Science.gov

Sample records for solar activity

  1. 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.

  2. 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

  3. 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;…

  4. 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)

  5. Geomagnetic response to solar activity.

    NASA Technical Reports Server (NTRS)

    Mead, G. D.

    1972-01-01

    The relationship between solar activity and geomagnetic variations is discussed in the light of spacecraft data obtained during the last decade. The effects of centers of solar activity responsible for producing geomagnetic activity on earth are believed to be transmitted through the solar wind, and there is usually a delay of two or three days before the onset of magnetic activity. Attempts to make a one-to-one correspondence between specific solar events and specific magnetic storms, however, are usually unsuccessful, because of the complex and indirect processes linking the two phenomena. Normally, only statistical tendencies can be shown.

  6. 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.

  7. 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.

  8. Solar active region display system

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

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

  9. 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…

  10. Seismic Forecasting of Solar Activity

    NASA Technical Reports Server (NTRS)

    Braun, Douglas; Lindsey, Charles

    2001-01-01

    We have developed and improved helioseismic imaging techniques of the far-side of the Sun as part of a synoptic monitor of solar activity. In collaboration with the MIDI team at Stanford University we are routinely applying our analysis to images within 24 hours of their acquisition by SOHO. For the first time, real-time seismic maps of large active regions on the Sun's far surface are publicly available. The synoptic images show examples of active regions persisting for one or more solar rotations, as well as those initially detected forming on the solar far side. Until recently, imaging the far surface of the Sun has been essentially blind to active regions more than about 50 degrees from the antipode of disk center. In a paper recently accepted for publication, we have demonstrated how acoustic travel-time perturbations may be mapped over the entire hemisphere of the Sun facing away from the Earth, including the polar regions. In addition to offering significant improvements to ongoing space weather forecasting efforts, the procedure offers the possibility of local seismic monitoring of both the temporal and spatial variations in the acoustic properties of the Sun over the entire far surface.

  11. Decay of Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.; Choudhary, Debi Prasad

    2005-01-01

    We examine the record of sunspot group areas observed over a period of 100 years to determine the rate of decay of solar active regions. We exclude observations of groups when they are more than 60deg in longitude from the central meridian and only include data when at least three days of observations are available following the date of maximum area for a spot group's disk passage. This leaves data for some 24,000 observations of active region decay. We find that the decay rate is a constant 20 microHem/day for spots smaller than about 200 microHem (about the size of a supergranule). This decay rate increases linearly to about 90 microHem/day for spots with areas of 1000 microHem. We find no evidence for significant variations in active region decay from one solar cycle to another. However, we do find that the decay rate is slower at lower latitudes. This gives a slower decay rate during the declining phase of sunspot cycles.

  12. 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.

  13. 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.

  14. 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.

  15. Climate: how unusual is today's solar activity?

    PubMed

    Muscheler, Raimund; Joos, Fortunat; Müller, Simon A; Snowball, Ian

    2005-07-28

    To put global warming into context requires knowledge about past changes in solar activity and the role of the Sun in climate change. Solanki et al. propose that solar activity during recent decades was exceptionally high compared with that over the preceding 8,000 years. However, our extended analysis of the radiocarbon record reveals several periods during past centuries in which the strength of the magnetic field in the solar wind was similar to, or even higher than, that of today.

  16. 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.

  17. 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.

  18. 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.

  19. 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…

  20. Magnetic activity of seismic solar analogs

    NASA Astrophysics Data System (ADS)

    Salabert, D.; García, R. A.; Beck, P. G.

    2016-12-01

    We present our latest results on the solar-stellar connection by studying 18 solar analogs that we identified among the Kepler seismic sample tep{salabert16a}. We measured their magnetic activity properties using observations collected by the Kepler satellite and the ground-based, high-resolution HERMES spectrograph. The photospheric (S{_ph}) and chromospheric (S) magnetic activity proxies of these seismic solar analogs are compared in relation to solar activity. We show that the activity of the Sun is actually comparable to the activity of the seismic solar analogs. Furthermore, we report on the discovery of temporal variability in the acoustic frequencies of the young (1 Gyr-old) solar analog KIC 10644253 with a modulation of about 1.5 years, which agrees with the derived photospheric activity tep{salabert16b}. It could actually be the signature of the short-period modulation, or quasi-biennal oscillation, of its magnetic activity as observed in the Sun and the 1-Gyr-old solar analog HD 30495. In addition, the lithium abundance and the chromospheric activity estimated from HERMES confirms that KIC 10644253 is a young and more active star than the Sun.

  1. 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.

  2. 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.

  3. 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…

  4. About the Solar Activity Rotation Periods

    NASA Astrophysics Data System (ADS)

    Mouradian, Zadig

    2007-03-01

    The purpose of this paper is to evidence, from a statistical point of view, the different periods of solar activity. The well known period is that of 150-160 days, but many others were detected between 9 and 4750 days (length of solar cycle). We tabulated 49 articles revealing 231 periods. In order to explain them, different hypotheses were suggested.

  5. History and Forecast of Solar Activity

    NASA Astrophysics Data System (ADS)

    Mikushina, O. V.; Klimenko, V. V.; Dovgalyuk, V. V.

    From a new reconstruction of the radiocarbon production rate in the atmosphere we obtain a long history of maximum Wolf sunspot numbers. Based on this reconstruction as well as on the history of other indicators of solar activity (10Be, aurora borealis), we derive a long-period trend which together with the results of spectral analysis of maximum Wolf numbers series (1506-1993) form a basis for prediction of solar activity up to 2100. The resulting trigonometric trend points to an essential decrease in solar activity in the coming decades.

  6. Solar activity cycle - History and predictions

    SciTech Connect

    Withbroe, G.L. )

    1989-12-01

    The solar output of short-wavelength radiation, solar wind, and energetic particles depends strongly on the solar cycle. These energy outputs from the sun control conditions in the interplanetary medium and in the terrestrial magnetosphere and upper atmosphere. Consequently, there is substantial interest in the behavior of the solar cycle and its effects. This review briefly discusses historical data on the solar cycle and methods for predicting its further behavior, particularly for the current cycle, which shows signs that it will have moderate to exceptionally high levels of activity. During the next few years, the solar flux of short-wavelength radiation and particles will be more intense than normal, and spacecraft in low earth orbit will reenter earlier than usual. 46 refs.

  7. Sources of solar wind over the solar activity cycle

    PubMed Central

    Poletto, Giannina

    2012-01-01

    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

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. 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...

  13. 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.

  14. 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).

  15. 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

  16. 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.

  17. 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).

  18. Solar Activity Heading for a Maunder Minimum?

    NASA Astrophysics Data System (ADS)

    Schatten, K. H.; Tobiska, W. K.

    2003-05-01

    Long-range (few years to decades) solar activity prediction techniques vary greatly in their methods. They range from examining planetary orbits, to spectral analyses (e.g. Fourier, wavelet and spectral analyses), to artificial intelligence methods, to simply using general statistical techniques. Rather than concentrate on statistical/mathematical/numerical methods, we discuss a class of methods which appears to have a "physical basis." Not only does it have a physical basis, but this basis is rooted in both "basic" physics (dynamo theory), but also solar physics (Babcock dynamo theory). The class we discuss is referred to as "precursor methods," originally developed by Ohl, Brown and Williams and others, using geomagnetic observations. My colleagues and I have developed some understanding for how these methods work and have expanded the prediction methods using "solar dynamo precursor" methods, notably a "SODA" index (SOlar Dynamo Amplitude). These methods are now based upon an understanding of the Sun's dynamo processes- to explain a connection between how the Sun's fields are generated and how the Sun broadcasts its future activity levels to Earth. This has led to better monitoring of the Sun's dynamo fields and is leading to more accurate prediction techniques. Related to the Sun's polar and toroidal magnetic fields, we explain how these methods work, past predictions, the current cycle, and predictions of future of solar activity levels for the next few solar cycles. The surprising result of these long-range predictions is a rapid decline in solar activity, starting with cycle #24. If this trend continues, we may see the Sun heading towards a "Maunder" type of solar activity minimum - an extensive period of reduced levels of solar activity. For the solar physicists, who enjoy studying solar activity, we hope this isn't so, but for NASA, which must place and maintain satellites in low earth orbit (LEO), it may help with reboost problems. Space debris, and other

  19. Solar activity and explosive transient eruptions

    NASA Astrophysics Data System (ADS)

    Ambastha, Ashok

    2016-07-01

    We discuss active and explosive behavior of the Sun observable in a wide range of wavelengths (or energies) and spatio-temporal scales that are not possible for any other star. On the longer time scales, the most notable form of solar activity is the well known so called 11-year solar activity cycle. On the other hand, at shorter time scales of a few minutes to several hours, spectacular explosive transient events, such as, solar flares, prominence eruptions, and coronal mass ejections (CMEs) occur in the outer layers of solar atmosphere. These solar activity cycle and explosive phenomena influence and disturb the space between the Sun and planets. The state of the interplanetary medium, including planetary and terrestrial surroundings, or "the space weather", and its forecasting has important practical consequences. The reliable forecasting of space weather lies in continuously observing of the Sun. We present an account of the recent developments in our understanding of these phenomena using both space-borne and ground-based solar observations.

  20. 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.

  1. 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.

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

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean

    2008-01-01

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

  3. Asymmetric behavior of different solar activity features over solar cycles 20-23

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

    This paper presents the study of normalized north-south asymmetry, cumulative normalized north-south asymmetry and cumulative difference indices of sunspot areas, solar active prominences (at total, low (⩽40°) and high (⩾50°) latitudes) and H α solar flares from 1964 to 2008 spanning the solar cycles 20-23. Three different statistical methods are used to obtain the asymmetric behavior of different solar activity features. Hemispherical distribution of activity features shows the dominance of activities in northern hemisphere for solar cycle 20 and in southern hemisphere for solar cycles 21-23 excluding solar active prominences at high latitudes. Cumulative difference index of solar activity features in each solar cycle is observed at the maximum of the respective solar cycle suggesting a cyclic behavior of approximately one solar cycle length. Asymmetric behavior of all activity features except solar active prominences at high latitudes hints at the long term periodic trend of eight solar cycles. North-south asymmetries of SAP (H) express the specific behavior of solar activity at high solar latitudes and its behavior in long-time scale is distinctly opposite to those of other activity features. Our results show that in most cases the asymmetry is statistically highly significant meaning thereby that the asymmetries are real features in the N-S distribution of solar activity features.

  4. Properties of solar activity and ionosphere for solar cycle 25

    NASA Astrophysics Data System (ADS)

    Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N.

    2016-11-01

    Based on the known forecast of solar cycle 25 amplitude ( Rz max ≈ 50), the first assessments of the shape and amplitude of this cycle in the index of solar activity F10.7 (the magnitude of solar radio flux at the 10.7 cm wavelength) are given. It has been found that ( F10.7)max ≈ 115, which means that it is the lowest solar cycle ever encountered in the history of regular ionospheric measurements. For this reason, many ionospheric parameters for cycle 25, including the F2-layer peak height and critical frequency ( hmF2 and foF2), will be extremely low. For example, at middle latitudes, typical foF2 values will not exceed 8-10 MHz, which makes ionospheric heating ineffective in the area of upper hybrid resonance at frequencies higher than 10 MHz. The density of the atmosphere will also be extremely low, which significantly extends the lifetime of low-orbit satellites. The probability of F-spread will be increased, especially during night hours.

  5. 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)

  6. The solar wind effect on cosmic rays and solar activity

    NASA Technical Reports Server (NTRS)

    Fujimoto, K.; Kojima, H.; Murakami, K.

    1985-01-01

    The relation of cosmic ray intensity to solar wind velocity is investigated, using neutron monitor data from Kiel and Deep River. The analysis shows that the regression coefficient of the average intensity for a time interval to the corresponding average velocity is negative and that the absolute effect increases monotonously with the interval of averaging, tau, that is, from -0.5% per 100km/s for tau = 1 day to -1.1% per 100km/s for tau = 27 days. For tau 27 days the coefficient becomes almost constant independently of the value of tau. The analysis also shows that this tau-dependence of the regression coefficiently is varying with the solar activity.

  7. Stratospheric ozone, solar activity and volcanism

    NASA Astrophysics Data System (ADS)

    Komitov, Boris; Stoychev, Konstantin

    The aim of this study is to investigate the long-term (multiannual) variations of the total ozone content (TOC) on the base of TOMS instrument measurements on the board of Nimbus-7 satellite for the period 1979 -- 1993 AD. The total effects of the solar activity influence over stratosphere ozone has been investigated by using multiple regression analysis. The monthly radio-index F10.7, the cosmic rays neutron flux, the geomagnetic index Ap and the number of GOES x-ray X-class flares have been used as solar or solar-modulated parameters as predictors in the model. The global mean-monthly TOC-parameter has been used as a predictant. It has been found that the coefficient of correlation of the model between TOC and above-mentioned solar and geomagnetic factors is about 0.544. Thus the corresponding factor variance is about 37%. The results calculated by the model have been removed from the original TOC data. It has been found out that during the first 12 years since 1979 the downward trend is predominantly caused by the solar and solar-modulated processes. However during the remaining 3 years after 1990 the slope of the negative trend has been essentially increased. This phenomenon could only be explained by some catastrophic event. Most probably such one is the Pinatubo volcano eruption in June, 1991. An evidence for the possibility that the last one is caused by trigger effect from the extremely high solar flare activity in May -- June 1991, is given.

  8. 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.…

  9. 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.

  10. Dynamics of Minor Solar Activity \

    NASA Astrophysics Data System (ADS)

    Cauzzi, G.; Vial, J. C.; Falciani, R.; Falchi, A.; Smaldone, L. A.

    We present a program for coordinated observations between ground based observatories, mainly NSO/Sacramento Peak, and several instruments onboard SOHO (primarily SUMER). The scientific goal is the study of small activity phenomena, at high spatial and temporal resolution.

  11. Catawba Science Center solar activities. Final report

    SciTech Connect

    1983-01-01

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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Patterns of helicity in solar active regions

    NASA Technical Reports Server (NTRS)

    Pevtsov, Alexei A.; Canfield, Richard C.; Metcalf, Thomas R.

    1994-01-01

    Using 46 vector magnetograms from the Stokes Polarimeter of Mees Solar Observatory (MSO), we studied patterns of local helicity in three diverse solar active regions. From these magnetograms we computed maps of the local helicity parameter alpha = J(sub z)/B(sub z). Although such maps are noisy, we found patterns at the level approximately 2 to 3 sigma(sub J(sub z)), which repeat in successive magnetograms for up to several days. Typically, the alpha maps of any given active region contain identifiable patches with both positive and negative values of alpha. Even within a single sunspot complex, several such alpha patches can often be seen. We followed 68 alpha patches that could be identified on at least two successive alpha maps. We found that the persistence fraction of such patches decrease exponentially, with a characteristic time approximately 27 hr.

  20. What do the solar activity indices represent?

    NASA Astrophysics Data System (ADS)

    Li , K. J.; Kong, D. F.; Liang, H. F.; Feng, W.

    Sunspot number, sunspot area, and radio flux at 10.7 cm are the indices which are most frequently used to describe the long-term solar activity. The data of the daily solar full-disk magnetograms measured at Mount Wilson Observatory from 19 January 1970 to 31 December 2012 are utilized together with the daily observations of the three indices to probe the relationship of the full-disk magnetic activity respectively with the indices. Cross correlation analyses of the daily magnetic field measurements at Mount Wilson observatory are taken with the daily observations of the three indices, and the statistical significance of the difference of the obtained correlation coefficients is investigated. The following results are obtained: (1) The sunspot number should be preferred to represent/reflect the full-disk magnetic activity of the Sun to which the weak magnetic fields (outside of sunspots) mainly contribute, the sunspot area should be recommended to represent the strong magnetic activity of the Sun (in sunspots), and the 10.7 cm radio flux should be preferred to represent the full-disk magnetic activity of the Sun (both the weak and strong magnetic fields) to which the weak magnetic fields mainly contribute. (2) On the other hand, the most recommendable index that could be used to represent/reflect the weak magnetic activity is the 10.7 cm radio flux, the most recommendable index that could be used to represent the strong magnetic activity is the sunspot area, and the most recommendable index that could be used to represent the full-disk magnetic activity of the Sun is the 10.7 cm radio flux. Additionally, the cycle characteristics of the magnetic field strengths on the solar disk are given.

  1. 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.

  2. 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.

  3. 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)

  4. Shuttle program. Solar activity prediction of sunspot numbers, predicted solar radio flux

    NASA Technical Reports Server (NTRS)

    Johnson, G. G.; Newman, S. R.

    1980-01-01

    A solar activity prediction technique for monthly mean sunspot numbers over a period of approximately ten years from February 1979 to January 1989 is presented. This includes the predicted maximum epoch of solar cycle 21, approximately January 1980, and the predicted minimum epoch of solar cycle 22, approximately March 1987. Additionally, the solar radio flux 10.7 centimeter smooth values are included for the same time frame using a smooth 13 month empirical relationship. The incentive for predicting solar activity values is the requirement of solar flux data as input to upper atmosphere density models utilized in mission planning satellite orbital lifetime studies.

  5. 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

  6. 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

  7. 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

  8. Evidence of active region imprints on the solar wind structure

    NASA Technical Reports Server (NTRS)

    Hick, P.; Jackson, B. V.

    1995-01-01

    A common descriptive framework for discussing the solar wind structure in the inner heliosphere uses the global magnetic field as a reference: low density, high velocity solar wind emanates from open magnetic fields, with high density, low speed solar wind flowing outward near the current sheet. In this picture, active regions, underlying closed magnetic field structures in the streamer belt, leave little or no imprint on the solar wind. We present evidence from interplanetary scintillation measurements of the 'disturbance factor' g that active regions play a role in modulating the solar wind and possibly contribute to the solar wind mass output. Hence we find that the traditional view of the solar wind, though useful in understanding many features of solar wind structure, is oversimplified and possibly neglects important aspects of solar wind dynamics

  9. Solar and stellar activity - The theoretical approach

    NASA Astrophysics Data System (ADS)

    Belvedere, G.

    1985-10-01

    The unified approach to understanding solar and stellar activity is examined. Stellar activity observations have stimulated theoretical work, mostly within the framework of the alpha-omega dynamo theory. A number of uncertainties and intrinsic limits in dynamo theory do still exist, and these are discussed together with alternative or complementary suggestions. The relevance is stressed of nonlinear problems in dynamo theory - magnetoconvection, growth and stability of flux tubes against magnetic buoyancy, hydromagnetic global dynamos - to improve the understanding of both small and large scale interaction of rotation, turbulent convection and magnetic fields, and the transition from the linear to the nonlinear regime. Recent dynamo models of stellar activity are critically reviewed regarding the dependence of activity indexes and cycles on rotation rate and spectral type. Open problems to be solved by future work are outlined.

  10. 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.

  11. 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

  12. Periodogram Analysis on Solar Activities Based on El Campo Solar Radar Observation Data

    NASA Astrophysics Data System (ADS)

    Lin, Ye; Zhi-ning, Qu; Min, Wang; Guan-nan, Gao; Jun, Lin; Zhi-chun, Duan

    2016-10-01

    Solar radar can transmit radar waves toward the Sun actively at a specific waveband and receive the reflected waves. By analyzing the echoes, we can obtain the information of motion, magnetic field, and other properties of the solar atmosphere. The El Campo solar radar has done regular observations on the solar corona for 8 years from 1961 to 1969, to trace the variation of solar activities. We have made a periodicity analysis on the obtained data with the Lomb-Scargle periodogram algorithm, and found that there are the 200 day and 540 day periods existed in the variation of the measured solar radar cross section. In addition, we have selected the larger radar cross sections (≥ 20σ⊙) to compare with the Dst indexes. Finally, we have summarized the El Campo solar radar experiment and give a prospect for the future development of the solar radar observation.

  13. 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.

  14. 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)

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Long-term variation of solar activity: recent progress

    NASA Astrophysics Data System (ADS)

    Vaquero, J. M.

    2017-03-01

    The concept of solar activity is a common term nowadays. However, it is not straight-forwardly interpreted and it is ambiguously defined. A review of our knowledge of the long-term behavior of solar activity in the past is presented, as reconstructed using the indirect proxy method (millennial time scale) and the direct historical observations (secular time scale). The latest international efforts to obtain a series of sunspot numbers of the last four centuries are reviewed. Observations of sunspots during the Maunder minimum (1645–1715) are particularly interesting and they show the solar cycle during this period of Grand Minimum of solar activity.

  3. Solar activity affects avian timing of reproduction

    PubMed Central

    Visser, Marcel E.; Sanz, Juan José

    2009-01-01

    Avian timing of reproduction is strongly affected by ambient temperature. Here we show that there is an additional effect of sunspots on laying date, from five long-term population studies of great and blue tits (Parus major and Cyanistes caeruleus), demonstrating for the first time that solar activity not only has an effect on population numbers but that it also affects the timing of animal behaviour. This effect is statistically independent of ambient temperature. In years with few sunspots, birds initiate laying late while they are often early in years with many sunspots. The sunspot effect may be owing to a crucial difference between the method of temperature measurements by meteorological stations (in the shade) and the temperatures experienced by the birds. A better understanding of the impact of all the thermal components of weather on the phenology of ecosystems is essential when predicting their responses to climate change. PMID:19574283

  4. 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.

  5. 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.

  6. 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)

  7. Solar irradiance modulation by active regions from 1969 through 1980

    SciTech Connect

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

    1982-01-01

    The solar irradiance variations resulting from sunspot deficits and facular excesses in emission have been calculated from 1969 through 1980. Agreement appears to exist between our calculations and the major features seen with the Nimbus 7 cavity pyrheliometer and with both the major and minor features detected by The Solar Maximum Mission ACRIM experiment. The 12-year irradiance variations we calculate suggest a larger variance with increased solar activity, and little change in the average irradiance with solar activity. The largest excursions over these 12 years show a 0.4% variation. Removal of the activity influences upon solar irradiance during the numerous rocket experiments observing the solar ''constant'' may allow a better value for this quantity to be determined.

  8. Monthly variations of the Caspian sea level and solar activity.

    NASA Astrophysics Data System (ADS)

    Romanchuk, P. R.; Pasechnik, M. N.

    The connection between 11-year cycle of solar activity and the Caspian sea level is investigated. Seasonal changes of the Caspian sea level and annual variations of the sea level with variations of solar activity are studied. The results of the verifications of the sea level forecasts obtained with application of the rules discovered by the authors are given.

  9. Correlative Aspects of the Solar Electron Neutrino Flux and Solar Activity

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2000-01-01

    Between 1970 and 1994, the Homestake Solar Neutrino Detector obtained 108 observations of the solar electron neutrino flux (less than 0.814 MeV). The "best fit" values derived from these observations suggest an average daily production rate of about 0.485 Ar-37 atom per day, a rate equivalent to about 2.6 SNU (solar neutrino units) or about a factor of 3 below the expected rate from the standard solar model. In order to explain, at least, a portion of this discrepancy, some researchers have speculated that the flux of solar neutrinos is variable, possibly being correlated with various markers of the solar cycle (e.g., sunspot number, the Ap index, etc.). In this paper, using the larger "standard data set," the issue of correlative behavior between solar electron neutrino flux and solar activity is re-examined. The results presented here clearly indicate that no statistically significant association exists between any of the usual markers of solar activity and the solar electron neutrino flux.

  10. 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).

  11. 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.

  12. 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.

  13. 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)

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. A comment on the suspected solar neutrino -- solar activity connection

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    1994-01-01

    Recently, it has been proposed that there exists a highly statistically significant (at greater than or equal to 98% level of confidence) relationship between Ar-37 production rate (namely, solar neutrinos) and the Ap geomagnetic index (namely, solar particles), based on the chi-square goodness-of-fit test and correlation analysis, for the interval 1970-1990. While a relationship between the two parameters, indeed, seems to be discernible, the strength of the relationship has been overstated. Instead of being significant at the afore-mentioned level of confidence, the relationship is found to be significant at only greater than or equal to 95% level of confidence, based on Yates' modification to the chi-square test for 2 x 2 contingency tables. Likewise, while correlation analysis yields a value of r = 0.2691, it is important to note that such a value suggests that only about 7% of the variance can be 'explained' by the inferred correlation and that the remaining 93% of the variance must be attributed to other sources.

  19. 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.

  20. DOE Solar Process Heat Program: FY1991 Solar Process Heat Prefeasibility Studies activity

    SciTech Connect

    Hewett, R.

    1992-11-01

    During fiscal year (FY) 1991, the US Department of Energy (DOE) Solar Process Heat Program implemented a Solar Process Heat Prefeasibility Studies activity. For Program purposes, a prefeasibility study is an engineering assessment that investigates the technical and economic feasibility of a solar system for a specific application for a specific end-user. The study includes an assessment of institutional issues (e.g., financing, availability of insurance, etc.) that impact the feasibility of the proposed solar project. Solar process heat technology covers solar thermal energy systems (utilizing flat plate or concentrating solar Collectors) for water heating, water preheating, cooling/refrigeration, steam generation, ventilation air heating/preheating, etc. for applications in industry, commerce, and government. The studies are selected for funding through a competitive solicitation. For FY 1991, six projects were selected for funding. As of August 31, 1992, three teams had completed their studies. This paper describes the prefeasibility studies activity, presents the results from the study performed by United Solar Technologies, and summarizes the conclusions from the studies that have been completed to date and their implications for the Solar Process Heat Program.

  1. Department of Energy solar process heat program: FY 1991 solar process heat prefeasibility studies activity

    NASA Astrophysics Data System (ADS)

    Hewett, R.

    1992-11-01

    During fiscal year (FY) 1991, the US Department of Energy (DOE) Solar Process Heat Program implemented a Solar Process Heat Prefeasibility Studies activity. For Program purposes, a prefeasibility study is an engineering assessment that investigates the technical and economic feasibility of a solar system for a specific application for a specific end-user. The study includes an assessment of institutional issues (e.g., financing, availability of insurance, etc.) that impact the feasibility of the proposed solar project. Solar process heat technology covers solar thermal energy systems (utilizing flat plate or concentrating solar collectors) for water heating, water preheating, cooling/refrigeration, steam generation, ventilation air heating/preheating, etc., for applications in industry, commerce, and government. The studies are selected for funding through a competitive solicitation. For FY-91, six projects were selected for funding. As of 31 Aug. 1992, three teams had completed their studies. This paper describes the prefeasibility studies activity, presents the results from the study performed by United Solar Technologies, and summarizes the conclusions from the studies that have been completed to date and their implications for the Solar Process Heat Program.

  2. The Nitrate Content of Greenland Ice and Solar Activity

    NASA Astrophysics Data System (ADS)

    Kocharov, G. E.; Kudryavtsev, I. V.; Ogurtsov, M. G.; Sonninen, E.; Jungner, H.

    2000-12-01

    Past solar activity is studied based on analysis of data on the nitrate content of Greenland ice in the period from 1576 1991. Hundred-year (over the entire period) and quasi-five-year (in the middle of the 18th century) variations in the nitrate content are detected. These reflect the secular solar-activity cycle and cyclicity in the flare activity of the Sun.

  3. 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.

  4. 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)

  5. 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)

  6. 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)

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

    NASA Technical Reports Server (NTRS)

    Steinberg, J. L.; Caroubalos, C.

    1976-01-01

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

  8. A new perspective on solar active regions

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  9. Analysis of regression methods for solar activity forecasting

    NASA Technical Reports Server (NTRS)

    Lundquist, C. A.; Vaughan, W. W.

    1979-01-01

    The paper deals with the potential use of the most recent solar data to project trends in the next few years. Assuming that a mode of solar influence on weather can be identified, advantageous use of that knowledge presumably depends on estimating future solar activity. A frequently used technique for solar cycle predictions is a linear regression procedure along the lines formulated by McNish and Lincoln (1949). The paper presents a sensitivity analysis of the behavior of such regression methods relative to the following aspects: cycle minimum, time into cycle, composition of historical data base, and unnormalized vs. normalized solar cycle data. Comparative solar cycle forecasts for several past cycles are presented as to these aspects of the input data. Implications for the current cycle, No. 21, are also given.

  10. The solar activity by wavelet-based multifractal analysis

    NASA Astrophysics Data System (ADS)

    Maruyama, Fumio

    2016-12-01

    The interest in the relation between the solar activity and climate change is increasing. As for the solar activity, a fractal property of the sunspot series was studied by many works. In general, a fractal property was observed in the time series of dynamics of complex systems. The purposes of this study were to investigate the relationship between the sunspot number, solar radio flux at 10.7 cm (F10.7 cm) and total ozone from a view of multifractality. To detect the changes of multifractality, we examined the multifractal analysis on the time series of the solar activity and total ozone indices. The changes of fractality of the sunspot number and F10.7 cm are very similar. When the sunspot number becomes maximum, the fractality of the F10.7 cm changes from multifractality to monofractality. The changes of fractality of the F10.7 cm and the total ozone are very similar. When the sunspot number becomes maximum, the fractality of the total ozone changes from multifractality to monofractality. A change of fractality of the F10.7 cm and total ozone was observed when the solar activity became maximum. The influence of the solar activity on the total ozone was shown by the wavelet coherence, phase and the similarity of the change of fractality. These findings will contribute to the research of the relationship between the solar activity and climate.

  11. On statistical relationship of solar, geomagnetic and human activities.

    PubMed

    Alania, M V; Gil, A; Modzelewska, R

    2004-01-01

    Data of galactic cosmic rays, solar and geomagnetic activities and solar wind parameters on the one side and car accident events (CAE) in Poland on the other have been analyzed in order to reveal the statistical relationships among them for the period of 1990-2001. Cross correlation and cross spectrum of the galactic cosmic ray intensity, the solar wind (SW) velocity, Kp index of geomagnetic activity and CAE in Poland have been carried out. It is shown that in some epochs of the above-mentioned period there is found a reliable relationship between CAE and solar and geomagnetic activities parameters in the range of the different periodicities, especially, 7 days. The periodicity of 7 days revealed in the data of the CAE has the maximum on Friday without any exception for the minimum and maximum epochs of solar activity. However, the periodicity of 7 days is reliably revealed in other parameters characterizing galactic cosmic rays, SW, solar and geomagnetic activities, especially for the minimum epoch of solar activity. The periodicity of 3.5 days found in the series of CAE data more or less can be completely ascribed to the social effects, while the periodicity of 7 days can be ascribed to the social effect or/to the processes on the Sun, in the interplanetary space and in the Earth's magnetosphere and atmosphere.

  12. Automatic Recognition of Solar Features for Developing Data Driven Prediction Models of Solar Activity and Space Weather

    DTIC Science & Technology

    2013-05-01

    Aschwanden, M. J. 2005, Physics of the Solar Corona . An Introduction with Problems and Solutions (2nd edition), ed. Aschwanden, M. J. Balasubramaniam, K...AFRL-OSR-VA-TR-2013-0020 Automatic Recognition of Solar Features for Developing Data Driven Prediction Models of Solar Activity...Automatic Recognition of Solar Features for Developing Data Driven Prediction Models of Solar Activity and Space Weather 5a. CONTRACT NUMBER FA9550-09

  13. Solar Thermal Propulsion Investigation Activities in NAL

    NASA Astrophysics Data System (ADS)

    Sahara, Hironori; Shimizu, Morio

    2004-03-01

    We successfully developed the ultra-light single shell paraboloidal concentrators made of a sheet of aluminized or silvered polymer membrane, formed via plastic deformation due to stress relaxation under high temperature condition by means of Straight Formation Method. Furthermore, we improved the precision of the concentrators by taking the elastic deformation of residual stress into consideration, and obtained the best concentration performance equivalent to a highly precise paraboloidal glass mirror. In solar concentration, the diameter of solar focal image via the single shell polymer concentrator is almost equal to that via the glass mirror and they are twice as large as that of the theoretical. The ultra-light single shell polymer concentrators are very useful for the concentrator in solar thermal propulsion system and solar power station in particular, and also promising item for beamed energy propulsion.

  14. Solar wind control of auroral zone geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Clauer, C. R.; Mcpherron, R. L.; Searls, C.; Kivelson, M. G.

    1981-01-01

    Solar wind magnetosphere energy coupling functions are analyzed using linear prediction filtering with 2.5 minute data. The relationship of auroral zone geomagnetic activity to solar wind power input functions are examined, and a least squares prediction filter, or impulse response function is designed from the data. Computed impulse response functions are observed to have characteristics of a low pass filter with time delay. The AL index is found well related to solar wind energy functions, although the AU index shows a poor relationship. High frequency variations of auroral indices and substorm expansions are not predictable with solar wind information alone, suggesting influence by internal magnetospheric processes. Finally, the epsilon parameter shows a poorer relationship with auroral geomagnetic activity than a power parameter, having a VBs solar wind dependency.

  15. Observed Helicity of Active Regions in Solar Cycle 21

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Pevtsov, A. A.; Blehm, Z.; Smith, J. E.; Six, Frank (Technical Monitor)

    2003-01-01

    We report the results of a study of helicity in solar active regions during the peak of activity in solar cycle 21 from observations with the Marshall Space Flight Center's solar vector magnetograph. Using the force-free parameter alpha as the proxy for helicity, we calculated an average value of alpha for each of 60 active regions from a total of 449 vector magnetograms that were obtained during the period 1980 March to November. The signs of these average values of alpha were correlated with the latitude of the active regions to test the hemispheric rule of helicity that has been proposed for solar magnetic fields: negative helicity predominant in northern latitudes, positive in the southern ones. We have found that of the 60 regions that were observed, 30 obey the hemispheric rule and 30 do not.

  16. 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.

  17. 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.

  18. Development of a complex of activity in the solar corona

    NASA Technical Reports Server (NTRS)

    Howard, R.; Svestka, Z.

    1977-01-01

    Using Skylab observations of soft solar X-rays, the development of a complex of activity in the solar corona during its whole lifetime of seven solar rotations is studied. The basic components of the activity complex were determined to be permanently interconnected through sets of magnetic field lines, which suggests similar connections also below the photosphere. The visibility of individual loops in these connections, however, was greatly variable and typically shorter than one day. Each brightening of a coronal loop in X-rays seems to be related to a variation in the photospheric magnetic field near its footprint.

  19. Investigation of X-ray and optical solar flare activities during solar cycles 22 and 23

    NASA Astrophysics Data System (ADS)

    Akimov, L. A.; Belkina, I. L.; Bushueva, T. P.

    2003-02-01

    Daily X-ray flare indices (XFI) for the interval from January 1986 till June 2002 were calculated. The XFI behaviour during solar cycles 22 and 23 was studied. We compare the daily XFI with the daily optical flare indices (OFI) and with the International Relative Sunspot Numbers. The energy emitted by X-ray flares during 77 months of solar cycle 22 is shown to be about five times larger than the analogous value for the present solar cycle. We revealed statistically significant maxima in power spectra of the XFI and OFI. They correspond to periods of 25.5, 36.5, 73, 116, and 150d which presumably are appropriate to characteristic frequencies of the solar flare activity. A hypothesis on an possible effect of Mercury's variable electric charge on the origin of solar flares is proposed and corresponding estimates were made.

  20. 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.

  1. 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.

  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. Recent contributions to solar activity theory

    NASA Astrophysics Data System (ADS)

    Schuessler, M.

    1980-10-01

    The current status of the theory of photospheric magnetic fields and the solar cycle theory is reviewed. Some new observations concerning the photospheric magnetic fields, the bright X-ray spots, and the ratio of the umbra radius to the penumbra radius are discussed, and their importance for these theories and their further development is examined.

  4. New improved reconstruction of solar activity over 3 millennia: Evidence for distinct solar dynamo modes

    NASA Astrophysics Data System (ADS)

    Usoskin, Ilya; Kovaltsov, Gennady; Hulot, Gauthier.; Gallet, Yves; Roth, Raphael; Licht, Alexis; Joos, Fortunat; Th, E.; Khokhlov, A.; Kovaltsov, Gennady A.

    The solar magnetic dynamo can operate in distinct modes - a main general mode, a Grand minimum mode corresponding to an inactive Sun, and a possible Grand maximum mode corresponding to an unusually active Sun, as e.g., observed recently. The reality of such mode separation has recently been the subject of much debate, with different theoretical speculations discussed. Here we present the first adjustment-free physical reconstruction of solar activity over the past three millennia, using the latest carbon cycle, (14) C production and archeomagnetic field models. This new improved reconstruction shows that the solar dynamo process indeed switches between different modes, either corresponding to different regimes of the dynamo or to changes in the driving parameters. These results provide important constraints for both dynamo models of Sun-like stars and investigations of possible solar influence on Earth’s climate.

  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.

  6. 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.

  7. Solar Transients Disturbing the Mid Latitude Ionosphere during the High Solar Activity

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Shivangi; Khan, Parvaiz A.; Atulkar, Roshni; Malvi, Bhupendra; Mansoori, Azad Ahmad; Purohit, P. K.

    2016-10-01

    We investigate the effect of solar transients on the mid latitude ionosphere during the high solar activity period of solar cycle 23 i.e 2003 and 2004. A mid latitude station, Guangzhou (23.1N, 113.4E) was selected to carry out the investigation. The ionospheric behaviour at the selected station is characterized by considering the critical frequency of F2 layer (foF2) obtained by using the ground based Ionosonde observations. Then we selected two types of solar transients viz. solar flares and Coronal Mass Ejections (CMEs). To quantify the effect of solar flares we have considered the X-ray flux (1-8 Å) and EUV flux (26-34nm). Similarly to quantify the effect of CMEs, we have considered the geomagnetic storms, because during high solar activity the geomagnetic storms are caused by CMEs. From our analysis we conclude that during the geomagnetic storms the value of foF2 decreases as compared to quiet days thereby showing a negative effect. On the contrary we found that during solar flares there is sudden and intense increase in foF2. We also performed a correlation analysis to access the magnitude of association between changes in flux values and peak values of Dst during flares and storms with the corresponding changes and peak values of foF2. We found that a strong correlation exists between the enhancements/decrements in foF2 and enhancements in flux values and Dst. We conclude, while geomagnetic activity suppresses ionospheric activity the flares enhance the same.

  8. 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.

  9. THE MAGNETIC CLASSIFICATION OF SOLAR ACTIVE REGIONS 1992–2015

    SciTech Connect

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

    2016-03-20

    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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Study of solar activity and cosmic ray modulation during solar cycle 24 in comparison to previous solar cycle

    NASA Astrophysics Data System (ADS)

    Mishra, V. K.; Mishra, A. P.

    2016-12-01

    Based on the monthly data of sunspot numbers (SSN), sunspot area of full disc (SSA) and cosmic ray intensity (CRI) observed by neutron monitors (NM) located at Oulu (Cut off Rigidity = 0.8 GV) and Moscow (Cut off Rigidity = 2.3 GV), the trend of solar activity variation and cosmic ray modulation has been studied during the cycles 23 & 24. The SSN have maintained its minimum level exceptionally for a long period (July 2008-Aug. 2009) of time. The intensity of galactic cosmic rays measured by ground based detectors is the highest ever recorded by Oulu NM since April 1964 during the recent solar minimum. Furthermore, the maximum value of SSN is found to be very low in the present cycle in comparison to previous solar cycles (19-23). The correlation coefficient between SSN and CRI without and with time-lag as well as regression analysis during the solar cycle 24 (Jan. 2008-Dec. 2015) has been estimated and compared with previous solar cycle. Based on the maximum value of correlation coefficient, the time-lag during present solar cycle is found to be 4 and 10 months for both the stations, while it is 13-14 months during cycle 23. The behaviour of running cross correlation function has also been examined during present solar cycle and it is found that it attains its maximum value -0.8 to -0.9 for a long duration in comparison to previous cycles. The variation of SSN and SSA has also been compared and found that they are highly correlated to each other (r > .92) for both the cycles. In the light of exceptional behaviour of solar cycle 24, the trend of cosmic ray modulation has been discussed and compared with earlier cycles.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Development of Solar Activity Cycle 24: Some Comments

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    Our forecast for the development phase of the solar cycle 23 turned out to be right on the mark; one of the very few to have acquired this status out of nearly 40 forecasts made for cycle 23. This is the first time in the 400 year history of the sunspot observations that a forecast was made for a solar cycle, it was defended against a severe peer criticism and came out true. We review the details of our actual forcast and how they fared as the events unfolded during cycle 23. We then consider the present status of the solar wind, the geomagnetic planetary indices, and the recovery of the galactic cosmic rays from cycle 23 modulation. Next, we draw inferences as to what to expect for the development phase of solar cycle 24. We are aware that several forecasts have already been made for the development of solar cycle 24 activity. They cover all possible scenarios, ranging from the most active to the quietest ever cycle. Clearly, some of these forecasts are unlikely to materialize. We discuss emerging details of the physical link between the observations and the workings of the solar dynamo.

  1. Engineering principles and concepts for active solar systems

    NASA Astrophysics Data System (ADS)

    Hunn, B. D.; Carlisle, N.; Franta, G.; Kolar, W.

    1987-07-01

    This publication is a much refined and updated version of a solar design handbook originally prepared in 1978 to accompany a series of week-long courses conducted in support of the Solar Federal Buildings Program. The 1978 material was published in 1981 as the Solar Design Workbook (SERI/SP-62-308). This current document represents the culmination of an eight-year effort to compile a comprehensive state-of-the-art reference and instructional tool for practicing design professionals, architects, and engineers. It is intended to cover all phases of the design and installation of active solar energy systems for buildings. Although it contains many design guidelines, the emphasis is on providing sufficient knowledge of how these systems work to allow an engineer or architect to make well-informed decisions. It is aimed primarily at commercial building applications, but most of the material is also applicable to residential buildings.

  2. 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.

  3. 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.

  4. 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.

  5. Multi-scale statistical analysis of coronal solar activity

    DOE PAGES

    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.

  6. 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.

  7. 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.

  8. SOLAR SPECTRAL IRRADIANCE, SOLAR ACTIVITY, AND THE NEAR-ULTRA-VIOLET

    SciTech Connect

    Fontenla, J. M.; Stancil, P. C.; Landi, E. E-mail: stancil@physast.uga.edu

    2015-08-20

    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.

