Science.gov

Sample records for high solar activity

  1. Solar Energy Project, Activities: Junior High Science.

    ERIC Educational Resources Information Center

    Tullock, Bruce, Ed.; And Others

    This guide contains lesson plans and outlines of science activities which present concepts of solar energy in the context of the junior high science curriculum. Each unit presents an introduction; objectives; skills and knowledge needed; materials; methods; questions; recommendations for further work; and a teacher information sheet. The teacher…

  2. Low-Dimensional Chaos of High-Latitude Solar Activity

    NASA Astrophysics Data System (ADS)

    Li, Qi-Xiu; Li, Ke-Jun

    2007-10-01

    The chaos of high-latitude solar activity has been investigated by determining the behavior of the monthly averaged polar facula counts obtained from the National Astronomical Observatory of Japan (NAOJ) on the basis of nonlinear dynamics theories and methods. It is found that the high-latitude solar activity is also governed by a low-dimensional chaotic attractor in both the northern and southern solar hemispheres, which is the same as that of the low-latitude solar activity. However, their maximal Lyapunov exponents are different, showing different strength of chaos. The maximal Lyapunov exponent (MLE) of polar faculae in the southern solar hemisphere is about 0.0211 ± 0.0003 (month-1), which is nearly consistent with the low-latitude Wolf sunspot numbers, while the MLE in the northern one is approximately 0.0944 ± 0.0066 (month-1), which is obviously greater than the above two.

  3. High Energetic Solar Flares in the Solar Minima Activity in Comparative Study with the Solar Maxima Activity from 1954 to 2014 and Their Effects on the Space Environment

    NASA Astrophysics Data System (ADS)

    Mohamed, Wael

    Solar 11-year cycle of solar activity is characterized by the rise and fall in the numbers and areas of sunspots. On solar maximum activity, many flares and CMEs can affect the near-earth space environment. But on the solar minimum activity, there are sometimes solar proton events, (e.g. High Energetic Solar Proton Flares on the declining phase of solar cycle 22 for M.A.Mosalam Shaltout, 1995), have the same effect for those on the solar maximum activity or more. So, a study must be made for the ascending and descending phases of solar activity for a set of solar cycles (from 1954 to 2014) to confirm the conclusion of Mosalam Shaltout on the light of the present high quality observations from ground and by artificial satellites.

  4. Revisiting the question: Does high-latitude solar activity lead low-latitude solar activity in time phase?

    SciTech Connect

    Kong, D. F.; Qu, Z. N.; Guo, Q. L.

    2014-05-01

    Cross-correlation analysis and wavelet transform methods are used to investigate whether high-latitude solar activity leads low-latitude solar activity in time phase or not, using the data of the Carte Synoptique solar filaments archive from 1919 March to 1989 December. From the cross-correlation analysis, high-latitude solar filaments have a time lead of 12 Carrington solar rotations with respect to low-latitude ones. Both the cross-wavelet transform and wavelet coherence indicate that high-latitude solar filaments lead low-latitude ones in time phase. Furthermore, low-latitude solar activity is better correlated with high-latitude solar activity of the previous cycle than with that of the following cycle, which is statistically significant. Thus, the present study confirms that high-latitude solar activity in the polar regions is indeed better correlated with the low-latitude solar activity of the following cycle than with that of the previous cycle, namely, leading in time phase.

  5. Topside electron temperature models for low and high solar activity

    NASA Astrophysics Data System (ADS)

    Pandey, V. K.; Sethi, N. K.; Mahajan, K. K.

    It is now well known that in the topside ionosphere thermal conduction from the protonosphere becomes the dominant factor over the heating and loss terms in shaping the ionospheric electron temperature (Te) profile. By analyzing a limited database of incoherent scatter (IS) Te measurements, Mahajan and Pandey [J. Geophys. Res. 85 (1980) 213] reported a correlation between the electron heat flux and electron density in the topside ionosphere. Since attention has been steadily mounting for the empirical modeling of Te, we now exploit the large database of IS measurements of Te and Ne at Arecibo during 1989-1990 (high solar activity), as well as during 1975-1976 (low solar activity) for this purpose. We again find a functional relationship between heat flux and electron density in the topside ionosphere during both the solar activities. These functional relationships are used to generate topside Te profiles.

  6. High flare activity and redistribution of solar global magnetic fields

    NASA Astrophysics Data System (ADS)

    Bumba, V.; Hejna, L.; Gesztelyi, L.

    It is demonstrated that, both on the global scale and on the scale of large and complex active regions, high flare activity is closely related to changes in the whole background magnetic-field distribution. It is found that the disturbances of the normal course of magnetic active longitudes (MAL) during the years 1965-1980 correlated with the maxima of flare activity, while the mode of the MAL distribution correlated with the mean level of solar flare numbers. The development of activity during the last two submaxima of the 21st cycle, especially the formation of the white-light flare region of April 1984, were parts of global processes in the solar atmosphere. They were accompanied by a complete reorganization of the MAL patterns, background field sector structure, and coronal holes.

  7. Topside electron temperature models for low and high solar activity

    NASA Astrophysics Data System (ADS)

    Pandey, V.; Sethi, N.; Mahajan, K.

    It is now well known that in the topside ionosphere, thermal conduction from the protonosphere becomes the dominant factor over the "heating" and "loss" terms in shaping the ionospheric electron temperature (Te) profile. By analyzing a limited data base of incoherent scatter (i.s.) Te measurements , Mahajan and Pandey (1980) reported a correlation between the topside electron heat flux and electron density, Ne at 400 km. In the recent years, since attention has been steadily mounting for the empirical modelling of Te, in this paper we exploit the large data base of i.s. measurements of Te and Ne at Arecibo, during 1989 -90 (high solar activity), as well as during 1975-76 ( low solar activity). We again find a functional relationship between heat flux and electron density in the topside ionosphere during both the solar activities. These functional relationships are used to generate topside Te profiles. As the current IRI Te model does not include variations with solar activity, the present work can contribute in improving the topside Te model.

  8. High resolution studies of complex solar active regions

    NASA Astrophysics Data System (ADS)

    Deng, Na

    Flares and Coronal Mass Ejections (CMEs) are energetic events, which can even impact the near-Earth environment and are the principal source of space weather. Most of them originate in solar active regions. The most violent events are produced in sunspots with a complex magnetic field topology. Studying their morphology and dynamics is helpful in understanding the energy accumulation and release mechanisms for flares and CMEs, which are intriguing problems in solar physics. The study of complex active regions is based on high-resolution observations from space missions and new instruments at the Big Bear Solar Observatory (BBSO). Adaptive optics (AO) in combination with image restoration techniques (speckle masking imaging) can achieve improved image quality and a spatial resolution (about 100 km on the solar surface) close to the diffraction limit of BBSO's 65 cm vacuum telescope. Dopplergrams obtained with a two-dimensional imaging spectrometer combined with horizontal flow maps derived with Local Correlation Tracking (LCT) provide precise measurements of the three-dimensional velocity field in sunspots. Magnetic field measurements from ground- and space-based instruments complement these data. At the outset of this study, the evolution and morphology of a typical round sunspot are described in some detail. The sunspot was followed from disk center to the limb, thus providing some insight into the geometry of the magnetic flux system. Having established a benchmark for a stable sunspot, the attention is turned to changes of the sunspot structure associated with flares and CMEs. Rapid penumbral decay and the strengthening of sunspot umbrae are manifestations of photospheric magnetic field changes after a flare. These sudden intensity changes are interpreted as a result of magnetic reconnection during the flare, which causes the magnetic field lines to be turned from more inclined to more vertical. Strong photospheric shear flows along the flaring magnetic

  9. Equatorial Total Electron Content (TEC) at Low and High Solar Activity

    NASA Astrophysics Data System (ADS)

    Mene, M. N.; Obrou, O. K.; Kobea, A. T.; Zaka, K. Z.

    2007-05-01

    Total Electron Content derived from ionosonde data recorded at Korhogo (Lat=9.33 N, Long =5.43 W, Dip = 0.67 S) are compared to the Internatial Reference Ionosphere (IRI) model predicted TEC for high (1999) and low (1994) solar activity conditions. The result shows that the TEC has a solar activity and seasonal dependence. The IRI predicted values are closer to the observed TEC at high solar activity. However, at low solar activity the IRI overestimates the observed TEC. The deviation is more prominent in equinox during the time range 0900 to 2300 local time. The deviation is estimated to 60% of the observed TEC.

  10. Solar Activity and Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.

    2006-01-01

    Our Sun is a dynamic, ever-changing star. In general, its atmosphere displays major variation on an 11-year cycle. Throughout the cycle, the atmosphere occasionally exhibits large, sudden outbursts of energy. These "solar eruptions" manifest themselves in the form of solar flares, filament eruptions, coronal mass ejections (CMEs), and energetic particle releases. They are of high interest to scientists both because they represent fundamental processes that occur in various astrophysical context, and because, if directed toward Earth, they can disrupt Earth-based systems and satellites. Research over the last few decades has shown that the source of the eruptions is localized regions of energy-storing magnetic field on the Sun that become destabilized, leading to a release of the stored energy. Solar scientists have (probably) unraveled the basic outline of what happens in these eruptions, but many details are still not understood. In recent years we have been studying what triggers these magnetic eruptions, using ground-based and satellite-based solar observations in combination with predictions from various theoretical models. We will present an overview of solar activity and solar eruptions, give results from some of our own research, and discuss questions that remain to be explored.

  11. High Energy Phenomena on the Sun. [conference on solar activity effects and solar radiation

    NASA Technical Reports Server (NTRS)

    Ramaty, R. (Editor); Stone, R. G. (Editor)

    1973-01-01

    The proceedings of a symposium of high energy phenomena on the sun are presented. The subjects discussed include the following: (1) flare theories and optical observations, (2) microwave and hard X-ray observations, (3) ultraviolet and soft X-ray emissions, (4) nuclear reactions in solar flares, (5) energetic particles from the sun, (6) magnetic fields and particle storage, and (7) radio emissions in the corona and interplanetary space.

  12. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (∼0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ∼ 3 km s‑1) as well as modest non-thermal velocities (with an average of ∼24 km s‑1 and the peak of the distribution at ∼15 km s‑1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  13. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (˜0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ˜ 3 km s‑1) as well as modest non-thermal velocities (with an average of ˜24 km s‑1 and the peak of the distribution at ˜15 km s‑1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  14. Investigation of solar active regions at high resolution by balloon flights of the solar optical universal polarimeter, extended definition phase

    NASA Technical Reports Server (NTRS)

    Tarbell, Theodore D.

    1993-01-01

    Technical studies of the feasibility of balloon flights of the former Spacelab instrument, the Solar Optical Universal Polarimeter, with a modern charge-coupled device (CCD) camera, to study the structure and evolution of solar active regions at high resolution, are reviewed. In particular, different CCD cameras were used at ground-based solar observatories with the SOUP filter, to evaluate their performance and collect high resolution images. High resolution movies of the photosphere and chromosphere were successfully obtained using four different CCD cameras. Some of this data was collected in coordinated observations with the Yohkoh satellite during May-July, 1992, and they are being analyzed scientifically along with simultaneous X-ray observations.

  15. Investigation of solar active regions at high resolution by balloon flights of the solar optical universal polarimeter, definition phase

    NASA Technical Reports Server (NTRS)

    Tarbell, Theodore D.; Topka, Kenneth P.

    1992-01-01

    The definition phase of a scientific study of active regions on the sun by balloon flight of a former Spacelab instrument, the Solar Optical Universal Polarimeter (SOUP) is described. SOUP is an optical telescope with image stabilization, tunable filter and various cameras. After the flight phase of the program was cancelled due to budgetary problems, scientific and engineering studies relevant to future balloon experiments of this type were completed. High resolution observations of the sun were obtained using SOUP components at the Swedish Solar Observatory in the Canary Islands. These were analyzed and published in studies of solar magnetic fields and active regions. In addition, testing of low-voltage piezoelectric transducers was performed, which showed they were appropriate for use in image stabilization on a balloon.

  16. Solar Energy Education. Renewable energy activities for junior high/middle school science

    SciTech Connect

    Not Available

    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)

  17. Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

    NASA Technical Reports Server (NTRS)

    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.

  18. On the high correlation between long-term averages of solar wind speed and geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Crooker, N. U.; Feynman, J.; Gosling, J. T.

    1977-01-01

    Six-month and yearly averages of solar-wind speed from 1962 to 1975 are shown to be highly correlated with geomagnetic activity as measured by averages of the Ap index. On the same time scale the correlation between the southward component of the interplanetary magnetic field and geomagnetic activity is poor. Previous studies with hourly averages gave opposite results. The better correlation with the southward component on an hourly time scale is explained by its large variation compared with the relatively constant solar-wind speed. However, on a yearly time scale the magnitude of the variations in both parameters are about the same. This problem can be solved by invoking an energy transfer mechanism which is proportional to the first power of the southward component and a higher power of the solar-wind speed.

  19. High-wavenumber solar f-mode strengthening prior to active region formation

    NASA Astrophysics Data System (ADS)

    Singh, Nishant; Raichur, Harsha; Brandenburg, Axel

    2016-05-01

    We report a systematic strengthening of the local solar surface mode, i.e. the f-mode, 1-2 days prior to the emergence of an active region (AR) in the same (corotating) location while no indication can yet be seen in the magnetograms. Our study is motivated by earlier numerical findings of Singh et al. (2014) which showed that, in the presence of a nonuniform magnetic field that is concentrated a few scale heights below the surface, the f-mode fans out in the diagnostic kΩ diagram at high wavenumbers. Here we explore this possibility using data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, and show for four ARs 11130, 11158, 11768, and 12051, that at large latitudinal wavenumbers (corresponding to horizontal scales of around 3000 km), the f-mode displays strengthening about two days prior to AR formation and thus provides a new precursor for AR formation. The idea that the f-mode is perturbed days before any visible magnetic activity occurs on the surface can be important in constraining dynamo models aimed at understanding the global magnetic activity of the Sun.

  20. Activities for Teaching Solar Energy.

    ERIC Educational Resources Information Center

    Mason, Jack Lee; Cantrell, Joseph S.

    1980-01-01

    Plans and activities are suggested for teaching elementary children about solar energy. Directions are included for constructing a flat plate collector and a solar oven. Activities for a solar field day are given. (SA)

  1. Solar activity variability in the IRI at high latitudes: Comparisons with GPS total electron content

    NASA Astrophysics Data System (ADS)

    Themens, David R.; Jayachandran, P. T.

    2016-04-01

    Total electron content (TEC) measurements from 10 dual-frequency GPS receivers in the Canadian High Arctic Ionospheric Network (CHAIN) are used to evaluate the performance of International Reference Ionosphere (IRI)-2007 within the Canadian sector. Throughout the region, we see systematic underestimation of daytime TEC, particularly at solar maximum, where summer and equinox root-mean-square errors reach as high as 14 total electron content units, 1 TECU = 1016 el m-2 (TECU). It is also shown that the use of a monthly IG index, in place of the IRI's standard IG12 index, leads to an improvement in TEC specification by up to 3 TECU in the polar cap and up to 6 TECU in the subauroral region during periods of short-term, large amplitude changes in solar activity. On diurnal timescales, variability in TEC is found to be underestimated by the IRI, during equinox periods, by up to 40% at subauroral latitudes and up to 70% in the polar cap region. During the winter, diurnal variations are overestimated by up to 40% in the subauroral region and are underestimated within the polar cap by up to 80%. Using collocated ionosonde data, we find IRI bottomside TEC to be within 1 TECU of observation with errors largest during the equinoxes. For the topside we find good agreement during the winter but significant underestimation of topside TEC by the IRI during summer and equinox periods, exceeding 6 TECU at times. By ingesting measured NmF2 into the IRI, we show that the topside thickness parameterization is the source of the bulk of the observed TEC errors.

  2. IPS of the Radio Source 3C48 During the Periods of Low and High Solar Activity

    NASA Astrophysics Data System (ADS)

    Aguilar-Rodriguez, E.; Tyul'bashev, S. A.; Chashei, I. V.; Romero-Hernandez, E.

    2015-12-01

    We present a comparative study of three techniques used to estimate the scintillation index (m) using interplanetary scintillation (IPS) observations carried out by the Big Scanning Array (BSA), that operates at a frequency of 111 MHz. These techniques are based on: rms analysis on-source and off-source (classic), Fourier and wavelet transforms. IPS data are analyzed separately for the period of low solar activity (2007-2009), and for the year 2013, near the solar activity maximum. Our results show that in general, these methods are equivalent. We analyze the radial dependence of scintillation index at meter wavelengths during these two periods. It is found that the observed radial dependence of scintillation index during both periods of the cycle 24 is more flat than the theoretical dependence expected for the case of solar wind spherical symmetry. This flattening can be explained in terms of the influence of the heliospheric current sheet during periods of low solar activity, and the influence of solar disturbances, such as coronal mass ejections (CMEs), for periods of high solar activity.

  3. Procedures for minimizing the effects of high solar activity on satellite tracking and ephemeris generation

    NASA Astrophysics Data System (ADS)

    Bredvik, Gordon D.

    1990-12-01

    We are currently experiencing a period of high solar radiation combined with wide short-term fluctuations in the radiation. The short-term fluctuations, especially when combined with highly energetic solar flares, can adversely affect the mission of U.S. Space Command's Space Surveillance Center (SSC) which catalogs and tracks the satellites in orbit around the Earth. Rapidly increasing levels of solar electromagnetic and/or particle radiation (solar wind) causes atmospheric warming, which, in turn, causes the upper-most portions of the atmosphere to expand outward, into the regime of low altitude satellites. The increased drag on satellites from this expansion can cause large, unmodeled, in-track displacements, thus undermining the SSC's ability to track and predict satellite position. On 13 March 1989, high solar radiation levels, combined with a high-energy solar flare, caused an exceptional amount of short-term atmospheric warming. The SSC temporarily lost track of over 1300 low altitude satellites--nearly half of the low altitude satellite population. Observational data on satellites that became lost during the days following the 13 March 'solar event' was analyzed and compared with the satellites' last element set prior to the event (referred to as a geomagnetic storm because of the large increase in magnetic flux in the upper atmosphere). The analysis led to a set of procedures for reducing the impact of future geomagnetic storms. These procedures adjust selected software limit parameters in the differential correction of element sets and in the observation association process and must be manually initiated at the onset of a geomagnetic storm. Sensor tasking procedures must be adjusted to ensure that a minimum of four observations per day are received for low altitude satellites. These procedures have been implemented and, thus far, appear to be successful in minimizing the effect of subsequent geomagnetic storms on satellite tracking and ephemeris

  4. Procedures for minimizing the effects of high solar activity on satellite tracking and ephemeris generation

    NASA Technical Reports Server (NTRS)

    Bredvik, Gordon D.

    1990-01-01

    We are currently experiencing a period of high solar radiation combined with wide short-term fluctuations in the radiation. The short-term fluctuations, especially when combined with highly energetic solar flares, can adversely affect the mission of U.S. Space Command's Space Surveillance Center (SSC) which catalogs and tracks the satellites in orbit around the Earth. Rapidly increasing levels of solar electromagnetic and/or particle radiation (solar wind) causes atmospheric warming, which, in turn, causes the upper-most portions of the atmosphere to expand outward, into the regime of low altitude satellites. The increased drag on satellites from this expansion can cause large, unmodeled, in-track displacements, thus undermining the SSC's ability to track and predict satellite position. On 13 March 1989, high solar radiation levels, combined with a high-energy solar flare, caused an exceptional amount of short-term atmospheric warming. The SSC temporarily lost track of over 1300 low altitude satellites--nearly half of the low altitude satellite population. Observational data on satellites that became lost during the days following the 13 March 'solar event' was analyzed and compared with the satellites' last element set prior to the event (referred to as a geomagnetic storm because of the large increase in magnetic flux in the upper atmosphere). The analysis led to a set of procedures for reducing the impact of future geomagnetic storms. These procedures adjust selected software limit parameters in the differential correction of element sets and in the observation association process and must be manually initiated at the onset of a geomagnetic storm. Sensor tasking procedures must be adjusted to ensure that a minimum of four observations per day are received for low altitude satellites. These procedures have been implemented and, thus far, appear to be successful in minimizing the effect of subsequent geomagnetic storms on satellite tracking and ephemeris

  5. Physics of solar activity

    NASA Technical Reports Server (NTRS)

    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.

  6. Ion temperature of low-latitude and mid-latitude topside ionosphere for high solar activity

    NASA Astrophysics Data System (ADS)

    Cai, Lei; Zhang, Donghe; Hao, Yongqiang; Xiao, Zuo

    The International Reference Ionosphere (IRI) describes the day and night latitudinal variation of ion temperature at 430 km with two functions using AEROS satellite measurements. The ion temperature at this height as one of the boundary parameters is used to make the ion temperature profile represented by a Booker-function. Since the low-latitude and mid-latitude topside ionospheric ion temperature has been measured with the Ionopsheric Plasma and Elec-trodynamics Instrument (IPEI) onboard Rocsat-1 satellite at about 600 km during the high solar activity years from 2000 to 2002, a new boundary at 600 km can be set for the ion temperature modeling. The latitudinal variation of ion temperature could be approximated by Epstein family of functions for different local time sectors. Furthermore, the longitudinal and seasonal variations are also taken into account to decide the fitting parameters. Only the magnetic quiet time data (Kp <3) are used for the statistical study. The results are compared with IRI-2007 model. In addition, events when Kp >4 are also analyzed to feature the ion temperature characteristic during the magnetic disturbance time condition. Combined with the IPEI field-aligned ion flow velocities and the plasma temperatures measured by the Special Sensors-Ions, Electrons, and Scintillation (SSIES) thermal plasma analysis package on board the DMSP F13 and F15 satellites, several feasible ion heating and heat loss mechanisms are summarized to interpret the ion temperature crests and toughs for different local time sectors, seasonal and longitudinal variations.

  7. PCA Analysis of the Geomagnetic Field at Mid-Latitude Regions during High Solar Activity

    NASA Astrophysics Data System (ADS)

    Natali, Maria Paula; Meza, Amalia Margarita

    2016-07-01

    Our study is focused on the analysis of the geomagnetic variability of the H, D and Z components in the Northern hemisphere at mid-latitudes. We analyze two different local times, noon and night, recorded by 22 permanent observatories distributed over Europe and North America during a period of four years of high solar activity comprising 2000-2003. We used Principal Component Analysis (PCA) in order to identify the spatial and temporal variations of the geomagnetic field components. This technique produces a quite compact representation of the data by defining an orthonormal base derived from correlation within the data set. This helps us to identify possible causes of seasonal variations and anomalies, linking them with already observed currents. In fact, the analysis of PCA amplitudes and modes support our interpretation of the spectral and statistical features of the geomagnetic field. Using the first two modes we reconstruct more than 90% of the original signal for the European and North American region. The obtained results reconfirm the existence of a latitudinal dependence in the geomagnetic components during nighttime hours, associated with the ring current. During noon, the first mode represent the dominant component of the current originated by the ionosphere, while the second mode show the presence of a longitudinal variation at both sides of the longitudes with zero declination for Europe and North America.

  8. Solar cell activation system

    SciTech Connect

    Apelian, L.

    1983-07-05

    A system for activating solar cells involves the use of phosphorescent paint, the light from which is amplified by a thin magnifying lens and used to activate solar cells. In a typical system, a member painted with phosphorescent paint is mounted adjacent a thin magnifying lens which focuses the light on a predetermined array of sensitive cells such as selenium, cadmium or silicon, mounted on a plastic board. A one-sided mirror is mounted adjacent the cells to reflect the light back onto said cells for purposes of further intensification. The cells may be coupled to rechargeable batteries or used to directly power a small radio or watch.

  9. Commission 10: Solar Activity

    NASA Astrophysics Data System (ADS)

    van Driel-Gesztelyi, Lidia; Schrijver, Carolus J.; Klimchuk, James A.; Charbonneau, Paul; Fletcher, Lyndsay; Hasan, S. Sirajul; Hudson, Hugh S.; Kusano, Kanya; Mandrini, Cristina H.; Peter, Hardi; Vršnak, Bojan; Yan, Yihua

    2012-04-01

    Commission 10 of the International Astronomical Union has more than 650 members who study a wide range of activity phenomena produced by our nearest star, the Sun. Solar activity is intrinsically related to solar magnetic fields and encompasses events from the smallest energy releases (nano- or even picoflares) to the largest eruptions in the Solar System, coronal mass ejections (CMEs), which propagate into the Heliosphere reaching the Earth and beyond. Solar activity is manifested in the appearance of sunspot groups or active regions, which are the principal sources of activity phenomena from the emergence of their magnetic flux through their dispersion and decay. The period 2008-2009 saw an unanticipated extended solar cycle minimum and unprecedentedly weak polar-cap and heliospheric field. Associated with that was the 2009 historical maximum in galactic cosmic rays flux since measurements begun in the middle of the 20th Century. Since then Cycle 24 has re-started solar activity producing some spectacular eruptions observed with a fleet of spacecraft and ground-based facilities. In the last triennium major advances in our knowledge and understanding of solar activity were due to continuing success of space missions as SOHO, Hinode, RHESSI and the twin STEREO spacecraft, further enriched by the breathtaking images of the solar atmosphere produced by the Solar Dynamic Observatory (SDO) launched on 11 February 2010 in the framework of NASA's Living with a Star program. In August 2012, at the time of the IAU General Assembly in Beijing when the mandate of this Commission ends, we will be in the unique position to have for the first time a full 3-D view of the Sun and solar activity phenomena provided by the twin STEREO missions about 120 degrees behind and ahead of Earth and other spacecraft around the Earth and ground-based observatories. These new observational insights are continuously posing new questions, inspiring and advancing theoretical analysis and

  10. Investigation of Ionospheric Slab Thickness behaviour over Rome during high solar activity period

    NASA Astrophysics Data System (ADS)

    Trivedi, Richa; Gwal, Ashok Kumar; Jain, Sudhir

    The subject of the present study is to analyze the characteristic variations of the ionospheric slab thickness at Rome (41°N, 12°E, LT= (UT+1h), DIP=57°.4) for the period August, 2011 to July, 2012. The work deals with diurnal, seasonal, solar and magnetic activity variations of slab thickness. We observed that the seasonal mean value of slab thickness is higher during summer months than equinox and winter months and the mean diurnal variations of the slab thickness characterised with night-time values that are substantially higher than the day-time values during winter (night-to-day ratio between 1.01), but higher day-time and lower night-time values during summer (night-to-day ratio of 0.65). The slab thickness decreases with increase in solar flux value for mid-latitude. The results have been compared with the earlier ones and discussed in terms of possible source mechanism responsible for the variation of slab thickness at mid-latitude region. Keywords: F2 layer critical frequency (foF2); F2-layer electron density (NmF2); Slab thickness (τ); Solar Flux.

  11. Solar Energy Project, Activities: General Solar Topics.

    ERIC Educational Resources Information Center

    Tullock, Bruce, Ed.; And Others

    This guide contains lesson plans and outlines of activities which introduce students to concepts and issues relating to solar energy. Lessons frequently presented in the context of solar energy as it relates to contemporary energy problems. Each unit presents an introduction; objectives; necessary skills and knowledge; materials; method;…

  12. Solar activity predicted with artificial intelligence

    NASA Astrophysics Data System (ADS)

    Lundstedt, Henrik

    The variability of solar activity has been described as a non-linear chaotic dynamic system. AI methods are therefore especially suitable for modelling and predicting solar activity. Many indicators of the solar activity have been used, such as sunspot numbers, F 10.7 cm solar radio flux, X-ray flux, and magnetic field data. Artificial neural networks have also been used by many authors to predict solar cycle activity. Such predictions will be discussed. A new attempt to predict the solar activity using SOHO/MDI high-time resolution solar magnetic field data is discussed. The purpose of this new attempt is to be able to predict episodic events and to predict occurrence of coronal mass ejections. These predictions will be a part of the Lund Space Weather Model.

  13. A theoretical study of the high-latitude winter F region at solar minimum for low magnetic activity

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Raitt, W. J.; Schunk, R. W.

    1981-01-01

    A simple plasma convection model is combined with an ionospheric-atmospheric composition model in order to study the high-latitude winter F region at the solar minimum for low magnetic activity. The high latitude ionospheric features, such as the main trough, the ionization hole, the tongue of ionization, the aurorally produced ionization peaks, and the universal time effects are a natural consequence of the competition between the various chemical and transport processes known to be operating in the high-latitude ionosphere. In the polar hole, the F region peak electron density is below 300 km, and the dominant process at 300 km for NO(+) ions is diffusion.

  14. Commission 10: Solar Activity

    NASA Astrophysics Data System (ADS)

    Klimchuk, James A.; van Driel-Gesztelyi, Lidia; Schrijver, Carolus J.; Melrose, Donald B.; Fletcher, Lyndsay; Gopalswamy, Natchimuthuk; Harrison, Richard A.; Mandrini, Cristina H.; Peter, Hardi; Tsuneta, Saku; Vršnak, Bojan; Wang, Jing-Xiu

    Commission 10 deals with solar activity in all of its forms, ranging from the smallest nanoflares to the largest coronal mass ejections. This report reviews scientific progress over the roughly two-year period ending in the middle of 2008. This has been an exciting time in solar physics, highlighted by the launches of the Hinode and STEREO missions late in 2006. The report is reasonably comprehensive, though it is far from exhaustive. Limited space prevents the inclusion of many significant results. The report is divided into the following sections: Photosphere and chromosphere; Transition region; Corona and coronal heating; Coronal jets; flares; Coronal mass ejection initiation; Global coronal waves and shocks; Coronal dimming; The link between low coronal CME signatures and magnetic clouds; Coronal mass ejections in the heliosphere; and Coronal mass ejections and space weather. Primary authorship is indicated at the beginning of each section.

  15. North-South differences in the Earth's high-latitude upper atmosphere dynamics: Influence of solar activity and seasonal variations

    NASA Astrophysics Data System (ADS)

    Förster, Matthias; Cnossen, Ingrid

    2014-05-01

    Recent observations have shown that the upper thermospheric/ionospheric response to solar wind and IMF dependent drivers of the magnetosphere-ionosphere-thermosphere (M-I-T) system can be very dissimilar in the Northern and Southern Hemisphere. We present statistical studies of the high-latitude upper thermospheric neutral wind circulation patterns obtained from almost a decade of measurements with an accelerometer on board the CHAMP spacecraft. The influence of the solar activity and the dependence on seasonal variations is analysed with respect to average cross-polar wind velocities and high-latitude neutral wind vorticity values. Using the Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model, on the other hand, we simulated representative equinox as well as solstice intervals for low and high solar activity conditions. For the simulations, we used on the one hand side symmetric dipole and on the other realistic (IGRF) geomagnetic field configurations. The comparative survey of both the numerical simulation and the statistical observation results show some prominent asymmetries between the two hemispheres, which are caused by the different geographic-geomagnetic offsets and/or the different patterns of geomagnetic flux densities. The average cross-polar neutral wind velocities show a distinct seasonal variation with minimum values during the respective hemispheric winter solstice. The neutral wind vorticity values are generally larger in the Northern than the Southern Hemisphere, except for northern winter solstice conditions. The hemispheric differences become larger for higher solar activity and show a semidiurnal variation. In contrast, the spatial variance of the upper thermospheric neutral wind is usually considerably larger in the polar region of the Southern Hemisphere compared with the Northern, and the hemispheric difference shows a strong semidiurnal variation.

  16. Distant Futures of Solar Activity

    NASA Astrophysics Data System (ADS)

    Ayres, Thomas

    1997-07-01

    We will explore possible future fates of solar magnetic activity through high-S/N ultraviolet spectra of the ancient Sun analog, Arcturus {K2 III}. The fundamental mechanisms that drive the hot {T>10^6 K} coronae of cool stars remain elusive. Solving the mystery is a central theme of the ``solar-stellar connection;'' whose importance extends beyond astronomy to areas ranging from basic plasma physics to solar-terrestrial relations. A significant property of the activity is that it subsides with age: G dwarfs in young clusters are intense coronal sources, whereas old low mass K giants are so feable in soft X-rays that most are below current detection limits. For that reason, historical studies of activity have been biased towards the younger stars. Now HST/STIS easily can record faint coronal proxies {like Si IV and C IV} in nearby cool subgiants and giants, thereby mitigating the de facto age discrimination. In the solar neighborhood the brightest single star of advanced age {9-11 Gyr} is Alpha Bootis {K2 III}. Previous studies have placed the archetype red giant firmly in the ``coronal graveyard.'' Our project focuses on understanding the ``basal'' chromosphere; molecular cooling catastrophes and the structure of the passive ``COmosphere;'' the dynamics and energy balance of the residual subcoronal gas; and mass loss mechanisms. {This program is a carryover from a failed Cycle 5 GHRS observation.}

  17. Activation of solar flares

    SciTech Connect

    Cargill, P.J.; Migliuolo, S.; Hood, A.W.

    1984-11-01

    The physics of the activation of two-ribbon solar flares via the MHD instability of coronal arcades is presented. The destabilization of a preflare magnetic field is necessary for a rapid energy release, characteristic of the impulsive phase of the flare, to occur. The stability of a number of configurations are examined, and the physical consequences and relative importance of varying pressure profiles and different sets of boundary conditions (involving field-line tying) are discussed. Instability modes, driven unstable by pressure gradients, are candidates for instability. Shearless vs. sheared equilibria are also discussed. (ESA)

  18. Midlatitude ionospheric responses to the 2013 SSW under high solar activity

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Wu, Chen; Zhang, Shaodong; Ning, Baiqi; Huang, Xueqin; Zhong, Dingkun; Qi, Hao; Wang, Jin; Huang, Liang

    2016-01-01

    Ionospheric responses to sudden stratospheric warming (SSW) are not well understood, particularly in the midlatitudes and under high solar conditions. During the 2013 SSW, ionospheric disturbances were observed in eight locations on the meridional chain from 30.5°N to 42.8°N in northern China. The midlatitude ionosphere responded strongly to the SSW despite being under high solar flux. The F2 layer maximum electric density increased by more than 80%, and the peak height was elevated more than 60 km. Well-set and organized semidiurnal variations were recorded in early and middle January during the SSW in eight observation locations. The expected foF2 decrease in the afternoon hours was not clearly discernible; however, nighttime enhancements occurred frequently. The time-period spectra of the average foF2 and zonal winds and meridional winds at altitudes of 86-95 km presented quasi-16 day planetary wave-like oscillations during the warming event. The coupling between the atmosphere and ionosphere may be strengthened by the quasi-16 day waves. The amplified diurnal, semidiurnal, and terdiurnal tides in foF2 were also recorded during the warming, in good agreement with earlier observations. Importantly, the variations in the semidiurnal tides included a 16 day periodic component, indicating that the modulated semidiurnal tides may transmit these 16 day planetary wave-like oscillations to the F region through wind dynamo. Although the PW-tide interaction theory is not novel, it is of significance in the midlatitude ionospheric response to SSW.

  19. How active was solar cycle 22?

    NASA Technical Reports Server (NTRS)

    Hoegy, W. R.; Pesnell, W. D.; Woods, T. N.; Rottman, G. J.

    1993-01-01

    Solar EUV observations from the Langmuir probe on Pioneer Venus Orbiter suggest that at EUV wavelengths solar cycle 22 was more active than solar cycle 21. The Langmuir probe, acting as a photodiode, measured the integrated solar EUV flux over a 13 1/2 year period from January 1979 to June 1992, the longest continuous solar EUV measurement. The Ipe EUV flux correlated very well with the SME measurement of L-alpha during the lifetime of SME and with the UARS SOLSTICE L-alpha from October 1991 to June 1992 when the Ipe measurement ceased. Starting with the peak of solar cycle 21, there was good general agreement of Ipe EUV with the 10.7 cm, Ca K, and He 10830 solar indices, until the onset of solar cycle 22. From 1989 to the start of 1992, the 10.7 cm flux exhibited a broad maximum consisting of two peaks of nearly equal magnitude, whereas Ipe EUV exhibited a strong increase during this time period making the second peak significantly higher than the first. The only solar index that exhibits the same increase in solar activity as Ipe EUV and L-alpha during the cycle 22 peak is the total magnetic flux. The case for high activity during this peak is also supported by the presence of very high solar flare intensity.

  20. Relationships between solar activity and climate change

    NASA Technical Reports Server (NTRS)

    Roberts, W. O.

    1975-01-01

    The relationship between recurrent droughts in the High Plains of the United States and the double sunspot cycle is discussed in detail. It is suggested that high solar activity is generally related to an increase in meridional circulation and blocking patterns at high and intermediate latitudes, especially in winter, and the effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

  1. Sources of the solar wind at solar activity maximum

    NASA Astrophysics Data System (ADS)

    Neugebauer, M.; Liewer, P. C.; Smith, E. J.; Skoug, R. M.; Zurbuchen, T. H.

    2002-12-01

    The photospheric sources of solar wind observed by the Ulysses and ACE spacecraft from 1998 to early 2001 are determined through a two-step mapping process. Solar wind speed measured at the spacecraft is used in a ballistic model to determine a foot point on a source surface at a solar distance of 2.5 solar radii. A potential-field source-surface model is then used to trace the field and flow from the source surface to the photosphere. Comparison of the polarity of the measured interplanetary field with the polarity of the photospheric source region shows good agreement for spacecraft latitudes equatorward of 60°. At higher southern latitudes, the mapping predicts that Ulysses should have observed only outward directed magnetic fields, whereas both polarities were observed. A detailed analysis is performed on four of the solar rotations for which the mapped and observed polarities were in generally good agreement. For those rotations, the solar wind mapped to both coronal holes and active regions. These findings for a period of high solar activity differ from the findings of a similar study of the solar wind in 1994-1995 when solar activity was very low. At solar minimum the fastest wind mapped to the interior of large polar coronal holes while slower wind mapped to the boundaries of those holes or to smaller low-latitude coronal holes. For the data examined in the present study, neither spacecraft detected wind from the small polar coronal holes when they existed and the speed was never as high as that observed by Ulysses at solar minimum. The principal difference between the solar wind from coronal holes and from active regions is that the O7+/O6+ ion ratio is lower for the coronal hole flow, but not as low as in the polar coronal hole flow at solar minimum. Furthermore, the active-region flows appear to be organized into several substreams unlike the more monolithic structure of flows from coronal holes. The boundaries between plasma flows from neighboring

  2. Monitoring Variations to the Near-Earth Space Environment during High Solar Activity Using Orbiting Rocket Bodies

    NASA Astrophysics Data System (ADS)

    Romero, V.; Ryan, W.; Ryan, E.

    A space object's general characteristics can be substantially influenced by changes in the magnetosphere, ionosphere, and thermosphere environments. These space weather effects can vary according to the space object's orbit, position relative to certain regions in space, the severity of solar activity, and many other factors. Outcomes can range from minor and easily recoverable to total breakdown. Further, technology has advanced such that satellite components have become smaller and smaller, and these micro-systems are increasingly more susceptible to the highly energetic solar particles associated with intense activity. Therefore, additional study of the significance of space weather events on Earth-orbiting objects would be beneficial. A rotating rocket body in orbit experiences a magnetic torque due to the Earth's magnetic field that results in an exponential decay of its rotational frequency and a variation on the axis of rotation. The Photometric Periods of Artificial Satellites (McCants, 2007) database consists of over 60,000 period measurements, mostly visually acquired, dating back to 1958. Although this database validates this predicted exponential decay in rotation rate, many anomalies have been observed, including increased rotational frequencies. Theories for the causes of these anomalies range from leaking fuel tanks to interaction with the local space environment. Our program aims to complement the current visual database through CCD and video photometric observations of rotating rocket bodies using a portable 0.35-meter telescope and the Magdalena Ridge Observatory's 2.4-meter telescope. The goal is to generate a detailed astrometric and photometric database for a small set of targets at different orbital altitudes in order to study the variability in orbital motion and the rotational angular momentum vector, particularly during times of high solar activity. The National Oceanic and Atmospheric Administration (NOAA) provides daily information and

  3. High Voltage Space Solar Arrays

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.; Vayner, B. V.; Galofaro, J. T.; Lyons, Valerie (Technical Monitor)

    2002-01-01

    Recent tests performed at the NASA Glenn Research Center and elsewhere have shown promise in the design and construction of high voltage (300-1000 V) solar arrays for space applications. Preliminary results and implications for solar array design will be discussed, with application to direct-drive electric propulsion and space solar power.

  4. Solar activity secular cycles

    NASA Astrophysics Data System (ADS)

    Kramynin, A. P.; Mordvinov, A. V.

    2013-12-01

    Long-term variations in solar activity secular cycles have been studied using a method for the expansion of reconstructed sunspot number series Sn( t) for 11400 years in terms of natural orthogonal functions. It has been established that three expansion components describe more than 98% of all Sn( t) variations. In this case, the contribution of the first expansion component is about 92%. The averaged form of the 88year secular cycle has been determined based on the form of the first expansion coordinate function. The quasi-periodicities modulating the secular cycle have been revealed based on the time function conjugate to the first function. The quasi-periodicities modulating the secular cycle coincide with those observed in the Sn( t) series spectrum. A change in the secular cycle form and the time variations in this form are described by the second and third expansion components, the contributions of which are about 4 and 2%, respectively. The variations in the steepness of the secular cycle branches are more pronounced in the 200-year cycle, and the secular cycle amplitude varies more evidently in the 2300-year cycle.

  5. Very high efficiency solar cells

    NASA Astrophysics Data System (ADS)

    Barnett, Allen; Kirkpatrick, Douglas; Honsberg, Christiana

    2006-08-01

    The Defense Advanced Research Projects Agency has initiated the Very High Efficiency Solar Cell (VHESC) program to address the critical need of the soldier for power in the field. Very High Efficiency Solar Cells for portable applications that operate at greater than 55 percent efficiency in the laboratory and 50 percent in production are being developed. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space that leads to a new architecture paradigm. An integrated team effort is now underway that requires us to invent, develop and transfer to production these new solar cells. Our approach is driven by proven quantitative models for the solar cell design, the optical design and the integration of these designs. We start with a very high performance crystalline silicon solar cell platform. Examples will be presented. Initial solar cell device results are shown for devices fabricated in geometries designed for this VHESC Program.

  6. A multi-stacked hyperporous silicon flake for highly active solar hydrogen production.

    PubMed

    Jang, Youn Jeong; Ryu, Jaegeon; Hong, Dongki; Park, Soojin; Lee, Jae Sung

    2016-08-11

    3D multi-stacked hyperporous silicon flakes (MHSFs) are prepared via a selective chemical reduction of natural clay minerals bearing MgO negative catalyst layers. The resultant MHSFs are used as a photocatalyst for solar-driven hydrogen evolution and exhibit the highest photocatalytic acitivty (1031 μmol H2 h(-1) g(-1) Si) coupled with a Pt cocatalyst. PMID:27383444

  7. A Graphene Composite Material with Single Cobalt Active Sites: A Highly Efficient Counter Electrode for Dye-Sensitized Solar Cells.

    PubMed

    Cui, Xiaoju; Xiao, Jianping; Wu, Yihui; Du, Peipei; Si, Rui; Yang, Huaixin; Tian, Huanfang; Li, Jianqi; Zhang, Wen-Hua; Deng, Dehui; Bao, Xinhe

    2016-06-01

    The design of catalysts that are both highly active and stable is always challenging. Herein, we report that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs). A series of composite materials based on different metals (Mn, Fe, Co, Ni, and Cu) were synthesized and characterized. Electrochemical measurements revealed that CoN4 /GN is a highly active and stable counter electrode for the interconversion of the redox couple I(-) /I3 (-) . DFT calculations revealed that the superior properties of CoN4 /GN are due to the appropriate adsorption energy of iodine on the confined Co sites, leading to a good balance between adsorption and desorption processes. Its superior electrochemical performance was further confirmed by fabricating DSSCs with CoN4  /GN electrodes, which displayed a better power conversion efficiency than the Pt counterpart. PMID:27089044

  8. Solar activity and the weather

    NASA Technical Reports Server (NTRS)

    Wilcox, J. M.

    1975-01-01

    The attempts during the past century to establish a connection between solar activity and the weather are discussed; some critical remarks about the quality of much of the literature in this field are given. Several recent investigations are summarized. Use of the solar/interplanetary magnetic sector structure in future investigations is suggested to add an element of cohesiveness and interaction to these investigations.

  9. Solar activity and myocardial infarction.

    PubMed

    Szczeklik, E; Mergentaler, J; Kotlarek-Haus, S; Kuliszkiewicz-Janus, M; Kucharczyk, J; Janus, W

    1983-01-01

    The correlation between the incidence of myocardial infarction, sudden cardiac death, the solar activity and geomagnetism in the period 1969-1976 was studied, basing on Wrocław hospitals material registered according to WHO standards; sudden death was assumed when a person died within 24 hours after the onset of the disease. The highest number of infarctions and sudden deaths was detected for 1975, which coincided with the lowest solar activity, and the lowest one for the years 1969-1970 coinciding with the highest solar activity. Such an inverse, statistically significant correlation was not found to exist between the studied biological phenomena and geomagnetism. PMID:6851574

  10. Low Latitude Aurora: Index of Solar Activity

    NASA Astrophysics Data System (ADS)

    Bekli, M. R.; Aissani, D.; Chadou, I.

    2010-10-01

    Observations of aurora borealis at low latitudes are rare, and are clearly associated with high solar activity. In this paper, we analyze some details of the solar activity during the years 1769-1792. Moreover, we describe in detail three low latitude auroras. The first event was reported by ash-Shalati and observed in North Africa (1770 AD). The second and third events were reported by l'Abbé Mann and observed in Europe (1770 and 1777 AD).

  11. Solar activity over different timescales

    NASA Astrophysics Data System (ADS)

    Obridko, Vladimir; Nagovitsyn, Yuri

    The report deals with the “General History of the Sun” (multi-scale description of the long-term behavior of solar activity): the possibility of reconstruction. Time scales: • 100-150 years - the Solar Service. • 400 - instrumental observations. • 1000-2000 years - indirect data (polar auroras, sunspots seen with the naked eye). • Over-millennial scale (Holocene) -14С (10Be) Overview and comparison of data sets. General approaches to the problem of reconstruction of solar activity indices on a large timescale. North-South asymmetry of the sunspot formation activity. 200-year cycle over the “evolution timescales”.The relative contribution of the large-scale and low-latitude. components of the solar magnetic field to the general geomagnetic activity. “Large-scale” and low-latitude sources of geomagnetic disturbances.

  12. New NSO Solar Surface Activity Maps

    NASA Astrophysics Data System (ADS)

    Henney, C. J.; Harvey, J. W.

    2001-05-01

    Using NSO-Kitt Peak Vacuum Telescope (KPVT) synoptic data, we present several new solar surface activity maps. The motivation is to test conventional wisdom about conditions that are likely to produce solar activity such as flares, coronal mass ejections and high speed solar wind streams. The ultimate goal is to improve real-time, observation-based models for the purpose of predicting solar activity. A large number of maps will eventually be produced based on the wide range of ideas and models of the conditions thought to lead to solar activity events. When data from the new SOLIS instruments becomes available, the range of possible models that can be tested will be greatly expanded. At present, the daily maps include ones that show magnetic field complexity, emerging flux and high speed solar wind sources. As a proxy for local magnetic potential energy, each element of the magnetic complexity map is the distance-weighted rms of the opposing ambient magnetic field. The flux emergence map is the difference between the two most recent absolute magnetic flux images. The solar wind source map is produced from coronal hole area data. The new maps are available on the NSO-Kitt Peak World Wide Web page. This research was supported in part by the Office of Navel Research Grant N00014-91-J-1040. The NSO-Kitt Peak data used here are produced cooperatively by NSF/AURA, NASA/GSFC, and NOAA/SEC.

  13. Carbon cycle dynamics and solar activity embedded in a high-resolution 14C speleothem record from Belize, Central America

    NASA Astrophysics Data System (ADS)

    Lechleitner, Franziska A.; Breitenbach, Sebastian F. M.; McIntyre, Cameron; Asmerom, Yemane; Prufer, Keith M.; Polyak, Victor; Culleton, Brendan J.; Kennett, Douglas J.; Eglinton, Timothy I.; Baldini, James U. L.

    2015-04-01

    Speleothem 14C has recently emerged as a potentially powerful proxy for climate reconstruction. Several studies have highlighted the link between karst hydrology and speleothem 14C content, and a number of possible causes for this relationship have been proposed, such as dripwater flow dynamics in the karst and changes in soil organic matter (SOM) turnover time (e.g. Griffiths et al., 2012). Here we present a high resolution 14C record for a stalagmite (YOK-I) from Yok Balum cave in southern Belize, Central America. YOK-I grew continuously over the last 2000 years, and has been dated very precisely with the U-Th method (40 dates, mean uncertainty < 10 years). The excellent chronological control for this stalagmite allows us to calculate 14C activity (a14C) at the time of speleothem deposition (a14Cinit), as well as the dead carbon fraction (DCF), predominantly a measure of the reservoir effect introduced by limestone dissolution in the karst (Genty et al., 2001). Both records show striking similarities to atmospheric a14C (IntCal13) and reconstructions of solar activity and 14C production rate. We infer close coupling between cave environment and atmosphere, with minimal signal dampening, an observation supported by monitoring data (Ridley et al., in press). DCF fluctuates between approximately 10% and 16% over the entire record, with distinctly lower DCF values and higher a14Cinit during a period of reduced rainfall between ca. 700-1100 AD (linked to the Classic Maya Collapse). This behavior is consistent with observations made elsewhere, and suggests that DCF responds to karst hydrological variability, specifically open-closed system transitions. YOK-I a14Cinit typically lags atmospheric values by 10-100 cal years. A shorter lag appears to be linked to periods of drought, suggesting a response of SOM dynamics above the cave to rainfall reduction. Specifically, drought is inferred to lead to reduced bioproductivity and soil carbon turnover, lowering contributions

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

    NASA Astrophysics Data System (ADS)

    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.

  15. High temperature solar thermal technology

    NASA Technical Reports Server (NTRS)

    Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

    1980-01-01

    Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

  16. Ternary Blend Composed of Two Organic Donors and One Acceptor for Active Layer of High-Performance Organic Solar Cells.

    PubMed

    Lee, Jong Won; Choi, Yoon Suk; Ahn, Hyungju; Jo, Won Ho

    2016-05-01

    Ternary blends composed of two donor absorbers with complementary absorptions provide an opportunity to enhance the short-circuit current and thus the power conversion efficiency (PCE) of organic solar cells. In addition to complementary absorption of two donors, ternary blends may exhibit favorable morphology for high-performance solar cells when one chooses properly the donor pair. For this purpose, we develop a ternary blend with two donors (diketopyrrolopyrrole-based polymer (PTDPP2T) and small molecule ((TDPP)2Ph)) and one acceptor (PC71BM). The solar cell made of a ternary blend with 10 wt % (TDPP)2Ph exhibits higher PCE of 7.49% as compared with the solar cells with binary blends, PTDPP2T:PC71BM (6.58%) and (TDPP)2Ph:PC71BM (3.21%). The higher PCE of the ternary blend solar cell is attributed mainly to complementary absorption of two donors. However, a further increase in (TDPP)2Ph content in the ternary blend (>10 wt %) decreases the PCE. The ternary blend with 10 wt % (TDPP)2Ph exhibits well-developed morphology with narrow-sized fibrils while the blend with 15 wt % (TDPP)2Ph shows phase separation with large-sized domains, demonstrating that the phase morphology and compatibility of ternary blend are important factors to achieve a high-performance solar cell made of ternary blends. PMID:27067461

  17. TEC prediction performance of IRI-2012 model during a very low and a high solar activity phase over equatorial regions, Uganda

    NASA Astrophysics Data System (ADS)

    Tariku, Yekoye Asmare

    2015-07-01

    This paper examines the capacity of the latest version of the International Reference Ionosphere (IRI-2012) model in predicting the vertical total electron content (VTEC) variation over Uganda during a very low solar activity phase (2009) and a high solar activity (2012) phase. This has been carried out by comparing the ground-based Global Positioning System (GPS) VTEC inferred from dual-frequency GPS receivers installed at Entebbe (geographic latitude 0.038°N and longitude 32.44°E; geomagnetic latitude -9.53°N and longitude 104.06°E) and Mbarara (geographic latitude -0.60°N and longitude 30.74°E; geomagnetic latitude -10.02°N and longitude 102.36°E). In this work, the diurnal, monthly, and seasonal variations in the measured VTEC have been analyzed and compared with the VTEC derived from IRI-2012 model. It has been shown that the lowest diurnal peak GPS-VTEC values are observed in the June solstice months during both the low and the high solar activity phases. Similarly, the highest diurnal peak IRI-2012 VTEC values are observed in equinoctial months during both phases. The variability of the VTEC in both the experimental and model is minimal nearly at 03:00 UT (06:00 LT) and maximal mostly between 10:00 and 13:00 UT (13:00-16:00 LT) during both phases. The diurnal highest peak modeled VTEC value observed during the high solar activity phase is almost twice larger than the diurnal highest peak modeled VTEC value depicted during the low solar activity phase. Moreover, the highest monthly mean hourly measured VTEC value observed in October during the high solar activity phase is larger by more than twice the corresponding highest monthly mean hourly measured VTEC value observed in November during the low solar activity phase. Similarly, the lowest monthly measured VTEC value observed in July during the high solar activity phase is larger by more than twice the corresponding lowest measured monthly VTEC value observed in the same month during the low solar

  18. A solar high temperature kiln

    NASA Astrophysics Data System (ADS)

    Huettenhoelscher, N.; Bergmann, K.

    1981-11-01

    The feasibility of using solar energy in developing countries for baking ceramic construction materials was investigated. The solar high temperature kiln is described. It uses two parabolic concentrators which direct available radiation into the baking chamber. The Sun tracker has only one axis. Preliminary test results with the prototype kiln were satisfactory.

  19. High Radiation Resistance IMM Solar Cell

    NASA Technical Reports Server (NTRS)

    Pan, Noren

    2015-01-01

    Due to high launch costs, weight reduction is a key driver for the development of new solar cell technologies suitable for space applications. This project is developing a unique triple-junction inverted metamorphic multijunction (IMM) technology that enables the manufacture of very lightweight, low-cost InGaAsP-based multijunction solar cells. This IMM technology consists of indium (In) and phosphorous (P) solar cell active materials, which are designed to improve the radiation-resistant properties of the triple-junction solar cell while maintaining high efficiency. The intrinsic radiation hardness of InP materials makes them of great interest for building solar cells suitable for deployment in harsh radiation environments, such as medium Earth orbit and missions to the outer planets. NASA Glenn's recently developed epitaxial lift-off (ELO) process also will be applied to this new structure, which will enable the fabrication of the IMM structure without the substrate.

  20. Statistical Properties of Extreme Solar Activity Intervals

    NASA Astrophysics Data System (ADS)

    Lioznova, A. V.; Blinov, A. V.

    2014-01-01

    A study of long-term solar variability reflected in indirect indices of past solar activity leads to stimulating results. We compare the statistics of intervals of very low and very high solar activity derived from two cosmogenic radionuclide records and look for consistency in their timing and physical interpretation. According to the applied criteria, the numbers of minima and of maxima are 61 and 68, respectively, from the 10Be record, and 42 and 46 from the 14C record. The difference between the enhanced and depressed states of solar activity becomes apparent in the difference in their statistical distributions. We find no correlation between the level or type (minimum or maximum) of an extremum and the level or type of the predecessor. The hypothesis of solar activity as a periodic process on the millennial time scale is not supported by the existing proxies. A new homogeneous series of 10Be measurements in polar ice covering the Holocene would be of great value for eliminating the existing discrepancy in the available solar activity reconstructions.

  1. Sources of solar wind over the solar activity cycle.

    PubMed

    Poletto, Giannina

    2013-05-01

    Fast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review. PMID:25685421

  2. High efficiency solar cell research for space applications

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1985-01-01

    A review is given of NASA photovoltaic research with emphasis on the activities of the Lewis Research Center. High efficiency solar cell research is discussed, as well as solar arrays, multi-junction cell bandgaps, and plasmon coupling.

