experiments aimed at developing lighter, more efficient solar cells that are less expensive to manufacture. Initiatives like the Forward Technology Solar Cell Experiments I and II in which PV cells developed by NASA and private industry were mounted outside the ISS have tested how various solar technologies perform in the harsh conditions of space. While NASA seeks to improve solar cells for space applications, the results are returning to Earth to benefit the solar energy industry.

  5. Control of the Earth's electric field intensity through solar wind modulation of galactic cosmic radiation: Support for a proposed atmospheric electrical sun-weather mechanism

    Science.gov (United States)

    Markson, R.

    1980-01-01

    The ionospheric potential and galactic cosmic radiation, found to be inversely correlated with the solar wind velocity are examined as being germane to weather modification. Since the ionospheric potential is proportional to the fair weather electric field intensity and cosmic radiation is the dominant source of atmospheric ionization, it is concluded that the Earth's overall electric field varies in phase with atmospheric ionization and that the latter is modulated by the solar wind. A proposed mechanism, in which solar control of ionizing radiation influences atmospheric electrification and thus possibly cloud physical processes is discussed. An experimental approach to critically test the proposed mechanism through comparison of the temporal variation of the Earth's electric field with conditions in the interplanetary medium is outlined.

  6. Direct effect of aerosol on incident solar radiation at the surface as a function of aerosol mixtures measured in the center of Rome.

    Science.gov (United States)

    Campanelli, M.; Bassani, C.; Cacciani, M.; Siani, A. M.; Perrino, C.; Canepari, S.; Di Sarra, A.; Salzano, R.; Casasanta, G. P.; Tirelli, C.; Estelles, V.

    2012-04-01

    Aerosols determine a radiative effect in the atmosphere by affecting the amount of solar radiation reaching the surface and then acting on the temperature of both the layer where they are located and the surface. The presence of very absorbent particles typical of the urban environment, is therefore dangerous not only for human health but also because they are able to increase the temperature of the atmospheric layer in which they are located interacting with the "heath island" phenomenon. The resulting variation of both surface temperature and temperature vertical profile influences the dilution of atmospheric pollutants and needs to be studied in more detail, particularly in the summer period when heat waves are more frequent. Chemical analysis of surface particulate matter performed at the urban site of Rome (Perrino et al. 2009) showed that sea salt, locally produced urban aerosol and desert dust can be recognized depending on the intensity of the episodes transporting different particles types. As a result: i) the direct effect of aerosol at the surface change as a function of aerosol mixtures; ii) the variation of incident solar radiation affects the local convective air motion modifying the low level circulation and having an effect on the particles deposition and hence on the chemical characterization of the mixture. On the base of above issues a day-time intensive field campaign was held in Rome (Italy) in June and July 2011 at the University of Rome, La Sapienza, located in the city center (lat 41.9°N, long 12.5 °E). Chemical analysis of the aerosol particles was performed on particulate collected by PM10 collectors. Columnar aerosol optical and physical properties in clear sky were retrieved by using a PREDE sun-sky radiometer, part of ESR/SKYNET network. Vertical profiles of aerosol were obtained by a Lidar and incoming total solar radiation was measured by a Black and White Pyranometer . A Brewer spectrophotometer, a Sodar, and a MFRSR provided

  7. Seasons by the Sun

    Science.gov (United States)

    Stark, Meri-Lyn

    2005-01-01

    Understanding the Sun has challenged people since ancient times. Mythology from the Greek, Inuit, and Inca cultures attempted to explain the daily appearance and nightly disappearance of the Sun by relating it to a chariot being chased across the sky. While people no longer believe the Sun is a chariot racing across the sky, teachers are still…

  8. Personal, Seasonal Suns

    Science.gov (United States)

    Sutley, Jane

    2010-01-01

    This article presents an art project designed for upper-elementary students to (1) imagine visual differences in the sun's appearance during the four seasons; (2) develop ideas for visually translating their personal experiences regarding the seasons to their sun drawings; (3) create four distinctive seasonal suns using colors and imagery to…

  9. NREL, CSEM Jointly Set New Efficiency Record with Dual-Junction Solar Cell

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-01

    Scientists set a new world record for converting non-concentrated sunlight into electricity using a dual-junction III-V/Si solar cell. National Renewable Energy Laboratory (NREL) and Swiss Center for Electronics and Microtechnology (CSEM) scientists have collaborated to create a novel tandem solar cell that operates at 29.8% conversion efficiency under non-concentrator (1-sun) conditions. In comparison, the 1-sun efficiency of a silicon (Si) single-junction solar cell is probably still a few years away from converging on its practical limit of about 26%.

  10. Solar energy engineering

    Energy Technology Data Exchange (ETDEWEB)

    Sayigh, A.A.M. (ed.)

    1977-01-01

    The scope and advantages of solar energy are dealt with. The nature of the sun, the solar radiation spectrum, the estimation of total, direct, and diffuse radiation, and the heat transfer fundamentals for solar energy application are explained. The fundamentals, fabrication, and uses of various water and air heaters are outlined. Optics and concentrating collectors are dealt with, as well as solar furnaces. The various applications of solar energy are discussed, namely, solar pond, solar distillation, photovoltaic conversion of solar energy, solar refrigeration, solar hydrogen production, space applications, and solar measuring equipment. The cost of solar appliances is discussed. (MHR)

  11. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  12. NASA Solar Array Demonstrates Commercial Potential

    Science.gov (United States)

    Creech, Gray

    2006-01-01

    A state-of-the-art solar-panel array demonstration site at NASA's Dryden Flight Research Center provides a unique opportunity for studying the latest in high-efficiency solar photovoltaic cells. This five-kilowatt solar-array site (see Figure 1) is a technology-transfer and commercialization success for NASA. Among the solar cells at this site are cells of a type that was developed in Dryden Flight Research Center s Environmental Research Aircraft and Sensor Technology (ERAST) program for use in NASA s Helios solar-powered airplane. This cell type, now denoted as A-300, has since been transferred to SunPower Corporation of Sunnyvale, California, enabling mass production of the cells for the commercial market. High efficiency separates these advanced cells from typical previously commercially available solar cells: Whereas typical previously commercially available cells are 12 to 15 percent efficient at converting sunlight to electricity, these advanced cells exhibit efficiencies approaching 23 percent. The increase in efficiency is due largely to the routing of electrical connections behind the cells (see Figure 2). This approach to increasing efficiency originated as a solution to the problem of maximizing the degree of utilization of the limited space available atop the wing of the Helios airplane. In retrospect, the solar cells in use at this site could be used on Helios, but the best cells otherwise commercially available could not be so used, because of their lower efficiencies. Historically, solar cells have been fabricated by use of methods that are common in the semiconductor industry. One of these methods includes the use of photolithography to define the rear electrical-contact features - diffusions, contact openings, and fingers. SunPower uses these methods to produce the advanced cells. To reduce fabrication costs, SunPower continues to explore new methods to define the rear electrical-contact features. The equipment at the demonstration site includes

