WorldWideScience

Sample records for maximum solar activity

  1. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

  2. Simultaneous Solar Maximum Mission (SMM) and Very Large Array (VLA) observations of solar active regions

    Science.gov (United States)

    Willson, Robert F.

    1991-01-01

    Very Large Array observations at 20 cm wavelength can detect the hot coronal plasma previously observed at soft x ray wavelengths. Thermal cyclotron line emission was detected at the apex of coronal loops where the magnetic field strength is relatively constant. Detailed comparison of simultaneous Solar Maximum Mission (SMM) Satellite and VLA data indicate that physical parameters such as electron temperature, electron density, and magnetic field strength can be obtained, but that some coronal loops remain invisible in either spectral domain. The unprecedent spatial resolution of the VLA at 20 cm wavelength showed that the precursor, impulsive, and post-flare components of solar bursts originate in nearby, but separate loops or systems of loops.. In some cases preburst heating and magnetic changes are observed from loops tens of minutes prior to the impulsive phase. Comparisons with soft x ray images and spectra and with hard x ray data specify the magnetic field strength and emission mechanism of flaring coronal loops. At the longer 91 cm wavelength, the VLA detected extensive emission interpreted as a hot 10(exp 5) K interface between cool, dense H alpha filaments and the surrounding hotter, rarefield corona. Observations at 91 cm also provide evidence for time-correlated bursts in active regions on opposite sides of the solar equator; they are attributed to flare triggering by relativistic particles that move along large-scale, otherwise-invisible, magnetic conduits that link active regions in opposite hemispheres of the Sun.

  3. Proton Fluxes Measured by the PAMELA Experiment from the Minimum to the Maximum Solar Activity for Solar Cycle 24

    Science.gov (United States)

    Martucci, M.; Munini, R.; Boezio, M.; Di Felice, V.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; De Santis, C.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Marcelli, L.; Marcelli, N.; Mayorov, A. G.; Menn, W.; Mergè, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Osteria, G.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Potgieter, M. S.; Raath, J. L.

    2018-02-01

    Precise measurements of the time-dependent intensity of the low-energy (solar activity periods, i.e., from minimum to maximum, are needed to achieve comprehensive understanding of such physical phenomena. The minimum phase between solar cycles 23 and 24 was peculiarly long, extending up to the beginning of 2010 and followed by the maximum phase, reached during early 2014. In this Letter, we present proton differential spectra measured from 2010 January to 2014 February by the PAMELA experiment. For the first time the GCR proton intensity was studied over a wide energy range (0.08–50 GeV) by a single apparatus from a minimum to a maximum period of solar activity. The large statistics allowed the time variation to be investigated on a nearly monthly basis. Data were compared and interpreted in the context of a state-of-the-art three-dimensional model describing the GCRs propagation through the heliosphere.

  4. Simultaneous Solar Maximum Mission (SMM) and very large array observations of solar active regions

    Science.gov (United States)

    Lang, K. R.

    1986-01-01

    The research deals mainly with Very Large Array and Solar Maximum Mission observations of the ubiquitous coronal loops that dominate the structure of the low corona. As illustrated, the observations of thermal cyclotron lines at microwave wavelengths provide a powerful new method of accurately specifying the coronal magnetic field strength. Processes are delineated that trigger solar eruptions from coronal loops, including preburst heating and the magnetic interaction of coronal loops. Evidence for coherent burst mechanisms is provided for both the Sun and nearby stars, while other observations suggest the presence of currents that may amplify the coronal magnetic field to unexpectedly high levels. The existence is reported of a new class of compact, variable moving sources in regions of apparently weak photospheric field.

  5. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

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

  6. The ancient Egyptian civilization: maximum and minimum in coincidence with solar activity

    Science.gov (United States)

    Shaltout, M.

    It is proved from the last 22 years observations of the total solar irradiance (TSI) from space by artificial satellites, that TSI shows negative correlation with the solar activity (sunspots, flares, and 10.7cm Radio emissions) from day to day, but shows positive correlations with the same activity from year to year (on the base of the annual average for each of them). Also, the solar constant, which estimated fromth ground stations for beam solar radiations observations during the 20 century indicate coincidence with the phases of the 11- year cycles. It is known from sunspot observations (250 years) , and from C14 analysis, that there are another long-term cycles for the solar activity larger than 11-year cycle. The variability of the total solar irradiance affecting on the climate, and the Nile flooding, where there is a periodicities in the Nile flooding similar to that of solar activity, from the analysis of about 1300 years of the Nile level observations atth Cairo. The secular variations of the Nile levels, regularly measured from the 7 toth 15 century A.D., clearly correlate with the solar variations, which suggests evidence for solar influence on the climatic changes in the East African tropics The civilization of the ancient Egyptian was highly correlated with the Nile flooding , where the river Nile was and still yet, the source of the life in the Valley and Delta inside high dry desert area. The study depends on long -time historical data for Carbon 14 (more than five thousands years), and chronical scanning for all the elements of the ancient Egyptian civilization starting from the firs t dynasty to the twenty six dynasty. The result shows coincidence between the ancient Egyptian civilization and solar activity. For example, the period of pyramids building, which is one of the Brilliant periods, is corresponding to maximum solar activity, where the periods of occupation of Egypt by Foreign Peoples corresponding to minimum solar activity. The decline

  7. MAXIMUM CORONAL MASS EJECTION SPEED AS AN INDICATOR OF SOLAR AND GEOMAGNETIC ACTIVITIES

    International Nuclear Information System (INIS)

    Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Gopalswamy, N.; Ozguc, A.; Rozelot, J. P.

    2011-01-01

    We investigate the relationship between the monthly averaged maximal speeds of coronal mass ejections (CMEs), international sunspot number (ISSN), and the geomagnetic Dst and Ap indices covering the 1996-2008 time interval (solar cycle 23). Our new findings are as follows. (1) There is a noteworthy relationship between monthly averaged maximum CME speeds and sunspot numbers, Ap and Dst indices. Various peculiarities in the monthly Dst index are correlated better with the fine structures in the CME speed profile than that in the ISSN data. (2) Unlike the sunspot numbers, the CME speed index does not exhibit a double peak maximum. Instead, the CME speed profile peaks during the declining phase of solar cycle 23. Similar to the Ap index, both CME speed and the Dst indices lag behind the sunspot numbers by several months. (3) The CME number shows a double peak similar to that seen in the sunspot numbers. The CME occurrence rate remained very high even near the minimum of the solar cycle 23, when both the sunspot number and the CME average maximum speed were reaching their minimum values. (4) A well-defined peak of the Ap index between 2002 May and 2004 August was co-temporal with the excess of the mid-latitude coronal holes during solar cycle 23. The above findings suggest that the CME speed index may be a useful indicator of both solar and geomagnetic activities. It may have advantages over the sunspot numbers, because it better reflects the intensity of Earth-directed solar eruptions.

  8. Electron density variations in the F2 layer maximum during solar activity cycle

    International Nuclear Information System (INIS)

    Besprozvannaya, A.S.; Kozina, P.E.; AN Kazakhskoj SSR, Alma-Ata. Sektor Ionosfery)

    1988-01-01

    R value, characterizing for F2 relation of hourly median values in solar activity minimum and maximum, is calculated by average monthly values of F2 layer critical frequencies for June, October and December 1958 and 1964. R latitudinal-temporal distributions are plotted for different seasons according to the data from the north hemisphere west and east stations, placed within the Φ'=35-70deg latitudes interval. The following peculiarities of F2 lyer ionization relation with solar activity are pointed out. There are day-time hours, they are - winter one characterized by the gain rate increase with the widths increase, and summer one, realizing the opposite regularity. In night-time hours R value is characterized by the abnormally low values (∼ 1.2) at the latitudes to the south of the ionospheric through and to the pole from it. For all three seasons during 24 hours the periods with ionization gain maximal rate, which occur at nights in summer time and in the hours after the sunset - in winter and equinoctial months, are observed. The quantitative explanation of the peculiarities detected concerning the to-day concepts on F2 layer formation mechanisms is given

  9. The Maximum Free Magnetic Energy Allowed in a Solar Active Region

    Science.gov (United States)

    Moore, Ronald L.; Falconer, David A.

    2009-01-01

    Two whole-active-region magnetic quantities that can be measured from a line-of-sight magnetogram are (sup L) WL(sub SG), a gauge of the total free energy in an active region's magnetic field, and sup L(sub theta), a measure of the active region's total magnetic flux. From these two quantities measured from 1865 SOHO/MDI magnetograms that tracked 44 sunspot active regions across the 0.5 R(sub Sun) central disk, together with each active region's observed production of CMEs, X flares, and M flares, Falconer et al (2009, ApJ, submitted) found that (1) active regions have a maximum attainable free magnetic energy that increases with the magnetic size (sup L) (sub theta) of the active region, (2) in (Log (sup L)WL(sub SG), Log(sup L) theta) space, CME/flare-productive active regions are concentrated in a straight-line main sequence along which the free magnetic energy is near its upper limit, and (3) X and M flares are restricted to large active regions. Here, from (a) these results, (b) the observation that even the greatest X flares produce at most only subtle changes in active region magnetograms, and (c) measurements from MSFC vector magnetograms and from MDI line-of-sight magnetograms showing that practically all sunspot active regions have nearly the same area-averaged magnetic field strength: =- theta/A approximately equal to 300 G, where theta is the active region's total photospheric flux of field stronger than 100 G and A is the area of that flux, we infer that (1) the maximum allowed ratio of an active region's free magnetic energy to its potential-field energy is 1, and (2) any one CME/flare eruption releases no more than a small fraction (less than 10%) of the active region's free magnetic energy. This work was funded by NASA's Heliophysics Division and NSF's Division of Atmospheric Sciences.

  10. Simultaneous Solar Maximum Mission and Very Large Array (VLA) observations of solar active regions. Semiannual Progress Report, 1 February 1985-30 January 1986

    International Nuclear Information System (INIS)

    Lang, K.R.

    1985-08-01

    Simultaneous observations of solar active regions with the Solar Maximum Mission (SMM) Satellite and the Very Large Array (VLA) have been obtained and analyzed. Combined results enhance the scientific return for beyond that expeted from using either SMM or VLA alone. A total of two weeks of simultaneous SMM/VLA data were obtained. The multiple wavelength VLA observations were used to determine the temperature and magnetic structure at different heights within coronal loops. These data are compared with simultaneous SMM observations. Several papers on the subject are in progress. They include VLA observations of compact, transient sources in the transition region; simultaneous SMM/VLA observations of the coronal loops in one active region and the evolution of another one; and sampling of the coronal plasma using thermal cyclotron lines (magnetic field - VLA) and soft X ray spectral lines (electron density and electron temperaure-SMM)

  11. Maximum Power from a Solar Panel

    Directory of Open Access Journals (Sweden)

    Michael Miller

    2010-01-01

    Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.

  12. Fractal Dimension and Maximum Sunspot Number in Solar Cycle

    Directory of Open Access Journals (Sweden)

    R.-S. Kim

    2006-09-01

    Full Text Available The fractal dimension is a quantitative parameter describing the characteristics of irregular time series. In this study, we use this parameter to analyze the irregular aspects of solar activity and to predict the maximum sunspot number in the following solar cycle by examining time series of the sunspot number. For this, we considered the daily sunspot number since 1850 from SIDC (Solar Influences Data analysis Center and then estimated cycle variation of the fractal dimension by using Higuchi's method. We examined the relationship between this fractal dimension and the maximum monthly sunspot number in each solar cycle. As a result, we found that there is a strong inverse relationship between the fractal dimension and the maximum monthly sunspot number. By using this relation we predicted the maximum sunspot number in the solar cycle from the fractal dimension of the sunspot numbers during the solar activity increasing phase. The successful prediction is proven by a good correlation (r=0.89 between the observed and predicted maximum sunspot numbers in the solar cycles.

  13. Solar maximum mission panel jettison analysis remote manipulator system

    Science.gov (United States)

    Bauer, R. B.

    1980-01-01

    A study is presented of the development of the Remote Manipulator System (RMS) configurations for jettison of the solar panels on the Solar Maximum Mission/Multimission Satellite. A valid RMS maneuver between jettison configurations was developed. Arm and longeron loads and effector excursions due to the solar panel jettison were determined to see if they were within acceptable limits. These loads and end effector excursions were analyzed under two RMS modes, servos active in position hold submode, and in the brakes on mode.

  14. Strong Solar Control of Infrared Aurora on Jupiter: Correlation Since the Last Solar Maximum

    Science.gov (United States)

    Kostiuk, T.; Livengood, T. A.; Hewagama, T.

    2009-01-01

    Polar aurorae in Jupiter's atmosphere radiate throughout the electromagnetic spectrum from X ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based spectroscopic measurements of Jupiter's northern mid-IR aurora, acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane emission brightness and solar 10.7 cm radio flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high solar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the Europa Jupiter System Mission. Results of observations at the Infrared Telescope Facility (IRTF) operated by the University of Hawaii under Cooperative Agreement no. NCC5-538 with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. This work was supported by the NASA Planetary Astronomy Program.

  15. THE RISE AND FALL OF OPEN SOLAR FLUX DURING THE CURRENT GRAND SOLAR MAXIMUM

    International Nuclear Information System (INIS)

    Lockwood, M.; Rouillard, A. P.; Finch, I. D.

    2009-01-01

    We use geomagnetic activity data to study the rise and fall over the past century of the solar wind flow speed V SW , the interplanetary magnetic field strength B, and the open solar flux F S . Our estimates include allowance for the kinematic effect of longitudinal structure in the solar wind flow speed. As well as solar cycle variations, all three parameters show a long-term rise during the first half of the 20th century followed by peaks around 1955 and 1986 and then a recent decline. Cosmogenic isotope data reveal that this constitutes a grand maximum of solar activity which began in 1920, using the definition that such grand maxima are when 25-year averages of the heliospheric modulation potential exceeds 600 MV. Extrapolating the linear declines seen in all three parameters since 1985, yields predictions that the grand maximum will end in the years 2013, 2014, or 2027 using V SW , F S , or B, respectively. These estimates are consistent with predictions based on the probability distribution of the durations of past grand solar maxima seen in cosmogenic isotope data. The data contradict any suggestions of a floor to the open solar flux: we show that the solar minimum open solar flux, kinematically corrected to allow for the excess flux effect, has halved over the past two solar cycles.

  16. Solar maximum ultraviolet spectrometer and polarimeter

    Science.gov (United States)

    Tandberg-Hanssen, E.; Woodgate, B. E.; Brandt, J. C.; Chapman, R. D.; Hyder, C. L.; Michalitsianos, A. G.; Shine, R. A.; Athay, R. G.; Beckers, J. M.; Bruner, E. C.

    1979-01-01

    The objectives of the UVSP experiment are to study solar ultraviolet radiations, particularly from flares and active regions, and to measure constituents in the terrestrial atmosphere by the extinction of sunlight at satellite dawn and dusk. The instrument is designed to observe the Sun at a variety of spectral and spatial resolutions in the range from 1150 to 3600 A. A Gregorian telescope with effective focal length of 1.8 m is used to feed a 1 m Ebert-Fastie spectrometer. A polarimeter containing rotatable magnesium fluoride waveplates is included behind the spectrometer entrance slit and will allow all four Stokes parameters to be determined. Velocities on the Sun can also be measured. The instrument is controlled by a computer which can interact with the data stream to modify the observing program. The observing modes, including rasters, spectral scans, velocity measurements, and polarimetry, are also described along with plans for mission operations, data handling, and analysis of the observations.

  17. Weakest solar wind of the space age and the current 'MINI' solar maximum

    International Nuclear Information System (INIS)

    McComas, D. J.; Angold, N.; Elliott, H. A.; Livadiotis, G.; Schwadron, N. A.; Smith, C. W.; Skoug, R. M.

    2013-01-01

    The last solar minimum, which extended into 2009, was especially deep and prolonged. Since then, sunspot activity has gone through a very small peak while the heliospheric current sheet achieved large tilt angles similar to prior solar maxima. The solar wind fluid properties and interplanetary magnetic field (IMF) have declined through the prolonged solar minimum and continued to be low through the current mini solar maximum. Compared to values typically observed from the mid-1970s through the mid-1990s, the following proton parameters are lower on average from 2009 through day 79 of 2013: solar wind speed and beta (∼11%), temperature (∼40%), thermal pressure (∼55%), mass flux (∼34%), momentum flux or dynamic pressure (∼41%), energy flux (∼48%), IMF magnitude (∼31%), and radial component of the IMF (∼38%). These results have important implications for the solar wind's interaction with planetary magnetospheres and the heliosphere's interaction with the local interstellar medium, with the proton dynamic pressure remaining near the lowest values observed in the space age: ∼1.4 nPa, compared to ∼2.4 nPa typically observed from the mid-1970s through the mid-1990s. The combination of lower magnetic flux emergence from the Sun (carried out in the solar wind as the IMF) and associated low power in the solar wind points to the causal relationship between them. Our results indicate that the low solar wind output is driven by an internal trend in the Sun that is longer than the ∼11 yr solar cycle, and they suggest that this current weak solar maximum is driven by the same trend.

  18. Solar Maximum Mission Experiment - Ultraviolet Spectroscopy and Polarimetry on the Solar Maximum Mission

    Science.gov (United States)

    Tandberg-Hanssen, E.; Cheng, C. C.; Woodgate, B. E.; Brandt, J. C.; Chapman, R. D.; Athay, R. G.; Beckers, J. M.; Bruner, E. C.; Gurman, J. B.; Hyder, C. L.

    1981-01-01

    The Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission spacecraft is described. It is pointed out that the instrument, which operates in the wavelength range 1150-3600 A, has a spatial resolution of 2-3 arcsec and a spectral resolution of 0.02 A FWHM in second order. A Gregorian telescope, with a focal length of 1.8 m, feeds a 1 m Ebert-Fastie spectrometer. A polarimeter comprising rotating Mg F2 waveplates can be inserted behind the spectrometer entrance slit; it permits all four Stokes parameters to be determined. Among the observing modes are rasters, spectral scans, velocity measurements, and polarimetry. Examples of initial observations made since launch are presented.

  19. Preliminary observations and results obtained with the ultraviolet spectrometer and polarimeter. [for Solar Maximum Mission

    Science.gov (United States)

    Tandberg-Hassen, E.; Cheng, C. C.; Athay, R. G.; Beckers, J. M.; Brandt, J. C.; Chapman, R. D.; Bruner, E. C.; Henze, W.; Hyder, C. L.; Gurman, J. B.

    1981-01-01

    New observation with the Ultraviolet Spectrometer and Polarimeter (UVSP) of a number of manifestations of solar activity obtained during the first three months of Solar Maximum Mission operations are presented. Attention is given to polarimetry in sunspots, oscillations above sunspots, density diagnostics of transition-zone plasmas in active regions, and the eruptive prominence - coronal transient link.

  20. Solar irridiance variations and solar activity

    International Nuclear Information System (INIS)

    Willson, R.C.

    1982-01-01

    A mean value for the 1 AU total solar irradiance of 1368.2 W/m 2 and a downward trend of 0.05% per year were derived from measurements by the Active Cavity Radiometer Irradiance Monitor (ACRIM) experiment on the Solar Maximum Mission during 1980. Distinct temporary solar irradiance decreases associated with solar activity maxima were observed with a series of nine dips from April to October recurring at fairly regular intervals averaging 24 days. The decreases correlate inversely with sunspot area, 2800-MHz flux, and Zurich sunspot number. Dominant periods common to the irradiance and sunspot area power spectra link the irradiance decreases to sunspot flux deficit in solar active regions. Evidence of significant total irradiance modulation by facular flux excess is cited. A persistent radiative cycle of active regions consistent with the ACRIM irradiance results and the morphology of solar active regions was found. The pattern of regularly recurrent active region maxima between April and October suggests an asymmetry in solar activity generation during this period

  1. Max '91: Flare research at the next solar maximum

    Science.gov (United States)

    Dennis, Brian; Canfield, Richard; Bruner, Marilyn; Emslie, Gordon; Hildner, Ernest; Hudson, Hugh; Hurford, Gordon; Lin, Robert; Novick, Robert; Tarbell, Ted

    1988-01-01

    To address the central scientific questions surrounding solar flares, coordinated observations of electromagnetic radiation and energetic particles must be made from spacecraft, balloons, rockets, and ground-based observatories. A program to enhance capabilities in these areas in preparation for the next solar maximum in 1991 is recommended. The major scientific issues are described, and required observations and coordination of observations and analyses are detailed. A program plan and conceptual budgets are provided.

  2. Max '91: flare research at the next solar maximum

    International Nuclear Information System (INIS)

    Dennis, B.; Canfield, R.; Bruner, M.

    1988-01-01

    To address the central scientific questions surrounding solar flares, coordinated observations of electromagnetic radiation and energetic particles must be made from spacecraft, balloons, rockets, and ground-based observatories. A program to enhance capabilities in these areas in preparation for the next solar maximum in 1991 is recommended. The major scientific issues are described, and required observations and coordination of observations and analyses are detailed. A program plan and conceptual budgets are provided

  3. Solar coronal non-thermal processes (Solar Maximum Mission). Final report

    International Nuclear Information System (INIS)

    Hudson, H.S.

    1983-02-01

    The Solar Maximum Mission was used to study solar coronal phenomena in hard X-radiation, since its instrument complement included the first solar hard X-ray telescope. Phenomena related to those discovered from OSO-5 and OSO-7 observations were emphasized

  4. Observations of Halley's Comet by the Solar Maximum Mission (SMM)

    Science.gov (United States)

    Niedner, M. B.

    1986-01-01

    Solar Maximum Mission coronagraph/polarimeter observations of large scale phenomena in Halley's Comet are discussed. Observations of the hydrogen coma with the UV spectrometer are considered. It is concluded that coronograph/polarimeter observations of the disconnection event, in which the entire plasma tail uproots itself from the head of the comet, is convected away in the solar wind at speeds in the 50 to 100 km/sec range (relative to the head), and is replaced by a plasma tail constructed from folding ion-tail rays, are the most interesting.

  5. Maximum-power-point tracking control of solar heating system

    KAUST Repository

    Huang, Bin-Juine

    2012-11-01

    The present study developed a maximum-power point tracking control (MPPT) technology for solar heating system to minimize the pumping power consumption at an optimal heat collection. The net solar energy gain Q net (=Q s-W p/η e) was experimentally found to be the cost function for MPPT with maximum point. The feedback tracking control system was developed to track the optimal Q net (denoted Q max). A tracking filter which was derived from the thermal analytical model of the solar heating system was used to determine the instantaneous tracking target Q max(t). The system transfer-function model of solar heating system was also derived experimentally using a step response test and used in the design of tracking feedback control system. The PI controller was designed for a tracking target Q max(t) with a quadratic time function. The MPPT control system was implemented using a microprocessor-based controller and the test results show good tracking performance with small tracking errors. It is seen that the average mass flow rate for the specific test periods in five different days is between 18.1 and 22.9kg/min with average pumping power between 77 and 140W, which is greatly reduced as compared to the standard flow rate at 31kg/min and pumping power 450W which is based on the flow rate 0.02kg/sm 2 defined in the ANSI/ASHRAE 93-1986 Standard and the total collector area 25.9m 2. The average net solar heat collected Q net is between 8.62 and 14.1kW depending on weather condition. The MPPT control of solar heating system has been verified to be able to minimize the pumping energy consumption with optimal solar heat collection. © 2012 Elsevier Ltd.

  6. The radial distribution of cosmic rays in the heliosphere at solar maximum

    Science.gov (United States)

    McDonald, F. B.; Fujii, Z.; Heikkila, B.; Lal, N.

    2003-08-01

    To obtain a more detailed profile of the radial distribution of galactic (GCRs) and anomalous (ACRs) cosmic rays, a unique time in the 11-year solar activity cycle has been selected - that of solar maximum. At this time of minimum cosmic ray intensity a simple, straight-forward normalization technique has been found that allows the cosmic ray data from IMP 8, Pioneer 10 (P-10) and Voyagers 1 and 2 (V1, V2) to be combined for the solar maxima of cycles 21, 22 and 23. This combined distribution reveals a functional form of the radial gradient that varies as G 0/r with G 0 being constant and relatively small in the inner heliosphere. After a transition region between ˜10 and 20 AU, G 0 increases to a much larger value that remains constant between ˜25 and 82 AU. This implies that at solar maximum the changes that produce the 11-year modulation cycle are mainly occurring in the outer heliosphere between ˜15 AU and the termination shock. These observations are not inconsistent with the concept that Global Merged Interaction. regions (GMIRs) are the principal agent of modulation between solar minimum and solar maximum. There does not appear to be a significant change in the amount of heliosheath modulation occurring between the 1997 solar minimum and the cycle 23 solar maximum.

  7. Nanocrystalline dye-sensitized solar cells having maximum performance

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, M.; Bakker, N.J.; Smit, H.J.P. [ECN Solar Energy, Petten (Netherlands); Liska, P.; Thampi, K.R.; Wang, P.; Zakeeruddin, S.M.; Graetzel, M. [LPI-ISIC, Ecole Polytechnique Federale de Lausanne EPFL, Station 6, CH-1015 Lausanne (Switzerland); Hinsch, A. [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr.2, D-79110 Freiburg (Germany); Hore, S.; Wuerfel, U.; Sastrawan, R. [Freiburg Materials Research Centre FMF, Stefan-Meier Str. 21, 79104 Freiburg (Germany); Durrant, J.R.; Palomares, E. [Centre for Electronic Materials and Devices, Department of Chemistry, Imperial College London, Exhibition road SW7 2AY (United Kingdom); Pettersson, H.; Gruszecki, T. [IVF Industrial Research and Development Corporation, Argongatan 30, SE-431 53 Moelndal (Sweden); Walter, J.; Skupien, K. [Cracow University of Technology CUTECH, Jana Pawla II 37, 31-864 Cracow (Poland); Tulloch, G.E. [Greatcell Solar SA GSA, Ave Henry-Warnery 4, 1006 Lausanne (Switzerland)

    2007-01-15

    This paper presents an overview of the research carried out by a European consortium with the aim to develop and test new and improved ways to realise dye-sensitized solar cells (DSC) with enhanced efficiencies and stabilities. Several new areas have been explored in the field of new concepts and materials, fabrication protocols for TiO2 and scatterlayers, metal oxide blocking layers, strategies for co-sensitization and low temperature processes of platinum deposition. Fundamental understanding of the working principles has been gained by means of electrical and optical modelling and advanced characterization techniques. Cost analyses have been made to demonstrate the potential of DSC as a low cost thin film PV technology. The combined efforts have led to maximum non-certified power conversion efficiencies under full sunlight of 11% for areas <0c2 cm{sup 2} and 10c1% for a cell with an active area of 1c3 cm{sup 2}. Lifetime studies revealed negligible device degradation after 1000 hrs of accelerated tests under thermal stress at 80C in the dark and visible light soaking at 60C. An outlook summarizing future directions in the research and large-scale production of DSC is presented.

  8. Gamma ray detector for solar maximum mission (SMM) of NASA

    International Nuclear Information System (INIS)

    Brunner, W.; Brichzin, K.; Sach, E.

    1981-06-01

    For NASA's Project Solar Maximum Mission-SMM (launch 14.2.80) a Gamma Ray Detector was developed, manufactured and tested to measure solar high energetic Gamma rays and Neutron fluxes within the energy range 10-160 MeV, 4,43 MeV amd 2,23 MeV. The main components of the sensor are 7 NaI crystals 3 x 3 and a CsI crystal 30 cm diameter x 7,5 cm. The rejection of charged particles is done by two plasitc scintillators and 4 CsI-shields. From the beginning of the mission the experiment is working fully successfull. (orig.) [de

  9. Global view of F-region electron density and temperature at solar maximum

    International Nuclear Information System (INIS)

    Brace, L.H.; Theis, R.F.; Hoegy, W.R.

    1982-01-01

    Dynamics Explorer-2 is permitting the first measurements of the global structure of the F-regions at very high levels of solar activity (S>200). Selected full orbits of Langmuir probe measurements of electron temperature, T/sub e/, and density, N/sub e/, are shown to illustrate this global structure and some of the ionospheric features that are the topic of other papers in this issue. The ionospheric thermal structure is of particular interest because T/sub e/ is a sensitive indicator of the coupling of magnetospheric energy into the upper atmosphere. A comparison of these heating effects with those observed at solar minimum shows that the magnetospheric sources are more important at solar maximum, as might have been expected. Heating at the cusp, the auroral oval and the plasma-pause is generally both greater and more variable. Electron cooling rate calculations employing low latitude measurements indicate that solar extreme ultraviolet heating of the F region at solar maximum is enhanced by a factor that is greater than the increase in solar flux. Some of this enhanced electron heating arises from the increase in electron heating efficiency at the higher N/sub e/ of solar maximum, but this appears insufficient to completely resolve the discrepancy

  10. The Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission

    Science.gov (United States)

    Woodgate, B. E.; Brandt, J. C.; Kalet, M. W.; Kenny, P. J.; Tandberg-Hanssen, E. A.; Bruner, E. C.; Beckers, J. M.; Henze, W.; Knox, E. D.; Hyder, C. L.

    1980-01-01

    The Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission spacecraft is described, including the experiment objectives, system design, performance, and modes of operation. The instrument operates in the wavelength range 1150-3600 A with better than 2 arcsec spatial resolution, raster range 256 x 256 sq arcsec, and 20 mA spectral resolution in second order. Observations can be made with specific sets of four lines simultaneously, or with both sides of two lines simultaneously for velocity and polarization. A rotatable retarder can be inserted into the spectrometer beam for measurement of Zeeman splitting and linear polarization in the transition region and chromosphere.

  11. The ultraviolet spectrometer and polarimeter on the solar maximum mission

    International Nuclear Information System (INIS)

    Woodgate, B.E.; Brandt, J.C.; Kalet, M.W.; Kenny, P.J.; Beckers, J.M.; Henze, W.; Hyder, C.L.; Knox, E.D.

    1980-01-01

    The Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission spacecraft is described, including the experiment objectives, system design. performance, and modes of operation. The instrument operates in the wavelength range 1150-3600 Angstreom with better than 2 arc sec spatial resolution, raster range 256 x 256 arc sec 2 , and 20 m Angstroem spectral resolution in second order. Observations can be made with specific sets of 4 lines simultaneously, or with both sides of 2 lines simultaneously for velocity and polarization. A rotatable retarder can be inserted into the spectrometer beam for measurement of Zeeman splitting and linear polarization in the transition region and chromosphere. (orig.)

  12. YOHKOH Observations at the Y2K Solar Maximum

    Science.gov (United States)

    Aschwanden, M. J.

    1999-05-01

    Yohkoh will provide simultaneous co-aligned soft X-ray and hard X-ray observations of solar flares at the coming solar maximum. The Yohkoh Soft X-ray Telescope (SXT) covers the approximate temperature range of 2-20 MK with a pixel size of 2.46\\arcsec, and thus complements ideally the EUV imagers sensitive in the 1-2 MK plasma, such as SoHO/EIT and TRACE. The Yohkoh Hard X-ray Telescope (HXT) offers hard X-ray imaging at 20-100 keV at a time resolution of down to 0.5 sec for major events. In this paper we review the major SXT and HXT results from Yohkoh solar flare observations, and anticipate some of the key questions that can be addressed through joint observations with other ground and space-based observatories. This encompasses the dynamics of flare triggers (e.g. emerging flux, photospheric shear, interaction of flare loops in quadrupolar geometries, large-scale magnetic reconfigurations, eruption of twisted sigmoid structures, coronal mass ejections), the physics of particle dynamics during flares (acceleration processes, particle propagation, trapping, and precipitation), and flare plasma heating processes (chromospheric evaporation, coronal energy loss by nonthermal particles). In particular we will emphasize on how Yohkoh data analysis is progressing from a qualitative to a more quantitative science, employing 3-dimensional modeling and numerical simulations.

  13. The solar wind at solar maximum: comparisons of EISCAT IPS and in situ observations

    Directory of Open Access Journals (Sweden)

    A. R. Breen

    Full Text Available The solar maximum solar wind is highly structured in latitude, longitude and in time. Coronal measurements show a very high degree of variability, with large variations that are less apparent within in situ spacecraft measurements. Interplanetary scintillation (IPS observations from EISCAT, covering distances from 20 to 100 solar radii (RS, are an ideal source of information on the inner solar wind and can be used, therefore, to cast light on its evolution with distance from the Sun. Earlier comparisons of in situ and IPS measurements under solar minimum conditions showed good large-scale agreement, particularly in the fast wind. In this study we attempt a quantitative comparison of measurements made over solar maximum by EISCAT (20–100 RS and the Wind and Ulysses spacecraft (at 215 RS and 300–1000 RS, respectively. The intervals studied were August–September 1999, May 2000, September 2000 and May 2001, the last-named being the period of the second Ulysses fast latitude scan. Both ballistic and – when possible – MHD/ballistic hybrid models were used to relate the data sets, and we compare the results obtained from these two mapping methods. The results of this study suggest that solar wind velocities measured in situ were less variable than those estimated from IPS measurements closer to the Sun, with the greatest divergence between IPS velocities and in situ measurements occurring in regions where steep longitudinal velocity gradients were seen in situ. We suggest that the interaction between streams of solar wind with different velocities leads to "smoothing" of solar wind velocities between 30–60 RS and 1 AU, and that this process continues at greater distances from the Sun.

    Key words. Interplanetary physics (solar wind plasma; sources of the solar wind; instruments and techniques

  14. Attitude sensor alignment calibration for the solar maximum mission

    Science.gov (United States)

    Pitone, Daniel S.; Shuster, Malcolm D.

    1990-01-01

    An earlier heuristic study of the fine attitude sensors for the Solar Maximum Mission (SMM) revealed a temperature dependence of the alignment about the yaw axis of the pair of fixed-head star trackers relative to the fine pointing Sun sensor. Here, new sensor alignment algorithms which better quantify the dependence of the alignments on the temperature are developed and applied to the SMM data. Comparison with the results from the previous study reveals the limitations of the heuristic approach. In addition, some of the basic assumptions made in the prelaunch analysis of the alignments of the SMM are examined. The results of this work have important consequences for future missions with stringent attitude requirements and where misalignment variations due to variations in the temperature will be significant.

  15. Maximum power point tracking of partially shaded solar photovoltaic arrays

    Energy Technology Data Exchange (ETDEWEB)

    Roy Chowdhury, Shubhajit; Saha, Hiranmay [IC Design and Fabrication Centre, Department of Electronics and Telecommunication Engineering, Jadavpur University (India)

    2010-09-15

    The paper presents the simulation and hardware implementation of maximum power point (MPP) tracking of a partially shaded solar photovoltaic (PV) array using a variant of Particle Swarm Optimization known as Adaptive Perceptive Particle Swarm Optimization (APPSO). Under partially shaded conditions, the photovoltaic (PV) array characteristics get more complex with multiple maxima in the power-voltage characteristic. The paper presents an algorithmic technique to accurately track the maximum power point (MPP) of a PV array using an APPSO. The APPSO algorithm has also been validated in the current work. The proposed technique uses only one pair of sensors to control multiple PV arrays. This result in lower cost and higher accuracy of 97.7% compared to earlier obtained accuracy of 96.41% using Particle Swarm Optimization. The proposed tracking technique has been mapped onto a MSP430FG4618 microcontroller for tracking and control purposes. The whole system based on the proposed has been realized on a standard two stage power electronic system configuration. (author)

  16. Formation of a strong southward IMF near the solar maximum of cycle 23

    Directory of Open Access Journals (Sweden)

    S. Watari

    2004-01-01

    Full Text Available We analyzed observations of the solar activities and the solar wind parameters associated with large geomagnetic storms near the maximum of solar cycle 23. This analysis showed that strong southward interplanetary magnetic fields (IMFs, formed through interaction between an interplanetary disturbance, and background solar wind or between interplanetary disturbances are an important factor in the occurrence of intense geomagnetic storms. Based on our analysis, we seek to improve our understanding of the physical processes in which large negative Bz's are created which will lead to improving predictions of space weather.

    Key words. Interplanetary physics (Flare and stream dynamics; Interplanetary magnetic fields; Interplanetary shocks

  17. The effects of the pre-reversal ExB drift, the EIA asymmetry, and magnetic activity on the equatorial spread F during solar maximum

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-03-01

    Full Text Available We use a digisonde at Jicamarca and a chain of GPS receivers on the west side of South America to investigate the effects of the pre-reversal enhancement (PRE in ExB drift, the asymmetry (Ia of equatorial ionization anomaly (EIA, and the magnetic activity (Kp on the generation of equatorial spread F (ESF. Results show that the ESF appears frequently in summer (November, December, January, and February and equinoctial (March, April, September, and October months, but rarely in winter (May, June, July, and August months. The seasonal variation in the ESF is associated with those in the PRE ExB drift and Ia. The larger ExB drift (>20m/s and smaller |Ia| (<0.3 in summer and equinoctial months provide a preferable condition to development the ESF. Conversely, the smaller ExB drift and larger |Ia| are responsible for the lower ESF occurrence in winter months. Regarding the effects of magnetic activity, the ESF occurrence decreases with increasing Kp in the equinoctial and winter months, but not in the summer months. Furthermore, the larger and smaller ExB drifts are presented under the quiet (Kp<3 and disturbed (Kp≥3 conditions, respectively. These results indicate that the suppression in ESF and the decrease in ExB drifts are mainly caused by the decrease in the eastward electric field.

  18. The effects of the pre-reversal ExB drift, the EIA asymmetry, and magnetic activity on the equatorial spread F during solar maximum

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-03-01

    Full Text Available We use a digisonde at Jicamarca and a chain of GPS receivers on the west side of South America to investigate the effects of the pre-reversal enhancement (PRE in ExB drift, the asymmetry (Ia of equatorial ionization anomaly (EIA, and the magnetic activity (Kp on the generation of equatorial spread F (ESF. Results show that the ESF appears frequently in summer (November, December, January, and February and equinoctial (March, April, September, and October months, but rarely in winter (May, June, July, and August months. The seasonal variation in the ESF is associated with those in the PRE ExB drift and Ia. The larger ExB drift (>20m/s and smaller |Ia| (<0.3 in summer and equinoctial months provide a preferable condition to development the ESF. Conversely, the smaller ExB drift and larger |Ia| are responsible for the lower ESF occurrence in winter months. Regarding the effects of magnetic activity, the ESF occurrence decreases with increasing Kp in the equinoctial and winter months, but not in the summer months. Furthermore, the larger and smaller ExB drifts are presented under the quiet (Kp<3 and disturbed (Kp≥3 conditions, respectively. These results indicate that the suppression in ESF and the decrease in ExB drifts are mainly caused by the decrease in the eastward electric field.

  19. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, Maxim [Physics Department, The Catholic University of America, Washington, DC (United States); Airapetian, Vladimir [Department of Physics and Astronomy, George Mason University, Fairfax, VA (United States); NASA/Goddard Space Flight Center, Code 671, Greenbelt, MD (United States); Lin, Haosheng, E-mail: vladimir.airapetian@nasa.gov [College of Natural Sciences, Institute for Astronomy, University of Hawaii at Manoa, Pukalani, HI (United States)

    2016-08-09

    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 R{sub ⊙} using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 Å band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below ~2.5 R{sub ⊙}. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  20. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Directory of Open Access Journals (Sweden)

    Maxim Kramar

    2016-08-01

    Full Text Available Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131 to retrieve and analyze the three-dimensional (3D coronal electron density in the range of heights from $1.5$ to $4 R_odot$ using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 AA band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below $sim 2.5 R_odot$. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  1. Physics of solar activity

    Science.gov (United States)

    Sturrock, Peter A.

    1993-01-01

    The aim of the research activity was to increase our understanding of solar activity through data analysis, theoretical analysis, and computer modeling. Because the research subjects were diverse and many researchers were supported by this grant, a select few key areas of research are described in detail. Areas of research include: (1) energy storage and force-free magnetic field; (2) energy release and particle acceleration; (3) radiation by nonthermal electrons; (4) coronal loops; (5) flare classification; (6) longitude distributions of flares; (7) periodicities detected in the solar activity; (8) coronal heating and related problems; and (9) plasma processes.

  2. Changes in atmospheric circulation between solar maximum and minimum conditions in winter and summer

    Science.gov (United States)

    Lee, Jae Nyung

    2008-10-01

    Statistically significant climate responses to the solar variability are found in Northern Annular Mode (NAM) and in the tropical circulation. This study is based on the statistical analysis of numerical simulations with ModelE version of the chemistry coupled Goddard Institute for Space Studies (GISS) general circulation model (GCM) and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. The low frequency large scale variability of the winter and summer circulation is described by the NAM, the leading Empirical Orthogonal Function (EOF) of geopotential heights. The newly defined seasonal annular modes and its dynamical significance in the stratosphere and troposphere in the GISS ModelE is shown and compared with those in the NCEP/NCAR reanalysis. In the stratosphere, the summer NAM obtained from NCEP/NCAR reanalysis as well as from the ModelE simulations has the same sign throughout the northern hemisphere, but shows greater variability at low latitudes. The patterns in both analyses are consistent with the interpretation that low NAM conditions represent an enhancement of the seasonal difference between the summer and the annual averages of geopotential height, temperature and velocity distributions, while the reverse holds for high NAM conditions. Composite analysis of high and low NAM cases in both the model and observation suggests that the summer stratosphere is more "summer-like" when the solar activity is near a maximum. This means that the zonal easterly wind flow is stronger and the temperature is higher than normal. Thus increased irradiance favors a low summer NAM. A quantitative comparison of the anti-correlation between the NAM and the solar forcing is presented in the model and in the observation, both of which show lower/higher NAM index in solar maximum/minimum conditions. The summer NAM in the troposphere obtained from NCEP/NCAR reanalysis has a dipolar zonal structure with maximum

  3. Active solar information dissemination activities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The principal objective of the project has been the development of an information dissemination strategy for the UK active solar heating industry. The project has also aimed to prepare the industry for the implementation of such a strategy and to produce initial information materials to support the early stages of the implementation process. (author)

  4. Maximum-power-point tracking control of solar heating system

    KAUST Repository

    Huang, Bin-Juine; Ton, Wei-Zhe; Wu, Chen-Chun; Ko, Hua-Wei; Chang, Hsien-Shun; Yen, Rue-Her; Wang, Jiunn-Cherng

    2012-01-01

    was used to determine the instantaneous tracking target Q max(t). The system transfer-function model of solar heating system was also derived experimentally using a step response test and used in the design of tracking feedback control system. The PI

  5. Magnetohydrodynamic process in solar activity

    Directory of Open Access Journals (Sweden)

    Jingxiu Wang

    2014-01-01

    Full Text Available Magnetohydrodynamics is one of the major disciplines in solar physics. Vigorous magnetohydrodynamic process is taking place in the solar convection zone and atmosphere. It controls the generating and structuring of the solar magnetic fields, causes the accumulation of magnetic non-potential energy in the solar atmosphere and triggers the explosive magnetic energy release, manifested as violent solar flares and coronal mass ejections. Nowadays detailed observations in solar astrophysics from space and on the ground urge a great need for the studies of magnetohydrodynamics and plasma physics to achieve better understanding of the mechanism or mechanisms of solar activity. On the other hand, the spectacular solar activity always serves as a great laboratory of magnetohydrodynamics. In this article, we reviewed a few key unresolved problems in solar activity studies and discussed the relevant issues in solar magnetohydrodynamics.

  6. 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.

  7. Manifestation of solar activity in solar wind particle flux density

    International Nuclear Information System (INIS)

    Kovalenko, V.A.

    1988-01-01

    An analysis has been made of the origin of long-term variations in flux density of solar wind particles (nv) for different velocity regimes. The study revealed a relationship of these variations to the area of the polar coronal holes (CH). It is shown that within the framework of the model under development, the main longterm variations of nv are a result of the latitude redistribution of the solar wind mass flux in the heliosphere and are due to changes in the large-scale geometry of the solar plasma flow in the corona. A study has been made of the variations of nv for high speed solar wind streams. It is found that nv in high speed streams which are formed in CH, decreases from minimum to maximum solar activity. The analysis indicates that this decrease is attributable to the magnetic field strength increase in coronal holes. It has been found that periods of rapid global changes of background magnetic fields on the Sun are accompanied by a reconfiguration of coronal magnetic fields, rapid changes in the length of quiescent filaments, and by an increase in the density of the particle flux of a high speed solar wind. It has been established that these periods precede the formation of CH, corresponding to the increase in solar wind velocity near the Earth and to enhancement of the level of geomagnetic disturbance. (author)

  8. The Effects of Solar Maximum on the Earth's Satellite Population and Space Situational Awareness

    Science.gov (United States)

    Johnson, Nicholas L.

    2012-01-01

    The rapidly approaching maximum of Solar Cycle 24 will have wide-ranging effects not only on the number and distribution of resident space objects, but also on vital aspects of space situational awareness, including conjunction assessment processes. The best known consequence of high solar activity is an increase in the density of the thermosphere, which, in turn, increases drag on the vast majority of objects in low Earth orbit. The most prominent evidence of this is seen in a dramatic increase in space object reentries. Due to the massive amounts of new debris created by the fragmentations of Fengyun-1C, Cosmos 2251 and Iridium 33 during the recent period of Solar Minimum, this effect might reach epic levels. However, space surveillance systems are also affected, both directly and indirectly, historically leading to an increase in the number of lost satellites and in the routine accuracy of the calculation of their orbits. Thus, at a time when more objects are drifting through regions containing exceptionally high-value assets, such as the International Space Station and remote sensing satellites, their position uncertainties increase. In other words, as the possibility of damaging and catastrophic collisions increases, our ability to protect space systems is degraded. Potential countermeasures include adjustments to space surveillance techniques and the resetting of collision avoidance maneuver thresholds.

  9. Comparison of candidate solar array maximum power utilization approaches. [for spacecraft propulsion

    Science.gov (United States)

    Costogue, E. N.; Lindena, S.

    1976-01-01

    A study was made of five potential approaches that can be utilized to detect the maximum power point of a solar array while sustaining operations at or near maximum power and without endangering stability or causing array voltage collapse. The approaches studied included: (1) dynamic impedance comparator, (2) reference array measurement, (3) onset of solar array voltage collapse detection, (4) parallel tracker, and (5) direct measurement. The study analyzed the feasibility and adaptability of these approaches to a future solar electric propulsion (SEP) mission, and, specifically, to a comet rendezvous mission. Such missions presented the most challenging requirements to a spacecraft power subsystem in terms of power management over large solar intensity ranges of 1.0 to 3.5 AU. The dynamic impedance approach was found to have the highest figure of merit, and the reference array approach followed closely behind. The results are applicable to terrestrial solar power systems as well as to other than SEP space missions.

  10. Solar collector manufacturing activity, 1990

    International Nuclear Information System (INIS)

    1992-01-01

    The Solar Collector Manufacturing Activity 1990 report prepared by the Energy Information Administration (EIA) presents summary and detailed data provided by domestic manufacturers on shipments of solar thermal collectors and photovoltaic cells and modules. Summary data on solar thermal collector shipments are presented for the period 1974 through 1990. Summary data on photovoltaic cell and module shipments are presented for the period 1982 through 1990. Detailed information for solar thermal collectors and photovoltaic cells and modules are presented for 1990

  11. Ultraviolet spectrometer and polarimeter (UVSP) software development and hardware tests for the solar maximum mission

    Science.gov (United States)

    Bruner, M. E.; Haisch, B. M.

    1986-01-01

    The Ultraviolet Spectrometer/Polarimeter Instrument (UVSP) for the Solar Maximum Mission (SMM) was based on the re-use of the engineering model of the high resolution ultraviolet spectrometer developed for the OSO-8 mission. Lockheed assumed four distinct responsibilities in the UVSP program: technical evaluation of the OSO-8 engineering model; technical consulting on the electronic, optical, and mechanical modifications to the OSO-8 engineering model hardware; design and development of the UVSP software system; and scientific participation in the operations and analysis phase of the mission. Lockheed also provided technical consulting and assistance with instrument hardware performance anomalies encountered during the post launch operation of the SMM observatory. An index to the quarterly reports delivered under the contract are contained, and serves as a useful capsule history of the program activity.

  12. NASA's search for the solar connection. I. [OSO Skylab, Solar Maximum Mission

    Science.gov (United States)

    Chapman, R. W.

    1979-01-01

    NASA's solar research, which leans toward the study of the sun as a star, is surveyed. The Orbiting Solar Observatory (OSO) program is covered, which yielded data such as spectras of 140-400 A wavelength of the entire solar disk. Attention is also given to the results obtained by Skylab, such as data showing that whenever a large coronal hole exists near the sun's equator, a stream of high-speed solar wind will be observed at the earth. Finally areas of future research, such as a concerted study of flare phenomenon, are discussed.

  13. Solar maximum mission: Ground support programs at the Harvard Radio Astronomy Station

    Science.gov (United States)

    Maxwell, A.

    1983-01-01

    Observations of the spectral characteristics of solar radio bursts were made with new dynamic spectrum analyzers of high sensitivity and high reliability, over the frequency range 25-580 MHz. The observations also covered the maximum period of the current solar cycle and the period of international cooperative programs designated as the Solar Maximum Year. Radio data on shock waves generated by solar flares were combined with optical data on coronal transients, taken with equipment on the SMM and other satellites, and then incorporated into computer models for the outward passage of fast-mode MHD shocks through the solar corona. The MHD models are non-linear, time-dependent and for the most recent models, quasi-three-dimensional. They examine the global response of the corona for different types of input pulses (thermal, magnetic, etc.) and for different magnetic topologies (for example, open and closed fields). Data on coronal shocks and high-velocity material ejected from solar flares have been interpreted in terms of a model consisting of three main velocity regimes.

  14. Implementation of Maximum Power Point Tracking (MPPT) Solar Charge Controller using Arduino

    Science.gov (United States)

    Abdelilah, B.; Mouna, A.; KouiderM’Sirdi, N.; El Hossain, A.

    2018-05-01

    the platform Arduino with a number of sensors standard can be used as components of an electronic system for acquiring measures and controls. This paper presents the design of a low-cost and effective solar charge controller. This system includes several elements such as the solar panel converter DC/DC, battery, circuit MPPT using Microcontroller, sensors, and the MPPT algorithm. The MPPT (Maximum Power Point Tracker) algorithm has been implemented using an Arduino Nano with the preferred program. The voltage and current of the Panel are taken where the program implemented will work and using this algorithm that MPP will be reached. This paper provides details on the solar charge control device at the maximum power point. The results include the change of the duty cycle with the change in load and thus mean the variation of the buck converter output voltage and current controlled by the MPPT algorithm.

  15. Modeling of Maximum Power Point Tracking Controller for Solar Power System

    Directory of Open Access Journals (Sweden)

    Aryuanto Soetedjo

    2012-09-01

    Full Text Available In this paper, a Maximum Power Point Tracking (MPPT controller for solar power system is modeled using MATLAB Simulink. The model consists of PV module, buck converter, and MPPT controller. The contribution of the work is in the modeling of buck converter that allowing the input voltage of the converter, i.e. output voltage of PV is changed by varying the duty cycle, so that the maximum power point could be tracked when the environmental changes. The simulation results show that the developed model performs well in tracking the maximum power point (MPP of the PV module using Perturb and Observe (P&O Algorithm.

  16. High-energy solar flare observations at the Y2K maximum

    Science.gov (United States)

    Emslie, A. Gordon

    2000-04-01

    Solar flares afford an opportunity to observe processes associated with the acceleration and propagation of high-energy particles at a level of detail not accessible in any other astrophysical source. I will review some key results from previous high-energy solar flare observations, including those from the Compton Gamma-Ray Observatory, and the problems that they pose for our understanding of energy release and particle acceleration processes in the astrophysical environment. I will then discuss a program of high-energy observations to be carried out during the upcoming 2000-2001 solar maximum that is aimed at addressing and resolving these issues. A key element in this observational program is the High Energy Solar Spectroscopic Imager (HESSI) spacecraft, which will provide imaging spectroscopic observations with spatial, temporal, and energy resolutions commensurate with the physical processes believed to be operating, and will in addition provide the first true gamma-ray spectroscopy of an astrophysical source. .

  17. Deciphering solar magnetic activity: on grand minima in solar activity

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Scott W. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Leamon, Robert J., E-mail: mscott@ucar.edu [Department of Physics, Montana State University, Bozeman, MT (United States)

    2015-07-08

    The Sun provides the energy necessary to sustain our existence. While the Sun provides for us, it is also capable of taking away. The weather and climatic scales of solar evolution and the Sun-Earth connection are not well- understood. There has been tremendous progress in the century since the discovery of solar magnetism—magnetism that ultimately drives the electromagnetic, particulate, and eruptive forcing of our planetary system. There is contemporary evidence of a decrease in solar magnetism, perhaps even indicators of a significant downward trend, over recent decades. Are we entering a minimum in solar activity that is deeper and longer than a typical solar minimum, a “grand minimum”? How could we tell if we are? What is a grand minimum and how does the Sun recover? These are very pertinent questions for modern civilization. In this paper we present a hypothetical demonstration of entry and exit from grand minimum conditions based on a recent analysis of solar features over the past 20 years and their possible connection to the origins of the 11(&ish) year solar activity cycle.

  18. Deciphering Solar Magnetic Activity: On Grand Minima in Solar Activity

    Directory of Open Access Journals (Sweden)

    Scott William Mcintosh

    2015-07-01

    Full Text Available The Sun provides the energy necessary to sustain our existence. While the Sun provides for us, it is also capable of taking away. The weather and climatic scales of solar evolution and the Sun-Earth connection are not well understood. There has been tremendous progress in the century since the discovery of solar magnetism - magnetism that ultimately drives the electromagnetic, particulate and eruptive forcing of our planetary system. There is contemporary evidence of a decrease in solar magnetism, perhaps even indicators of a significant downward trend, over recent decades. Are we entering a minimum in solar activity that is deeper and longer than a typical solar minimum, a grand minimum? How could we tell if we are? What is a grand minimum and how does the Sun recover? These are very pertinent questions for modern civilization. In this paper we present a hypothetical demonstration of entry and exit from grand minimum conditions based on a recent analysis of solar features over the past 20 years and their possible connection to the origins of the 11(-ish year solar activity cycle.

  19. Deciphering Solar Magnetic Activity: On Grand Minima in Solar Activity

    Science.gov (United States)

    Mcintosh, Scott; Leamon, Robert

    2015-07-01

    The Sun provides the energy necessary to sustain our existence. While the Sun provides for us, it is also capable of taking away. The weather and climatic scales of solar evolution and the Sun-Earth connection are not well understood. There has been tremendous progress in the century since the discovery of solar magnetism - magnetism that ultimately drives the electromagnetic, particulate and eruptive forcing of our planetary system. There is contemporary evidence of a decrease in solar magnetism, perhaps even indicators of a significant downward trend, over recent decades. Are we entering a minimum in solar activity that is deeper and longer than a typical solar minimum, a "grand minimum"? How could we tell if we are? What is a grand minimum and how does the Sun recover? These are very pertinent questions for modern civilization. In this paper we present a hypothetical demonstration of entry and exit from grand minimum conditions based on a recent analysis of solar features over the past 20 years and their possible connection to the origins of the 11(-ish) year solar activity cycle.

  20. Volcanic eruptions and solar activity

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  1. Post flight analysis of NASA standard star trackers recovered from the solar maximum mission

    Science.gov (United States)

    Newman, P.

    1985-01-01

    The flight hardware returned after the Solar Maximum Mission Repair Mission was analyzed to determine the effects of 4 years in space. The NASA Standard Star Tracker would be a good candidate for such analysis because it is moderately complex and had a very elaborate calibration during the acceptance procedure. However, the recovery process extensively damaged the cathode of the image dissector detector making proper operation of the tracker and a comparison with preflight characteristics impossible. Otherwise, the tracker functioned nominally during testing.

  2. 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.

  3. Simulation model of ANN based maximum power point tracking controller for solar PV system

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Anil K.; Singh, Bhupal [Department of Electrical and Electronics Engineering, Ajay Kumar Garg Engineering College, Ghaziabad 201009 (India); Kaushika, N.D.; Agarwal, Niti [School of Research and Development, Bharati Vidyapeeth College of Engineering, A-4 Paschim Vihar, New Delhi 110063 (India)

    2011-02-15

    In this paper the simulation model of an artificial neural network (ANN) based maximum power point tracking controller has been developed. The controller consists of an ANN tracker and the optimal control unit. The ANN tracker estimates the voltages and currents corresponding to a maximum power delivered by solar PV (photovoltaic) array for variable cell temperature and solar radiation. The cell temperature is considered as a function of ambient air temperature, wind speed and solar radiation. The tracker is trained employing a set of 124 patterns using the back propagation algorithm. The mean square error of tracker output and target values is set to be of the order of 10{sup -5} and the successful convergent of learning process takes 1281 epochs. The accuracy of the ANN tracker has been validated by employing different test data sets. The control unit uses the estimates of the ANN tracker to adjust the duty cycle of the chopper to optimum value needed for maximum power transfer to the specified load. (author)

  4. Intelligent Maximum Power Point Tracking Using Fuzzy Logic for Solar Photovoltaic Systems Under Non-Uniform Irradiation Conditions

    OpenAIRE

    P. Selvam; S. Senthil Kumar

    2016-01-01

    Maximum Power Point Tracking (MPPT) has played a vital role to enhance the efficiency of solar photovoltaic (PV) power generation under varying atmospheric temperature and solar irradiation. However, it is hard to track the maximum power point using conventional linear controllers due to the natural inheritance of nonlinear I-V and P-V characteristics of solar PV systems. Fuzzy Logic Controller (FLC) is suitable for nonlinear system control applications and eliminating oscillations, circuit c...

  5. Lower atmosphere of solar flares; Proceedings of the Solar Maximum Mission Symposium, Sunspot, NM, Aug. 20-24, 1985

    International Nuclear Information System (INIS)

    Neidig, D.F.

    1986-01-01

    The topics discussed by the present conference encompass the chromospheric flare phenomenon, white light flares, UV emission and the flare transition region, the flare corona and high energy emissions, stellar flares, and flare energy release and transport. Attention is given to radiative shocks and condensation in flares, impulsive brightening of H-alpha flare points, the structure and response of the chromosphere to radiation backwarming during solar flares, the interpretation of continuum emissions in white light flares, and the radiation properties of solar plasmas. Also discussed are EUV images of a solar flare and C III intensity, an active region survey in H-alpha and X-rays, dynamic thermal plasma conditions in large flares, the evolution of the flare mechanism in dwarf stars, the evidence concerning electron beams in solar flares, the energetics of the nonlinear tearing mode, macroscopic electric fields during two-ribbon flares, and the low temperature signatures of energetic particles

  6. Maximum power point tracking for photovoltaic solar pump based on ANFIS tuning system

    Directory of Open Access Journals (Sweden)

    S. Shabaan

    2018-05-01

    Full Text Available Solar photovoltaic (PV systems are a clean and naturally replenished energy source. PV panels have a unique point which represents the maximum available power and this point depend on the environmental conditions such as temperature and irradiance. A maximum power point tracking (MPPT is therefore necessary for maximum efficiency. In this paper, a study of MPPT for PV water pumping system based on adaptive neuro-fuzzy inference system (ANFIS is discussed. A comparison between the performance of the system with and without MPPT is carried out under varying irradiation and temperature conditions. ANFIS based controller shows fast response with high efficiency at all irradiance and temperature levels making it a powerful technique for non-linear systems as PV modules. Keywords: MPPT, ANFIS, Boost converter, PMDC pump

  7. Properties of an impulsive compact solar flare determined from Solar Maximum Mission X-ray measurements

    Science.gov (United States)

    Linford, G. A.; Wolfson, C. J.

    1988-01-01

    Soft X-ray, hard X-ray magnetogram, and H-alpha data have been analyzed for an impulsive compact solar flare which occurred on May 21, 1985. The derived flare loop dimensions are about 20,000 km length and about 150 km diameter. Measurements of line ratios from the Mg XI ion indicate that the plasma density varied from about 4 x 10 to the 12th/cu cm early in the flare to about 10 to the 12th/cu cm during the flare decay. The initial temperature of this plasma was about 8 x 10 to the 6th K and dropped to about 5 x 10 to the 6th K during the decay phase. The simplest interpretation of the event is one in which the source of the soft X-ray flare emission is confined to a thin loop of very high density.

  8. Properties of an impulsive compact solar flare determined from Solar Maximum Mission X-ray measurements

    International Nuclear Information System (INIS)

    Linford, G.A.; Wolfson, C.J.

    1988-01-01

    Soft X-ray, hard X-ray magnetogram, and H-alpha data have been analyzed for an impulsive compact solar flare which occurred on May 21, 1985. The derived flare loop dimensions are about 20,000 km length and about 150 km diameter. Measurements of line ratios from the Mg XI ion indicate that the plasma density varied from about 4 x 10 to the 12th/cu cm early in the flare to about 10 to the 12th/cu cm during the flare decay. The initial temperature of this plasma was about 8 x 10 to the 6th K and dropped to about 5 x 10 to the 6th K during the decay phase. The simplest interpretation of the event is one in which the source of the soft X-ray flare emission is confined to a thin loop of very high density. 44 references

  9. Properties of an impulsive compact solar flare determined from Solar Maximum Mission X-ray measurements

    Energy Technology Data Exchange (ETDEWEB)

    Linford, G.A.; Wolfson, C.J.

    1988-08-01

    Soft X-ray, hard X-ray magnetogram, and H-alpha data have been analyzed for an impulsive compact solar flare which occurred on May 21, 1985. The derived flare loop dimensions are about 20,000 km length and about 150 km diameter. Measurements of line ratios from the Mg XI ion indicate that the plasma density varied from about 4 x 10 to the 12th/cu cm early in the flare to about 10 to the 12th/cu cm during the flare decay. The initial temperature of this plasma was about 8 x 10 to the 6th K and dropped to about 5 x 10 to the 6th K during the decay phase. The simplest interpretation of the event is one in which the source of the soft X-ray flare emission is confined to a thin loop of very high density. 44 references.

  10. Predicting Maximum Sunspot Number in Solar Cycle 24 Nipa J Bhatt ...

    Indian Academy of Sciences (India)

    Key words. Sunspot number—precursor prediction technique—geo- magnetic activity index aa. 1. Introduction. Predictions of solar and geomagnetic activities are important for various purposes, including the operation of low-earth orbiting satellites, operation of power grids on. Earth, and satellite communication systems.

  11. Parametric characteristics of a solar thermophotovoltaic system at the maximum efficiency

    International Nuclear Information System (INIS)

    Liao, Tianjun; Chen, Xiaohang; Yang, Zhimin; Lin, Bihong; Chen, Jincan

    2016-01-01

    Graphical abstract: A model of the far-field TPVC driven by solar energy, which consists of an optical concentrator, an absorber, an emitter, and a PV cell and is simply referred as to the far-field STPVS. - Highlights: • A model of the far-field solar thermophotovoltaic system (STPVS) is established. • External and internal irreversible losses are considered. • The maximum efficiency of the STPVS is calculated. • Optimal values of key parameters at the maximum efficiency are determined. • Effects of the concentrator factor on the performance of the system are discussed. - Abstract: A model of the solar thermophotovoltaic system (STPVS) consisting of an optical concentrator, a thermal absorber, an emitter, and a photovoltaic (PV) cell is proposed, where the far-field thermal emission between the emitter and the PV cell, the radiation losses from the absorber and emitter to the environment, the reflected loss from the absorber, and the finite-rate heat exchange between the PV cell and the environment are taken into account. Analytical expressions for the power output of and overall efficiency of the STPVS are derived. By solving thermal equilibrium equations, the operating temperatures of the emitter and PV cell are determined and the maximum efficiency of the system is calculated numerically for given values of the output voltage of the PV cell and the ratio of the front surface area of the absorber to that of the emitter. For different bandgaps, the maximum efficiencies of the system are calculated and the corresponding optimum values of several operating parameters are obtained. The effects of the concentrator factor on the optimum performance of the system are also discussed.