  3. Solar collector manufacturing activity, 1988

    NASA Astrophysics Data System (ADS)

    1989-11-01

    This report was prepared by the Energy Information Administration, the independent statistical and analytical agency within the U.S. Department of Energy in cooperation with the Office of Conservation and Renewable Energy. The report presents data on producer shipments and end uses obtained from manufacturers and importers of solar thermal collectors and photovoltaic modules. It provides annual data necessary for the Department of Energy to execute its responsibility to: (1) monitor activities and trends in the solar collector manufacturing industry, (2) prepare the national energy strategy, and (3) provide information on the size and status of the industry to interested groups such as the U.S. Congress, government agencies, the Solar Energy Research institute, solar energy specialists, manufacturers, and the general public.

  4. High flux solar energy transformation

    DOEpatents

    Winston, Roland; Gleckman, Philip L.; O'Gallagher, Joseph J.

    1991-04-09

    Disclosed are multi-stage systems for high flux transformation of solar energy allowing for uniform solar intensification by a factor of 60,000 suns or more. Preferred systems employ a focusing mirror as a primary concentrative device and a non-imaging concentrator as a secondary concentrative device with concentrative capacities of primary and secondary stages selected to provide for net solar flux intensification of greater than 2000 over 95 percent of the concentration area. Systems of the invention are readily applied as energy sources for laser pumping and in other photothermal energy utilization processes.

  5. High flux solar energy transformation

    DOEpatents

    Winston, R.; Gleckman, P.L.; O'Gallagher, J.J.

    1991-04-09

    Disclosed are multi-stage systems for high flux transformation of solar energy allowing for uniform solar intensification by a factor of 60,000 suns or more. Preferred systems employ a focusing mirror as a primary concentrative device and a non-imaging concentrator as a secondary concentrative device with concentrative capacities of primary and secondary stages selected to provide for net solar flux intensification of greater than 2000 over 95 percent of the concentration area. Systems of the invention are readily applied as energy sources for laser pumping and in other photothermal energy utilization processes. 7 figures.

  6. Solar Energy Project, Activities: Biology.

    ERIC Educational Resources Information Center

    Tullock, Bruce, Ed.; And Others

    This guide contains lesson plans and outlines of science activities which present concepts of solar energy in the context of biology experiments. Each unit presents an introduction; objectives; skills and knowledge needed; materials; methods; questions; recommendations for further work; and a teacher information sheet. The teacher information…

  7. TEC variability over Havana for different solar activity conditions

    NASA Astrophysics Data System (ADS)

    Lazo, B.; Alazo, K.; Rodríguez, M.; Calzadilla, A.

    2004-01-01

    The variability of total electron content measured over Havana using ATS-6, SMS-1 and GOES-3 geosynchronous satellite signals has been investigated for low, middle and high solar activity periods from 1974 to 1982. The results show that the standard deviation is smooth during the nighttime hours and maximal at the noon or postnoon hours. A strong solar activity dependence of the standard deviation has been found with maximum values during periods of high solar activity.

  8. High Efficiency Cascade Solar Cells

    SciTech Connect

    Shuguang Deng, Seamus Curran, Igor Vasiliev

    2010-09-28

    This report summarizes the main work performed by New Mexico State University and University of Houston on a DOE sponsored project High Efficiency Cascade Solar Cells. The main tasks of this project include materials synthesis, characterization, theoretical calculations, organic solar cell device fabrication and test. The objective of this project is to develop organic nano-electronic-based photovoltaics. Carbon nanotubes and organic conjugated polymers were used to synthesize nanocomposites as the new active semiconductor materials that were used for fabricating two device architectures: thin film coating and cascade solar cell fiber. Chemical vapor deposition technique was employed to synthesized a variety of carbon nanotubes (single-walled CNT, doubled-walled CNT, multi-walled CNT, N-doped SWCNT, DWCNT and MWCNT, and B-doped SWCNT, DWCNT and MWCNT) and a few novel carbon structures (CNT-based nanolance, nanocross and supported graphene film) that have potential applications in organic solar cells. Purification procedures were developed for removing amorphous carbons from carbon nanotubes, and a controlled oxidation method was established for partial truncation of fullerene molecules. Carbon nanotubes (DWCNT and DWCNT) were functionalized with fullerenes and dyes covalently and used to form nanocomposites with conjugated polymers. Biologically synthesized Tellurium nanotubes were used to form composite with the conjugated polymers as well, which generated the highest reported optical limiting values from composites. Several materials characterization technique including SEM/TEM, Raman, AFM, UV-vis, adsorption and EDS were employed to characterize the physical and chemical properties of the carbon nanotubes, the functionalized carbon nanotubes and the nanocomposites synthesized in this project. These techniques allowed us to have a spectroscopic and morphological control of the composite formation and to understand the materials assembled. A parallel 136-CPU

  9. High voltage solar array experiments

    NASA Technical Reports Server (NTRS)

    Kennerud, K. L.

    1974-01-01

    The interaction between the components of a high voltage solar array and a simulated space plasma is studied to obtain data for the design of a high voltage solar array capable of 15kW at 2 to 16kV. Testing was conducted in a vacuum chamber 1.5-m long by 1.5-m diameter having a plasma source which simulated the plasma conditions existing in earth orbit between 400 nautical miles and synchronous altitude. Test samples included solar array segments pinholes in insulation covering high voltage electrodes, and plain dielectric samples. Quantitative data are presented in the areas of plasma power losses, plasma and high voltage induced damage, and dielectric properties. Limitations of the investigation are described.

  10. Highly Alfvenic Slow Solar Wind

    NASA Technical Reports Server (NTRS)

    Roberts, D. Aaron

    2010-01-01

    It is commonly thought that fast solar wind tends to be highly Alfvenic, with strong correlations between velocity and magnetic fluctuations, but examples have been known for over 20 years in which slow wind is both Alfvenic and has many other properties more typically expected of fast solar wind. This paper will present a search for examples of such flows from more recent data, and will begin to characterize the general characteristics of them. A very preliminary search suggests that such intervals are more common in the rising phase of the solar cycle. These intervals are important for providing constraints on models of solar wind acceleration, and in particular the role waves might or might not play in that process.

  11. Development of single and micromorph tandem solar cells in n-i-p configuration with high-pressure RF-PECVD deposited doped and active layers

    NASA Astrophysics Data System (ADS)

    Hou, Guofu; Xue, Junming; Yuan, Yujie; Yang, Xingyun; Liu, Yunzhou; Zhao, Ying; Geng, Xinhua

    2008-03-01

    This paper gives an overview of the scientific challenges and achievements during the development of thin film silicon based single and tandem solar cells with high-pressure RF-PECVD deposited doped and active layers. The effect of i/p interface treatment on the crystalline growth of high conductive p-type layer and the improvement of the Voc and FF of single-junction a-Si:H solar cell was studied. The role of gradient hydrogen dilution technique in the controlling the microstructural evolution of the intrinsic layer and its influence on the solar cell performance were investigated. By combining above methods, an efficiency of 5.7% (Voc=470mV, Jsc=20.2mA/cm2, FF=60%) has been for a single-junction μc-Si:H solar cell. Then, the thicknesses of bottom cells and top cells were varied to achieve good current matching, which yield an efficiency of 9.9% for μc-Si:H/a-Si:H tandem solar cell with Voc of 1221mV, Jsc of 11.61mA/cm2 and fill factor of 70%.

  12. Solar wind turbulence as a driver of geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Ikechukwu Ugwu, Ernest Benjamin; Nneka Okeke, Francisca; Ugonabo, Obiageli Josephine

    2016-07-01

    We carried out simultaneous analyses of interplanetary and geomagnetic datasets for the period of (solar Maunder) least (2009) and maximum (2002) solar activity to determine the nature of solar wind turbulence on geomagnetic activity using AE, ASY-D, and ASY-H indices. We determined the role played by Alfvénic fluctuations in the solar wind so as to find out the nature of the turbulence. Our analyses showed that solar wind turbulence play a role in geomagnetic processes at high latitudes during periods of low and high solaractivity but does not have any effect at mid-low latitudes.

  13. Colloidal synthesis of wurtz-stannite Cu2CdGeS4 nanocrystals with high catalytic activity toward iodine redox couples in dye-sensitized solar cells.

    PubMed

    Huang, Shoushuang; Zai, Jiantao; Ma, Dui; He, Qingquan; Liu, Yuanyuan; Qiao, Qiquan; Qian, Xuefeng

    2016-09-18

    Wurtz-stannite Cu2CdGeS4 nanocrystals were synthesized via a facile hot-injection method at a low temperature. They exhibited low charge transfer resistance at the electrolyte-electrode interface and high electrocatalytic activity for the reduction of I3(-) in dye-sensitized solar cells (DSSCs). Moreover, this DSSC showed a power conversion efficiency of 7.67%, comparable to the Pt-based device (7.54%). PMID:27524660

  14. Preparation of N-doped ZnO-loaded halloysite nanotubes catalysts with high solar-light photocatalytic activity.

    PubMed

    Cheng, Zhi-Lin; Sun, Wei

    2015-01-01

    N-doped ZnO nanoparticles were successfully assembled into hollow halloysite nanotubes (HNTs) by using the impregnation method. The catalysts based on N-doped ZnO-loaded HNTs nanocomposites (N-doped ZnO/HNTs) were characterized by X-ray diffraction (XRD), transmission electron microscopy-energy dispersive X-ray (TEM-EDX), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), UV-vis and Fourier transform infrared spectroscopy (FT-IR) techniques. The XRD pattern showed ZnO nanoparticles with hexagonal structure loaded on HNTs. The TEM-EDX analysis indicated ZnO particles with the crystal size of ca.10 nm scattered in hollow structure of HNTs, and furthermore the concentration of N atom in nanocomposites was up to 2.31%. The SEM-EDX verified most of N-ZnO nanoparticles existing in hollow nanotubes of HNTs. Besides containing an obvious ultraviolet absorbance band, the UV-vis spectra of the N-doped ZnO/HNTs catalysts showed an available visible absorbance band by comparing to HNTs and non-doped ZnO/HNTs. The photocatalytic activity of the N-doped ZnO/HNTs catalysts was evaluated by the degradation of methyl orange (MO) solution with the concentration of 20 mg/L under the simulated solar-light irradiation. The result showed that the N-doped ZnO/HNTs catalyst exhibited a desirable solar-light photocatalytic activity. PMID:26540544

  15. High Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

  16. Module greenhouse with high efficiency of transformation of solar energy, utilizing active and passive glass optical rasters

    SciTech Connect

    Korecko, J.; Jirka, V.; Sourek, B.; Cerveny, J.

    2010-10-15

    Since the eighties of the 20th century, various types of linear glass rasters for architectural usage have been developed in the Czech Republic made by the continuous melting technology. The development was focused on two main groups of rasters - active rasters with linear Fresnel lenses in fixed installation and with movable photo-thermal and/or photo-thermal/photo-voltaic absorbers. The second group are passive rasters based on total reflection of rays on an optical prism. During the last years we have been working on their standardization, exact measuring of their optical and thermal-technical characteristics and on creation of a final product that could be applied in solar architecture. With the project supported by the Ministry of Environment of the Czech Republic we were able to build an experimental greenhouse using these active and passive optical glass rasters. The project followed the growing number of technical objectives. The concept of the greenhouse consisted of interdependence construction - structural design of the greenhouse with its technological equipment securing the required temperature and humidity conditions in the interior of the greenhouse. This article aims to show the merits of the proposed scheme and presents the results of the mathematical model in the TRNSYS environment through which we could predict the future energy balance carried out similar works, thus optimizing the investment and operating costs. In this article description of various technology applications for passive and active utilization of solar radiation is presented, as well as some results of short-term and long-term experiments, including evaluation of 1-year operation of the greenhouse from the energy and interior temperature viewpoints. A comparison of the calculated energy flows in the greenhouse to real measured values, for verification of the installed model is also involved. (author)

  17. Influence of solar activity on climate change

    NASA Astrophysics Data System (ADS)

    Kirichenko, Kirill; Kovalenko, Vladimir

    The questions of primary importance for understanding the nature of climate changes in the XX century and main physical processes responsible for these changes are discussed. A physical model of the influence of solar activity on climate characteristics is presented. A key concept of this model is the influence of heliogeophysical disturbances on the Earth's climate system parameters controlling the long-wave radiation flux going out into space in high-latitude regions. A change in the Earth's radiation balance of high-latitude regions induces restructuring of the tropospheric thermobaric field, changes in the meridional temperature gradient responsible for meridional heat transfer. This causes changes in the heat content of the Earth's climate system and global climate. We present and discuss results of analysis of regularities and peculiarities of tropospheric and sea surface temperature (SST) responses both to separate heliogeophysical disturbances and to long-term changes of solar and geomagnetic activity. It is established that the climatic response in the tropospheric and sea surface temperature to the effect of solar and geomagnetic activity is characterised by a significant space-time irregularity and is local. A distinguishing feature of these distributions is the presence of regions of both positive and negative correlations. The exception is the epoch (1910-1940) when the SST response to geomagnetic activity was positive in virtually all regions, i. e. was global. This epoch coincides with the longest period of increase in geomagnetic activity during the period considered at the end of which annual averages of geomagnetic activity exceeded maximum values at the beginning of the epoch. Key words: climate, ocean, troposphere, solar activity.

  18. Mars' upper atmosphere and ionosphere at low, medium, and high solar activities: Implications for evolution of water

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2002-12-01

    Self-consistent models for 11 neutral and 18 ion species from 80 to 300 km on Mars have been developed by solving the continuity equations including ambipolar diffusion for ions. The models were calculated for the conditions of the HST, FUSE, and Mariner 6 and 7 observations of D, H2, and H, respectively, when the solar activity index was equal to 25, 61, and 88 at Mars orbit, respectively. Special care was taken to simulate the processes of H2 and HD dissociation in the reactions with CO2+, O+, CO+, N2+, N+, Ar+, and O(1D) and by photoelectrons. Thermal and nonthermal escape velocities were used as the upper boundary conditions for H2, H, HD, D, and He. The H2 and HD mixing ratios of 15 ppm and 11 ppb chosen to fit the FUSE and HST observations of H2 and D, respectively, result in (HD/H2)/(HDO/H2O) = 0.4. This value agrees with the depletion of D in H2 because of the smaller HDO photolysis cross section and the preferential condensation of HDO above the condensation level. Therefore the controversial problem of deuterium fractionation is solved throughout the atmosphere. The influx of cometary water was ~0.5 m planetwide in the last 3.8 billion years. It cannot affect the estimates of more than 30 m of water lost by sputtering and nonthermal and thermal escape and more than 1.3 km of water lost in the reaction with iron with subsequent hydrodynamic escape of H2. The calculated ion density profiles at various solar activity and the column reaction rates provide complete quantitative information for behavior of each ion, its formation, and its loss. The HCO+ ion is abundant in Mars' ionosphere because it is a final product of many reactions of other ions with H2 and does not react with neutral species.

  19. Solar absorber material stability under high solar flux

    NASA Astrophysics Data System (ADS)

    Ignatiev, A.; Zajac, G.; Smith, G. B.

    1982-04-01

    Solar absorbing Black Chrome coatings have been exposed to high temperatures (350-400 C) under high solar fluxes (0.4 to 2.0 MW/sq m) to test for their stability under actual operating conditions. Field tests at the White Sands Solar Furnace have shown higher stability than expected from oven tested samples. Laboratory studies utilizing spectrally selective concentrated solar simulated radiation have indicated that the cause of the higher stability under solar irradiation is photo-stimulated desorption of oxygen bearing species at the absorber surface and resultant reduced oxidation of the absorber.

  20. The Heliosphere Through the Solar Activity Cycle

    NASA Technical Reports Server (NTRS)

    Balogh, A.; Lanzerotti, L. J.; Suess, S. T.

    2006-01-01

    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 describe the rise in solar ESA and NASA have now unamiously agreed a third extension to operate the highly successful Ulysses spacecraft until March 2008 and, in 2007 and 2008, the European-built space probe will fly over the poles of the Sun for a third time. This will enable Ulysses to add an important chapter to its survey of the high-latitude heliosphere and this additional material would be included in a 2nd edition of this book.

  1. Initiation of non-tropical thunderstorms by solar activity

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Goldberg, R. A.

    1978-01-01

    A theory of thunderstorm initiation is proposed to account for the statistical correlation between solar activity and thunderstorm occurrence in middle to high latitudes. It is suggested that cosmic ray decreases and/or high-energy solar protons associated with active solar events enhance the electric field at low heights so that, if appropriate meteorological conditions are present during a solar event, the atmospheric electric field enhancement may be sufficient to trigger thunderstorm development. Statistical correlations and atmospheric electric effects are described. The theory could be tested if the possible forcing functions and the responding atmospheric electrical and ionic species' characteristics were measured.

  2. High temperature solar thermal receiver

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A design concept for a high temperature solar thermal receiver to operate at 3 atmospheres pressure and 2500 F outlet was developed. The performance and complexity of windowed matrix, tube-header, and extended surface receivers were evaluated. The windowed matrix receiver proved to offer substantial cost and performance benefits. An efficient and cost effective hardware design was evaluated for a receiver which can be readily interfaced to fuel and chemical processes or to heat engines for power generation.

  3. Solar activities observed with the New Vacuum Solar Telescope

    NASA Astrophysics Data System (ADS)

    Yang, Shuhong

    2015-08-01

    The New Vacuum Solar Telescope is the most important facility of the Fuxian Solar Observatory in China. Based on the high spatial and temporal resolution NVST observations, we investigate the solar activities in the chromosphere and obtain some new results. (1) Observations of a flux rope tracked by filament activation (Yang et al. 2014a). The filament material is initially located at one end of the flux rope and fills in a section of the rope. Then the filament is activated and the material flows along helical threads, tracking the twisted flux rope structure. The flux rope can be detected in both low temperature and high temperature lines, and there exists a striking anti-correlation between the Hα and EUV lines, which could imply some mild heating of cool filament material to coronal temperatures during the filament activation. (2) Fine structures and overlying loops of homologous confined solar flares (Yang et al. 2014b). At the pre-flare stage, there exists a reconnection between small loops. During the flare processes, the overlying loops, some of which are tracked by activated dark materials, do not break out. These direct observations may illustrate the physical mechanism of confined flares, i.e., magnetic reconnection between the emerging loops and the pre-existing loops triggers flares and the overlying loops prevent the flares from being eruptive. (3) Magnetic reconnection between small-scale loops (Yang et al. 2015). We report the solid observational evidence of magnetic reconnection between two sets of small-scale loops. The observed signatures are consistent with the predictions by reconnection models. The thickness and length of the current sheet are determined to be about 420 km and 1.4 Mm, respectively. The reconnection process contains a slow step and a rapid step. We suggest that the successive slow reconnection changes the conditions around the reconnection site and disrupts the instability, thus leading to the rapid approach of the anti

  4. Recurrence of solar activity - Evidence for active longitudes

    NASA Technical Reports Server (NTRS)

    Bogart, R. S.

    1982-01-01

    It is pointed out that the autocorrelation coefficients of the daily Wolf sunspot numbers over a period of 128 years reveal a number of interesting features of the variability of solar activity. Besides establishing periodicities for the solar rotation, solar activity cycle, and, perhaps, the 'Gleissberg Cycle', they suggest that active longitudes do exist, but with much greater strength and persistence in some solar cycles than in others. Evidence is adduced for a variation in the solar rotation period, as measured by sunspot number, of as much as two days between different solar cycles.

  5. Solar Eruptions Initiated in Sigmoidal Active Regions

    NASA Astrophysics Data System (ADS)

    Savcheva, Antonia

    2016-07-01

    active regions that have been shown to possess high probability for eruption. They present a direct evidence of the existence of flux ropes in the corona prior to the impulsive phase of eruptions. In order to gain insight into their eruptive behavior and how they get destabilized we need to know their 3D magnetic field structure. First, we review some recent observations and modeling of sigmoidal active regions as the primary hosts of solar eruptions, which can also be used as useful laboratories for studying these phenomena. Then, we concentrate on the analysis of observations and highly data-constrained non-linear force-free field (NLFFF) models over the lifetime of several sigmoidal active regions, where we have captured their magnetic field structure around the times of major flares. We present the topology analysis of a couple of sigmoidal regions pointing us to the probable sites of reconnection. A scenario for eruption is put forward by this analysis. We demonstrate the use of this topology analysis to reconcile the observed eruption features with the standard flare model. Finally, we show a glimpse of how such a NLFFF model of an erupting region can be used to initiate a CME in a global MHD code in an unprecedented realistic manner. Such simulations can show the effects of solar transients on the near-Earth environment and solar system space weather.

  6. High performance solar Stirling system

    NASA Technical Reports Server (NTRS)

    Stearns, J. W.; Haglund, R.

    1981-01-01

    A full-scale Dish-Stirling system experiment, at a power level of 25 kWe, has been tested during 1981 on the Test Bed Concentrator No. 2 at the Parabolic Dish Test Site, Edwards, CA. Test components, designed and developed primarily by industrial contractors for the Department of Energy, include an advanced Stirling engine driving an induction alternator, a directly-coupled solar receiver with a natural gas combustor for hybrid operation and a breadboard control system based on a programmable controller and standard utility substation components. The experiment demonstrated practicality of the solar Stirling application and high system performance into a utility grid. This paper describes the design and its functions, and the test results obtained.

  7. High efficiency solar panel /HESP/

    NASA Technical Reports Server (NTRS)

    Stella, P. M.; Gay, C.; Uno, F.; Scott-Monck, J.

    1978-01-01

    A family of high efficiency, weldable silicon solar cells, incorporating nearly every feature of advanced cell technology developed in the past four years, was produced and subjected to space qualification testing. This matrix contained both field and non-field cells ranging in thickness from 0.10 mm to 0.30 mm, and in base resistivity from nominal two to one hundred ohm-cm. Initial power outputs as high as 20 mW/sq cm (14.8% AM0 efficiency) were produced by certain cell types within the matrix.

  8. Coronal Activity and Extended Solar Cycles

    NASA Astrophysics Data System (ADS)

    Altrock, R. C.

    2012-12-01

    Wilson et al. (1988, Nature 333, 748) discussed a number of solar parameters, which appear at high latitudes and gradually migrate towards the equator, merging with the sunspot "butterfly diagram". They found that this concept had been identified by earlier investigators extending back to 1957. They named this process the "Extended Solar Cycle" (ESC). Altrock (1997, Solar Phys. 170, 411) found that this process continued in Fe XIV 530.3 nm emission features. In cycles 21 - 23 solar maximum occurred when the number of Fe XIV emission regions per day > 0.19 (averaged over 365 days and both hemispheres) first reached latitudes 18°, 21° and 21°, for an average of 20° ± 1.7°. Other recent studies have shown that Torsional Oscillation (TO) negative-shear zones are co-located with the ESC from at least 50° down to the equator and also in the zones where the Rush to the Poles occur. These phenomena indicate that coronal activity occurring up to 50° and higher latitudes is related to TO shear zones, another indicator that the ESC is an important solar process. Another high-latitude process, which appears to be connected with the ESC, is the "Rush to the Poles" ("Rush") of polar crown prominences and their associated coronal emission, including Fe XIV. The Rush is is a harbinger of solar maximum (cf. Altrock, 2003, Solar Phys. 216, 343). Solar maximum in cycles 21 - 23 occurred when the center line of the Rush reached a critical latitude. These latitudes were 76°, 74° and 78°, respectively, for an average of 76° ± 2°. Applying the above conclusions to Cycle 24 is difficult due to the unusual nature of this cycle. Cycle 24 displays an intermittent "Rush" that is only well-defined in the northern hemisphere. In 2009 an initial slope of 4.6°/yr was found in the north, compared to an average of 9.4 ± 1.7 °/yr in the previous three cycles. This early fit to the Rush would have reached 76° at 2014.6. However, in 2010 the slope increased to 7.5°/yr (an increase

  9. Influence of solar activity on fibrinolysis and fibrinogenolysis. [statistical correlation between solar flare and blood coagulation indices

    NASA Technical Reports Server (NTRS)

    Marchenko, V. I.

    1974-01-01

    During periods of high solar activity fibrinolysis and fibrinogenolysis are increased. A direct correlative relationship is established between the indices of fibrinolysis, fibrinogenolysis and solar flares which were recorded two days before the blood was collected for analysis.

  10. Effects of Solar Magnetic Activity on the Charge States of Minor Ions of Solar Wind

    NASA Astrophysics Data System (ADS)

    Wang, Xuyu

    We present an investigation of the effects of solar magnetic activity on the charge states of minor ions (Fe, Si, Mg, Ne, O, C) in the solar wind using ACE solar wind data, the Current Sheet Source Surface (CSSS) model of the corona and SoHO/MDI data during the 23rd solar cycle. We found that the mean charge states indicate a clear trend to increase with the solar activity when the solar wind speed is above 550 km/s. Below this speed, no significant solar activity dependence is found. When displayed as a function of solar wind speed, iron is different from other elements in that it displays lower charge states in slow wind than in fast wind. The percentages of the high charge states for species with higher m/q (Fe) increase with the solar wind speed, while for the species with lower m/q (Si,Mg, O, C), the percentages of the high charge states decrease with the solar wind speed.

  11. Solar irradiance measurements - Minimum through maximum solar activity

    NASA Technical Reports Server (NTRS)

    Lee, R. B., III; Gibson, M. A.; Shivakumar, N.; Wilson, R.; Kyle, H. L.; Mecherikunnel, A. T.

    1991-01-01

    The Earth Radiation Budget Satellite (ERBS) and the NOAA-9 spacecraft solar monitors were used to measure the total solar irradiance during the period October 1984 to December 1989. Decreasing trends in the irradiance measurements were observed as sunspot activity decreased to minimum levels in 1986; after 1986, increasing trends were observed as sunspot activity increased. The magnitude of the irradiance variability was found to be approximately 0.1 percent between sunspot minimum and maximum (late 1989). When compared with the 1984 to 1989 indices of solar magnetic activity, the irradiance trends appear to be in phase with the 11-year sunspot cycle. Both irradiance series yielded 1,365/sq Wm as the mean value of the solar irradiance, normalized to the mean earth/sun distance. The monitors are electrical substitution, active-cavity radiometers with estimated measurement precisions and accuracies of less than 0.02 and 0.2 percent, respectively.

  12. Ionospheric response to the High Speed Solar Streams during last solar minimum

    NASA Astrophysics Data System (ADS)

    Mosna, Zbysek; Koucka Knizova, Petra; Georgieva, Katya

    Ionosphere is a highly variable system. Response of ionospheric plasma to the High Speed Solar Streams (HSS) by means of critical frequencies fof2, heights of maximum electron concentration hmf2 and the occurrence of sporadic E-layer during last prolonged solar minimum is presented and we compare it to previous studies. State of the ionosphere depends on the daytime, season, phase of solar cycle etc. The extent of ionospheric response to the solar event (HSS, CME etc.) is a subject of mentioned conditions and strength of solar event itself but it also significantly depends on the actual geomagnetic and ionospheric situation and the memory of the system, e.g. length of the preceding quiet or disturbed period. Ionospheric storms have been relatively widely studied. However, last solar minimum gives us an exceptional possibility to study ionospheric processes under conditions of unusually long time of low solar activity.

  13. Solar activity and oscillation frequency splittings

    NASA Technical Reports Server (NTRS)

    Woodard, M. F.; Libbrecht, K. G.

    1993-01-01

    Solar p-mode frequency splittings, parameterized by the coefficients through order N = 12 of a Legendre polynomial expansion of the mode frequencies as a function of m/L, were obtained from an analysis of helioseismology data taken at Big Bear Solar Observatory during the 4 years 1986 and 1988-1990 (approximately solar minimum to maximum). Inversion of the even-index splitting coefficients confirms that there is a significant contribution to the frequency splittings originating near the solar poles. The strength of the polar contribution is anti correlated with the overall level or solar activity in the active latitudes, suggesting a relation to polar faculae. From an analysis of the odd-index splitting coefficients we infer an uppor limit to changes in the solar equatorial near-surface rotatinal velocity of less than 1.9 m/s (3 sigma limit) between solar minimum and maximum.

  14. Workshop on Solar Activity, Solar Wind, Terrestrial Effects, and Solar Acceleration

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A summary of the proceedings from the workshop are presented. The areas covered were solar activity, solar wind, terrestrial effects, and solar acceleration. Specific topics addressed include: (1) solar cycle manifestations, both large and small scale, as well as long-term and short-term changes, including transients such as flares; (2) sources of solar wind, as identified by interplanetary observations including coronal mass ejections (CME's) or x-ray bright points, and the theory for and evolution of large-scale and small-scale structures; (3) magnetosphere responses, as observed by spacecraft, to variable solar wind and transient energetic particle emissions; and (4) origin and propagation of solar cosmic rays as related to solar activity and terrestrial effects, and solar wind coronal-hole relationships and dynamics.

  15. Sustainable Buildings. Using Active Solar Power

    SciTech Connect

    Sharp, M. Keith; Barnett, Russell

    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.

  16. Dynamo theory prediction of solar activity

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth H.

    1988-01-01

    The dynamo theory technique to predict decadal time scale solar activity variations is introduced. The technique was developed following puzzling correlations involved with geomagnetic precursors of solar activity. Based upon this, a dynamo theory method was developed to predict solar activity. The method was used successfully in solar cycle 21 by Schatten, Scherrer, Svalgaard, and Wilcox, after testing with 8 prior solar cycles. Schatten and Sofia used the technique to predict an exceptionally large cycle, peaking early (in 1990) with a sunspot value near 170, likely the second largest on record. Sunspot numbers are increasing, suggesting that: (1) a large cycle is developing, and (2) that the cycle may even surpass the largest cycle (19). A Sporer Butterfly method shows that the cycle can now be expected to peak in the latter half of 1989, consistent with an amplitude comparable to the value predicted near the last solar minimum.

  17. The Relationship Between Solar Coronal X-Ray Brightness and Active Region Magnetic Fields: A Study Using High-Resolution Hinode Observations

    NASA Astrophysics Data System (ADS)

    Hazra, Soumitra; Nandy, Dibyendu; Ravindra, B.

    2015-03-01

    By using high-resolution observations of nearly co-temporal and co-spatial Solar Optical Telescope spectropolarimeter and X-Ray Telescope coronal X-ray data onboard Hinode, we revisit the problematic relationship between global magnetic quantities and coronal X-ray brightness. Co-aligned vector magnetogram and X-ray data were used for this study. The total X-ray brightness over active regions is well correlated with integrated magnetic quantities such as the total unsigned magnetic flux, the total unsigned vertical current, and the area-integrated square of the vertical and horizontal magnetic fields. On accounting for the inter-dependence of the magnetic quantities, we inferred that the total magnetic flux is the primary determinant of the observed integrated X-ray brightness. Our observations indicate that a stronger coronal X-ray flux is not related to a higher non-potentiality of active-region magnetic fields. The data even suggest a slightly negative correlation between X-ray brightness and a proxy of active-region non-potentiality. Although there are small numerical differences in the established correlations, the main conclusions are qualitatively consistent over two different X-ray filters, the Al-poly and Ti-poly filters, which confirms the strength of our conclusions and validate and extend earlier studies that used low-resolution data. We discuss the implications of our results and the constraints they set on theories of solar coronal heating.

  18. Solar Flares and the High Energy Solar Spectroscopic Imager (HESSI)

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    Solar flares are the biggest explosions in the solar system. They are important both for understanding explosive events in the Universe and for their impact on human technology and communications. The satellite-based HESSI is designed to study the explosive release of energy and the acceleration of electrons, protons, and other charged particles to high energies in solar flares. HESSI produces "color" movies of the Sun in high-energy X rays and gamma rays radiated by these energetic particles. HESSI's X-ray and gamma-ray images of flares are obtained using techniques similar to those used in radio interferometry. Ground-based radio observations of the Sun provide an important complement to the HESSI observations of solar flares. I will describe the HESSI Project and the high-energy aspects of solar flares, and how these relate to radio astronomy techniques and observations.

  19. Nanoflare activity in the solar chromosphere

    SciTech Connect

    Jess, D. B.; Mathioudakis, M.; Keys, P. H.

    2014-11-10

    We use ground-based images of high spatial and temporal resolution to search for evidence of nanoflare activity in the solar chromosphere. Through close examination of more than 1 × 10{sup 9} pixels in the immediate vicinity of an active region, we show that the distributions of observed intensity fluctuations have subtle asymmetries. A negative excess in the intensity fluctuations indicates that more pixels have fainter-than-average intensities compared with those that appear brighter than average. By employing Monte Carlo simulations, we reveal how the negative excess can be explained by a series of impulsive events, coupled with exponential decays, that are fractionally below the current resolving limits of low-noise equipment on high-resolution ground-based observatories. Importantly, our Monte Carlo simulations provide clear evidence that the intensity asymmetries cannot be explained by photon-counting statistics alone. A comparison to the coronal work of Terzo et al. suggests that nanoflare activity in the chromosphere is more readily occurring, with an impulsive event occurring every ∼360 s in a 10,000 km{sup 2} area of the chromosphere, some 50 times more events than a comparably sized region of the corona. As a result, nanoflare activity in the chromosphere is likely to play an important role in providing heat energy to this layer of the solar atmosphere.

  20. Tsunami related to solar and geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino

    2016-04-01

    The authors of this study wanted to verify the existence of a correlation between earthquakes of high intensity capable of generating tsunami and variations of solar and Earth's 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 four earthquakes of high intensity that have generated tsunamis: 1) Japan M9 earthquake occurred on March 11, 2011 at 05:46 UTC; 2) Japan M7.1 earthquake occurred on October 25, 2013 at 17:10 UTC; 3) Chile M8.2 earthquake occurred on April 1, 2014 at 23:46 UTC; 4) Chile M8.3 earthquake occurred on September 16, 2015 at 22:54 UTC. The data relating to the four 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 and by Space Weather Prediction Center of Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation (IZMIRAN), Troitsk, Moscow Region. The results of the study, in agreement with what already

  1. The Three-Dimenstional Solar Wind at Solar Activity Minimum

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.

    1998-01-01

    In late 1997, the Ulysses spacecraft completed its first orbit around the Sun, observing the properties of the heliosphere at all latitudes between 80 degrees South and 80 degrees North. Because the mission occurred during a period of near-minimum solar activity, the configuration of the solar wind and interplanetary magnetic field were particularly simple, thus allowing confident comparisons between the properties of the polar corona observed by instruments of the Spartan and SOHO spacecraft and the resulting properties of the solar wind.

  2. Solar neutrinos, solar flares, solar activity cycle and the proton decay

    NASA Technical Reports Server (NTRS)

    Raychaudhuri, P.

    1985-01-01

    It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino data, but it appears that the neutrino flux which may be generated during the large solar cosmic ray events cannot in any way effect the solar neutrino data in Davis experiment. Only initial stage of mixing between the solar core and solar outer layers after the sunspot maximum in the solar activity cycle can explain the higher (run number 27 and 71) of solar neutrino data in Davis experiment. But solar flare induced atmospheric neutrino flux may have effect in the nucleon decay detector on the underground. The neutrino flux from solar cosmic rays may be a useful guide to understand the background of nucleon decay, magnetic monopole search, and the detection of neutrino flux in sea water experiment.

  3. Validation of solar wind high-speed stream predictions

    NASA Astrophysics Data System (ADS)

    Reiss, Martin; Temmer, Manuela; Veronig, Astrid; Nikolic, Ljubomir; Schöngassner, Florian; Vennerstrøm, Susanne

    2016-04-01

    Solar wind high-speed streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. As major contributors to space weather disturbances at times of low solar activity, prediction models of solar wind high-speed streams are becoming highly desirable. We present a verification analysis of two operational solar wind prediction models (empirical model, Wang-Sheeley-Arge like model) by comparing the model runs for the period 2011 to 2014 with in-situ plasma measurements from the ACE spacecraft located at 1 AU. We find that both prediction models achieve a similar accuracy but demonstrate the tendency to under-predict and over-predict events of solar wind high-speed streams, respectively. General advantages and disadvantages of both models are diagnosed and outlined.

  4. Ionospheric effects of the extreme solar activity of February 1986

    NASA Technical Reports Server (NTRS)

    Boska, J.; Pancheva, D.

    1989-01-01

    During February 1986, near the minimum of the 11 year Solar sunspot cycle, after a long period of totally quiet solar activity (R sub z = 0 on most days in January) a period of a suddenly enhanced solar activity occurred in the minimum between solar cycles 21 and 22. Two proton flares were observed during this period. A few other flares, various phenomena accompanying proton flares, an extremely severe geomagnetic storm and strong disturbances in the Earth's ionosphere were observed in this period of enhanced solar activity. Two active regions appeared on the solar disc. The flares in both active regions were associated with enhancement of solar high energy proton flux which started on 4 February of 0900 UT. Associated with the flares, the magnetic storm with sudden commencement had its onset on 6 February 1312 UT and attained its maximum on 8 February (Kp = 9). The sudden enhancement in solar activity in February 1986 was accompanied by strong disturbances in the Earth's ionosphere, SIDs and ionospheric storm. These events and their effects on the ionosphere are discussed.

  5. On the Relationship Between Solar Wind Speed, Geomagnetic Activity, and the Solar Cycle Using Annual Values

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2008-01-01

    The aa index can be decomposed into two separate components: the leading sporadic component due to solar activity as measured by sunspot number and the residual or recurrent component due to interplanetary disturbances, such as coronal holes. For the interval 1964-2006, a highly statistically important correlation (r = 0.749) is found between annual averages of the aa index and the solar wind speed (especially between the residual component of aa and the solar wind speed, r = 0.865). Because cyclic averages of aa (and the residual component) have trended upward during cycles 11-23, cyclic averages of solar wind speed are inferred to have also trended upward.

  6. Solar Activity Predictions Based on Solar Dynamo Theories

    NASA Astrophysics Data System (ADS)

    Schatten, Kenneth H.

    2009-05-01

    We review solar activity prediction methods, statistical, precursor, and recently the Dikpati and the Choudhury groups’ use of numerical flux-dynamo methods. Outlining various methods, we compare precursor techniques with weather forecasting. Precursors involve events prior to a solar cycle. First started by the Russian geomagnetician Ohl, and then Brown and Williams; the Earth's field variations near solar minimum was used to predict the next solar cycle, with a correlation of 0.95. From the standpoint of causality, as well as energetically, these relationships were somewhat bizarre. One index used was the "number of anomalous quiet days,” an antiquated, subjective index. Scientific progress cannot be made without some suspension of disbelief; otherwise old paradigms become tautologies. So, with youthful naïveté, Svalgaard, Scherrer, Wilcox and I viewed the results through rose-colored glasses and pressed ahead searching for understanding. We eventually fumbled our way to explaining how the Sun could broadcast the state of its internal dynamo to Earth. We noted one key aspect of the Babcock-Leighton Flux Dynamo theory: the polar field at the end of a cycle serves as a seed for the next cycle's growth. Near solar minimum this field usually bathes the Earth, and thereby affects geomagnetic indices then. We found support by examining 8 previous solar cycles. Using our solar precursor technique we successfully predicted cycles 21, 22 and 23 using WSO and MWSO data. Pesnell and I improved the method using a SODA (SOlar Dynamo Amplitude) Index. In 2005, nearing cycle 23's minimum, Svalgaard and I noted an unusually weak polar field, and forecasted a small cycle 24. We discuss future advances: the flux-dynamo methods. As far as future solar activity, I shall let the Sun decide; it will do so anyhow.

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

    ERIC Educational Resources Information Center

    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…

  8. Sunshot Initiative High Penetration Solar Portal

    DOE Data Explorer

    The DOE SunShot Initiative is a collaborative national initiative to make solar energy cost-competitive with other forms of energy by the end of the decade. Reducing the installed cost of solar energy systems by about 75% will drive widespread large-scale adoption of this renewable energy and restore U.S. leadership in the global clean energy race. The High Penetration Solar Portal was created as a resource to aggregate the most relevant and timely information related to high penetration solar scenarios and integrating solar into the grid. The site is designed so that utilities, grant awardees, regulators, researchers, and other solar professionals can easily share data, case studies, lessons learned, and demonstration project findings. [from https://solarhighpen.energy.gov/about_the_high_penetration_solar_portal

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

    NASA Astrophysics Data System (ADS)

    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

  10. Annual DOE Active Solar Heating and Cooling Contractors Review meeting

    NASA Astrophysics Data System (ADS)

    1981-09-01

    Ninety three project summaries dicussing the following aspects of active solar heating and cooling are presented: 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.

  11. Science Activities in Energy: Solar Energy II.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Included in this science activities energy package are 14 activities related to solar energy for secondary students. Each activity is outlined on a single card and is introduced by a question such as: (1) how much solar heat comes from the sun? or (2) how many times do you have to run water through a flat-plate collector to get a 10 degree rise in…

  12. Gap between active and passive solar heating

    SciTech Connect

    Balcomb, J.D.

    1985-01-01

    The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problems, performance prediction, performance modeling, monitoring, and cooling concerns. Trends are analyzed, both for solar space heating and for service water heating. A tendency for the active and passive technologies to be converging is observed. Several recommendations for narrowing the gap are presented.

  13. High efficiency, long life terrestrial solar panel

    NASA Technical Reports Server (NTRS)

    Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

    1977-01-01

    The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

  14. Solar collector manufacturing activity, 1992

    SciTech Connect

    Not Available

    1993-11-09

    This report presents data provided by US-based manufacturers and importers of solar collectors. Summary data on solar thermal collector shipments are presented for the years 1974 through 1992. Summary data on photovoltaic cell and module shipments are presented for the years 1982 through 1992. Detailed information for solar thermal collectors and photovoltaic cells and modules are presented for 1992. Appendix A describes the survey methodology. Appendix B contains the 1992 survey forms and instructions. Appendices C and D list the companies that responded to the 1992 surveys and granted permission for their names and addresses to appear in the report. Appendix E provides selected tables from this report with data shown in the International System of Units (SI) metric units. Appendix F provides an estimate of installed capacity and energy production from solar collectors for 1992.

  15. MASC: Magnetic Activity of the Solar Corona

    NASA Astrophysics Data System (ADS)

    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

  16. Science Activities in Energy: Solar Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 12 activities relating to solar energy. Activities are simple, concrete experiments for fourth, fifth, and sixth grades, which illustrate principles and problems relating to energy. Each activity is outlined on a single card which is introduced by a question. A teacher's supplement…

  17. Solar activities and Climate change hazards

    NASA Astrophysics Data System (ADS)

    Hady, A. A., II

    2014-12-01

    Throughout the geological history of Earth, climate change is one of the recurrent natural hazards. In recent history, the impact of man brought about additional climatic change. Solar activities have had notable effect on palaeoclimatic changes. Contemporary, both solar activities and building-up of green-house gases effect added to the climatic changes. This paper discusses if the global worming caused by the green-house gases effect will be equal or less than the global cooling resulting from the solar activities. In this respect, we refer to the Modern Dalton Minimum (MDM) which stated that starting from year 2005 for the next 40 years; the earth's surface temperature will become cooler than nowadays. However the degree of cooling, previously mentioned in old Dalton Minimum (c. 210 y ago), will be minimized by building-up of green-house gases effect during MDM period. Regarding to the periodicities of solar activities, it is clear that now we have a new solar cycle of around 210 years. Keywords: Solar activities; solar cycles; palaeoclimatic changes; Global cooling; Modern Dalton Minimum.

  18. Modified conducting polymer films having high catalytic activity for use as counter electrodes in rigid and flexible dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Ke, Chun-Ren; Chang, Chih-Ching; Ting, Jyh-Ming

    2015-06-01

    We report replacing platinum based counter electrode (CE) in dye-sensitized solar cell (DSSC) with conducting polymer based CE. Conducting polymers are prepared through mixing poly-(3,4-ethylenedioxythio phene):poly-(styrene sulfonic acid) (PEDOT:PSS) with Triton. The polymer mixture is spin-coated on indium tin oxide (ITO)-coated glass substrate and ITO-coated polyethylene naphthalate plastic substrate to form a CE for use in both rigid and flexible DSSCs, respectively. The PEDOT:PSS-Triton polymer not only is transparent (up to 93%) and highly conductive but also exhibits better catalytic activity than the expensive platinum. The DSSC fabricated using the PEDOT:PSS-Triton conducting polymer CE shows better performance or higher power conversion efficiency than that using Pt-based CE, either rigid or flexible.

  19. Boeing's High Voltage Solar Tile Test Results

    NASA Technical Reports Server (NTRS)

    Reed, Brian J.; Harden, David E.; Ferguson, Dale C.; Snyder, David B.

    2002-01-01

    Real concerns of spacecraft charging and experience with solar array augmented electrostatic discharge arcs on spacecraft have minimized the use of high voltages on large solar arrays despite numerous vehicle system mass and efficiency advantages. Boeing's solar tile (patent pending) allows high voltage to be generated at the array without the mass and efficiency losses of electronic conversion. Direct drive electric propulsion and higher power payloads (lower spacecraft weight) will benefit from this design. As future power demand grows, spacecraft designers must use higher voltage to minimize transmission loss and power cable mass for very large area arrays. This paper will describe the design and discuss the successful test of Boeing's 500-Volt Solar Tile in NASA Glenn's Tenney chamber in the Space Plasma Interaction Facility. The work was sponsored by NASA's Space Solar Power Exploratory Research and Technology (SERT) Program and will result in updated high voltage solar array design guidelines being published.

  20. Castro Valley High School's Solar Panels

    NASA Astrophysics Data System (ADS)

    Lew, A.; Ham, S.; Shin, Y.; Yang, W.; Lam, J.

    2014-12-01

    Solar panels are photovoltaic cells that are designed to convert the sun's kinetic energy to generate usable energy in the form of electricity. Castro Valley High School has tried to offset the cost of electricity by installing solar panels, costing the district approximately 3.29 million dollars, but have been installed incorrectly and are not operating at peak efficency. By using trigonometry we deduced that Castro Valley High School's south facing solar panels were at an incline of 10o and that the east and west facing solar panels are at an incline of 5o. By taking the averages of the optimum angles for the months of September through May, roughly when school is in session, we found that the optimum angle for south facing solar panels should be roughly 46o. This shows that Castro Valley High School has not used it's budget to its full potential due to the fact that the solar panels were haphazardly installed.

  1. Hinode Captures Images of Solar Active Region

    NASA Video Gallery

    In these images, Hinode's Solar Optical Telescope (SOT) zoomed in on AR 11263 on August 4, 2011, five days before the active region produced the largest flare of this cycle, an X6.9. We show images...

  2. A History of Solar Activity over Millennia

    NASA Astrophysics Data System (ADS)

    Usoskin, Ilya G.

    2013-03-01

    Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview of the special indices used to quantify different aspects of variable solar activity, with special emphasis upon sunspot number. Over long timescales, quantitative information about past solar activity can only be obtained using a method based upon indirect proxies, such as the cosmogenic isotopes 14C and 10Be in natural stratified archives (e.g., tree rings or ice cores). We give an historical overview of the development of the proxy-based method for past solar-activity reconstruction over millennia, as well as a description of the modern state. Special attention is paid to the verification and cross-calibration of reconstructions. It is argued that this method of cosmogenic isotopes makes a solid basis for studies of solar variability in the past on a long timescale (centuries to millennia) during the Holocene. A separate section is devoted to reconstructions of strong solar energetic-particle (SEP) events in the past, that suggest that the present-day average SEP flux is broadly consistent with estimates on longer timescales, and that the occurrence of extra-strong events is unlikely. Finally, the main features of the long-term evolution of solar magnetic activity, including the statistics of grand minima and maxima occurrence, are summarized and their possible implications, especially for solar/stellar dynamo theory, are discussed.

  3. Volcanic eruptions and solar activity

    NASA Technical Reports Server (NTRS)

    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.

  4. 11 -year planetary index of solar activity

    NASA Astrophysics Data System (ADS)

    Okhlopkov, Victor

    In papers [1,2] introduced me parameter - the average difference between the heliocentric longitudes of planets ( ADL ) , which was used for comparison with solar activity. The best connection of solar activity ( Wolf numbers used ) was obtained for the three planets - Venus, Earth and Jupiter. In [1,2] has been allocated envelope curve of the minimum values ADL which has a main periodicity for 22 years and describes well the alternating series of solar activity , which also has a major periodicity of 22. It was shown that the minimum values of the envelope curve extremes ADL planets Venus, Earth and Jupiter are well matched with the 11- year solar activity cycle In these extremes observed linear configuration of the planets Venus, Earth and Jupiter both in their location on one side of the Sun ( conjunctions ) and at the location on the opposite side of the Sun ( three configurations ) This work is a continuation of the above-mentioned , and here for minimum ADL ( planets are in conjunction ) , as well as on the minimum deviation of the planets from a line drawn through them and Sun at the location of the planets on opposite sides of the Sun , compiled index (denoted for brevity as JEV ) that uniquely describes the 11- year solar cycle A comparison of the index JEV with solar activity during the time interval from 1000 to 2013 conducted. For the period from 1000 to 1699 used the Schove series of solar activity and the number of Wolf (1700 - 2013 ) During the time interval from 1000 to 2013 and the main periodicity of the solar activity and the index ADL is 11.07 years. 1. Okhlopkov V.P. Cycles of Solar Activity and the Configurations of Planets // Moscow University Physics Bulletin, 2012 , Vol. 67 , No. 4 , pp. 377-383 http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.3103/S0027134912040108. 2 Okhlopkov VP, Relationship of Solar Activity Cycles to Planetary Configurations // Bulletin of the Russian Academy of Sciences. Physics, 2013 , Vol. 77 , No. 5

  5. Is Solar Activity Once More Fainting?

    NASA Astrophysics Data System (ADS)

    Mares Aguilar, C. E.; Schröder, K.-P.; Song, G.

    2013-04-01

    After an anomalously long and deep minimum, will the Sun now once again reach a period of weaker activity cycles, which would affect northern hemisphere winter climate? We here discuss the current state and outlook of solar activity, and we propose to monitor the solar Ca II K line emission “as a star”, as part of the regular observing schedule of the Hamburg robotic telescope, which is bound to move to Guanajuato this year (2012). In fact, the chromospheric Ca II K line emission is a good proxy for the solar far-ultraviolet flux, as both are generated at about the same plasma temperatures (12-15,000 K) and both originate from the same active regions (plages). The solar ultraviolet flux, in turn, warms the stratosphere by photo dissociation of ozone and other molecules and, consequently, affects the strength of the North Atlantic Oscillation (NOA).

  6. Solar Activity Studies using Microwave Imaging Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.

    2016-01-01

    We report on the status of solar cycle 24 based on polar prominence eruptions (PEs) and microwave brightness enhancement (MBE) information obtained by the Nobeyama radioheliograph. The north polar region of the Sun had near-zero field strength for more than three years (2012-2015) and ended only in September 2015 as indicated by the presence of polar PEs and the lack of MBE. The zero-polar-field condition in the south started only around 2013, but it ended by June 2014. Thus the asymmetry in the times of polarity reversal switched between cycle 23 and 24. The polar MBE is a good proxy for the polar magnetic field strength as indicated by the high degree of correlation between the two. The cross-correlation between the high- and low-latitude MBEs is significant for a lag of approximately 5.5 to 7.3 years, suggesting that the polar field of one cycle indicates the sunspot number of the next cycle in agreement with the Babcock-Leighton mechanism of solar cycles. The extended period of near-zero field in the north-polar region should result in a weak and delayed sunspot activity in the northern hemisphere in cycle 25.

  7. High efficiency solar photovoltaic power module concept

    NASA Technical Reports Server (NTRS)

    Bekey, I.

    1978-01-01

    The investigation of a preliminary concept for high efficiency solar power generation in space is presented. The concept was a synergistic combination of spectral splitting, tailored bandgap cells, high concentration ratios, and cool cell areas.

  8. High-temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Merritt, Danielle; Raffaelle, Ryne P.; Scheiman, David

    2005-01-01

    The vast majority of space probes to date have relied upon photovoltaic power generation. If future missions designed to probe environments close to the sun (Figure 1) will be able to use such power generation, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. The significant problem is that solar cells lose performance at high temperatures.

  9. Photochemical Models for Mars' Upper Atmosphere and Ionosphere at Low, Medium, and High Solar Activity: Implications for H2, D, and Evolution of Water

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, V. A.

    2002-05-01

    Self-consistent models for 11 neutral and 18 ion species from 80 to 300 km on Mars have been developed by solving the continuity equations including ambipolar diffusion for ions. The models were calculated for the conditions of the HST, FUSE, and Mariner 6, 7 observations of D, H2, and H, respectively, when solar activity index was 25, 61, and 88 on Mars orbit, respectively. Special care was taken to simulate the processes of H2 and HD dissociation in the reactions with CO2+, O+, CO+, N2+, N+, Ar+, O(1D), and by photoelectrons. Thermal and nonthermal escape velocities were used as the upper boundary conditions for H2, H, HD, D, and He. The calculated ion density profiles at various solar activity and the column reaction rates provide complete quantitative information for behavior of each ion, its formation and loss. The HCO+ ion is abundant in Mars' ionosphere because it is a final product of many reactions of other ions with H2 and does not react with neutral species. The H2 and D mixing ratios of 15 ppm and 11 ppb chosen to fit the FUSE and HST observations of H2 and D, respectively, result in (HD/H2)/(HDO/H2O) = 0.41. This value agrees with the depletion of D in H2 because of the smaller HDO photolysis cross section, the preferential condensation of HDO above the hygropause, and the fractionation in chemical reactions that result in the formation of H2. Therefore the controversial problem of deuterium fractionation is solved throughout the atmosphere. Isotope fractionation factor for hydrogen escape is equal to 0.055, 0.082, and 0.167 for low, medium, and high solar activity, respectively, and the solar cycle mean value is 0.105. The polar caps shrink or dissappear at high obliquity, and water in the polar caps is in isotopic equilibrium with the atmospheric water. Using the water amount of 14 m in the polar caps, the fractionation factor, the present D/H ratio and that at the end of hydrodynamic escape (5.5 and 1.9 times the terrestrial ratio, respectively

  10. Very High Efficiency Solar Cell Modules

    SciTech Connect

    Barnett, A.; Kirkpatrick, D.; Honsberg, C.; Moore, D.; Wanlass, M.; Emery, K.; Schwartz, R.; Carlson, D.; Bowden, S.; Aiken, D.; Gray, A.; Kurtz, S.; Kazmerski, L., et al

    2009-01-01

    The Very High Efficiency Solar Cell (VHESC) program is developing integrated optical system - PV modules for portable applications that operate at greater than 50% efficiency. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space. Our approach is driven by proven quantitative models for the solar cell design, the optical design, and the integration of these designs. Optical systems efficiency with an optical efficiency of 93% and solar cell device results under ideal dichroic splitting optics summing to 42.7 {+-} 2.5% are described.

  11. Global water cycle and solar activity variations

    NASA Astrophysics Data System (ADS)

    Al-Tameemi, Muthanna A.; Chukin, Vladimir V.

    2016-05-01

    The water cycle is the most active and most important component in the circulation of global mass and energy in the Earth system. Furthermore, water cycle parameters such as evaporation, precipitation, and precipitable water vapour play a major role in global climate change. In this work, we attempt to determine the impact of solar activity on the global water cycle by analyzing the global monthly values of precipitable water vapour, precipitation, and the Solar Modulation Potential in 1983-2008. The first object of this study was to calculate global evaporation for the period 1983-2008. For this purpose, we determined the water cycle rate from satellite data, and precipitation/evaporation relationship from 10 years of Planet Simulator model data. The second object of our study was to investigate the relationship between the Solar Modulation Potential (solar activity index) and the evaporation for the period 1983-2008. The results showed that there is a relationship between the solar modulation potential and the evaporation values for the period of study. Therefore, we can assume that the solar activity has an impact on the global water cycle.