  9. Solar Active Longitudes from Kodaikanal White-light Digitized Data

    NASA Astrophysics Data System (ADS)

    Mandal, Sudip; Chatterjee, Subhamoy; Banerjee, Dipankar

    2017-01-01

    The study of solar active longitudes has generated great interest in recent years. In this work we have used a unique, continuous sunspot data series obtained from the Kodaikanal observatory and revisited the problem. An analysis of the data shows a persistent presence of active longitudes during the whole 90 years of data. We compared two well-studied analysis methods and presented their results. The separation between the two most active longitudes is found be roughly 180° for the majority of time. Additionally, we also find a comparatively weaker presence of separations at 90° and 270°. The migration pattern of these active longitudes as revealed by our data is found to be consistent with the solar differential rotation curve. We also study the periodicities in the active longitudes and found two dominant periods of ≈1.3 and ≈2.2 years. These periods, also found in other solar proxies, indicate their relation with the global solar dynamo mechanism.

  10. Periodogram analysis of sunspot numbers and the relation with solar activities

    NASA Technical Reports Server (NTRS)

    Hady, Ahmed A.

    1995-01-01

    The time series of average monthly sunspot numbers during 1900-1992 is studied by using power spectral analysis. This prediction method is used to study the sunspot periodicities relations between its, and with the other periodicities by solar activities. There are periodicities (between few days and 5 years) overwhelm on the mean solar cycle. ( 11 year cycle). These periodicities have the same relation with variations of solar constant and solar radiation reaching the Earth's atmosphere in the last solar cycle. These periods are related to the solar magnetic activity and to the modulation of solar features due to solar rotation.

  11. Indonesia Stratosphere and Troposphere Response to Solar Activity Variations

    NASA Astrophysics Data System (ADS)

    Sinambela, Wilson; Muh, La Ode; Musafar, K.; Sutastio, Heri

    2000-10-01

    Tropospheric and stratospheric response of Indonesia to the solar activity was analyzed based on the stratospheric total ozone concentrations above Watukosek station (07,6 deg S, 112,5 deg E) from 1979 to 1992, and tropospheric temperature at tropopause geopotential height, 500 mBar, 700 mbar above Cengkareng - Jakarta station (06 deg) 07 min 37 sec S, 106 deg 39 min 28 sec E) from 1986 to 1992, and ground surface air temperature above Polonia Median (03 deg 34 sec N, 98 deg 41 min E) and Kemayoran - Jakarta station (06 deg 09 min S 106 deg 51 min E) from 1979 - 1989. By using the moving average analysis of monthly average this tropospheric and stratospheric variable, were found that the behavior of the time series of the stratospheric ozone concentration, tropospheric temperature at geopotential height tropopause, 500 mBar, 700 mBar and ground surface air temperature above Indonesia showed a tendency to vary with a period of about 22 - 32 months. This is so - called " Quasi Biennial" (Q B 0). The behavior of the relative sunspot numbers and / or F 10,7 Cm solar radio flux as the measure of the solar activity also showed a tendency to vary Quasi - Biennially with a period about 27 - 30 months which was superimposed to the eleven - year solar cycle variations. The source of the variations was predicted from the inside of the sun, since the experiment showed that the neutrino flux from the sun varies with a period almost equal to the Quasi - Biennial variations of the solar activity. The Quasi - Biennial variations of the solar activity seems produce a similar variations on the earth atmospheric phenomena such as the stratospheric total ozone concentrations, mean tropospheric temperature at geopotential tropopause height, 500 mBar, 700 mBar, and mean ground surface air temperature above Indonesia.

  12. The reconstruction of solar activity in the context of solar dynamo modeling

    NASA Astrophysics Data System (ADS)

    Sokoloff, D.

    2017-01-01

    We discuss problems of interpretation of sunspot data for use in solar dynamo modelling. The variety of the current sunspot reconstructions of archival data creates substantial difficulties for such an endeavour. We suggest a possible strategy to avoid these problems. The point is that we have to accept the possibility of several solar activity reconstructions that are contradictory in detail, and have to compare several possible reconstructions with dynamo models. The point is that a given reconstruction may not cover all the time interval of interest because this reconstruction requires information unavailable at earlier or later times.

  13. 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

  14. E region electric field dependence of the solar activity

    NASA Astrophysics Data System (ADS)

    Denardini, C. M.; Moro, J.; Resende, L. C. A.; Chen, S. S.; Schuch, N. J.; Costa, J. E. R.

    2015-10-01

    We have being studying the zonal and vertical E region electric field components inferred from the Doppler shifts of type 2 echoes (gradient drift irregularities) detected with the 50 MHz backscatter coherent radar set at São Luis, Brazil (SLZ, 2.3°S, 44.2°W) during the solar cycle 24. In this report we present the dependence of the vertical and zonal components of this electric field with the solar activity, based on the solar flux F10.7. For this study we consider the geomagnetically quiet days only (Kp ≤ 3+). A magnetic field-aligned-integrated conductivity model was developed for proving the conductivities, using the IRI-2007, the MISIS-2000, and the IGRF-11 models as input parameters for ionosphere, neutral atmosphere, and Earth magnetic field, respectively. The ion-neutron collision frequencies of all the species are combined through the momentum transfer collision frequency equation. The mean zonal component of the electric field, which normally ranged from 0.19 to 0.35 mV/m between the 8 and 18 h (LT) in the Brazilian sector, show a small dependency with the solar activity. Whereas the mean vertical component of the electric field, which normally ranges from 4.65 to 10.12 mV/m, highlights the more pronounced dependency of the solar flux.

  15. Statistical analysis of solar energetic particle events and related solar activity

    NASA Astrophysics Data System (ADS)

    Dierckxsens, Mark; Patsou, Ioanna; Tziotziou, Kostas; Marsh, Michael; Lygeros, Nik; Crosby, Norma; Dalla, Silvia; Malandraki, Olga

    2013-04-01

    The FP7 COMESEP (COronal Mass Ejections and Solar Energetic Particles: forecasting the space weather impact) project is developing tools for forecasting geomagnetic storms and solar energetic particle (SEP) radiation storms. Here we present preliminary results on a statistical analysis of SEP events and their parent solar activity during Solar Cycle 23. The work aims to identify correlations between solar events and SEP events relevant for space weather, as well as to quantify SEP event probabilities for use within the COMESEP alert system. The data sample covers the SOHO era and is based on the SEPEM reference event list [http://dev.sepem.oma.be/]. Events are subdivided if separate enhancements are observed in higher energy channels as defined for the list of Cane et al (2010). Energetic Storm Particle (ESP) enhancements during these events are identified by associating ESP-like increases in the proton channels with shocks detected in ACE and WIND data. Their contribution has been estimated and subtracted from the proton fluxes. Relationships are investigated between solar flare parameters such as X-ray intensity and heliographic location on the one hand, and the probability of occurrence and strength of energetic proton flux increases on the other hand. The same exercise is performed using the velocity and width of coronal mass ejections to examine their SEP productiveness. Relationships between solar event characteristics and SEP event spectral indices and fluences are also studied, as well as enhancements in heavy ion fluxes measured by the SIS instrument on board the ACE spacecraft during the same event periods. This work has received funding from the European Commission FP7 Project COMESEP (263252).

  16. 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.

  17. 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

  18. 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.

  19. Relationship of The Tropical Cyclogenesis With Solar and Magnetospheric Activities

    NASA Astrophysics Data System (ADS)

    Vishnevsky, O.; Pankov, V.; Erokhine, N.

    Formation of tropical cyclones is a badly studied period in their life cycle even though there are many papers dedicated to analysis of influence of different parameters upon cyclones occurrence frequency (see e.g., Gray W.M.). Present paper is dedicated to study of correlation of solar and magnetospheric activity with the appearance of tropi- cal cyclones in north-west region of Pacific ocean. Study of correlation was performed by using both classical statistical methods (including maximum entropy method) and quite modern ones, for example multifractal analysis. Information about Wolf's num- bers and cyclogenesis intensity in period of 1944-2000 was received from different Internet databases. It was shown that power spectra maximums of Wolf's numbers and appeared tropical cyclones ones corresponds to 11-year period; solar activity and cyclogenesis processes intensity are in antiphase; maximum of mutual correlation co- efficient ( 0.8) between Wolf's numbers and cyclogenesis intensity is in South-China sea. There is a relation of multifractal characteristics calculated for both time series with the mutual correlation function that is another indicator of correlation between tropical cyclogenesis and solar-magnetospheric activity. So, there is the correlation between solar-magnetospheric activity and tropical cyclone intensity in this region. Possible physical mechanisms of such correlation including anomalous precipitations charged particles from the Earth radiation belts and wind intensity amplification in the troposphere are discussed.

  20. Relationship of The Tropical Cyclogenesis With Solar and Magnetospheric Activities

    NASA Astrophysics Data System (ADS)

    Vishnevsky, O. V.; Pankov, V. M.; Erokhine, N. S.

    Formation of tropical cyclones is a badly studied period in their life cycle even though there are many papers dedicated to analysis of influence of different parameters upon cyclones occurrence frequency (see e.g., Gray W.M.). Present paper is dedicated to study of correlation of solar and magnetospheric activity with the appearance of tropical cyclones in north-west region of Pacific ocean. Study of correlation was performed by using both classical statistical methods (including maximum entropy method) and quite modern ones, for example multifractal analysis. Information about Wolf's numbers and cyclogenesis intensity in period of 1944-2000 was received from different Internet databases. It was shown that power spectra maximums of Wolf's numbers and appeared tropical cyclones ones corresponds to 11-year period; solar activity and cyclogenesis processes intensity are in antiphase; maximum of mutual correlation coefficient (~ 0.8) between Wolf's numbers and cyclogenesis intensity is in South-China sea. There is a relation of multifractal characteristics calculated for both time series with the mutual correlation function that is another indicator of correlation between tropical cyclogenesis and solar-magnetospheric activity. So, there is the correlation between solar-magnetospheric activity and tropical cyclone intensity in this region. Possible physical mechanisms of such correlation including anomalous precipitations charged particles from the Earth radiation belts and wind intensity amplification in the troposphere are discussed.

  1. Stratospheric condensation nuclei variations may relate to solar activity

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Rosen, J. M.

    1982-01-01

    Observations of increases of stratospheric condensation nuclei suggest a photo-initiated sulphuric acid vapour formation process in spring in polar regions. It is proposed that the sulphuric acid rapidly forms condensation nuclei through attachment to negatively charged multi-ion complexes and that the process may be modulated through variations in solar activity.

  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. Intermittency of the Solar Magnetic Field and Solar Magnetic Activity Cycle

    NASA Astrophysics Data System (ADS)

    Shibalova, A. S.; Obridko, V. N.; Sokoloff, D. D.

    2017-03-01

    Small-scale solar magnetic fields demonstrate features of fractal intermittent behavior, which requires quantification. For this purpose we investigate how the observational estimate of the solar magnetic flux density B depends on resolution D in order to obtain the scaling ln BD = - k ln D +a in a reasonably wide range. The quantity k demonstrates cyclic variations typical of a solar activity cycle. In addition, k depends on the magnetic flux density, i.e. the ratio of the magnetic flux to the area over which the flux is calculated, at a given instant. The quantity a demonstrates some cyclic variation, but it is much weaker than in the case of k. The scaling obtained generalizes previous scalings found for the particular cycle phases. The scaling is typical of fractal structures. In our opinion, the results obtained trace small-scale action in the solar convective zone and its coexistence with the conventional large-scale solar dynamo based on differential rotation and mirror-asymmetric convection.

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

    NASA Astrophysics Data System (ADS)

    Ishitsuka, J. K.

    2006-11-01

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

  5. An astro-comb calibrated solar telescope to study solar activity and search for the radial velocity signature of Venus

    NASA Astrophysics Data System (ADS)

    Phillips, David; HARPS-N Collaboration

    2017-01-01

    We recently demonstrated sub-m/s sensitivity in measuring the radial velocity (RV) between the Earth and Sun using a simple solar telescope feeding the HARPS-N spectrograph at the Italian National Telescope, which is calibrated with a laser frequency comb calibrator optimized for calibrating high resolution spectrographs and referred to as an astro-comb. We are using the solar telescope to characterize the effects of stellar (solar) RV jitter due to activity on the solar surface over the course of many hours every clear day. With the help of solar satellites such as the Solar Dynamics Observatory (SDO), we are characterizing the correlation between observed RV and detailed imaging of the solar photosphere. We plan to use these tools to mitigate the effects of stellar jitter with the goal of the detection of Venus from its solar RV signature, thus showing the potential of the RV technique to detect true Earth-twins.

  6. 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).

  7. Connection between solar activity cycles and grand minima generation

    NASA Astrophysics Data System (ADS)

    Vecchio, A.; Lepreti, F.; Laurenza, M.; Alberti, T.; Carbone, V.

    2017-03-01

    Aims: The revised dataset of sunspot and group numbers (released by WDC-SILSO) and the sunspot number reconstruction based on dendrochronologically dated radiocarbon concentrations have been analyzed to provide a deeper characterization of the solar activity main periodicities and to investigate the role of the Gleissberg and Suess cycles in the grand minima occurrence. Methods: Empirical mode decomposition (EMD) has been used to isolate the time behavior of the different solar activity periodicities. A general consistency among the results from all the analyzed datasets verifies the reliability of the EMD approach. Results: The analysis on the revised sunspot data indicates that the highest energy content is associated with the Schwabe cycle. In correspondence with the grand minima (Maunder and Dalton), the frequency of this cycle changes to longer timescales of 14 yr. The Gleissberg and Suess cycles, with timescales of 60-120 yr and 200-300 yr, respectively, represent the most energetic contribution to sunspot number reconstruction records and are both found to be characterized by multiple scales of oscillation. The grand minima generation and the origin of the two expected distinct types of grand minima, Maunder and longer Spörer-like, are naturally explained through the EMD approach. We found that the grand minima sequence is produced by the coupling between Gleissberg and Suess cycles, the latter being responsible for the most intense and longest Spörer-like minima (with typical duration longer than 80 yr). Finally, we identified a non-solar component, characterized by a very long scale oscillation of 7000 yr, and the Hallstatt cycle ( 2000 yr), likely due to the solar activity. Conclusions: These results provide new observational constraints on the properties of the solar cycle periodicities, the grand minima generation, and thus the long-term behavior of the solar dynamo.

  8. 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.

  9. MSFC solar activity predictions for satellite orbital lifetime estimation

    NASA Technical Reports Server (NTRS)

    Fuler, H. C.; Lundquist, C. A.; Vaughan, W. W.

    1979-01-01

    The procedure to predict solar activity indexes for use in upper atmosphere density models is given together with an example of the performance. The prediction procedure employs a least square linear regression model to generate the predicted smoothed vinculum R sub 13 and geomagnetic vinculum A sub p(13) values. Linear regression equations are then employed to compute corresponding vinculum F sub 10.7(13) solar flux values from the predicted vinculum R sub 13 values. The output is issued principally for satellite orbital lifetime estimations.

  10. Periodicities in the north-south asymmetry of solar activity

    NASA Astrophysics Data System (ADS)

    Vizoso, G.; Ballester, J. L.

    1989-09-01

    A Blackman-Tukey power spectrum is performed on the values of the north-south asymmetry in the sudden disappearance of solar prominences, and the results are reported. The findings confirm the proposed existence of a periodicity of around 11 years and fails to confirm another short periodicity of around 2.3 years. The results of the power spectrum performed using values of the flare number and flare index north-south asymmetry provide a significant peak of 3.1-3.2 years. This short periodicity could be related to those found by Ramanuja Rao (1973) in several indices of solar activity.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    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.

  13. Photospheric Magnetic Free Energy Density of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Zhang, Hongqi

    2016-12-01

    We present the photospheric energy density of magnetic fields in two solar active regions (one of them recurrent) inferred from observational vector magnetograms, and compare it with other available differently defined energy parameters of magnetic fields in the photosphere. We analyze the magnetic fields in Active Regions NOAA 6580-6619-6659 and 11158. The quantity 1/4π{B}n\\cdot{B}p is an important energy parameter that reflects the contribution of magnetic shear to the difference between the potential (Bp) and the non-potential magnetic field (Bn), and also the contribution to the free magnetic energy near the magnetic neutral lines in the active regions. It is found that the photospheric mean magnetic energy density shows clear changes before the powerful solar flares in Active Region NOAA 11158, which is consistent with the change in magnetic fields in the flaring lower atmosphere.

  14. Using the SDO Atmospheric Imaging Assembly to Study Solar Activity

    NASA Astrophysics Data System (ADS)

    Lemen, James

    2014-01-01

    The Atmospheric Imaging Assembly (AIA) is one of the instruments on board NASA’s flagship Solar Dynamics Observatory (SDO) mission that was launched in February 2010. AIA achieves 1.5 arcsec spatial resolution of the entire solar corona with 12-second temporal resolution in seven extreme ultraviolet (EUV) band passes centered on specific lines: Fe XVIII (94 Å), Fe VIII, XXI (131 Å), Fe IX (171 Å), Fe XII, XXIV (193 Å), Fe XIV (211 Å), He II (304 Å) and Fe XVI (335 Å) one band pass observes C IV (near 1600 Å). In the past 3 years AIA has produced over 77M images and 1,200 Tbytes of data that have challenged and clarified our understanding of the solar corona, specifically how the solar magnetic field drives coronal evolution on various scales. Multi-temperature, low-noise, full-Sun observations have captured solar eruptions and flares, coronal field oscillations (in loops and filaments), fast-mode waves (up to 2,000 km/s), plasma instabilities, and a rare view of comet interactions with the corona. Comparison with data from other instruments, such as SDO EUV Variability Experiment (EVE), and with numerical models, provides the ability to develop a comprehensive understanding of solar activity and evolution. And the comparison of the information-rich spatial content of the AIA observations with EVE spectra is instructive for similar studies of stellar targets. The NASA heliophysics open-data policy enables wide-scale participation by the international community. As the time base of AIA observations and magnetic data obtained from the companion SDO Helioseismic and Magnetic Imager (HMI) increases to a good fraction of the solar dynamo cycle time scale, we anticipate that the value of the SDO data will be similarly magnified. We present highlights that have been gleaned from this already exceptional mission. http://sdowww.lmsal.com

  15. No link between the solar activity cycle and the diameter

    NASA Astrophysics Data System (ADS)

    Dame, L.; Cugnet, D.

    We do not understand the physical mechanisms responsible for the solar irradiance cycle. Measurements of small variations in the solar diameter could have been a critical probe of the Sun 's interior stratification, telling us how and where the solar luminosity is gated or stored. We have reanalyzed the 7 years of filtregrams data (150 000 photograms and magnetograms) of the SOHO/MDI experiment. We used the maximum possible sampling compatible with full frame recording, carefully avoiding any suspicious filtregram. Going further than the previous analysis of 2 years of data by Emilio et al. (Ap. J. 543,1007, 2000), we better corrected for changes in optical aberrations and, along Turmon et al. (Ap. J., 568, 396, 2002), we reduced radius measurement errors by identifying active regions and avoiding radius measurements herein. We found that, within the limit of our noise level uncertainties (2 mas), the solar diameter could be constant over the half cycle investigated. Our results confirm the recent reanalysis of the 7 years of MDI data made by Antia (Ap. J. 590, 567, 2003), with a completely different method since using the ultra-precise frequency variation of the f-modes (fundamental modes linked to the diameter). He found (carefully removing the yearly Earth induced variations and avoiding the SOHO data gap of 1999) that the diameter is constant over the half solar cycle (radius variation are less than 0.6 km, 0.8 mas - nothing over noise level). Along Antia, we can conclude that: "If a careful analysis is performed, then it turns out that there is no evidence for any variation in the solar radius." There were no theoretical reasons for large solar radius variations and there is no observational evidence for them with consistent space observations. If changes exit, they are to be very small.

  16. Static and Dynamic Modeling of a Solar Active Region

    NASA Astrophysics Data System (ADS)

    Warren, Harry P.; Winebarger, Amy R.

    2007-09-01

    Recent hydrostatic simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high-temperature emission observed at soft X-ray wavelengths using static heating models. These static models, however, cannot account for the lower temperature emission. In addition, there is ample observational evidence that the solar corona is highly variable, indicating a significant role for dynamical processes in coronal heating. Because they are computationally demanding, full hydrodynamic simulations of solar active regions have not been considered previously. In this paper we make first application of an impulsive heating model to the simulation of an entire active region, AR 8156 observed on 1998 February 16. We model this region by coupling potential field extrapolations to full solutions of the time-dependent hydrodynamic loop equations. To make the problem more tractable we begin with a static heating model that reproduces the emission observed in four different Yohkoh Soft X-Ray Telescope (SXT) filters and consider impulsive heating scenarios that yield time-averaged SXT intensities that are consistent with the static case. We find that it is possible to reproduce the total observed soft X-ray emission in all of the SXT filters with a dynamical heating model, indicating that nanoflare heating is consistent with the observational properties of the high-temperature solar corona. At EUV wavelengths the simulated emission shows more coronal loops, but the agreement between the simulation and the observation is still not acceptable.

  17. 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.

  18. Background magnetic fields during last three cycles of solar activity

    NASA Astrophysics Data System (ADS)

    Andryeyeva, O. A.; Stepanian, N. N.

    2008-07-01

    This paper describes our studies of evolution of the solar magnetic field with different sign and field strength in the range from -100 G to 100 G. The structure and evolution of large-scale magnetic fields on the Sun during the last 3 cycles of solar activity is investigated using magnetograph data from the Kitt Peak Solar Observatory. This analysis reveals two groups of the large-scale magnetic fields evolving differently during the cycles. The first group is represented by relatively weak background fields, and is best observed in the range of 3-10 Gauss. The second group is represented by stronger fields of 75-100 Gauss. The spatial and temporal properties of these groups are described and compared with the total magnetic flux. It is shown that the anomalous behaviour of the total flux during the last cycle can be found only in the second group

  19. Overview of solar detoxification activities in the United States

    SciTech Connect

    Mehos, M; Williams, T; Turchi, C

    1994-10-01

    The U.S. Department of Energy, through the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories, has been investigating a process that uses solar energy to destroy hazardous wastes in air and water. The process, photocatalytic oxidation, uses ultraviolet light in conjunction with the semiconductor titanium dioxide to generate highly reactive hydroxyl radicals. Early research and development activities have demonstrated that photocatalysis may be cost effective for some applications. The Department of Energy is currently working to establish a commercial industry that uses solar energy to destroy hazardous wastes in air, water, and soil. To achieve this objective, NREL and Sandia are bringing together environmental firms, solar manufacturers, and organizations that have waste or remediation problems.

  20. Photometric observations of the energetics of small solar active regions

    SciTech Connect

    Lawrence, J.K.; Chapman, G.A. )

    1990-10-01

    The energetics of small solar active regions was investigated using for the analysis the photometric solar images taken from July 29 to September 6, 1984 with the San Fernando Observatory's 28-cm vacuum telescope, vacuum spectroheliograph, and dual 512 element Reticon linear diode arrays. Ten small newly formed regions were observed, whose entire sunspot evolution apparently occurred within the observed disk crossing. Seven of these showed a net energy excess of a few times 10 to the 33th ergs during this time. These results are discussed in connection with the 0.1 percent decline in solar irradiance observed by the SMM/ACRIM and Nimbus 7/ERB radiometers between 1980 and 1986. 35 refs.

  1. Depth of origin of solar active regions

    NASA Technical Reports Server (NTRS)

    Parker, E. N.

    1984-01-01

    Observations show that the individual bipolar magnetic regions on the sun remain confined during their decay phase, with much of the magnetic field pulling back under the surface, in reverse of the earlier emergence. This suggests that the magnetic field is held on a short rein by subsurface forces, for otherwise the region would decay entirely by dispersing across the face of the sun. With the simple assumption that the fields at the surface are controlled from well-defined anchor points at a depth h, it is possible to relate the length l of the bipolar region at the surface to the depth h, with h about equal to l. The observed dimensions l about equal to 100,000 km for normal active regions, and l about equal to 10,000 km for the ephemeral active regions, indicate comparable depths of origin. More detailed observational studies of the active regions may be expected to shed further light on the problem.

  2. Data Assimilation Approach for Forecast of Solar Activity Cycles

    NASA Astrophysics Data System (ADS)

    Kitiashvili, Irina N.

    2016-11-01

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

  3. Study of seismic activity during the ascending and descending phases of solar activity

    NASA Astrophysics Data System (ADS)

    Sukma, Indriani; Abidin, Zamri Zainal

    2016-12-01

    The study of the solar cycle and geomagnetic index associated with the seismic activity from the year 1901 to the end of 2015 has been done for an area that covers the majority of China and its bordering countries. Data of sunspot number, solar wind speed, daily storm time index and earthquake number are collected from NOAA, NASA, WDC, OMNI and USGS databases and websites. The earthquakes are classified into small (M < 5) and large (M ≥ 5) magnitudes (in Richter scale). We investigated the variation of earthquake activities with the geomagnetic storm index due to the solar wind. We focused on their variation in the ascending and descending phases of solar cycle. From our study, we conclude that there is a correlation between the phases' geomagnetic index and solar wind speed. We have also suggested that there is a certain degree of correlation between solar activity and seismicity in these phases. For every solar cycle, we find that there is a trend for earthquakes to occur in greater numbers during the descending phase. This can be explained by the increment in the solar wind speed and geomagnetic storm index during this phase.

  4. Magnetic modulation of solar luminosity by photospheric activity

    SciTech Connect

    Foukal, P.; Lean, J.

    1988-05-01

    The behavior of slow changes in solar irradiance S is studied using measurements obtained with radiometers on the SMM and Nimbus 7 spacecraft. The general downtrend in the radiometer readings is examined by removing the influence of sunspot blocking and comparing the residual irradiance variations with changes in facular and network radiation as indicated by the He I 10830 and CaK indices. The time-integrated sunspot and facular contributions to irradiance variation and its implications for active region energetics are considered. The magnetic activity modulation of S over solar cycle 21 from daily data on sunspot blocking and the He I index are simulated, and this simulated irradiance variation is compared to radiometry since 1978. Other recent evidence for an irradiance modulation by magnetic activity is discussed. 38 references.

  5. Magnetic modulation of solar luminosity by photospheric activity

    NASA Technical Reports Server (NTRS)

    Foukal, P.; Lean, J.

    1988-01-01

    The behavior of slow changes in solar irradiance S is studied using measurements obtained with radiometers on the SMM and Nimbus 7 spacecraft. The general downtrend in the radiometer readings is examined by removing the influence of sunspot blocking and comparing the residual irradiance variations with changes in facular and network radiation as indicated by the He I 10830 and CaK indices. The time-integrated sunspot and facular contributions to irradiance variation and its implications for active region energetics are considered. The magnetic activity modulation of S over solar cycle 21 from daily data on sunspot blocking and the He I index are simulated, and this simulated irradiance variation is compared to radiometry since 1978. Other recent evidence for an irradiance modulation by magnetic activity is discussed.

  6. Density and Temperature Measurements in a Solar Active Region

    NASA Astrophysics Data System (ADS)

    Warren, Harry P.; Winebarger, Amy R.

    2003-10-01

    We present electron density and temperature measurements from an active region observed above the limb with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer on the Solar and Heliospheric Observatory. Density-sensitive line ratios from Si VIII and S X indicate densities greater than 108 cm-3 as high as 200" (or 145 Mm) above the limb. At these heights, static, uniformly heated loop models predict densities close to 107 cm-3. Differential emission measure analysis shows that the observed plasma is nearly isothermal with a mean temperature of about 1.5 MK and a dispersion of about 0.2 MK. Both the differential emission measure and the Si XI/Si VIII line ratios indicate only small variations in the temperature at the heights observed. These measurements confirm recent observations from the Transition Region and Coronal Explorer of ``overdense'' plasma at temperatures near 1 MK in solar active regions. Time-dependent hydrodynamic simulations suggest that impulsive heating models can account for the large densities, but they have a difficult time reproducing the narrow range of observed temperatures. The observations of overdense, nearly isothermal plasma in the solar corona provide a significant challenge to theories of coronal heating.

  7. 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.

  8. 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.

  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. 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.

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

    PubMed

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

    2016-09-01

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

  12. 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.

  13. Can we understand time scales of solar activity?

    NASA Astrophysics Data System (ADS)

    Kremliovsky, M. N.

    1994-05-01

    The dynamo theory of the solar cycle faces numerous difficulties in regard to an explanation of the observed behavior of sunspot activity. In particular, there is an essential irregularity in the sequence of 11(22)-year cycles. In this paper we want to show how the complicated long-term evolution of solar activity can be understood within the framework of a simple model demonstrating low-dimensional chaotic behavior. According to this description we are able to give a definition for the periods of low activity (Global Minima), to describe how the transition to (from) a Global Minimum occurs and to show the role of the 11(22)-year cycle and its phase catastrophe. The explanations of the origin of the Gleissberg cycle and thousand-year variations of solar activity are given. In summary, the independence of the proposed scenario from the particular choice of model is shown. Thus one can formulate dynamics in the language of generalized instabilities which can aid the search for the underlying physical processes.

  14. Solar activity influence on air temperature regimes in caves

    NASA Astrophysics Data System (ADS)

    Stoeva, Penka; Mikhalev, Alexander; Stoev, Alexey

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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Automatic Recognition of Solar Features for Developing Data Driven Prediction Models of Solar Activity and Space Weather

    DTIC Science & Technology

    2012-07-06

    Ephemeral Brightening,” 2nd ATST – East Workshop In Solar Physics: Magnetic Fields From The Photosphere To The Corona , Washington D.C., Mar 2012. [6...AFRL-RV-PS- AFRL-RV-PS- TR-2012-0133 TR-2012-0133 AUTOMATIC RECOGNITION OF SOLAR FEATURES FOR DEVELOPING DATA DRIVEN PREDICTION MODELS OF... SOLAR ACTIVITY AND SPACE WEATHER Jason Jackiewicz New Mexico State University Department of Astronomy PO Box 30001, MSC 4500 Las

  1. Solar activity and climate change during the 1750 A.D. solar minimum

    NASA Astrophysics Data System (ADS)

    Bard, Edouard; Baroni, Mélanie; Aster Team

    2015-04-01

    The number of sunspots and other characteristics have been widely used to reconstruct the solar activity beyond the last three decades of accurate satellite measurements. It has also been possible to reconstruct the long-term solar behavior by measuring the abundance on Earth of cosmogenic nuclides such as carbon 14 and beryllium 10. These isotopes are formed by the interaction of galactic cosmic rays with atmospheric molecules. Accelerator mass spectrometry is used to measure the abundance of these isotopes in natural archives such as polar ice (for 10Be), tree rings and corals (for 14C). Over the last millennium, the solar activity has been dominated by alternating active and quiet periods, such as the Maunder Minimum, which occurred between 1645 and 1715 A.D. The climate forcing of this solar variability is the subject of intense research, both because the exact scaling in terms of irradiance is still a matter of debate and because other solar variations may have played a role in amplifying the climatic response. Indeed, the past few decades of accurate solar measurements do not include conditions equivalent to an extended solar minimum. A further difficulty of the analysis lies in the presence of other climate forcings during the last millennium, which are superimposed on the solar variations. Finally, the inherent precision of paleotemperature proxies are close to the signal amplitude retrieved from various paleoclimate archives covering the last millennium. Recent model-data comparisons for the last millennium have led to the conclusion that the solar forcing during this period was minor in comparison to volcanic eruptions and greenhouse gas concentrations (e.g. Schurer et al. 2013 J. Clim., 2014 Nat. Geo.). In order to separate the different forcings, it is useful to focus on a temperature change in phase with a well-documented solar minimum so as to maximize the response to this astronomical forcing. This is the approach followed by Wagner et al. (2005 Clim

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

    NASA Technical Reports Server (NTRS)

    Willson, Robert F.

    1991-01-01

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

  3. Twist of Magnetic Fields in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Zhang, Hongqi; Bao, Shudong; Kuzanyan, Kirill M.

    2002-05-01

    We study the twist properties of photospheric magnetic fields in solar active regions using magnetographic data on 422 active regions obtained at the Huairou Solar Observing Station in 1988 1997. We calculate the mean twist (force-free field αf) of the active regions and compare it with the mean current-helicity density of these same active regions, h c =B ∥·(∇×B)∥. The latitude and longitude distributions and time dependence of these quantities is analyzed. These parameters represent two different tracers of the α effect in dynamo theory, so we might expect them to possess similar properties. However, apart from differences in their definitions, they also display differences associated with the technique used to recalculate the magnetographic data and with their different physical meanings. The distributions of the mean αf and h c both show hemispherical asymmetry—negative (positive) values in the northern (southern) hemisphere—although this tendency is stronger for h c. One reason for these differences may be the averaging procedure, when twists of opposite sign in regions with weak fields make a small contribution to the mean current-helicity density. Such transequatorial regularity is in agreement with the expectations of dynamo theory. In some active regions, the average αf and h c do not obey this transequatorial rule. As a whole, the mean twist of the magnetic fields αf of active regions does not vary significantly with the solar cycle. Active regions that do not follow the general behavior for αf do not show any appreciable tendency to cluster at certain longitudes, in contrast to results for h c noted in previous studies. We analyze similarities and differences in the distributions of these two quantities. We conclude that using only one of these tracers, such as αf, to search for signatures of the α effect can have disadvantages, which should be taken into account in future studies.

  4. 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

  5. NASDA activities in space solar power system research, development and applications

    NASA Technical Reports Server (NTRS)

    Matsuda, Sumio; Yamamoto, Yasunari; Uesugi, Masato

    1993-01-01

    NASDA activities in solar cell research, development, and applications are described. First, current technologies for space solar cells such as Si, GaAs, and InP are reviewed. Second, future space solar cell technologies intended to be used on satellites of 21st century are discussed. Next, the flight data of solar cell monitor on ETS-V is shown. Finally, establishing the universal space solar cell calibration system is proposed.

  6. A new simple dynamo model for solar activity cycle

    NASA Astrophysics Data System (ADS)

    Yokoi, Nobumitsu; Schmitt, Dieter

    2015-04-01

    The solar magnetic activity cycle has been investigated in an elaborated manner with several types of dynamo models [1]. In most of the current mean-field approaches, the inhomogeneity of the large-scale flow is treated as an essential ingredient in the mean magnetic field equation whereas it is completely neglected in the turbulence equation. In this work, a new simple model for the solar activity cycle is proposed. The present model differs from the previous ones mainly in two points. First, in addition to the helicity coefficient α, we consider a term related to the cross helicity, which represents the effect of the inhomogeneous mean flow, in the turbulent electromotive force [2, 3]. Second, this transport coefficient (γ) is not treated as an adjustable parameter, but the evolution equation for γ is simultaneously solved. The basic scenario for the solar activity cycle in this approach is as follows: The toroidal field is induced by the toroidal rotation in mediation by the turbulent cross helicity. Then due to the α or helicity effect, the poloidal field is generated from the toroidal field. The poloidal field induced by the α effect produces a turbulent cross helicity whose sign is opposite to the original one (negative cross-helicity production). The cross helicity with this opposite sign induces a reversed toroidal field. Results of the eigenvalue analysis of the model equations are shown, which confirm the above scenario. References [1] Charbonneau, Living Rev. Solar Phys. 7, 3 (2010). [2] Yoshizawa, A. Phys. Fluids B 2, 1589 (1990). [3] Yokoi, N. Geophys. Astrophys. Fluid Dyn. 107, 114 (2013).

  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. Correlations of magnetospheric ion composition with geomagnetic and solar activity

    SciTech Connect

    Young, D.T.; Balsiger, H.; Geiss, J.

    1982-11-01

    A large ion composition data set consisting of 1-month averages has been assembled for the energy per charge range 0.9--15.9 keV/e. It includes 48 months of data taken by the Ion Composition Experiments on the ESA/GEOS 1 and 2 satellites at or near geostationary orbit. Data were obtained during the rising and maximum phases of the current solar cycle from May 1977 through November 1981 inclusive. Five ion species are routinely identifiable: H/sup +/, He/sup + +/, He/sup +/, O/sup + +/, and O/sup +/, above a limiting density approx.10/sup -3/ ions cm/sup -3/. Ion densities exhibit a number of very striking statistical correlations with one another and with both Kp and solar EUV as measured by F/sub 10.7/. One principal result is that increases in the densities of magnetospheric He/sup +/, O/sup + +/, and O/sup +/ are observed that are apparently due entirely to increased solar EUV fluxes associated with the ring phase of the current solar cycle. There is a marked rise in O/sup +/ density by a factor of approx.8 with increasing geomagnetic activity, but no correpsonding increase in either He/sup +/ or O/sup + +/ and only a small increase in H/sup +/. The He/sup + +//H/sup +/ ratio is found to be remarkably constant at roughly-equal0.01. Contrary to ion density results, little or no variation is found in mean energy. These observations are interpreted in terms of the composition and dynamics of two sources of magnetospheric plasma: the solar wind and the high-latitude topside ionosphere.

  9. Solar EUV Variability from FISM and SDO/EVE During Solar Minimum, Active, and Flaring Time Periods

    NASA Technical Reports Server (NTRS)

    Chamberlin, Phillip C.

    2011-01-01

    The Living With a Star (LWS) Focus Science Team has identified three periods of different solar activity levels for which they will be determining the Earth's Ionosphere and Thermosphere response. Not only will the team be comparing individual models (e.g. FLIP, T1MEGCM, GLOW) outcome driven by the various levels of solar activity, but the models themselves will also be compared. These models all rely on the input solar EUV (0.1 -190 nm) irradiance to drive the variability. The Flare Irradiance Spectral Model (FISM) and the EUV Variability Experiment (EVE) onboard provide the Solar Dynamics Observatory (SDO) provide the most accurate quantification of these irradiances. Presented and discussed are how much the solar EUV irradiance changes during these three scenarios, both as a function of activity and wavelength.

  10. A Practical Application of Microcomputers to Control an Active Solar System.

    ERIC Educational Resources Information Center

    Goldman, David S.; Warren, William

    1984-01-01

    Describes the design and implementation of a microcomputer-based model active solar heating system. Includes discussions of: (1) the active solar components (solar collector, heat exchanger, pump, and fan necessary to provide forced air heating); (2) software components; and (3) hardware components (in the form of sensors and actuators). (JN)

  11. Exploiting the Magnetic Origin of Solar Activity in Forecasting Thermospheric Density Variations

    DTIC Science & Technology

    2014-09-01

    Exploiting the Magnetic Origin of Solar Activity in Forecasting Thermospheric Density Variations Harry Warren Naval Research Laboratory, Space...Science Division, Washington, DC John Emmert Naval Research Laboratory, Space Science Division, Washington, DC Abstract A detailed understanding of solar ...drag. Current operational models rely on forecasts of proxies for solar activity based on autoregression. The forecasts from these models generally

  12. Triennial Report 2006-2009. Commission 10: Solar Activity

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.

    2008-01-01

    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 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.

  13. 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.

  14. The Role of Magnetic Reconnection in Solar Activity

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro; DeVore, C. R.

    2008-01-01

    The central challenge in solar/heliospheric physics is to understand how the emergence and transport of magnetic flux at the photosphere drives the structure and dynamics that we observe in the corona and heliosphere. This presentation focuses on the role of magnetic reconnection in determining solar/heliospheric activity. We demonstrate that two generic properties of the photospheric magnetic and velocity fields are responsible for the ubiquitous reconnection in the corona. First, the photospheric velocities are complex, which leads to the injection of energy and helicity into the coronal magnetic fields and to the efficient, formation of small-scale structure. Second, the flux distribution at the photosphere is multi-polar, which implies that topological discontinuities and, consequently, current sheets, must be present in the coronal magnetic field. We: present numerical simulations showing that photospherically-driven reconnection is responsible for the heating and dynamics of coronal plasma, and for the topology of the coronal/heliospheric magnetic field.

  15. Non-Stationary Effects and Cross Correlations in Solar Activity

    NASA Astrophysics Data System (ADS)

    Nefedyev, Yuri; Panischev, Oleg; Demin, Sergey

    2016-07-01

    In this paper within the framework of the Flicker-Noise Spectroscopy (FNS) we consider the dynamic properties of the solar activity by analyzing the Zurich sunspot numbers. As is well-known astrophysics objects are the non-stationary open systems, whose evolution are the quite individual and have the alternation effects. The main difference of FNS compared to other related methods is the separation of the original signal reflecting the dynamics of solar activity into three frequency bands: system-specific "resonances" and their interferential contributions at lower frequencies, chaotic "random walk" ("irregularity-jump") components at larger frequencies, and chaotic "irregularity-spike" (inertial) components in the highest frequency range. Specific parameters corresponding to each of the bands are introduced and calculated. These irregularities as well as specific resonance frequencies are considered as the information carriers on every hierarchical level of the evolution of a complex natural system with intermittent behavior, consecutive alternation of rapid chaotic changes in the values of dynamic variables on small time intervals with small variations of the values on longer time intervals ("laminar" phases). The jump and spike irregularities are described by power spectra and difference moments (transient structural functions) of the second order. FNS allows revealing the most crucial points of the solar activity dynamics by means of "spikiness" factor. It is shown that this variable behaves as the predictor of crucial changes of the sunspot number dynamics, particularly when the number comes up to maximum value. The change of averaging interval allows revealing the non-stationary effects depending by 11-year cycle and by inside processes in a cycle. To consider the cross correlations between the different variables of solar activity we use the Zurich sunspot numbers and the sequence of corona's radiation energy. The FNS-approach allows extracting the

  16. DISTRIBUTION OF ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Török, T.; Titov, V. S.; Mikić, Z.; Leake, J. E.; Archontis, V.; Linton, M. G.; Dalmasse, K.; Aulanier, G.; Kliem, B.