  12. Performance characteristics and parametric choices of a solar thermophotovoltaic cell at the maximum efficiency

    International Nuclear Information System (INIS)

    Dong, Qingchun; Liao, Tianjun; Yang, Zhimin; Chen, Xiaohang; Chen, Jincan

    2017-01-01

    Graphical abstract: The overall model of the solar thermophotovoltaic cell (STPVC) composed of an optical lens, an absorber, an emitter, and a photovoltaic (PV) cell with an integrated back-side reflector is updated to include various irreversible losses. - Highlights: • A new model of the irreversible solar thermophotovoltaic system is proposed. • The material and structure parameters of the system are considered. • The performance characteristics at the maximum efficiency are revealed. • The optimal values of key parameters are determined. • The system can obtain a large efficiency under a relative low concentration ratio. - Abstract: The overall model of the solar thermophotovoltaic cell (STPVC) composed of an optical lens, an absorber, an emitter, and a photovoltaic (PV) cell with an integrated back-side reflector is updated to include various irreversible losses. The power output and efficiency of the cell are analytically derived. The performance characteristics of the STPVC at the maximum efficiency are revealed. The optimum values of several important parameters, such as the voltage output of the PV cell, the area ratio of the absorber to the emitter, and the band-gap of the semiconductor material, are determined. It is found that under the condition of a relative low concentration ratio, the optimally designed STPVC can obtain a relative large efficiency.

  13. A Maximum Likelihood Approach to Determine Sensor Radiometric Response Coefficients for NPP VIIRS Reflective Solar Bands

    Science.gov (United States)

    Lei, Ning; Chiang, Kwo-Fu; Oudrari, Hassan; Xiong, Xiaoxiong

    2011-01-01

    Optical sensors aboard Earth orbiting satellites such as the next generation Visible/Infrared Imager/Radiometer Suite (VIIRS) assume that the sensors radiometric response in the Reflective Solar Bands (RSB) is described by a quadratic polynomial, in relating the aperture spectral radiance to the sensor Digital Number (DN) readout. For VIIRS Flight Unit 1, the coefficients are to be determined before launch by an attenuation method, although the linear coefficient will be further determined on-orbit through observing the Solar Diffuser. In determining the quadratic polynomial coefficients by the attenuation method, a Maximum Likelihood approach is applied in carrying out the least-squares procedure. Crucial to the Maximum Likelihood least-squares procedure is the computation of the weight. The weight not only has a contribution from the noise of the sensor s digital count, with an important contribution from digitization error, but also is affected heavily by the mathematical expression used to predict the value of the dependent variable, because both the independent and the dependent variables contain random noise. In addition, model errors have a major impact on the uncertainties of the coefficients. The Maximum Likelihood approach demonstrates the inadequacy of the attenuation method model with a quadratic polynomial for the retrieved spectral radiance. We show that using the inadequate model dramatically increases the uncertainties of the coefficients. We compute the coefficient values and their uncertainties, considering both measurement and model errors.

  14. Solar active region display system

    Science.gov (United States)

    Golightly, M.; Raben, V.; Weyland, M.

    2003-04-01

    The Solar Active Region Display System (SARDS) is a client-server application that automatically collects a wide range of solar data and displays it in a format easy for users to assimilate and interpret. Users can rapidly identify active regions of interest or concern from color-coded indicators that visually summarize each region's size, magnetic configuration, recent growth history, and recent flare and CME production. The active region information can be overlaid onto solar maps, multiple solar images, and solar difference images in orthographic, Mercator or cylindrical equidistant projections. Near real-time graphs display the GOES soft and hard x-ray flux, flare events, and daily F10.7 value as a function of time; color-coded indicators show current trends in soft x-ray flux, flare temperature, daily F10.7 flux, and x-ray flare occurrence. Through a separate window up to 4 real-time or static graphs can simultaneously display values of KP, AP, daily F10.7 flux, GOES soft and hard x-ray flux, GOES >10 and >100 MeV proton flux, and Thule neutron monitor count rate. Climatologic displays use color-valued cells to show F10.7 and AP values as a function of Carrington/Bartel's rotation sequences - this format allows users to detect recurrent patterns in solar and geomagnetic activity as well as variations in activity levels over multiple solar cycles. Users can customize many of the display and graph features; all displays can be printed or copied to the system's clipboard for "pasting" into other applications. The system obtains and stores space weather data and images from sources such as the NOAA Space Environment Center, NOAA National Geophysical Data Center, the joint ESA/NASA SOHO spacecraft, and the Kitt Peak National Solar Observatory, and can be extended to include other data series and image sources. Data and images retrieved from the system's database are converted to XML and transported from a central server using HTTP and SOAP protocols, allowing

  15. Temperature dependence of attitude sensor coalignments on the Solar Maximum Mission (SMM)

    Science.gov (United States)

    Pitone, D. S.; Eudell, A. H.; Patt, F. S.

    1990-01-01

    The temperature correlation of the relative coalignment between the fine-pointing sun sensor and fixed-head star trackers measured on the Solar Maximum Mission (SMM) is analyzed. An overview of the SMM, including mission history and configuration, is given. Possible causes of the misalignment variation are discussed, with focus placed on spacecraft bending due to solar-radiation pressure, electronic or mechanical changes in the sensors, uncertainty in the attitude solutions, and mounting-plate expansion and contraction due to thermal effects. Yaw misalignment variation from the temperature profile is assessed, and suggestions for spacecraft operations are presented, involving methods to incorporate flight measurements of the temperature-versus-alignment function and its variance in operational procedures and the spacecraft structure temperatures in the attitude telemetry record.

  16. Solar Panel System for Street Light Using Maximum Power Point Tracking (MPPT Technique

    Directory of Open Access Journals (Sweden)

    Wiedjaja A.

    2014-03-01

    Full Text Available Solar energy is one form of the renewable energy which is very abundant in regions close to the equator. One application of solar energy is for street light. This research focuses on using the maximum power point tracking technique (MPPT, particularly the perturb and observe (P&O algorithm, to charge battery for street light system. The proposed charger circuit can achieve 20.73% higher power efficiency compared to that of non-MPPT charger. We also develop the LED driver circuit for the system which can achieve power efficiency up to 91.9% at a current of 1.06 A. The proposed street lightning system can be implemented with a relatively low cost for public areas.

  17. Thermospheric response observed over Fritz peak, Colorado, during two large geomagnetic storms near solar cycle maximum

    International Nuclear Information System (INIS)

    Hernandez, G.; Roble, R.G.; Ridley, E.C.; Allen, J.H.

    1982-01-01

    Nightime thermospheric winds and temperatures have been measured over Fritz Peak Observatory, Colorado (39.9 0 N, 105.5 0 W), with a high resolution Fabry-Perot spectrometer. The winds and temperatures are obtained from the Doppler shifts and line profiles of the (O 1) 15,867K (630 nm) line emission. Measurements made during two large geomagnetic storm periods near solar cycle maximum reveal a thermospheric response to the heat and momentum sources associated with these storms that is more complex than the ones measured near solar cycle minimum. In the earlier measurements made during solar cycle minimum, the winds to the north of Fritz Peak Observatory had an enhanced equatorward component and the winds to the south were also equatorward, usually with smaller velocities. The winds measured to the east and west of the observatory both had an enhanced westward wind component. For the two large storms near the present solar cycle maximum period converging winds are observed in each of the cardinal directions from Fritz Peak Observatory. These converging winds with speeds of hundreds of meters per second last for several hours. The measured neutral gas temperature in each of the directions also increases several hundred degrees Kelvin. Numerical experiments done with the NCAR thermospheric general circulation model (TGCM) suggest that the winds to the east and north of the station are driven by high-latitude heating and enhanced westward ion drag associated with magnetospheric convection. The cause of the enhanced poleward and eastward winds measured to the south and west of Fritz Peak Observatory, respectively, is not known. During geomagnetic quiet conditions the circulation is typically from the soutwest toward the northeast in the evening hours

  18. The Possibility of Functioning at Maximum Power for Solar Photovoltaic - Electric Battery Systems

    Directory of Open Access Journals (Sweden)

    Chioncel Cristian Paul

    2013-01-01

    Full Text Available The paper presents the functioning of a solar photovoltaic module(PVM that debits direct to on electric battery (EB. By a good adaptingof PVM to EB, so that the no load voltage of the two components (PVMand EB are well suited, during a day the energy value can be reachednear to the maximum possible value, when the PVM functions in themaximum power point (MPP. The proposed solution is much moreeconomic than the classical: PVM + DC – DC + EB because the directcurrent - direct current power converter, is not necessary (DC - DC.

  19. Double-tailored nonimaging reflector optics for maximum-performance solar concentration.

    Science.gov (United States)

    Goldstein, Alex; Gordon, Jeffrey M

    2010-09-01

    A nonimaging strategy that tailors two mirror contours for concentration near the étendue limit is explored, prompted by solar applications where a sizable gap between the optic and absorber is required. Subtle limitations of this simultaneous multiple surface method approach are derived, rooted in the manner in which phase space boundaries can be tailored according to the edge-ray principle. The fundamental categories of double-tailored reflective optics are identified, only a minority of which can pragmatically offer maximum concentration at high collection efficiency. Illustrative examples confirm that acceptance half-angles as large as 30 mrad can be realized at a flux concentration of approximately 1000.

  20. Abundance variations in solar active regions

    Science.gov (United States)

    Strong, K. T.; Lemen, J. R.; Linford, G. A.

    1991-01-01

    The diversity in the published values of coronal abundances is unsettling, especially as the range of results seems to be beyond the quoted uncertainties. Measurements of the relative abundance of iron and neon derived from soft X-ray spectra of active regions are presented. From a data base of over 200 spectra taken by the Solar Maximum Mission Flat Crystal Spectrometer, it is found that the relative abundance can vary by as much as a factor of about 7 and can change on timescales of less than 1 h.

  1. CAWSES November 7-8, 2004, Superstorm: Complex Solar and Interplanetary Features in the Post-Solar Maximum Phase

    Science.gov (United States)

    Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.; Kozyra, J. U.

    2008-01-01

    The complex interplanetary structures during 7 to 8 Nov 2004 are analyzed to identify their properties as well as resultant geomagnetic effects and the solar origins. Three fast forward shocks, three directional discontinuities and two reverse waves were detected and analyzed in detail. The three fast forward shocks 'pump' up the interplanetary magnetic field from a value of approx.4 nT to 44 nT. However, the fields after the shocks were northward, and magnetic storms did not result. The three ram pressure increases were associated with major sudden impulses (SI + s) at Earth. A magnetic cloud followed the third forward shock and the southward Bz associated with the latter was responsible for the superstorm. Two reverse waves were detected, one at the edge and one near the center of the magnetic cloud (MC). It is suspected that these 'waves' were once reverse shocks which were becoming evanescent when they propagated into the low plasma beta MC. The second reverse wave caused a decrease in the southward component of the IMF and initiated the storm recovery phase. It is determined that flares located at large longitudinal distances from the subsolar point were the most likely causes of the first two shocks without associated magnetic clouds. It is thus unlikely that the shocks were 'blast waves' or that magnetic reconnection eroded away the two associated MCs. This interplanetary/solar event is an example of the extremely complex magnetic storms which can occur in the post-solar maximum phase.

  2. Monitoring of the solar activity and solar energetic particles

    International Nuclear Information System (INIS)

    Akioka, Maki; Kubo, Yuki; Nagatsuma, Tsutomu; Ohtaka, Kazuhiro

    2009-01-01

    Solar activity is the source of various space weather phenomena in geospace and deep space. Solar X-ray radiation in flare, energetic particles, coronal mass ejection (CME) can cause various kind of disturbance near earth space. Therefore, detailed monitoring of the solar activity and its propagation in the interplanetary space is essential task for space weather. For example, solar energetic particle which sometimes affect spacecraft operation and manned space flight, is considered to be produced by solar flares and travelling shockwave caused by flares and CME. The research and development of monitoring technique and system for various solar activity has been an important topic of space weather forecast program in NICT. In this article, we will introduce the real time data acquisitions of STEREO and optical and radio observations of the Sun at Hiraiso Solar Observatory. (author)

  3. Novel high accurate sensorless dual-axis solar tracking system controlled by maximum power point tracking unit of photovoltaic systems

    International Nuclear Information System (INIS)

    Fathabadi, Hassan

    2016-01-01

    Highlights: • Novel high accurate sensorless dual-axis solar tracker. • It has the advantages of both sensor based and sensorless solar trackers. • It does not have the disadvantages of sensor based and sensorless solar trackers. • Tracking error of only 0.11° that is less than the tracking errors of others. • An increase of 28.8–43.6% depending on the seasons in the energy efficiency. - Abstract: In this study, a novel high accurate sensorless dual-axis solar tracker controlled by the maximum power point tracking unit available in almost all photovoltaic systems is proposed. The maximum power point tracking controller continuously calculates the maximum output power of the photovoltaic module/panel/array, and uses the altitude and azimuth angles deviations to track the sun direction where the greatest value of the maximum output power is extracted. Unlike all other sensorless solar trackers, the proposed solar tracking system is a closed loop system which means it uses the actual direction of the sun at any time to track the sun direction, and this is the contribution of this work. The proposed solar tracker has the advantages of both sensor based and sensorless dual-axis solar trackers, but it does not have their disadvantages. Other sensorless solar trackers all are open loop, i.e., they use offline estimated data about the sun path in the sky obtained from solar map equations, so low exactness, cloudy sky, and requiring new data for new location are their problems. A photovoltaic system has been built, and it is experimentally verified that the proposed solar tracking system tracks the sun direction with the tracking error of 0.11° which is less than the tracking errors of other both sensor based and sensorless solar trackers. An increase of 28.8–43.6% depending on the seasons in the energy efficiency is the main advantage of utilizing the proposed solar tracking system.

  4. A New Fuzzy-Based Maximum Power Point Tracker for a Solar Panel Based on Datasheet Values

    Directory of Open Access Journals (Sweden)

    Ali Kargarnejad

    2013-01-01

    Full Text Available Tracking maximum power point of a solar panel is of interest in most of photovoltaic applications. Solar panel modeling is also very interesting exclusively based on manufacturers data. Knowing that the manufacturers generally give the electrical specifications of their products at one operating condition, there are so many cases in which the specifications in other conditions are of interest. In this research, a comprehensive one-diode model for a solar panel with maximum obtainable accuracy is fully developed only based on datasheet values. The model parameters dependencies on environmental conditions are taken into consideration as much as possible. Comparison between real data and simulations results shows that the proposed model has maximum obtainable accuracy. Then a new fuzzy-based controller to track the maximum power point of the solar panel is also proposed which has better response from speed, accuracy and stability point of view respect to the previous common developed one.

  5. Observations of solar flare transition zone plasmas from the Solar Maximum Mission

    Science.gov (United States)

    Cheng, C.-C.; Bruner, E. C.; Tandberg-Hanssen, E.; Woodgate, B. E.; Shine, R. A.; Kenny, P. J.; Henze, W.; Poletto, G.

    1982-01-01

    The spatial and temporal evolution of the Si IV and O IV intensity, density and mass motions in preflare and flare transition zone plasmas are studied for the case of the April 8, 1980 flare. It is found that: (1) the UV flare observed in the Si IV and O IV lines is unambiguously identified as occurring in a low-lying, preexisting transition zone loop which spanned the magnetic neutral line separating a larger leader spot and a newly emerged, isolated spot of opposite polarity; (2) at the onset of the flare, the easternmost footpoint, which was anchored in an isolated spot region of high longitudinal magnetic field gradient, showed sudden, impulsive brightening with large intensity increases; and (3) the release flare energy was transported by way of large-scale connecting field lines to other parts of the active region, producing the hot plasma and H-alpha kernels observed near the trailing spot.

  6. Evaluating Maximum Wind Energy Exploitation in Active Distribution Networks

    DEFF Research Database (Denmark)

    Siano, Pierluigi; Chen, Peiyuan; Chen, Zhe

    2010-01-01

    The increased spreading of distributed and renewable generation requires moving towards active management of distribution networks. In this paper, in order to evaluate maximum wind energy exploitation in active distribution networks, a method based on a multi-period optimal power flow (OPF......) analysis is proposed. Active network management schemes such as coordinated voltage control, energy curtailment and power factor control are integrated in the method in order to investigate their impacts on the maximization of wind energy exploitation. Some case studies, using real data from a Danish...... distribution system, confirmed the effectiveness of the proposed method in evaluating the optimal applications of active management schemes to increase wind energy harvesting without costly network reinforcement for the connection of wind generation....

  7. Geophysical and solar activity indices

    Science.gov (United States)

    Bossy, L.; Lemaire, J.

    1984-04-01

    A large number of geophysicists try to correlate their observations with one or even a series of different geophysical or solar activity indices. Yet the right choice of the most appropriate index with which to correlate depends mainly on our understanding of the physical cause-effect relationship between the new set of observations and the index chosen. This best choice will therefore depend on our good understanding of the methods of measurement and derivation of the adopted index in such correlative studies. It relies also on our awareness of the range of applicability of the indices presently available as well as on our understanding of their limitations. It was to achieve these goals that a series of general lectures on geophysical and solar activity indices was organized by L. Bossy and J. Lemaire (Institut d'Aeronomie Spatiale de Belgique (IASB), Brussels), March 26-29, 1984 at Han-sur-Lesse, Belgium.

  8. Toward maximum transmittance into absorption layers in solar cells: investigation of lossy-film-induced mismatches between reflectance and transmittance extrema.

    Science.gov (United States)

    Chang, Yin-Jung; Lai, Chi-Sheng

    2013-09-01

    The mismatch in film thickness and incident angle between reflectance and transmittance extrema due to the presence of lossy film(s) is investigated toward the maximum transmittance design in the active region of solar cells. Using a planar air/lossy film/silicon double-interface geometry illustrates important and quite opposite mismatch behaviors associated with TE and TM waves. In a typical thin-film CIGS solar cell, mismatches contributed by TM waves in general dominate. The angular mismatch is at least 10° in about 37%-53% of the spectrum, depending on the thickness combination of all lossy interlayers. The largest thickness mismatch of a specific interlayer generally increases with the thickness of the layer itself. Antireflection coating designs for solar cells should therefore be optimized in terms of the maximum transmittance into the active region, even if the corresponding reflectance is not at its minimum.

  9. Maximum power point tracking: a cost saving necessity in solar energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Enslin, J H.R. [Stellenbosch Univ. (South Africa). Dept. of Electrical and Electronic Engineering

    1992-12-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking (MPPT) can improve cost effectiveness, has a higher reliability and can improve the quality of life in remote areas. A high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of between 15 and 25% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply (RAPS) systems. The advantages at large temperature variations and high power rated systems are much higher. Other advantages include optimal sizing and system monitor and control. (author).

  10. Circuit Simulation for Solar Power Maximum Power Point Tracking with Different Buck-Boost Converter Topologies

    Directory of Open Access Journals (Sweden)

    Jaw-Kuen Shiau

    2014-08-01

    Full Text Available The power converter is one of the essential elements for effective use of renewable power sources. This paper focuses on the development of a circuit simulation model for maximum power point tracking (MPPT evaluation of solar power that involves using different buck-boost power converter topologies; including SEPIC, Zeta, and four-switch type buck-boost DC/DC converters. The circuit simulation model mainly includes three subsystems: a PV model; a buck-boost converter-based MPPT system; and a fuzzy logic MPPT controller. Dynamic analyses of the current-fed buck-boost converter systems are conducted and results are presented in the paper. The maximum power point tracking function is achieved through appropriate control of the power switches of the power converter. A fuzzy logic controller is developed to perform the MPPT function for obtaining maximum power from the PV panel. The MATLAB-based Simulink piecewise linear electric circuit simulation tool is used to verify the complete circuit simulation model.

  11. Lifetime predictions for the Solar Maximum Mission (SMM) and San Marco spacecraft

    Science.gov (United States)

    Smith, E. A.; Ward, D. T.; Schmitt, M. W.; Phenneger, M. C.; Vaughn, F. J.; Lupisella, M. L.

    1989-01-01

    Lifetime prediction techniques developed by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) are described. These techniques were developed to predict the Solar Maximum Mission (SMM) spacecraft orbit, which is decaying due to atmospheric drag, with reentry predicted to occur before the end of 1989. Lifetime predictions were also performed for the Long Duration Exposure Facility (LDEF), which was deployed on the 1984 SMM repair mission and is scheduled for retrieval on another Space Transportation System (STS) mission later this year. Concepts used in the lifetime predictions were tested on the San Marco spacecraft, which reentered the Earth's atmosphere on December 6, 1988. Ephemerides predicting the orbit evolution of the San Marco spacecraft until reentry were generated over the final 90 days of the mission when the altitude was less than 380 kilometers. The errors in the predicted ephemerides are due to errors in the prediction of atmospheric density variations over the lifetime of the satellite. To model the time dependence of the atmospheric densities, predictions of the solar flux at the 10.7-centimeter wavelength were used in conjunction with Harris-Priester (HP) atmospheric density tables. Orbital state vectors, together with the spacecraft mass and area, are used as input to the Goddard Trajectory Determination System (GTDS). Propagations proceed in monthly segments, with the nominal atmospheric drag model scaled for each month according to the predicted monthly average value of F10.7. Calibration propagations are performed over a period of known orbital decay to obtain the effective ballistic coefficient. Progagations using plus or minus 2 sigma solar flux predictions are also generated to estimate the despersion in expected reentry dates. Definitive orbits are compared with these predictions as time expases. As updated vectors are received, these are also propagated to reentryto continually update the lifetime predictions.

  12. The Maximum Mass Solar Nebula and the early formation of planets

    Science.gov (United States)

    Nixon, C. J.; King, A. R.; Pringle, J. E.

    2018-03-01

    Current planet formation theories provide successful frameworks with which to interpret the array of new observational data in this field. However, each of the two main theories (core accretion, gravitational instability) is unable to explain some key aspects. In many planet formation calculations, it is usual to treat the initial properties of the planet forming disc (mass, radius, etc.) as free parameters. In this paper, we stress the importance of setting the formation of planet forming discs within the context of the formation of the central stars. By exploring the early stages of disc formation, we introduce the concept of the Maximum Mass Solar Nebula (MMSN), as opposed to the oft-used Minimum Mass Solar Nebula (here mmsn). It is evident that almost all protoplanetary discs start their evolution in a strongly self-gravitating state. In agreement with almost all previous work in this area, we conclude that on the scales relevant to planet formation these discs are not gravitationally unstable to gas fragmentation, but instead form strong, transient spiral arms. These spiral arms can act as efficient dust traps allowing the accumulation and subsequent fragmentation of the dust (but not the gas). This phase is likely to populate the disc with relatively large planetesimals on short timescales while the disc is still veiled by a dusty-gas envelope. Crucially, the early formation of large planetesimals overcomes the main barriers remaining within the core accretion model. A prediction of this picture is that essentially all observable protoplanetary discs are already planet hosting.

  13. Artificial Neural Network Maximum Power Point Tracker for Solar Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    Theodore Amissah OCRAN; CAO Junyi; CAO Binggang; SUN Xinghua

    2005-01-01

    This paper proposes an artificial neural network maximum power point tracker (MPPT) for solar electric vehicles. The MPPT is based on a highly efficient boost converter with insulated gate bipolar transistor (IGBT) power switch. The reference voltage for MPPT is obtained by artificial neural network (ANN) with gradient descent momentum algorithm. The tracking algorithm changes the duty-cycle of the converter so that the PV-module voltage equals the voltage corresponding to the MPPT at any given insolation, temperature, and load conditions. For fast response, the system is implemented using digital signal processor (DSP). The overall system stability is improved by including a proportional-integral-derivative (PID) controller, which is also used to match the reference and battery voltage levels. The controller, based on the information supplied by the ANN, generates the boost converter duty-cycle. The energy obtained is used to charge the lithium ion battery stack for the solar vehicle. The experimental and simulation results show that the proposed scheme is highly efficient.

  14. Duty-based control of maximum power point regulation for power converter in solar fan system with battery storage

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, J.-L.; Hong, P.-J. [National Kaohsiung First Univ. of Science and Technology, Nantze, Kaohsiung, Taiwan (China). Dept. of Mechanical and Automation Engineering; Chao, K.-L. [National Kaohsiung Univ. of Applied Sciences, Nantze, Kaohsiung, Taiwan (China). Dept. of Electrical Engineering; Wang, T.-Y. [Chang-Gung Univ., Kwei-Shan, Tao-Yuan, Taiwan (China). Dept. of Electrical Engineering

    2007-07-01

    Solar energy is a popular renewable energy source for the future because it does not produce any pollution. In addition, it is unlimited and a clean source of energy. This paper discussed a photovoltaic solar fan system that could be used inside the house with the potential of cooling the indoor temperature. The solar cell module is located at the eaves of the house and could block the sunlight directly into the house, and convert solar power into electric power through the battery. The paper described software implementation and hardware circuit design in detail. The paper also illustrated a different algorithm to calculate the maximum power point regulation. The conventional algorithm calculates the solar cell module output power by multiplying the input voltage and input current for the solar cell module directly. By changing the input voltage variable into duty variable, the voltage sensor is not required under the proposed scheme. Only the duty and current variables are needed to calculate the maximum power. The microchip dsPIC microcontroller was used to implement the algorithm. Different DC link levels were verified and implemented for comparison. It was concluded that the characteristics of the solar cell module could be measured automatically, and the maximum power point could be guaranteed by the proposed algorithm. 9 refs., 6 tabs., 14 figs.

  15. Solar wind fluctuations at large scale: A comparison between low and high solar activity conditions

    International Nuclear Information System (INIS)

    Bavassano, B.; Bruno, R.

    1991-01-01

    The influence of the Sun's activity cycle on the solar wind fluctuations at time scales from 1 hour to 3 days in the inner heliosphere (0.3 to 1 AU) is investigated. Hourly averages of plasma and magnetic field data by Helios spacecraft are used. Since fluctuations behave quite differently with changing scale, the analysis is performed separately for two different ranges in time scale. Between 1 and 6 hours Alfvenic fluctuations and pressure-balanced structures are extensively observed. At low solar activity and close to 0.3 AU, Alfvenic fluctuations are more frequent than pressure-balanced structures. This predominance, however, weakens for rising solar activity and radial distance, to the point that a role exchange, in terms of occurrence rate, is found at the maximum of the cycle close to 1 AU. On the other hand, in all cases Alfvenic fluctuations have a larger amplitude than pressure-balanced structures. On the whole, the Alfvenic contribution to the solar wind energy spectrum comes out to be dominant at all solar activity conditions. At scales from 0.5 to 3 days the most important feature is the growth, as the solar wind expansion develops, of strong positive correlations between magnetic and thermal pressures. These structures are progressively built up by the interaction between different wind flows. This effect is more pronounced at low than at high activity. Our findings support the conclusion that the solar cycle evolution of the large-scale velocity pattern is the factor governing the observed variations

  16. Deciphering Solar Magnetic Activity: Spotting Solar Cycle 25

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Scott W. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Leamon, Robert J., E-mail: mscott@ucar.edu [Department of Astronomy, University of Maryland, College Park, MD (United States)

    2017-06-26

    We present observational signatures of solar cycle 25 onset. Those signatures are visibly following a migratory path from high to low latitudes. They had starting points that are asymmetrically offset in each hemisphere at times that are 21–22 years after the corresponding, same polarity, activity bands of solar cycle 23 started their migration. Those bands define the so-called “extended solar cycle.” The four magnetic bands currently present in the system are approaching a mutually cancelling configuration, and solar minimum conditions are imminent. Further, using a tuned analysis of the daily band latitude-time diagnostics, we are able to utilize the longitudinal wave number (m = 1) variation in the data to more clearly reveal the presence of the solar cycle 25 bands. This clarification illustrates that prevalently active longitudes (different in each hemisphere) exist at mid-latitudes presently, lasting many solar rotations, that can be used for detailed study over the next several years with instruments like the Spectrograph on IRIS, the Spectropolarimeter on Hinode, and, when they come online, similar instruments on the Daniel K. Inouye Solar Telescope (DKIST) as we watch those bands evolve following the cancellation of the solar cycle 24 activity bands at the equator late in 2019.

  17. Fast-PPP assessment in European and equatorial region near the solar cycle maximum

    Science.gov (United States)

    Rovira-Garcia, Adria; Juan, José Miguel; Sanz, Jaume

    2014-05-01

    The Fast Precise Point Positioning (Fast-PPP) is a technique to provide quick high-accuracy navigation with ambiguity fixing capability, thanks to an accurate modelling of the ionosphere. Indeed, once the availability of real-time precise satellite orbits and clocks is granted to users, the next challenge is the accuracy of real-time ionospheric corrections. Several steps had been taken by gAGE/UPC to develop such global system for precise navigation. First Wide-Area Real-Time Kinematics (WARTK) feasibility studies enabled precise relative continental navigation using a few tens of reference stations. Later multi-frequency and multi-constellation assessments in different ionospheric scenarios, including maximum solar-cycle conditions, were focussed on user-domain performance. Recently, a mature evolution of the technique consists on a dual service scheme; a global Precise Point Positioning (PPP) service, together with a continental enhancement to shorten convergence. A end to end performance assessment of the Fast-PPP technique is presented in this work, focussed in Europe and in the equatorial region of South East Asia (SEA), both near the solar cycle maximum. The accuracy of the Central Processing Facility (CPF) real-time precise satellite orbits and clocks is respectively, 4 centimetres and 0.2 nanoseconds, in line with the accuracy of the International GNSS Service (IGS) analysis centres. This global PPP service is enhanced by the Fast-PPP by adding the capability of global undifferenced ambiguity fixing thanks to the fractional part of the ambiguities determination. The core of the Fast-PPP is the capability to compute real-time ionospheric determinations with accuracies at the level or better than 1 Total Electron Content Unit (TECU), improving the widely-accepted Global Ionospheric Maps (GIM), with declared accuracies of 2-8 TECU. This large improvement in the modelling accuracy is achieved thanks to a two-layer description of the ionosphere combined with

  18. Study of GNSS Loss of Lock Characteristics under Ionosphere Scintillation with GNSS Data at Weipa (Australia) During Solar Maximum Phase.

    Science.gov (United States)

    Liu, Yang; Fu, Lianjie; Wang, Jinling; Zhang, Chunxi

    2017-09-25

    One of the adverse impacts of scintillation on GNSS signals is the loss of lock status, which can lead to GNSS geometry and visibility reductions that compromise the accuracy and integrity of navigation performance. In this paper the loss of lock based on ionosphere scintillation in this solar maximum phase has been well investigated with respect to both temporal and spatial behaviors, based on GNSS observatory data collected at Weipa (Australia; geographic: 12.45° S, 130.95° E; geomagnetic: 21.79° S, 214.41° E) from 2011 to 2015. Experiments demonstrate that the percentage of occurrence of loss of lock events under ionosphere scintillation is closely related with solar activity and seasonal shifts. Loss of lock behaviors under ionosphere scintillation related to elevation and azimuth angles are statistically analyzed, with some distinct characteristics found. The influences of daytime scintillation and geomagnetic storms on loss of lock have also been discussed in details. The proposed work is valuable for a deeper understanding of theoretical mechanisms of-loss of lock under ionosphere scintillation in global regions, and provides a reference for GNSS applications in certain regions at Australian low latitudes.

  19. Multiwavelength analysis of a well observed flare from SMM. [Solar Maximum Mission

    Science.gov (United States)

    Macneice, P.; Pallavicini, R.; Mason, H. E.; Simnett, G. M.; Antonucci, E.; Shine, R. A.; Dennis, B. R.

    1985-01-01

    Observations of an M 1.4 flare which began at 17:00 UT on November 12, 1980, are presented and analyzed. Ground based H-alpha and magnetogram data have been combined with EUV, soft and hard X-ray observations made with instruments on-board the Solar Maximum Mission satellite. The preflare phase was marked by a gradual brightening of the flare site in O v and the disappearance of an H-alpha filament. Filament ejecta were seen in O v moving southward at a speed of about 60 km/s, before the impulsive phase. The flare loop footpoints brightened in H-alpha and the Ca XIX resonance line broadened dramatically 2 min before the impulsive phase. Nonthermal hard X-ray emission was detected from the loop footpoints during the impulsive phase, while during the same period blue-shifts corresponding to upflows of 200-250 km/s were seen in Ca XIX. Evidence was found for energy deposition in both the chromosphere and corona at a number of stages during the flare. Two widely studied mechanisms for the production of the high temperature soft X-ray flare plasma in the corona are considered, i.e. chromospheric evaporation, and a model in which the heating and transfer of material occurs between flux tubes during reconnection.

  20. Fixed-head star tracker magnitude calibration on the solar maximum mission

    Science.gov (United States)

    Pitone, Daniel S.; Twambly, B. J.; Eudell, A. H.; Roberts, D. A.

    1990-01-01

    The sensitivity of the fixed-head star trackers (FHSTs) on the Solar Maximum Mission (SMM) is defined as the accuracy of the electronic response to the magnitude of a star in the sensor field-of-view, which is measured as intensity in volts. To identify stars during attitude determination and control processes, a transformation equation is required to convert from star intensity in volts to units of magnitude and vice versa. To maintain high accuracy standards, this transformation is calibrated frequently. A sensitivity index is defined as the observed intensity in volts divided by the predicted intensity in volts; thus, the sensitivity index is a measure of the accuracy of the calibration. Using the sensitivity index, analysis is presented that compares the strengths and weaknesses of two possible transformation equations. The effect on the transformation equations of variables, such as position in the sensor field-of-view, star color, and star magnitude, is investigated. In addition, results are given that evaluate the aging process of each sensor. The results in this work can be used by future missions as an aid to employing data from star cameras as effectively as possible.

  1. Neutron spectrum and dose-equivalent in shuttle flights during solar maximum

    Energy Technology Data Exchange (ETDEWEB)

    Keith, J E; Badhwar, G D; Lindstrom, D J [National Aeronautics and Space Administration, Houston, TX (United States). Lyndon B. Johnson Space Center

    1992-01-01

    This paper presents unambiguous measurements of the spectrum of neutrons found in spacecraft during spaceflight. The neutron spectrum was measured from thermal energies to about 10 MeV using a completely passive system of metal foils as neutron detectors. These foils were exposed to the neutron flux bare, covered by thermal neutron absorbers (Gd) and inside moderators (Bonner spheres). This set of detectors was flown on three U.S. Space Shuttle flights, STS-28, STS-36 and STS-31, during the solar maximum. We show that the measurements of the radioactivity of these foils lead to a differential neutron energy spectrum in all three flights that can be represented by a power law, J(E){approx equal}E{sup -0.765} neutrons cm{sup -2} day {sup -1} MeV{sup -1}. We also show that the measurements are even better represented by a linear combination of the terrestrial neutron albedo and a spectrum of neutrons locally produced in a aluminium by protons, computed by a previous author. We use both approximations to the neutron spectrum to produce a worst case and most probable case for the neutron spectra and the resulting dose-equivalents, computed using ICRP-51 neutron fluence-dose conversion tables. We compare these to the skin dose-equivalents due to charged particles during the same flights. (author).

  2. Dual-Axis Solar Tracking System for Maximum Power Production in ...

    African Journals Online (AJOL)

    Akorede

    ABSTRACT: The power developed in a solar energy system depends fundamentally upon the ... for power generation. ... determined because they are functions of the solar angles that ..... able to withstand the weight and the blowing wind.

  3. Properties and geoeffectiveness of magnetic clouds in the rising, maximum and early declining phases of solar cycle 23

    Directory of Open Access Journals (Sweden)

    K. E. J. Huttunen

    2005-02-01

    Full Text Available The magnetic structure and geomagnetic response of 73 magnetic clouds (MC observed by the WIND and ACE satellites in solar cycle 23 are examined. The results have been compared with the surveys from the previous solar cycles. The preselected candidate MC events were investigated using the minimum variance analysis to determine if they have a flux-rope structure and to obtain the estimation for the axial orientation (θC, φC. Depending on the calculated inclination relative to the ecliptic we divided MCs into "bipolar" (θC<45° and "unipolar" (θC>45°. The number of observed MCs was largest in the early rising phase, although the halo CME rate was still low. It is likely that near solar maximum we did not identify all MCs at 1AU, as they were crossed far from the axis or they had interacted strongly with the ambient solar wind or with other CMEs. The occurrence rate of MCs at 1AU is also modified by the migration of the filament sites on the Sun towards the poles near solar maximum and by the deflection of CMEs towards the equator due to the fast solar wind flow from large polar coronal holes near solar minimum. In the rising phase nearly all bipolar MCs were associated with the rotation of the magnetic field from the south at the leading edge to the north at the trailing edge. The results for solar cycles 21-22 showed that the direction of the magnetic field in the leading portion of the MC starts to reverse at solar maximum. At solar maximum and in the declining phase (2000-2003 we observed several MCs with the rotation from the north to the south. We observed unipolar (i.e. highly inclined MCs frequently during the whole investigated period. For solar cycles 21-22 the majority of MCs identified in the rising phase were bipolar while in the declining phase most MCs were unipolar. The geomagnetic response of a given MC depends greatly on its magnetic structure and the orientation of the sheath fields. For each event we distinguished the

  4. Sustainable Buildings. Using Active Solar Power

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, M. Keith [Univ. of Louisville, KY (United States); Barnett, Russell [Univ. of Louisville, KY (United States)

    2015-04-20

    The objective of this project is to promote awareness and knowledge of active solar energy technologies by installing and monitoring the following demonstration systems in Kentucky: 1) Pool heating system, Churchill Park School, 2) Water heating and daylighting systems, Middletown and Aiken Road Elementary Schools, 3) Photovoltaic street light comparison, Louisville Metro, 4) up to 25 domestic water heating systems across Kentucky. These tasks will be supported by outreach activities, including a solar energy installer training workshop and a Kentucky Solar Energy Conference.

  5. A new perspective on solar active regions

    Science.gov (United States)

    Strong, K. T.; Bruner, M. E.

    1996-01-01

    A flood of new observations of the solar corona have been made with high spatial resolution, good temporal coverage and resolution, and large linear dynamic range by the Soft X-ray Telescope (SXT) on Yohkoh. These data are changing our fundamental understanding of how solar magnetic fields emerge, interact, and dissipate. This paper reviews some of the results from Yohkoh in the context of earlier results from the Solar Maximum Mission (SMM) and in comjunction with ground-based optical and radio observations.

  6. Design and implementation of a microcontroller-based maximum power point tracking fuzzy solar-charge controller

    Energy Technology Data Exchange (ETDEWEB)

    Qazalbash, A.A.; Iqbal, T.; Shafiq, M.Z. [National Univ. of Sciences and Technology, Rawalpindi (Pakistan). Dept. of Electrical Engineering

    2007-07-01

    Photovoltaic (PV) solar arrays are particularly useful for electrical power generation in remote, off-grid areas in developing countries. However, PV arrays offer a small power to area ratio, resulting in the need for more PV arrays which increases the cost of the system. In order to improve the profitability of PV arrays, the power extraction from available PV array systems must be maximized. This paper presented an analysis, modeling and implementation of an efficient solar charge controller. It was shown that the maximum power of a photovoltaic system depends largely on temperature and insolation. A perturb and observe algorithm was used for maximum power point tracking (MPPT). MPPT maximizes the efficiency of a solar PV system. A solar charge controller determines the optimal values of output current and voltage of converters to maximize power output for battery charging. In order to improve performance and implement the perturb and observe algorithm, the authors designed a fuzzy rule-based system in which a solar charge controller worked with a PWM controlled DC-DC converter for battery charging. The system was implemented on a low-cost PIC microcontroller. Results were better than conventional techniques in power efficiency. Swift maximum power point tracking was obtained. 13 refs., 1 tab., 11 figs.

  7. Solar wind fluctuations at large scale - A comparison between low and high solar activity conditions

    Science.gov (United States)

    Bavassano, B.; Bruno, R.

    1991-02-01

    The influence of the sun's activity cycle on the solar wind fluctuations at time scales from 1 hour to 3 days in the inner heliosphere (0.3 to 1 AU) is investigated. Hourly averages of plasma and magnetic field data by Helios spacecraft are used. Since fluctuations behave quite differently with changing scale, the analysis is performed separately for two different ranges in time scale. Between 1 and 6 hours Alfvenic fluctuations and pressure-balanced structures are extensively observed. At low solar activity and close to 0.3 AU Alfvenic fluctuations are more frequent than pressure-balanced structures. This predominance, however, weakens for rising solar activity and radial distance, to the point that a role-exchange, in terms of occurrence rate, is found at the maximum of the cycle close to 1 AU. On the other hand, in all cases Alfvenic fluctuations have a larger amplitude than pressure-balanced structures. The Alfvenic contribution to the solar wind energy spectrum comes out to be dominant at all solar activity conditions. These findings support the conclusion that the solar cycle evolution of the large-scale velocity pattern is the factor governing the observed variations.

  8. Solar Spots - Activities to Introduce Solar Energy into the K-8 Curricula.

    Science.gov (United States)

    Longe, Karen M.; McClelland, Michael J.

    Following an introduction to solar technology which reviews solar heating and cooling, passive solar systems (direct gain systems, thermal storage walls, sun spaces, roof ponds, and convection loops), active solar systems, solar electricity (photovoltaic and solar thermal conversion systems), wind energy, and biomass, activities to introduce solar…

  9. Activity associated with the solar origin of coronal mass ejections

    Science.gov (United States)

    Webb, D. F.; Hundhausen, A. J.

    1987-01-01

    Solar coronal mass ejections (CMEs) observed in 1980 with the HAO Coronagraph/Polarimeter on the Solar Maximum Mission (SMM) satellite are compared with other forms of solar activity that might be physically related to the ejections. The solar phenomena checked and the method of association used were intentionally patterned after those of Munro et al.'s (1979) analysis of mass ejections observed with the Skylab coronagraph to facilitate comparison of the two epochs. Comparison of the results reveals that the types and degree of CME associations are similar near solar activity minimum and at maximum. For both epochs, most CMEs with associations had associated eruptive prominences, and the proportions of association of all types of activity were similar. A high percentage of association between SMM CMEs and X-ray long duration events is also found, in agreement with Skylab results. It is concluded that most CMEs are the result of the destabilization and eruption of a prominence and its overlying coronal structure, or of a magnetic structure capable of supporting a prominence.

  10. Predicting the start and maximum amplitude of solar cycle 24 using similar phases and a cycle grouping

    International Nuclear Information System (INIS)

    Wang Jialong; Zong Weiguo; Le Guiming; Zhao Haijuan; Tang Yunqiu; Zhang Yang

    2009-01-01

    We find that the solar cycles 9, 11, and 20 are similar to cycle 23 in their respective descending phases. Using this similarity and the observed data of smoothed monthly mean sunspot numbers (SMSNs) available for the descending phase of cycle 23, we make a date calibration for the average time sequence made of the three descending phases of the three cycles, and predict the start of March or April 2008 for cycle 24. For the three cycles, we also find a linear correlation of the length of the descending phase of a cycle with the difference between the maximum epoch of this cycle and that of its next cycle. Using this relationship along with the known relationship between the rise-time and the maximum amplitude of a slowly rising solar cycle, we predict the maximum SMSN of cycle 24 of 100.2 ± 7.5 to appear during the period from May to October 2012. (letters)

  11. Statistical Properties of Geomagnetic Activity Indices and Solar Wind Parameters

    Directory of Open Access Journals (Sweden)

    Jung-Hee Kim

    2014-06-01

    Full Text Available As the prediction of geomagnetic storms is becoming an important and practical problem, conditions in the Earth’s magnetosphere have been studied rigorously in terms of those in the interplanetary space. Another approach to space weather forecast is to deal with it as a probabilistic geomagnetic storm forecasting problem. In this study, we carry out detailed statistical analysis of solar wind parameters and geomagnetic indices examining the dependence of the distribution on the solar cycle and annual variations. Our main findings are as follows: (1 The distribution of parameters obtained via the superimposed epoch method follows the Gaussian distribution. (2 When solar activity is at its maximum the mean value of the distribution is shifted to the direction indicating the intense environment. Furthermore, the width of the distribution becomes wider at its maximum than at its minimum so that more extreme case can be expected. (3 The distribution of some certain heliospheric parameters is less sensitive to the phase of the solar cycle and annual variations. (4 The distribution of the eastward component of the interplanetary electric field BV and the solar wind driving function BV2, however, appears to be all dependent on the solar maximum/minimum, the descending/ascending phases of the solar cycle and the equinoxes/solstices. (5 The distribution of the AE index and the Dst index shares statistical features closely with BV and BV2 compared with other heliospheric parameters. In this sense, BV and BV2 are more robust proxies of the geomagnetic storm. We conclude by pointing out that our results allow us to step forward in providing the occurrence probability of geomagnetic storms for space weather and physical modeling.

  12. Forecasting the peak of the present solar activity cycle 24

    Science.gov (United States)

    Hamid, R. H.; Marzouk, B. A.

    2018-06-01

    Solar forecasting of the level of sun Activity is very important subject for all space programs. Most predictions are based on the physical conditions prevailing at or before the solar cycle minimum preceding the maximum in question. Our aim is to predict the maximum peak of cycle 24 using precursor techniques in particular those using spotless event, geomagnetic aamin. index and solar flux F10.7. Also prediction of exact date of the maximum (Tr) is taken in consideration. A study of variation over previous spotless event for cycles 7-23 and that for even cycles (8-22) are carried out for the prediction. Linear correlation between maximum of solar cycles (RM) and spotless event around the preceding minimum gives R24t = 88.4 with rise time Tr = 4.6 years. For the even cycles R24E = 77.9 with rise time Tr = 4.5 y's. Based on the average aamin. index for cycles (12-23), we estimate the expected amplitude for cycle 24 to be Raamin = 99.4 and 98.1 with time rise of Traamin = 4.04 & 4.3 years for both the total and even cycles in consecutive. The application of the data of solar flux F10.7 which cover only cycles (19-23) was taken in consideration and gives predicted maximum amplitude R24 10.7 = 126 with rise time Tr107 = 3.7 years, which are over estimation. Our result indicating to somewhat weaker of cycle 24 as compared to cycles 21-23.

  13. Design and simulation of maximum power point tracking (MPPT) system on solar module system using constant voltage (CV) method

    Science.gov (United States)

    Bhatara, Sevty Satria; Iskandar, Reza Fauzi; Kirom, M. Ramdlan

    2016-02-01

    Solar energy is one of renewable energy resource where needs a photovoltaic module to convert it into electrical energy. One of the problems on solar energy conversion is the process of battery charging. To improve efficiency of energy conversion, PV system needs another control method on battery charging called maximum power point tracking (MPPT). This paper report the study on charging optimation using constant voltage (CV) method. This method has a function of determining output voltage of the PV system on maximal condition, so PV system will always produce a maximal energy. A model represented a PV system with and without MPPT was developed using Simulink. PV system simulation showed a different outcome energy when different solar radiation and numbers of solar module were applied in the model. On the simulation of solar radiation 1000 W/m2, PV system with MPPT produces 252.66 Watt energy and PV system without MPPT produces 252.66 Watt energy. The larger the solar radiation, the greater the energy of PV modules was produced.

  14. Identification of PV solar cells and modules parameters using the genetic algorithms: Application to maximum power extraction

    Energy Technology Data Exchange (ETDEWEB)

    Zagrouba, M.; Sellami, A.; Bouaicha, M. [Laboratoire de Photovoltaique, des Semi-conducteurs et des Nanostructures, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, Tunis, B.P. 95, 2050 Hammam-Lif (Tunisia); Ksouri, M. [Unite de Recherche RME-Groupe AIA, Institut National des Sciences Appliquees et de Technologie (Tunisia)

    2010-05-15

    In this paper, we propose to perform a numerical technique based on genetic algorithms (GAs) to identify the electrical parameters (I{sub s}, I{sub ph}, R{sub s}, R{sub sh}, and n) of photovoltaic (PV) solar cells and modules. These parameters were used to determine the corresponding maximum power point (MPP) from the illuminated current-voltage (I-V) characteristic. The one diode type approach is used to model the AM1.5 I-V characteristic of the solar cell. To extract electrical parameters, the approach is formulated as a non convex optimization problem. The GAs approach was used as a numerical technique in order to overcome problems involved in the local minima in the case of non convex optimization criteria. Compared to other methods, we find that the GAs is a very efficient technique to estimate the electrical parameters of PV solar cells and modules. Indeed, the race of the algorithm stopped after five generations in the case of PV solar cells and seven generations in the case of PV modules. The identified parameters are then used to extract the maximum power working points for both cell and module. (author)

  15. Statistical Analysis of Solar Events Associated with Storm Sudden Commencements over One Year of Solar Maximum During Cycle 23: Propagation from the Sun to the Earth and Effects

    Science.gov (United States)

    Bocchialini, K.; Grison, B.; Menvielle, M.; Chambodut, A.; Cornilleau-Wehrlin, N.; Fontaine, D.; Marchaudon, A.; Pick, M.; Pitout, F.; Schmieder, B.; Régnier, S.; Zouganelis, I.

    2018-05-01

    Taking the 32 storm sudden commencements (SSCs) listed by the International Service of Geomagnetic Indices (ISGI) of the Observatory de l'Ebre during 2002 (solar activity maximum in Cycle 23) as a starting point, we performed a multi-criterion analysis based on observations (propagation time, velocity comparisons, sense of the magnetic field rotation, radio waves) to associate them with solar sources, identified their effects in the interplanetary medium, and looked at the response of the terrestrial ionized and neutral environment. We find that 28 SSCs can be related to 44 coronal mass ejections (CMEs), 15 with a unique CME and 13 with a series of multiple CMEs, among which 19 (68%) involved halo CMEs. Twelve of the 19 fastest CMEs with speeds greater than 1000 km s-1 are halo CMEs. For the 44 CMEs, including 21 halo CMEs, the corresponding X-ray flare classes are: 3 X-class, 19 M-class, and 22 C-class flares. The probability for an SSC to occur is 75% if the CME is a halo CME. Among the 500, or even more, front-side, non-halo CMEs recorded in 2002, only 23 could be the source of an SSC, i.e. 5%. The complex interactions between two (or more) CMEs and the modification of their trajectories have been examined using joint white-light and multiple-wavelength radio observations. The detection of long-lasting type IV bursts observed at metric-hectometric wavelengths is a very useful criterion for the CME-SSC events association. The events associated with the most depressed Dst values are also associated with type IV radio bursts. The four SSCs associated with a single shock at L1 correspond to four radio events exhibiting characteristics different from type IV radio bursts. The solar-wind structures at L1 after the 32 SSCs are 12 magnetic clouds (MCs), 6 interplanetary coronal mass ejections (ICMEs) without an MC structure, 4 miscellaneous structures, which cannot unambiguously be classified as ICMEs, 5 corotating or stream interaction regions (CIRs/SIRs), one CIR

  16. Ten cycles of solar and geomagnetic activity

    International Nuclear Information System (INIS)

    Legrand, J.P.

    1981-01-01

    Series of 110 years of sunspot numbers and indices of geomagnetic activity are used with 17 years of solar wind data in order to study through solar cycles both stream and shock event solar activity. According to their patterns on Bartels diagrams of geomagnetic indices, stable wind streams and transient solar activities are separated from each other. Two classes of stable streams are identified: equatorial streams occurring sporadically, for several months, during the main phase of sunspot cycles and both polar streams established, for several years, at each cycle, before sunspot minimum. Polar streams are the first activity of solar cycles. For study of the relationship between transient geomagnetic phenomena and sunspot activity, we raise the importance of the contribution, at high spot number, of severe storms and, at low spot number, of short lived and unstable streams. Solar wind data are used to check and complete the above results. As a conclusion, we suggest a unified scheme of solar activity evolution with a starting point every eleventh year, a total duration of 17 years and an overlapping of 6 years between the first and the last phase of both successive series of phenomena: first, from polar field reversal to sunspot minimum, a phase of polar wind activity of the beginning cycle is superimposed on the weak contribution of shock events of the ending cycle; secondly, an equatorial phase mostly of shock events is superimposed on a variable contribution of short lived and sporadic stable equatorial stream activities; and thirdly a phase of low latitude shock events is superimposed on the polar stream interval of the following cycle. (orig.)

  17. Design, fabrication and performance of a hybrid photovoltaic/thermal (PV/T) active solar still

    International Nuclear Information System (INIS)

    Kumar, Shiv; Tiwari, Arvind

    2010-01-01

    Two solar stills (single slope passive and single slope photovoltaic/thermal (PV/T) active solar still) were fabricated and tested at solar energy park, IIT New Delhi (India) for composite climate. Photovoltaic operated DC water pump was used between solar still and photovoltaic (PV) integrated flat plate collector to re-circulate the water through the collectors and transfer it to the solar still. The newly designed hybrid (PV/T) active solar still is self-sustainable and can be used in remote areas, need to transport distilled water from a distance and not connected to grid, but blessed with ample solar energy. Experiments were performed for 0.05, 0.10, and 0.15 m water depth, round the year 2006-2007 for both the stills. It has been observed that maximum daily yield of 2.26 kg and 7.22 kg were obtained from passive and hybrid active solar still, respectively at 0.05 m water depth. The daily yield from hybrid active solar still is around 3.2 and 5.5 times higher than the passive solar still in summer and winter month, respectively. The study has shown that this design of the hybrid active solar still also provides higher electrical and overall thermal efficiency, which is about 20% higher than the passive solar still.

  18. Prediciting Solar Activity: Today, Tomorrow, Next Year

    Science.gov (United States)

    Pesnell, William Dean

    2008-01-01

    Fleets of satellites circle the Earth collecting science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to space weather effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less fuel can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory. Energetic events at the Sun can produce crippling radiation storms. Predicting those events that will affect our assets in space includes a solar prediction and how the radiation will propagate through the solar system. I will talk our need for solar activity predictions and anticipate how those predictions could be made more accurate in the future.

  19. Signature of a possible relationship between the maximum CME speed index and the critical frequencies of the F1 and F2 ionospheric layers: Data analysis for a mid-latitude ionospheric station during the solar cycles 23 and 24

    Science.gov (United States)

    Kilcik, Ali; Ozguc, Atila; Yiǧit, Erdal; Yurchyshyn, Vasyl; Donmez, Burcin

    2018-06-01

    We analyze temporal variations of two solar indices, the monthly mean Maximum CME Speed Index (MCMESI) and the International Sunspot Number (ISSN) as well as the monthly median ionospheric critical frequencies (foF1, and foF2) for the time period of 1996-2013, which covers the entire solar cycle 23 and the ascending branch of the cycle 24. We found that the maximum of foF1 and foF2 occurred respectively during the first and second maximum of the ISSN solar activity index in the solar cycle 23. We compared these data sets by using the cross-correlation and hysteresis analysis and found that both foF1 and foF2 show higher correlation with ISSN than the MCMESI during the investigated time period, but when significance levels are considered correlation coefficients between the same indices become comparable. Cross-correlation analysis showed that the agreement between these data sets (solar indices and ionospheric critical frequencies) is better pronounced during the ascending phases of solar cycles, while they display significant deviations during the descending phase. We conclude that there exists a signature of a possible relationship between MCMESI and foF1 and foF2, which means that MCMESI could be used as a possible indicator of solar and geomagnetic activity, even though other investigations are needed.

  20. Active solar distillation - A detailed review

    Energy Technology Data Exchange (ETDEWEB)

    Sampathkumar, K.; Pitchandi, P. [Department of Mechanical Engineering, Tamilnadu College of Engineering, Coimbatore 641659, Tamilnadu (India); Arjunan, T.V. [Department of Automobile Engineering, PSG College of Technology, Coimbatore 641004, Tamilnadu (India); Senthilkumar, P. [Department of Mechanical Engineering, KSR College of Engineering, Tiruchengode 637215, Tamilnadu (India)

    2010-08-15

    All over the world, access to potable water to the people are narrowing down day by day. Most of the human diseases are due to polluted or non-purified water resources. Even today, under developed countries and developing countries face a huge water scarcity because of unplanned mechanism and pollution created by manmade activities. Water purification without affecting the ecosystem is the need of the hour. In this context, many conventional and non-conventional techniques have been developed for purification of saline water. Among these, solar distillation proves to be both economical and eco-friendly technique particularly in rural areas. Many active distillation systems have been developed to overcome the problem of lower distillate output in passive solar stills. This article provides a detailed review of different studies on active solar distillation system over the years. Thermal modelling was done for various types of active single slope solar distillation system. This review would also throw light on the scope for further research and recommendations in active solar distillation system. (author)

  1. Dual-Axis Solar Tracking System for Maximum Power Production in PV Systems

    Directory of Open Access Journals (Sweden)

    Muhd.Ikram Mohd. Rashid

    2015-12-01

    Full Text Available The power developed in a solar energy system depends fundamentally upon the amount of sunlight captured by the photovoltaic modules/arrays. This paper describes a simple electro-mechanical dual axis solar tracking system designed and developed in a study. The control of the two axes was achieved by the pulses generated from the data acquisition (DAQ card fed into four relays. This approach was so chosen to effectively avoid the error that usually arises in sensor-based methods. The programming of the mathematical models of the solar elevation and azimuth angles was done using Borland C++ Builder. The performance and accuracy of the developed system was evaluated with a PV panel at latitude 3.53o N and longitude 103.5o W in Malaysia. The results obtained reflect the effectiveness of the developed tracking system in terms of the energy yield when compared with that generated from a fixed panel. Overall, 20%, 23% and 21% additional energy were produced for the months of March, April and May respectively using the tracker developed in this study.

  2. Impulsive and gradual phases of a solar limb flare as observed from the solar maximum mission satellite

    Energy Technology Data Exchange (ETDEWEB)

    Poland, A.I.; Frost, K.J.; Woodgate, B.E.; Shine, R.A.; Kenny, P.J. (National Aeronautics and Space Administration, Greenbelt, MD (USA). Lab. for Astronomy and Solar Physics); Machado, M.E. (Observatorio Nacional de Fisica Cosmica, San Miguel (Argentina)); Wolfson, C.J.; Bruner, E.C. (Lockheed Palo Alto Research Labs., CA (USA)); Cheng, C.C. (Naval Research Lab., Washington, DC (USA)); Tandberg-Hanssen, E.A. (National Aeronautics and Space Administration, Huntsville, AL (USA). George C. Marshall Space Flight Center)

    1982-06-01

    Simultaneous observations of a solar limb flare in the X-ray and ultraviolet regions of the spectrum are presented. Temporal and spectral X-ray observations were obtained for the 25-300 keV range while temporal, spectral, and spatial X-ray observations were obtained for the 30-0.3 keV range. The ultraviolet observations were images with a 10'' spatial resolution in the lines of O v (Tsub(e) approx. equal to 2.5 x 10/sup 5/ K) and Fe XXI (Tsub(e) approx. equal to 1.1 x 10/sup 7/ K). The hard X-ray and O v data indicate that the impulsive phase began in the photosphere or chromosphere and continued for several minutes as material was ejected into the corona. Impulsive excitation was observed up to 30,000 km above the solar surface at specific points in the flare loop. The Fe XXI observations indicate a preheating before the impulsive phase and showed the formation of hot post-flare loops. This later formation was confirmed by soft X-ray observations. These observations provide limitations for current flare models and will provide the data needed for initial conditions in modeling the concurrent coronal transient.

  3. The impulsive and gradual phases of a solar limb flare as observed from the solar maximum mission satellite

    International Nuclear Information System (INIS)

    Poland, A.I.; Frost, K.J.; Woodgate, B.E.; Shine, R.A.; Kenny, P.J.; Wolfson, C.J.; Bruner, E.C.; Cheng, C.C.; Tandberg-Hanssen, E.A.

    1982-01-01

    Simultaneous observations of a solar limb flare in the X-ray and ultraviolet regions of the spectrum are presented. Temporal and spectral X-ray observations were obtained for the 25-300 keV range while temporal, spectral, and spatial X-ray observations were obtained for the 30-0.3 keV range. The ultraviolet observations were images with a 10'' spatial resolution in the lines of O v (Tsub(e) approx. equal to 2.5 x 10 5 K) and Fe XXI (Tsub(e) approx. equal to 1.1 x 10 7 K). The hard X-ray and O v data indicate that the impulsive phase began in the photosphere or chromosphere and continued for several minutes as material was ejected into the corona. Impulsive excitation was observed up to 30,000 km above the solar surface at specific points in the flare loop. The Fe XXI observations indicate a preheating before the impulsive phase and showed the formation of hot post-flare loops. This later formation was confirmed by soft X-ray observations. These observations provide limitations for current flare models and will provide the data needed for initial conditions in modeling the concurrent coronal transient. (orig.)

  4. Solar Energy Education. Home economics: student activities. Field test edition

    Energy Technology Data Exchange (ETDEWEB)

    1981-03-01

    A view of solar energy from the standpoint of home economics is taken in this book of activities. Students are provided information on solar energy resources while performing these classroom activities. Instructions for the construction of a solar food dryer and a solar cooker are provided. Topics for study include window treatments, clothing, the history of solar energy, vitamins from the sun, and how to choose the correct solar home. (BCS)

  5. Migration and Extension of Solar Active Longitudinal Zones

    Science.gov (United States)

    Gyenge, N.; Baranyi, T.; Ludmány, A.

    2014-02-01

    Solar active longitudes show a characteristic migration pattern in the Carrington coordinate system if they can be identified at all. By following this migration, the longitudinal activity distribution around the center of the band can be determined. The half-width of the distribution is found to be varying in Cycles 21 - 23, and in some time intervals it was as narrow as 20 - 30 degrees. It was more extended around a maximum but it was also narrow when the activity jumped to the opposite longitude. Flux emergence exhibited a quasi-periodic variation within the active zone with a period of about 1.3 years. The path of the active-longitude migration does not support the view that it might be associated with the 11-year solar cycle. These results were obtained for a limited time interval of a few solar cycles and, bearing in mind uncertainties of the migration-path definition, are only indicative. For the major fraction of the dataset no systematic active longitudes were found. Sporadic migration of active longitudes was identified only for Cycles 21 - 22 in the northern hemisphere and Cycle 23 in the southern hemisphere.

  6. Improvement of maximum power point tracking perturb and observe algorithm for a standalone solar photovoltaic system

    International Nuclear Information System (INIS)

    Awan, M.M.A.; Awan, F.G.

    2017-01-01

    Extraction of maximum power from PV (Photovoltaic) cell is necessary to make the PV system efficient. Maximum power can be achieved by operating the system at MPP (Maximum Power Point) (taking the operating point of PV panel to MPP) and for this purpose MPPT (Maximum Power Point Trackers) are used. There are many tracking algorithms/methods used by these trackers which includes incremental conductance, constant voltage method, constant current method, short circuit current method, PAO (Perturb and Observe) method, and open circuit voltage method but PAO is the mostly used algorithm because it is simple and easy to implement. PAO algorithm has some drawbacks, one is low tracking speed under rapid changing weather conditions and second is oscillations of PV systems operating point around MPP. Little improvement is achieved in past papers regarding these issues. In this paper, a new method named 'Decrease and Fix' method is successfully introduced as improvement in PAO algorithm to overcome these issues of tracking speed and oscillations. Decrease and fix method is the first successful attempt with PAO algorithm for stability achievement and speeding up of tracking process in photovoltaic system. Complete standalone photovoltaic system's model with improved perturb and observe algorithm is simulated in MATLAB Simulink. (author)

  7. The maximum theoretical performance of unconcentrated solar photovoltaic and thermoelectric generator systems

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Nielsen, Kaspar Kirstein

    2017-01-01

    The maximum efficiency for photovoltaic (PV) and thermoelectric generator (TEG) systems without concentration is investigated. Both a combined system where the TEG is mounted directly on the back of the PV and a tandem system where the incoming sunlight is split, and the short wavelength radiation...