  12. Polarization aberrations in the solar activity measurements experiments (SAMEX) solar vector magnetograph

    NASA Technical Reports Server (NTRS)

    Mcguire, James P., Jr.; Chipman, Russell A.

    1989-01-01

    An optical design and polarization analysis of the Air Force/NASA Solar Activity Measurements Experiments solar vector magnetograph optical system is performed. Polarization aberration theory demonstrates that conventional telescope coating designs introduce unacceptably high levels of polarization aberrations into the optical system. Several ultralow polarization mirror and lens coatings designs for this instrument are discussed. Balancing of polarization aberrations at different surfaces is demonstrated.

  13. The solar activity measurements experiments (SAMEX) for improved scientific understanding of solar activity

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The Solar Activity Measurements Experiments (SAMEX) mission is described. It is designed to provide a look at the interactions of magnetic fields and plasmas that create flares and other explosive events on the sun in an effort to understand solar activity and the nature of the solar magnetic field. The need for this mission, the instruments to be used, and the expected benefits of SAMEX are discussed.

  14. Temporal offsets among solar activity indicators

    NASA Astrophysics Data System (ADS)

    Ramesh, K. B.; Vasantharaju, N.

    2014-04-01

    Temporal offsets between the time series of solar activity indicators provide important clues regarding the physical processes responsible for the cyclic variability in the solar atmosphere. Hysteresis patterns generated between any two indicators were popularly used to study their morphological features and further to understand their inter relationships. We use time series of different solar indicators to understand the possible cause-and-effect criteria between their respective source regions. Sensitivity of the upper atmosphere to the activity underneath might play an important role in introducing different evolutionary patterns in the profiles of solar indicators and in turn cause temporal offsets between them. Limitations in the observations may also cause relative shifts in the time series.

  15. Prominences: The Key to Understanding Solar Activity

    NASA Technical Reports Server (NTRS)

    Karpen, Judy T.

    2011-01-01

    Prominences are spectacular manifestations of both quiescent and eruptive solar activity. The largest examples can be seen with the naked eye during eclipses, making prominences among the first solar features to be described and catalogued. Steady improvements in temporal and spatial resolution from both ground- and space-based instruments have led us to recognize how complex and dynamic these majestic structures really are. Their distinguishing characteristics - cool knots and threads suspended in the hot corona, alignment along inversion lines in the photospheric magnetic field within highly sheared filament channels, and a tendency to disappear through eruption - offer vital clues as to their origin and dynamic evolution. Interpreting these clues has proven to be contentious, however, leading to fundamentally different models that address the basic questions: What is the magnetic structure supporting prominences, and how does so much cool, dense plasma appear in the corona? Despite centuries of increasingly detailed observations, the magnetic and plasma structures in prominences are poorly known. Routine measurements of the vector magnetic field in and around prominences have become possible only recently, while long-term monitoring of the underlying filament-channel formation process also remains scarce. The process responsible for prominence mass is equally difficult to establish, although we have long known that the chromosphere is the only plausible source. As I will discuss, however, the motions and locations of prominence material can be used to trace the coronal field, thus defining the magnetic origins of solar eruptions. A combination of observations, theory, and numerical modeling must be used to determine whether any of the competing theories accurately represents the physics of prominences. I will discuss the criteria for a successful prominence model, compare the leading models, and present in detail one promising, comprehensive scenario for

  16. Active solar heating and cooling information user study

    SciTech Connect

    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.

  17. High-Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The vast majority of satellites and near-earth probes developed to date have relied upon photovoltaic power generation. If future missions to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. For example, the equilibrium temperature of a Mercury surface station will be about 450 C, and the temperature of solar arrays on the proposed "Solar Probe" mission will extend to temperatures as high as 2000 C (although it is likely that the craft will operate on stored power rather than solar energy during the closest approach to the sun). Advanced thermal design principles, such as replacing some of the solar array area with reflectors, off-pointing, and designing the cells to reflect rather than absorb light out of the band of peak response, can reduce these operating temperature somewhat. Nevertheless, it is desirable to develop approaches to high-temperature solar cell design that can operate under temperature extremes far greater than today's cells. Solar cells made from wide bandgap (WBG) compound semiconductors are an obvious choice for such an application. In order to aid in the experimental development of such solar cells, we have initiated a program studying the theoretical and experimental photovoltaic performance of wide bandgap materials. In particular, we have been investigating the use of GaP, SiC, and GaN materials for space solar cells. We will present theoretical results on the limitations on current cell technologies and the photovoltaic performance of these wide-bandgap solar cells in a variety of space conditions. We will also give an overview of some of NASA's cell developmental efforts in this area and discuss possible future mission applications.

  18. Solar activity and Perseid meteor heights

    NASA Astrophysics Data System (ADS)

    Buček, M.; Porubčan, V.; Zigo, P.

    2012-04-01

    Photographic meteor heights of the Perseid meteoroid stream compiled in the IAU Meteor Data Center catalogue observed in 1939-1992, covering five solar activity cycles, are analyzed and their potential variation within a solar activity cycle is investigated and discussed. Of the 673 Perseids selected from the catalogue, the variations of the heights for three independent sets: 524 Perseids with known information on both heights, 397 with known brightness and 279 with the geocentric velocity within a one sigma limit, were investigated. The observed beginning and endpoint heights of the Perseids, normalized for the geocentric velocity and the absolute photographic magnitude correlated with the solar activity represented by the relative sunspot number R, do not exhibit a variation consistent with the solar activity cycle. The result, confirmed also by the correlation analysis, is derived for the mass ranges of larger meteoroids observed by photographic techniques. However, a possible variation of meteor heights controlled by solar activity for smaller meteoroids detected by television and radio techniques remains still open and has to be verified.

  19. Causality principles in solar activity -climate relations.

    NASA Astrophysics Data System (ADS)

    Stauning, Peter

    The relations between solar activity and the terrestrial climate have quite often been inves-tigated. In most cases the analyses have been based on comparisons between time series of solar activity parameters, for instance sunspot numbers, and terrestrial climate parameters, for instance global temperatures. However, many of the reported close relations are based on skilfully manipulated data and neglect of basic causality principles. For cause-effect relations to be reliably established, the variations in the causative function must obviously happen prior to the related effects. Thus it is problematic to use, for instance, running averages of parameters, if the result depends too much on posterior elements of the causative time series or precursory elements of the effects. Even more neglected are the causality principles for cause-effect rela-tions with a strongly varying source function, like for instance the 11 year solar activity cycle. In such cases damping of source variations by smoothing data series, introduces additional im-plied delays, which should be considered in the judgement of apparent correlations between the processed time series of cause and effect parameters. The presentation shall illustrate causal-ity relations between solar activity and terrestrial climate parameters and discuss examples of frequently quoted solar activity-climate relations, which violate basic causality principles.

  20. High efficiency, radiation-hard solar cells

    SciTech Connect

    Ager III, J.W.; Walukiewicz, W.

    2004-10-22

    The direct gap of the In{sub 1-x}Ga{sub x}N alloy system extends continuously from InN (0.7 eV, in the near IR) to GaN (3.4 eV, in the mid-ultraviolet). This opens the intriguing possibility of using this single ternary alloy system in single or multi-junction (MJ) solar cells of the type used for space-based surveillance satellites. To evaluate the suitability of In{sub 1-x}Ga{sub x}N as a material for space applications, high quality thin films were grown with molecular beam epitaxy and extensive damage testing with electron, proton, and alpha particle radiation was performed. Using the room temperature photoluminescence intensity as a indirect measure of minority carrier lifetime, it is shown that In{sub 1-x}Ga{sub x}N retains its optoelectronic properties at radiation damage doses at least 2 orders of magnitude higher than the damage thresholds of the materials (GaAs and GaInP) currently used in high efficiency MJ cells. This indicates that the In{sub 1-x}Ga{sub x}N is well-suited for the future development of ultra radiation-hard optoelectronics. Critical issues affecting development of solar cells using this material system were addressed. The presence of an electron-rich surface layer in InN and In{sub 1-x}Ga{sub x}N (0 < x < 0.63) was investigated; it was shown that this is a less significant effect at large x. Evidence of p-type activity below the surface in Mg-doped InN was obtained; this is a significant step toward achieving photovoltaic action and, ultimately, a solar cell using this material.

  1. Theoretical predictions for ion composition in the high-latitude winter F-region for solar minimum and low magnetic activity

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Raitt, W. J.; Schunk, R. W.

    1981-01-01

    A simple plasma convection model is combined with an ionospheric-atmospheric density model in order to study the ion composition in the high-latitude winter F-region at solar minimum for low geomagnetic activity. The numerical study produces time-dependent, three-dimensional ion density distributions for the ions NO(+), O2(+), N2(+), O(+), N(+), and He(+). The high-latitude ionosphere above 54 deg N magnetic latitude is covered at altitudes between 160 and 800 km for one complete day. Among the conclusions are the following: the ion composition varies significantly with latitude, local time, altitude, and universal time; the variations in the ion composition with latitude and local time are in good agreement with the Atmosphere Explorer measurements both quantitatively and qualitatively; and at times and at certain locations the molecular ion density can be comparable to the O(+) density at 300 km, and at 200 km the O(+) density can be comparable to the molecular ion density.

  2. High temperature solar selective coatings

    DOEpatents

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  3. Achieving High Performance Perovskite Solar Cells

    NASA Astrophysics Data System (ADS)

    Yang, Yang

    2015-03-01

    Recently, metal halide perovskite based solar cell with the characteristics of rather low raw materials cost, great potential for simple process and scalable production, and extreme high power conversion efficiency (PCE), have been highlighted as one of the most competitive technologies for next generation thin film photovoltaic (PV). In UCLA, we have realized an efficient pathway to achieve high performance pervoskite solar cells, where the findings are beneficial to this unique materials/devices system. Our recent progress lies in perovskite film formation, defect passivation, transport materials design, interface engineering with respect to high performance solar cell, as well as the exploration of its applications beyond photovoltaics. These achievements include: 1) development of vapor assisted solution process (VASP) and moisture assisted solution process, which produces perovskite film with improved conformity, high crystallinity, reduced recombination rate, and the resulting high performance; 2) examination of the defects property of perovskite materials, and demonstration of a self-induced passivation approach to reduce carrier recombination; 3) interface engineering based on design of the carrier transport materials and the electrodes, in combination with high quality perovskite film, which delivers 15 ~ 20% PCEs; 4) a novel integration of bulk heterojunction to perovskite solar cell to achieve better light harvest; 5) fabrication of inverted solar cell device with high efficiency and flexibility and 6) exploration the application of perovskite materials to photodetector. Further development in film, device architecture, and interfaces will lead to continuous improved perovskite solar cells and other organic-inorganic hybrid optoelectronics.

  4. North-south asymmetry of different solar activity features during solar cycle 23

    NASA Astrophysics Data System (ADS)

    Bankoti, Neeraj Singh; Joshi, Navin Chandra; Pande, Seema; Pande, Bimal; Pandey, Kavita

    2010-08-01

    A study on north-south (N-S) asymmetry of different solar activity features (DSAF) such as solar proton events, solar active prominences [total, low (⩽40°) and high (⩾50°) latitudes], H α flare indices, soft X-ray flares, monthly mean sunspot areas and monthly mean sunspot numbers carried out from May 1996 to October 2008. Study shows a southern dominance of DSAF during this period. During the rising phase of the cycle 23 the number of DSAF approximately equals on both, the northern and the southern hemispheres. But these activities tend to shift from northern to southern hemisphere during the period 1998-1999. The statistical significance of the asymmetry time series using a χ2-test of goodness of fit indicates that in most of the cases the asymmetry is highly significant, meaning thereby that the asymmetry is a real feature in the N-S distribution of DSAF.

  5. High-flux solar photon processes

    SciTech Connect

    Lorents, D C; Narang, S; Huestis, D C; Mooney, J L; Mill, T; Song, H K; Ventura, S

    1992-06-01

    This study was commissioned by the National Renewable Energy Laboratory (NREL) for the purpose of identifying high-flux photoprocesses that would lead to beneficial national and commercial applications. The specific focus on high-flux photoprocesses is based on the recent development by NREL of solar concentrator technology capable of delivering record flux levels. We examined photolytic and photocatalytic chemical processes as well as photothermal processes in the search for processes where concentrated solar flux would offer a unique advantage. 37 refs.

  6. High-Strength Glass for Solar Applications

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.

    1987-01-01

    Technology for strengthening thin sections reviewed. Report reviews technology of high-strength glass for such solar applications as heat collectors, reflectors, and photovoltaic arrays. Discusses most feasible methods - heat strengthening and chemical strengthening of increasing strength of glass for solar-energy use. Also estimates cost and availability of high-strength glass and considers physical characteristics, amenability to back-silvering, and effects of atmospheric contamination.

  7. Methodologies for high efficiency perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Park, Nam-Gyu

    2016-06-01

    Since the report on long-term durable solid-state perovskite solar cell in 2012, perovskite solar cells based on lead halide perovskites having organic cations such as methylammonium CH3NH3PbI3 or formamidinium HC(NH2)2PbI3 have received great attention because of superb photovoltaic performance with power conversion efficiency exceeding 22 %. In this review, emergence of perovskite solar cell is briefly introduced. Since understanding fundamentals of light absorbers is directly related to their photovoltaic performance, opto-electronic properties of organo lead halide perovskites are investigated in order to provide insight into design of higher efficiency perovskite solar cells. Since the conversion efficiency of perovskite solar cell is found to depend significantly on perovskite film quality, methodologies for fabricating high quality perovskite films are particularly emphasized, including various solution-processes and vacuum deposition method.

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

    SciTech Connect

    Not Available

    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)

  9. Models of Impulsively Heated Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Klimchuk, J.

    2009-05-01

    A number of attempts to model solar active regions with steady coronal heating have been modestly successful at reproducing the observed soft X-ray emission, but they fail dramatically at explaining EUV observations. Since impulsive heating (nanoflare) models can reproduce individual EUV loops, it seems reasonable to consider that entire active regions are impulsively heated. However, nanoflares are characterized by many parameters, such as magnitude, duration, and time delay between successive events, and these parameters may depend on the strength of the magnetic field or the length of field lines, for example, so a wide range of active region models must be examined. We have recently begun such a study. Each model begins with a magnetic "skeleton” obtained by extrapolating an observed photospheric magnetogram into the corona. Field lines are populated with plasma using our highly efficient hydro code called Enthalpy Based Thermal Evolution of Loops (EBTEL). We then produce synthetic images corresponding to emission line or broad-band observations. By determining which set of nanoflare parameters best reproduces actual observations, we hope to constrain the properties of the heating and ultimately to reveal the physical mechanism. We here report on the initial progress of our study.

  10. The Magnetic Classification of Solar Active Regions 1992-2015

    NASA Astrophysics Data System (ADS)

    Jaeggli, S. A.; Norton, A. A.

    2016-03-01

    The purpose of this Letter is to address a blindspot in our knowledge of solar active region (AR) statistics. To the best of our knowledge, there are no published results showing the variation of the Mount Wilson magnetic classifications as a function of solar cycle based on modern observations. We show statistics for all ARs reported in the daily Solar Region Summary from 1992 January 1 to 2015 December 31. We find that the α and β class ARs (including all sub-groups, e.g., βγ, βδ) make up fractions of approximately 20% and 80% of the sample, respectively. This fraction is relatively constant during high levels of activity however, an increase in the α fraction to about 35% and and a decrease in the β fraction to about 65% can be seen near each solar minimum and are statistically significant at the 2σ level. Over 30% of all ARs observed during the years of solar maxima were appended with the classifications γ and/or δ, while these classifications account for only a fraction of a percent during the years near the solar minima. This variation in the AR types indicates that the formation of complex ARs may be due to the pileup of frequent emergence of magnetic flux during solar maximum, rather than the emergence of complex, monolithic flux structures.

  11. Solar activity and the mean global temperature

    NASA Astrophysics Data System (ADS)

    Erlykin, A. D.; Sloan, T.; Wolfendale, A. W.

    2009-01-01

    The variation with time from 1956 to 2002 of the globally averaged rate of ionization produced by cosmic rays in the atmosphere is deduced and shown to have a cyclic component of period roughly twice the 11 year solar cycle period. Long term variations in the global average surface temperature as a function of time since 1956 are found to have a similar cyclic component. The cyclic variations are also observed in the solar irradiance and in the mean daily sun spot number. The cyclic variation in the cosmic ray rate is observed to be delayed by 2-4 years relative to the temperature, the solar irradiance and daily sun spot variations suggesting that the origin of the correlation is more likely to be direct solar activity than cosmic rays. Assuming that the correlation is caused by such solar activity, we deduce that the maximum recent increase in the mean surface temperature of the Earth which can be ascribed to this activity is {\\lesssim }14% of the observed global warming.

  12. Solar system events at high spatial resolution

    SciTech Connect

    Baines, K H; Gavel, D T; Getz, A M; Gibbartd, S G; MacIntosh, B; Max, C E; McKay, C P; Young, E F; de Pater, I

    1999-02-19

    Until relatively recent advances in technology, astronomical observations from the ground were limited in image resolution by the blurring effects of earth's atmosphere. The blur extent, ranging typically from 0.5 to 2 seconds of arc at the best astronomical sights, precluded ground-based observations of the details of the solar system's moons, asteroids, and outermost planets. With the maturing of a high resolution image processing technique called speckle imaging the resolution limitation of the atmosphere can now be largely overcome. Over the past three years they have used speckle imaging to observe Titan, a moon of Saturn with an atmospheric density comparable to Earth's, Io, the volcanically active innermost moon of Jupiter, and Neptune, a gas giant outer planet which has continually changing planet-encircling storms. These observations were made at the world's largest telescope, the Keck telescope in Hawaii and represent the highest resolution infrared images of these objects ever taken.

  13. Solar Activity, Different Geomagnetic Activity Levels and Acute Myocardial Infarction

    NASA Astrophysics Data System (ADS)

    Dimitrova, Svetla; Jordanova, Malina; Stoilova, Irina; Taseva, Tatiana; Maslarov, Dimitar

    Results on revealing a possible relationship between solar activity (SA) and geomagnetic activity (GMA) and acute myocardial infarction (AMI) morbidity are presented. Studies were based on medical data covering the period from 1.12.1995 to 31.12.2004 and concerned daily distribution of patients with AMI diagnose (in total 1192 cases) from Sofia region on the day of admission at the hospital. Analysis of variance (ANOVA) was applied to check the significance of GMA intensity effect and the type of geomagnetic storms, those caused by Magnetic Clouds (MC) and by High Speed Solar Wind Streams (HSSWS), on AMI morbidity. Relevant correlation coefficients were calculated. Results revealed statistically significant positive correlation between considered GMA indices and AMI. ANOVA revealed that AMI number was signifi- cantly increased from the day before (-1st) till the day after (+1st) geomagnetic storms with different intensities. Geomagnetic storms caused by MC were related to significant increase of AMI number in comparison with the storms caused by HSSWS. There was a trend for such different effects even on -1st and +1st day.

  14. Hot spots and active longitudes: Organization of solar activity as a probe of the interior

    NASA Technical Reports Server (NTRS)

    Bai, Taeil; Hoeksema, J. Todd; Scherrer, Phil H.

    1995-01-01

    In order to investigate how solar activity is organized in longitude, major solar flares, large sunspot groups, and large scale photospheric magnetic field strengths were analyzed. The results of these analyses are reported. The following results are discussed: hot spots, initially recognized as areas of high concentration of major flares, are the preferred locations for the emergence of big sunspot groups; double hot spots appear in pairs that rotate at the same rate separated by about 180 deg in longitude, whereas, single hot spots have no such companions; the northern and southern hemispheres behave differently in organizing solar activity in longitude; the lifetime of hot spots range from one to several solar cycles; a hot spot is not always active throughout its lifetime, but goes through dormant periods; and hot spots with different rotational periods coexist in the same hemisphere during the same solar cycle.

  15. Forecast for solar cycle 23 activity: a progress report

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    2001-08-01

    At the 25th International Cosmic Ray Conference (ICRC) at Durban, South Africa, I announced the discovery of a three cycle quasi-periodicity in the ion chamber data string assembled by me, for the 1937 to 1994 period (Conf. Pap., v. 2, p. 109, 1997). It corresponded in time with a similar quasi-periodicity observed in the dataset for the planetary index Ap. At the 26th ICRC at Salt Lake City, UT, I reported on our analysis of the Ap data to forecast the amplitude of solar cycle 23 activity (Conf. Pap., v. 2, pl. 260, 1999). I predicted that cycle 23 will be moderate (a la cycle 17), notwithstanding the early exuberant forecasts of some solar astronomers that cycle 23, "may be one of the greatest cycles in recent times, if not the greatest." Sunspot number data up to April 2001 indicate that our forecast appears to be right on the mark. We review the solar, interplanetary and geophysical data and describe the important lessons learned from this experience. 1. Introduction Ohl (1971) was the first to realize that Sun may be sending us a subliminal message as to its intent for its activity (Sunspot Numbers, SSN) in the next cycle. He posited that the message was embedded in the geomagnetic activity (given by sum Kp). Schatten at al (1978) suggested that Ohl hypothesis could be understood on the basis of the model proposed by Babcock (1961) who suggested that the high latitude solar poloidal fields, near a minimum, emerge as the toroidal fields on opposite sides of the solar equator. This is known as the Solar Dynamo Model. One can speculate that the precursor poloidal solar field is entrained in the high speed solar wind streams (HSSWS) from the coronal holes which are observed at Earth's orbit during the descending phase of the previous cycle. The interaction

  16. The HESP (High Energy Solar Physics) project

    NASA Technical Reports Server (NTRS)

    Kai, K.

    1986-01-01

    A project for space observations of solar flares for the coming solar maximum phase is briefly described. The main objective is to make a comprehensive study of high energy phenomena of flares through simultaneous imagings in both hard and soft X-rays. The project will be performed with collaboration from US scientists. The HESP (High Energy Solar Physics) WG of ISAS (Institute of Space and Astronautical Sciences) has extensively discussed future aspects of space observations of high energy phenomena of solar flares based on successful results of the Hinotori mission, and proposed a comprehensive research program for the next solar maximum, called the HESP (SOLAR-A) project. The objective of the HESP project is to make a comprehensive study of both high energy phenomena of flares and quiet structures including pre-flare states, which have been left uncovered by SMM and Hinotori. For such a study simultaneous imagings with better resolutions in space and time in a wide range of energy will be extremely important.

  17. Seismic Holography of Solar Activity

    NASA Technical Reports Server (NTRS)

    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.

  18. SPARTAN high resolution solar studies

    NASA Technical Reports Server (NTRS)

    Bruner, Marilyn E.

    1993-01-01

    This report summarizes the work performed on Contract NAS5-29739, a sub-orbital research program directed toward the study of the geometry of and physical conditions in matter found in the upper layers of the solar atmosphere. The report describes a new sounding rocket payload developed under the contract, presents a guide to the contents of semiannual reports submitted during the contract, discusses the results of the first flight of the payload and the progress on scientific analysis. A bibliography of papers and publications is included.

  19. Solar Energy Project, Activities: Chemistry & Physics.

    ERIC Educational Resources Information Center

    Tullock, Bruce, Ed.; And Others

    This guide contains lesson plans and outlines of science activities which present concepts of solar energy in the context of chemistry and physics experiments. Each unit presents an introduction to the unit; objectives; required skills and knowledge; materials; method; questions; recommendations for further work; and a teacher information sheet.…

  20. Solar Energy Project, Activities: Earth Science.

    ERIC Educational Resources Information Center

    Tullock, Bruce, Ed.; And Others

    This guide contains lesson plans and outlines of science activities which present concepts of solar energy in the context of earth science experiments. Each unit presents an introduction; objectives; skills and knowledge needed; materials; method; questions; recommendations for further study; and a teacher information sheet. The teacher…

  1. Recent Perplexing Behavior in Solar Activity Indices

    NASA Astrophysics Data System (ADS)

    Lopresto, James C.

    1997-05-01

    Calcium K and Hα and SOHO He II UV plage and sunspot ara have been monitored using images on the INTERNET since November of 1992. The purpose of the project is to determine the degree of correlation between changing plage area and solar irradiance changes (also obtained via the INTERNET). Also the project provides a low cost process to involve undergraduates in astronomy research. When using weighted weekly averages for both spot Hα plage pixel counts, we see the expected decline from the last maximum. The activity continues to decline, or at best, has flattened out over the past several months. In contrast, the K-line plage pixel count from both Big Bear and Sacramento Peak show an upswing since mid-1995 or earlier. The k2 measurments from both Kitt Peak and Sacramento Peak are in general agreement with the spot and Hα behavior, indicating wer are in, or barely passed minimum. Images high in the chromosphere, detailing the magnetic network, may be more senstive to smaller field changes. This might be a partial explanation for the earlier upswing in K line and He 304 activity, which are receiving radiation near or at the top of the chromosphere.

  2. Solar Selective Coatings for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Shumway, Dean A.

    2003-01-01

    Solar selective coatings are envisioned for use on minisatellites, for applications where solar energy is to be used to power heat engines or to provide thermal energy for remote regions in the interior of the spacecraft. These coatings are designed to have the combined properties of high solar absorptance and low infrared emittance. The coatings must be durable at elevated temperatures. For thermal bus applications, the temperature during operation is likely to be near 100 C. For heat engine applications. the temperature is expected to be much greater. The objective of this work was to screen candidate solar selective coatings for their high temperature durability. Candidate solar selective coatings were composed of molecular mixtures of metal and dielectric, including: nickel and aluminum oxide, titanium and aluminum oxide, and platinum and aluminum oxide. To identify high temperature durability, the solar absorptance and infrared emittance of the candidate coatings were evaluated initially, and after heating to temperatures in the range of 400 C to 700 C. The titanium and aluminum oxide molecular mixture was found to be the most durable.

  3. Initiation of non-tropical thunderstorms by solar activity

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Goldberg, R. A.

    1976-01-01

    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 combined influence of high-energy solar protons and decreased cosmic ray intensities, both of which are associated with active solar events. The protons produce excess ionization near and above 20km, while the Forbush decreases a lowered conductivity and enhanced fair-weather atmospheric electric field below that altitude. Consequent effects ultimately lead to a charge distribution similar to that found in thunderclouds, and then other cloud physics processes take over to generate the intense electric fields required for lightning discharge.

  4. Division II: Commission 10: Solar Activity

    NASA Astrophysics Data System (ADS)

    van Driel-Gesztelyi, Lidia; Scrijver, Karel J.; Klimchuk, James A.; Charbonneau, Paul; Fletcher, Lyndsay; Hasan, S. Sirajul; Hudson, Hugh S.; Kusano, Kanya; Mandrini, Cristina H.; Peter, Hardi; Vršnak, Bojan; Yan, Yihua

    2015-08-01

    The Business Meeting of Commission 10 was held as part of the Business Meeting of Division II (Sun and Heliosphere), chaired by Valentin Martínez-Pillet, the President of the Division. The President of Commission 10 (C10; Solar activity), Lidia van Driel-Gesztelyi, took the chair for the business meeting of C10. She summarised the activities of C10 over the triennium and the election of the incoming OC.

  5. Forecasts of solar and geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Joselyn, Joann

    1987-01-01

    Forecasts of solar and geomagnetic activity are critical since these quantities are such important inputs to the thermospheric density models. At this time in the history of solar science there is no way to make such a forecast from first principles. Physical theory applied to the Sun is developing rapidly, but is still primitive. Techniques used for forecasting depend upon the observations over about 130 years, which is only twelve solar cycles. It has been noted that even-numbered cycles systematically tend to be smaller than the odd-numbered ones by about 20 percent. Another observation is that for the last 12 cycle pairs, an even-numbered sunspot cycle looks rather like the next odd-numbered cycle, but with the top cut off. These observations are examples of approximate periodicities that forecasters try to use to achieve some insight into the nature of an upcoming cycle. Another new and useful forecasting aid is a correlation that has been noted between geomagnetic indices and the size of the next solar cycle. Some best estimates are given concerning both activities.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

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

    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. MAGNETIC ENERGY SPECTRA IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Abramenko, Valentyna; Yurchyshyn, Vasyl

    2010-09-01

    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, {alpha}, of the energy spectrum, E(k) {approx} k{sup -}{alpha}, and the total spectral energy, W = {integral}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 {alpha} and W as A = 10{sup b}({alpha}W){sup 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.

  9. Division E Commission 10: Solar Activity

    NASA Astrophysics Data System (ADS)

    Schrijver, Carolus J.; Fletcher, Lyndsay; van Driel-Gesztelyi, Lidia; Asai, Ayumi; Cally, Paul S.; Charbonneau, Paul; Gibson, Sarah E.; Gomez, Daniel; Hasan, Siraj S.; Veronig, Astrid M.; Yan, Yihua

    2016-04-01

    After more than half a century of community support related to the science of ``solar activity'', IAU's Commission 10 was formally discontinued in 2015, to be succeeded by C.E2 with the same area of responsibility. On this occasion, we look back at the growth of the scientific disciplines involved around the world over almost a full century. Solar activity and fields of research looking into the related physics of the heliosphere continue to be vibrant and growing, with currently over 2,000 refereed publications appearing per year from over 4,000 unique authors, publishing in dozens of distinct journals and meeting in dozens of workshops and conferences each year. The size of the rapidly growing community and of the observational and computational data volumes, along with the multitude of connections into other branches of astrophysics, pose significant challenges; aspects of these challenges are beginning to be addressed through, among others, the development of new systems of literature reviews, machine-searchable archives for data and publications, and virtual observatories. As customary in these reports, we highlight some of the research topics that have seen particular interest over the most recent triennium, specifically active-region magnetic fields, coronal thermal structure, coronal seismology, flares and eruptions, and the variability of solar activity on long time scales. We close with a collection of developments, discoveries, and surprises that illustrate the range and dynamics of the discipline.

  10. DASL-Data and Activities for Solar Learning

    NASA Technical Reports Server (NTRS)

    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.

  11. Solar Wind and Magnetic Storms in 24-th Cycle of Solar Activity

    NASA Astrophysics Data System (ADS)

    Val'chuk, T. E.

    2013-01-01

    Slow growth of 24-th solar cycle allows adding of this cycle to the type of low cycles. Geomagnetic activity is not expensive too - strong geomagnetic storms were absent in the beginning of growth branch of this cycle. Very prolonged minimum was lasting about 4 years. We may remember that century minimum of solar activity was proposed after XX century high strong cycles. It may be - we look this situation now in 2012. Our work is connected with sporadic phenomena in 24-th cycle. These more or less intensive variations of solar activity are not predicted, they are caused by flowing up of new magnetic fields of spots, the excitement of flares, intensive plasma flows, coronal mass ejections (CME) and filament eruptions. Now two last versions (CME and filaments) are primary. Geomagnetic activity on a descending phase of solar cycle depends on quality of coronal holes providing the recurrent geomagnetic storms. Sporadic phenomena, which generated geomagnetic storms in Earth magnetosphere if flare flows reached the Earth magnetosphere and transferred it the energy are more interesting for us - they are the valuable characteristics of 24-th cycle. The disturbed period of several geomagnetic storms was generated by solar active region N11429. It is one sample only, this case is difficult and indicative. Replacing each other scenarios describe geomagnetic variations at the beginning of March 2012. Detailed consideration of this interval revealed its communication with sporadic events on the Sun. The structural configuration of plasma in flare flows was defined by means fractal dimension calculations of solar plasma parameters: velocity Vx and density N in flare streams.

  12. Cosmic rays, solar activity and the climate

    NASA Astrophysics Data System (ADS)

    Sloan, T.; Wolfendale, A. W.

    2013-12-01

    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.

  13. Solar activities at Sandia National Laboratories

    SciTech Connect

    Klimas, P.C.; Hasti, D.E.

    1994-03-01

    The use of renewable energy technologies is typically thought of as an integral part of creating and sustaining an environment that maximizes the overall quality of life of the Earth`s present inhabitants and does not leave an undue burden on future generations. Sandia National Laboratories has been a leader in developing and deploying many of these technologies over the last two decades. A common but special aspect of all of these activities is that they are all conducted in cooperation with various types of partners. Some of these partners have an interest in seeing these systems grow in the marketplace, while others are primarily concerned with economic benefits that can come from immediate use of these renewable energy systems. This paper describes solar thermal and photovoltaic technology activities at Sandia that are intended to accelerate the commercialization of these solar systems.

  14. Cosmic Rays, Solar Activity and the Climate

    NASA Astrophysics Data System (ADS)

    Sloan, T.

    2013-02-01

    Although it is generally believed that the increase in the mean global surface temperature since industrialisation 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 paper a simplified version of the standard picture of the role of greenhouse gases in causing the global warming since industrialisation 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.

  15. Solar activities at Sandia National Laboratories

    NASA Astrophysics Data System (ADS)

    Klimas, Paul C.; Hasti, David E.

    The use of renewable energy technologies is typically thought of as an integral part of creating and sustaining an environment that maximizes the overall quality of life of the Earth's present inhabitants and does not leave an undue burden on future generations. Sandia National Laboratories has been a leader in developing and deploying many of these technologies over the last two decades. A common but special aspect of all of these activities is that they are all conducted in cooperation with various types of partners. Some of these partners have an interest in seeing these systems grow in the marketplace, while others are primarily concerned with economic benefits that can come from immediate use of these renewable energy systems. This paper describes solar thermal and photovoltaic technology activities at Sandia that are intended to accelerate the commercialization of these solar systems.

  16. Geomagnetic responses to the solar wind and the solar activity

    NASA Technical Reports Server (NTRS)

    Svalgaard, L.

    1975-01-01

    Following some historical notes, the formation of the magnetosphere and the magnetospheric tail is discussed. The importance of electric fields is stressed and the magnetospheric convection of plasma and magnetic field lines under the influence of large-scale magnetospheric electric fields is outlined. Ionospheric electric fields and currents are intimately related to electric fields and currents in the magnetosphere and the strong coupling between the two regions is discussed. The energy input of the solar wind to the magnetosphere and upper atmosphere is discussed in terms of the reconnection model where interplanetary magnetic field lines merge or connect with the terrestrial field on the sunward side of the magnetosphere. The merged field lines are then stretched behind earth to form the magnetotail so that kinetic energy from the solar wind is converted into magnetic energy in the field lines in the tail. Localized collapses of the crosstail current, which is driven by the large-scale dawn/dusk electric field in the magnetosphere, divert part of this current along geomagnetic field lines to the ionosphere, causing substorms with auroral activity and magnetic disturbances. The collapses also inject plasma into the radiation belts and build up a ring current. Frequent collapses in rapid succession constitute the geomagnetic storm.

  17. The Magnetic Origins of Solar Activity

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.

    2012-01-01

    The defining physical property of the Sun's corona is that the magnetic field dominates the plasma. This property is the genesis for all solar activity ranging from quasi-steady coronal loops to the giant magnetic explosions observed as coronal mass ejections/eruptive flares. The coronal magnetic field is also the fundamental driver of all space weather; consequently, understanding the structure and dynamics of the field, especially its free energy, has long been a central objective in Heliophysics. The main obstacle to achieving this understanding has been the lack of accurate direct measurements of the coronal field. Most attempts to determine the magnetic free energy have relied on extrapolation of photospheric measurements, a notoriously unreliable procedure. In this presentation I will discuss what measurements of the coronal field would be most effective for understanding solar activity. Not surprisingly, the key process for driving solar activity is magnetic reconnection. I will discuss, therefore, how next-generation measurements of the coronal field will allow us to understand not only the origins of space weather, but also one of the most important fundamental processes in cosmic and laboratory plasmas.

  18. Solar irradiance variations due to active regions

    SciTech Connect

    Oster, L.; Schatten, K.H.; Sofia, S.

    1982-05-15

    We have been able to reproduce the variations of the solar irradiance observed by ACRIM to an accuracy of better than +- 0.4 W m/sup -2/, assuming that during the 6 month observation period in 1980 the solar luminosity was constant. The improvement over previous attempts is primarily due to the inclusion of faculae. The reproduction scheme uses simple geometrical data on spot and facula areas, and conventional parameters for the respective fluxes and angular dependencies. The quality of reproduction is not very sensitive to most of the details of these parameters; nevertheless, there conventional parameters cannot be very different from their actual values in the solar atmosphere. It is interesting that the time average of the integrated excess emission (over directions) of the faculae cancels out the integrated deficit produced by the spots, within an accuracy of about 10%. If this behavior were maintained over longer periods of time, say, on the order of an activity cycle, active regions could be viewed as a kind of lighthouse where the energy deficit near the normal direction, associated with the spots, is primarily reemitted close to the tangential directions by the faculae. The currently available data suggest that energy ''storage'' associated with the redirection of flux near active regions on the Sun is comparable to the lifetime of the faculae.

  19. High efficiency solar cell processing

    NASA Technical Reports Server (NTRS)

    Ho, F.; Iles, P. A.

    1985-01-01

    At the time of writing, cells made by several groups are approaching 19% efficiency. General aspects of the processing required for such cells are discussed. Most processing used for high efficiency cells is derived from space-cell or concentrator cell technology, and recent advances have been obtained from improved techniques rather than from better understanding of the limiting mechanisms. Theory and modeling are fairly well developed, and adequate to guide further asymptotic increases in performance of near conventional cells. There are several competitive cell designs with promise of higher performance ( 20%) but for these designs further improvements are required. The available cell processing technology to fabricate high efficiency cells is examined.

  20. Dependence of the amplitude of Pc5-band magnetic field variations on the solar wind and solar activity

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazue; Yumoto, Kiyohumi; Claudepierre, Seth G.; Sanchez, Ennio R.; Troshichev, Oleg A.; Janzhura, Alexander S.

    2012-04-01

    We have studied the dependence of the amplitude of magnetic field variations in the Pc5 band (1.6-6.7 mHz) on the solar wind and solar activity. Solar wind parameters considered are the bulk velocity Vsw and the variation of the solar wind dynamic pressure δPsw. The solar activity dependence is examined by contrasting observations made in 2001 (solar activity maximum) and 2006 (solar activity declining phase). We calculated hourly Pc5 amplitude using data from geostationary satellites at L = 6.8 and ground stations covering 1 < L < 9. The amplitude is positively correlated with both Vsw and δPsw, but the degree of correlation varies with L and magnetic local time. As measured by the correlation coefficient, the amplitude dependence on both Vsw and δPsw is stronger on the dayside than on the nightside, and the dependence on Vsw (δPsw) tends to be stronger at higher (lower) L, with the relative importance of the two solar wind parameters switching at L ˜ 5. We attribute the Vsw control to the Kelvin-Helmholtz instability on the magnetopause, occurring both at high and low latitudes, and the δPsw control to buffeting of the magnetosphere by variation of solar wind dynamic pressure. The GOES amplitude is higher at the solar maximum at all local times and the same feature is seen on the ground in the dawn sector at L > 6. A radial shift of the fast mode wave turning point, associated with the solar cycle variation of magnetosphere mass density, is a possible cause of this solar activity dependence.

  1. Solar Spectral Irradiance, Solar Activity, and the Near-Ultra-Violet

    NASA Astrophysics Data System (ADS)

    Fontenla, J. M.; Stancil, P. C.; Landi, E.

    2015-08-01

    The previous calculations of the Solar Spectral Irradiance (SSI) by the Solar Radiation Physical Modeling, version 2 system, are updated in this work by including new molecular photodissociation cross-sections of important species, and many more levels and lines in its treatment of non-LTE radiative transfer. The current calculations including the new molecular photodissociation opacities produce a reduced over-ionizaton of heavy elements in the lower chromosphere and solve the problems with prior studies of the UV SSI in the wavelength range 160-400 nm and now reproduce the available observations with much greater accuracy. Calculations and observations of the near-UV at 0.1 nm resolution and higher are compared. The current set of physical models includes four quiet-Sun and five active-region components, from which radiance is computed for ten observing angles. These radiances are combined with images of the solar disk to obtain the SSI and Total Solar Irradiance and their variations. The computed SSI is compared with measurements from space at several nm resolution and agreement is found within the accuracy level of these measurements. An important result is that the near-UV SSI increase with solar activity is significant for the photodissociation of ozone in the terrestrial atmosphere because a number of highly variable upper chromospheric lines overlap the ozone Hartley band.

  2. High Efficiency Solar Integrated Roof Membrane Product

    SciTech Connect

    Partyka, Eric; Shenoy, Anil

    2013-05-15

    This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

  3. Solar activity, the QBO, and tropospheric responses

    NASA Technical Reports Server (NTRS)

    Tinsley, Brian A.; Brown, Geoffrey M.; Scherrer, Philip H.

    1989-01-01

    The suggestion that galactic cosmic rays (GCR) as modulated by the solar wind are the carriers of the component of solar variability that affects weather and climate has been discussed in the literature for 30 years, and there is now a considerable body of evidence that supports it. Variations of GCR occur with the 11 year solar cycle, matching the time scale of recent results for atmospheric variations, as modulated by the quasibiennial oscillation of equatorial stratospheric winds (the QBO). Variations in GCR occur on the time scale of centuries with a well defined peak in the coldest decade of the little ice age. New evidence is presented on the meteorological responses to GCR variations on the time scale of a few days. These responses include changes in the vertical temperature profile in the troposphere and lower stratosphere in the two days following solar flare related high speed plasma streams and associated GCR decreases, and in decreases in Vorticity Area Index (VAI) following Forbush decreases of GCR. The occurrence of correlations of GCR and meteorological responses on all three time scales strengthens the hypothesis of GCR as carriers of solar variability to the lower atmosphere. Both short and long term tropospheric responses are understandable as changes in the intensity of cyclonic storms initiated by mechanisms involving cloud microphysical and cloud electrification processes, due to changes in local ion production from changes in GCR fluxes and other high energy particles in the MeV to low GeV range. The nature of these mechanisms remains undetermined. Possible stratospheric wind (particularly QBO) effects on the transport of HNO3 and other constituents incorporated in cluster ions and possible condensation and freezing nuclei are considered as relevant to the long term variations.

  4. High efficiency low cost solar cell power

    NASA Technical Reports Server (NTRS)

    Bekey, I.; Blocker, W.

    1978-01-01

    A concept for generating high-efficiency, low-cost, solar-cell power is outlined with reference to solar cell parameters, optical concentrators, and thermal control procedures. A design for a 12.5-kw power module for space operation is discussed noting the optical system, spectrum splitter, light conversion system, cell cooling, power conditioner, and tracking mechanism. It is found that for an unconcentrated array, efficiency approaches 60% when ten or more bandgaps are used. For a 12-band system, a computer program distributed bandgaps for maximum efficiency and equal cell currents. Rigid materials and thin films have been proposed for optical components and prisms, gratings, and dichroic mirrors have been recommended for spectrum splitting. Various radiator concepts are noted including that of Weatherston and Smith (1960) and Hedgepeth and Knapp (1978). The concept may be suitable for the Solar Power Satellite.

  5. High-altitude solar power platform

    SciTech Connect

    Bailey, M.D.; Bower, M.V.

    1992-04-01

    Solar power is a preeminent alternative to conventional aircraft propulsion. With the continued advances in solar cells, fuel cells, and composite materials technology, the solar powered airplane is no longer a simple curiosity constrained to flights of several feet in altitude or minutes of duration. A high altitude solar powered platform (HASPP) has several potential missions, including communications and agriculture. In remote areas, a HASPP could be used as a communication link. In large farming areas, a HASPP could perform remote sensing of crops. The impact of HASPP in continuous flight for one year on agricultural monitoring mission is presented. This mission provides farmers with near real-time data twice daily from an altitude which allows excellant resolution on water conditions, crop diseases, and insect infestation. Accurate, timely data will enable farmers to increase their yield and efficiency. A design for HASPP for the foregoing mission is presented. In the design power derived from solar cells covering the wings is used for propulsion, avionics, and sensors. Excess power produced midday will be stored in fuel cells for use at night to maintain altitude and course.

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

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Miroshnichenko, Leonty I.; Fang, Cheng

    2015-07-01

    We present a study of seven large solar proton events in the current solar cycle 24 (from 2009 January up to the current date). They were recorded by the GOES spacecraft with the highest proton fluxes being over 200 pfu for energies >10 MeV. In situ particle measurements show that: (1) The profiles of the proton fluxes are highly dependent on the locations of their solar sources, namely flares or coronal mass ejections (CMEs), which confirms the “heliolongitude rules” associated with solar energetic particle fluxes; (2) The solar particle release (SPR) times fall in the decay phase of the flare emission, and are in accordance with the times when the CMEs travel to an average height of 7.9 solar radii; and (3) The time differences between the SPR and the flare peak are also dependent on the locations of the solar active regions. The results tend to support the scenario of proton acceleration by the CME-driven shock, even though there exists a possibility of particle acceleration at the flare site, with subsequent perpendicular diffusion of accelerated particles in the interplanetary magnetic field. We derive the integral time-of-maximum spectra of solar protons in two forms: a single power-law distribution and a power law roll-over with an exponential tail. It is found that the unique ground level enhancement that occurred in the event on 2012 May 17 displays the hardest spectrum and the largest roll-over energy which may explain why this event could extend to relativistic energies. Supported by the National Natural Science Foundation of China.

  7. Solar Energy Education. Renewable energy activities for earth science

    SciTech Connect

    Not Available

    1980-01-01

    A teaching manual is provided to aid teachers in introducing renewable energy topics to earth science students. The main emphasis is placed on solar energy. Activities for the student include a study of the greenhouse effect, solar gain for home heating, measuring solar radiation, and the construction of a model solar still to obtain fresh water. Instructions for the construction of apparatus to demonstrate a solar still, the greenhouse effect and measurement of the altitude and azimuth of the sun are included. (BCS)

  8. New approaches for high-efficiency solar cells. Final report

    SciTech Connect

    Bedair, S M; El-Masry, N A

    1997-12-01

    This report summarizes the activities carried out in this subcontract. These activities cover, first the atomic layer epitaxy (ALE) growth of GaAs, AlGaAs and InGaP at fairly low growth temperatures. This was followed by using ALE to achieve high levels of doping both n-type and p-type required for tunnel junctions (Tj) in the cascade solar cell structures. Then the authors studied the properties of AlGaAs/InGaP and AlGaAs/GaAs tunnel junctions and their performances at different growth conditions. This is followed by the use of these tunnel junctions in stacked solar cell structures. The effect of these tunnel junctions on the performance of stacked solar cells was studied at different temperatures and different solar fluences. Finally, the authors studied the effect of different types of black surface fields (BSF), both p/n and n/p GaInP solar cell structures, and their potential for window layer applications. Parts of these activities were carried in close cooperation with Dr. Mike Timmons of the Research Triangle Institute.

  9. Influence of solar activity on Jupiter's atmosphere

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.

    2016-05-01

    The influx of solar energy to different latitudes while Jupiter's orbital motion around the Sun varies significantly. This leads to a change in the optical and physical characteristics of its atmosphere. Analysis of the data for 1850-1991 on determination of the integral magnitude Mj Jupiter in the V filter, and a comparison with the changes of the Wolf numbers W, characterizing the variations of solar activity (SA) - showed that the change of Mj in maxima of the SA - has minima for odd, and maximums - for the even of SA cycles. That is, changing of the Jupiter brightness in visible light is much evident 22.3-year magnetic cycle, and not just about the 11.1-year cycle of solar activity. Analysis of the obtained in 1960-2015 data on the relative distribution of brightness along the central meridian of Jupiter, for which we calculated the ratio of the brightness Aj of northern to the southern part of the tropical and temperate latitudinal zones, allowed to approximate the change of Aj by sinusoid with a period of 11.91±0.07 earth years. Comparison of time variation of Aj from changes in the index of SA R, and the movement of the planet in its orbit - indicates the delay of response of the visible cloud layer in the atmosphere of the Sun's exposure mode for 6 years. This value coincides with the radiative relaxation of the hydrogen-helium atmosphere

  10. High spectral resolution in the solar spectrum

    NASA Technical Reports Server (NTRS)

    Baret, F.; Green, R. O.

    1994-01-01

    A session dedicated to high spectral resolution in the solar spectrum, covering topics of calibration, atmospheric correction, geology/pedology, inland water, and vegetation, is reported. The session showed a high degree of diversity in the topics and the approaches used. It was highlighted that high spectral resolution data could provide atmospherically corrected ground level calibrated reflectance values. Important advances were shown in the use of radiative transfer models applied either on water bodies or vegetation. Several studies highlighted the high degree of redundancy contained in high spectral resolution data.

  11. High efficiency solar cells combining a perovskite and a silicon heterojunction solar cells via an optical splitting system

    NASA Astrophysics Data System (ADS)

    Uzu, Hisashi; Ichikawa, Mitsuru; Hino, Masashi; Nakano, Kunihiro; Meguro, Tomomi; Hernández, José Luis; Kim, Hui-Seon; Park, Nam-Gyu; Yamamoto, Kenji

    2015-01-01

    We have applied an optical splitting system in order to achieve very high conversion efficiency for a full spectrum multi-junction solar cell. This system consists of multiple solar cells with different band gap optically coupled via an "optical splitter." An optical splitter is a multi-layered beam splitter with very high reflection in the shorter-wave-length range and very high transmission in the longer-wave-length range. By splitting the incident solar spectrum and distributing it to each solar cell, the solar energy can be managed more efficiently. We have fabricated optical splitters and used them with a wide-gap amorphous silicon (a-Si) solar cell or a CH3NH3PbI3 perovskite solar cell as top cells, combined with mono-crystalline silicon heterojunction (HJ) solar cells as bottom cells. We have achieved with a 550 nm cutoff splitter an active area conversion efficiency of over 25% using a-Si and HJ solar cells and 28% using perovskite and HJ solar cells.

  12. High efficiency solar cells combining a perovskite and a silicon heterojunction solar cells via an optical splitting system

    SciTech Connect

    Uzu, Hisashi E-mail: npark@skku.edu; Ichikawa, Mitsuru; Hino, Masashi; Nakano, Kunihiro; Meguro, Tomomi; Yamamoto, Kenji; Hernández, José Luis; Kim, Hui-Seon; Park, Nam-Gyu E-mail: npark@skku.edu

    2015-01-05

    We have applied an optical splitting system in order to achieve very high conversion efficiency for a full spectrum multi-junction solar cell. This system consists of multiple solar cells with different band gap optically coupled via an “optical splitter.” An optical splitter is a multi-layered beam splitter with very high reflection in the shorter-wave-length range and very high transmission in the longer-wave-length range. By splitting the incident solar spectrum and distributing it to each solar cell, the solar energy can be managed more efficiently. We have fabricated optical splitters and used them with a wide-gap amorphous silicon (a-Si) solar cell or a CH{sub 3}NH{sub 3}PbI{sub 3} perovskite solar cell as top cells, combined with mono-crystalline silicon heterojunction (HJ) solar cells as bottom cells. We have achieved with a 550 nm cutoff splitter an active area conversion efficiency of over 25% using a-Si and HJ solar cells and 28% using perovskite and HJ solar cells.

  13. Preferred longitudes in solar and stellar activity

    NASA Astrophysics Data System (ADS)

    Berdyugina, S. V.

    An analysis of the distribution of starspots on the surfaces of very active stars, such as RS CVn- FK Com-type stars as well as young solar analogs, reveals preferred longitudes of spot formation and their quasi-periodic oscillations, i.e. flip-flop cycles. A non-linear migration of the preferred longitudes suggests the presence of the differential rotation and variations of mean spot latitudes. It enables recovering stellar butterfly diagrams. Such phenomena are found to persist in the sunspot activity as well. A comparison of the observed properties of preferred longitudes on the Sun with those detected on more active stars leads to the conclusion that we can learn fine details of the stellar dynamo by studying the Sun, while its global parameters on the evolutionary time scale are provided by a sample of active stars.

  14. Evidence of plasma heating in solar microflares during the minimum of solar activity

    NASA Astrophysics Data System (ADS)

    Kirichenko, Alexey; Bogachev, Sergey

    We present a statistical study of 80 solar microflares observed during the deep minimum of solar activity between 23 and 24 solar cycles. Our analysis covers the following characteristics of the flares: thermal energy of flaring plasma, its temperature and its emission measure in soft X-rays. The data were obtained during the period from April to July of 2009, which was favorable for observations of weak events because of very low level of solar activity. The most important part of our analysis was an investigation of extremely weak microflares corresponding to X-ray class below A1.0. We found direct evidence of plasma heating in more than 90% of such events. Temperature of flaring plasma was determined under the isothermal approximation using the data of two solar instruments: imaging spectroheliometer MISH onboard Coronas-Photon spacecraft and X-ray spectrophotometer SphinX operating in energy range 0.8 - 15 keV. The main advantage of MISH is the ability to image high temperature plasma (T above 4 MK) without a low-temperature background. The SphinX data was selected due to its high sensitivity, which makes available the registration of X-ray emission from extremely weak microflares corresponding GOES A0.1 - A0.01 classes. The temperature we obtained lies in the range from 2.6 to 13.6 MK, emission measure, integrated over the range 1 - 8 Å - 2.7times10(43) - 4.9times10(47) cm (-3) , thermal energy of flaring region - 5times10(26) - 1.6times10(29) erg. We compared our results with the data obtained by Feldman et. al. 1996 and Ryan et. al. 2012 for solar flares with X-ray classes above A2.0 and conclude that the relation between X-ray class of solar flare and its temperature is strongly different for ordinary flares (above A2.0) and for weak microflares (A0.01 - A2.0). Our result supports the idea that weak solar events (microflares and nanoflares) may play significant a role in plasma heating in solar corona.

  15. Solar-energy absorber: Active infrared (IR) trap

    NASA Technical Reports Server (NTRS)

    Brantley, L. W., Jr.

    1974-01-01

    Efficiency of solar-energy absorbers may be improved to 95% by actively cooling their intermediate glass plates. This approach may be of interest to manufacturers of solar absorbers and to engineers and scientists developing new sources of energy.

  16. A complete solar eruption activity processing tool with robotization and real time (II)

    NASA Astrophysics Data System (ADS)

    Lin, Ganghua; Zhao, Cui; Yang, Xiao

    2014-07-01

    Intense solar active events have made significant impacts on the modern high technology system and living environment of human being, therefore solar activities forecast and space weather forecast are getting more and more attention. Meanwhile, data volume acquisitioned by solar monitor facility is growing larger and larger due to the requirement of multiple dimensions observation and high temporal and spatial resolution. As staffs of a solar monitor data producer, we are encouraged to adopt new techniques and methods to provide valuable information to solar activities forecast organization and the other related users, and provide convenient products and tools to the users. In the previous paper "A complete solar eruption activities processing tool with robotization and real time (I)", we presented a fully automatic and real time detecting architecture for different solar erupt activities. In this paper, we present new components of new data sets in the architecture design, latest progresses on automatic recognition of solar flare, filament and magnetic field, and a newly introduced method with which solar photospheric magnetic nonpotentiality parameters are processed in real time, then its result directly can be used in solar active forecast.

  17. Endothelial Dysfunction and Blood Viscosity Inpatients with Unstable Angina in Different Periods of a Solar Activity

    NASA Astrophysics Data System (ADS)

    Parshina, S. S.; Tokaeva, L. K.; Dolgova, E. M.; Afanas'yeva, T. N.; Strelnikova, O. A.

    The origin of hemorheologic and endothelial defects in patients with unstable angina (comparing with healthy persons) is determined by a solar activity period: the blood viscosity increases in a period of high solar activity in the vessels of small, medium and macro diameters, a local decompensate dysfunction of small vessels endothelium had been fixed (microcirculation area). In the period of a low solar activity there is an increase of a blood viscosity in vessels of all diameters, generalized subcompensated endothelial dysfunction is developed (on the background of the III phase blood clotting activating). In the period of a high solar activity a higher blood viscosity had been fixed, comparing with the period of a low solar activity.

  18. Magnetic helicity in emerging solar active regions

    SciTech Connect

    Liu, Y.; Hoeksema, J. T.; Bobra, M.; Hayashi, K.; Sun, X.; Schuck, P. W.