  13. Absolute spectral radiance responsivity calibration of sun photometers

    Energy Technology Data Exchange (ETDEWEB)

    Xu Qiuyun; Zheng Xiaobing; Zhang Wei; Wang Xianhua; Li Jianjun; Li Xin [Key Laboratory of Optical Calibration and Characterization, Chinese Academy of Sciences, Hefei 230031 (China); Li Zhengqiang [Laboratoire d' Optique Atmospherique, Universite Lille 1, Villeneuve d' Ascq 59655 (France) and State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100101 (China)

    2010-03-15

    Sun photometers are designed to measure direct solar irradiance and diffused sky radiance for the purpose of atmospheric parameters characterization. A sun photometer is usually calibrated by using a lamp-illuminated integrating sphere source for its band-averaged radiance responsivity, which normally has an uncertainty of 3%-5% at present. Considering the calibration coefficients may also change with time, a regular high precision calibration is important to maintain data quality. In this paper, a tunable-laser-based facility for spectral radiance responsivity calibration has been developed at the Key Laboratory of Optical Calibration and Characterization, Chinese Academy of Sciences. A reference standard radiance radiometer, calibrated against cryogenic radiometer, is used to determine the radiance from a laser-illuminated integrating sphere source. Spectral radiance responsivity of CIMEL CE318-2 sun photometer is calibrated using this new calibration system with a combined standard uncertainty of about 0.8%. As a validation, the derived band-averaged radiance responsivity are compared to that from a Goddard Space Flight Center lamp-based sphere calibration and good agreements (difference <1.4%) are found from 675 to 1020 nm bands.

  14. Absolute spectral radiance responsivity calibration of sun photometers.

    Science.gov (United States)

    Xu, Qiuyun; Zheng, Xiaobing; Li, Zhengqiang; Zhang, Wei; Wang, Xianhua; Li, Jianjun; Li, Xin

    2010-03-01

    Sun photometers are designed to measure direct solar irradiance and diffused sky radiance for the purpose of atmospheric parameters characterization. A sun photometer is usually calibrated by using a lamp-illuminated integrating sphere source for its band-averaged radiance responsivity, which normally has an uncertainty of 3%-5% at present. Considering the calibration coefficients may also change with time, a regular high precision calibration is important to maintain data quality. In this paper, a tunable-laser-based facility for spectral radiance responsivity calibration has been developed at the Key Laboratory of Optical Calibration and Characterization, Chinese Academy of Sciences. A reference standard radiance radiometer, calibrated against cryogenic radiometer, is used to determine the radiance from a laser-illuminated integrating sphere source. Spectral radiance responsivity of CIMEL CE318-2 sun photometer is calibrated using this new calibration system with a combined standard uncertainty of about 0.8%. As a validation, the derived band-averaged radiance responsivity are compared to that from a Goddard Space Flight Center lamp-based sphere calibration and good agreements (difference <1.4%) are found from 675 to 1020 nm bands.

  15. Application of Combing the Solar Energy and Noise Reduction in the Outdoor Sun-Shading Louver%太阳能减噪结合板在建筑室外遮阳百叶中的应用研究

    Institute of Scientific and Technical Information of China (English)

    阎国鹏; 敖永安; 许志鹏; 郝亚芬; 邱峰

    2014-01-01

    The study is aimed to apply the solar panel combined with the PVC noise reduction hole board into the outdoor sun-shading louver so that it could improve the light environment and sound envi-ronment of the building and reduce the energy consumption. The sun-shading louver composing of the solar panel and PVC noise reduction hole board installed in the existing buildings is tested, compared with the original building, and analyzing its effects of energy efficiency and noise reduction performance. Through comparing the effects of energy efficiency with or without the sun-shading louver set, it found that in Bei-jing area, under the certain structure, every 100 square meters of solar panel can save 1.52 tons of standard coal, while the noise reduction board can reduce 10%~20% noise indoor. The result shows that the certain structure of the outdoor sun-shading louvers can decrease some sunlight from outdoor into indoor in sum-mer and reduce the noise from outdoor while providing the necessary sunshine in winter. The structure is simple and durable, while it can reduce the load of heating and air-conditioning and save energy.%将太阳能光电转换板与PVC减噪孔板结合应用于建筑遮阳百叶中,在改善建筑光环境的同时对建筑声环境与能耗有所改善。在已有建筑中,将太阳能光电转换板与PVC减噪孔板结合构成建筑遮阳百叶的叶片,在保证系统遮阳性能的条件下,与原有建筑对比测试,分析太阳能减噪结合板节能效益和减噪性能。通过对比遮阳板设置前后得到太阳能减噪结合板的节能效益,发现在北京地区在一定的设计结构下,每使用100 m2太阳能光电转换板能节约1.52吨标准煤,减噪板能减少10%~20%的室内噪音。一定结构的太阳能减噪结合板遮阳百叶可减少夏季进入室内的阳光,能保证冬季必要日照的同时减少进入建筑室内的噪音;结构简单,耐用,可减少建筑供暖和空调

  16. Research on Sun-tracking Control System in Solar Photovoltaic Power and Its Design%太阳能光伏发电中跟踪控制系统的研究与设计

    Institute of Scientific and Technical Information of China (English)

    丁婷婷; 祝雪妹

    2012-01-01

    The solar energy is utilized for protecting the environment of the earth. Photovoltaic power is one way of solar power utilization. It is very important to further improve the efficiency of its device. This is an important question which has need to be solved at present. Through researching on its tracking control system which is widely used, the feed-forward and closed-loop control tracking scheme is proposed to improve the tracking efficiency of solar photovoltaic panel. The solar photovoltaic panel rotation angle for the feed-forward track is obtained according to the trajectory of the sun. The photoelectric sensor is used to detect the photoelectric signal for the closed-loop control of solar photovoltaic panel, so that the errors of the tracking devices of solar photovoltaic panel are o-vercome during the installing, production and processing and the tracking control accuracy is improved greatly.%太阳能的利用有利于世界的环境保护,光伏发电作为太阳能发电的方式之一,无论从科技应用还是从商业开发的角度出发,如何更进一步地提高太阳能光伏发电装置的效率,都是目前有待解决的重要问题.针对目前应用广泛的太阳能光伏发电跟踪控制系统进行了研究,为了提高太阳能光伏板的跟踪效率,提出了前馈加闭环的跟踪控制方案.根据太阳的运动轨迹计算出太阳能光伏板理论上需转动的角度,实现前馈上的跟踪控制;采用光电传感器,将检测到的光电信号作为反馈,实现光伏板的闭环跟踪控制,克服了太阳能光伏发电跟踪控制系统在安装、生产、加工过程中存在的误差,提高了跟踪控制的精度.