    2014-02-10

    There has been a long-standing debate on the question of whether or not electric currents in solar active regions are neutralized. That is, whether or not the main (or direct) coronal currents connecting the active region polarities are surrounded by shielding (or return) currents of equal total value and opposite direction. Both theory and observations are not yet fully conclusive regarding this question, and numerical simulations have, surprisingly, barely been used to address it. Here we quantify the evolution of electric currents during the formation of a bipolar active region by considering a three-dimensional magnetohydrodynamic simulation of the emergence of a sub-photospheric, current-neutralized magnetic flux rope into the solar atmosphere. We find that a strong deviation from current neutralization develops simultaneously with the onset of significant flux emergence into the corona, accompanied by the development of substantial magnetic shear along the active region's polarity inversion line. After the region has formed and flux emergence has ceased, the strong magnetic fields in the region's center are connected solely by direct currents, and the total direct current is several times larger than the total return current. These results suggest that active regions, the main sources of coronal mass ejections and flares, are born with substantial net currents, in agreement with recent observations. Furthermore, they support eruption models that employ pre-eruption magnetic fields containing such currents.

  17. Comparison of Solar Active Region Complexity Andgeomagnetic Activity from 1996 TO 2014

    NASA Astrophysics Data System (ADS)

    Tanskanen, E. I.; Nikbakhsh, S.; Perez-Suarez, D.; Hackman, T.

    2015-12-01

    We have studied the influence of magnetic complexity of solar Active Regions (ARs)on geomagnetic activity from 1996 to 2014. Sunspots are visual indicators of ARswhere the solar magnetic field is disturbed. We have used International, American,Space Environment Service Center (SESC) and Space Weather Prediction Center(SWPC) sunspot numbers to examine ARs. Major manifestations of solar magneticactivity, such as flares and Coronal Mass Ejections (CMEs), are associated withARs. For this study we chose the Mount Wilson scheme. It classifies ARs in terms oftheir magnetic topology from the least complex (?) to the most complex one ( ?).Several cases have been found where the more complex structures produce strongerflares and CMEs than the less complex ones. We have a list of identified substormsavailable with different phases and their durations. This will be compared to ourmagnetic complexity data to analyse the effects of active region magnetic complexityto the magnetic activity on the vicinity of the Earth.

  18. Magnetic Properties of Solar Active Regions That Govern Large Solar Flares and Eruptions

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim of understanding the magnetic properties that govern such flares and eruptions, we systematically survey all flare events with Geostationary Orbiting Environmental Satellite levels of ≥M5.0 within 45° from disk center between 2010 May and 2016 April. These criteria lead to a total of 51 flares from 29 ARs, for which we analyze the observational data obtained by the Solar Dynamics Observatory. More than 80% of the 29 ARs are found to exhibit δ-sunspots, and at least three ARs violate Hale’s polarity rule. The flare durations are approximately proportional to the distance between the two flare ribbons, to the total magnetic flux inside the ribbons, and to the ribbon area. From our study, one of the parameters that clearly determine whether a given flare event is CME-eruptive or not is the ribbon area normalized by the sunspot area, which may indicate that the structural relationship between the flaring region and the entire AR controls CME productivity. AR characterization shows that even X-class events do not require δ-sunspots or strong-field, high-gradient polarity inversion lines. An investigation of historical observational data suggests the possibility that the largest solar ARs, with magnetic flux of 2 × 1023 Mx, might be able to produce “superflares” with energies of the order of 1034 erg. The proportionality between the flare durations and magnetic energies is consistent with stellar flare observations, suggesting a common physical background for solar and stellar flares.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  1. Continuous plasma outflows from the edge of a solar active region as a possible source of solar wind.

    PubMed

    Sakao, Taro; Kano, Ryouhei; Narukage, Noriyuki; Kotoku, Jun'ichi; Bando, Takamasa; Deluca, Edward E; Lundquist, Loraine L; Tsuneta, Saku; Harra, Louise K; Katsukawa, Yukio; Kubo, Masahito; Hara, Hirohisa; Matsuzaki, Keiichi; Shimojo, Masumi; Bookbinder, Jay A; Golub, Leon; Korreck, Kelly E; Su, Yingna; Shibasaki, Kiyoto; Shimizu, Toshifumi; Nakatani, Ichiro

    2007-12-07

    The Sun continuously expels a huge amount of ionized material into interplanetary space as the solar wind. Despite its influence on the heliospheric environment, the origin of the solar wind has yet to be well identified. In this paper, we report Hinode X-ray Telescope observations of a solar active region. At the edge of the active region, located adjacent to a coronal hole, a pattern of continuous outflow of soft-x-ray-emitting plasmas was identified emanating along apparently open magnetic field lines and into the upper corona. Estimates of temperature and density for the outflowing plasmas suggest a mass loss rate that amounts to approximately 1/4 of the total mass loss rate of the solar wind. These outflows may be indicative of one of the solar wind sources at the Sun.

  2. Determination of the Rotation Periods of Solar Active Longitudes

    NASA Astrophysics Data System (ADS)

    Plyusnina, L. A.

    2010-02-01

    There are two types of active longitudes (ALs) in terms of the distribution of sunspot areas: long-lived and intra-cyclic ALs. The rotation period of the long-lived ALs has been determined by a new method in this paper. The method is based on the property of ALs to be maintained over several cycles of solar activity. The daily values of sunspot areas for 1878 - 2005 are analyzed. It is shown that the AL positions remain almost constant over a period of about ten cycles, from cycle 13 to cycle 22. The rotation period was found to be 27.965 days during this period. The dispersion in AL positions is about 26° from cycle to cycle, which is half of the dispersion observed in the Carrington system. The ALs in the growth phase of the activity cycle are more stable and pronounced. The excess in solar activity in the ALs over adjacent longitudinal intervals is about 12 - 14%. It is shown that only one long-lived AL can be observed at one time on the Sun, as a rule.

  3. Argonne Solar Energy Program annual report. Summary of solar program activities for fiscal year 1979

    SciTech Connect

    1980-06-01

    The R and D work done at Argonne National Laboratory on solar energy technologies during the period October 1, 1978 to September 30, 1979 is described. Technical areas included in the ANL solar program are solar energy collection, heating and cooling, thermal energy storage, ocean thermal energy conversion, photovoltaics, biomass conversion, satellite power systems, and solar liquid-metal MHD power systems.

  4. Evaluation of long term solar activity effects on GPS derived TEC

    NASA Astrophysics Data System (ADS)

    Mansoori, Azad A.; Khan, Parvaiz A.; Ahmad, Rafi; Atulkar, Roshni; M, Aslam A.; Bhardwaj, Shivangi; Malvi, Bhupendra; Purohit, P. K.; Gwal, A. K.

    2016-10-01

    The solar activity hence the solar radiance follows a long term periodic variability with eleven years periodicity, known as solar cycle. This drives the long term variability of the ionosphere. In the present problem we investigate the long term behaviour of the ionosphere with the eleven year cyclic solar activity. Under the present study we characterize the ionospheric variability by Total Electron Content (TEC) using measurements made by Global Positioning System (GPS) and solar cycle variability by various solar activity indices. We make use of five solar activity indices viz. sunspot number (Rz), solar radio Flux (F10.7 cm), EUV Flux (26-34 nm), flare index and CME occurrences. The long term variability of these solar activity indices were then compared and correlated with the variability of ionospheric TEC, at a mid latitude station, Usuda (36.13N, 138.36E), of Japan, during the solar cycle 23 and ascending phase of cycle 24. From our study, we found that long term changes in the ionospheric TEC vary synchronously with corresponding changes in the solar activity indices. The correlation analysis shows that all the solar activity indices exhibit a very strong correlation with TEC (R =0.76 -0.99). Moreover the correlation between the two is stronger in the descending phase of the solar cycle. The correlation is found to be remarkably strongest during the deep minimum of the solar cycle 24 i.e. between 2007- 2009. Also we noticed a hysteresis effect exists with solar radio flux (F10.7 cm) and solar EUV flux (26-34 nm). This effect is absent with other parameters.

  5. THE ORIGIN OF NET ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS

    SciTech Connect

    Dalmasse, K.; Kliem, B.; Török, T.

    2015-09-01

    There is a recurring question in solar physics regarding whether or not electric currents are neutralized in active regions (ARs). This question was recently revisited using three-dimensional (3D) magnetohydrodynamic (MHD) numerical simulations of magnetic flux emergence into the solar atmosphere. Such simulations showed that flux emergence can generate a substantial net current in ARs. Other sources of AR currents are photospheric horizontal flows. Our aim is to determine the conditions for the occurrence of net versus neutralized currents with this second mechanism. Using 3D MHD simulations, we systematically impose line-tied, quasi-static, photospheric twisting and shearing motions to a bipolar potential magnetic field. We find that such flows: (1) produce both direct and return currents, (2) induce very weak compression currents—not observed in 2.5D—in the ambient field present in the close vicinity of the current-carrying field, and (3) can generate force-free magnetic fields with a net current. We demonstrate that neutralized currents are in general produced only in the absence of magnetic shear at the photospheric polarity inversion line—a special condition that is rarely observed. We conclude that  photospheric flows, as magnetic flux emergence, can build up net currents in the solar atmosphere, in agreement with recent observations. These results thus provide support for eruption models based on pre-eruption magnetic fields that possess a net coronal current.

  6. The midlatitude ionospheric response to fluctuations in solar activity under low geomagnetic activity conditions

    NASA Technical Reports Server (NTRS)

    Bendito, J. L.

    1973-01-01

    The ionospheric response, which is the sensitivity and delay of the electron content to the 270 day fluctuations of solar radiation has been theoretically analyzed. In the context of the present work the sensitivity is defined as the magnitude of the electron content fluctuation for a given change in solar flux, and the delay is defined as the timeshift of the response of the electron content to fluctuations in solar flux. Both the model in which the action of neutral winds on the F-2 layer is disregarded and that in which the wind effect is included as part of a positive feedback mechanism, are studied. It is shown that the neutral winds play a dominant role in the mentioned ionospheric response. The computed delays decrease with increasing solar activity in both models.

  7. Effects of Solar Activities on the Transient Luminous Events

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Williams, E.; Chou, J.; Lee, L.; Huang, S.; Chang, S.; Chen, A. B.; Kuo, C.; Su, H.; Hsu, R.; Frey, H. U.; Takahashi, Y.; Lee, L.

    2013-12-01

    The Imager of Sprite and Upper Atmosphere Lightning (ISUAL) onboard the Formosat-2 was launched in May 2004; since then, it has continuously observed transient luminous events (TLEs) within the +/-60 degree of latitude for nearly 10 years. Due to ISUAL's long-term observations, the possible correlation between the TLE and the solar activity can be explored. Among the ISUAL TLEs, elves, which occur at the mesospheric altitude ~90 km and are caused by the heating incurred by the lightning-launched electromagnetic pulse of the lower ionosphere boundary are the most numerous and are the most suitable for this type of study. In previous studies, the elve distribution has proved to be a good surrogate for the lightning with exceptional peak current globally. ISUAL records the occurrence time and the height and location of elves, and the spectral emission intensities at six different band pass including the FUV N2 Lyman-Birge-Hopfield (LBH) band, which is a dominant emission in elves. The LBH intensity not only reflects the peak current of parent lightning, but may also represent the solar-activity-driven-lighting's perturbation to the ionosphere. In this study, we first examine whether the 11-year solar cycle affects the elve activity and altitude by analyzing the elve occurrence rates and heights in different latitudinal regions. To avoid the climatological and instrumental biases in the elve observations, the effects arising from the ENSO and moonlight must be carefully eliminated. Besides, we will discuss the elve variation in shorter time scale due to strong and sudden change of solar activity. Since the ion density of the mesosphere at mid-latitude may be significantly altered during/after a strong corona mass ejection (CME).Furthermore, it has been proven that the changes in the solar X-ray flux dominate the variations in the conductivity profile within the upper characteristic ELF layer (the 90-100km portion of the E-region). we will compare the variation of

  8. 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

  9. Magnetohydrodynamic (MHD) modelling of solar active phenomena via numerical methods

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1988-01-01

    Numerical ideal MHD models for the study of solar active phenomena are summarized. Particular attention is given to the following physical phenomena: (1) local heating of a coronal loop in an isothermal and stratified atmosphere, and (2) the coronal dynamic responses due to magnetic field movement. The results suggest that local heating of a magnetic loop will lead to the enhancement of the density of the neighboring loops through MHD wave compression. It is noted that field lines can be pinched off and may form a self-contained magnetized plasma blob that may move outward into interplanetary space.

  10. The onset of the solar active cycle 22

    NASA Technical Reports Server (NTRS)

    Ahluwalia, H. S.

    1989-01-01

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

  11. 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.

  12. Understanding Activity Cycles of Solar Type Stars with Kepler

    NASA Astrophysics Data System (ADS)

    Tovar, Guadalupe; Montet, Benjamin; Johnson, John A.

    2017-01-01

    As the era of exploring new worlds and systems advances we seek to answer the question: How common is our Sun? There is considerable evidence about the recurring activity cycles of our Sun but very little is known about the activity cycles of other stars. By calibrating the full frame images from the original Kepler mission that were taken once a month over the course of four years, we are able to do relative photometry on roughly 5 million stars. By building a model of the pixel response function we were able to achieve 0.8% precision photometry. We identify 50,000 solar type stars based on magnitude, surface gravity, and temperature cuts. We observe the relative increase and decrease in brightness of the stars indicating signs of activity cycles similar to our Sun. We continue to explore how a data driven pixel response function model could improve our precision to 0.1% photometry measurements.

  13. Eruptions that Drive Coronal Jets in a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.; Panesar, Navdeep K.; Akiyama, Sachiko; Yashiro, Seiji; Gopalswamy, Nat

    2016-01-01

    Solar coronal jets are common in both coronal holes and in active regions (e.g., Shibata et al. 1992, Shimojo et al. 1996, Cirtain et al. 2007. Savcheva et al. 2007). Recently, Sterling et al. (2015), using data from Hinode/XRT and SDO/AIA, found that coronal jets originating in polar coronal holes result from the eruption of small-scale filaments (minifilaments). The jet bright point (JBP) seen in X-rays and hotter EUV channels off to one side of the base of the jet's spire develops at the location where the minifilament erupts, consistent with the JBPs being miniature versions of typical solar flares that occur in the wake of large-scale filament eruptions. Here we consider whether active region coronal jets also result from the same minifilament-eruption mechanism, or whether they instead result from a different mechanism (e.g. Yokoyama & Shibata 1995). We present observations of an on-disk active region (NOAA AR 11513) that produced numerous jets on 2012 June 30, using data from SDO/AIA and HMI, and from GOES/SXI. We find that several of these active region jets also originate with eruptions of miniature filaments (size scale 20'') emanating from small-scale magnetic neutral lines of the region. This demonstrates that active region coronal jets are indeed frequently driven by minifilament eruptions. Other jets from the active region were also consistent with their drivers being minifilament eruptions, but we could not confirm this because the onsets of those jets were hidden from our view. This work was supported by funding from NASA/LWS, NASA/HGI, and Hinode. A full report of this study appears in Sterling et al. (2016).

  14. Solar System Puzzle Kit: An Activity for Earth and Space Science.

    ERIC Educational Resources Information Center

    Vogt, Gregory L.; Rosenberg, Carla B.

    This Solar System Puzzle Kit for grades 5-8, allows students to create an eight-cube paper puzzle of the solar system and may be duplicated for classroom use or used as a take home activity for children and parents. By assembling the puzzle, hand-coloring the bodies of the solar system, and viewing the puzzle's 12 sides, students can reinforce…

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

    SciTech Connect

    Not Available

    1982-01-01

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

  16. Effects of solar cycle 24 activity on WAAS navigation

    NASA Astrophysics Data System (ADS)

    Datta-Barua, Seebany; Walter, Todd; Bust, Gary S.; Wanner, William

    2014-01-01

    This paper reviews the effects of geomagnetic activity of solar cycle 24 from 2011 through mid-2013 on the Federal Aviation Administration's Wide Area Augmentation System (WAAS) navigation service in the U.S., to identify (a) major impacts and their severity compared with the previous cycle and (b) effects in new service regions of North America added since last solar cycle. We examine two cases: a storm that reduced service coverage for several hours and ionospheric scintillation that led to anomalous receiver tracking. Using the 24-25 October 2011 storm as an example, we examine WAAS operational system coverage for the conterminous U.S. (CONUS). The WAAS algorithm upgrade to ionospheric estimation, in effect since late 2011, is able to mitigate the daytime coverage loss but not the nighttime loss. We correlate WAAS availability to maps of the storm plasma generated with the data assimilative model Ionospheric Data Assimilation 4-D, which show a local nighttime corotating persistent plume of plasma extending from Florida across central CONUS. We study the effect of scintillation on 9 October 2012 on the WAAS reference station at Fairbanks, Alaska. Data from a nearby scintillation monitor in Gakona and all-sky imaging of aurora at Poker Flat corroborate the event. Anomalous receiver processing triggered by scintillation reduces accuracy at Fairbanks for a few minutes. Users experiencing similar effects would have their confidence bounds inflated, possibly trading off service continuity for safety. The activity to date in solar cycle 24 has had minor effects on WAAS service coverage, mainly occurring in Alaska and Canada.

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

    NASA Technical Reports Server (NTRS)

    1975-01-01

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

  18. 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.

  19. 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.

  20. Simulation of the solar-activity-weather-ecology chain

    NASA Astrophysics Data System (ADS)

    Obridko, V.; Dmitrieva, B.; Zaborova, E.

    1993-11-01

    The effect of weak solar activity generated disturbances on the ecological system has been investigated. The study is based on simulation of the tundra community `vegetation/lemmings/polar foxes'. The model was verified using the data on the West Taimir ecosystem. The summer duration determined from meteorological indices was taken as the input parameter of the model. If the effect was small enough in amplitude, the model demonstrated 3-year-long intervals between the maxima modulated by the 11-year-cycle. At the second stage of our study we used the real series of summer duration (from setting in to melting of the snow cover) in the region under consideration. When the real summer duration was included in the model, the spectrum displayed an 11-year component that was nearly as pronounced as the observed one. Since the data on summer duration used in the model were taken directly from meteorological stations without processing, the appearance of the 11-year periodicity in the model dynamics may be regarded as additional evidence for dependence of the meteorological series on solar activity.

  1. Hysteresis of indices of solar and ionospheric activity during 11-year cycles

    NASA Astrophysics Data System (ADS)

    Bruevich, E. A.; Kazachevskaya, T. V.; Katyushina, V. V.; Nusinov, A. A.; Yakunina, G. V.

    2016-12-01

    The effects of hysteresis, which is a manifestation of ambiguous relationships between different solar activity indices during the rising and declining phases of solar cycles, are analyzed. The paper addresses the indices characterizing radiation from the solar photosphere, chromosphere, and corona, and the ionospheric indices. The 21st, 22nd, and 23rd solar cycles, which significantly differ from each other in amplitude, exhibit different extents of hysteresis.

  2. ACTIVITY ANALYSES FOR SOLAR-TYPE STARS OBSERVED WITH KEPLER. I. PROXIES OF MAGNETIC ACTIVITY

    SciTech Connect

    He, Han; Wang, Huaning; Yun, Duo

    2015-11-15

    Light curves of solar-type stars often show gradual fluctuations due to rotational modulation by magnetic features (starspots and faculae) on stellar surfaces. Two quantitative measures of modulated light curves are employed as the proxies of magnetic activity for solar-type stars observed with Kepler telescope. The first is named autocorrelation index i{sub AC}, which describes the degree of periodicity of the light curve; the second is the effective fluctuation range of the light curve R{sub eff}, which reflects the depth of rotational modulation. The two measures are complementary and depict different aspects of magnetic activities on solar-type stars. By using the two proxies i{sub AC} and R{sub eff}, we analyzed activity properties of two carefully selected solar-type stars observed with Kepler (Kepler ID: 9766237 and 10864581), which have distinct rotational periods (14.7 versus 6.0 days). We also applied the two measures to the Sun for a comparative study. The result shows that both the measures can reveal cyclic activity variations (referred to as i{sub AC}-cycle and R{sub eff}-cycle) on the two Kepler stars and the Sun. For the Kepler star with the faster rotation rate, i{sub AC}-cycle and R{sub eff}-cycle are in the same phase, while for the Sun (slower rotator), they are in the opposite phase. By comparing the solar light curve with simultaneous photospheric magnetograms, it is identified that the magnetic feature that causes the periodic light curve during solar minima is the faculae of the enhanced network region, which can also be a candidate of magnetic features that dominate the periodic light curves on the two Kepler stars.

  3. 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.

  4. Characteristics of the 23 Cycle of Solar Activity

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Tamara

    The aim of the present study is to search for special features of the 23-d cycle of solar activity. We present results of our analysis of spectra of sunspot number W for the time intervals of spaced measurements 1964-1997 and 1996-2005 and of the Interplanetary Magnetic Field (IMF), the solar wind velocity (V) calculated on the basis of measurements near the Earth's orbit for the period 1964-1997. A method of non-linear spectral analysis named by us the Method of Global Minimum (MGM) is used. MGM allows self-consistentidentification of trends from data and non-stationary sinusoids and estimation of statistical significance of spectral components. The IMF and W spectra for the period 1964-1997 both show the solar cycle at T=10.8 yr and its higher harmonics. But spectrum of sunspot number W for the period 1996-2005 (time interval of the 23-d cycle) has not spectral component at T=10.8 yr (at confidence statistical level 95%); however, this spectrum has higher harmonics of the 10.8-yr cycle (such as sinusoid with T=146.2 day). The most powerful spectral line from the spectrum (1996-2005) has period T=16.56 yr. We show that tide forces of the planets can be a cause of periodical changes in the analyzed data. Periods of perturbed tide forces of external planets and their higher harmonics (connected with motion of the Sun relative to the mass center of the solar system) are detected in the spectra. In particular, all periods from the spectrum of W for the period 1996-2005 can be interpreted as periods of perturbed tide force of a system: Sun - a pair Jupiter-Uranus: T=16.56 yr is period of perturbed tide force of pair Jupiter-Uranus (1st planet determines shift of mass center of the Sun relative to the mass center of a system the Sunthe 1st planet; the 2nd planet determines perturbed tide force acting on the Sun). The fact that spectrum of W for the period 1996-2005 has the most power spectral components at T=16.56 and T=1.83 yr (9 harmonics of the 16.56-yr cycle

  5. 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

  6. Characterization of local self-similarity and criticality in the solar active regions

    NASA Astrophysics Data System (ADS)

    Rosa, R. R.; Vats, H. O.; Ramos, F. M.; Zanandrea, A.; Rodrigues Neto, C.; Fernandes, F. C. R.; Bolzan, M. J. A.; Rempel, E. L.; Brito, R. C.; Vijaykumar, N. L.; Sawant, H. S.

    From solar radio burst data we computed wavelet transforms and frequency distribution for investigation of self-similar temporal variability and power-laws, as the fundamental conditions for characterization of dynamical criticality (self or forced) in the solar active regions. The main result indicates that, as for the global activity, the local coronal magnetic field, in millisecond time scales, can be in a critical state where the dynamics of solar active regions works as avalanches of many small intermittent particle acceleration events.

  7. Possible Relationship of the Solar Activity and Earthquakes

    NASA Astrophysics Data System (ADS)

    Gonzalez-Trejo, J. I.; Cervantes, F.; Real-Ramírez, C. A.; Hoyos-Reyes, L. F.; Miranda-Tello, R.; Area de Sistemas Computacionales

    2013-05-01

    Several authors have recently argued that there is a relationship between solar activity and big earthquakes. This work compares Dst index fluctuations along 2012 and 2013, with the earthquake activity near La Paz, Baja California, Mexico. The earthquakes measurements at this place were divided according its deep focus. It was observed that the frequency of the deeper earthquakes increases shortly after considerable fluctuations in the Dst index are registered. We assume that the number of deep earthquakes increases because the interaction of the tectonic plate below that place and the tectonic plates in contact with it increases. This work also shows that the frequency of shallowest minor and light earthquakes increases shortly before a strongest earthquake takes place in the vicinity.

  8. 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.

  9. Coronal abundances in solar active regions measured by the Solar Maximum Mission flat crystal spectrometer

    NASA Technical Reports Server (NTRS)

    Saba, Julia L. R.; Strong, Keith T.

    1992-01-01

    High resolution soft X-ray spectra acquired by the Flat Crystal Spectrometer (FCS) on solar Maximum Mission provide an excellent data base to study the relative abundances of O, Ne, Mg, and Fe in solar active regions. The FCS data show significant variability for all combinations of these elements. The largest variation occurs for Fe:Ne, which shows region to region changes of up to a factor of 7, and frequent factor of 2 variations in day to day samples of a given region. The atomic data and the ionization balance calculations used to interpret the line ratios affect the actual abundance values obtained, but have little effect on the magnitude of the total range of variation inferred. Resonance scattering of Fe XVII could cause a systematic offset in the abundances determined, but cannot be responsbile for the bulk of the observed variability. While abundance variability complicates the derivation of plasma parameters from spectroscopic measurements, it should offer exciting new clues to the processes which form and heat the corona.

  10. Chromospheric and photospheric evolution of an extremely active solar region in solar cycle 19

    NASA Technical Reports Server (NTRS)

    Mckenna-Lawlor, S. M. P.

    1981-01-01

    a comprehensive investigation was made of phenomena attending the disk passage, July 7 to 21, 1959, of active solar center HAO-59Q. At the photospheric level that comprised an aggregate of groups of sunspots of which one group, Mt. Wilson 14284, showed all the attributes deemed typical of solar regions associated with the production of major flares. A special characteristic of 59Q was its capability to eject dark material. Part of this material remained trapped in the strong magnetic fields above group 14284 where it formed a system of interrelated arches, the legs of which passed through components of the bright chromospheric network of the plage and were rooted in various underlying umbrae. Two apparently diffeent kinds of flare were identified in 59Q; namely, prominence flares (which comprised brightenings within part of the suspended dark prominence) and plage flares (which comprised brightenings within part of the chromospheric network). Prominence flares were of three varieties described as 'impact', 'stationary' and 'moving' prominence flares. Plage flares were accompanied in 3 percent of cases by Type III bursts. These latter radio events indicate the associated passage through the corona of energetic electrons in the approximate energy range 10 to 100 keV. At least 87.5 percent, and probably all, impulsive brightenings in 59Q began directly above minor spots, many of which satellites to major umbrae. Stationary and moving prominence flares were individually triggered at sites beneath which magnetic changes occurred within intervals which included each flare's flash phase.

  11. Parker Lecture - Prominences: the key to understanding solar activity

    NASA Astrophysics Data System (ADS)

    Karpen, Judith T.

    2011-05-01

    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 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 prominence

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

    NASA Astrophysics Data System (ADS)

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

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

  13. Magnetic-field variations and solar flare activity

    NASA Astrophysics Data System (ADS)

    Grigor'eva, I. Yu.; Shakhovskaya, A. N.; Livshits, M. A.; Knyazeva, I. S.

    2012-11-01

    Solar filtergrams obtained at the Crimean Astrophysical Observatory at the center and wings of the H α line are used to study variations in filaments, in particular, in arch filament systems (AFSs). These are considered as an indicator of emerging new magnetic flux, providing information about the spatial locations of magnetic-field elements. Magnetic-field maps for the active region NOAA 10030 are analyzed as an example. A method developed earlier for detecting elements of emerging flux using SOHO/MDI magnetograms indicates a close link between the increase in flare activity in theNOAA 10030 group during July 14-18, 2002 and variations in the topological disconnectedness of the magnetograms. Moreover, variations in the flare activity one day before a flare event are correlated with variations in the topological complexity of the field (the Euler characteristic) in regions with high field strengths (more than 700 G). Analysis of multi-wavelength polarization observations on the RATAN-600 radio telescope during July 13-17, 2002 indicate dominance of the radio emission above the central spot associated with the increase in flare activity. In addition to the flare site near the large spot in the group, numerous weak flares developed along an extended local neutral line, far from the central line of the large-scale field. The statistical characteristics of the magnetic-field maps analyzed were determined, and show flare activity of both types, i.e., localized in spot penumbras and above the neutral line of the field.

  14. Solar activity effects on the equatorial thermosphere temperature profile

    NASA Astrophysics Data System (ADS)

    Arduini, C.; Laneve, G.; Nobile, L.

    In this paper we present the effects of solar activity on the temperature profiles of the equatorial thermosphere as derived from the neutral density data collected by the San Marco 5 (SM5) satellite. This satellite flew during the increasing part of the solar cycle 22 (1988). It had a quasi-equatorial orbit, with inclination lower than 3 deg. The range of measurements, from April to December, allows the inference of seasonal and diurnal effects on the temperature profiles. The density data are collected every second along arcs of orbit lasting up to 50 minutes. The analysis of these densities has been already partially presented and provided evidence for several interesting features, in particular the vertical structure of the diurnal harmonic content and its seasonal variations. The temperatures derived from the same data set provide a useful complement to this picture. The SM5 satellite carried on board 5 instruments for studying the equatorial ionosphere and thermosphere, among them, the Drag Balance Instrument (DBI) for measuring the neutral density and the Ion Drift Meter and Potential Retarding Analyzer (IVI) that allow the evaluation of ions concentration, velocity and temperature. It is possible, therefore, to compare the neutral temperature derived from the neutral density data with the ion temperature given by the IVI.

  15. SIMULATION OF THE FORMATION OF A SOLAR ACTIVE REGION

    SciTech Connect

    Cheung, M. C. M.; Title, A. M.; Rempel, M.; Schuessler, M.

    2010-09-01

    We present a radiative magnetohydrodynamics simulation of the formation of an active region (AR) on the solar surface. The simulation models the rise of a buoyant magnetic flux bundle from a depth of 7.5 Mm in the convection zone up into the solar photosphere. The rise of the magnetic plasma in the convection zone is accompanied by predominantly horizontal expansion. Such an expansion leads to a scaling relation between the plasma density and the magnetic field strength such that B {proportional_to} rhov{sup 1/2}. The emergence of magnetic flux into the photosphere appears as a complex magnetic pattern, which results from the interaction of the rising magnetic field with the turbulent convective flows. Small-scale magnetic elements at the surface first appear, followed by their gradual coalescence into larger magnetic concentrations, which eventually results in the formation of a pair of opposite polarity spots. Although the mean flow pattern in the vicinity of the developing spots is directed radially outward, correlations between the magnetic field and velocity field fluctuations allow the spots to accumulate flux. Such correlations result from the Lorentz-force-driven, counterstreaming motion of opposite polarity fragments. The formation of the simulated AR is accompanied by transient light bridges between umbrae and umbral dots. Together with recent sunspot modeling, this work highlights the common magnetoconvective origin of umbral dots, light bridges, and penumbral filaments.

  16. Statistical pecularities of 24th cycle of solar activity

    NASA Astrophysics Data System (ADS)

    Efimenko, V.; Lozitsky, V.

    2016-06-01

    Current 24th cycle of solar activity is anomalous if following aspects: 1) it had non-monotonous phase of grown, and on different times of this phase it demonstrated peculiarities of both middle and weak cycle, 2) peak of cycle was two-top, and second top was higher than first on about 15 units of averages Wolf's number (in old classification) that is maximum value for all previous cycles, and 3) temporal interval between first and second maximums of cycle was 26 months that is second value from all 24 cycles. As to index of integral distribution of sunspot diameters, it was found earlier that this index α, in the average, equals about 6.0 for 7 previous cycles, in diameter range 50–90 Mm. New statistical analysis based on data for 2010–2015 allows to conclude that for 24th cycle α ≈ 5.8. Thus, dispersion of diameters of sunspots in 24th cycle is typical for majority of solar cycles.

  17. Monitoring Solar Activity Trends With a Simple Sunspotter

    NASA Astrophysics Data System (ADS)

    Larsen, K.

    2013-11-01

    With the Sun now in solar maximum, solar observations are a timely means to interest students and the general public in astronomy in general and variable stars in particular. The commercially produced Sunspotter is a solar projection system that allows for safer solar observations by several individuals simultaneously. Educational uses for the Sunspotter are reviewed, and the ability of the instrument to track trends in the sunspot cycle (compared to a standard telescope and the American Relative Sunspot Number (Ra)) is examined.

  18. A Forecast of Reduced Solar Activity and Its Implications for NASA

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth; Franz, Heather

    2005-01-01

    The "Solar Dynamo" method of solar activity forecasting is reviewed. Known generically as a 'precursor" method, insofar as it uses observations which precede solar activity generation, this method now uses the Solar Dynamo Amplitude (SODA) Index to estimate future long-term solar activity. The peak amplitude of the next solar cycle (#24), is estimated at roughly 124 in terms of smoothed F10.7 Radio Flux and 74 in terms of the older, more traditional smoothed international or Zurich Sunspot number (Ri or Rz). These values are significantly smaller than the amplitudes of recent solar cycles. Levels of activity stay large for about four years near the peak in smoothed activity, which is estimated to occur near the 2012 timeflame. Confidence is added to the prediction of low activity by numerous examinations of the Sun s weakened polar field. Direct measurements are obtained by the Mount Wilson Solar Observatory and the Wilcox Solar Observatory. Further support is obtained by examining the Sun s polar faculae (bright features), the shape of coronal soft X-ray "holes," and the shape of the "source surface" - a calculated coronal feature which maps the large scale structure of the Sun s field. These features do not show the characteristics of well-formed polar coronal holes associated with typical solar minima. They show stunted polar field levels, which are thought to result in stunted levels of solar activity during solar cycle #24. The reduced levels of solar activity would have concomitant effects upon the space environment in which satellites orbit. In particular, the largest influences would affect orbit determination of satellites in LEO (Low Earth Orbit), based upon the altered thermospheric and exospheric densities. A decrease in solar activity would result in smaller satellite decay rates, as well as fewer large solar events that can destroy satellite electronic functions. Other effects of reduced solar activity upon the space environment include enhanced

  19. Solar activity cycle and the incidence of foetal chromosome abnormalities detected at prenatal diagnosis

    NASA Astrophysics Data System (ADS)

    Halpern, Gabrielle J.; Stoupel, Eliahu G.; Barkai, Gad; Chaki, Rina; Legum, Cyril; Fejgin, Moshe D.; Shohat, Mordechai

    1995-06-01

    We studied 2001 foetuses during the period of minimal solar activity of solar cycle 21 and 2265 foetuses during the period of maximal solar activity of solar cycle 22, in all women aged 37 years and over who underwent free prenatal diagnosis in four hospitals in the greater Tel Aviv area. There were no significant differences in the total incidence of chromosomal abnormalities or of trisomy between the two periods (2.15% and 1.8% versus 2.34% and 2.12%, respectively). However, the trend of excessive incidence of chromosomal abnormalities in the period of maximal solar activity suggests that a prospective study in a large population would be required to rule out any possible effect of extreme solar activity.

  20. 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.

  1. Effects of Space Weather on Biomedical Parameters during the Solar Activity Cycles 23-24.

    PubMed

    Ragul'skaya, M V; Rudenchik, E A; Chibisov, S M; Gromozova, E N

    2015-06-01

    The results of long-term (1998-2012) biomedical monitoring of the biotropic effects of space weather are discussed. A drastic change in statistical distribution parameters in the middle of 2005 was revealed that did not conform to usual sinusoidal distribution of the biomedical data reflecting changes in the number of solar spots over a solar activity cycle. The dynamics of space weather of 2001-2012 is analyzed. The authors hypothesize that the actual change in statistical distributions corresponds to the adaptation reaction of the biosphere to nonstandard geophysical characteristics of the 24th solar activity cycle and the probable long-term decrease in solar activity up to 2067.

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

    SciTech Connect

    Sorriso-Valvo, L.; De Vita, G.; Kazachenko, M. D.; Krucker, S.; Welsch, B. T.; Fisher, G. H.; Primavera, L.; Servidio, S.; Lepreti, F.; Carbone, V.; Vecchio, A.

    2015-03-01

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

  3. Minimum extreme temperature in the gulf of mexico: is there a connection with solar activity?

    NASA Astrophysics Data System (ADS)

    Maravilla, D.; Mendoza, B.; Jauregui, E.

    Minimum extreme temperature ( MET) series from several meteorological stations of the Gulf of Mexico are spectrally analyzed using the Maximum Entrophy Method. We obtained periodicities similar to those found in the sunspot number, the magnetic solar cycle, comic ray fluxes and geomagnetic activity which are modulated by solar activity. We suggested that the solar signal is perhaps present in the MET record of this region of Mexico.

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

    NASA Astrophysics Data System (ADS)

    Pogrebnoy, V.; Malosiev, T.

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

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

    NASA Astrophysics Data System (ADS)

    Chintzoglou, Georgios

    2016-04-01

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

  6. 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.

  7. 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.

  8. Aneurysmal subarachnoid hemorrhage: relationship to solar activity in the United States, 1988-2010.

    PubMed

    Rosenbaum, Benjamin P; Weil, Robert J

    2014-07-01

    Aneurysmal subarachnoid hemorrhage (SAH) is a common condition treated by neurosurgeons. The inherent variability in the incidence and presentation of ruptured cerebral aneurysms has been investigated in association with seasonality, circadian rhythm, lunar cycle, and climate factors. We aimed to identify an association between solar activity (solar flux and sunspots) and the incidence of aneurysmal SAH, all of which appear to behave in periodic fashions over long time periods. The Nationwide Inpatient Sample (NIS) provided longitudinal, retrospective data on patients hospitalized with SAH in the United States, from 1988 to 2010, who underwent aneurysmal clipping or coiling. Solar activity and SAH incidence data were modeled with the cosinor methodology and a 10-year periodic cycle length. The NIS database contained 32,281 matching hospitalizations from 1988 to 2010. The acrophase (time point in the cycle of highest amplitude) for solar flux and for sunspots were coincident. The acrophase for aneurysmal SAH incidence was out of phase with solar activity determined by non-overlapping 95% confidence intervals (CIs). Aneurysmal SAH incidence peaks appear to be delayed behind solar activity peaks by 64 months (95% CI; 56-73 months) when using a modeled 10-year periodic cycle. Solar activity (solar flux and sunspots) appears to be associated with the incidence of aneurysmal SAH. As solar activity reaches a relative maximum, the incidence of aneurysmal SAH reaches a relative minimum. These observations may help identify future trends in aneurysmal SAH on a population basis.

  9. Solar technology assessment project. Volume 3: Active space heating and hot water supply with solar energy

    NASA Astrophysics Data System (ADS)

    Karaki, S.; Loef, G. O. G.

    1981-04-01

    Several types of solar water heaters are described and assessed. These include thermosiphon water heaters and pump circulation water heaters. Auxiliary water heating is briefly discussed, and new and retrofit systems are compared. Liquid-based space heating systems and solar air heaters are described and assessed, auxiliary space heating are discussed, and new and retrofit solar space heating systems are compared. The status of flat plate collectors, evacuated tube collectors, and thermal storage systems is examined. Systems improvements, reliability, durability and maintenance are discussed. The economic assessment of space and water heating systems includes a comparison of new systems costs with conventional fuels, and sales history and projections. The variety of participants in the solar industry and users of solar heat is discussed, and various incentives and barriers to solar heating are examined. Several policy implications are discussed, and specific government actions are recommended.

  10. Background Sizes of the Solar and Interplanetary Active Phenomena Physical Characteristics in Conditions of the Deep and Prolonged Solar Minimum

    NASA Astrophysics Data System (ADS)

    Ishkov, Vitaly

    The last phase of a minimum begun in May, 2005. Since January, 2009 the solar cycle 24 has begun, and its development goes normal rate, without surprises. In this minimum, side by side with the periods of very high flare activity (IX 2005 and XII 2006 -+5.5 and +6.6 years after a maximum) which on flare potential occupy 4 and 20 place among the most flare-active regions for the last 4 cycles . The Sun within 772 days (on February.2010) was sunspotless. Last three years of a minimum phase give the chance to estimate and analyse the solar active phenomena in the conditions of the lesser generation of solar magnetic fields. It has led to significant falling of an interplanetary magnetic field background level that has in turn predetermined 20

  11. Solar-stellar connection : A solar analogous behaviour by an active ultra fast rotator

    NASA Astrophysics Data System (ADS)

    Sairam, Lalitha; Schmitt, Juergen; Pal Singh, Kulinder

    2015-08-01

    AB Dor is an ultra-fast rotating (Prot ~ 0.51 d) active young K dwarf with an age of ~40-50 Myr. Located as a foreground star towards large magellanic cloud (LMC), AB Dor has the advantage of being observed at all times by most of the X-ray satellites making it a favourite calibration target. AB Dor has been repeatedly observed for calibration by reflection grating spectrometer (RGS) on board XMM- Newton over last decade. This gives an ideal opportunity to perform a detailed analysis of the coronal emission, and to compare the flare characteristics with the Sun, since the Sun is usually considered as a prototype of low mass stars. Flares are frequent in low mass active stars across the electromagnetic spectrum similar to the Sun. We will for the first time, present an analysis of 30 intense X-ray flares observed from AB Dor. These flares detected in XMM-Newton data show a rapid rise (500-3000 s) and a slow decay (1000-6000 s). The derived X-ray luminosity during the flares ranges between 30.20 ≤ log(Lx) ≤ 30.83 erg/s; the flare peak temperature lies between 30-80 MK and the emission measures for these flares are in the range of 52.3 ≤ log(EM) ≤ 53.5 cm^-3. Our studies suggest that the scaling law between the flare peak emission measure and the flare peak temperature for all the flares observed on AB Dor is very similar to the relationship followed by solar flares, despite the fact that the AB Dor flare emission is ~250 times higher than the solar flare emission. We also carried out a homogenous study of flare frequencies, energetics and its occurrence in AB Dor. The frequency distribution of flare energies is a crucial diagnostic to calculate the overall energy residing in a flare. Our results of this study indicate that the large flare (33 ≤ log(E) ≤ 34 erg) may not contribute to the heating of the corona. We will show the presence of a possible long-term cycle in AB Dor both from a photospheric and coronal point of view, similar to the 11-year

  12. Solar flare acceleration of solar wind: influence of active region magnetic field.

    PubMed

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

    1981-06-26

    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.