    2014-04-10

    Using vector magnetic field data from the Helioseismic and Magnetic Imager instrument aboard the Solar Dynamics Observatory, we study magnetic helicity injection into the corona in emerging active regions (ARs) and examine the hemispheric helicity rule. In every region studied, photospheric shearing motion contributes most of the helicity accumulated in the corona. In a sample of 28 emerging ARs, 17 follow the hemisphere rule (61% ± 18% at a 95% confidence interval). Magnetic helicity and twist in 25 ARs (89% ± 11%) have the same sign. The maximum magnetic twist, which depends on the size of an AR, is inferred in a sample of 23 emerging ARs with a bipolar magnetic field configuration.

  19. High-efficiency concentrator silicon solar cells

    SciTech Connect

    Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. . Solid-State Electronics Lab.)

    1990-11-01

    This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm{sup 2} cell with front grids achieved 26% efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

  20. Automatic Tracking of Active Regions and Detection of Solar Flares in Solar EUV Images

    NASA Astrophysics Data System (ADS)

    Caballero, C.; Aranda, M. C.

    2014-05-01

    Solar catalogs are frequently handmade by experts using a manual approach or semi-automated approach. The appearance of new tools is very useful because the work is automated. Nowadays it is impossible to produce solar catalogs using these methods, because of the emergence of new spacecraft that provide a huge amount of information. In this article an automated system for detecting and tracking active regions and solar flares throughout their evolution using the Extreme UV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft is presented. The system is quite complex and consists of different phases: i) acquisition and preprocessing; ii) segmentation of regions of interest; iii) clustering of these regions to form candidate active regions which can become active regions; iv) tracking of active regions; v) detection of solar flares. This article describes all phases, but focuses on the phases of tracking and detection of active regions and solar flares. The system relies on consecutive solar images using a rotation law to track the active regions. Also, graphs of the evolution of a region and solar evolution are presented to detect solar flares. The procedure developed has been tested on 3500 full-disk solar images (corresponding to 35 days) taken from the spacecraft. More than 75 % of the active regions are tracked and more than 85 % of the solar flares are detected.

  1. Solution Chemistry Engineering toward High-Efficiency Perovskite Solar Cells.

    PubMed

    Zhao, Yixin; Zhu, Kai

    2014-12-01

    Organic and inorganic hybrid perovskites (e.g., CH3NH3PbI3) have emerged as a revolutionary class of light-absorbing semiconductors that has demonstrated a rapid increase in efficiency within a few years of active research. Controlling perovskite morphology and composition has been found critical to developing high-performance perovskite solar cells. The recent development of solution chemistry engineering has led to fabrication of greater than 15-17%-efficiency solar cells by multiple groups, with the highest certified 17.9% efficiency that has significantly surpassed the best-reported perovskite solar cell by vapor-phase growth. In this Perspective, we review recent progress on solution chemistry engineering processes and various control parameters that are critical to the success of solution growth of high-quality perovskite films. We discuss the importance of understanding the impact of solution-processing parameters and perovskite film architectures on the fundamental charge carrier dynamics in perovskite solar cells. The cost and stability issues of perovskite solar cells will also be discussed. PMID:26278951

  2. Radio magnetography of the solar active regions

    NASA Astrophysics Data System (ADS)

    Gelfreikh, G. B.; Shibasaki, K.

    The observations of the solar magnetic fields is one of the most important basics for study of all important processes in structuring the solar atmosphere and most kinds of the release of the energy. The radio methods are of the special interest here because they gain the information on the magnetic field strength in the solar corona and upper chromosphere where traditional optical methods do not work. The construction of the Nobeyama radio heliograph opens a new era in usage radio methods for solar radio magnetography due to some unique property of the instrument: - The 2D mapping of the whole disk of the sun both in I and V Stokes parameters with resolution of 10 arcsec. - Regular observations (without breaks due to weather conditions), eight hours a day, already for seven years. The most effective and representative radio method of measuring the solar magnetic fields is to use polarization measurements of the thermal bremsstrahlung (free-free emission). It is applicable both to analysis of chromospheric and coronal magnetic fields and presents information on longitude component of the magnetic field strength in solar active regions. Three problems are met, however: (i) One needs to measure very low degree of polarization (small fraction of a percent); (ii) To get the real value of the field the spectral data are necessary. (iii) While observing an active region on the disk we have got the overlapping effects on polarized signal of the chromospheric and coronal magnetic fields. To get higher sensitivity the averaging of the radio maps over periods of about ten minutes were used with the results of sensitivity on V-maps of the order 0.1%. Observations for a number of dates have been analysed (August 22, 1992, October 31, 1992; June 30, 1993, July 22,1994, June 15, 1995 and some more). In all cases a very good similarity was found of the polarized regions (V-maps) with the Ca^ + plages in form and total coincidence with the direction of the magnetic fields on the

  3. Heat transparent high intensity high efficiency solar cell

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr. (Inventor)

    1982-01-01

    An improved solar cell design is described. A surface of each solar cell has a plurality of grooves. Each groove has a vertical face and a slanted face that is covered by a reflecting metal. Light rays are reflected from the slanted face through the vertical face where they traverse a photovoltaic junction. As the light rays travel to the slanted face of an adjacent groove, they again traverse the junction. The underside of the reflecting coating directs the light rays toward the opposite surface of solar cell as they traverse the junction again. When the light rays travel through the solar cell and reach the saw toothed grooves on the under side, the process of reflection and repeatedly traversing the junction again takes place. The light rays ultimately emerge from the solar cell. These solar cells are particularly useful at very high levels of insolation because the infrared or heat radiation passes through the cells without being appreciably absorbed to heat the cell.

  4. Composite Mg II solar activity index for solar cycles 21 and 22

    NASA Technical Reports Server (NTRS)

    Deland, Matthew T.; Cebula, Richard P.

    1993-01-01

    On the basis of version 1.0 of the composite MG II solar activity index data set, it is shown that the change in the 27-day running average of the Mg II index from solar maximum to solar minimum is about 8 percent for solar cycle 21 and about 9 percent for solar cycle 22 through January 1992. Scaling factors based on the short-term variations in the Mg II index and solar irradiance data sets are developed for each instrument to estimate solar variability at mid-UV and near-UV wavelengths. A set of composite scale factors are derived for use with the present composite MG index. Near 205 cm, where solar irradiance variations are important for stratospheric chemistry, the estimated change in irradiance during solar cycle 22 is about 10 +/- 1 percent using the composite Mg II index (version 1.0) and scale factors.

  5. Correlation of Doppler noise during solar conjunctions with fluctuations in solar activity

    NASA Technical Reports Server (NTRS)

    Berman, A. L.; Rockwell, S. T.

    1975-01-01

    Deviations betweeb observed Doppler noise and the noise model during solar conjunction were analyzed. It is tentatively concluded that these deviations are due to short-term fluctuations in solar activity as seen along the signal path, and not to solar/antenna structure effects or system noise temperature.

  6. On the solar activity variations of nocturnal F region vertical drifts covering two solar cycles in the Indian longitude sector

    NASA Astrophysics Data System (ADS)

    Madhav Haridas, M. K.; Manju, G.; Pant, Tarun Kumar

    2015-02-01

    A comprehensive analysis of the seasonal and solar cycle variabilities of nighttime vertical drift over the Indian longitude sector is accomplished using ionosonde data located at the magnetic equatorial location, Trivandrum (8.5°N, 76.5°E). The analysis extends over a span of two decades (1988-2008). The representative seasonal variations based on the extensive data of nocturnal vertical drift during three different solar activity epochs is arrived at, for the first time. Seasonally, it is seen that maximum post sunset Vd is obtained in vernal equinox (VE), followed by autumnal equinox (AE), winter solstice (WS), and summer solstice (SS) for high and moderate solar epochs, while for low solar epoch, maximum Vd occurs in WS followed by VE, AE, and SS. Further, the role of sunset times at the magnetic conjugate points in modulating the time and magnitude of peak drifts during different solar epochs is ascertained. The equinoctial asymmetry in peak Vd during high and moderate solar epochs is another significant outcome of this study. The solar activity dependence of vertical drift for a wide range of solar fluxes has been quantified for all the seasons. In the present era of GPS-based communication and navigation, these are important results that give a better handle in understanding essential factors that impact equatorial ionospheric phenomena.

  7. Modified Coronal Index of the Solar Activity

    NASA Astrophysics Data System (ADS)

    Lukáč, B.; Rybanský, M.

    2010-05-01

    The original coronal index of the solar activity (CI) has been constructed on the basis of ground-based measurements of the intensities of the coronal line of 530.3 nm (Rybanský in Bull. Astron. Inst. Czechoslov., 28, 367, 1975; Rybanský et al. in J. Geophys. Res., 110, A08106, 2005). In this paper, CI is compared with the EUV measurements on the CELIAS/SEM equipment based on the same idea as the original idea of the coronal index. The correlation is very good for the period 1996 - 2005 ( r=0.94 for daily values). The principal result of this paper is the introduction of the modified coronal index (MCI) which in all uses and contexts can replace the existing CI index. Daily MCI values extend over a time period of six solar activity cycles. Future MCI measurements will be derived from more reliable measurements made by space-based observatories that are not influenced by the weather. MCI measurements are and will continue to be archived at the web site of the Slovak Central Observatory in Hurbanovo ( http://www.suh.sk/obs/vysl/MCI.htm ).

  8. Long-term persistence of solar activity

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

    1994-01-01

    We examine the question of whether or not the non-periodic variations in solar activity are caused by a white-noise, random process. The Hurst exponent, which characterizes the persistence of a time series, is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD. We find a constant Hurst exponent, suggesting that solar activity in the frequency range from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately 0.8, is significantly larger than the value of 0.5 that would correspond to variations produced by a white-noise process. This value is in good agreement with the results for the monthly sunspot data reported elsewhere, indicating that the physics that produces the continuum is a correlated random process and that it is the same type of process over a wide range of time interval lengths.

  9. Solar Energy Education. Industrial arts: student activities. Field test edition

    SciTech Connect

    Not Available

    1981-02-01

    In this teaching manual several activities are presented to introduce students to information on solar energy through classroom instruction. Wind power is also included. Instructions for constructing demonstration models for passive solar systems, photovoltaic cells, solar collectors and water heaters, and a bicycle wheel wind turbine are provided. (BCS)

  10. Comparison of peak characteristics of the F2 ionospheric layer obtained from the Cyprus Digisonde and IRI-2012 model during low and high solar activity period

    NASA Astrophysics Data System (ADS)

    Haralambous, Haris; Oikonomou, Christina

    2015-11-01

    We investigate first the climatology expressed by diurnal and seasonal variations of the critical frequency (foF2) and the peak height (hmF2) of the F2-layer derived from digital ionosonde measurements at the low-middle latitude European station in Nicosia, Cyprus (geographical coordinates: 35°N, 33°E, geomagnetic lat. 29.38°N, I = 51.7°). Monthly median hourly values of the F2-layer peak characteristics are obtained using manually scaled data during the 5-year period 2009-2013. The observational results are then compared with the International Reference Ionospheric Model (IRI-2012) predictions using both URSI and CCIR coefficients. It is shown that the semi-annual pattern of daytime foF2 characterized by higher values at equinoxes than either solstices as well as the winter anomaly phenomenon demonstrate strong solar activity dependence. An annual pattern of night-time foF2 is also detected with lower values in winter and higher in summer. The seasonal variation of daytime hmF2 is evident and peaks of hmF2 at pre-sunrise and post-sunset hours are identified during December. The IRI-2012 model is capable to capture the main diurnal and seasonal patterns of foF2 and hmF2. The highest overestimation of daytime foF2 is noted at equinoxes and solstices except from March, October, December of 2011, and June of 2013. Significant foF2 underestimation is observed at evening and after midnight during February and March of 2009. Large positive discrepancies between the modeled and observed hmF2 values are noticed during the deep solar minimum year 2009. Overall, IRI-model estimates are more accurate for hmF2 than foF2 over Cyprus and for the examined period.

  11. Coronal Holes and Solar Wind High-Speed Streams: I. Forecasting the Solar Wind Parameters

    NASA Astrophysics Data System (ADS)

    Vršnak, Bojan; Temmer, Manuela; Veronig, Astrid M.

    2007-02-01

    We analyze the relationship between the coronal hole (CH) area/position and physical characteristics of the associated corotating high-speed stream (HSS) in the solar wind at 1 AU. For the analysis we utilize the data in the period DOY 25 125 of 2005, characterized by a very low coronal mass ejection (CME) activity. Distinct correlations between the daily averaged CH parameters and the solar wind characteristics are found, which allows us to forecast the solar wind velocity v, proton temperature T, proton density n, and magnetic field strength B, several days in advance in periods of low CME activity. The forecast is based on monitoring fractional areas A, covered by CHs in the meridional slices embracing the central meridian distance ranges [-40°,-20°], [-10°,10°], and [20°,40°]. On average, the peaks in the daily values of n, B, T, and v appear delayed by 1, 2, 3, and 4 days, respectively, after the area A attains its maximum in the central-meridian slice. The peak values of the solar wind parameters are correlated to the peak values of A, which provides also forecasting of the peak values of n, B, T, and v. The most accurate prediction can be obtained for the solar wind velocity, for which the average relative difference between the calculated and the observed peak values amounts to overline{\\vertδ\\vert}≈10 %. The forecast reliability is somewhat lower in the case of T, B, and n ( overline{\\vertδ\\vert}≈20 , 30, and 40%, respectively). The space weather implications are discussed, including the perspectives for advancing the real-time calculation of the Sun Earth transit times of coronal mass ejections and interplanetary shocks, by including more realistic real-time estimates of the solar wind characteristics.

  12. Solar-terrestrial predictions proceedings. Volume 4: Prediction of terrestrial effects of solar activity

    NASA Technical Reports Server (NTRS)

    Donnelly, R. E. (Editor)

    1980-01-01

    Papers about prediction of ionospheric and radio propagation conditions based primarily on empirical or statistical relations is discussed. Predictions of sporadic E, spread F, and scintillations generally involve statistical or empirical predictions. The correlation between solar-activity and terrestrial seismic activity and the possible relation between solar activity and biological effects is discussed.

  13. Magnetic observations during the recent declining phase of solar activity

    NASA Astrophysics Data System (ADS)

    Smith, E. J.

    Changes in the heliospheric magnetic field during the recent declining phase in solar activity are reviewed and compared with observations during past sunspot cycles. The study is based principally on data obtained by IMP-8 and Ulysses. The field magnitude is found to have increased during the declining phase until it reached a maximum value of 11.5nT in approximately 1991.5, approximately two years after sunspot maximum. The field of the sun's south pole became negative after a reversal in early 1990. The sector structure disappeared at Ulysses in April 1993 when the latitude of the spacecraft was -30 deg revealing a low inclination of the heliospheric current sheet. A large outburst of solar activity in March 1991 caused four Coronal Mass Ejections (CMEs) and numerious shocks at the location of Ulysses. Following a delay of more than a year, a series of recurrent high speed streams and Corotating Interaction Regions commenced in July 1992 which were observed by IMP-8, Ulysses and Voyager 2. In all these respects, the behavior of the magnetic field mimics that seen in the two earlier sunspot cycles. The comprehensive data set suggests a correlation between the absolute value of B and sunspot number. The major solar cycle variations in the radial component (and magnitude) of the field have been successfully reproduced by a recent model consisting of a tilted solar dipole, whose strength and tilt undergo characteristic changes over the sunspot cycle, and the heliospheric current sheet. The large outbursts of activity in mid-1972, mid-1982 and the first quarter of 1991 may represent a characteristic last 'gasp' of solar activity before the sun evolves to a different state. The recurrent high speed streams in 1973, 1984 and 1992 accompany the developemnt of large asymetrical polar coronal holes and the growth in intensity of the polar cap fields. After they endure for about one year, the polar coronal holes recede and the high speed streams are replaced by weaker

  14. Magnetic observations during the recent declining phase of solar activity

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    Changes in the heliospheric magnetic field during the recent declining phase in solar activity are reviewed and compared with observations during past sunspot cycles. The study is based principally on data obtained by IMP-8 and Ulysses. The field magnitude is found to have increased during the declining phase until it reached a maximum value of 11.5nT in approximately 1991.5, approximately two years after sunspot maximum. The field of the sun's south pole became negative after a reversal in early 1990. The sector structure disappeared at Ulysses in April 1993 when the latitude of the spacecraft was -30 deg revealing a low inclination of the heliospheric current sheet. A large outburst of solar activity in March 1991 caused four Coronal Mass Ejections (CMEs) and numerious shocks at the location of Ulysses. Following a delay of more than a year, a series of recurrent high speed streams and Corotating Interaction Regions commenced in July 1992 which were observed by IMP-8, Ulysses and Voyager 2. In all these respects, the behavior of the magnetic field mimics that seen in the two earlier sunspot cycles. The comprehensive data set suggests a correlation between the absolute value of B and sunspot number. The major solar cycle variations in the radial component (and magnitude) of the field have been successfully reproduced by a recent model consisting of a tilted solar dipole, whose strength and tilt undergo characteristic changes over the sunspot cycle, and the heliospheric current sheet. The large outbursts of activity in mid-1972, mid-1982 and the first quarter of 1991 may represent a characteristic last 'gasp' of solar activity before the sun evolves to a different state. The recurrent high speed streams in 1973, 1984 and 1992 accompany the developemnt of large asymetrical polar coronal holes and the growth in intensity of the polar cap fields. After they endure for about one year, the polar coronal holes recede and the high speed streams are replaced by weaker

  15. The magnetic field structure in the active solar corona.

    NASA Technical Reports Server (NTRS)

    Schatten, K. H.

    1971-01-01

    The structure of the magnetic field of the active solar corona is discussed with reference to optical and radio observations of the solar atmosphere. Eclipse observations provide evidence of fine scale structures in the solar atmosphere that appear to relate to the coronal magnetic field. The coronal magnetic field used for comparison is calculated from potential theory; the influence of solar activity upon the potential theory field is discussed with reference to observations of the Faraday rotation of a microwave signal from Pioneer 6 as it was occulted by the solar atmosphere. Evidence has been found suggesting the existence of expanding magnetic bottles located at 10 solar radii above flaring active regions. The dynamics of these events is discussed. It is further suggested that these magnetic bottles are an important component in the solar corona.

  16. Applications of nonimaging optics for very high solar concentrations

    SciTech Connect

    O`Gallagher, J.; Winston, R.

    1997-12-31

    Using the principles and techniques of nonimaging optics, solar concentrations that approach the theoretical maximum can be achieved. This has applications in solar energy collection wherever concentration is desired. In this paper, we survey recent progress in attaining and using high and ultrahigh solar fluxes. We review a number of potential applications for highly concentrated solar energy and the current status of the associated technology. By making possible new and unique applications for intense solar flux, these techniques have opened a whole new frontier for research and development of potentially economic uses of solar energy.

  17. High efficiency crystalline silicon solar cells

    NASA Technical Reports Server (NTRS)

    Sah, C. Tang

    1986-01-01

    A review of the entire research program since its inception ten years ago is given. The initial effort focused on the effects of impurities on the efficiency of silicon solar cells to provide figures of maximum allowable impurity density for efficiencies up to about 16 to 17%. Highly accurate experimental techniques were extended to characterize the recombination properties of the residual imputities in the silicon solar cell. A numerical simulator of the solar cell was also developed, using the Circuit Technique for Semiconductor Analysis. Recent effort focused on the delineation of the material and device parameters which limited the silicon efficiency to below 20% and on an investigation of cell designs to break the 20% barrier. Designs of the cell device structure and geometry can further reduce recombination losses as well as the sensitivity and criticalness of the fabrication technology required to exceed 20%. Further research is needed on the fundamental characterization of the carrier recombination properties at the chemical impurity and physical defect centers. It is shown that only single crystalline silicon cell technology can be successful in attaining efficiencies greater than 20%.

  18. High-Temperature High-Efficiency Solar Thermoelectric Generators

    SciTech Connect

    Baranowski, LL; Warren, EL; Toberer, ES

    2014-03-01

    Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

  19. Significantly high wave trains in cosmic rays and solar radio flux

    NASA Astrophysics Data System (ADS)

    Mishra, Rajesh Kumar; Agarwal, Rekha

    2016-07-01

    Magnetic field of the Sun disturbs the propagation of cosmic rays during their propagation through the Heliosphere, and introduces variations on time scales that range from hours to millennia. Changes in the heliosphere arising from fluctuations in the Sun's magnetic field mean that galactic cosmic rays are less able to reach the Earth when the Sun is more active so the cosmic ray flux is inversely related to solar activity. In the present work studies has been carried on the occurrence of a large number high amplitude wave train events in cosmic ray intensity and to identify a possible dependence on 10.7-cm solar radio flux (solar activity) using the hourly cosmic ray neutron monitor data for two different ground based neutron monitors. The phase for both high amplitude events as well as for all days is found to significantly deviate towards an earlier hour as compared to the corotational/azimuthal direction. The amplitude of first harmonic and 10.7-cm solar radio flux significantly deviates and reaches to its peak and phase remains in the corotational direction during the years close to solar activity maximum for these high amplitude events. The occurrence of high amplitude wave train events is dominant during solar activity minimum as well as maximum years. The amplitude as well as phase of the first harmonic of cosmic ray intensity during high amplitude events shows significant correlation with solar activity. However, the frequency of occurrence of high amplitude events shows a very nominal dependence on solar activity. Keywords: high amplitude wave trains, cosmic ray, solar activity, 10.7-cm solar radio flux, magnetic field.

  20. The solar atmosphere and the structure of active regions. [aircraft accidents, weather

    NASA Technical Reports Server (NTRS)

    Sturrock, P. A.

    1975-01-01

    Numerical analyses of solar activities are presented. The effect of these activities on aircraft and weather conditions was studied. Topics considered are: (1) solar flares; (2) solar X-rays; and (3) solar magnetic fields (charts are shown).

  1. Limits of Predictability of Solar Activity

    NASA Astrophysics Data System (ADS)

    Kremliovsky, M. N.

    1995-07-01

    The study of a nonlinear chaotic map of 11-year cycle maxima evolution recently derived from observations is presented with the purpose of predicting the features of the long-term variability of solar activity. It is stressed that dynamical forecast is limited by the Lyapunov time and a statistical approach can be justified due to the ergodic properties of the chaotic evolution. The Gleissberg variation is described as a chaotic walk and its distribution over length is shown to be broad. The global minima are identified as laminar slots of temporal intermittency and their typical distribution over length is also given. We note that a long sunspot cycle can be used as a precursor of the global minimum and a close sequence of global minima (once in approximately 1500 2000 years) may be responsible for the climatic changes (Little Ice Ages).

  2. Active Vibration Damping of Solar Arrays

    NASA Astrophysics Data System (ADS)

    Reinicke, Gunar; Baier, Horst; Grillebeck, Anton; Scharfeld, Frank; Hunger, Joseph; Abou-El-Ela, A.; Lohberg, Andreas

    2012-07-01

    Current generations of large solar array panels are lightweight and flexible constructions to reduce net masses. They undergo strong vibrations during launch. The active vibration damping is one convenient option to reduce vibration responses and limit stresses in facesheets. In this study, two actuator concepts are used for vibration damping. A stack interface actuator replaces a panel hold down and is decoupled from bending moments and shear forces. Piezoelectric patch actuators are used as an alternative, where the number, position and size of actuators are mainly driven by controllability analyses. Linear Quadratic Gaussian control is used to attenuate vibrations of selected mode shapes with both actuators. Simulations as well as modal and acoustic tests show the feasibility of selected actuator concepts.

  3. Determination of solar proton fluxes and energies at high solar latitudes by UV radiation measurements

    NASA Technical Reports Server (NTRS)

    Witt, N.; Blum, P. W.; Ajello, J. M.

    1981-01-01

    The latitudinal variation of the solar proton flux and energy causes a density increase at high solar latitudes of the neutral gas penetrating the heliosphere. Measurements of the neutral density by UV resonance radiation observations from interplanetary spacecraft thus permit deductions on the dependence of the solar proton flux on heliographic latitude. Using both the results of Mariner 10 measurements and of other off-ecliptic solar wind observations, the values of the solar proton fluxes and energies at polar heliographic latitudes are determined for several cases of interest. The Mariner 10 analysis, together with IPS results, indicate a significant decrease of the solar proton flux at polar latitudes.

  4. Solar Activity Forecasting for use in Orbit Prediction

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth

    2001-01-01

    Orbital prediction for satellites in low Earth orbit (LEO) or low planetary orbit depends strongly on exospheric densities. Solar activity forecasting is important in orbital prediction, as the solar UV and EUV inflate the upper atmospheric layers of the Earth and planets, forming the exosphere in which satellites orbit. Geomagnetic effects also relate to solar activity. Because of the complex and ephemeral nature of solar activity, with different cycles varying in strength by more than 100%, many different forecasting techniques have been utilized. The methods range from purely numerical techniques (essentially curve fitting) to numerous oddball schemes, as well as a small subset, called 'Precursor techniques.' The situation can be puzzling, owing to the numerous methodologies involved, somewhat akin to the numerous ether theories near the turn of the last century. Nevertheless, the Precursor techniques alone have a physical basis, namely dynamo theory, which provides a physical explanation for why this subset seems to work. I discuss this solar cycle's predictions, as well as the Sun's observed activity. I also discuss the SODA (Solar Dynamo Amplitude) index, which provides the user with the ability to track the Sun's hidden, interior dynamo magnetic fields. As a result, one may then update solar activity predictions continuously, by monitoring the solar magnetic fields as they change throughout the solar cycle. This paper ends by providing a glimpse into what the next solar cycle (#24) portends.

  5. High voltage planar multijunction solar cell

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr.; Chai, A. T.; Goradia, C. P. (Inventor)

    1982-01-01

    A high voltage multijunction solar cell is provided wherein a plurality of discrete voltage generating regions or unit cells are formed in a single generally planar semiconductor body. The unit cells are comprised of doped regions of opposite conductivity type separated by a gap or undiffused region. Metal contacts connect adjacent cells together in series so that the output voltages of the individual cells are additive. In some embodiments, doped field regions separated by a overlie the unit cells but the cells may be formed in both faces of the wafer.

  6. Growth and Decay of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Dobias, J. J.; Chapman, G. A.; Cookson, A. M.; Preminger, D. G.; Walton, S. R.

    2002-05-01

    We report here on a study of growth and decay rates of sunspot and facular areas of solar active regions. The data used in this project come from an ongoing program of daily photometric observations of the sun with the Cartesian Full Disk Telescope No. 1 (CFDT1) at the San Fernando Observatory (SFO). Sunspot regions are determined from images taken with a red filter centered at 672.3 nm with a bandpass of 9.7 nm, while images taken with a Ca II K line filter, centered at 393.4 nm and with a bandpass of only 1nm, are used to find facular areas. Before any areas can be found on any observed images, they have to be calibrated then flattened by removing limb darkening thus producing contrast images. Sunspot areas are then determined from any pixel with contrast of -8.5% or less, while any pixel on a K line contrast image with a contrast of +4.8%/μ or higher, where μ is the cosine of the heliocentric angle, is considered to be a facular pixel. To identify the areas as clearly as possible, studied active regions were usually observed on the sun with relatively low activity; that means that each region is either alone on the sun's disk or with only very few other active regions present. Furthermore, to obtain growth and decay patterns of the areas as reliably as possible, only such active regions must be chosen for which there is as complete observational coverage as possible. At the present time studies have been finished for only a few active regions, but analysis of several others is on going. Obtained results will be presented at the meeting. This work is supported by NSF grant ATM-9912132 and NASA grants NAG5-7191 and NAG5-7778.

  7. Solar activity during the deep minimum of 2009

    NASA Astrophysics Data System (ADS)

    Sylwester, Janusz; Siarkowski, Marek; Gburek, Szymon; Gryciuk, Magdalena; Kepa, Anna; Kowaliński, Mirosław; Mrozek, Tomek; Phillips, Kenneth J. H.; Podgórski, Piotr; Sylwester, Barbara

    2014-12-01

    We discuss the character of the unusually deep solar activity minimum of 2009 between Solar Cycles 23 and 24. Levels of solar activity in various parts of the solar atmosphere -- photosphere, chromosphere, transition region, and corona -- were observed to be at their lowest for a century. The soft X-ray emission from the corona (hot outer part of the Sun's atmosphere) was measured throughout most of 2009 with the Polish-built SphinX spectrophotometer. Unlike other X-ray monitoring spacecraft, this sensitive spacecraft-borne instrument was able to continue measurements throughout this extended period of low activity.

  8. Orbiting solar observatory 8 high resolution ultraviolet spectrometer experiment

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Oscillations, physical properties of the solar atmosphere, motions in the quiet solar atmosphere, coronal holes, motions in solar active regions, solar flares, the structure of plage regions, an atlas, and aeronomy are summarized. Photometric sensitivity, scattered light, ghosts, focus and spectral resolution, wavelength drive, photometric sensitivity, and scattered light, are also summarized. Experiments are described according to spacecraft made and experiment type. Some of the most useful data reduction programs are described.

  9. Spring-fall asymmetry of substorm strength, geomagnetic activity and solar wind: Implications for semiannual variation and solar hemispheric asymmetry

    USGS Publications Warehouse

    Mursula, K.; Tanskanen, E.; Love, J.J.

    2011-01-01

    We study the seasonal variation of substorms, geomagnetic activity and their solar wind drivers in 1993-2008. The number of substorms and substorm mean duration depict an annual variation with maxima in Winter and Summer, respectively, reflecting the annual change of the local ionosphere. In contradiction, substorm mean amplitude, substorm total efficiency and global geomagnetic activity show a dominant annual variation, with equinoctial maxima alternating between Spring in solar cycle 22 and Fall in cycle 23. The largest annual variations were found in 1994 and 2003, in the declining phase of the two cycles when high-speed streams dominate the solar wind. A similar, large annual variation is found in the solar wind driver of substorms and geomagnetic activity, which implies that the annual variation of substorm strength, substorm efficiency and geomagnetic activity is not due to ionospheric conditions but to a hemispherically asymmetric distribution of solar wind which varies from one cycle to another. Our results imply that the overall semiannual variation in global geomagnetic activity has been seriously overestimated, and is largely an artifact of the dominant annual variation with maxima alternating between Spring and Fall. The results also suggest an intimate connection between the asymmetry of solar magnetic fields and some of the largest geomagnetic disturbances, offering interesting new pathways for forecasting disturbances with a longer lead time to the future. Copyright ?? 2011 by the American Geophysical Union.

  10. Spring-fall asymmetry of substorm strength, geomagnetic activity and solar wind: Implications for semiannual variation and solar hemispheric asymmetry

    USGS Publications Warehouse

    Marsula, K.; Tanskanen, E.; Love, J.J.

    2011-01-01

    We study the seasonal variation of substorms, geomagnetic activity and their solar wind drivers in 1993–2008. The number of substorms and substorm mean duration depict an annual variation with maxima in Winter and Summer, respectively, reflecting the annual change of the local ionosphere. In contradiction, substorm mean amplitude, substorm total efficiency and global geomagnetic activity show a dominant annual variation, with equinoctial maxima alternating between Spring in solar cycle 22 and Fall in cycle 23. The largest annual variations were found in 1994 and 2003, in the declining phase of the two cycles when high-speed streams dominate the solar wind. A similar, large annual variation is found in the solar wind driver of substorms and geomagnetic activity, which implies that the annual variation of substorm strength, substorm efficiency and geomagnetic activity is not due to ionospheric conditions but to a hemispherically asymmetric distribution of solar wind which varies from one cycle to another. Our results imply that the overall semiannual variation in global geomagnetic activity has been seriously overestimated, and is largely an artifact of the dominant annual variation with maxima alternating between Spring and Fall. The results also suggest an intimate connection between the asymmetry of solar magnetic fields and some of the largest geomagnetic disturbances, offering interesting new pathways for forecasting disturbances with a longer lead time to the future.

  11. Solar Irradiance Variations on Active Region Time Scales

    NASA Technical Reports Server (NTRS)

    Labonte, B. J. (Editor); Chapman, G. A. (Editor); Hudson, H. S. (Editor); Willson, R. C. (Editor)

    1984-01-01

    The variations of the total solar irradiance is an important tool for studying the Sun, thanks to the development of very precise sensors such as the ACRIM instrument on board the Solar Maximum Mission. The largest variations of the total irradiance occur on time scales of a few days are caused by solar active regions, especially sunspots. Efforts were made to describe the active region effects on total and spectral irradiance.

  12. Solar air-conditioning-active, hybrid and passive

    SciTech Connect

    Yellott, J. I.

    1981-04-01

    After a discussion of summer air conditioning requirements in the United States, active, hybrid, and passive cooling systems are defined. Active processes and systems include absorption, Rankine cycle, and a small variety of miscellaneous systems. The hybrid solar cooling and dehumidification technology of desiccation is covered as well as evaporative cooling. The passive solar cooling processes covered include convective, radiative and evaporative cooling. Federal and state involvement in solar cooling is then discussed. (LEW)

  13. High-power, ultralow-mass solar arrays: FY-77 solar arrays technology readiness assessment report, volume 2

    NASA Technical Reports Server (NTRS)

    Costogue, E. N.; Young, L. E.; Brandhorst, H. W., Jr.

    1978-01-01

    Development efforts are reported in detail for: (1) a lightweight solar array system for solar electric propulsion; (2) a high efficiency thin silicon solar cell; (3) conceptual design of 200 W/kg solar arrays; (4) fluorocarbon encapsulation for silicon solar cell array; and (5) technology assessment of concentrator solar arrays.

  14. Development of a system for accurate forecasting of solar activity. Final report, 15 Oct 87-14 Oct 90

    SciTech Connect

    Sofia, S.

    1991-07-11

    This is a continuing effort which has empirical, theoretical and experimental components related to the physics of solar activity. The empirical forecasting scheme, developed under this grant, has been very successful for solar cycle 22. Important elements of a highly sophisticated theoretical scheme to model the solar activity cycle have been produced and tested. The Solar Disk Sextant experiment is progressing well. In addition to the Principal Investigator, this work involves five students and two research associates.

  15. Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

    SciTech Connect

    Dinetta, L.C.; Hannon, M.H.

    1995-10-01

    Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  18. New high-efficiency silicon solar cells

    NASA Technical Reports Server (NTRS)

    Daud, T.; Crotty, G. T.

    1985-01-01

    A design for silicon solar cells was investigated as an approach to increasing the cell open-circuit voltage and efficiency for flat-plate terrestrial photovoltaic applications. This deviates from past designs, where either the entire front surface of the cell is covered by a planar junction or the surface is textured before junction formation, which results in an even greater (up to 70%) junction area. The heavily doped front region and the junction space charge region are potential areas of high recombination for generated and injected minority carriers. The design presented reduces junction area by spreading equidiameter dot junctions across the surface of the cell, spaced about a diffusion length or less from each other. Various dot diameters and spacings allowed variations in total junction area. A simplified analysis was done to obtain a first-order design optimization. Efficiencies of up to 19% can be obtained. Cell fabrication involved extra masking steps for selective junction diffusion, and made surface passivation a key element in obtaining good collection. It also involved photolithography, with line widths down to microns. A method is demonstrated for achieving potentially high open-circuit voltages and solar-cell efficiencies.

  19. Impact of High Solar Penetration in the Western Interconnection

    SciTech Connect

    Lew, D.; Miller, N.; Clark, K.; Jordan, G.; Gao, Z.

    2010-12-01

    This paper presents an overview of the variable characteristics of solar power, as well as the accompanying grid dynamic performance and operational economics for a system with significant solar generation. The paper will show results of economic operational simulations of a very high solar generation future for the western half of the United States.

  20. Near-Earth Solar Wind Flows and Related Geomagnetic Activity During more than Four Solar Cycles (1963-2011)

    NASA Technical Reports Server (NTRS)

    Richardson, Ian G.; Cane, Hilary V.

    2012-01-01

    In past studies, we classified the near-Earth solar wind into three basic flow types based on inspection of solar wind plasma and magnetic field parameters in the OMNI database and additional data (e.g., geomagnetic indices, energetic particle, and cosmic ray observations). These flow types are: (1) High-speed streams associated with coronal holes at the Sun, (2) Slow, interstream solar wind, and (3) Transient flows originating with coronal mass ejections at the Sun, including interplanetary coronal mass ejections and the associated upstream shocks and post-shock regions. The solar wind classification in these previous studies commenced with observations in 1972. In the present study, as well as updating this classification to the end of 2011, we have extended the classification back to 1963, the beginning of near-Earth solar wind observations, thereby encompassing the complete solar cycles 20 to 23 and the ascending phase of cycle 24. We discuss the cycle-to-cycle variations in near-Earth solar wind structures and l1e related geomagnetic activity over more than four solar cycles, updating some of the results of our earlier studies.

  1. Overview of the Temperature Response in the Mesosphere and Lower Thermosphere to Solar Activity

    NASA Technical Reports Server (NTRS)

    Beig, Gufran; Scheer, Juergen; Mlynczak, Martin G.; Keckhut, Philippe

    2008-01-01

    The natural variability in the terrestrial mesosphere needs to be known to correctly quantify global change. The response of the thermal structure to solar activity variations is an important factor. Some of the earlier studies highly overestimated the mesospheric solar response. Modeling of the mesospheric temperature response to solar activity has evolved in recent years, and measurement techniques as well as the amount of data have improved. Recent investigations revealed much smaller solar signatures and in some case no significant solar signal at all. However, not much effort has been made to synthesize the results available so far. This article presents an overview of the energy budget of the mesosphere and lower thermosphere (MLT) and an up-to-date status of solar response in temperature structure based on recently available observational data. An objective evaluation of the data sets is attempted and important factors of uncertainty are discussed.

  2. Periods of High Intensity Solar Proton Flux

    NASA Technical Reports Server (NTRS)

    Xapsos, Michael A.; Stauffer, Craig A.; Jordan, Thomas M.; Adams, James H.; Dietrich, William F.

    2012-01-01

    Analysis is presented for times during a space mission that specified solar proton flux levels are exceeded. This includes both total time and continuous time periods during missions. Results for the solar maximum and solar minimum phases of the solar cycle are presented and compared for a broad range of proton energies and shielding levels. This type of approach is more amenable to reliability analysis for spacecraft systems and instrumentation than standard statistical models.

  3. High voltage series connected tandem junction solar battery

    DOEpatents

    Hanak, Joseph J.

    1982-01-01

    A high voltage series connected tandem junction solar battery which comprises a plurality of strips of tandem junction solar cells of hydrogenated amorphous silicon having one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon, arranged in a tandem configuration, can have the same bandgap or differing bandgaps. The tandem junction strip solar cells are series connected to produce a solar battery of any desired voltage.

  4. A statistic study of ionospheric solar flare activity indicator

    NASA Astrophysics Data System (ADS)

    Xiong, Bo; Ding, Feng; Ning, Baiqi; Wan, Weixing; Yu, You; Hu, Lianhuan

    According to the Chapman ionization theory, an ionospheric solar flare activity indicator (ISFAI) is given by the solar zenith angle and the variation rate of ionospheric vertical total electron content, which is measured from a global network of dual-frequency GPS receivers. The ISFAI is utilized to statistically analyze the ionospheric responses to 1439 M-class and 126 X-class solar flares during solar cycle 23 (1996-2008). The statistical results show that the occurrence of ISFAI peak increases obviously at 3.2 total electron content unit (TECU)/h (1 TECU = 1016 elm-2) and reaches the maximum at 10 TECU/h during M-class flares and 10 TECU/h and 40 TECU/h for X-class flares. ISFAI is closely correlated with the 26-34 nm extreme ultraviolet flux but poorly related to the 0.1-0.8 nm X-ray flux. The central meridian distance (CMD) of flare location is an important reason for depressing relationship between ISFAI and X-ray Flux. Through the CMD effect modification, the ISFAI has a significant dependence on the X-ray flux with a correlation coefficient of 0.76. The ISFAI sensitivity enables to detect the extreme X-class flares, as well as the variations of one order of magnitude or even smaller (such as for C-class flares). Meanwhile, ISFAI is helpful to the calibration of the X-ray flux at 0.1-0.8 nm observed by GOES during some flares. In addition, statistical results demonstrate that ISFAI can detect 80% of all M-class flares and 92% for all X-class ones during 1996-2008. Owing to the high sensitivity and temporal resolution, ISFAI can be utilized as a solar flare detection parameter to monitor space weather.

  5. Solar Forecasting Challenges and Opportunities for Enabling High Penetration of Solar Energy

    NASA Astrophysics Data System (ADS)

    Mishra, S.

    2015-12-01

    In 2011, DOE launched the SunShot Initiative to reduce the total cost of solar energy systems by about 75% to make them cost competitive with other forms of energy (without subsidies) by 2020. This translates to a total cost of installed solar energy at 1/Watt or 0.06/kWh, incentivizing high penetration of solar on the utility grid. In the past four years, the SunShot Initiative has catalyzed revolutionary advancements in solar technologies, stimulating significant growth and accelerating deployment of solar energy systems. However, as solar deployment increases, integrating solar energy into the utility grid poses difficult challenges due to the variability in solar resource and the impact of clouds and aerosols on surface irradiance. Accurate forecasting of solar resource and its variability at high temporal and spatial resolution at least a day ahead is crucial to large scale integration of solar energy into the utility grid. However, this is limited by current errors in forecasting that are as high as 25% for clear sky forecasts of Global Horizontal Irradiance (GHI), and as large as 40-80% for cloudy conditions. Forecasting errors are even higher for the direct normal irradiance (DNI). For solar energy to be seamlessly integrated into the utility grid under the scenarios of high penetration of solar, significant improvements in surface solar irradiance modeling and observations of both Global Horizontal Irradiance (GHI) and Direct Normal Irradiance (DNI) are essential to accurately predict power outputs from photovoltaic (PV) and concentrating solar power (CSP) systems. Furthermore, forecasting improvements have to be closely tied to utility needs and operation timelines. Details about the ongoing research efforts supported through the SunShot initiative and the challenges and needs for solar forecasting improvements in regards to the SunShot Initiative will be presented at the conference.

  6. Real Research In The Classroom - Solar Active Longitudes

    NASA Astrophysics Data System (ADS)

    Stagg, T.; Gearen, M.; Jacoby, S. H.; Jones, H. P.; Henney, C. J.; Hill, F.

    2000-12-01

    We present a high-school level educational/research module for a project that improves computer and analytical skills and contributes new scientific results to the field of solar astronomy and physics. The module has been developed within the RET (Research Experience for Teachers) program as a new application of a cooperative project between the RBSE (Research-Based Science Education) initiative of the NSF and the NASA Education/Public Outreach program. The research goal is to improve our knowledge of the characteristics of solar active longitudes, where sunspots tend to cluster. In particular, the rotation rate of these regions is poorly known. It is suspected that the active longitude rotation rate (ALRR) is different from the rotation rate of the solar surface. If this is true, the ALRR can be compared with the internal rotation rate deduced by helioseismology providing an estimate of the active region depth. A good determination of the ALRR requires the measurement of the position of thousands of individual active regions, a step best done by interactive examination of images, selection of regions, and determination of heliographic position. These tasks are well-suited for high school students, who are thus provided with a motivation to improve their computer and scientific thinking skills. ScionImage (PC)/NIH Image (Macs) macros for this purpose have been developed which access a CD-ROM of 25 years of NSO/Kitt Peak magnetogram data and laboratory exercises developed previously for classroom use. In the future, a web site will be created for collecting the data from classrooms across the US, and for status reports on the results.

  7. Analytical Study of Geomagnetic and Solar Activities During Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Hady, A. A.

    The data of amplitude and phase of most common indicators of geomagnetic activities (especially aa index, A? index) have been analyzed and compared with the solar ac- tivities in the time of solar cycle 23(started from 1996 to 2007). The data taken from NOAA space environment center (SES), USA. during the period starting April 1996 Until Dec. 2001, have been analyzed by power spectrum method. The prediction until year 2007 of geomagnetic activities were studied according to the whole of behavior of solar cycle 23. The results show a good indication of the effects of solar activities on changes of earth climate and weather forecasting. The results are important to various techniques including the operation of low earth orbiting satellites. The climatologi- cal approach makes use of the secular trend since year 1900 until now, by about 15 nanotesla. This indication was recorded too, in solar activity changes during the last century.

  8. Multi-wavelength solar activity complexes evolution from Solar Dynamic Observatory (SDO)

    NASA Astrophysics Data System (ADS)

    Korolkova, Olga; Benevolenskaya, Elena

    The main problem of the solar physics is to understand a nature of the solar magnetic activity. New space missions and background observations provide us by data describing solar activity with a good space and time resolution. Space missions data observe the solar activity in multi-wavelength emissions come from photosphere to corona. The complex of the solar activity has roots in inte-rior and extends to the solar corona. Thus, modern data give an opportunity to study the activity on the Sun at different levels simultaneously. Solar Dynamics Observatory (SDO) [1] which launched at the beginning of 2010, looks at Sun in different wavelengths such as coronal lines 171Å & 335Å. Also SDO measures photospheric magnetic flux (line-of-sight component of the magnetic field strength) and gives images in continuum. We have studied a stable complexes of the solar activity (about 30 com-plexes) during 6 hours from 10 March 2013 to 14 October 2013 using 720s ca-dence of HMI (Helioseismic and Magnetic Imager) [2] and AIA (Atmospheric Imaging Assembly) [3] instruments of SDO. We have found a good relationship between the magnetic flux and coronal emissions. Here we discuss properties of the complexes in the different levels from photosphere to corona. References 1. W. Dean Pesnell, B.J. Thompson, P.C. Chamberlin // Solar Phys., v. 275, p. 3-15, (2012). 2. P.H. Scherrer, J. Schou, R.I. Bush et al. // Solar Phys., v. 275, p. 207-227, (2012). 3. James R. Lemen • Alan M. Title • David J. Akin et al. // Solar Phys., v. 275, p. 17-40, (2012).

  9. New vacuum solar telescope and observations with high resolution

    NASA Astrophysics Data System (ADS)

    Liu, Zhong; Xu, Jun; Gu, Bo-Zhong; Wang, Sen; You, Jian-Qi; Shen, Long-Xiang; Lu, Ru-Wei; Jin, Zhen-Yu; Chen, Lin-Fei; Lou, Ke; Li, Zhi; Liu, Guang-Qian; Xu, Zhi; Rao, Chang-Hui; Hu, Qi-Qian; Li, Ru-Feng; Fu, Hao-Wen; Wang, Feng; Bao, Men-Xian; Wu, Ming-Chan; Zhang, Bo-Rong

    2014-06-01

    The New Vacuum Solar Telescope (NVST) is a one meter vacuum solar telescope that aims to observe fine structures on the Sun. The main goals of NVST are high resolution imaging and spectral observations, including measurements of the solar magnetic field. NVST is the primary ground-based facility used by the Chinese solar research community in this solar cycle. It is located by Fuxian Lake in southwest China, where the seeing is good enough to perform high resolution observations. We first introduce the general conditions at the Fuxian Solar Observatory and the primary science cases of NVST. Then, the basic structures of this telescope and instruments are described in detail. Finally, some typical high resolution data of the solar photosphere and chromosphere are also shown.

  10. Bayesian Infernce for Indentifying Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Pap, Judit; Turmon, Michael; Mukhtar, Saleem

    1997-01-01

    The solar chromosphere consists of three classes-- plage, network, background -- which contribute differently to ultraviolet radiation reaching the earth. Solar physicists are interested in relating plage area and intensity to UV irradiance, as well as understanding the spatial and temporal evolution of plage shapes.

  11. Heliospheric Consecuences of Solar Activity In Several Interplanetary Phenomena

    NASA Astrophysics Data System (ADS)

    Valdés-Galicia, J. F.; Mendoza, B.; Lara, A.; Maravilla, D.

    We have done an analysis of several phenomena related to solar activity such as the total magnetic flux, coronal hole area and sunspots, investigated its long trend evolu- tion over several solar cycles and its possible relationships with interplanetary shocks, sudden storm commencements at earth and cosmic ray variations. Our results stress the physical connection between the solar magnetic flux emergence and the interplan- etary medium dynamics, in particular the importance of coronal hole evolution in the structuring of the heliosphere.

  12. High resolution solar X-ray studies

    NASA Technical Reports Server (NTRS)

    Blake, R. L.

    1974-01-01

    Two high resolution solar X-ray payloads and their launches on Aerobee rockets with pointing system are described. The payloads included 5 to 25A X-ray spectrometers, multiaperture X-ray cameras, and command box attitude control inflight by means of a television image radioed to ground. Spatial resolution ranged from five arc minutes to ten arc seconds and spectral resolution ranged from 500 to 3000. Several laboratory tasks were completed in order to achieve the desired resolution. These included (1) development of techniques to align grid collimators, (2) studies of the spectrometric properties of crystals, (3) measurements of the absorption coefficients of various materials used in X-ray spectrometers, (4) evaluation of the performance of multiaperture cameras, and (5) development of facilities.

  13. High-temperature solar central receivers

    NASA Astrophysics Data System (ADS)

    Skinrood, A. C.

    1981-07-01

    Designs and concepts for solar central receiver thermal power plants are reviewed. Concentrations of over 1,000 suns are now possible, and seven prototype plants, producing from 1-10 MWe, are close to completion, employing cavity and external receiver configurations. Heat transfer fluids are discussed, noting that the water/steam cycle is emerging as the dominant mode; liquid sodium is benefitting from extensive testing for nuclear power plants; molten salt provides thermal storage at $10-30/kWt-hr; high temperature gas systems (815 C) can be applied for gypsum board drying and NH3 production. Heliostats are all of a steel/glass configuration and require mass production to become economical. Thermal storage systems, applications for repowering in conjunction with conventional power plants, and cogeneration for electricity/process heat are examined, and power costs are projected to match those of coal if the central receiver construction costs can be halved.

  14. Energetic solar proton versus terrestrially trapped proton fluxes for the active years 1977 - 1983

    NASA Technical Reports Server (NTRS)

    King, J. H.; Stassinopoulos, E. G.

    1974-01-01

    Ratios of solar to trapped proton fluences were computed for circular-orbit, geocentric space missions to be flown during the active phase of the next solar cycle (1977-1983). The ratios are presented as functions of orbit altitude and inclination, mission duration, proton energy threshold, and the chance the mission planner is willing to take that the actually encountered solar proton fluence will exceed the design fluence provided by the statistical solar proton model. It is shown that the ratio is most sensitively dependent on orbit altitude and inclination, with trapped protons dominant for low inclination, low and mid altitude orbits and for high inclination, mid altitude orbits. Conversely, solar protons are dominant for high inclination, low altitude orbits, and for low and high inclination, high altitude orbits.

  15. Solar flare acceleration of solar wind - Influence of active region magnetic field

    NASA Technical Reports Server (NTRS)

    Lundstedt, H.; Wilcox, J. M.; Scherrer, P. H.

    1981-01-01

    The direction of the photospheric magnetic field at the site of a solar flare is a good predictor of whether the flare will accelerate solar wind plasma. If the field has a southward component, high-speed solar wind plasma is usually observed near the earth about 4 days later. If the field has a northward component, such high-speed solar wind is almost never observed. Southward-field flares may then be expected to have much larger terrestrial effects than northward flares.

  16. Solar activity at birth predicted infant survival and women's fertility in historical Norway

    PubMed Central

    Skjærvø, Gine Roll; Fossøy, Frode; Røskaft, Eivin

    2015-01-01

    Ultraviolet radiation (UVR) can suppress essential molecular and cellular mechanisms during early development in living organisms and variations in solar activity during early development may thus influence their health and reproduction. Although the ultimate consequences of UVR on aquatic organisms in early life are well known, similar studies on terrestrial vertebrates, including humans, have remained limited. Using data on temporal variation in sunspot numbers and individual-based demographic data (N = 8662 births) from Norway between 1676 and 1878, while controlling for maternal effects, socioeconomic status, cohort and ecology, we show that solar activity (total solar irradiance) at birth decreased the probability of survival to adulthood for both men and women. On average, the lifespans of individuals born in a solar maximum period were 5.2 years shorter than those born in a solar minimum period. In addition, fertility and lifetime reproductive success (LRS) were reduced among low-status women born in years with high solar activity. The proximate explanation for the relationship between solar activity and infant mortality may be an effect of folate degradation during pregnancy caused by UVR. Our results suggest that solar activity at birth may have consequences for human lifetime performance both within and between generations. PMID:25567646

  17. Solar activity at birth predicted infant survival and women's fertility in historical Norway.

    PubMed

    Skjærvø, Gine Roll; Fossøy, Frode; Røskaft, Eivin

    2015-02-22

    Ultraviolet radiation (UVR) can suppress essential molecular and cellular mechanisms during early development in living organisms and variations in solar activity during early development may thus influence their health and reproduction. Although the ultimate consequences of UVR on aquatic organisms in early life are well known, similar studies on terrestrial vertebrates, including humans, have remained limited. Using data on temporal variation in sunspot numbers and individual-based demographic data (N = 8662 births) from Norway between 1676 and 1878, while controlling for maternal effects, socioeconomic status, cohort and ecology, we show that solar activity (total solar irradiance) at birth decreased the probability of survival to adulthood for both men and women. On average, the lifespans of individuals born in a solar maximum period were 5.2 years shorter than those born in a solar minimum period. In addition, fertility and lifetime reproductive success (LRS) were reduced among low-status women born in years with high solar activity. The proximate explanation for the relationship between solar activity and infant mortality may be an effect of folate degradation during pregnancy caused by UVR. Our results suggest that solar activity at birth may have consequences for human lifetime performance both within and between generations. PMID:25567646

  18. a Study of High Efficiency Thin Thermophotovoltaic Solar Cells.

    NASA Astrophysics Data System (ADS)

    Vera, Eduardo Sobrino

    1982-05-01

    High conversion efficiency of solar energy into electrical energy is possible if the incident radiation is first absorbed by an intermediate absorber and then re-emitted onto a photovoltaic (PV) solar cell. This mode of operation is known as solar thermophotovoltaic (TPV) energy conversion. This thesis explores the limits on performance of TPV systems based on germanium in which the source temperature and the opto-electronic structure of the germanium PV cell are varied and optimized with respect to overall radiant energy conversion efficiency. The principal characteristic of the optimized high efficiency TPV germanium cells is that they are thin p-n junction solar cells which incorporate minority carrier mirrors (MCM) and optical mirrors (OM) at the front and back surfaces of the device examined. In this study, the role of MCM and OM is studied theoretically by solving the minority carrier diffusion equation in the n- and p-type quasineutral regions of the cell with the appropriate boundary conditions at the end of these regions and an appropriate minority carrier generation function. The high theoretical efficiency calculated for these thin structures derives from the simultaneous use of optical and electronic reflection. The calculations presented here determine the theoretical upper limit to TPV conversion efficiency and show the dependence of this limit on cell geometry, resistivity, surface recombination and input density. In addition, TPV systems based on more than one PV cell, each utilizing a different photovoltaically active semiconductor are also considered. A number of possible TPV systems are treated within this theoretical framework. When blackbody thermal radiation sources having temperatures in the range 1500-2000 C are considered, the upper limit efficiency is found to be about 22% for an optimum design germanium cell 90 microns thick and about 26% for a two-junction silicon-germanium tandem cell arrangement 50 and 90 microns thick, respectively

  19. Highly efficient light management for perovskite solar cells

    PubMed Central

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells. PMID:26733112

  20. Highly efficient light management for perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

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

    SciTech Connect

    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)

  2. Possible relationships between solar activity and atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Roosen, R. G.; Angione, R. J.

    1975-01-01

    The large body of data on solar variations and atmospheric constituents collected between 1902 and 1953 by the Astrophysical Observatory of the Smithsonian Institution (APO) was examined. Short-term variations in amounts of atmospheric aerosols and water vapor due to seasonal changes, volcanic activity, air pollution, and frontal activity are discussed. Preliminary evidence indicates that increased solar activity is at times associated with a decrease in attenuation due to airborne particulates.