  8. Radar meteor rates and solar activity

    International Nuclear Information System (INIS)

    Prikryl, P.

    1983-01-01

    The short-term variation of diurnal radar meteor rates with solar activity represented by solar microwave flux Fsub(10.7), and sunspots relative number Rsub(z), is investigated. Applying the superposed-epoch analysis to the observational material of radar meteor rates from Christchurch (1960-61 and 1963-65), a decrease in the recorded radar rates is found during days of enhanced solar activity. No effect of geomagnetic activity similar to the one reported for the Swedish and Canadian radar meteor data was found by the author in the Christchurch data. A possible explanation of the absence of the geomagnetic effect on radar meteor rates from New Zealand due to a lower echo ceiling height of the Christchurch radar is suggested. The variation of the atmospheric parameters as a possible cause of the observed variation in radar meteor rates is also discussed. (author)

  9. Characteristics of seasonal variation and solar activity dependence of the geomagnetic solar quiet daily variation

    Science.gov (United States)

    Shinbori, A.; Koyama, Y.; Nose, M.; Hori, T.

    2017-12-01

    Characteristics of seasonal variation and solar activity dependence of the X- and Y-components of the geomagnetic solar quiet (Sq) daily variation at Memanbetsu in mid-latitudes and Guam near the equator have been investigated using long-term geomagnetic field data with 1-h time resolution from 1957 to 2016. In this analysis, we defined the quiet day when the maximum value of the Kp index is less than 3 for that day. In this analysis, we used the monthly average of the adjusted daily F10.7 corresponding to geomagnetically quiet days. For identification of the monthly mean Sq variation in the X and Y components (Sq-X and Sq-Y), we first determined the baseline of the X and Y components from the average value from 22 to 2 h (LT: local time) for each quiet day. Next, we calculated a deviation from the baseline of the X- and Y-components of the geomagnetic field for each quiet day, and computed the monthly mean value of the deviation for each local time. As a result, Sq-X and Sq-Y shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities, and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq-X and Sq-Y. The result of the correlation analysis between the solar F10.7 index and Sq-X and Sq-Y shows almost the linear relationship, but the slope and intercept of the linear fitted line varies as function of local time and month. This implies that the sensitivity of Sq-X and Sq-Y to the solar activity is different for different local times and seasons. The local time dependence of the offset value of Sq-Y at Guam and its seasonal variation suggest a magnetic field produced by inter-hemispheric field-aligned currents (FACs). From the sign of the offset value of Sq-Y, it is infer that the inter-hemispheric FACs flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in

  10. The Effect of "Rogue" Active Regions on the Solar Cycle

    Science.gov (United States)

    Nagy, Melinda; Lemerle, Alexandre; Labonville, François; Petrovay, Kristóf; Charbonneau, Paul

    2017-11-01

    The origin of cycle-to-cycle variations in solar activity is currently the focus of much interest. It has recently been pointed out that large individual active regions with atypical properties can have a significant impact on the long-term behavior of solar activity. We investigate this possibility in more detail using a recently developed 2×2D dynamo model of the solar magnetic cycle. We find that even a single "rogue" bipolar magnetic region (BMR) in the simulations can have a major effect on the further development of solar activity cycles, boosting or suppressing the amplitude of subsequent cycles. In extreme cases, an individual BMR can completely halt the dynamo, triggering a grand minimum. Rogue BMRs also have the potential to induce significant hemispheric asymmetries in the solar cycle. To study the effect of rogue BMRs in a more systematic manner, a series of dynamo simulations were conducted, in which a large test BMR was manually introduced in the model at various phases of cycles of different amplitudes. BMRs emerging in the rising phase of a cycle can modify the amplitude of the ongoing cycle, while BMRs emerging in later phases will only affect subsequent cycles. In this model, the strongest effect on the subsequent cycle occurs when the rogue BMR emerges around cycle maximum at low latitudes, but the BMR does not need to be strictly cross-equatorial. Active regions emerging as far as 20° from the equator can still have a significant effect. We demonstrate that the combined effect of the magnetic flux, tilt angle, and polarity separation of the BMR on the dynamo is via their contribution to the dipole moment, δ D_{BMR}. Our results indicate that prediction of the amplitude, starting epoch, and duration of a cycle requires an accurate accounting of a broad range of active regions emerging in the previous cycle.

  11. A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups

    Science.gov (United States)

    Ruždjak, Domagoj; Brajša, Roman; Sudar, Davor; Skokić, Ivica; Poljančić Beljan, Ivana

    2017-12-01

    The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differential-rotation parameters A and B. These differential-rotation parameters were compared with the solar-activity level. We found that the Sun rotates more differentially at the minimum than at the maximum of activity during the epoch 1977 - 2016. An inverse correlation between equatorial rotation and solar activity was found using the recently revised sunspot number. The secular decrease of the equatorial rotation rate that accompanies the increase in activity stopped in the last part of the twentieth century. It was noted that when a significant peak in equatorial rotation velocity is observed during activity minimum, the next maximum is weaker than the previous one.

  12. A new maximum power point method based on a sliding mode approach for solar energy harvesting

    International Nuclear Information System (INIS)

    Farhat, Maissa; Barambones, Oscar; Sbita, Lassaad

    2017-01-01

    Highlights: • Create a simple, easy of implement and accurate V_M_P_P estimator. • Stability analysis of the proposed system based on the Lyapunov’s theory. • A comparative study versus P&O, highlight SMC good performances. • Construct a new PS-SMC algorithm to include the partial shadow case. • Experimental validation of the SMC MPP tracker. - Abstract: This paper presents a photovoltaic (PV) system with a maximum power point tracking (MPPT) facility. The goal of this work is to maximize power extraction from the photovoltaic generator (PVG). This goal is achieved using a sliding mode controller (SMC) that drives a boost converter connected between the PVG and the load. The system is modeled and tested under MATLAB/SIMULINK environment. In simulation, the sliding mode controller offers fast and accurate convergence to the maximum power operating point that outperforms the well-known perturbation and observation method (P&O). The sliding mode controller performance is evaluated during steady-state, against load varying and panel partial shadow (PS) disturbances. To confirm the above conclusion, a practical implementation of the maximum power point tracker based sliding mode controller on a hardware setup is performed on a dSPACE real time digital control platform. The data acquisition and the control system are conducted all around dSPACE 1104 controller board and its RTI environment. The experimental results demonstrate the validity of the proposed control scheme over a stand-alone real photovoltaic system.

  13. Scalable pumping approach for extracting the maximum TEM(00) solar laser power.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana; Vistas, Cláudia R

    2014-10-20

    A scalable TEM(00) solar laser pumping approach is composed of four pairs of first-stage Fresnel lens-folding mirror collectors, four fused-silica secondary concentrators with light guides of rectangular cross-section for radiation homogenization, four hollow two-dimensional compound parabolic concentrators for further concentration of uniform radiations from the light guides to a 3 mm diameter, 76 mm length Nd:YAG rod within four V-shaped pumping cavities. An asymmetric resonator ensures an efficient large-mode matching between pump light and oscillating laser light. Laser power of 59.1 W TEM(00) is calculated by ZEMAX and LASCAD numerical analysis, revealing 20 times improvement in brightness figure of merit.

  14. Maximum Exergetic Efficiency Operation of a Solar Powered H2O-LiBr Absorption Cooling System

    Directory of Open Access Journals (Sweden)

    Camelia Stanciu

    2017-12-01

    Full Text Available A solar driven cooling system consisting of a single effect H2O-LiBr absorbtion cooling module (ACS, a parabolic trough collector (PTC, and a storage tank (ST module is analyzed during one full day operation. The pressurized water is used to transfer heat from PTC to ST and to feed the ACS desorber. The system is constrained to operate at the maximum ACS exergetic efficiency, under a time dependent cooling load computed on 15 July for a one storey house located near Bucharest, Romania. To set up the solar assembly, two commercial PTCs were selected, namely PT1-IST and PTC 1800 Solitem, and a single unit ST was initially considered. The mathematical model, relying on the energy balance equations, was coded under Engineering Equation Solver (EES environment. The solar data were obtained from the Meteonorm database. The numerical simulations proved that the system cannot cover the imposed cooling load all day long, due to the large variation of water temperature inside the ST. By splitting the ST into two units, the results revealed that the PT1-IST collector only drives the ACS between 9 am and 4:30 pm, while the PTC 1800 one covers the entire cooling period (9 am–6 pm for optimum ST capacities of 90 kg/90 kg and 90 kg/140 kg, respectively.

  15. FARIMA MODELING OF SOLAR FLARE ACTIVITY FROM EMPIRICAL TIME SERIES OF SOFT X-RAY SOLAR EMISSION

    International Nuclear Information System (INIS)

    Stanislavsky, A. A.; Burnecki, K.; Magdziarz, M.; Weron, A.; Weron, K.

    2009-01-01

    A time series of soft X-ray emission observed by the Geostationary Operational Environment Satellites from 1974 to 2007 is analyzed. We show that in the solar-maximum periods the energy distribution of soft X-ray solar flares for C, M, and X classes is well described by a fractional autoregressive integrated moving average model with Pareto noise. The model incorporates two effects detected in our empirical studies. One effect is a long-term dependence (long-term memory), and another corresponds to heavy-tailed distributions. The parameters of the model: self-similarity exponent H, tail index α, and memory parameter d are statistically stable enough during the periods 1977-1981, 1988-1992, 1999-2003. However, when the solar activity tends to minimum, the parameters vary. We discuss the possible causes of this evolution and suggest a statistically justified model for predicting the solar flare activity.

  16. Seismic Holography of Solar Activity

    Science.gov (United States)

    Lindsey, Charles

    2000-01-01

    The basic goal of the project was to extend holographic seismic imaging techniques developed under a previous NASA contract, and to incorporate phase diagnostics. Phase-sensitive imaging gives us a powerful probe of local thermal and Doppler perturbations in active region subphotospheres, allowing us to map thermal structure and flows associated with "acoustic moats" and "acoustic glories". These remarkable features were discovered during our work, by applying simple acoustic power holography to active regions. Included in the original project statement was an effort to obtain the first seismic images of active regions on the Sun's far surface.

  17. Prospective Out-of-ecliptic White-light Imaging of Interplanetary Corotating Interaction Regions at Solar Maximum

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Ming; Yang, Liping; Liu, Ying D.; Keiji, Hayashi; Li, Huichao [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Davies, Jackie A.; Harrison, Richard A. [RAL Space, STFC-Rutherford Appleton Laboratory, Harwell Campus, Didcot (United Kingdom); Li, Bo; Xia, Lidong, E-mail: mxiong@spacweather.ac.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai (China)

    2017-07-20

    Interplanetary corotating interaction regions (CIRs) can be remotely imaged in white light (WL), as demonstrated by the Solar Mass Ejection Imager (SMEI) on board the Coriolis spacecraft and Heliospheric Imagers (HIs) on board the twin Solar TErrestrial RElations Observatory ( STEREO ) spacecraft. The interplanetary WL intensity, due to Thomson scattering of incident sunlight by free electrons, is jointly determined by the 3D distribution of electron number density and line-of-sight (LOS) weighting factors of the Thomson-scattering geometry. The 2D radiance patterns of CIRs in WL sky maps look very different from different 3D viewpoints. Because of the in-ecliptic locations of both the STEREO and Coriolis spacecraft, the longitudinal dimension of interplanetary CIRs has, up to now, always been integrated in WL imagery. To synthesize the WL radiance patterns of CIRs from an out-of-ecliptic (OOE) vantage point, we perform forward magnetohydrodynamic modeling of the 3D inner heliosphere during Carrington Rotation CR1967 at solar maximum. The mixing effects associated with viewing 3D CIRs are significantly minimized from an OOE viewpoint. Our forward modeling results demonstrate that OOE WL imaging from a latitude greater than 60° can (1) enable the garden-hose spiral morphology of CIRs to be readily resolved, (2) enable multiple coexisting CIRs to be differentiated, and (3) enable the continuous tracing of any interplanetary CIR back toward its coronal source. In particular, an OOE view in WL can reveal where nascent CIRs are formed in the extended corona and how these CIRs develop in interplanetary space. Therefore, a panoramic view from a suite of wide-field WL imagers in a solar polar orbit would be invaluable in unambiguously resolving the large-scale longitudinal structure of CIRs in the 3D inner heliosphere.

  18. Performance experiments with alternative advanced teleoperator control modes for a simulated solar maximum satellite repair

    Science.gov (United States)

    Das, H.; Zak, H.; Kim, W. S.; Bejczy, A. K.; Schenker, P. S.

    1992-01-01

    Experiments are described which were conducted at the JPL Advanced Teleoperator Lab to demonstrate and evaluate the effectiveness of various teleoperator control modes in the performance of a simulated Solar Max Satellite Repair (SMSR) task. THe SMSR was selected as a test because it is very rich in performance capability requirements and it actually has been performed by two EVA astronauts in the Space Shuttle Bay in 1984. The main subtasks are: thermal blanket removal; installation of a hinge attachment for electrical panel opening; opening of electrical panel; removal of electrical connectors; relining of cable bundles; replacement of electrical panel; securing parts and cables; re-mate electrical connectors; closing of electrical panel; and reinstating thermal blanket. The current performance experiments are limited to thermal blanket cutting, electrical panel unbolting and handling electrical bundles and connectors. In one formal experiment even different control modes were applied to the unbolting and reinsertion of electrical panel screws subtasks. The seven control modes are alternative combinations of manual position and rate control with force feedback and remote compliance referenced to force-torque sensor information. Force-torque sensor and end effector position data and task completion times were recorded for analysis and quantification of operator performance.

  19. Active solar heating industry development study

    International Nuclear Information System (INIS)

    1995-01-01

    Despite the fact that solar water heating systems are technologically viable and commercially available, this Energy Technology Support Unit report shows that there is no established market in the United Kingdom. The Solar Trade Association (STA) has undertaken an Active Solar Heating Industry Development Study which is reported here. The data is derived from a questionnaire survey completed by companies, organizations and individuals operating within the industry. Information was also gathered from utility companies, and STAs elsewhere in Europe. Barriers which need to be overcome include lack of public awareness, especially in the construction industry, lack of capital investment and other financial disincentives, little or no government support, and lack of organization and quality monitoring and assurance within the industry itself. (UK)

  20. Active Longitude and Solar Flare Occurrences

    Science.gov (United States)

    Gyenge, N.; Ludmány, A.; Baranyi, T.

    2016-02-01

    The aim of the present work is to specify the spatio-temporal characteristics of flare activity observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Geostationary Operational Environmental Satellite (GOES) in connection with the behavior of the longitudinal domain of enhanced sunspot activity known as active longitude (AL). By using our method developed for this purpose, we identified the AL in every Carrington Rotation provided by the Debrecen Photoheliographic Data. The spatial probability of flare occurrence has been estimated depending on the longitudinal distance from AL in the northern and southern hemispheres separately. We have found that more than 60% of the RHESSI and GOES flares is located within +/- 36^\\circ from the AL. Hence, the most flare-productive active regions tend to be located in or close to the active longitudinal belt. This observed feature may allow for the prediction of the geo-effective position of the domain of enhanced flaring probability. Furthermore, we studied the temporal properties of flare occurrence near the AL and several significant fluctuations were found. More precisely, the results of the method are the following fluctuations: 0.8, 1.3, and 1.8 years. These temporal and spatial properties of the solar flare occurrence within the active longitudinal belts could provide us with an enhanced solar flare forecasting opportunity.

  1. Solar activity influence on climatic variations of stratosphere and mesosphere in mid-latitudes

    International Nuclear Information System (INIS)

    Taubenheim, J.; Entzian, G.; Voncossart, G.

    1989-01-01

    The direct modulation of temperature of the mid-latitude mesosphere by the solar-cycle EUV variation, which leads to greater heat input at higher solar activity, is well established. Middle atmosphere temperature modulation by the solar cycle is independently confirmed by the variation of reflection heights of low frequency radio waves in the lower ionosphere, which are regularly monitored over about 30 years. As explained elsewhere in detail, these reflection heights depend on the geometric altitude of a certain isobaric surface (near 80 k), and on the solar ionizing Lyman-alpha radiation flux. Knowing the solar cycle variation of Lyman-alpha how much the measured reflection heights would be lowered with the transition from solar minimum to maximum can be calculated, if the vertical baric structure of the neutral atmosphere would remain unchanged. Any discrepancy between expected and observed height change must be explained by an uplifting of the isobaric level from solar minimum to maximum, caused by the temperature rise in the mesosphere. By integrating the solar cycle temperature changes over the height region of the middle atmosphere, and assuming that the lower boundary (tropopause) has no solar cycle variation, the magnitude of this uplifting can be estimated. It is given for the Lidar-derived and for the rocket-measured temperature variations. Comparison suggests that the real amplitude of the solar cycle temperature variation in the mesosphere is underestimated when using the rocket data, but probably overestimated with the Lidar data

  2. Impacts of Stratospheric Dynamics on Atmospheric Behavior from the Ground to Space Solar Minimum and Solar Maximum

    Science.gov (United States)

    2015-12-15

    propagating , planetary-scale waves (wavenumber 1 and wavenumber 2) in the lower thermosphere that are associated with different stratospheric conditions. To...prominent meridional propagation of wave activity from the mid- latitudes toward the tropics. In combination with strong eastward meridional wind shear, our...Neutral and Ionized Atmosphere, Whole Atmosphere Model, and WACCM-X. The comparison focuses on the zonal mean, planetary wave , and tidal variability in

  3. Statistical Analysis of Solar Events Associated with SSC over Year of Solar Maximum during Cycle 23: 1. Identification of Related Sun-Earth Events

    Science.gov (United States)

    Grison, B.; Bocchialini, K.; Menvielle, M.; Chambodut, A.; Cornilleau-Wehrlin, N.; Fontaine, D.; Marchaudon, A.; Pick, M.; Pitout, F.; Schmieder, B.; Regnier, S.; Zouganelis, Y.

    2017-12-01

    Taking the 32 sudden storm commencements (SSC) listed by the observatory de l'Ebre / ISGI over the year 2002 (maximal solar activity) as a starting point, we performed a statistical analysis of the related solar sources, solar wind signatures, and terrestrial responses. For each event, we characterized and identified, as far as possible, (i) the sources on the Sun (Coronal Mass Ejections -CME-), with the help of a series of herafter detailed criteria (velocities, drag coefficient, radio waves, polarity), as well as (ii) the structure and properties in the interplanetary medium, at L1, of the event associated to the SSC: magnetic clouds -MC-, non-MC interplanetary coronal mass ejections -ICME-, co-rotating/stream interaction regions -SIR/CIR-, shocks only and unclear events that we call "miscellaneous" events. The categorization of the events at L1 is made on published catalogues. For each potential CME/L1 event association we compare the velocity observed at L1 with the one observed at the Sun and the estimated balistic velocity. Observations of radio emissions (Type II, Type IV detected from the ground and /or by WIND) associated to the CMEs make the solar source more probable. We also compare the polarity of the magnetic clouds with the hemisphere of the solar source. The drag coefficient (estimated with the drag-based model) is calculated for each potential association and it is compared to the expected range values. We identified a solar source for 26 SSC related events. 12 of these 26 associations match all criteria. We finally discuss the difficulty to perform such associations.

  4. In-flight calibration and performance evaluation of the fixed head star trackers for the solar maximum mission

    Science.gov (United States)

    Thompson, R. H.; Gambardella, P. J.

    1980-01-01

    The Solar Maximum Mission (SMM) spacecraft provides an excellent opportunity for evaluating attitude determination accuracies achievable with tracking instruments such as fixed head star trackers (FHSTs). As a part of its payload, SMM carries a highly accurate fine pointing Sun sensor (FPSS). The EPSS provides an independent check of the pitch and yaw parameters computed from observations of stars in the FHST field of view. A method to determine the alignment of the FHSTs relative to the FPSS using spacecraft data is applied. Two methods that were used to determine distortions in the 8 degree by 8 degree field of view of the FHSTs using spacecraft data are also presented. The attitude determination accuracy performance of the in flight calibrated FHSTs is evaluated.

  5. The Torsional Oscillation and the Timing of the Solar Cycle: Is it Maximum Yet?

    DEFF Research Database (Denmark)

    Howe, R.; Christensen-Dalsgaard, J.; Hill, F.

    2013-01-01

    After the late start to Cycle 24 there are some indications that activity may have peaked as early as late 2011 and that the polar-field reversal has already occurred in the North. We use helioseismic measurements of the migrating zonal flow pattern known as the torsional oscillation to estimate...

  6. The Relation between Coronal Holes and Coronal Mass Ejections during the Rise, Maximum, and Declining Phases of Solar Cycle 23

    Science.gov (United States)

    Mohamed, A. A.; Gopalswamy, N; Yashiro, S.; Akiyama, S.; Makela, P.; Xie, H.; Jung, H.

    2012-01-01

    We study the interaction between coronal holes (CHs) and coronal mass ejections (CMEs) using a resultant force exerted by all the coronal holes present on the disk and is defined as the coronal hole influence parameter (CHIP). The CHIP magnitude for each CH depends on the CH area, the distance between the CH centroid and the eruption region, and the average magnetic field within the CH at the photospheric level. The CHIP direction for each CH points from the CH centroid to the eruption region. We focus on Solar Cycle 23 CMEs originating from the disk center of the Sun (central meridian distance =15deg) and resulting in magnetic clouds (MCs) and non-MCs in the solar wind. The CHIP is found to be the smallest during the rise phase for MCs and non-MCs. The maximum phase has the largest CHIP value (2.9 G) for non-MCs. The CHIP is the largest (5.8 G) for driverless (DL) shocks, which are shocks at 1 AU with no discernible MC or non-MC. These results suggest that the behavior of non-MCs is similar to that of the DL shocks and different from that of MCs. In other words, the CHs may deflect the CMEs away from the Sun-Earth line and force them to behave like limb CMEs with DL shocks. This finding supports the idea that all CMEs may be flux ropes if viewed from an appropriate vantage point.

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

    International Nuclear Information System (INIS)

    Watanabe, Tetsuya

    2008-01-01

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

  8. Cosmic rays, solar activity and the climate

    International Nuclear Information System (INIS)

    Sloan, T; Wolfendale, A W

    2013-01-01

    Although it is generally believed that the increase in the mean global surface temperature since industrialization is caused by the increase in green house gases in the atmosphere, some people cite solar activity, either directly or through its effect on cosmic rays, as an underestimated contributor to such global warming. In this letter a simplified version of the standard picture of the role of greenhouse gases in causing the global warming since industrialization is described. The conditions necessary for this picture to be wholly or partially wrong are then introduced. Evidence is presented from which the contributions of either cosmic rays or solar activity to this warming is deduced. The contribution is shown to be less than 10% of the warming seen in the twentieth century. (letter)

  9. Does solar activity affect human happiness?

    Science.gov (United States)

    Kristoufek, Ladislav

    2018-03-01

    We investigate the direct influence of solar activity (represented by sunspot numbers) on human happiness (represented by the Twitter-based Happiness Index). We construct four models controlling for various statistical and dynamic effects of the analyzed series. The final model gives promising results. First, there is a statistically significant negative influence of solar activity on happiness which holds even after controlling for the other factors. Second, the final model, which is still rather simple, explains around 75% of variance of the Happiness Index. Third, our control variables contribute significantly as well: happiness is higher in no sunspots days, happiness is strongly persistent, there are strong intra-week cycles and happiness peaks during holidays. Our results strongly contribute to the topical literature and they provide evidence of unique utility of the online data.

  10. Imaging x-ray spectrometer to study solar activity in conjunction with the SCADM program

    International Nuclear Information System (INIS)

    Blake, R.L.

    1979-01-01

    An experiment is proposed to study solar active region dynamics and evolution. It will greatly extend the range of capabilities provided by the Solar Maximum Mission. The larger volume and weight capacity of a shuttle launch make possible an experiment with enough sensitivity to study the fastest known solar phenomena with high spatial and spectral resolution. It will be possible to use high spectral resolving power to image events on a small scale in short time intervals, and it will be possible to use this tremendous diagnostic power from the instant of event onset. Similar sensitivity will be available for the study of active region morphology and evolution

  11. Energetic evaluation of the largest geomagnetic storms of solar cycle 24 on March 17, 2015 and September 8, 2017 during solar maximum and minimum, respectively

    International Nuclear Information System (INIS)

    Tomova, Dimitrinka; Velinov, Peter; Tassev, Yordan; Tomova, Dimitrinka

    2018-01-01

    Some of the most powerful Earth’s directed coronal mass ejections (CMEs) from the current 24 solar cycle have been investigated. These are CMEs on March 15, 2015 and on September 4 and 6, 2017. As a result of these impacts of Sun on Earth, the highest intensity of the geomagnetic storms for the 24th solar cycle is observed. These G4 – Severe geomagnetic storms are in the periods March 17÷19, 2015 and September 7÷10, 2017. We use the solar wind parameters (velocity V, density or concentration N , temperature T p and intensity of the magnetic field B) from measurements by WIND, ACE and SOHO space crafts in the Lagrange equilibrium point L1 between Sun and Earth. We make calculations for the kinetic (dynamic) energy density E k , thermal energy density E t and magnetic energy density E m during the investigated periods May 10÷24, 2015 and September 2÷16, 2017. Both the energy densities for the individual events and the cumulative energy for each of them are evaluated. The quantitative analysis shows that not always the size of the geomagnetic reaction is commensurate with the density of the energy flux reaching the magnetosphere. In both studied periods, the energy densities have different behaviour over time. But for both periods, we can talk about the prognostic effect – with varying degrees of increase of the dynamic and thermal energies. Such an effect is not observed in the density of magnetic energy. An inverse relationship between the magnitude of the density of energies and the effect of Forbush decrease of the galactic cosmic rays is established. Key words: solar activity, flares, coronal mass ejection (CME), G4 –Severe geomagnetic storms, energy density of the solar wind, space weather

  12. Cyclotron Line in Solar Microwave Radiation by Radio Telescope RATAN-600 Observations of the Solar Active Region NOAA 12182

    Science.gov (United States)

    Peterova, N. G.; Topchilo, N. A.

    2017-12-01

    This paper presents the results of observation of a rare phenomenon—a narrowband increase in the brightness of cyclotron radiation of one of the structural details of a radio source located in the solar corona above the solar active region NOAA 12182 in October 2014 at a frequency of 4.2 ± 0.1 GHz. The brightness of radiation in the maximum of the phenomenon has reached 10 MK; its duration was equal to 3 s. The exact location of the source of the narrowband cyclotron radiation is indicated: it is a corona above a fragmented (4-nuclear) sunspot, on which a small UV flare loop was closed.

  13. Solar activity simulation and forecast with a flux-transport dynamo

    Science.gov (United States)

    Macario-Rojas, Alejandro; Smith, Katharine L.; Roberts, Peter C. E.

    2018-06-01

    We present the assessment of a diffusion-dominated mean field axisymmetric dynamo model in reproducing historical solar activity and forecast for solar cycle 25. Previous studies point to the Sun's polar magnetic field as an important proxy for solar activity prediction. Extended research using this proxy has been impeded by reduced observational data record only available from 1976. However, there is a recognised need for a solar dynamo model with ample verification over various activity scenarios to improve theoretical standards. The present study aims to explore the use of helioseismology data and reconstructed solar polar magnetic field, to foster the development of robust solar activity forecasts. The research is based on observationally inferred differential rotation morphology, as well as observed and reconstructed polar field using artificial neural network methods via the hemispheric sunspot areas record. Results show consistent reproduction of historical solar activity trends with enhanced results by introducing a precursor rise time coefficient. A weak solar cycle 25, with slow rise time and maximum activity -14.4% (±19.5%) with respect to the current cycle 24 is predicted.

  14. Transient flows of the solar wind associated with small-scale solar activity in solar minimum

    Science.gov (United States)

    Slemzin, Vladimir; Veselovsky, Igor; Kuzin, Sergey; Gburek, Szymon; Ulyanov, Artyom; Kirichenko, Alexey; Shugay, Yulia; Goryaev, Farid

    The data obtained by the modern high sensitive EUV-XUV telescopes and photometers such as CORONAS-Photon/TESIS and SPHINX, STEREO/EUVI, PROBA2/SWAP, SDO/AIA provide good possibilities for studying small-scale solar activity (SSA), which is supposed to play an important role in heating of the corona and producing transient flows of the solar wind. During the recent unusually weak solar minimum, a large number of SSA events, such as week solar flares, small CMEs and CME-like flows were observed and recorded in the databases of flares (STEREO, SWAP, SPHINX) and CMEs (LASCO, CACTUS). On the other hand, the solar wind data obtained in this period by ACE, Wind, STEREO contain signatures of transient ICME-like structures which have shorter duration (<10h), weaker magnetic field strength (<10 nT) and lower proton temperature than usual ICMEs. To verify the assumption that ICME-like transients may be associated with the SSA events we investigated the number of weak flares of C-class and lower detected by SPHINX in 2009 and STEREO/EUVI in 2010. The flares were classified on temperature and emission measure using the diagnostic means of SPHINX and Hinode/EIS and were confronted with the parameters of the solar wind (velocity, density, ion composition and temperature, magnetic field, pitch angle distribution of the suprathermal electrons). The outflows of plasma associated with the flares were identified by their coronal signatures - CMEs (only in few cases) and dimmings. It was found that the mean parameters of the solar wind projected to the source surface for the times of the studied flares were typical for the ICME-like transients. The results support the suggestion that weak flares can be indicators of sources of transient plasma flows contributing to the slow solar wind at solar minimum, although these flows may be too weak to be considered as separate CMEs and ICMEs. The research leading to these results has received funding from the European Union’s Seventh Programme

  15. The Heliosphere through the Solar Activity Cycle

    CERN Document Server

    Balogh, André; Suess, Steven T

    2008-01-01

    Understanding how the Sun changes though its 11-year sunspot cycle and how these changes affect the vast space around the Sun – the heliosphere – has been one of the principal objectives of space research since the advent of the space age. This book presents the evolution of the heliosphere through an entire solar activity cycle. The last solar cycle (cycle 23) has been the best observed from both the Earth and from a fleet of spacecraft. Of these, the joint ESA-NASA Ulysses probe has provided continuous observations of the state of the heliosphere since 1990 from a unique vantage point, that of a nearly polar orbit around the Sun. Ulysses’ results affect our understanding of the heliosphere from the interior of the Sun to the interstellar medium - beyond the outer boundary of the heliosphere. Written by scientists closely associated with the Ulysses mission, the book describes and explains the many different aspects of changes in the heliosphere in response to solar activity. In particular, the authors...

  16. Great red spot dependence on solar activity

    International Nuclear Information System (INIS)

    Schatten, K.H.

    1979-01-01

    A new inquiry has been made into the question of whether Jupiter's Great Red Spot shows a solar activity dependence. From 1892 to 1947 a clear correlation was present. A dearth of sightings in the seventeenth century, along with the Maunder Minimum, further supports the relation. An anticorrelation, however, from l948 to l967 removed support for such an effect. The old observations have reexamined and recent observations have also been studied. The author reexamines this difficult question and suggests a possible physical mechanism for a Sun-Jovian weather relation. Prinn and Lewis' conversion reaction of Phosphine gas to triclinic red phosphorous crystals is a reaction dependent upon solar radiation. It may explain the dependence found, as well as the striking appearance of the Great Red Spot in the UV

  17. Interplanetary variability recorded by the sled instrument aboard the Phobos spacecraft during that period of solar cycle 22 characterized by a transition from solar minimum- to solar maximum-dominated conditions

    Energy Technology Data Exchange (ETDEWEB)

    McKenna-Lawlor, S.M.P. (Saint Patrick' s Coll., Maynooth (Ireland)); Afonin, V.V.; Gringauz, K.I. (AN SSSR, Moscow (USSR). Space Research Inst.) (and others)

    Twin telescope particle detector systems SLED-1 and SLED-2, with the capability of monitoring electron and ion fluxes within an energy range spanning approximately 30 keV to a few megaelectron volts, were individually launched on the two spacecraft (Phobos-2 and Phobos-1, respectively) of the Soviet Phobos Mission to Mars and its moons in July 1988. A short description of the SLED instrument and a preliminary account of representative solar-related particle enhancements recorded by SLED-1 and SLED-2 during the Cruise Phase, and by SLED-1 in the near Martian environment (within the interval 25 July 1988-26 March 1989) are presented. These observations were made while the interplanetary medium was in the course of changing over from solar minimum- to solar maximum-dominated conditions and examples are presented of events associated with each of these phenomenological states. (author).

  18. MASC: Magnetic Activity of the Solar Corona

    Science.gov (United States)

    Auchere, Frederic; Fineschi, Silvano; Gan, Weiqun; Peter, Hardi; Vial, Jean-Claude; Zhukov, Andrei; Parenti, Susanna; Li, Hui; Romoli, Marco

    We present MASC, an innovative payload designed to explore the magnetic activity of the solar corona. It is composed of three complementary instruments: a Hard-X-ray spectrometer, a UV / EUV imager, and a Visible Light / UV polarimetric coronagraph able to measure the coronal magnetic field. The solar corona is structured in magnetically closed and open structures from which slow and fast solar winds are respectively released. In spite of much progress brought by two decades of almost uninterrupted observations from several space missions, the sources and acceleration mechanisms of both types are still not understood. This continuous expansion of the solar atmosphere is disturbed by sporadic but frequent and violent events. Coronal mass ejections (CMEs) are large-scale massive eruptions of magnetic structures out of the corona, while solar flares trace the sudden heating of coronal plasma and the acceleration of electrons and ions to high, sometimes relativistic, energies. Both phenomena are most probably driven by instabilities of the magnetic field in the corona. The relations between flares and CMEs are still not understood in terms of initiation and energy partition between large-scale motions, small-scale heating and particle acceleration. The initiation is probably related to magnetic reconnection which itself results magnetic topological changes due to e.g. flux emergence, footpoints motions, etc. Acceleration and heating are also strongly coupled since the atmospheric heating is thought to result from the impact of accelerated particles. The measurement of both physical processes and their outputs is consequently of major importance. However, despite its fundamental importance as a driver for the physics of the Sun and of the heliosphere, the magnetic field of our star’s outer atmosphere remains poorly understood. This is due in large part to the fact that the magnetic field is a very difficult quantity to measure. Our knowledge of its strength and

  19. Variations of Solar Non-axisymmetric Activity

    Science.gov (United States)

    Gyenge, N.; Baranyi, T.; Ludmány, A.

    The temporal behaviour of solar active longitudes has been examined by using two sunspot catalogues, the Greenwich Photoheliographic Results (GPR) and the Debrecen Photoheliographic Data (DPD). The time-longitude diagrams of the activity distribution reveal the preferred longitudinal zones and their migration with respect to the Carrington frame. The migration paths outline a set of patterns in which the activity zone has alternating prograde/retrograde angular velocities with respect to the Carrington rotation rate. The time profiles of these variations can be described by a set of successive parabolae. Two similar migration paths have been selected from these datasets, one northern path during cycles 21 - 22 and one southern path during cycles 13 - 14, for closer examination and comparison of their dynamical behaviours. The rates of sunspot emergence exhibited in both migration paths similar periodicities, close to 1.3 years. This behaviour may imply that the active longitude is connected to the bottom of convection zone.

  20. Semi-annual Sq-variation in solar activity cycle

    Science.gov (United States)

    Pogrebnoy, V.; Malosiev, T.

    The peculiarities of semi-annual variation in solar activity cycle have been studied. The data from observatories having long observational series and located in different latitude zones were used. The following observatories were selected: Huancayo (magnetic equator), from 1922 to 1959; Apia (low latitudes), from 1912 to 1961; Moscow (middle latitudes), from 1947 to 1965. Based on the hourly values of H-components, the average monthly diurnal amplitudes (a difference between midday and midnight values), according to five international quiet days, were computed. Obtained results were compared with R (relative sunspot numbers) in the ranges of 0-30R, 40-100R, and 140-190R. It was shown, that the amplitude of semi-annual variation increases with R, from minimum to maximum values, on average by 45%. At equatorial Huancayo observatory, the semi-annual Sq(H)-variation appears especially clearly: its maximums take place at periods of equinoxes (March-April, September-October), and minimums -- at periods of solstices (June-July, December-January). At low (Apia observatory) and middle (Moscow observatory) latitudes, the character of semi-annual variation is somewhat different: it appears during the periods of equinoxes, but considerably less than at equator. Besides, with the growth of R, semi-annual variation appears against a background of annual variation, in the form of second peaks (maximum in June). At observatories located in low and middle latitudes, second peaks become more appreciable with an increase of R (March-April and September-October). During the periods of low solar activity, they are insignificant. This work has been carried out with the support from International Scientific and Technology Center (Project #KR-214).

  1. Height of the E layer as a function of solar activity

    International Nuclear Information System (INIS)

    Antonova, L.A.; Ivanov-Kholodnyj, G.S.; Zhivolup, T.G.

    1992-01-01

    Variations of h m E height of E layer maximum with solar activity are investigated using data of from rocket measurements. These data are contradictory ones and requires more exact definition. h m E decrease with growth of solar activity is predicted theoretically: small monotone decrease during solar cycle on the one hand, and/or jump-like decrease of h m E at a certain intermediate value of F 10.7 - on the other hand. New rather reliable results are obtained due to data from incoherent dissipation station. On the basis of these measurements it is obtained that at low and even at rather high solar activity there is a small monotone decrease of h m E, while at intermediate activity, when F 10.7 =140-180 there occurs more abrupt variation of h m E

  2. Morphology of equatorial plasma bubbles during low and high solar activity years over Indian sector

    Science.gov (United States)

    Kumar, Sanjay

    2017-05-01

    In the present study, slant total electron content (STEC) data computed from ground based GPS measurements over Hyderabad (Geog. Lat. 17.41° N, geog. long. 78.55° E, mag. lat. 08.81° N) and two close stations at Bangalore (Geog. Lat. 13.02°/13.03° N, geog. long. 77.57°/77.51° E, mag. lat. 04.53°/04.55° N) in Indian region during 2007-2012, have been used to study the occurrences and characteristics of equatorial plasma bubbles (EPBs). The analysis found maximum EPB occurrences during the equinoctial months and minimum during the December solstice throughout 2007-2012 except during the solar minimum years in 2007-2009. During 2007-2009, the maximum EPB occurrences were observed in June solstice which could not be predicted by the model proposed by Tsunoda (J. Geophys. Res., 90:447-456, 1985). The equinox maximum in EPB occurrences for high solar activity years could be caused by the vertical F-layer drift due to pre-reversal electric field (PRE), and expected to be maximum when day-night terminator aligns with the magnetic meridian i.e. during the equinox months whereas maximum occurrences during the solstice months of solar minimum could be caused by the seed perturbation in plasma density induced by gravity waves from tropospheric origins. Generally EPB occurrences are found to be more prominent during nighttime hours (2000-2400 hours) than the daytime hours. Peak in EPB occurrences is in early night for high solar activity years whereas same is late night for low solar activity. The day and nighttime EPB occurrences have been analyzed and found to vary in accordance with solar activity with an annual correlation coefficient (R) of ˜0.99 with F_{10.7} cm solar Flux. Additionally, solar activity influence on EPB occurrences is seasonal dependent with a maximum influence during the equinox season (R=0.88) and a minimum during winter season (R =0.73). The solar activity influences on EPB occurrences are found in agreement with the previous works reported in

  3. Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003

    International Nuclear Information System (INIS)

    Hadorn, J.-C.; Renaud, P.

    2003-01-01

    In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD+D projects

  4. The onset of the solar active cycle 22

    International Nuclear Information System (INIS)

    Ahluwalia, H.S.

    1989-01-01

    There is a great deal of interest in being able to predict the main characteristics of a solar activity cycle (SAC). One would like to know, for instance, how large the amplitude (R sub m) of a cycle is likely to be, i.e., the annual mean of the sunspot numbers at the maximum of SAC. Also, how long a cycle is likely to last, i.e., its period. It would also be interesting to be able to predict the details, like how steep the ascending phase of a cycle is likely to be. Questions like these are of practical importance to NASA in planning the launch schedule for the low altitude, expensive spacecrafts like the Hubble Space Telescope, the Space Station, etc. Also, one has to choose a proper orbit, so that once launched the threat of an atmospheric drag on the spacecraft is properly taken into account. Cosmic ray data seem to indicate that solar activity cycle 22 will surpass SAC 21 in activity. The value of R sub m for SAC 22 may approach that of SAC 19. It would be interesting to see whether this prediction is borne out. Researchers are greatly encouraged to proceed with the development of a comprehensive prediction model which includes information provided by cosmic ray data

  5. The onset of the solar active cycle 22

    Science.gov (United States)

    Ahluwalia, H. S.

    1989-01-01

    There is a great deal of interest in being able to predict the main characteristics of a solar activity cycle (SAC). One would like to know, for instance, how large the amplitude (R sub m) of a cycle is likely to be, i.e., the annual mean of the sunspot numbers at the maximum of SAC. Also, how long a cycle is likely to last, i.e., its period. It would also be interesting to be able to predict the details, like how steep the ascending phase of a cycle is likely to be. Questions like these are of practical importance to NASA in planning the launch schedule for the low altitude, expensive spacecrafts like the Hubble Space Telescope, the Space Station, etc. Also, one has to choose a proper orbit, so that once launched the threat of an atmospheric drag on the spacecraft is properly taken into account. Cosmic ray data seem to indicate that solar activity cycle 22 will surpass SAC 21 in activity. The value of R sub m for SAC 22 may approach that of SAC 19. It would be interesting to see whether this prediction is borne out. Researchers are greatly encouraged to proceed with the development of a comprehensive prediction model which includes information provided by cosmic ray data.

  6. Differences in hamstring activation characteristics between the acceleration and maximum-speed phases of sprinting.

    Science.gov (United States)

    Higashihara, Ayako; Nagano, Yasuharu; Ono, Takashi; Fukubayashi, Toru

    2018-06-01

    This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the acceleration sprint and maximum-speed sprint in 13 male sprinters during an overground sprinting. Differences in hamstring activation during each divided phases and in the hip and knee joint angles and torques at each time point of the sprinting gait cycle were determined between two sprints. During the early stance of the acceleration sprint, the hip extension torque was significantly greater than during the maximum-speed sprint, and the relative EMG activation of the BFlh muscle was significantly higher than that of the ST muscle. During the late stance and terminal mid-swing of maximum-speed sprint, the knee was more extended and a higher knee flexion moment was observed compared to the acceleration sprint, and the ST muscle showed higher activation than that of the BFlh. These results indicate that the functional demands of the medial and lateral hamstring muscles differ between two different sprint performances.

  7. Solar activity and transformer failures in the Greek national electric grid

    Directory of Open Access Journals (Sweden)

    Zois Ioannis Panayiotis

    2013-11-01

    Full Text Available Aims: We study both the short term and long term effects of solar activity on the large transformers (150 kV and 400 kV of the Greek national electric grid. Methods: We use data analysis and various statistical methods and models. Results: Contrary to common belief in PPC Greece, we see that there are considerable both short term (immediate and long term effects of solar activity onto large transformers in a mid-latitude country like Greece. Our results can be summarised as follows: For the short term effects: During 1989–2010 there were 43 “stormy days” (namely days with for example Ap ≥ 100 and we had 19 failures occurring during a stormy day plus or minus 3 days and 51 failures occurring during a stormy day plus or minus 7 days. All these failures can be directly related to Geomagnetically Induced Currents (GICs. Explicit cases are briefly presented. For the long term effects, again for the same period 1989–2010, we have two main results: The annual number of transformer failures seems to follow the solar activity pattern. Yet the maximum number of transformer failures occurs about half a solar cycle after the maximum of solar activity. There is statistical correlation between solar activity expressed using various newly defined long term solar activity indices and the annual number of transformer failures. These new long term solar activity indices were defined using both local (from the geomagnetic station in Greece and global (planetary averages geomagnetic data. Applying both linear and non-linear statistical regression we compute the regression equations and the corresponding coefficients of determination.

  8. The bottomside parameters B0, B1 obtained from incoherent scatter measurements during a solar maximum and their comparisons with the IRI-2001 model

    Directory of Open Access Journals (Sweden)

    N. K. Sethi

    2002-06-01

    Full Text Available High resolution electron density profiles (Ne measured with the Arecibo (18.4 N, 66.7 W, Incoherent Scatter radar (I. S. are used to obtain the bottomside shape parameters B0, B1 for a solar maximum period (1989–90. Median values of these parameters are compared with those obtained from the IRI-2001 model. It is observed that during summer, the IRI values agree fairly well with the Arecibo values, though the numbers are somewhat larger during the daytime. Discrepancies occur during winter and equinox, when the IRI underestimates B0 for the local times from about 12:00 LT to about 20:00 LT. Furthermore, the IRI model tends to generally overestimate B1 at all local times. At Arecibo, B0 increases by about 50%, and B1 decreases by about 30% from solar minimum to solar maximum.Key words. Ionosphere (equational ionosphere; modeling and forecasting

  9. Statistical analysis of solar events associated with SSC over one year of solar maximum during cycle 23: propagation and effects from the Sun to the Earth

    Science.gov (United States)

    Cornilleau-Wehrlin, Nicole; Bocchialini, Karine; Menvielle, Michel; Chambodut, Aude; Fontaine, Dominique; Grison, Benjamin; Marchaudon, Aurélie; Pick, Monique; Pitout, Frédéric; Schmieder, Brigitte; Régnier, Stéphane; Zouganelis, Yannis

    2017-04-01

    Taking the 32 sudden storm commencements (SSC) listed by the observatory de l'Ebre / ISGI over the year 2002 (maximal solar activity) as a starting point, we performed a statistical analysis of the related solar sources, solar wind signatures, and terrestrial responses. For each event, we characterized and identified, as far as possible, (i) the sources on the Sun (Coronal Mass Ejections -CME-), with the help of a series of criteria (velocities, drag coefficient, radio waves, helicity), as well as (ii) the structure and properties in the interplanetary medium, at L1, of the event associated to the SSC: magnetic clouds -MC-, non-MC interplanetary coronal mass ejections -ICME-, co-rotating/stream interaction regions -SIR/CIR-, shocks only and unclear events that we call "miscellaneous" events. The observed Sun-to-Earth travel times are compared to those estimated using existing simple models of propagation in the interplanetary medium. This comparison is used to statistically assess performances of various models. The geoeffectiveness of the events, classified by category at L1, is analysed by their signatures in the Earth ionized (magnetosphere and ionosphere) and neutral (thermosphere) environments, using a broad set of in situ, remote and ground based instrumentation. The role of the presence of a unique or of a multiple source at the Sun, of its nature, halo or non halo CME, is also discussed. The set of observations is statistically analyzed so as to evaluate and compare the geoeffectiveness of the events. The results obtained for this set of geomagnetic storms started by SSCs is compared to the overall statistics of year 2002, relying on already published catalogues of events, allowing assessing the relevance of our approach (for instance the all 12 well identified Magnetic Clouds of 2002 give rise to SSCs).

  10. Statistical analysis of solar events associated with SSC over year of solar maximum during cycle 23: 2. Characterisation on the Sun-Earth path - Geoeffectiveness

    Science.gov (United States)

    Cornilleau-Wehrlin, N.; Bocchialini, K.; Menvielle, M.; Fontaine, D.; Grison, B.; Marchaudon, A.; Pick, M.; Pitout, F.; Schmieder, B.; Regnier, S.; Zouganelis, Y.; Chambodut, A.

    2017-12-01

    Taking the 32 sudden storm commencements (SSC) listed by the observatory de l'Ebre / ISGI over the year 2002 (maximal solar activity) as a starting point, we performed a statistical analysis of the related solar sources, solar wind signatures, and terrestrial responses. For each event, we characterized and identified, as far as possible, (i) the sources on the Sun (Coronal Mass Ejections -CME-), with the help of a series of criteria (velocities, drag coefficient, radio waves, magnetic field polarity), as well as (ii) the structure and properties in the interplanetary medium, at L1, of the event associated to the SSC: magnetic clouds -MC-, non-MC interplanetary coronal mass ejections -ICME-, co-rotating/stream interaction regions -SIR/CIR-, shocks only and unclear events that we call "miscellaneous" events. The geoeffectiveness of the events, classified by category at L1, is analysed by their signatures in the Earth ionized (magnetosphere and ionosphere) and neutral (thermosphere) environments, using a broad set of in situ, remote and ground based instrumentation. The role of the presence of a unique or of a multiple source at the Sun, of its nature, halo or non halo CME, is also discussed. The set of observations is statistically analyzed so as to evaluate and compare the geoeffectiveness of the events. The results obtained for this set of geomagnetic storms started by SSCs is compared to the overall statistics of year 2002, relying on already published catalogues of events, allowing assessing the relevance of our approach ; for instance all the 12 well identified Magnetic Clouds of 2002 give rise to SSCs.

  11. Latitudinal and radial variation of >2 GeV/n protons and alpha-particles at solar maximum: ULYSSES COSPIN/KET and neutron monitor network observations

    Directory of Open Access Journals (Sweden)

    A. V. Belov

    2003-06-01

    Full Text Available Ulysses, launched in October 1990, began its second out-of-ecliptic orbit in September 1997. In 2000/2001 the spacecraft passed from the south to the north polar regions of the Sun in the inner heliosphere. In contrast to the first rapid pole to pole passage in 1994/1995 close to solar minimum, Ulysses experiences now solar maximum conditions. The Kiel Electron Telescope (KET measures also protons and alpha-particles in the energy range from 5 MeV/n to >2 GeV/n. To derive radial and latitudinal gradients for >2 GeV/n protons and alpha-particles, data from the Chicago instrument on board IMP-8 and the neutron monitor network have been used to determine the corresponding time profiles at Earth. We obtain a spatial distribution at solar maximum which differs greatly from the solar minimum distribution. A steady-state approximation, which was characterized by a small radial and significant latitudinal gradient at solar minimum, was interchanged with a highly variable one with a large radial and a small – consistent with zero – latitudinal gradient. A significant deviation from a spherically symmetric cosmic ray distribution following the reversal of the solar magnetic field in 2000/2001 has not been observed yet. A small deviation has only been observed at northern polar regions, showing an excess of particles instead of the expected depression. This indicates that the reconfiguration of the heliospheric magnetic field, caused by the reappearance of the northern polar coronal hole, starts dominating the modulation of galactic cosmic rays already at solar maximum.Key words. Interplanetary physics (cosmic rays; energetic particles – Space plasma physics (charged particle motion and acceleration

  12. Field-aligned flows of H+ and He+ in the mid-latitude topside ionosphere at solar maximum

    International Nuclear Information System (INIS)

    Bailey, G.J.; Sellek, R.

    1992-01-01

    A time-dependent mathematical model of the Earth's ionosphere and plasmasphere has been used to investigate the field-aligned flows of H + and He + in the topside ionosphere at L = 3 during solar maximum. When the flux-tube content is low there are upward flows of H + and He + during daytime in both the winter and summer topside ionospheres. During winter night-time the directions of flow are, in general, downwards for He + , because of the night-time decrease in He + scale height, and upwards for H + , because of the replenishment needs of the flux tube. In the winter topside ionosphere, during the later stages of flux-tube replenishment, H + generally flows downwards during both day and night as a result of the greater plasma pressure in the summer hemisphere whilst He + flows upwards during the day and downwards at night. In the summer topside ionosphere H + flows upward to replace the H + lost from the plasmasphere to the winter topside ionosphere whilst the winter helium bulge leads to flows of He + that are in the direction winter hemisphere to summer hemisphere. When the flux-tube content is low, counterstreaming of H + and He + , with H + flowing upwards and He + downwards, occurs for most of the day above about 5000 km altitude in the summer hemisphere. There are occurrences of this type of counterstreaming in both the summer and winter hemispheres during the night. When the flux-tube content is high, counterstreaming of H + and He + occurs less frequently and over smaller regions of the flux tube. There are regions in both hemispheres where H + flows downwards whilst He + flows upwards. (Author)

  13. Apparent Relations Between Solar Activity and Solar Tides Caused by the Planets

    Science.gov (United States)

    Hung, Ching-Cheh

    2007-01-01

    A solar storm is a storm of ions and electrons from the Sun. Large solar storms are usually preceded by solar flares, phenomena that can be characterized quantitatively from Earth. Twenty-five of the thirty-eight largest known solar flares were observed to start when one or more tide-producing planets (Mercury, Venus, Earth, and Jupiter) were either nearly above the event positions (less than 10 deg. longitude) or at the opposing side of the Sun. The probability for this to happen at random is 0.039 percent. This supports the hypothesis that the force or momentum balance (between the solar atmospheric pressure, the gravity field, and magnetic field) on plasma in the looping magnetic field lines in solar corona could be disturbed by tides, resulting in magnetic field reconnection, solar flares, and solar storms. Separately, from the daily position data of Venus, Earth, and Jupiter, an 11-year planet alignment cycle is observed to approximately match the sunspot cycle. This observation supports the hypothesis that the resonance and beat between the solar tide cycle and nontidal solar activity cycle influences the sunspot cycle and its varying magnitudes. The above relations between the unpredictable solar flares and the predictable solar tidal effects could be used and further developed to forecast the dangerous space weather and therefore reduce its destructive power against the humans in space and satellites controlling mobile phones and global positioning satellite (GPS) systems.

  14. Distribution of activity at the solar active longitudes between 1979 - 2011 in the northern hemisphere

    Science.gov (United States)

    Gyenge, N.; Baranyi, T.; Ludmány, A.

    The solar active longitudes were studied in the northern hemisphere in cycles 22 and 23 by using data of DPD sunspot catalogue. The active longitudes are not fixed in the Carrington system, they have a well recognizable migration path between the descending phase of cycle 21 (from about 1984) and ascending phase of cycle 23 (until about 1996), out of this interval the migration path is ambiguous. The longitudinal distribution on both sides of the path has been computed and averaged for the length of the path. The so-called flip-flop phenomenon, when the activity temporarily gets to the opposite longitude, can also be recognized. The widths of the active domains are fairly narrow in the increasing and decaying phases of cycle 22, their half widths are about 20°-30° for both the main and secondary active belts but it is more flat and stretched around the maximum with a half width of about 60°.

  15. The Influence of Red Fruit Oil on Creatin Kinase Level at Maximum Physical Activity

    Science.gov (United States)

    Apollo Sinaga, Fajar; Hotliber Purba, Pangondian

    2018-03-01

    Heavy physical activities can cause the oxidative stress which resulting in muscle damage with an indicator of elevated levels of Creatin Kinase (CK) enzyme. The oxidative stress can be prevented or reduced by antioxidant supplementation. One of natural resources which contain antioxidant is Red Fruit (Pandanus conoideus) Oil (RFO). This study aims to see the effect of Red Fruit Oil on Creatin Kinase (CK) level at maximum physical activity. This study is an experimental research by using the design of randomized control group pretest-posttest. This study was using 24 male mice divided into four groups, the control group was given aquadest, the treatment groups P1, P2, and P3 were given the RFO orally of 0.15 ml/kgBW, 0.3 ml/kgBW, and 0.6 ml/kgBW, respectively, for a month. The level of CK was checked for all groups at the beginning of study and after the maximum physical activity. The obtained data were then tested statistically by using t-test and ANOVA. The result shows the RFO supplementation during exercise decreased the CK level in P1, P2, and P3 groups with p<0.05, and the higher RFO dosage resulted in decreased CK level at p<0.05. The conclusion of this study is the Red Fruit Oil could decrease the level of CK at maximum physical activity.

  16. Can origin of the 2400-year cycle of solar activity be caused by solar inertial motion?

    Directory of Open Access Journals (Sweden)

    I. Charvátová

    Full Text Available A solar activity cycle of about 2400 years has until now been of uncertain origin. Recent results indicate it is caused by solar inertial motion. First we describe the 178.7-year basic cycle of solar motion. The longer cycle, over an 8000 year interval, is found to average 2402.2 years. This corresponds to the Jupiter/Heliocentre/Barycentre alignments (9.8855 × 243. Within each cycle an exceptional segment of 370 years has been found characterized by a looping pattern by a trefoil or quasitrefoil geometry. Solar activity, evidenced by 14C tree-ring proxies, shows the same pattern. Solar motion is computable in advance, so this provides a basis for future predictive assessments. The next 370-year segment will occur between AD 2240 and 2610.

    Key words: Solar physics (celestial mechanics

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-10

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  19. Occurrence and zonal drifts of small-scale ionospheric irregularities over an equatorial station during solar maximum - Magnetic quiet and disturbed conditions

    Science.gov (United States)

    Muella, M. T. A. H.; de Paula, E. R.; Kantor, I. J.; Rezende, L. F. C.; Smorigo, P. F.

    2009-06-01

    A statistical study of L-band amplitude scintillations and zonal drift velocity of Fresnel-scale ionospheric irregularities is presented. Ground-based global positioning system (GPS) data acquired at the equatorial station of São Luís (2.33°S, 44.21°W, dip latitude 1.3°S), Brazil, during the solar maximum period from March 2001 to February 2002 are used in the analysis. The variation of scintillations and irregularity drift velocities with local time, season and magnetic activity are reported. The results reveal that for the near overhead ionosphere (satellite elevation angle >45°) a broad maximum in the occurrence of scintillation is seen from October to February. In general, weak scintillations (S 4 90%) during equinox (March-April; September-October) and December solstice (November-February) quiet time conditions and, many of the scintillations, occurred during pre-midnight hours. The mean zonal velocities of the irregularities are seen to be ˜30 m s -1 larger near December solstice, while during the equinoctial period the velocities decay faster and the scintillations tend to cease earlier. On geomagnetically disturbed nights, scintillation activity seems to be strongly affected by the prompt penetration of magnetospheric electric fields and disturbance dynamo effects. On disturbed days, during the equinox and December solstice seasons, the scintillations tend to be suppressed in the pre-midnight hours, whereas during June solstice months (May-August) the effect is opposite. In the post-midnight period, the mostly marked increase in the scintillation occurrence is observed during the equinox months. The results show that during disturbed conditions only one type of storm (when the main phase maximum takes place during the daytime hours) agrees with the Aarons' description, that is the suppression of L-band scintillations in the first recovery phase night. The results also reveal that the storm-time irregularity drifts become more spread in velocity and

  20. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  1. Recent perspectives in solar physics - Elemental composition, coronal structure and magnetic fields, solar activity

    Science.gov (United States)

    Newkirk, G., Jr.

    1975-01-01

    Elemental abundances in the solar corona are studied. Abundances in the corona, solar wind and solar cosmic rays are compared to those in the photosphere. The variation in silicon and iron abundance in the solar wind as compared to helium is studied. The coronal small and large scale structure is investigated, emphasizing magnetic field activity and examining cosmic ray generation mechanisms. The corona is observed in the X-ray and EUV regions. The nature of coronal transients is discussed with emphasis on solar-wind modulation of galactic cosmic rays. A schematic plan view of the interplanetary magnetic field during sunspot minimum is given showing the presence of magnetic bubbles and their concentration in the region around 4-5 AU by a fast solar wind stream.

  2. Solar Radius at Subterahertz Frequencies and Its Relation to Solar Activity

    Science.gov (United States)

    Menezes, Fabian; Valio, Adriana

    2017-12-01

    The Sun emits radiation at several wavelengths of the electromagnetic spectrum. In the optical band, the solar radius is 695 700 km, and this defines the photosphere, which is the visible surface of the Sun. However, as the altitude increases, the electromagnetic radiation is produced at other frequencies, causing the solar radius to change as a function of wavelength. These measurements enable a better understanding of the solar atmosphere, and the radius dependence on the solar cycle is a good indicator of the changes that occur in the atmospheric structure. We measure the solar radius at the subterahertz frequencies of 0.212 and 0.405 THz, which is the altitude at which these emissions are primarily generated, and also analyze the radius variation over the 11-year solar activity cycle. For this, we used radio maps of the solar disk for the period between 1999 and 2017, reconstructed from daily scans made by the Solar Submillimeter-wave Telescope (SST), installed at El Leoncito Astronomical Complex (CASLEO) in the Argentinean Andes. Our measurements yield radii of 966.5'' ±2.8'' for 0.2 THz and 966.5'' ±2.7'' for 0.4 THz. This implies a height of 5.0 ±2.0 ×106 m above the photosphere. Furthermore, we also observed a strong anticorrelation between the radius variation and the solar activity at both frequencies.

  3. The 3-D solar radioastronomy and the structure of the corona and the solar wind. [solar probes of solar activity

    Science.gov (United States)

    Steinberg, J. L.; Caroubalos, C.

    1976-01-01

    The mechanism causing solar radio bursts (1 and 111) is examined. It is proposed that a nonthermal energy source is responsible for the bursts; nonthermal energy is converted into electromagnetic energy. The advantages are examined for an out-of-the-ecliptic solar probe mission, which is proposed as a means of stereoscopically viewing solar radio bursts, solar magnetic fields, coronal structure, and the solar wind.

  4. Study of non-domestic applications for active solar heating

    Energy Technology Data Exchange (ETDEWEB)

    Stammers, J.R.

    1997-11-01

    The UK Department of Trade and Industry (through ETSU) commissioned this study as part of its active solar programme. It was carried out from October 1996 to June 1997. The objective was to assess the potential for the use of active solar heating in non-domestic applications. The study was carried out by searching the literature, carrying out case studies and interviewing members of the solar industry and experts in other fields. There are currently about 45-50 active solar non-domestic schemes in operation in the UK, mostly for heating tap water in buildings of different types. The biggest potential for future non-domestic sales also lies in solar water heating for buildings. Most of the opportunities seem to be in the following building types: ablutions blocks in caravan and holiday camps, sheltered flats and hostels, nursing homes, office buildings, hotels and guest houses, and schools occupied during the summer. There are some other building types which might present niche markets for solar water heating. The market for active solar systems in space heating and cooling appears to be negligible. There is one other market for active solar heating in the non-domestic building sector. This is for warming water used to maintain stand-by generators at a temperature which allows them to kick in without delay in the event of a mains power failure. The main market is in buildings housing computers which control the provision of vital services, e.g. electricity, water and gas. (author)

  5. Statistical Analysis of Solar Events Associated with Storm Sudden Commencements over One Year of Solar Maximum during Cycle 23: Propagation and Effects from the Sun to the Earth.

    Science.gov (United States)

    Bocchialini, K.; Grison, B.; Menvielle, M.; Chambodut, A.; Cornilleau-Wehrlin, N.; Fontaine, D.; Marchaudon, A.; Pick, M.; Pitout, F.; Schmieder, B.; Régnier, S.; Zouganelis, I.