  13. A Survey of Nanoflare Properties in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Viall, N. M.; Klimchuk, J. A.

    2013-12-01

    We investigate coronal heating using a systematic technique to analyze the properties of nanoflares in active regions (AR). Our technique computes cooling times, or time-lags, on a pixel-by-pixel basis using data taken with the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. Our technique has the advantage that it allows us to analyze all of the coronal AR emission, including the so-called diffuse emission. We recently presented results using this time-lag analysis on NOAA AR 11082 (Viall & Klimchuk 2012) and found that the majority of the pixels contained cooling plasma along their line of sight, consistent with impulsive coronal nanoflare heating. Additionally, our results showed that the nanoflare energy is stronger in the AR core and weaker in the active region periphery. Are these results representative of the nanoflare properties exhibited in the majority of ARs, or is AR 11082 unique? Here we present the time-lag results for a survey of ARs and show that these nanoflare patterns are born out in other active regions, for a range of ages, magnetic complexity, and total unsigned magnetic flux. Other aspects of the nanoflare properties, however, turn out to be dependent on certain AR characteristics.

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

    SciTech Connect

    Not Available

    1982-01-01

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

  15. Relationships between solar activity and climate change. [sunspot cycle effects on lower atmosphere

    NASA Technical Reports Server (NTRS)

    Roberts, W. O.

    1974-01-01

    Recurrent droughts are related to the double sunspot cycle. It is suggested that high solar activity generally increases meridional circulations and blocking patterns at high and intermediate latitudes, especially in winter. This effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

  16. An analysis of solar-cycle temporal relationships among activity indicators

    NASA Astrophysics Data System (ADS)

    Bachmann, K. T.; Maymani, H.; Nautiyal, K.; te Velde, V.

    2004-01-01

    Differences in the time development of solar activity indices are an important clue in the search for physical processes responsible for changing solar emission at various wavelengths. In this paper we describe our investigation of temporal relationships among two space-based indices, Lyman-α 121.6 nm emission (Lα) and the Mg II 280 nm core-to-wing ratio, and four ground-based indices - the 10.7 cm flux (F10), the He I 1083 nm equivalent width, the Ca II K 393.4 nm emission index, and the International Sunspot Number (ISN). We provide scatterplots of index pairs passed through a 2-year Gaussian filter during each available solar cycle, and we approximate the temporal relationships quantitatively as overall temporal offsets with uncertainties. We reconcile our findings with qualitative ideas concerning the variation of solar emissions with solar activity. Since the F10 and ISN time series are longer than four complete solar cycles, we are able to evaluate the reproducibility of temporal offsets over multiple solar cycles. The chief motivation for our work is to improve solar indicator analysis by providing a method of seeing and analyzing temporal relationships clearly and easily. We believe that future physical models of magnetic activity and spectral emissions in the solar chromosphere and transition region may make quantitative predictions of temporal relationships among full-disk solar indices for comparison with analyses such as ours.

  17. Activity of processes on the visible surfaces of Solar System bodies

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.

    2016-10-01

    We consider the physical processes on the surfaces of Solar System bodies, which lead to visible changes in their reflective characteristics. It is shown that each body in the Solar system has a set of chemical elements and their compounds, converting of which indicates significant activity in such a significant temperature change range from 700 K (for Mercury) to 30 K for Pluto. That is, all objects in the Solar system show a significant activity. However, they are very individual for the list and the type of the processes that take place on each body in the Solar system.

  18. A Study of Solar Magnetic Fields Below the Surface, at the Surface, and in the Solar Atmosphere - Understanding the Cause of Major Solar Activity

    NASA Astrophysics Data System (ADS)

    Chintzoglou, Georgios

    2016-05-01

    The fundamental processes regarding the origin, emergence and evolution of solar magnetic fields as well as the generation of solar activity are largely unknown or remain controversial. In this dissertation, multiple important issues regarding solar magnetism and activities are addressed, based on advanced observations obtained by the AIA and HMI instruments aboard the SDO spacecraft.This dissertation addresses the 3D magnetic structure of complex emerging Active Regions (ARs). In ARs the photospheric fields might show all aspects of complexity, from simple bipolar regions to extremely complex multipolar surface magnetic distributions. Here, we introduce a novel technique to infer the subphotospheric configuration of emerging magnetic flux tubes forming ARs on the surface. Using advanced 3D visualization tools with this technique on a complex flare and CME productive AR, we found that the magnetic flux tubes forming the complex AR may originate from a single progenitor flux tube in the SCZ. The complexity can be explained as a result of vertical and horizontal bifurcations that occurred on the progenitor flux tube.In addition, this dissertation proposes a new scenario on the origin of major solar activity. When more than one flux tubes are in close proximity to each other while they break through the photospheric surface, collision and shearing may occur as they emerge. Once this collisional shearing occurs between nonconjugated sunspots (opposite polarities not belonging to the same bipole), major solar activity is triggered. The collision and shearing occur due to the natural separation of polarities in emerging bipoles. In this continuous collision, more poloidal flux is added to the system effectively creating an expanding MFR into the corona, accompanied by filament formation above the PIL together with flare activity and CMEs. Our results reject two popular scenarios on the possible cause of solar eruptions (1) shearing motion between conjugate polarities, (2

  19. 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.

  20. Helium Line Formation and Abundance in a Solar Active Region

    NASA Astrophysics Data System (ADS)

    Mauas, P. J. D.; Andretta, V.; Falchi, A.; Falciani, R.; Teriaca, L.; Cauzzi, G.

    2005-01-01

    An observing campaign (SOHO JOP 139), coordinated between ground-based and Solar and Heliospheric Observatory (SOHO) instruments, has been planned to obtain simultaneous spectroheliograms of the same active region in several spectral lines. The chromospheric lines Ca II K, Hα, and Na I D, as well as He I 10830, 5876, 584, and He II 304 Å lines have been observed. The EUV radiation in the range λ<500 Å and in the range 260<λ<340 Å has also been measured at the same time. These simultaneous observations allow us to build semiempirical models of the chromosphere and low transition region of an active region, taking into account the estimated total number of photoionizing photons impinging on the target active region and their spectral distribution. We obtained a model that matches very well all the observed line profiles, using a standard value for the He abundance ([He]=0.1) and a modified distribution of microturbulence. For this model we study the influence of the coronal radiation on the computed helium lines. We find that, even in an active region, the incident coronal radiation has a limited effect on the UV He lines, while it is of fundamental importance for the D3 and 10830 Å lines. Finally, we build two more models, assuming values of He abundance [He]=0.07 and 1.5, only in the region where temperatures are >1×104 K. This region, between the chromosphere and transition region, has been indicated as a good candidate for processes that might be responsible for strong variations of [He]. The set of our observables can still be well reproduced in both cases, changing the atmospheric structure mainly in the low transition region. This implies that, to choose between different values of [He], it is necessary to constrain the transition region with different observables, independent of the He lines.

  1. Two Types of Coronal Bright Points in the 24-th Cycle of Solar Activity

    NASA Astrophysics Data System (ADS)

    Sherdanov, Chori T.; Minenko, Ekaterina P.; Tillaboev, A. M.; Sattarov, Isroil

    We applied an automatic program for identification of coronal bright points (CBPs) to the data obtained by SOHO/EIT observations taken at the wavelength 195 Å, in the time interval from the end of the 23rd to the early 24th solar cycle. We studied the total number of CBPs and its variations at the beginning of the given cycle of solar activity, so that the development of the solar activity could be predicted with the use of CBPs. For a primary reference point for the 24th solar cycle, we took the emergence of a high-latitude sunspot with the reversed polarity, which appeared in January, 2008. We show that the observed number of CBPs reaches the highest point around the minimum of the solar activity, which in turn may result from the effect of visibility. The minimum solar activity at this time provides the opportunity to register the number of CBPs with the highest accuracy, with its uniform latitudinal distribution. We also study the properties of CBPs in a new 24th cycle of solar activity. It is shown that variations in the cyclic curve of the number of coronal bright points associated with variations in the solar activity, for the latitudes of the quiet Sun to be anticorrelation characteristic changes in the number CBPs to the solar activity, and the observational data are for the regions of active formations on the Sun almost identical on character on the equatorial latitude, but this have lightly expressed character in high-latitude zone. To explain the cyclic curves of variation in the number of coronal bright points in connection with the solar cycle in different latitudinal zones, we suggest a hypothesis of the existence of two types of coronal bright points: those associated with the quiet corona and those related to active formations.

  2. 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.

  3. Outline of the Solar System: Activities for elementary students

    NASA Technical Reports Server (NTRS)

    Hartsfield, J.; Sellers, M.

    1990-01-01

    An introduction to the solar system for the elementary school student is given. The introduction contains historical background, facts, and pertinent symbols concerning the sun, the nine major planets and their moons, and information about comets and asteroids. Aids to teaching are given, including a solar system crossword puzzle with answers.

  4. Solar and Geomagnetic Activity Relation for the Last two Solar Cycles

    NASA Astrophysics Data System (ADS)

    Kilcik, A.; Yiǧit, E.; Yurchyshyn, V.; Ozguc, A.; Rozelot, J. P.

    2017-01-01

    The long-term relationship between solar (sunspot counts in different Zurich sunspot groups, International Sunspot Number (ISSN), solar wind, and X-Ray solar flare index and geomagnetic indices (Ap and Dst) is investigated. Data sets used in this study cover a time period from January 1996 to March 2014. Our main findings are as follows: 1) The best correlation between the sunspot counts and the Ap index are obtained for the large group time series, while the other categories exhibited lower (final and medium) or no correlation at all (small). It is interesting to note that Ap index is delayed by about 13 months relatively to all sunspot count series and ISSN data. 2) The best correlation between the sunspot counts and the Dst index was as well obtained for the large AR time series. The Dst index delays with respect to the large group by about 2 months. 3) The highest correlation between the solar and geomagnetic indices were obtained between the solar wind speed and Ap and Dst indices with zero time delays (r = 0.76, r = 0.52, respectively). 4) The correlation coefficients between the geomagnetic indices (Ap, Dst) and X-Ray solar flare index (r = 0.59, r = -0.48, respectively) are a little higher than the correlation coefficients between these geomagnetic indices and ISSN (r = 0.57, r = -0.43, respectively). 5) The magnitude of all solar and geomagnetic indices (except the solar wind speed) has significantly decreased during the current solar cycle as compared to the same phase of the previous cycle.

  5. Polar low-speed solar wind at the solar activity maximum

    NASA Astrophysics Data System (ADS)

    Ohmi, T.; Kojima, M.; Yokobe, A.; Tokumaru, M.; Fujiki, K.; Hakamada, K.

    2001-11-01

    The tomographic analysis of interplanetary scintillation (IPS) showed that low-speed winds (<= 370 kms-1) emanated out from the polar region at the last solar activity maximum. In order to investigate the origin of those low-speed winds, we compared the velocity distribution derived from the IPS tomographic analysis to the magnetic field structure derived from the potential field analysis. We found that the polar low-speed winds appeared for a short period just before and after the disappearance of polar open fields. When the polar coronal hole shrank very small before its disappearance, the coronal polar open field was encircled by large-scale closed loops and became super radially diverging field into the interplanetary space. A low-speed region appeared in this diverging polar magnetic field region. This situation is a condition very similar to the compact low-speed streams associated with equatorial active regions, which were found by Kojima et al. [1999]. After the open field regions had disappeared from the pole, the polar regions were occupied with closed loops. These closed loops were overlapped by the magnetic field which fanned out from the midlatitudes. A low-speed streamer located above these closed loops even after the polar open field had disappeared. The velocities of polar low-speed streams before polar hole disappearance were much lower than those after disappearance. This result suggests that the physical conditions to generate much lower speed streams are closely associated with large expansion from small open field regions encircled by large-scale closed loops. Finally, a reliability of the IPS measurement of polar low-speed wind was examined by simulating synthetic IPS observations in hypothetical model polar streams.

  6. THE EXPANSION OF ACTIVE REGIONS INTO THE EXTENDED SOLAR CORONA

    SciTech Connect

    Morgan, Huw; Jeska, Lauren; Leonard, Drew

    2013-06-01

    Advanced image processing of Large Angle and Spectrometric Coronagraph Experiment (LASCO) C2 observations reveals the expansion of the active region closed field into the extended corona. The nested closed-loop systems are large, with an apparent latitudinal extent of 50 Degree-Sign , and expanding to heights of at least 12 R{sub Sun }. The expansion speeds are {approx}10 km s{sup -1} in the AIA/SDO field of view, below {approx}20 km s{sup -1} at 2.3 R{sub Sun }, and accelerate linearly to {approx}60 km s{sup -1} at 5 R{sub Sun }. They appear with a frequency of one every {approx}3 hr over a time period of around three days. They are not coronal mass ejections (CMEs) since their gradual expansion is continuous and steady. They are also faint, with an upper limit of 3% of the brightness of background streamers. Extreme ultraviolet images reveal continuous birth and expansion of hot, bright loops from a new active region at the base of the system. The LASCO images show that the loops span a radial fan-like system of streamers, suggesting that they are not propagating within the main coronal streamer structure. The expanding loops brighten at low heights a few hours prior to a CME eruption, and the expansion process is temporarily halted as the closed field system is swept away. Closed magnetic structures from some active regions are not isolated from the extended corona and solar wind, but can expand to large heights in the form of quiescent expanding loops.

  7. Seismic Study of The Solar Interior: Inferences from SOI/MDI Observations during Solar Activity

    NASA Technical Reports Server (NTRS)

    Korzennik, Sylvain G.

    2003-01-01

    The principal investigator describes several types of solar research conducted during the reporting period and gives a statement of work to be performed in the following year. Research conducted during the reporting period includes: exhaustive analysis of observational and instrumental effects that might cause systematic errors in the characterization of high-degree p-modes; study of the structure, asphericity and dynamics of the solar interior from p-mode frequencies and frequency splittings; characterizing the solar rotation; Time-Distance inversion; and developing and using a new peak-fitting method for very long MDI time series at low degrees.

  8. H-alpha synoptic charts of solar activity during the first year of solar cycle 20, October 1964 - August 1965. [Skylab program

    NASA Technical Reports Server (NTRS)

    Mcintosh, P. S.

    1975-01-01

    Solar activity during the period October 28, 1964 through August 27, 1965 is presented in the form of charts for each solar rotation constructed from observations made with the chromospheric H-alpha spectra line. These H-alpha synoptic charts are identical in format and method of construction to those published for the period of Skylab observations. The sunspot minimum marking the start of Solar Cycle 20 occurred in October, 1964; therefore, charts represent solar activity during the first year of this solar cycle.

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

    PubMed

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

    2012-04-17

    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 (10)Be and (14)C 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 (10)Be ice core records from Greenland and Antarctica with the global (14)C tree ring record using principal component analysis. This approach is only possible due to a new high-resolution (10)Be 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.

  10. 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

  11. Distribution of the activity of the Sun during an average solar cycle

    NASA Astrophysics Data System (ADS)

    Svoreň, J.

    2015-12-01

    The paper offers a look at distribution of solar activity during an average solar cycle. Activity profiles in solar cycles from 13 to 17 and from 18 to 22 were studied based on the relative sunspot numbers. The average values for both groups of cycles were derived after the standardization to the maximum monthly value. Obtained values differed minimally, allowing us to derive a uniform distribution of activity for the entire review period from 1890 to 1996. The derived model of the distribution of activity in an average solar cycle allows us to predict the maximum value of an activity cycle with an advance of approximately 5 years based only on the value obtained in the first year of the cycle. This can be of use for, e.g., the planning of long-term human activities in outer space.

  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. Solar attitude control including active nutation damping in a fixed-momentum wheel satellite

    NASA Astrophysics Data System (ADS)

    Azor, Ruth

    1992-08-01

    In geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances, caused mainly by solar pressure. This work presents a roll/yaw control, which is obtained by the use of solar arrays and fixed flaps as actuators, with a horizon sensor for roll measurement. The design also includes an active nutation damping.

  14. Solar sail attitude control including active nutation damping in a fixed-momentum wheel satellite

    NASA Technical Reports Server (NTRS)

    Azor, Ruth

    1992-01-01

    In geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances, caused mainly by solar radiation pressure. This work presents a roll/yaw control which is obtained by the use of solar arrays and fixed flaps as actuators, with a horizon sensor for roll measurement. The design also includes an active nutation damping.

  15. Determining the solar wind speed above active regions using remote radio-wave observations.

    PubMed

    Bougeret, J L; Fainberg, J; Stone, R G

    1983-11-04

    A new technique has made it possible to measure the velocity of portions of the solar wind during its flow outward from the sun. This analysis utilizes spacecraft (ISEE-3) observations of radio emission generated in regions of the solar wind associated with solar active regions. By tracking the source of these radio waves over periods of days, it is possible to measure the motion of the emission regions. Evidence of solar wind acceleration during this outward flow, consistent with theoretical models, has also been obtained.

  16. F-Chart handbook. Active solar system sizing and economic analysis program

    NASA Astrophysics Data System (ADS)

    Mielke, G. W.

    1981-04-01

    The program is applicable to active solar space and service water heating systems that incorporate typical flat-plate solar collectors. The program is based on the F-Chart method of estimating annual system thermal performance. This program uses a standard life-cycle cost analysis methodology to calculate optimum solar system size and present economic performance data. The F-Chart program is designed to be used by anyone interested in, or involved with, solar heating systems. This handbook describes both information input requirements and the resultant thermal and economic analyses.

  17. Determining the solar wind speed above active regions using remote radio-wave observations

    NASA Technical Reports Server (NTRS)

    Fainberg, J.; Stone, R. G.; Bougeret, J.-L.

    1983-01-01

    A new technique has made it possible to measure the velocity of portions of the solar wind during its flow outward from the sun. This analysis utilizes spacecraft (ISEE-3) observations of radio emission generated in regions of the solar wind associated with solar active regions. By tracking the source of these radio waves over periods of days, it is possible to measure the motion of the emission regions. Evidence of solar wind acceleration during this outward flow, consistent with theoretical models, has also been obtained.

  18. 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.

  19. Organic solar cells: an overview focusing on active layer morphology.

    PubMed

    Benanti, Travis L; Venkataraman, D

    2006-01-01

    Solar cells constructed of organic materials are becoming increasingly efficient due to the discovery of the bulk heterojunction concept. This review provides an overview of organic solar cells. Topics covered include: a brief history of organic solar cell development; device construction, definitions, and characteristics; and heterojunction morphology and its relation to device efficiency in conjugated polymer/fullerene systems. The aim of this article is to show that researchers are developing a better understanding of how material structure relates to function and that they are applying this knowledge to build more efficient light-harvesting devices.

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

    NASA Astrophysics Data System (ADS)

    Scherer, K.; Fahr, H. J.

    2003-06-01

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

  1. Spectral analysis of auroral geomagnetic activity during various solar cycles between 1960 and 2014

    NASA Astrophysics Data System (ADS)

    Kotzé, Pieter Benjamin

    2016-12-01

    In this paper we use wavelets and Lomb-Scargle spectral analysis techniques to investigate the changing pattern of the different harmonics of the 27-day solar rotation period of the AE (auroral electrojet) index during various phases of different solar cycles between 1960 and 2014. Previous investigations have revealed that the solar minimum of cycles 23-24 exhibited strong 13.5- and 9.0-day recurrence in geomagnetic data in comparison to the usual dominant 27.0-day synodic solar rotation period. Daily mean AE indices are utilized to show how several harmonics of the 27-day recurrent period change during every solar cycle subject to a 95 % confidence rule by performing a wavelet analysis of each individual year's AE indices. Results show that particularly during the solar minimum of 23-24 during 2008 the 27-day period is no longer detectable above the 95 % confidence level. During this interval geomagnetic activity is now dominated by the second (13.5-day) and third (9.0-day) harmonics. A Pearson correlation analysis between AE and various spherical harmonic coefficients describing the solar magnetic field during each Carrington rotation period confirms that the solar dynamo has been dominated by an unusual combination of sectorial harmonic structure during 23-24, which can be responsible for the observed anomalously low solar activity. These findings clearly show that, during the unusual low-activity interval of 2008, auroral geomagnetic activity was predominantly driven by high-speed solar wind streams originating from multiple low-latitude coronal holes distributed at regular solar longitude intervals.

  2. New information on solar activity, 1779-1818, from Sir William Herschel's unpublished notebooks

    NASA Technical Reports Server (NTRS)

    Hoyt, Douglas V.; Schatten, Kenneth H.

    1992-01-01

    Herschel's observations are analyzed in order to determine the level of solar activity for solar cycle 5. It is concluded that solar cycle 5 may have peaked as early as 1801 based upon the average number of groups with a probable secondary maximum in 1804. Depending on the technique adopted, the peak for solar cycle 5 occurred sometime between 1801 and 1804, rather than 1805.2, as commonly assumed. Instead of a solar cycle of 17 yrs, a cycle length of 14 yrs is found. It is also found that the peak yearly mean sunspot number is only about 38 rather than 45, as deduced by Wolf (1855). A technique for making early solar observations homogeneous with modern sunspot observations is proposed.

  3. Program plan for reliability and maintainability in active solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    1980-10-01

    Specific objectives are as follows: provide all groups that have solar R & M concerns with the information that is available to the program and that can assist in alleviating those concerns; assist the solar energy industry in improving levels of R & M performance in state of the art solar energy systems, components, and materials; assist in the early development of a viable infrastructure for the design, manufacture, installation, and maintenance of reliable, maintainable, and durable solar energy systems; assist in the development of appropriate standards, code provisions, and certification programs relating to the R & M performance of solar energy systems, components, and materials; and develop the information required to support the other activities within the R & M program. These objectives correspond to five areas of action: regulations, research and development, technology transfer, solar industry infrastructure development, and data collection and analysis.

  4. Improving the performance of solar flare prediction using active longitudes information

    NASA Astrophysics Data System (ADS)

    Huang, X.; Zhang, L.; Wang, H.; Li, L.

    2013-01-01

    Context. Solar flare prediction models normally depend on properties of active regions, such as sunspot area, McIntosh classifications, Mount Wilson classifications, and various measures of the magnetic field. Nevertheless, the positional information of active regions has not been used. Aims: We define a metric, DARAL (distance between active regions and predicted active longitudes), to depict the positional relationship between active regions and predicted active longitudes and add DARAL to our solar flare prediction model to improve its performance. Methods: Combining DARAL with other solar magnetic field parameters, we build a solar flare prediction model with the instance-based learning method, which is a simple and effective algorithm in machine learning. We extracted 70 078 active region instances from the Solar and Heliospheric Observatory (SOHO)/Michelson Doppler Imager (MDI) magnetograms containing 1055 National Oceanic and Atmospheric Administration (NOAA) active regions within 30° of the solar disk center from 1996 to 2007 and used them to train and test the solar flare prediction model. Results: Using four performance measures (true positive rate, true negative rate, true skill statistic, and Heidke skill score), we compare performances of the solar flare prediction model with and without DARAL. True positive rate, true negative rate, true skill statistic, and Heidke skill score increase by 6.7% ± 1.3%, 4.2% ± 0.5%, 10.8% ± 1.4% and 8.7% ± 1.0%, respectively. Conclusions: The comparison indicates that the metric DARAL is beneficial to performances of the solar flare prediction model.

  5. Spatial Regularities of Solar Activity Effects in the Troposphere

    NASA Astrophysics Data System (ADS)

    Smirnov, R. V.

    1984-12-01

    Joint analysis of maps of density variations (or density dispersions) in the troposphere after geomagnetic disturbances and of maps of advection, wind velocity divergence, etc. makes it possible to put forward a concept of solar-induced centres of atmospheric action (SICA). Solar-disturbance transfer and planetary-wave development in the atmosphere are accomplished by means of SICA where the level of baroclinic instability is high. Infrasonic waves are considered as an agent connecting the lower thermosphere and the troposphere.

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

    NASA Astrophysics Data System (ADS)

    Shaltout, M.

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

  7. Solar wind quasi-invariant as a heliospheric index of solar activity

    NASA Astrophysics Data System (ADS)

    Fainberg, J.; Osherovich, V. A.

    2002-12-01

    Interplanetary magnetic field strength B, solar wind speed v and plasma density ρ all vary with sunspot numbers (SSN). The corresponding correlation coefficients (cc) are not high enough to establish any of these parameters as a close proxy for SSN. In contrast, the solar wind quasi-invariant [QI ≡ (B2/8π)/(ρv2/2)] recently suggested by Osherovich, Fainberg and Stone [1999] has a high cc = 0.98 for the median yearly value for the 28 year period measured in the solar wind near the Earth (1 AU). For the period 1978-1989, Voyager 2 measured B, v and ρ from 2 AU to 27 AU. In this paper we show that in spite of the orders of magnitude change of B and ρ at large heliospheric distances, QI measured by Voyager 2 stayed in the same range and followed SSN similar to QI measured near the Earth and near Venus. These results supply an observational test for any MHD model of the solar wind throughout the heliosphere that attempts to include the effects of solar cycle variability.

  8. National commercial solar heating and cooling demonstration: purposes, program activities, and implications for future programs

    SciTech Connect

    Koontz, R.; Genest, M.; Bryant, B.

    1980-05-01

    The Solar Heating and Cooling Demonstration Act of 1974 created a set of activities to demonstrate the potential use of solar heating within a three-year period and of combined solar heating and cooling within a five-year period. This study assesses the Commercial Demonstration Program portion of the activity in terms of its stated goals and objectives. The primary data base was DOE contractor reports on commercial demonstration projects. It was concluded that the program did not provide data to support a positive decision for the immediate construction or purchase of commercial solar systems. However, the program may have contributed to other goals in the subsequent legislation; i.e., research and development information, stimulation of the solar industry, and more informed policy decisions.

  9. A summary of recent activities at the National Solar Thermal Test Facility

    NASA Astrophysics Data System (ADS)

    Cameron, C. P.

    The United States Department of Energy's National Solar Thermal Test Facility (NSTTF), located at Sandia National Laboratories in Albuquerque, New Mexico, is the major facility for testing of solar thermal components and systems in the United States. Since originally being constructed as the Central Receiver Test Facility in the late 1970's, its mission has been expanded to include distributed receiver technologies, and it now includes line-focus and point-focus collectors, two solar furnaces, and an engine test facility. In addition, the unique capabilities of the facility have been applied to a wide variety of tests unrelated to solar energy, but using the intense heat from concentrated solar radiation or using the large-scale optical systems at the site. In this paper, current activities at the NSTTF are summarized, with an emphasis on activities that have not been described elsewhere.

  10. The Variation of Solar Fe 14 and Fe 10 Flux over 1.5 Solar Activity Cycles

    NASA Technical Reports Server (NTRS)

    Altrock, Richard C.

    1990-01-01

    A new source of data on the solar output, namely limb flux from the one- and two-million degree corona is presented. This parameter is derived from data obtained at the National Solar Observatory at Sacramento Peak with the 40 cm coronagraph of the John W. Evans Solar Facility and the Emission Line Coronal Photometer. The limb flux is defined to be the latitude-averaged intensity in millionths of the brightness of disk center from an annulus of width 1.1 minutes centered at a height of 0.15 solar constant above the limb of emission from lines at 6374A (Fe X) or 5303A (Fe XIV). Fe XIV data have been obtained since 1973 and Fe X since 1984. Examination of the Fe XIV data shows that there is ambiguity in the definition of the last two solar activity minima, which can affect the determination of cycle rise times and lengths. There is an indication that a constant minimum or basal corona may exist at solar minimum. Cycle 22 has had a much faster onset than Cycle 21 and has now overtaken Cycle 21. The rise characteristics of the two cycles were very similar up until Jul. to Aug. 1989, at which time a long-term maximum occurred in Fe X and Fe XIV, which could possibly be the solar maximum. Another maximum is developing at the current time. Cycle 21 was characterized in Fe XIV by at least 4 major thrusts or bursts of activity, each lasting on the order of a year and all having similar maximum limb fluxes which indicates that coronal energy output is sustained over periods in which the sunspot number declines significantly. Dramatic increases in the limb fluxes occur from minimum to maximum, ranging from factors of 14 to 21 in the two lines. Two different techniques to predict the epoch of solar maximum have been applied to the Fe XIV data, resulting in estimates of April 1989 (plus or minus 1 mo) and May 1990 (plus or minus 2 mos).

  11. 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.

  12. The Variability of Solar Spectral Irradiance and Solar Surface Indices Through the Solar Activity Cycles 21-23

    NASA Astrophysics Data System (ADS)

    Deniz Goker, Umit

    2016-07-01

    A study of variations of solar spectral irradiance (SSI) in the wavelength ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV) spectral lines and international sunspot number (ISSN) from interactive data centers as SME (NSSDC), UARS (GDAAC), SORCE (LISIRD) and SIDC, respectively. We developed a special software for extracting the data and reduced this data by using the MATLAB. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm) emission lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar cycles (SCs) 23 and 24. We also compared our results with the ground-based telescopes as Solar Irradiance Platform, Stanford Data (SFO), Kodaikanal Data (KKL) and NGDC Homepage (Rome and Learmonth Solar Observatories). We studied the variations of total solar irradiance (TSI), magnetic field, sunspots/sunspot groups, Ca II K-flux, faculae and plage areas data with these ground-based telescopes, respectively. We reduced the selected data using the Phyton programming language and plot with the IDL programme. Therefore, we found that there was a decrease in the area of bright faculae and chromospheric plages while the percentage of dark faculae and plage decrease, as well. However, these decreases mainly occurred in small sunspots, contrary to this, these terms in large sunspot groups were comparable to previous SCs or even larger. Nevertheless, negative correlations between ISSN and SSI data indicate that these emissions are in close connection with the classes of sunspots/sunspot groups and "PLAGE" regions. Finally, we applied the time series of the chemical elements correspond to the wavelengths 121.5 nm-300.5 nm and compared with the ISSN data. We found an unexpected increasing in the 298.5 nm for the Fe II element. The variability of Fe II (298.5 nm) is in close connection with the plage regions and the sizes of the

  13. Communist purges of Soviet Academy of Sciences members and solar activity

    NASA Astrophysics Data System (ADS)

    Tomilin, Konstantin A.

    The author is investigating the corelation between the intansity of Communsit purges under Members of the Academy of Sciences of USSR and Solar Activity, based on previous researches by Alexander Leonidovich Chizhevskij (1897-1964).

  14. Development and testing of heat transport fluids for use in active solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Parker, J. C.

    1981-01-01

    Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed.

  15. Statistical analysis of the relationships of solar, geomagnetic and human activities

    NASA Astrophysics Data System (ADS)

    Gil, Agnieszka; Alania, Michael; Modzelewska, Renata

    Data of galactic cosmic rays, solar and geomagnetic activities, solar wind parameters and car accident events (CAE) in Poland have been analyzed in order to reveal the statistical relationships among them for the period of 1990- 2007. Cross correlation, cross spectrum and filters method have been used to analyze data of the galactic cosmic ray intensity, the solar wind (SW) velocity, DST, Kp index of geomagnetic activity and CAE in Poland. For some epochs of the above-mentioned period there is found a consistent relationship between CAE, parameters of solar and geomagnetic activities in various periodicities; e.g. the periodicity of 7 days is clearly revealed in CAE, in galactic cosmic rays, SW, solar and geomagnetic activities, especially for the minimum epoch of solar activity. We suppose that there is not excluded that the 7 day periodicity is partially related with the human social activities. The periodicity of 3.5 days, generally found only in the series of CAE data, more or less should be ascribed to the social activities, besides we have not an explicit physical-biological explanation of this effect.

  16. ON MAGNETIC ACTIVITY BAND OVERLAP, INTERACTION, AND THE FORMATION OF COMPLEX SOLAR ACTIVE REGIONS

    SciTech Connect

    McIntosh, Scott W.; Leamon, Robert J.

    2014-11-20

    Recent work has revealed a phenomenological picture of the how the ∼11 yr sunspot cycle of the Sun arises. The production and destruction of sunspots is a consequence of the latitudinal-temporal overlap and interaction of the toroidal magnetic flux systems that belong to the 22 yr magnetic activity cycle and are rooted deep in the Sun's convective interior. We present a conceptually simple extension of this work, presenting a hypothesis on how complex active regions can form as a direct consequence of the intra- and extra-hemispheric interaction taking place in the solar interior. Furthermore, during specific portions of the sunspot cycle, we anticipate that those complex active regions may be particularly susceptible to profoundly catastrophic breakdown, producing flares and coronal mass ejections of the most severe magnitude.

  17. Solar geomagnetic activity prediction using the fractal analysis and neural network

    NASA Astrophysics Data System (ADS)

    Ouadfeul, Sid-Ali; Aliouane, Leila

    2010-05-01

    The main goal of this work is to predict the Solar geomagnetic field activity using the neural network combined with the fractal analysis, first a multilayer perceptron neural network model is proposed to predict the future Solar geomagnetic field, the input of this machine is the geographic Coordinates and the time .The output is the three geomagnetic field components and the total field intensity recorded by the Orsted Satellite Mission. Holder Exponents of the measured geomagnetic field components and the total field intensity are calculated using the continuous wavelet transform. The Set of Holder exponents is used to train a Kohonen's Self-Organizing Map (SOM) neural machine which will become a classifier of the solar magnetic activity nature. The SOM neural network machine is used to predict the future solar magnetic storms, in this step the input is the calculated set of the Holder exponents of the predicted geomagnetic field components and the total field intensity. Obtained results show that the proposed technique is a powerful tool and can enhance the solar magnetic field activity prediction. Keywords: Solar geomagnetic activity, neural network, prediction, Orsted, Holder Exponents, Solar magnetic storms.

  18. RESEARCH PAPER: A logistic model for magnetic energy storage in solar active regions

    NASA Astrophysics Data System (ADS)

    Wang, Hua-Ning; Cui, Yan-Mei; He, Han

    2009-06-01

    Previous statistical analyses of a large number of SOHO/MDI full disk longitudinal magnetograms provided a result that demonstrated how responses of solar flares to photospheric magnetic properties can be fitted with sigmoid functions. A logistic model reveals that these fitted sigmoid functions might be related to the free energy storage process in solar active regions. Although this suggested model is rather simple, the free energy level of active regions can be estimated and the probability of a solar flare with importance over a threshold can be forecast within a given time window.

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

    SciTech Connect

    Menicucci, D.F.

    1994-03-01

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

  20. Energy deposition in the earth's atmosphere due to impact of solar activity-generated disturbances

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Kan, L. C.; Tandberg-Hanssen, E.; Dryer, M.

    1979-01-01

    Energy deposition in and dynamic responses of the terrestrial atmosphere to solar flare-generated shocks and other physical processes - such as particle precipitation and local heating - are investigated self-consistently in the context of hydrodynamics, the problem being treated as an initial boundary-value problem. It is extremely difficult to construct a general model for the line solar activity-magnetosphere-atmosphere; however, a limited model for this link is possible. The paper describes such a model, and presents some results on energy deposition into the earth's atmosphere due to solar activity-generated disturbances. Results from the present calculations are presented and discussed.

  1. Recent National Solar Thermal Test Facility activities, in partnership with industry

    SciTech Connect

    Ghanbari, C.; Cameron, C.P.; Ralph, M.E.; Pacheco, J.E.; Rawlinson, K.S.; Evans, L.R.

    1994-10-01

    The National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories in Albuquerque, New Mexico, USA conducts testing of solar thermal components and systems, funded primarily by the US Department of Energy. Activities are conducted in support of Central Receiver Technology, Distributed Receiver Technology and Design Assistance projects. All activities are performed in support of various cost-shared government/industry joint ventures and, on a design assistance basis, in support of a number of other industry partners.

  2. Helioseismology: A probe of the solar interior, atmosphere, and activity cycle

    NASA Technical Reports Server (NTRS)

    Rhodes, E. J., Jr.

    1995-01-01

    Helioseismology began in earnest in the mid 1970's. In the two decades which have elapsed since that time this branch of solar physics has become a mature field of research. Helioseismology has demonstrated that the solar convection zone is about twice as deep as was generally thought to be the case before 1977. Helioseismology has also provided measurements of the solar internal angular velocity over much of the sun's interior. Helioseismology has also ruled out models which would solve the solar neutrino problem by a lowering of the temperature of the core. Recently, some of the seismic properties of the sun have been demonstrated to vary with changing levels of solar activity. Also, helioseismology has recently provided evidence for helical flow patterns in the shallow, sub-photosphere layers. The techniques of helioseismology are also expanding to include seismic probes of solar active regions. Some work is also being conducted into the possible contributions of the solar acoustic models to the heating of the solar atmosphere. In this talk I will highlight a few of the above results and concentrate on current areas of research in the field.

  3. Solar Spectral Irradiance Variability of Some Chromospheric Emission Lines Through the Solar Activity Cycles 21-23

    NASA Astrophysics Data System (ADS)

    Göker, Ü. D.; Gigolashvili, M. Sh.; Kapanadze, N.

    2017-02-01

    A study of variations of solar spectral irradiance (SSI) in the wavelength ranges 121.5 nm-300.5 nm for the period 1981-2009 is presented. We used various data for ultraviolet (UV) spectral lines and international sunspot number (ISSN) from interactive data centers such as SME (NSSDC), UARS (GDAAC), SORCE (LISIRD) and SIDC, respectively. We reduced these data by using the MATLAB software package. In this respect, we revealed negative correlations of intensities of UV (289.5 nm-300.5 nm) spectral lines originating in the solar chromosphere with the ISSN index during the unusually prolonged minimum between the solar activity cycles (SACs) 23 and 24. We also compared our results with the variations of solar activity indices obtained by the ground-based telescopes. Therefore, we found that plage regions decrease while facular areas are increasing in SAC 23. However, the decrease in plage regions is seen in small sunspot groups (SGs), contrary to this, these regions in large SGs are comparable to previous SACs or even larger as is also seen in facular areas. Nevertheless, negative correlations between ISSN and SSI data indicate that these variations are in close connection with the classes of sunspots/SGs, faculae and plage regions. Finally, we applied the time series analysis of spectral lines corresponding to the wavelengths 121.5 nm-300.5 nm and made comparisons with the ISSN data. We found an unexpected increase in the 298.5 nm line for the Fe II ion. The variability of Fe II ion 298.5 nm line is in close connection with the facular areas and plage regions, and the sizes of these solar surface indices play an important role for the SSI variability, as well. So, we compared the connection between the sizes of faculae and plage regions, sunspots/SGs, chemical elements and SSI variability. Our future work will be the theoretical study of this connection and developing of a corresponding model.

  4. Seasonal and solar activity changes of electron temperature in the F-region and topside ionosphere

    NASA Astrophysics Data System (ADS)

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

    Incoherent scatter radar data from Arecibo, for high solar activity (HSA) (1989-1990) as well as for low solar activity (LSA) (1974-1977) periods, are used to study the seasonal and solar activity variations in electron temperature (Te) for noontime conditions. Inspite of large day-to-day variations, clear seasonal variations in average Te can be identified for both solar activity periods, with winter temperatures significantly higher in the topside (400-700 km) ionosphere. Further, comparison of average Te profiles for each season reveals distinct solar activity variations - a large increase in the F-region (200-350 km) Te, during summer and equinox as compared to winter, occurs as one moves from low to HSA. In the topside, however, electron temperature changes little with solar activity. Comparisons with IRI-95 and Truhlik et al. (2000) models show a reasonable agreement within one standard deviation of the measured values.

  5. Understanding Measures of Magnetic Activity Using Physics-based Models of the Solar Interior and Atmosphere

    NASA Astrophysics Data System (ADS)

    Abbett, W. P.; Luhmann, J. G.

    2014-12-01

    Substantial progress has been made over the past decade in the effort to better understand how magnetic flux and energy is generated in the convective interior of the Sun, how it emerges into the solar atmosphere, and how manifestations of solar magnetic activity (such as sunspots, coronal mass ejections, and flares) are connected within a dynamic magnetic environment spanning the solar convection zone-to-corona system. Here, we present a brief overview of recent efforts to model the evolution of active region magnetic fields and sunspots over a range of physical conditions and spatial and temporal scales. We will focus on how dynamic, physics-based numerical models can be used to better understand observed relationships between different measures of solar activity as a function of time (e.g., sunspot activity and morphologies, unsigned magnetic flux measured at the photosphere, coronal X-ray emissivity). We will determine whether local physics-based models of active region evolution can be used to better constrain proxies of solar activity such as the sunspot number, which remains the only direct record available to trace the very long-term influence of the solar dynamo on the earth's environment.

  6. Solar activity dependence of low-and mid-latitude ionosphere

    NASA Astrophysics Data System (ADS)

    Chen, Yiding; Liu, Libo; Wan, Weixing

    Solar activity dependence of low-and mid-latitude ionosphere is investigated using ionosonde and the ROCSAT-1 satellite (600 km) observations. The pattern in the solar activity varia-tion of the electron density shows significant local time, seasonal, latitudinal, and altitudinal dependences. Noontime NmF2 saturates with F107 in all seasons in low-latitude regions, while it saturates with F107 in equinoxes and local summer and linearly increases with F107 in local winter in mid-latitude regions. Nighttime NmF2 nearly increases with F107 linearly in equinox seasons and saturates with F107 in local summer, what is peculiar is that there is an amplifica-tion trend of nighttime NmF2 with F107 in local winter. We discussed the possible mechanisms which affect the solar activity variation trend of NmF2 and argued that the changes of neutral atmosphere and ionospheric dynamics are important for the solar activity variation trend of NmF2. Solar activity variations of the plasma density at 600 km present three kinds of patterns (linearity, amplification, and saturation), the pattern depends on local time, season, and lati-tude. That is different from the case at higher altitudes, e.g., 800 km, where the amplification trend prevails. In particular, saturation effect is found in the dip equator region at equinox sunset. Latitudinal distribution of the plasma density at 600 km also depends on local time, season, and solar activity level. Around sunset, a profound double-peak structure is found in the latitudinal distribution of the plasma density in solar maximum equinox and December solstice months. Solar activity dependence of the low-latitude topside ionosphere at 600 km is strongly related to the low-latitude dynamics processes.