  3. Possible relationships between solar activity and atmospheric constituents

    NASA Technical Reports Server (NTRS)

    Roosen, R. G.; Angione, R. J.

    1974-01-01

    The large body of data on solar variations and atmospheric constituents collected between 1902 and 1953 by the Astrophysical Observatory of the Smithsonian Institution (APO) is examined. Short term variations in amounts of atmospheric aerosols and water vapor due to seasonal changes, volcanic activity, air pollution, and frontal activity are discussed. Preliminary evidence indicates that increased solar activity is at times associated with a decrease in attenuation due to airborne particulates.

  4. Solar activity index for long-term ionospheric forecasts

    NASA Astrophysics Data System (ADS)

    Deminov, M. G.

    2016-01-01

    Based on the comparison of solar activity indices (annual average values of the relative number of sunspots Rz 12 and solar radio emission flux at a wavelength of 10.7 cm F 12) with the ionospheric index of solar activity IG 12 for 1954-2013, we have found that the index F 12 is a more accurate (than Rz 12) indicator of solar activity for the long-term forecast of foF2 (the critical frequency of the F2-layer). This advantage of the F 12 index becomes especially significant after 2000 if the specific features of extreme ultraviolet radiation of the Sun are additionally taken into account in the minima of solar cycles, using an appropriate correction to F 12. Qualitative arguments are given in favor of the use of F 12 for the long-term forecast of both foF2 and other ionospheric parameters.

  5. 9,400 years of cosmic radiation and solar activity from ice cores and tree rings

    PubMed Central

    Steinhilber, Friedhelm; Beer, Jürg; Brunner, Irene; Christl, Marcus; Fischer, Hubertus; Heikkilä, Ulla; Kubik, Peter W.; Mann, Mathias; McCracken, Ken G.; Miller, Heinrich; Miyahara, Hiroko; Oerter, Hans

    2012-01-01

    Understanding the temporal variation of cosmic radiation and solar activity during the Holocene is essential for studies of the solar-terrestrial relationship. Cosmic-ray produced radionuclides, such as 10Be and 14C which are stored in polar ice cores and tree rings, offer the unique opportunity to reconstruct the history of cosmic radiation and solar activity over many millennia. Although records from different archives basically agree, they also show some deviations during certain periods. So far most reconstructions were based on only one single radionuclide record, which makes detection and correction of these deviations impossible. Here we combine different 10Be ice core records from Greenland and Antarctica with the global 14C tree ring record using principal component analysis. This approach is only possible due to a new high-resolution 10Be record from Dronning Maud Land obtained within the European Project for Ice Coring in Antarctica in Antarctica. The new cosmic radiation record enables us to derive total solar irradiance, which is then used as a proxy of solar activity to identify the solar imprint in an Asian climate record. Though generally the agreement between solar forcing and Asian climate is good, there are also periods without any coherence, pointing to other forcings like volcanoes and greenhouse gases and their corresponding feedbacks. The newly derived records have the potential to improve our understanding of the solar dynamics and to quantify the solar influence on climate. PMID:22474348

  6. SOLAR POWERING OF HIGH EFFICIENCY ABSORPTION CHILLER

    SciTech Connect

    Randy C. Gee

    2004-11-15

    This is the Final Report for two solar cooling projects under this Cooperative Agreement. The first solar cooling project is a roof-integrated solar cooling and heating system, called the Power Roof{trademark}, which began operation in Raleigh, North Carolina in late July 2002. This system provides 176 kW (50 ton) of solar-driven space cooling using a unique nonimaging concentrating solar collector. The measured performance of the system during its first months of operation is reported here, along with a description of the design and operation of this system. The second solar cooling system, with a 20-ton capacity, is being retrofit to a commercial office building in Charleston, South Carolina but has not yet been completed.

  7. Lyman-alpha line as a solar activity index for calculations of solar spectrum in the EUV region

    NASA Astrophysics Data System (ADS)

    Nusinov, Anatoliy; Kazachevskaya, Tamara; Katyushina, Valeria; Woods, Thomas

    It is investigated a possibility of retrieval of solar spectrum data using intensity observational data of the only solar spectral line L (Hydrogen Lyman-alpha, 121.6 nm).Using as an example spectra obtained by SEE instruments on TIMED satellite, it was shown, that both for lines and for continuum in the spectral range 27-105 nm, which is essential for ionization processes in the ionosphere, a correlation between their intensities and L was high. Therefore it becomes possible to use L measurements data as a natural solar activity index for calculations of EUV solar emission spectrum for solving aeronomical problems. It is noticed, that EUV model, obtained with using SEE data, does not allow to calculate correctly critical frequencies of ionospheric E-layer owing to low intensities of lines 97.7 and 102.6 nm, which produce the main part of ionization in ionospheric E-region.

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

    NASA Technical Reports Server (NTRS)

    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.

  9. Solar-collector manufacturing activity, July through December, 1981

    SciTech Connect

    1982-03-01

    Solar thermal collector and solar cell manufacturing activity is both summarized and tabulated. Data are compared for three survey periods (July through December, 1981; January through June, 1981; and July through December, 1980). Annual totals are also provided for the years 1979 through 1981. Data include total producer shipments, end use, market sector, imports and exports. (LEW)

  10. Solar Energy Education. Renewable energy activities for biology

    SciTech Connect

    Not Available

    1982-01-01

    An instructional aid for teachers is presented that will allow biology students the opportunity to learn about renewable energy sources. Some of the school activities include using leaves as collectors of solar energy, solar energy stored in wood, and a fuel value test for green and dry woods. A study of organic wastes as a source of fuel is included. (BCS)

  11. Solar energy education. Renewable energy activities for general science

    SciTech Connect

    Not Available

    1985-01-01

    Renewable energy topics are integrated with the study of general science. The literature is provided in the form of a teaching manual and includes such topics as passive solar homes, siting a home for solar energy, and wind power for the home. Other energy topics are explored through library research activities. (BCS)

  12. On the statistical relationship between solar activity and spontaneous social processes

    NASA Astrophysics Data System (ADS)

    Rodkin, M. V.; Kharin, E. P.

    2014-12-01

    The starting times of mass spontaneous social movements have been compared with temporal changes in solar activity (Wolf numbers) and in the Aa index of geomagnetic activity. It is shown that relatively high values of solar and, hence, geomagnetic activity are typical (on average) of a set of years when social cataclysms began. In addition, the relationship between social activity and geomagnetic activity is expressed somewhat more strongly than with solar activity. Heliogeomagnetic activity itself is not, however, the cause of social conflicts, as is evidenced by the weakness of the statistical relationship and the fact that the time intervals of an extremely large number of social conflicts (the decades of the 1800s, 1910s, and 1990s) occur during periods of a reduced mean level of solar and geomagnetic activity. From an averaged statistical model of the solar-geomagnetic influence on social activity and the current status and forecast of the 24th solar cycle, we can assume that heliogeomagnetic factors will contribute to an increased level of sociopolitical activity at least until the end of 2014 and, possibly, a little longer.

  13. Martian induced magnetosphere variations with solar activity cycle

    NASA Astrophysics Data System (ADS)

    Fedorov, Andrey; Ronan, Modolo; Jarninen, Riku; Mazelle, Christian; Barabash, Stas

    2014-05-01

    During the last 6 years of ESA Mars Express mission we have accumulated plasma data taken inside and around the Martian induced magnetosphere corresponding to the increasing branch of solar activity. This data allows to make an enhanced study of the magnetosphere variations as a response of the solar activity level. Since Mars Express has no onboard magnetometer, we used the hybrid models of the Martian plasma environment to get a proper frame to make an adequate statistics of the magnetospheric response. In this paper we present a spatial distribution of the planetary plasma in the planetary wake as well as the ionsospheric escape as a function of the solar activity.

  14. Influenza pandemics, solar activity cycles, and vitamin D.

    PubMed

    Hayes, Daniel P

    2010-05-01

    There is historic evidence that influenza pandemics are associated with solar activity cycles (the Schwabe-cycle of about 11-years periodicity). The hypothesis is presented and developed that influenza pandemics are associated with solar control of vitamin D levels in humans which waxes and wanes in concert with solar cycle dependent ultraviolet radiation. It is proposed that this solar cycle dependence arises both directly from cyclic control of the amount of ultraviolet radiation as well as indirectly through cyclic control of atmospheric circulation and dynamics. PMID:20056531

  15. A Solar Cycle Dependence of Nonlinearity in Magnetospheric Activity

    SciTech Connect

    Johnson, Jay R; Wing, Simon

    2005-03-08

    The nonlinear dependencies inherent to the historical K(sub)p data stream (1932-2003) are examined using mutual information and cumulant based cost as discriminating statistics. The discriminating statistics are compared with surrogate data streams that are constructed using the corrected amplitude adjustment Fourier transform (CAAFT) method and capture the linear properties of the original K(sub)p data. Differences are regularly seen in the discriminating statistics a few years prior to solar minima, while no differences are apparent at the time of solar maximum. These results suggest that the dynamics of the magnetosphere tend to be more linear at solar maximum than at solar minimum. The strong nonlinear dependencies tend to peak on a timescale around 40-50 hours and are statistically significant up to one week. Because the solar wind driver variables, VB(sub)s and dynamical pressure exhibit a much shorter decorrelation time for nonlinearities, the results seem to indicate that the nonlinearity is related to internal magnetospheric dynamics. Moreover, the timescales for the nonlinearity seem to be on the same order as that for storm/ring current relaxation. We suggest that the strong solar wind driving that occurs around solar maximum dominates the magnetospheric dynamics suppressing the internal magnetospheric nonlinearity. On the other hand, in the descending phase of the solar cycle just prior to solar minimum, when magnetospheric activity is weaker, the dynamics exhibit a significant nonlinear internal magnetospheric response that may be related to increased solar wind speed.

  16. Grand minima of solar activity and sociodynamics of culture

    NASA Astrophysics Data System (ADS)

    Vladimirsky, B. M.

    2012-12-01

    Indices of creative productivity introduced by C. Murrey were used to verify S. Ertel's conclusion about a global increase in creative productivity during the prolonged minimum of solar activity in 1640-1710. It was found that these indices for mathematicians, philosophers, and scientists increase in the Maunder era by factor of 1.6 in comparison with intervals of the same length before and after the minimum. A similar effect was obtained for mathematicians and philosophers for five earlier equitype minima in total (an increase by a factor of 1.9). The regularity that is revealed is confirmed by the fact that the most important achievements of high-ranking mathematicians and philosophers during the whole time period (2300 years) considered in this study fall on epochs of reduced levels of solar activity. The rise in the probability of the generation of rational ideas during grand minima is reflected also in the fact that they precede the appearance of written language and farming. Ultra-low-frequency electromagnetic fields appear to serve as a physical agent stimulating the activity of the brain's left hemisphere during the epochs of minima.

  17. The effect of solar activity on the evolution of solar wind parameters during the rise of the 24th cycle

    NASA Astrophysics Data System (ADS)

    Rod'kin, D. G.; Shugay, Yu. S.; Slemzin, V. A.; Veselovskii, I. S.

    2016-01-01

    The dynamics of parameters of the near-Earth solar wind (SW) and the effect of solar activity on the parameters of three SW components (fast SW from large-scale coronal holes (CHs); slow SW from active regions, streamers, and other sources; and transient flows related to sporadic solar activity) at the beginning of the 24th solar cycle (2009-2011) are analyzed. It is demonstrated that temperaturedependent parameters of ionic composition (C+6/C+5 and O+7/O+6) of the transient SW component in the profound minimum of solar activity in 2009 were correlated with the variation of the rate of weak (type C and weaker) flares. This verifies the presence of a hot component associated with these flares in the SW. The variations in the velocity and the kinetic temperature of fast SW from CHs with an increase in activity are more pronounced in the bulk of the high-speed stream, and the variations of O+7/O+6 and Fe/O ratios and the magnitude of the interplanetary magnetic field are the most prominent in the region of interaction between fast and slow SW streams. The analysis reveals that a value of O+7/O+6 = 0.1 serves as the criterion to distinguish between fast SW streams and interplanetary coronal mass ejections in the 2009 activity minimum. This value is lower than the one (0.145) determined earlier based on the data on the 23rd cycle (Zhao et al., 2009). Therefore, the distinguishing criterion is not an absolute one and depends on the solar activity level.

  18. Solar Power for Near Sun, High-Temperature Missions

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2008-01-01

    Existing solar cells lose performance at the high temperatures encountered in Mercury orbit and inward toward the sun. For future missions designed to probe environments close to the sun, it is desirable to develop array technologies for high temperature and high light intensity. Approaches to solar array design for near-sun missions include modifying the terms governing temperature of the cell and the efficiency at elevated temperature, or use of techniques to reduce the incident solar energy to limit operating temperature. An additional problem is found in missions that involve a range of intensities, such as the Solar Probe + mission, which ranges from a starting distance of 1 AU from the sun to a minimum distance of 9.5 solar radii, or 0.044 AU. During the mission, the solar intensity ranges from one to about 500 times AM0. This requires a power system to operate over nearly three orders of magnitude of incident intensity.

  19. Variation of D-region nitric-oxide density with solar activity and season at the dip equator

    NASA Technical Reports Server (NTRS)

    Chakrabarty, D. K.; Pakhomov, S. V.; Beig, G.

    1989-01-01

    To study the solar control on electron density (N sub e) in the equatorial D region, a program was initiated with Soviet collaboration in 1979. A total of 31 rockets were launched during the high solar activity period, and 47 rockets during the low solar activity period, from Thumba to measure the N sub e profiles. Analysis of the data shows that the average values of N sub e for the high solar activity period are higher by a factor of about 2 to 3 compared to the low solar activity values. It was found that a single nitric oxide density, (NO), profile cannot reproduce all the observed N sub e profiles. An attempt was made to reproduce theoretically the observed N sub e profiles by introducing variation in (NO) for the different solar activity periods and seasons.

  20. The dynamic solar chromosphere: recent advances from high resolution telescopes

    NASA Astrophysics Data System (ADS)

    Tziotziou, Konstantinos; Tsiropoula, Georgia

    This review focuses on the solar chromosphere, a very inhomogeneous and dynamic layer that exhibits phenomena on a large range of spatial and temporal scales. High-resolution observa-tions from existing telescopes (DST, SST, DOT), as well as long-duration observations with Hinode's SOT employing lines such as the Ca II infrared lines, the Ca II HK and above all the Hα line reveal an incredibly rich, dynamic and highly structured environment, both in quiet and active regions. The fine-structure chromosphere, is mainly constituted by fibrilar features that connect various parts of active regions or span across network cell interiors. We discuss this highly dynamical solar chromosphere, especially below the magnetic canopy, which is gov-erned by flows reflecting both the complex geometry and dynamics of the magnetic field and the propagation and dissipation of waves in the different atmospheric layers. A comprehensive view of the fine-structure chromosphere requires deep understanding of the physical processes involved, investigation of the intricate link with structures/processes at lower photospheric lev-els and analysis of its impact on the mass and energy transport to higher atmospheric layers through flows resulting from different physical processes such as magnetic reconnection and waves. Furthermore, we assess the challenges facing theory and numerical modelling which require the inclusion of several physical ingredients, such as non-LTE and three-dimensional numerical simulations.

  1. Preliminary design activities for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Information on the development of solar heating and cooling systems is presented. 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.

  2. Solar activity around AD 775 from aurorae and radiocarbon

    NASA Astrophysics Data System (ADS)

    Neuhäuser, R.; Neuhäuser, D. L.

    2015-04-01

    A large variation in 14C around AD 775 has been considered to be caused by one or more solar super-flares within one year. We critically review all known aurora reports from Europe as well as the Near, Middle, and Far East from AD 731 to 825 and find 39 likely true aurorae plus four more potential aurorae and 24 other reports about halos, meteors, thunderstorms etc., which were previously misinterpreted as aurorae or misdated; we assign probabilities for all events according to five aurora criteria. We find very likely true aurorae in AD 743, 745, 762, 765, 772, 773, 793, 796, 807, and 817. There were two aurorae in the early 770s observed near Amida (now Diyarbak\\i r in Turkey near the Turkish-Syrian border), which were not only red, but also green-yellow - being at a relatively low geomagnetic latitude, they indicate a relatively strong solar storm. However, it cannot be argued that those aurorae (geomagnetic latitude 43 to 50°, considering five different reconstructions of the geomagnetic pole) could be connected to one or more solar super-flares causing the 14C increase around AD 775: There are several reports about low- to mid-latitude aurorae at 32 to 44° geomagnetic latitude in China and Iraq; some of them were likely observed (quasi-)simultaneously in two of three areas (Europe, Byzantium/Arabia, East Asia), one lasted several nights, and some indicate a particularly strong geomagnetic storm (red colour and dynamics), namely in AD 745, 762, 793, 807, and 817 - always without 14C peaks. We use 39 likely true aurorae as well as historic reports about sunspots together with the radiocarbon content from tree rings to reconstruct the solar activity: From AD {˜ 733} to {˜ 823}, we see at least nine Schwabe cycles; instead of one of those cycles, there could be two short, weak cycles - reflecting the rapid increase to a high 14C level since AD 775, which lies at the end of a strong cycle. In order to show the end of the dearth of naked-eye sunspots, we

  3. Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation

    PubMed Central

    Yu, Shuyan; Liu, Jincheng; Zhu, Wenyu; Hu, Zhong-Ting; Lim, Teik-Thye; Yan, Xiaoli

    2015-01-01

    Carboxylic acid functionalized graphene oxide-copper (II) sulfide nanoparticle composite (GO-COOH-CuS) was prepared from carboxylated graphene oxide and copper precursor in dimethyl sulfoxide (DMSO) by a facile synthesis process at room temperature. The high-effective combination, the interaction between GO-COOH sheets and CuS nanoparticles, and the enhanced visible light absorption were confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra. The as-synthesized GO-COOH-CuS nanocomposite exhibited excellent photocatalytic degradation performance of phenol and rhodamine B, high antibacterial activity toward E. coli and B. subtilis, and good recovery and reusability. The influence of CuS content, the synergistic reaction between CuS and GO-COOH, and the charge-transfer mechanism were systematically investigated. The facile and low-energy synthesis process combined with the excellent degradation and antibacterial performance signify that the GO-COOH-CuS has a great potential for water treatment application. PMID:26553709

  4. Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation.

    PubMed

    Yu, Shuyan; Liu, Jincheng; Zhu, Wenyu; Hu, Zhong-Ting; Lim, Teik-Thye; Yan, Xiaoli

    2015-01-01

    Carboxylic acid functionalized graphene oxide-copper (II) sulfide nanoparticle composite (GO-COOH-CuS) was prepared from carboxylated graphene oxide and copper precursor in dimethyl sulfoxide (DMSO) by a facile synthesis process at room temperature. The high-effective combination, the interaction between GO-COOH sheets and CuS nanoparticles, and the enhanced visible light absorption were confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra. The as-synthesized GO-COOH-CuS nanocomposite exhibited excellent photocatalytic degradation performance of phenol and rhodamine B, high antibacterial activity toward E. coli and B. subtilis, and good recovery and reusability. The influence of CuS content, the synergistic reaction between CuS and GO-COOH, and the charge-transfer mechanism were systematically investigated. The facile and low-energy synthesis process combined with the excellent degradation and antibacterial performance signify that the GO-COOH-CuS has a great potential for water treatment application. PMID:26553709

  5. Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation

    NASA Astrophysics Data System (ADS)

    Yu, Shuyan; Liu, Jincheng; Zhu, Wenyu; Hu, Zhong-Ting; Lim, Teik-Thye; Yan, Xiaoli

    2015-11-01

    Carboxylic acid functionalized graphene oxide-copper (II) sulfide nanoparticle composite (GO-COOH-CuS) was prepared from carboxylated graphene oxide and copper precursor in dimethyl sulfoxide (DMSO) by a facile synthesis process at room temperature. The high-effective combination, the interaction between GO-COOH sheets and CuS nanoparticles, and the enhanced visible light absorption were confirmed by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and Photoluminescence (PL) spectra. The as-synthesized GO-COOH-CuS nanocomposite exhibited excellent photocatalytic degradation performance of phenol and rhodamine B, high antibacterial activity toward E. coli and B. subtilis, and good recovery and reusability. The influence of CuS content, the synergistic reaction between CuS and GO-COOH, and the charge-transfer mechanism were systematically investigated. The facile and low-energy synthesis process combined with the excellent degradation and antibacterial performance signify that the GO-COOH-CuS has a great potential for water treatment application.

  6. Detrimental Effects of Extreme Solar Activity on Life on Earth

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Glocer, Alex; Jackman, Charles

    2015-07-01

    Solar Coronal Mass Ejections (CMEs), the most energetic eruptions in the Solar System, represent large-scale disturbances forming with the solar corona and are associated with solar flares and Solar Energetic Particles (SEP) events. Current Kepler data from solar-like stars suggest that the frequency of occurrence of energetic flares and associated CMEs from the Sun can be as high as 1 per 1500 years. What effects would CME and associated SEPs have on Earth's habitability? We have performed a three-dimensional time-dependent global magnetohydrodynamic simulation of the magnetic interaction of such a CME cloud with the Earth's magnetosphere. We calculated the global structure of the perturbed magnetosphere and derive the latitude of the open-closed magnetic field boundary. We used a 2D GSFC atmospheric code to calculate the efficiency of ozone depletion in the Earth's atmosphere due to SEP events and its effects on our society and life on Earth.

  7. Detectability of active triangulation range finder: a solar irradiance approach.

    PubMed

    Liu, Huizhe; Gao, Jason; Bui, Viet Phuong; Liu, Zhengtong; Lee, Kenneth Eng Kian; Peh, Li-Shiuan; Png, Ching Eng

    2016-06-27

    Active triangulation range finders are widely used in a variety of applications such as robotics and assistive technologies. The power of the laser source should be carefully selected in order to satisfy detectability and still remain eye-safe. In this paper, we present a systematic approach to assess the detectability of an active triangulation range finder in an outdoor environment. For the first time, we accurately quantify the background noise of a laser system due to solar irradiance by coupling the Perez all-weather sky model and ray tracing techniques. The model is validated with measurements with a modeling error of less than 14.0%. Being highly generic and sufficiently flexible, the proposed model serves as a guide to define a laser system for any geographical location and microclimate. PMID:27410637

  8. High mortality of Red Sea zooplankton under ambient solar radiation.

    PubMed

    Al-Aidaroos, Ali M; El-Sherbiny, Mohsen M O; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h(-1), five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM) 12±5.6 h(-1)% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean. PMID:25309996

  9. Effects of Low Activity Solar Cycle on Orbital Debris Lifetime

    NASA Technical Reports Server (NTRS)

    Cable, Samual B.; Sutton, Eric K.; Lin, chin S.; Liou, J.-C.

    2011-01-01

    Long duration of low solar activity in the last solar minimum has an undesirable consequence of extending the lifetime of orbital debris. The AFRL TacSat-2 satellite decommissioned in 2008 has finally re-entered into the atmosphere on February 5th after more than one year overdue. Concerning its demise we have monitored its orbital decay and monthly forecasted Tacsat-2 re-entry since September 2010 by using the Orbital Element Prediction (OEP) model developed by the AFRL Orbital Drag Environment program. The model combines estimates of future solar activity with neutral density models, drag coefficient models, and an orbit propagator to predict satellite lifetime. We run the OEP model with solar indices forecast by the NASA Marshall Solar Activity Future Estimation model, and neutral density forecast by the MSIS-00 neutral density model. Based on the two line elements in 2010 up to mid September, we estimated at a 50% confidence level TacSat-2's re-entry time to be in early February 2011, which turned out to be in good agreement with Tacsat-2's actual re-entry date. The potential space weather effects of the coming low activity solar cycle on satellite lifetime and orbital debris population are examined. The NASA long-term orbital debris evolutionary model, LEGEND, is used to quantify the effects of solar flux on the orbital debris population in the 200-600 km altitude environment. The results are discussed for developing satellite orbital drag application product.

  10. Solar activity dependence of nightside aurora in winter conditions

    NASA Astrophysics Data System (ADS)

    Zhou, Su; Luan, Xiaoli; Dou, Xiankang

    2016-02-01

    The dependence of the nightside (21:00-03:00 MLT; magnetic local time) auroral energy flux on solar activity was quantitatively studied for winter/dark and geomagnetically quiet conditions. Using data combined from Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Global Ultraviolet Imager and Defense Meteorological Satellite Program/Special Sensor Ultraviolet Spectrographic Imager observations, we separated the effects of geomagnetic activity from those of solar flux on the nightside auroral precipitation. The results showed that the nightside auroral power was reduced by ~42% in solar maximum (F10.7 = 200 sfu; solar flux unit 1 sfu = 10-22 W m-2 Hz-1) with respect to that under solar minimum (F10.7 = 70 sfu) for the Kp = 1 condition, and this change rate became less (~21%) for the Kp = 3 condition. In addition, the solar cycle dependence of nightside auroral power was similar with that from both the premidnight (21:00-23:00 MLT) and postmidnight (01:00-03:00 MLT) sectors. These results indicated that as the ionospheric ionization increases with the enhanced auroral and geomagnetic activities, the solar activity dependences of nightside auroral power become weaker, at least under geomagnetically quiet conditions.

  11. The Solar Non-activity Cycle of Polar Coronal Holes

    NASA Astrophysics Data System (ADS)

    Kirk, M. S.; Pesnell, W. D.; Young, C. A.

    2015-12-01

    After the unusually extended minimum in 2008 and 2009, solar cycle 24 continues to be an exceptionally weak cycle both in sunspot number and number of large magnetic storms. Coronal holes offer a direct measurement of the non-activity solar cycle, a missing link in our understanding of solar cycle progression. They are prevalent during solar minimum, non-axisymmetric, and are stable. Polar coronal holes are regularly observed capping the northern and southern solar poles in EUV images of the corona and are understood as the primary source of the fast solar wind. We make measurements of these features from 1996 through 2015 using four different NASA imagers: SOHO EIT, STEREO A and B EUVI, and SDO AIA. A measurement of the axial symmetry of the polar holes is seen to have clear solar cycle dependence. Polar coronal holes are aligned with the solar rotation axis during minimum and have a maximum asymmetry between holes of about 14 degrees in the declining phase of the current solar cycle.

  12. DSCOVR High Time Resolution Solar Wind Measurements

    NASA Technical Reports Server (NTRS)

    Szabo, Adam

    2012-01-01

    The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.

  13. Planar multijunction high voltage solar cell chip

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Kapoor, V. J.; Evans, J. C., Jr.

    1982-01-01

    A new innovative planar multijunction solar cell chip for concentrated sunlight applications is proposed. The chip consists of many voltage-generating regions, called unit cells, which are connected in series within a single silicon wafer, thereby providing a high open-circuit voltage at multiple sun illumination levels. The unit cells are fabricated on 75 micron thick p-type single crystal silicon substrate. Each chip consists of 1.42 x 9.63 mm n(+)/p collecting junctions on the back of the wafer, while the illuminated front surface area is divided into 0.3 micron deep n(+) regions. The fabrication sequence includes standard degreasing and cleaning procedures, double-sided alignment photomasking, introduction of boron and phosphorus impurities, and photolithography. The open circuit voltage of the chip increased rapidly with illumination up to about 4 AM1 suns, and then began to saturate at the sum of the individual unit cell voltages of 3.5 above 4 AM1 suns. A short circuit density per unit cell of 300 mA/sq cm at 20 AM1 suns was observed.

  14. High Lifetime Solar Cell Processing and Design

    NASA Technical Reports Server (NTRS)

    Swanson, R. M.

    1985-01-01

    In order to maximize efficiency a solar cell must: (1) absorb as much light as possible in electron-hole production, (2) transport as large a fraction as possible of the electrons to the n-type terminal and holes to the p-type terminal without their first recombining, and (3) produce as high as possible terminal voltage. Step (1) is largely fixed by the spectrum of sunlight and the fundamental absorption characteristics of silicon, although some improvements are possible through texturizing induced light trapping and back surface reflectors. Steps (2) and (3) are, however, dependent on the recombination mechanisms of the cell. The recombination, on the contrary, is strongly influenced by cell processing and design. Some of the lessons during the development of point-contact-cell are discussed. Cell dependence on recombination, surface recombination, and contact recombination are discussed. Results show the overwhelming influence of contact recombination on the operation of the cell when the other sources of recombination are reduced by careful processing.

  15. Radio Imaging Observations of Solar Activity Cycle and Its Anomaly

    NASA Astrophysics Data System (ADS)

    Shibasaki, K.

    2011-12-01

    The 24th solar activity cycle has started and relative sunspot numbers are increasing. However, their rate of increase is rather slow compared to previous cycles. Active region sizes are small, lifetime is short, and big (X-class) flares are rare so far. We study this anomalous situation using data from Nobeyama Radioheliograph (NoRH). Radio imaging observations have been done by NoRH since 1992. Nearly 20 years of daily radio images of the Sun at 17 GHz are used to synthesize a radio butterfly diagram. Due to stable operation of the instrument and a robust calibration method, uniform datasets are available covering the whole period of observation. The radio butterfly diagram shows bright features corresponding to active region belts and their migration toward low latitude as the solar cycle progresses. In the present solar activity cycle (24), increase of radio brightness is delayed and slow. There are also bright features around both poles (polar brightening). Their brightness show solar cycle dependence but peaks around solar minimum. Comparison between the last minimum and the previous one shows decrease of its brightness. This corresponds to weakening of polar magnetic field activity between them. In the northern pole, polar brightening is already weakened in 2011, which means it is close to solar maximum in the northern hemisphere. Southern pole does not show such feature yet. Slow rise of activity in active region belt, weakening of polar activity during the minimum, and large north-south asymmetry in polar activity imply that global solar activity and its synchronization are weakening.

  16. High heat flux engineering in solar energy applications

    SciTech Connect

    Cameron, C.P.

    1993-07-01

    Solar thermal energy systems can produce heat fluxes in excess of 10,000 kW/m{sup 2}. This paper provides an introduction to the solar concentrators that produce high heat flux, the receivers that convert the flux into usable thermal energy, and the instrumentation systems used to measure flux in the solar environment. References are incorporated to direct the reader to detailed technical information.

  17. Helicity from observational solar magnetic fields and the relationship with solar activities

    NASA Astrophysics Data System (ADS)

    Zhang, Hongqi

    The helicity is important to present the basic topological configuration of magnetic field trans-ferred form the solar subatmosphere into the interplanetary space. In this talk, the basic configuration of magnetic field and helicity in the solar atmosphere have been discussed in the following: 1) The Hinode high resolution vector magnetograms provide the important infor-mation on the fine features of current helicity density and the possible accumulated process of magnetic helicity in the solar atmosphere. 2) The relationship between the eruption of solar flare-CMEs and helicity transfer from the suntamosphere has be presented based on the analy-sis of photospheric vector magnetograms. 3) The statistical distribution of magnetic field (and helicity) in solar atmosphere and its reversals with solar cycles are presented by means of the observational (vector) magnetograms. As the magnetic fields in the solar surface provides the information on the formation of magnetic field in the solar convection zone, the statistical anal-ysis of the observational magnetic helicity is important for the confirmation of the alpha-effect of the solar dynamo.

  18. Processing on high efficiency solar collector coatings

    NASA Technical Reports Server (NTRS)

    Roberts, M.

    1977-01-01

    Wavelength selective coatings for solar collectors are considered. Substrates with good infrared reflectivity were examined along with their susceptibility to physical and environmental damage. Improvements of reflective surfaces were accomplished through buffing, chemical polishing and other surface processing methods.

  19. Photoconductive Cathode Interlayer for Highly Efficient Inverted Polymer Solar Cells.

    PubMed

    Nian, Li; Zhang, Wenqiang; Zhu, Na; Liu, Linlin; Xie, Zengqi; Wu, Hongbin; Würthner, Frank; Ma, Yuguang

    2015-06-10

    A highly photoconductive cathode interlayer was achieved by doping a 1 wt % light absorber, such as perylene bisimide, into a ZnO thin film, which absorbs a very small amount of light but shows highly increased conductivity of 4.50 × 10(-3) S/m under sunlight. Photovoltaic devices based on this kind of photoactive cathode interlayer exhibit significantly improved device performance, which is rather insensitive to the thickness of the cathode interlayer over a broad range. Moreover, a power conversion efficiency as high as 10.5% was obtained by incorporation of our photoconductive cathode interlayer with the PTB7-Th:PC71BM active layer, which is one of the best results for single-junction polymer solar cells. PMID:26016386

  20. Level and length of cyclic solar activity during the Maunder minimum as deduced from the active-day statistics

    NASA Astrophysics Data System (ADS)

    Vaquero, J. M.; Kovaltsov, G. A.; Usoskin, I. G.; Carrasco, V. M. S.; Gallego, M. C.

    2015-05-01

    Aims: The Maunder minimum (MM) of greatly reduced solar activity took place in 1645-1715, but the exact level of sunspot activity is uncertain because it is based, to a large extent, on historical generic statements of the absence of spots on the Sun. Using a conservative approach, we aim to assess the level and length of solar cycle during the MM on the basis of direct historical records by astronomers of that time. Methods: A database of the active and inactive days (days with and without recorded sunspots on the solar disc) is constructed for three models of different levels of conservatism (loose, optimum, and strict models) regarding generic no-spot records. We used the active day fraction to estimate the group sunspot number during the MM. Results: A clear cyclic variability is found throughout the MM with peaks at around 1655-1657, 1675, 1684, 1705, and possibly 1666, with the active-day fraction not exceeding 0.2, 0.3, or 0.4 during the core MM, for the three models. Estimated sunspot numbers are found to be very low in accordance with a grand minimum of solar activity. Conclusions: For the core MM (1650-1700), we have found that (1) A large portion of no-spot records, which correspond to the solar meridian observations, may be unreliable in the conventional database. (2) The active-day fraction remained low (below 0.3-0.4) throughout the MM, indicating the low level of sunspot activity. (3) The solar cycle appears clearly during the core MM. (4) The length of the solar cycle during the core MM appears for 9 ± 1 years, but this is uncertain. (5) The magnitude of the sunspot cycle during MM is assessed to be below 5-10 in sunspot numbers. A hypothesis of the high solar cycles during the MM is not confirmed.

  1. Active-solar-energy-system materials research priorities

    SciTech Connect

    Herzenberg, S.A.; Hien, L.K.; Silberglitt, R.

    1983-01-01

    THis report describes and prioritizes materials research alternatives to improve active solar heating and cooling system cost-effectiveness. Materials research areas analyzed are (polymer) glazings, heat mirrors, (selective) absorber surfaces, absorber adhesives, absorber substrates, fluids, thermal storage materials, and desiccants. Three classes of solar collectors are considered in the cost-effectiveness analysis: medium-temperature flat-plate collectors (operating temperature, 70/sup 0/C); high-temperature flat-plate collectors (operating temperature, 70 to 120/sup 0/C); and evacuated tubes (operating temperature 70 to 230/sup 0/C). We found the highest priority for medium-temperature flat-plate collectors to be research on polymeric materials to improve performance and durability characteristics. For the high-temperature, flat-plate collectors and evacuated tubes, heat mirror and selective absorber research is the highest priority. Research on storage materials, fluids, and desiccants is of relatively low priority for improving cost-effectiveness in all cases. The highest priority materials research areas identified include: optical properties and degradation of transparent conducting oxide heat mirrors and thickness insensitive selective paints; uv and thermal stabilization of polymeric glazing materials; and systems analysis of integrated polymeric collectors.

  2. The risk characteristics of solar and geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Podolska, Katerina

    2016-04-01

    The main aim of this contribution is a deeper analysis of the influence of solar activity which is expected to have an impact on human health, and therefore on mortality, in particular civilization and degenerative diseases. We have constructed the characteristics that represent the risk of solar and geomagnetic activity on human health on the basis of our previous analysis of association between the daily numbers of death on diseases of the nervous system and diseases of the circulatory system and solar and geomagnetic activity in the Czech Republic during the years 1994 - 2013. We used long period daily time series of numbers of deaths by cause, long period time series of solar activity indices (namely R and F10.7), geomagnetic indicies (Kp planetary index, Dst) and ionospheric parameters (foF2 and TEC). The ionospheric parameters were related to the geographic location of the Czech Republic and adjusted for middle geographic latitudes. The risk characteristics were composed by cluster analysis in time series according to the phases of the solar cycle resp. the seasonal insolation at mid-latitudes or the daily period according to the impact of solar and geomagnetic activity on mortality by cause of death from medical cause groups of death VI. Diseases of the nervous system and IX. Diseases of the circulatory system mortality by 10th Revision of International Classification of Diseases WHO (ICD-10).

  3. Morphology of 557.7 nm dayglow emission under varying solar activity conditions

    NASA Astrophysics Data System (ADS)

    Krishna, M. V. Sunil; Singh, Vir

    The atomic oxygen emission at 557.7 nm is the most widely observed airglow feature in the upper mesosphere and lower thermospheric regions. The approximation of solar irradiance fluxes is very crucial in the modeling of this emission. The recently introduced Solar2000 EUV flux model is a suitable candidate to provide the solar EUV flux for any level of solar activity on any given day. The Solar2000 EUV flux model has not been tested for its applicability in the airglow modeling studies. In the present study a comprehensive model has been developed to study the 557.7 nm dayglow emission using Solar2000 EUV flux model. This study presents the model results of diurnal and yearly variations of 557.7 nm dayglow emission under equinox conditions. The effect of varying solar activity on this emission is studied for a period of five years (2001-2005) at a fixed date of April 3. This date is chosen due to the fact of large variations in the solar activity during the period of five years. The volume emission rates obtained from the model in the upper mesospheric region are found higher than the observed results. This discrepancy is due to the extremely high values of solar EUV flux generated by the Solar2000 EUV flux model at 102.5 and 103.7 nm wavelengths. The model is found in good agreement with the measurements in the thermospheric region. The morphology is presented as a function of F10.7 solar index for five years (2001 -2005) equator and 45° N at a fixed longitude.

  4. Observations of hysteresis in solar cycle variations among seven solar activity indicators

    NASA Technical Reports Server (NTRS)

    Bachmann, Kurt T.; White, Oran R.

    1994-01-01

    We show that smoothed time series of 7 indices of solar activity exhibit significant solar cycle dependent differences in their relative variations during the past 20 years. In some cases these observed hysteresis patterns start to repeat over more than one solar cycle, giving evidence that this is a normal feature of solar variability. Among the indices we study, we find that the hysteresis effects are approximately simple phase shifts, and we quantify these phase shifts in terms of lag times behind the leading index, the International Sunspot Number. Our measured lag times range from less than one month to greater than four months and can be much larger than lag times estimated from short-term variations of these same activity indices during the emergence and decay of major active regions. We argue that hysteresis represents a real delay in the onset and decline of solar activity and is an important clue in the search for physical processes responsible for changing solar emission at various wavelengths.

  5. Photodegradation effects in materials exposed to high flux solar and solar simulated radiation

    SciTech Connect

    Ignatiev, A.

    1992-04-01

    This report contains study results about photodegradation effects in materials exposed to high flux solar and solar simulated radiation. The studies show that high flux photoirradiation of materials can result in significant changes in the stability of materials. Photodesorption and photo-enhanced oxidation were determined to be the major mechanisms. These mechanisms were shown to affect, in extremely adverse ways, the expected thermal stability of solar relevant materials, especially stainless steels, (It is expected that related high temperature alloy steels will be similarly affected.) An analytical expression was generated to predict the flux behavior of the steels using {number_sign}304 as a prototypical stainless steel system.

  6. Photodegradation effects in materials exposed to high flux solar and solar simulated radiation

    SciTech Connect

    Ignatiev, A

    1992-04-01

    This report contains study results about photodegradation effects in materials exposed to high flux solar and solar simulated radiation. The studies show that high flux photoirradiation of materials can result in significant changes in the stability of materials. Photodesorption and photo-enhanced oxidation were determined to be the major mechanisms. These mechanisms were shown to affect, in extremely adverse ways, the expected thermal stability of solar relevant materials, especially stainless steels, (It is expected that related high temperature alloy steels will be similarly affected.) An analytical expression was generated to predict the flux behavior of the steels using {number sign}304 as a prototypical stainless steel system.

  7. Bringing Real Solar Physics to the High School Classroom

    NASA Astrophysics Data System (ADS)

    Seaton, Daniel

    2006-06-01

    UNH's Partnership for Research Opportunities to Benefit Education (PROBE) project sends graduate students into high school classrooms across New Hampshire in order to help introduce students to authentic scientific inquiry. As one of ten graduate fellows, I worked with students in in ninth through twelfth grades in physical science, physics, earth science, and astronomy classes; helping students carry out individual and class projects on physics and solar physics. Projects related to solar physics included the production and analysis of plasma using a microwave oven, measurement of the solar constant, measurement of the solar rotation rate, solar spectroscopy, analysis of data from TRACE and SOHO, and the construction of various solar-powered devices. This work was generously supported by a grant from the National Science Foundation's GK-12 initiative (NSF#0338277).

  8. High-energy particles associated with solar flares

    NASA Technical Reports Server (NTRS)

    Sakurai, K.; Klimas, A. J.

    1974-01-01

    High-energy particles, the so-called solar cosmic rays, are often generated in association with solar flares, and then emitted into interplanetary space. These particles, consisting of electrons, protons, and other heavier nuclei, including the iron-group, are accelerated in the vicinity of the flare. By studying the temporal and spatial varation of these particles near the earth's orbit, their storage and release mechanisms in the solar corona and their propagation mechanism can be understood. The details of the nuclear composition and the rigidity spectrum for each nuclear component of the solar cosmic rays are important for investigating the acceleration mechanism in solar flares. The timing and efficiency of the acceleration process can also be investigated by using this information. These problems are described in some detail by using observational results on solar cosmic rays and associated phenomena.

  9. HEUVAC: A new high resolution solar EUV proxy model

    NASA Astrophysics Data System (ADS)

    Richards, Philip G.; Woods, Thomas N.; Peterson, William K.

    This paper presents a new high-resolution version of the solar EUV irradiance model for aeronomic calculations (HEUVAC) that is designed to facilitate comparisons with measured spectra and enable more accurate calculations of ionization rates, airglow emission rates, and photoelectron calculations. The HEUVAC model bins can range from 0.1 to 100 nm and extends the EUV model below 5 nm. The new solar EUV irradiance calculations with the high resolution irradiance model show good agreement with the most recent solar EUV irradiance measurements from the solar EUV experiment (SEE) instrument on the thermosphere, ionosphere, mesosphere, energetics, and dynamics satellite. Also, photoelectron fluxes calculated from both the SEE measured and EUVAC modeled solar EUV irradiances agree well with photoelectron flux measurements by the FAST satellite. The good agreement of the EUVAC and SEE derived photoelectron fluxes with the FAST measured fluxes at solar maximum lends support to an earlier finding that the previous reference solar EUV irradiances from the Atmosphere Explorer measurements need to be adjusted upward by a factor of 2 3 below 25 nm wavelength. This result is important for remote sensing of the ionosphere and thermosphere because, as this paper shows, the airglow emission rates calculated using the SEE and HEUVAC models are 50% higher than those based on earlier solar EUV irradiance models. The calculations also show that for solar maximum conditions on 21 April 2002, most of the degradation of the escaping photoelectron flux takes place below 1000 km altitude.

  10. Laboratory 15 kV high voltage solar array facility

    NASA Technical Reports Server (NTRS)

    Kolecki, J. C.; Gooder, S. T.

    1976-01-01

    The laboratory high voltage solar array facility is a photoelectric power generating system. Consisting of nine modules with over 23,000 solar cells, the facility is capable of delivering more than a kilowatt of power. The physical and electrical characteristics of the facility are described.

  11. High efficiency solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, G. A.

    1995-01-01

    Understanding solar cell response to pulsed laser outputs is important for the evaluation of power beaming applications. The time response of high efficiency GaAs and silicon solar cells to a 25 nS monochromatic pulse input is described. The PC-1D computer code is used to analyze the cell current during and after the pulse for various conditions.

  12. Applications of ion implantation for high efficiency silicon solar cells

    NASA Technical Reports Server (NTRS)

    Minnucci, J. A.; Kirkpatrick, A. R.

    1977-01-01

    Ion implantation is utilized for the dopant introduction processes necessary to fabricate a silicon solar cell. Implantation provides a versatile powerful tool for development of high efficiency cells. Advantages and problems of implantation and the present status of developmental use of the technique for solar cells are discussed.

  13. Exploring Solar Power at Zion-Benton High

    ERIC Educational Resources Information Center

    Kasper, Rick

    1978-01-01

    Developed to provide students with actual hands-on experience in constructing energy-efficient homes and to increase the community's and students' knowledge of solar power as an alternate source of energy, a building trades program at a high school in Zion, Illinois has its students building single-family solar energy homes. (BM)

  14. Summary of high-efficiency solar-cell research

    NASA Technical Reports Server (NTRS)

    Kachare, R.

    1985-01-01

    High-efficiency solar-cell activities supporting efforts to achieve the DOE Five-Year Plan goals are summarized. Specific objectives are to identify and resolve key generic problems that limit cell efficiency to below theoretically predicted values and to design and fabricate cells having efficiences equal to or greater than 20% (AM1.5). Theoretical curves for various p-n junction cells were shown. The effects of practical barriers on cell efficiency was depicted along with the modeling parameters. Cell design parameters used in the analyses were described. The usefulness and present limitations of the existing modeling capabilities were presented. The historical evolution of the efficiencies of cells made from web and edge-defined film-fed growth (EFG) silicon ribbons were also described. The status of contemporary higher-efficiency technical capabilities and future activities to raise efficiencies were stated.

  15. Multifractal features of magnetospheric dynamics and their dependence on solar activity

    NASA Astrophysics Data System (ADS)

    Gopinath, Sumesh

    2016-09-01

    In the present study, novel wavelet leaders (WL) based multifractal analysis has been used to get a better knowledge of the self-organization phenomena inherent in complex magnetospheric dynamics during disturbance and quiescent periods, focusing mainly on the intermittent features of auroral electrojet (AE) index. The results derived from the analysis certainly exhibit the phase transition property of magnetosphere system with respect to variabilities in the driving conditions. By using the novel WL method, solar activity dependence/independence of intermittency of magnetospheric proxies such as AE, SYM-H and Dst indices have been compared. The results indicate that the multifractality of AE index does not follow the solar activity cycle while intermittent features of SYM-H and Dst indices show high degree of solar activity dependence. This shows that along with the external solar wind perturbations, certain complex phenomena of internal origin also significantly modulate the dynamics of geomagnetic fluctuations in the auroral region.

  16. Relationship between immunoglobulin levels and extremes of solar activity

    NASA Astrophysics Data System (ADS)

    Stoupel, Elijahu G.; Abramson, Eugene; Gabbay, Uri; Pick, Albert I.

    1995-06-01

    The possible relationship between epidemics and extremes of solar activity has been discussed previously. The purpose of the present study was to verify whether differences in the levels of immunoglobulins (IgA, IgG, IgM) could be noted at the highest (July 1989) and lowest (September 1986) points of the last (21st) and present (22nd) 11-year solar cycle. The work was divided into a 1-month study (covering the month of minimal or maximal solar activity), a 3-month study (1 month before and after the month of minimal or maximal solar activity) and a 5-month study (2 months before and after the month of minimal or maximal solar activity). A trend of a drop-off for all three immunoglobulins was seen on the far side of the maximal point of the solar cycle. Statistical significance was achieved in the 5-month study for IgM ( P=0.04), and a strong trend was shown for IgG ( P=0.07). Differences between the sexes were also noted.

  17. Printing highly efficient organic solar cells.

    PubMed

    Hoth, Claudia N; Schilinsky, Pavel; Choulis, Stelios A; Brabec, Christoph J

    2008-09-01

    The technological attraction in organic solar cells is their compatibility to printing processes. However, up to today, nearly no literature on "printed" organic solar cells have been published and the major body of the research work was done by spin coating or blading techniques. Transferring the spin-coating or doctor blading process currently used for the fabrication of bulk heterojunction solar cell to a printing process holds morphological challenges that have not been observed or reported up to today. We highlight these challenges and we show that inkjet printing of organic bulk heterojunction solar cells requires completely novel approaches and skill sets compared to the current state of the art. By adjusting the chemical properties of the poly(3-hexylthiophene) polymer donor and by using our recently developed inkjet solvent mixture, we have gained control over the nanomorphology of poly(3-hexylthiophene):fullerene blends during the printing process and report a new record power conversion efficiency of 3.5% for inkjet printed poly(3-hexylthiophene):fullerene based solar cells. PMID:18683989

  18. Physical mechanisms of solar activity effects in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Ebel, A.

    1989-01-01

    A great variety of physical mechanisms of possibly solar induced variations in the middle atmosphere has been discussed in the literature during the last decades. The views which have been put forward are often controversial in their physical consequences. The reason may be the complexity and non-linearity of the atmospheric response to comparatively weak forcing resulting from solar activity. Therefore this review focuses on aspects which seem to indicate nonlinear processes in the development of solar induced variations. Results from observations and numerical simulations are discussed.

  19. Microbial solar cells: applying photosynthetic and electrochemically active organisms.

    PubMed

    Strik, David P B T B; Timmers, Ruud A; Helder, Marjolein; Steinbusch, Kirsten J J; Hamelers, Hubertus V M; Buisman, Cees J N

    2011-01-01

    Microbial solar cells (MSCs) are recently developed technologies that utilize solar energy to produce electricity or chemicals. MSCs use photoautotrophic microorganisms or higher plants to harvest solar energy, and use electrochemically active microorganisms in the bioelectrochemical system to generate electrical current. Here, we review the principles and performance of various MSCs in an effort to identify the most promising systems, as well as the bottlenecks and potential solutions, for "real-life" MSC applications. We present an outlook on future applications based on the intrinsic advantages of MSCs, specifically highlighting how these living energy systems can facilitate the development of an electricity-producing green roof. PMID:21067833

  20. High-performance silicon nanohole solar cells.

    PubMed

    Peng, Kui-Qing; Wang, Xin; Li, Li; Wu, Xiao-Ling; Lee, Shuit-Tong

    2010-05-26

    We demonstrate Si nanohole arrays as a superior sunlight-absorbing nanostructure for photovoltaic solar cell applications. Under 1 sun AM1.5G illumination, a Si nanohole solar cell with p-n junctions via P diffusion exhibited a open-circuit voltage of 566.6 mV, a short-circuit current density of 32.2 mA/cm(2), and a remarkable power conversion efficiency of 9.51%, which is higher than that of its counterparts based on Si nanowires, planar Si, and pyramid-textured Si. The nanohole array geometry presents a novel and viable method fo cost-efficient solar energy conversion. PMID:20426468

  1. Investigation of relationships between parameters of solar nano-flares and solar activity

    NASA Astrophysics Data System (ADS)

    Safari, Hossein; Javaherian, Mohsen; Kaki, Bardia

    2016-07-01

    Solar flares are one of the important coronal events which are originated in solar magnetic activity. They release lots of energy during the interstellar medium, right after the trigger. Flare prediction can play main role in avoiding eventual damages on the Earth. Here, to interpret solar large-scale events (e.g., flares), we investigate relationships between small-scale events (nano-flares) and large-scale events (e.g., flares). In our method, by using simulations of nano-flares based on Monte Carlo method, the intensity time series of nano-flares are simulated. Then, the solar full disk images taken at 171 angstrom recorded by SDO/AIA are employed. Some parts of the solar disk (quiet Sun (QS), coronal holes (CHs), and active regions (ARs)) are cropped and the time series of these regions are extracted. To compare the simulated intensity time series of nano-flares with the intensity time series of real data extracted from different parts of the Sun, the artificial neural networks is employed. Therefore, we are able to extract physical parameters of nano-flares like both kick and decay rate lifetime, and the power of their power-law distributions. The procedure of variations in the power value of power-law distributions within QS, CH is similar to AR. Thus, by observing the small part of the Sun, we can follow the procedure of solar activity.

  2. Vacancy associates promoting solar-driven photocatalytic activity of ultrathin bismuth oxychloride nanosheets.

    PubMed

    Guan, Meili; Xiao, Chong; Zhang, Jie; Fan, Shaojuan; An, Ran; Cheng, Qingmei; Xie, Junfeng; Zhou, Min; Ye, Bangjiao; Xie, Yi

    2013-07-17

    Crystal facet engineering of semiconductors is of growing interest and an important strategy for fine-tuning solar-driven photocatalytic activity. However, the primary factor in the exposed active facets that determines the photocatalytic property is still elusive. Herein, we have experimentally achieved high solar photocatalytic activity in ultrathin BiOCl nanosheets with almost fully exposed active {001} facets and provide some new and deep-seated insights into how the defects in the exposed active facets affect the solar-driven photocatalytic property. As the thickness of the nanosheets reduces to atomic scale, the predominant defects change from isolated defects V(Bi)‴ to triple vacancy associates V(Bi)‴V(O)••V(Bi)‴, which is unambiguously confirmed by the positron annihilation spectra. By virtue of the synergic advantages of enhanced adsorption capability, effective separation of electron–hole pairs and more reductive photoexcited electrons benefited from the V(Bi)‴V(O)••V(Bi)‴ vacancy associates, the ultrathin BiOCl nanosheets show significantly promoted solar-driven photocatalytic activity, even with extremely low photocatalyst loading. The finding of the existence of distinct defects (different from those in bulks) in ultrathin nanosheets undoubtedly leads to new possibilities for photocatalyst design using quasi-two-dimensional materials with high solar-driven photocatalytic activity. PMID:23782301

  3. Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

    NASA Astrophysics Data System (ADS)

    Dinetta, L. C.; Hannon, M. H.

    1995-10-01

    Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual

  4. Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

    NASA Technical Reports Server (NTRS)

    Dinetta, L. C.; Hannon, M. H.

    1995-01-01

    Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual

  5. Self-similar signature of the active solar corona within the inertial range of solar-wind turbulence.

    PubMed

    Kiyani, K; Chapman, S C; Hnat, B; Nicol, R M

    2007-05-25

    We quantify the scaling of magnetic energy density in the inertial range of solar-wind turbulence seen in situ at 1 AU with respect to solar activity. At solar maximum, when the coronal magnetic field is dynamic and topologically complex, we find self-similar scaling in the solar wind, whereas at solar minimum, when the coronal fields are more ordered, we find multifractality. This quantifies the solar-wind signature that is of direct coronal origin and distinguishes it from that of local MHD turbulence, with quantitative implications for coronal heating of the solar wind. PMID:17677760

  6. Possible relationships between solar activity and meteorological phenomena

    NASA Technical Reports Server (NTRS)

    Bandeen, W. R. (Editor); Maran, S. P. (Editor)

    1975-01-01

    A symposium was conducted in which the following questions were discussed: (1) the evidence concerning possible relationships between solar activity and meteorological phenomena; (2) plausible physical mechanisms to explain these relationships; and (3) kinds of critical measurements needed to determine the nature of solar/meteorological relationships and/or the mechanisms to explain them, and which of these measurements can be accomplished best from space.

  7. High temperature - low mass solar blanket

    NASA Technical Reports Server (NTRS)

    Mesch, H. G.

    1979-01-01

    Interconnect materials and designs for use with ultrathin silicon solar cells are discussed, as well as the results of an investigation of the applicability of parallel-gap resistance welding for interconnecting these cells. Data relating contact pull strength and cell electrical degradation to variations in welding parameters such as time, voltage and pressure are presented. Methods for bonding ultrathin cells to flexible substances and for bonding thin (75 micrometers) covers to these cells are described. Also, factors influencing fabrication yield and approaches for increasing yield are discussed. The results of vacuum thermal cycling and thermal soak tests on prototype ultrathin cell test coupons and one solar module blanket are presented.