    2017-12-01

    From the list of 32 SSCs over the year 2002, we performed a multi-criteria analysis based on propagation time, velocity comparison, sense of the magnetic field rotation, radio waves to associate them with solar sources, identify their causes in the interplanetary medium and then look at the response of the terrestrial ionized and neutral environment to them. The complex interactions between two (or more) CMEs and the modification in their trajectory have been examined using joint white light and multiple-wavelength radio observations. The structures at L_1 after the 32 SSCs are regarded as Magnetic Clouds (MCs), ICMEs without a MC structure, Miscellaneous structures, CIRs/SIRs, and shock-only events. In terms of geoeffectivity, generally CMEs with velocities at the Sun larger than 1000 km.s-1 have larger probabilities to trigger moderate or intense storms. The most geoeffective events are MCs, since 92% of them trigger moderate or intense storms. The geoeffective events trigger an increased and combined AKR and NTC wave activity in the magnetosphere, an enhanced convection in the ionosphere and a stronger response in the thermosphere.

  6. MAGNETIC ENERGY SPECTRA IN SOLAR ACTIVE REGIONS

    International Nuclear Information System (INIS)

    Abramenko, Valentyna; Yurchyshyn, Vasyl

    2010-01-01

    Line-of-sight magnetograms for 217 active regions (ARs) with different flare rates observed at the solar disk center from 1997 January until 2006 December are utilized to study the turbulence regime and its relationship to flare productivity. Data from the SOHO/MDI instrument recorded in the high-resolution mode and data from the BBSO magnetograph were used. The turbulence regime was probed via magnetic energy spectra and magnetic dissipation spectra. We found steeper energy spectra for ARs with higher flare productivity. We also report that both the power index, α, of the energy spectrum, E(k) ∼ k -α , and the total spectral energy, W = ∫E(k)dk, are comparably correlated with the flare index, A, of an AR. The correlations are found to be stronger than those found between the flare index and the total unsigned flux. The flare index for an AR can be estimated based on measurements of α and W as A = 10 b (αW) c , with b = -7.92 ± 0.58 and c = 1.85 ± 0.13. We found that the regime of the fully developed turbulence occurs in decaying ARs and in emerging ARs (at the very early stage of emergence). Well-developed ARs display underdeveloped turbulence with strong magnetic dissipation at all scales.

  7. Construction of a century solar chromosphere data set for solar activity related research

    Science.gov (United States)

    Lin, Ganghua; Wang, Xiao Fan; Yang, Xiao; Liu, Suo; Zhang, Mei; Wang, Haimin; Liu, Chang; Xu, Yan; Tlatov, Andrey; Demidov, Mihail; Borovik, Aleksandr; Golovko, Aleksey

    2017-06-01

    This article introduces our ongoing project "Construction of a Century Solar Chromosphere Data Set for Solar Activity Related Research". Solar activities are the major sources of space weather that affects human lives. Some of the serious space weather consequences, for instance, include interruption of space communication and navigation, compromising the safety of astronauts and satellites, and damaging power grids. Therefore, the solar activity research has both scientific and social impacts. The major database is built up from digitized and standardized film data obtained by several observatories around the world and covers a time span of more than 100 years. After careful calibration, we will develop feature extraction and data mining tools and provide them together with the comprehensive database for the astronomical community. Our final goal is to address several physical issues: filament behavior in solar cycles, abnormal behavior of solar cycle 24, large-scale solar eruptions, and sympathetic remote brightenings. Significant signs of progress are expected in data mining algorithms and software development, which will benefit the scientific analysis and eventually advance our understanding of solar cycles.

  8. Construction of a century solar chromosphere data set for solar activity related research

    Directory of Open Access Journals (Sweden)

    Ganghua Lin

    2017-06-01

    Full Text Available This article introduces our ongoing project “Construction of a Century Solar Chromosphere Data Set for Solar Activity Related Research”. Solar activities are the major sources of space weather that affects human lives. Some of the serious space weather consequences, for instance, include interruption of space communication and navigation, compromising the safety of astronauts and satellites, and damaging power grids. Therefore, the solar activity research has both scientific and social impacts. The major database is built up from digitized and standardized film data obtained by several observatories around the world and covers a timespan more than 100 years. After careful calibration, we will develop feature extraction and data mining tools and provide them together with the comprehensive database for the astronomical community. Our final goal is to address several physical issues: filament behavior in solar cycles, abnormal behavior of solar cycle 24, large-scale solar eruptions, and sympathetic remote brightenings. Significant progresses are expected in data mining algorithms and software development, which will benefit the scientific analysis and eventually advance our understanding of solar cycles.

  9. The maximum specific hydrogen-producing activity of anaerobic mixed cultures: definition and determination.

    Science.gov (United States)

    Mu, Yang; Yang, Hou-Yun; Wang, Ya-Zhou; He, Chuan-Shu; Zhao, Quan-Bao; Wang, Yi; Yu, Han-Qing

    2014-06-10

    Fermentative hydrogen production from wastes has many advantages compared to various chemical methods. Methodology for characterizing the hydrogen-producing activity of anaerobic mixed cultures is essential for monitoring reactor operation in fermentative hydrogen production, however there is lack of such kind of standardized methodologies. In the present study, a new index, i.e., the maximum specific hydrogen-producing activity (SHAm) of anaerobic mixed cultures, was proposed, and consequently a reliable and simple method, named SHAm test, was developed to determine it. Furthermore, the influences of various parameters on the SHAm value determination of anaerobic mixed cultures were evaluated. Additionally, this SHAm assay was tested for different types of substrates and bacterial inocula. Our results demonstrate that this novel SHAm assay was a rapid, accurate and simple methodology for determining the hydrogen-producing activity of anaerobic mixed cultures. Thus, application of this approach is beneficial to establishing a stable anaerobic hydrogen-producing system.

  10. The maximum specific hydrogen-producing activity of anaerobic mixed cultures: definition and determination

    Science.gov (United States)

    Mu, Yang; Yang, Hou-Yun; Wang, Ya-Zhou; He, Chuan-Shu; Zhao, Quan-Bao; Wang, Yi; Yu, Han-Qing

    2014-06-01

    Fermentative hydrogen production from wastes has many advantages compared to various chemical methods. Methodology for characterizing the hydrogen-producing activity of anaerobic mixed cultures is essential for monitoring reactor operation in fermentative hydrogen production, however there is lack of such kind of standardized methodologies. In the present study, a new index, i.e., the maximum specific hydrogen-producing activity (SHAm) of anaerobic mixed cultures, was proposed, and consequently a reliable and simple method, named SHAm test, was developed to determine it. Furthermore, the influences of various parameters on the SHAm value determination of anaerobic mixed cultures were evaluated. Additionally, this SHAm assay was tested for different types of substrates and bacterial inocula. Our results demonstrate that this novel SHAm assay was a rapid, accurate and simple methodology for determining the hydrogen-producing activity of anaerobic mixed cultures. Thus, application of this approach is beneficial to establishing a stable anaerobic hydrogen-producing system.

  11. X-ray photographs of a solar active region with a multilayer telescope at normal incidence

    Science.gov (United States)

    Underwood, J. H.; Bruner, M. E.; Haisch, B. M.; Brown, W. A.; Acton, L. W.

    1987-01-01

    An astronomical photograph was obtained with a multilayer X-ray telescope. A 4-cm tungsten-carbon multilayer mirror was flown as part of an experimental solar rocket payload, and successful images were taken of the sun at normal incidence at a wavelength of 44 A. Coronal Si XII emission from an active region was recorded on film; as expected, the structure is very similar to that observed at O VIII wavelengths by the Solar Maximum Mission flat-crystal spectrometer at the same time. The small, simple optical system used in this experiment appears to have achieved a resolution of 5 to 10 arcsec.

  12. Enerplan, Professional association of solar energy - activity report 2007. Network of solar energy professionals in France

    International Nuclear Information System (INIS)

    2008-01-01

    Enerplan is the French union of solar energy professionals. Created in 1983, its social purpose is the study and defense of the rights and of the material and moral interests of its members. Enerplan structures its action through two poles representing members' activities: 'solar energy and building' where topics about heat and electricity generation in relation with buildings are treated, and 'photovoltaic energy' where topics specific to big solar power plants are considered. Thanks to the collaborative participation of its members, both poles allow Enerplan union to be source of proposals to develop solar energy in France. As an active interface between professionals and institutions, Enerplan includes in its membership: industrialists, plant makers, engineering consultants, installers, associations, energy suppliers etc, from small-medium size companies to big groups. This document presents Enerplan's activities in 2007 (public relations, lobbying, meetings and conferences, promotional activities, collaborations, projects..)

  13. Enerplan, Professional association of solar energy - activity report 2008. Acting for solar energy promotion and development

    International Nuclear Information System (INIS)

    2009-01-01

    Enerplan is the French union of solar energy professionals. Created in 1983, its social purpose is the study and defense of the rights and of the material and moral interests of its members. Enerplan structures its action through two poles representing members' activities: 'solar energy and building' where topics about heat and electricity generation in relation with buildings are treated, and 'photovoltaic energy' where topics specific to big solar power plants are considered. Thanks to the collaborative participation of its members, both poles allow Enerplan union to be source of proposals to develop solar energy in France. As an active interface between professionals and institutions, Enerplan includes in its membership: industrialists, plant makers, engineering consultants, installers, associations, energy suppliers etc, from small-medium size companies to big groups. This document presents Enerplan's activities in 2008 (public relations, lobbying, meetings and conferences, promotional activities, collaborations, projects..)

  14. Solar energy activities in the Arab countries

    International Nuclear Information System (INIS)

    Sayigh, A.A.M.

    1991-01-01

    The Arab countries, 22 in total, are divided into three groups. Group one consists of all countries of the Middle East. The second group is the Arabian Peninsula, and the third group consists of all Arab countries in Africa. The paper outlines the solar density and sunshine hours, as well as wind data in the region and compares them with some industrialized countries. Brief surveys of various solar energy projects are tabulated: that is solar, wind and biomass. Several specific major projects in various parts of the Arab World will be discussed. More specifically, the cooling of the solar energy research building in Baghdad (120 tons of solar absorption chillers, 80 tons of heat pumps), the heating of King Abdu-Asis Airborne and Physical Training School near Tabuk, Saudi Arabia, the 350 kW PV. field of the solar energy village near Riyadh and the 100 kW solar thermal plant in Kuwait are discussed. It is worth noting that the present photovoltaic capacity in the Arab world is more than 3.0 MW and the yearly installation potential per year is 2.0 MW. There are at least five photovoltaic production facilities in the Arab countries. Two of them in Saudi Arabia with capacity of 400 kW, one in Iraq with a capacity of 200 kW, one in Tunisia with a capacity of 100 kW and on in Algeria with capacity of 100 kW. The Arab countries can absorb 5MW per year and more countries like Egypt, Sudan, Morocco, Jordan and Libya are thinking of having their own production capabilities. Five desalination plants are also mentioned, plus the Yanbu plant of 240m/day, which is one of the largest in the world. The potential of wind energy utilisation is considered. Obstacles hindering the process of solar energy in the region are also outlined. (author). 11 refs, 1 fig., 4 tabs

  15. The effects of changing solar activity on climate: contributions from palaeoclimatological studies

    Directory of Open Access Journals (Sweden)

    Engels Stefan

    2012-07-01

    Full Text Available Natural climate change currently acts in concert with human-induced changes in the climate system. To disentangle the natural variability in the climate system and the human-induced effects on the global climate, a critical analysis of climate change in the past may offer a better understanding of the processes that drive the global climate system. In this review paper, we present palaeoclimatological evidence for the past influence of solar variability on Earth’s climate, highlighting the effects of solar forcing on a range of timescales. On a decadal timescale, instrumental measurements as well as historical records show the effects of the 11-year Schwabe cycle on climate. The variation in total solar irradiance that is associated with a Schwabe cycle is only ~1 W m−2 between a solar minimum and a maximum, but winter and spring temperatures on the Northern Hemisphere show a response even to this small-scale variability. There is a large body of evidence from palaeoclimatic reconstructions that shows the influence of solar activity on a centennial to millennial timescale. We highlight a period of low solar activity starting at 2800 years before present when Europe experienced a shift to colder and wetter climate conditions. The spatial pattern of climate change that can be recognized in the palaeoclimatological data is in line with the suggested pattern of climate change as simulated by climate models. Millennial-scale climate oscillations can be recognized in sediment records from the Atlantic Ocean as well as in records of lake-level fluctuations in southeastern France. These oscillations coincide with variation in 14C production as recognized in the atmospheric 14C record (which is a proxy-record for solar activity, suggesting that Earth’s climate is sensitive to changes in solar activity on a millennial timescale as well.

  16. Study of an active wall solar heating system

    International Nuclear Information System (INIS)

    Kassem, Talal

    2006-01-01

    An active wall solar heating system was built and tested. In the same time a compatible computer program has been according to set the recommended dimensions for the solar collectors where (F-Chart) method used to set the ratio of monthly solar sharing average for the examined heating system. Some parameters, such as collectors' areas, its tilt angle and near earth reflecting were experimentally investigated, affecting the executed active solar heating system performance. The study explain the ability of using this system which is simple, Low coast and high performance in heating residential and public buildings and heating water with ratio of yearly solar sharing achieves the needed saving of using this system.(Author)

  17. The relationship between solar activity and the H and K line cores in integrated sunlight

    International Nuclear Information System (INIS)

    Jebsen, D.E.; Mitchell, W.E. Jr.

    1978-01-01

    In this paper the authors present and analyze new data on the cores of the H and K lines of ionized calcium in the spectrum of integrated sunlight. The intensities of the components Hsub(2γ), H 3 , Hsub(2r), Ksub(2γ), K 3 , and Ksub(2r) in the line cores were measured in terms of the continuum intensity at 4000 A during a solar rotation in September 1969. Other data on these components, obtained at or close to the time of solar minimum (September 1964) and solar maximum (September 1968), were also included. The intensities of these features are compared with two indices of solar activity: the Ca II plage index and the 2800 MHZ signal. The average correlation coefficients between the intensities of the measured features and those indices were 0.69 and 0.64, respectively. The results are consistent with those of Bumba and Ruzickova-Topolova (1967) for a solar rotation period in 1965. The method and results should provide a detailed quantitative basis for the study of the activity cycles and rotation periods of solar-type stars. (Auth.)

  18. Variability of the Lyman alpha flux with solar activity

    International Nuclear Information System (INIS)

    Lean, J.L.; Skumanich, A.

    1983-01-01

    A three-component model of the solar chromosphere, developed from ground based observations of the Ca II K chromospheric emission, is used to calculate the variability of the Lyman alpha flux between 1969 and 1980. The Lyman alpha flux at solar minimum is required in the model and is taken as 2.32 x 10 11 photons/cm 2 /s. This value occurred during 1975 as well as in 1976 near the commencement of solar cycle 21. The model predicts that the Lyman alpha flux increases to as much as 5 x 10 11 photons/cm 2 /s at the maximum of the solar cycle. The ratio of the average fluxes for December 1979 (cycle maximum) and July 1976 (cycle minimum) is 1.9. During solar maximum the 27-day solar rotation is shown to cause the Lyman alpha flux to vary by as much as 40% or as little as 5%. The model also shows that the Lyman alpha flux varies over intermediate time periods of 2 to 3 years, as well as over the 11-year sunspot cycle. We conclude that, unlike the sunspot number and the 10.7-cm radio flux, the Lyman alpha flux had a variability that was approximately the same during each of the past three cycles. Lyman alpha fluxes calculated by the model are consistent with measurements of the Lyman alpha flux made by 11 of a total of 14 rocket experiments conducted during the period 1969--1980. The model explains satisfactorily the absolute magnitude, long-term trends, and the cycle variability seen in the Lyman alpha irradiances by the OSO 5 satellite experiment. The 27-day variability observed by the AE-E satellite experiment is well reproduced. However, the magntidue of the AE-E 1 Lyman alpha irradiances are higher than the model calculations by between 40% and 80%. We suggest that the assumed calibration of the AE-E irradiances is in error

  19. Enerplan, Professional association of solar energy - activity report 2006

    International Nuclear Information System (INIS)

    2007-01-01

    Enerplan is the French union of solar energy professionals. Created in 1983, its social purpose is the study and defense of the rights and of the material and moral interests of its members. Enerplan structures its action through two poles representing members' activities: 'solar energy and building' where topics about heat and electricity generation in relation with buildings are treated, and 'photovoltaic energy' where topics specific to big solar power plants are considered. Thanks to the collaborative participation of its members, both poles allow Enerplan union to be source of proposals to develop solar energy in France. As an active interface between professionals and institutions, Enerplan includes in its membership: industrialists, plant makers, engineering consultants, installers, associations, energy suppliers etc, from small-medium size companies to big groups. This document presents Enerplan's activities in 2006 (public relations, lobbying, meetings and conferences, promotional activities, collaborations, projects..)

  20. Indexes and parameters of activity in solar-terrestrial physics

    International Nuclear Information System (INIS)

    Minasyants, G.S.; Minasyants, T.M.

    2005-01-01

    The daily variation of different indexes and parameters of the solar-terrestrial physics at the 23 cycle were considered to find the most important from them for the forecast of geomagnetic activity. The validity of application of the Wolf numbers in quality of the characteristic of solar activity at sunspots is confirmed. The best geo-effective parameter in the arrival of the interplanetary shock from coronal mass ejection to an orbit of the Earth. (author)

  1. Solar activity and life. A review

    International Nuclear Information System (INIS)

    Messerotti, M.; Chela-Flores, J.

    2007-09-01

    Recent claims advocate a downward revision of the solar oxygen abundance. This is a reflection of what may be called a 'solar crisis' whereby we mean that previous consensus in our understanding of our nearest star was unfounded. The implications for solar physics, and chemistry, are obvious and much research in the near future will give us a much clearer understanding of the Sun. We wish to review and update recent work concerning the frontier between Space Weather (SpW) and Astrobiology. We argue that the present robust programs of various space agencies reinforce our hope for a better understanding of the bases of Astrobiology. Eventually with a more realistic model of the Sun, more reliable discussions of all the factors influencing the origin of life on Earth will be possible. (author)

  2. Conceptual model to determine maximum activity of radioactive waste in near-surface disposal facilities

    International Nuclear Information System (INIS)

    Iarmosh, I.; Olkhovyk, Yu.

    2016-01-01

    For development of the management strategy for radioactive waste to be placed in near - surface disposal facilities (NSDF), it is necessary to justify long - term safety of such facilities. Use of mathematical modelling methods for long - term forecasts of radwaste radiation impact and assessment of radiation risks from radionuclides migration can help to resolve this issue. The purpose of the research was to develop the conceptual model for determining the maximum activity of radwaste to be safely disposed in the NSDF and to test it in the case of Lot 3 Vector NSDF (Chornobyl exclusion zone). This paper describes an approach to the development of such a model. The conceptual model of "9"0 Sr migration from Lot 3 through aeration zone and aquifer soils was developed. The results of modelling are shown. The proposals on further steps for the model improvement were developed

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

    Directory of Open Access Journals (Sweden)

    P. T. Gallagher

    2002-07-01

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

  4. Active solar heating and cooling information user study

    Energy Technology Data Exchange (ETDEWEB)

    Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

    1981-01-01

    The results of a series of telephone interviews with groups of users of information on active solar heating and cooling (SHAC). An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from 19 SHAC groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Manufacturers (4 groups), Distributors, Installers, Architects, Builders, Planners, Engineers (2 groups), Representatives of Utilities, Educators, Cooperative Extension Service County Agents, Building Owners/Managers, and Homeowners (2 groups). The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

  5. Solar activity affects avian timing of reproduction

    NARCIS (Netherlands)

    Visser, M.E.; Sanz, J.J.

    2009-01-01

    Avian timing of reproduction is strongly affected by ambient temperature. Here we show that there is an additional effect of sunspots on laying date, from five long-term population studies of great and blue tits (Parus major and Cyanistes caeruleus), demonstrating for the first time that solar

  6. Are cold winters in Europe associated with low solar activity?

    International Nuclear Information System (INIS)

    Lockwood, M; Harrison, R G; Woollings, T; Solanki, S K

    2010-01-01

    Solar activity during the current sunspot minimum has fallen to levels unknown since the start of the 20th century. The Maunder minimum (about 1650-1700) was a prolonged episode of low solar activity which coincided with more severe winters in the United Kingdom and continental Europe. Motivated by recent relatively cold winters in the UK, we investigate the possible connection with solar activity. We identify regionally anomalous cold winters by detrending the Central England temperature (CET) record using reconstructions of the northern hemisphere mean temperature. We show that cold winter excursions from the hemispheric trend occur more commonly in the UK during low solar activity, consistent with the solar influence on the occurrence of persistent blocking events in the eastern Atlantic. We stress that this is a regional and seasonal effect relating to European winters and not a global effect. Average solar activity has declined rapidly since 1985 and cosmogenic isotopes suggest an 8% chance of a return to Maunder minimum conditions within the next 50 years (Lockwood 2010 Proc. R. Soc. A 466 303-29): the results presented here indicate that, despite hemispheric warming, the UK and Europe could experience more cold winters than during recent decades.

  7. A comparison of muscle activity in concentric and counter movement maximum bench press.

    Science.gov (United States)

    van den Tillaar, Roland; Ettema, Gertjan

    2013-01-01

    The purpose of this study was to compare the kinematics and muscle activation patterns of regular free-weight bench press (counter movement) with pure concentric lifts in the ascending phase of a successful one repetition maximum (1-RM) attempt in the bench press. Our aim was to evaluate if diminishing potentiation could be the cause of the sticking region. Since diminishing potentiation cannot occur in pure concentric lifts, the occurrence of a sticking region in this type of muscle actions would support the hypothesis that the sticking region is due to a poor mechanical position. Eleven male participants (age 21.9 ± 1.7 yrs, body mass 80.7 ± 10.9 kg, body height 1.79 ± 0.07 m) conducted 1-RM lifts in counter movement and in pure concentric bench presses in which kinematics and EMG activity were measured. In both conditions, a sticking region occurred. However, the start of the sticking region was different between the two bench presses. In addition, in four of six muscles, the muscle activity was higher in the counter movement bench press compared to the concentric one. Considering the findings of the muscle activity of six muscles during the maximal lifts it was concluded that the diminishing effect of force potentiation, which occurs in the counter movement bench press, in combination with a delayed muscle activation unlikely explains the existence of the sticking region in a 1-RM bench press. Most likely, the sticking region is the result of a poor mechanical force position.

  8. Analysis of selected microflares observed by SphinX over the last minimum of solar activity

    Science.gov (United States)

    Siarkowski, Marek; Sylwester, Janusz; Sylwester, Barbara; Gryciuk, Magdalena

    The Solar Photometer in X-rays (SphinX) was designed to observe soft X-ray solar emission in the energy range between 1 keV and 15 keV with the resolution better than 0.5 keV. The instrument operated from February until November 2009 aboard CORONAS-Photon satellite, during the phase of exceptionally low minimum of solar activity. Here we use SphinX data for analysis of selected microflare-class events. We selected events of unusual lightcurves or location. Our study involves determination of temporal characteristics (times of start, maximum and end of flares) and analysis of physical conditions in flaring plasma (temperature, emission measure). Dedicated method has been used in order to remove emission not related to flare. Supplementary information about morphology and evolution of investigated events has been derived from the analysis of XRT/Hinode and SECCHI /STEREO images.

  9. On proton events of different solar activity cycles

    International Nuclear Information System (INIS)

    Sattarov, I.; Sherdanov, Ch.; Sattarov, B.

    1997-01-01

    In solar activity cycle N21 and N22 the latitude distribution of the proton large flares and sunspot groups is being studied. It was found that higher proton activity of cycle N22 is connected with its higher latitude sunspot activity (author)

  10. Twist of Magnetic Fields in Solar Active Regions Hongqi Zhang ...

    Indian Academy of Sciences (India)

    tribpo

    in active regions also shows the butterfly pattern through the solar cycle. And, less than 30% of the active regions do not follow the general trend (Zhang & Bao 1998). The longitudinal distribution of current helicity parameter h|| of active regions in both the hemispheres in the last decade was presented by Zhang & Bao ...

  11. Danish participation in the IEA solar cell activities

    International Nuclear Information System (INIS)

    1994-05-01

    In the 12-month period 01.05.93 - 30.04.94 the Danish activities in the IEA 'Solar Cell Agreement' consisted in: participation in the Executive Committee (ExCo) and participation in Task 1 'Exchange and Dissemination of Information on PV Power Systems'. ExCo has meetings every half-year and is a coordinating organ for the Agreement. Work on the Task 1 is organized in 4 subtasks: (1) mapping of solar cell activities in the OECD countries and preparation of an IEA handbook on solar cell technology; (2) publishing of a semiannual newsletter about the agreement; (3) an 'executive conference' on solar cell technology and its uses with participation of the decision-makers in respective power industries; (4) information dissemination whenever required. Demonstration projects, like a photovoltaic roof-integrated system connected to the grid. have been implemented. Three larger solar cell projects, subsidized by the EU means, comprehend 'real time monitoring' by a solar system, WHO project 'Solar Energy Applications for Primary Health Care Clinics for Remote Rural Areas' (SAPHIR) and a grid-connected photovoltaic system in a suburb residential settlement. (EG)

  12. Global Distribution and Variations of NO Infrared Radiative Flux and Its Responses to Solar Activity and Geomagnetic Activity in the Thermosphere

    Science.gov (United States)

    Tang, Chaoli; Wei, Yuanyuan; Liu, Dong; Luo, Tao; Dai, Congming; Wei, Heli

    2017-12-01

    The global distribution and variations of NO infrared radiative flux (NO-IRF) are presented during 2002-2016 in the thermosphere covering 100-280 km altitude based on Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) data set. For investigating the spatial variations of the mutual relationship between NO-IRF and solar activity, the altitude ranges from 100 km to 280 km are divided into 90 altitude bins, and the latitude regions of 83°S-83°N are divided into 16 latitude bins. By processing about 1.8E9 NO-IRF observation values from about 5E6 vertical nighttime profiles recorded in SABER data set, we obtained more than 4.1E8 samples of NO-IRF. The annual-mean values of NO-IRF are then calculated by all available NO-IRF samples within each latitude and altitude bin. Local latitudinal maxima in NO-IRF are found between 120 and 145 km altitude, and the maximum NO-IRF located at polar regions are 3 times more than that of the minimum at equatorial region. The influences of solar and geomagnetic activity on the spatial variations of NO-IRF are investigated. Both the NO-IRF and its response to solar and geomagnetic activity show nearly symmetric distribution between the two hemispheres. It is demonstrated that the observed changes in NO-IRF at altitudes between 100 and 225 km correlate well with the changes in solar activity. The NO-IRF at solar maximum is about 4 times than that at solar minimum, and the current maximum of NO-IRF in 2014 is less than 70% of the prior maximum in 2001. For the first time, the response ranges of the NO-IRF to solar and geomagnetic activity at different altitudes and latitudes are reported.

  13. Good planning for maximum efficiency. Part 1. Housing development of passive buildings with solar district heat supply; Sauber geplant is halb gewonnen. Teil 1. Passivhaussiedlung mit solarer Nahwaermeversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, R. [Ritter Energie- und Umwelttechnik, Karlsbad (Germany)

    2003-06-01

    A new development of 12 single-family dwellings was constructed with complex technical facilities and many innovative elements by Gewerbepark Ritter and Messrs. Paradigma, a provider of thermal solar systems. [German] Der Gewerbepark Ritter und die auf thermische Solarindustrie spezialisierte Firma Paradigma haben bei der Errichtung einer Siedlung mit 12 Einfamilienhaeusern mit einem komplexen Haustechnikkonzept ein wegweisendes Projekt mit vielen innovativen Neuerungen erfolgreich in die Tat umgesetzt. (orig.)

  14. Ionospheric disturbances under low solar activity conditions

    Czech Academy of Sciences Publication Activity Database

    Burešová, Dalia; Laštovička, Jan; Hejda, Pavel; Bochníček, Josef

    2014-01-01

    Roč. 54, č. 2 (2014), s. 185-196 ISSN 0273-1177 R&D Projects: GA ČR(CZ) GAP209/11/1908 Institutional support: RVO:68378289 ; RVO:67985530 Keywords : ionosphere * solar minimum * magnetic storm s * ionospheric variability Subject RIV: DG - Athmosphere Sciences, Meteorology; DG - Athmosphere Sciences, Meteorology (GFU-E) Impact factor: 1.358, year: 2014 http://www.sciencedirect.com/science/article/pii/S027311771400221X

  15. EQPlanar: a maximum-likelihood method for accurate organ activity estimation from whole body planar projections

    International Nuclear Information System (INIS)

    Song, N; Frey, E C; He, B; Wahl, R L

    2011-01-01

    Optimizing targeted radionuclide therapy requires patient-specific estimation of organ doses. The organ doses are estimated from quantitative nuclear medicine imaging studies, many of which involve planar whole body scans. We have previously developed the quantitative planar (QPlanar) processing method and demonstrated its ability to provide more accurate activity estimates than conventional geometric-mean-based planar (CPlanar) processing methods using physical phantom and simulation studies. The QPlanar method uses the maximum likelihood-expectation maximization algorithm, 3D organ volume of interests (VOIs), and rigorous models of physical image degrading factors to estimate organ activities. However, the QPlanar method requires alignment between the 3D organ VOIs and the 2D planar projections and assumes uniform activity distribution in each VOI. This makes application to patients challenging. As a result, in this paper we propose an extended QPlanar (EQPlanar) method that provides independent-organ rigid registration and includes multiple background regions. We have validated this method using both Monte Carlo simulation and patient data. In the simulation study, we evaluated the precision and accuracy of the method in comparison to the original QPlanar method. For the patient studies, we compared organ activity estimates at 24 h after injection with those from conventional geometric mean-based planar quantification using a 24 h post-injection quantitative SPECT reconstruction as the gold standard. We also compared the goodness of fit of the measured and estimated projections obtained from the EQPlanar method to those from the original method at four other time points where gold standard data were not available. In the simulation study, more accurate activity estimates were provided by the EQPlanar method for all the organs at all the time points compared with the QPlanar method. Based on the patient data, we concluded that the EQPlanar method provided a

  16. Solar-Type Activity in Main-Sequence Stars

    CERN Document Server

    Gershberg, Roald E

    2005-01-01

    Solar-type activity over the whole range of the electromagnetic spectrum is a phenomenon inherent in the majority of low- and moderate-mass main sequence stars. In this monograph observational results are summarized in a systematic and comprehensive fashion. The analysis of the various manifestations of such stellar activity leads to the identification of these phenomena with macroscopic non-linear processes in a magnetized plasma. Comparative study of flare stars and the Sun has become increasingly fruitful and is presently an active field of research involving stellar and solar physicists, experts in plasma physics and high-energy astrophysicists. This book will provide them with both an introduction and overview of observational results from the first optical photometry and spectroscopy, from the satellite telescopes International Ultraviolet Explorer to Hubble Space Telescope, XMM-Newton and Chandra, as well as with the present physical interpretation of solar-type activity in main sequence stars. Gershbe...

  17. Experimental evaluation of an active solar thermoelectric radiant wall system

    International Nuclear Information System (INIS)

    Liu, ZhongBing; Zhang, Ling; Gong, GuangCai; Han, TianHe

    2015-01-01

    Highlights: • A novel active solar thermoelectric radiant wall are proposed and tested. • The novel wall can control thermal flux of building envelope by using solar energy. • The novel wall can eliminate building envelop thermal loads and provide cooling capacity for space cooling. • Typical application issues including connection strategies, coupling with PV system etc. are discussed. - Abstract: Active solar thermoelectric radiant wall (ASTRW) system is a new solar wall technology which integrates thermoelectric radiant cooling and photovoltaic (PV) technologies. In ASTRW system, a PV system transfers solar energy directly into electrical energy to power thermoelectric cooling modes. Both the thermoelectric cooling modes and PV system are integrated into one enclosure surface as radiant panel for space cooling and heating. Hence, ASTRW system presents fundamental shift from minimizing building envelope energy losses by optimizing the insulation thickness to a new regime where active solar envelop is designed to eliminate thermal loads and increase the building’s solar gains while providing occupant comfort in all seasons. This article presents an experimental study of an ASTRW system with a dimension of 1580 × 810 mm. Experimental results showed that the inner surface temperature of the ASTRW is 3–8 °C lower than the indoor temperature of the test room, which indicated that the ASTRW system has the ability to control thermal flux of building envelope by using solar energy and reduce the air conditioning system requirements. Based on the optimal operating current of TE modules and the analysis based upon PV modeling theories, the number and type of the electrical connections for the TE modules in ASTRW system are discussed in order to get an excellent performance in the operation of the ASTRW system

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  19. Solar collector wall with active curtain system; Lasikatteinen massiivienen aurinkokeraeaejaeseinae

    Energy Technology Data Exchange (ETDEWEB)

    Ojanen, T.; Heimonen, I. [VTT Building Technology, Espoo (Finland). Building Physics, Building Services and Fire Technology

    1998-12-01

    Integration of solar collector into the building envelope structure brings many advantages. The disadvantage of a passive solar collector wall is that its thermal performance can not be controlled, which may cause temporary overheating and low thermal efficiency of the collector. The thermal performance of the collector wall can be improved by using controllable, active collector systems. In this paper a solar collector wall with a controllable curtain between the transparent and absorption layers is investigated. The curtain is made of several low-emissivity foil layers, which ensures low radiation heat transfer through the curtain. The curtain decreases the heat losses out from the collector wall and it improves the U-value of the wall. The curtain is used when the solar radiation intensity to the wall is not high enough or when the wall needs protection against overheating during warm weather conditions. The materials and building components used in the collector wall, except those of the curtain, are ordinary in buildings. The transparent layer can be made by using normal glazing technology and the thermal storage layer can be made out of brick or similar material. The solar energy gains through the glazing can be utilised better than in passive systems, because the curtain provides the wall with high thermal resistance outside the solar radiation periods. The thermal performance of the collector wall was studied experimentally using a Hot-Box apparatus equipped with a solar lamp. Numerical simulations were carried out to study the yearly performance of the collector wall under real climate conditions. The objectives were to determine the thermal performance of the collector wall and to study how to optimise the use of solar radiation in this system. When the curtain with high thermal resistance is used actively, the temperature level of the thermal storage layer in the wall is relatively high also during dark periods and the heat losses out from the storage

  20. Initiation of non-tropical thunderstorms by solar activity

    Energy Technology Data Exchange (ETDEWEB)

    Herman, J R [Radio Sciences Co., Melbourne, Fla. (USA); Goldberg, R A

    1978-02-01

    Correlative evidence accumulating since 1926 suggests that there must be some physical coupling mechanism between solar activity and thunderstorm occurrence in middle to high latitudes. Such a link may be provided by alteration of atmospheric electric parameters through the influence of cosmic ray decreases and/or high-energy solar protons associated with active solar events. Galactic cosmic ray decreases tend to enhance the electric field at low heights. The protons produce excess ionization near and above 20 km, greatly increasing the atmospheric conductivity and possibly lowering the height of the electrosphere. Consequent effects near the solar proton cut-off latitude also lead to an enhancement of the atmospheric electric field near the surface. If appropriate meteorological conditions (warm moist air with updrafts) exist or develop during a solar event, the atmospheric electric field enhancement may be sufficient to trigger thunderstorm development. The suggested mechanism appears plausible enough to warrant a co-ordinated experimental effort involving satellite balloon and ground-based measurements of the possible forcing functions (solar protons and cosmic rays) and the responding atmospheric electrical and ionic species' characteristics.

  1. Solar Cell Polymer Based Active Ingredients PPV and PCBM

    Science.gov (United States)

    Hardeli, H.; Sanjaya, H.; Resikarnila, R.; Nitami H, R.

    2018-04-01

    A polymer solar cell is a solar cell based on a polymer bulk heterojunction structure using the method of thin film, which can convert solar energy into electrical energy. Absorption of light is carried by active material layer PPV: PCBM. This study aims to make solar cells tandem and know the value of converting solar energy into electrical energy and increase the value of efficiency generated through morphological control, ie annealing temperature and the ratio of active layer mixture. The active layer is positioned above the PEDOT:PSS layer on ITO glass substrate. The characterization results show the surface morphology of the PPV:PCBM active layer is quite evenly at annealing temperature of 165 ° C. The result of conversion of electrical energy with a UV light source in annealing samples with temperature 165 ° C is 0.03 mA and voltage of 4.085 V with an efficiency of 2.61% and mixed ratio variation was obtained in comparison of P3HT: PCBM is 1: 3

  2. Integrated solar thermal Brayton cycles with either one or two regenerative heat exchangers for maximum power output

    International Nuclear Information System (INIS)

    Jansen, E.; Bello-Ochende, T.; Meyer, J.P.

    2015-01-01

    The main objective of this paper is to optimise the open-air solar-thermal Brayton cycle by considering the implementation of the second law of thermodynamics and how it relates to the design of the heat exchanging components within it. These components included one or more regenerators (in the form of cross-flow heat exchangers) and the receiver of a parabolic dish concentrator where the system heat was absorbed. The generation of entropy was considered as it was associated with the destruction of exergy or available work. The dimensions of some components were used to optimise the cycles under investigation. EGM (Entropy Generation Minimisation) was employed to optimise the system parameters by considering their influence on the total generation of entropy (destruction of exergy). Various assumptions and constraints were considered and discussed. The total entropy generation rate and irreversibilities were determined by considering the individual components and ducts of the system, as well as their respective inlet and outlet conditions. The major system parameters were evaluated as functions of the mass flow rate to allow for a proper discussion of the system performance. The performances of both systems were investigated, and characteristics were listed for both. Finally, a comparison is made to shed light on the differences in performance. - Highlights: • Implementation of the second law of thermodynamics. • Design of heat exchanging and collecting equipment. • Utilisation of Entropy Generation Minimization. • Presentation of a multi-objective optimization. • Raise efficiency with more regeneration

  3. Effects of Solar Activity and Space Environment in 2003 Oct.

    Directory of Open Access Journals (Sweden)

    Kyung-Seok Cho

    2004-12-01

    Full Text Available In this paper, we present a good example of extreme solar and geomagnetic activities from October to November, 2003. These activities are characterized by very large sunspot groups, X-class solar flares, strong particle events, and huge geomagnetic storms. We discuss ground-based and space-based data in terms of space weather scales. Especially, we present several solar and geomagnetic disturbance data produced in Korea : sunspots, geo-magnetograms, aurora, Ionogram, and Total Electron Content (TEC map by GPS data. Finally, we introduce some examples of the satellite orbit and communication effects caused by these activities; e.g., the disturbances of the KOMPSAT-1 operational orbit and HF communication.

  4. A Maximum Power Point Tracking Control Method of a Photovoltaic Power Generator with Consideration of Dynamic Characteristics of Solar Cells

    Science.gov (United States)

    Watanabe, Takashi; Yoshida, Toshiya; Ohniwa, Katsumi

    This paper discusses a new control strategy for photovoltaic power generation systems with consideration of dynamic characteristics of the photovoltaic cells. The controller estimates internal currents of an equivalent circuit for the cells. This estimated, or the virtual current and the actual voltage of the cells are fed to a conventional Maximum-Power-Point-Tracking (MPPT) controller. Consequently, this MPPT controller still tracks the optimum point even though it is so designed that the seeking speed of the operating point is extremely high. This system may suit for applications, which are installed in rapidly changeable insolation and temperature-conditions e.g. automobiles, trains, and airplanes. The proposed method is verified by experiment with a combination of this estimating function and the modified Boehringer's MPPT algorithm.

  5. The influence of solar active region evolution on solar wind streams, coronal hole boundaries and geomagnetic storms

    International Nuclear Information System (INIS)

    Gold, R.E.; Dodson-Prince, H.W.; Hedeman, E.R.; Roelof, E.C.

    1982-01-01

    We have studied solar and interplanetary data by identification of the heliographic longitudes of the coronal source regions of high speed solar wind streams and by mapping the velocities measured near earth back to the sun using the approximation of constant radial velocity. Interplay of active regions and solar wind were studied

  6. Enhanced photocurrent density in graphene/Si based solar cell (GSSC) by optimizing active layer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Rosikhin, Ahmad, E-mail: a.rosikhin86@yahoo.co.id; Hidayat, Aulia Fikri; Syuhada, Ibnu; Winata, Toto, E-mail: toto@fi.itb.ac.id [Department of physics, physics of electronic materials research division Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Jl. Ganesha 10, Bandung 40132, Jawa Barat – Indonesia (Indonesia)

    2015-12-29

    Thickness dependent photocurrent density in active layer of graphene/Si based solar cell has been investigated via analytical – simulation study. This report is a preliminary comparison of experimental and analytical investigation of graphene/Si based solar cell. Graphene sheet was interfaced with Si thin film forming heterojunction solar cell that was treated as a device model for photocurrent generator. Such current can be enhanced by optimizing active layer thickness and involving metal oxide as supporting layer to shift photons absorption. In this case there are two type of devices model with and without TiO{sub 2} in which the silicon thickness varied at 20 – 100 nm. All of them have examined and also compared with each other to obtain an optimum value. From this calculation it found that generated currents almost linear with thickness but there are saturated conditions that no more enhancements will be achieved. Furthermore TiO{sub 2} layer is effectively increases photon absorption but reducing device stability, maximum current is fluctuates enough. This may caused by the disturbance of excitons diffusion and resistivity inside each layer. Finally by controlling active layer thickness, it is quite useful to estimate optimization in order to develop the next solar cell devices.

  7. Enhanced photocurrent density in graphene/Si based solar cell (GSSC) by optimizing active layer thickness

    International Nuclear Information System (INIS)

    Rosikhin, Ahmad; Hidayat, Aulia Fikri; Syuhada, Ibnu; Winata, Toto

    2015-01-01

    Thickness dependent photocurrent density in active layer of graphene/Si based solar cell has been investigated via analytical – simulation study. This report is a preliminary comparison of experimental and analytical investigation of graphene/Si based solar cell. Graphene sheet was interfaced with Si thin film forming heterojunction solar cell that was treated as a device model for photocurrent generator. Such current can be enhanced by optimizing active layer thickness and involving metal oxide as supporting layer to shift photons absorption. In this case there are two type of devices model with and without TiO 2 in which the silicon thickness varied at 20 – 100 nm. All of them have examined and also compared with each other to obtain an optimum value. From this calculation it found that generated currents almost linear with thickness but there are saturated conditions that no more enhancements will be achieved. Furthermore TiO 2 layer is effectively increases photon absorption but reducing device stability, maximum current is fluctuates enough. This may caused by the disturbance of excitons diffusion and resistivity inside each layer. Finally by controlling active layer thickness, it is quite useful to estimate optimization in order to develop the next solar cell devices

  8. Electrically active defects in solar grade multicrystalline silicon

    DEFF Research Database (Denmark)

    Dahl, Espen

    2013-01-01

    Shortage in high purity silicon feedstock, as a result of the formidable increased demand for solar cell devices during the last two decades, can be mitigated by the introduction of cheaper feedstock of solar grade (So-G) quality. Silicon produced through the metallurgical process route has shown...... the potential to be such a feedstock. However, this feedstock has only few years of active commercial history and the detailed understanding of the nature of structural defects in this material still has fundamental shortcomings. In this thesis the electrical activity of structural defects, commonly associated...

  9. Magnetic activity effect on equatorial spread-F under high and low solar activity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Subbarao, K S.V.; Somayajulu, V V; Krishna Murthy, B V

    1986-08-01

    The effect of magnetic activity on spread-F at two equatorial stations, Trivandrum and Huancayo, separated in longitude by about 150 deg, under high and low solar activity conditions has been investigated. Magnetic activity produces strong inhibition effect on spread-F at Huancayo compared to that at Trivandrum especially during high solar activity period. This results in a decrease of spread-F with solar activity at Huancayo in contrast to Trivandrum. These findings are explained in terms of F-region electrodynamics and Rayleigh-Taylor instability mechanism for spread-F.

  10. Active control of the Chinese Giant Solar Telescope

    Science.gov (United States)

    Dai, Yichun; Yang, Dehua; Jin, Zhenyu; Liu, Zhong; Qin, Wei

    2014-07-01

    The Chinese Giant Solar Telescope (CGST) is the next generation solar telescope of China with diameter of 8 meter. The unique feature of CGST is that its primary is a ring, which facilitates the polarization detection and thermal control. In its present design and development phase, two primary mirror patterns are considered. For one thing, the primary mirror is expected to construct with mosaic mirror with 24 trapezoidal (or petal) segments, for another thing, a monolithic mirror is also a candidate for its primary mirror. Both of them depend on active control technique to maintain the optical quality of the ring mirror. As a solar telescope, the working conditions of the CGST are quite different from those of the stellar telescopes. To avoid the image deterioration due to the mirror seeing and dome seeing, especially in the case of the concentration of flux in a solar telescope, large aperture solar projects prefer to adopt open telescopes and open domes. In this circumstance, higher wind loads act on the primary mirror directly, which will cause position errors and figure errors of the primary with matters worse than those of the current 10-meter stellar telescopes with dome protect. Therefore, it gives new challenges to the active control capability, telescope structure design, and wind shielding design. In this paper, the study progress of active control of CGST for its mosaic and monolithic mirror are presented, and the wind effects on such two primary mirrors are also investigated.

  11. The Solar System Ballet: A Kinesthetic Spatial Astronomy Activity

    Science.gov (United States)

    Heyer, Inge; Slater, T. F.; Slater, S. J.; Astronomy, Center; Education ResearchCAPER, Physics

    2011-05-01

    The Solar System Ballet was developed in order for students of all ages to learn about the planets, their motions, their distances, and their individual characteristics. To teach people about the structure of our Solar System can be revealing and rewarding, for students and teachers. Little ones (and some bigger ones, too) often cannot yet grasp theoretical and spatial ideas purely with their minds. Showing a video is better, but being able to learn with their bodies, essentially being what they learn about, will help them understand and remember difficult concepts much more easily. There are three segments to this activity, which can be done together or separately, depending on time limits and age of the students. Part one involves a short introductory discussion about what students know about the planets. Then students will act out the orbital motions of the planets (and also moons for the older ones) while holding a physical model. During the second phase we look at the structure of the Solar System as well as the relative distances of the planets from the Sun, first by sketching it on paper, then by recreating a scaled version in the class room. Again the students act out the parts of the Solar System bodies with their models. The third segment concentrates on recreating historical measurements of Earth-Moon-Sun system. The Solar System Ballet activity is suitable for grades K-12+ as well as general public informal learning activities.

  12. Predicting Solar Activity Using Machine-Learning Methods

    Science.gov (United States)

    Bobra, M.

    2017-12-01

    Of all the activity observed on the Sun, two of the most energetic events are flares and coronal mass ejections. However, we do not, as of yet, fully understand the physical mechanism that triggers solar eruptions. A machine-learning algorithm, which is favorable in cases where the amount of data is large, is one way to [1] empirically determine the signatures of this mechanism in solar image data and [2] use them to predict solar activity. In this talk, we discuss the application of various machine learning algorithms - specifically, a Support Vector Machine, a sparse linear regression (Lasso), and Convolutional Neural Network - to image data from the photosphere, chromosphere, transition region, and corona taken by instruments aboard the Solar Dynamics Observatory in order to predict solar activity on a variety of time scales. Such an approach may be useful since, at the present time, there are no physical models of flares available for real-time prediction. We discuss our results (Bobra and Couvidat, 2015; Bobra and Ilonidis, 2016; Jonas et al., 2017) as well as other attempts to predict flares using machine-learning (e.g. Ahmed et al., 2013; Nishizuka et al. 2017) and compare these results with the more traditional techniques used by the NOAA Space Weather Prediction Center (Crown, 2012). We also discuss some of the challenges in using machine-learning algorithms for space science applications.

  13. DASL-Data and Activities for Solar Learning

    Science.gov (United States)

    Jones, Harrison P.; Henney, Carl; Hill, Frank; Gearen, Michael; Pompca, Stephen; Stagg, Travis; Stefaniak, Linda; Walker, Connie

    2004-01-01

    DASL-Data and Activities for Solar Learning Data and Activities for Solar Learning (DASL) provides a classroom learning environment based on a twenty-five year record of solar magnetograms from the National Solar Observatory (NSO) at Kitt Peak, AZ. The data, together with image processing software for Macs or PCs, can be used to learn basic facts about the Sun and astronomy at the middle school level. At the high school level, students can study properties of the Sun's magnetic cycle with classroom exercises emphasizing data and error analysis and can participate in a new scientific study, Research in Active Solar Longitudes (RASL), in collaboration with classrooms throughout the country and scientists at NSO and NASA. We present a half-day course to train teachers in the scientific content of the project and its classroom use. We will provide a compact disc with the data and software and will demonstrate software installation and use, classroom exercises, and participation in RASL with computer projection.

  14. Rotation of the Earth, solar activity and cosmic ray intensity

    Energy Technology Data Exchange (ETDEWEB)

    Barlyaeva, T.; Bard, E. [Aix-Marseille Univ., CNRS, IRD, Aix-en-Provence (France). CEREGE, College de France; Abarca-del-Rio, R. [Universidad de Concepcion (UDEC) (Chile). Dept. de Geofisica (DGEO)

    2014-10-01

    We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

  15. Rotation of the Earth, solar activity and cosmic ray intensity

    International Nuclear Information System (INIS)

    Barlyaeva, T.; Bard, E.

    2014-01-01

    We analyse phase lags between the 11-year variations of three records: the semi-annual oscillation of the length of day (LOD), the solar activity (SA) and the cosmic ray intensity (CRI). The analysis was done for solar cycles 20-23. Observed relationships between LOD, CRI and SA are discussed separately for even and odd solar cycles. Phase lags were calculated using different methods (comparison of maximal points of cycles, maximal correlation coefficient, line of synchronization of cross-recurrence plots). We have found different phase lags between SA and CRI for even and odd solar cycles, confirming previous studies. The evolution of phase lags between SA and LOD as well as between CRI and LOD shows a positive trend with additional variations of phase lag values. For solar cycle 20, phase lags between SA and CRI, between SA and LOD, and between CRI and LOD were found to be negative. Overall, our study suggests that, if anything, the length of day could be influenced by solar irradiance rather than by cosmic rays.

  16. Solar activity effects in the ionospheric D region

    Directory of Open Access Journals (Sweden)

    A. D. Danilov

    1998-12-01

    Full Text Available Variations in the D-region electron concentration within the solar activity cycle are considered. It is demonstrated that conclusions of various authors, who have analyzed various sets of experimental data on [e], differ significantly. The most reliable seem to be the conclusions based on analysis of the [e] measurements carried out by the Faraday rotation method and on the theoretical concepts on the D-region photochemistry. Possible QBO effects in the relation of [e] to solar activity are considered and an assumption is made that such effects may be the reason for the aforementioned disagreement in conclusions on the [e] relation to solar indices.Key words. Atmospheric composition and structure · Ion chemistry of the atmosphere · Middle atmosphere

  17. A Kinetic Model to Explain the Maximum in alpha-Amylase Activity Measurements in the Presence of Small Carbohydrates

    NARCIS (Netherlands)

    Baks, T.; Janssen, A.E.M.; Boom, R.M.

    2006-01-01

    The effect of the presence of several small carbohydrates on the measurement of the -amylase activity was determined over a broad concentration range. At low carbohydrate concentrations, a distinct maximum in the -amylase activity versus concentration curves was observed in several cases. At higher

  18. Variations in Solar Parameters and Cosmic Rays with Solar Magnetic Polarity

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S. [Department of Earth Science Education, Chonnam National University, Gwangju, 61186 (Korea, Republic of); Yi, Y., E-mail: suyeonoh@jnu.ac.kr [Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon, 34134 (Korea, Republic of)

    2017-05-01

    The sunspot number varies with the 11-year Schwabe cycle, and the solar magnetic polarity reverses every 11 years approximately at the solar maximum. Because of polarity reversal, the difference between odd and even solar cycles is seen in solar activity. In this study, we create the mean solar cycle expressed by phase using the monthly sunspot number for all solar cycles 1–23. We also generate the mean solar cycle for sunspot area, solar radio flux, and cosmic ray flux within the allowance of observational range. The mean solar cycle has one large peak at solar maximum for odd solar cycles and two small peaks for most even solar cycles. The odd and even solar cycles have the statistical difference in value and shape at a confidence level of at least 98%. For solar cycles 19–23, the second peak in the even solar cycle is larger than the first peak. This result is consistent with the frequent solar events during the declining phase after the solar maximum. The difference between odd and even solar cycles can be explained by a combined model of polarity reversal and solar rotation. In the positive/negative polarity, the polar magnetic field introduces angular momentum in the same/opposite direction as/to the solar rotation. Thus the addition/subtraction of angular momentum can increase/decrease the motion of plasma to support the formation of sunspots. Since the polarity reverses at the solar maximum, the opposite phenomenon occurs in the declining phase.

  19. Latitude and Power Characteristics of Solar Activity at the End of the Maunder Minimum

    Science.gov (United States)

    Ivanov, V. G.; Miletsky, E. V.

    2017-12-01

    Two important sources of information about sunspots in the Maunder minimum are the Spörer catalog (Spörer, 1889) and observations of the Paris observatory (Ribes and Nesme-Ribes, 1993), which cover in total the last quarter of the 17th and the first two decades of the 18th century. These data, in particular, contain information about sunspot latitudes. As we showed in (Ivanov et al., 2011; Ivanov and Miletsky, 2016), dispersions of sunspot latitude distributions are tightly related to sunspot indices, and we can estimate the level of solar activity in the past using a method which is not based on direct calculation of sunspots and weakly affected by loss of observational data. The latitude distributions of sunspots in the time of transition from the Maunder minimum to the regular regime of solar activity proved to be wide enough. It gives evidences in favor of, first, not very low cycle no.-3 (1712-1723) with the Wolf number in maximum W = 100 ± 50, and, second, nonzero activity in the maximum of cycle no.-4 (1700-1711) W = 60 ± 45. Therefore, the latitude distributions in the end of the Maunder minimum are in better agreement with the traditional Wolf numbers and new revisited indices of activity SN and GN (Clette et al., 2014; Svalgaard and Schatten, 2016) than with the GSN (Hoyt and Schatten, 1998); the latter provide much lower level of activity in this epoch.

  20. Solar activity and its evolution across the corona: recent advances

    Directory of Open Access Journals (Sweden)

    Rodriguez Luciano

    2013-04-01

    Full Text Available Solar magnetism is responsible for the several active phenomena that occur in the solar atmosphere. The consequences of these phenomena on the solar-terrestrial environment and on Space Weather are nowadays clearly recognized, even if not yet fully understood. In order to shed light on the mechanisms that are at the basis of the Space Weather, it is necessary to investigate the sequence of phenomena starting in the solar atmosphere and developing across the outer layers of the Sun and along the path from the Sun to the Earth. This goal can be reached by a combined multi-disciplinary, multi-instrument, multi-wavelength study of these phenomena, starting with the very first manifestation of solar active region formation and evolution, followed by explosive phenomena (i.e., flares, erupting prominences, coronal mass ejections, and ending with the interaction of plasma magnetized clouds expelled from the Sun with the interplanetary magnetic field and medium. This wide field of research constitutes one of the main aims of COST Action ES0803: Developing Space Weather products and services in Europe. In particular, one of the tasks of this COST Action was to investigate the Progress in Scientific Understanding of Space Weather. In this paper we review the state of the art of our comprehension of some phenomena that, in the scenario outlined above, might have a role on Space Weather, focusing on the researches, thematic reviews, and main results obtained during the COST Action ES0803.

  1. A Solar Station for Education and Research on Solar Activity at a National University in Peru

    Science.gov (United States)

    Ishitsuka, J. K.

    2006-11-01

    pepe@geo.igp.gob.pe Beginning in 1937, the Carnegie Institution of Washington made active regional observations with a spectro-helioscope at the Huancayo Observatory. In 1957, during the celebration of the International Geophysical Year Mutsumi Ishitsuka arrived at the Geophysical Institute of Peru and restarted solar observations from the Huancayo Observatory. Almost 69 years have passed and many contributions for the geophysical and solar sciences have been made. Now the Instituto Geofisico del Peru (IGP), in cooperation with the Faculty of Sciences of the Universidad Nacional San Luis Gonzaga de Ica (UNICA), and with the support of the National Astronomical Observatory of Japan, are planning to construct a solar station refurbishing a coelostat that worked for many years at the Huancayo Observatory. A 15 cm refractor telescope is already installed at the university, for the observation of sunspots. A solar Flare Monitor Telescope (FMT) from Hida Observatory of Kyoto University could be sent to Peru and installed at the solar station at UNICA. As the refurbished coelostat, FMT will become a good tool to improve education and research in sciences.

  2. Quasi-biennial modulation of solar neutrino flux: connections with solar activity

    Science.gov (United States)

    Vecchio, A.; Laurenza, M.; D'alessi, L.; Carbone, V.; Storini, M.

    2011-12-01

    A quasi-biennial periodicity has been recently found (Vecchio et al., 2010) in the solar neutrino flux, as detected at the Homestake experiment, as well as in the flux of solar energetic protons, by means of the Empirical Modes Decomposition technique. Moreover, both fluxes have been found to be significantly correlated at the quasi-biennial timescale, thus supporting the hypothesis of a connection between solar neutrinos and solar activity. The origin of this connection is investigated, by modeling how the standard Mikheyev-Smirnov-Wolfenstein (MSW) effect (the process for which the well-known neutrino flavor oscillations are modified in passing through the material) could be influenced by matter fluctuations. As proposed by Burgess et al., 2004, by introducing a background magnetic field in the helioseismic model, density fluctuations can be excited in the radiative zone by the resonance between helioseismic g-modes and Alfvén waves. In particular, with reasonable values of the background magnetic field (10-100 kG), the distance between resonant layers could be of the same order of neutrino oscillation length. We study the effect over this distance of a background magnetic field which is variable with a ~2 yr period, in agreement with typical variations of solar activity. Our findings suggest that the quasi-biennial modulation of the neutrino flux is theoretically possible as a consequence of the magnetic field variations in the solar interior. A. Vecchio, M. Laurenza, V. Carbone, M. Storini, The Astrophysical Journal Letters, 709, L1-L5 (2010). C. Burgess, N. S. Dzhalilov, T. I. Rashba, V., B.Semikoz, J. W. F. Valle, Mon. Not. R. Astron. Soc., 348, 609-624 (2004).

  3. Development of an active solar crop dryer: design analysis and ...

    African Journals Online (AJOL)

    The design analysis and performance evaluation of an active solar crop dryer was undertaken by drying marched cassava. The drying rate, system drying, collector and pick-up efficiencies were 1.6kg/day (14%/day), 9%, 46% and 29% respectively. Comparatively, the drying rate for sun drying was 0.9kg/day. The collector ...

  4. Physics of the Solar Active Regions from Radio Observations

    Science.gov (United States)

    Gelfreikh, G. B.

    1999-12-01

    Localized increase of the magnetic field observed by routine methods on the photosphere result in the growth of a number of active processes in the solar atmosphere and the heliosphere. These localized regions of increased magnetic field are called active regions (AR). The main processes of transfer, accumulation and release of energy in an AR is, however, out of scope of photospheric observations being essentially a 3D-process and happening either under photosphere or up in the corona. So, to investigate these plasma structures and processes we are bound to use either extrapolation of optical observational methods or observations in EUV, X-rays and radio. In this review, we stress and illustrate the input to the problem gained from radio astronomical methods and discuss possible future development of their applicatications. Historically speaking each new step in developing radio technique of observations resulted in detecting some new physics of ARs. The most significant progress in the last few years in radio diagnostics of the plasma structures of magnetospheres of the solar ARs is connected with the developing of the 2D full disk analysis on regular basis made at Nobeyama and detailed multichannel spectral-polarization (but one-dimensional and one per day) solar observations at the RATAN-600. In this report the bulk of attention is paid to the new approach to the study of solar activity gained with the Nobeyama radioheliograph and analyzing the ways for future progress. The most important new features of the multicomponent radio sources of the ARs studied using Nobeyama radioheliograph are as follow: 1. The analysis of magnetic field structures in solar corona above sunspot with 2000 G. Their temporal evolution and fluctuations with the periods around 3 and 5 minutes, due to MHD-waves in sunspot magnetic tubes and surrounding plasma. These investigations are certainly based on an analysis of thermal cyclotron emission of lower corona and CCTR above sunspot

  5. Computational analysis of the maximum power point for GaAs sub-cells in InGaP/GaAs/Ge triple-junction space solar cells

    International Nuclear Information System (INIS)

    Cappelletti, M A; Cédola, A P; Peltzer y Blancá, E L

    2014-01-01

    The radiation resistance in InGaP/GaAs/Ge triple-junction solar cells is limited by that of the middle GaAs sub-cell. In this work, the electrical performance degradation of different GaAs sub-cells under 1 MeV electron irradiation at fluences below 4 × 10 15 cm −2 has been analyzed by means of a computer simulation. The numerical simulations have been carried out using the one-dimensional device modeling program PC1D. The effects of the base and emitter carrier concentrations of the p- and n-type GaAs structures on the maximum power point have been researched using a radiative recombination lifetime, a damage constant for the minority carrier lifetime and carrier removal rate models. An analytical model has been proposed, which is useful to either determine the maximum exposure time or select the appropriate device in order to ensure that the electrical parameters of different GaAs sub-cells will have a satisfactory response to radiation since they will be kept above 80% with respect to the non-irradiated values. (paper)

  6. Cosmic Ray Daily Variation And SOLAR Activity On Anomalous Days

    International Nuclear Information System (INIS)

    Mishra, Rajesh Kumar; Mishra, Rekha Agarwal

    2008-01-01

    A study is carried out on the long-term changes in the diurnal anisotropy of cosmic rays using the ground based Deep River neutron monitor data during significantly low amplitude anisotropic wave train events in cosmic ray intensity for the period 1981-94. It has been observed that the phase of the diurnal anisotropy for majority of the low amplitude anisotropic wave train events significantly shifts towards earlier hours as compared to the co-rotational direction. The long-term behaviour of the amplitude of the diurnal anisotropy can be explained in terms of the occurrence of low amplitude anisotropic wave train events. The occurrence of these events is dominant during solar activity minimum years. The amplitude of the diurnal anisotropy is well correlated with the solar cycle but the direction of the anisotropy is not correlated with the solar cycle and shows a systematic shift to earlier hours. (authors)

  7. DATA ASSIMILATION APPROACH FOR FORECAST OF SOLAR ACTIVITY CYCLES

    Energy Technology Data Exchange (ETDEWEB)

    Kitiashvili, Irina N., E-mail: irina.n.kitiashvili@nasa.gov [NASA Ames Research Center, Moffett Field, Mountain View, CA 94035 (United States)

    2016-11-01

    Numerous attempts to predict future solar cycles are mostly based on empirical relations derived from observations of previous cycles, and they yield a wide range of predicted strengths and durations of the cycles. Results obtained with current dynamo models also deviate strongly from each other, thus raising questions about criteria to quantify the reliability of such predictions. The primary difficulties in modeling future solar activity are shortcomings of both the dynamo models and observations that do not allow us to determine the current and past states of the global solar magnetic structure and its dynamics. Data assimilation is a relatively new approach to develop physics-based predictions and estimate their uncertainties in situations where the physical properties of a system are not well-known. This paper presents an application of the ensemble Kalman filter method for modeling and prediction of solar cycles through use of a low-order nonlinear dynamo model that includes the essential physics and can describe general properties of the sunspot cycles. Despite the simplicity of this model, the data assimilation approach provides reasonable estimates for the strengths of future solar cycles. In particular, the prediction of Cycle 24 calculated and published in 2008 is so far holding up quite well. In this paper, I will present my first attempt to predict Cycle 25 using the data assimilation approach, and discuss the uncertainties of that prediction.