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

    NASA Astrophysics Data System (ADS)

    Panayiotis Zois, Ioannis

    2013-11-01

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

  8. Active Control of Solar Array Dynamics During Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

    2016-01-01

    Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

  9. Two principal components of solar magnetic field variations and prediction of solar activity on multi-millennium timescale

    NASA Astrophysics Data System (ADS)

    Zharkova, Valentina; Popova, Helen; Zharkov, Sergei; Shepherd, Simon

    2016-07-01

    We present principal components analysis (PCA) of temporal magnetic field variations over the solar cycles 21-24 and their classification with symbolic regression analysis using Hamiltonian method. PCA reveals 4 pairs of magnetic waves with a significant variance and the two principal components with the highest eigen values covering about 40% of this variance. The PC waves are found to have close frequencies while travelling from the opposite hemispheres with an increasing phase shift. Extrapolation of these PCs through their summary curve backward for 5000 years reveals a repeated number of ~350-400 year grand cycles superimposed on 22 year-cycles with the features showing a remarkable resemblance to sunspot activity reported in the past including Maunder, Dalton and Wolf minima, as well as the modern, medieval and roman warmth periods. The summary curve calculated forward for the next millennium predicts further three grand cycles with the closest grand minimum (Maunder minimum) occurring in the forthcoming cycles 25-27 when the two magnetic field waves approach the phase shift of 11 years. We also note a super-grand cycle of about 2000 years which reveal the 5 repeated grand cycles of 350 years with the similar patterns. We discuss a role of other 3 pairs of magnetic waves in shaping the solar activity and compare our predicted curve with the previous predictions of the solar activity on a long timescale based on the terrestrial proxies. These grand cycle variations are probed by Parker's two layer dynamo model with meridional circulation revealing two dynamo waves generated with close frequencies. Their interaction leads to beating effects responsible for the grand cycles (300-350 years) and super-grand cycles of 2000 years superimposed on standard 22 year cycles. This approach opens a new era in investigation and prediction of solar activity on long-term timescales.

  10. 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.

  11. 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.

  12. Signatures of Slow Solar Wind Streams from Active Regions in the Inner Corona

    NASA Astrophysics Data System (ADS)

    Slemzin, V.; Harra, L.; Urnov, A.; Kuzin, S.; Goryaev, F.; Berghmans, D.

    2013-08-01

    The identification of solar-wind sources is an important question in solar physics. The existing solar-wind models ( e.g., the Wang-Sheeley-Arge model) provide the approximate locations of the solar wind sources based on magnetic field extrapolations. It has been suggested recently that plasma outflows observed at the edges of active regions may be a source of the slow solar wind. To explore this we analyze an isolated active region (AR) adjacent to small coronal hole (CH) in July/August 2009. On 1 August, Hinode/EUV Imaging Spectrometer observations showed two compact outflow regions in the corona. Coronal rays were observed above the active-region coronal hole (ARCH) region on the eastern limb on 31 July by STEREO-A/EUVI and at the western limb on 7 August by CORONAS- Photon/TESIS telescopes. In both cases the coronal rays were co-aligned with open magnetic-field lines given by the potential field source surface model, which expanded into the streamer. The solar-wind parameters measured by STEREO-B, ACE, Wind, and STEREO-A confirmed the identification of the ARCH as a source region of the slow solar wind. The results of the study support the suggestion that coronal rays can represent signatures of outflows from ARs propagating in the inner corona along open field lines into the heliosphere.

  13. Decadal variability of European sea level extremes in relation to the solar activity

    NASA Astrophysics Data System (ADS)

    Martínez-Asensio, Adrián.; Tsimplis, Michael N.; Calafat, Francisco Mir

    2016-11-01

    This study investigates the relationship between decadal changes in solar activity and sea level extremes along the European coasts and derived from tide gauge data. Autumn sea level extremes vary with the 11 year solar cycle at Venice as suggested by previous studies, but a similar link is also found at Trieste. In addition, a solar signal in winter sea level extremes is also found at Venice, Trieste, Marseille, Ceuta, Brest, and Newlyn. The influence of the solar cycle is also evident in the sea level extremes derived from a barotropic model with spatial patterns that are consistent with the correlations obtained at the tide gauges. This agreement indicates that the link to the solar cycle is through modulation of the atmospheric forcing. The only atmospheric regional pattern that showed variability at the 11 year period was the East Atlantic pattern.

  14. THE ACOUSTIC CUTOFF FREQUENCY OF THE SUN AND THE SOLAR MAGNETIC ACTIVITY CYCLE

    SciTech Connect

    Jimenez, A.; Palle, P. L.; Garcia, R. A.

    2011-12-20

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

  15. Variations in Solar Activity and Irradiance and Their Implications for Energy Input Into the Terrestrial Atmosphere

    NASA Astrophysics Data System (ADS)

    Parker, Daryl Gray

    accuracy many of the different wavelengths comprising solar irradiance and to identify the features producing them on the solar surface. The results of this research imply constraints on the fraction of variations in solar TSI and other wavelength emissions which can be accounted for by magnetic field variations without resort to other explanatory mechanisms. These findings in turn imply constraints on the extent to which variations in solar irradiance may be a factor contributing to observed global warming. These findings include: (1) constraining possible non-magnetic sources of TSI variations to a range of 5--6% versus 10--20% in earlier research, suggesting a limitation on solar TSI forcing of terrestrial climate to the 0.1% solar cycle variations in magnetic activity and (2) a failure to find an upward minimum to minimum trend in TSI from Cycle 21/22 to 22/23 such as reported by others and the detection of a downward trend from the Cycle 22/23 to 23/24 minimum. The results are also useful diagnostics for the inference of the surface properties study of solar-type stars for which resolved spatial images are not available.

  16. Radiation From Solar Activity | Radiation Protection | US EPA

    EPA Pesticide Factsheets

    2016-05-18

    Solar flares, coronal mass ejections (CMEs) and geomagnetic storms from the sun can send extreme bursts of ionizing radiation and magnetic energy toward Earth. Some of this energy is in the form ionizing radiation and some of the energy is magnetic energy.

  17. The SSRT in the 23rd Cycle of Solar Activity

    NASA Astrophysics Data System (ADS)

    Zandanov, V. G.; Altyntsev, A. T.; Lesovoi, S. V.

    1999-12-01

    We present a sketch of the project to upgrade the Siberian Solar Radio Telescope. We suggest expanding the spectral range of receiving frequencies from a single frequency (5.7~GHz) to five frequencies and to considerably improve the sensitivity of instrument.

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

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

    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 (stormy) 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.

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

    NASA Technical Reports Server (NTRS)

    Lang, K. R.

    1986-01-01

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

  20. 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.

  1. 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)

    2001-01-01

    We have continued in collaboration with Dr. Eff-Darwich (University of La Laguna, Tenerife, Spain) the study of the structure, asphericity and dynamics of the solar interior from p-mode frequencies and frequency splittings. In March 2001, Dr. Eff-Darwich came for 3 weeks visit to CfA. During this visit we completed our work on the inversion of the internal solar rotation rate, and submitted a paper describing this work to the Astrophysical Journal. This paper has been recently revised in response to the referee comments and I expect that it will be accepted for publication very soon. We also have analyzed helioseismic data looking for temporal variations of the solar stratification near the base of the convection zone. We have expanded on the initial work that was presented at the SOHO-10/GONG-2000 meeting (October 2000, Tenerife), and are in the process of writing this up. Substantial progress towards the characterization of high-degree p-modes has been achieved. Indeed, in collaboration Dr. Rabello-Soares (Stanford University), we have gained a clear conceptual understanding of the various elements that affect the leakage matrix of the SOI/MDI instrument. This was presented in an invited talk at the SOHO-10/GONG-2000 meeting (October 2000, Tenerife). Once we will have successfully migrated from a qualitative to a quantitative assessment of these effects, we should be able to generate high-degree p-modes frequencies so crucial in the diagnostic of the layers just below solar surface.

  2. Radiation environment due to galactic and solar cosmic rays during manned mission to Mars in the periods between maximum and minimum solar activity cycles.

    PubMed

    Pissarenko, N F

    1994-10-01

    A possibility of a manned mission to Mars without exceeding the current radiation standards is very doubtful during the periods of minimum solar activity since the dose equivalent due to galactic cosmic rays exceeds currently recommended standards even inside a radiation shelter with an equivalent of 30 g cm-2 aluminum. The radiation situation at the time of maximum solar activity is determined by the occurrence of major solar proton events which are exceedingly difficult to forecast. This paper discusses the radiation environment during a manned mission to Mars in the years between minimum and maximum solar activity when the galactic cosmic ray intensity is considerably reduced, but the solar flare activity has not yet maximized.

  3. Solar activity prediction of sunspot numbers (verification). Predicted solar radio flux; predicted geomagnetic indices Ap and Kp. [space shuttle program: satellite orbital lifetime

    NASA Technical Reports Server (NTRS)

    Newman, S. R.

    1980-01-01

    Efforts to further verify a previously reported technique for predicting monthly sunspot numbers over a period of years (1979 to 1989) involved the application of the technique over the period for the maximum epoch of solar cycle 19. Results obtained are presented. Methods and results for predicting solar flux (F10.7 cm) based on flux/sunspot number models, ascent and descent, and geomagnetic activity indices as a function of sunspot number and solar cycle phase classes are included.

  4. 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.

  5. Ionospheric response to sudden stratospheric warming events at low and high solar activity

    NASA Astrophysics Data System (ADS)

    Fang, Tzu-Wei; Fuller-Rowell, Tim; Wang, Houjun; Akmaev, Rashid; Wu, Fei

    2014-09-01

    The sensitivity of the ionospheric response to a sudden stratospheric warming (SSW) event has been examined under conditions of low and high solar activity through simulations using the whole atmosphere model (WAM) and the global ionosphere plasmasphere model (GIP). During non-SSW conditions, simulated daytime mean vertical drifts at the magnetic equator show similar solar activity dependence as an empirical model. Model results of ionospheric total electron content (TEC) and equatorial vertical drift for the January 2009 major SSW, which occurred at very low solar activity conditions, show reasonable agreement with observations. The simulations demonstrate that the E region dynamo is capable of creating the semidiurnal variation of vertical drift. WAM and GIP were also run at high solar activity conditions, using the same lower atmosphere conditions as present in the January 2009 SSW event. The simulations indicate that the amplitude and phase of migrating tides in the dynamo region during the event have similar magnitudes for both solar flux conditions. However, comparing the ionospheric responses to a major SSW under low and high solar activity periods, it was found that the changes in the ionospheric vertical drifts and relative changes in TEC decreased with increasing solar activity. The simulations indicate that the F region dynamo becomes more important throughout the daytime and contributes to the upward drift in the afternoon during the event when the solar activity is higher. Our test simulations also confirm that the increase of the ionospheric conductivity associated with increasing solar activity is responsible for the decrease of vertical drift changes during an SSW. In particular, first, the increase in F region conductivity allows the closure of E region currents through the F region, reducing the polarization electric field before noon. Second, the F region dynamo contributes an upward drift postnoon, maintaining upward drifts till after sunset

  6. Geomagnetic activity during 10 - 11 solar cycles that has been observed by old Russian observatories.

    NASA Astrophysics Data System (ADS)

    Seredyn, Tomasz; Wysokinski, Arkadiusz; Kobylinski, Zbigniew; Bialy, Jerzy

    2016-07-01

    A good knowledge of solar-terrestrial relations during past solar activity cycles could give the appropriate tools for a correct space weather forecast. The paper focuses on the analysis of the historical collections of the ground based magnetic observations and their operational indices from the period of two sunspot solar cycles 10 - 11, period 1856 - 1878 (Bartels rotations 324 - 635). We use hourly observations of H and D geomagnetic field components registered at Russian stations: St. Petersburg - Pavlovsk, Barnaul, Ekaterinburg, Nertshinsk, Sitka, and compare them to the data obtained from the Helsinki observatory. We compare directly these records and also calculated from the data of the every above mentioned station IHV indices introduced by Svalgaard (2003), which have been used for further comparisons in epochs of assumed different polarity of the heliospheric magnetic field. We used also local index C9 derived by Zosimovich (1981) from St. Petersburg - Pavlovsk data. Solar activity is represented by sunspot numbers. The correlative and continuous wavelet analyses are applied for estimation of the correctness of records from different magnetic stations. We have specially regard to magnetic storms in the investigated period and the special Carrington event of 1-2 Sep 1859. Generally studied magnetic time series correctly show variability of the geomagnetic activity. Geomagnetic activity presents some delay in relation to solar one as it is seen especially during descending and minimum phase of the even 11-year cycle. This pattern looks similarly in the case of 16 - 17 solar cycles.

  7. Diagnostics of a cause-effect relation between solar activity and the Earth's global surface temperature

    NASA Astrophysics Data System (ADS)

    Mokhov, I. I.; Smirnov, D. A.

    2008-06-01

    The influence of solar activity on the Earth’s global surface temperature (GST) was quantified. The method for estimation of the Granger causality was used, with analysis of the improvement of the prediction of one process by using data from another process as compared to autoprediction. Two versions of reconstructions of the solar flux variations associated with solar activity were used, according to Hoyt et al. [1997] for 1680 1992 (data H) and according to Lean et al. [2005] for 1610 2005 (data L). In general, the estimation results for the two reconstructions are reasonably well consistent. A significant influence of solar activity on GST with a positive sign was found for two periods, from the late 19th century to the late 1930s and from the latter half of the 1940s to the early 1990s, with no inertia or time delay. In these periods, up to 8 and 25% of the variance of the GST change, respectively, can be attributed to solar activity variations. The solar influence increased in the 1980s to the early 1990s according to data H and began to decrease in the latter half of the 1980s according to data L.

  8. Nonlinear Dynamics of Magnetohydrodynamic Rossby Waves and the Cyclic Nature of Solar Magnetic Activity

    NASA Astrophysics Data System (ADS)

    Raphaldini, Breno; Raupp, Carlos F. M.

    2015-01-01

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

  9. 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.

  10. Variability of the Lyman alpha flux with solar activity

    SciTech Connect

    Lean, J.L.; Skumanich, A.

    1983-07-01

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

  11. Deep Solar Activity Minimum 2007-2009: Solar Wind Properties and Major Effects on the Terrestrial Magnetosphere

    NASA Astrophysics Data System (ADS)

    Farrugia, C. J.; Harris, B.; Leitner, M.; Möstl, C.; Galvin, A. B.; Simunac, K. D. C.; Torbert, R. B.; Temmer, M. B.; Veronig, A. M.; Erkaev, N. V.; Szabo, A.; Ogilvie, K. W.; Luhmann, J. G.; Osherovich, V. A.

    2012-04-01

    We discuss the temporal variations and frequency distributions of solar wind and interplanetary magnetic field parameters during the solar minimum of 2007- 2009 from measurements returned by the IMPACT and PLASTIC instruments on STEREO-A. We find that the density and total field strength were considerably weaker than in the previous minimum. The Alfvén Mach number was higher than typical. This reflects the weakness of magnetohydrodynamic (MHD) forces, and has a direct effect on the solar wind-magnetosphere interactions. We then discuss two major aspects that this weak solar activity had on the magnetosphere using data from Wind and ground-based observations: (a) the level of solar wind driving and the associated dayside contribution to the crosspolar cap potential (CPCP), and (b) the shapes of the magnetopause and bow shock. For (a) we find very weak interplanetary electric field (V xBz = -0.05 ± 0.83 mV/m) and a CPCP of 36.6 ± 18.2 kV. The auroral activity is closely correlated to the prevalent stream-stream interactions.We argue that the Alfvén waves in the fast streams and Kelvin-Helmholtz instability were the predominant agents mediating the transfer of solar wind momentum and energy to the magnetosphere during this 3-year period. For (b) we determine 328 magnetopause and 271 bow shock crossings made by the Cluster 1, Themis B and C spacecraft during a 3-month interval when the daily averages of the magnetic and kinetic energy densities attained their lowest value during the 3 years under survey. We use the same numerical approach as in Fairfield's (1971) empirical model and compare our findings with his classic result. The stand-off distance of the subsolar magnetopause and bow shock were 11.8 RE and 14.35 RE, respectively, making the subsolar magnetosheath thinner by ≈ 1RE. This is mainly due to the low dynamic pressure which result in a sunward shift of the magnetopause The magnetopause is more flared than Fairfield's result. By contrast the bow shock

  12. Future missions studies: Combining Schatten's solar activity prediction model with a chaotic prediction model

    NASA Technical Reports Server (NTRS)

    Ashrafi, S.

    1991-01-01

    K. Schatten (1991) recently developed a method for combining his prediction model with our chaotic model. The philosophy behind this combined model and his method of combination is explained. Because the Schatten solar prediction model (KS) uses a dynamo to mimic solar dynamics, accurate prediction is limited to long-term solar behavior (10 to 20 years). The Chaotic prediction model (SA) uses the recently developed techniques of nonlinear dynamics to predict solar activity. It can be used to predict activity only up to the horizon. In theory, the chaotic prediction should be several orders of magnitude better than statistical predictions up to that horizon; beyond the horizon, chaotic predictions would theoretically be just as good as statistical predictions. Therefore, chaos theory puts a fundamental limit on predictability.

  13. Energetic analysis of the white light emission associated to seismically active flares in solar cycle 24

    NASA Astrophysics Data System (ADS)

    Buitrago-Casas, Juan Camilo; Martinez Oliveros, Juan Carlos; Glesener, Lindsay; Krucker, Sam

    2014-06-01

    Solar flares are explosive phenomena, thought to be driven by magnetic free energy accumulated in the solar corona. Some flares release seismic transients, "sunquakes", into the Sun's interior. Different mechanisms are being considered to explain how sunquakes are generated. We are conducting an analysis of white-light emission associated with those seismically active solar flares that have been reported by different authors within the current solar cycle. Seismic diagnostics are based upon standard time-distance techniques, including seismic holography, applied to Dopplergrams obtained by SDO/HMI and GONG. The relation between white-light emissions and seismic activity may provide important information on impulsive chromospheric heating during flares, a prospective contributor to seismic transient emission, at least in some instances. We develop a method to get an estimation of Energy associated whit white-light emission and compare those results whit values of energy needed to generate a sunquake according with holographic helioseismology techniques.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  15. Chromospheric activity and ages of solar-type stars

    SciTech Connect

    Barry, D.C.; Cromwell, R.H.; Hege, E.K.

    1987-04-01

    Observations of 15 solar-type stars in the intermediate-age open cluster NGC 752 are reported. A lower resolution analog of the Mount Wilson S index is shown to yield absolute chromospheric surface flux values for these stars with about 60 percent of the sensitivity of the Mount Wilson system. Absolute chromospheric surface fluxes of solar-type stars in eight clusters ranging from 10 million yrs to six billion or more years in age are presented. Two heuristic forms are shown to fit the data about equally well, with no indication of a discontinuity at intermediate ages. These relations can yield chromospheric ages for any G-type dwarf or subgiant with a Mount Wilson S index. The usefulness of this lower resolution approach for studies of chemical and dynamical evolution of the Galaxy as well as of the stellar birth rate is pointed out. 24 references.

  16. Active Solar Energy System Design, Installation and Maintenance Manual.

    DTIC Science & Technology

    1986-04-01

    material choice that meets these requirements is ethylene- propylene-diene-monomer ( EPDM ) rubber. Ease of installation is the second item to be considered...allowing a single thermometer to be moved from row to row for testing . * The thermometer should be Installed Initially on the same row - as the collector...require the flushing and pressure testing of the solar system piping. 7. Define responsibility for coordination of the contractor’s work. 8. Operational

  17. Solar sail attitude control including active nutation damping in a fixed-momentum wheel satellite

    NASA Astrophysics Data System (ADS)

    Azor, Ruth

    1992-02-01

    In the geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances caused by solar radiation pressure. This work presents a roll/yaw control system with a horizon sensor for roll measurement. Roll/yaw control is obtained by the use of solar arrays and fixed flaps as actuators. The design also includes an active nutation damping method.

  18. Recombination-active defects in silicon ribbon and polycrystalline solar cells

    NASA Technical Reports Server (NTRS)

    Cheng, L. J.

    1984-01-01

    This paper reports results from a study of recombination-active structural defects in silicon ribbon and polycrystalline solar cells using the electron beam induced current (EBIC) technique in a scanning electron microscope. It is demonstrated that low temperature EBIC measurements can reveal a range of defects that are not observable at room temperature, including slip dislocations in silicon dendritic web ribbons as well as decorated twin boundaries and dislocation complexes in cast polycrystalline silicon solar cell materials.

  19. Impact of variations in solar activity on hydrological decadal patterns in northern Italy

    NASA Astrophysics Data System (ADS)

    Zanchettin, D.; Rubino, A.; Traverso, P.; Tomasino, M.

    2008-06-01

    Using spectral and statistical analyses of discharges and basin average precipitation rates acquired over the Po River since the early 1800s, we investigate the impact of variations in solar activity on hydrological decadal patterns over northern Italy. Wet and dry periods appear to alternate in accordance with polarized sunspot cycles. Intriguingly, a solar signature on Po River discharges is detected to be highly significant since the late 1800s, before the onset of sunspots hyperactivity established by the middle 1900s. In particular, observed hydrological patterns over northern Italy are significantly correlated, under periods of quiet sunspot activity, with parameters characterizing the Sun's orbital motion, specifically with the time derivative of the solar angular momentum (τ) which is thought to modulate the strength of the solar wind and sunspot dynamics under weak sunspot activity. The North Atlantic Oscillation (NAO) is detected as potential link between the Sun and Po River discharges, since it is significantly correlated with both solar activity and the decadal variability in the north Italian climate. In particular, positive (negative) NAO anomalies, which are associated with comparatively lower (higher) Po River discharges, are assessed to alternatively correlate at decadal timescales either with τ or with the Earth's geomagnetic activity (GA), which closely follows sunspot activity. This changing correlation seems to be regulated by the strength of sunspot activity: under periods of quiet sunspot activity, a weakening of the GA-NAO connection and a reinforcement of the τ-NAO connection is observed. In this sense, the strength of solar activity apparently modulates the connection between the NAO and Po River discharges.

  20. Effect of solar activity on the repetitiveness of some meteorological phenomena

    NASA Astrophysics Data System (ADS)

    Todorović, Nedeljko; Vujović, Dragana

    2014-12-01

    In this paper we research the relationship between solar activity and the weather on Earth. This research is based on the assumption that every ejection of magnetic field energy and particles from the Sun (also known as Solar wind) has direct effects on the Earth's weather. The impact of coronal holes and active regions on cold air advection (cold fronts, precipitation, and temperature decrease on the surface and higher layers) in the Belgrade region (Serbia) was analyzed. Some active regions and coronal holes appear to be in a geo-effective position nearly every 27 days, which is the duration of a solar rotation. A similar period of repetitiveness (27-29 days) of the passage of the cold front, and maximum and minimum temperatures measured at surface and at levels of 850 and 500 hPa were detected. We found that 10-12 days after Solar wind velocity starts significantly increasing, we could expect the passage of a cold front. After eight days, the maximum temperatures in the Belgrade region are measured, and it was found that their minimum values appear after 12-16 days. The maximum amount of precipitation occurs 14 days after Solar wind is observed. A recurring period of nearly 27 days of different phases of development for hurricanes Katrina, Rita and Wilma was found. This analysis confirmed that the intervals of time between two occurrences of some particular meteorological parameter correlate well with Solar wind and A index.

  1. On dependence of seismic activity on 11 year variations in solar activity and/or cosmic rays

    NASA Astrophysics Data System (ADS)

    Zhantayev, Zhumabek; Khachikyan, Galina; Breusov, Nikolay

    2014-05-01

    It is found in the last decades that seismic activity of the Earth has a tendency to increase with decreasing solar activity (increasing cosmic rays). A good example of this effect may be the growing number of catastrophic earthquakes in the recent rather long solar minimum. Such results support idea on existence a solar-lithosphere relationship which, no doubts, is a part of total pattern of solar-terrestrial relationships. The physical mechanism of solar-terrestrial relationships is not developed yet. It is believed at present that one of the main contenders for such mechanism may be the global electric circuit (GEC) - vertical current loops, piercing and electrodynamically coupling all geospheres. It is also believed, that the upper boundary of the GEC is located at the magnetopause, where magnetic field of the solar wind reconnects with the geomagnetic field, that results in penetrating solar wind energy into the earth's environment. The effectiveness of the GEC operation depends on intensity of cosmic rays (CR), which ionize the air in the middle atmosphere and provide its conductivity. In connection with the foregoing, it can be expected: i) quantitatively, an increasing seismic activity from solar maximum to solar minimum may be in the same range as increasing CR flux; and ii) in those regions of the globe, where the crust is shipped by the magnetic field lines with number L= ~ 2.0, which are populated by anomalous cosmic rays (ACR), the relationship of seismic activity with variations in solar activity will be manifested most clearly, since there is a pronounced dependence of ACR on solar activity variations. Checking an assumption (i) with data of the global seismological catalog of the NEIC, USGS for 1973-2010, it was found that yearly number of earthquake with magnitude M≥4.5 varies into the 11 year solar cycle in a quantitative range of about 7-8% increasing to solar minimum, that qualitatively and quantitatively as well is in agreement with the

  2. Towards solar activity maximum 24 as seen by GOLF and VIRGO/SPM instruments

    NASA Astrophysics Data System (ADS)

    García, R. A.; Salabert, D.; Mathur, S.; Régulo, C.; Ballot, J.; Davies, G. R.; Jiménez, A.; Simoniello, R.

    2013-06-01

    All p-mode parameters vary with time as a response to the changes induced by the cyclic behavior of solar magnetic activity. After the unusual long solar-activity minimum between cycles 23 and 24 -where the p-mode parameters have shown a different behavior than the surface magnetic proxies- we analyze the temporal variation of low-degree p-mode parameters measured by GOLF (in velocity) and VIRGO (in intensity) Sun-as-a-star instruments on board SoHO. We compare our results with other activity proxies.

  3. A Comment on the Suspected Solar Neutrino-Solar Activity Connection

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    1994-01-01

    Recently, it has been proposed that there exists a highly statistically significant (at greater than or equal to 98% level of confidence) relationship between Ar-37 production rate (viz., solar neutrinos) and the Ap geomagnetic index (viz., solar particles), based on the (chi)-square goodness-of-fit test and correlation analysis, for the interval 1970-1990. While a relationship between the two parameters, indeed, seems to be discernible, the strength of the relationship has been overstated. Instead of being significant at the afore-mentioned level of confidence, the relationship is found to be significant at only greater than or equal to 95% level of confidence, based on Yates' modification to the (chi)-square test for 2 x 2 contingency tables. Likewise, while correlation analysis yields a value of r = 0.2691, it is important to note that such a value suggests that only about 7% of the variance can be 'explained' by the inferred correlation and that the remaining 93% of the variance must be attributed to other sources.

  4. Activity associated with coronal mass ejections at solar minimum - SMM observations from 1984-1986

    NASA Technical Reports Server (NTRS)

    St. Cyr, O. C.; Webb, D. F.

    1991-01-01

    Seventy-three coronal mass ejections (CMEs) observed by the coronagraph aboard SMM between 1984 and 1986 were examined in order to determine the distribution of various forms of solar activity that were spatially and temporally associated with mass ejections during solar minimum phase. For each coronal mass ejection a speed was measured, and the departure time of the transient from the lower corona estimated. Other forms of solar activity that appeared within 45 deg longitude and 30 deg latitude of the mass ejection and within +/-90 min of its extrapolated departure time were explored. The statistical results of the analysis of these 73 CMEs are presented, and it is found that slightly less than half of them were infrequently associated with other forms of solar activity. It is suggested that the distribution of the various forms of activity related to CMEs does not change at different phases of the solar cycle. For those CMEs with associations, it is found that eruptive prominences and soft X-rays were the most likely forms of activity to accompany the appearance of mass ejections.

  5. Application of Semi Active Control Techniques to the Damping Suppression Problem of Solar Sail Booms

    NASA Technical Reports Server (NTRS)

    Adetona, O.; Keel, L. H.; Whorton, M. S.

    2007-01-01

    Solar sails provide a propellant free form for space propulsion. These are large flat surfaces that generate thrust when they are impacted by light. When attached to a space vehicle, the thrust generated can propel the space vehicle to great distances at significant speeds. For optimal performance the sail must be kept from excessive vibration. Active control techniques can provide the best performance. However, they require an external power-source that may create significant parasitic mass to the solar sail. However, solar sails require low mass for optimal performance. Secondly, active control techniques typically require a good system model to ensure stability and performance. However, the accuracy of solar sail models validated on earth for a space environment is questionable. An alternative approach is passive vibration techniques. These do not require an external power supply, and do not destabilize the system. A third alternative is referred to as semi-active control. This approach tries to get the best of both active and passive control, while avoiding their pitfalls. In semi-active control, an active control law is designed for the system, and passive control techniques are used to implement it. As a result, no external power supply is needed so the system is not destabilize-able. Though it typically underperforms active control techniques, it has been shown to out-perform passive control approaches and can be unobtrusively installed on a solar sail boom. Motivated by this, the objective of this research is to study the suitability of a Piezoelectric (PZT) patch actuator/sensor based semi-active control system for the vibration suppression problem of solar sail booms. Accordingly, we develop a suitable mathematical and computer model for such studies and demonstrate the capabilities of the proposed approach with computer simulations.

  6. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    DOE PAGES

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

  7. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    SciTech Connect

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; Gracia, Jose R.; King, Thomas Jr.; Liu, Yilu

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructed solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.

  8. Energy spectrum of interplanetary magnetic flux ropes and its connection with solar activity

    NASA Astrophysics Data System (ADS)

    Wu, D. J.; Feng, H. Q.; Chao, J. K.

    2008-03-01

    Context: Recent observations of the solar wind show that interplanetary magnetic flux ropes (IMFRs) have a continuous scale-distribution from small-scale flux ropes to large-scale magnetic clouds. Aims: In this work, we investigate the energy spectrum of IMFRs and its possible connection with solar activity. Methods: In consideration of the detectable probability of an IMFR to be proportional to its diameter, the actual energy spectrum of IMFRs can be obtained from the observed spectrum based on spacecraft observations in the solar wind. Results: It is found that IMFRs have a negative power-law spectrum with an index α = 1.36±0.03, which is similar to that of solar flares, and is probably representative of interplanetary energy spectrum of coronal mass ejections (CMEs), that is, the energy spectrum of interplanetary CMEs (ICMEs). This indicates that the energy distribution of CMEs has a similar negative power-law spectrum. In particular, there are numerous small-scale CMEs in the solar corona, and their interplanetary consequences may be directly detected in situ by spacecraft in the solar wind as small-scale IMFRs, although they are too weak to appear clearly in current coronagraph observations. Conclusions: The presence of small-scale CMEs, especially the energy spectrum of CMEs is potentially important for understanding both the solar magneto-atmosphere and CMEs.

  9. Cycle Length Dependence of Stellar Magnetic Activity and Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Choi, Hwajin; Lee, Jeongwoo; Oh, Suyeon; Kim, Bogyeong; Kim, Hoonkyu; Yi, Yu

    2015-03-01

    Solar cycle (SC) 23 was extraordinarily long with remarkably low magnetic activity. We have investigated whether this is a common behavior of solar-type stars. From the Ca ii H and K line intensities of 111 stars observed at Mount Wilson Observatory from 1966 to 1991, we have retrieved data of all 23 G-type stars and recalculated their cycle lengths using the damped least-squares method for the chromospheric activity index S as a function of time. A regression analysis was performed to find relations between the derived cycle length, Pavg, and the index for excess chromospheric emission, RHK\\prime . As a noteworthy result, we found a segregation between young and old solar-type stars in the cycle length-activity correlation. We incorporated the relation for the solar-type stars into the previously known rule for stellar chromospheric activity and brightness to estimate the variation of solar brightness from SC 22 to SC 23 as (0.12 ± 0.06)%, much higher than the actual variation of total solar irradiance (TSI) ≤0.02%. We have then examined solar spectral irradiance (SSI) to find a good phase correlation with a sunspot number in the wavelength range of 170-260 nm, which is close to the spectral range effective in heating the Earth’s atmosphere. Therefore, it appears that SSI rather than TSI is a good indicator of the chromospheric activity, and its cycle length dependent variation would be more relevant to the possible role of the Sun in the cyclic variation of the Earth’s atmosphere.

  10. Heat Pipe Solar Receiver Development Activities at Sandia National Laboratories

    SciTech Connect

    Adkins, D.R.; Andraka, C.E.; Moreno, J.B.; Moss, T.A.; Rawlinson, K.S.; Showalter, S.K.

    1999-01-08

    Over the past decade, Sandia National Laboratories has been involved in the development of receivers to transfer energy from the focus of a parabolic dish concentrator to the heater tubes of a Stirling engine. Through the isothermal evaporation and condensation of sodium. a heat-pipe receiver can efficiently transfer energy to an engine's working fluid and compensate for irregularities in the flux distribution that is delivered by the concentrator. The operation of the heat pipe is completely passive because the liquid sodium is distributed over the solar-heated surface by capillary pumping provided by a wick structure. Tests have shown that using a heat pipe can boost the system performance by twenty percent when compared to directly illuminating the engine heater tubes. Designing heat pipe solar receivers has presented several challenges. The relatively large area ({approximately}0.2 m{sup 2}) of the receiver surface makes it difficult to design a wick that can continuously provide liquid sodium to all regions of the heated surface. Selecting a wick structure with smaller pores will improve capillary pumping capabilities of the wick, but the small pores will restrict the flow of liquid and generate high pressure drops. Selecting a wick that is comprised of very tine filaments can increase the permeability of the wick and thereby reduce flow losses, however, the fine wick structure is more susceptible to corrosion and mechanical damage. This paper provides a comprehensive review of the issues encountered in the design of heat pipe solar receivers and solutions to problems that have arisen. Topics include: flow characterization in the receiver, the design of wick systems. the minimization of corrosion and dissolution of metals in sodium systems. and the prevention of mechanical failure in high porosity wick structures.

  11. Analysis of magnesium XI line profiles from solar active regions

    NASA Technical Reports Server (NTRS)

    Blake, R. L.; Cowan, R. D.; Felthauser, H.; Fenimore, E. E.; Hockaday, M. P.; Bely-Dubau, F.; Faucher, P.; Steenman-Clark, L.

    1984-01-01

    High-resolution solar spectra of the Mg XI 1s2 1S0-1s2p 1P1 resonance line at 9.169 A and the associated nearby satellite lines obtained from two rocket-borne crystal spectrometer measurements are presented. Comparisons with two independent sets of theoretical calculations for the 1s2nl-1s2pnl dielectronic satellite lines with n = 3-7 indicate electron temperatures of 4-4.5 million K. Measured line widths indicate either that the ion temperature exceeds the electron temperature by about a million K or that about 28 km/s of turbulence is present.

  12. Deep Solar Activity Minimum 2007-2009: Solar Wind Properties and Major Effects on the Terrestrial Magnetosphere

    NASA Technical Reports Server (NTRS)

    Farrugia, C. J.; Harris, B.; Leitner, M.; Moestl, C.; Galvin, A. B.; Simunac, K. D. C.; Torbert, R. B.; Temmer, M. B.; Veronig, A. M.; Erkaev, N. V.; Szabo, A.; Ogilvie, K. W.; Luhman, J. G.; Osherovich, V. A.

    2012-01-01

    We discuss the temporal variations and frequency distributions of solar wind and interplanetary magnetic field parameters during the solar minimum of 2007 - 2009 from measurements returned by the IMPACT and PLASTIC instruments on STEREO-A.We find that the density and total field strength were significantly weaker than in the previous minimum. The Alfven Mach number was higher than typical. This reflects the weakness of magnetohydrodynamic (MHD) forces, and has a direct effect on the solar wind-magnetosphere interactions.We then discuss two major aspects that this weak solar activity had on the magnetosphere, using data from Wind and ground-based observations: i) the dayside contribution to the cross-polar cap potential (CPCP), and ii) the shapes of the magnetopause and bow shock. For i) we find a low interplanetary electric field of 1.3+/-0.9 mV/m and a CPCP of 37.3+/-20.2 kV. The auroral activity is closely correlated to the prevalent stream-stream interactions. We suggest that the Alfven wave trains in the fast streams and Kelvin-Helmholtz instability were the predominant agents mediating the transfer of solar wind momentum and energy to the magnetosphere during this three-year period. For ii) we determine 328 magnetopause and 271 bow shock crossings made by Geotail, Cluster 1, and the THEMIS B and C spacecraft during a three-month interval when the daily averages of the magnetic and kinetic energy densities attained their lowest value during the three years under survey.We use the same numerical approach as in Fairfield's empirical model and compare our findings with three magnetopause models. The stand-off distance of the subsolar magnetopause and bow shock were 11.8 R(sub E) and 14.35 R(sub E), respectively. When comparing with Fairfield's classic result, we find that the subsolar magnetosheath is thinner by approx. 1 R(sub E). This is mainly due to the low dynamic pressure which results in a sunward shift of the magnetopause. The magnetopause is more flared

  13. Deep Solar Activity Minimum 2007-2009: Solar Wind Properties and Major Effects on the Terrestrial Magnetosphere

    NASA Astrophysics Data System (ADS)

    Farrugia, C. J.; Harris, B. S.; Leitner, M.; Moestl, C.; Galvin, A. B.; Simunac, K.; Torbert, R. B.; Temmer, M.; Veronig, A.; Erkaev, N.; Szabo, A.; Ogilvie, K. W.; Luhmann, J. G.; Osherovich, V.

    2012-12-01

    We discuss the temporal variations and frequency distributions of solar wind and IMF parameters during the solar minimum of 2007-2009 from measurements returned by the IMPACT and PLASTIC instruments on STEREO-A. We find that the density and total field strength were significantly weaker than in the previous minimum. The Alfvén Mach number was higher than typical.This reflects the weakness of magnetohydrodynamic (MHD) forces, and has a direct effect on the solar wind-magnetosphere interactions. We then discuss two major aspects that this weak solar activity had on the magnetosphere, using data from textit{Wind} and ground-based observations: (a) the dayside contribution to the cross-polar cap potential (CPCP), and (b) the shapes of the magnetopause and bow shock. For (a) we find a low interplanetary electric field of 1.3 ± 0.9 mV m-1 and a CPCP of 37.3 ± 20.2 kV. The auroral activity is closely correlated to the prevalent stream-stream interactions. We suggest that the Alfvén wave trains in the fast streams and Kelvin-Helmholtz instability were the predominant agents mediating the transfer of solar wind momentum and energy to the magnetosphere during this three-year period. For (b) we determine 328 magnetopause and 271 bow shock crossings made by textit{Geotail, Cluster 1}, and the THEMIS B and C spacecraft during a three-month interval when the daily averages of the magnetic and kinetic energy densities attained their lowest value during the three years under survey. We use the same numerical approach as in Fairfield's (textit{J. Geophys. Res.} 76, 7600, 1971) empirical model and compare our findings with three magnetopause models. The stand-off distance of the subsolar magnetopause and bow shock were 11.8 RE and 14.35 RE, respectively. When comparing with Fairfield's (1971) classic result, we find that the subsolar magnetosheath is thinner by ˜1 RE. This is mainly due to the low dynamic pressure which results in a sunward shift of the magnetopause The

  14. SOLAR MAGNETIC ACTIVITY CYCLES, CORONAL POTENTIAL FIELD MODELS AND ERUPTION RATES

    SciTech Connect

    Petrie, G. J. D.

    2013-05-10

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun vector spectro-magnetograph, the spectro-magnetograph and the 512-channel magnetograph instruments, and from Stanford University's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003 and 2006 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The tilt of the solar dipole is therefore almost entirely due to active-region fields. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking, Solar Eruptive Event Detection System, and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003 and 2012 than for those between 1997 and 2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  15. Solar Activity, Ultraviolet Radiation and Consequences in Birds in Mexico City, 2001- 2002

    NASA Astrophysics Data System (ADS)

    Valdes, M.; Velasco, V.

    2008-12-01

    Anomalous behavior in commercial and pet birds in Mexico City was reported during 2002 by veterinarians at the Universidad Nacional Autonoma de Mexico. This was attributed to variations in the surrounding luminosity. The solar components, direct, diffuse, global, ultraviolet band A and B, as well as some meteorological parameters, temperature, relative humidity, and precipitation, were then analyzed at the Solar Radiation Laboratory. Although the total annual radiance of the previously mentioned radiation components did not show important changes, ultraviolet Band-B solar radiation did vary significantly. During 2001 the total annual irradiance , 61.05 Hjcm² to 58.32 Hjcm², was 1.6 standard deviations lower than one year later, in 2002 and increased above the mean total annual irradiance, to 65.75 Hjcm², 2.04 standard deviations, giving a total of 3.73 standard deviations for 2001-2002. Since these differences did not show up clearly in the other solar radiation components, daily extra-atmosphere irradiance was analyzed and used to calculate the total annual extra-atmosphere irradiance, which showed a descent for 2001. Our conclusions imply that Ultraviolet Band-B solar radiation is representative of solar activity and has an important impact on commercial activity related with birds.

  16. Dependence of the Sunspot-Group Size on the Level of Solar Activity and its Influence on the Calibration of Solar Observers

    NASA Astrophysics Data System (ADS)

    Usoskin, I. G.; Kovaltsov, G. A.; Chatzistergos, T.

    2016-12-01

    We study the distribution of the sunspot-group size (area) and its dependence on the level of solar activity. We show that the fraction of small groups is not constant but decreases with the level of solar activity so that high solar activity is mainly defined by large groups. We analyze the possible influence of solar activity on the ability of a realistic observer to see and report the daily number of sunspot groups. It is shown that the relation between the number of sunspot groups as seen by different observers with different observational acuity thresholds is strongly nonlinear and cannot be approximated by the traditionally used linear scaling (k-factors). The observational acuity threshold [A_{th}] is considered to quantify the quality of each observer, instead of the traditional relative k-factor. A nonlinear c-factor based on A_{th} is proposed, which can be used to correct each observer to the reference conditions. The method is tested on a pair of principal solar observers, Wolf and Wolfer, and it is shown that the traditional linear correction, with the constant k-factor of 1.66 to scale Wolf to Wolfer, leads to an overestimate of solar activity around solar maxima.