  8. High performance polymer tandem solar cell

    PubMed Central

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

    2015-01-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells. PMID:26669577

  9. High throughput solar cell ablation system

    SciTech Connect

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2014-10-14

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  10. High throughput solar cell ablation system

    SciTech Connect

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2012-09-11

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  11. High performance polymer tandem solar cell

    NASA Astrophysics Data System (ADS)

    da Silva, Wilson Jose; Schneider, Fabio Kurt; Mohd Yusoff, Abd. Rashid Bin; Jang, Jin

    2015-12-01

    A power conversion efficiency of 9.02% is obtained for a fully solution-processed polymer tandem solar cell, based on the diketopyrrolopyrrole unit polymer as a low bandgap photoactive material in the rear subcell, in conjunction with a new robust interconnecting layer. This interconnecting layer is optically transparent, electrically conductive, and physically strong, thus, the charges can be collected and recombined in the interconnecting layer under illumination, while the charge is generated and extracted under dark conditions. This indicates that careful interface engineering of the charge-carrier transport layer is a useful approach to further improve the performance of polymer tandem solar cells.

  12. General overview of the solar activity effects on the lower ionosphere

    NASA Technical Reports Server (NTRS)

    Danilov, A. D.

    1989-01-01

    Solar activity influences the ionospheric D region. That influence manifests itself both in the form of various solar induced disturbances and in the form of the D region dependence on solar activity parameters (UV-flux, interplanetary magnetic field, solar wind etc.) in quiet conditions. Relationship between solar activity and meteorological control of the D region behavior is considered in detail and examples of strong variations of aeronomical parameters due to solar or meteorological events are given.

  13. High-precision analysis of the solar twin HIP 100963

    NASA Astrophysics Data System (ADS)

    Galarza, Jhon Yana; Meléndez, Jorge; Ramírez, Ivan; Yong, David; Karakas, Amanda I.; Asplund, Martin; Liu, Fan

    2016-04-01

    Context. HIP 100963 was one of the first solar twins identified. Although some high-precision analyses are available, a comprehensive high-precision study of chemical elements from different nucleosynthetic sources is still lacking from which to obtain potential new insights on planets, stellar evolution, and Galactic chemical evolution (GCE). Aims: We analyze and investigate the origin of the abundance pattern of HIP 100963 in detail, in particular the pattern of the light element Li, the volatile and refractory elements, and heavy elements from the s- and r-processes. Methods: We used the HIRES spectrograph on the Keck I telescope to acquire high-resolution (R ≈ 70 000) spectra with a high signal-to-noise ratio (S/N ≈ 400-650 per pixel) of HIP 100963 and the Sun for a differential abundance analysis. We measured the equivalent widths (EWs) of iron lines to determine the stellar parameters by employing the differential spectroscopic equilibrium. We determined the composition of volatile, refractory, and neutron-capture elements through a differential abundance analysis with respect to the Sun. Results: The stellar parameters we found are Teff = 5818 ± 4 K, log g = 4.49 ± 0.01 dex, vt = 1.03 ± 0.01km s-1, and [Fe/H] = -0.003 ± 0.004 dex. These low errors allow us to compute a precise mass (1.03+0.02-0.01 M⊙) and age (2.0 ± 0.4 Gyr), obtained using Yonsei-Yale isochrones. Using our [Y/Mg] ratio, we have determined an age of 2.1 ± 0.4 Gyr, in agreement with the age computed using isochrones. Our isochronal age also agrees with the age determined from stellar activity (2.4 ± 0.3 Gyr). We study the abundance pattern with condensation temperature (Tcond) taking corrections by the GCE into account. We show that the enhancements of neutron-capture elements are explained by contributions from both the s- and r-process. The lithium abundance follows the tight Li-age correlation seen in other solar twins. Conclusions: We confirm that HIP 100963 is a solar twin

  14. High-precision analysis of the solar twin HIP 100963

    NASA Astrophysics Data System (ADS)

    Galarza, Jhon Yana; Meléndez, Jorge; Ramírez, Ivan; Yong, David; Karakas, Amanda I.; Asplund, Martin; Liu, Fan

    2016-05-01

    Context. HIP 100963 was one of the first solar twins identified. Although some high-precision analyses are available, a comprehensive high-precision study of chemical elements from different nucleosynthetic sources is still lacking from which to obtain potential new insights on planets, stellar evolution, and Galactic chemical evolution (GCE). Aims: We analyze and investigate the origin of the abundance pattern of HIP 100963 in detail, in particular the pattern of the light element Li, the volatile and refractory elements, and heavy elements from the s- and r-processes. Methods: We used the HIRES spectrograph on the Keck I telescope to acquire high-resolution (R ≈ 70 000) spectra with a high signal-to-noise ratio (S/N ≈ 400-650 per pixel) of HIP 100963 and the Sun for a differential abundance analysis. We measured the equivalent widths (EWs) of iron lines to determine the stellar parameters by employing the differential spectroscopic equilibrium. We determined the composition of volatile, refractory, and neutron-capture elements through a differential abundance analysis with respect to the Sun. Results: The stellar parameters we found are Teff = 5818 ± 4 K, log g = 4.49 ± 0.01 dex, vt = 1.03 ± 0.01km s-1, and [Fe/H] = -0.003 ± 0.004 dex. These low errors allow us to compute a precise mass (1.03+0.02-0.01 M⊙) and age (2.0 ± 0.4 Gyr), obtained using Yonsei-Yale isochrones. Using our [Y/Mg] ratio, we have determined an age of 2.1 ± 0.4 Gyr, in agreement with the age computed using isochrones. Our isochronal age also agrees with the age determined from stellar activity (2.4 ± 0.3 Gyr). We study the abundance pattern with condensation temperature (Tcond) taking corrections by the GCE into account. We show that the enhancements of neutron-capture elements are explained by contributions from both the s- and r-process. The lithium abundance follows the tight Li-age correlation seen in other solar twins. Conclusions: We confirm that HIP 100963 is a solar twin

  15. Space solar cells - High efficiency and radiation damage

    NASA Technical Reports Server (NTRS)

    Brandhorst, H. W., Jr.; Bernatowicz, D. T.

    1980-01-01

    The proceedings of the Third Solar Cell High Efficiency and Radiation Damage Meeting are outlined. The topics covered included high efficiency silicon solar cells, silicon solar cell radiation damage, GaAs solar cell performance, and 30 percent conversion devices. The study of radiation damage from a fundamental defect-centered basis is discussed and evaluated as a focus of future work. 18% AM0 efficiency and 0.7 V open-circuit voltages are designated as achievable goals for silicon solar cells, and the potential for 30% AM0 efficiencies from monolithic tandem cell designs without sunlight concentration is noted. In addition to its potential for 20% AM0 efficiencies, the GaAs cell offers the possibility of a radiation-insensitive power supply when operated at temperatures near 200 C.

  16. High-Efficiency Solar Cell Concepts: Physics, Materials, and Devices

    SciTech Connect

    Mascarenhas, A.; Francoeur, S.; Seong, M. J.; Fluegel, B.; Zhang, Y.; Wanlass, M. W.

    2005-01-01

    Over the past three decades, significant progress has been made in the area of high-efficiency multijunction solar cells, with the effort primarily directed at current-matched solar cells in tandem. The key materials issues here have been obtaining semiconductors with the required bandgaps for sequential absorption of light in the solar spectrum and that are lattice matched to readily available substrates. The GaInP/GaAs/Ge cell is a striking example of success achieved in this area. Recently, several new approaches for high-efficiency solar cell design have emerged, that involve novel methods for tailoring alloy bandgaps, as well as alternate technologies for hetero-epitaxy of III-V's on Si. The advantages and difficulties expected to be encountered with each approach will be discussed, addressing both the materials issues and device physics whilst contrasting them with other fourth-generation solar cell concepts.

  17. Measurements of High-Degree Solar Oscillation Parameters

    NASA Astrophysics Data System (ADS)

    Bachmann, K. T.; Duvall, T. L., Jr.; Harvey, J. W.; Hill, F.

    1994-12-01

    We present results obtained from full-disk, 1000times 1024 pixel, Ca II intensity images of the Sun collected with the High-L Helioseismometer (HLH). Our measurement of p- and f-mode oscillation frequencies over the frequency range 1.8<=nu <=5.0 mHz and the spherical harmonic degree range 100<=l<=1200 from 22-25 June 1993 data represents an improvement over previous measurements. We are able to differentiate among the predictions of several solar models, thus constraining physical models of the solar convection zone. We also include recent splitting and frequency results from data collected during the entire month of June 1994. The purpose of the HLH research program is to measure high-degree solar oscillation parameters for the remainder of this decade in support of the Solar Oscillations Investigation - Michelson Doppler Imager collaboration, which is part of the Solar and Heliospheric Observatory, a joint ESA-NASA satellite mission.

  18. High temperature solar thermal technology: The North Africa Market

    SciTech Connect

    Not Available

    1990-12-01

    High temperature solar thermal (HTST) technology offers an attractive option for both industrialized and non-industrialized countries to generate electricity and industrial process steam. The purpose of this report is to assess the potential market for solar thermal applications in the North African countries of Algeria, Egypt, Morocco and Tunisia. North Africa was selected because of its outstanding solar resource base and the variety of applications to be found there. Diminishing oil and gas resources, coupled with expanding energy needs, opens a large potential market for the US industry. The US high temperature solar trough industry has little competition globally and could build a large market in these areas. The US is already familiar with certain solar markets in North Africa due to the supplying of substantial quantities of US-manufactured flat plate collectors to this region.

  19. Conversion Tower for Dispatchable Solar Power: High-Efficiency Solar-Electric Conversion Power Tower

    SciTech Connect

    2012-01-11

    HEATS Project: Abengoa Solar is developing a high-efficiency solar-electric conversion tower to enable low-cost, fully dispatchable solar energy generation. Abengoa’s conversion tower utilizes new system architecture and a two-phase thermal energy storage media with an efficient supercritical carbon dioxide (CO2) power cycle. The company is using a high-temperature heat-transfer fluid with a phase change in between its hot and cold operating temperature. The fluid serves as a heat storage material and is cheaper and more efficient than conventional heat-storage materials, like molten salt. It also allows the use of a high heat flux solar receiver, advanced high thermal energy density storage, and more efficient power cycles.

  20. Solar activity: The Sun as an X-ray star

    NASA Technical Reports Server (NTRS)

    Golub, L.

    1981-01-01

    The existence and constant activity of the Sun's outer atmosphere are thought to be due to the continual emergence of magnetic fields from the Solar interior and the stressing of these fields at or near the surface layers of the Sun. The structure and activity of the corona are thus symptomatic of the underlying magnetic dynamo and the existence of an outer turbulent convective zone on the Sun. A sufficient condition for the existence of coronal activity on other stars would be the existence of a magnetic dynamo and an outer convective zone. The theoretical relationship between magnetic fields and coronal activity can be tested by Solar observations, for which the individual loop structures can be resolved. A number of parameters however, which enter into the alternative theoretical formulations remain fixed in all Solar observations. To determine whether these are truly parameters of the theory observations need to be extended to nearby stars on which suitable conditions may occur.

  1. Semiannual variation of the geomagnetic activity and solar wind parameters

    NASA Astrophysics Data System (ADS)

    Orlando, M.; Moreno, G.; Parisi, M.; Storini, M.

    1993-10-01

    The semiannual variation of the geomagnetic activity is investigated in connection with a large set of solar wind and interplanetary magnetic field data (4494 daily averages from 1965 to 1987). Our analysis confirms that the geomagnetic activity (described by the aa index), is mainly modulated by the southward component of the magnetic field (BS), as suggested by Russell and McPherron. On the other hand, it is also found that the solar wind velocity (V) has a relevant role in this phenomenon. In fact, the amplitude of the aa modulation is best correlated with the function BSV2. We also explore the linkage between the annual trend of aa and the sunspot activity (1868-1989), showing that the modulation of the geomagnetic activity follows a more regular pattern during the descending phase of the solar cycle than during the rising and maximum parts.

  2. HIGH LATITUDE ULYSSES OBSERVATIONS OF THE H/HE INTENSITY RATIO UNDER SOLAR MINIMUM AND SOLAR MAXIMUM CONDITIONS

    SciTech Connect

    J. GOSLING; D. LARIO; ET AL

    2001-03-01

    We analyze measurements of the 0.5-1.0 MeV/nucleon H/He intensity ratio from the Ulysses spacecraft during its first (1992-94) and second (1999-2000) ascent to southern high latitude regions of the heliosphere. These cover a broad range of heliocentric distances (from 5.2 to 2.0 AU) and out-of-ecliptic latitudes (from 18{degree}S to 80{degree}S). During Ulysses' first southern pass, the HI-SCALE instrument measured a series of enhanced particle fluxes associated with the passage of a recurrent corotating interaction region (CIR). Low values ({approximately}6) of the H/He ratio were observed in these recurrent corotating events, with a clear minimum following the passage of the corotating reverse shock. When Ulysses reached high southern latitudes (>40{degree}S), the H/He ratio always remained below {approximately}10 except during two transient solar events that brought the ratio to high (>20) values. Ulysses' second southern pass was characterized by a higher average value of the H/He ratio. No recurrent pattern was observed in the energetic ion intensity which was dominated by the occurrence of transient events of solar origin. Numerous CIRs, many of which were bounded by forward and reverse shock pairs, were still observed in the solar wind and magnetic field data. The arrival of those CIRs at Ulysses did not always result in a decrease of the H/He ratio; on the contrary, many CIRs showed a higher H/He ratio than some transient events. Within a CIR, however, the H/He ratio usually increased around the forward shock and decreased towards the reverse shock. Throughout the second ascent to southern heliolatitudes, the H/He ratio seldom decreased below {approximately}10 even at high latitudes (>40{degree}S). We interpret these higher values of the H/He ratio in terms of the increasing level of solar activity together with the poor definition and short life that corotating solar wind structures have under solar maximum conditions. The global filling of the heliosphere

  3. Intraocular pressure (IOP) in relation to four levels of daily geomagnetic and extreme yearly solar activity.

    PubMed

    Stoupel, E; Goldenfeld, M; Shimshoni, M; Siegel, R

    1993-02-01

    The link between geomagnetic field activity (GMA), solar activity and intraocular pressure (IOP) in healthy individuals was investigated. The IOP of 485 patients (970 eyes) was recorded over three nonconsecutive years (1979, 1986, 1989) which were characterized by maximal solar activity (1979, 1989) or minimal solar activity (1986). The measurements were also correlated with four categories of GMA activity: quiet (level I0), unsettled (II0), active (III0), and stormy (IV0). Participants were also differentiated by age and sex. We found that IOP was lowest on days of level IV0 (stromy) GMA. The drop in IOP concomitant with a decrease in GMA level was more significant during periods of low solar activity and in persons over 65 years of age. There was a trend towards higher IOP values on days of levels II0 and IV0 GMA in years of high solar activity. Differences between the sexes and among individuals younger than 65 years were not significant. Our results show an interesting aspect of environmental influence on the healthy population. PMID:8468099

  4. Windowless High-Pressure Solar Reactor

    NASA Technical Reports Server (NTRS)

    Ramohalli, K. N. R.

    1985-01-01

    Obscuration by reaction products eliminated. Chemical reactor heated by Sunlight employs rocket technology to maintain internal pressure. Instead of keeping chamber tightly closed, pressure maintained by momentum balance between incoming and outgoing materials. Windowless solar reactor admits concentrated Sunlight through exhaust aperture. Pressure in reactor maintained dynamically.

  5. Variability of foE in the equatorial ionosphere with solar activity

    NASA Astrophysics Data System (ADS)

    Abe, O. E.; Rabiu, A. B.; Adeniyi, J. O.

    2013-01-01

    This research examined the variability of foE in the equatorial ionosphere with solar activity within the equatorial ionospheric anomaly region. Ionosonde data recorded at Ouagadougou (lat. 12.4°N, long. 1.5°W and magnetic dip 1.43°N) were engaged to study the transient variations of the critical frequency of the E-layer (foE) and its dependence on solar activity. The study revealed that foE increases with the increase in solar intensity of the sun. The variability of the foE decreases with increases in the solar activity. The maximum value of the foE is at local noon when the ionosphere is stable; the variability at this local time is minimal. The minimum value of the foE is at sunrise and sunset, at this period on local time the equatorial ionosphere recorded its maxima variability. Irrespective of the degree of solar activity, foE is observed to be maximum in June solstice, followed by the equinoxes and minimum in December solstice. Equinoctial asymmetry occurred in the variation of the relative standard deviation of foE with maximum in September/March equinox for low/high solar activity.

  6. Highly stable tandem solar cell monolithically integrating dye-sensitized and CIGS solar cells

    PubMed Central

    Chae, Sang Youn; Park, Se Jin; Joo, Oh-Shim; Jun, Yongseok; Min, Byoung Koun; Hwang, Yun Jeong

    2016-01-01

    A highly stable monolithic tandem solar cell was developed by combining the heterogeneous photovoltaic technologies of dye-sensitized solar cell (DSSC) and solution-processed CuInxGa1-xSeyS1-y (CIGS) thin film solar cells. The durability of the tandem cell was dramatically enhanced by replacing the redox couple from to [Co(bpy)3]2+ /[Co(bpy)3]3+), accompanied by a well-matched counter electrode (PEDOT:PSS) and sensitizer (Y123). A 1000 h durability test of the DSSC/CIGS tandem solar cell in ambient conditions resulted in only a 5% decrease in solar cell efficiency. Based on electrochemical impedance spectroscopy and photoelectrochemical cell measurement, the enhanced stability of the tandem cell is attributed to minimal corrosion by the cobalt-based polypyridine complex redox couple. PMID:27489138

  7. Highly stable tandem solar cell monolithically integrating dye-sensitized and CIGS solar cells

    NASA Astrophysics Data System (ADS)

    Chae, Sang Youn; Park, Se Jin; Joo, Oh-Shim; Jun, Yongseok; Min, Byoung Koun; Hwang, Yun Jeong

    2016-08-01

    A highly stable monolithic tandem solar cell was developed by combining the heterogeneous photovoltaic technologies of dye-sensitized solar cell (DSSC) and solution-processed CuInxGa1-xSeyS1-y (CIGS) thin film solar cells. The durability of the tandem cell was dramatically enhanced by replacing the redox couple from to [Co(bpy)3]2+ /[Co(bpy)3]3+), accompanied by a well-matched counter electrode (PEDOT:PSS) and sensitizer (Y123). A 1000 h durability test of the DSSC/CIGS tandem solar cell in ambient conditions resulted in only a 5% decrease in solar cell efficiency. Based on electrochemical impedance spectroscopy and photoelectrochemical cell measurement, the enhanced stability of the tandem cell is attributed to minimal corrosion by the cobalt-based polypyridine complex redox couple.

  8. Inferred flows of electric currents in solar active regions

    NASA Technical Reports Server (NTRS)

    Ding, Y. J.; Hong, Q. F.; Hagyard, M. J.; Deloach, A. C.

    1985-01-01

    Techniques to identify sources of major current systems in active regions and their channels of flow are explored. Measured photospheric vector magnetic fields together with high resolution white light and H-alpha photographs provide the data base to derive the current systems in the photosphere and chromosphere of a solar active region. Simple mathematical constructions of active region fields and currents are used to interpret these data under the assumptions that the fields in the lower atmosphere (below 200 km) may not be force free but those in the chromosphere and higher are. The results obtained for the complex active region AR 2372 are: (1) Spots exhibiting significant spiral structure in the penumbral filaments were the source of vertical currents at the photospheric surface; (2) Magnetic neutral lines where the transverse magnetic field was strongly sheared were channels along which a strong current system flowed; (3) The inferred current systems produced a neutral sheet and oppositely-flowing currents in the area of the magnetic delta configuration that was the site of flaring.

  9. Relation Between Myocardial Infarction Deaths and Solar Activity in Mexico

    NASA Astrophysics Data System (ADS)

    Diaz-Sandoval, R.

    2002-05-01

    We study the daily incidence of myocardial infarction deaths in Mexico for 4 years (1996-99) with a total of 129 917 cases in all the country, collected at the General Directorate of Epidemiology (National Ministry of Health). We divided the cases by sex and age and perform two kinds of analysis. First, we did an spectral analysis using the Maximum Entropy Method, considering the complete period, and minimum and maximum epochs of solar activity. The results show that the most persistent periodicity at higher frequencies in the myocardial infarction death occurrence is that of seven days. Considering the solar cycle phases, we found that during solar minimum times some frequencies are not detectable compared with solar maximum epochs, particularly that of seven days. Biological rhythms close to seven days, the circaseptans, are in general thought to be only the result of the social organization of life. However, this cannot be the only explanation, because the 7-days periodicity has been encountered in lower organisms not related with our rhythms of life. Thus, it has been proposed that biological rhythms could be evolutionary adaptations to environmental conditions, particularly, solar activity. In the second analysis we compared two solar activity-related phenomena: the Forbush decreases of cosmic rays and the geomagnetic index Ap for various levels of geomagnetic perturbations. The results show that during decreases of cosmic ray fluxes, for most cases there is a higher average myocardial infarction deaths occurrence, compared with the average incidence in days of no decreases. For geomagnetic activity we find the same situation in most cases. Furthermore, this behavior is more pronounced as the level of the perturbation increases and in times of maximum solar activity.

  10. Impact of Solar Proton Events on High Latitude Ionospheric Conditions

    NASA Astrophysics Data System (ADS)

    Aslam, A. M.; Gwal, Ashok Kumar; Mansoori, Azad Ahmad

    2016-07-01

    We investigate the ionospheric response to the solar protons which are accelerated to different energies (MeV-GeV) and thought to be originated at the solar atmosphere during the various energetic phenomena knows as solar transients viz. Solar Flares, Coronal Mass Ejections (CMEs). These transients are believed to be a manifestation of same energy release processes from a highly complex condition in the magnetic field configuration on the solar surface. We have taken six solar proton events (SPE) of solar cycle 23rd for analysis in the various energy bands of the protons. In order to find the ionospheric responses to these incoming solar protons ionospheric total electron content (TEC) is taken as the characteristic parameter. We have taken the data observed by GOES satellites which provides the data for different energy channels (0.8-4 MeV, 4-9 MeV, 9-15 MeV, 15-40 MeV, 40-80 MeV, 80-165 MeV, and 165-500 MeV). The enhancement in peak TEC (∆TEC) was then obtained for the high latitude station Davis (Lat-68.35, Lon 77.58). To find the association of this enhancement with proton flux characteristics we derived the correspondence between spectral indices and ∆TEC. We obtained a strong correlation (0.84) to exist between the spectral indices and ∆TEC.

  11. Development of high-efficiency solar cells on silicon web

    NASA Technical Reports Server (NTRS)

    Rohatgi, A.; Meier, D. L.; Campbell, R. B.; Seidensticker, R. G.; Rai-Choudhury, P.

    1984-01-01

    The development of high efficiency solar cells on a silicon web is discussed. Heat treatment effects on web quality; the influence of twin plane lamellae, trace impurities and stress on minority carrier lifetime; and the fabrication of cells are discussed.

  12. Short-term changes in solar oscillation frequencies and solar activity

    NASA Technical Reports Server (NTRS)

    Woodard, M. F.; Libbrecht, K. G.; Kuhn, J. R.; Murray, N.

    1991-01-01

    It is shown that the frequencies of solar rho-mode oscillations change significantly over periods as short as one month. These changes correlate significantly with variations in the strength of surface solar activity as measured by the average, over the sun's visible surface, of the magnitude of the line-of-sight magnetic field component from magnetograms. The frequency and mean magnetic variations are found to obey a linear relationship. It is seen that the mean frequency shift at any time depends on the history of solar activity over an interval of, at most, several months prior to the measurement and conclude that the dominant mechanism of the frequency shift is correlated with surface magnetic activity.

  13. Systematic process development towards high performance transferred thin silicon solar cells based on epitaxially grown absorbers

    NASA Astrophysics Data System (ADS)

    Murcia Salazar, Clara Paola

    The value of thin crystalline silicon (c-Si) solar cells is the potential for higher performance compared to conventional wafer approaches. Thin silicon solar cells can outperform thick cells with the same material properties because the smaller active volume causes a reduced bulk recombination leading to higher voltages while efficient light trapping structures ensure all photons are absorbed. Efficiencies above 20+% can be achieved with less than 20um of c-Si with current silicon solar cell processing technologies. In a thin solar cell, factors that will lead to high efficiency include high minority carrier lifetime, low surface recombination, and good optical confinement. Independently optimizing surface optical and electrical properties in a thin solar cell can achieve this higher performance. In addition, re-utilizing a c-Si wafer with a process that allows optimization of both surfaces is a path to higher performance at lower cost. The challenge in the fabrication of this high performance concept is to separately analyze critical parameters through fabrication and transfer and establish the design rules for high performance. This work contributes to the design and systematic fabrication approach of a 20 mum thick epitaxial silicon solar cell. State-of-the-art thin absorbers of less than 30um have reported 655mV (on a textured front surface with antireflection coating), and efficiencies near 17%. We report near 640mV (on a planar front surface with antireflection coating) for 20 mum thick absorbers. It is found that previously reported efficiencies are tightly related to solar cell's active thickness. In the case of transferred solar cells, the thinnest epitaxial transferred cell reported is near 24 mum thick with an efficiency of 15.4% (transparent front handle, textured with ARC and metallic back reflector). Recently, a c-Si transferred solar cell of 43 mum has reported 19.1% efficiency (with a front texture and ARC with localized back contact and reflector

  14. Observations of Cosmic Rays and Solar Energetic Particles from the Ulysses COSPIN High Energy Telescope Following Completion of the Solar Maximum Solar Polar Passes.*

    NASA Astrophysics Data System (ADS)

    McKibben, R. B.; Lopate, C.; Connell, J. J.; Posner, A.

    2003-04-01

    At the end of 2002, following its second pass over the Sun's north polar region, Ulysses had reached a radial distance of about 4.5 AU at a heliographic latitude of 24°N. While solar activity remained high, the modulated intensity of cosmic rays observed by Ulysses’ COSPIN High Energy Telescope had increased significantly from the levels observed early in 2001, which most likely represented the maximum modulation for this solar cycle. Despite continuing solar activity, the new qA<0 magnetic polarity of the Sun's dipole field was fully established for both poles since the change in the North Pole polarity in 2000. Although the current sheet tilt was still large (>40° as reported by the Wilcox Solar Observatory) and the solar wind was still frequently disturbed by solar activity, it is worthwhile to examine the recent increase in the quiet-time cosmic ray fluxes for evidence of the change in latitudinal gradients expected upon change of magnetic polarity. A difficulty is the lack of a well-matched 1 AU base-line to help distinguish spatial from temporal variations following the termination of IMP-8 operations in late 2001. We will summarize Ulysses observations of energetic (>~30 MeV/n) protons and helium through the most recent available data, and will discuss available options for determining baseline fluxes at 1 AU for studies of the radial and latitudinal gradients. **This work was supported in part by NASA/JPL Contract 955432, by NASA Grant NASA 5-28516 and by NSF grant ATM 99-12341.

  15. IS THE CURRENT LACK OF SOLAR ACTIVITY ONLY SKIN DEEP?

    SciTech Connect

    Broomhall, A.-M.; Chaplin, W. J.; Elsworth, Y.; Fletcher, S. T.; New, R. E-mail: wjc@bison.ph.bham.ac.uk E-mail: S.Fletcher@shu.ac.uk

    2009-08-01

    The Sun is a variable star whose magnetic activity and total irradiance vary on a timescale of approximately 11 years. The current activity minimum has attracted considerable interest because of its unusual duration and depth. This raises the question: what might be happening beneath the surface where the magnetic activity ultimately originates? The surface activity can be linked to the conditions in the solar interior by the observation and analysis of the frequencies of the Sun's natural seismic modes of oscillation-the p modes. These seismic frequencies respond to changes in activity and are probes of conditions within the Sun. The Birmingham Solar-Oscillations Network (BiSON) has made measurements of p-mode frequencies over the last three solar activity cycles, and so is in a unique position to explore the current unusual and extended solar minimum. We show that the BiSON data reveal significant variations of the p-mode frequencies during the current minimum. This is in marked contrast to the surface activity observations, which show little variation over the same period. The level of the minimum is significantly deeper in the p-mode frequencies than in the surface observations. We observe a quasi-biennial signal in the p-mode frequencies, which has not previously been observed at mid- and low-activity levels. The stark differences in the behavior of the frequencies and the surface activity measures point to activity-related processes occurring in the solar interior, which are yet to reach the surface, where they may be attenuated.

  16. CORONAS-F Project: The Study of Solar Activity and Its Effects on the Earth

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. D.

    The CORONAS-F space mission is characterized in general terms as part of the Russian CORONAS space project aimed at the study of solar activity and solar-terrestrial coupling. The composition of the scientific payload and the basic characteristic of the instruments are described. Some observations carried out on board the CORONAS-F satellite are discussed, including global oscillations of the Sun, active regions, flares and mass ejections, high-energy particles in near-Earth space, etc. The results of investigation of the Earth's upper atmosphere are provided as obtained from the analysis of the absorption of solar hard X-rays at shadow entry and shadow exit of the satellite, as well as the night glow events caused by solar radiation fluxes, galactic cosmic rays, and precipitations of charged particles from the magnetosphere.

  17. Some problems in coupling solar activity to meteorological phenomena

    NASA Technical Reports Server (NTRS)

    Dessler, A. J.

    1974-01-01

    The development of a theory of coupling of solar activity to meteorological phenomena has to date foundered on the two difficulties of (1) devising a mechanism that can modify the behavior of the troposphere while employing only a negligible amount of energy compared with the energy necessary to drive the normal meteorological system; and (2) determining how such a mechanism can effectively couple some relevant magnetospheric process into the troposphere in such a way as to influence the weather. A clue to the nature of the interaction between the weather and solar activity might be provided by the fact that most solar activity undergoes a definite 11-year cycle, while meteorological phenomena undergo either no closely correlated variation, or an 11-year variation, or a 22-year variation.

  18. Some problems in coupling solar activity to meteorological phenomena

    NASA Technical Reports Server (NTRS)

    Dessler, A. J.

    1975-01-01

    The development of a theory of coupling of solar activity to meteorological phenomena is hindered by the difficulties of devising a mechanism that can modify the behavior of the troposphere while employing only a negligible amount of energy compared with the energy necessary to drive the normal meteorological system, and determining how such a mechanism can effectively couple some relevant magnetospheric process into the troposphere in such a way as to influence the weather. A clue to the nature of the interaction between the weather and solar activity might be provided by the fact that most solar activity undergoes a definite 11-yr cycle, and meteorological phenomena undergo either no closely correlated variation, an 11-yr variation, or a 22-yr variation.

  19. Correlation of nighttime MF signal strength with solar activity

    NASA Astrophysics Data System (ADS)

    Kohata, Hiroki; Kimura, Iwane; Wakai, Noboru; Ogawa, Tadahiko

    Observations of the signal strength of MF broadcasting signals (774/770 kHz) transmitted from Akita, Japan, on board the Japanese Antarctic ice breaker Fuji, bound from Japan to Syowa station, Antarctica, have revealed an interesting positive correlation between strengths of long distance signals propagating at night and solar activity. It is already known that MF propagation characteristics in North America show a negative correlation with solar activity. The present paper, interprets the results by using the multihop method with full-wave analysis. The difference in correlation with solar activity between the results of Fuji and those in North America can be elucidated if it is assumed that there is a ledge in the electron-density profile around an altitude range of 85 to 90 km and that the density of the ledge is smaller in the North American region than in the equatorial region.

  20. A prediction of geomagnetic activity for solar cycle 23

    NASA Astrophysics Data System (ADS)

    Cliver, E. W.; Ling, A. G.; Wise, J. E.; Lanzerotti, L. J.

    1999-04-01

    Using a database of 13 solar cycles of geomagnetic aa data, we obtained correlations between cycle averages of geomagnetic activity (and sunspot number) and the numbers of days with disturbance levels above certain aa thresholds. We then used a precursor-type relation to predict an average aa index of 23.1 nT for cycle 23 and inserted this average aa value into the above correlations to forecast the integral size distribution of geomagnetic activity for the new cycle. The predicted size distribution is similar to that observed for cycles 21 and 22 but most closely resembles that of solar cycle 18 (1944-1954), which was slightly smaller than cycles 21 and 22. Our prediction agrees reasonably well with the ``climatology-based'' forecast made by the intergovernmental panel tasked to predict geomagnetic activity for the coming solar cycle and is significantly different from their ``precursor-based'' prediction.

  1. High-efficiency solar cells based on micro-nano scale structures

    NASA Astrophysics Data System (ADS)

    Dutta, Achyut K.; Olah, Robert; Mizuno, Genki; Sengupta, Rabi; Park, Jin-Hong; Wijewarnasuriya, Priyalal; Dhar, Nibir K.

    2010-04-01

    Higher efficiency solar cells are required to reduce solar array mass, stowed volume, and cost for numerous commercial and military applications. Conventional solar cell made of thin-film or crystal-Si (c-Si) or other thin films have limited conversion efficiency of 10 to 20% with the cost of 3-5/Wp. Current state-of-the-art crystalline multijunction solar cells are 30 % efficient with the cost of 30 to 40 /Wp. Increasing conversion efficiency of > 30% will enable to reduce the cost < $1/Wp and useful for various power platforms supporting mobile wireless, laptop, tent applications. Solar cell comprises with three dimensional blocks are shown to be higher conversion-efficiency than standard flat-type solar cell. Incorporating nano-scaled blocks in solar cell structures are shown to be increased performances due to (i) increase of the surface area to volume ratio, (ii) brining the junction closer to the carrier generation region which eliminate the carrier recombination , (iii) absorption of all incident photon flux, and (iv) broadening the absorption spectrum. Our activities on next generation high performance solar cells based on micro-nano scaled structures and various material systems will be presented. Details fabrication process of micro-nano scaled solar cell friendly to mass scale manufacturing will be also be described. We have achieved more than 20x optical performance enhancement for the solar cell based on micro-scaled structures, than that of flat-type (standard) solar cell, fabricated on the same Si substrate and same process. Simulation results showed that significant improvement in conversion efficiency more than 30% is possible for even c-Si solar cell based on the micro-nano scaled structures. Key issues and challenges for bringing it to the manufacturing will be discussed.

  2. Summary of solar activity observed in the Mauna Loa Solar Observatory, 1980 - 1983

    NASA Astrophysics Data System (ADS)

    Rock, K.; Fisher, R.; Garcia, C.; Yasukawa, E.

    1983-11-01

    The following technical note summarizes solar activity observed during the first four years operation of the experiment systems of the Coronal Dynamics Project, which are located at the Mauna Loa Solar Observatory. This short report has been produced with the general aim of providing users of Mauna Loa observations with a summary of data for specific events. So that this table might be as useful as possible, a comprehensive review of three sources was performed. The plain language logs, identified as the so-called observer's logs, the now-discontinued activity logs, and the prominence monitor quality control logs were the sources from which the information in the following tables was obtained.

  3. High-Precision Measurements of the Solar Diameter and Oblateness by the Solar Disk Sextant (SDS) Experiment

    NASA Astrophysics Data System (ADS)

    Egidi, A.; Caccin, B.; Sofia, S.; Heaps, W.; Hoegy, W.; Twigg, L.

    2006-05-01

    We reduce and analyze, in a uniform way, all of the data obtained by the Solar Disk Sextant (SDS) experiment, concerning high-precision measurements of the solar radius and oblateness, in the bandwidth 590 {-} 670 nm, made onboard stratospheric balloons during a series of flights carried out in 1992, 1994, 1995, and 1996. The measured radius value appears anti-correlated with the level of solar activity, ranging from about 959.5 to 959.7 arcsec. Its variation from year to year is outside the error range, which is mostly due to a systematic diurnal behavior, particularly evident in the 1996 flight. The oblateness shows an analogous temporal behavior, ranging from about (4.3 to 10.3) × 10-6.

  4. High performance solar heating in the Rockies

    SciTech Connect

    Lichtwardt, M.

    2000-04-01

    Many industrial and commercial buildings require large amounts of ventilation air to maintain adequate indoor air quality and--as facility managers know--heating all that fresh air can be expensive. An innovative solar air heating technology offers an elegantly simple and cost-effective solution to the problem of heating makeup air, and helps protect the environment in the bargain by avoiding the release of greenhouse gases and other pollutants.

  5. High efficiency silicon solar cell review

    NASA Technical Reports Server (NTRS)

    Godlewski, M. P. (Editor)

    1975-01-01

    An overview is presented of the current research and development efforts to improve the performance of the silicon solar cell. The 24 papers presented reviewed experimental and analytic modeling work which emphasizes the improvment of conversion efficiency and the reduction of manufacturing costs. A summary is given of the round-table discussion, in which the near- and far-term directions of future efficiency improvements were discussed.

  6. High efficiency indium oxide/cadmium telluride solar cells

    NASA Astrophysics Data System (ADS)

    Nakazawa, T.; Takamizawa, K.; Ito, K.

    1987-02-01

    Solar cells have been fabricated by reactive deposition of thin-film n-In2O3 onto single-crystal p-CdTe. The cell has a total area solar power conversion efficiency of 13.4 percent which corresponds to an active area efficiency of 14.4 percent at air mass 1.5 without antireflection coatings. The cell consists of a buried homojunction structure with low dark saturation current density.

  7. A high resolution history of the El Niño - Southern Oscillation and of the solar activity during the Late Glacial - Early Holocene in the subtropical Andean region.

    NASA Astrophysics Data System (ADS)

    Giralt, S.; Schimmel, M.; Hernández, A.; Bao, R.; Valero-Garcés, B. L.; Sáez, A.; Pueyo, J. J.

    2009-04-01

    High-resolution laminated lacustrine sediments are excellent archives of the past hydrological changes and they provide valuable insights about the climatic processes that trigger these changes. The paleoclimatic records located in the Southern Hemisphere are fundamental for understanding the evolution of the El Niño - Southern Oscillation (ENSO) since this climatic phenomena is the main cause of droughts and floods in many areas of South America and other regions of the world, like Spain and Egypt. Available regional paleoclimate reconstructions show that modern climatic patterns in South America were established during the Late Holocene. The laminated sediments of Lago Chungará (18° 15' S - 69° 10' W, 4520 m a.s.l., Chilean altiplano) have allowed us to characterize the evolution of this climatic phenomena for the transition Late Glacial - Early Holocene (12,300 - 9,500 calendar years BP) as well as its relationship with other climate forcings, namely the solar activity. The studied sediments correspond to the lowermost 2.4 m of 8 m long Kullemberg cores recovered from this lake. These sediments are mainly made up of greenish and whitish laminae and thin layers constituted by diatomaceous oozes with carbonates and organic matter, arranged in rhythms and cycles. X-ray fluorescence (XRF) (Al, Si, S, K, Ca, Ti, Mn, Fe, Rb, Sr, Zn, Sb and Ba) analyses, total organic carbon (TOC), total carbon (TC), x-ray diffraction (XRD), biogenic silica, stable isotopes (delta18O and delta13C) on carbonates and on diatoms (delta18O) and magnetic susceptibility were determined in order to characterize the sediments of Lago Chungará. Previous statistical studies (cluster and Principal Component Analyses (PCA)) were used to disentangle the paleoclimatic signal from the other ones (volcanic and tectonic). The chronological model framework was built using 6 radiocarbon dates, allowing us to establish that laminated couplets were deposited on a pluriannual basis. These couplets are

  8. Facile preparation of black Nb4+ self-doped K4Nb6O17 microspheres with high solar absorption and enhanced photocatalytic activity.

    PubMed

    Zhou, Chao; Zhao, Yufei; Shang, Lu; Cao, Yinhu; Wu, Li-Zhu; Tung, Chen-Ho; Zhang, Tierui

    2014-08-28

    Black Nb(4+) self-doped K4Nb6O17 microspheres were prepared for the first time through a facile UV light photoreduction method. By the introduction of Nb(4+), the defective K4Nb6O17 can harvest the full spectrum of visible light as well as near-infrared light. The black K4Nb6O17 microspheres showed improved visible-light-driven photocatalytic H2 production activity. Importantly, the present synthetic approach is also applicable to the preparation of other Nb(4+) self-doped niobates. PMID:25011611

  9. Effects of Solar Activity Variation on the Low Latitude Topside Nighttime Ionosphere

    NASA Astrophysics Data System (ADS)

    Min, K. W.; Kim, H.; Park, J.; Park, S.; Lee, J.; Lee, E.

    2006-05-01

    We investigate the effects of solar activity variation on the topside nighttime ionosphere of the low latitude region using the DMSP F15 data taken at 840 km altitude as well as the KOMPSAT-1 data taken at 685 km altitude. The change of the ionospheric parameters shows a good correlation with F 10.7 variations, in accordance with 27-day solar rotations. The correlation is especially good when a time delay of 1 to 2 days is incorporated and when the F 10.7 variation is large. Vertical drift velocities and the oxygen ion fractions, observed by DMSP F15, are also seen to have good correlations with F 10.7 with similar time delays. We suspect the delayed correlation of the ionospheric response is closely related to the neutral density changes affected by the solar activity as it has been reported that changes in the solar soft X-rays and the neutral density are well correlated with a delay of approximately 1.5 days. We also compare the ionospheric response for the solar maximum period with that of the declining phase using the data for the period 2000 through 2004 during which average F 10.7 varied from over 200 to around 100. The density does not seem to saturate at high F 10.7 values even during the solar maximum phase, in contrast to the daytime ionospheric response reported previously. The density during the low solar activity cycle is observed to be lower than that of the high solar activity for the same F 10.7 values, implying the long term dependence of the ionosphere in addition to the prompt response of 1 to 2 days.

  10. Active region plasma outflows as sources of slow/intermediate solar wind

    NASA Astrophysics Data System (ADS)

    van Driel-Gesztelyi, Lidia M.

    2015-08-01

    L. van Driel-Gesztelyi (1,2,3), D. Baker (1), P. Démoulin (2), Culhane, J.L. (1), M.L. DeRosa (4) C.H. Mandrini (5,6), D.H. Brooks (7), A.N. Fazakerley (1), L.K. Harra (1), L. Zhao (7), T.H. Zurbuchen (7), F.A. Nuevo (5,6), A.M. Vásquez (5,6), G.D. Cristiani (5,6) M. Pick (2)1) UCL/MSSL, UK, (2) Paris Observatory, LESIA, CNRS, France, (3) Konkoly Observatory, Hungary, (4) Lockheed Martin Solar and Astrophysics Laboratory, USA, (5) IAFE, CONICET-UBA, Argentina (6) FCEN, UBA, Argentina (7) Dept. of Atmospheric, Oceanic and Earth Sciences, Univ. of Michigan, USAWe analyse plasma upflows of tens of km/s from the edges of solar active regions discovered by Hinode/EIS and investigate whether or not they become outflows, i.e. find their way into the solar wind. We analyse two magnetic configurations: bipolar and quadrupolar and find that the active region plasma may be directly channeled into the solar wind via interchange reconnection at a high-altitude null point above the active region especially when active regions are located besides coronal holes or in a more complex way via multiple reconnections even from under a closed helmet streamer. We relate the solar observations to in-situ slow/intermediate solar wind streams.

  11. High solar cycle spectral variations inconsistent with stratospheric ozone observations

    NASA Astrophysics Data System (ADS)

    Ball, W. T.; Haigh, J. D.; Rozanov, E. V.; Kuchar, A.; Sukhodolov, T.; Tummon, F.; Shapiro, A. V.; Schmutz, W.

    2016-03-01

    Solar variability can influence surface climate, for example by affecting the mid-to-high-latitude surface pressure gradient associated with the North Atlantic Oscillation. One key mechanism behind such an influence is the absorption of solar ultraviolet (UV) radiation by ozone in the tropical stratosphere, a process that modifies temperature and wind patterns and hence wave propagation and atmospheric circulation. The amplitude of UV variability is uncertain, yet it directly affects the magnitude of the climate response: observations from the SOlar Radiation and Climate Experiment (SORCE) satellite show broadband changes up to three times larger than previous measurements. Here we present estimates of the stratospheric ozone variability during the solar cycle. Specifically, we estimate the photolytic response of stratospheric ozone to changes in spectral solar irradiance by calculating the difference between a reference chemistry-climate model simulation of ozone variability driven only by transport (with no changes in solar irradiance) and observations of ozone concentrations. Subtracting the reference from simulations with time-varying irradiance, we can evaluate different data sets of measured and modelled spectral irradiance. We find that at altitudes above pressure levels of 5 hPa, the ozone response to solar variability simulated using the SORCE spectral solar irradiance data are inconsistent with the observations.

  12. More Solar Activities for Astro 101

    NASA Astrophysics Data System (ADS)

    West, M. L.

    2002-12-01

    For many astronomy students the sun is not only the brightest astronomical object they can observe but also the most interesting since it has an immediate effect on their daily lives. Students enjoy analyzing their own observations using a Sunspotter, or images from archives such as the RBSE CD-ROM (1999, 2000, T. Rector), or current images found on the Internet. They can measure each sunspot's latitude, longitude, and approximate surface area by transparent Stonyhurst grids and fine graph paper, or NIH Image or Scion Image tools. Graphing latitude vs. time shows its near constancy. Longitude increases linearly with time and allows a measure of the sun's rotation period. Area vs. time increases for some spot groups, decreases for others, and fades but revives for others. This behavior elicits a lot of questions, hypotheses, and plans for more observations. The variation of solar rotation period with latitude can be tested. Does the sun's rotation period change with month and year also? One of the oldest calendar markers is the sun's altitude at local noon. It can be measured easily with a paper scale attached to the cradle of a Sunspotter. Noticing the civil time at local noon allows one to understand the analemma. What do sunspots correlate with? Students have investigated the correlation of sunspot numbers or areas with radio bursts, visible light or x-ray flares, solar wind speed, density, or magnetic field, aurorae, geomagnetic storms, the Earth's ozone layer, aircraft flight safety, ultraviolet light, global average temperature, local daily temperature variations, power grid outages, disruptions of Earth orbiting satellites or interplanetary spacecraft, earthquakes, hurricanes, tornadoes, or other natural disasters,

  13. High-resolution microwave spectra of solar bursts

    NASA Technical Reports Server (NTRS)

    Stahli, M.; Gary, D. E.; Hurford, G. J.

    1989-01-01

    A phenomenological and statistical study of flares observed in total power with the frequency-agile interferometer at the Owens Valley Radio Observatory during several months of high solar activity in 1981 is reported. Roughly 80 percent of the events have a complex spectrum consisting of more than one spectral component, implying that the microwave radiation of a burst usually does not come from a single homogeneous source. The presence of more than one component can lead to significant errors when data with low spectral resolution are used to determine the low-side spectral index. The low-frequency slope of a single spectra component is often steeper than expected, and the peak frequency stays nearly constant throughout a microwave event.

  14. Multi-scale statistical analysis of coronal solar activity

    DOE PAGESBeta

    Gamborino, Diana; del-Castillo-Negrete, Diego; Martinell, Julio J.

    2016-07-08

    Multi-filter images from the solar corona are used to obtain temperature maps that are analyzed using techniques based on proper orthogonal decomposition (POD) in order to extract dynamical and structural information at various scales. Exploring active regions before and after a solar flare and comparing them with quiet regions, we show that the multi-scale behavior presents distinct statistical properties for each case that can be used to characterize the level of activity in a region. Information about the nature of heat transport is also to be extracted from the analysis.

  15. Variation of Meteor Heights and Solar-Cycle Activity

    NASA Astrophysics Data System (ADS)

    Porubcan, Vladimír; Bucek, Marek; Cevolani, Giordano; Zigo, Pavel

    2012-08-01

    Photographic meteor observations of the Perseid meteoroid stream compiled from the IAU Meteor Data Center catalogue are analyzed from the viewpoint of possible long-term variation of meteor heights with the solar-cycle activity, which was previously reported from radio observations. The observed beginning and end-point heights of the Perseids, normalized for the geocentric velocity and the absolute photographic magnitude, do not show a variation consistent with the solar-cycle activity. This result is valid for the mass range of larger meteoroids observed by photographic techniques, and must be still verified also for the range of smaller meteoroids observed by TV and radio methods.

  16. Multi-scale statistical analysis of coronal solar activity

    NASA Astrophysics Data System (ADS)

    Gamborino, Diana; del-Castillo-Negrete, Diego; Martinell, Julio J.

    2016-07-01

    Multi-filter images from the solar corona are used to obtain temperature maps that are analyzed using techniques based on proper orthogonal decomposition (POD) in order to extract dynamical and structural information at various scales. Exploring active regions before and after a solar flare and comparing them with quiet regions, we show that the multi-scale behavior presents distinct statistical properties for each case that can be used to characterize the level of activity in a region. Information about the nature of heat transport is also to be extracted from the analysis.

  17. Solar activity forecast: Spectral analysis and neurofuzzy prediction

    NASA Astrophysics Data System (ADS)

    Gholipour, Ali; Lucas, Caro; Araabi, Babak N.; Shafiee, Masoud

    2005-04-01

    Active research in the last two decades indicates that the physical precursor and solar dynamo techniques are preferred as practical tools for long-term prediction of solar activity. But why should we omit more than 23 cycles of solar activity history, and just use empirical methods or simple autoregressive methods on the basis of observations for the latest eight cycles? In this article, a method based on spectral analysis and neurofuzzy modeling is proposed that is capable of issuing very accurate long-term prediction of sunspot number time series. A locally linear neurofuzzy model is optimized for each of the principal components obtained from singular spectrum analysis, and the multi-step predicted values are recombined to make the sunspot number time series. The proposed method is used for solar cycles 22 and 23 and the results are remarkably good in comparison to the predictions made by solar dynamo and precursor methods. An early prediction of the maximum smoothed international sunspot number for cycle 24 is 145 in 2011 2012.

  18. Active control of the Chinese Giant Solar Telescope

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. NASA's New High Intensity Solar Environment Test Capability

    NASA Technical Reports Server (NTRS)

    Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H.

    2012-01-01

    Across the world, new spaceflight missions are being designed and executed that will place spacecraft and instruments into challenging environments throughout the solar system. To aid in the successful completion of these new missions, NASA has developed a new flexible space environment test platform. The High Intensity Solar Environment Test (HISET) capability located at NASA fs Marshall Space Flight Center provides scientists and engineers with the means to test spacecraft materials and systems in a wide range of solar wind and solar photon environments. Featuring a solar simulator capable of delivering approximately 1 MW/m2 of broad spectrum radiation at maximum power, HISET provides a means to test systems or components that could explore the solar corona. The solar simulator consists of three high-power Xenon arc lamps that can be operated independently over a range of power to meet test requirements; i.e., the lamp power can be greatly reduced to simulate the solar intensity at several AU. Integral to the HISET capability are charged particle sources that can provide a solar wind (electron and proton) environment. Used individually or in combination, the charged particle sources can provide fluxes ranging from a few nA/cm2 to 100s of nA/cm2 over an energy range of 50 eV to 100 keV for electrons and 100 eV to 30 keV for protons. Anchored by a high vacuum facility equipped with a liquid nitrogen cold shroud for radiative cooling scenarios, HISET is able to accommodate samples as large as 1 meter in diameter. In this poster, details of the HISET capability will be presented, including the wide ]ranging configurability of the system.

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

    NASA Astrophysics Data System (ADS)

    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

  2. Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

    SciTech Connect

    Stechel, Ellen Beth; Ambrosini, Andrea; Hall, Aaron Christopher; Lambert, Timothy L.; Staiger, Chad Lynn; Bencomo, Marlene

    2010-09-01

    Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications.

  3. Surface Texturing Investigated for a High Solar Absorptance Low Infrared Emittance Solar Collector

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.

    2001-01-01

    The objective of this work was to design, build, and vacuum test a high solar absorptance, low infrared emittance solar collector for heat engine and thermal switching applications. Mini-satellites proposed by the Applied Physics Laboratory for operation in environments that are subject to radiation threat may utilize a heat engine for power and a thermal bus for thermal control. To achieve this goal, a surface having high solar absorptance and low infrared emittance is needed. At the NASA Glenn Research Center, one concept being pursued to achieve this goal is texturing high thermal conductivity graphite epoxy composites using a directed atomic oxygen beam and then coating the textured surface with a reflective metallic coating. Coupons were successfully textured, coated, and evaluated. A variety of texturing conditions were explored, and textures were documented by scanning electron microscopy. Copper, gold, silver, iridium, and aluminum coatings were applied, and the highest solar absorptance to infrared emittance ratio was found to be 1.3. A full-sized solar collector was manufactured with this ratio, and the amount of heat collected was observed using an Inconel calorimeter installed in a bench-top vacuum chamber equipped with a solar simulator. Results to date indicate good heat flow through the system, with 9 W of heat flow measured by the calorimeter.

  4. SOLAR CYCLE VARIATIONS OF THE OCCURRENCE OF CORONAL TYPE III RADIO BURSTS AND A NEW SOLAR ACTIVITY INDEX

    SciTech Connect

    Lobzin, Vasili; Cairns, Iver H.; Robinson, Peter A.

    2011-07-20

    This Letter presents the results of studies of solar cycle variations of the occurrence rate of coronal type III radio bursts. The radio spectra are provided by the Learmonth Solar Radio Observatory (Western Australia), part of the USAF Radio Solar Telescope Network (RSTN). It is found that the occurrence rate of type III bursts strongly correlates with solar activity. However, the profiles for the smoothed type III burst occurrence rate differ considerably from those for the sunspot number, 10.7 cm solar radio flux, and solar flare index. The type III burst occurrence rate (T3BOR) is proposed as a new index of solar activity. T3BOR provides complementary information about solar activity and should be useful in different studies including solar cycle predictions and searches for different periodicities in solar activity. This index can be estimated from daily results of the Automated Radio Burst Identification System. Access to data from other RSTN sites will allow processing 24 hr radio spectra in near-real time and estimating true daily values of this index. It is also shown that coronal type III bursts can even occur when there are no visible sunspots on the Sun. However, no evidence is found that the bursts are not associated with active regions. It is also concluded that the type III burst productivity of active regions exhibits solar cycle variations.

  5. Magnetic Cloud Polarity and Geomagnetic Activities over Three Solar Cycles

    NASA Astrophysics Data System (ADS)

    Li, Y.; Luhmann, J.

    2006-12-01

    Interplanetary coronal mass ejections (ICMEs) that show fluxrope magnetic structures are named magnetic clouds (MCs). Majority of the MCs exhibit bipolar signature in their north-south component (Bz) in IMF measurements. The Bz component of a bipolar cloud is either NS (north first then turning south as the MC traverses the spacecraft) or SN. Studies show that the occurrence of these two types of MCs has some solar cycle dependence. However it appears to be a complex relationship as the switch between the two types of MCs is not concurrent with either the solar polar reversal or the time of the sunspot minimum when the new cycle sunspots start to appear. In this paper, we use ACE solar wind and IMF observations to obtain the most updated MC signatures and their temporal variation. In combination with our previously published results, we analyze MC polarity variations over the three solar cycles of 21, 22 and 23. Interpretations in terms of their solar sources will be attempted. On the other hand, the geomagnetic activities over the same solar cycles will be studied using geomagnetic indices. The geoeffectiveness of the MC will be evaluated in the aid of Dst indices.

  6. High Voltage Solar Concentrator Experiment with Implications for Future Space Missions

    NASA Technical Reports Server (NTRS)

    Mehdi, Ishaque S.; George, Patrick J.; O'Neill, Mark; Matson, Robert; Brockschmidt, Arthur

    2004-01-01

    This paper describes the design, development, fabrication, and test of a high performance, high voltage solar concentrator array. This assembly is believed to be the first ever terrestrial triple-junction-cell solar array rated at over 1 kW. The concentrator provides over 200 W/square meter power output at a nominal 600 Vdc while operating under terrestrial sunlight. Space-quality materials and fabrication techniques were used for the array, and the 3005 meter elevation installation below the Tropic of Cancer allowed testing as close as possible to space deployment without an actual launch. The array includes two concentrator modules, each with a 3 square meter aperture area. Each concentrator module uses a linear Fresnel lens to focus sunlight onto a photovoltaic receiver that uses 240 series-connected triple-junction solar cells. Operation of the two receivers in series can provide 1200 Vdc which would be adequate for the 'direct drive' of some ion engines or microwave transmitters in space. Lens aperture width is 84 cm and the cell active width is 3.2 cm, corresponding to a geometric concentration ratio of 26X. The evaluation includes the concentrator modules, the solar cells, and the materials and techniques used to attach the solar cells to the receiver heat sink. For terrestrial applications, a finned aluminum extrusion was used for the heat sink for the solar cells, maintaining a low cell temperature so that solar cell efficiency remains high.