  17. Neptune as a Mirror for the Sun

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    How would the Kepler mission see a star like the Sun? We now know the answer to this question due to a creative approach: a new study has used the Kepler K2 mission to detect signals from the Sun reflected off of the surface of Neptune.Asteroseismology uses different oscillation modes of a star to probe its internal structure and properties. [Tosaka]Information in OscillationsKeplers most glamorous work is in discovering new planets around other stars. To successfully do this, however, the spacecraft is also quietly doing a lot of very useful work in the background, characterizing the many stars in our vicinity that planets might be found around.One of the ways Kepler gets information about these stars is from oscillations of the stars intensities. In asteroseismology, we look at oscillatory modes that are caused by convection-driven pressure changes on the inside of the star. All stars with near-surface convection oscillate like this including the Sun and by measuring the oscillations in intensity of these stars, we can make inferences about the stars properties.A Planetary MirrorWe do this by first understanding our Suns oscillations especially well (made easier by the fact that its nearby!). Then we use asteroseimic scaling relations determined empirically that relate characteristics like mass and radius of other stars to those of the Sun, based on the relation between the stars oscillation properties to the Suns.The trouble is, those oscillation properties are difficult to measure, and different instruments often measure different values. For this reason, wed like to measure the Suns oscillations with the same instrument we use to measure other stars oscillations: Kepler.Top panel: Kepler K2 49-day light curve of Neptune. Bottom panel: power density spectrum as a function of frequency (grey). Neptunes rotation frequencies and harmonics appear toward the left side (blue); the excess power due to the solar modes is visible toward the bottom right. The green curve

  18. Stimulated Radiative Molecular Association in the Early Solar System. II. Orbital Radii of the Planets and Other Satellites of the Sun

    CERN Document Server

    Lombardi, James C

    2015-01-01

    In a previous investigation, the orbital radii of regular satellites of Uranus, Jupiter, Neptune, and Saturn are shown to be directly related to photon energies in the spectra of atomic and molecular hydrogen. To explain these observations a model was developed involving stimulated radiative molecular association (SRMA) reactions among photons and atoms in the protosatellite disks of the planets. In the present investigation, the previously developed model is applied to the planets and important satellites of the Sun. A key component of the model involves resonance associated with SRMA. Through this resonance, thermal energy is extracted from the protosun's protoplanetary disk at specific distances from the protosun wherever there is a match between the local thermal energy of the disk and the energy of photons impinging on the disk. Orbital radii of the planets and satellites are related to photon energies ($E_P$ values) in the spectrum of atomic hydrogen. An expression determined previously is used to relat...

  19. THE UBV(RI){sub C} COLORS OF THE SUN

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, I. [McDonald Observatory and Department of Astronomy, University of Texas at Austin, 1 University Station, C1400 Austin, TX 78712-0259 (United States); Michel, R.; Schuster, W. J. [Observatorio Astronomico Nacional, Universidad Nacional Autonoma de Mexico, Apartado Postal 877, Ensenada, B.C., CP 22800 (Mexico); Sefako, R.; Van Wyk, F. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Tucci Maia, M. [UNIFEI, DFQ-Instituto de Ciencias Exatas, Universidade Federal de Itajuba, Itajuba MG (Brazil); Melendez, J. [Departamento de Astronomia do IAG/USP, Universidade de Sao Paulo, Rua do Matao 1226, Sao Paulo, 05508-900 SP (Brazil); Casagrande, L. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching (Germany); Castilho, B. V. [Laboratorio Nacional de Astrofisica/MCT, Rua Estados Unidos 154, 37504-364 Itajuba, MG (Brazil)

    2012-06-10

    Photometric data in the UBV(RI){sub C} system have been acquired for 80 solar analog stars for which we have previously derived highly precise atmospheric parameters T{sub eff}, log g, and [Fe/H] using high-resolution, high signal-to-noise ratio spectra. UBV and (RI){sub C} data for 46 and 76 of these stars, respectively, are published for the first time. Combining our data with those from the literature, colors in the UBV(RI){sub C} system, with {approx_equal} 0.01 mag precision, are now available for 112 solar analogs. Multiple linear regression is used to derive the solar colors from these photometric data and the spectroscopically derived T{sub eff}, log g, and [Fe/H] values. To minimize the impact of systematic errors in the model-dependent atmospheric parameters, we use only the data for the 10 stars that most closely resemble our Sun, i.e., the solar twins, and derive the following solar colors: (B - V){sub Sun} = 0.653 {+-} 0.005, (U - B){sub Sun} = 0.166 {+-} 0.022, (V - R){sub Sun} = 0.352 {+-} 0.007, and (V - I){sub Sun} = 0.702 {+-} 0.010. These colors are consistent, within the 1{sigma} errors, with those derived using the entire sample of 112 solar analogs. We also derive the solar colors using the relation between spectral-line-depth ratios and observed stellar colors, i.e., with a completely model-independent approach, and without restricting the analysis to solar twins. We find (B - V){sub Sun} = 0.653 {+-} 0.003, (U - B){sub Sun} = 0.158 {+-} 0.009, (V - R){sub Sun} = 0.356 {+-} 0.003, and (V - I){sub Sun} = 0.701 {+-} 0.003, in excellent agreement with the model-dependent analysis.

  20. Solar thermal activation study of the Land of Hessen. Study on solar options for municipal swimming pools, gymnasia and sports centers in Hessen. Solarthermische Aktivierungsstudie Hessen. Studie zur solaren Eignung von kommunalen Freibaedern sowie Turn- und Sporthallen in Hessen

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    This study is to give communities and districts in the Land of Hessen a decision aid on whether solar service water or pool water heating would be an economically efficient alternative in numerical swimming pools or sports centers. (orig.)

  1. International Sun-Earth Explorer (ISEE)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Series of three US satellites designed to study the solar wind and its interaction with the Earth's magnetosphere. ISEE-1 and 2 were placed into highly elliptical Earth orbits. ISEE-3 was placed in a halo orbit at the L1 Lagrangian point between the Sun and Earth. It gave advance warning of solar storms heading towards Earth. (See also INTERNATIONAL COMETARY EXPLORER and EXPLORER.)...

  2. Complete Solution of Sun Tracking for Heliostat

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-Tian; LIM Boon-Han; LIM Chern-Sing

    2006-01-01

    A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuthelevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general solution and its significance in solar energy engineering are discussed.

  3. Complete Solution of Sun Tracking for Heliostat

    Science.gov (United States)

    Chen, Ying-Tian; Lim, Boon-Han; Lim, Chern-Sing

    2006-01-01

    A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuth-elevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general solution and its significance in solar energy engineering are discussed.