  17. The SMM (Solar Maximum Mission) satellite - A dedicated solar activity observatory

    NASA Astrophysics Data System (ADS)

    Vial, J.-C.

    1984-05-01

    The instrumentation on-board the SMM is described, together with data gathered up to November 1980. The SMM carries a gamma ray spectrometer, two hard X ray spectrometers, an X ray polychromator, an UV spectrometer polarimeter, a coronograph/polarimeter and a radiometer. The observational data linked the eruption processes with the appearance of parasitic magnetism, the disappearance of a filament, plasma temperature enhancement to 50,000 K, an increase in the 6 cm flux continuum and hard X ray emission. Measurements have confirmed a two-stage flux acceleration, with highest temperatures happening before peak emissions. The deeper understanding of solar flux phenomena gained with the SMM has been due in large part to an internationally cooperative effort to confirm space-based observations with ground-based measurements.

  18. Nature of the fossil evidence - Moon and meteorites. [solar activity effects

    NASA Technical Reports Server (NTRS)

    Walker, R. M.

    1980-01-01

    The nature of the fossil evidence to be found in extraterrestrial materials concerning the history of solar activity is reviewed. The various types of lunar rocks and meteorites containing evidence of exposure to solar radiations are distinguished, including igneous rocks, breccias, glassy agglutinates, single mineral crystals, carbonaceous meteorites, and the Antarctic meteorites, some of which fell to earth as much as a million years ago. The characteristic effects of energetic particles from space in materials are then examined, including ion implantation and surface radiation damage to a depth of several hundred A by the solar wind, radioactivity, electron trapping and track production induced by solar flares to depths from millimeters to centimeters, and spallation due to galactic cosmic rays at depths from centimeters to meters. Complications in the interpretation of radiation exposure histories represented by dynamic surface processes, the nonsolar origin of some trapped elements, and difficulties in determining the duration and epoch of surface exposure of individual crystals are also noted.

  19. Variation of solar activity recorded in Korean chronicles during the last millennium

    NASA Astrophysics Data System (ADS)

    Yang, Hong-Jin; Jeon, Junhyeok

    2015-08-01

    Korea has a long history in astronomy, which is proved by many observational records written in Korean chronicles. There are 43 sunspot records in Goryeo dynasty (918-1392) and 13 records in Joseon dynasty (1392-1910). According to analysis of Korean historical records, it is known that sunspot records in Goryeo dynasty show well in match with the well-known solar activity of 11.3 years. It means that Korean historical sunspot records show real solar phenomena. Korean sunspot records also show that solar activity decrease in Joseon dynasty compared with the previous ~500 years. In order to know the change of solar activity in detail, we examine Korean historical atmospheric records which can indicate climate change. We first analyze historical frost records. Korean chronicles have around 600 frost records during the last millennium. We find that the climate change shows sign of cooling down when check the variation of epoch that the first and last frost events in each year are written. This result is well in accord with that of historical sunspot records. Therefore, we claim that solar activity decrease during the last thousand years.

  20. 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.

  1. Models of the quiet and active solar atmosphere from Harvard OSO data.

    NASA Technical Reports Server (NTRS)

    Noyes, R. W.

    1971-01-01

    Review of some Harvard Observatory programs aimed at defining the physical conditions in quiet and active solar regions on the basis of data obtained from the OSO-IV and OSO-VI spacecraft. The spectral range covered is from 300 A to 1400 A. This spectral range consists of emission lines and continua from abundant elements such as hydrogen, helium, carbon, nitrogen, oxygen, silicon, magnesium, aluminum, neon, iron, and calcium in various ionization states ranging from neutral to 15 times ionized. The structure is discussed of the quiet solar atmosphere as deduced from center-to-limb behavior of spectral lines and continua formed in the chromosphere and corona. In reviewing investigations of solar active regions, it is shown that the structure of these regions varies in a complicated manner from point to point. The local structure is influenced by factors such as the magnetic field configuration within the active region and the age or evolutionary state of the region.

  2. A THEORY ON THE CONVECTIVE ORIGINS OF ACTIVE LONGITUDES ON SOLAR-LIKE STARS

    SciTech Connect

    Weber, Maria A.; Fan Yuhong; Miesch, Mark S.

    2013-06-20

    Using a thin flux tube model in a rotating spherical shell of turbulent, solar-like convective flows, we find that the distribution of emerging flux tubes in our simulation is inhomogeneous in longitude, with properties similar to those of active longitudes on the Sun and other solar-like stars. The large-scale pattern of flux emergence our simulations produce exhibits preferred longitudinal modes of low order, drift with respect to a fixed reference system, and alignment across the equator at low latitudes between {+-}15 Degree-Sign . We suggest that these active-longitude-like emergence patterns are the result of columnar, rotationally aligned giant cells present in our convection simulation at low latitudes. If giant convecting cells exist in the bulk of the solar convection zone, this phenomenon, along with differential rotation, could in part provide an explanation for the behavior of active longitudes.

  3. Solar Activity and Climate - in Light of the Decay of the Dipole

    NASA Astrophysics Data System (ADS)

    Friis-Christensen, E.

    2003-12-01

    The geological history shows that climate has always been changing. The climate is the result of very complex interactions between various atmospheric processes, which are not well understood. Variations in solar activity seem to have a significant - but not simple - effect on climate. Recently it has been suggested that solar activity modulation of cosmic rays influences the formation and properties of clouds and thereby the radiation balance of the Earth. This topic was selected as one of six 'Areas to Watch in 2003' in the 20th December 2002 edition of Science. Since the Earth's magnetic field also has a modulating effect on the cosmic ray flux into the atmosphere, one might expect an effect on climate as well. A review of solar activity variations and climate changes will be given with emphasis on those aspects that may be affected by the varying geomagnetic field.

  4. 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.

  5. 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.

  6. Influence of solar activity on the precipitation in the North-central China

    NASA Astrophysics Data System (ADS)

    Zhai, Qian

    2017-02-01

    The time series of sunspot number and the precipitation in the north-central China (108° ∼ 115° E, 33° ∼ 41° N) over the past 500 years (1470-2002) are investigated, through periodicity analysis, cross wavelet transform and ensemble empirical mode decomposition analysis. The results are as follows: the solar activity periods are determined in the precipitation time series of weak statistical significance, but are found in decomposed components of the series with statistically significance; the Quasi Biennial Oscillation (QBO) is determined to significantly exist in the time series, and its action on precipitation is opposite to the solar activity; the sun is inferred to act on precipitation in two ways, with one lagging the other by half of the solar activity period.

  7. Chromosome aberration and environmental physical activity: Down syndrome and solar and cosmic ray activity, Israel, 1990-2000

    NASA Astrophysics Data System (ADS)

    Stoupel, Eliahu G.; Frimer, Helena; Appelman, Zvi; Ben-Neriah, Ziva; Dar, Hanna; Fejgin, Moshe D.; Gershoni-Baruch, Ruth; Manor, Esther; Barkai, Gad; Shalev, Stavit; Gelman-Kohan, Zully; Reish, Orit; Lev, Dorit; Davidov, Bella; Goldman, Boleslaw; Shohat, Mordechai

    2005-09-01

    The possibility that environmental effects are associated with chromosome aberrations and various congenital pathologies has been discussed previously. Recent advances in the collection and computerization of data make studying these potential associations more feasible. The aim of this study was to investigate a possible link between the number of Down syndrome (DS) cases detected prenatally or at birth yearly in Israel over a 10-year period compared with the levels of solar and cosmic ray activity 1 year before the detection or birth of each affected child. Information about 1,108,449 births was collected for the years 1990-2000, excluding 1991, when data were unavailable. A total of 1,310 cases of DS were detected prenatally or at birth—138 in the non-Jewish community and 1,172 in the Jewish population. Solar activity indices—sunspot number and solar radio flux 2,800 MHz at 10.7 cm wavelength for 1989-1999—were compared with the number of DS cases detected. Pearson correlation coefficients (r) and their probabilities (P) were established for the percentage of DS cases in the whole population. There was a significant inverse correlation between the indices of solar activity and the number of cases of DS detected—r=-0.78, P=0.008 for sunspot number and r=-0.76, P=0.01 for solar flux. The possibility that cosmophysical factors inversely related to solar activity play a role in the pathogenesis of chromosome aberrations should be considered. We have confirmed a strong trend towards an association between the cosmic ray activity level and the incidence of DS.

  8. Chromosome aberration and environmental physical activity: Down syndrome and solar and cosmic ray activity, Israel, 1990-2000.

    PubMed

    Stoupel, Eliahu G; Frimer, Helena; Appelman, Zvi; Ben-Neriah, Ziva; Dar, Hanna; Fejgin, Moshe D; Gershoni-Baruch, Ruth; Manor, Esther; Barkai, Gad; Shalev, Stavit; Gelman-Kohan, Zully; Reish, Orit; Lev, Dorit; Davidov, Bella; Goldman, Boleslaw; Shohat, Mordechai

    2005-09-01

    The possibility that environmental effects are associated with chromosome aberrations and various congenital pathologies has been discussed previously. Recent advances in the collection and computerization of data make studying these potential associations more feasible. The aim of this study was to investigate a possible link between the number of Down syndrome (DS) cases detected prenatally or at birth yearly in Israel over a 10-year period compared with the levels of solar and cosmic ray activity 1 year before the detection or birth of each affected child. Information about 1,108,449 births was collected for the years 1990-2000, excluding 1991, when data were unavailable. A total of 1,310 cases of DS were detected prenatally or at birth--138 in the non-Jewish community and 1,172 in the Jewish population. Solar activity indices--sunspot number and solar radio flux 2,800 MHz at 10.7 cm wavelength for 1989-1999--were compared with the number of DS cases detected. Pearson correlation coefficients (r) and their probabilities (P) were established for the percentage of DS cases in the whole population. There was a significant inverse correlation between the indices of solar activity and the number of cases of DS detected--r=-0.78, P=0.008 for sunspot number and r=-0.76, P=0.01 for solar flux. The possibility that cosmophysical factors inversely related to solar activity play a role in the pathogenesis of chromosome aberrations should be considered. We have confirmed a strong trend towards an association between the cosmic ray activity level and the incidence of DS.

  9. The Solar Wind and Geomagnetic Activity as a Function of Time Relative to Corotating Interaction Regions

    NASA Technical Reports Server (NTRS)

    McPherron, Robert L.; Weygand, James

    2006-01-01

    Corotating interaction regions during the declining phase of the solar cycle are the cause of recurrent geomagnetic storms and are responsible for the generation of high fluxes of relativistic electrons. These regions are produced by the collision of a high-speed stream of solar wind with a slow-speed stream. The interface between the two streams is easily identified with plasma and field data from a solar wind monitor upstream of the Earth. The properties of the solar wind and interplanetary magnetic field are systematic functions of time relative to the stream interface. Consequently the coupling of the solar wind to the Earth's magnetosphere produces a predictable sequence of events. Because the streams persist for many solar rotations it should be possible to use terrestrial observations of past magnetic activity to predict future activity. Also the high-speed streams are produced by large unipolar magnetic regions on the Sun so that empirical models can be used to predict the velocity profile of a stream expected at the Earth. In either case knowledge of the statistical properties of the solar wind and geomagnetic activity as a function of time relative to a stream interface provides the basis for medium term forecasting of geomagnetic activity. In this report we use lists of stream interfaces identified in solar wind data during the years 1995 and 2004 to develop probability distribution functions for a variety of different variables as a function of time relative to the interface. The results are presented as temporal profiles of the quartiles of the cumulative probability distributions of these variables. We demonstrate that the storms produced by these interaction regions are generally very weak. Despite this the fluxes of relativistic electrons produced during those storms are the highest seen in the solar cycle. We attribute this to the specific sequence of events produced by the organization of the solar wind relative to the stream interfaces. We also

  10. Method and apparatus for measuring solar activity and atmospheric radiation effects

    NASA Technical Reports Server (NTRS)

    Haroules, G. G.; Brown, W. E., III (Inventor)

    1973-01-01

    A radiometric measuring system is described for observing solar activity, atmospheric attenuation, and atmospheric emission. Two highly directional microwave antennas are mounted side by-side on an equatorial mount which tracks the sun. One antenna is aimed directly at the sun to provide a sun temperature, and the other antenna is aimed at a slight angle to the sun antenna to provide a sky temperature reference. Signals from the two antennas are compared in a radiometric detecting system and provide information concerning solar activity and atmospheric attenuation and emission.

  11. Radio Observation of Solar-Activity-Related mHz Oscillations

    NASA Astrophysics Data System (ADS)

    Hiep, N. V.; Nhung, P. T.; Darriulat, P.; Diep, P. N.; Anh, P. T.; Dong, P. N.; Hoai, D. T.; Thao, N. T.

    2014-03-01

    The VATLY radio telescope, operating at 1.415 GHz in Ha Noi, has been used to track the Sun in the summer - autumn months in 2012. Evidence has been obtained for solar activity, including occasional flares and variable oscillations with amplitudes at the percent level and periods of about 6 min. Comparison with data collected at the same frequency by the Learmonth Observatory in Australia suggests that the observed oscillations were associated with solar activity. A joint analysis of both data sets is presented, evaluating the correlations between them. We describe the common and different main features.

  12. The technical analysis of the stock exchange and physics: Japanese candlesticks for solar activity

    NASA Astrophysics Data System (ADS)

    Dineva, C.; Atanasov, V.

    2013-09-01

    In this article, we use the Japanese candlesticks, a method popular in the technical analysis of the Stock/Forex markets and apply it to a variable in physics-the solar activity. This method is invented and used exclusively for economic analysis and its application to a physical problem produced unexpected results. We found that the Japanese candlesticks are convenient tool in the analysis of the variables in the physics of the Sun. Based on our observations, we differentiated a new cycle in the solar activity.

  13. Planetary waves and solar activity in the stratosphere between 50 and 10 mbar

    NASA Astrophysics Data System (ADS)

    Ebel, A.; Schwister, B.; Labitzke, K.

    1981-10-01

    The effects of solar activity on the geopotential height and temperature fields on the 50-, 30-, and 10-mbar surface, resolved into zonal harmonic components, are investigated. The investigation is carried out through a cross-spectral analysis between the 10.7-cm radiation of the sun and planetary waves up to zonal wave number 3. Frequent significant responses of various harmonic components in a broad range of oscillation frequencies provide evidence that solar activity plays a significant role for the dynamics of the middle and lower stratosphere.

  14. Coronal Dynamic Activities in the Declining Phase of a Solar Cycle

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  15. Latitude dependence of the solar granulation during the minimum of activity in 2009

    NASA Astrophysics Data System (ADS)

    Muller, R.; Hanslmeier, A.; Utz, D.

    2017-01-01

    Context. Knowledge of the latitude variation of the solar granulation properties (contrast and scale) is useful to better understand interactions between magnetic field, convection, differential rotation, and meridional circulation in the solar atmosphere. Aims: We investigated the latitude dependence of the contrast and scale of the solar granulation, with the help of HINODE/SOT blue continuum images taken in the frame of the HOP 79 program, along the central meridian and along the equator on a monthly basis in 2009 during the last solar minimum of activity. Methods: We selected the sharpest images in latitude and longitude intervals. The selected images in all the N-S and E-W scans taken in 2009 were combined to get statistically reliable results. Results: The contrast of the solar granulation decreases towards the poles and the scale increases, but not regularly since a perturbation occurs at around 60° where both quantities return close to their values at the disk center. Conclusions: Such a latitude variation in a period of minimum of activity (2009), is probably not due to magnetic field, neither the quiet magnetic field at the surface, nor the strong magnetic flux tubes associated with active regions, which could be embedded more or less deeply in the convection zone before they reach the surface. The decrease in contrast and increase in scale towards the pole seem to be related to the differential rotation and the perturbation around 60° to the meridional circulation.

  16. 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

    2015-11-07

    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.

  17. The solar magnetic activity band interaction and instabilities that shape quasi-periodic variability

    PubMed Central

    McIntosh, Scott W.; Leamon, Robert J.; Krista, Larisza D.; Title, Alan M.; Hudson, Hugh S.; Riley, Pete; Harder, Jerald W.; Kopp, Greg; Snow, Martin; Woods, Thomas N.; Kasper, Justin C.; Stevens, Michael L.; Ulrich, Roger K.

    2015-01-01

    Solar magnetism displays a host of variational timescales of which the enigmatic 11-year sunspot cycle is most prominent. Recent work has demonstrated that the sunspot cycle can be explained in terms of the intra- and extra-hemispheric interaction between the overlapping activity bands of the 22-year magnetic polarity cycle. Those activity bands appear to be driven by the rotation of the Sun's deep interior. Here we deduce that activity band interaction can qualitatively explain the ‘Gnevyshev Gap'—a well-established feature of flare and sunspot occurrence. Strong quasi-annual variability in the number of flares, coronal mass ejections, the radiative and particulate environment of the heliosphere is also observed. We infer that this secondary variability is driven by surges of magnetism from the activity bands. Understanding the formation, interaction and instability of these activity bands will considerably improve forecast capability in space weather and solar activity over a range of timescales. PMID:25849045

  18. The solar magnetic activity band interaction and instabilities that shape quasi-periodic variability.

    PubMed

    McIntosh, Scott W; Leamon, Robert J; Krista, Larisza D; Title, Alan M; Hudson, Hugh S; Riley, Pete; Harder, Jerald W; Kopp, Greg; Snow, Martin; Woods, Thomas N; Kasper, Justin C; Stevens, Michael L; Ulrich, Roger K

    2015-04-07

    Solar magnetism displays a host of variational timescales of which the enigmatic 11-year sunspot cycle is most prominent. Recent work has demonstrated that the sunspot cycle can be explained in terms of the intra- and extra-hemispheric interaction between the overlapping activity bands of the 22-year magnetic polarity cycle. Those activity bands appear to be driven by the rotation of the Sun's deep interior. Here we deduce that activity band interaction can qualitatively explain the 'Gnevyshev Gap'—a well-established feature of flare and sunspot occurrence. Strong quasi-annual variability in the number of flares, coronal mass ejections, the radiative and particulate environment of the heliosphere is also observed. We infer that this secondary variability is driven by surges of magnetism from the activity bands. Understanding the formation, interaction and instability of these activity bands will considerably improve forecast capability in space weather and solar activity over a range of timescales.

  19. Periodic Analysis of Solar Activity and its Link with the Arctic Oscillation Phenomenon

    NASA Astrophysics Data System (ADS)

    Qu, Weizheng; Li, Yanfang; Li, Chun; Du, Ling; Huang, Fei

    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

  20. Contributions of Active Regions, Sunspots, Quiet Sun to the Solar UV Spectrum

    NASA Astrophysics Data System (ADS)

    Morrill, J. S.; McMullin, D. R.; Cookson, A.; Chapman, G. A.

    2011-12-01

    During the declining phase of the most recent solar cycle, the full disk solar UV spectrum was measured by several space-based instruments, including the SOLSTICE and SIM instruments on the SORCE satellite and the SUSIM instrument on the UARS satellite. These results show distinctively different behavior and have implications for our understanding of the contributions played by various surface features in producing the disk integrated UV spectrum as well as the impact of solar UV emissions on climate. The primary goal of this study is to determine the impact of regions of increased activity (e.g. plage and sunspots) during the recent solar cycle and how this relates to variability of the solar spectrum. Two important results from this study will be the plage and sunspot UV contrast compared to the quiet as well as the center to limb variability of plage, sunspots, and the quiet sun at UV wavelengths. This study will estimate the solar spectrum by utilizing the recently digitized UV spectral radiance observations of plage, sunspots, the quiet sun made by the S082B spectrograph on Skylab, Ca II K images collected at San Fernando Observatory during the recent solar cycle, and a solar spectral model developed under a previous NASA grant. Once generated, these spectra will be compared to the UV observations produced by the above instruments. An important step in the estimation process involves the calibration of the Skylab data for a valid comparison between model and observed spectra. This will require separate calibration curves for SUSIM and SORCE observations. These will be generated from days of no or minimal activity. The determination of separate calibrations will allow any subtle contributions due to variations in instrument performance to be accounted for in the comparison of model and observed spectra. Also, changes in instrumental behavior over time will be separable from real changes in the solar spectrum which are due to contributions of active solar

  1. Contributions of Active Regions, Sunspots, Quiet Sun to the Solar UV Spectrum

    NASA Astrophysics Data System (ADS)

    Morrill, J. S.; McMullin, D. R.; Cookson, A.; Chapman, G. A.

    2013-12-01

    During the declining phase of the most recent solar cycle, the full disk solar UV spectrum was measured by several space-based instruments, including the SOLSTICE and SIM instruments on the SORCE satellite and the SUSIM instrument on the UARS satellite. These results show distinctively different behavior and have implications for our understanding of the contributions played by various surface features in producing the disk integrated UV spectrum as well as the impact of solar UV emissions on climate. The primary goal of this study is to determine the impact of regions of increased activity (e.g. plage and sunspots) during the recent solar cycle and how this relates to variability of the solar spectrum. Two important results from this study will be the plage and sunspot UV contrast compared to the quiet as well as the center to limb variability of plage, sunspots, and the quiet sun at UV wavelengths. This study will estimate the solar spectrum by utilizing the recently digitized UV spectral radiance observations of plage, sunspots, the quiet sun made by the S082B spectrograph on Skylab, Ca II K images collected at San Fernando Observatory during the recent solar cycle, and a solar spectral model developed under a previous NASA grant. Once generated, these spectra will be compared to the UV observations produced by the above instruments. An important step in the estimation process involves the calibration of the Skylab data for a valid comparison between model and observed spectra. This will require separate calibration curves for SUSIM and SORCE observations. These will be generated from days of no or minimal activity. The determination of separate calibrations will allow any subtle contributions due to variations in instrument performance to be accounted for in the comparison of model and observed spectra. Also, changes in instrumental behavior over time will be separable from real changes in the solar spectrum which are due to contributions of active solar

  2. 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

  3. A Time-Frequency Analysis of the Effects of Solar Activities on Tropospheric Thermodynamics

    NASA Technical Reports Server (NTRS)

    Kiang, Richard K.; Kyle, H. Lee; Wharton, Stephen W. (Technical Monitor)

    2001-01-01

    Whether the Sun has significantly influenced the climate during the last century has been under extensive debates for almost two decades. Since the solar irradiance varies very little in a solar cycle, it is puzzling that some geophysical parameters show proportionally large variations which appear to be responding to the solar cycles. For example, variation in low altitude clouds is shown correlated with solar cycle, and the onset of Forbush decrease is shown correlated with the reduction of the vorticity area index. A possible sun-climate connection is that galactic cosmic rays modulated by solar activities influence cloud formation. In this paper, we apply wavelet transform to satellite and surface data to examine this hypothesis. Data analyzed include the time series for solar irradiance, sunspots, UV index, temperature, cloud coverage, and neutron counter measurements. The interactions among the elements in the Earth System under the external and internal forcings give out very complex signals.The periodicity of the forcings or signals could range widely. Since wavelet transforms can analyze multi-scale phenomena that are both localized in frequency and time, it is a very useful technique for detecting, understanding and monitoring climate changes.

  4. Diurnal anisotropy of cosmic rays during intensive solar activity for the period 2001-2014

    NASA Astrophysics Data System (ADS)

    Tezari, A.; Mavromichalaki, H.

    2016-07-01

    The diurnal variation of cosmic ray intensity, based on the records of two neutron monitor stations at Athens (Greece) and Oulu (Finland) for the time period 2001 to 2014, is studied. This period covers the maximum and the descending phase of the solar cycle 23, the minimum of the solar cycles 23/24 and the ascending phase of the solar cycle 24.These two stations differ in their geographic latitude and magnetic threshold rigidity. The amplitude and phase of the diurnal anisotropy vectors have been calculated on annual and monthly basis. From our analysis it is resulted that there is a different behaviour in the characteristics of the diurnal anisotropy during the different phases of the solar cycle, depended on the solar magnetic field polarity, but also during extreme events of solar activity, such as Ground Level Enhancements and cosmic ray events, such as Forbush decreases and magnetospheric events. These results may be useful to Space Weather forecasting and especially to Biomagnetic studies.

  5. On the Current Solar Magnetic Activity in the Light of Its Behaviour During the Holocene

    NASA Astrophysics Data System (ADS)

    Inceoglu, F.; Simoniello, R.; Knudsen, M. F.; Karoff, C.; Olsen, J.; Turck-Chièze, S.

    2016-01-01

    Solar modulation potential (SMP) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behaviour of the open solar magnetic field over the Holocene period. We aim at comparing the Sun's large-scale magnetic field behaviour over the last three solar cycles with variations in the SMP reconstruction through the Holocene epoch. To achieve these objectives, we use the IntCal13 14C data to investigate distinct patterns in the occurrences of grand minima and maxima during the Holocene period. We then check whether these patterns might mimic the recent solar magnetic activity by investigating the evolution of the energy in the Sun's large-scale dipolar magnetic field using the Wilcox Solar Observatory data. The cosmogenic radionuclide data analysis shows that {≈} 71 % of grand maxima during the period from 6600 BC to 1650 AD were followed by a grand minimum. The characteristics of the occurrences of grand maxima and minima are consistent with the scenario in which the dynamical non-linearity induced by the Lorentz force leads the Sun to act as a relaxation oscillator. This finding implies that the probability for these events to occur is non-uniformly distributed in time, as there is a memory in their driving mechanism, which can be identified via the back-reaction of the Lorentz force.

  6. Long-term global temperature variations under total solar irradiance, cosmic rays, and volcanic activity.

    PubMed

    Biktash, Lilia

    2017-07-01

    The effects of total solar irradiance (TSI) and volcanic activity on long-term global temperature variations during solar cycles 19-23 were studied. It was shown that a large proportion of climate variations can be explained by the mechanism of action of TSI and cosmic rays (CRs) on the state of the lower atmosphere and other meteorological parameters. The role of volcanic signals in the 11-year variations of the Earth's climate can be expressed as several years of global temperature drop. Conversely, it was shown that the effects of solar, geophysical, and human activity on climate change interact. It was concluded that more detailed investigations of these very complicated relationships are required, in order to be able to understand issues that affect ecosystems on a global scale.

  7. North Atlantic sea surface temperature, solar activity and the climate of Northern Fennoscandia

    NASA Astrophysics Data System (ADS)

    Ogurtsov, M.; Lindholm, M.; Jalkanen, R.; Veretenenko, S. V.

    2017-02-01

    Seven proxies of summer temperature in Northern Fennoscandia, sea surface temperature in the North Atlantic and solar activity were analyzed over AD 1567-1986. A stable and significant positive correlation between summer temperatures in Northern Fennoscandia and sea surface temperature in the North Atlantic is shown to exist during the entire time interval. In addition, a significant correlation between solar activity and (a) summer temperature in Northern Fennoscandia as well as (b) surface temperature in the North Atlantic was found during AD 1715-1986. Throughout 1567-1715 correlation is less significant and has an opposite sign. Thus we show that the variation of sea surface temperature in the North Atlantic could be a physical agent, which transferred solar influence on Northern Fennoscandian temperature at least during AD 1715-1986.

  8. An overview of current activities at the National Solar Thermal Test Facility

    NASA Astrophysics Data System (ADS)

    Cameron, C. P.; Klimas, P. C.

    This paper is a description of the United States Department of Energy's National Solar Thermal Test Facility, highlighting current test programs. In the central receiver area, research underway supports commercialization of molten nitrate salt technology, including receivers, thermal energy transport, and corrosion experiments. Concentrator research includes large-area, glass-metal heliostats and stretched-membrane heliostats and dishes. Test activities in support of dish-Stirling systems with reflux receivers are described. Research on parabolic troughs includes characterization of several receiver configurations. Other test facility activities include solar detoxification experiments, design assistance testing of commercially-available solar hardware, and non-DOE-funded work, including thermal exposure tests and testing of volumetric and PV central receiver concepts.

  9. Occurrence rate of SAR arcs during the 23nd solar activity cycle

    NASA Astrophysics Data System (ADS)

    Ievenko, Igor

    By data of photometric observations at the Maimaga station (57° N, 200° E, geomagnetic coordinates) at the Yakutsk meridian the occurrence rate of subauroral red (SAR) arcs for the 1997 to 2006 period has been analysed. The observations were carried out during winterspring periods at moonless nights under favorable atmospheric conditions. For˜370 nights of observations (total duration is˜3170 hours) 114 cases of SAR arcs occurrence (˜500 hours) have been registered. The occurrence rate of SAR arcs have been determined as a ratio of the number of registration hour intervals of SAR arcs to the summary observation time in hours for particular months. Subauroral red arcs have been registered every year both in the maximum and in the minimum of the solar activity cycle. The most observation occurrence of red arcs is registered on the rise (˜27%) and decay of the maximum of the solar activity cycle (˜36%). The average occurrence rate of SAR arcs during these years was less than in the 22nd solar activity cycle and is equal to ˜16% of the total observation time. The occurrence rate of SAR arcs observations corresponds to the changes of geomagnetic activity during the 23nd solar activity cycle.

  10. Revisiting the prediction of solar activity based on the relationship between the solar maximum amplitude and max-max cycle length

    NASA Astrophysics Data System (ADS)

    Carrasco, V. M. S.; Vaquero, J. M.; Gallego, M. C.

    2017-01-01

    It is very important to forecast the future solar activity due to its effect on our planet and near space. Here, we employ the new version of the sunspot number index (version 2) to analyse the relationship between the solar maximum amplitude and max-max cycle length proposed by Du (2006). We show that the correlation between the parameters used by Du (2006) for the prediction of the sunspot number (amplitude of the cycle, Rm, and max-max cycle length for two solar cycles before, Pmax-2) disappears when we use solar cycles prior to solar cycle 9. We conclude that the correlation between these parameters depends on the time interval selected. Thus, the proposal of Du (2006) should definitively not be considered for prediction purposes.

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

    SciTech Connect

    Raphaldini, Breno; Raupp, Carlos F. M. E-mail: carlos.raupp@iag.usp.br

    2015-01-20

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

  12. 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.

  13. Multi-wavelength and High-resolution Observations of Solar Eruptive Activities

    NASA Astrophysics Data System (ADS)

    Shen, Y. D.

    2014-09-01

    In recent years, various solar eruptive activities have been observed in the solar atmosphere, such as solar flares, filament eruptions, jets, coronal mass ejections (CMEs), and magnetohydrodynamics (MHD) waves. Previous observations have indicated that solar magnetic field plays a dominant role in the processes of all kinds of solar activities. Since many large-scale solar eruptive activities can cause significant effects on the space environment of the Earth as well as the human life, studying and forecasting the solar activities are urgent tasks for us. In addition, the Sun is the nearest star to the Earth, so that people can directly observe and study it in detail. Hence, studying the Sun can also provide a reference to study other stars in the universe. This thesis focuses on the multi-wavelength and high-resolution observations of three types of solar eruptive activities: filament eruptions, coronal jets, and coronal MHD waves. By analyzing various observations taken by ground-based and space-borne instruments, we try to understand the inherent physical mechanisms, and construct models to interpret different kinds of solar eruptive activities. The triggering mechanism and the cause of a failed filament eruption are studied in Chapter 3, which indicates that the energy released in the flare is a key factor to the fate of the filament. Two successive filament eruptions are studied in Chapter 4, which indicates that the magnetic implosion could be the physical linkage between them, and the structures of coronal magnetic fields are important for producing sympathetic eruptions. A magnetic unwinding jet and a blowout jet are studied in Chapters 5 and 6, respectively. The former exhibits obvious radial expansion, which undergoes three distinct phases: the slow expansion phase, the fast expansion phase, and the steady phase. In addition, calculation indicates that the non-potential magnetic field in the jet can supply sufficient energy for producing the unwinding

  14. On the Dependence of the Ionospheric E-Region Electric Field of the Solar Activity

    NASA Astrophysics Data System (ADS)

    Denardini, Clezio Marcos; Schuch, Nelson Jorge; Moro, Juliano; Araujo Resende, Laysa Cristina; Chen, Sony Su; Costa, D. Joaquim

    2016-07-01

    We have being studying the zonal and vertical E region electric field components inferred from the Doppler shifts of type 2 echoes (gradient drift irregularities) detected with the 50 MHz backscatter coherent (RESCO) radar set at Sao Luis, Brazil (SLZ, 2.3° S, 44.2° W) during the solar cycle 24. In this report we present the dependence of the vertical and zonal components of this electric field with the solar activity, based on the solar flux F10.7. For this study we consider the geomagnetically quiet days only (Kp <= 3+). A magnetic field-aligned-integrated conductivity model was developed for proving the conductivities, using the IRI-2007, the MISIS-2000 and the IGRF-11 models as input parameters for ionosphere, neutral atmosphere and Earth magnetic field, respectively. The ion-neutron collision frequencies of all the species are combined through the momentum transfer collision frequency equation. The mean zonal component of the electric field, which normally ranged from 0.19 to 0.35 mV/m between the 8 and 18 h (LT) in the Brazilian sector, show a small dependency with the solar activity. Whereas, the mean vertical component of the electric field, which normally ranges from 4.65 to 10.12 mV/m, highlight the more pronounced dependency of the solar flux.

  15. Possible impact of solar activity on the convection dipole over the tropical pacific ocean

    NASA Astrophysics Data System (ADS)

    Xiao, Ziniu; Liao, Yunchen; Li, Chongyin

    2016-03-01

    The impact of solar activity (F10.7) on tropical Pacific convection during the boreal summer (June-July-August, JJA) has been examined using reanalysis data, revealing a significant lagged (1-2 years) correlation between outgoing long-wave radiation (OLR) over the tropical western Pacific and the F10.7 index. The OLR anomaly over the tropical western Pacific and the maritime continent shows a dipole pattern during the 1-2 years following high solar (HS) years. Furthermore, the first mode of the empirical orthogonal function (EOF) analysis on the OLR with the El Niño/Southern Oscillation (ENSO) signal removed is similar to the distribution of correlation coefficients between the JJA mean F10.7 index and the OLR with ENSO signal removed. The correlation and composite analyzes of the OLR, velocity potential and vertical velocity reveals that this convection dipole pattern shows an eastward shift of the central position of deep convection, as related to the influence of solar activity over the tropical western Pacific. Further analyzes show that the evolutionary process of the solar signal in the ocean-atmosphere system over the tropical western Pacific is consistent with the analyzes of OLR, velocity potential, and vertical velocity. By modulating vertical air temperature, the solar signal in the tropical sea surface temperature (SST) may contribute to the triggering of a lagged convection dipole pattern.

  16. Coronal Radio Sounding Experiments with Mars Express: Scintillation Spectra during Low Solar Activity

    SciTech Connect

    Efimov, A. I.; Lukanina, L. A.; Samoznaev, L. N.; Rudash, V. K.; Chashei, I. V.; Bird, M. K.; Paetzold, M.; Tellmann, S.

    2010-03-25

    Coronal radio sounding observations were carried out with the radio science experiment MaRS on the ESA spacecraft Mars Express during the period from 25 August to 22 October 2004. Differential frequency and log-amplitude fluctuations of the dual-frequency signals were recorded during a period of low solar activity. The data are applicable to low heliographic latitudes, i.e. to slow solar wind. The mean frequency fluctuation and power law index of the frequency fluctuation temporal spectra are determined as a function of heliocentric distance. The radial dependence of the frequency fluctuation spectral index alpha reflects the previously documented flattening of the scintillation power spectra in the solar wind acceleration region. Temporal spectra of S-band and X-band normalized log-amplitude fluctuations were investigated over the range of fluctuation frequencies 0.01 Hzsolar activity. Ranging measurements are presented and compared with frequency and log-amplitude scintillation data. Evidence for a weak increase in the fractional electron density turbulence level is obtained in the range 10-40 solar radii.

  17. Coronal X-ray activity preceding solar flares

    NASA Technical Reports Server (NTRS)

    Webb, D. F.

    1985-01-01

    The characteristics of coronal emplacements preceding solar flares were investigated based on a comprehensive survey of Skylab soft X-ray images. A search interval of 30 min before flare was used in the X-ray observations. X-ray images with preflare enhancements were compared with high resolution H-alpha images and photospheric magnetograms and preflare enhancements were found in a statistically significant number of the observed preflare intervals. The enhancement events consisted of loops, kernels, and sinuous features with one to three separate preflare structures appearing in each interval. Typical gas pressures in the preflare X-ray features were estimated on the order of a few dyne per sq cm and densities were 4-10 x 10 to the -9th per cu cm for assumed average temperatures. H-alpha brightenings in the form of knots and patches were found in conjunction with the X-ray preflare features in nearly all of the intervals. It is concluded that H-alpha emission is characteristic of preflare emission processes. The observational data are interpreted within the framework of existing loop preheating models, and the results are discussed in detail.

  18. Highly efficient graphene-based Cu(In, Ga)Se₂ solar cells with large active area.

    PubMed

    Yin, Ling; Zhang, Kang; Luo, Hailin; Cheng, Guanming; Ma, Xuhang; Xiong, Zhiyu; Xiao, Xudong

    2014-09-21

    Two-dimensional graphene has tremendous potential to be used as a transparent conducting electrode (TCE), owing to its high transparency and conductivity. To date graphene films have been applied to several kinds of solar cells except the Cu(In, Ga)Se₂ (CIGS) solar cell. In this work, we present a novel TCE structure consisting of a doped graphene film and a thin layer of poly(methyl methacrylate) (PMMA) to replace the ZnO:Al (AZO) electrode for CIGS. By optimizing the contact between graphene and intrinsic ZnO (i-ZnO), a high power conversion efficiency (PCE) of 13.5% has been achieved, which is among the highest efficiencies of graphene-based solar cells ever reported and approaching those of AZO-based solar cells. Besides, the active area of our solar cells reaches 45 mm(2), much larger than other highly efficient graphene-based solar cells (>10%) reported so far. Moreover, compared with AZO-based CIGS solar cells, the total reflectance of the graphene-based CIGS solar cells is decreased and the quantum efficiency of the graphene-based CIGS is enhanced in the near infrared region (NIR), which strongly support graphene as a competitive candidate material for the TCE in the CIGS solar cell. Furthermore, the graphene/PMMA film can protect the solar cell from moisture, making the graphene-based solar cells much more stable than the AZO-based solar cells.

  19. Are Solar Activity Variations Amplified by the QBO: A Modeling Study

    NASA Technical Reports Server (NTRS)

    Mengel, J. G.; Mayr, H. G.; Drob, D. P.; Porter, H. S.; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Solar cycle activity effects (SCAE) in the lower and middle atmosphere, reported in several studies, are difficult to explain on the basis of the small changes in solar radiation that accompany the 11-year cycle. It is therefore natural to speculate that dynamical processes may come into play to produce a leverage. Such a leverage may be provided by the Quasi-Biennial Oscillation (QBO) in the zonal circulation of the stratosphere, which has been linked to solar activity variations. Driven primarily by wave mean flow interaction, the QBO period and its amplitude are variable but are also strongly influenced by the seasonal cycle in the solar radiation. This influence extends to low altitudes and is referred to as 'downward control'. Small changes in the solar radiative forcing may produce small changes in the period and phase of the QBO, but these in turn may produce measurable differences in the wind field. Thus, the QBO may be an amplifier of solar activity variations and a natural conduit of these variations to lower altitudes. To test this hypothesis, we conducted experiments with a 2D version of our Numerical Spectral Model that incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GW). Solar cycle radiance variations (SCRV) are accounted for by changing the radiative heating rate on a logarithmic scale from 0.1% at the surface to 1% at 50 km to 10% at 100 km. With and without SCRV, but with the same GW flux, we then conduct numerical experiments to evaluate the magnitude of the SCAE in the zonal circulation. The numerical results indicate that, under certain conditions, the SCAE is significant and can extend to lower altitudes where the SCRV is small. For a modeled QBO period of 30 months, we find that the seasonal cycle in the solar forcing acts as a strong pacemaker to lock up the phase and period of the QBO. The SCAE then shows up primarily as a distinct but relatively weak amplitude modulation. But with a different QBO period

  20. Rotation, activity, and stellar obliquities in a large uniform sample of Kepler solar analogs

    NASA Astrophysics Data System (ADS)

    Buzasi, Derek; Lezcano, Andy; Preston, Heather L.

    2016-10-01

    In this study, we undertook a deep photometric examination of a narrowly-defined sample of solar analogs in the Kepler field, with the goals of producing a uniform and statistically meaningful sample of such stars, comparing the properties of planet hosts to those of the general stellar population, and examining the behavior of rotation and photometric activity among stars with similar overall physical parameters. We successfully derived photometric activity indicators and rotation periods for 95 planet hosts (Kepler objects of interest [KOIs]) and 954 solar analogs without detected planets; 573 of these rotation periods are reported here for the first time. Rotation periods average roughly 20 d, but the distribution has a wide dispersion, with a tail extending to P > 35 d which appears to be inconsistent with published gyrochronological relations. We observed a weak rotation-activity relation for stars with rotation periods less than about 12 d; for slower rotators, the relation is dominated by scatter. However, we are able to state that the solar activity level derived from Virgo data is consistent with the majority of stars with similar rotation periods in our sample. Finally, our KOI sample is consistently approximately 0.3 dex more variable than our non-KOIs; we ascribe the difference to a selection effect due to low orbital obliquity in the planet-hosting stars and derive a mean obliquity for our sample of χ = 6+5°-6, similar to that seen in the solar system.

  1. Is the O2(a1Δg) Venus nightglow emission controlled by solar activity?

    NASA Astrophysics Data System (ADS)

    Soret, Lauriane; Gérard, Jean-Claude

    2015-12-01

    Several past studies showed that the O2(a1Δg) Venus nightglow emission at 1.27 μm is highly variable on a timescale of hours. We examine whether the intensity of this emission shows a more global trend linked to solar activity.