  8. Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

    Science.gov (United States)

    Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

    2018-03-01

    In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

  9. Periodic and quiescent solar activity effects in the low ionosphere, using SAVNET data

    Science.gov (United States)

    Bertoni, F. C. P.; Raulin, J.-P.; Gavilan, H. R.; Kaufmann, P.; Raymundo, T. E.

    2010-10-01

    Important results have been acquired using the measurements of VLF amplitude and phase signals from the South America VLF Network (SAVNET) stations. This network is an international project coordinated by CRAAM, Brazil in cooperation with Peru and Argentina. It started operating in April 2006, and now counts on eight stations (Atibaia, Palmas, Santa Maria and Estaça~o Antártica Comandante Ferraz in Brazil; Piura, Punta-Lobos and Ica, in Peru; CASLEO, in Argentina). Researches, through the last decades, have demonstrated the versatility of the VLF technique for many scientific and technological purposes. In this work, we summarize some recent results using SAVNET data base. We have obtained daily maximum diurnal amplitude time series that exhibited behavior patterns in different time scales: 1) 1ong term variations indicating the solar activity level control of the low ionosphere; 2) characteristic periods of alternated slow and fast variations, the former being related to solar illumination conditions, and the latter that have been associated with the winter anomaly at high latitudes; 3) 27-days period related to the solar rotation and consequently associated to the solar Lyman-α radiation flux variations, reinforcing earlier theories about the importance of this spectral line for the D-region formation. Finally, we conclude presenting preliminary results of simulation using LWPC, which showed very good agreement at times of observed modal amplitude minima for a given VLF propagation path.

  10. Solar optics-based active panel for solar energy storage and disinfection of greywater.

    Science.gov (United States)

    Lee, W; Song, J; Son, J H; Gutierrez, M P; Kang, T; Kim, D; Lee, L P

    2016-09-01

    Smart city and innovative building strategies are becoming increasingly more necessary because advancing a sustainable building system is regarded as a promising solution to overcome the depleting water and energy. However, current sustainable building systems mainly focus on energy saving and miss a holistic integration of water regeneration and energy generation. Here, we present a theoretical study of a solar optics-based active panel (SOAP) that enables both solar energy storage and photothermal disinfection of greywater simultaneously. Solar collector efficiency of energy storage and disinfection rate of greywater have been investigated. Due to the light focusing by microlens, the solar collector efficiency is enhanced from 25% to 65%, compared to that without the microlens. The simulation of greywater sterilization shows that 100% disinfection can be accomplished by our SOAP for different types of bacteria including Escherichia coli . Numerical simulation reveals that our SOAP as a lab-on-a-wall system can resolve the water and energy problem in future sustainable building systems.

  11. Online educative activities for solar ultraviolet radiation based on measurements of cloud amount and solar exposures.

    Science.gov (United States)

    Parisi, A V; Downs, N; Turner, J; Amar, A

    2016-09-01

    A set of online activities for children and the community that are based on an integrated real-time solar UV and cloud measurement system are described. These activities use the functionality of the internet to provide an educative tool for school children and the public on the influence of cloud and the angle of the sun above the horizon on the global erythemal UV or sunburning UV, the diffuse erythemal UV, the global UVA (320-400nm) and the vitamin D effective UV. Additionally, the units of UV exposure and UV irradiance are investigated, along with the meaning and calculation of the UV index (UVI). This research will help ensure that children and the general public are better informed about sun safety by improving their personal understanding of the daily and the atmospheric factors that influence solar UV radiation and the solar UV exposures of the various wavebands in the natural environment. The activities may correct common misconceptions of children and the public about UV irradiances and exposure, utilising the widespread reach of the internet to increase the public's awareness of the factors influencing UV irradiances and exposures in order to provide clear information for minimizing UV exposure, while maintaining healthy, outdoor lifestyles. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Ionospheric Peak Electron Density and Performance Evaluation of IRI-CCIR Near Magnetic Equator in Africa During Two Extreme Solar Activities

    Science.gov (United States)

    Adebesin, B. O.; Rabiu, A. B.; Obrou, O. K.; Adeniyi, J. O.

    2018-03-01

    The F2 layer peak electron density (NmF2) was investigated over Korhogo (Geomagnetic: 1.26°S, 67.38°E), a station near the magnetic equator in the African sector. Data for 1996 and 2000 were, respectively, categorized into low solar quiet and disturbed and high solar quiet and disturbed. NmF2 prenoon peak was higher than the postnoon peak during high solar activity irrespective of magnetic activity condition, while the postnoon peak was higher for low solar activity. Higher NmF2 peak amplitude characterizes disturbed magnetic activity than quiet magnetic condition for any solar activity. The maximum peaks appeared in equinox. June solstice noontime bite out lagged other seasons by 1-2 h. For any condition of solar and magnetic activities, the daytime NmF2 percentage variability (%VR) measured by the relative standard deviation maximizes/minimizes in June solstice/equinox. Daytime variability increases with increasing magnetic activity. The highest peak in the morning time NmF2 variability occurs in equinox, while the highest evening/nighttime variability appeared in June solstice for all solar/magnetic conditions. The nighttime annual variability amplitude is higher during disturbed than quiet condition regardless of solar activity period. At daytime, variability is similar for all conditions of solar activities. NmF2 at Korhogo is well represented on the International Reference Ionosphere-International Radio Consultative Committee (IRI-CCIR) option. The model/observation relationship performed best between local midnight and postmidnight period (00-08 LT). The noontime trough characteristics is not prominent in the IRI pattern during high solar activity but evident during low solar conditions when compared with Korhogo observations. The Nash-Sutcliffe coefficients revealed better model performance during disturbed activities.

  13. Solar activity influence on air temperature regimes in caves

    Science.gov (United States)

    Stoeva, Penka; Mikhalev, Alexander; Stoev, Alexey

    Cave atmospheres are generally included in the processes that happen in the external atmosphere as circulation of the cave air is connected with the most general circulation of the air in the earth’s atmosphere. Such isolated volumes as the air of caves are also influenced by the variations of solar activity. We discuss cave air temperature response to climate and solar and geomagnetic activity for four show caves in Bulgaria studied for a period of 46 years (1968 - 2013). Everyday noon measurements in Ledenika, Saeva dupka, Snezhanka and Uhlovitsa cave have been used. Temperatures of the air in the zone of constant temperatures (ZCT) are compared with surface temperatures recorded at meteorological stations situated near about the caves - in the towns of Vratsa, Lovech, Peshtera and Smolyan, respectively. For comparison, The Hansen cave, Middle cave and Timpanogos cave from the Timpanogos Cave National Monument, Utah, USA situated nearly at the same latitude have also been examined. Our study shows that the correlation between cave air temperature time series and sunspot number is better than that between the cave air temperature and Apmax indices; that t°ZCT is rather connected with the first peak in geomagnetic activity, which is associated with transient solar activity (CMEs) than with the second one, which is higher and connected with the recurrent high speed streams from coronal holes. Air temperatures of all examined show caves, except the Ledenika cave, which is ice cave show decreasing trends. On the contrary, measurements at the meteorological stations show increasing trends in the surface air temperatures. The trend is decreasing for the Timpanogos cave system, USA. The conclusion is that surface temperature trends depend on the climatic zone, in which the cave is situated, and there is no apparent relation between temperatures inside and outside the caves. We consider possible mechanism of solar cosmic rays influence on the air temperatures in caves

  14. Prediction of solar activity from solar background magnetic field variations in cycles 21-23

    International Nuclear Information System (INIS)

    Shepherd, Simon J.; Zharkov, Sergei I.; Zharkova, Valentina V.

    2014-01-01

    A comprehensive spectral analysis of both the solar background magnetic field (SBMF) in cycles 21-23 and the sunspot magnetic field in cycle 23 reported in our recent paper showed the presence of two principal components (PCs) of SBMF having opposite polarity, e.g., originating in the northern and southern hemispheres, respectively. Over a duration of one solar cycle, both waves are found to travel with an increasing phase shift toward the northern hemisphere in odd cycles 21 and 23 and to the southern hemisphere in even cycle 22. These waves were linked to solar dynamo waves assumed to form in different layers of the solar interior. In this paper, for the first time, the PCs of SBMF in cycles 21-23 are analyzed with the symbolic regression technique using Hamiltonian principles, allowing us to uncover the underlying mathematical laws governing these complex waves in the SBMF presented by PCs and to extrapolate these PCs to cycles 24-26. The PCs predicted for cycle 24 very closely fit (with an accuracy better than 98%) the PCs derived from the SBMF observations in this cycle. This approach also predicts a strong reduction of the SBMF in cycles 25 and 26 and, thus, a reduction of the resulting solar activity. This decrease is accompanied by an increasing phase shift between the two predicted PCs (magnetic waves) in cycle 25 leading to their full separation into the opposite hemispheres in cycle 26. The variations of the modulus summary of the two PCs in SBMF reveals a remarkable resemblance to the average number of sunspots in cycles 21-24 and to predictions of reduced sunspot numbers compared to cycle 24: 80% in cycle 25 and 40% in cycle 26.

  15. Proton Flares in Solar Activity Complexes: Possible Origins and Consequences

    Science.gov (United States)

    Isaeva, E. S.; Tomozov, V. M.; Yazev, S. A.

    2018-03-01

    Solar flares observed during the 24th solar-activity cycle and accompanied by fluxes of particles detected at the Earth's orbit with intensities exceeding 10 particles cm-2 s-1 and energies of more than 10 MeV per particle mainly occurred in activity complexes (82% of cases), with 80% of these occurring no more than 20 heliographic degrees from the nearest coronal holes. The correlation between the X-ray classes of flares and the proton fluxes detected at the Earth's orbit is weak. The work presented here supports the hypothesis that the leakage of particles into the heliosphere is due to the existence of long-lived magnetic channels, which facilitate the transport of flare-accelerated particles into the boundary regions of open magnetic structures of coronal holes. The possible contribution of exchange reconnection in the formation of such channels and the role of exchange reconnection in the generation of flares are discussed.

  16. Análise de repetibilidade de caracteres forrageiros de genótipos de Panicum maximum, avaliados com e sem restrição solar Repeatability analysis of forage traits of Panicum maximum genotypes evaluated under natural and attenuated solar radiation

    Directory of Open Access Journals (Sweden)

    Alberto Cargnelutti Filho

    2004-06-01

    Full Text Available O objetivo do trabalho foi determinar o número de medições necessárias à predição do desempenho de cinco genótipos de Panicum maximum Jacq. Os genótipos (Gatton, Vencedor, Mombaça, Tanzânia e Tobiatã foram avaliados sob os sistemas de cultivo com e sem restrição solar, na Fundação Estadual de Pesquisa Agropecuária, situada em Tupanciretã - Rio Grande do Sul. No sistema de cultivo com restrição solar, os genótipos foram avaliados sob um bosque de eucalipto. Em cada uma das oito medições (cortes, foram avaliadas a matéria seca total, matéria seca de folhas, matéria seca de colmo, matéria seca folha + colmo, altura de planta e relação matéria seca folha/colmo. As estimativas dos coeficientes de repetibilidade foram obtidas por três métodos - análise da variância, componentes principais e análise estrutural. Concluiu-se que os oito cortes possibilitaram selecionar genótipos superiores em relação a todas as características, com 80% de exatidão no prognóstico de seu valor real.The objective of this study was to determine how many evaluations were necessary to predict the performance of Panicum maximum Jacq. genotypes. The genotypes Gatton, Vencedor, Mombaça, Tanzânia, and Tobiatã were evaluated under natural and attenuated solar radiation at the Fundação Estadual de Pesquisa Agropecuária, Tupanciretã, RS. Attenuated solar radiation was obtained when plants were grown in Eucalyptus woods. Genotypes in both crop systems were evaluated eight times. Total dry matter production, leaf, stem, and leaf plus stem dry matter, plant height and index of leaf and stem dry matter were recorded each evaluation time. Repeatability estimations were obtained through variance, structural, and principal component analysis. In conclusion, eight evaluations permit to select superior Panicum maximum genotypes, considering all characteristics, with 80% accuracy of the real value.

  17. Solar activity impact on the Earth’s upper atmosphere

    Czech Academy of Sciences Publication Activity Database

    Kutiev, I.; Tsagouri, I.; Perrone, L.; Pancheva, D.; Mukhtarov, P.; Mikhailov, A.; Laštovička, Jan; Jakowski, N.; Burešová, Dalia; Blanch, E.; Andonov, B.; Altadill, D.; Magdaleno, S.; Parisi, M.; Torta, J. M.

    2013-01-01

    Roč. 3, February (2013), A06/1-A06/21 ISSN 2115-7251 Grant - others:COST(XE) ES0803 Institutional support: RVO:68378289 Keywords : ionosphere * solar activity * storm * total electron content * data analysis Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.519, year: 2013 http://www.swsc-journal.org/index.php?option=com_article&access=doi&doi=10.1051/swsc/2013028&Itemid=129

  18. Solar activity: nowcasting and forecasting at the SIDC

    Directory of Open Access Journals (Sweden)

    D. Berghmans

    2005-11-01

    Full Text Available The Solar Influences Data analysis Center (SIDC is the World Data Center for the production and the distribution of the International Sunspot Index, coordinating a network of about 80 stations worldwide. From this core activity, the SIDC has grown in recent years to a European center for nowcasting and forecasting of solar activity on all timescales. This paper reviews the services (data, forecasts, alerts, software that the SIDC currently offers to the scientific community. The SIDC operates instruments both on the ground and in space. The USET telescope in Brussels produces daily white light and Hα images. Several members of the SIDC are co-investigators of the EIT instrument onboard SOHO and are involved in the development of the next generation of Europe's solar weather monitoring capabilities. While the SIDC is staffed only during day-time (7 days/week, the monitoring service is a 24 h activity thanks to the implementation of autonomous software for data handling and analysis and the sending of automated alerts. We will give an overview of recently developed techniques for visualization and automated analysis of solar images and detection of events significant for space weather (e.g. CMEs or EIT waves. As part of the involvement of the SIDC in the ESA Pilot Project for Space Weather Applications we have developed services dedicated to the users of the Global Positioning System (GPS. As a Regional Warning Center (RWC of the International Space Environment Service (ISES, the SIDC produces daily forecasts of flaring probability, geomagnetic activity and 10.7 cm radio flux. The accuracy of these forecasts will be investigated through an in-depth quality analysis.

  19. A Simple Technique for Sustaining Solar Energy Production in Active Convective Coastal Regions

    Directory of Open Access Journals (Sweden)

    Moses E. Emetere

    2016-01-01

    Full Text Available The climatic factors in the coastal areas are cogent in planning a stable and functional solar farm. 3D simulations relating the surface temperature, sunshine hour, and solar irradiance were adopted to see the effect of minute changes of other meteorological parameters on solar irradiance. This enabled the day-to-day solar radiation monitoring with the primary objective to examine the best technique for maximum power generation via solar option in coastal locations. The month of January had the highest turbulent features, showing the influence of weather and the poorest solar radiance due to low sunshine hour. Twenty-year weather parameters in the research area were simulated to express the systematic influence of weather of PV performance. A theoretical solar farm was illustrated to generate stable power supply with emphasis on the longevity of the PV module proposed by introducing an electronic concentrator pillar (CP. The pictorial and operational model of the solar farm was adequately explained.

  20. Fe/O ratio behavior as an indicator of solar plasma state at different solar activity manifestations and in periods of their absence

    Science.gov (United States)

    Minasyants, Gennady; Minasyants, Tamara; Tomozov, Vladimir

    2018-03-01

    We report the results of the investigation into plasma physical characteristics at various solar activity manifestations and in periods of their absence. These results have been obtained from quantitative estimates of the relative abundance of Fe/O ions in different energy ranges. Maximum values of the Fe/O ratio is shown to correspond to particle fluxes from impulsive flares for ions with energies decreases smoothly with ion energy and is noticeably inferior to values of fluxes in impulsive events. We have established that the properties of flares of solar cosmic rays indicate their belonging to a separate subclass in the total population of gradual events. Relying on variations in the abundance of Fe/O ions, we propose an explanation of the solar plasma behavior during the development of flares of both classes. Magnetic clouds (a separate type of coronal mass ejections (CME)), which have regions of turbulent compression and are sources of strong geomagnetic storms, exhibit a relative composition of Fe ions comparable to the abundance of Fe in ion fluxes from gradual flares. We have found out that the Fe/O value can be used to detect penetration of energetic flare plasma into the CME body at the initial phase of their joint development and to estimate its relative contribution. During solar minimum with the complete absence of sunspots, the Fe/O ratio during periods of "quiet" solar wind show absolutely low values of Fe/O=0.004-0.010 in the energy range from 2-5 to 30 MeV/n. This is associated with the manifestation of the cosmic ray anomalous component, which causes an increase in the intensity of ion fluxes with a high first ionization potential, including oxygen (O), and elements with a low first ionization potential (Fe) demonstrate the weakening of the fluxes. As for particles with higher energies (Ek>30 MeV/n), the Fe/O increase is due to the decisive influence of galactic cosmic rays on the composition of impurity elements in the solar wind under solar

  1. Imaging VLBI polarimetry data from Active Galactic Nuclei using the Maximum Entropy Method

    Directory of Open Access Journals (Sweden)

    Coughlan Colm P.

    2013-12-01

    Full Text Available Mapping the relativistic jets emanating from AGN requires the use of a deconvolution algorithm to account for the effects of missing baseline spacings. The CLEAN algorithm is the most commonly used algorithm in VLBI imaging today and is suitable for imaging polarisation data. The Maximum Entropy Method (MEM is presented as an alternative with some advantages over the CLEAN algorithm, including better spatial resolution and a more rigorous and unbiased approach to deconvolution. We have developed a MEM code suitable for deconvolving VLBI polarisation data. Monte Carlo simulations investigating the performance of CLEAN and the MEM code on a variety of source types are being carried out. Real polarisation (VLBA data taken at multiple wavelengths have also been deconvolved using MEM, and several of the resulting polarisation and Faraday rotation maps are presented and discussed.

  2. A comparison of photospheric electric current and ultraviolet and X-ray emission in a solar active region

    Science.gov (United States)

    Haisch, B. M.; Bruner, M. E.; Hagyard, M. J.; Bonnet, R. M.

    1986-01-01

    This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft X-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region.

  3. Comparison of photospheric electric current and ultraviolet and x-ray emission in a solar active region

    International Nuclear Information System (INIS)

    Haisch, B.M.; Bruner, M.E.; Hagyard, M.J.; Bonnet, R.M.; NASA, Marshall Space Flight Center, Huntsville, AL; ESA, Paris, France)

    1986-01-01

    This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft x-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region. 29 references

  4. The solar activity cycle physical causes and consequences

    CERN Document Server

    Hudson, Hugh; Petrovay, Kristóf; Steiger, Rudolf

    2015-01-01

    A collection of papers edited by four experts in the field, this book sets out to describe the way solar activity is manifested in observations of the solar interior, the photosphere, the chromosphere, the corona and the heliosphere. The 11-year solar activity cycle, more generally known as the sunspot cycle, is a fundamental property of the Sun.  This phenomenon is the generation and evolution of magnetic fields in the Sun’s convection zone, the photosphere.  It is only by the careful enumeration and description of the phenomena and their variations that one can clarify their interdependences.   The sunspot cycle has been tracked back about four centuries, and it has been recognized that to make this data set a really useful tool in understanding how the activity cycle works and how it can be predicted, a very careful and detailed effort is needed to generate sunspot numbers.  This book deals with this topic, together with several others that present related phenomena that all indicate the physical pr...

  5. A study of the asymmetrical distribution of solar activity features on solar and plasma parameters (1967-2016)

    Science.gov (United States)

    El-Borie, M. A.; El-Taher, A. M.; Aly, N. E.; Bishara, A. A.

    2018-04-01

    The impact of asymmetrical distribution of hemispheric sunspot areas (SSAs) on the interplanetary magnetic field, plasma, and solar parameters from 1967 to 2016 has been studied. The N-S asymmetry of solar-plasma activities based on SSAs has a northern dominance during solar cycles 20 and 24. However, it has a tendency to shift to the southern hemisphere in cycles 21, 22, and 23. The solar cycle 23 showed that the sorted southern SSAs days predominated over the northern days by ˜17%. Through the solar cycles 21-24, the SSAs of the southern hemisphere were more active. In contrast, the northern SSAs predominate over the southern one by 9% throughout solar cycle 20. On the other hand, the average differences of field magnitude for the sorted northern and southern groups during solar cycles 20-24 are statistically insignificant. Clearly, twenty years showed that the solar plasma ion density from the sorted northern group was denser than that of southern group and a highest northern dominant peak occurred in 1971. In contrast, seventeen out of fifty years showed the reverse. In addition, there are fifteen clear asymmetries of solar wind speed (SWS), with SWS (N) > SWS (S), and during the years 1972, 2002, and 2008, the SWS from the sorted northern group was faster than that of southern activity group by 6.16 ± 0.65 km/s, 5.70 ± 0.86 km/s, and 5.76 ± 1.35 km/s, respectively. For the solar cycles 20-24, the grand-averages of P from the sorted solar northern and southern have nearly the same parameter values. The solar plasma was hotter for the sorted northern activity group than the southern ones for 17 years out of 50. Most significant northern prevalent asymmetries were found in 1972 (5.76 ± 0.66 × 103 K) and 1996 (4.7 ± 0.8 × 103 K), while two significant equivalent dominant southern asymmetries (˜3.8 ± 0.3 × 103 K) occurred in 1978 and 1993. The grand averages of sunspot numbers have symmetric activity for the two sorted northern and southern hemispheres

  6. Comparison of theoretically predicted and observed Solar Maximum Mission X-ray spectra for the 1980 April 13 and May 9 flares

    International Nuclear Information System (INIS)

    Smith, D.F.; Orwig, L.E.

    1982-01-01

    A method for predicting the hard X-ray spectrum in the 10--100 keV range for compact flares during their initial rise is developed on the basis of a thermal model. Observations of the flares of 1980 April 13, 4:05 U.T., and 1980 May 9, 7:12 U.T. are given and their combined spectra from the Hard X-ray Burst Spectrometer and Hard X-ray Imaging Spectrometer on the Solar Maximum Mission are deduced. Constraints on the cross sectional area of the supposed emitting arch are obtained from data from the Hard X-ray Imaging Spectrometer. A power-law spectrum is predicted for the rise of the flare of April 13 for initial arch densities less than 10 10 cm -3 and also for the flare of May 9 for initial arch densities less than 5.4 x 10 10 cm -3 . In both cases power-law spectra are observed. Limitations and implications of these results are discussed

  7. On the possible relations between solar activities and global seismicity in the solar cycle 20 to 23

    Energy Technology Data Exchange (ETDEWEB)

    Herdiwijaya, Dhani, E-mail: dhani@as.itb.ac.id [Astronomy Research Division and Bosscha Observatory, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10, Bandung, Indonesia 40132 (Indonesia); Arif, Johan [Geology Research Division, Faculty of Earth Sciences and Technology, Bandung Institute of Technology, Ganesha 10, Bandung, Indonesia 40132 (Indonesia); Nurzaman, Muhamad Zamzam; Astuti, Isna Kusuma Dewi [Astronomy Study Program, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10, Bandung, Indonesia 40132 (Indonesia)

    2015-09-30

    Solar activities consist of high energetic particle streams, electromagnetic radiation, magnetic and orbital gravitational forces. The well-know solar activity main indicator is the existence of sunspot which has mean variation in 11 years, named by solar cycle, allow for the above fluctuations. Solar activities are also related to the space weather affecting all planetary atmospheric variability, moreover to the Earth’s climate variability. Large extreme space and geophysical events (high magnitude earthquakes, explosive volcanic eruptions, magnetic storms, etc.) are hazards for humankind, infrastructure, economies, technology and the activities of civilization. With a growing world population, and with modern reliance on delicate technological systems, human society is becoming increasingly vulnerable to natural hazardous events. The big question arises to the relation between solar forcing energy to the Earth’s global seismic activities. Estimates are needed for the long term occurrence-rate probabilities of these extreme natural hazardous events. We studied connectivity from yearly seismic activities that refer to and sunspot number within the solar cycle 20 to 23 of year 1960 to 2013 (53 years). We found clear evidences that in general high magnitude earthquake events and their depth were related to the low solar activity.

  8. On the possible relations between solar activities and global seismicity in the solar cycle 20 to 23

    Science.gov (United States)

    Herdiwijaya, Dhani; Arif, Johan; Nurzaman, Muhamad Zamzam; Astuti, Isna Kusuma Dewi

    2015-09-01

    Solar activities consist of high energetic particle streams, electromagnetic radiation, magnetic and orbital gravitational forces. The well-know solar activity main indicator is the existence of sunspot which has mean variation in 11 years, named by solar cycle, allow for the above fluctuations. Solar activities are also related to the space weather affecting all planetary atmospheric variability, moreover to the Earth's climate variability. Large extreme space and geophysical events (high magnitude earthquakes, explosive volcanic eruptions, magnetic storms, etc.) are hazards for humankind, infrastructure, economies, technology and the activities of civilization. With a growing world population, and with modern reliance on delicate technological systems, human society is becoming increasingly vulnerable to natural hazardous events. The big question arises to the relation between solar forcing energy to the Earth's global seismic activities. Estimates are needed for the long term occurrence-rate probabilities of these extreme natural hazardous events. We studied connectivity from yearly seismic activities that refer to and sunspot number within the solar cycle 20 to 23 of year 1960 to 2013 (53 years). We found clear evidences that in general high magnitude earthquake events and their depth were related to the low solar activity.

  9. Spectral Analysis of Geomagnetic Activity Indices and Solar Wind Parameters

    Directory of Open Access Journals (Sweden)

    Jung-Hee Kim

    2014-06-01

    Full Text Available Solar variability is widely known to affect the interplanetary space and in turn the Earth’s electromagnetical environment on the basis of common periodicities in the solar and geomagnetic activity indices. The goal of this study is twofold. Firstly, we attempt to associate modes by comparing a temporal behavior of the power of geomagnetic activity parameters since it is barely sufficient searching for common peaks with a similar periodicity in order to causally correlate geomagnetic activity parameters. As a result of the wavelet transform analysis we are able to obtain information on the temporal behavior of the power in the velocity of the solar wind, the number density of protons in the solar wind, the AE index, the Dst index, the interplanetary magnetic field, B and its three components of the GSM coordinate system, BX, BY, BZ. Secondly, we also attempt to search for any signatures of influence on the space environment near the Earth by inner planets orbiting around the Sun. Our main findings are as follows: (1 Parameters we have investigated show periodicities of ~ 27 days, ~ 13.5 days, ~ 9 days. (2 The peaks in the power spectrum of BZ appear to be split due to an unknown agent. (3 For some modes powers are not present all the time and intervals showing high powers do not always coincide. (4 Noticeable peaks do not emerge at those frequencies corresponding to the synodic and/or sidereal periods of Mercury and Venus, which leads us to conclude that the Earth’s space environment is not subject to the shadow of the inner planets as suggested earlier.

  10. Solar Energy Educational Material, Activities and Science Projects

    Science.gov (United States)

    dropdown arrow Site Map A-Z Index Menu Synopsis Solar Energy Educational Materials Solar with glasses " ;The sun has produced energy for billions of years. Solar energy is the solar radiation that reaches the earth. Solar energy can be converted directly or indirectly into other forms of energy, such as

  11. Periodic Variation of the North-South Asymmetry of Solar Activity ...

    Indian Academy of Sciences (India)

    Abstract. We report here a study of various solar activity phenomena occurring in both north and south hemispheres of the Sun during solar cycles 8-23. In the study we have used sunspot data for the period 1832—. 1976, flare index data for the period 1936-1993, Hα flare data 1993-1998 and solar active prominences data ...

  12. Magnetic nanoparticle imaging by random and maximum length sequences of inhomogeneous activation fields.

    Science.gov (United States)

    Baumgarten, Daniel; Eichardt, Roland; Crevecoeur, Guillaume; Supriyanto, Eko; Haueisen, Jens

    2013-01-01

    Biomedical applications of magnetic nanoparticles require a precise knowledge of their biodistribution. From multi-channel magnetorelaxometry measurements, this distribution can be determined by means of inverse methods. It was recently shown that the combination of sequential inhomogeneous excitation fields in these measurements is favorable regarding the reconstruction accuracy when compared to homogeneous activation . In this paper, approaches for the determination of activation sequences for these measurements are investigated. Therefor, consecutive activation of single coils, random activation patterns and families of m-sequences are examined in computer simulations involving a sample measurement setup and compared with respect to the relative condition number of the system matrix. We obtain that the values of this condition number decrease with larger number of measurement samples for all approaches. Random sequences and m-sequences reveal similar results with a significant reduction of the required number of samples. We conclude that the application of pseudo-random sequences for sequential activation in the magnetorelaxometry imaging of magnetic nanoparticles considerably reduces the number of required sequences while preserving the relevant measurement information.

  13. Multi-wavelength Observations of Solar Active Region NOAA 7154

    Science.gov (United States)

    Bruner, M. E.; Nitta, N. V.; Frank. Z. A.; Dame, L.; Suematsu, Y.

    2000-01-01

    We report on observations of a solar active region in May 1992 by the Solar Plasma Diagnostic Experiment (SPDE) in coordination with the Yohkoh satellite (producing soft X-ray images) and ground-based observatories (producing photospheric magnetograms and various filtergrams including those at the CN 3883 A line). The main focus is a study of the physical conditions of hot (T is approximately greater than 3 MK) coronal loops at their foot-points. The coronal part of the loops is fuzzy but what appear to be their footpoints in the transition region down to the photosphere are compact. Despite the morphological similarities, the footpoint emission at 10(exp 5) K is not quantitatively correlated with that at approximately 300 km above the tau (sub 5000) = 1 level, suggesting that the heat transport and therefore magnetic field topology in the intermediate layer is complicated. High resolution imaging observations with continuous temperature coverage are crucially needed.

  14. MAGNETIC PROPERTIES OF SOLAR ACTIVE REGIONS THAT GOVERN LARGE SOLAR FLARES AND ERUPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Toriumi, Shin [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Schrijver, Carolus J. [Lockheed Martin Advanced Technology Center, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Harra, Louise K. [UCL-Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Hudson, Hugh [SUPA School of Physics and Astronomy, University of Glasgow (United Kingdom); Nagashima, Kaori, E-mail: shin.toriumi@nao.ac.jp [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2017-01-01

    Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim of understanding the magnetic properties that govern such flares and eruptions, we systematically survey all flare events with Geostationary Orbiting Environmental Satellite levels of ≥M5.0 within 45° from disk center between 2010 May and 2016 April. These criteria lead to a total of 51 flares from 29 ARs, for which we analyze the observational data obtained by the Solar Dynamics Observatory . More than 80% of the 29 ARs are found to exhibit δ -sunspots, and at least three ARs violate Hale’s polarity rule. The flare durations are approximately proportional to the distance between the two flare ribbons, to the total magnetic flux inside the ribbons, and to the ribbon area. From our study, one of the parameters that clearly determine whether a given flare event is CME-eruptive or not is the ribbon area normalized by the sunspot area, which may indicate that the structural relationship between the flaring region and the entire AR controls CME productivity. AR characterization shows that even X-class events do not require δ -sunspots or strong-field, high-gradient polarity inversion lines. An investigation of historical observational data suggests the possibility that the largest solar ARs, with magnetic flux of 2 × 10{sup 23} Mx, might be able to produce “superflares” with energies of the order of 10{sup 34} erg. The proportionality between the flare durations and magnetic energies is consistent with stellar flare observations, suggesting a common physical background for solar and stellar flares.

  15. Numerical modelling of heat and mass transfer in adsorption solar reactor of ammonia on active carbon

    Science.gov (United States)

    Aroudam, El. H.

    In this paper, we present a modelling of the performance of a reactor of a solar cooling machine based carbon-ammonia activated bed. Hence, for a solar radiation, measured in the Energetic Laboratory of the Faculty of Sciences in Tetouan (northern Morocco), the proposed model computes the temperature distribution, the pressure and the ammonia concentration within the activated carbon bed. The Dubinin-Radushkevich formula is used to compute the ammonia concentration distribution and the daily cycled mass necessary to produce a cooling effect for an ideal machine. The reactor is heated at a maximum temperature during the day and cool at the night. A numerical simulation is carried out employing the recorded solar radiation data measured locally and the daily ambient temperature for the typical clear days. Initially the reactor is at ambient temperature, evaporating pressure; Pev=Pst(Tev=0 ∘C) and maintained at uniform concentration. It is heated successively until the threshold temperature corresponding to the condensing pressure; Pcond=Pst(Tam) (saturation pressure at ambient temperature; in the condenser) and until a maximum temperature at a constant pressure; Pcond. The cooling of the reactor is characterised by a fall of temperature to the minimal values at night corresponding to the end of a daily cycle. We use the mass balance equations as well as energy equation to describe heat and mass transfer inside the medium of three phases. A numerical solution of the obtained non linear equations system based on the implicit finite difference method allows to know all parameters characteristic of the thermodynamic cycle and consider principally the daily evolution of temperature, ammonia concentration for divers positions inside the reactor. The tube diameter of the reactor shows the dependence of the optimum value on meteorological parameters for 1 m2 of collector surface.

  16. Nonlinear techniques for forecasting solar activity directly from its time series

    Science.gov (United States)

    Ashrafi, S.; Roszman, L.; Cooley, J.

    1993-01-01

    This paper presents numerical techniques for constructing nonlinear predictive models to forecast solar flux directly from its time series. This approach makes it possible to extract dynamical in variants of our system without reference to any underlying solar physics. We consider the dynamical evolution of solar activity in a reconstructed phase space that captures the attractor (strange), give a procedure for constructing a predictor of future solar activity, and discuss extraction of dynamical invariants such as Lyapunov exponents and attractor dimension.

  17. Solar rotational cycle in lightning activity in Japan during the 18-19th centuries

    Science.gov (United States)

    Miyahara, Hiroko; Kataoka, Ryuho; Mikami, Takehiko; Zaiki, Masumi; Hirano, Junpei; Yoshimura, Minoru; Aono, Yasuyuki; Iwahashi, Kiyomi

    2018-04-01

    Thunderstorm and cloud activities sometimes show a 27-day period, and this has long been studied to uncover a possible important link to solar rotation. Because the 27-day variations in the solar forcing parameters such as solar ultraviolet and galactic cosmic rays become more prominent when the solar activity is high, it is expected that the signal of the 27-day period in meteorological phenomena may wax and wane according to the changes in the solar activity level. In this study, we examine in detail the intensity variations in the signal of the 27-day solar rotational period in thunder and lightning activity from the 18th to the 19th centuries based on 150-year-long records found in old diaries kept in Japan and discuss their relation with the solar activity levels. Such long records enable us to examine the signals of solar rotation at both high and low solar activity levels. We found that the signal of the solar rotational period in the thunder and lightning activity increases as the solar activity increases. In this study, we also discuss the possibility of the impact of the long-term climatological conditions on the signals of the 27-day period in thunder/lightning activities.

  18. Sun Protection Preferences and Behaviors among Young Adult Males during Maximum Ultraviolet Radiation Exposure Activities

    Science.gov (United States)

    Wickenheiser, Marilyn; Baker, Mary Kate; Gaber, Rikki; Blatt, Hanz; Robinson, June K.

    2013-01-01

    This study explores sun protection attitudes, preferences, and behaviors among young adult males participating in an open-field activity with extreme ultraviolet radiation exposure. Male drum corps members (n = 137) responded to survey questions regarding their behavior and willingness to engage in sun protection and barriers to sunscreen usage. A subset of members (n = 31) participated in cognitive interviews exploring various sunscreen products and intervention techniques. Participants were knowledgeable about health risks and protection benefits regarding sun exposure. Generally, males had positive attitudes and normative beliefs about using sunscreen. A barrier to sunscreen re-application was lack of adequate time to reapply sunscreen during the open field activity. Males preferred a towelette application method, but were unfamiliar with its efficacy and proper use. Thus, they were more likely to use the more familiar sunscreen spray. To increase sun protection behaviors and lower skin cancer risk for males participating in open-field activities, breaks must be allotted every 2 h and have sufficient time to allow sunscreen application. Future development and research into delivery systems that rapidly and evenly apply sunscreen may help lower exposure in this population. PMID:23912201

  19. Sun Protection Preferences and Behaviors among Young Adult Males during Maximum Ultraviolet Radiation Exposure Activities

    Directory of Open Access Journals (Sweden)

    June K. Robinson

    2013-07-01

    Full Text Available This study explores sun protection attitudes, preferences, and behaviors among young adult males participating in an open-field activity with extreme ultraviolet radiation exposure. Male drum corps members (n = 137 responded to survey questions regarding their behavior and willingness to engage in sun protection and barriers to sunscreen usage. A subset of members (n = 31 participated in cognitive interviews exploring various sunscreen products and intervention techniques. Participants were knowledgeable about health risks and protection benefits regarding sun exposure. Generally, males had positive attitudes and normative beliefs about using sunscreen. A barrier to sunscreen re-application was lack of adequate time to reapply sunscreen during the open field activity. Males preferred a towelette application method, but were unfamiliar with its efficacy and proper use. Thus, they were more likely to use the more familiar sunscreen spray. To increase sun protection behaviors and lower skin cancer risk for males participating in open-field activities, breaks must be allotted every 2 h and have sufficient time to allow sunscreen application. Future development and research into delivery systems that rapidly and evenly apply sunscreen may help lower exposure in this population.

  20. Morphology of geomagnetic storms, recorded at Hurbanovo, and its relation to solar activity

    International Nuclear Information System (INIS)

    Ochabova, P.; Psenakova, M.

    1977-01-01

    The morphological structure of geomagnetic storms was investigated using the data on 414 storms, recorded in the years 1949 to 1968 at the Geomagnetic Observatory of Hurbanovo (phi=47.9 deg N, lambda=18.2 deg E). These data also formed a suitable basis for investigating the effect of the solar activity on the characteristic features of storms. The storm-time variation of the geomagnetic field was considered after the Sq-variation had been eliminated. The sets of storms, i.e. 263 storms recorded at a time of high sunspot activity and 151 storms recorded at a time of low activity, were divided into 7 groups, depending on the duration of their initial phase. In 92% of the investigated storms the increase in the horizontal component lasted from 0 to 15 hrs. The effect of the solar activity was markedly reflected in the occurrence of very severe storms, as well as in the maximum decrease in the H-component in the main phase. This can also be seen in the rate at which the storms recover. (author)

  1. THE ACTIVE INTEGRATED CIRCULAR PROCESS – EXPRESSION OF MAXIMUM SYNTHESIS OF SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Done Ioan

    2015-06-01

    Full Text Available "The accelerated pace of economic growth, prompted by the need to ensure reducing disparities between the various countries, has imposed in the last two decades the adoption of sustainable development principles, particularly as a result of the Rio Declaration on Environment and Development (1992 and the UNESCO Declaration in the fall of 1997. In specific literature, in essence, sustainable development is considered "an economic and social process that is characterized by a simultaneous and concerted action at global, regional and local level. Its objective is to provide living conditions both for the present and forth future. Sustainable development “encompasses the economic, ecological, social and political aspects, linked through cultural and spiritual relationships."(Coşea, 2007In Romania, achieving sustainable development is a major, difficult objective, because it must be done in terms of convergence to the demands of the economic, social, cultural and political context of the EU, and in terms of the completion of the transition to a functioning and competitive market economy. In this context, it is imposed the economic competitiveness through reindustrialization and not least, by harnessing the active integrated circular process. Gross value added and profit chain in the structures of active integrated circular process must reflect the interests of the forces involved(employers, employees and the statethereby forming the basis of respect for the correlation between sustainable development, economic growth and increasing national wealth. The elimination or marginalization of certain links in the value chain and profit causes major disruptions or bankruptcy, with direct implications for recognizing and rewarding performance. Essentially, the building of active integrated circular process will determine the maximization of the profit – the foundation of satisfying all economic interests.

  2. Temporal associations of life with solar and geophysical activity

    Directory of Open Access Journals (Sweden)

    T. K. Breus

    Full Text Available In biology, circadian rhythms with a period of one cycle in 20–28 h are known to be ubiquitous and partly endogenous. Rhythms with a frequency lower than one cycle per day are called 'infradian rhythms'. Among them are components with one cycle in about 3.5, 7, 14 and 28 days, the multiseptans, which, like the circadians, must be regarded as a general characteristic of life: they characterize unicells as well as much more differentiated organisms. We hypothesize that heliogeophysical factors other than the solar visible light, held responsible for the evolution of circadian periodicity, underlie the infradian rhythms of biosystems. The periodicities in the solar wind and variations in the interplanetary magnetic field (IMF which are associated with the solar rotation are very similar in length to the biological periodicities. We investigate the temporal relations of variations in solar activity and in biological systems to test associations between events in the IMF, in geomagnetic disturbance, in myocardial infarction and in physiology. By cross-spectral analysis, we also find relations at certain frequencies between changes in human physiology on the one hand, and (1 the vertical component of the induction vector of the IMF, Bz, and (2 a global index of geomagnetic disturbance, Kp, on the other hand. We wish to stimulate interest in these periodicities of both biological systems and geophysical endpoints among physicists and biologists alike, so that problems relevant to clinicians and other biologists, including evolutionists, are eventually solved by their cooperation with the geophysical community.

  3. Active Contour Driven by Local Region Statistics and Maximum A Posteriori Probability for Medical Image Segmentation

    Directory of Open Access Journals (Sweden)

    Xiaoliang Jiang

    2014-01-01

    Full Text Available This paper presents a novel active contour model in a variational level set formulation for simultaneous segmentation and bias field estimation of medical images. An energy function is formulated based on improved Kullback-Leibler distance (KLD with likelihood ratio. According to the additive model of images with intensity inhomogeneity, we characterize the statistics of image intensities belonging to each different object in local regions as Gaussian distributions with different means and variances. Then, we use the Gaussian distribution with bias field as a local region descriptor in level set formulation for segmentation and bias field correction of the images with inhomogeneous intensities. Therefore, image segmentation and bias field estimation are simultaneously achieved by minimizing the level set formulation. Experimental results demonstrate desirable performance of the proposed method for different medical images with weak boundaries and noise.

  4. The relationship between ionospheric temperature, electron density and solar activity

    International Nuclear Information System (INIS)

    McDonald, J.N.; Williams, P.J.S.

    1980-01-01

    In studying the F-region of the ionosphere several authors have concluded that the difference between the electron temperature Tsub(e) and the ion temperature Tsub(i) is related to the electron density N. It was later noted that solar activity (S) was involved and an empirical relationship of the following form was established: Tsub(e)-Tsub(i) = A-BN+CS. The present paper extends this work using day-time data over a four year period. The results are given and discussed. A modified form of the empirical relation is proposed. (U.K.)

  5. The northern annular mode in summer and its relation to solar activity variations in the GISS ModelE

    Science.gov (United States)

    Lee, Jae N.; Hameed, Sultan; Shindell, Drew T.

    2008-03-01

    The northern annular mode (NAM) has been successfully used in several studies to understand the variability of the winter atmosphere and its modulation by solar activity. The variability of summer circulation can also be described by the leading empirical orthogonal function (EOF) of geopotential heights. We compare the annular modes of the summer geopotential heights in the northern hemisphere stratosphere and troposphere in the Goddard Institute for Space Studies (GISS) ModelE with those in the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. In the stratosphere, the summer NAM obtained from NCEP/NCAR reanalysis as well as from the ModelE simulations has the same sign throughout the northern hemisphere, but shows greater variability at low latitudes. The patterns in both analyses are consistent with the interpretation that low NAM conditions represent an enhancement of the seasonal difference between the summer and the annual averages of geopotential height, temperature and velocity distributions, while the reverse holds for high NAM conditions. Composite analysis of high and low NAM cases in both model and observation suggests that the summer stratosphere is more "summer-like" when the solar activity is near a maximum. This means that the zonal easterly wind flow is stronger and the temperature is higher than normal. Thus increased irradiance favors a low summer NAM. A quantitative comparison of the anti-correlation between the NAM and the solar forcing is presented in the model and in the observation, both of which show lower/higher NAM index in solar maximum/minimum conditions. The temperature fluctuations in simulated solar minimum conditions are greater than in solar maximum throughout the summer stratosphere. The summer NAM in the troposphere obtained from NCEP/NCAR reanalysis has a dipolar zonal structure with maximum variability over the Asian monsoon region. The corresponding EOF in ModelE has

  6. Equatorial Ionospheric Anomaly (EIA) and comparison with IRI model during descending phase of solar activity (2005-2009)

    Science.gov (United States)

    Kumar, Sanjay; Singh, A. K.; Lee, Jiyun

    2014-03-01

    The ionospheric variability at equatorial and low latitude region is known to be extreme as compared to mid latitude region. In this study the ionospheric total electron content (TEC), is derived by analyzing dual frequency Global Positioning System (GPS) data recorded at two stations separated by 325 km near the Indian equatorial anomaly region, Varanasi (Geog latitude 25°, 16/ N, longitude 82°, 59/ E, Geomagnetic latitude 16°, 08/ N) and Kanpur (Geog latitude 26°, 18/ N, longitude 80°, 12/ E, Geomagnetic latitude 17°, 18/ N). Specifically, we studied monthly, seasonal and annual variations as well as solar and geomagnetic effects on the equatorial ionospheric anomaly (EIA) during the descending phase of solar activity from 2005 to 2009. It is found that the maximum TEC (EIA) near equatorial anomaly crest yield their maximum values during the equinox months and their minimum values during the summer. Using monthly averaged peak magnitude of TEC, a clear semi-annual variation is seen with two maxima occurring in both spring and autumn. Results also showed the presence of winter anomaly or seasonal anomaly in the EIA crest throughout the period 2005-2009 only except during the deep solar minimum year 2007-2008. The correlation analysis indicate that the variation of EIA crest is more affected by solar activity compared to geomagnetic activity with maximum dependence on the solar EUV flux, which is attributed to direct link of EUV flux on the formation of ionosphere and main agent of the ionization. The statistical mean occurrence of EIA crest in TEC during the year from 2005 to 2009 is found to around 12:54 LT hour and at 21.12° N geographic latitude. The crest of EIA shifts towards lower latitudes and the rate of shift of the crest latitude during this period is found to be 0.87° N/per year. The comparison between IRI models with observation during this period has been made and comparison is poor with increasing solar activity with maximum difference during

  7. Examination into the maximum rotational frequency for an in-plane switched active waveplate device

    International Nuclear Information System (INIS)

    Davidson, A J; Elston, S J; Raynes, E P

    2005-01-01

    An examination of an active waveplate device using a one-dimensional model, giving numerical and analytical results, is presented. The model calculates the director and twist configuration by minimizing the free energy of the system with simple homeotropic boundary conditions. The effect of varying the in-plane electric field in both magnitude and direction is examined, and it is shown that the twist through the cell is constant in time as the field is rotated. As the electric field is rotated, the director field lags behind by an angle which increases as the frequency of the electric field rotation increases. When this angle reaches approximately π/4 the director field no longer follows the electric field in a uniform way. Using mathematical analysis it is shown that the conditions on which the director profile will fail to follow the rotating electric field depend on the frequency of electric field rotation, the magnitude of the electric field, the dielectric anisotropy and the viscosity of the liquid crystal

  8. Solar and terrestrial physics. [effects of solar activities on earth environment

    Science.gov (United States)

    1975-01-01

    The effects of solar radiation on the near space and biomental earth, the upper atmosphere, and the magnetosphere are discussed. Data obtained from the OSO satellites pertaining to the solar cycle variation of extreme ultraviolet (EUV) radiation are analyzed. The effects of solar cycle variation of the characteristics of the solar wind are examined. The fluid mechanics of shock waves and the specific relationship to the characteristics of solar shock waves are investigated. The solar and corpuscular heating of the upper atmosphere is reported based on the findings of the AEROS and NATE experiments. Seasonal variations of the upper atmosphere composition are plotted based on OGO-6 mass spectrometer data.

  9. Solar thermal collectors at design and technology activity days

    OpenAIRE

    Petrina, Darinka

    2016-01-01

    Thesis encompases usage of renewable resources of energy, especially solar energy, which is essential for our future. On one hand, certain ways of exploiting solar energy (with solar cells) have been well established and is included in the Design and technology curriculum, on the other hand however, solar thermal collectors have not been recognized enough in spite of their distribution, applicability and environmentally friendly technology. Consequently thesis emphasizes the usage of solar en...

  10. Frequency dependence of p-mode frequency shifts induced by magnetic activity in Kepler solar-like stars

    Science.gov (United States)

    Salabert, D.; Régulo, C.; Pérez Hernández, F.; García, R. A.

    2018-04-01

    The variations of the frequencies of the low-degree acoustic oscillations in the Sun induced by magnetic activity show a dependence on radial order. The frequency shifts are observed to increase towards higher-order modes to reach a maximum of about 0.8 μHz over the 11-yr solar cycle. A comparable frequency dependence is also measured in two other main sequence solar-like stars, the F-star HD 49933, and the young 1 Gyr-old solar analog KIC 10644253, although with different amplitudes of the shifts of about 2 μHz and 0.5 μHz, respectively. Our objective here is to extend this analysis to stars with different masses, metallicities, and evolutionary stages. From an initial set of 87 Kepler solar-like oscillating stars with known individual p-mode frequencies, we identify five stars showing frequency shifts that can be considered reliable using selection criteria based on Monte Carlo simulations and on the photospheric magnetic activity proxy Sph. The frequency dependence of the frequency shifts of four of these stars could be measured for the l = 0 and l = 1 modes individually. Given the quality of the data, the results could indicate that a physical source of perturbation different from that in the Sun is dominating in this sample of solar-like stars.

  11. Local Times of Galactic Cosmic Ray Intensity Maximum and Minimum in the Diurnal Variation

    Directory of Open Access Journals (Sweden)

    Su Yeon Oh

    2006-06-01

    Full Text Available The Diurnal variation of galactic cosmic ray (GCR flux intensity observed by the ground Neutron Monitor (NM shows a sinusoidal pattern with the amplitude of 1sim 2 % of daily mean. We carried out a statistical study on tendencies of the local times of GCR intensity daily maximum and minimum. To test the influences of the solar activity and the location (cut-off rigidity on the distribution in the local times of maximum and minimum GCR intensity, we have examined the data of 1996 (solar minimum and 2000 (solar maximum at the low-latitude Haleakala (latitude: 20.72 N, cut-off rigidity: 12.91 GeV and the high-latitude Oulu (latitude: 65.05 N, cut-off rigidity: 0.81 GeV NM stations. The most frequent local times of the GCR intensity daily maximum and minimum come later about 2sim3 hours in the solar activity maximum year 2000 than in the solar activity minimum year 1996. Oulu NM station whose cut-off rigidity is smaller has the most frequent local times of the GCR intensity maximum and minimum later by 2sim3 hours from those of Haleakala station. This feature is more evident at the solar maximum. The phase of the daily variation in GCR is dependent upon the interplanetary magnetic field varying with the solar activity and the cut-off rigidity varying with the geographic latitude.

  12. Solar Energy Education. Social studies: activities and teacher's guide. Field test edition

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    Solar energy information is made available to students through classroom instruction by way of the Solar Energy Education teaching manuals. In this manual solar energy, as well as other energy sources like wind power, is introduced by performing school activities in the area of social studies. A glossary of energy related terms is included. (BCS)

  13. Small Coronal Holes Near Active Regions as Sources of Slow Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.-M., E-mail: yi.wang@nrl.navy.mil [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2017-06-01

    We discuss the nature of the small areas of rapidly diverging, open magnetic flux that form in the strong unipolar fields at the peripheries of active regions (ARs), according to coronal extrapolations of photospheric field measurements. Because such regions usually have dark counterparts in extreme-ultraviolet (EUV) images, we refer to them as coronal holes, even when they appear as narrow lanes or contain sunspots. Revisiting previously identified “AR sources” of slow solar wind from 1998 and 1999, we find that they are all associated with EUV coronal holes; the absence of well-defined He i 1083.0 nm counterparts to some of these holes is attributed to the large flux of photoionizing radiation from neighboring AR loops. Examining a number of AR-associated EUV holes during the 2014 activity maximum, we confirm that they are characterized by wind speeds of ∼300–450 km s{sup −1}, O{sup 7+}/O{sup 6+} ratios of ∼0.05–0.4, and footpoint field strengths typically of order 30 G. The close spacing between ARs at sunspot maximum limits the widths of unipolar regions and their embedded holes, while the continual emergence of new flux leads to rapid changes in the hole boundaries. Because of the highly nonradial nature of AR fields, the smaller EUV holes are often masked by the overlying canopy of loops, and may be more visible toward one solar limb than at central meridian. As sunspot activity declines, the AR remnants merge to form much larger, weaker, and longer-lived unipolar regions, which harbor the “classical” coronal holes that produce recurrent high-speed streams.

  14. Lower limit of intensity for the solar activity in microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, P; Iacomo, P Jr; Koppe, E H; dos Santos, P M; Schaal, R E [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica; Blakey, J R [Surrey Univ., Guildford (UK). Dept. of Physics

    1976-01-01

    The active region McMath 10433 has produced various flares and bursts in radio frequency in the beginning of july 1974. This region was scanned countinously in 22.2 GHz with a radio telescope showing a 4 min. arc beam, in various periods of the month. In comparison with the results simultaneously obtained with a normal solar radio telescope, in 7 GHz, it was verified that there is an important explosive activity in lower levels in the limit of detection of an usual patrolling instrument. The morphology of these events, in its progress in the time, is similar to that normaly known, and allowed, the re-interpretation of simple events. A completly new type of event was defined: the fast absorptions. The correlation of events in microwaves with 'SPA' recorded in 'VLF' propagation is also discussed.

  15. Resonance of about-weekly human heart rate rhythm with solar activity change.

    Science.gov (United States)

    Cornelissen, G; Halberg, F; Wendt, H W; Bingham, C; Sothern, R B; Haus, E; Kleitman, E; Kleitman, N; Revilla, M A; Revilla, M; Breus, T K; Pimenov, K; Grigoriev, A E; Mitish, M D; Yatsyk, G V; Syutkina, E V

    1996-12-01

    In several human adults, certain solar activity rhythms may influence an about 7-day rhythm in heart rate. When no about-weekly feature was found in the rate of change in sunspot area, a measure of solar activity, the double amplitude of a circadian heart rate rhythm, approximated by the fit of a 7-day cosine curve, was lower, as was heart rate corresponds to about-weekly features in solar activity and/or relates to a sunspot cycle.

  16. The influence of solar active region evolution on solar wind streams, coronal hole boundaries and geomagnetic storms

    Science.gov (United States)

    Gold, R. E.; Dodson-Prince, H. W.; Hedeman, E. R.; Roelof, E. C.

    1982-01-01

    Solar and interplanetary data are examined, taking into account the identification of the heliographic longitudes of the coronal source regions of high speed solar wind (SW) streams by Nolte and Roelof (1973). Nolte and Roelof have 'mapped' the velocities measured near earth back to the sun using the approximation of constant radial velocity. The 'Carrington carpet' for rotations 1597-1616 is shown in a graph. Coronal sources of high speed streams appear in the form of solid black areas. The contours of the stream sources are laid on 'evolutionary charts' of solar active region histories for the Southern and Northern Hemispheres. Questions regarding the interplay of active regions and solar wind are investigated, giving attention to developments during the years 1973, 1974, and 1975.

  17. How unprecedented a solar minimum was it?

    Science.gov (United States)

    Russell, C T; Jian, L K; Luhmann, J G

    2013-05-01

    The end of the last solar cycle was at least 3 years late, and to date, the new solar cycle has seen mainly weaker activity since the onset of the rising phase toward the new solar maximum. The newspapers now even report when auroras are seen in Norway. This paper is an update of our review paper written during the deepest part of the last solar minimum [1]. We update the records of solar activity and its consequent effects on the interplanetary fields and solar wind density. The arrival of solar minimum allows us to use two techniques that predict sunspot maximum from readings obtained at solar minimum. It is clear that the Sun is still behaving strangely compared to the last few solar minima even though we are well beyond the minimum phase of the cycle 23-24 transition.

  18. Releasable activity and maximum permissible leakage rate within a transport cask of Tehran Research Reactor fuel samples

    Directory of Open Access Journals (Sweden)

    Rezaeian Mahdi

    2015-01-01

    Full Text Available Containment of a transport cask during both normal and accident conditions is important to the health and safety of the public and of the operators. Based on IAEA regulations, releasable activity and maximum permissible volumetric leakage rate within the cask containing fuel samples of Tehran Research Reactor enclosed in an irradiated capsule are calculated. The contributions to the total activity from the four sources of gas, volatile, fines, and corrosion products are treated separately. These calculations are necessary to identify an appropriate leak test that must be performed on the cask and the results can be utilized as the source term for dose evaluation in the safety assessment of the cask.

  19. Development of model of night Venus ionosphere production for low solar activity

    International Nuclear Information System (INIS)

    Samoznaev, L.N.

    1990-01-01

    A two-dimensional model of night ionosphere production, where action of two probable sources of its production (ionization by overheated electrons and horizontal ion transfer from a day side) takes into account, is tested applicably to the low solar activity on the basis of data on radioeclipses of Venera-9, -10 and Venera-15, -16 satellites. Comparison of experimental data with calculational ones testifies to the first sources mentioned above, while the second one together with photoionization contributes only to the regions closing to the planet terminator and causes regular decrease of electron concentration in maximum of the basic layer of the ionosphere together with the growth of the Sun zenith angle in the range from 90 deg to 110 deg

  20. Comparison of experimental slant electron content and IRI model for moderate solar activity conditions

    International Nuclear Information System (INIS)

    Cabrera, M.A.; Ezquer, R.G.; Mosert, M.; Jadur, C.A.

    2002-01-01

    The International Reference Ionosphere model only gives the vertical electron content (VTEC). In this paper the slant electron content (SEC) for the ATS 6 satellite - Palehua (21.4 deg. N, 201.9 deg. E) radio signal path for a middle solar activity year is calculated. To this end, IRI model is used to obtain the electron density at different points of the signal path. Equinoxes and solstices are considered. Measurements obtained with Faraday rotation technique at Palehua are compared with the modelled values. Although overestimation was observed for night hours, the results show good SEC predictions for several hours at period of maximum ionisation, suggesting that would be possible to model the STEC using IRI. (author)

  1. Feasibility of active solar water heating systems with evacuated tube collector at different operational water temperatures

    International Nuclear Information System (INIS)

    Mazarrón, Fernando R.; Porras-Prieto, Carlos Javier; García, José Luis; Benavente, Rosa María

    2016-01-01

    Highlights: • Analysis of the feasibility of an active solar water-heating system. • Profitability decreases as the required water temperature increases. • The number of collectors that maximizes profitability depends on the required temperature. • Investment in a properly sized system generates savings between 23% and 15%. • Fuel consumption can be reduced by 70%. - Abstract: With rapid advancements in society, higher water temperatures are needed in a number of applications. The demand for hot water presents a great variability with water required at different temperatures. In this study, the design, installation, and evaluation of a solar water heating system with evacuated tube collector and active circulation has been carried out. The main objective is to analyze how the required tank water temperature affects the useful energy that the system is capable of delivering, and consequently its profitability. The results show how the energy that is collected and delivered to the tank decreases with increasing the required temperature due to a lower performance of the collector and losses in the pipes. The annual system efficiency reaches average values of 66%, 64%, 61%, 56%, and 55% for required temperatures of 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C. As a result, profitability decreases as temperature increases. The useful energy, and therefore the profitability, will decrease if the demand is not distributed throughout the day or focused on the end of the day. The system’s profitability was determined in two cases: considering maximum profitability of the system, assuming 100% utilization of useful energy (scenario 1); assuming a particular demand, considering that on many days all the useful energy the system can supply is not used (scenario 2). The analysis shows that through proper sizing of the system, optimizing the number of solar collectors, the investment in the solar system can be profitable with similar profitability values in the two

  2. Theoretical Calculations of the Seasonal and Solar Activity Variations for Ionospheric Collision Frequency and Debye Length over Baghdad City

    Directory of Open Access Journals (Sweden)

    Ali Hussein Ni'ma

    2017-03-01

    Full Text Available In this study, two important ionospheric factors have been calculated, the collision frequency of electron and Deby length for a height range from 80 Km to a height approaching the maximum height of the F2 region of the ionosphere above the Earth's surface. Both above factors have been calculated for two different levels of solar activity and for two seasons (winter and summer. Also, six months were adopted for every level of solar activity and season. The estimation of collision frequency of electron is depends on the contribution of neutral constituents and ions. Three neutral atmospheric gases have been adopted to calculate the collision frequency, Molecular and atomic oxygen O2 and O respectively and molecular nitrogen N2, as well as the singly charged ions were taken into account in calculation.

  3. A study of solar magnetic fields below the surface, at the surface, and in the solar atmosphere - understanding the cause of major solar activity

    Science.gov (United States)

    Chintzoglou, Georgios

    2016-04-01

    Magnetic fields govern all aspects of solar activity from the 11-year solar cycle to the most energetic events in the solar system, such as solar flares and Coronal Mass Ejections (CMEs). As seen on the surface of the sun, this activity emanates from localized concentrations of magnetic fields emerging sporadically from the solar interior. These locations are called solar Active Regions (ARs). However, the fundamental processes regarding the origin, emergence and evolution of solar magnetic fields as well as the generation of solar activity are largely unknown or remain controversial. In this dissertation, multiple important issues regarding solar magnetism and activities are addressed, based on advanced observations obtained by AIA and HMI instruments aboard the SDO spacecraft. First, this work investigates the formation of coronal magnetic flux ropes (MFRs), structures associated with major solar activity such as CMEs. In the past, several theories have been proposed to explain the cause of this major activity, which can be categorized in two contrasting groups (a) the MFR is formed in the eruption, and (b) the MFR pre-exists the eruption. This remains a topic of heated debate in modern solar physics. This dissertation provides a complete treatment of the role of MFRs from their genesis all the way to their eruption and even destruction. The study has uncovered the pre-existence of two weakly twisted MFRs, which formed during confined flaring 12 hours before their associated CMEs. Thus, it provides unambiguous evidence for MFRs truly existing before the CME eruptions, resolving the pre-existing MFR controversy. Second, this dissertation addresses the 3-D magnetic structure of complex emerging ARs. In ARs the photospheric fields might show all aspects of complexity, from simple bipolar regions to extremely complex multi-polar surface magnetic distributions. In this thesis, we introduce a novel technique to infer the subphotospheric configuration of emerging

  4. SIGN SINGULARITY AND FLARES IN SOLAR ACTIVE REGION NOAA 11158

    Energy Technology Data Exchange (ETDEWEB)

    Sorriso-Valvo, L.; De Vita, G. [IMIP-CNR, U.O.S. LICRYL di Cosenza, Ponte P. Bucci, Cubo 31C, I-87036 Rende (Italy); Kazachenko, M. D.; Krucker, S.; Welsch, B. T.; Fisher, G. H. [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley 94720, California (United States); Primavera, L.; Servidio, S.; Lepreti, F.; Carbone, V. [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, Cubo 31C, I-87036 Rende (Italy); Vecchio, A., E-mail: sorriso@fis.unical.it [INGV, Sede di Cosenza, Ponte P. Bucci, Cubo 30C, I-87036 Rende (Italy)

    2015-03-01

    Solar Active Region NOAA 11158 has hosted a number of strong flares, including one X2.2 event. The complexity of current density and current helicity are studied through cancellation analysis of their sign-singular measure, which features power-law scaling. Spectral analysis is also performed, revealing the presence of two separate scaling ranges with different spectral index. The time evolution of parameters is discussed. Sudden changes of the cancellation exponents at the time of large flares and the presence of correlation with Extreme-Ultra-Violet and X-ray flux suggest that eruption of large flares can be linked to the small-scale properties of the current structures.