  4. Observing the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping

    Science.gov (United States)

    White, S. M.; Iwai, K.; Phillips, N. M.; Hills, R. E.; Hirota, A.; Yagoubov, P.; Siringo, G.; Shimojo, M.; Bastian, T. S.; Hales, A. S.; Sawada, T.; Asayama, S.; Sugimoto, M.; Marson, R. G.; Kawasaki, W.; Muller, E.; Nakazato, T.; Sugimoto, K.; Brajša, R.; Skokić, I.; Bárta, M.; Kim, S.; Remijan, A. J.; de Gregorio, I.; Corder, S. A.; Hudson, H. S.; Loukitcheva, M.; Chen, B.; De Pontieu, B.; Fleishmann, G. D.; Gary, D. E.; Kobelski, A.; Wedemeyer, S.; Yan, Y.

    2017-07-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute temperature scale is a critical measurement for much of ALMA solar science, including the understanding of energy transfer through the solar atmosphere, the properties of prominences, and the study of shock heating in the chromosphere. In order to provide an absolute temperature scale, ALMA solar observing will take advantage of the remarkable fast-scanning capabilities of the ALMA 12 m dishes to make single-dish maps of the full Sun. This article reports on the results of an extensive commissioning effort to optimize the mapping procedure, and it describes the nature of the resulting data. Amplitude calibration is discussed in detail: a path that uses the two loads in the ALMA calibration system as well as sky measurements is described and applied to commissioning data. Inspection of a large number of single-dish datasets shows significant variation in the resulting temperatures, and based on the temperature distributions, we derive quiet-Sun values at disk center of 7300 K at λ = 3 mm and 5900 K at λ = 1.3 mm. These values have statistical uncertainties of about 100 K, but systematic uncertainties in the temperature scale that may be significantly larger. Example images are presented from two periods with very different levels of solar activity. At a resolution of about 25'', the 1.3 mm wavelength images show temperatures on the disk that vary over about a 2000 K range. Active regions and plages are among the hotter features, while a large sunspot umbra shows up as a depression, and filament channels are relatively cool. Prominences above the solar limb are a common feature of the single-dish images.

  5. Connecting the Sun and the Solar Wind: The First Two-Dimensional Self-consistent MHD Simulation under the Alfv\\'en Wave Scenario

    CERN Document Server

    Matsumoto, Takuma

    2011-01-01

    We report the results of the first two-dimensional self-consistent simulations directly covering from the photosphere to the interplanetary space. We carefully set up grid points with spherical coordinate to treat Alfv\\'enic waves in the atmosphere with the huge density contrast, and successfully simulate hot coronal wind streaming out as a result of surface convective motion. Footpoint motion excites upwardly propagating Alfv\\'enic waves along an open magnetic flux tube. These waves, traveling in non-uniform medium, suffer reflection, nonlinear mode conversion to compressive modes, and turbulent cascade. Combination of these mechanisms, the Alfv\\'enic waves eventually dissipate to accelerate the solar wind. While the shock heating by the dissipation of the compressive wave plays a primary role in the coronal heating, both turbulent cascade and shock heating contribute to drive the solar wind.

  6. West Chester Work Center Solar Space Heating Demonstration Project. Final technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    1979-08-01

    An integrated system is described providing solar energy space heating for a 9982 sq ft, newly built, one-story building. Functionally, the building consists of two sections: an office and a storeroom. The office section is heated by solar-assisted water-to-air heat pump units. The storeroom section is heated by an air-handling unit, containing a water-to-air coil. The system design was based on solar energy providing 62% of the heating load, with the balance to be supplied by heat pump power and a back-up electric boiler. The system includes 1900 active (2112 gross) square feet of flat-plate solar collectors, and a 6000 gallon above-ground indoor storage tank. Freeze protection is provided by a gravity drain-down scheme combined with nitrogen pressurization in a closed circuit.

  7. Renovation of the solar furnace of ''Odeillo'' tests center

    Energy Technology Data Exchange (ETDEWEB)

    Suzanne, P. (ETCA, Centre d' Essais d' Odeillo, 66 - Font Romeu (France))

    1994-01-01

    The main solar furnace heliostat mirrors of the CEO becoming out of age, their whole replacement have been led. The individual adjustment of each mirror being critical, specifical optical unit and metrological procedure had to be set up in order to carry out the full operation. Ending it, a solar focal image characterization have been led and the furnace calibration could begin, allowing to evaluate the enhancement obtained after the mirrors exchange on both qualitative and quantitative parts. (author). 3 figs.

  8. High Energy Replicated Optics to Explore the Sun Balloon-Borne Telescope: Astrophysical Pointing

    Science.gov (United States)

    Gaskin, Jessica; Wilson-Hodge, Colleen; Ramsey, Brian; Apple, Jeff; Kurt, Dietz; Tennant, Allyn; Swartz, Douglas; Christe, Steven D.; Shih, Albert

    2014-01-01

    On September 21, 2013, the High Energy Replicated Optics to Explore the Sun, or HEROES, balloon-borne x-ray telescope launched from the Columbia Scientific Balloon Facility's site in Ft. Summer, NM. The flight lasted for approximately 27 hours and the observational targets included the Sun and astrophysical sources GRS 1915+105 and the Crab Nebula. Over the past year, the HEROES team upgraded the existing High Energy Replicated Optics (HERO) balloon-borne telescope to make unique scientific measurements of the Sun and astrophysical targets during the same flight. The HEROES Project is a multi-NASA Center effort with team members at both Marshall Space Flight Center (MSFC) and Goddard Space Flight Center (GSFC), and is led by Co-PIs (one at each Center). The HEROES payload consists of the hard X-ray telescope HERO, developed at MSFC, combined with several new systems. To allow the HEROES telescope to make observations of the Sun, a new solar aspect system was added to supplement the existing star camera for fine pointing during both the day and night. A mechanical shutter was added to the star camera to protect it during solar observations and two alignment monitoring systems were added for improved pointing and post-flight data reconstruction. This mission was funded by the NASA HOPE (Hands-On Project Experience) Training Opportunity awarded by the NASA Academy of Program/Project and Engineering Leadership, in partnership with NASA's Science Mission Directorate, Office of the Chief Engineer and Office of the Chief Technologist.