  2. Discovery of an activity cycle in the solar analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates

    NASA Astrophysics Data System (ADS)

    Flores, M.; González, J. F.; Jaque Arancibia, M.; Buccino, A.; Saffe, C.

    2016-05-01

    Context. Most stellar activity cycles similar to that found in the Sun have been detected by using the chromospheric Ca ii H&K lines as stellar activity proxies. However, it is unclear whether such activity cycles can be identified using other optical lines. Aims: We aim to detect activity cycles in solar-analog stars and determine whether they can be identified through other optical lines, such as Fe II and Balmer lines. We study the solar-analog star HD 45184 using HARPS spectra. The temporal coverage and high quality of the spectra allow us to detect both long- and short-term activity variations. Methods: We analysed the activity signatures of HD 45184 by using 291 HARPS spectra obtained between 2003 and 2014. To search for line-core flux variations, we focused on Ca ii H&K and Balmer Hα and Hβ lines, which are typically used as optical chromospheric activity indicators. We calculated the HARPS-S index from Ca ii H&K lines and converted it into the Mount Wilson scale. In addition, we also considered the equivalent widths of Balmer lines as activity indicators. Moreover, we analysed the possible variability of Fe ii and other metallic lines in the optical spectra. The spectral variations were analysed for periodicity using the Lomb-Scargle periodogram. Results: We report for the first time a long-term 5.14-yr activity cycle in the solar-analog star HD 45184 derived from Mount Wilson S index. This makes HD 45184 one of most similar stars to the Sun with a known activity cycle. The variation is also evident in the first lines of the Balmer series, which do not always show a correlation with activity in solar-type stars. Notably, unlike the solar case, we also found that the equivalent widths of the high photospheric Fe ii lines (4924 Å, 5018 Å and 5169 Å) are modulated (±2 mÅ) by the chromospheric cycle of the star. These metallic lines show variations above 4σ in the rms spectrum, while some Ba ii and Ti ii lines present variations at 3σ level, which

  3. Statistical Analysis of Acoustic Wave Parameters Near Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Rabello-Soares, M. Cristina; Bogart, Richard S.; Scherrer, Philip H.

    2016-08-01

    In order to quantify the influence of magnetic fields on acoustic mode parameters and flows in and around active regions, we analyze the differences in the parameters in magnetically quiet regions nearby an active region (which we call “nearby regions”), compared with those of quiet regions at the same disk locations for which there are no neighboring active regions. We also compare the mode parameters in active regions with those in comparably located quiet regions. Our analysis is based on ring-diagram analysis of all active regions observed by the Helioseismic and Magnetic Imager (HMI) during almost five years. We find that the frequency at which the mode amplitude changes from attenuation to amplification in the quiet nearby regions is around 4.2 mHz, in contrast to the active regions, for which it is about 5.1 mHz. This amplitude enhacement (the “acoustic halo effect”) is as large as that observed in the active regions, and has a very weak dependence on the wave propagation direction. The mode energy difference in nearby regions also changes from a deficit to an excess at around 4.2 mHz, but averages to zero over all modes. The frequency difference in nearby regions increases with increasing frequency until a point at which the frequency shifts turn over sharply, as in active regions. However, this turnover occurs around 4.9 mHz, which is significantly below the acoustic cutoff frequency. Inverting the horizontal flow parameters in the direction of the neigboring active regions, we find flows that are consistent with a model of the thermal energy flow being blocked directly below the active region.

  4. [The human body response to factors related to solar activity variations].

    PubMed

    Dmitrieva, I V; Obridko, V N; Ragul'skaia, M V; Reznikov, A E; Khabarova, O V

    2001-01-01

    The effect of nonstationary solar processes on human organism was studied. Daily measurements of electrical conductivity of 22 biologically active points on human skin, arterial pressure, and pulse frequency of 30 persons were performed, and their subjective sensations were registered. A comparative analysis of the data and variations in environment parameters, such as local A-index, atmospheric pressure, temperature, and indices of cosmic rays indicated a coincidence of their main periods. The conclusion is made that the reaction of the human organism on abrupt solar disturbances is biphasic and that there is a semiannual wave of synchronization of work of internal organs. The results are confirmed by simultaneous measurements in different cities.

  5. Improved Power Conversion Efficiency of Inverted Organic Solar Cells by Incorporating Au Nanorods into Active Layer.

    PubMed

    He, Yeyuan; Liu, Chunyu; Li, Jinfeng; Zhang, Xinyuan; Li, Zhiqi; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-07-29

    This Research Article describes a cooperative plasmonic effect on improving the performance of organic solar cells. When Au nanorods(NRs) are incorporated into the active layers, the designed project shows superior enhanced light absorption behavior comparing with control devices, which leads to the realization of organic solar cell with power conversion efficiency of 6.83%, accounting for 18.9% improvement. Further investigations unravel the influence of plasmonic nanostructures on light trapping, exciton generation, dissociation, and charge recombination and transport inside the thin films devices. Moreover, the introduction of high-conductivity Au NRs improves electrical conductivity of the whole device, which contributes to the enhanced fill factor.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  7. 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.

  8. Ancient cellular structures and modern humans: change of survival strategies before prolonged low solar activity period

    NASA Astrophysics Data System (ADS)

    Ragulskaya, Mariya; Rudenchik, Evgeniy; Gromozova, Elena; Voychuk, Sergei; Kachur, Tatiana

    The study of biotropic effects of modern space weather carries the information about the rhythms and features of adaptation of early biological systems to the outer space influence. The influence of cosmic rays, ultraviolet waves and geomagnetic field on early life has its signs in modern biosphere processes. These phenomena could be experimentally studied on present-day biological objects. Particularly inorganic polyphosphates, so-called "fossil molecules", attracts special attention as the most ancient molecules which arose in inanimate nature and have been accompanying biological objects at all stages of evolution. Polyphosphates-containing graves of yeast's cells of Saccharomyces cerevisiae strain Y-517, , from the Ukrainian Collection of Microorganisms was studied by daily measurements during 2000-2013 years. The IZMIRAN daily data base of physiological parameters dynamics during 2000-2013 years were analyzed simultaneously (25 people). The analysis showed significant simultaneous changes of the statistical parameters of the studied biological systems in 2004 -2006. The similarity of simultaneous changes of adaptation strategies of human organism and the cell structures of Saccharomyces cerevisiae during the 23-24 cycles of solar activity are discussed. This phenomenon could be due to a replacement of bio-effective parameters of space weather during the change from 23rd to 24th solar activity cycle and nonstandard geophysical peculiarities of the 24th solar activity cycle. It could be suggested that the observed similarity arose as the optimization of evolution selection of the living systems in expectation of probable prolonged period of low solar activity (4-6 cycles of solar activity).

  9. The solar cycle variation of the rates of CMEs and related activity

    NASA Technical Reports Server (NTRS)

    Webb, David F.

    1991-01-01

    Coronal mass ejections (CMEs) are an important aspect of the physics of the corona and heliosphere. This paper presents results of a study of occurrence frequencies of CMEs and related activity tracers over more than a complete solar activity cycle. To properly estimate occurrence rates, observed CME rates must be corrected for instrument duty cycles, detection efficiencies away from the skyplane, mass detection thresholds, and geometrical considerations. These corrections are evaluated using CME data from 1976-1989 obtained with the Skylab, SMM and SOLWIND coronagraphs and the Helios-2 photometers. The major results are: (1) the occurrence rate of CMEs tends to track the activity cycle in both amplitude and phase; (2) the corrected rates from different instruments are reasonably consistent; and (3) over the long term, no one class of solar activity tracer is better correlated with CME rate than any other (with the possible exception of type II bursts).

  10. On the Current Solar Magnetic Activity using Its Behavior During the Holocene

    NASA Astrophysics Data System (ADS)

    Inceoglu, Fadil; Simoniello, Rosaria; Faurschou Knudsen, Mads; Karoff, Christoffer; Olsen, Jesper; Turck-Chieze, Sylvaine

    2016-07-01

    Solar modulation potential (SMP) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behavior of the open solar magnetic field over the Holocene period. Using the Greenland Ice Core Project (GRIP) ^{10}Be and IntCal13 ^{14}C records for the overlapping time period spanning between ˜1650 AD to 6600 BC, we first reconstructed the solar modulation potentials and subsequently investigate the statistics of peaks and dips simultaneously occurring in the two SMP reconstructions. Based on the distribution of these events, we propose a method to identify grand minima and maxima periods. We then aim at comparing the Sun's large-scale magnetic field behavior over the last three solar cycles with variations in the SMP reconstruction through the Holocene epoch. To achieve these objectives, we use the IntCal13 ^{14}C data to investigate distinct patterns in the occurrences of grand minima and maxima during the Holocene period. We then check whether these patterns might mimic the recent solar magnetic activity by investigating the evolution of the energy in the Sun's large-scale dipolar magnetic field using the Wilcox Solar Observatory data. The cosmogenic radionuclide data analysis shows that ˜71 % of grand maxima during the period from 6600 BC to 1650 AD were followed by a grand minimum. The characteristics of the occurrences of grand maxima and minima are consistent with the scenario in which the dynamical non-linearity induced by the Lorentz force leads the Sun to act as a relaxation oscillator. This finding implies that the probability for these events to occur is non-uniformly distributed in time, as there is a memory in their driving mechanism, which can be identified via the back-reaction of the Lorentz force.

  11. Energetic proton irradiation history of the HED parent body regolith and implications for ancient solar activity

    NASA Astrophysics Data System (ADS)

    Rao, M. N.; Garrison, D. H.; Palma, R. L.; Bogard, D. D.

    1997-07-01

    Previous studies have shown that the Kapoeta howardite, as well as several other meteorites, contain excess concentrations of cosmogenic neon in the darkened, solar-irradiated phase compared to the light, non-irradiated phase. The two explanations offered for the nuclear production of these Ne excesses in the parent body regolith are either from galactic particle (GCR) irradiation or from a greatly enhanced flux of energetic solar protons (SCR), as compared to the recent solar flux. Combining new isotopic data we obtained on acid-etched, separated feldspar from Kapoeta light and dark phases with literature data, we show that the cosmogenic 21Ne /22Ne ratio of light phase feldspar (0.80) is consistent with only GCR irradiation in space for ~3 Myr. However, the 21Ne/22Ne ratio (0.68) derived for irradiation of dark phase feldspar in the Kapoeta regolith indicates that cosmogenic Ne was produced in roughly equal proportions from galactic and solar protons. Considering a simple model of an immature Kapoeta parent body regolith, the duration of this early galactic exposure was only ~3-6 Myr, which would be an upper limit to the solar exposure time of individual grains. Concentrations of cosmogenic 21Ne in pyroxene separates and of cosmogenic 126Xe in both feldspar and pyroxene are consistent with this interpretation. The near-surface irradiation time of individual grains in the Kapoeta regolith probably varied considerably due to regolith mixing to an average GCR irradiation depth of ~10 cm. Because of the very different depth scales for production of solar ~Fe tracks, SCR Ne, and GCR Ne, the actual regolith exposure times for average grains probably differed correspondingly. However, both the SCR 21Ne and solar track ages appear to be longer because of enhanced production by early solar activity. The SCR/GCR production ratio of 21Ne inferred from the Kapoeta data is larger by a at least a factor of 10 and possibly as much as a factor of ~50 compared to recent solar

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

    SciTech Connect

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

    2015-12-29

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

  13. Solar activity variations of nocturnal thermospheric meridional winds over Indian longitude sector

    NASA Astrophysics Data System (ADS)

    Madhav Haridas, M. K.; Manju, G.; Arunamani, T.

    2016-09-01

    The night time F-layer base height information from ionosondes located at two equatorial stations Trivandrum (TRV 8.5°N, 77°E) and Sriharikota (SHAR 13.7°N, 80.2°E) spanning over two decades are used to derive the climatology of equatorial nocturnal Thermospheric Meridional Winds (TMWs) prevailing during High Solar Activity (HSA) and Low Solar Activity (LSA) epochs. The important inferences from the analysis are 1) Increase in mean equatorward winds observed during LSA compared to HSA during pre midnight hours; 25 m/s for VE (Vernal Equinox) and 20 m/s for SS (Summer Solstice), AE (autumnal Equinox) and WS (Winter Solstice). 2) Mean wind response to Solar Flux Unit (SFU) is established quantitatively for all seasons for pre-midnight hours; rate of increase is 0.25 m/s/SFU for VE, 0.2 m/s/SFU for SS and WS and 0.08 m/s/SFU for AE. 3) Theoretical estimates of winds for the two epochs are performed and indicate the role of ion drag forcing as a major factor influencing TMWs. 4) Observed magnitude of winds and rate of flux dependencies are compared to thermospheric wind models. 5) Equinoctial asymmetry in TMWs is observed for HSA at certain times, with more equatorward winds during AE. These observations lend a potential to parameterize the wind components and effectively model the winds, catering to solar activity variations.

  14. TEC variation during high and low solar activities over South American sector

    NASA Astrophysics Data System (ADS)

    Jonah, O. F.; de Paula, E. R.; Muella, M. T. A. H.; Dutra, S. L. G.; Kherani, E. A.; Negreti, P. M. S.; Otsuka, Y.

    2015-12-01

    Using dual frequency GPS receivers in the South American sector, the measurement of absolute ionospheric Total Electron Content (TEC) has been estimated applying the Nagoya ionospheric model for both the years of 2009 and 2001, which represent low and high solar activities, respectively. The diurnal, day-to-day, monthly, seasonal, latitudinal and longitudinal variations of TEC were studied for equatorial and low latitude regions of South America. The strength and characteristics of the Equatorial Ionization Anomaly (EIA) were equally analyzed. The analyses reveal the diurnal, seasonal and semidiurnal TEC variation, as well as the nighttime variability during the low and high solar activities. Wavelet power spectra analysis was employed to check the periodicities of the TEC data, F10.7 and zonal and meridional wind velocities measured by Meteor radar at ∼100 km altitude. Periods such as 27, 16, 8-10, 1-5 days were found to be dominant in the zonal and meridional wind velocity corresponding with those of TEC periodicities. Hence, besides the solar radiation, we suggest that there are contributions of tides and planetary waves in spatial and temporal TEC enhancement and variations during the geomagnetic quiet periods of both solar activities.

  15. A low upper limit on the subsurface rise speed of solar active regions

    PubMed Central

    Birch, Aaron C.; Schunker, Hannah; Braun, Douglas C.; Cameron, Robert; Gizon, Laurent; Löptien, Björn; Rempel, Matthias

    2016-01-01

    Magnetic field emerges at the surface of the Sun as sunspots and active regions. This process generates a poloidal magnetic field from a rising toroidal flux tube; it is a crucial but poorly understood aspect of the solar dynamo. The emergence of magnetic field is also important because it is a key driver of solar activity. We show that measurements of horizontal flows at the solar surface around emerging active regions, in combination with numerical simulations of solar magnetoconvection, can constrain the subsurface rise speed of emerging magnetic flux. The observed flows imply that the rise speed of the magnetic field is no larger than 150 m/s at a depth of 20 Mm, that is, well below the prediction of the (standard) thin flux tube model but in the range expected for convective velocities at this depth. We conclude that convective flows control the dynamics of rising flux tubes in the upper layers of the Sun and cannot be neglected in models of flux emergence. PMID:27453947

  16. The Impact of Level of Solar Activity on Mortality by Cause in Longtime Period

    NASA Astrophysics Data System (ADS)

    Podolska, Katerina

    2014-05-01

    The aim of this presentation is to show the dependence of the intensity of mortality in the Czech Republic, according to the chosen causes of death according to ICD-10, on the solar activity during the increasing and decreasing phase of the solar cycle No.23 in the period 1994-2011. We use the methods of multivariate statistical analysis. The typology of time profiles for the causes of death is identified with the help of cluster analysis using time. The solar activity is represented by the indices R, Kp, F10.7 and Dst, and also by the height of the F2 layer and TEC for the Czech Republic. There are investigated groups of causes of death according to ICD-10 II. Neoplasms, VI. Diseases of the nervous system, XII. Diseases of the skin and subcutaneous tissue and XVII. Congenital malformations, deformations and chromosomal abnormalities. The correlation between the intensity of mortality from cardiovascular disease e.g. I21 (acute myocardial infarction) and I64 (stroke) and birth defect e.g. Q91 (Edwards' and Pataus' syndrom) and the solar activity parameters is discovered, as well as a stronger dependence on the height of the F2 layer and TEC. We also explored the influence of the above parameters on mortality by causes on degenerative diseases. Typology of time profiles for these causes of death are identified by cluster analysis using time and have found large differences between diagnoses.

  17. A low upper limit on the subsurface rise speed of solar active regions.

    PubMed

    Birch, Aaron C; Schunker, Hannah; Braun, Douglas C; Cameron, Robert; Gizon, Laurent; Löptien, Björn; Rempel, Matthias

    2016-07-01

    Magnetic field emerges at the surface of the Sun as sunspots and active regions. This process generates a poloidal magnetic field from a rising toroidal flux tube; it is a crucial but poorly understood aspect of the solar dynamo. The emergence of magnetic field is also important because it is a key driver of solar activity. We show that measurements of horizontal flows at the solar surface around emerging active regions, in combination with numerical simulations of solar magnetoconvection, can constrain the subsurface rise speed of emerging magnetic flux. The observed flows imply that the rise speed of the magnetic field is no larger than 150 m/s at a depth of 20 Mm, that is, well below the prediction of the (standard) thin flux tube model but in the range expected for convective velocities at this depth. We conclude that convective flows control the dynamics of rising flux tubes in the upper layers of the Sun and cannot be neglected in models of flux emergence.

  18. The QBO and weak external forcing by solar activity: A three dimensional model study

    NASA Technical Reports Server (NTRS)

    Dameris, M.; Ebel, A.

    1989-01-01

    A better understanding is attempted of the physical mechanisms leading to significant correlations between oscillations in the lower and middle stratosphere and solar variability associated with the sun's rotation. A global 3-d mechanistic model of the middle atmosphere is employed to investigate the effects of minor artificially induced perturbations. The aim is to explore the physical mechanisms of the dynamical response especially of the stratosphere to weak external forcing as it may result from UV flux changes due to solar rotation. First results of numerical experiments dealing about the external forcing of the middle atmosphere by solar activity were presented elsewhere. Different numerical studies regarding the excitation and propagation of weak perturbations have been continued since then. The model calculations presented are made to investigate the influence of the quasi-biennial oscillation (QBO) on the dynamical response of the middle atmosphere to weak perturbations by employing different initial wind fields which represent the west and east phase of the QBO.

  19. Coronal activity below 2 solar radii - 1980 February 15-17

    NASA Technical Reports Server (NTRS)

    Fisher, R. R.; Poland, A. I.

    1981-01-01

    Coronal observations concerning the area between the solar surface and 2.0 solar radii can now be conducted by making use of a new ground-based K-coronameter and a prominence monitor on Mauna Loa in Hawaii. Observations made by the K-coronameter on three consecutive days surrounding the eclipse of 1980 February 16 show that the solar corona was very active during this time. Definite changes occurred between each day's observations. During one period of K-coronameter observations (1980 February 15) a coronal transient was observed to move through the coronameter's field of view. A description is presented of the general changes which occurred in the corona during this period, taking into account the coronal transient observed by the prominence monitor and K-coronameter. The most important aspects of these new observations pertain to the relationship between the H alpha prominence and the surrounding coronal material.

  20. Active thermal control for the 1.8-m primary mirror of the solar telescope CLST

    NASA Astrophysics Data System (ADS)

    Liu, Yangyi; Gu, Naiting; Li, Cheng; Cheng, Yuntao; Yao, Benxi; Wang, Zhiyong; Rao, Changhui

    2016-07-01

    The 1.8-m primary mirror of solar telescope is heated by the solar radiation and introduce harmful mirror seeing degrading the imaging quality. For the Chinese Large Solar Telescope (CLST), the thermal requirement based on the quantitative evaluation on mirror seeing effect shows that the temperature rise on mirror surface should be within 1 kelvin. To meet the requirement, an active thermal control system design for the CLST primary mirror is proposed, and realized on the subscale prototype of the CLST. The experimental results show that the temperature on the mirror surface is well controlled. The average and maximum thermal controlled error are less than 0.3 and 0.7 kelvins respectively, which completely meets the requirements.

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

    NASA Technical Reports Server (NTRS)

    Kazimirovsky, E. S.

    1989-01-01

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

  2. The impact of solar radiation and solar activity on climate variability after the end of the last glaciation

    NASA Astrophysics Data System (ADS)

    Dergachev, V. A.

    2016-12-01

    This paper analyzes climate changes since the end of the last glaciations 19-20 thousand years ago, including the modern warm interglacial Holocene age, which started about 11.5 thousand years ago. The connection between the impact of the orbital effect and solar activity on the Earth's climate is studied. This is important for estimation of the duration of the modern interglacial period. It is shown that there is significant inconsistency between temperature variations in Holocene, which is deduced from the large amount of recently obtained indirect data and the temperatures reproduced in the climate models. The trends of climate cooling in the Holocene on the whole and during the last 2000 years are investigated.

  3. PERSPECTIVE: Low solar activity is blamed for winter chill over Europe

    NASA Astrophysics Data System (ADS)

    Benestad, Rasmus E.

    2010-06-01

    Throughout recent centuries, there have been a large number of studies of the relationship between solar activity and various aspects of climate, and yet this question is still not entirely settled. In a recent study, Lockwood et al (2010) argue that the occurrence of persistent wintertime blocking events (periods with persistent high sea level pressure over a certain region) over the eastern Atlantic, and hence chilly winters over northern Europe, are linked to low solar activity. Is this then a breakthrough in our understanding of our climate? The Wolf sunspot number, which dates back to Galileo's invention of the telescope in the 17th century, represents one of our longest geophysical data records. Galileo was also involved in building the first barometers and thermometers around that period. Hence, the 17th century represents the start of instrumental measurements of weather and climate, and there are indeed historical records of speculations or studies on the link between changes in the sun and conditions on Earth dating from that time (Helland-Hansen and Nansen 1920). One notorious problem with many previous studies was that relationships established over the calibration interval subsequently broke down. There was a period in the mid-20th century when little work was done on solar activity and climate, but solar activity was considered a real forcing factor before 1920. With the advent of frontal theory, orbital forcing theory, and stronger awareness of the implications of enhanced greenhouse gas concentrations, the support for solar forcing seemed to have diminished in the climatology community by the mid-20th century (Monin 1972). But non-stationary relationships, the chaotic character of climate, weak effects, and lack of a physical understanding behind such a link, can also explain the low support for solar forcing at that time. For a long time, it was not established whether more sunspots meant a brighter or dimmer sun (the answer is brighter), and then

  4. Heliophysics: Evolving Solar Activity and the Climates of Space and Earth

    NASA Astrophysics Data System (ADS)

    Schrijver, Carolus J.; Siscoe, George L.

    2012-01-01

    Preface; 1. Interconnectedness in heliophysics Carolus J. Schrijver and George L. Siscoe; 2. Long-term evolution of magnetic activity of Sun-like stars Carolus J. Schrijver; 3. Formation and early evolution of stars and proto-planetary disks Lee W. Hartmann; 4. Planetary habitability on astronomical time scales Donald E. Brownlee; 5. Solar internal flows and dynamo action Mark S. Miesch; 6. Modeling solar and stellar dynamos Paul Charbonneau; 7. Planetary fields and dynamos Ulrich R. Christensen; 8. The structure and evolution of the 3D solar wind John T. Gosling; 9. The heliosphere and cosmic rays J. Randy Jokipii; 10. Solar spectral irradiance: measurements and models Judith L. Lean and Thomas N. Woods; 11. Astrophysical influences on planetary climate systems Juerg Beer; 12. Evaluating the drivers of Earth's climate system Thomas J. Crowley; 13. Ionospheres of the terrestrial planets Stanley C. Solomon; 14. Long-term evolution of the geospace climate Jan J. Sojka; 15. Waves and transport processes in atmospheres and oceans Richard L. Walterscheid; 16. Solar variability, climate, and atmospheric photochemistry Guy P. Brasseur, Daniel Marsch and Hauke Schmidt; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

  5. Heliophysics: Evolving Solar Activity and the Climates of Space and Earth

    NASA Astrophysics Data System (ADS)

    Schrijver, Carolus J.; Siscoe, George L.

    2010-09-01

    Preface; 1. Interconnectedness in heliophysics Carolus J. Schrijver and George L. Siscoe; 2. Long-term evolution of magnetic activity of Sun-like stars Carolus J. Schrijver; 3. Formation and early evolution of stars and proto-planetary disks Lee W. Hartmann; 4. Planetary habitability on astronomical time scales Donald E. Brownlee; 5. Solar internal flows and dynamo action Mark S. Miesch; 6. Modeling solar and stellar dynamos Paul Charbonneau; 7. Planetary fields and dynamos Ulrich R. Christensen; 8. The structure and evolution of the 3D solar wind John T. Gosling; 9. The heliosphere and cosmic rays J. Randy Jokipii; 10. Solar spectral irradiance: measurements and models Judith L. Lean and Thomas N. Woods; 11. Astrophysical influences on planetary climate systems Juerg Beer; 12. Evaluating the drivers of Earth's climate system Thomas J. Crowley; 13. Ionospheres of the terrestrial planets Stanley C. Solomon; 14. Long-term evolution of the geospace climate Jan J. Sojka; 15. Waves and transport processes in atmospheres and oceans Richard L. Walterscheid; 16. Solar variability, climate, and atmospheric photochemistry Guy P. Brasseur, Daniel Marsch and Hauke Schmidt; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

  6. Reexamination of the Coronal Index of Solar Activity

    DTIC Science & Technology

    2005-08-25

    characterizes photospheric activity. At present, four coronal 0148-0227/05/2005JA011146$09.00 stations (Lomnický’ Stit (Slovakia), Norikura (Japan...de la couronne solaire en dehors des 6clipses, 1965) data at Lomnický’ Stit tracks the standard measures of Z Astrophys., 5, 73. photospheric activity...Astrophys., 35, 213. Hanscom AFB, MA 01731-3010, USA. (edward.cliver@hanscom.af.mil) d’Azambuja, H. L. (1947), Donn6es Nouvelles sur I’Activit6 Solaire , L

  7. Photospheric and chromospheric magnetic activity of seismic solar analogs. Observational inputs on the solar-stellar connection from Kepler and Hermes

    NASA Astrophysics Data System (ADS)

    Salabert, D.; García, R. A.; Beck, P. G.; Egeland, R.; Pallé, P. L.; Mathur, S.; Metcalfe, T. S.; do Nascimento, J.-D., Jr.; Ceillier, T.; Andersen, M. F.; Triviño Hage, A.

    2016-11-01

    We identify a set of 18 solar analogs among the seismic sample of solar-like stars observed by the Kepler satellite rotating between 10 and 40 days. This set is constructed using the asteroseismic stellar properties derived using either the global oscillation properties or the individual acoustic frequencies. We measure the magnetic activity properties of these stars using observations collected by the photometric Kepler satellite and by the ground-based, high-resolution Hermes spectrograph mounted on the Mercator telescope. The photospheric (Sph) and chromospheric (S index) magnetic activity levels of these seismic solar analogs are estimated and compared in relation to the solar activity. We show that the activity of the Sun is comparable to the activity of the seismic solar analogs, within the maximum-to-minimum temporal variations of the 11-yr solar activity cycle 23. In agreement with previous studies, the youngest stars and fastest rotators in our sample are actually the most active. The activity of stars older than the Sun seems to not evolve much with age. Furthermore, the comparison of the photospheric, Sph, with the well-established chromospheric, S index, indicates that the Sph index can be used to provide a suitable magnetic activity proxy which can be easily estimated for a large number of stars from space photometric observations. Based on observations collected by the NASA Kepler space telescope and the Hermes spectrograph mounted on the 1.2 m Mercator telescope at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

  8. OBSERVATIONAL ASPECTS OF THE THREE-DIMENSIONAL CORONAL STRUCTURE OVER A SOLAR ACTIVITY CYCLE

    SciTech Connect

    Morgan, Huw; Habbal, Shadia Rifai

    2010-02-10

    Solar rotational tomography is applied to almost eleven years of Large Angle Spectrometric Coronagraph C2/Solar and Heliospheric Observatory data, revealing for the first time the behavior of the large-scale coronal density structures, also known as streamers, over almost a full solar activity cycle. This study gives an overview of the main results of this project. (1) Streamers are most often shaped as extended, narrow plasma sheets. The sheets can be extremely narrow at times (<=0.14 x 10{sup 6} km at 4 R{sub sun}). This is over twice their heliocentric angular thickness at 1 AU. (2) At most times outside the height of solar maximum, there are two separate stable large helmet streamer belts extending from mid-latitudes (in both north and south). At solar minimum, the streamers converge and join near the equator, giving the impression of a single large helmet streamer. Outside of solar minimum, the two streamers do not join, forming separate high-density sheets in the extended corona (one in the north, another in the south). At solar maximum, streamers rise radially from their source regions, while during the ascending and descending activity phases, streamers are skewed toward the equator. (3) For most of the activity cycle, streamers share the same latitudinal extent as filaments on the disk, showing that large-scale stable streamers are closely linked to the same large-scale photospheric magnetic configuration, which give rise to large filaments. (4) The poleward footpoints of the streamers are often above crown polar filaments and the equatorial footpoints are above filaments or active regions (or above the photospheric neutral lines which underlie these structures). The high-density structures arising from the equatorial active regions either rise and form the equatorial footpoints of mid-latitude quiescent streamers, or form unstable streamers at the equator, not connected to the quiescent streamer structure at higher latitude (so there are often three

  9. Downward Link of Solar Activity Variations Through Wave Driven Equatorial Oscillations (QBO and SAO)

    NASA Technical Reports Server (NTRS)

    Mengel, J. G.; Mayr, H. G.; Chan, K. L.; Porter, H. S.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Signatures of the 11-year solar activity/irradiance cycle are observed in the Quasi Biennial Oscillation (QBO) of the lower stratosphere. At these altitudes, the QBO is understood to be the result of "downward control" exerted by the wave mean flow interactions that drive the phenomenon. It is reasonable then to speculate that the QBO is a natural conduit to lower altitudes of solar activity variations in radiance (SAV). To test this hypothesis, we conducted experiments with a 2D version of our Numerical Spectral Model that incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GW). To account for the SAV, we change the solar heating rate on a logarithmic scale from 0.1% at the surface to 1% at 50 kin to 10% at 100 km. With the same GW flux, we then conduct numerical experiments to evaluate the magnitude of the solar activity irradiance effect (SAE) on the zonal circulation at low latitudes. The numerical results obtained show that, under certain conditions, the SAE is significant in the zonal circulation and does extend to lower altitudes where the SAV is small. The differences in the wind velocities can be as large as 5 m/s at 20 kin. We carried out two numerical experiments with integrations over more than 20 years: 1) With the QBO period "tuned" to be 30 months, of academic interest but instructive, the seasonal cycle in the solar forcing [through the Semi-annual Oscillation (SAO)] acts as a strong pacemaker to produce a firm lock on the period and phase of the QBO. The SAE then shows up primarily as a distinct but relatively weak amplitude modulation. 2) With the QBO period between 30 and 34 (or less than 30, presumably) months, the seasonal phase lock is weak compared with (1). The SAV in the seasonal cycle then causes variations in the QBO period and phase, and this amplifies the SAE to produce relatively large variations in the wind field. We conclude that, under realistic conditions as in (2), the solar seasonal forcing, with

  10. Kinaesthetic Learning Activities and Learning about Solar Cells

    ERIC Educational Resources Information Center

    Richards, A. J.; Etkina, Eugenia

    2013-01-01

    Kinaesthetic learning activities (KLAs) can be a valuable pedagogical tool for physics instructors. They have been shown to increase engagement, encourage participation and improve learning outcomes. This paper details several KLAs developed at Rutgers University for inclusion in an instructional unit about semiconductors, p-n junctions and solar…

  11. Abrupt Changes of the Photospheric Magnetic Field in Active Regions and the Impulsive Phase of Solar Flares (Preprint)

    DTIC Science & Technology

    2012-08-09

    PHASE OF SOLAR FLARES (PREPRINT) E. W. Cliver, et al. 9 August 2012 Interim Report APPROVED FOR PUBLIC...the Impulsive Phase of Solar Flares (Preprint) 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) 5d. PROJECT NUMBER...public release; distribution is unlimited. Abrupt Changes of the Photospheric Magnetic Field in Active Regions and the Impulsive Phase of Solar

  12. MAX 1991. The active sun: A plan for pursuing the study of the active sun at the time of the next maximum in solar activity, January 1985

    NASA Technical Reports Server (NTRS)

    Acton, L.

    1989-01-01

    The results of the discusions of a working group for the definition of a program for the forthcoming crest of solar activity, 1990 to 1993 are presented. The MAX '91 program described are intended to achieve important scientific goals within the context of the natural solar variability. The heart of the MAX '91 program is a series of campaigns oriented towards specific scientific problems, and taking place in the solar maximum period 1990 to 1993. These campaigns will take advantage of the load-carrying capability of the Space Shuttle to fly instruments with observational capabilities very different from those of the Solar Maximum Mission. Various combinations of instruments appropriate to the specific scientific problem of a given campaign would be flown on a Shuttle sortie mission.

  13. [Variation of microflora and enzyme activity in continuous cropping cucumber soil in solar greenhouse].

    PubMed

    Ma, Yunhua; Wei, Min; Wang, Xiufeng

    2004-06-01

    Variation of microflora and enzyme activity in solar greenhouse soil continuous cropping for 1, 3, 5, 7, 9 years was studied, in addition to the relationship between soil properities and microflora and enzyme activity. The results showed that number of bacteria, actinomyce as well as total microflora showed a trend with a saddle-shaped curve, while the number of fungi appeared an liner increase. Continuous cropping soil microflora shifted from bacteria type to fungi type significantly, of which Ammoniation bacterium and Fusarium oxysporum were main physiology groups. Path analysis results showed that microelements (Mn, Cu, Fe), organic matter, available N and bulk density are main restricted factors of soil microflora and enzyme activity in solar greenhouse.

  14. Effects of the intense solar activity of March/June 1991 observed in the outer heliosphere

    NASA Technical Reports Server (NTRS)

    Mcdonald, F. B.; Barnes, A.; Burlaga, L. F.; Gazis, P.; Mihalov, J.; Selesnick, R. S.

    1994-01-01

    The properties of the large-scale global merged interaction region (GMIR) generated by the intense solar events of March and June 1991 are studied using the available solar wind, interplanetary magnetic field, and energetic particle data from the observing network of Pioneer 10 and Voyagers 1 and 2 in the outer heliosphere. At heliocentric distances extending to 55 AU the delayed effects of this enhanced solar activity are observed in the form of large inceases in the solar wind velocity and interplanetary magnetic field and significant decreases in the galactic cosmic ray intensity. For low-energy ions (5-MeV protons) there was a single long-lived event extending over a period of some 6 months. Near the strongest interplanetary disturbances the H and He spectra are best represented by similar exponentials in momentum/nucleon (i.e., particle velocity at these at these energies). Over the rest of the event the characteristic momentum for He, (P(sub 0))(sub He) is generally approximately 0.66 for hydrogen. These spectra and the consistently low H/He ratio (25.3) at 2 MeV/nucleon closely resemble that observed in corrotating interaction regions events. Despite the strong north/south asymmetry in the solar activity, the interplanetary disturbances produced the same net decrease in the galactic cosmic ray intensity of ions greater than 70 MeV at the three widely separated spacecraft when the effects of the long-term recovery are taken into account. A comparison of the relative intensity of MeV ions at these three spacecraft suggest that the most intense solar events occurred on the back side of the Sun in time periods adjacent to the March and June episodes of solar activity. It is argued that this GMIR as a system is responsible for the low-frequency radio emission observed by the Voyager Plasma Wave experiment some 1.46 years after the onset of the March 1991 activity.

  15. Chromospherically Active Stars in the RAVE Survey. II. Young Dwarfs in the Solar Neighborhood

    NASA Astrophysics Data System (ADS)

    Žerjal, M.; Zwitter, T.; Matijevič, G.; Grebel, E. K.; Kordopatis, G.; Munari, U.; Seabroke, G.; Steinmetz, M.; Wojno, J.; Bienaymé, O.; Bland-Hawthorn, J.; Conrad, C.; Freeman, K. C.; Gibson, B. K.; Gilmore, G.; Kunder, A.; Navarro, J.; Parker, Q. A.; Reid, W.; Siviero, A.; Watson, F. G.; Wyse, R. F. G.

    2017-01-01

    A large sample of over 38,000 chromospherically active candidate solar-like stars and cooler dwarfs from the RAVE survey is addressed in this paper. An improved activity identification with respect to the previous study was introduced to build a catalog of field stars in the solar neighborhood with an excess emission flux in the calcium infrared triplet wavelength region. The central result of this work is the calibration of the age–activity relation for main-sequence dwarfs in a range from a few 10 {Myr} up to a few Gyr. It enabled an order of magnitude age estimation of the entire active sample. Almost 15,000 stars are shown to be younger than 1 {Gyr} and ∼2000 younger than 100 {Myr}. The young age of the most active stars is confirmed by their position off the main sequence in the J ‑ K versus {N}{UV}-V diagram showing strong ultraviolet excess, mid-infrared excess in the J ‑ K versus {W}1-{W}2 diagram, and very cool temperatures (J-K> 0.7). They overlap with the reference pre-main-sequence RAVE stars often displaying X-ray emission. The activity level increasing with the color reveals their different nature from the solar-like stars and probably represents an underlying dynamo-generating magnetic fields in cool stars. Of the RAVE objects from DR5, 50% are found in the TGAS catalog and supplemented with accurate parallaxes and proper motions by Gaia. This makes the database of a large number of young stars in a combination with RAVE’s radial velocities directly useful as a tracer of the very recent large-scale star formation history in the solar neighborhood. The data are available online in the Vizier database.

  16. Sub- and Quasi-Centurial Cycles in Solar and Geomagnetic Activity Data Series

    NASA Astrophysics Data System (ADS)

    Komitov, B.; Sello, S.; Duchlev, P.; Dechev, M.; Penev, K.; Koleva, K.

    2016-07-01

    The subject of this paper is the existence and stability of solar cycles with durations in the range of 20-250 years. Five types of data series are used: 1) the Zurich series (1749-2009 AD), the mean annual International sunspot number Ri, 2) the Group sunspot number series Rh (1610-1995 AD), 3) the simulated extended sunspot number from Extended time series of Solar Activity Indices (ESAI) (1090-2002 AD), 4) the simulated extended geomagnetic aa-index from ESAI (1099-2002 AD), 5) the Meudon filament series (1919-1991 AD). Two principally independent methods of time series analysis are used: the T-R periodogram analysis (both in standard and ``scanning window'' regimes) and the wavelet-analysis. The obtained results are very similar. A strong cycle with a mean duration of 55-60 years is found to exist in all series. On the other hand, a strong and stable quasi 110-120 years and ˜200-year cycles are obtained in all of these series except in the Ri one. The high importance of the long term solar activity dynamics for the aims of solar dynamo modeling and predictions is especially noted.

  17. Tragaldabas: a muon ground-based detector for the study of the solar activity; first observations

    NASA Astrophysics Data System (ADS)

    José Blanco, Juan

    2016-04-01

    A new RPC-based cosmic ray detector, TRAGALDABAS (acronym of "TRAsGo for the AnaLysis of the nuclear matter Decay, the Atmosphere, the earth's B-field And the Solar activity") has been installed at the Univ. of Santiago de Compostela, Spain (N:42°52'34",W:8°33'37"). The detector, in its present layout, consists of three 1.8 m2 planes of three 1mm-gap glass RPCs. Each plane is readout with 120 pads with grounded guard electrodes between them to minimize the crosstalk noise. The main performances of the detectors are: an arrival time resolution of about ~300 ps, a tracking angular resolution below 3°, a detection efficiency close to 1, and a solid angle acceptance of ~5 srad. TRAGALDABAS will be able to monitor the cosmic ray low energy component strongly modulated by solar activity by mean the observation of secondary muons from the interaction between cosmic rays and atmospheric molecules. Its cadence and its angular resolution will allow to study in detail, small variations in cosmic ray anisotropy. These variations can be a key parameter to understand the effect of solar disturbances on the propagation of cosmic ray in the inner heliosphere and, maybe, provide a new tool for space weather analysis. In this work first TRAGALDABAS observations of solar events are shown

  18. Dynamo Sensitivity in Solar Analogs with 50 Years of Ca II H & K Activity

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Soon, Willie H.; Baliunas, Sallie L.; Hall, Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.

    2016-05-01

    The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11-year cycle is also manifest in the variations of emission in the Ca II H & K line cores, due to non-thermal (i.e. magnetic) heating in the lower chromosphere. The large variation in Ca II H & K emission allows for study of the patterns of long-term variability in other stars thanks to synoptic monitoring with the Mount Wilson Observatory HK photometers (1966-2003) and Lowell Observatory Solar-Stellar Spectrograph (1994-present). Overlapping measurements for a set of 27 nearby solar-analog (spectral types G0-G5) stars were used to calibrate the two instruments and construct time series of magnetic activity up to 50 years in length. Precise properties of fundamental importance to the dynamo are available from Hipparcos, the Geneva-Copenhagen Survey, and CHARA interferometry. Using these long time series and measurements of fundamental properties, we do a comparative study of stellar "twins" to explore the sensitivity of the stellar dynamo to small changes to structure, rotation, and composition. We also compare this sample to the Sun and find hints that the regular periodic variability of the solar cycle may be rare among its nearest neighbors in parameter space.

  19. Dynamo Sensitivity In Solar Analogs With 50 Years Of Ca II H & K Activity

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall, Jeffrey C.; Pevtsov, Alexei A.; Henry, Gregory W.