  5. VTEC behavior in the American sector during high solar activity

    CERN Document Server

    Ezquer, R G; Brunini, C; Conicet; Meza, A; Mosert, M; Radicella, S M

    2002-01-01

    The behavior of the vertical total electron content (VTEC) obtained from GPS signals received during the high solar activity year 1999 at stations placed in the American sector, is reported. The considered latitude range extends from 18.4 to -64.7 and the longitude ranges from 281.3 to 297.7. Median, lower and upper quartiles are used to specify variability, because they have the advantage of being less affected by large deviations that can occur during magnetic storms. The results show that the VTEC values corresponding to equinox are greater than those of solstice and that, the highest VTEC values are observed at low latitude stations. In general, the variability during daylight hours is about 30% of median or less, and that observed for nighttime hours is greater than the mentioned percentage, particularly at last hours of the night near the northern peak of the equatorial anomaly.

  6. VTEC behavior in the American sector during high solar activity

    International Nuclear Information System (INIS)

    Ezquer, R.G.; Brunini, C.; Meza, A.; Azpilicueta, F.; Mosert, M.; Radicella, S.M.

    2003-01-01

    The behavior of the vertical total electron content (VTEC) obtained from GPS signals received during the high solar activity year 1999 at stations placed in the American sector, is reported. The considered latitude range extends from 18.4 to -64.7 and the longitude ranges from 281.3 to 297.7. Median, lower and upper quartiles are used to specify variability, because they have the advantage of being less affected by large deviations that can occur during magnetic storms. The results show that the VTEC values corresponding to equinox are greater than those of solstice and that, the highest VTEC values are observed at low latitude stations. In general, the variability during daylight hours is about 30% of median or less, and that observed for nighttime hours is greater than the mentioned percentage, particularly at last hours of the night near the northern peak of the equatorial anomaly. (author)

  7. The inconstant solar constant

    International Nuclear Information System (INIS)

    Willson, R.C.; Hudson, H.

    1984-01-01

    The Active Cavity Radiometer Irradiance Monitor (ACRIM) of the Solar Maximum Mission satellite measures the radiant power emitted by the sun in the direction of the earth and has worked flawlessly since 1980. The main motivation for ACRIM's use to measure the solar constant is the determination of the extent to which this quantity's variations affect earth weather and climate. Data from the solar minimum of 1986-1987 is eagerly anticipated, with a view to the possible presence of a solar cycle variation in addition to that caused directly by sunspots

  8. Multifractality as a Measure of Complexity in Solar Flare Activity

    Science.gov (United States)

    Sen, Asok K.

    2007-03-01

    In this paper we use the notion of multifractality to describe the complexity in H α flare activity during the solar cycles 21, 22, and 23. Both northern and southern hemisphere flare indices are analyzed. Multifractal behavior of the flare activity is characterized by calculating the singularity spectrum of the daily flare index time series in terms of the Hölder exponent. The broadness of the singularity spectrum gives a measure of the degree of multifractality or complexity in the flare index data. The broader the spectrum, the richer and more complex is the structure with a higher degree of multifractality. Using this broadness measure, complexity in the flare index data is compared between the northern and southern hemispheres in each of the three cycles, and among the three cycles in each of the two hemispheres. Other parameters of the singularity spectrum can also provide information about the fractal properties of the flare index data. For instance, an asymmetry to the left or right in the singularity spectrum indicates a dominance of high or low fractal exponents, respectively, reflecting a relative abundance of large or small fluctuations in the total energy emitted by the flares. Our results reveal that in the even (22nd) cycle the singularity spectra are very similar for the northern and southern hemispheres, whereas in the odd cycles (21st and 23rd) they differ significantly. In particular, we find that in cycle 21, the northern hemisphere flare index data have higher complexity than its southern counterpart, with an opposite pattern prevailing in cycle 23. Furthermore, small-scale fluctuations in the flare index time series are predominant in the northern hemisphere in the 21st cycle and are predominant in the southern hemisphere in the 23rd cycle. Based on these findings one might suggest that, from cycle to cycle, there exists a smooth switching between the northern and southern hemispheres in the multifractality of the flaring process. This new

  9. Solar Power and Solar Fuels Synthesis Report. Technology, market and research activities 2006-2011

    Energy Technology Data Exchange (ETDEWEB)

    Ridell, Bengt; Nilsson, Ronny; Rehnlund, Bjoern [Grontmij, Stockholm (Sweden); Kasemo, Bengt [Chalmers Univ. of Technology, Goeteborg (Sweden)

    2012-11-01

    The objectives of the synthesis is to survey the situation and give an accumulated and concentrated knowledge about status, needs and opportunities for Swedish research and Swedish industry within the area of solar power and solar fuels, to be used for prioritisation of further efforts. The synthesis shall identify strengths and weaknesses in areas fundamental for development of solar power and solar fuels, focused on the development in Sweden, but in an international context. The synthesis shall also cover proposals for future Swedish research efforts and organisation of future Swedish research programs.

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

    Science.gov (United States)

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

    2017-09-01

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

  11. Development of a new fast shower maximum detector based on microchannel plates photomultipliers (MCP-PMT) as an active element

    Energy Technology Data Exchange (ETDEWEB)

    Ronzhin, A., E-mail: ronzhin@fnal.gov [Fermilab, Batavia, IL 60510 (United States); Los, S.; Ramberg, E. [Fermilab, Batavia, IL 60510 (United States); Spiropulu, M.; Apresyan, A.; Xie, S. [California Institute of Technology, Pasadena, CA (United States); Kim, H. [University of Chicago, Chicago, IL 60637 (United States); Zatserklyaniy, A. [University of California, Santa Cruz, CA (United States)

    2014-09-21

    One possibility to make a fast and radiation resistant shower maximum (SM) detector is to use a secondary emitter as an active element. We present below test beam results, obtained with different types of photodetectors based on microchannel plates (MCPs) as the secondary emitter. We performed the measurements at the Fermilab Test Beam Facility with 120 GeV proton beam and 12 GeV and 32 GeV secondary beams. The goal of the measurement with 120 GeV protons was to determine time resolution for minimum ionizing particles (MIPs). The SM time resolution we obtained for this new type of detector is at the level of 20–30 ps. We estimate that a significant contribution to the detector response originates from secondary emission of the MCP. This work can be considered as the first step in building a new type of calorimeter based on this principle.

  12. EVOLUTION OF MAGNETIC HELICITY AND ENERGY SPECTRA OF SOLAR ACTIVE REGIONS

    International Nuclear Information System (INIS)

    Zhang, Hongqi; Brandenburg, Axel; Sokoloff, D. D.

    2016-01-01

    We adopt an isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field to estimate the magnetic energy and helicity spectra as well as current helicity spectra of two individual active regions (NOAA 11158 and NOAA 11515) and the change of the spectral indices during their development as well as during the solar cycle. The departure of the spectral indices of magnetic energy and current helicity from 5/3 are analyzed, and it is found that it is lower than the spectral index of the magnetic energy spectrum. Furthermore, the fractional magnetic helicity tends to increase when the scale of the energy-carrying magnetic structures increases. The magnetic helicity of NOAA 11515 violates the expected hemispheric sign rule, which is interpreted as an effect of enhanced field strengths at scales larger than 30–60 Mm with opposite signs of helicity. This is consistent with the general cycle dependence, which shows that around the solar maximum the magnetic energy and helicity spectra are steeper, emphasizing the large-scale field

  13. EVOLUTION OF MAGNETIC HELICITY AND ENERGY SPECTRA OF SOLAR ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongqi [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Brandenburg, Axel [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden); Sokoloff, D. D., E-mail: hzhang@bao.ac.cn [Department of Physics, Moscow University, 119992 Moscow (Russian Federation)

    2016-03-10

    We adopt an isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field to estimate the magnetic energy and helicity spectra as well as current helicity spectra of two individual active regions (NOAA 11158 and NOAA 11515) and the change of the spectral indices during their development as well as during the solar cycle. The departure of the spectral indices of magnetic energy and current helicity from 5/3 are analyzed, and it is found that it is lower than the spectral index of the magnetic energy spectrum. Furthermore, the fractional magnetic helicity tends to increase when the scale of the energy-carrying magnetic structures increases. The magnetic helicity of NOAA 11515 violates the expected hemispheric sign rule, which is interpreted as an effect of enhanced field strengths at scales larger than 30–60 Mm with opposite signs of helicity. This is consistent with the general cycle dependence, which shows that around the solar maximum the magnetic energy and helicity spectra are steeper, emphasizing the large-scale field.

  14. Sun in the Epoch ``LOWERED'' Solar Activity: the Comparative Analysis of the Current 24 Solar Cycle and Past Authentic Low Cycles

    Science.gov (United States)

    Vitaly, Ishkov

    A reliable series of the relative numbers of sunspots (14 solar cycles ‒ 165 years) it leads to the only scenario of solar activity cycles - to the alternation of epochs of “increased” (18 ‒ 22 cycles of solar activity) and “lowered” (12 ‒ 16 and 24 ‒ ...) solar activity with the periods of solar magnetic field reconstruction in solar zone of the sunspots formation (11, 12, 23) from one epoch to another. The regime of the produce of magnetic field significantly changes in these periods, providing to the subsequent 5 cycles the stable conditions of solar activity. Space solar research made it possible to sufficiently fully investigate characteristics and parameters of the solar cycles for the epoch of “increased” (20 ‒ 22 cycles) solar activity and period of the reconstruction (22 ‒ 23 cycles) to the epoch of “lowered” solar activity (24 ‒ ... cycles). In this scenario 24 solar cycle is the first solar cycle of the second epoch of “lowered” solar activity. Therefore his development and characteristics roughly must be described in the context of the low solar cycles development (12, 14, and 16). In the current solar cycle the sunspot-forming activity is lowered, the average areas of the sunspot groups correspond to values for epoch of “lowered “solar activity, average magnetic field in the umbra of sunspots was reduced approximately to 700 gauss, and for this time was observed only 4 very large sunspot groups (≥1500 mvh). Flare activity substantially was lowered: for the time of the current solar cycle development it was occurrence of M-class flares M - 368, class X - 32, from which only 2 solar flares of class X> 5. Solar proton events are observed predominantly small intensity; but only 5 from them were the intensity of ≥100 pfu (S2) and 4 - ≥1000 pfu (S3). The first five years of the 24 cycle evolution confirm this assumption and the possibility to give the qualitative forecast of his evolution and development of the

  15. Helio-Geomagnetic Activity and the Time Distribution of Myocardial Infractions during the Solar Cycle 23 (1997-2007). A Preliminary Study based on a Greek Hospital Data

    Science.gov (United States)

    Moussas, X.; Preka-Papadema, P.; Apostolou, Th.; Katsavrias, Ch.; Theodoropoulou, A.; Papadima, Th.

    2010-01-01

    We present the time distribution of a large number (7798) of Myocardial Infractions (MI) recorded at the General Hospital `St. Panteleimon' of the city of Nikea (in Piraeus, Greece), during time interval 1997-2007. This data set consisted of 5160 NON-STEACS (non-ST) and 2638 STEACS (ST) infractions are examined along with the monthly numbers of solar flares and Coronal Mass Ejections (CMEs), solar wind parameters and the geomagnetic activity (Dst geomagnetic index and other). The mean monthly value of ST and non-ST events is 20 and 40 respectively. The maximum monthly value of non-ST events (72 and 73) are recorded in October 2002 and January 2003, as well as the one of ST events (32), while solar maximum, recorded in November 2002. This time interval is characterized by magnetic storms from August 2002 peaked in October 2002 and ended in February 2003. It is noticeable that August 2002 corresponds to the solar maximum of CMEs and strong solar flares monthly values. The maximum monthly value of ST events (40) is recorded in November 2005 almost simultaneously with a sudden absence of solar flares (October 2005). Increased values have been recorded during a period of extreme solar events of October-November 2003 and January-March 2005. It seems from this extensive statistical study that there is an association between the monthly values of MI and of CMEs; the non-ST MI shows a better association with CMEs. Moreover, the MI yearly distribution is in accordance with the time distribution of magnetic storms (number and duration). The non-ST distribution is also affected by intense magnetic storms.

  16. The Influence of Solar Activity on the Rainfall over India: Cycle-to ...

    Indian Academy of Sciences (India)

    The Influence of Solar Activity on the Rainfall over India: Cycle-to-Cycle Variations. K. M. Hiremath. Indian Institute of Astrophysics, Bangalore 560 034, India. e-mail: hiremath@iiap.res.in. Abstract. We use 130 years data for studying correlative effects due to solar cycle and activity phenomena on the occurrence of rainfall ...

  17. Solar Energy Education. Humanities: activities and teacher's guide. Field test edition

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    Activities are outlined to introduce students to information on solar energy while performing ordinary classroom work. In this teaching manual solar energy is integrated with the humanities. The activities include such things as stories, newspapers, writing assignments, and art and musical presentations all filled with energy related terms. An energy glossary is provided. (BCS)

  18. Erratum: Correction to: Solar Radius at Subterahertz Frequencies and Its Relation to Solar Activity

    Science.gov (United States)

    Menezes, Fabian; Valio, Adriana

    2018-06-01

    Correction to: Solar Phys (2017) 292:195 https://doi.org/10.1007/s11207-017-1216-y In this article we forgot to acknowledge the financial support for operation of the Solar Submillimeter Telescope (SST) from FAPESP (Proc. #2013/24155-3) and AFOSR Grant #FA9550-16-1-0072. The authors apologize for this negligence.

  19. Mesospheric Na Variability and Dependence on Geomagnetic and Solar Activity over Arecibo

    Science.gov (United States)

    Jain, K.; Raizada, S.; Brum, C. G. M.

    2017-12-01

    The Sodium (Na) resonance lidars located at the Arecibo Observatory offer an excellent opportunity to study the mesosphere/lower thermosphere(MLT) region. Different metals like Fe, Mg, Na, K, Ca and their ions are deposited in the 80 - 120 km altitude range due to the ablation of meteors caused by frictional heating during their entry into the Earth's atmosphere. We present an investigation of the neutral mesospheric Na atom layers over Arecibo. Data on the Na concentrations was collected using a resonance lidar tuned to the of Na wavelength at 589 nm. This wavelength is achieved with a dye-laser pumped by the second harmonic (532 nm) generated from a state-of-the-art commercial Nd:YAG laser. The backscattered signal is received on a 0.8 m (diameter) Cassegrain telescope. The study is based on this data acquired from 1998-2017 and its relation to variations in geomagnetic and solar conditions. We also investigate seasonal and long term trends in the data. The nightly-averaged altitude profiles were modeled as Gaussian curves. From this modeled data we obtain parameters such as the peak, abundance, centroid and width of the main Na layer. Preliminary results show that the Na abundance is more sensitive to changes in geomagnetic and solar variations as compared to the width and centroid height. The seasonal variation exhibits higher peak densities during the local summer and has a secondary maximum during the winter [as shown in the attached figure]. Our analysis demonstrates a decrease in the peak and the abundance of Na atoms with the increase of solar and geomagnetic activity.

  20. Solar-cosmic-ray variability

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1976-01-01

    The maximum flux of particles from solar events that should be considered in designing the shielding for a space habitation is discussed. The activities of various radionuclides measured in the top few centimeters of lunar rocks are used to examine the variability of solar cosmic ray fluxes over the last five million years. 10 references

  1. Discrimination between preseismic electromagnetic anomalies and solar activity effects

    Science.gov (United States)

    Koulouras, Gr; Balasis, G.; Kontakos, K.; Ruzhin, Y.; Avgoustis, G.; Kavouras, D.; Nomicos, C.

    2009-04-01

    Laboratory studies suggest that electromagnetic emissions in a wide frequency spectrum ranging from kHz to very high MHz frequencies are produced by the opening of microcracks, with the MHz radiation appearing earlier than the kHz radiation. Earthquakes are large-scale fracture phenomena in the Earth's heterogeneous crust. Thus, the radiated kHz-MHz electromagnetic emissions are detectable not only at laboratory but also at geological scale. Clear MHz-to-kHz electromagnetic anomalies have been systematically detected over periods ranging from a few days to a few hours prior to recent destructive earthquakes in Greece. We bear in mind that whether electromagnetic precursors to earthquakes exist is an important question not only for earthquake prediction but mainly for understanding the physical processes of earthquake generation. An open question in this field of research is the classification of a detected electromagnetic anomaly as a pre-seismic signal associated to earthquake occurrence. Indeed, electromagnetic fluctuations in the frequency range of MHz are known to related to a few sources, i.e., they might be atmospheric noise (due to lightning), man-made composite noise, solar-terrestrial noise (resulting from the Sun-solar wind-magnetosphere-ionosphere-Earth's surface chain) or cosmic noise, and finally, lithospheric effect, namely pre-seismic activity. We focus on this point. We suggest that if a combination of detected kHz and MHz electromagnetic anomalies satisfies the herein presented set of criteria these anomalies could be considered as candidate precursory phenomena of an impending earthquake.

  2. Magnetic Properties of Solar Active Regions that Govern Large Solar Flares and Eruptions

    Science.gov (United States)

    Toriumi, Shin; Schrijver, Carolus J.; Harra, Louise; Hudson, Hugh S.; Nagashima, Kaori

    2017-08-01

    Strong flares and CMEs are often produced from active regions (ARs). In order to better understand the magnetic properties and evolutions of such ARs, we conducted statistical investigations on the SDO/HMI and AIA data of all flare events with GOES levels >M5.0 within 45 deg from the disk center for 6 years from May 2010 (from the beginning to the declining phase of solar cycle 24). Out of the total of 51 flares from 29 ARs, more than 80% have delta-sunspots and about 15% violate Hale’s polarity rule. We obtained several key findings including (1) the flare duration is linearly proportional to the separation of the flare ribbons (i.e., scale of reconnecting magnetic fields) and (2) CME-eruptive events have smaller sunspot areas. Depending on the magnetic properties, flaring ARs can be categorized into several groups, such as spot-spot, in which a highly-sheared polarity inversion line is formed between two large sunspots, and spot-satellite, where a newly-emerging flux next to a mature sunspot triggers a compact flare event. These results point to the possibility that magnetic structures of the ARs determine the characteristics of flares and CMEs. In the presentation, we will also show new results from the systematic flux emergence simulations of delta-sunspot formation and discuss the evolution processes of flaring ARs.

  3. The role of activity complexes in the distribution of solar magnetic fields.

    Science.gov (United States)

    García de La Rosa, J. I.; Reyes, R. C.

    Using published data on the large-scale distribution of solar activity, the authors conclude that the longlived coronal holes are formed and maintained by the unbalanced magnetic flux which developes at both extremes of the complexes of activity.

  4. Performance Comparison between ĆUK and SEPIC Converters for Maximum Power Point Tracking Using Incremental Conductance Technique in Solar Power Applications

    OpenAIRE

    James Dunia; Bakari M. M. Mwinyiwiwa

    2013-01-01

    Photovoltaic (PV) energy is one of the most important energy resources since it is clean, pollution free, and endless. Maximum Power Point Tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic output power, irrespective the variations of temperature and radiation conditions. This paper presents a comparison between Ćuk and SEPIC converter in maximum power point tracking (MPPT) of photovoltaic (PV) system. In the paper, advantages and disadvantages of both converter...

  5. Ionospheric F2-Layer Semi-Annual Variation in Middle Latitude by Solar Activity

    Directory of Open Access Journals (Sweden)

    Yoon-Kyung Park

    2010-12-01

    Full Text Available We examine the ionospheric F2-layer electron density variation by solar activity in middle latitude by using foF2 observed at the Kokubunji ionosonde station in Japan for the period from 1997 to 2008. The semi-annual variation of foF2 shows obviously in high solar activity (2000-2002 than low solar activity (2006-2008. It seems that variation of geomagnetic activity by solar activity influences on the semi-annual variation of the ionospheric F2-layer electron density. According to the Lomb-Scargle periodogram analysis of foF2 and Ap index, interplanetary magnetic field (IMF Bs (IMF Bz <0 component, solar wind speed, solar wind number density and flow pressure which influence the geomagnetic activity, we examine how the geomagnetic activity affects the ionospheric F2-layer electron density variation. We find that the semi-annual variation of daily foF2, Ap index and IMF Bs appear clearly during the high solar activity. It suggests that the semi-annual variation of geomagnetic activity, caused by Russell-McPherron effect, contributes greatly to the ionospheric F2-layer semi-annual electron density variation, except dynamical effects in the thermosphere.

  6. The active thermal solar; Le solaire thermique actif

    Energy Technology Data Exchange (ETDEWEB)

    Bedel, St.; Salomon, Th.

    2000-05-01

    This information paper recalls the different types of solar cells and their operating. It presents the possible utilizations for the buildings heating (air and water systems) and for the water heating in the residential houses (also for the heating of swimming pools) and the collective buildings. The drying of agricultural products and the solar cooling are also discussed. (A.L.B.)

  7. Solar Energy Education. Renewable energy activities for chemistry and physics

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Information on renewable energy sources is provided for students in this teachers' guide. With the chemistry and physics student in mind, solar energy topics such as absorber plate coatings for solar collectors and energy collection and storage methods are studied. (BCS)

  8. Influence of geomagnetic activity and atmospheric pressure on human arterial pressure during the solar cycle 24

    Science.gov (United States)

    Azcárate, T.; Mendoza, B.; Levi, J. R.

    2016-11-01

    We performed a study of the systolic (SBP) and diastolic (DBP) arterial blood pressure behavior under natural variables such as the atmospheric pressure (AtmP) and the horizontal geomagnetic field component (H). We worked with a sample of 304 healthy normotense volunteers, 152 men and 152 women, with ages between 18 and 84 years in Mexico City during the period 2008-2014, corresponding to the minimum, ascending and maximum phases of the solar cycle 24. The data was divided by gender, age and day/night cycle. We studied the time series using three methods: Correlations, bivariate and superposed epochs (within a window of three days around the day of occurrence of a geomagnetic storm) analysis, between the SBP and DBP and the natural variables (AtmP and H). The correlation analysis indicated correlation between the SBP and DBP and AtmP and H, being the largest during the night. Furthermore, the correlation and bivariate analysis showed that the largest correlations are between the SBP and DBP and the AtmP. The superposed epoch analysis found that the largest number of significant SBP and DBP changes occurred for women. Finally, the blood pressure changes are larger during the solar minimum and ascending solar cycle phases than during the solar maximum; the storms of the minimum were more intense than those of the maximum and this could be the reason of behavior of the blood pressure changes along the solar cycle.

  9. Social networks, leisure activities and maximum tongue pressure: cross-sectional associations in the Nagasaki Islands Study.

    Science.gov (United States)

    Nagayoshi, Mako; Higashi, Miho; Takamura, Noboru; Tamai, Mami; Koyamatsu, Jun; Yamanashi, Hirotomo; Kadota, Koichiro; Sato, Shimpei; Kawashiri, Shin-Ya; Koyama, Zenya; Saito, Toshiyuki; Maeda, Takahiro

    2017-12-06

    Social environment is often associated with health outcomes, but epidemiological evidence for its effect on oral frailty, a potential risk factor for aspiration, is sparse. This study aimed to assess the association between social environment and tongue pressure, as an important measure of oral function. The study focused on family structure, social networks both with and beyond neighbours, and participation in leisure activities. A population-based cross-sectional study. Annual health check-ups in a rural community in Japan. A total of 1982 participants, all over 40 years old. Anyone with missing data for the main outcome (n=14) was excluded. Tongue pressure was measured three times, and the maximum tongue pressure was used for analysis. A multivariable adjusted regression model was used to calculate parameter estimates (B) for tongue pressure. Having a social network involving neighbours (B=2.43, P=0.0001) and taking part in leisure activities (B=1.58, P=0.005) were independently associated with higher tongue pressure, but there was no link with social networks beyond neighbours (B=0.23, P=0.77). Sex-specific analyses showed that for men, having a partner was associated with higher tongue pressure, independent of the number of people in the household (B=2.26, P=0.01), but there was no association among women (B=-0.24, P=0.72; P-interaction=0.059). Having a social network involving neighbours and taking part in leisure activities were independently associated with higher tongue pressure. Marital status may be an important factor in higher tongue pressure in men. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Breathing of heliospheric structures triggered by the solar-cycle activity

    Directory of Open Access Journals (Sweden)

    K. Scherer

    Full Text Available Solar wind ram pressure variations occuring within the solar activity cycle are communicated to the outer heliosphere as complicated time-variabilities, but repeating its typical form with the activity period of about 11 years. At outer heliospheric regions, the main surviving solar cycle feature is a periodic variation of the solar wind dynamical pressure or momentum flow, as clearly recognized by observations of the VOYAGER-1/2 space probes. This long-periodic variation of the solar wind dynamical pressure is modeled here through application of appropriately time-dependent inner boundary conditions within our multifluid code to describe the solar wind – interstellar medium interaction. As we can show, it takes several solar cycles until the heliospheric structures adapt to an average location about which they carry out a periodic breathing, however, lagged in phase with respect to the solar cycle. The dynamically active heliosphere behaves differently from a static heliosphere and especially shows a historic hysteresis in the sense that the shock structures move out to larger distances than explained by the average ram pressure. Obviously, additional energies are pumped into the heliosheath by means of density and pressure waves which are excited. These waves travel outwards through the interface from the termination shock towards the bow shock. Depending on longitude, the heliospheric sheath region memorizes 2–3 (upwind and up to 6–7 (downwind preceding solar activity cycles, i.e. the cycle-induced waves need corresponding travel times for the passage over the heliosheath. Within our multifluid code we also adequately describe the solar cycle variations in the energy distributions of anomalous and galactic cosmic rays, respectively. According to these results the distribution of these high energetic species cannot be correctly described on the basis of the actually prevailing solar wind conditions.

    Key words. Interplanetary

  11. Complex active regions as the main source of extreme and large solar proton events

    Science.gov (United States)

    Ishkov, V. N.

    2013-12-01

    A study of solar proton sources indicated that solar flare events responsible for ≥2000 pfu proton fluxes mostly occur in complex active regions (CARs), i.e., in transition structures between active regions and activity complexes. Different classes of similar structures and their relation to solar proton events (SPEs) and evolution, depending on the origination conditions, are considered. Arguments in favor of the fact that sunspot groups with extreme dimensions are CARs are presented. An analysis of the flare activity in a CAR resulted in the detection of "physical" boundaries, which separate magnetic structures of the same polarity and are responsible for the independent development of each structure.

  12. Empirically modelled Pc3 activity based on solar wind parameters

    Directory of Open Access Journals (Sweden)

    B. Heilig

    2010-09-01

    Full Text Available It is known that under certain solar wind (SW/interplanetary magnetic field (IMF conditions (e.g. high SW speed, low cone angle the occurrence of ground-level Pc3–4 pulsations is more likely. In this paper we demonstrate that in the event of anomalously low SW particle density, Pc3 activity is extremely low regardless of otherwise favourable SW speed and cone angle. We re-investigate the SW control of Pc3 pulsation activity through a statistical analysis and two empirical models with emphasis on the influence of SW density on Pc3 activity. We utilise SW and IMF measurements from the OMNI project and ground-based magnetometer measurements from the MM100 array to relate SW and IMF measurements to the occurrence of Pc3 activity. Multiple linear regression and artificial neural network models are used in iterative processes in order to identify sets of SW-based input parameters, which optimally reproduce a set of Pc3 activity data. The inclusion of SW density in the parameter set significantly improves the models. Not only the density itself, but other density related parameters, such as the dynamic pressure of the SW, or the standoff distance of the magnetopause work equally well in the model. The disappearance of Pc3s during low-density events can have at least four reasons according to the existing upstream wave theory: 1. Pausing the ion-cyclotron resonance that generates the upstream ultra low frequency waves in the absence of protons, 2. Weakening of the bow shock that implies less efficient reflection, 3. The SW becomes sub-Alfvénic and hence it is not able to sweep back the waves propagating upstream with the Alfvén-speed, and 4. The increase of the standoff distance of the magnetopause (and of the bow shock. Although the models cannot account for the lack of Pc3s during intervals when the SW density is extremely low, the resulting sets of optimal model inputs support the generation of mid latitude Pc3 activity predominantly through

  13. Experimental study on solar-powered adsorption refrigeration cycle with activated alumina and activated carbon as adsorbent

    Directory of Open Access Journals (Sweden)

    Himsar Ambarita

    2016-03-01

    Full Text Available Typical adsorbent applied in solar-powered adsorption refrigeration cycle is activated carbon. It is known that activated alumina shows a higher adsorption capacity when it is tested in the laboratory using a constant radiation heat flux. In this study, solar-powered adsorption refrigeration cycle with generator filled by different adsorbents has been tested by exposing to solar radiation in Medan city of Indonesia. The generator is heated using a flat-plate type solar collector with a dimension of 0.5 m×0.5 m. Four cases experiments of solar-powered adsorption cycle were carried out, they are with generator filled by 100% activated alumina (named as 100AA, by a mixed of 75% activated alumina and 25% activated carbon (75AA, by a mixed of 25% activated alumina and 75% activated carbon (25AA, and filled by 100% activated carbon. Each case was tested for three days. The temperature and pressure history and the performance have been presented and analyzed. The results show that the average COP of 100AA, 75AA, 25AA, and 100AC is 0.054, 0.056, 0.06, and 0.074, respectively. The main conclusion can be drawn is that for Indonesian condition and flat-plate type solar collector the pair of activated carbon and methanol is the better than activated alumina.

  14. Solar Indices - Solar Flares

    Data.gov (United States)

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

  15. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

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

  16. Solar Indices - Solar Corona

    Data.gov (United States)

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

  17. Solar Indices - Solar Irradiance

    Data.gov (United States)

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

  18. Influence of solar activity on the state of the wheat market in medieval England

    Science.gov (United States)

    Pustil'Nik, Lev A.; Din, Gregory Yom

    2004-09-01

    The database of professor Rogers (1887), which includes wheat prices in England in the Middle Ages, was used to search for a possible influence of solar activity on the wheat market. Our approach was based on the following: (1) Existence of the correlation between cosmic ray flux entering the terrestrial atmosphere and cloudiness of the atmosphere. (2) Cosmic ray intensity in the solar system changes with solar activity, (3) Wheat production depends on weather conditions as a nonlinear function with threshold transitions. (4) A wheat market with a limited supply (as it was in medieval England) has a highly nonlinear sensitivity to variations in wheat production with boundary states, where small changes in wheat supply could lead to bursts of prices or to prices falling. We present a conceptual model of possible modes for sensitivity of wheat prices to weather conditions, caused by solar cycle variations, and compare expected price fluctuations with price variations recorded in medieval England. We compared statistical properties of the intervals between wheat price bursts during the years 1249-1703 with statistical properties of the intervals between the minima of solar cycles during the years 1700-2000. We show that statistical properties of these two samples are similar, both for characteristics of the distributions and for histograms of the distributions. We analyze a direct link between wheat prices and solar activity in the 17th century, for which wheat prices and solar activity data (derived from 10Be isotope) are available. We show that for all 10 time moments of the solar activity minima the observed prices were higher than prices for the corresponding time moments of maximal solar activity (100% sign correlation, on a significance level < 0.2%). We consider these results a direct evidence of the causal connection between wheat prices bursts and solar activity.

  19. Optimization of a PV/T (photovoltaic/thermal) active solar still

    International Nuclear Information System (INIS)

    Saeedi, F.; Sarhaddi, F.; Behzadmehr, A.

    2015-01-01

    In this paper, the optimization of a PV/T (photovoltaic/thermal) active solar still is carried out. Analytical expressions for glass cover temperature, basin temperature, brackish water temperature and fresh water productivity are obtained by writing energy balance for different components of PV/T active solar still. The output electrical power of PV/T active solar still is calculated by four-parameter I–V (current–voltage) model. Objective function in present study is the energy efficiency of PV/T active solar still. A computer simulation program has been developed in order to obtain thermal and electrical parameters, respectively. The simulation results of the present study are in fair agreement with the experimental data of previous literatures. Finally, the optimization of PV/T active solar still has been carried out and the optimized value of mass flow rate, number of PV/T collector and the objective function have been obtained. Furthermore, the effect of various operating parameters on energy efficiency have been investigated. - Highlights: • The comprehensive optimization of a PV/T active solar still is carried out. • Present study is based on numerical simulation. • A modified energy efficiency for PV/T active solar still is obtained. • The effect of design and operating parameters is investigated on energy efficiency

  20. Energy from solar balloons

    Energy Technology Data Exchange (ETDEWEB)

    Grena, Roberto [C. R. Casaccia, via Anguillarese 301, 00123 Roma (Italy)

    2010-04-15

    Solar balloons are hot air balloons in which the air is heated directly by the sun, by means of a black absorber. The lift force of a tethered solar balloon can be used to produce energy by activating a generator during the ascending motion of the balloon. The hot air is then discharged when the balloon reaches a predefined maximum height. A preliminary study is presented, along with an efficiency estimation and some considerations on possible realistic configurations. (author)

  1. VizieR Online Data Catalog: Solar activity reconstructed for 3 millennia (Usoskin+, 2014)

    Science.gov (United States)

    Usoskin, I. G.; Hulot, G.; Gallet, Y.; Roth, R.; Licht, A.; Joos, F.; Kovaltsov, G. A.; Thebault, E.; Khokhlov, A.

    2014-02-01

    Indices of solar activity reconstructed from 14C using the m used in the paper. Two indices are provided - the sunspot number and the cosmic ray modulation potential, both with the 95% confidence intervals. The data sets are provided with decadal resolution, thus the individual solar cycles are not resolved. (2 data files).

  2. Multi-parametric Effect of Solar Activity on Cosmic Rays V. K. Mishra ...

    Indian Academy of Sciences (India)

    Key words. Sun—solar parameters—cosmic ray modulation—running ... Neutron monitors are most sensitive to cosmic rays in the energy range. 0.5–20 GeV ... been considered as a primary indicator to define the level of solar activity, which.

  3. Energy Storage and Release through the Solar Activity Cycle Models Meet Radio Observations

    CERN Document Server

    Nindos, Alexander

    2012-01-01

    For nearly sixty years, radio observations have provided a unique insight into the physics of the active and quiescent solar atmosphere. Thanks to the variety of emission mechanisms and to the large altitude range available to observations, fundamental plasma parameters have been measured from the low chromosphere to the upper corona and interplanetary medium. This book presents current research in solar radio astronomy and shows how well it fits in the exceptional scientific context brought by the current space solar observatories. It essentially contains contributed research and review papers presented during the 2010 Community of European Solar Radio Astronomers (CESRA) meeting, which took place in Belgium in June 2010. This book is aimed at graduate students and researchers working in solar physics and space science. Previously published in Solar Physics journal, Vol. 273/2, 2011.

  4. Parametric studies of an active solar water heating system with ...

    Indian Academy of Sciences (India)

    overall photovoltaic thermal efficiency will increase and also will save valuable space. ... sumption of RM95 per month for a medium cost house (Faridah 2003). ..... Hence, the use of solar water heater shall improve public awareness in.

  5. Evolutionary charts of solar activity (calcium plages) as functions of heliographic longitude and time

    International Nuclear Information System (INIS)

    Hedeman, E.R.; Dodson, H.W.; Roelof, E.C.

    1981-08-01

    The richness and diversity of data relating to solar activity present a challenge from the point of view of organization and evaluation. For phenomena such as plages and centers of activity that tend to last for more than one solar rotation, a sequence of evolutionary charts based on heliographic longitude for successive solar rotations are discussed. Such a diagrammatic representation of calcium plages as a function of longitude and time, coupled with considerations of heliographic latitude, permits relatively easy and confident recognition of successively returning centers of activity

  6. Different parameter and technique affecting the rate of evaporation on active solar still -a review

    Science.gov (United States)

    A, Muthu Manokar; D, Prince Winston; A. E, Kabeel; Sathyamurthy, Ravishankar; T, Arunkumar

    2018-03-01

    Water is one of the essential sources for the endurance of human on the earth. As earth having only a small amount of water resources for consumption purpose people in rural and urban areas are getting affected by consuming dirty water that leads to water-borne diseases. Even though ground water is available in small quantity, it has to be treated properly before its use for internal consumption. Brackish water contains dissolve and undissolved contents, and hence it is not suitable for the household purpose. Nowadays, distillation process is done by using passive and active solar stills. The major problem in using passive solar still is meeting higher demand for fresh water. The fresh water production from passive solar still is critically low to meet the demand. To improve the productivity of conventional solar still, input feed water is preheated by integrating the solar still to different collector panels. In this review article, the different parameters that affect the rate of evaporation in an active solar still and the different methods incorporated has been presented. In addition to active distillation system, forced convection technique can be incorporated to increase the yield of fresh water by decreasing the temperature of cover. Furthermore, it is identified that the yield of fresh water from the active desalination system can be improved by sensible and latent heat energy storage. This review will motivate the researchers to decide appropriate active solar still technology for promoting development.

  7. Record of the Solar Activity and of Other Geophysical Phenomenons in Tree Ring

    Science.gov (United States)

    Rigozo, Nivaor Rodolfo

    1999-01-01

    Tree ring studies are usually used to determine or verify climatic factors which prevail in a given place or region and may cause tree ring width variations. Few studies are dedicated to the geophysical phenomena which may underlie these tree ring width variations. In order to look for periodicities which may be associated to the solar activity and/or to other geophysical phenomena which may influence tree ring growth, a new interactive image analysis method to measure tree ring width was developed and is presented here. This method makes use of a computer and a high resolution flatbed scanner; a program was also developed in Interactive Data Language (IDL 5.0) to study ring digitized images and transform them into time series. The main advantage of this method is the tree ring image interactive analysis without needing complex and high cost instrumentation. Thirty-nine samples were collected: 12 from Concordia - S. C., 9 from Canela - R. S., 14 from Sao Francisco de Paula - R. S., one from Nova Petropolis - R. S., 2 from Sao Martinho da Serra - R. S. e one from Chile. Fit functions are applied to ring width time series to obtain the best long time range trend (growth rate of every tree) curves and are eliminated through a standardization process that gives the tree ring index time series from which is performed spectral analysis by maximum entropy method and iterative regression. The results obtained show periodicities close to 11 yr, 22 yr Hale solar cycles and 5.5 yr for all sampling locations 52 yr and Gleissberg cycles for Concordia - S. C. and Chile samples. El Nino events were also observed with periods around 4 e 7 yr.

  8. Effects of total solar eclipse on the behavioural and metabolic activities of tropical intertidal animals

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Ansari, Z.A.; Verlecar, X.N.; Harkantra, S.N.

    To study the effects of total solar eclipse of 16th Feb. 1980, on the behaviour and metabolic activities of intertidal invertebrates - nematodes, gastropods and bivalves - having different habitat preference a set of relevant observations, covering...

  9. Enerplan - union of solar energy professionals, activity report second half of 2012

    International Nuclear Information System (INIS)

    2013-01-01

    Enerplan is the French union of solar energy professionals. Created in 1983, its social purpose is the study and defense of the rights and of the material and moral interests of its members. Enerplan structures its action through two poles representing members' activities: 'solar energy and building' where topics about heat and electricity generation in relation with buildings are treated, and 'photovoltaic energy' where topics specific to big solar power plants are considered. Thanks to the collaborative participation of its members, both poles allow Enerplan union to be source of proposals to develop solar energy in France. As an active interface between professionals and institutions, Enerplan includes in its membership: industrialists, plant makers, engineering consultants, installers, associations, energy suppliers etc, from small-medium size companies to big groups. This document presents Enerplan's activities during the second half of 2012 (public relations, meetings and conferences, promotional activities, projects..)

  10. Enerplan - union of solar energy professionals, activity report first half of 2013

    International Nuclear Information System (INIS)

    2013-01-01

    Enerplan is the French union of solar energy professionals. Created in 1983, its social purpose is the study and defense of the rights and of the material and moral interests of its members. Enerplan structures its action through two poles representing members' activities: 'solar energy and building' where topics about heat and electricity generation in relation with buildings are treated, and 'photovoltaic energy' where topics specific to big solar power plants are considered. Thanks to the collaborative participation of its members, both poles allow Enerplan union to be source of proposals to develop solar energy in France. As an active interface between professionals and institutions, Enerplan includes in its membership: industrialists, plant makers, engineering consultants, installers, associations, energy suppliers etc, from small-medium size companies to big groups. This document presents Enerplan's activities during the first half of 2013 (public relations, meetings and conferences, promotional activities, projects..)

  11. Enerplan, activity report 2009. Acting for solar energy promotion and development

    International Nuclear Information System (INIS)

    2010-01-01

    Enerplan is the French union of solar energy professionals. Created in 1983, its social purpose is the study and defense of the rights and of the material and moral interests of its members. Enerplan structures its action through two poles representing members' activities: 'solar energy and building' where topics about heat and electricity generation in relation with buildings are treated, and 'photovoltaic energy' where topics specific to big solar power plants are considered. Thanks to the collaborative participation of its members, both poles allow Enerplan union to be source of proposals to develop solar energy in France. As an active interface between professionals and institutions, Enerplan includes in its membership: industrialists, plant makers, engineering consultants, installers, associations, energy suppliers etc, from small-medium size companies to big groups. This document presents Enerplan's activities in 2009 (public relations, lobbying, meetings and conferences, promotional activities, collaborations, projects..)

  12. Responses of Solar Irradiance and the Ionosphere to an Intense Activity Region

    Science.gov (United States)

    Chen, Yiding; Liu, Libo; Le, Huijun; Wan, Weixing

    2018-03-01

    Solar rotation (SR) variation dominates solar extremely ultraviolet (EUV) changes on the timescale of days. The F10.7 index is usually used as an indicator for solar EUV. The SR variation of F10.7 significantly enhanced during the 2008th-2009th Carrington rotations (CRs) owing to an intense active region; F10.7 increased about 180 units during that SR period. That was the most prominent SR variation of F10.7 during solar cycle 23. In this paper, global electron content (GEC) is used to investigate ionospheric response to that strong variation of solar irradiance indicated by F10.7. The variation of GEC with F10.7 was anomalous (GEC-F10.7 slope significantly decreased) during the 2008th-2009th CRs; however, GEC versus EUV variation during that period was consistent with that during adjacent time intervals when using Solar Heliospheric Observatory/Solar EUV Monitor 26-34 nm EUV measurements. The reason is that F10.7 response to that intense active region was much stronger than EUV response; thus, the EUV-F10.7 slope decreased. We confirmed decreased EUV-F10.7 slope during the 2008th-2009th CRs for different wavelengths within 27-120 nm using Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Solar EUV Experiment high spectral resolution EUV measurements. And on the basis of Solar Heliospheric Observatory/Solar EUV Monitor EUV measurements during solar cycle 23, we further presented that EUV-F10.7 slope statistically tends to decrease when the SR variation of F10.7 significantly enhances. Moreover, we found that ionospheric time lag effect to EUV is exaggerated when using F10.7, owing to the time lag effect of EUV to F10.7.

  13. 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.

  14. Rate of production of cosmogenic isotopes in the past and solar activity

    International Nuclear Information System (INIS)

    Kocharov, G.E.; Dergachev, V.A.; Gordeichik, N.I.; Ioffe, A.F.

    1975-01-01

    The available experimental data on abundances of 14 C, 10 Be and 26 Al in materials with known ages are analyzed with the aim of determining of solar activity in the past. Based on the authors results on the abundances of 14 C in the tree rings it is shown that concentration of radiocarbon in atmosphere is changed with the period of approximately 60 years, amplitude approcimately 1% and phase shift relatively to solar activity of approximately 10 years. (orig./WBU) [de

  15. Coupling of the solar wind to measures of magnetic activity

    International Nuclear Information System (INIS)

    McPherron, R.L.; Fay, R.A.; Garrity, C.R.; Bargatze, L.F.; Baker, D.N.; Clauer, C.R.; Searls, C.

    1984-01-01

    The technique of linear prediction filtering has been used to generate empirical response functions relating the solar wind electric field to the most frequently used magnetic indices, AL, AU, Dst and ASYM. Two datasets, one from 1967-1968 and one from 1973-1974, provided the information needed to calculate the empirical response functions. These functions have been convolved with solar wind observations obtained during the IMS to predict the indices. These predictions are compared with the observed indices during two, three-day intervals studied extensively by participants in the CDAW-6 workshop. Differences between the observed and predicted indices are discussed in terms of the linear assumption and in terms of physical processes other than direct solar wind-magnetosphere interaction

  16. ON MAGNETIC ACTIVITY BAND OVERLAP, INTERACTION, AND THE FORMATION OF COMPLEX SOLAR ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Scott W. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); Leamon, Robert J., E-mail: mscott@hao.ucar.edu [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2014-11-20

    Recent work has revealed a phenomenological picture of the how the ∼11 yr sunspot cycle of the Sun arises. The production and destruction of sunspots is a consequence of the latitudinal-temporal overlap and interaction of the toroidal magnetic flux systems that belong to the 22 yr magnetic activity cycle and are rooted deep in the Sun's convective interior. We present a conceptually simple extension of this work, presenting a hypothesis on how complex active regions can form as a direct consequence of the intra- and extra-hemispheric interaction taking place in the solar interior. Furthermore, during specific portions of the sunspot cycle, we anticipate that those complex active regions may be particularly susceptible to profoundly catastrophic breakdown, producing flares and coronal mass ejections of the most severe magnitude.

  17. Measurement of solar neutrinos flux in Russian-American gallium experiment SAGE for half 22-years cycle of solar activity

    International Nuclear Information System (INIS)

    Abdurashitov, D.N.; Veretenkin, E.P.; Vermul, V.M.

    2002-01-01

    The results of measuring the solar neutrino capture on the metallic gallium in the Russian-American experiment SAGE for the period slightly exceeding the half of the 22-year cycle of solar activity, are presented. The results of new measurements since April 1998 are quoted and the analysis of all the measurements, performed by years, months and two-year periods, beginning since 1990 are also presented. Simple analysis of the SAGE results together with the results of other solar neutrino experiments leads to estimating the value of the flux of the pp-neutrinos, reaching the Earth without change in their around, equal to (4.6 ± 1.2) x 10 10 neutrino/(cm 2 s). The value of the flux of the pp-neutrinos, originating in the Sun thermonuclear reactions, is equal to (7.6 ± 2.0) x 10 10 neutrino/(cm 2 s), which agrees well with the standard solar model (5.95 ± 0.6) x 10 10 neutrino/(cm 2 s) [ru

  18. On a relation of geomagnetic activity, solar wind velocity and irregularity of daily rotation of the Earth

    International Nuclear Information System (INIS)

    Kalinin, Yu.D.; Kiselev, V.M.

    1980-01-01

    A possibility of the presence of statistic relation between the changes of the Earth rotation regime and the mean velocity of solar wind is discussed. The ratio between the solar wind velocity observed and planetary index of geomagnetic activity am is used to determine the annual average values of solar wind velocity beyond the twentieth cycle of solar activity. The restored changes of solar wind velocity are compared with solar conditioned variations of the Earth day duration and it is shown that the correspondence takes place only at frequencies lower the frequency of 11-year cycle [ru

  19. Maximum power point tracking

    International Nuclear Information System (INIS)

    Enslin, J.H.R.

    1990-01-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

  20. Signatures of Slow Solar Wind Streams from Active Regions in the Inner Corona

    Science.gov (United States)

    Slemzin, V.; Harra, L.; Urnov, A.; Kuzin, S.; Goryaev, F.; Berghmans, D.

    2013-08-01

    The identification of solar-wind sources is an important question in solar physics. The existing solar-wind models ( e.g., the Wang-Sheeley-Arge model) provide the approximate locations of the solar wind sources based on magnetic field extrapolations. It has been suggested recently that plasma outflows observed at the edges of active regions may be a source of the slow solar wind. To explore this we analyze an isolated active region (AR) adjacent to small coronal hole (CH) in July/August 2009. On 1 August, Hinode/EUV Imaging Spectrometer observations showed two compact outflow regions in the corona. Coronal rays were observed above the active-region coronal hole (ARCH) region on the eastern limb on 31 July by STEREO-A/EUVI and at the western limb on 7 August by CORONAS- Photon/TESIS telescopes. In both cases the coronal rays were co-aligned with open magnetic-field lines given by the potential field source surface model, which expanded into the streamer. The solar-wind parameters measured by STEREO-B, ACE, Wind, and STEREO-A confirmed the identification of the ARCH as a source region of the slow solar wind. The results of the study support the suggestion that coronal rays can represent signatures of outflows from ARs propagating in the inner corona along open field lines into the heliosphere.

  1. Major activities of the association ''Arbeitsgemeinschaft Solar NRW''. Decentralized energy systems development, trial and qualification

    International Nuclear Information System (INIS)

    Meliss, M.

    1996-01-01

    In North-Rhine Westphalia, the Ministry for Science and Research and the Ministry for Economic Affairs, Medium-Sized Companies and Technology (MWF) in 1991 decided to jointly establish a research and technology association called AG Solar NRW, intended to function as a central body for promotion and coordination of existing but dispersed projects and activities in North-Rhine Westphalia for research into and development of solar technology and energy systems, and for promotion of demonstration projects and training programmes supporting enhanced use of solar energy. The total budget made available for activities of the AG Solar in phase 1 (1991 - 1995) was approx. DM 60 million. The article in hand summarizes the main activities and results achieved in this first phase which was committed to decentralized energy systems, performance testing and qualification. (orig.) [de

  2. Radiation From Solar Activity | Radiation Protection | US EPA

    Science.gov (United States)

    2017-08-07

    Solar flares, coronal mass ejections (CMEs) and geomagnetic storms from the sun can send extreme bursts of ionizing radiation and magnetic energy toward Earth. Some of this energy is in the form ionizing radiation and some of the energy is magnetic energy.

  3. Polar coronal holes and solar cycles

    International Nuclear Information System (INIS)

    Simon, P.A.

    1979-01-01

    The relationship between the geomagnetic activity of the three years preceding a sunspot minimum and the peak of the next sunspot maximum confirms the polar origin of the solar wind during one part of the solar cycle. Pointing out that the polar holes have a very small size or disappear at the time of the polar field reversal, a low latitude origin of the solar-wind at sunspot maximum is suggested and the cycle variation of solar wind and geomagnetic activity is described. In addition a close relationship is noted between the maximum level of the geomagnetic activity reached a few years before a solar minimum and its level at the next sunspot maximum. Studying separately the effects of both the low latitude holes and the solar activity, the possibility of predicting both the level of geomagnetic activity and the sunspot number at the next sunspot maximum is pointed out. As a conclusion the different categories of phenomena contributing to a solar cycle are specified. (Auth.)

  4. Electric-current Neutralization, Magnetic Shear, and Eruptive Activity in Solar Active Regions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Sun, Xudong [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Török, Tibor; Titov, Viacheslav S. [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Leake, James E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2017-09-01

    The physical conditions that determine whether or not solar active regions (ARs) produce strong flares and coronal mass ejections (CMEs) are not yet well understood. Here, we investigate the association between electric-current neutralization, magnetic shear along polarity inversion lines (PILs), and eruptive activity in four ARs: two emerging and two well-developed ones. We find that the CME-producing ARs are characterized by a strongly non-neutralized total current, while the total current in the ARs that did not produce CMEs is almost perfectly neutralized. The difference in the PIL shear between these two groups is much less pronounced, which suggests that the degree of current neutralization may serve as a better proxy for assessing the ability of ARs to produce CMEs.

  5. Solar and interplanetary activities of isolated and non-isolated coronal mass ejections

    Science.gov (United States)

    Bendict Lawrance, M.; Shanmugaraju, A.; Moon, Y.-J.; Umapathy, S.

    2017-07-01

    We report our results on comparison of two halo Coronal Mass Ejections (CME) associated with X-class flares of similar strength (X1.4) but quite different in CME speed and acceleration, similar geo-effectiveness but quite different in Solar Energetic Particle (SEP) intensity. CME1 (non-isolated) was associated with a double event in X-ray flare and it was preceded by another fast halo CME of speed = 2684 km/s (pre-CME) associated with X-ray flare class X5.4 by 1 h from the same location. Since this pre-CME was more eastern, interaction with CME1 and hitting the earth were not possible. This event (CME1) has not suffered the cannibalism since pre-CME has faster speed than post-CME. Pre-CME plays a very important role in increasing the intensity of SEP and Forbush Decrease (FD) by providing energetic seed particles. So, the seed population is the major difference between these two selected events. CME2 (isolated) was a single event. We would like to address on the kinds of physical conditions related to such CMEs and their associated activities. Their associated activities such as, type II bursts, SEP, geomagnetic storm and FD are compared. The following results are obtained from the analysis. (1) The CME leading edge height at the start of metric/DH type II bursts are 2 R⊙/ 4 R⊙ for CME1, but 2 R⊙/ 2.75 R⊙ for CME2. (2) Peak intensity of SEP event associated with the two CMEs are quite different: 6530 pfu for CME1, but 96 pfu for CME2. (3) The Forbush decrease occurred with a minimum decrease of 9.98% in magnitude for CME1, but 6.90% for CME2. (4) These two events produced similar intense geomagnetic storms of intensity of Dst index -130 nT. (5) The maximum southward magnetic fields corresponding to Interplanetary CME (ICME) of these two events are nearly the same, but there is difference in Sheath Bz maximum (-14.2, -6.9 nT). (6) The time-line chart of the associated activities of two CMEs show some difference in the time delay between the onsets of

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

    Science.gov (United States)

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

    2017-01-01

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

  7. Solar activity and terrestrial climate: an analysis of some purported correlations

    DEFF Research Database (Denmark)

    Laut, Peter

    2003-01-01

    claimed to support solar hypotheses. My analyses show that the apparent strong correlations displayed on these graphs have been obtained by an incorrect handling of the physical data. Since the graphs are still widely referred to in the literature and their misleading character has not yet been generally......The last decade has seen a revival of various hypotheses claiming a strong correlation between solar activity and a number of terrestrial climate parameters: Links between cosmic rays and cloud cover, first total cloud cover and then only low clouds, and between solar cycle lengths and Northern...... the existence of important links between solar activity and terrestrial climate. Such links have over the years been demonstrated by many authors. The sole objective of the present analysis is to draw attention to the fact that some of the widely publicized, apparent correlations do not properly reflect...

  8. Response of the mesopause airglow to solar activity inferred from measurements at Zvenigorod, Russia

    Directory of Open Access Journals (Sweden)

    N. Pertsev

    2008-05-01

    Full Text Available Ground-based spectrographical observations of infrared emissions of the mesopause region have been made at Zvenigorod Observatory (56 N, 37 E, located near Moscow, Russia, for 670 nights of 2000–2006. The characteristics of the hydroxyl and molecular oxygen (865 nm airglow, heights of which correspond to 87 and 94 km, are analyzed for finding their response to solar activity. The measured data exhibit a response to the F10.7 solar radio flux change, which is 30%–40%/100 sfu in intensities of the emissions and about 4.5 K/100 sfu in hydroxyl temperature. Seasonal variations of the airglow response to solar activity are observed. In winter it is more significant than in summer. Mechanisms that may provide an explanation of the solar influence on intensities of the emissions and temperature are considered. Radiative processes not involving atmospheric dynamics appear insufficient to explain the observed effect.

  9. Response of the mesopause airglow to solar activity inferred from measurements at Zvenigorod, Russia

    Directory of Open Access Journals (Sweden)

    N. Pertsev

    2008-05-01

    Full Text Available Ground-based spectrographical observations of infrared emissions of the mesopause region have been made at Zvenigorod Observatory (56 N, 37 E, located near Moscow, Russia, for 670 nights of 2000–2006. The characteristics of the hydroxyl and molecular oxygen (865 nm airglow, heights of which correspond to 87 and 94 km, are analyzed for finding their response to solar activity. The measured data exhibit a response to the F10.7 solar radio flux change, which is 30%–40%/100 sfu in intensities of the emissions and about 4.5 K/100 sfu in hydroxyl temperature. Seasonal variations of the airglow response to solar activity are observed. In winter it is more significant than in summer. Mechanisms that may provide an explanation of the solar influence on intensities of the emissions and temperature are considered. Radiative processes not involving atmospheric dynamics appear insufficient to explain the observed effect.

  10. Active solar heating system performance and data review

    Energy Technology Data Exchange (ETDEWEB)

    Bates, J.; Bertarelli, L.; Schmidt, G.

    1999-07-01

    This report summarises the results of a study investigating the performance and costs of solar heating systems in Europe, and their relevance to systems in the UK. Details are given of the identification and review of the available data, the collection of information on UK and overseas systems, and the assessment and analysis of the data. Appendices give a lists of the monitored parameters, European contacts, data sources, the questionnaire for gathering information, and a printout of the data files. (uk)

  11. Gaharu Leaf Extract Water Reduce MDA and 8-OHdG Levels and Increase Activities SOD and Catalase in Wistar Rats Provided Maximum Physical Activity

    Directory of Open Access Journals (Sweden)

    I Made Oka Adi Parwata

    2016-09-01

    Full Text Available Background: Oxidative stress occurs due to an imbalance of the number of free radicals by the number of endogenous antioxidant produced by the body i.e. Superoxide Dismutase (SOD, Gluthathione Peroxidase (GPx, and Catalase. The imbalance between the number of free radicals and antioxidants can be overcome with the endogenous antioxidant intake that exogenous oxidative stress can be reduced. One of exogenous antioxidants is natural Gaharu leaf water extract. Objective: This research focus on the effect of Gaharu leaf water extract in reducing MDA and 8-OHdG and increase the activity of SOD and Catalase. Methods: This study was an experimental with post only controls group design. Experiment was divided  into 5 groups of wistar rats, each consisting of 5 animals, i.e. negative control group without extract [K (-], treatment 1 treated 50 mg/kg BW/day of the extract (T1, treatment 2 treated 100 mg/kg BW/day of the extract (T2, treatment 3 treated 200 mg/ kg BW/day of the extract (T3, and positive control group [K (+] treated with vitamin Cat a dose 50 mg/kg BW/day. All groups treated for 10 weeks. Every day, before treatment, each group was given a maximum swimming activity for 1.5 hours for 10 weeks. ELISA was used to measure MDA, 8-OHdG, SOD, and Catalase activities. Result: The research results showed that treatment of extract of  leaves of Gaharu with an higher dose from 50 mg/kg BW up to 200 mg/ kg BW significantly decline (p <0.05 levels of MDA with the average ranging from 6.37±0.23, 5,56±0.27 and 4.32±0.27, 8-OHdG with a mean of 1.64±0.11, 1.26±0.46, and 1.09±0.17. On the other hand the treatment also increase SOD activity with less ranging from 12.15±1.04, 15.70±2.02, and 18.84±1.51, and Catalase ranging from 6,68±0.63, 8.20±1.14 and 9.29±0,79 in the blood of Wistar rats were given a maximum activity compared to the negative control group. This is probably higher phenol compounds (bioflavonoids quantity content of the extract

  12. Solar activity indices as a proxy for the variation of ionospheric Total Electron Content (TEC) over Bahir Dar, Ethiopia during the year 2010-2014

    Science.gov (United States)

    Kassa, Tsegaye; Tilahun, Samson; Damtie, Baylie

    2017-09-01

    This paper was aimed at investigating the solar variations of vTEC as a function of solar activity parameters, EUV and F10.7 radio flux. The daily values of ionospheric vertical Total Electron Content (vTEC) were observed using a dual frequency GPS receiver deployed at Bahir Dar (11.6°N and 37.36°E), Ethiopia. Measurements were taken during the period of 2010-2014 for successive five years and analysis was done on only quiet day observations. A quadratic fit was used as a model to describe the daily variation of vTEC in relation to solar parameters. Linear and non-linear coefficients of the vTEC variations were calculated in order to capture the trend of the variation. The variation of vTEC have showed good agreement with the trend of solar parameters in almost all of the days we consider during the period of our observations. We have explicitly observed days with insignificant TECU deviation (eg. modeling with respect to EUV, DOY = 49 in 2010 and modeling with respect to F10.7, DOY = 125 in 2012 and the like) and days with maximum deviation (about 50 TECU). A maximum deviation were observed, on average, during months of equinox whereas minimum during solstice months. This implies that there is a need to consider more parameters, including EUV and F10.7, that can affect the variation of vTEC during equinox seasons. Relatively, small deviations was observed in modeling vTEC as a function of EUV compared to that of the variation due to F10.7 cm flux. This may also tell us that EUV can be more suitable in modeling the solar variation of vTEC especially for longterm trends. Even though, the linear trend of solar variations of vTEC was frequently observed, significant saturation and amplification trends of the solar variations of vTEC were also observed to some extent across the months of the years we have analyzed. This mixed trend of the solar variation of vTEC implies the need for thorough investigation on the effect of solar parameters on TEC. However, based on

  13. North-south asymmetry of solar activity as a superposition of two realizations - the sign and absolute value

    Science.gov (United States)

    Badalyan, O. G.; Obridko, V. N.

    2017-07-01

    Context. Since the occurrence of north-south asymmetry (NSA) of alternating sign may be determined by different mechanisms, the frequency and amplitude characteristics of this phenomenon should be considered separately. Aims: We propose a new approach to the description of the NSA of solar activity. Methods: The asymmetry defined as A = (N-S)/(N + S) (where N and S are, respectively, the indices of activity of the northern and southern hemispheres) is treated as a superposition of two functions: the sign of asymmetry (signature) and its absolute value (modulus). This approach is applied to the analysis of the NSA of sunspot group areas for the period 1874-2013. Results: We show that the sign of asymmetry provides information on the behavior of the asymmetry. In particular, it displays quasi-periodic variation with a period of 12 yr and quasi-biennial oscillations as the asymmetry itself. The statistics of the so-called monochrome intervals (long periods of positive or negative asymmetry) are considered and it is shown that the distribution of these intervals is described by the random distribution law. This means that the dynamo mechanisms governing the cyclic variation of solar activity must involve random processes. At the same time, the asymmetry modulus has completely different statistical properties and is probably associated with processes that determine the amplitude of the cycle. One can reliably isolate an 11-yr cycle in the behavior of the asymmetry absolute value shifted by half a period with respect to the Wolf numbers. It is shown that the asymmetry modulus has a significant prognostic value: the higher the maximum of the asymmetry modulus, the lower the following Wolf number maximum. Conclusions: A fundamental nature of this concept of NSA is discussed in the context of the general methodology of cognizing the world. It is supposed that the proposed description of the NSA will help clarify the nature of this phenomenon.

  14. NmF2 Morphology during four-classes of solar and magnetic activity conditions at an African station around the EIA trough and comparison with IRI-2016 Map

    Science.gov (United States)

    Adebesin, B.; Rabiu, B.; Obrou, O. K.