  9. Solar Hot Water Heater

    Science.gov (United States)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  10. Ulysses Passes South Pole of Sun

    Institute of Scientific and Technical Information of China (English)

    程林

    1995-01-01

    On the 14th of September,1994, the fastest scientific instrument in space passed the south pole of the Sun,a place where no human-made object has been before. A spaceprobe called Ulysses made the polar pass at about midday as it continued to collect data on the solar wind,a stream of high-energy sub-atomic

  11. Observing the Sun with NuSTAR

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a space telescope primarily designed to detect high-energy X-rays from faint, distant astrophysical sources. Recently, however, its occasionally been pointing much closer to home, with the goal of solving a few longstanding mysteries about the Sun.Intensity maps from an observation of a quiet-Sun region near the north solar pole and an active region just below the solar limb. The quiet-Sun data will be searched for small flares that could be heating the solar corona, and the high-altitude emission above the limb may provide clues about particle acceleration. [Adapted from Grefenstette et al. 2016]An Unexpected TargetThough we have a small fleet of space telescopes designed to observe the Sun, theres an important gap: until recently, there was no focusing telescope making solar observations in the hard X-ray band (above ~3 keV). Conveniently, there is a tool capable of doing this: NuSTAR.Though NuSTARs primary mission is to observe faint astrophysical X-ray sources, a team of scientists has recently conducted a series of observations in which NuSTAR was temporarily repurposed and turned to focus on the Sun instead.These observations pose an interesting challenge precisely because of NuSTARs extreme sensitivity: pointing at such a nearby, bright source can quickly swamp the detectors. But though the instrument cant be used to observe the bright flares and outbursts from the Sun, its the perfect tool for examining the parts of the Sun weve been unable to explore in hard X-rays before now such as faint flares, or the quiet, inactive solar surface.In a recently published study led by Brian Grefenstette (California Institute of Technology), the team describes the purpose and initial results of NuSTARs first observations of the Sun.Solar MysteriesWhat is NuSTAR hoping to accomplish with its solar observations? There are two main questions that hard X-ray observations may help to answer.How are particles accelerated in

  12. New Views of the Sun: STEREO and Hinode

    Science.gov (United States)

    Luhmann, Janet G.; Tsuneta, Saku; Bougeret, J.-L.; Galvin, Antoinette; Howard, R. A.; Kaiser, Michael; Thompson, W. T.

    The twin-spacecraft STEREO mission has now been in orbit for 1.5 years. Although the main scientific objective of STEREO is the origin and evolution of Coronal Mass Ejections (CMEs) and their heliospheric consequences, the slow decline of the previous solar cycle has provided an extraordinary opportunity for close scrutiny of the quiet corona and solar wind, including suprathermal and energetic particles. However, STEREO has also captured a few late cycle CMEs that have given us a taste of the observations and analyses to come. Images from the SECCHI investigation afforded by STEREO's separated perspectives and the heliospheric imager have already allowed us to visibly witness the origins of the slow solar wind and the Sun-to-1 AU transit of ICMEs. The SWAVES investigation has monitored the transit of interplanetary shocks in 3D while the PLASTIC and IMPACT in-situ measurements provide the 'ground truth' of what is remotely sensed. New prospects for space weather forecasting have been demonstrated with the STEREO behind spacecraft, a successful proof-of-concept test for future space weather mission designs. The data sets for the STEREO investigations are openly available through a STEREO Science Center web interface that also provides supporting information for potential users from all communities. Comet observers and astronomers, interplanetary dust researchers and planetary scientists have already made use of this resource. The potential for detailed Sun-to-Earth CME/ICME interpretations with sophisticated modeling efforts are an upcoming STEREO-Hinode partnering activity whose success we can only anticipate at this time. Since its launch in September 2006, Hinode has sent back solar images of unprecedented clarity every day. The primary purpose of this mission is a systems approach to understanding the generation, transport and ultimate dissipation of solar magnetic fields with a well-coordinated set of advanced telescopes. Hinode is equipped with three

  13. Performance of 3-Sun Mirror Modules on Sun Tracking Carousels on Flat Roof Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Fraas, Dr. Lewis [JX Crystals, Inc.; Avery, James E. [JX Crystals, Inc.; Minkin, Leonid M [ORNL; Maxey, L Curt [ORNL; Gehl, Anthony C [ORNL; Hurt, Rick A [ORNL; Boehm, Robert F [ORNL

    2008-01-01

    Commercial buildings represent a near term market for cost competitive solar electric power provided installation costs and solar photovoltaic module costs can be reduced. JX Crystals has developed a carousel sun tracker that is prefabricated and can easily be deployed on building flat roof tops without roof penetration. JX Crystals is also developing 3-sun PV mirror modules where less expensive mirrors are substituted for two-thirds of the expensive single crystal silicon solar cell surface area. Carousels each with four 3-sun modules have been set up at two sites, specifically at Oak Ridge National Lab and at the University of Nevada in Las Vegas. The test results for these systems are presented.

  14. Performance of 3-sun mirror modules on sun tracking carousels on flat roof buildings

    Science.gov (United States)

    Fraas, Lewis; Avery, James; Minkin, Leonid; Maxey, Curt; Gehl, Tony; Hurt, Rick; Boehm, Robert

    2008-08-01

    Commercial buildings represent a near term market for cost competitive solar electric power provided installation costs and solar photovoltaic module costs can be reduced. JX Crystals has developed a carousel sun tracker that is prefabricated and can easily be deployed on building flat roof tops without roof penetration. JX Crystals is also developing 3-sun PV mirror modules where less expensive mirrors are substituted for two-thirds of the expensive single crystal silicon solar cell surface area. Carousels each with four 3-sun modules have been set up at two sites, specifically at Oak Ridge National Lab and at the University of Nevada in Las Vegas. The test results for these systems are presented.

  15. Solar Position Model for use in DIORAMA

    Energy Technology Data Exchange (ETDEWEB)

    Werley, Kenneth Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-01

    The DIORAMA code requires the solar position relative to earth in order to compute GPS satellite orientation. The present document describes two functions that compute the unit vector from either the center of the Earth to the Sun or from any observer’s position to the Sun at some specified time. Another function determines if a satellite lies within the Earth’s shadow umbra. Similarly, functions determine the position of the moon and whether a satellite lies within the Moon’s shadow umbra.

  16. Low Frequency Radio Emission from the 'Quiet' Sun

    Indian Academy of Sciences (India)

    R. Ramesh

    2000-09-01

    We present observations of the 'quiet' Sun close to the recent solar minimum (Cycle 22), with the Gauribidanur radioheliograph. Our main conclusion is that coronal streamers also influence the observed radio brightness temperature.

  17. A New Way that Planets can Affect the Sun

    Science.gov (United States)

    Wolff, Charles; Patrone, Paul

    2010-01-01

    As planets orbit the Sun, the Sun also has to move to keep the total momentum of the solar system constant. The Sun's small orbital motion plus its 25 day rotation about its axis combine to invigorate some solar instabilities. Occasional convection cells at the proper phase in their short life can be strengthened by factors of two or more. This local burst of extra kinetic energy eventually reaches the surface where it can increase the intensity of solar activity. It might explain some reports in the last century of how planetary positions correlate with solar activity. This is the first effect of planets that is large enough to cause a significant response on the Sun.

  18. Solar pannels tracking systems

    Energy Technology Data Exchange (ETDEWEB)

    Manuel, P.; Maire, J.; Chollet, C.; Rohee, S.; Vialettes, J.M.

    1984-11-23

    This patent is concerned with a steering device for solar photo-pannels laid in row in order to minimize the cast shadow of each pannel on the others, while maintaining a required land use (the pannels are disposed according to a centered hexagonal lattice). The device is designed to set a whole row of pannels according to the azimuthal orientation of the sun. It is composed of a set of (at least) two side rod drives situated at each side of the row and coupled to the pannel. The pannels are moved by the action of two (or more) traction ropes.