    2016-09-01

    The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11-year cycle is also manifest in the variations of emission in the Ca II H & K line cores, due to non-thermal (i.e. magnetic) heating in the lower chromosphere. The large variation in Ca II H & K emission allows for study of the patterns of long-term variability in other stars thanks to synoptic monitoring with the Mount Wilson Observatory HK photometers (1966-2003) and Lowell Observatory Solar-Stellar Spectrograph (1994-present). Overlapping measurements for a set of 27 nearby solar-analog (spectral types G0-G5) stars were used to calibrate the two instruments and construct time series of magnetic activity up to 50 years in length. Precise properties of fundamental importance to the dynamo are available from Hipparcos, the Geneva-Copenhagen Survey, and CHARA interferometry. Using these long time series and measurements of fundamental properties, we do a comparative study of stellar "twins" to explore the sensitivity of the stellar dynamo to small changes to structure, rotation, and composition. We also compare this sample to the Sun and find hints that the regular periodic variability of the solar cycle may be rare among its nearest neighbors in parameter space.

  20. Toward bulk heterojunction polymer solar cells with thermally stable active layer morphology

    NASA Astrophysics Data System (ADS)

    Cardinaletti, Ilaria; Kesters, Jurgen; Bertho, Sabine; Conings, Bert; Piersimoni, Fortunato; D'Haen, Jan; Lutsen, Laurence; Nesladek, Milos; Van Mele, Bruno; Van Assche, Guy; Vandewal, Koen; Salleo, Alberto; Vanderzande, Dirk; Maes, Wouter; Manca, Jean V.

    2014-01-01

    When state-of-the-art bulk heterojunction organic solar cells with ideal morphology are exposed to prolonged storage or operation at elevated temperatures, a thermally induced disruption of the active layer blend can occur, in the form of a separation of donor and acceptor domains, leading to diminished photovoltaic performance. Toward the long-term use of organic solar cells in real-life conditions, an important challenge is, therefore, the development of devices with a thermally stable active layer morphology. Several routes are being explored, ranging from the use of high glass transition temperature, cross-linkable and/or side-chain functionalized donor and acceptor materials, to light-induced dimerization of the fullerene acceptor. A better fundamental understanding of the nature and underlying mechanisms of the phase separation and stabilization effects has been obtained through a variety of analytical, thermal analysis, and electro-optical techniques. Accelerated aging systems have been used to study the degradation kinetics of bulk heterojunction solar cells in situ at various temperatures to obtain aging models predicting solar cell lifetime. The following contribution gives an overview of the current insights regarding the intrinsic thermally induced aging effects and the proposed solutions, illustrated by examples of our own research groups.

  1. Ionospheric Response to a Sudden Stratospheric Warming at High Solar Activity

    NASA Astrophysics Data System (ADS)

    Fuller-Rowell, T. J.; Fang, T.; Wang, H.; Wu, F.; Akmaev, R. A.

    2013-12-01

    The recent solar minimum has been an ideal opportunity to study the impact of lower atmosphere dynamics on the thermosphere and ionosphere. During January 2009, for instance, the response to a particularly large sudden stratospheric warming revealed large changes in the vertical plasma drift at the magnetic equator. The response in total electron content showed a 50% increase in the morning hours and a 50% decrease in the afternoon, compared to the typical diurnal variation. Modeling the period enable the physical processes to be unraveled. The change appeared to be in part due to a change in phase of the upward propagating semi-diurnal migrating tide. Numerical simulations have been performed to determine the likely response of the upper atmosphere if this particular stratospheric warming had occurred at higher solar activity. Theory might suggest the wind fields reaching the lower thermosphere dynamo region would be similar, so the changes in the electric fields would be more controlled by the plasma density and conductivity changes. The numerical simulation shed light on the likely response and whether the changes if plasma density would likely be discernable from other sources of solar and geomagnetic variability at high solar activity.

  2. Design of Bicontinuous Donor/Acceptor Morphologies for Use as Organic Solar Cell Active Layers

    NASA Astrophysics Data System (ADS)

    Kipp, Dylan; Mok, Jorge; Verduzco, Rafael; Ganesan, Venkat

    Two of the primary challenges limiting the marketability of organic solar cells are i) the smaller device efficiency of the organic solar cell relative to the conventional silicon-based solar cell and ii) the long term thermal instability of the device active layer. The achievement of equilibrium donor/acceptor morphologies with the characteristics believed to yield high device performance characteristics could address each of these two challenges. In this work, we present the results of a combined simulations and experiments-based approach to investigate if a conjugated BCP additive can be used to control the self-assembled morphologies taken on by conjugated polymer/PCBM mixtures. First, we use single chain in mean field Monte Carlo simulations to identify regions within the conjugated polymer/PCBM composition space in which addition of copolymers can lead to bicontinuous equilibrium morphologies with high interfacial areas and nanoscale dimensions. Second, we conduct experiments as directed by the simulations to achieve such morphologies in the PTB7 + PTB7- b-PNDI + PCBM model blend. We characterize the results of our experiments via a combination of transmission electron microscopy and X-ray scattering techniques and demonstrate that the morphologies from experiments agree with those predicted in simulations. Accordingly, these results indicate that the approach utilized represents a promising approach to intelligently design the morphologies taken on by organic solar cell active layers.

  3. Solar activity and terrestrial climate: an analysis of some purported correlations

    NASA Astrophysics Data System (ADS)

    Laut, Peter

    2003-05-01

    The last decade has seen a revival of various hypotheses claiming a strong correlation between solar activity and a number of terrestrial climate parameters: Links between cosmic rays and cloud cover, first total cloud cover and then only low clouds, and between solar cycle lengths and Northern Hemisphere land temperatures. These hypotheses play an important role in the scientific as well as in the public debate about the possibility or reality of a man-made global climate change. I have analyzed a number of published graphs which have played a major role in these debates and which have been claimed to support solar hypotheses. My analyses show that the apparent strong correlations displayed on these graphs have been obtained by an incorrect handling of the physical data. Since the graphs are still widely referred to in the literature and their misleading character has not yet been generally recognized, I have found it appropriate to deliver the present overview. Especially, I want to caution against drawing any conclusions based upon these graphs concerning the possible wisdom or futility of reducing the emissions of man-made greenhouse gases. My findings do not by any means rule out the existence of important links between solar activity and terrestrial climate. Such links have over the years been demonstrated by many authors. The sole objective of the present analysis is to draw attention to the fact that some of the widely publicized, apparent correlations do not properly reflect the underlying physical data.

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

    NASA Astrophysics Data System (ADS)

    Strugarek, Antoine; Janitzek, Nils; Lee, Arrow; Löschl, Philipp; Seifert, Bernhard; Hoilijoki, Sanni; Kraaikamp, Emil; Isha Mrigakshi, Alankrita; Philippe, Thomas; Spina, Sheila; Bröse, Malte; Massahi, Sonny; O'Halloran, Liam; Pereira Blanco, Victor; Stausland, Christoffer; Escoubet, Philippe; Kargl, Günter

    2015-02-01

    Coronal Mass Ejections (CMEs) and Corotating Interaction Regions (CIRs) are major sources of magnetic storms on Earth and are therefore considered to be the most dangerous space weather events. The Observatories of Solar Corona and Active Regions (OSCAR) mission is designed to identify the 3D structure of coronal loops and to study the trigger mechanisms of CMEs in solar Active Regions (ARs) as well as their evolution and propagation processes in the inner heliosphere. It also aims to provide monitoring and forecasting of geo-effective CMEs and CIRs. OSCAR would contribute to significant advancements in the field of solar physics, improvements of the current CME prediction models, and provide data for reliable space weather forecasting. These objectives are achieved by utilising two spacecraft with identical instrumentation, located at a heliocentric orbital distance of 1 AU from the Sun. The spacecraft will be separated by an angle of 68° to provide optimum stereoscopic view of the solar corona. We study the feasibility of such a mission and propose a preliminary design for OSCAR.

  5. CORONAL MAGNETOGRAPHY OF A SIMULATED SOLAR ACTIVE REGION FROM MICROWAVE IMAGING SPECTROPOLARIMETRY

    SciTech Connect

    Wang, Zhitao; Gary, Dale E.; Fleishman, Gregory D.; White, Stephen M.

    2015-06-01

    We have simulated the Expanded Owens Valley Solar Array (EOVSA) radio images generated at multiple frequencies from a model solar active region, embedded in a realistic solar disk model, and explored the resulting data cube for different spectral analysis schemes to evaluate the potential for realizing one of EOVSA’s most important scientific goals—coronal magnetography. In this paper, we focus on modeling the gyroresonance and free–free emission from an on-disk solar active region model with realistic complexities in electron density, temperature and magnetic field distribution. We compare the magnetic field parameters extrapolated from the image data cube along each line of sight after folding through the EOVSA instrumental profile with the original (unfolded) parameters used in the model. We find that even the most easily automated, image-based analysis approach (Level-0) provides reasonable quantitative results, although they are affected by systematic effects due to finite sampling in the Fourier (UV) plane. Finally, we note the potential for errors due to misidentified harmonics of the gyrofrequency, and discuss the prospects for applying a more sophisticated spectrally based analysis scheme (Level-1) to resolve the issue in cases where improved UV coverage and spatial resolution are available.

  6. Multiday thermospheric density oscillations associated with variations in solar radiation and geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Xu, Jiyao; Wang, Wenbin; Zhang, Shunrong; Liu, Xiao; Yuan, Wei

    2015-05-01

    Thermospheric densities observed by Challenging Minisatellite Payload and Gravity Recovery and Climate Experiment satellites during 2002-2010 and the globally averaged thermospheric densities from 1967 to 2007 have been used to investigate latitudinal, longitudinal, and height dependences of the multiday oscillations of thermospheric densities. The data show that the main multiday oscillations in thermospheric densities are 27, 13.5, 9, and 7 day oscillations. The high-correlation coefficients between the density oscillations and the F10.7 or Ap index indicate that these oscillations are externally driven. The 27 day density oscillation, being the strongest, is induced by variations in solar radiation, as well as recurrent geomagnetic activity that is the result of corotating interaction regions (CIRs) and high-speed solar wind streams of coronal hole origin. Density oscillations at periods of 13.5, 9, and 7 days at solar minimum and during the declining phase are stronger than those at solar maximum. These oscillations are mainly associated with recurrent geomagnetic activity due to coronal hole high-speed streams and CIRs. The multiday, periodic oscillations of thermospheric density exhibit strong latitudinal and longitudinal variations in the geomagnetic coordinate and oscillate synchronously at different heights. Oscillations with zonal wave number 0 oscillate globally, whereas those with nonzero wave numbers are strong at high geomagnetic latitudes, and hemispherically asymmetric. They are stronger in the Southern Hemisphere. The spectral distributions of thermospheric densities at different heights have almost the same latitude and longitude structures, but the spectral magnitudes increase with height.

  7. The periodicities of Solar Magnetic Activity with the Wavelet Coherence Method

    NASA Astrophysics Data System (ADS)

    Velasco Herrera, Victor Manuel

    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 (10 Be and 14 C) 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 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 have 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, quasi-triennial, quasi-quinquennial, Shawabe-cycle, Gale-cycle 60, 120 and 240 years.

  8. Short- and mid-term oscillations of solar, geomagnetic activity and cosmic-ray intensity during the last two solar magnetic cycles

    NASA Astrophysics Data System (ADS)

    Singh, Y. P.; Badruddin

    2017-04-01

    Short-and mid-term oscillations of the solar activity (sunspot number and 10.7 cm solar flux), geomagnetic activity (Ap index) and cosmic-ray intensity (neutron monitor count rate) are analysed during the past two solar-magnetic cycles (1968-1989 and 1989-2014). We have implemented the wavelet analysis on the daily time resolution data of sunspot number (SSN), 10.7 cm solar flux, geomagnetic Ap index and Oulu neutron monitor count rate. Results suggest that few quasi and intermittent oscillations are observed with remarkable power density in addition to fundamental periods, like 27 day (synodic period), 154 day (Rieger period), semi-annual, annual, 1.3 year, and 1.7 year. We have consistently observed first (27 day), second (13.5 day) and third (9.0 day) solar-rotation harmonics in the geomagnetic Ap-index during both the magnetic cycles. Rieger period is more pronounced in SSN and solar flux during 1980-82 and 1990-92. Semi-annual variation of Ap-index is consistently observed during both the magnetic cycles. The annual and 1.85 year variation are also observed in all the considered parameters with good signatures in CRI.

  9. OBSERVING EVOLUTION IN THE SUPERGRANULAR NETWORK LENGTH SCALE DURING PERIODS OF LOW SOLAR ACTIVITY

    SciTech Connect

    McIntosh, Scott W.; Rast, Mark P.; Leamon, Robert J.; Hock, Rachel A.; Ulrich, Roger K.

    2011-03-20

    We present the initial results of an observational study into the variation of the dominant length scale of quiet solar emission: supergranulation. The distribution of magnetic elements in the lanes that from the network affects, and reflects, the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Suns' interior. We demonstrate that a net difference of {approx}0.5 Mm in the supergranular emission length scale occurs when comparing observation cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the data sets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length scale over multiple solar minima by analyzing a subset of the Mount Wilson Solar Observatory Ca II K image record. The observations and analysis presented provide a tantalizing look at solar activity in the absence of large-scale flux emergence, offering insight into times of 'extreme' solar minimum and general behavior such as the phasing and cross-dependence of different components of the spectral irradiance. Given that the modulation of the supergranular scale imprints itself in variations of the Suns' spectral irradiance, as well as in the mass and energy transport into the entire outer atmosphere, this preliminary investigation is an important step in understanding the impact of the quiet Sun on the heliospheric system.

  10. Observing Evolution in the Supergranular Network Length Scale During Periods of Low Solar Activity

    NASA Astrophysics Data System (ADS)

    McIntosh, Scott W.; Leamon, Robert J.; Hock, Rachel A.; Rast, Mark P.; Ulrich, Roger K.

    2011-03-01

    We present the initial results of an observational study into the variation of the dominant length scale of quiet solar emission: supergranulation. The distribution of magnetic elements in the lanes that from the network affects, and reflects, the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Suns' interior. We demonstrate that a net difference of ~0.5 Mm in the supergranular emission length scale occurs when comparing observation cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the data sets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length scale over multiple solar minima by analyzing a subset of the Mount Wilson Solar Observatory Ca II K image record. The observations and analysis presented provide a tantalizing look at solar activity in the absence of large-scale flux emergence, offering insight into times of "extreme" solar minimum and general behavior such as the phasing and cross-dependence of different components of the spectral irradiance. Given that the modulation of the supergranular scale imprints itself in variations of the Suns' spectral irradiance, as well as in the mass and energy transport into the entire outer atmosphere, this preliminary investigation is an important step in understanding the impact of the quiet Sun on the heliospheric system.

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

    SciTech Connect

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

    2011-01-20

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

  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. Dynamo-based scheme for forecasting the magnitude of solar activity cycles

    NASA Technical Reports Server (NTRS)

    Layden, A. C.; Fox, P. A.; Howard, J. M.; Sarajedini, A.; Schatten, K. H.

    1991-01-01

    This paper presents a general framework for forecasting the smoothed maximum level of solar activity in a given cycle, based on a simple understanding of the solar dynamo. This type of forecasting requires knowledge of the sun's polar magnetic field strength at the preceding activity minimum. Because direct measurements of this quantity are difficult to obtain, the quality of a number of proxy indicators already used by other authors is evaluated, which are physically related to the sun's polar field. These indicators are subjected to a rigorous statistical analysis, and the analysis technique for each indicator is specified in detail in order to simplify and systematize reanalysis for future use. It is found that several of these proxies are in fact poorly correlated or uncorrelated with solar activity, and thus are of little value for predicting activity maxima. Also presented is a scheme in which the predictions of the individual proxies are combined via an appropriately weighted mean to produce a compound prediction. The scheme is then applied to the current cycle 22, and a maximum smoothed international sunspot number of 171 + or - 26 is estimated.

  14. Variations of 14C around AD 775 and AD 1795 - due to solar activity

    NASA Astrophysics Data System (ADS)

    Neuhäuser, R.; Neuhäuser, D. L.

    2015-12-01

    The motivation for our study is the disputed cause for the strong variation of 14C around AD 775. Our method is to compare the 14C variation around AD 775 with other periods of strong variability. Our results are: (a) We see three periods, where 14C varied over 200 yr in a special way showing a certain pattern of strong secular variation: after a Grand Minimum with strongly increasing 14C, there is a series of strong short-term drop(s), rise(s), and again drop(s) within 60 yr, ending up to 200 yr after the start of the Grand Minimum. These three periods include the strong rises around BC 671, AD 775, and AD 1795. (b) We show with several solar activity proxies (radioisotopes, sunspots, and aurorae) for the AD 770s and 1790s that such intense rapid 14C increases can be explained by strong rapid decreases in solar activity and, hence, wind, so that the decrease in solar modulation potential leads to an increase in radioisotope production. (c) The strong rises around AD 775 and 1795 are due to three effects, (i) very strong activity in the previous cycles (i.e. very low 14C level), (ii) the declining phase of a very strong Schwabe cycle, and (iii) a phase of very weak activity after the strong 14C rise - very short and/or weak cycle(s) like the suddenly starting Dalton minimum. (d) Furthermore, we can show that the strong change at AD 1795 happened after a pair of two packages of four Schwabe cycles with certain hemispheric leadership (each package consists of two Gnevyshev-Ohl pairs, respectively two Hale-Babcock pairs). We show with several additional arguments that the rise around AD 775 was not that special. We conclude that such large, short-term rises in 14C (around BC 671, AD 775, and 1795) do not need to be explained by highly unlikely solar super-flares nor other rare events, but by extra-solar cosmic rays modulated due to solar activity variations.

  15. Development of solar activity in 24th cycle: scenario of 15th cycle?

    NASA Astrophysics Data System (ADS)

    Lozytsky, V.; Efimenko, V.

    2012-12-01

    For more precise definition of prognosis of 24th cycle, the peculiarities of growth of solar activity was studied in previous 23 cycles. The interest was focused on a phase of sharp increasing of activity, beginning from 20th month of cycles. The sufficiently close correlation was found between smoothed Wolf's number in the cycle maximum Wmax and increment of sunspot's number on phase of activity increasing. From this analysis follows that for 24th cycle the following parameters are expected: Wmax = 105±11, аnd time of maximum - middle 2013. If this prognosis will be come true, the 24th cycle will be similar to cycle No. 15.

  16. Static and Impulsive Models of Solar Active Regions

    NASA Technical Reports Server (NTRS)

    Patsourakos, S.; Klimchuk, James A.

    2008-01-01

    The physical modeling of active regions (ARs) and of the global coronal is receiving increasing interest lately. Recent attempts to model ARs using static equilibrium models were quite successful in reproducing AR images of hot soft X-ray (SXR) loops. They however failed to predict the bright EUV warm loops permeating ARs: the synthetic images were dominated by intense footpoint emission. We demonstrate that this failure is due to the very weak dependence of loop temperature on loop length which cannot simultaneously account for both hot and warm loops in the same AR. We then consider time-dependent AR models based on nanoflare heating. We demonstrate that such models can simultaneously reproduce EUV and SXR loops in ARs. Moreover, they predict radial intensity variations consistent with the localized core and extended emissions in SXR and EUV AR observations respectively. We finally show how the AR morphology can be used as a gauge of the properties (duration, energy, spatial dependence, repetition time) of the impulsive heating.

  17. Solar Dynamics Observatory Discovers Thin High Temperature Strands in Coronal Active Regions

    NASA Astrophysics Data System (ADS)

    Reale, Fabio; Guarrasi, Massimiliano; Testa, Paola; DeLuca, Edward E.; Peres, Giovanni; Golub, Leon

    2011-07-01

    One scenario proposed to explain the million degree solar corona is a finely stranded corona where each strand is heated by a rapid pulse. However, such fine structure has neither been resolved through direct imaging observations nor conclusively shown through indirect observations of extended superhot plasma. Recently, it has been shown that the observed difference in the appearance of cool and warm coronal loops (~1 MK and ~2-3 MK, respectively)—warm loops appearing "fuzzier" than cool loops—can be explained by models of loops composed of subarcsecond strands, which are impulsively heated up to ~10 MK. That work predicts that images of hot coronal loops (gsim 6 MK) should again show fine structure. Here we show that the predicted effect is indeed widely observed in an active region with the Solar Dynamics Observatory, thus supporting a scenario where impulsive heating of fine loop strands plays an important role in powering the active corona.

  18. Explorations of electric current system in solar active regions. I - Empirical inferences of the current flows

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    Techniques to identify sources of electric current systems and their channels of flow in solar active regions are explored. Measured photospheric vector magnetic fields together with high-resolution white-light and H-alpha filtergrams provide the data base to derive the current systems in the photosphere and chromosphere. As an example, the techniques are then applied to infer current systems in AR 2372 in early April 1980.

  19. Effects of long-period solar activity fluctuation on temperature and pressure of the terrestrial atmosphere

    NASA Technical Reports Server (NTRS)

    Rubashev, B. M.

    1978-01-01

    The present state of research on the influence of solar sunspot activity on tropospheric temperature and pressure is reviewed. The existence of an 11-year temperature cycle of 5 different types is affirmed. A cyclic change in atmospheric pressure, deducing characteristic changes between 11-year cycles is discussed. The existence of 80-year and 5-to-6-year cycles of temperature is established, and physical causes for birth are suggested.

  20. The problem of the periodicity of the epidemic process. [solar activity effects on diphtheria outbreak

    NASA Technical Reports Server (NTRS)

    Yagodinskiy, V. N.; Konovalenko, Z. P.; Druzhinin, I. P.

    1974-01-01

    An analysis of data from epidemics makes it possible to determine their principal causes, governed by environmental factors (solar activity, etc.) The results of an analysis of the periodicity of the epidemic process in the case of diphtheria are presented which was conducted with the aid of autocorrelation and spectral methods of analysis. Numerical data (annual figures) are used on the dynamics of diphtheria in 50 regions (points) with a total duration of 2,777 years.

  1. Solar magnetic activity cycles, coronal potential field models and eruption rates

    NASA Astrophysics Data System (ADS)

    Petrie, Gordon

    2013-07-01

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the NSO's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun (SOLIS) vector spectro-magnetograph (VSM), the spectro-magnetograph and the 512-channel magnetograph instruments, and from the U. Stanford's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking (CACTus), Solar Eruptive Event Detection System (SEEDS), and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003-2012 than for those between 1997-2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  2. Low-degree p-mode parameters evolution with solar activity

    NASA Astrophysics Data System (ADS)

    Lochard, J.; Boumier, P.

    We present updated results on the low-degree p-mode parameters changes with solar activity: frequency, spectral width, rotational splittings and spectral asymmetry. A particular attention is devoted to the l=2 splitting asymmetry. Comparaisons of our frequency shifts (derived from the GOLF observations) with predictions of Pr.Dziembowski (based on an extrapolation from intermediate degree modes observations from MDI), are discussed.

  3. Forecasting the Solar Drivers of Severe Space Weather from Active-Region Magnetograms

    NASA Technical Reports Server (NTRS)

    Falconer, David A.; Moore, Ronald L.; Barghouty, Abdulnasser F.; Khazanov, Igor

    2012-01-01

    Solar drivers of severe space weather can be predicted from line-of-sight magnetograms, via a free-energy proxy measured from the neutral lines. This can be done in near real time. In addition to depending strongly on the free magnetic energy, an active region's chance of having a major eruption depends strongly on other aspects of the evolving magnetic field (e.g., its complexity and flux emergence).

  4. Evidence of Energy Supply by Active-Region Spicules to the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Zeighami, S.; Ahangarzadeh Maralani, A. R.; Tavabi, E.; Ajabshirizadeh, A.

    2016-03-01

    We investigate the role of active-region spicules in the mass balance of the solar wind and energy supply in heating the solar atmosphere. We use high-cadence observations from the Solar Optical Telescope (SOT) onboard the Hinode satellite in the Ca ii H-line filter obtained on 26 January 2007. The observational technique provides the high spatio-temporal resolution required to detect fine structures such as spicules. We apply a Fourier power spectrum and wavelet analysis to Hinode/SOT time series of an active-region data set to explore the existence of coherent intensity oscillations. Coherent waves could be evidence of energy transport that serves to heat the solar atmosphere. Using time series, we measure the phase difference between two intensity profiles obtained at two different heights, which gives information about the phase difference between oscillations at those heights as a function of frequency. The results of a fast Fourier transform (FFT) show peaks in the power spectrum at frequencies in the range from 2 to 8 mHz at four different heights (above the limb), while the wavelet analysis indicates dominant frequencies similar to those of the Fourier power spectrum results. A coherency study indicates coherent oscillations at about 5.5 mHz (3 min). We measure mean phase speeds in the range 250-425 km s^{-1} increasing with height. The energy flux of these waves is estimated to be F = 1.8 × 106-11.2 × 106 erg cm^{-2} s^{-1} or 1.8-11.2 kW m^{-2}, which indicates that they are sufficiently energetic to accelerate the solar wind and heat the corona to temperatures of several million degrees. We compute the the mass flux carried by spicules of 3 × 10^{-10}-2 × 10^{-9} g cm^{-2} s^{-1}, which is 10-60 times higher than the mass that is carried away from the corona because of the solar wind (about 3 × 10^{-11} g cm^{-2} s^{-1}). Therefore, our results indicate that about 0.02-0.1 of the spicule mass is ejected from the corona, while the remainder reverts

  5. Out-of-ecliptic studies of coronal holes and their relation to the solar wind. [project planning for solar probes to study solar activity

    NASA Technical Reports Server (NTRS)

    Noyes, R. W.

    1976-01-01

    The advantages of observing coronal holes of the sun above the solar ecliptic plane by a solar probe are discussed. Also discussed are the size of coronal holes, their temperature, and magnetic fields associated with the holes. The role of coronal holes in contributing to the solar wind is examined. Data and observations on coronal holes from Skylab and OSO are treated. It is concluded that an out-of-the-ecliptic solar probe mission would greatly add to the understanding of coronal holes (at high latitudes) thus adding a new perspective to the observation of these phenomena. (Photographs of the sun taken by Skylab are shown).

  6. Is there long-range memory in solar activity on timescales shorter than the sunspot period?

    NASA Astrophysics Data System (ADS)

    Rypdal, M.; Rypdal, K.

    2012-04-01

    The sunspot number (SSN), the total solar irradiance (TSI), a TSI reconstruction, and the solar flare index (SFI) are analyzed for long-range persistence (LRP). Standard Hurst analysis yields H ≈ 0.9, which suggests strong LRP. However, solar activity time series are nonstationary because of the almost-periodic 11 year smooth component, and the analysis does not give the correct H for the stochastic component. Better estimates are obtained by detrended fluctuation analysis, but estimates are biased and errors are large because of the short time records. These time series can be modeled as a stochastic process of the form x(t) = y(t) + σy(t)wH(t), where y(t) is the smooth component and wH(t) is a stationary fractional noise with Hurst exponent H. From ensembles of numerical solutions to the stochastic model and application of Bayes' theorem, we can obtain bias and error bars on H and also a test of the hypothesis that a process is uncorrelated (H = 1/2). The conclusions from the present data sets are that SSN, TSI, and TSI reconstruction almost certainly are long-range persistent, but with the most probable value H ≈ 0.7. The SFI process, however, is either very weakly persistent (H < 0.6) or completely uncorrelated on timescales longer than a few solar rotations. Differences between stochastic properties of the TSI and its reconstruction indicate some error in the reconstruction scheme.

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

  8. Solar irradiance observed at Summit, Greenland: Possible links to magnetic activity on short timescales

    NASA Astrophysics Data System (ADS)

    Frederick, John E.

    2016-09-01

    Measurements of ground-level visible sunlight (400-600 nm) from Summit, Greenland over the period August 2004 through October 2014 define the attenuation provided by cloudiness, including its dependence on solar elevation and season. The long-term mean cloud-attenuation increases with increasing solar zenith angle, consistent with radiative transfer calculations which treat a cloud as a plane parallel layer with a strong bias toward forward scattering and an albedo for diffuse radiation near 0.1. The ratio of measured irradiance to clear-sky irradiance for solar zenith angles greater than 66° has a small, but statistically significant, positive correlation with the previous day's magnetic activity as measured by the daily Ap index, but no clear relationship exists between the irradiance ratio and daily changes in the ground-level neutron flux measured at Thule over the time frame considered. A high value of Ap on one day tends to be followed by a day whose ground-level solar irradiance is slightly greater than would occur otherwise. In an average sense, the visible irradiance following a day with Ap>16 exceeds that following a day with Ap≤16 by 1.2-1.3% with a 95% confidence range of approximately ±1.0%. The results are broadly compatible with small changes in atmospheric scattering following magnetic disturbances.

  9. Variability of solar/stellar activity and magnetic field and its influence on planetary atmosphere evolution

    NASA Astrophysics Data System (ADS)

    Lammer, Helmut; Güdel, Manuel; Kulikov, Yuri; Ribas, Ignasi; Zaqarashvili, Teimuraz V.; Khodachenko, Maxim L.; Kislyakova, Kristina G.; Gröller, Hannes; Odert, Petra; Leitzinger, Martin; Fichtinger, Bibiana; Krauss, Sandro; Hausleitner, Walter; Holmström, Mats; Sanz-Forcada, Jorge; Lichtenegger, Herbert I. M.; Hanslmeier, Arnold; Shematovich, Valery I.; Bisikalo, Dmitry; Rauer, Heike; Fridlund, Malcolm

    2012-02-01

    It is shown that the evolution of planetary atmospheres can only be understood if one recognizes the fact that the radiation and particle environment of the Sun or a planet's host star were not always on the same level as at present. New insights and the latest observations and research regarding the evolution of the solar radiation, plasma environment and solar/stellar magnetic field derived from the observations of solar proxies with different ages will be given. We show that the extreme radiation and plasma environments of the young Sun/stars have important implications for the evolution of planetary atmospheres and may be responsible for the fact that planets with low gravity like early Mars most likely never build up a dense atmosphere during the first few 100 Myr after their origin. Finally we present an innovative new idea on how hydrogen clouds and energetic neutral atom (ENA) observations around transiting Earth-like exoplanets by space observatories such as the WSO-UV, can be used for validating the addressed atmospheric evolution studies. Such observations would enhance our understanding on the impact on the activity of the young Sun on the early atmospheres of Venus, Earth, Mars and other Solar System bodies as well as exoplanets.

  10. Magnetic Flux Transport and the Long-term Evolution of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Ugarte-Urra, Ignacio; Upton, Lisa; Warren, Harry P.; Hathaway, David H.

    2015-12-01

    With multiple vantage points around the Sun, Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory imaging observations provide a unique opportunity to view the solar surface continuously. We use He ii 304 Å data from these observatories to isolate and track ten active regions and study their long-term evolution. We find that active regions typically follow a standard pattern of emergence over several days followed by a slower decay that is proportional in time to the peak intensity in the region. Since STEREO does not make direct observations of the magnetic field, we employ a flux-luminosity relationship to infer the total unsigned magnetic flux evolution. To investigate this magnetic flux decay over several rotations we use a surface flux transport model, the Advective Flux Transport model, that simulates convective flows using a time-varying velocity field and find that the model provides realistic predictions when information about the active region's magnetic field strength and distribution at peak flux is available. Finally, we illustrate how 304 Å images can be used as a proxy for magnetic flux measurements when magnetic field data is not accessible.

  11. NEW VACUUM SOLAR TELESCOPE OBSERVATIONS OF A FLUX ROPE TRACKED BY A FILAMENT ACTIVATION

    SciTech Connect

    Yang, Shuhong; Zhang, Jun; Liu, Zhong; Xiang, Yongyuan E-mail: zjun@nao.cas.cn

    2014-04-01

    One main goal of the New Vacuum Solar Telescope (NVST) which is located at the Fuxian Solar Observatory is to image the Sun at high resolution. Based on the high spatial and temporal resolution NVST Hα data and combined with the simultaneous observations from the Solar Dynamics Observatory for the first time, we investigate a flux rope tracked by filament activation. The filament material is initially located at one end of the flux rope and fills in a section of the rope; the filament is then activated by magnetic field cancellation. The activated filament rises and flows along helical threads, tracking the twisted flux rope structure. The length of the flux rope is about 75 Mm, the average width of its individual threads is 1.11 Mm, and the estimated twist is 1π. The flux rope appears as a dark structure in Hα images, a partial dark and partial bright structure in 304 Å, and as a bright structure in 171 Å and 131 Å images. During this process, the overlying coronal loops are quite steady since the filament is confined within the flux rope and does not erupt successfully. It seems that, for the event in this study, the filament is located and confined within the flux rope threads, instead of being suspended in the dips of twisted magnetic flux.

  12. Solar and geomagnetic activity effects on nocturnal zonal velocities of ionospheric plasma depletions.

    NASA Astrophysics Data System (ADS)

    Sobral, J. H. A.; Abdu, M. A.; Takahashi, H.; Sawant, H.; Zamlutti, C. J.; Borba, G. L.

    1999-01-01

    The understanding of postsunset zonal drifts of ionospheric plasma depletions in the equatorial and subequatorial regions are of importance to the knowledge of the electrodynamics of the nocturnal ionosphere. Drifts occurring over the low latitude station Cachoeira Paulista-CP during the October and March time frames are analyzed for the period 1980 - 1992. That analysis is based upon about 650 days of zonal scanning photometer measurements of the nocturnal O I 630 nm airglow. The zonal motions of valleys of the O I 630 nm intensity are used to infer the eastward plasma velocity variations with local time. In this way, the velocity variations with solar activity and magnetic activity are studied. The mean trend in the velocity local time variation is a decrease from early evening to postmidnight hours, as expected in view of the F-region vertical electric fields, naturally decreasing magnitudes after sunset due to recombination. The zonal velocity decay between 21 LT and 02 LT is faster during the period of maximum solar activity than during the solar minimum period.

  13. Analyzing the validity of a possible relation between solar-terrestrial magnetic activity and earthquakes

    NASA Astrophysics Data System (ADS)

    Tapia, M. J.; Dominguez, M.; Pinto, V. A.; Moya, P. S.; Munoz, V.; Rogan, J.; Valdivia, J. A.

    2013-12-01

    A connection between solar-terrestrial geomagnetic activity and seismicity has been long proposed. Some studies claim there are global effects, relating solar activity, for instance sunspot number or solar wind speed, with earthquakes occurrence on the Earth. Other studies intend to find effects on a local scale, where perturbations in the geomagnetic activity are followed by seismic events. To address these issues, we analyze the statistical validity of some of the reported correlations, by means of two statistical approaches in both scales, namely the use of surrogate and Student's test. Regarding to the global analysis, we study the correlations between the sunspots area, Dst index, and the total annual released seismic energy during the last century. For local geomagnetic variations prior to an important earthquake, we carry out a similar statistical analysis between magnetic field fluctuations from the SAMBA array and the Dst index in a window of two years centered in the February 27th, 2010 M = 8.8 earthquake at Chile.

  14. MAGNETIC FLUX TRANSPORT AND THE LONG-TERM EVOLUTION OF SOLAR ACTIVE REGIONS

    SciTech Connect

    Ugarte-Urra, Ignacio; Upton, Lisa; Warren, Harry P.; Hathaway, David H.

    2015-12-20

    With multiple vantage points around the Sun, Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory imaging observations provide a unique opportunity to view the solar surface continuously. We use He ii 304 Å data from these observatories to isolate and track ten active regions and study their long-term evolution. We find that active regions typically follow a standard pattern of emergence over several days followed by a slower decay that is proportional in time to the peak intensity in the region. Since STEREO does not make direct observations of the magnetic field, we employ a flux-luminosity relationship to infer the total unsigned magnetic flux evolution. To investigate this magnetic flux decay over several rotations we use a surface flux transport model, the Advective Flux Transport model, that simulates convective flows using a time-varying velocity field and find that the model provides realistic predictions when information about the active region's magnetic field strength and distribution at peak flux is available. Finally, we illustrate how 304 Å images can be used as a proxy for magnetic flux measurements when magnetic field data is not accessible.

  15. Differences of the Solar Magnetic Activity Signature in Velocity and Intensity Helioseismic Observations

    NASA Astrophysics Data System (ADS)

    Salabert, D.; García, R. A.; Jiménez, A.

    2013-12-01

    The high-quality, full-disk helioseismic observations continuously collected by the spectrophotometer GOLF and the three photometers VIRGO/SPMs onboard the SoHO spacecraft for 17 years now (since April 11, 1996, apart from the SoHO “vacations”) are absolutely unique for the study of the interior of the Sun and its variability with magnetic activity. Here, we look at the differences in the low-degree oscillation p-mode frequencies between radial velocity and intensity measurements taking into account all the known features of the p-mode profiles (e.g., the opposite peak asymmetry), and of the power spectrum (e.g., the presence of the higher degrees ℓ = 4 and 5 in the signal). We show that the intensity frequencies are higher than the velocity frequencies during the solar cycle with a clear temporal dependence. The response between the individual angular degrees is also different. Time delays are observed between the temporal variations in GOLF and VIRGO frequencies. Such analysis is important in order to put new constraints and to better understand the mechanisms responsible for the temporal variations of the oscillation frequencies with the solar magnetic activity as well as their height dependences in the solar atmosphere. It is also important for the study of the stellar magnetic activity using asteroseismic data.

  16. A Method for Measuring Active Region Filling Factors on Solar-Type Stars

    NASA Astrophysics Data System (ADS)

    Giampapa, Mark Steven; Andretta, Vincenzo; Beeck, Benjamin; Reiners, Ansgar; Schussler, Manfred

    2015-04-01

    Radiative diagnostics of “activity” in the Sun and solar-type stars are spatially associated with sites of emergent magnetic flux. The magnetic fields themselves are widely regarded as the surface manifestations of a dynamo mechanism. The further development of both dynamo theory and models of the non-radiative heating of outer stellar atmospheres requires a knowledge of stellar magnetic field properties. In this context, it becomes important to determine the surface distribution, or at least the fractional coverage of, magnetic active regions as one critical constraint for dynamo models. But, while information on the spatial distribution of activity on stellar surfaces can be gathered in some special cases (mostly rapid rotators), such measurements have always been elusive in more solar-like stars. We discuss the challenges and results obtained from a method that relies on the non-linear response of the two principal He I triplet lines (at 1083 nm and 587.6 nm) to infer useful constraints on the fractional area coverage of magnetic active regions on solar-type stars.

  17. MAGNETIC NONPOTENTIALITY IN PHOTOSPHERIC ACTIVE REGIONS AS A PREDICTOR OF SOLAR FLARES

    SciTech Connect

    Yang Xiao; Lin Ganghua; Zhang Hongqi; Mao Xinjie

    2013-09-10

    Based on several magnetic nonpotentiality parameters obtained from the vector photospheric active region magnetograms obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station over two solar cycles, a machine learning model has been constructed to predict the occurrence of flares in the corresponding active region within a certain time window. The Support Vector Classifier, a widely used general classifier, is applied to build and test the prediction models. Several classical verification measures are adopted to assess the quality of the predictions. We investigate different flare levels within various time windows, and thus it is possible to estimate the rough classes and erupting times of flares for particular active regions. Several combinations of predictors have been tested in the experiments. The True Skill Statistics are higher than 0.36 in 97% of cases and the Heidke Skill Scores range from 0.23 to 0.48. The predictors derived from longitudinal magnetic fields do perform well, however, they are less sensitive in predicting large flares. Employing the nonpotentiality predictors from vector fields improves the performance of predicting large flares of magnitude {>=}M5.0 and {>=}X1.0.

  18. Physical Model of Solar Activity Influence on Climate Characteristics of Troposphere.

    NASA Astrophysics Data System (ADS)

    Molodykh, S. I.; Zherebtsov, G. A.; Kovalenko, V. A.

    2009-10-01

    A new model of solar activity influence on the parameters of the terrestrial climate system is discussed. The main points of the model of solar activity effect on the terrestrial climate system are presented. The key conception of this model is the influence of heliogeophysical disturbances on the terrestrial climate system parameters controlling the energy flux going from the Earth to the space in polar regions. The model is based on the physical mechanism of the influence of heliogeophysical factors on climate characteristics and atmospheric circulation in high-latitude troposphere through atmospheric electricity. According to this model, the growth of solar activity results in the decrease of radiative cooling in high-latitude regions, increase of temperature of lower and middle troposphere, reorganization of the thermobaric field, decrease of the mean meridional gradient of temperature between polar and equatorial regions, which determine the meridional transportation of heat. The decrease of heat flow-out from low-latitude regions results in temperature increase in lower and middle latitude regions, and increase of heat content of the ocean and climate system. Some observational data are presented that confirm the proposed model.

  19. A Combined Analysis of the Observational Aspects of the Quasi-biennial Oscillation in Solar Magnetic Activity

    NASA Astrophysics Data System (ADS)

    Bazilevskaya, G.; Broomhall, A.-M.; Elsworth, Y.; Nakariakov, V. M.

    2014-12-01

    Solar quasi-biennial oscillations (QBOs) with the time scale of 0.6-4 yrs appear to be a basic feature of the Sun's activity. Observational aspects of QBOs are reviewed on the basis of recent publications. Solar QBOs are shown to be ubiquitous and very variable. We demonstrate that many features of QBOs are common to different observations. These features include variable periodicity and intermittence with signs of stochastisity, a presence at all levels of the solar atmosphere and even in the convective zone, independent development in the northern and southern solar hemispheres, most pronounced amplitudes during the maximum phase of the 11-yr cycle and the transition of QBOs into interplanetary space. Temporal weakening of solar activity around the maximum of the 11-yr cycle (Gnevyshev Gap) can be considered an integral part of QBOs. The exact mechanism by which the solar QBO is produced is poorly understood. We describe some of the most plausible theoretical mechanisms and discuss observational features that support/contradict the theory. QBOs have an important meaning as a benchmark of solar activity, not only for investigation of the solar dynamo but also in terms of space weather.

  20. Solar Energy and You.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    This booklet provides an introduction to solar energy by discussing: (1) how a home is heated; (2) how solar energy can help in the heating process; (3) the characteristics of passive solar houses; (4) the characteristics of active solar houses; (5) how solar heat is stored; and (6) other uses of solar energy. Also provided are 10 questions to…