    2017-12-01

    Better understanding of the electrodynamics between parameters used in describing the ionospheric layer and their solar and geomagnetic influences goes a long way in furthering the expansion of space weather knowledge. Telecommunication and scientific radar launch activities can however be interrupted either on a larger/smaller scales by geomagnetic activities which is susceptible to changes in solar activity and effects. Consequently, the ionospheric NmF2 electrodynamics was investigated for a station near the magnetic dip in the African sector (Korhogo, Geomagnetic: -1.26°N, 67.38°E). Data covering years 1996 and 2000 were investigated for four categories of magnetic and solar activities viz (i) F10.7 7 nT (low solar disturbed, LSD); (iii) F10.7 > 150 sfu, ap ≤ 7 nT (high solar quiet, HSQ); and (iv) F10.7 > 150 sfu, ap > 7 nT (high solar disturbed, HSD). NmF2 revealed a pre-noon peak higher than the post-noon peak during high solar activity irrespective of magnetic activity condition and overturned during low solar activity. Higher NmF2 peak amplitude however characterise disturbed magnetic activity than quiet magnetic condition for any solar activity. The maximum pre-/post-noon peaks appeared in equinox season. June solstice noon-time bite out lagged other seasons by 1-2 h. Daytime variability increases with increasing magnetic activity. Equinox/June solstice recorded the highest pre-sunrise/post-sunset peak variability magnitudes with the lowest emerging in June solstice/equinox for all solar and magnetic conditions. The nighttime annual variability amplitude is higher during disturbed than quiet condition regardless of solar activity period; while the range is similar for daytime observations. The noon-time trough characteristics is not significant in the IRI NmF2 pattern during high solar activity but evident during low solar conditions. IRI-2016 map performed best during disturbed activity conditions especially for F10.7 7 nT condition.

  15. Activity associated with coronal mass ejections at solar minimum - SMM observations from 1984-1986

    Science.gov (United States)

    St. Cyr, O. C.; Webb, D. F.

    1991-01-01

    Seventy-three coronal mass ejections (CMEs) observed by the coronagraph aboard SMM between 1984 and 1986 were examined in order to determine the distribution of various forms of solar activity that were spatially and temporally associated with mass ejections during solar minimum phase. For each coronal mass ejection a speed was measured, and the departure time of the transient from the lower corona estimated. Other forms of solar activity that appeared within 45 deg longitude and 30 deg latitude of the mass ejection and within +/-90 min of its extrapolated departure time were explored. The statistical results of the analysis of these 73 CMEs are presented, and it is found that slightly less than half of them were infrequently associated with other forms of solar activity. It is suggested that the distribution of the various forms of activity related to CMEs does not change at different phases of the solar cycle. For those CMEs with associations, it is found that eruptive prominences and soft X-rays were the most likely forms of activity to accompany the appearance of mass ejections.

  16. Solar spectral irradiance variability of some chromospheric emission lines through the solar activity cycles 21-23

    Directory of Open Access Journals (Sweden)

    Göker Ü.D.

    2017-01-01

    Full Text Available A study of variations of solar spectral irradiance (SSI in the wave-length ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV spectral lines and international sunspot number (ISSN from interactive data centers such as SME (NSSDC, UARS (GDAAC, SORCE (LISIRD and SIDC, respectively. We reduced these data by using the MATLsoftware package. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm spectral lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar activity cycles (SACs 23 and 24. We also compared our results with the variations of solar activity indices obtained by the ground-based telescopes. Therefore, we found that plage regions decrease while facular areas are increasing in SAC 23. However, the decrease in plage regions is seen in small sunspot groups (SGs, contrary to this, these regions in large SGs are comparable to previous SACs or even larger as is also seen in facular areas. Nevertheless, negative correlations between ISSN and SSI data indicate that these variations are in close connection with the classes of sunspots/SGs, faculae and plage regions. Finally, we applied the time series analysis of spectral lines corresponding to the wavelengths 121.5 nm-300.5 nm and made comparisons with the ISSN data. We found an unexpected increase in the 298.5 nm line for the Fe II ion. The variability of Fe II ion 298.5 nm line is in close connection with the facular areas and plage regions, and the sizes of these solar surface indices play an important role for the SSI variability, as well. So, we compared the connection between the sizes of faculae and plage regions, sunspots/SGs, chemical elements and SSI variability. Our future work will be the theoretical study of this connection and developing of a corresponding model.

  17. Latitude dependence of long-term geomagnetic activity and its solar wind drivers

    Energy Technology Data Exchange (ETDEWEB)

    Myllys, M. [Helsinki Univ. (Finland). Dept. of Physics; Partamies, N. [Finnish Meteorological Institute, Helsinki (Finland); University Centre in Svalbard, Longyearbyen (Norway). Dept. of Arctic Geophysics; Juusola, L. [Finnish Meteorological Institute, Helsinki (Finland)

    2015-09-01

    To validate the usage of global indices in studies of geomagnetic activity, we have examined the latitude dependence of geomagnetic variations in Fennoscandia and Svalbard from 1994 to 2010. Daily standard deviation (SD) values of the horizontal magnetic field have been used as a measure of the ground magnetic disturbance level.We found that the timing of the geomagnetic minimum depends on the latitude region: corresponding to the minimum of sunspot cycle 22 (in 1996), the geomagnetic minimum occurred between the geomagnetic latitudes 57-61 in 1996 and at the latitudes 64-67 in 1997, which are the average auroral oval latitudes. During sunspot cycle 23, all latitude regions experienced the minimum in 2009, a year after the sunspot minimum. These timing differences are due to the latitude dependence of the 10 s daily SD on the different solar wind drivers. In the latitude region of 64-67 , the impact of the high-speed solar wind streams (HSSs) on the geomagnetic activity is the most pronounced compared to the other latitude groups, while in the latitude region of 57-61 , the importance of the coronal mass ejections (CMEs) dominates. The geomagnetic activity maxima during ascending solar cycle phases are typically caused by CME activity and occur especially in the oval and sub-auroral regions. The strongest geomagnetic activity occurs during the descending solar cycle phases due to a mixture of CME and HSS activity. Closer to the solar minimum, less severe geomagnetic activity is driven by HSSs and mainly visible in the poleward part of the auroral region. According to our study, however, the timing of the geomagnetic activity minima (and maxima) in different latitude bands is different, due to the relative importance of different solar wind drivers at different latitudes.

  18. Latitude dependence of long-term geomagnetic activity and its solar wind drivers

    International Nuclear Information System (INIS)

    Myllys, M.

    2015-01-01

    To validate the usage of global indices in studies of geomagnetic activity, we have examined the latitude dependence of geomagnetic variations in Fennoscandia and Svalbard from 1994 to 2010. Daily standard deviation (SD) values of the horizontal magnetic field have been used as a measure of the ground magnetic disturbance level.We found that the timing of the geomagnetic minimum depends on the latitude region: corresponding to the minimum of sunspot cycle 22 (in 1996), the geomagnetic minimum occurred between the geomagnetic latitudes 57-61 in 1996 and at the latitudes 64-67 in 1997, which are the average auroral oval latitudes. During sunspot cycle 23, all latitude regions experienced the minimum in 2009, a year after the sunspot minimum. These timing differences are due to the latitude dependence of the 10 s daily SD on the different solar wind drivers. In the latitude region of 64-67 , the impact of the high-speed solar wind streams (HSSs) on the geomagnetic activity is the most pronounced compared to the other latitude groups, while in the latitude region of 57-61 , the importance of the coronal mass ejections (CMEs) dominates. The geomagnetic activity maxima during ascending solar cycle phases are typically caused by CME activity and occur especially in the oval and sub-auroral regions. The strongest geomagnetic activity occurs during the descending solar cycle phases due to a mixture of CME and HSS activity. Closer to the solar minimum, less severe geomagnetic activity is driven by HSSs and mainly visible in the poleward part of the auroral region. According to our study, however, the timing of the geomagnetic activity minima (and maxima) in different latitude bands is different, due to the relative importance of different solar wind drivers at different latitudes.

  19. Simplified method of checking the observance of maximum permissible activity of waste forms to be placed in the Konrad shaft for final waste storage

    International Nuclear Information System (INIS)

    Berg, H.P.; Piefke, F.

    1986-10-01

    The requirements to be met by waste forms destined for final storage in the Konrad shaft among others define maximum permissible activity levels which have been determined from the various parts of the safety analyses. For waste forms with very low activity levels, it is suitable to compile all the very specific requirements in one checking list, and to perform the checking as simply as adequate. On the basis of the compilation of requirements defined for normal operation of the storage facility, hypothetical accidents, thermal loads affecting the host rock, and criticality safety, the maximum permissible activities are derived that are to be checked by the simplified control measures explained. The report explains the computer programs for the ANKONA code. (orig.) [de

  20. Solar activity variations of equatorial spread F occurrence and sustenance during different seasons over Indian longitudes: Empirical model and causative mechanisms

    Science.gov (United States)

    Madhav Haridas, M. K.; Manju, G.; Arunamani, T.

    2018-05-01

    A comprehensive analysis using nearly two decades of ionosonde data is carried out on the seasonal and solar cycle variations of Equatorial Spread F (ESF) irregularities over magnetic equatorial location Trivandrum (8.5°N, 77°E). The corresponding Rayleigh Taylor (RT) instability growth rates (γ) are also estimated. A seasonal pattern of ESF occurrence and the corresponding γ is established for low solar (LSA), medium solar (MSA) and high solar (HSA) activity periods. For LSA, it is seen that the γ maximizes during post sunset time with comparable magnitudes for autumnal equinox (AE), vernal equinox (VE) and winter solstice (WS), while for summer solstice (SS) it maximizes in the post-midnight period. Concurrent responses are seen in the ESF occurrence pattern. For MSA, γ maximizes during post-sunset for VE followed by WS and AE while SS maximises during post-midnight period. The ESF occurrence for MSA is highest for VE (80%), followed by AE (70%), WS (60%) and SS (50%). In case of HSA, maximum γ occurs for VE followed by AE, WS and SS. The concurrent ESF occurrence maximizes for VE and AE (90%), WS and SS at 70%. The solar cycle variation of γ is examined. γ shows a linear variation with F10.7 cm flux. Further, ESF percentage occurrence and duration show an exponential and linear variation respectively with γ. An empirical model on the solar activity dependence of ESF occurrence and sustenance time over Indian longitudes is arrived at using the database spanning two solar cycles for the first time.

  1. Solar Activity, Ultraviolet Radiation and Consequences in Birds in Mexico City, 2001- 2002

    Science.gov (United States)

    Valdes, M.; Velasco, V.

    2008-12-01

    Anomalous behavior in commercial and pet birds in Mexico City was reported during 2002 by veterinarians at the Universidad Nacional Autonoma de Mexico. This was attributed to variations in the surrounding luminosity. The solar components, direct, diffuse, global, ultraviolet band A and B, as well as some meteorological parameters, temperature, relative humidity, and precipitation, were then analyzed at the Solar Radiation Laboratory. Although the total annual radiance of the previously mentioned radiation components did not show important changes, ultraviolet Band-B solar radiation did vary significantly. During 2001 the total annual irradiance , 61.05 Hjcm² to 58.32 Hjcm², was 1.6 standard deviations lower than one year later, in 2002 and increased above the mean total annual irradiance, to 65.75 Hjcm², 2.04 standard deviations, giving a total of 3.73 standard deviations for 2001-2002. Since these differences did not show up clearly in the other solar radiation components, daily extra-atmosphere irradiance was analyzed and used to calculate the total annual extra-atmosphere irradiance, which showed a descent for 2001. Our conclusions imply that Ultraviolet Band-B solar radiation is representative of solar activity and has an important impact on commercial activity related with birds.

  2. Solar wind and geomagnetism: toward a standard classification of geomagnetic activity from 1868 to 2009

    Directory of Open Access Journals (Sweden)

    J. L. Zerbo

    2012-02-01

    Full Text Available We examined solar activity with a large series of geomagnetic data from 1868 to 2009. We have revisited the geomagnetic activity classification scheme of Legrand and Simon (1989 and improve their scheme by lowering the minimum Aa index value for shock and recurrent activity from 40 to 20 nT. This improved scheme allows us to clearly classify about 80% of the geomagnetic activity in this time period instead of only 60% for the previous Legrand and Simon classification.

  3. Hilbert-Huang transform analysis of long-term solar magnetic activity

    Science.gov (United States)

    Deng, Linhua

    2018-04-01

    Astronomical time series analysis is one of the hottest and most important problems, and becomes the suitable way to deal with the underlying dynamical behavior of the considered nonlinear systems. The quasi-periodic analysis of solar magnetic activity has been carried out by various authors during the past fifty years. In this work, the novel Hilbert-Huang transform approach is applied to investigate the yearly numbers of polar faculae in the time interval from 1705 to 1999. The detected periodicities can be allocated to three components: the first one is the short-term variations with periods smaller than 11 years, the second one is the mid- term variations with classical periods from 11 years to 50 years, and the last one is the long-term variations with periods larger than 50 years. The analysis results improve our knowledge on the quasi-periodic variations of solar magnetic activity and could be provided valuable constraints for solar dynamo theory. Furthermore, our analysis results could be useful for understanding the long-term variations of solar magnetic activity, providing crucial information to describe and forecast solar magnetic activity indicators.

  4. REGULARITY OF THE NORTH–SOUTH ASYMMETRY OF SOLAR ACTIVITY: REVISITED

    International Nuclear Information System (INIS)

    Zhang, J.; Feng, W.

    2015-01-01

    Extended time series of Solar Activity Indices (ESAI) extended the Greenwich series of sunspot area from the year 1874 back to 1821. The ESAI's yearly sunspot area in the northern and southern hemispheres from 1821 to 2013 is utilized to investigate characteristics of the north–south hemispherical asymmetry of sunspot activity. Periodical behavior of about 12 solar cycles is also confirmed from the ESAI data set to exist in dominant hemispheres, linear regression lines of yearly asymmetry values, and cumulative counts of yearly sunspot areas in the hemispheres for solar cycles. The period is also inferred to appear in both the cumulative difference in the yearly sunspot areas in the hemispheres over the entire time interval and in its statistical Student's t-test. The hemispherical bias of sunspot activity should be regarded as an impossible stochastic phenomenon over a long time period

  5. Models of the quiet and active solar atmosphere from Harvard OSO data.

    Science.gov (United States)

    Noyes, R. W.

    1971-01-01

    Review of some Harvard Observatory programs aimed at defining the physical conditions in quiet and active solar regions on the basis of data obtained from the OSO-IV and OSO-VI spacecraft. The spectral range covered is from 300 A to 1400 A. This spectral range consists of emission lines and continua from abundant elements such as hydrogen, helium, carbon, nitrogen, oxygen, silicon, magnesium, aluminum, neon, iron, and calcium in various ionization states ranging from neutral to 15 times ionized. The structure is discussed of the quiet solar atmosphere as deduced from center-to-limb behavior of spectral lines and continua formed in the chromosphere and corona. In reviewing investigations of solar active regions, it is shown that the structure of these regions varies in a complicated manner from point to point. The local structure is influenced by factors such as the magnetic field configuration within the active region and the age or evolutionary state of the region.

  6. Birthdates of patients affected by mental illness and solar activity: A study from Italy

    Science.gov (United States)

    Ventriglio, Antonio; Borelli, Albacenzina; Bellomo, Antonello; Lepore, Alberto

    2011-04-01

    PurposeThis epidemiologic study tested an hypothesized association between the year of birth of persons with major mental illnesses and solar activity over the past century. MethodsWe collected data on diagnoses and birthdates of psychiatric patients born between 1926 and 1975 (N = 1954) in south Italy for comparison to yearly solar activity as registered by the International Observatories. ResultsWe found a strong inverse correlation between high solar activity (HSA) and incidence of schizophrenia and bipolar disorder in a 20-year period whereas the incidence of non-affective/non-psychotic disorders was moderately associated with HSA in the same period. ConclusionsInterpretation of the observed correlations between HSA during years of birth and the incidence of mental illnesses remains unclear, but the findings encourage further study.

  7. Concurrent study of bottomside spread F and plasma bubble events in the equatorial ionosphere during solar maximum using digisonde and ROCSAT-1

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-12-01

    Full Text Available Data from the Jicamarca digisonde and the ROCSAT-1 satellite are employed to study the equatorial ionosphere on the west side of South America during April 1999-March 2000 for the concurrent bottomside spread F (BSSF and plasma bubble events. This study, using digisonde and ROCSAT-1 concurrently, is the first attempt to investigate the equatorial spread F. Results show that BSSF and plasma bubble observations appear frequently respectively in the summer (January, February, November, and December and in the equinoctial (March, April, September, and October months, respectively, but are both rarely observed in the winter (May-August months. The upward drift velocity during the concurrent BSSF and bubble observations has been determined to study the driving mechanism. This analysis shows that large vertical drift velocities favor BSSF and bubble formations in the equinoctial and summer months. Conversely, the smaller upward velocities during the winter months cause fewer BSSF and bubble occurrences. For the geomagnetic effect, the BSSF/bubble occurrence decreases with an increasing Kp value in the equinoctial months, but no such correlation is found for the summer and winter months. Moreover, the anti-correlations between Kp and dh'F/dt are apparent in the equinoctial months, but not in the summer and winter months. These results indicate that in the equinoctial months the BSSF/bubble generations and the pre-reversal drift velocity can be suppressed by geomagnetic activity, because the disturbance dynamo effects could have decreased the eastward electric field near sunset. However, BSSF and bubble occurrences may not be suppressed by the geomagnetic activity in the summer and winter months.

  8. Concurrent study of bottomside spread F and plasma bubble events in the equatorial ionosphere during solar maximum using digisonde and ROCSAT-1

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-12-01

    Full Text Available Data from the Jicamarca digisonde and the ROCSAT-1 satellite are employed to study the equatorial ionosphere on the west side of South America during April 1999-March 2000 for the concurrent bottomside spread F (BSSF and plasma bubble events. This study, using digisonde and ROCSAT-1 concurrently, is the first attempt to investigate the equatorial spread F. Results show that BSSF and plasma bubble observations appear frequently respectively in the summer (January, February, November, and December and in the equinoctial (March, April, September, and October months, respectively, but are both rarely observed in the winter (May-August months. The upward drift velocity during the concurrent BSSF and bubble observations has been determined to study the driving mechanism. This analysis shows that large vertical drift velocities favor BSSF and bubble formations in the equinoctial and summer months. Conversely, the smaller upward velocities during the winter months cause fewer BSSF and bubble occurrences. For the geomagnetic effect, the BSSF/bubble occurrence decreases with an increasing Kp value in the equinoctial months, but no such correlation is found for the summer and winter months. Moreover, the anti-correlations between Kp and dh'F/dt are apparent in the equinoctial months, but not in the summer and winter months. These results indicate that in the equinoctial months the BSSF/bubble generations and the pre-reversal drift velocity can be suppressed by geomagnetic activity, because the disturbance dynamo effects could have decreased the eastward electric field near sunset. However, BSSF and bubble occurrences may not be suppressed by the geomagnetic activity in the summer and winter months.

  9. How calibration and reference spectra affect the accuracy of absolute soft X-ray solar irradiance measured by the SDO/EVE/ESP during high solar activity

    Science.gov (United States)

    Didkovsky, Leonid; Wieman, Seth; Woods, Thomas

    2016-10-01

    The Extreme ultraviolet Spectrophotometer (ESP), one of the channels of SDO's Extreme ultraviolet Variability Experiment (EVE), measures solar irradiance in several EUV and soft x-ray (SXR) bands isolated using thin-film filters and a transmission diffraction grating, and includes a quad-diode detector positioned at the grating zeroth-order to observe in a wavelength band from about 0.1 to 7.0 nm. The quad diode signal also includes some contribution from shorter wavelength in the grating's first-order and the ratio of zeroth-order to first-order signal depends on both source geometry, and spectral distribution. For example, radiometric calibration of the ESP zeroth-order at the NIST SURF BL-2 with a near-parallel beam provides a different zeroth-to-first-order ratio than modeled for solar observations. The relative influence of "uncalibrated" first-order irradiance during solar observations is a function of the solar spectral irradiance and the locations of large Active Regions or solar flares. We discuss how the "uncalibrated" first-order "solar" component and the use of variable solar reference spectra affect determination of absolute SXR irradiance which currently may be significantly overestimated during high solar activity.

  10. Solar activity, tidal friction and the earth rotation over the last 2000 years

    International Nuclear Information System (INIS)

    Kiselev, V.M.

    1981-01-01

    The tidal retardations of the Earth rotation and orbital motion of the Moon on Dynamical Time are discussed. The secular deceleration of the lunar motion deduced from an analysis of the anciept and medieval eclipses is lapger thap that obtained from recent (telescopic) observations. This discrepancy is shown to vanish if the Earth acceleration due to secular change of solar activity is taken into consideration. Therefore, one may suggest that the mean tidal friction has remained essentially constant over the last two millennia. Nontidal variations of the Earth rotation velocity in the historical past as well as at present time are shown to be caused by solar activity changes [ru

  11. Study of solar activity by measuring cosmic rays with a water Cherenkov detector

    International Nuclear Information System (INIS)

    Bahena Bias, Angelica; Villasenor, Luis

    2011-01-01

    We report on an indirect study of solar activity by using the Forbush effect which consists on the anti-correlation between the intensity of solar activity and the intensity of secondary cosmic radiation detected at ground level at the Earth. We have used a cylindrical water Cherenkov detector to measure the rate of arrival of secondary cosmic rays in Morelia Mich., Mexico, at 1950 m.a.s.l. We describe the analysis required to unfold the effect of atmospheric pressure and the search for Forbush decreases in our data, the latter correspond to more than one year of continuous data collection.

  12. The technical analysis of the stock exchange and physics: Japanese candlesticks for solar activity

    Science.gov (United States)

    Dineva, C.; Atanasov, V.

    2013-09-01

    In this article, we use the Japanese candlesticks, a method popular in the technical analysis of the Stock/Forex markets and apply it to a variable in physics-the solar activity. This method is invented and used exclusively for economic analysis and its application to a physical problem produced unexpected results. We found that the Japanese candlesticks are convenient tool in the analysis of the variables in the physics of the Sun. Based on our observations, we differentiated a new cycle in the solar activity.

  13. Voc enhancement of a solar cell with doped Li+-PbS as the active layer

    Science.gov (United States)

    Chávez Portillo, M.; Alvarado Pulido, J.; Gallardo Hernández, S.; Soto Cruz, B. S.; Alcántara Iniesta, S.; Gutiérrez Pérez, R.; Portillo Moreno, O.

    2018-06-01

    In this report, we investigate the fabrication of solar cells obtained by chemical bath technique, based on CdS as window layer and PbS and PbS-Li+-doped as the active layer. We report open-circuit-voltage Voc values of ∼392 meV for PbS and ∼630 meV for PbSLi+-doped, a remarkable enhanced in the open circuit voltage is shown for solar cells with doped active layer. Li+ ion passivate the dangling bonds in PbS-metal layer interface in consequence reducing the recombination centers.

  14. Synthesis, characterization and photocatalytic activity of ZnO flower and pseudo-sphere: Nonylphenol ethoxylate degradation under UV and solar irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ashar, Ambreen [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Iqbal, Munawar, E-mail: bosalvee@yahoo.com [Department of Chemistry, Qurtuba University of Science and Information Technology, Peshawar 25100, KPK (Pakistan); Bhatti, Ijaz Ahmad; Ahmad, Muhammad Zubair; Qureshi, Khizar [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Nisar, Jan [National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120 (Pakistan); Bukhari, Iftikhar Hussain [Department of Chemistry, Government College University, Faisalabad (Pakistan)

    2016-09-05

    ZnO particles (flower and pseudo sphere) were synthesized via precipitation route and characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), Fourier transform infra-red (FTIR) spectroscopy, Atomic force microscopy (AFM), Particle size analyzer and UV–visible techniques. The photocatalytic activities (PCA) of ZnO flower (uncalcined) and pseudo-sphere (calcined) were evaluated by degrading nonylphenol ethoxylate-9 (NP9EO) under UV and solar irradiation. The process variables i.e., catalyst dose, calcination temperature, H{sub 2}O{sub 2} concentration, pH and UV/solar light exposure were investigated and under optimum conditions of process variables, paper, textile and leather industries effluents were also treated. Calcination at high temperature affected the morphology of ZnO particles. Both ZnO flower and pseudo-sphere degraded NP9EO and pollutants in industrial wastewater efficiently under both UV and solar irradiation. Maximum NP9EO degradation was achieved at 2.5 g/L catalyst dose, high calcination temperature, 4% H{sub 2}O{sub 2} concentration, 6 pH, 110 UV exposure and 12 h solar light exposure. Results reveal that ZnO is efficient photo-catalyst and could be used under solar irradiation for photocatalytic application by tuning the band gap. - Highlights: • ZnO flower and pseudo-spheres were synthesized via precipitation route. • The photocatalytic activities by degrading surfactant. • ZnO particles showed considerable photocatalytic activity under UV and solar irradiation. • By tuning the band gap of ZnO absorption capacity can be enhanced.

  15. Periodic analysis of solar activity and its link with the Arctic oscillation phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Weizheng; Li, Chun; Du, Ling; Huang, Fei [Ocean University of China, 14-1' -601, 2117 Jinshui Road, Qingdao 266100 (China); Li, Yanfang, E-mail: quweizhe@ouc.edu.cn [Yantai Institute of Coastal Zone Research Chinese Academy of Sciences (China)

    2014-12-01

    Based on spectrum analysis, we provide the arithmetic expressions of the quasi 11 yr cycle, 110 yr century cycle of relative sunspot numbers, and quasi 22 yr cycle of solar magnetic field polarity. Based on a comparative analysis of the monthly average geopotential height, geopotential height anomaly, and temperature anomaly of the northern hemisphere at locations with an air pressure of 500 HPa during the positive and negative phases of AO (Arctic Oscillation), one can see that the abnormal warming period in the Arctic region corresponds to the negative phase of AO, while the anomalous cold period corresponds to its positive phase. This shows that the abnormal change in the Arctic region is an important factor in determining the anomalies of AO. In accordance with the analysis performed using the successive filtering method, one can see that the AO phenomenon occurring in January shows a clear quasi 88 yr century cycle and quasi 22 yr decadal cycle, which are closely related to solar activities. The results of our comparative analysis show that there is a close inverse relationship between the solar activities (especially the solar magnetic field index changes) and the changes in the 22 yr cycle of the AO occurring in January, and that the two trends are basically opposite of each other. That is to say, in most cases after the solar magnetic index MI rises from the lowest value, the solar magnetic field turns from north to south, and the high-energy particle flow entering the Earth's magnetosphere increases to heat the polar atmosphere, thus causing the AO to drop from the highest value; after the solar magnetic index MI drops from the highest value, the solar magnetic field turns from south to north, and the solar high-energy particle flow passes through the top of the Earth's magnetosphere rather than entering it to heat the polar atmosphere. Thus the polar temperature drops, causing the AO to rise from the lowest value. In summary, the variance

  16. Synthesis of activated charcoal supported Bi-doped TiO{sub 2} nanocomposite under solar light irradiation for enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Chandraboss, V.L.; Kamalakkannan, J.; Senthilvelan, S., E-mail: dr_senthilvel@yahoo.co.in

    2016-11-30

    Highlights: • Particle size and band gap of TiO{sub 2} is decreased upon Bi doping. • Methylene blue is successfully degraded over Bi/TiO{sub 2} and AC-Bi/TiO{sub 2}. • AC-Bi/TiO{sub 2} is more active photocatalyst than TiO{sub 2} and Bi/TiO{sub 2}. • AC-Bi/TiO{sub 2} led to a maximum extension of the spectral wavelength. • AC-Bi/TiO{sub 2} with enhanced photocatalytic activity produced much more reactive ·OH. - Abstract: In this study, activated charcoal (AC) supported bismuth (Bi)-doped Titanium dioxide (TiO{sub 2}) nanocomposite was synthesized by precipitation method. The photocatalytic activity of AC-Bi/TiO{sub 2} was investigated for the degradation of methylene blue (MB) in aqueous solution under solar light irradiation. The incorporation of Bi{sup 3+} into the TiO{sub 2} lattice shifts the absorbance of TiO{sub 2} to the visible region then the addition of high adsorption capacity activated charcoal to improve the efficiency of TiO{sub 2}. AC-Bi/TiO{sub 2} is found to be more efficient than Bi/TiO{sub 2} and undoped TiO{sub 2} for the degradation of MB under solar light irradiation. Surface morphology and bulk composition of the composite was obtained using high resolution-scanning electron microscopy with energy dispersive X-ray analysis. The crystal structure evolution and elemental composition were analyzed by combining Fourier transform-Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The ultraviolet-visible (UV–vis) absorption spectra show that the absorption edge for the composite with Bi{sup 3+} has red shift as compared with that of undoped TiO{sub 2}. UV–vis diffuse reflectance spectra demonstrated a decrease in the direct band gap of AC-Bi/TiO{sub 2}. BET surface area, pore radius and pore volume of the materials were calculated by applying the BET equation to the sorption isotherms. The production of hydroxyl radicals (·OH) on the surface of solar light irradiated materialswere detected by

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

    DEFF Research Database (Denmark)

    Strugarek, Antoine; Janitzek, Nils; Lee, Arrow

    2015-01-01

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

  18. A Remarkable Recent Transition in the Solar Dynamo

    NARCIS (Netherlands)

    de Jager, C.; Akasofu, S.-I.; Duhau, S.; Livingston, W.C.; Nieuwenhuijzen, H.; Potgieter, M.S.

    2016-01-01

    We summarize the major aspects of the remarkable, fairly long lasting period(∼ 2005 to ∼ 2010) of low solar activity, that we will call the Transition. It is the transitionalstage between the Grand Maximum of the 20th century and a forthcoming (most probablyRegular) episode of solar activity. The

  19. Sunspot variation and selected associated phenomena: a look at solar cycle 21 and beyond

    International Nuclear Information System (INIS)

    Wilson, R.M.

    1982-02-01

    Solar sunspot cycles 8 through 21 are reviewed. Mean time intervals are calculated for maximum to maximum, minimum to minimum, minimum to maximum, and maximum to minimum phases for cycles 8 through 20 and 8 through 21. Simple cosine functions with a period of 132 years are compared to, and found to be representative of, the variation of smoothed sunspot numbers at solar maximum and minimum. A comparison of cycles 20 and 21 is given, leading to a projection for activity levels during the Spacelab 2 era (tentatively, November 1984). A prediction is made for cycle 22. Major flares are observed to peak several months subsequent to the solar maximum during cycle 21 and to be at minimum level several months after the solar minimum. Additional remarks are given for flares, gradual rise and fall radio events and 2800 MHz radio emission. Certain solar activity parameters, especially as they relate to the near term Spacelab 2 time frame are estimated

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-20

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

  1. Coronal Radio Sounding Experiments with Mars Express: Scintillation Spectra during Low Solar Activity

    International Nuclear Information System (INIS)

    Efimov, A. I.; Lukanina, L. A.; Samoznaev, L. N.; Rudash, V. K.; Chashei, I. V.; Bird, M. K.; Paetzold, M.; Tellmann, S.

    2010-01-01

    Coronal radio sounding observations were carried out with the radio science experiment MaRS on the ESA spacecraft Mars Express during the period from 25 August to 22 October 2004. Differential frequency and log-amplitude fluctuations of the dual-frequency signals were recorded during a period of low solar activity. The data are applicable to low heliographic latitudes, i.e. to slow solar wind. The mean frequency fluctuation and power law index of the frequency fluctuation temporal spectra are determined as a function of heliocentric distance. The radial dependence of the frequency fluctuation spectral index α reflects the previously documented flattening of the scintillation power spectra in the solar wind acceleration region. Temporal spectra of S-band and X-band normalized log-amplitude fluctuations were investigated over the range of fluctuation frequencies 0.01 Hz<ν<0.5 Hz, where the spectral density is approximately constant. The radial variation of the spectral density is analyzed and compared with Ulysses 1991 data, a period of high solar activity. Ranging measurements are presented and compared with frequency and log-amplitude scintillation data. Evidence for a weak increase in the fractional electron density turbulence level is obtained in the range 10-40 solar radii.

  2. Commercially Available Activated Carbon Fiber Felt Enables Efficient Solar Steam Generation.

    Science.gov (United States)

    Li, Haoran; He, Yurong; Hu, Yanwei; Wang, Xinzhi

    2018-03-21

    Sun-driven steam generation is now possible and has the potential to help meet future energy needs. Current technologies often use solar condensers to increase solar irradiance. More recently, a technology for solar steam generation that uses heated surface water and low optical concentration is reported. In this work, a commercially available activated carbon fiber felt is used to generate steam efficiently under one sun illumination. The evaporation rate and solar conversion efficiency reach 1.22 kg m -2 h -1 and 79.4%, respectively. The local temperature of the evaporator with a floating activated carbon fiber felt reaches 48 °C. Apart from the high absorptivity (about 94%) of the material, the evaporation performance is enhanced thanks to the well-developed pores for improved water supply and steam escape and the low thermal conductivity, which enables reduced bulk water temperature increase. This study helps to find a promising material for solar steam generation using a water evaporator that can be produced economically (∼6 $/m 2 ) with long-term stability.

  3. Relationships between the solar wind and the polar cap magnetic activity

    International Nuclear Information System (INIS)

    Berthelier, A.

    1981-01-01

    The influence of solar wind conditions on magnetic activity is described in order to delineate the differences in the response of the magnetic activity to the arrival on the magnetopause of different typical solar wind variations. By determining a new index of local magnetic activity free from seasonal and diurnal effects we put in evidence the dependence of the various effects upon the invariant latitude. Most important results are: (1) the main increase of the magnetic activity does not occur at the same invariant latitude for different interplanetary variations, e.g. peaks of Bz tend to increase magnetic activity mainly in the auroral zones while peaks of B correspond to a uniform increase in magnetic activity over the polar cap and auroral zone; (2) there is a two steps response of magnetic activity to the high speed plasma streams; (3) an increase of magnetic activity is observed for large and northward Bz, which probably indicates that the solar wind-magnetosphere coupling is efficient under these circumstances. The specific influences of the IMF polarity are also briefly reviewed. (orig.)

  4. STATISTICAL ANALYSIS OF ACOUSTIC WAVE PARAMETERS NEAR SOLAR ACTIVE REGIONS

    International Nuclear Information System (INIS)

    Rabello-Soares, M. Cristina; Bogart, Richard S.; Scherrer, Philip H.

    2016-01-01

    In order to quantify the influence of magnetic fields on acoustic mode parameters and flows in and around active regions, we analyze the differences in the parameters in magnetically quiet regions nearby an active region (which we call “nearby regions”), compared with those of quiet regions at the same disk locations for which there are no neighboring active regions. We also compare the mode parameters in active regions with those in comparably located quiet regions. Our analysis is based on ring-diagram analysis of all active regions observed by the Helioseismic and Magnetic Imager (HMI) during almost five years. We find that the frequency at which the mode amplitude changes from attenuation to amplification in the quiet nearby regions is around 4.2 mHz, in contrast to the active regions, for which it is about 5.1 mHz. This amplitude enhacement (the “acoustic halo effect”) is as large as that observed in the active regions, and has a very weak dependence on the wave propagation direction. The mode energy difference in nearby regions also changes from a deficit to an excess at around 4.2 mHz, but averages to zero over all modes. The frequency difference in nearby regions increases with increasing frequency until a point at which the frequency shifts turn over sharply, as in active regions. However, this turnover occurs around 4.9 mHz, which is significantly below the acoustic cutoff frequency. Inverting the horizontal flow parameters in the direction of the neigboring active regions, we find flows that are consistent with a model of the thermal energy flow being blocked directly below the active region.

  5. Decadal Cycles of Earth Rotation, Mean Sea Level and Climate, Excited by Solar Activity

    Czech Academy of Sciences Publication Activity Database

    Chapanov, Y.; Ron, Cyril; Vondrák, Jan

    2017-01-01

    Roč. 14, č. 2 (2017), s. 241-250 ISSN 1214-9705 R&D Projects: GA ČR GA13-15943S Institutional support: RVO:67985815 Keywords : Earth rotation * solar activity * mean sea level Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 0.699, year: 2016

  6. Status report on preliminary design activities for solar heating and cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    1978-05-01

    Information presented provides status and progress on the development of solar heating and cooling systems. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities as part of the contract requirements.

  7. Evidence from northwest European bogs shows ‘Little Ice Age’ climatic changes driven by variations in solar activity

    NARCIS (Netherlands)

    Mauquoy, D; van Geel, B; Blaauw, Maarten; van der Plicht, J

    2002-01-01

    Fluctuations in Holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity. Analyses of both Be-10 and C-14 nuclides confirm that production-rate changes during the Holocene were largely modulated by solar activity. Analyses of peat samples from two

  8. A climatological study of the relations among solar activity, galactic ...

    Indian Academy of Sciences (India)

    activity, galactic cosmic ray and precipitation on various regions .... mate variations to cosmic rays and the physical- chemical .... For the wavelet spectrum, significance level for each ..... monthly climate for Europe and the globe: The observed.

  9. Study of the Effect of Active Regions on the Scattering Polarization in the Solar Corona

    Science.gov (United States)

    Derouich, M.; Badruddin

    2018-03-01

    The solar photospheric/chromospheric light exciting atoms/ions is not homogeneous because of the presence of active regions (ARs). The effect of ARs on the scattering polarization at the coronal level is an important ingredient for a realistic determination of the magnetic field. This effect is usually disregarded or mixed with other effects in the sense that the degree of its importance is not well known. The aim of this paper is to study the effect of atmospheric inhomogeneities on the coronal scattering polarization. We determined quantitatively the importance of the atmospheric inhomogeneities by using given geometries of solar ARs (plages and sunspots).

  10. Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

    Science.gov (United States)

    Bruner, M.; Brown, W. A.; Haisch, B. M.

    1987-01-01

    A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft X-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the X-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical X-ray observations using this new technique.

  11. Improved Power Conversion Efficiency of Inverted Organic Solar Cells by Incorporating Au Nanorods into Active Layer.

    Science.gov (United States)

    He, Yeyuan; Liu, Chunyu; Li, Jinfeng; Zhang, Xinyuan; Li, Zhiqi; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-07-29

    This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversion efficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

  12. [Fluctuations in biophysical measurements as a result of variations in solar activity].

    Science.gov (United States)

    Peterson, T F

    1995-01-01

    A theory is proposed to explain variations in the net electrical charge of biological substances at the Earth's surface. These are shown to occur in association with changes in the solar wind and geomagnetic field. It is suggested that a liquid dielectric's net volume charge will imitate pH effects, influence chemical reaction rates, and alter ion transfer mechanisms in biophysical systems. An experiment is described which measures dielectric volume charge, or non-neutrality, to allow correlation of this property with daily, 28-day, and 11-year fluctuation patterns in geophysical and satellite data associated with solar activity and the interplanetary magnetic field.

  13. Solar Indices

    Data.gov (United States)

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

  14. Ancient cellular structures and modern humans: change of survival strategies before prolonged low solar activity period

    Science.gov (United States)

    Ragulskaya, Mariya; Rudenchik, Evgeniy; Gromozova, Elena; Voychuk, Sergei; Kachur, Tatiana

    The study of biotropic effects of modern space weather carries the information about the rhythms and features of adaptation of early biological systems to the outer space influence. The influence of cosmic rays, ultraviolet waves and geomagnetic field on early life has its signs in modern biosphere processes. These phenomena could be experimentally studied on present-day biological objects. Particularly inorganic polyphosphates, so-called "fossil molecules", attracts special attention as the most ancient molecules which arose in inanimate nature and have been accompanying biological objects at all stages of evolution. Polyphosphates-containing graves of yeast's cells of Saccharomyces cerevisiae strain Y-517, , from the Ukrainian Collection of Microorganisms was studied by daily measurements during 2000-2013 years. The IZMIRAN daily data base of physiological parameters dynamics during 2000-2013 years were analyzed simultaneously (25 people). The analysis showed significant simultaneous changes of the statistical parameters of the studied biological systems in 2004 -2006. The similarity of simultaneous changes of adaptation strategies of human organism and the cell structures of Saccharomyces cerevisiae during the 23-24 cycles of solar activity are discussed. This phenomenon could be due to a replacement of bio-effective parameters of space weather during the change from 23rd to 24th solar activity cycle and nonstandard geophysical peculiarities of the 24th solar activity cycle. It could be suggested that the observed similarity arose as the optimization of evolution selection of the living systems in expectation of probable prolonged period of low solar activity (4-6 cycles of solar activity).

  15. Survey of active solar thermal collectors, industry and markets in Canada : final report

    International Nuclear Information System (INIS)

    2005-08-01

    A survey of the solar thermal industry in Canada was presented. The aim of the survey was to determine the size of the Canadian solar thermal industry and market. Data were used to derive thermal energy output as well as avoided greenhouse gas (GHG) emissions from solar thermal systems. The questionnaire was distributed to 268 representatives. Results revealed annual sales of 24.2, 26.4 and 37.5 MW TH in 2002, 2003, and 2004 respectively, which represented over 50 per cent growth in the operating base during the 3 year survey period. Sales of all collector types grew substantially during the 3 year period, and survey respondents anticipated 20 per cent growth in both 2005 and 2006. Approximately 10 per cent of all sales were exported during 2002-2004. Unglazed liquid collectors constituted the majority of collector types sold in Canada, almost all of which were sold into the residential sector for swimming pool heating. The majority of air collectors were sold into the industrial/commercial and institutional (I/CI) sectors for use in space heating. Sales of liquid glazed and evacuated tube collectors were split between the residential and I/CI sectors. Residential sales were primarily for domestic water heating. In 2004, 23 per cent of sales in the residential sector were for combination domestic hot water and space heating applications, an indication of strong growth. Results of the survey indicated that the solar thermal market in Quebec differed from other regions, with more than double the annual per capita revenue of any other region as a result of greater market penetration of unglazed air collectors. Calculations of the GHG emissions avoided due to active solar thermal systems were made based on historical estimates of solar thermal installations. A model was developed to calculate an operating base by collector type from 1979 to the present. The model showed that many of the systems installed during the 1980s were decommissioned during the 1990s, and that

  16. Survey of active solar thermal collectors, industry and markets in Canada : final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-08-01

    A survey of the solar thermal industry in Canada was presented. The aim of the survey was to determine the size of the Canadian solar thermal industry and market. Data were used to derive thermal energy output as well as avoided greenhouse gas (GHG) emissions from solar thermal systems. The questionnaire was distributed to 268 representatives. Results revealed annual sales of 24.2, 26.4 and 37.5 MW{sub TH} in 2002, 2003, and 2004 respectively, which represented over 50 per cent growth in the operating base during the 3 year survey period. Sales of all collector types grew substantially during the 3 year period, and survey respondents anticipated 20 per cent growth in both 2005 and 2006. Approximately 10 per cent of all sales were exported during 2002-2004. Unglazed liquid collectors constituted the majority of collector types sold in Canada, almost all of which were sold into the residential sector for swimming pool heating. The majority of air collectors were sold into the industrial/commercial and institutional (I/CI) sectors for use in space heating. Sales of liquid glazed and evacuated tube collectors were split between the residential and I/CI sectors. Residential sales were primarily for domestic water heating. In 2004, 23 per cent of sales in the residential sector were for combination domestic hot water and space heating applications, an indication of strong growth. Results of the survey indicated that the solar thermal market in Quebec differed from other regions, with more than double the annual per capita revenue of any other region as a result of greater market penetration of unglazed air collectors. Calculations of the GHG emissions avoided due to active solar thermal systems were made based on historical estimates of solar thermal installations. A model was developed to calculate an operating base by collector type from 1979 to the present. The model showed that many of the systems installed during the 1980s were decommissioned during the 1990s, and

  17. The influence of active region information on the prediction of solar flares: an empirical model using data mining

    Directory of Open Access Journals (Sweden)

    M. Núñez

    2005-11-01

    Full Text Available Predicting the occurrence of solar flares is a challenge of great importance for many space weather scientists and users. We introduce a data mining approach, called Behavior Pattern Learning (BPL, for automatically discovering correlations between solar flares and active region data, in order to predict the former. The goal of BPL is to predict the interval of time to the next solar flare and provide a confidence value for the associated prediction. The discovered correlations are described in terms of easy-to-read rules. The results indicate that active region dynamics is essential for predicting solar flares.

  18. Influence of solar activity and environment on 10Be in recent natural archives

    International Nuclear Information System (INIS)

    Berggren, Ann-Marie

    2009-01-01

    Understanding the link between the Sun and climate is vital in the current incidence of global climate change, and 10 Be in natural archives constitutes an excellent tracer for this purpose. As cosmic rays enter the atmosphere, cosmogenic isotopes like 10 Be and 14 C are formed. Variations in solar activity modulate the amount of incoming cosmic rays, and thereby cosmogenic isotope production. Atmospherically produced 10 Be enters natural archives such as sediments and glaciers by wet and dry deposition within about a year of production. 10 Be from natural archives therefore provides information on past solar activity, and because these archives also contain climate information, solar activity and climate can be linked. One remaining question is to what degree 10 Be in natural archives reflects production, and to what extent the local and regional environment overprints the production signal. To explore this, 10 Be was measured at annual resolution over the last 600 years in a Greenland ice core. Measurement potentials for these samples benefited from the development of a new laboratory method of co-precipitating 10 Be with niobium. To diversify geographic location and archive media type, a pioneer study of measuring 10 Be with annual resolution in varved lake sediments from Finland was conducted, with samples from the entire 20th century. Pathways of 10 Be into lake sediments are more complex than into glacial ice, inferring that contemporary atmospheric conditions may not be recorded. Here, it is shown for the first time that tracing the 11-year solar cycle through lake sediment 10 Be variations is possible. Results also show that on an annual basis, 10 Be deposition in ice and sediment archives is affected by local environmental conditions. On a slightly longer timescale, however, diverse 10 Be records exhibit similar trends and a negative correlation with solar activity. Cyclic variability of 10 Be deposition persisted throughout past grand solar minima, when

  19. Variability of fractal dimension of solar radio flux

    Science.gov (United States)

    Bhatt, Hitaishi; Sharma, Som Kumar; Trivedi, Rupal; Vats, Hari Om

    2018-04-01

    In the present communication, the variation of the fractal dimension of solar radio flux is reported. Solar radio flux observations on a day to day basis at 410, 1415, 2695, 4995, and 8800 MHz are used in this study. The data were recorded at Learmonth Solar Observatory, Australia from 1988 to 2009 covering an epoch of two solar activity cycles (22 yr). The fractal dimension is calculated for the listed frequencies for this period. The fractal dimension, being a measure of randomness, represents variability of solar radio flux at shorter time-scales. The contour plot of fractal dimension on a grid of years versus radio frequency suggests high correlation with solar activity. Fractal dimension increases with increasing frequency suggests randomness increases towards the inner corona. This study also shows that the low frequency is more affected by solar activity (at low frequency fractal dimension difference between solar maximum and solar minimum is 0.42) whereas, the higher frequency is less affected by solar activity (here fractal dimension difference between solar maximum and solar minimum is 0.07). A good positive correlation is found between fractal dimension averaged over all frequencies and yearly averaged sunspot number (Pearson's coefficient is 0.87).

  20. IPS observations of transient interplanetary phenomena associated with solar filament activity in late august

    International Nuclear Information System (INIS)

    Watanabe, Takashi; Marubashi, Katsuhide.

    1985-01-01

    Large-scale structures of the solar wind plasma during the severe geomagnetic storm of August 27-29, 1978 are studied on the basis of IPS and spacecraft observations. Three-dimensional configuration of an interplanetary disturbance which caused the SSC of August 27, 1978 was an oblate sphere having an axial ratio of 1.7. Approximate excess mass and kinetic energy contained within the high-speed portion of the disturbance (--500 km s -1 ) were 10 16 g and 3 x 10 31 erg, respectively. An interplanetary disturbance was also observed on August 28, 1978 during the main phase of the geomagnetic storm. It is suggested that the solar-filament activity which took place near the solar disk center in August 23-25, 1978 caused these interplanetary disturbances. (author)

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

    International Nuclear Information System (INIS)

    Kazimirovsky, E.S.

    1989-01-01

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

  2. Life cycle cost analysis of single slope hybrid (PV/T) active solar still

    International Nuclear Information System (INIS)

    Kumar, Shiv; Tiwari, G.N.

    2009-01-01

    This paper presents the life cycle cost analysis of the single slope passive and hybrid photovoltaic (PV/T) active solar stills, based on the annual performance at 0.05 m water depth. Effects of various parameters, namely interest rate, life of the system and the maintenance cost have been taken into account. The comparative cost of distilled water produced from passive solar still (Rs. 0.70/kg) is found to be less than hybrid (PV/T) active solar still (Rs. 1.93/kg) for 30 years life time of the systems. The payback periods of the passive and hybrid (PV/T) active solar still are estimated to be in the range of 1.1-6.2 years and 3.3-23.9 years, respectively, based on selling price of distilled water in the range of Rs. 10/kg to Rs. 2/kg. The energy payback time (EPBT) has been estimated as 2.9 and 4.7 years, respectively. (author)

  3. Particle acceleration in solar active regions being in the state of self-organized criticality.

    Science.gov (United States)

    Vlahos, Loukas

    We review the recent observational results on flare initiation and particle acceleration in solar active regions. Elaborating a statistical approach to describe the spatiotemporally intermittent electric field structures formed inside a flaring solar active region, we investigate the efficiency of such structures in accelerating charged particles (electrons and protons). The large-scale magnetic configuration in the solar atmosphere responds to the strong turbulent flows that convey perturbations across the active region by initiating avalanche-type processes. The resulting unstable structures correspond to small-scale dissipation regions hosting strong electric fields. Previous research on particle acceleration in strongly turbulent plasmas provides a general framework for addressing such a problem. This framework combines various electromagnetic field configurations obtained by magnetohydrodynamical (MHD) or cellular automata (CA) simulations, or by employing a statistical description of the field’s strength and configuration with test particle simulations. We work on data-driven 3D magnetic field extrapolations, based on a self-organized criticality models (SOC). A relativistic test-particle simulation traces each particle’s guiding center within these configurations. Using the simulated particle-energy distributions we test our results against observations, in the framework of the collisional thick target model (CTTM) of solar hard X-ray (HXR) emission and compare our results with the current observations.

  4. Understanding the origin of the solar cyclic activity for an improved earth climate prediction

    Science.gov (United States)

    Turck-Chièze, Sylvaine; Lambert, Pascal

    This review is dedicated to the processes which could explain the origin of the great extrema of the solar activity. We would like to reach a more suitable estimate and prediction of the temporal solar variability and its real impact on the Earth climatic models. The development of this new field is stimulated by the SoHO helioseismic measurements and by some recent solar modelling improvement which aims to describe the dynamical processes from the core to the surface. We first recall assumptions on the potential different solar variabilities. Then, we introduce stellar seismology and summarize the main SOHO results which are relevant for this field. Finally we mention the dynamical processes which are presently introduced in new solar models. We believe that the knowledge of two important elements: (1) the magnetic field interplay between the radiative zone and the convective zone and (2) the role of the gravity waves, would allow to understand the origin of the grand minima and maxima observed during the last millennium. Complementary observables like acoustic and gravity modes, radius and spectral irradiance from far UV to visible in parallel to the development of 1D-2D-3D simulations will improve this field. PICARD, SDO, DynaMICCS are key projects for a prediction of the next century variability. Some helioseismic indicators constitute the first necessary information to properly describe the Sun-Earth climatic connection.

  5. From Emergence to Eruption: The Physics and Diagnostics of Solar Active Regions

    Science.gov (United States)

    Cheung, Mark

    2017-08-01

    The solar photosphere is continuously seeded by the emergence of magnetic fields from the solar interior. In turn, photospheric evolution shapes the magnetic terrain in the overlying corona. Magnetic fields in the corona store the energy needed to power coronal mass ejections (CMEs) and solar flares. In this talk, we recount a physics-based narrative of solar eruptive events from cradle to grave, from emergence to eruption, from evaporation to condensation. We review the physical processes which are understood to transport magnetic flux from the interior to the surface, inject free energy and twist into the corona, disentangle the coronal field to permit explosive energy release, and subsequently convert the released energy into observable signatures. Along the way, we review observational diagnostics used to constrain theories of active region evolution and eruption. Finally, we discuss the opportunities and challenges enabled by the large existing repository of solar observations. We argue that the synthesis of physics and diagnostics embodied in (1) data-driven modeling and (2) machine learning efforts will be an accelerating agent for scientific discovery.

  6. Heliophysics: Evolving Solar Activity and the Climates of Space and Earth

    Science.gov (United States)

    Schrijver, Carolus J.; Siscoe, George L.

    2012-01-01

    Preface; 1. Interconnectedness in heliophysics Carolus J. Schrijver and George L. Siscoe; 2. Long-term evolution of magnetic activity of Sun-like stars Carolus J. Schrijver; 3. Formation and early evolution of stars and proto-planetary disks Lee W. Hartmann; 4. Planetary habitability on astronomical time scales Donald E. Brownlee; 5. Solar internal flows and dynamo action Mark S. Miesch; 6. Modeling solar and stellar dynamos Paul Charbonneau; 7. Planetary fields and dynamos Ulrich R. Christensen; 8. The structure and evolution of the 3D solar wind John T. Gosling; 9. The heliosphere and cosmic rays J. Randy Jokipii; 10. Solar spectral irradiance: measurements and models Judith L. Lean and Thomas N. Woods; 11. Astrophysical influences on planetary climate systems Juerg Beer; 12. Evaluating the drivers of Earth's climate system Thomas J. Crowley; 13. Ionospheres of the terrestrial planets Stanley C. Solomon; 14. Long-term evolution of the geospace climate Jan J. Sojka; 15. Waves and transport processes in atmospheres and oceans Richard L. Walterscheid; 16. Solar variability, climate, and atmospheric photochemistry Guy P. Brasseur, Daniel Marsch and Hauke Schmidt; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

  7. Solar and Stellar Active Regions:Cosmic laboratories for the study of Complexity

    OpenAIRE

    Vlahos, Loukas

    2008-01-01

    Solar active regions are driven dissipative dynamical systems. The turbulent convection zone forces new magnetic flux tubes to rise above the photosphere and shuffles the magnetic fields which are already above the photosphere. The driven 3D active region responds to the driver with the formation of Thin Current Sheets in all scales and releases impulsively energy, when special thresholds are met, on the form of nano-, micro-, flares and large scale coronal mass ejections. It has been documen...

  8. Cosmogenic radionuclide 7Be in atmospheric fallouts, weather factors and solar activity

    International Nuclear Information System (INIS)

    Kungurov, F.R.

    2011-11-01

    Key words: 7 Be activity, atmospheric fallouts, solar activity, gamma spectroscopy. Subjects of research: cosmogenic radionuclide 7 Be in atmospheric fallouts and surrounding objects of environment, its migrational distribution connected to solar activity and weather meteorologic parameters of the region studied. Purpose of work: Defining correlation between atmospheric humidity and solar activity with concentration and distribution of cosmogenic radionuclide 7 Be. Methods of research: gamma-spectrometry method of activity measurements. The results obtained and their novelty: Cycle of research works on definition of concentration and migrational distribution of CRN 7 Be in Samarkand region during 2002-2005 was carried out for the first time. Volumetric activity of 7 Be in squat air layer of Samarkand was determined. Average density of 7 Be fallouts for the four years of studies was determined. Qualitative correlation bet ween 7 Be fallouts density variations and solar activity, expressed through Wolf number has been found. Qualitative correlation between 7 Be fallouts density variations and amount of precipitations has been found. Regularity in 7 Be concentration decrease towards north latitudes has been detected. Practical value: Developed scintillation method of 7 Be activity detection in atmospheric fallouts was used in works performed in the framework of republican grants 2F-No 1.2.3, CNT RUz PFNI 2F-No 2.1.39 and ITD-7-024. Methodology was used for the estimation of the velocity of erosion processes in the soils of different regions of Uzbekistan. Methodology is used in the works on 7 Be radioactivity measurements. Degree of embed and economic effectivity: Gained results replenish database on 7 Be isotope distribution on Earth regions and its role in formation of some processes, connected with meteorology, agronomy and radioecology of Samarkand region. Field of application: meteorology, agronomy and radioecology. (author)

  9. What can the annual 10Be solar activity reconstructions tell us about historic space weather?

    Science.gov (United States)

    Barnard, Luke; McCracken, Ken G.; Owens, Mat J.; Lockwood, Mike

    2018-04-01

    Context: Cosmogenic isotopes provide useful estimates of past solar magnetic activity, constraining past space climate with reasonable uncertainty. Much less is known about past space weather conditions. Recent advances in the analysis of 10Be by McCracken & Beer (2015, Sol Phys 290: 305-3069) (MB15) suggest that annually resolved 10Be can be significantly affected by solar energetic particle (SEP) fluxes. This poses a problem, and presents an opportunity, as the accurate quantification of past solar magnetic activity requires the SEP effects to be determined and isolated, whilst doing so might provide a valuable record of past SEP fluxes. Aims: We compare the MB15 reconstruction of the heliospheric magnetic field (HMF), with two independent estimates of the HMF derived from sunspot records and geomagnetic variability. We aim to quantify the differences between the HMF reconstructions, and speculate on the origin of these differences. We test whether the differences between the reconstructions appear to depend on known significant space weather events. Methods: We analyse the distributions of the differences between the HMF reconstructions. We consider how the differences vary as a function of solar cycle phase, and, using a Kolmogorov-Smirnov test, we compare the distributions under the two conditions of whether or not large space weather events were known to have occurred. Results: We find that the MB15 reconstructions are generally marginally smaller in magnitude than the sunspot and geomagnetic HMF reconstructions. This bias varies as a function of solar cycle phase, and is largest in the declining phase of the solar cycle. We find that MB15's excision of the years with very large ground level enhancement (GLE) improves the agreement of the 10Be HMF estimate with the sunspot and geomagnetic reconstructions. We find no statistical evidence that GLEs, in general, affect the MB15 reconstruction, but this analysis is limited by having too few samples. We do find

  10. Multi-wavelength Observations of Solar Acoustic Waves Near Active Regions

    Science.gov (United States)

    Monsue, Teresa; Pesnell, Dean; Hill, Frank

    2018-01-01

    Active region areas on the Sun are abundant with a variety of waves that are both acoustically helioseismic and magnetohydrodynamic in nature. The occurrence of a solar flare can disrupt these waves, through MHD mode-mixing or scattering by the excitation of these waves. We take a multi-wavelength observational approach to understand the source of theses waves by studying active regions where flaring activity occurs. Our approach is to search for signals within a time series of images using a Fast Fourier Transform (FFT) algorithm, by producing multi-frequency power map movies. We study active regions both spatially and temporally and correlate this method over multiple wavelengths using data from NASA’s Solar Dynamics Observatory. By surveying the active regions on multiple wavelengths we are able to observe the behavior of these waves within the Solar atmosphere, from the photosphere up through the corona. We are able to detect enhancements of power around active regions, which could be acoustic power halos and of an MHD-wave propagating outward by the flaring event. We are in the initial stages of this study understanding the behaviors of these waves and could one day contribute to understanding the mechanism responsible for their formation; that has not yet been explained.

  11. Relative phase asynchrony and long-range correlation of long-term solar magnetic activity

    Science.gov (United States)

    Deng, Linhua

    2017-07-01

    Statistical signal processing is one of the most important tasks in a large amount of areas of scientific studies, such as astrophysics, geophysics, and space physics. Phase recurrence analysis and long-range persistence are the two dynamical structures of the underlying processes for the given natural phenomenon. Linear and nonlinear time series analysis approaches (cross-correlation analysis, cross-recurrence plot, wavelet coherent transform, and Hurst analysis) are combined to investigate the relative phase interconnection and long-range correlation between solar activity and geomagnetic activity for the time interval from 1932 January to 2017 January. The following prominent results are found: (1) geomagnetic activity lags behind sunspot numbers with a phase shift of 21 months, and they have a high level of asynchronous behavior; (2) their relative phase interconnections are in phase for the periodic scales during 8-16 years, but have a mixing behavior for the periodic belts below 8 years; (3) both sunspot numbers and geomagnetic activity can not be regarded as a stochastic phenomenon because their dynamical behaviors display a long-term correlation and a fractal nature. We believe that the presented conclusions could provide further information on understanding the dynamical coupling of solar dynamo process with geomagnetic activity variation, and the crucial role of solar and geomagnetic activity in the long-term climate change.

  12. Our Solar Connection: A themed Set of Activities for Grades 5-12

    Science.gov (United States)

    van der Veen, W. E.; Gary, D. E.; Gallagher, A. C.; Vinski, J. M.

    2005-12-01

    The project is a partnership between the Center for Solar-Terrestrial Research at New Jersey Institute of Technology (NJIT), and the New Jersey Astronomy Center for Education (NJACE) at Raritan Valley Community College. It was supported by a NASA Education/Public Outreach grant from the Office of Space Science. The project involved the development of a set of seven activities connected by the theme of solar magnetism and designed to meet the New Jersey Science Process Standards and the Science Core Curriculum Content Standards in Physics and Astronomy. The products include a 70-page teacher guide and an integrated CD-ROM with video clips, internet links, image sets used in the activities, and worksheets. The activities were presented at a series of teacher workshops. The teachers performed the activities themselves, learned additional background information on the Sun, solar magnetism, and the Sun-Earth connection, and were trained to use several items of equipment, which were made available in two "resource centers," one at NJIT and one at NJACE. In all, 81 teachers have been exposed to some or all of the activities. After the training, the teachers took the activities back to their classrooms, and 15 equipment to use with their students. Some teachers had access to, or had their schools purchase, Sunspotters and spectrometers rather than borrow the equipment. The success of the teacher training was assessed by questionnaires at the end of the workshops, by evaluation forms that the teachers filled out on returning the borrowed equipment.

  13. Observational Study of Solar Magnetic Active Phenomena Hongqi ...

    Indian Academy of Sciences (India)

    1991-06-09

    Jun 9, 1991 ... Key words. Sun: activity—flares—magnetic fields. 1. Introduction. It is believed that the newly emerging magnetic flux of opposite polarities and the shear of transverse magnetic field ... magnetic poles of negative polarity increased faster than positive one in active region. NOAA 6580-6619-6659. The total ...

  14. Effect of solar and magnetic activity on VHF scintillations near the equatorial anomaly crest

    Directory of Open Access Journals (Sweden)

    R. P. Singh

    2004-09-01

    Full Text Available The VHF amplitude scintillation recorded during the period January 1991 to December 1993 in the declining phase of a solar cycle and April 1998 to December 1999 in the ascending phase of the next solar cycle at Varanasi (geogr. lat.=25.3°, long.=83.0°, dip=37°N have been analyzed to study the behavior of ionospheric irregularities during active solar periods and magnetic storms. It is shown that irregularities occur at arbitrary times and may last for <30min. A rise in solar activity increases scintillations during winter (November-February and near equinoxes (March-April; September-October, whereas it depresses the scintillations during the summer (May-July. In general, the role of magnetic activity is to suppress scintillations in the pre-midnight period and to increase it in the post-midnight period during equinox and winter seasons, whilst during summer months the effect is reversed. The pre-midnight scintillation is sometimes observed when the main phase of Dst corresponds to the pre-midnight period. The annual variation shows suppression of scintillations on disturbed days, both during pre-midnight and post-midnight period, which becomes more effective during years of high solar activity. It is observed that for magnetic storms for which the recovery phase starts post-midnight, the probability of occurrence of irregularities is enhanced during this time. If the magnetic storm occurred during daytime, then the probability of occurrence of scintillations during the night hours is decreased. The penetration of magnetospheric electric fields to the magnetic equator affects the evolution of low-latitude irregularities. A delayed disturbance dynamo electric field also affects the development of irregularities.

  15. Solar Indices - Solar Radio Flux

    Data.gov (United States)

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

  16. Geometry of the solar wind transition region during the 11-year solar cycle

    International Nuclear Information System (INIS)

    Lotova, N.A.; Blums, D.F.