  19. Characterization of a 6 kW high-flux solar simulator with an array of xenon arc lamps capable of concentrations of nearly 5000 suns

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Robert; Bush, Evan; Loutzenhiser, Peter, E-mail: peter.loutzenhiser@me.gatech.edu [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Haueter, Philipp [Haueter Engineering Gmbh, Rombach 5022 (Switzerland)

    2015-12-15

    A systematic methodology for characterizing a novel and newly fabricated high-flux solar simulator is presented. The high-flux solar simulator consists of seven xenon short-arc lamps mounted in truncated ellipsoidal reflectors. Characterization of spatial radiative heat flux distribution was performed using calorimetric measurements of heat flow coupled with CCD camera imaging of a Lambertian target mounted in the focal plane. The calorimetric measurements and images of the Lambertian target were obtained in two separate runs under identical conditions. Detailed modeling in the high-flux solar simulator was accomplished using Monte Carlo ray tracing to capture radiative heat transport. A least-squares regression model was used on the Monte Carlo radiative heat transfer analysis with the experimental data to account for manufacturing defects. The Monte Carlo ray tracing was calibrated by regressing modeled radiative heat flux as a function of specular error and electric power to radiation conversion onto measured radiative heat flux from experimental results. Specular error and electric power to radiation conversion efficiency were 5.92 ± 0.05 mrad and 0.537 ± 0.004, respectively. An average radiative heat flux with 95% errors bounds of 4880 ± 223 kW ⋅ m{sup −2} was measured over a 40 mm diameter with a cavity-type calorimeter with an apparent absorptivity of 0.994. The Monte Carlo ray-tracing resulted in an average radiative heat flux of 893.3 kW ⋅ m{sup −2} for a single lamp, comparable to the measured radiative heat fluxes with 95% error bounds of 892.5 ± 105.3 kW ⋅ m{sup −2} from calorimetry.

  20. Preface to the Special Issue on "Connection of Solar and Heliospheric Activities with Near-Earth Space Weather: Sun-Earth Connection"

    Directory of Open Access Journals (Sweden)

    Chin-Chun Wu Sunny W. Y. Tam

    2013-01-01

    Full Text Available This special issue of the Terrestrial, Atmospheric and Oceanic Sciences (TAO presents a small collection of the materials presented at the 2011 International Space Plasma Symposium (ISPS, held at National Cheng-Kung University (NCKU in Tainan, Taiwan, Republic of China (ROC, from August 15 - 19, 2011. The purpose of the Symposium was to bring space physicists together to present their recent research results and discuss some outstanding questions in, but not limited to, the solar corona, interplanetary medium, planetary magnetosphere and ionospheres. A total number of 59 papers were presented at the Symposium by scientists from 11 countries and regions.

  1. The Sun's dusty interstellar environment

    Science.gov (United States)

    Sterken, Veerle

    2016-07-01

    The Sun's dusty interstellar environment Interstellar dust from our immediate interstellar neighborhood travels through the solar system at speeds of ca. 26 km/s: the relative speed of the solar system with respect to the local interstellar cloud. On its way, its trajectories are altered by several forces like the solar radiation pressure force and Lorentz force. The latter is due to the charged dust particles that fly through the interplanetary magnetic field. These trajectories differ per particle type and size and lead to varying fluxes and directions of the flow inside of the solar system that depend on location but also on phase in the solar cycle. Hence, these fluxes and directions depend strongly on the configuration of the inner regions and outer regions of the heliosphere. Several missions have measured this dust in the solar system directly. The Ulysses dust detector data encompasses 16 years of intestellar dust fluxes and approximate directions, Stardust captured returned to Earth a few of these particles sucessfully, and finally the Cassini dust detector allowed for compositional information to be obtained from the impacts on the instrument. In this talk, we give an overview of the current status of interstellar dust research through the measurements made inside of the solar system, and we put them in perspective to the knowledge obtained from more classical astronomical means. In special, we focus on the interaction of the dust with the interplanetary magnetic field, and on what we learn about the dust (and the fields) by comparing the available dust data to computer simulations of dust trajectories. Finally, we synthesize the different methods of observation, their results, and give a preview on new research opportunities in the coming year(s).

  2. Solar system maps from antiquity to the space age

    CERN Document Server

    Kanas, Nick

    2013-01-01

    In recent years, there has been increased interest in our Solar System. This has been prompted by the launching of giant orbiting telescopes and space probes, the discovery of new planetary moons and heavenly bodies that orbit the Sun, and the demotion of Pluto as a planet. In one generation, our place in the heavens has been challenged, but this is not unusual. Throughout history, there have been a number of such world views. Initially, Earth was seen as the center of the universe and surrounded by orbiting planets and stars. Then the Sun became the center of the cosmos. Finally, there was no

  3. The faint young Sun problem

    CERN Document Server

    Feulner, Georg

    2012-01-01

    For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the `faint young Sun problem'. For the early Earth, models of stellar evolution predict a solar energy input to the climate system which is about 25% lower than today. This would result in a completely frozen world over the first two billion years in the history of our planet, if all other parameters controlling Earth's climate had been the same. Yet there is ample evidence for the presence of liquid surface water and even life in the Archean (3.8 to 2.5 billion years before present), so some effect (or effects) must have been compensating for the faint young Sun. A wide range of possible solutions have been suggested and explored during the last four decades, with most studies focusing on higher concentrations of atmospheric greenhouse gases like carbon dioxide, methane or ammonia. All of these solutions present considerable difficulties, however, so the faint young Sun prob...

  4. SunShot Vision Study: February 2012 (Book)

    Energy Technology Data Exchange (ETDEWEB)

    2012-02-01

    The objective of the SunShot Vision Study is to provide an in-depth assessment of the potential for solar technologies to meet a significant share of electricity demand in the United States during the next several decades. Specifically, it explores a future in which the price of solar technologies declines by about 75% between 2010 and 2020 - in line with the U.S. Department of Energy (DOE) SunShot Initiative's targets.

  5. The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star

    CERN Document Server

    Tu, Lin; Güdel, Manuel; Lammer, Helmut

    2015-01-01

    Aims. We aim to describe the pre-main sequence and main-sequence evolution of X-ray and extreme-ultaviolet radiation of a solar mass star based on its rotational evolution starting with a realistic range of initial rotation rates. Methods. We derive evolutionary tracks of X-ray radiation based on a rotational evolution model for solar mass stars and the rotation-activity relation. We compare these tracks to X-ray luminosity distributions of stars in clusters with different ages. Results. We find agreement between the evolutionary tracks derived from rotation and the X-ray luminosity distributions from observations. Depending on the initial rotation rate, a star might remain at the X-ray saturation level for very different time periods, approximately from 10 Myr to 300 Myr for slow and fast rotators, respectively. Conclusions. Rotational evolution with a spread of initial conditions leads to a particularly wide distribution of possible X-ray luminosities in the age range of 20 to 500 Myrs, before rotational co...