  7. High temperature solar energy absorbing surfaces

    DOEpatents

    Schreyer, J.M.; Schmitt, C.R.; Abbatiello, L.A.

    A solar collector having an improved coating is provided. The coating is a plasma-sprayed coating comprising a material having a melting point above 500/sup 0/C at which it is stable and selected from the group of boron carbide, boron nitride, metals and metal oxides, nitrides, carbides, borides, and silicates. The coatings preferably have a porosity of about 15 to 25% and a thickness of less than 200 micrometers. The coatings can be provided by plasma-spraying particles having a mean diameter of about 10 to 200 micrometers.

  8. Highly Efficient Perovskite Solar Cells with Tunable Structural Color

    PubMed Central

    2015-01-01

    The performance of perovskite solar cells has been progressing over the past few years and efficiency is likely to continue to increase. However, a negative aspect for the integration of perovskite solar cells in the built environment is that the color gamut available in these materials is very limited and does not cover the green-to-blue region of the visible spectrum, which has been a big selling point for organic photovoltaics. Here, we integrate a porous photonic crystal (PC) scaffold within the photoactive layer of an opaque perovskite solar cell following a bottom-up approach employing inexpensive and scalable liquid processing techniques. The photovoltaic devices presented herein show high efficiency with tunable color across the visible spectrum. This now imbues the perovskite solar cells with highly desirable properties for cladding in the built environment and encourages design of sustainable colorful buildings and iridescent electric vehicles as future power generation sources. PMID:25650872

  9. Highly efficient perovskite solar cells with tunable structural color.

    PubMed

    Zhang, Wei; Anaya, Miguel; Lozano, Gabriel; Calvo, Mauricio E; Johnston, Michael B; Míguez, Hernán; Snaith, Henry J

    2015-03-11

    The performance of perovskite solar cells has been progressing over the past few years and efficiency is likely to continue to increase. However, a negative aspect for the integration of perovskite solar cells in the built environment is that the color gamut available in these materials is very limited and does not cover the green-to-blue region of the visible spectrum, which has been a big selling point for organic photovoltaics. Here, we integrate a porous photonic crystal (PC) scaffold within the photoactive layer of an opaque perovskite solar cell following a bottom-up approach employing inexpensive and scalable liquid processing techniques. The photovoltaic devices presented herein show high efficiency with tunable color across the visible spectrum. This now imbues the perovskite solar cells with highly desirable properties for cladding in the built environment and encourages design of sustainable colorful buildings and iridescent electric vehicles as future power generation sources. PMID:25650872

  10. Long-Range Solar Activity Predictions: A Reprieve from Cycle #24's Activity

    NASA Technical Reports Server (NTRS)

    Richon, K.; Schatten, K.

    2003-01-01

    We discuss the field of long-range solar activity predictions and provide an outlook into future solar activity. Orbital predictions for satellites in Low Earth Orbit (LEO) depend strongly on exospheric densities. Solar activity forecasting is important in this regard, as the solar ultra-violet (UV) and extreme ultraviolet (EUV) radiations inflate the upper atmospheric layers of the Earth, forming the exosphere in which satellites orbit. Rather than concentrate on statistical, or numerical methods, we utilize a class of techniques (precursor methods) which is founded in physical theory. The geomagnetic precursor method was originally developed by the Russian geophysicist, Ohl, using geomagnetic observations to predict future solar activity. It was later extended to solar observations, and placed within the context of physical theory, namely the workings of the Sun s Babcock dynamo. We later expanded the prediction methods with a SOlar Dynamo Amplitude (SODA) index. The SODA index is a measure of the buried solar magnetic flux, using toroidal and poloidal field components. It allows one to predict future solar activity during any phase of the solar cycle, whereas previously, one was restricted to making predictions only at solar minimum. We are encouraged that solar cycle #23's behavior fell closely along our predicted curve, peaking near 192, comparable to the Schatten, Myers and Sofia (1996) forecast of 182+/-30. Cycle #23 extends from 1996 through approximately 2006 or 2007, with cycle #24 starting thereafter. We discuss the current forecast of solar cycle #24, (2006-2016), with a predicted smoothed F10.7 radio flux of 142+/-28 (1-sigma errors). This, we believe, represents a reprieve, in terms of reduced fuel costs, etc., for new satellites to be launched or old satellites (requiring reboosting) which have been placed in LEO. By monitoring the Sun s most deeply rooted magnetic fields; long-range solar activity can be predicted. Although a degree of uncertainty

  11. GLOBAL DYNAMICS OF SUBSURFACE SOLAR ACTIVE REGIONS

    SciTech Connect

    Jouve, L.; Brun, A. S.

    2013-01-01

    We present three-dimensional numerical simulations of a magnetic loop evolving in either a convectively stable or unstable rotating shell. The magnetic loop is introduced into the shell in such a way that it is buoyant only in a certain portion in longitude, thus creating an {Omega}-loop. Due to the action of magnetic buoyancy, the loop rises and develops asymmetries between its leading and following legs, creating emerging bipolar regions whose characteristics are similar to those of observed spots at the solar surface. In particular, we self-consistently reproduce the creation of tongues around the spot polarities, which can be strongly affected by convection. We further emphasize the presence of ring-shaped magnetic structures around our simulated emerging regions, which we call 'magnetic necklace' and which were seen in a number of observations without being reported as of today. We show that those necklaces are markers of vorticity generation at the periphery and below the rising magnetic loop. We also find that the asymmetry between the two legs of the loop is crucially dependent on the initial magnetic field strength. The tilt angle of the emerging regions is also studied in the stable and unstable cases and seems to be affected both by the convective motions and the presence of a differential rotation in the convective cases.

  12. Improved High/Low Junction Silicon Solar Cell

    NASA Technical Reports Server (NTRS)

    Neugroschel, A.; Pao, S. C.; Lindholm, F. A.; Fossum, J. G.

    1986-01-01

    Method developed to raise value of open-circuit voltage in silicon solar cells by incorporating high/low junction in cell emitter. Power-conversion efficiency of low-resistivity silicon solar cell considerably less than maximum theoretical value mainly because open-circuit voltage is smaller than simple p/n junction theory predicts. With this method, air-mass-zero opencircuit voltage increased from 600 mV level to approximately 650 mV.

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

    NASA Astrophysics Data System (ADS)

    Kitchatinov, L. L.; Olemskoy, S. V.

    2016-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Kitchatinov, L. L.; Olemskoy, S. V.

    2016-04-01

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

  15. The Progress of Solar Cycle 24 at High Latitudes

    NASA Astrophysics Data System (ADS)

    Altrock, R. C.

    2010-06-01

    The "extended" solar cycle 24 began in 1999 near 70° latitude, similarly to cycle 23 in 1989 and cycle 22 in 1979. The extended cycle is manifested by persistent Fe XIV coronal emission appearing near 70° latitude and slowly migrating towards the equator, merging with the latitudes of sunspots and active regions (the "butterfly diagram") after several years. Cycle 24 began its migration at a rate 40% slower than the previous two solar cycles, thus indicating the possibility of a peculiar cycle. However, the onset of the "Rush to the Poles" of polar crown prominences and their associated coronal emission, which has been a precursor to solar maximum in recent cycles (cf. Altrock 2003), has just been identified in the northern hemisphere. Peculiarly, this "rush" is leisurely, at only 50% of the rate in the previous two cycles. The properties of the current "Rush to the Poles" yields an estimate of 2013 or 2014 for solar maximum.

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

    NASA Astrophysics Data System (ADS)

    Zuccarello, Francesca; Balmaceda, Laura; Cessateur, Gael; Cremades, Hebe; Guglielmino, Salvatore L.; Lilensten, Jean; Dudok de Wit, Thierry; Kretzschmar, Matthieu; Lopez, Fernando M.; Mierla, Marilena; Parenti, Susanna; Pomoell, Jens; Romano, Paolo; Rodriguez, Luciano; Srivastava, Nandita; Vainio, Rami; West, Matt; Zuccarello, Francesco P.

    2013-04-01

    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.

  17. Flexible, highly efficient all-polymer solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Taesu; Kim, Jae-Han; Kang, Tae Eui; Lee, Changyeon; Kang, Hyunbum; Shin, Minkwan; Wang, Cheng; Ma, Biwu; Jeong, Unyong; Kim, Taek-Soo; Kim, Bumjoon J.

    2015-10-01

    All-polymer solar cells have shown great potential as flexible and portable power generators. These devices should offer good mechanical endurance with high power-conversion efficiency for viability in commercial applications. In this work, we develop highly efficient and mechanically robust all-polymer solar cells that are based on the PBDTTTPD polymer donor and the P(NDI2HD-T) polymer acceptor. These systems exhibit high power-conversion efficiency of 6.64%. Also, the proposed all-polymer solar cells have even better performance than the control polymer-fullerene devices with phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor (6.12%). More importantly, our all-polymer solar cells exhibit dramatically enhanced strength and flexibility compared with polymer/PCBM devices, with 60- and 470-fold improvements in elongation at break and toughness, respectively. The superior mechanical properties of all-polymer solar cells afford greater tolerance to severe deformations than conventional polymer-fullerene solar cells, making them much better candidates for applications in flexible and portable devices.

  18. Flexible, highly efficient all-polymer solar cells

    PubMed Central

    Kim, Taesu; Kim, Jae-Han; Kang, Tae Eui; Lee, Changyeon; Kang, Hyunbum; Shin, Minkwan; Wang, Cheng; Ma, Biwu; Jeong, Unyong; Kim, Taek-Soo; Kim, Bumjoon J.

    2015-01-01

    All-polymer solar cells have shown great potential as flexible and portable power generators. These devices should offer good mechanical endurance with high power-conversion efficiency for viability in commercial applications. In this work, we develop highly efficient and mechanically robust all-polymer solar cells that are based on the PBDTTTPD polymer donor and the P(NDI2HD-T) polymer acceptor. These systems exhibit high power-conversion efficiency of 6.64%. Also, the proposed all-polymer solar cells have even better performance than the control polymer-fullerene devices with phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor (6.12%). More importantly, our all-polymer solar cells exhibit dramatically enhanced strength and flexibility compared with polymer/PCBM devices, with 60- and 470-fold improvements in elongation at break and toughness, respectively. The superior mechanical properties of all-polymer solar cells afford greater tolerance to severe deformations than conventional polymer-fullerene solar cells, making them much better candidates for applications in flexible and portable devices. PMID:26449658

  19. Active region upflow plasma: its relation to small activity and the solar wind

    NASA Astrophysics Data System (ADS)

    Mandrini, Cristina H.; Culhane, J. Leonard; Cristiani, Germán; Vásquez, Alberto; Van Driel-Gesztelyi, Lidia; Baker, Deborah; Pick, Monique; Demoulin, Pascal; Nuevo, Federico

    Recent studies show that active region (AR) upflowing plasma, observed by the Hinode EUV Imaging Spectrometer (EIS), can gain access to open field lines and be released into the solar wind via magnetic interchange reconnection occurring below the source surface at magnetic null-points in pseudo-streamer configurations. When only one simple bipolar AR is present on the Sun and it is fully covered by the separatrix of a streamer, like AR 10978 on December 2007, it seems unlikely that the upflowing AR plasma could find its way into the slow solar wind. However, signatures of plasma with AR composition at 1 AU that appears to originate from the West of AR 10978 were recently found by Culhane and coworkers. We present a detailed topology analysis of AR 10978 based on a linear force-free magnetic field model at the AR scale, combined with a global PFSS model. This allows us, on one hand, to explain the variations observed in the upflows to the West of the AR as the result of magnetic reconnection at quasi-separatrix layers (QSLs). While at a global scale, we show that reconnection, occurring in at least two main steps, first at QSLs and later at a high-altitude coronal null-point, allows the AR plasma to get around the topological obstacle of the streamer separatrix and be released into the solar wind.

  20. High temperature solar photon engines. [heat engines for terrestrial and space-based solar power plants

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.; Decher, R.; Mattick, A. T.; Lau, C. V.

    1978-01-01

    High temperature heat engines designed to make maximum use of the thermodynamic potential of concentrated solar radiation are described. Plasmas between 2000 K and 4000 K can be achieved by volumetric absorption of radiation in alkali metal vapors, leading to thermal efficiencies up to 75% for terrestrial solar power plants and up to 50% for space power plants. Two machines capable of expanding hot plasmas using practical technology are discussed. A binary Rankine cycle uses fluid mechanical energy transfer in a device known as the 'Comprex' or 'energy exchanger.' The second machine utilizes magnetohydrodynamics in a Brayton cycle for space applications. Absorption of solar energy and plasma radiation losses are investigated for a solar superheater using potassium vapor.

  1. A solar cycle timing predictor - The latitude of active regions

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth H.

    1990-01-01

    A 'Spoerer butterfly' method is used to examine solar cycle 22. It is shown from the latitude of active regions that the cycle can now be expected to peak near November 1989 + or - 8 months, basically near the latter half of 1989.

  2. No evidence for planetary influence on solar activity

    NASA Astrophysics Data System (ADS)

    Cameron, R. H.; Schüssler, M.

    2013-09-01

    Context. Recently, Abreu et al. (2012, A&A. 548, A88) proposed a long-term modulation of solar activity through tidal effects exerted by the planets. This claim is based upon a comparison of (pseudo-)periodicities derived from records of cosmogenic isotopes with those arising from planetary torques on an ellipsoidally deformed Sun. Aims: We examined the statistical significance of the reported similarity of the periods. Methods: The tests carried out by Abreu et al. were repeated with artificial records of solar activity in the form of white or red noise. The tests were corrected for errors in the noise definition as well as in the apodisation and filtering of the random series. Results: The corrected tests provide probabilities for chance coincidence that are higher than those claimed by Abreu et al. by about 3 and 8 orders of magnitude for white and red noise, respectively. For an unbiased choice of the width of the frequency bins used for the test (a constant multiple of the frequency resolution) the probabilities increase by another two orders of magnitude to 7.5% for red noise and 22% for white noise. Conclusions: The apparent agreement between the periodicities in records of cosmogenic isotopes as proxies for solar activity and planetary torques is statistically insignificant. There is no evidence for a planetary influence on solar activity.

  3. Analysis of Solar Magnetic Activity with the Wavelet Coherence Method

    NASA Astrophysics Data System (ADS)

    Velasco, V. M.; Perez-Peraza, J. A.; Mendoza, B. E.; Valdes-Galicia, J. F.; Sosa, O.; Alvarez-Madrigal, M.

    2007-05-01

    The origin, behavior and evolution of the solar magnetic field is one of the main challenges of observational and theoretical solar physics. Up to now the Dynamo theory gives us the best approach to the problem. However, it is not yet able to predict many features of the solar activity, which seems not to be strictly a periodical phenomenon. Among the indicators of solar magnetic variability there is the 11-years cycle of sunspots, as well as the solar magnetic cycle of 22 years (the Hale cycle). In order to provide more elements to the Dynamo theory that could help it in the predicting task, we analyze here the plausible existence of other periodicities associated with the solar magnetic field. In this preliminary work we use historical data (sunspots and aurora borealis), proxies (Be10 and C14) and modern instrumental data (Coronal Holes, Cosmic Rays, sunspots, flare indexes and solar radio flux at 10.7 cm). To find relationships between different time-frequency series we have employed the t Wavelet Coherence technique: this technique indicates if two time-series of solar activity have the same periodicities in a given time interval. If so, it determines whether such relation is a linear one or not. Such a powerful tool indicates that, if some periodicity at a given frequency has a confidence level below 95%, it appears very lessened or does not appear in the Wavelet Spectral Analysis, such periodicity does not exist . Our results show that the so called Glaisberg cycle of 80-90 years and the periodicity of 205 years (the Suess cycle) do not exist . It can be speculated that such fictitious periodicities hav been the result of using the Fourier transform with series with are not of stationary nature, as it is the case of the Be10 and C14 series. In contrast we confirm the presence of periodicities of 1.3, 1.7, 3.5, 5.5, 7, 60, 120 and 240 years. The concept of a Glaisberg cycle falls between those of 60 and 120 years. We conclude that the periodicity of 120 years

  4. The ionosphere under extremely prolonged low solar activity

    NASA Astrophysics Data System (ADS)

    Liu, Libo; Chen, Yiding; Le, Huijun; Kurkin, Vladimir I.; Polekh, Nelya M.; Lee, Chien-Chih

    2011-04-01

    A critical question in ionospheric physics is the state of the ionosphere and relevant processes under extreme solar activities. The solar activity during 2007-2009 is extremely prolonged low, which offers us a unique opportunity to explore this issue. In this study, we collected the global ionosonde measurements of the F2 layer critical frequency (foF2), E layer critical frequency (foE), and F layer virtual height (h‧F) and the total electron content (TEC) maps produced by the Jet Propulsion Laboratory, which were retrieved from dual-frequency GPS receivers distributed worldwide, to investigate the ionospheric phenomena during solar minimum of cycle 23/24, particularly the difference in the ionosphere between solar minima of cycle 23/24 and the preceding cycles. The analysis indicates that the moving 1 year mean foF2 at most ionosonde stations and the global average TEC went to the lowest during cycle 23/24 minimum. The solar cycle differences in foF2 minima display local time dependence, being more negative during the daytime than at night. Furthermore, the cycle difference in daytime foF2 minima is about -0.5 MHz and even reaches to around -1.2 MHz. In contrast, a complex picture presents in global h‧F and foE. Evident reduction exists prevailingly in the moving 1 year mean h‧F at most stations, while no huge differences are detected at several stations. A compelling feature is the increase in foE at some stations, which requires independent data for further validation. Quantitative analysis indicates that record low foF2 and low TEC can be explained principally in terms of the decline in solar extreme ultraviolet irradiance recorded by SOHO/SEM, which suggests low solar EUV being the prevailing contributor to the unusual low electron density in the ionosphere during cycle 23/24 minimum. It also verifies that a quadratic fitting still reasonably captures the solar variability of foF2 and global average TEC at such low solar activity levels.

  5. High-latitude geomagnetic disturbances during ascending solar cycle 24

    NASA Astrophysics Data System (ADS)

    Peitso, Pyry; Tanskanen, Eija; Stolle, Claudia; Berthou Lauritsen, Nynne; Matzka, Jürgen

    2015-04-01

    High-latitude regions are very convenient for study of several space weather phenomena such as substorms. Large geographic coverage as well as long time series of data are essential due to the global nature of space weather and the long duration of solar cycles. We will examine geomagnetic activity in Greenland from magnetic field measurements taken by DTU (Technical University of Denmark) magnetometers during the years 2010 to 2014. The study uses data from 13 magnetometer stations located on the east coast of Greenland and one located on the west coast. The original measurements are in one second resolution, thus the amount of data is quite large. Magnetic field H component (positive direction towards the magnetic north) was used throughout the study. Data processing will be described from calibration of original measurements to plotting of long time series. Calibration consists of determining the quiet hour of a given day and reducing the average of that hour from all the time steps of the day. This normalizes the measurements and allows for better comparison between different time steps. In addition to the full time line of measurements, daily, monthly and yearly averages will be provided for all stations. Differential calculations on the change of the H component will also be made available for the duration of the full data set. Envelope curve plots will be presented for duration of the time line. Geomagnetic conditions during winter and summer will be compared to examine seasonal variation. Finally the measured activity will be compared to NOAA (National Oceanic and Atmospheric Administration) issued geomagnetic space weather alerts from 2010 to 2014. Calculations and plotting of measurement data were done with MATLAB. M_map toolbox was used for plotting of maps featured in the study (http://www2.ocgy.ubc.ca/~rich/map.html). The study was conducted as a part of the ReSoLVE (Research on Solar Long-term Variability and Effects) Center of Excellence.

  6. Spectroscopic Observations of Fe XVIII in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Teriaca, Luca; Warren, Harry P.; Curdt, Werner

    2012-08-01

    The large uncertainties associated with measuring the amount of high temperature emission in solar active regions (ARs) represents a significant impediment to making progress on the coronal heating problem. Most current observations at temperatures of 3 MK and above are taken with broadband soft X-ray instruments. Such measurements have proven difficult to interpret unambiguously. Here, we present the first spectroscopic observations of the Fe XVIII 974.86 Å emission line in an on-disk AR taken with the SUMER instrument on SOHO. Fe XVIII has a peak formation temperature of 7.1 MK and provides important constraints on the amount of impulsive heating in the corona. Detailed evaluation of the spectra and comparison of the SUMER data with soft X-ray images from the X-Ray Telescope on Hinode confirm that this line is unblended. We also compare the spectroscopic data with observations from the Atmospheric Imaging Assembly (AIA) 94 Å channel on the Solar Dynamics Observatory. The AIA 94 Å channel also contains Fe XVIII, but is blended with emission formed at lower temperatures. We find that it is possible to remove the contaminating blends and form relatively pure Fe XVIII images that are consistent with the spectroscopic observations from SUMER. The observed spectra also contain the Ca XIV 943.63 Å line that, although a factor 2-6 weaker than the Fe XVIII 974.86 Å line, allows us to probe the plasma around 3.5 MK. The observed ratio between the two lines indicates (isothermal approximation) that most of the plasma in the brighter Fe XVIII AR loops is at temperatures between 3.5 and 4 MK.

  7. Multiscale comparative spectral analysis of satellite total solar irradiance measurements from 2003 to 2013 reveals a planetary modulation of solar activity and its nonlinear dependence on the 11 yr solar cycle

    NASA Astrophysics Data System (ADS)

    Scafetta, N.; Willson, R. C.

    2013-11-01

    Herein we adopt a multiscale dynamical spectral analysis technique to compare and study the dynamical evolution of the harmonic components of the overlapping ACRIMSAT/ACRIM3 (Active Cavity Radiometer Irradiance Monitor Satellite/Active Cavity Radiometer Irradiance Monitor 3), SOHO/VIRGO (Solar and Heliopheric Observatory/Variability of solar Irradiance and Gravity Oscillations), and SORCE/TIM (Solar Radiation and Climate Experiment/Total Irradiance Monitor) total solar irradiance (TSI) records during 2003.15 to 2013.16 in solar cycles 23 and 24. The three TSI time series present highly correlated patterns. Significant power spectral peaks are common to these records and are observed at the following periods: ~ 0.070 yr, ~ 0.097 yr, ~ 0.20 yr, ~ 0.25 yr, ~ 0.30-0.34 yr, and ~ 0.39 yr. Less certain spectral peaks occur at about 0.55 yr, 0.60-0.65 yr and 0.7-0.9 yr. Four main frequency periods at ~ 4.8 days (~ 0.068 yr), ~ 27.3 days (~ 0.075 yr), at ~ 34-35 days (~ 0.093-0.096 yr), and ~ 36-38 days (~ 0.099-0.104 yr) characterize the solar rotation cycle. The amplitude of these oscillations, in particular of those with periods larger than 0.5 yr, appears to be modulated by the ~ 11 yr solar cycle. Similar harmonics have been found in other solar indices. The observed periodicities are found highly coherent with the spring, orbital and synodic periods of Mercury, Venus, Earth and Jupiter. We conclude that solar activity is likely modulated by planetary gravitational and electromagnetic forces acting on the Sun. The strength of the Sun's response to planetary forcing depends nonlinearly on the state of internal solar dynamics; planetary-Sun coupling effects are enhanced during solar activity maxima and attenuated during minima.

  8. THE MAGNETIC ENERGY-HELICITY DIAGRAM OF SOLAR ACTIVE REGIONS

    SciTech Connect

    Tziotziou, Kostas; Georgoulis, Manolis K.; Raouafi, Nour-Eddine

    2012-11-01

    Using a recently proposed nonlinear force-free method designed for single-vector magnetograms of solar active regions, we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms corresponding to 42 different active regions. We find a statistically robust, monotonic correlation between the free magnetic energy and the relative magnetic helicity in the studied regions. This correlation implies that magnetic helicity, in addition to free magnetic energy, may be an essential ingredient for major solar eruptions. Eruptive active regions appear well segregated from non-eruptive ones in both free energy and relative helicity with major (at least M-class) flares occurring in active regions with free energy and relative helicity exceeding 4 Multiplication-Sign 10{sup 31} erg and 2 Multiplication-Sign 10{sup 42} Mx{sup 2}, respectively. The helicity threshold agrees well with estimates of the helicity contents of typical coronal mass ejections.

  9. An Alternative Measure of Solar Activity from Detailed Sunspot Datasets

    NASA Astrophysics Data System (ADS)

    Muraközy, J.; Baranyi, T.; Ludmány, A.

    2016-05-01

    The sunspot number is analyzed by using detailed sunspot data, including aspects of observability, sunspot sizes, and proper identification of sunspot groups as discrete entities of solar activity. The tests show that in addition to the subjective factors there are also objective causes of the ambiguities in the series of sunspot numbers. To introduce an alternative solar-activity measure, the physical meaning of the sunspot number has to be reconsidered. It contains two components whose numbers are governed by different physical mechanisms and this is one source of the ambiguity. This article suggests an activity index, which is the amount of emerged magnetic flux. The only long-term proxy measure is the detailed sunspot-area dataset with proper calibration to the magnetic flux. The Debrecen sunspot databases provide an appropriate source for the establishment of the suggested activity index.

  10. Correlation of Solar Activities with the Telluric Currents Level in the Northern Region of Malaysia

    NASA Astrophysics Data System (ADS)

    Razelan, Mazlina M.; Said, N. Masdiana Md; Aziz, A. H. A.; Chong, H. Y.; Nawawi, M.

    2010-07-01

    The relation between solar activities and the geomagnetic field induced currents (GIC) have been well studied in the auroral region and it usually occurs most frequently at high latitudes. However, during major geomagnetic storms, the auroral zone can extend substantially towards lower latitudes. Disturbance caused by solar activities can disrupt power grids and also increase the corrosion rate of buried natural gas pipelines. GIC are driven by the geomagnetic field induced by a geomagnetic disturbance. In this paper, we investigated the correlation between solar activities using the interplanetary magnetic field (IMF) and geomagnetic disturbance storm time (DST) index data with the telluric currents (also referred to as geomagnetic induced currents GIC) level through the disturbance pattern of geomagnetic field. The research areas are from Lunas in Kedah to Perlis. The pattern of geomagnetic field disturbance had been identified and analyzed to investigate the harmful effect of geomagnetic storms towards the performance of complex power grid in Malaysia.

  11. Predicted solar flare activity for the 1990s - Possible effects on navigation systems

    SciTech Connect

    Kunches, J.M.; Hirman, J.W. )

    1990-01-01

    The current solar cycle, which began in September 1986, may prove to be the highest ever, as measured by sunspot numbers and radio flux. The cycle's frequent and strong solar flare activity can be illustrated by the March 1989 episode, which caused many problems for navigation systems. Flares and the geomagnetic storms that sometimes accompany them can disrupt low-frequency systems such as Loran-C, as well as the satellite-borne GPS. Although the maximum of the solar cycle is expected during the first quarter of 1990, flare activity is likely to persist at high levels for a few years to follow. Geomagnetic activity may occur at any time in the cycle, and thus geomagnetic disruptions are possible at any point in the 1990s. 5 refs.

  12. Birthdates of patients affected by mental illness and solar activity: A study from Italy

    NASA Astrophysics Data System (ADS)

    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.

  13. Design concepts to improve high performance solar simulator

    NASA Technical Reports Server (NTRS)

    Juranek, H. J.; Frey, H. U.

    1986-01-01

    By improving several important components of the well known off-axis solar simulator system, a considerable step forward was made. The careful mathematical studies on the optics and the thermal side of the problem lead to a highly efficient system with low operational costs and a high reliability. The actual performance of the simulator is significantly better than the specified one, and the efficiency is outstanding. No more than 12 lamps operating at 18 kW are required to obtain one Solar Constant in the 6 m beam. It is now known that by using sophisticated optics, even larger facilities of high performance can be designed without leaving the proven off-axis concept and using a spherical mirror. Using high performance optics is a means of reducing costs at a given size of beam because the number of lamps is one of the most cost driving factors in the construction of a solar simulator.

  14. High Efficiency Solar Power via Separated Photo and Voltaic Pathways

    SciTech Connect

    Michael J. Naughton

    2009-02-17

    This project demonstrates a novel nanostructured solar cell architecture capable of achieving high efficiency levels that is relatively simple and inexpensive to manufacture. The high efficiency will be achieved by the novel structure that separates the path of the photons from the path of the generated charge carriers. In this way, the photon path can be long for maximum light absorption, while the path for carriers can be short for maximum electronic energy harvesting. The combination of maximum light absorption coupled with maximum carrier harvesting is the basis for the expected high efficiency. The project will develop high efficiency solar cell prototypes utilizing this unique nanostructured architecture. The project addresses the fundamental limitation inherent in all current solar cell designs, and which opens a pathway to development for high efficiency solar cells at low cost. Realizing this goal will result in a levelized cost of electricity in the range of 10¢/kWh, which would achieve the long-sought goal of making photovoltaic electricity cost competitive with fossil-fuel generated electricity without any governmental subsidies. This breakthrough would spur the already rapid growth in the photovoltaic industry to an explosive pace, with significant, widespread benefit to the national economy and the nation’s energy security. The initial target of the program is to develop single-junction solar cells using ultrathin amorphous silicon with the performance approaching that of single crystal silicon cells.

  15. Climate response to imposed solar radiation reductions in high latitudes

    NASA Astrophysics Data System (ADS)

    MacCracken, M. C.; Shin, H.-J.; Caldeira, K.; Ban-Weiss, G. A.

    2012-07-01

    Increasing concentrations of greenhouse gases are the primary contributor to the 0.8 °C increase in the global average temperature since the late 19th century, shortening cold seasons and lengthening warm seasons. The warming is amplified in polar regions, causing retreat of sea ice, snow cover, permafrost, mountain glaciers, and ice sheets, while also modifying mid-latitude weather, amplifying global sea level rise, and initiating high-latitude carbon feedbacks. Model simulations in which we reduced solar insolation over high latitudes not only cooled those regions, but also drew energy from lower latitudes, exerting a cooling influence over much of the hemisphere in which the reduction was imposed. Our simulations, which used the National Center for Atmospheric Research's CAM3.1 atmospheric model coupled to a slab ocean, indicated that, on a normalized basis, high-latitude reductions in absorbed solar radiation have a significantly larger cooling influence than equivalent solar reductions spread evenly over the Earth. This amplified influence occurred because high-latitude surface cooling preferentially increased sea ice fraction and, therefore, surface albedo, leading to a larger deficit in the radiation budget at the top of the atmosphere than from an equivalent global reduction in solar radiation. Reductions in incoming solar radiation in one polar region (either north or south) resulted in increased poleward energy transport during that hemisphere's cold season and shifted the Inter-Tropical Convergence Zone (ITCZ) away from that pole, whereas equivalent reductions in both polar regions tended to leave the ITCZ approximately in place. Together, these results suggest that, until emissions reductions are sufficient to limit the warming influence of greenhouse gas concentrations, polar reductions in solar radiation, if they can be efficiently and effectively implemented, might, because of fewer undesirable side effects than for global solar radiation reductions

  16. Cosmic rays, solar activity, magnetic coupling, and lightning incidence

    NASA Technical Reports Server (NTRS)

    Ely, J. T. A.

    1984-01-01

    A theoretical model is presented and described that unifies the complex influence of several factors on spatial and temporal variation of lightning incidence. These factors include the cosmic radiation, solar activity, and coupling between geomagnetic and interplanetary (solar wind) magnetic fields. Atmospheric electrical conductivity in the 10 km region was shown to be the crucial parameter altered by these factors. The theory reconciles several large scale studies of lightning incidence previously misinterpreted or considered contradictory. The model predicts additional strong effects on variations in lightning incidence, but only small effects on the morphology and rate of thunderstorm development.

  17. Highly Flexible Dye-sensitized Solar Cells Produced by Sewing Textile Electrodes on Cloth

    PubMed Central

    Yun, Min Ju; Cha, Seung I.; Seo, Seon Hee; Lee, Dong Y.

    2014-01-01

    Textile forms of solar cells possess special advantages over other types of solar cells, including their light weight, high flexibility, and mechanical robustness. Recent demand for wearable devices has promoted interest in the development of high-efficiency textile-based solar cells for energy suppliers. However, the weaving process occurs under high-friction, high-tension conditions that are not conducive to coated solar-cell active layers or electrodes deposited on the wire or strings. Therefore, a new approach is needed for the development of textile-based solar cells suitable for woven fabrics for wide-range application. In this report, we present a highly flexible, efficient DSSC, fabricated by sewing textile-structured electrodes onto casual fabrics such as cotton, silk, and felt, or paper, thereby forming core integrated DSSC structures with high energy-conversion efficiency (~5.8%). The fabricated textile-based DSSC devices showed high flexibility and high performance under 4-mm radius of curvature over thousands of deformation cycles. Considering the vast number of textile types, our textile-based DSSC devices offer a huge range of applications, including transparent, stretchable, wearable devices. PMID:24957920

  18. The variations of prominence activities during solar cycle

    NASA Astrophysics Data System (ADS)

    Shimojo, Masumi

    The prominence activities (prominence eruption/disappearance) in the solar atmosphere closely relate with the CMEs that cause great influences on heliosphere and magnetosphere. Gopal-swarmy et al. (2003) reported that 72 The Nobeyama Radioheliograph (NoRH) is observing Sun in microwave (17 GHz) since 1992. At a flare, the main component of the microwave from Sun is emitted from non-thermal electrons that are accelerated by flare. On the other hand, the main component of the microwave is thermal emission when Sun is quiet, and a prominence is clearly observed in microwave because there is the prominence on the limb. We developed the automatic prominence activity detection program based on 17 GHz images observed by NoRH, and investigated the variation of the properties of the prominence activities that oc-curred from 1992 to the end of 2009. We found the following results. 1. The variation in the number of prominence activities is similar to that of sunspots during one solar cycle but there are differences between the peak times of prominence activities and sunspots. 2. The frequency distribution as a function of the magnitude of the prominence activities the size of activated prominences at each phase shows a power-law distribution. The power-law index of the distribution does not change except around the solar minimum. 3. The number of promi-nence activities has a dependence on the latitude On the other hand the average magnitude is independent of the latitude. In the paper, we will also discuss the relationship the other properties of prominence eruptions, solar cycle and the photospheric magnetic field.

  19. High Efficiency InP Solar Cells Through Nanostructuring

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel; Murray, Joseph; Munday, Jeremy

    We describe high efficiency InP solar cells which utilize a periodic array of optically designed TiO2 nanocylinders. Optical and electronic simulations were performed to determine the spectrally resolved reflectivity and I-V characteristics of potential devices under AM1.5G illumination. The reflectivity of InP solar cells with these nanocylinders is found to have an average value of 2% over the visible and near-IR spectral range, which outperforms traditional antireflection coatings. Coupling between Mie scattering resonances and thin film interference effects is found to accurately describe the optical enhancement provided by the nanocylinders. These nanostructured solar cells have power conversion efficiencies greater than 23%, which is comparable to the highest quoted efficiencies for InP solar cells.

  20. CONDITIONED ANALYSIS OF HIGH-LATITUDE SOLAR WIND INTERMITTENCY

    SciTech Connect

    D'Amicis, R.; Consolini, G.; Bavassano, B.; Bruno, R.

    2012-08-10

    The solar wind is a turbulent medium displaying intermittency. Its intermittent features have been widely documented and studied, showing how the intermittent character is different in fast and slow wind. In this paper, a statistical conditioned analysis of the solar wind intermittency for a period of high-latitude fast solar wind is presented. In particular, the intermittent features are investigated as a function of the Alfvenic degree of fluctuations at a given scale. The results show that the main contribution to solar wind intermittency is due to non-Alfvenic structures, while Alfvenic increments are found to be characterized by a smaller level of intermittency than the previous ones. Furthermore, the lifetime statistics of Alfvenic periods are discussed in terms of a multiscale texture of randomly oriented flux tubes.

  1. Ulysses solar wind plasma observations at high latitudes

    SciTech Connect

    Riley, P.; Bame, S.J.; Barraclough, B.L.

    1996-10-01

    Ulysses reached its peak northerly heliolatitude of 80.2{degrees}N on July 31, 1995, and now is moving towards aphelion at 5.41 AU which it will reach in May, 1998. We summarize measurements from the solar wind plasma experiment, SWOOPS, emphasizing northern hemispheric observations but also providing southern and equatorial results for comparison. The solar wind momentum flux during Ulysses` fast pole-to- pole transit at solar minimum was significantly higher over the poles than at near-equatorial latitudes, suggesting a non-circular cross section for the heliosphere. Furthermore, modest asymmetries in the wind speed, density, and mass flux were observed between the two hemispheres during the fast latitude scan. The solar wind was faster and less dense in the north than in the south. These asymmetries persist in the most recent high- and mid-latitude data but are less pronounced. As of July 1, 1996 the northern fast solar wind has lacked any strong stream interactions or shocks and, although a comprehensive search has not yet been made, no CMEs have yet been identified during this interval. On the other hand, Alfv{acute e}nic, compressional, and pressure balanced features are abundant at high latitudes. The most recent data, at 4 AU and 32{degrees}N, has begun to show the effects of solar rotation modulated features in the form of recurrent compressed regions.

  2. Modeling of the atmospheric response to a strong decrease of the solar activity

    NASA Astrophysics Data System (ADS)

    Rozanov, Eugene V.; Egorova, Tatiana A.; Shapiro, Alexander I.; Schmutz, Werner K.

    2012-07-01

    We estimate the consequences of a potential strong decrease of the solar activity using the model simulations of the future driven by pure anthropogenic forcing as well as its combination with different solar activity related factors: total solar irradiance, spectral solar irradiance, energetic electron precipitation, solar protons and galactic cosmic rays. The comparison of the model simulations shows that introduced strong decrease of solar activity can lead to some delay of the ozone recovery and partially compensate greenhouse warming acting in the direction opposite to anthropogenic effects. The model results also show that all considered solar forcings are important in different atmospheric layers and geographical regions. However, in the global scale the solar irradiance variability can be considered as the most important solar forcing. The obtained results constitute probably the upper limit of the possible solar influence. Development of the better constrained set of future solar forcings is necessary to address the problem of future climate and ozone layer with more confidence.

  3. Seismic Holography of the Solar Interior near the Maximum and Minimum of Solar Activity

    NASA Astrophysics Data System (ADS)

    Díaz Alfaro, M.; Pérez Hernández, F.; González Hernández, I.; Hartlep, T.

    2016-06-01

    The base of the convection zone and the tachocline play a major role in the study of the dynamics of the Sun, especially in the solar dynamo. Here, we present a phase-sensitive helioseismic holography method to infer changes in the sound-speed profile of the solar interior. We test the technique using numerically simulated data by Zhao et al. (Astrophys. J. 702, 1150, 2009) with sound-speed perturbations at 0.7 R_{⊙ }. The technique adequately recovers the perturbed sound-speed profile and is seen to be capable of detecting changes in the sound speed as low as 0.05 %. We apply the method to two GONG solar time series of approximately one year, each comprising 13 Bartels rotations, BR2295-BR2307 and BR2387-BR2399, near the maximum and at a minimum of solar activity, respectively. We successfully recover a sound-speed variation with respect to a standard solar model, consistent with previous results. However, we fail to recover a realistic sound-speed variation between maximum and minimum.

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

    NASA Astrophysics Data System (ADS)

    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).

  5. Bimodal solar system based on a ultra-high-temperature TEC

    NASA Astrophysics Data System (ADS)

    Ogloblin, B. G.; Kirillov, E. Ya.; Klimov, A. V.; Shalaev, A. I.; Shumov, D. P.; Ender, A. Ya.; Kuznetsov, V. I.; Sitnov, V. I.

    1996-03-01

    The paper considers an ecological, solar, bimodal system with ultra-high temperature thermionic energy converter (TEC). The solar bimodal Space Electric Propulsion System (SEPS) characteristics are presented.

  6. Major geomagnetic storm due to solar activity (2006-2013).

    NASA Astrophysics Data System (ADS)

    Tiwari, Bhupendra Kumar

    Major geomagnetic storm due to solar activity (2006-2013). Bhupendra Kumar Tiwari Department of Physics, A.P.S.University, Rewa(M.P.) Email: - btiwtari70@yahoo.com mobile 09424981974 Abstract- The geospace environment is dominated by disturbances created by the sun, it is observed that coronal mass ejection (CME) and solar flare events are the causal link to solar activity that produces geomagnetic storm (GMS).CMEs are large scale magneto-plasma structures that erupt from the sun and propagate through the interplanetary medium with speeds ranging from only a few km/s to as large as 4000 km/s. When the interplanetary magnetic field associated with CMEs impinges upon the earth’s magnetosphere and reconnect occur geomagnetic storm. Based on the observation from SOHO/LASCO spacecraft for solar activity and WDC for geomagnetism Kyoto for geomagnetic storm events are characterized by the disturbance storm time (Dst) index during the period 2006-2013. We consider here only intense geomagnetic storm Dst <-100nT, are 12 during 2006-2013.Geomagnetic storm with maximum Dst< -155nT occurred on Dec15, 2006 associated with halo CME with Kp-index 8+ and also verify that halo CME is the main cause to produce large geomagnetic storms.

  7. High-Efficiency Solar Thermal Vacuum Demonstration Completed for Refractive Secondary Concentrator

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.

    2001-01-01

    Common to many of the space applications that utilize solar thermal energy--such as electric power conversion, thermal propulsion, and furnaces--is a need for highly efficient, solar concentration systems. An effort is underway at the NASA Glenn Research Center to develop the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, the refractive secondary concentrator enables very high system concentration ratios (10,000 to 1) and very high temperatures (>2000 K). The innovative refractive secondary concentrator offers significant advantages over all other types of secondary concentrators. The refractive secondary offers the highest throughput efficiency, provides for flux tailoring, requires no active cooling, relaxes the pointing and tracking requirements of the primary concentrator, and enables very high system concentration ratios. This technology has broad applicability to any system that requires the conversion of solar energy to heat. Glenn initiated the development of the refractive secondary concentrator in support of Shooting Star, a solar thermal propulsion flight experiment, and continued the development in support of Space Solar Power.

  8. Flat-plate solar array project. Volume 4: High-efficiency solar cells

    NASA Technical Reports Server (NTRS)

    Leipold, M.; Cheng, L.; Daud, T.; Mokashi, A.; Burger, D.; Christensen, E. (Editor); Murry, J. (Editor); Bengelsdorf, I. (Editor)

    1986-01-01

    The High Efficiency Solar Cell Task was assigned the objective of understanding and developing high efficiency solar cell devices that would meet the cost and performance goals of the Flat Plate Solar Array (FSA) Project. The need for research dealing with high efficiency devices was considered important because of the role efficiency plays in reducing price per watt of generated energy. The R&D efforts conducted during the 1982 to 1986 period are summarized to provide understanding and control of energy conversion losses associated with crystalline silicon solar cells. New levels of conversion efficiency were demonstrated. Major contributions were made both to the understanding and reduction of bulk and surface losses in solar cells. For example, oxides, nitrides, and polysilicon were all shown to be potentially useful surface passivants. Improvements in measurement techniques were made and Auger coefficients and spectral absorption data were obtained for unique types of silicon sheets. New modelling software was developed including a program to optimize a device design based on input characteristics of a cell.

  9. Some Daytime Activities in Solar Astronomy

    NASA Astrophysics Data System (ADS)

    Burin, Michael J.

    2016-01-01

    This century's transits of Venus (2004, 2012) captured significant public attention, reminding us that the wonders of astronomy need not be confined to the night. And while nighttime telescope viewing gatherings (a.k.a. "star parties") are perennially popular, astronomy classes are typically held in the daytime. The logistics of coordinating students outside of class can often be problematic, leading to dark-sky activities that are relegated to extra credit for only those who can attend.

  10. High Efficiency Pb-In Binary Metal Perovskite Solar Cells.

    PubMed

    Wang, Zhao-Kui; Li, Meng; Yang, Ying-Guo; Hu, Yun; Ma, Heng; Gao, Xing-Yu; Liao, Liang-Sheng

    2016-08-01

    Mixed Pb-In perovskite solar cells are fabricated by using lead(II) chloride and indium(III) chloride with methylammonium iodide. A maximum power conversion efficiency as high as 17.55% is achieved owing to the high quality of perovskites with multiple ordered crystal orientations. PMID:27184107

  11. Design for the fabrication of high efficiency solar cells

    DOEpatents

    Simmons, Joseph H.

    1998-01-01

    A method and apparatus for a photo-active region for generation of free carriers when a first surface is exposed to optical radiation. The photo-active region includes a conducting transparent matrix and clusters of semiconductor materials embedded within the conducting transparent matrix. The clusters are arranged in the matrix material so as to define at least a first distribution of cluster sizes ranging from those with the highest bandgap energy near a light incident surface of the photo-active region to those with the smallest bandgap energy near an opposite second surface of the photo-active region. Also disclosed is a method and apparatus for a solar cell. The solar cell includes a photo-active region containing a plurality of semiconductor clusters of varying sizes as described.

  12. Testing the potential of 10Be in varved sediments from two lakes for solar activity reconstruction

    NASA Astrophysics Data System (ADS)

    Czymzik, Markus; Muscheler, Raimund; Brauer, Achim; Adolphi, Florian; Ott, Florian; Kienel, Ulrike; Dräger, Nadine; Slowinski, Michal; Aldahan, Ala; Possnert, Göran

    2015-04-01

    The potential of 10Be in annually laminated (varved) lake sediments for solar activity reconstruction is, to date, largely unexplored. It is hypothesized that 10Be contents in sediments from well-chosen lakes reflect the solar induced atmospheric production signal. The varved nature of these archives provides the chance to establish solar activity time-series with very high temporal precision. However, so far solar activity reconstruction from 10Be in varved lake sediments is hampered due to a lack of detailed knowledge of the process chain from production in the atmosphere to deposition on the lake floor. Calibrating 10Be time-series from varved lake sediments against complementary proxy records from the same sediment archive as well as instrumental meteorological and solar activity data will allow a process-based understanding of 10Be deposition in these lakes and a quantitative evaluation of their potential for solar activity reconstruction. 10Be concentration and flux time-series at annual resolution were constructed for the period 1983 to 2007 (approx. solar cycles 22 and 23) conducting accelerator mass spectrometry and varve chronology on varved sediments of Lakes Tiefer See and Czechowski, located on an east-west transect at a distance of about 450 km in the lowlands of northern-central Europe. 10Be concentrations vary between 0.9 and 1.8*108atoms/g, with a mean of 1.3*108atoms/g in Lake Tiefer See and between 0.6 and 1.6*108atoms/g, with a mean of 1*108atoms/g in Lake Czechowski. Calculated mean 10Be flux is 2.3*108atoms/cm2/year for Lake Tiefer See and 0.7*108atoms/cm2/year for Lake Czechowski. Calibrating the 10Be time-series against corresponding geochemical μ-XRF profiles, varve thickness and total organic carbon records as well as precipitation data from the nearby stations Schwerin for Lake Tiefer See and Koscierzyna for Lake Czechowski and a neutron monitor record of solar activity suggests (1) a complex interaction of varying processes influencing

  13. Interplanetary proton flux and solar wind conditions for different solar activities interacting with spacecraft and astronauts in space

    NASA Astrophysics Data System (ADS)

    Nejat, Cyrus

    2014-01-01

    The goal of this research is to determine the interplanetary proton flux and solar wind conditions by using data from several satellites such as Advanced Composition Explorer (ACE), Geostationary Operational Environmental Satellites (GOES) in particular GOES 9, GOES 11, GOES 12, GOES 13, and Solar Heliospheric Observatory (SOHO) to determine proton flux in different solar wind conditions. The data from above satellites were used to determine space weather conditions in which the goals are to evaluate proton fluxes for four periods of solar cycle activity: a solar cycle 23/24 minimum (2008), close to a solar cycle 22/23 minimum (1997), with intermediate activity (2011) and for about maximum activity for the cycle 23 (2003), to compare data of two period of solar cycle in 2003 and 2008 (Max vs. Min), to compare data of two period of solar cycle in 1997 and 2008 (Min vs. Min), to compare soft X-ray flux from SOHO with proton 1-10 MeV flux from GOES 9 for strong flare in 1997. To conclude the above evaluations are being used to determine the interaction between the space weather conditions and the following consequences of these conditions important for astronautics and everyday human activity: 1- Satellite and Spacecraft charging, 2-Dangerous conditions for onboard electronics and astronauts during strong solar flare events, and 3- Total Electron Content (TEC), Global Positioning System (GPS), and radio communication problems related to solar activity.

  14. Proton Radiation Belt Dynamics in Low Earth Orbits Interrelated with Solar Activity

    NASA Astrophysics Data System (ADS)

    Malakhov, Vitaly; Aleksandrin, Sergey; Mikhailov, Vladimir; Bakaldin, Alexey; Mayorov, Andrey; Mayorova, Marina; Koldashov, Sergey; Sharonova, Nadezhda; Galper, Arkady; Zharaspaev, Temir; Batischev, Alexey

    Existing empirical radiation belt models do not able to calculate trapped particle fluxes with taking into account changing solar activity. Widely using AP-8 model allows to evaluate proton fluxes just in two cases: for minimum or maximum of a solar cycle. New AP-9 model is under developing. Also new additional possibilities for experimental study of radiation belt dynamics is opened up. Since 2006 year PAMELA and ARINA experiments onboard satelite RESURS-DK1 are carried out. PAMELA is in the first place spectrometer to study antiparticles in cosmic rays. The ARINA instrument is intended studying high-energy charged particle bursts in the magnetosphere. Along with such fundamental goals these instruments give opportunity to carry out measurements of trapped particles in the inner radiation belt. Complex of two mentioned instruments covers proton energy range from 30 MeV up to energy limit for trapping (~2 GeV). Continuous measurements with PAMELA and ARINA include falling and rising phases of 23/24 solar cycles. In this report we present temporal profile of proton fluxes in the inner zone of the radiation belt (1.11solar activity (sunspot number) was revealed. At that it was shown that proton fluxes of energies >30MeV at the solar minimum several times greater than at the solar maximum.

  15. Ulysses Composition, Plasma and Magnetic Field Observations of High Speed Solar wind Streams

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1997-01-01

    During 1992-3 as the Ulysses spacecraft passed in and out of the southern high speed solar wind stream, the Solar Wind Ion Spectrometer, SWICS made continuous composition and temperature measurements of all major solar wind ions.

  16. Seismic Study of the Solar Interior: Inferences from SOI/MDI Observations During Solar Activity

    NASA Technical Reports Server (NTRS)

    Korzennik, Sylvain G.; Wagner, William J. (Technical Monitor)

    2005-01-01

    Work on the structure, asphericity and dynamics of the solar interior from p-mode frequencies and frequency splittings was carried out primarily in collaboration with Dr. Eff-Darwich (University of La Laguna, Tenerife). This ongoing collaboration produced new results for the inversion of the internal solar rotation rate and further development in inversion methodologies. It also resulted in inferences on the solar stratification. Substantial progress towards the characterization of high-degree p-modes has been achieved. In collaboration with Drs. Rabello-Soares and Schou (Stanford University), we have gained a clear conceptual understanding of the various elements that affect the leakage matrix of the SOI/MDI instrument. This work has precise implications on the properties and the characterization of the HMI instrument being developed for the SDO mission.

  17. Singular year of high geomagnetic responses to the same solar wind input

    NASA Astrophysics Data System (ADS)

    Yamauchi, Masatoshi; Olsthoorn, Bart; Nicolaou, Georgios

    2016-04-01

    Using high-resolution (5 min) solar wind data and westward auroral electrojet index (AL) index since 1981, temporal variation of the Sun-Earth coupling efficiency (AL response to the solar wind electromagnetic energy/flux input) was examined. To separate the seasonal variation, 3-month averaged statistics is used. (1) The Sun-Earth coupling efficiency for moderate solar wind input occasionally increased beyond the seasonal variation for about half a year during the declining phase of solar cycles; (2) Excluding these singular years and seasonal variation, the Sun-Earth coupling efficiency for moderate or low solar wind input continuously decreased over the past three decades; (3) These temporal variations do not correlate with F10.7 index (proxy for the Solar UV flux). The results confirm some of the previous study using 1-hour resolution data with a better accuracy, and suggest that the existence of additional controlling mechanisms either at the Sun (e.g., magnetic field or solar cycle strength) or solar wind-magnetosphere-ionosphere coupling (e.g., through the solar wind composition). On the other hand, the Sun-Earth coupling efficiency for large solar wind input is very variable and the present correlation method is not sufficient to determine the conditions for large AL activities and its temporal variation. Acknowledgement: Auroral electrojet (AE) indices and sunspot numbers (RI) are official IAGA and IAA endorsed indices that are provided by World Data Center for Geomagnetism, Kyoto University, Japan (AE) and the Royal Observatory of Belgium, Brussels (RI). Including these indices, all data in 5-minutes values are obtained from NASA-GSFC/SPDF through OMNIWeb (http://omniweb.gsfc.nasa.gov/ow.html).

  18. High transmission glasses for solar applications

    SciTech Connect

    Johnson, L.K.; Thompson, D.A.

    1981-11-03

    The instant invention is directed to glasses manifesting solar transmissions (350-2100 nm) through a 2.54 mm thick sheet in excess of 90% which can be prepared from conventional glass batch materials containing up to 0.1% iron, expressed as Fe/sub 2/O/sub 3/, as impurities. The inventive glasses consist essentially, expressed in weight percent on the oxide basis as calculated from the batch, of -Al/sub 2/O/sub 3/ 7-13 -B/sub 2/O/sub 3/ 7-10 -Na/sub 2/O 6-11 -K/sub 2/O 2-7 -CaO 2-7 TiO/sub 2/ 0.1-1 -As/sub 2/O/sub 3/ 0-1 -Sb/sub 2/O/sub 3/ 0-1 -SiO/sub 2/. Balance part of the batch materials is added in the form of nitrates in a sufficient amount to virtually completely oxidize all the tramp iron present to the Fe/sup +3/ state.

  19. Refractive Secondary Solar Concentrator Demonstrated High-Temperature Operation

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.

    2002-01-01

    Space applications that utilize solar thermal energy--such as electric power conversion systems, thermal propulsion systems, and furnaces--require highly efficient solar concentration systems. The NASA Glenn Research Center is developing the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, such as inflatable thin films, the refractive secondary concentrator enables very high system concentration ratios and very high temperatures. Last year, Glenn successfully demonstrated a secondary concentrator throughput efficiency of 87 percent, with a projected efficiency of 93 percent using an antireflective coating. Building on this achievement, Glenn recently successfully demonstrated high-temperature operation of the secondary concentrator when it was used to heat a rhenium receiver to 2330 F. The high-temperature demonstration of the concentrator was conducted in Glenn's 68-ft long Tank 6 thermal vacuum facility equipped with a solar simulator. The facility has a rigid panel primary concentrator that was used to concentrate the light from the solar simulator onto the refractive secondary concentrator. NASA Marshall Space Flight Center provided a rhenium cavity, part of a solar thermal propulsion engine, to serve as the high-temperature receiver. The prototype refractive secondary concentrator, measuring 3.5 in. in diameter and 11.2 in. long, is made of single-crystal sapphire. A water-cooled splash shield absorbs spillage light outside of the 3.5-in. concentrator aperture. Multilayer foil insulation composed of tungsten, molybdenum, and niobium is used to minimize heat loss from the hightemperature receiver. A liquid-cooled canister calorimeter is used to measure the heat loss through the multilayer foil insulation.