    1986-01-01

    Geometry of the solar wind transition region and its dynamics during the 11-year solar cycle is investigated. It is shown that the space geometry of the transition region suffers considerable changes. In the years of minimum of solar activity (1975-1977) the transition region has a form close to elliptical, shifts nearer to the Sun, while its width decreases. During the years of maximum of Solar activity (1979-1981) the form of the transition region becomes close to spherically symmetric, is located further from the Sun and its width is increased

  17. The turbulent cascade and proton heating in the solar wind during solar minimum

    International Nuclear Information System (INIS)

    Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A.

    2013-01-01

    Solar wind measurements at 1 AU during the recent solar minimum and previous studies of solar maximum provide an opportunity to study the effects of the changing solar cycle on in situ heating. Our interest is to compare the levels of activity associated with turbulence and proton heating. Large-scale shears in the flow caused by transient activity are a source that drives turbulence that heats the solar wind, but as the solar cycle progresses the dynamics that drive the turbulence and heat the medium are likely to change. The application of third-moment theory to Advanced Composition Explorer (ACE) data gives the turbulent energy cascade rate which is not seen to vary with the solar cycle. Likewise, an empirical heating rate shows no significan changes in proton heating over the cycle.

  18. Liposomal solubilization of new 3-hydroxy-quinolinone derivatives with promising anticancer activity: a screening method to identify maximum incorporation capacity

    DEFF Research Database (Denmark)

    Di Cagno, Massimiliano; Styskala, Jakub; Hlaváč, Jan

    2011-01-01

    Four new 3-hydroxy-quinolinone derivatives with promising anticancer activity could be solubilized using liposomes as vehicle to an extent that allows their in vitro and in vivo testing without use of toxic solvent(s). A screening method to identify the maximum incorporation capacity of hydrophobic......, resulting in a 200-500-fold increase in apparent solubility. Drug-to-lipid ratios in the range of 2-5 µg/mg were obtained. Interestingly, the four quinolinone derivatives have shown different association tendencies with liposomes, probably due to the physicochemical properties of the different group bonded...

  19. Solar rotation and activity in the past and their possible influence upon the evolution of life

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, E H

    1980-01-01

    Observations of enhanced spot active main sequence stars of solar type led to the formulation of the hypothesis which states that the rotational angular momentum, J/sub r/, of stars with spectral types later than F5 determines the intensity of their magnetic activity, bar A. Such very spot active stars are exclusively found as the components of fairly close binary stars, and show rotation periods smaller or more or less synchronous to the orbital period. Single stars of the lower main sequence are generally slow rotators, and do not show detectable activity in optical spectral regions, similar to the Sun if observed from stellar distances.

  20. Diagnostics of Coronal Heating in Solar Active Regions

    Science.gov (United States)

    Fludra, Andrzej; Hornsey, Christopher; Nakariakov, Valery

    2015-04-01

    We aim to develop a diagnostic method for the coronal heating mechanism in active region loops. Observational constraints on coronal heating models have been sought using measurements in the X-ray and EUV wavelengths. Statistical analysis, using EUV emission from many active regions, was done by Fludra and Ireland (2008) who studied power-law relationships between active region integrated magnetic flux and emission line intensities. A subsequent study by Fludra and Warren (2010) for the first time compared fully resolved images in an EUV spectral line of OV 63.0 nm with the photospheric magnetic field, leading to the identification of a dominant, ubiquitous variable component of the transition region EUV emission and a discovery of a steady basal heating, and deriving the dependence of the basal heating rate on the photospheric magnetic flux density. In this study, we compare models of single coronal loops with EUV observations. We assess to what degree observations of individual coronal loops made in the EUV range are capable of providing constraints on the heating mechanism. We model the coronal magnetic field in an active region using an NLFF extrapolation code applied to a photospheric vector magnetogram from SDO/HMI and select several loops that match an SDO/AIA 171 image of the same active region. We then model the plasma in these loops using a 1D hydrostatic code capable of applying an arbitrary heating rate as a function of magnetic field strength along the loop. From the plasma parameters derived from this model, we calculate the EUV emission along the loop in AIA 171 and 335 bands, and in pure spectral lines of Fe IX 17.1 nm and Fe XVI 33.5 nm. We use different spatial distributions of the heating function: concentrated near the loop top, uniform and concentrated near the footpoints, and investigate their effect on the modelled EUV intensities. We find a diagnostics based on the dependence of the total loop intensity on the shape of the heating function

  1. Solar activity - biosphere is the first great interdisciplinary problem in the history of the science

    International Nuclear Information System (INIS)

    Vladimirskij, B.M.

    1995-01-01

    The paper presents a historical review of the evolution of research in space effects on earth processes and phenomena. A discovery of 11-year cycling in the historical process related to the cycle of solar activity which discovery triggered the development of heliobiology, is noted. In the 1970 attention was paid to a potential ecological significance of variations of geomagnetic field, atmospheric intra sound, atmospheric radioactive radon concentration, though the basic active ecological parameter was considered to be electromagnetic disturbances in the range of low and super low frequencies. A relationship was recently established between the parameters of macroscopic fluctuations with variations of solar activity. A similarity of the spectrum of biological organism periods and the spectrum of space periods is also ascertained. 37 refs

  2. FINE MAGNETIC FEATURES AND CHIRALITY IN SOLAR ACTIVE REGION NOAA 10930

    International Nuclear Information System (INIS)

    Zhang Hongqi

    2010-01-01

    In this paper, we present fine magnetic features near the magnetic inversion line in the solar active region NOAA 10930. The high-resolution vector magnetograms obtained by Hinode allow detailed analyses around magnetic fibrils in the active region. The analyses are based on the fact that the electric current density can be divided into two components: the shear component caused by the magnetic inhomogeneity and the twist component caused by the magnetic field twist. The relationships between magnetic field, electric current density, and its two components are examined. It is found that the individual magnetic fibrils are dominated by the current density component caused by the magnetic inhomogeneity, while the large-scale magnetic region is generally dominated by the electric current component associated with the magnetic twist. The microstructure of the magnetic field in the solar atmosphere is far from the force-free field. The current mainly flows around the magnetic flux fibrils in the active regions.

  3. Market development for active solar thermal systems (ASTS) in the institutional, commercial and industrial (ICI) sectors

    International Nuclear Information System (INIS)

    2000-01-01

    The market potential for active solar thermal systems in the institutional, commercial and industrial sectors of the Canadian economy was investigated, the objective being to identify markets and to prepare action plans as the foundation for developing these markets by Natural Resources Canada and the industry. In the process of researching the market, barriers to market development in these sectors of the economy were also identified as well as actions to overcome these barriers. Nine potential applications were modelled to determine their energy, economic and environmental performance. Of these four attractive applications have been selected for more detailed treatment. Separate action plans have been developed for Natural Resources Canada, the Canadian Solar Industries Association and the active solar thermal industry. The close cooperation of all three partners is considered essential for a successful marketing effort. A marketing plan which gives due consideration to the product, planning, packaging, price and promotion, is also considered to be a vital ingredient, as is a meticulous follow-up on 'leads' created by exposure to the target market. Solarwall'TM' for preheating of ventilation air to new school buildings and solar domestic hot water heating for camp grounds have been identified as the most attractive candidates for marketing at this time. Highlights of marketing plans for these two options are included for purposes of illustrating the essential ingredients of marketing plans. 1 fig

  4. Long-term north-south asymmetry in solar wind speed inferred from geomagnetic activity: A new type of century-scale solar oscillation?

    DEFF Research Database (Denmark)

    Mursula, K.; Zieger, B.

    2001-01-01

    A significant and very similar annual variation in solar wind speed and in geomagnetic activity was recently found around all the four solar cycle minima covered by direct SW observations since mid-1960's. We have shown that the phase of this annual variation reverses with the Sun's polarity...... reversal, depicting a new form of 22-year periodicity. The annual variation results from a small north-south asymmetry in SW speed distribution where the minimum speed region is shifted toward the northern magnetic hemisphere. Here we study the very long-term evolution of the annual variation using early...... registrations of geomagnetic activity. We find a significant annual variation during the high-activity solar cycles in mid-19th century and since 1930's. Most interestingly, the SW speed asymmetry in mid-19th century was opposite to the present asymmetry, i.e., the minimum speed region was then shifted toward...

  5. Solar cycle effect on geomagnetic storms caused by interplanetary magnetic clouds

    Directory of Open Access Journals (Sweden)

    C.-C. Wu

    2006-12-01

    Full Text Available We investigated geomagnetic activity which was induced by interplanetary magnetic clouds during the past four solar cycles, 1965–1998. We have found that the intensity of such geomagnetic storms is more severe in solar maximum than in solar minimum. In addition, we affirm that the average solar wind speed of magnetic clouds is faster in solar maximum than in solar minimum. In this study, we find that solar activity level plays a major role on the intensity of geomagnetic storms. In particular, some new statistical results are found and listed as follows. (1 The intensity of a geomagnetic storm in a solar active period is stronger than in a solar quiet period. (2 The magnitude of negative Bzmin is larger in a solar active period than in a quiet period. (3 Solar wind speed in an active period is faster than in a quiet period. (4 VBsmax in an active period is much larger than in a quiet period. (5 Solar wind parameters, Bzmin, Vmax and VBsmax are correlated well with geomagnetic storm intensity, Dstmin during a solar active period. (6 Solar wind parameters, Bzmin, and VBsmax are not correlated well (very poorly for Vmax with geomagnetic storm intensity during a solar quiet period. (7 The speed of the solar wind plays a key role in the correlation of solar wind parameters vs. the intensity of a geomagnetic storm. (8 More severe storms with Dstmin≤−100 nT caused by MCs occurred in the solar active period than in the solar quiet period.

  6. Performance comparison between ethanol phase-change immersion and active water cooling for solar cells in high concentrating photovoltaic system

    International Nuclear Information System (INIS)

    Wang, Yiping; Wen, Chen; Huang, Qunwu; Kang, Xue; Chen, Miao; Wang, Huilin

    2017-01-01

    Highlights: • Thermal performances of ethanol phase-change immersion and active water cooling are compared. • Effects of operation parameters on ethanol phase-change immersion are studied. • Optimum filling ratio is 30% for ethanol phase-change immersion cooling system. • Exergy efficiency of ethanol phase-change immersion method increases by 57%. - Abstract: This paper presents an optimized ethanol phase-change immersion cooling method to obtain lower temperature of dense-array solar cells in high concentrating photovoltaic system. The thermal performances of this system were compared with a conventional active water cooling system with minichannels from the perspectives of start-up characteristic, temperature uniformity, thermal resistance and heat transfer coefficient. This paper also explored the influences of liquid filling ratio, absolute pressure and water flow rate on thermal performances. Dense-array LEDs were used to simulate heat power of solar cells worked under high concentration ratios. It can be observed that the optimal filling ratio was 30% in which the thermal resistance was 0.479 °C/W and the heat transfer coefficient was 9726.21 W/(m 2 ·°C). To quantify the quality of energy output of two cooling systems, exergy analysis are conducted and maximum exergy efficiencies were 17.70% and 11.27%, respectively. The experimental results represent an improvement towards thermal performances of ethanol phase-change immersion cooling system due to the reduction in contact thermal resistance. This study improves the operation control and applications for ethanol phase-change immersion cooling technology.

  7. Solar Energy and You.

    Science.gov (United States)

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    This booklet provides an introduction to solar energy by discussing: (1) how a home is heated; (2) how solar energy can help in the heating process; (3) the characteristics of passive solar houses; (4) the characteristics of active solar houses; (5) how solar heat is stored; and (6) other uses of solar energy. Also provided are 10 questions to…

  8. Evidence for the impact of stellar activity on the detectability of solar-like oscillations observed by Kepler

    NARCIS (Netherlands)

    Chaplin, W.J.; Bedding, T.R.; Bonanno, A.; Broomhall, A.M.; Garcia, R.A.; Hekker, S.; Huber, D.; Verner, G.A.; Basu, S.; Elsworth, Y.; Houdek, G.; Mathur, S.; Mosser, B.; New, R.; Stevens, I.R.; Appourchaux, T.; Karoff, C.; Metcalfe, T.S.; Molenda-Zakowicz, J.; Monteiro, M.J.P.F.G.; Thompson, M.J.; Christensen-Dalsgaard, J.; Gilliland, R.L.; Kawaler, S.D.; Kjeldsen, H.; Ballot, J.; Benomar, O.; Corsaro, E.; Campante, T.L.; Gaulme, P.; Hale, S.J.; Handberg, R.; Jarvis, E.; Regulo, C.; Roxburgh, I.W.; Salabert, D.; Stello, D.; Mullally, F.; Li, J.; Wohler, W.

    2011-01-01

    We use photometric observations of solar-type stars, made by the NASA Kepler Mission, to conduct a statistical study of the impact of stellar surface activity on the detectability of solar-like oscillations. We find that the number of stars with detected oscillations falls significantly with

  9. Alfvénic fluctuations in "newborn"' polar solar wind

    Directory of Open Access Journals (Sweden)

    B. Bavassano

    2005-06-01

    Full Text Available The 3-D structure of the solar wind is strongly dependent upon the Sun's activity cycle. At low solar activity a bimodal structure is dominant, with a fast and uniform flow at the high latitudes, and slow and variable flows at low latitudes. Around solar maximum, in sharp contrast, variable flows are observed at all latitudes. This last kind of pattern, however, is a relatively short-lived feature, and quite soon after solar maximum the polar wind tends to regain its role. The plasma parameter distributions for these newborn polar flows appear very similar to those typically observed in polar wind at low solar activity. The point addressed here is about polar wind fluctuations. As is well known, the low-solar-activity polar wind is characterized by a strong flow of Alfvénic fluctuations. Does this hold for the new polar flows too? An answer to this question is given here through a comparative statistical analysis on parameters such as total energy, cross helicity, and residual energy, that are of general use to describe the Alfvénic character of fluctuations. Our results indicate that the main features of the Alfvénic fluctuations observed in low-solar-activity polar wind have been quickly recovered in the new polar flows developed shortly after solar maximum. Keywords. Interplanetary physics (MHD waves and turbulence; Sources of the solar wind – Space plasma physics (Turbulence

  10. Solar cosmic rays in the system of solar terrestrial relations

    Science.gov (United States)

    Miroshnichenko, Leonty I.

    2008-02-01

    In this brief review, we discuss a number of geophysical effects of solar energetic particles (SEPs) or solar cosmic rays (SCR). We concentrate mainly on the observational evidence and proposed mechanisms of some expected effects and/or poor-studied phenomena discovered within the last three decades, in particular, depletion of the ozone layer, perturbations in the global electric current, effects on the winter storm vorticity, change of the atmospheric transparency and production of nitrates. Some "archaeological" data on SCR fluxes in the past and upper limit of total energy induced by SEPs are also discussed. Due attention is paid to the periodicities in the solar particle fluxes. Actually, many solar, heliospheric and terrestrial parameters changing generally in phase with the solar activity are subjected to a temporary depression close to the solar maximum ("Gnevyshev Gap"). A similar gap has been found recently in the yearly numbers of the >10 MeV proton events. All the above-mentioned findings are evidently of great importance in the studies of general proton emissivity of the Sun and long-term trends in the behaviour of solar magnetic fields. In addition, these data can be very helpful for elaborating the methods for prediction of the radiation conditions in space and for estimation of the SEPs' contribution to solar effects on the geosphere, their relative role in the formation of terrestrial weather and climate and in the problem of solar-terrestrial relations (STR) on the whole.

  11. Dependence of regular background noise of VLF radiation and thunder-storm activity on solar wind proton density

    International Nuclear Information System (INIS)

    Sobolev, A.V.; Kozlov, V.I.

    1997-01-01

    Correlation of the intensity of slowly changing regular background noise within 9.7 kHz frequency in Yakutsk (L = 3) and of the solar wind density protons was determined. This result explains the reverse dependence of the intensity of the regular background noise on the solar activity, 27-day frequency, increase before and following geomagnetic storms, absence of relation with K p index of geomagnetic activity. Conclusion is made that growth of density of the solar wind protons results in increase of the regular background noise and thunderstorm activity

  12. Search for outlying data points in multivariate solar activity data sets

    International Nuclear Information System (INIS)

    Bartkowiak, A.; Jakimiec, M.

    1989-01-01

    The aim of this paper is the investigation of outlying data points in the solar activity data sets. Two statistical methods for identifying of multivariate outliers are presented: the chi2-plot method based on the analysis of Mahalanobis distances and the method based on principal component analysis, i.e. on scatterdiagrams constructed from the first two or last two eigenvectors. We demonstrate the usefullness of these methods applying them to same data of solar activity. The methods allow to reveal quite precisely the data vectors containing some errors and also some untypical vectors, i.e. vectors with unusually large values or with values revealing untypical relations as compared with the common relations between the appropriate variables. 12 refs., 7 figs., 8 tabs. (author)

  13. July 1974 solar events: a possible lower limit for microwave activity

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, P; Iacomo, P Jr; Koppe, E H; Marques dos Santos, P; Schaal, R E [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica; Blakey, J R [Surrey Univ., Guildford (UK). Dept. of Physics

    1975-11-01

    The active region McMath 10433 was the source of several flares and radio outbursts during the early part of July 1974. This region was tracked continuously, for several periods during the month at 22.2 GHz using a telescope with a 4 minutes of arc beam. Comparison with the results obtained simultaneously with a normal 7 GHz solar instrument indicate that there is important burst activity occurring at levels below the detection limit of normal solar patrol instruments. The time-development morphology of these bursts is similar to those normally observed and has enabled the simple events to be re-interpreted. A completely new type of event-the fast absorption-has also been recognized. The correlation of the microwave events with SPA events observed on VLF propagation is also discussed.

  14. Differential rotation of the Sun and the Maunder minimum of solar activity

    International Nuclear Information System (INIS)

    Ikhsanov, R.N.; Vitinskij, Yu.I.

    1980-01-01

    Nature of differential rotation of the Sun is discussed. Investigation of long term changes in differential rotation separately for two phase of 11 year cycle of the Sun activity is carried out. Data on heliographic coordinates for every day of all groups of the Sun spots for the years preceding the epoch of the minimum of the 11 year cycle and the Sun groups for the years of maximum from ''Greenwich Photoheliographic Results'' for 1875-1954 are used as initial material. It is shown that differential rotation of the Sun changes in time from one 11 year cycle of the Sun activity to another. This change is connected with the power of 11 year cycle. During the maximum phase of 11 year cycle differentiality of the rotation increases in the cycles where the cycle maximum is higher. Before the minimum of 11 year cycle rotation differentiability is lower in the cycles for which activity maximum is higher in the next 11 year cycle. Equatorial rate of the Sun rotation increases with the decrease in the cycle power when the maximum Wolf number is less than 110. The mentioned regularities took place both during Maunder minimum and before its beginning [ru

  15. Maximum oxygen uptake and objectively measured physical activity in Danish children 6-7 years of age: the Copenhagen school child intervention study

    DEFF Research Database (Denmark)

    Eiberg, Stig; Hasselstrøm, Henriette; Grønfeldt, Vivian

    2005-01-01

    Objectives: To provide normative data on maximum oxygen uptake (V·O2MAX) and physical activity in children 6-7 years of age and analyse the association between these variables. Methods: VO2MAX was measured in 366 boys (mean (SD) 6.8 (0.4) years of age) and 332 girls (6.7 (0.4) years of age) from.......5 (6.0) v 44.8 (5.6) ml/kg/min (+8%); pgirls. The difference in VO2MAX between boys and girls decreased to +2% when expressed relative to lean body mass (LBM). Absolute VO2MAX was related to LBM, body mass, and stature (all pBoys were more physically active than girls (mean counts...... +9.4%, pboys and girls with the same VO2MAX were compared, boys were more active. The difference in physical activity between the sexes was higher when sustained activity of higher intensity was compared. Conclusions: VO2MAX is higher in boys than girls (+11%), even when...

  16. Forecast daily indices of solar activity, F10.7, using support vector regression method

    International Nuclear Information System (INIS)

    Huang Cong; Liu Dandan; Wang Jingsong

    2009-01-01

    The 10.7 cm solar radio flux (F10.7), the value of the solar radio emission flux density at a wavelength of 10.7 cm, is a useful index of solar activity as a proxy for solar extreme ultraviolet radiation. It is meaningful and important to predict F10.7 values accurately for both long-term (months-years) and short-term (days) forecasting, which are often used as inputs in space weather models. This study applies a novel neural network technique, support vector regression (SVR), to forecasting daily values of F10.7. The aim of this study is to examine the feasibility of SVR in short-term F10.7 forecasting. The approach, based on SVR, reduces the dimension of feature space in the training process by using a kernel-based learning algorithm. Thus, the complexity of the calculation becomes lower and a small amount of training data will be sufficient. The time series of F10.7 from 2002 to 2006 are employed as the data sets. The performance of the approach is estimated by calculating the norm mean square error and mean absolute percentage error. It is shown that our approach can perform well by using fewer training data points than the traditional neural network. (research paper)

  17. Design of Solar Harvested Semi Active RFID Transponder with Supercapacitor Storage

    OpenAIRE

    Gary Valentine; Lukas Vojtech; Marek Neruda

    2015-01-01

    This paper presents the analysis, design and manufacture of a low cost, low maintenance and long-range prototype of RFID transponder with continuous operability. A prototype of semi-active RFID transponder is produced with a range that can be extended via a DC input to allow all of the readers signal power to be reflected via backscatter modulation. The transponder is powered via solar harvested power which is selected over other energy harvesting technologies as it provides a greater energy ...

  18. Evidence for extreme divergence of open field lines from solar activity

    International Nuclear Information System (INIS)

    Dulk, G.A.; Suzuki, S.; Melrose, D.B.

    1979-01-01

    This paper reviews the evidence on the structure of the open magnetic field lines that emerge from solar active regions into interplanetary space. The evidence comes mainly from the measured sizes, positions and polarization of Type III and Type V bursts, and from electron streams observed from space. It is found that the observations are best interpreted in terms of a strongly-diverging field topology, with the open field lines filling a cone of angle approx. 60 0

  19. Towards better description of solar activity variation in the International Reference Ionosphere topside ion composition model

    Czech Academy of Sciences Publication Activity Database

    Truhlík, Vladimír; Bilitza, D.; Třísková, Ludmila

    2015-01-01

    Roč. 55, č. 8 (2015), s. 2099-2105 ISSN 0273-1177 R&D Projects: GA MŠk(CZ) LH11123 Institutional support: RVO:68378289 Keywords : ion composition * topside ionosphere * solar activity * empirical model * International Reference Ionosphere Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.409, year: 2015 http://www.sciencedirect.com/science/article/pii/S027311771400489X

  20. Latitudinal variation of the topside electron temperature at different levels of solar activity

    Czech Academy of Sciences Publication Activity Database

    Truhlík, Vladimír; Bilitza, D.; Třísková, Ludmila

    2009-01-01

    Roč. 44, č. 6 (2009), s. 693-700 ISSN 0273-1177 R&D Projects: GA AV ČR IAA300420603 Grant - others: NASA (US) NNH06CD17C Institutional research plan: CEZ:AV0Z30420517 Keywords : Electron temperature * Solar activity variation * Latitudinal dependence Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.079, year: 2009

  1. Solar Flare Aimed at Earth

    Science.gov (United States)

    2002-01-01

    At the height of the solar cycle, the Sun is finally displaying some fireworks. This image from the Solar and Heliospheric Observatory (SOHO) shows a large solar flare from June 6, 2000 at 1424 Universal Time (10:24 AM Eastern Daylight Savings Time). Associated with the flare was a coronal mass ejection that sent a wave of fast moving charged particles straight towards Earth. (The image was acquired by the Extreme ultaviolet Imaging Telescope (EIT), one of 12 instruments aboard SOHO) Solar activity affects the Earth in several ways. The particles generated by flares can disrupt satellite communications and interfere with power transmission on the Earth's surface. Earth's climate is tied to the total energy emitted by the sun, cooling when the sun radiates less energy and warming when solar output increases. Solar radiation also produces ozone in the stratosphere, so total ozone levels tend to increase during the solar maximum. For more information about these solar flares and the SOHO mission, see NASA Science News or the SOHO home page. For more about the links between the sun and climate change, see Sunspots and the Solar Max. Image courtesy SOHO Extreme ultaviolet Imaging Telescope, ESA/NASA

  2. Essential features of long-term changes of areas and diameters of sunspot groups in solar activity cycles 12-24

    Science.gov (United States)

    Efimenko, V. M.; Lozitsky, V. G.

    2018-06-01

    We analyze the Greenwich catalog data on areas of sunspot groups of last thirteen solar cycles. Various parameters of sunspots are considered, namely: average monthly smoothed areas, maximum area for each year and equivalent diameters of groups of sunspots. The first parameter shows an exceptional power of the 19th cycle of solar activity, which appears here more contrastively than in the numbers of spots (that is, in Wolf's numbers). It was found that in the maximum areas of sunspot groups for a year there is a unique phenomenon: a short and high jump in the 18th cycle (in 1946-1947) that has no analogues in other cycles. We also studied the integral distributions for equivalent diameters and found the following: (a) the average value of the index of power-law approximation is 5.4 for the last 13 cycles and (b) there is reliable evidence of Hale's double cycle (about 44 years). Since this indicator reflects the dispersion of sunspot group diameters, the results obtained show that the convective zone of the Sun generates embryos of active regions in different statistical regimes which change with a cycle of about 44 years.

  3. The investigation of solar activity signals by analyzing of tree ring chronological scales

    Science.gov (United States)

    Nickiforov, M. G.

    2017-07-01

    The present study examines the ability of detecting short-cycles and global minima of solar activity by analyzing dendrochronologies. Starting with the study of Douglass, which was devoted to the question of climatic cycles and the growth of trees, it is believed that the analysis of dendrochronologies allows to detect the cycle of Wolf-Schwabe. According to his results, the cycle was absent during Maunder's minimum and appeared after its completion. Having checked Douglass's conclusions by using 10 dendrochronologies of yellow pines from Arizona, which cover the time period from 1600 to 1900, we have come to the opposite results. The verification shows that: a) none of the considered dendroscale allows to detect an 11-year cycle; 2) the behaviour of a short peroid-signal does not undergo significant changes before, during or after Maunder's minimum. A similar attempt to detect global minima of solar activity by using five dendrochronologies from different areas has not led to positive results. On the one hand, the signal of global extremum is not always recorded in dendrochronology, on the other hand, the deep depression of annual rings allows to suppose the existence of a global minimum of solar activity, which is actually absent.

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

    Directory of Open Access Journals (Sweden)

    Ducić Vladan

    2008-01-01

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

  5. MAGNETIC FLUX TRANSPORT AND THE LONG-TERM EVOLUTION OF SOLAR ACTIVE REGIONS

    International Nuclear Information System (INIS)

    Ugarte-Urra, Ignacio; Upton, Lisa; Warren, Harry P.; Hathaway, David H.

    2015-01-01

    With multiple vantage points around the Sun, Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory imaging observations provide a unique opportunity to view the solar surface continuously. We use He ii 304 Å data from these observatories to isolate and track ten active regions and study their long-term evolution. We find that active regions typically follow a standard pattern of emergence over several days followed by a slower decay that is proportional in time to the peak intensity in the region. Since STEREO does not make direct observations of the magnetic field, we employ a flux-luminosity relationship to infer the total unsigned magnetic flux evolution. To investigate this magnetic flux decay over several rotations we use a surface flux transport model, the Advective Flux Transport model, that simulates convective flows using a time-varying velocity field and find that the model provides realistic predictions when information about the active region's magnetic field strength and distribution at peak flux is available. Finally, we illustrate how 304 Å images can be used as a proxy for magnetic flux measurements when magnetic field data is not accessible

  6. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  7. SIMULATION OF NEW SIMPLE FUZZY LOGIC MAXIMUM POWER ...

    African Journals Online (AJOL)

    2010-06-30

    Jun 30, 2010 ... Basic structure photovoltaic system Solar array mathematic ... The equivalent circuit model of a solar cell consists of a current generator and a diode .... control of boost converter (tracker) such that maximum power is achieved at the output of the solar panel. Fig.11. The membership function of input. Fig.12.

  8. Possible biophysical mechanism of the effect of the solar activity on the human central nervous system

    Science.gov (United States)

    Mikhailova, G. A.; Mikhailov, Y. M.

    Numerous studies, beginning with Tchizhevsky's works, demonstrated the undeniable effect of the solar activity on the human body. A possible geophysical mechanism of the effect of the solar activity on the human body was proposed by Vladimirsky. In this mechanism solar disturbances (powerful chromospheres flares) cause "magnetosphere and plasmasphere disturbances on the Earth (sudden magnetic storms), which are accompanied by a change in the spectrum of the electromagnetic field on the Earth's surface in the extremely low frequency band. In its turn, this brings about shifts in the phisiological indices of the human body". In this model, the human body is regarded as a self-oscillating system affected by external geophysical factors. We also adhere to the main principles of this model but refine the part of this model that describes the change in the spectrum of the electromagnetic field on the Earth's surface in the extremely low frequency band. Unlike Vladimirsky model, we regard the human is not as a self-oscillating system but as one of two coupled oscillating system with discrete resonance frequencies in the human-habitat ensemble. Solar processes and their induced changes in one of the two coupled oscillating systems, specifically, the habitat play the role of an external force. Such an approach is based on the fact that the brain rhythms have the following definite frequencies: the alpha rhythm, 8-13 Hz; the beta rhythm, 14-30 Hz; the gamma rhythm, above 30 Hz; the delta rhythm, 1.5-3 Hz; and the theta rhythm, 4-7 Hz. On the other hand, the natural electromagnetic field on the Earth's surface in the extremely low frequency band also has a quite distinct resonance distribution. There are so-called Schuman resonances of the cavity formed by the Earth's surface and the lower boundary of the ionosphere (the D and E layers) at f1=10.6; f2=18.3; f3=25.9; f4=33.5; f5=41.1 Hz. These resonance frequencies are variable and most sensitive to variations of the

  9. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  10. The Relation Between Magnetic Fields and X-ray Emission for Solar Microflares and Active Regions

    Science.gov (United States)

    Kirichenko, A. S.; Bogachev, S. A.

    2017-09-01

    We present the result of a comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we used the monochromatic MgXII Imaging Spectroheliometer (MISH), the Full-disk EUV Telescope (FET), and the Solar PHotometer in X-rays (SphinX) instruments onboard the Complex Orbital Observations Near-Earth of Activity of the Sun-Photon CORONAS- Photon spacecraft because of their high sensitivity in soft X-rays. The peak flare flux (PFF) for solar microflares was found to depend on the strength of the magnetic field and on the total unsigned magnetic flux as a power-law function. In the spectral range 2.8 - 36.6 Å, which shows very little increase related to microflares, the power-law index of the relation between the X-ray flux and magnetic flux for active regions is 1.48 ±0.86, which is close to the value obtained previously by Pevtsov et al. ( Astrophys. J. 598, 1387, 2003) for different types of solar and stellar objects. In the spectral range 1 - 8 Å, the power-law indices for PFF(B) and PFF(Φ) for microflares are 3.87 ±2.16 and 3 ±1.6, respectively. We also make suggestions on the heating mechanisms in active regions and microflares under the assumption of loops with constant pressure and heating using the Rosner-Tucker-Vaiana scaling laws.

  11. Activity of processes on the visible surface of planets of Solar system

    Science.gov (United States)

    Vidmachenko, A. P.

    2016-05-01

    According to modern concepts bodies of the solar system formed from a single cloud of gas and dust. Calculations show that in the protoplanetary nebula where the temperature is lowered to 1600 K - appeared the first type of metal (aluminum and titanium) and metal oxides in the form of dust particles. With further decreasing temperature of the nebula to 1400 K - appeared also dust of iron and iron-nikel alloy; at 1300 K - appear solid silicates; magnesium minerals formed at T 1200 K. These components are material for the formation of basaltic rocks. At temperatures T 300 K begins to form water molecules. At 100-200 K in a remote part of the nebula - ammonia, methane and their ice are formed. In the outer part of Solar system this ices are now preserved in comet nuclei and in the icy satellites of giant planets. During T 400 million years after the formation of the Sun, at first - from dust component of the protoplanetary cloud was formed many intermediate bodies with the size of hundreds kilometers. Their gravitational interaction was reinforced in process of their grow. The bodies, which were growing fastest, they became the embryos of the future planets. All bodies of the solar system in different degrees show manifestations of different types of activity processes on the surface or at the level of the visible clouds. This activity depends on the distance of a particular body from the Sun, surface chemical composition, physical conditions at the surface and so on. The farther away from the Sun is the object, the temperature of its visible surface is lower, and by that more interesting is the set of processes, of chemical and physical transformations that there is possible to register. The surface of each planets of Solar system is very active in a variety of set temperature and chemical composition

  12. Solar Energy Education. Renewable energy activities for junior high/middle school science

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Some basic topics on the subject of solar energy are outlined in the form of a teaching manual. The manual is geared toward junior high or middle school science students. Topics include solar collectors, solar water heating, solar radiation, insulation, heat storage, and desalination. Instructions for the construction of apparatus to demonstrate the solar energy topics are provided. (BCS)

  13. ON THE NON-KOLMOGOROV NATURE OF FLARE-PRODUCTIVE SOLAR ACTIVE REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mandage, Revati S. [Physics and Astronomy Department, Rice University, 6100 Main MS-61, Houston, TX 77005-1827 (United States); McAteer, R. T. James, E-mail: mcateer@nmsu.edu [Department of Astronomy, New Mexico State University, MSC 4500, Las Cruces, NM 88001 (United States)

    2016-12-20

    A magnetic power spectral analysis is performed on 53 solar active regions, observed from 2011 August to 2012 July. Magnetic field data obtained from the Helioseismic and Magnetic Imager, inverted as Active Region Patches, are used to study the evolution of the magnetic power index as each region rotates across the solar disk. Active regions are classified based on the numbers and sizes of solar flares they produce in order to study the relationship between flare productivity and the magnetic power index. The choice of window size and inertial range plays a key role in determining the correct magnetic power index. The overall distribution of magnetic power indices has a range of 1.0–2.5. Flare-quiet regions peak at a value of 1.6. However, flare-productive regions peak at a value of 2.2. Overall, the histogram of the distribution of power indices of flare-productive active regions is well separated from flare-quiet active regions. Only 12% of flare-quiet regions exhibit an index greater than 2, whereas 90% of flare-productive regions exhibit an index greater than 2. Flare-quiet regions exhibit a high temporal variance (i.e., the index fluctuates between high and low values), whereas flare-productive regions maintain an index greater than 2 for several days. This shows the importance of including the temporal evolution of active regions in flare prediction studies, and highlights the potential of a 2–3 day prediction window for space weather applications.

  14. Effect of solar activity on the concentration of Be-7 in air and precipitation

    International Nuclear Information System (INIS)

    Hoetzl, H.; Rosner, G.; Winkler, R.

    1993-01-01

    The time course of the activity concentration of the cosmogenic Be-7, measured in surface air and deposition since 1971, reflects a cyclic pattern of two frequency components. The well-known seasonal period with maxima in early summer is superimposed by a long-term period of about 11 years, which is obviously related to the effect of solar activity. By means of time series analysis using Fast-Fourier-Transformation and crosscorrelation, respectively, this relationship could be confirmed on a statistical basis for a period of two sun spot cycles (1971-1992). (orig.) [de

  15. Polarization reversal during the solar noise storm activity of August 1971

    International Nuclear Information System (INIS)

    Kurihara, Masahiro

    1975-01-01

    Reversals of the sense of circular polarization of solar radio emission were observed for active type I storms in August 1971. Observations with a 160-MHz interferometer revealed that the reversals were caused by sudden growth and decay of a secondary storm source whose sense of polarization was opposite to that of the long-lasting main source. The time variations of both the associated S-component sources and sunspots are compared with that of the storm sources. The role of the magnetic field, which presumably connects the storm sources, the S-component sources, and the sunspots, is discussed in relation to the origin of the storm activity. (author)

  16. Long-term solar activity and terrestrial connections. Part II: at the beckon of the sun?

    Directory of Open Access Journals (Sweden)

    N. D. Diamantides

    1998-05-01

    Full Text Available The research task described herein aims at the structuring of an analytical tool that traces the time course of geophysical phenomena, regional or global, and compares it to the course of long-term solar conditions, long-term meaning decades or a few centuries. The model is based on the premise that since in a last analysis the preponderance of atmospheric, hydrospheric, and, possibly, some aspects of geospheric phenomena are, or have been, powered by energy issuing from the sun - either now or in the past - the long-term behavior of such phenomena is ultimately "connected" to long-term changes occurring in the sun itself. Accordingly, the proposed research firstly derives and models a stable surrogate pattern for the long-term solar activity, secondly introduces a transfer-function algorithm for modeling the connection between the surrogate and terrestrial phenomena viewed as partners in the connection, and thirdly probes the connection outcome for episodic or unanticipated effects that may arise due to the fact that in the present context, the connection, should it exist, is very likely nonlinear. Part I of the study presents the theory of the concept, while Part II demonstrates the concept's pertinence to a number of terrestrial phenomena.Key words. Solar activity · Kolmogorov algorithm

  17. Long-term solar activity and terrestrial connections. Part I: theory

    Directory of Open Access Journals (Sweden)

    N. D. Diamantides

    Full Text Available The research task described herein aims at the structuring of an analytical tool that traces the time course of geophysical phenomena, regional or global, and compares it to the course of long-term solar conditions, long-term meaning decades or a few centuries. The model is based on the premise that since in a last analysis the preponderance of atmospheric, hydrospheric, and, possibly, some aspects of geospheric phenomena are, or have been, powered by energy issuing from the sun – either now or in the past, the long-term behavior of such phenomena is ultimately "connected" to long-term changes occurring in the sun itself. Accordingly, the proposed research firstly derives and models a stable surrogate pattern for the long-term solar activity, secondly introduces a transfer-function algorithm for modeling the connection between the surrogate and terrestrial phenomena viewed as partners in the connection, and thirdly probes the connection outcome for episodic or unanticipated effects that may arise due to the fact that in the present context, the connection, should it exist, is very likely nonlinear. Part I of the study presents the theory of the concept, while Part II demonstrates the concept's pertinence to a number of terrestrial phenomena.

    Key words. Solar activity · Kolmogorov algorithm

  18. Long-term solar activity and terrestrial connections. Part II: at the beckon of the sun?

    Directory of Open Access Journals (Sweden)

    N. D. Diamantides

    Full Text Available The research task described herein aims at the structuring of an analytical tool that traces the time course of geophysical phenomena, regional or global, and compares it to the course of long-term solar conditions, long-term meaning decades or a few centuries. The model is based on the premise that since in a last analysis the preponderance of atmospheric, hydrospheric, and, possibly, some aspects of geospheric phenomena are, or have been, powered by energy issuing from the sun - either now or in the past - the long-term behavior of such phenomena is ultimately "connected" to long-term changes occurring in the sun itself. Accordingly, the proposed research firstly derives and models a stable surrogate pattern for the long-term solar activity, secondly introduces a transfer-function algorithm for modeling the connection between the surrogate and terrestrial phenomena viewed as partners in the connection, and thirdly probes the connection outcome for episodic or unanticipated effects that may arise due to the fact that in the present context, the connection, should it exist, is very likely nonlinear. Part I of the study presents the theory of the concept, while Part II demonstrates the concept's pertinence to a number of terrestrial phenomena.

    Key words. Solar activity · Kolmogorov algorithm

  19. Long-term solar activity and terrestrial connections. Part I: theory

    Directory of Open Access Journals (Sweden)

    N. D. Diamantides

    1998-05-01

    Full Text Available The research task described herein aims at the structuring of an analytical tool that traces the time course of geophysical phenomena, regional or global, and compares it to the course of long-term solar conditions, long-term meaning decades or a few centuries. The model is based on the premise that since in a last analysis the preponderance of atmospheric, hydrospheric, and, possibly, some aspects of geospheric phenomena are, or have been, powered by energy issuing from the sun – either now or in the past, the long-term behavior of such phenomena is ultimately "connected" to long-term changes occurring in the sun itself. Accordingly, the proposed research firstly derives and models a stable surrogate pattern for the long-term solar activity, secondly introduces a transfer-function algorithm for modeling the connection between the surrogate and terrestrial phenomena viewed as partners in the connection, and thirdly probes the connection outcome for episodic or unanticipated effects that may arise due to the fact that in the present context, the connection, should it exist, is very likely nonlinear. Part I of the study presents the theory of the concept, while Part II demonstrates the concept's pertinence to a number of terrestrial phenomena.Key words. Solar activity · Kolmogorov algorithm

  20. Combined Active and Passive Solar Space Heating and Solar Hot Water Systems for an Elementary School in Boise, Idaho.

    Science.gov (United States)

    Smull, Neil A.; Armstrong, Gerald L.

    1979-01-01

    Amity Elementary School in Boise, Idaho, features a solar space heating and domestic hot water system along with an earth covering to accommodate the passive aspects of energy conservation. (Author/MLF)

  1. Towards understanding the nature of any relationship between Solar Activity and Cosmic Rays with thunderstorm activity and lightning discharge

    Science.gov (United States)

    O'Regan, J.; Muller, J.-P.; Matthews, S.

    2012-04-01

    The runaway breakdown hypothesis of lightning discharge has predicted relationships between cosmic rays' interactions with the atmosphere and thunderstorm production and lightning activity. Precipitating energetic particles lead to the injection of MeV-energy electrons into electrified thunderclouds [1,2], resulting in runaway breakdown occurring, and assisting in the process of charge separation [2]. Previous lightning studies show that correlations to solar activity are weak but significant, with better correlations to solar activity and cosmic rays when carried out over smaller geographical areas [3,4,5,6] and over longer timescales [6]. In this work, correlations are explored between variations of SEPs and lightning activity levels at various spatio-temporal scales. Temporal scales span from short-term (days) scales surrounding large Earth-directed coronal mass ejection (CME) events to long-term (years) scales. Similarly, spatial scales span from 1-degree x 1-degree latitudinal-longitudinal grid scales to an entirely global study, for varying timescales. Additionally, investigation of correlation sign and statistical significance by 1-degree latitudinal bands is also employed, allowing a comparative study of lightning activity relative to regions of greatest - and contrasting regions of relative absence of - energetic particle precipitation. These regions are determined from electron and proton flux maps, derived from measurements from the Medium Energy Proton and Electron Detector (MEPED) onboard the Polar Orbiting Environmental Satellite (POES) system. Lightning data is obtained from the World Wide Lightning Location Network (WWLLN) for the period 2005 to 2011. The correlations of lightning strike rates are carried out with respect to Relative Sunspot Number (R), 10.7cm Solar radio flux (F10.7), Galactic Cosmic Ray (GCR) neutron monitor flux, the Ap geomagnetic activity index, and Disturbance Storm Time (DST) index. Correlations show dramatic variations in

  2. Climatology of GNPs ionospheric scintillation at high and mid latitudes under different solar activity conditions

    International Nuclear Information System (INIS)

    Spogli, L.; Alfonsi, L.; De Franceschi, G.; Romano, V.; Aquino, M.H.O.; Dodson, A.

    2010-01-01

    We analyze data of ionospheric scintillation over North European regions for the same period (October to November) of two different years (2003 and 2008), characterized by different geomagnetic conditions. The work aims to develop a scintillation climatology of the high- and mid-latitude ionosphere, analyzing the behaviour of the scintillation occurrence as a function of the magnetic local time (MLT) and of the altitude adjusted corrected magnetic latitude (M lat), to characterize scintillation scenarios under different solar activity conditions. The results shown herein are obtained merging observations from a network of GISTMs (GPS Ionospheric Scintillation and TEC Monitor) located over a wide range of latitudes in the northern hemisphere. Our findings confirm the associations of the occurrence of the ionospheric irregularities with the expected position of the auroral oval and of the ionospheric trough walls and show the contribution of the polar cap patches even under solar minimum conditions.

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

    Science.gov (United States)

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

    2016-12-01

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

  4. Solar Light Responsive Photocatalytic Activity of Reduced Graphene Oxide-Zinc Selenide Nanocomposite

    Science.gov (United States)

    Chakraborty, Koushik; Ibrahim, Sk; Das, Poulomi; Ghosh, Surajit; Pal, Tanusri

    2017-10-01

    Solution processable reduced graphene oxide-zinc selenide (RGO-ZnSe) nanocomposite has been successfully synthesized by an easy one-pot single-step solvothermal reaction. The RGO-ZnSe composite was characterized structurally and morphologically by the study of XRD analysis, SEM and TEM imaging. Reduction in graphene oxide was confirmed by FTIR spectroscopy analysis. Photocatalytic efficiency of RGO-ZnSe composite was investigated toward the degradation of Rhodamine B under solar light irradiation. Our study indicates that the RGO-ZnSe composite is catalytically more active compared to the controlled-ZnSe under the solar light illumination. Here, RGO plays an important role for photoinduced charge separation and subsequently hinders the electron-hole recombination probability that consequently enhances photocatalytic degradation efficiency. We expect that this type of RGO-based optoelectronics materials opens up a new avenue in the field of photocatalytic degradation of different organic water pollutants.

  5. Properties and Photocatalytic Activity of β-Ga2O3 Nanorods under Simulated Solar Irradiation

    Directory of Open Access Journals (Sweden)

    Yinzhen Wang

    2015-01-01

    Full Text Available β-Ga2O3 nanorods are prepared by hydrothermal method and characterized by X-ray diffraction, high-resolution transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectra. The results reveal that high crystallinity, monoclinic phase of β-Ga2O3 nanorods were prepared with a diameter of about 60 nm and length of 500 nm. Photoluminescence study indicates that the β-Ga2O3 nanorods exhibit a broad blue light emission at room temperature. The β-Ga2O3 nanorods displayed high photocatalytic activity under simulated solar irradiation; after 2 h irradiation, over 95% of methylene blue solution and over 90% of methyl orange solution were decolorized. Since this process does not require additional hydrogen peroxide and uses solar light, it can be developed as an economically feasible and environmentally friendly method to treat dye effluent.

  6. On the Reconstruction of the Convection Pattern Below an Active Region of Solar Corona

    International Nuclear Information System (INIS)

    Pirot, Dorian; Gaudet, Jonathan; Vincent, Alain

    2012-01-01

    In order to better understand magneto-convective patterns and flux emergence, we use the Nudging Back and Forth, a data assimilation method with an anelastic convection model to reconstruct the convection zone below a solar active region from observed solar surface magnetograms. To mimic photosphere, vector magnetograms are computed using force free hypothesis. We find that the observed arcade system of AR9077-20000714 ( t he slinky ) of magnetic lines is actually formed by Ω and U loops generated in the convection zone. We generate temperature maps at top of the convective zone and find that high magnetic fields on either sides of the neutral line produce a local cooling by impeding the overturning motions.

  7. Solar rotation and activity in the past and their possible influence upon the evolution of life

    International Nuclear Information System (INIS)

    Geyer, E.H.

    1981-01-01

    It is proposed that the rotational angular momentum of the lower Main Sequence stars determines the intensity of their magnetic spot activity. As a consequence of this feedback coupling, the stellar rotation and the activity decay exponentially by magnetic braking of the induced stellar flare- and wind-activity. Therefore, the Sun should have rotated much faster and must have shown a very enhanced activity in its early history. This strong solar activity in the past could have influenced the evolution of terrestrial life, and may explain the stagnation of maritime life for about 2 x 10 9 yr, the diversification of species during the Cambrian formation, and the land conquest by life in the upper Silurian system. (Auth.)

  8. Solar rotation and activity in the past and their possible influence upon the evolution of life

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, E H [Bonn Univ. (Germany, F.R.). Sternwarte

    1981-06-01

    It is proposed that the rotational angular momentum of the lower Main Sequence stars determines the intensity of their magnetic spot activity. As a consequence of this feedback coupling, the stellar rotation and the activity decay exponentially by magnetic braking of the induced stellar flare- and wind-activity. Therefore, the Sun should have rotated much faster and must have shown a very enhanced activity in its early history. This strong solar activity in the past could have influenced the evolution of terrestrial life, and may explain the stagnation of maritime life for about 2 x 10/sup 9/ yr, the diversification of species during the Cambrian formation, and the land conquest by life in the upper Silurian system.

  9. Statistical properties of solar flares and coronal mass ejections through the solar cycle

    International Nuclear Information System (INIS)

    Telloni, Daniele; Antonucci, Ester; Carbone, Vincenzo; Lepreti, Fabio

    2016-01-01

    Waiting Time Distributions (WTDs) of solar flares are investigated all through the solar cycle. The same approach applied to Coronal Mass Ejections (CMEs) in a previous work is considered here for flare occurrence. Our analysis reveals that flares and CMEs share some common statistical properties, which result dependent on the level of solar activity. Both flares and CMEs seem to independently occur during minimum solar activity phases, whilst their WTDs significantly deviate from a Poisson function at solar maximum, thus suggesting that these events are correlated. The characteristics of WTDs are constrained by the physical processes generating those eruptions associated with flares and CMEs. A scenario may be drawn in which different mechanisms are actively at work during different phases of the solar cycle. Stochastic processes, most likely related to random magnetic reconnections of the field lines, seem to play a key role during solar minimum periods. On the other hand, persistent processes, like sympathetic eruptions associated to the variability of the photospheric magnetism, are suggested to dominate during periods of high solar activity. Moreover, despite the similar statistical properties shown by flares and CMEs, as it was mentioned above, their WTDs appear different in some aspects. During solar minimum periods, the flare occurrence randomness seems to be more evident than for CMEs. Those persistent mechanisms generating interdependent events during maximum periods of solar activity can be suggested to play a more important role for CMEs than for flares, thus mitigating the competitive action of the random processes, which seem instead strong enough to weaken the correlations among flare event occurrence during solar minimum periods. However, it cannot be excluded that the physical processes at the basis of the origin of the temporal correlation between solar events are different for flares and CMEs, or that, more likely, more sophisticated effects are

  10. Nrf2 Activation Protects against Solar-Simulated Ultraviolet Radiation in Mice and Humans.

    Science.gov (United States)

    Knatko, Elena V; Ibbotson, Sally H; Zhang, Ying; Higgins, Maureen; Fahey, Jed W; Talalay, Paul; Dawe, Robert S; Ferguson, James; Huang, Jeffrey T-J; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L; Honda, Tadashi; Proby, Charlotte M; Dinkova-Kostova, Albena T

    2015-06-01

    The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative, and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity, and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated are lower than those that arise in their wild-type counterparts. Pharmacologic Nrf2 activation by topical biweekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacologic Nrf2 activation lowers the expression of the pro-inflammatory factors IL6 and IL1β, and COX2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate endpoint for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. ©2015 American Association for Cancer Research.

  11. Solar Activity from 2006 to 2014 and Short-term Forecasts of Solar Proton Events Using the ESPERTA Model

    Energy Technology Data Exchange (ETDEWEB)

    Alberti, T.; Lepreti, F. [Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, Cubo 31C, 87036, Rende (CS) (Italy); Laurenza, M.; Storini, M.; Consolini, G. [INAF-IAPS, Via del Fosso del Cavaliere 100, I-00133, Roma (Italy); Cliver, E. W., E-mail: tommaso.alberti@unical.it, E-mail: monica.laurenza@iaps.inaf.it [National Solar Observatory, Boulder, CO (United States)

    2017-03-20

    To evaluate the solar energetic proton (SEP) forecast model of Laurenza et al., here termed ESPERTA, we computed the input parameters (soft X-ray (SXR) fluence and ∼1 MHz radio fluence) for all ≥M2 SXR flares from 2006 to 2014. This database is outside the 1995–2005 interval on which ESPERTA was developed. To assess the difference in the general level of activity between these two intervals, we compared the occurrence frequencies of SXR flares and SEP events for the first six years of cycles 23 (1996 September–2002 September) and 24 (2008 December–2014 December). We found a reduction of SXR flares and SEP events of 40% and 46%, respectively, in the latter period. Moreover, the numbers of ≥M2 flares with high values of SXR and ∼1 MHz fluences (>0.1 J m{sup −2} and >6 × 10{sup 5} sfu × minute, respectively) are both reduced by ∼30%. A somewhat larger percentage decrease of these two parameters (∼40% versus ∼30%) is obtained for the 2006–2014 interval in comparison with 1995–2005. Despite these differences, ESPERTA performance was comparable for the two intervals. For the 2006–2014 interval, ESPERTA had a probability of detection (POD) of 59% (19/32) and a false alarm rate (FAR) of 30% (8/27), versus a POD = 63% (47/75) and an FAR = 42% (34/81) for the original 1995–2005 data set. In addition, for the 2006–2014 interval the median (average) warning time was estimated to be ∼2 hr (∼7 hr), versus ∼6 hr (∼9 hr), for the 1995–2005 data set.

  12. Solar and Geomagnetic Activity Variations Correlated to Italian M6+ Earthquakes Occurred in 2016

    Science.gov (United States)

    Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino

    2017-04-01

    Between August 2016 and October 2016 in Italy were recorded three strong earthquakes: M6.2 on August 2016 at 01:36:32 UTC; M6.1 on October 26, 2016 at 19:18:08 UTC and M6,6 on October 30, 2016 at 06:40:18 UTC. The authors of this study wanted to verify the existence of a correlation between these earthquakes and solar/geomagnetic activity. To confirming or not the presence of this kind of correlation, the authors analyzed the conditions of Spaceweather "near Earth" and the characteristics of the Earth's geomagnetic field in the hours that preceded the three earthquakes. The data relating to the three earthquakes were provided by the United States Geological Survey (USGS). The data on ion density used to realize the correlation study are represented by: solar wind ion density variation detected by ACE (Advanced Composition Explorer) Satellite, in orbit near the L1 Lagrange point, at 1.5 million of km from Earth, in direction of the Sun. The instrument used to perform the measurement of the solar wind ion density is the Electron, Proton, and Alpha Monitor (EPAM) instrument, equipped on the ACE Satellite. To conduct the study, the authors have taken in consideration the variation of the solar wind protons density of three different energy fractions: differential proton flux 1060-1900 keV (p/cm^2-sec-ster-MeV); differential proton flux 761-1220 keV (p/cm^2-sec-ster-MeV); differential proton flux 310-580 keV (p/cm^2-sec-ster-MeV). Geomagnetic activity data were provided by Tromsø Geomagnetic Observatory (TGO), Norway; by Scoresbysund Geomagnetic Observatory (SCO), Greenland, Denmark; Dikson Geomagnetic Observatory (DIK), Russia and by Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation (IZMIRAN), Troitsk, Moscow Region. The results of the study, in agreement with what already ascertained by authors from 2012, have confirmed that the three strong Italian earthquakes were preceded by a clear increase of the solar wind proton density which

  13. Mechanical and experimental study on freeze proof solar powered adsorption cooling tube using active carbon/methanol working pair

    International Nuclear Information System (INIS)

    Zhao Huizhong; Zhang Min; Liu Zhenyan; Liu Yanling; Ma Xiaodong

    2008-01-01

    The freeze proof solar cooling tube, which can produce cooling capacity with the refrigerant temperature below 0 deg. C using solar light as energy and active carbon-methanol as working pair, was firstly designed and made in this research. This paper focused on mechanical and experimental study on a freeze proof solar powered adsorption cooling tube. The following experimental results could be concluded: at the solar radiation value between 15.3 and 17.1 MJ m -2 , the highest adsorbent bed temperature is below 110 deg. C. The freeze proof solar cooling tube's cooling capacity was about 87-99 kJ, and the coefficient of performance (COP) was more than 0.11 when the evaporation temperature was about -4 deg. C

  14. Relating Alfvén Wave Heating Model to Observations of a Solar Active Region

    Science.gov (United States)

    Yoritomo, J. Y.; Van Ballegooijen, A. A.

    2012-12-01

    We compared images from the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) with simulations of propagating and dissipating Alfvén waves from a three-dimensional magnetohydrodynamic (MHD) model (van Ballegooijen et. al 2011; Asgari-Targhi & van Ballegooijen 2012). The goal was to search for observational evidence of Alfvén waves in the solar corona and understand their role in coronal heating. We looked at one particular active region on the 5th of May 2012. Certain distinct loops in the SDO/AIA observations were selected and expanded. Movies were created from these selections in an attempt to discover transverse motions that may be Alfvén waves. Using a magnetogram of that day and the corresponding synoptic map, a potential field model was created for the active region. Three-dimensional MHD models for several loops in different locations in the active region were created. Each model specifies the temperature, pressure, magnetic field strength, average heating rate, and other parameters along the loop. We find that the heating is intermittent in the loops and reflection occurs at the transition region. For loops at larger and larger height, a point is reached where thermal non-equilibrium occurs. In the center this critical height is much higher than in the periphery of the active region. Lastly, we find that the average heating rate and coronal pressure decrease with increasing height in the corona. This research was supported by an NSF grant for the Smithsonian Astrophysical Observatory (SAO) Solar REU program and a SDO/AIA grant for the Smithsonian Astrophysical Observatory.

  15. On the relation between activity-related frequency shifts and the sunspot distribution over the solar cycle 23

    Directory of Open Access Journals (Sweden)

    Santos Ângela R. G.

    2017-01-01

    Full Text Available The activity-related variations in the solar acoustic frequencies have been known for 30 years. However, the importance of the different contributions is still not well established. With this in mind, we developed an empirical model to estimate the spot-induced frequency shifts, which takes into account the sunspot properties, such as area and latitude. The comparison between the model frequency shifts obtained from the daily sunspot records and those observed suggests that the contribution from a stochastic component to the total frequency shifts is about 30%. The remaining 70% is related to a global, long-term variation. We also propose a new observable to investigate the short-and mid-term variations of the frequency shifts, which is insensitive to the long-term variations contained in the data. On the shortest time scales the variations in the frequency shifts are strongly correlated with the variations in the total area covered by sunspots. However, a significant loss of correlation is still found, which cannot be fully explained by ignoring the invisible side of the Sun when accounting for the total sunspot area. We also verify that the times when the frequency shifts and the sunspot areas do not vary in a similar way tend to coincide with the times of the maximum amplitude of the quasi-biennial variations found in the seismic data.

  16. Daytime descending intermediate layers observed over a sub-tropical Indian station Waltair during low-solar activity period

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    K. Niranjan

    2010-03-01

    Full Text Available Study on daytime descending intermediate layer over subtropical Indian station Waltair (17.7° N, 83.3° E geographic, 6.4° N, 10° E geomagnetic, 20° N dip located in the equatorial anomaly transition region, using an IPS 42 Digital Ionosonde during the low solar activity year 2004 showed that the layers occur in the altitude range of 140–160 km with maximum occurrence during winter solstice. The layers observed during daytime occur with a double peak variation throughout the year with less occurrence probability and shorter duration presence during forenoon hours. The morning layer descent was associated with a density increase where as during afternoon hours a decrease in density was observed. The downward drift velocity was about 8 km/h during morning hours and between 7–11 km/h during afternoon hours, with a low descent rate of around 4.5 km/h during summer morning hours. The results indicate the presence of a 6 h tide at this location as observed from the characteristics of the descending layers, unlike at majority of locations where a significant semi diurnal trend is observed. The study brings out the complex nature of the tidal interaction at different locations.

  17. Statistical analysis of geomagnetic field variations during solar eclipses

    Science.gov (United States)

    Kim, Jung-Hee; Chang, Heon-Young

    2018-04-01

    We investigate the geomagnetic field variations recorded by INTERMAGNET geomagnetic observatories, which are observed while the Moon's umbra or penumbra passed over them during a solar eclipse event. Though it is generally considered that the geomagnetic field can be modulated during solar eclipses, the effect of the solar eclipse on the observed geomagnetic field has proved subtle to be detected. Instead of exploring the geomagnetic field as a case study, we analyze 207 geomagnetic manifestations acquired by 100 geomagnetic observatories during 39 solar eclipses occurring from 1991 to 2016. As a result of examining a pattern of the geomagnetic field variation on average, we confirm that the effect can be seen over an interval of 180 min centered at the time of maximum eclipse on a site of a geomagnetic observatory. That is, demonstrate an increase in the Y component of the geomagnetic field and decreases in the X component and the total strength of the geomagnetic field. We also find that the effect can be overwhelmed, depending more sensitively on the level of daily geomagnetic events than on the level of solar activity and/or the phase of solar cycle. We have demonstrated it by dividing the whole data set into subsets based on parameters of the geomagnetic field, solar activity, and solar eclipses. It is suggested, therefore, that an evidence of the solar eclipse effect can be revealed even at the solar maximum, as long as the day of the solar eclipse is magnetically quiet.

  18. Normalizing the maximum permissible seal failure of the fuel cladding of VVER and the activity of the fission products in the coolant

    International Nuclear Information System (INIS)

    Luzanova, L.M.; Miglo, V.N.; Slavyagin, P.D.

    1993-01-01

    In most countries developing a nuclear power industry based on pressurized water reactors, one of the conditions for issuing a license under normal operating conditions for issuing a license stipulates that the fuel elements may not lose their hermetic seal either under normal operating conditions or during presumable disturbances of the conditions of normal use. At a conference on radiation safety the ALARA principle was taken to be fundamental, it being attempted to keep the activity of the coolant of the primary circuit, including the fission products emerging from unsealed fuel elements, to a level as low as reasonably possible. As many years of experience in the nuclear power industry have shown, nuclear power stations are in many cases operated with nonhermetic fuel elements in the core. Therefore, from the point of view of safety and economy, the best way to operate a power plant is to try to ensure maximum burnup of the fuel of the unsealed elements as they operate within the limits of safe activity of the fission products in the fuel circuits

  19. Design of Solar Harvested Semi Active RFID Transponder with Supercapacitor Storage

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    Gary Valentine

    2015-01-01

    Full Text Available This paper presents the analysis, design and manufacture of a low cost, low maintenance and long-range prototype of RFID transponder with continuous operability. A prototype of semi-active RFID transponder is produced with a range that can be extended via a DC input to allow all of the readers signal power to be reflected via backscatter modulation. The transponder is powered via solar harvested power which is selected over other energy harvesting technologies as it provides a greater energy density and lower cost. Solar has one major drawback in terms of providing a steady DC voltage in it needed a constant supply of sunlight. A method of power storage is proposed, and the use of a supercapacitor over a rechargeable battery is used as it has a longer lifespan due to higher recharge rates. The prototype underwent a series of experiments in various working environments and proves an effective solution in providing long lasting operability. The paper concludes the use of solar harvesting with supercapacitor storage has potential for further uses in external remote sensors used in the Internet of Things.

  20. Caspase-3 activation and DNA damage in pig skin organ culture after solar irradiation.

    Science.gov (United States)

    Bacqueville, Daniel; Mavon, Alain

    2008-01-01

    In the present study, a convenient and easy-to-handle skin organ culture was developed from domestic pig ears using polycarbonate Transwell culture inserts in 12-well plate. This alternative model was then tested for its suitability in analyzing the short-term effects of a single solar radiation dose (from 55 to 275 kJ.m(-2)). Differentiation of the pig skin was maintained for up to 48 h in culture, and its morphology was similar to that of fresh human skin. Solar irradiation induced a significant release of the cytosolic enzymes lactate dehydrogenase and extracellular signal-related kinase 2 protein in the culture medium 24 h after exposure. These photocytotoxic effects were associated with the formation of sunburn cells, thymine dimers and DNA strand breaks in both the epidermis and dermis. Interestingly, cell death was dose dependent and associated with p53 protein upregulation and strong caspase-3 activation in the basal epidermis. None of these cellular responses was observed in non-irradiated skin. Finally, topical application of a broad-spectrum UVB + A sunfilter formulation afforded efficient photoprotection in irradiated explants. Thus, the ex vivo pig ear skin culture may be a useful tool in the assessment of solar radiation-induced DNA damage and apoptosis, and for evaluating the efficacy of sunscreen formulations.