  6. The extreme ultraviolet and X-ray Sun in Time: High-energy evolutionary tracks of a solar-like star

    Science.gov (United States)

    Tu, Lin; Johnstone, Colin P.; Güdel, Manuel; Lammer, Helmut

    2015-05-01

    Aims: We aim to describe the pre-main-sequence and main-sequence evolution of X-ray and extreme-ultaviolet radiation of a solar-mass star based on its rotational evolution starting with a realistic range of initial rotation rates. Methods: We derive evolutionary tracks of X-ray radiation based on a rotational evolution model for solar-mass stars and the rotation-activity relation. We compare these tracks to X-ray luminosity distributions of stars in clusters with different ages. Results: We find agreement between the evolutionary tracks derived from rotation and the X-ray luminosity distributions from observations. Depending on the initial rotation rate, a star might remain at the X-ray saturation level for very different time periods, from ≈10 Myr to ≈300 Myr for slow and fast rotators, respectively. Conclusions: Rotational evolution with a spread of initial conditions leads to a particularly wide distribution of possible X-ray luminosities in the age range of 20-500 Myr, before rotational convergence and therefore X-ray luminosity convergence sets in. This age range is crucial for the evolution of young planetary atmospheres and may thus lead to very different planetary evolution histories.

  7. Description and primary results of Total Solar Irradiance Monitor, a solar-pointing instrument on an Earth observing satellite

    Science.gov (United States)

    Wang, Hongrui; Fang, Wei; Li, Huiduan

    2015-04-01

    Solar driving mechanism for Earth climate has been a controversial problem for centuries. Long-time data of solar activity is required by the investigations of the solar driving mechanism, such as Total Solar Irradiance (TSI) record. Three Total Solar Irradiance Monitors (TSIM) have been developed by Changchun Institute of Optics, Fine Mechanics and Physics for China Meteorological Administration to maintain continuities of TSI data series which lasted for nearly 4 decades.The newest TSIM has recorded TSI daily with accurate solar pointing on the FY-3C meteorological satellite since Oct 2013. TSIM/FY-3C has a pointing system for automatic solar tracking, onboard the satellite designed mainly for Earth observing. Most payloads of FY-3C are developed for observation of land, ocean and atmosphere. Consequently, the FY-3C satellite is a nadir-pointing spacecraft with its z axis to be pointed at the center of the Earth. Previous TSIMs onboard the FY-3A and FY-3B satellites had no pointing system, solar observations were only performed when the sun swept through field-of-view of the instruments. And TSI measurements are influenced inevitably by the solar pointing errors. Corrections of the solar pointing errors were complex. The problem is now removed by TSIM/FY-3C.TSIM/FY-3C follows the sun accurately by itself using its pointing system based on scheme of visual servo control. The pointing system is consisted of a radiometer package, two motors for solar tracking, a sun sensor and etc. TSIM/FY-3C has made daily observations of TSI for more than one year, with nearly zero solar pointing errors. Short time-scale variations in TSI detected by TSIM/FY-3C are nearly the same with VIRGO/SOHO and TIM/SORCE.Instrument details, primary results of solar pointing control, solar observations and etc will be given in the presentation.

  8. The radiation belt of the Sun

    CERN Document Server

    Gruzinov, Andrei

    2013-01-01

    For a given solar magnetic field, the near-Sun (phase-space) density of cosmic ray electrons and positrons of energy above about 10GeV can be calculated from first principles, without any assumptions about the cosmic ray diffusion. This is because the sunlight Compton drag must be more important than diffusion. If the solar magnetic field has an appreciable dipole component, the electron/positron density should have a belt-like dent, perhaps extending to several solar radii. The belt structure appears because the quasi-bound orbits are depopulated by the sunlight Compton drag.

  9. Selective factors in sun-weather research

    Science.gov (United States)

    Taylor, H. A., Jr.

    1986-01-01

    Research on the correlations between solar wind/IMF disturbances and subsequent winter troposphere vorticity changes (denoted SV) are reviewed to investigate sun-weather relationships. Uncertainties in the research attempting to link short-term solar variations and associated changes in the lower atmosphere are discussed, and it is noted that such analyses have generally not addressed either the choice of parameters or the selective factors involved in the physical relationships existing between parameters. It is suggested that the identification of a viable mechanism scenario would require a detailed multiparameter selective factor analysis, extending to the investigation of the atmospheric data as well as the solar wind/IMF parameters.

  10. Investigation of possible sun-weather relationships

    Energy Technology Data Exchange (ETDEWEB)

    Businger, S

    1978-01-01

    Statistical correlations between anomalous solar activity (as denoted by large solar flares, active plages, and interplanetary magnetic sector boundaries) and the circulation of the troposphere are reviewed. Two indices (measuring atmospheric vorticity and mean zonal geostrophic flow in the northern hemisphere) are analyzed in an effort to reveal possible sun-weather relationships. The result of this analysis provides no additional statistical evidence for a connection between solar activity and the weather. Finally, physical mechanisms that have been suggested to explain the claimed correlations are discussed.

  11. On the Path to SunShot - Emerging Issues and Challenges with Integrating High Levels of Solar into the Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    Palminitier, Bryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Broderick, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mather, Barry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Coddington, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baker, Kyri [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ding, Fei [National Renewable Energy Lab. (NREL), Golden, CO (United States); Reno, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lave, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bharatkumar, Ashwini [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2016-05-01

    Wide use of advanced inverters could double the electricity-distribution system’s hosting capacity for distributed PV at low costs—from about 170 GW to 350 GW (see Palmintier et al. 2016). At the distribution system level, increased variable generation due to high penetrations of distributed PV (typically rooftop and smaller ground-mounted systems) could challenge the management of distribution voltage, potentially increase wear and tear on electromechanical utility equipment, and complicate the configuration of circuit-breakers and other protection systems—all of which could increase costs, limit further PV deployment, or both. However, improved analysis of distribution system hosting capacity—the amount of distributed PV that can be interconnected without changing the existing infrastructure or prematurely wearing out equipment—has overturned previous rule-of-thumb assumptions such as the idea that distributed PV penetrations higher than 15% require detailed impact studies. For example, new analysis suggests that the hosting capacity for distributed PV could rise from approximately 170 GW using traditional inverters to about 350 GW with the use of advanced inverters for voltage management, and it could be even higher using accessible and low-cost strategies such as careful siting of PV systems within a distribution feeder and additional minor changes in distribution operations. Also critical to facilitating distributed PV deployment is the improvement of interconnection processes, associated standards and codes, and compensation mechanisms so they embrace PV’s contributions to system-wide operations. Ultimately SunShot-level PV deployment will require unprecedented coordination of the historically separate distribution and transmission systems along with incorporation of energy storage and “virtual storage,” which exploits improved management of electric vehicle charging, building energy systems, and other large loads. Additional analysis and

  12. Radio sounding of the solar corona during 1995 solar conjunction of the Ulysses spacecraft

    Science.gov (United States)

    Bird, M. K.; Paetzold, M.; Karl, J.; Edenhofer, P.; Asmar, S. W.