  20. Activity trends in young solar-type stars

    NASA Astrophysics Data System (ADS)

    Lehtinen, J.; Jetsu, L.; Hackman, T.; Kajatkari, P.; Henry, G. W.

    2016-04-01

    Aims: We study a sample of 21 young and active solar-type stars with spectral types ranging from late F to mid K and characterize the behaviour of their activity. Methods: We apply the continuous period search (CPS) time series analysis method on Johnson B- and V-band photometry of the sample stars, collected over a period of 16 to 27 years. Using the CPS method, we estimate the surface differential rotation and determine the existence and behaviour of active longitudes and activity cycles on the stars. We supplement the time series results by calculating new log R'HK = log F'HK/σTeff4 emission indices for the stars from high resolution spectroscopy. Results: The measurements of the photometric rotation period variations reveal a positive correlation between the relative differential rotation coefficient and the rotation period as k ∝ Prot1.36, but do not reveal any dependence of the differential rotation on the effective temperature of the stars. Secondary period searches reveal activity cycles in 18 of the stars and temporary or persistent active longitudes in 11 of them. The activity cycles fall into specific activity branches when examined in the log Prot/Pcyc vs. log Ro-1, where Ro-1 = 2Ωτc, or log Prot/Pcyc vs. log R'HK diagram. We find a new split into sub-branches within this diagram, indicating multiple simultaneously present cycle modes. Active longitudes appear to be present only on the more active stars. There is a sharp break at approximately log R'HK = -4.46 separating the less active stars with long-term axisymmetric spot distributions from the more active ones with non-axisymmetric configurations. In seven out of eleven of our stars with clearly detected long-term non-axisymmetric spot activity the estimated active longitude periods are significantly shorter than the mean photometric rotation periods. This systematic trend can be interpreted either as a sign of the active longitudes being sustained from a deeper level in the stellar interior

  1. Thermocleavable materials for polymer solar cells with high open circuit voltage-a comparative study.

    PubMed

    Tromholt, Thomas; Gevorgyan, Suren A; Jørgensen, Mikkel; Krebs, Frederik C; Sylvester-Hvid, Kristian O

    2009-12-01

    The search for polymer solar cells giving a high open circuit voltage was conducted through a comparative study of four types of bulk-heterojunction solar cells employing different photoactive layers. As electron donors the thermo-cleavable polymer poly-(3-(2-methylhexyloxycarbonyl)dithiophene) (P3MHOCT) and unsubstituted polythiophene (PT) were used, the latter of which results from thermo cleaving the former at 310 degrees C. As reference, P3HT solar cells were built in parallel. As electron acceptors, either PCBM or bis-[60]PCBM were used. In excess of 300 solar cells were produced under as identical conditions as possible, varying only the material combination of the photo active layer. It was observed that on replacing PCBM with bis[60]PCBM, the open circuit voltage on average increased by 100 mV for P3MHOCT and 200 mV for PT solar cells. Open circuit voltages approaching 1 V were observed for the PT:bis[60]PCBM solar cells and a maximum conversion efficiency of 1.3% was obtained for solar cells with P3MHOCT:PCBM as the photoactive material. For the reference solar cells maximum efficiencies of 2.1 and 2.4% were achieved for P3HT:PCBM and P3HT:bis[60]PCBM, respectively. Despite special measures taken in terms of substrate design and device processing, a substantial spread in the photovoltaic properties was generally observed. This spread could not be correlated with the optical properties of the solar cells, the thickness of the photo active layer or the electrode deposition conditions of the aluminum top electrode. PMID:20356155

  2. Development of advanced algorithms to detect, characterize and forecast solar activities

    NASA Astrophysics Data System (ADS)

    Yuan, Yuan

    Study of the solar activity is an important part of space weather research. It is facing serious challenges because of large data volume, which requires application of state-of-the-art machine learning and computer vision techniques. This dissertation targets at two essential aspects in space weather research: automatic feature detection and forecasting of eruptive events. Feature detection includes solar filament detection and solar fibril tracing. A solar filament consists of a mass of gas suspended over the chromosphere by magnetic fields and seen as a dark, ribbon-shaped feature on the bright solar disk in Halpha (Hydrogen-alpha) full-disk solar images. In this dissertation, an automatic solar filament detection and characterization method is presented. The investigation illustrates that the statistical distribution of the Laplacian filter responses of a solar disk contains a special signature which can be used to identify the best threshold value for solar filament segmentation. Experimental results show that this property holds across different solar images obtained by different solar observatories. Evaluation of the proposed method shows that the accuracy rate for filament detection is more than 95% as measured by filament number and more than 99% as measured by filament area, which indicates that only a small fraction of tiny filaments are missing from the detection results. Comparisons indicate that the proposed method outperforms a previous method. Based on the proposed filament segmentation and characterization method, a filament tracking method is put forward, which is capable of tracking filaments throughout their disk passage. With filament tracking, the variation of filaments can be easily recorded. Solar fibrils are tiny dark threads of masses in Halpha images. It is generally believed that fibrils are magnetic field-aligned, primarily due to the reason that the high electrical conductivity of the solar atmosphere freezes the ionized mass in

  3. Solar Energy Experiments for High School and College Students.

    ERIC Educational Resources Information Center

    Norton, Thomas W.; And Others

    This publication contains eighteen experiments and eight classroom activities. The experiments are of varying difficulty and cover the important aspects of solar energy utilization. Each experiment is self-contained, with its own introduction and background information. Energy measurements are emphasized and techniques for collector efficiency…

  4. Water Impacts of High Solar PV Electricity Penetration

    SciTech Connect

    Macknick, Jordan; Cohen, Stuart

    2015-09-01

    This analysis provides a detailed national and regional description of the water-related impacts and constraints of high solar electricity penetration scenarios in the U.S. in 2030 and 2050. A modified version of the Regional Energy Deployment System (ReEDS) model that incorporates water resource availability and costs as a constraint in each of its 134 Balancing Area (BA) regions was utilized to explore national and regional differences in water use impacts and solar deployment locations under different solar energy cost and water availability scenarios (Macknick et al. 2015). Water resource availability and cost data are from recently completed research at Sandia National Laboratories (Tidwell et al. 2013a). Scenarios analyzed include two business-as-usual solar energy cost cases, one with and one without considering available water resources, and four solar energy cost cases that meet the SunShot cost goals (i.e., $1/watt for utility-scale PV systems), with varying levels of water availability restrictions. This analysis provides insight into the role solar energy technologies have in the broader electricity sector under scenarios of water constraints.

  5. A High-Efficiency Refractive Secondary Solar Concentrator for High Temperature Solar Thermal Applications

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael F., Jr.; Macosko, Robert P.

    2000-01-01

    A refractive secondary solar concentrator is a non-imaging optical device that accepts focused solar energy from a primary concentrator and redirects that light, by means of refraction and total internal reflection (TIR) into a cavity where the solar energy is used for power and/or propulsion applications. This concept offers a variety of advantages compared to typical reflective secondary concentrators (or the use of no secondary at all): higher optical efficiency, minimal secondary cooling requirements, a smaller cavity aperture, a reduction of outgassing from the cavity and flux tailoring of the solar energy within the heat receiver. During the past 2 years, NASA Lewis has been aggressively developing this concept in support of the NASA Marshall Shooting Star Flight Experiment. This paper provides a brief overview of the advantages and technical challenges associated with the development of a refractive secondary concentrator and the fabrication of a working unit in support of the flight demonstration program.

  6. Coronal mass ejections in the solar wind at high solar latitudes: An overview

    NASA Technical Reports Server (NTRS)

    Gosling, Jack T.

    1994-01-01

    Ulysses provided the first direct measurements of coronal mass ejections (CME's) in the solar wind at high heliographic latitudes. An overview of new results from the plasma experiment on Ulysses and magnetic field measurements, during the spacecraft's first excursion to high solar latitudes are summarized. A striking aspect of the high-latitude CME's observed is that they all had high speeds, with the overall average speed being 730 km/sec. A new class of forward-reverse shock pairs, associated with expansion of CME's was discovered at high latitudes. Of six certain CME's observed at high latitudes, three have associated shock pairs of this nature. Combined Ulysses and Yohkoh observations suggest that the flux rope topology characteristic of some CME's results from reconnection within the legs of neighboring magnetic loops embedded within the escaping CME's.

  7. Coronal mass ejections in the solar wind at high solar latitudes: An overview

    SciTech Connect

    Gosling, J.T.

    1994-10-01

    Ulysses has provided the first direct measurements of coronal mass ejections, CMES, in the solar wind at high heliographic latitudes. This paper provides an overview of new and unexpected results from the plasma experiment on Ulysses, supplemented with magnetic field measurements, during the spacecraft`s first excursion to high solar latitudes. A striking aspect of the high-latitude CMEs observed is that they all had high speeds, with the overall average speed being 730 km s{sup {minus}1}. A new class of forward-reverse shock pairs, associated with expansion of CMES, has been discovered at high latitudes. Of six certain CMEs observed at high latitudes, three have associated shock pairs of this nature. Combined Ulysses and Yohkoh observations suggest that the flux rope topology characteristic of some CMEs results from reconnection within the legs of neighboring magnetic loops embedded within the escaping CMES.

  8. New Monolithic High Solar Rejection EUV Transmission Filter

    NASA Astrophysics Data System (ADS)

    Fleury-Frenette, Karl; Renotte, Etienne; Lenaerts, C.; Rossi, Laurence; Jacques, Lionel; Halain, Jean-Philippe; Rochus, Pierre

    A new high solar rejection transmission filter for the extreme UV has been developed for the Solar Orbiter Extreme Ultraviolet Imager (EUI). To provide enhanced resilience to high thermal load, a monolithic architecture approach has been taken in order to limit the thermal contact resistance between the filtering sub-micron thin film, its supporting mesh, and holding frame. Some aspects of the manufacturing process involving thin film deposition and photolithography will be presented along with optical performance and space environmental test results. New avenues for improving the thermo-optical properties of the filter will also be discussed.

  9. Theoretical Problems in High Resolution Solar Physics, 2

    NASA Technical Reports Server (NTRS)

    Athay, G. (Editor); Spicer, D. S. (Editor)

    1987-01-01

    The Science Working Group for the High Resolution Solar Observatory (HRSO) laid plans beginning in 1984 for a series of workshops designed to stimulate a broadbased input from the scientific community to the HRSO mission. These workshops have the dual objectives of encouraging an early start on the difficult theoretical problems in radiative transfer, magnetohydrodynamics, and plasma physics that will be posed by the HRSO data, and maintaining current discussions of results in high resolution solar studies. This workshop was the second in the series. The workshop format presented invited review papers during the formal sessions and contributed poster papers for discussions during open periods. Both are presented.

  10. Long-term persistence of solar activity. [Abstract only

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

    1994-01-01

    The solar irradiance has been found to change by 0.1% over the recent solar cycle. A change of irradiance of about 0.5% is required to effect the Earth's climate. How frequently can a variation of this size be expected? We examine the question of the persistence of non-periodic variations in solar activity. The Huerst exponent, which characterizes the persistence of a time series (Mandelbrot and Wallis, 1969), is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD (Stuiver and Pearson, 1986). We find a constant Huerst exponent, suggesting that solar activity in the frequency range of from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately equal to 0.8, is significantly larger than the value of 0.5 that would correspond to variations produced by a white-noise process. This value is in good agreement with the results for the monthly sunspot data reported elsewhere, indicating that the physics that produces the continuum is a correlated random process (Ruzmaikin et al., 1992), and that is is the same type of process over a wide range of time interval lengths. We conclude that the time period over which an irradiance change of 0.5% can be expected to occur is significantly shorter than that which would be expected for variations produced by a white-noise process.

  11. Solar activity and modulation of the cosmic ray intensity

    NASA Technical Reports Server (NTRS)

    Akasofu, S.-I.; Olmsted, C.; Lockwood, J. A.

    1985-01-01

    Since its discovery by Forbush (1954), the 11-year cycle modulation of the cosmic ray intensity has been studied extensively. Bowe and Hatton (1982) obtained a well-behaved transfer function F between the solar activity S and the cosmic ray intensity modulation Io-I. They suggested that the 11-year variation for sunspot cycle 20 can be attributed to the modulating effect of solar flare-induced shocks propagating through the heliosphere. The cosmic ray intensity in the absence of solar activity is denoted by Io, while I denotes the observed intensity. Bowe and Hatton infer that the boundary of the heliosphere is located at a distance of 70-90 AU. Since their conclusion is of great importance in understanding the mechanism of the 11-year modulation, the present investigation is concerned with a repetition of their study for two cycles, taking into account the use of a slightly modified method. The obtained results confirm the conclusions reached by Bowe and Hatton that there is a well-behaved transfer function for solar flares.

  12. High Energy Solar Spectroscopic Imager (HESSI) Team Investigations

    NASA Technical Reports Server (NTRS)

    Emslie, A. Gordon

    1998-01-01

    This report covers activities on the above grant for the period through the end of September 1997. The work originally proposed to be performed under a three-year award was converted at that time to a two-year award for the remainder of the period, and is now funded under award NAGS-4027 through Goddard Space Flight Center. The P.I. is a co-investigator on the High Energy Solar Spectroscopic Imager (HESSI) team, selected as a Small-Class Explorer (SNMX) mission in 1997. He has also been a participant in the Space Physics Roadmap Planning Group. Our research has been strongly influenced by the NASA mission opportunities related to these activities. The report is subdivided into four sections, each dealing with a different aspect of our research within this guiding theme. Personnel involved in this research at UAH include the P.I. and graduate students Michele Montgomery and Amy Winebarger. Much of the work has been carried out in collaboration with investigators at other institutions, as detailed below. Attachment: Laser wakefield acceleration and astrophysical applications.

  13. High Energy Solar Spectroscopic Imager (HESSI) Team Investigations

    NASA Astrophysics Data System (ADS)

    Emslie, A. Gordon

    1998-04-01

    This report covers activities on the above grant for the period through the end of September 1997. The work originally proposed to be performed under a three-year award was converted at that time to a two-year award for the remainder of the period, and is now funded under award NAGS-4027 through Goddard Space Flight Center. The P.I. is a co-investigator on the High Energy Solar Spectroscopic Imager (HESSI) team, selected as a Small-Class Explorer (SNMX) mission in 1997. He has also been a participant in the Space Physics Roadmap Planning Group. Our research has been strongly influenced by the NASA mission opportunities related to these activities. The report is subdivided into four sections, each dealing with a different aspect of our research within this guiding theme. Personnel involved in this research at UAH include the P.I. and graduate students Michele Montgomery and Amy Winebarger. Much of the work has been carried out in collaboration with investigators at other institutions, as detailed below. Attachment: Laser wakefield acceleration and astrophysical applications.

  14. Solar activity impact on the Earth's upper atmosphere

    NASA Astrophysics Data System (ADS)

    Kutiev, Ivan; Tsagouri, Ioanna; Perrone, Loredana; Pancheva, Dora; Mukhtarov, Plamen; Mikhailov, Andrei; Lastovicka, Jan; Jakowski, Norbert; Buresova, Dalia; Blanch, Estefania; Andonov, Borislav; Altadill, David; Magdaleno, Sergio; Parisi, Mario; Miquel Torta, Joan

    2013-02-01

    The paper describes results of the studies devoted to the solar activity impact on the Earth's upper atmosphere and ionosphere, conducted within the frame of COST ES0803 Action. Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject. Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis, empirical modeling, electron density profile reconstruction, and forecasting techniques. Results: Results are grouped in three sections: Medium- and long-term ionospheric response to the changes in solar and geomagnetic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques. Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV) radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity. Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere. Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data.

  15. Stellar activity as noise in exoplanet detection - I. Methods and application to solar-like stars and activity cycles

    NASA Astrophysics Data System (ADS)

    Korhonen, H.; Andersen, J. M.; Piskunov, N.; Hackman, T.; Juncher, D.; Järvinen, S. P.; Jørgensen, U. G.

    2015-04-01

    The detection of exoplanets using any method is prone to confusion due to the intrinsic variability of the host star. We investigate the effect of cool starspots on the detectability of the exoplanets around solar-like stars using the radial velocity method. For investigating this activity-caused `jitter' we calculate synthetic spectra using radiative transfer, known stellar atomic and molecular lines, different surface spot configurations and an added planetary signal. Here, the methods are described in detail, tested and compared to previously published studies. The methods are also applied to investigate the activity jitter in old and young solar-like stars, and over a solar-like activity cycles. We find that the mean full jitter amplitude obtained from the spot surfaces mimicking the solar activity varies during the cycle approximately between 1 and 9 m s-1. With a realistic observing frequency a Neptune-mass planet on a 1-yr orbit can be reliably recovered. On the other hand, the recovery of an Earth-mass planet on a similar orbit is not feasible with high significance. The methods developed in this study have a great potential for doing statistical studies of planet detectability, and also for investigating the effect of stellar activity on recovered planetary parameters.

  16. Collecting Solar Energy. Solar Energy Education Project.

    ERIC Educational Resources Information Center

    O'Brien, Alexander

    This solar energy learning module for use with junior high school students offers a list of activities, a pre-post test, job titles, basic solar energy vocabulary, and diagrams of solar energy collectors and installations. The purpose is to familiarize students with applications of solar energy and titles of jobs where this knowledge could be…

  17. The influence of nonstationarity of the solar activity and general solar field on modulation of cosmic rays

    NASA Technical Reports Server (NTRS)

    Zusmanovich, A. G.; Kryakunova, O. N.; Churunova, L. F.; Shvartsman, Y. E.

    1985-01-01

    A numerical model of the propagation of galactic cosmic rays in interplanetary space was constructed for the case when the modulation depth determined by the level of solar activity changed in time. Also the contribution of particle drift in the regular field was calculated, and the agreement with experimental data concerning the ratio of protons and electrons in two solar activity minima is shown.

  18. Process Development for High Voc CdTe Solar Cells

    SciTech Connect

    Ferekides, C. S.; Morel, D. L.

    2011-05-01

    This is a cumulative and final report for Phases I, II and III of this NREL funded project (subcontract # XXL-5-44205-10). The main research activities of this project focused on the open-circuit voltage of the CdTe thin film solar cells. Although, thin film CdTe continues to be one of the leading materials for large-scale cost-effective production of photovoltaics, the efficiency of the CdTe solar cells have been stagnant for the last few years. This report describes and summarizes the results for this 3-year research project.

  19. HIGH SPATIAL RESOLUTION OBSERVATIONS OF LOOPS IN THE SOLAR CORONA

    SciTech Connect

    Brooks, David H.; Ugarte-Urra, Ignacio; Warren, Harry P.; Winebarger, Amy R.

    2013-08-01

    Understanding how the solar corona is structured is of fundamental importance to determine how the Sun's upper atmosphere is heated to high temperatures. Recent spectroscopic studies have suggested that an instrument with a spatial resolution of 200 km or better is necessary to resolve coronal loops. The High Resolution Coronal Imager (Hi-C) achieved this performance on a rocket flight in 2012 July. We use Hi-C data to measure the Gaussian widths of 91 loops observed in the solar corona and find a distribution that peaks at about 270 km. We also use Atmospheric Imaging Assembly data for a subset of these loops and find temperature distributions that are generally very narrow. These observations provide further evidence that loops in the solar corona are often structured at a scale of several hundred kilometers, well above the spatial scale of many proposed physical mechanisms.

  20. Potential high efficiency solar cells: Applications from space photovoltaic research

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1986-01-01

    NASA involvement in photovoltaic energy conversion research development and applications spans over two decades of continuous progress. Solar cell research and development programs conducted by the Lewis Research Center's Photovoltaic Branch have produced a sound technology base not only for the space program, but for terrestrial applications as well. The fundamental goals which have guided the NASA photovoltaic program are to improve the efficiency and lifetime, and to reduce the mass and cost of photovoltaic energy conversion devices and arrays for use in space. The major efforts in the current Lewis program are on high efficiency, single crystal GaAs planar and concentrator cells, radiation hard InP cells, and superlattice solar cells. A brief historical perspective of accomplishments in high efficiency space solar cells will be given, and current work in all of the above categories will be described. The applicability of space cell research and technology to terrestrial photovoltaics will be discussed.

  1. Utilising polyphenylene oxide for high exposure solar UVA dosimetry

    NASA Astrophysics Data System (ADS)

    Turnbull, D. J.; Schouten, P. W.

    2008-05-01

    A personal UV dosimeter that can quantitatively assess high exposure solar UVA exposures has been developed. The chemical polyphenylene oxide has been previously reported on its ability to measure high UVB exposures. This current research has found that polyphenylene oxide, cast in thin film form, is responsive to both the UVA and UVB parts of the solar spectrum. Further to this, the UVB wavelengths were filtered out with the use of mylar. This combined system responded to the UVA wavelengths only and underwent a change in optical absorbance as a result of UVA exposure. Preliminary results indicate that this UVA dosimeter saturates steadily when exposed to sunlight and can measure exposures of more than 20 MJ/m2 of solar UVA radiation with an uncertainty level of no more than ±5%.

  2. OM-VPE grown materials for high efficiency solar cells

    NASA Technical Reports Server (NTRS)

    Saxena, R.; Cooper, B., III; Ludowise, M.; Borden, P.; Gregory, P.

    1980-01-01

    Organometallic sources are available for all the III-V elements and a variety of dopants; thus it is possible to use the technique to grow a wide variety of semiconductor compounds. AlGaAsSb and AlGaInAs alloys for multijunction monolithic solar cells were grown by OM-VPE. While the effort concentrated on terrestrial applications, the success of OM-VPE grown GaAs/AlGaAs concentrator solar cells (23% at 400 suns) demonstrates that OM-VPE is suitable for growing high efficiency solar cells in large quantities for space applications. In addition, OM-VPE offers the potential for substantial cost reduction of photovoltaic devices with scale up and automation and due to high process yield from reproducible, uniform epitaxial growths with excellent surface morphology.

  3. The October-November, 2003 Solar Activity and its Relationship to the "approximately 155 day" Solar Periodicity

    NASA Technical Reports Server (NTRS)

    Richardson, I. G.; Cane, H. V.

    2005-01-01

    Periodicities of - 155 days in various solar and interplanetary phenomena were first discovered during solar cycle 21 and have been shown t o be intermittently present in other solar cycles. In the current solar cycle (23), they have been reported in solar energetic particle events and interplanetary coronal maSS ejections. We assess whether the "unexpected" October - November 2003 burst of solar activity during the late declining phase of the cycle may have been a manifestation of such a periodic behavior, and hence might have been to =me extent "predictable". If the pattern were to continue, episodes of enhanced activity might be expected around April - May and October, 2004. There was a mod- est increase activity increase in mid-April, 2004 which may conform to this pattern.

  4. The October-November, 2003 Solar Activity and its Relationship to the "approx. 155 day" Solar Periodicity

    NASA Technical Reports Server (NTRS)

    Richardson, I. G.; Cane, H. V.

    2004-01-01

    Periodicities of approx. 155 days in various solar and interplanetary phenomena were first discovered during solar cycle 21 and have been shown to be intermittently present in other solar cycles. In the current solar cycle (23), they have been reported in solar energetic particle events and interplanetary coronal mass ejections. We assess whether the "unexpected" October - November 2003 burst of solar activity during the late declining phase of the cycle may have been a manifestation of such a periodic behavior, and hence might have been to some extent "predictable". If the pattern were to continue, episodes of enhanced activity might be expected around April - May and October, 2004. There was a modest increase activity increase in mid-April, 2004 which may conform to this pattern.

  5. How Large Scale Flows in the Solar Convection Zone may Influence Solar Activity

    NASA Technical Reports Server (NTRS)

    Hathaway, D. H.

    2004-01-01

    Large scale flows within the solar convection zone are the primary drivers of the Sun s magnetic activity cycle. Differential rotation can amplify the magnetic field and convert poloidal fields into toroidal fields. Poleward meridional flow near the surface can carry magnetic flux that reverses the magnetic poles and can convert toroidal fields into poloidal fields. The deeper, equatorward meridional flow can carry magnetic flux toward the equator where it can reconnect with oppositely directed fields in the other hemisphere. These axisymmetric flows are themselves driven by large scale convective motions. The effects of the Sun s rotation on convection produce velocity correlations that can maintain the differential rotation and meridional circulation. These convective motions can influence solar activity themselves by shaping the large-scale magnetic field pattern. While considerable theoretical advances have been made toward understanding these large scale flows, outstanding problems in matching theory to observations still remain.

  6. Summary of solar activity observed at the Mauna Loa Solar Observatory: 1980-1983. Technical note

    SciTech Connect

    Rock, K.; Fisher, R.; Garcia, C.; Yasukawa, E.

    1983-11-01

    The following technical note summarizes solar activity observed during the first four years operation of the experiment systems of the Coronal Dynamics Project, which are located at the Mauna Loa Solar Observatory. This short report has been produced with the general aim of providing users of Mauna Loa observations with a summary of data for specific events. So that this table might be as useful as possible, a comprehensive review of three sources was performed. The plain language logs, identified as the so-called observer's logs, the now-discontinued activity logs, and the prominence monitor quality control logs were the sources from which the information in the following tables was obtained. It is expected that this review will be of particular use to those investigators who intend to use both the K-coronameter data base and the SMM Coronagraph-Polarimeter data for the study of coronal transient events.

  7. Astrometry and Photometry of Faint, High Priority Solar System Objects

    NASA Astrophysics Data System (ADS)

    McMillan, Robert S.; Larsen, Jeffrey A.; Scotti, James V.; Bressi, Terrence H.; Maleszewski, Chester K.

    2014-02-01

    We propose to use MOSAIC 1.1 on the Mayall 4-meter telescope to improve knowledge of the orbits and magnitudes of high priority classes of Near Earth Objects (NEOs) and other small solar system bodies that cannot be reached with our Spacewatch telescopes. Many asteroids and comets are being lost owing to insufficient followup astrometry, but only the most important ones can continue to be observed with the limited resources available. Objects flagged as high scientific priority and urgently in need of further observations include freshly discovered virtual impactors (VIs) and NEOs discovered by the soon-to-be reactivated WISE spacecraft. It is better to follow objects longer during their discovery apparitions than to search tens of degrees of arc for them when they return years later, hence our need to reach fainter magnitudes. Other targets for recovery include future targets of radar, NEOs previously detected by WISE with orbits or albedos suggesting potential for cometary activity, potential destinations for spacecraft, and returning NEOs with hard-won albedos and diameters previously determined by WISE in need of astrometry.

  8. Solar Activity and its Impact on Earth's Climate

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.

    2004-01-01

    The Sun's activity is now approaching an expected 2006 minimum, following the dramatic maximum of Solar Cycle 23, that included events such as the 2001 "Bastille Day" Coronal Mass Ejection, and the record-setting Oct-Nov 2003 solar flares, with their associated sunspots and variations in Total Solar Irradiance, or TSI. On Nov 4,2003 the largest X-ray flare ever detected (X-28) was observed in detail. We discuss recent satellite measurements of TSI by ACRIM 2 and 3 and Virgo, and new precision observations of TSI and SSI (Solar Spectral Irradiance) from the SORCE mission, that launched on January 25,2003. TSI variations recorded during the June 8,2004 transit of Venus show the unprecedented precision of the SORCE Total Irradiance Monitor (TIM) instrument, the first of its kind to employ phase-sensitive detection. The SORCE spectral instruments, XPS, Solstice, and SIM, record the Sun's changes over a wide range of wavelengths, from 1 to more than 2000 nanometers, for the first time covering the peak of the solar spectrum, including spectral components that provide energy inputs to key components of the climate system - ultraviolet (UV) into the upper atmospheric ozone layer, infrared (IR) into the lower atmosphere and clouds, and Visible into the Oceans and biosphere. Succeeding satellite missions are planned to monitor both TSI and SSI through Cycle 24. We summarize current ideas about decadal and longer solar variability, and associated potential impacts on Earth's climate on time scales from decades to centuries, especially highlighting the role of feedbacks in the climate system.

  9. Centennial Scale Variations in Lake Productivity Linked to Solar Activity

    NASA Astrophysics Data System (ADS)

    Englebrecht, A.; Bhattacharyya, S.; Guilderson, T. P.; Ingram, L.; Byrne, R.

    2012-12-01

    Solar variations on both decadal and centennial timescales have been associated with climate phenomena (van Loon et al., 2004; Hodell et al., 2001; White et al., 1997). The energy received by the Earth at the peak of the solar cycle increases by <0.1%; so the question has remained of how this could be amplified to produce an observable climate response. Recent modeling shows that the response of the Earth's climate system to the 11-year solar cycle may be amplified through stratosphere and ocean feedbacks and has the potential to impact climate variability on a multidecadal to centennial timescales (Meehl et al., 2009). Here, we report a 1000-year record of changes in the stratigraphy and carbon isotope composition of varved lake sediment from Isla Isabela (22°N, 106°W) in the subtropical northeast Pacific. Stable carbon isotopes and carbonate stratigraphy can be used to infer surface productivity in the lake. Our analysis shows variations in primary productivity on centennial timescales and suggests that solar activity may be an important component of Pacific climate variability. A possible response during solar maxima acts to keep the eastern equatorial Pacific cooler and drier than usual, producing conditions similar to a La Niña event. In the region around Isla Isabela peak solar years were characterized by decreased surface temperatures and suppressed precipitation (Meehl et al., 2009), which enhance productivity at Isabela (Kienel et al. 2011). In the future, we plan to analyze the data using advanced time series analysis techniques like the wavelets together with techniques to handle irregularly spaced time series data. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-571672

  10. Design of a high-power, high-brightness Nd:YAG solar laser.

    PubMed

    Liang, Dawei; Almeida, Joana; Garcia, Dário

    2014-03-20

    A simple high-power, high-brightness Nd:YAG solar laser pumping approach is presented in this paper. The incoming solar radiation is both collected and concentrated by four Fresnel lenses and redirected toward a Nd:YAG laser head by four plane-folding mirrors. A fused-silica secondary concentrator is used to compress the highly concentrated solar radiation to a laser rod. Optimum pumping conditions and laser resonator parameters are found through ZEMAX and LASCAD numerical analysis. Solar laser power of 96 W is numerically calculated, corresponding to the collection efficiency of 24  W/m². A record-high solar laser beam brightness figure of merit of 9.6 W is numerically achieved. PMID:24663463

  11. Origin of photogenerated carrier recombination at the metal-active layer interface in polymer solar cells.

    PubMed

    Kumar, Mukesh; Dubey, Ashish; Reza, Khan Mamun; Adhikari, Nirmal; Qiao, Qiquan; Bommisetty, Venkat

    2015-11-01

    The role of the metal-active layer interface in photogenerated recombination has been investigated using nanoscale current sensing atomic force microscopy (CS-AFM) and intensity modulated photocurrent spectroscopy (IMPS) in as-deposited, pre-annealed and post-annealed bulk heterojunction (BHJ) solar cells. Aluminum (Al) confined post-annealed BHJ solar cells exhibited a significantly improved device efficiency compared to pre-annealed BHJ solar cells having similar photocarrier harvesting ability in the active layer. The nanoscale topography and CS-AFM results indicate a uniform PCBM rich phase at the metal-active layer interface in the post-annealed cells, but PCBM segregation in the pre-annealed cells. These two different annealing processes showed different carrier dynamics revealed using IMPS under various light intensities. The IMPS results suggest reduced photo generated carrier recombination in uniform PCBM rich post-annealed BHJ solar cells. This study reveals the importance of the metal-bend interface in BHJ solar cells in order to obtain efficient charge carrier extraction for high efficiency. PMID:26431263

  12. Global patterns of solar influence on high cloud cover

    NASA Astrophysics Data System (ADS)

    Dima, Mihai; Voiculescu, Mirela

    2016-07-01

    One of the main sources of uncertainty in climate projections is represented by clouds, which have a profound influence on the Earth's radiation budget through the feedbacks in which they are involved. The improvement of clouds representation in General Circulation Models relies largely on constraints derived from observations and on correct identification of processes that influence cloud formation or lifetime. Here we identify solar forced high cloud cover (HCC) patterns in reanalysis and observed data extending over the 1871-2009 period, based on their associations with known fingerprints of the same forcing on surface air temperature, sea surface temperature (SST) and sea level pressure fields. The solar influence on HCC has maximum amplitudes over the Pacific basin, where HCC anomalies are distributed in bands of alternating polarities. The colocation of the HCC and SST anomalies bands indicates a thermal influence on high clouds through convection and an amplification of the HCC anomalies by a positive feedback of long-wave fluxes, which increases the solar signal. Consistent with numerical simulations, the solar forced HCC pattern appears to be generated through a constructive interference between the so-called "top-down" and "bottom-up" mechanisms of solar influence on climate and is amplified by ocean-atmosphere positive feedbacks.

  13. Antifouling property of highly oleophobic substrates for solar cell surfaces

    NASA Astrophysics Data System (ADS)

    Fukada, Kenta; Nishizawa, Shingo; Shiratori, Seimei

    2014-03-01

    Reduction of solar cell conversion efficiency by bird spoor or oil smoke is a common issue. Maintaining the surface of solar cells clean to retain the incident light is of utmost importance. In this respect, there has been growing interest in the area of superhydrophobicity for developing water repelling and self-cleaning surfaces. This effect is inspired by lotus leaves that have micro papillae covered with hydrophobic wax nanostructures. Superhydrophobic surfaces on transparent substrates have been developed for removing contaminants from solar cell surfaces. However, oil cannot be removed by superhydrophobic effect. In contrast, to prevent bird spoor, a highly oleophobic surface is required. In a previous study, we reported transparent-type fabrics comprising nanoparticles with a nano/micro hierarchical structure that ensured both oleophobicity and transparency. In the current study, we developed new highly oleophobic stripes that were constructed into semi-transparent oleophobic surfaces for solar cells. Solar cell performance was successfully maintained; the total transmittance was a key factor for determining conversion efficiency.

  14. High-efficiency solar cell and method for fabrication

    DOEpatents

    Hou, H.Q.; Reinhardt, K.C.

    1999-08-31

    A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD). 4 figs.

  15. High-efficiency solar cell and method for fabrication

    DOEpatents

    Hou, Hong Q.; Reinhardt, Kitt C.

    1999-01-01

    A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD).

  16. Periodic analysis of solar activity and its link with the Arctic oscillation phenomenon

    SciTech Connect

    Qu, Weizheng; Li, Chun; Du, Ling; Huang, Fei; Li, Yanfang

    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 contribution

  17. Solar flare activity changes and global magnetic field disturbances

    NASA Astrophysics Data System (ADS)

    Bumba, V.; Hejna, L.

    1988-01-01

    Published observational data on solar-flare activity in the period 1965-1980 are analyzed statistically and related to changes in the magnetic active longitudes (MALs) identified and studied by Bumba and Hejna (1986). MALs are long strips of single-polarity fields which may persist for about 8-30 rotations and display internal structure. The data sets employed are briefly characterized, and the results are presented graphically. Flare maxima are found to correlate well with MAL disturbances, especially during the ascending phase of the solar cycle and with MALs of negative polarity. The possible implications of these findings for the interplanetary magnetic field and for theoretical models of flare generation are indicated.

  18. GRAND MINIMA AND NORTH-SOUTH ASYMMETRY OF SOLAR ACTIVITY

    SciTech Connect

    Olemskoy, S. V.; Kitchatinov, L. L.

    2013-11-01

    A solar-type dynamo model in a spherical shell is developed with allowance for random dependence of the poloidal field generation mechanism on time and latitude. The model shows repeatable epochs of a strongly decreased amplitude of magnetic cycles similar to the Maunder minimum of solar activity. Random dependence of dynamo parameters on latitude breaks the equatorial symmetry of generated fields. The model shows the correlation of the occurrence of grand minima with deviations in the dynamo field from dipolar parity. An increased north-south asymmetry of magnetic activity can, therefore, be an indicator of transitions to grand minima. Qualitative interpretation of this correlation is suggested. Statistics of grand minima in the model are close to the Poisson random process, indicating that the onset of a grand minimum is statistically independent of preceding minima.

  19. Longitudinal structure of solar activity: Regular and stochastic behavior

    NASA Astrophysics Data System (ADS)

    Erofeev, D. V.

    2015-12-01

    The ratio of regular and stochastic components in the behavior of the longitudinal-temporal distribution of solar activity is studied with the use of correlation and spectral analysis of data on sunspot groups for 12 solar cycles. It was found that data samples of about 10 years in length often (in 50% of cases) show the presence of regular structures in the longitudinal distribution of sunspot groups. However, these structures are nonstationary; their characteristic scales and rotation periods vary when changing from one 10-year interval to another. The behavior of the longitudinal structure of sunspot activity is mainly stochastic on a long time scale (50-100 years); it is characterized by a wide spectrum of spatial scales and a continuous spectrum of rotation periods, which takes a period from 25.6 to 28.5 days.

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

    PubMed

    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. PMID:27450297

  1. Study of Distribution and Asymmetry of Solar Active Prominences during Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Joshi, Navin Chandra; Bankoti, Neeraj Singh; Pande, Seema; Pande, Bimal; Pandey, Kavita

    2009-12-01

    In this article we present the results of a study of the spatial distribution and asymmetry of solar active prominences (SAP) for the period 1996 through 2007 (solar cycle 23). For more meaningful statistical analysis we analyzed the distribution and asymmetry of SAP in two subdivisions viz. Group1 (ADF, APR, DSF, CRN, CAP) and Group2 (AFS, ASR, BSD, BSL, DSD, SPY, LPS). The North - South (N - S) latitudinal distribution shows that the SAP events are most prolific in the 21° to 30° slice in the Northern and Southern Hemispheres; the East - West (E - W) longitudinal distribution study shows that the SAP events are most prolific (best observable) in the 81° to 90° slice in the Eastern and Western Hemispheres. It was found that the SAP activity during this cycle is low compared to previous solar cycles. The present study indicates that during the rising phase of the cycle the number of SAP events are roughly equal in the Northern and Southern Hemispheres. However, activity in the Southern Hemisphere has been dominant since 1999. Our statistical study shows that the N - S asymmetry is more significant then the E - W asymmetry.

  2. Solar wind entry into the high-latitude terrestrial magnetosphere during geomagnetically quiet times.

    PubMed

    Shi, Q Q; Zong, Q-G; Fu, S Y; Dunlop, M W; Pu, Z Y; Parks, G K; Wei, Y; Li, W H; Zhang, H; Nowada, M; Wang, Y B; Sun, W J; Xiao, T; Reme, H; Carr, C; Fazakerley, A N; Lucek, E

    2013-01-01

    An understanding of the transport of solar wind plasma into and throughout the terrestrial magnetosphere is crucial to space science and space weather. For non-active periods, there is little agreement on where and how plasma entry into the magnetosphere might occur. Moreover, behaviour in the high-latitude region behind the magnetospheric cusps, for example, the lobes, is poorly understood, partly because of lack of coverage by previous space missions. Here, using Cluster multi-spacecraft data, we report an unexpected discovery of regions of solar wind entry into the Earth's high-latitude magnetosphere tailward of the cusps. From statistical observational facts and simulation analysis we suggest that these regions are most likely produced by magnetic reconnection at the high-latitude magnetopause, although other processes, such as impulsive penetration, may not be ruled out entirely. We find that the degree of entry can be significant for solar wind transport into the magnetosphere during such quiet times. PMID:23403567

  3. On transpolar arc formation correlated with solar wind entry at high latitude magnetosphere

    NASA Astrophysics Data System (ADS)

    Mailyan, B. G.; Shi, Q.; Maggiolo, R.; Zong, Q.; Fu, S.; Zhang, Y.; Yao, Z.; Sun, W.

    2014-12-01

    Recently, Cluster observations revealed the existence of new regions of solar wind plasma entry at the high latitudes of the Earth's magnetosphere, at the lobes tailward of the cusp region, mostly during periods of northward IMF. Such periods of northward IMF are associated with the presence of transpolar arcs. Observations from Global Ultraviolet Imager (GUVI) instrument onboard TIMED spacecraft are used to investigate a possible link between solar wind entry in the high latitude magnetosphere and the formation of transpolar arcs. Data from IMAGE and DMSP spacecraft are also used to investigate the time evolution and particle characteristics of the transpolar arc.We present a case study of a theta aurora correlated with the solar wind entry. The observations show a simultaneous occurrence of aurora activity at the magnetotail and high latitudes, suggesting two-part structure of the apparent continuous band of the transpolar arc.

  4. Nutation and precession control of the High Energy Solar Physics (HESP) satellite

    NASA Technical Reports Server (NTRS)

    Jayaraman, C. P.; Robertson, B. P.

    1993-01-01

    The High Energy Solar Physics (HESP) spacecraft is an intermediate class satellite proposed by NASA to study solar high-energy phenomena during the next cycle of high solar activity in the 1998 to 2005 time frame. The HESP spacecraft is a spinning satellite which points to the sun with stringent pointing requirements. The natural dynamics of a spinning satellite includes an undesirable effect: nutation, which is due to the presence of disturbances and offsets of the spin axis from the angular momentum vector. The proposed Attitude Control System (ACS) attenuates nutation with reaction wheels. Precessing the spacecraft to track the sun in the north-south and east-west directions is accomplished with the use of torques from magnetic torquer bars. In this paper, the basic dynamics of a spinning spacecraft are derived, control algorithms to meet HESP science requirements are discussed and simulation results to demonstrate feasibility of the ACS concept are presented.

  5. Solar Activity-driven Variability of Instrumental Data Quality

    NASA Astrophysics Data System (ADS)

    Martayan, C.; Smette, A.; Hanuschik, R.; van Der Heyden, P.; Mieske, S.

    2016-06-01

    The unexplained variability of the data quality from Very Large Telescope instruments and the frequency of power cuts have been investigated. Origins for the variability in ambient temperature variations, software, data reduction pipelines and internal to hardware could be discarded. The most probable cause appears to be correlated with the evolution of the cosmic ray rate, and also with solar and terrestrial geomagnetic activity. We report on the consequences of such variability and describe how the observatory infrastructure, instruments and data are affected.

  6. Correlation of Far Ultraviolet Lunar Albedo with Solar Activity

    NASA Technical Reports Server (NTRS)

    Maddox, Will; Spann, James F.; Germany, Glynn

    2004-01-01

    We present a correlative analysis between the variability of the lunar albedo in the far ultraviolet wavelength range (130- 190 nm) and various solar activity indices for a two-week period. We also report lunar albedo measurements in four separate wavelength ranges, corresponding to four filters on the Polar Ultraviolet Imager. To our knowledge this is the first reported long term measurements of the lunar albedo in this wavelength range.

  7. Flate-Plate Solar Array Project: Final report: Volume 4, High-efficiency solar cells

    SciTech Connect

    Leipold, M.; Cheng, L.; Daud, T.; Mokashi, A.; Burger, D.

    1986-10-01

    The High-Efficiency Solar Cells Task was assigned the objective of understanding and developing high-efficiency solar cell devices that would meet the most and performance goals of the FSA Project. The need for research dealing with high efficiency devices was considered important because of the role efficiency plays in reducing the price per watt of generated energy. This document is a summary of the R and D efforts conducted during the period 1982 to 1986 to provide understanding and control of energy conversion losses associated with crystalline-silicon solar cells. New levels of conversion efficiency (greater than 20%) were demonstrated. Major contributions were made both to the understanding and reduction of bulk and surface losses in solar cells. For example, oxides, nitrides, and polysilicon were all shown to be potentially useful surface passivants. Improvements in measurement techniques were made and Auger coefficients and spectral absorption data were obtained for unique types of silicon sheet. New modeling software was developed including a program to optimize a device design based on input characteristics of a cell. Although considerable progress was made in this Task, several elements of research were incomplete at the conclusion of the Project.

  8. Modular High-Energy Systems for Solar Power Satellites

    NASA Technical Reports Server (NTRS)

    Howell, Joe T.; Carrington, Connie K.; Marzwell, Neville I.; Mankins, John C.

    2006-01-01

    Modular High-Energy Systems are Stepping Stones to provide capabilities for energy-rich infrastructure located in space to support a variety of exploration scenarios as well as provide a supplemental source of energy during peak demands to ground grid systems. Abundant renewable energy at lunar or other locations could support propellant production and storage in refueling scenarios that enable affordable exploration. Renewable energy platforms in geosynchronous Earth orbits can collect and transmit power to satellites, or to Earth-surface locations. Energy-rich space technologies also enable the use of electric-powered propulsion systems that could efficiently deliver cargo and exploration facilities to remote locations. A first step to an energy-rich space infrastructure is a 100-kWe class solar-powered platform in Earth orbit. The platform would utilize advanced technologies in solar power collection and generation, power management and distribution, thermal management, electric propulsion, wireless avionics, autonomous in space rendezvous and docking, servicing, and robotic assembly. It would also provide an energy-rich free-flying platform to demonstrate in space a portfolio of technology flight experiments. This paper summary a preliminary design concept for a 100-kWe solar-powered satellite system to demonstrate in-flight a variety of advanced technologies, each as a separate payload. These technologies include, but are not limited to state-of-the-art solar concentrators, highly efficient multi-junction solar cells, integrated thermal management on the arrays, and innovative deployable structure design and packaging to enable the 100-kW satellite feasible to launch on one existing launch vehicle. Higher voltage arrays and power distribution systems (PDS) reduce or eliminate the need for massive power converters, and could enable direct-drive of high-voltage solar electric thrusters.

  9. Development of High Efficiency (14%) Solar Cell Array Module

    NASA Technical Reports Server (NTRS)

    Iles, P. A.; Khemthong, S.; Olah, S.; Sampson, W. J.; Ling, K. S.

    1979-01-01

    High efficiency solar cells required for the low cost modules was developed. The production tooling for the manufacture of the cells and modules was designed. The tooling consisted of: (1) back contact soldering machine; (2) vacuum pickup; (3) antireflective coating tooling; and (4) test fixture.

  10. Non-tracking solar concentrator with a high concentration ratio

    DOEpatents

    Hinterberger, Henry

    1977-01-01

    A nontracking solar concentrator with a high concentration ratio is provided. The concentrator includes a plurality of energy absorbers which communicate with a main header by which absorbed heat is removed. Undesired heat flow of those absorbers not being heated by radiant energy at a particular instant is impeded, improving the efficiency of the concentrator.

  11. How Large Scales Flows May Influence Solar Activity

    NASA Technical Reports Server (NTRS)

    Hathaway, D. H.

    2004-01-01

    Large scale flows within the solar convection zone are the primary drivers of the Sun's magnetic activity cycle and play important roles in shaping the Sun's magnetic field. Differential rotation amplifies the magnetic field through its shearing action and converts poloidal field into toroidal field. Poleward meridional flow near the surface carries magnetic flux that reverses the magnetic poles at about the time of solar maximum. The deeper, equatorward meridional flow can carry magnetic flux back toward the lower latitudes where it erupts through the surface to form tilted active regions that convert toroidal fields into oppositely directed poloidal fields. These axisymmetric flows are themselves driven by large scale convective motions. The effects of the Sun's rotation on convection produce velocity correlations that can maintain both the differential rotation and the meridional circulation. These convective motions can also influence solar activity directly by shaping the magnetic field pattern. While considerable theoretical advances have been made toward understanding these large scale flows, outstanding problems in matching theory to observations still remain.

  12. Dayside Auroral Activity During Solar Maximum and Minimum Periods

    NASA Astrophysics Data System (ADS)

    Rawie, M.; Fasel, G. J.; Flicker, J.; Angelo, A.; Bender, S.; Alyami, M.; Sibeck, D. G.; Sigernes, F.; Lorentzen, D. A.; Green, D.

    2014-12-01

    It is well documented that the dayside auroral oval shifts equatorward when the interplanetary magnetic field (IMF) Bz-component turns southward [Burch, 1973; Akasofu, 1977; Horwitz and Akasofu, 1977; Sandholt et al., 1986, 1988]. During these periods of oval expansion dayside transients are observed to move away from the poleward edge of the auroral oval and drift poleward. These poleward-moving auroral forms are believed to be ionospheric signatures of dayside merging. The dayside auroral oval usually begins to contract when the interplanetary magnetic field turns sharply northward, Bz>0. Eighteen years of meridian scanning photometer (MSP) data from the Kjell Henriksen Observatory in Longyearbyen, Norway are analyzed. During the boreal winter the Sun is several degrees below the horizon. This permits optical observations throughout the daytime period. The MSP Data is selected two hours before and after local noon in Longyearbeyn. Solar wind data (solar wind pressure and speed, along with the IMF Bx, By, Bz components) are collected for each interval and combined with the MSP observations. This data is then separated using solar maximum and minimum periods. Auroral activity (oval expansions and contractions along with the frequency and number of poleward-moving auroral forms) is documented for both solar maximum and minimum periods.

  13. Forecasting the Peak of the Present Solar Activity Cycle

    NASA Astrophysics Data System (ADS)

    Hamid, Rabab; Marzouk, Beshir

    2016-07-01

    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 aa min. 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 RM and spotless event around the preceding minimum gives RM24t = 101.9with rise time Tr = 4.5 Y. For the even cycles RM24e = 108.3 with rise time Tr = 3.9 Y. Based on the average aa min. index for the year of sunspot minimum cycles (13 - 23), we estimate the expected amplitude for cycle 24 to be RMaa = 116.5 for both the total and even cycles. 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 = 146, which are over estimation. Our result indicating a somewhat weaker cycle 24 as compared to cycles 21-23.

  14. SOLAR ROTATION RATE DURING THE CYCLE 24 MINIMUM IN ACTIVITY

    SciTech Connect

    Antia, H. M.; Basu, Sarbani E-mail: sarbani.basu@yale.ed

    2010-09-01

    The minimum of solar cycle 24 is significantly different from most other minima in terms of its duration as well as its abnormally low levels of activity. Using available helioseismic data that cover epochs from the minimum of cycle 23 to now, we study the differences in the nature of the solar rotation between the minima of cycles 23 and 24. We find that there are significant differences between the rotation rates during the two minima. There are differences in the zonal-flow pattern too. We find that the band of fast rotating region close to the equator bifurcated around 2005 and recombined by 2008. This behavior is different from that during the cycle 23 minimum. By autocorrelating the zonal-flow pattern with a time shift, we find that in terms of solar dynamics, solar cycle 23 lasted for a period of 11.7 years, consistent with the result of Howe et al. (2009). The autocorrelation coefficient also confirms that the zonal-flow pattern penetrates through the convection zone.

  15. Active other worlds in the Solar System and beyond

    NASA Astrophysics Data System (ADS)

    Forget, François

    2016-04-01

    Over the past decades, space exploration has moved planetology from the field of astronomy to the disciplines of geosciences. A fleet of spacecrafts have discovered and study tens of worlds in our solar system and beyond. Everywhere, we have been surprised by the diversity and the vigour of the geophysical activity, from volcanic eruptions to plasma waves... Every scientists present at EGU could -and should- be interested in the extraterrestrial processes that are discovered and analyzed elsewhere. In our solar system, a variety of clouds and fluid dynamical phenomena can be studied in six terrestrial atmospheres and on four giant planets. Active glaciers are found on Mars and Pluto. Rivers and lakes have sculpted the surface of Titan and Mars. Sometime, we can even study geophysical activity with no equivalent on our planet: ice caps made of frozen atmosphere that erupt in geysers, hazes formed by organic polymers which can completely shroud a moon, etc. We study these active worlds because we are curious and wish to understand our universe and our origins. However, more than ever, two specific motivations drive solar system geosciences in 2016: Firstly, as we become more and more familiar with the other worlds around us, we can use them to better understand our own planet. Throughout the solar system, we can access to data that are simply not available on the Earth, or study active processes that are subtle on Earth but of greater importance elsewhere, so that we can better understand them. Many geophysical concepts and tools developed for the Earth can also be tested on other planets. For instance the numerical Climate Models used to assess Earth's future climate change are applied to other planets. Much is learned from such experiments. Secondly, the time has come to generalize the fundamental lessons that we have learned from the examples in the solar system (including the Earth) to address the countless scientific questions that are -and will be- raised by

  16. Thermal performance of windows having high solar transmittance

    SciTech Connect

    Rubin, M.; Selkowitz, S.

    1981-07-01

    Antireflected polyester films and low-iron glass sheets have values of solar transmittance that are substantially higher than those of their untreated counterparts. The plastic films utilize coatings to reduce loses due to surface reflectance and the glass is made with low levels of impurities to reduce adsorption within the material itself. The optical and thermal properties of these materials are discussed and the solar and thermal characteristics of windows incorporating high-transmittance glazing layers are derived. Comparisons among these and other types of windows are made on the basis of net energy use for residential buildings in winter.

  17. Investigation of high efficiency GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Olsen, Larry C.; Dunham, Glen; Addis, F. W.; Huber, Dan; Linden, Kurt

    1989-01-01

    Investigations of basic mechanisms which limit the performance of high efficiency GaAs solar cells are discussed. P/N heteroface structures have been fabricated from MOCVD epiwafers. Typical AM1 efficiencies are in the 21 to 22 percent range, with a SERI measurement for one cell being 21.5 percent. The cells are nominally 1.5 x 1.5 cm in size. Studies have involved photoresponse, T-I-V analyses, and interpretation of data in terms of appropriate models to determine key cell parameters. Results of these studies are utilized to determine future approaches for increasing GaAs solar cell efficiencies.

  18. High-flux solar photon processes: Opportunities for applications

    SciTech Connect

    Steinfeld, J.I.; Coy, S.L.; Herzog, H.; Shorter, J.A.; Schlamp, M.; Tester, J.W.; Peters, W.A.

    1992-06-01

    The overall goal of this study was to identify new high-flux solar photon (HFSP) processes that show promise of being feasible and in the national interest. Electric power generation and hazardous waste destruction were excluded from this study at sponsor request. Our overall conclusion is that there is promise for new applications of concentrated solar photons, especially in certain aspects of materials processing and premium materials synthesis. Evaluation of the full potential of these and other possible applications, including opportunities for commercialization, requires further research and testing. 100 refs.

  19. Low latitude F2- and F3- layer variabilities over India: Effects of solar activity and ExB drift

    NASA Astrophysics Data System (ADS)

    Peddapati, PavanChaitanya; Patra, Amit; Balan, Nanan; Vijaya Bhaskara Rao, S.

    In this paper we present and discuss the results on F2 and F3 layers based on ionosonde observations made from low latitude stations in India. We also use ExB drift using daytime 150 km echoes made with the Gadanki MST radar. We present two important aspects of the F2 and F3 layers: (1) The variability of F2 and F3 layer properties during low solar activity period of 2008-2009 and compare them with those observed during the high solar activity period of 2002-2003 (2) The variability of F2 and F3 layer properties with ExB drift values simultaneously observed during low solar activity period. The results show that ionospheric F2 and F3 layers have distinctly different features during high and low solar activities. The critical frequencies of the F2 and F3 layers are 5-6 MHz higher in the high solar activity than those of low solar activity. F2 layer shows stronger semi-annual and solar rotation associated variations during high solar activity than in low solar activity. Occurrence of the F3 layer, however, was quite similar in high and low solar activities except for winter solstice. Simultaneous observations of F2 and F3 layers, and ExB drift made during the low solar activity period clearly suggest that a threshold value of the ExB drift and its time integrated value are important for the formation of the F3 layer. The heights of the F2 and F3 layers linearly increase with ExB drift, indicating the dominant role of zonal electric field in determining the height of the F2 and F3 layers due to the close proximity of Gadanki to the magnetic equator. In order to gain further insight on the role of meridional neutral wind, we study this effect using Sheffield University Plasmasphere Ionosphere Model (SUPIM) by employing the observed ExB drift and F3 layer parameters and meridional neutral wind from Horizontal Wind Model 90 (HWM90).

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

    SciTech Connect

    Shepherd, Simon J.; Zharkov, Sergei I.; Zharkova, Valentina V. E-mail: s.zharkov@hull.ac.uk

    2014-11-01

    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.