    1995-01-01

    The Ulysses spacecraft will pass through superior solar conjunction on March 5 1995, a few days before its perihelion and passage through the ecliptic plane. Dual-frequency S/X-band ranging and Doppler observations will be conducted in support of the Ulysses Solar Corona Experiment (SCE) during a three-week interval centered on the conjunction. The occultation geometry is unique in the annals of interplanetary exploration. As viewed from Earth, the spacecraft will appear to cut diagonally through the southwest quadrant of the solar corona from the South Pole to the equator. The minimum proximate distance to the Sun of the radio ray path will be 21.6 solar radius. The entire latitude scan from pole to equator occurs for a limited range of solar offset distances (is less than 30 solar radius thus facilitating the separation of latitudinal from radial variations in the coronal density and associated parameters of interest.

  13. Observing the sun a pocket field guide

    CERN Document Server

    Jenkins, Jamey L

    2013-01-01

    A comprehensive solar observing guide for use at the telescope by amateur astronomers at all three levels: beginning, intermediate, and advanced. Users will find invaluable information for identifying features through photos, charts, diagrams in a logical, orderly fashion and then interpreting the observations. Because the Sun is a dynamic celestial body in constant flux, astronomers rarely know for certain what awaits them at the eyepiece. All features of the Sun are transient and sometimes rather fleeting. Given the number of features and the complex life cycles of some solar features, it can be a challenging hobby, and this guide provides all of the guidance necessary to inform observers about the sights and events unfolding before their eyes on the most active and powerful member of our Solar System.

  14. The DKIST Data Center: Meeting the Data Challenges for Next-Generation, Ground-Based Solar Physics

    Science.gov (United States)

    Davey, A. R.; Reardon, K.; Berukoff, S. J.; Hays, T.; Spiess, D.; Watson, F. T.; Wiant, S.

    2016-12-01

    The Daniel K. Inouye Solar Telescope (DKIST) is under construction on the summit of Haleakalā in Maui, and scheduled to start science operations in 2020. The DKIST design includes a four-meter primary mirror coupled to an adaptive optics system, and a flexible instrumentation suite capable of delivering high-resolution optical and infrared observations of the solar chromosphere, photosphere, and corona. Through investigator-driven science proposals, the facility will generate an average of 8 TB of data daily, comprised of millions of images and hundreds of millions of metadata elements. The DKIST Data Center is responsible for the long-term curation and calibration of data received from the DKIST, and for distributing it to the user community for scientific use. Two key elements necessary to meet the inherent big data challenge are the development of flexible public/private cloud computing and coupled relational and non-relational data storage mechanisms. We discuss how this infrastructure is being designed to meet the significant expectation of automatic and manual calibration of ground-based solar physics data, and the maximization the data's utility through efficient, long-term data management practices implemented with prudent process definition and technology exploitation.

  15. On the Observations of the Sun in Polynesia

    CERN Document Server

    Rjabchikov, Sergei

    2014-01-01

    The role of the Polynesian sun god Tagaloa has been studied. The Polynesian characters Maui-tikitiki, Tane and Tiki were related to the sun as well. The solar data of Easter Island are essential indeed. The rongorongo text on the Santiago staff about the solar eclipse of December 20, 1805 A.D. has been decoded. The Mataveri calendar was probably incised on a rock in 1775 A.D. So, a central event during the bird-man festval was the day of vernal equinox. The priests-astronomers watched not only the sun and the moon, but also some stars of the zodiacal constellations and other bright stars.

  16. The Maunder minimum and the variable sun-earth connection

    CERN Document Server

    Wei Hock Soon, Willie

    2003-01-01

    This book takes an excursion through solar science, science history, and geoclimate with a husband and wife team who revealed some of our sun's most stubborn secrets. E Walter and Annie S D Maunder's work helped in understanding our sun's chemical, electromagnetic and plasma properties. They knew the sun's sunspot migration patterns and its variable, climate-affecting, inactive and active states in short and long time frames. An inactive solar period starting in the mid-seventeenth century lasted approximately seventy years, one that E Walter Maunder worked hard to make us understand: the Maun

  17. Nearest star the surprising science of our sun

    CERN Document Server

    Golub, Leon

    2014-01-01

    How did the Sun evolve, and what will it become? What is the origin of its light and heat? How does solar activity affect the atmospheric conditions that make life on Earth possible? These are the questions at the heart of solar physics, and at the core of this book. The Sun is the only star near enough to study in sufficient detail to provide rigorous tests of our theories and help us understand the more distant and exotic objects throughout the cosmos. Having observed the Sun using both ground-based and spaceborne instruments, the authors bring their extensive personal experience to this sto

  18. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  19. Orientation in birds. The sun compass.

    Science.gov (United States)

    Schmidt-Koenig, K; Ganzhorn, J U; Ranvaud, R

    1991-01-01

    The sun compass was discovered by G. Kramer in caged birds showing migratory restlessness. Subsequent experiments with caged birds employing directional training and clock shifts, carried out by Hoffman and Schmidt-Koenig, showed that the sun azimuth is used, and the sun altitude ignored. In the laboratory, McDonald found the accuracy to be +/- 3 degrees(-)+/- 5 degrees. According to Hoffmann and Schmidt-Koenig, caged birds trained at medium northern latitudes were able to allow for the sun's apparent movement north of the arctic circle, but not in equatorial and trans-equatorial latitudes. In homing experiments, and employing clock shifts, Schmidt-Koenig demonstrated that the sun compass is used by homing pigeons during initial orientation. This finding is the principal evidence for the existence of a map-and-compass navigational system. Pigeons living in equatorial latitudes utilize the sun compass even under the extreme solar conditions of equinox, achieving angular resolution of about 3 degrees in homing experiments. According to preliminary analyses, the homing pigeons' ephemerides are retarded by several weeks (Ranvaud, Schmidt-Koenig, Ganzhorn et al.).

  20. Commentary Relative to the Emission Spectrum of the Solar Atmosphere: Further Evidence for a Distinct Solar Surface

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2013-07-01

    Full Text Available The chromosphere and corona of the Sun represent tenuous regions which are characterized by numerous optically thin emission lines in the ultraviolet and X-ray bands. When observed from the center of the solar disk outward, these emission lines experience modest brightening as the limb is approached. The intensity of many ultraviolet and X-ray emission lines nearly doubles when observation is extended just beyond the edge of the disk. These findings indicate that the solar body is opaque in this frequency range and that an approximately two fold greater region of the solar atmosphere is being sampled outside the limb. These observations provide strong support for the presence of a distinct solar surface. Therefore, the behavior of the emission lines in this frequency range constitutes the twenty fifth line of evidence that the Sun is comprised of condensed matter