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.

Jupiter's outer atmosphere.

NASA Technical Reports Server (NTRS)

Brice, N. M.

1973-01-01

The current state of the theory of Jupiter's outer atmosphere is briefly reviewed. The similarities and dissimilarities between the terrestrial and Jovian upper atmospheres are discussed, including the interaction of the solar wind with the planetary magnetic fields. Estimates of Jovian parameters are given, including magnetosphere and auroral zone sizes, ionospheric conductivity, energy inputs, and solar wind parameters at Jupiter. The influence of the large centrifugal force on the cold plasma distribution is considered. The Jovian Van Allen belt is attributed to solar wind particles diffused in toward the planet by dynamo electric fields from ionospheric neutral winds, and the consequences of this theory are indicated.

Wave Modeling of the Solar Wind.

PubMed

Ofman, Leon

The acceleration and heating of the solar wind have been studied for decades using satellite observations and models. However, the exact mechanism that leads to solar wind heating and acceleration is poorly understood. In order to improve the understanding of the physical mechanisms that are involved in these processes a combination of modeling and observational analysis is required. Recent models constrained by satellite observations show that wave heating in the low-frequency (MHD), and high-frequency (ion-cyclotron) range may provide the necessary momentum and heat input to coronal plasma and produce the solar wind. This review is focused on the results of several recent solar modeling studies that include waves explicitly in the MHD and the kinetic regime. The current status of the understanding of the solar wind acceleration and heating by waves is reviewed.

Solar wind structure suggested by bimodal correlations of solar wind speed and density between the spacecraft SOHO and Wind

NASA Astrophysics Data System (ADS)

Ogilvie, K. W.; Coplan, M. A.; Roberts, D. A.; Ipavich, F.

2007-08-01

We calculate the cross-spacecraft maximum lagged-cross-correlation coefficients for 2-hour intervals of solar wind speed and density measurements made by the plasma instruments on the Solar and Heliospheric Observatory (SOHO) and Wind spacecraft over the period from 1996, the minimum of solar cycle 23, through the end of 2005. During this period, SOHO was located at L1, about 200 R E upstream from the Earth, while Wind spent most of the time in the interplanetary medium at distances of more than 100 R E from the Earth. Yearly histograms of the maximum, time-lagged correlation coefficients for both the speed and density are bimodal in shape, suggesting the existence of two distinct solar wind regimes. The larger correlation coefficients we suggest are due to structured solar wind, including discontinuities and shocks, while the smaller are likely due to Alfvénic turbulence. While further work will be required to firmly establish the physical nature of the two populations, the results of the analysis are consistent with a solar wind that consists of turbulence from quiet regions of the Sun interspersed with highly filamentary structures largely convected from regions in the inner solar corona. The bimodal appearance of the distributions is less evident in the solar wind speed than in the density correlations, consistent with the observation that the filamentary structures are convected with nearly constant speed by the time they reach 1 AU. We also find that at solar minimum the fits for the density correlations have smaller high-correlation components than at solar maximum. We interpret this as due to the presence of more relatively uniform Alfvénic regions at solar minimum than at solar maximum.

A Deeper Understanding of Stability in the Solar Wind: Applying Nyquist's Instability Criterion to Wind Faraday Cup Data

NASA Astrophysics Data System (ADS)

Alterman, B. L.; Klein, K. G.; Verscharen, D.; Stevens, M. L.; Kasper, J. C.

2017-12-01

Long duration, in situ data sets enable large-scale statistical analysis of free-energy-driven instabilities in the solar wind. The plasma beta and temperature anisotropy plane provides a well-defined parameter space in which a single-fluid plasma's stability can be represented. Because this reduced parameter space can only represent instability thresholds due to the free energy of one ion species - typically the bulk protons - the true impact of instabilities on the solar wind is under estimated. Nyquist's instability criterion allows us to systematically account for other sources of free energy including beams, drifts, and additional temperature anisotropies. Utilizing over 20 years of Wind Faraday cup and magnetic field observations, we have resolved the bulk parameters for three ion populations: the bulk protons, beam protons, and alpha particles. Applying Nyquist's criterion, we calculate the number of linearly growing modes supported by each spectrum and provide a more nuanced consideration of solar wind stability. Using collisional age measurements, we predict the stability of the solar wind close to the sun. Accounting for the free-energy from the three most common ion populations in the solar wind, our approach provides a more complete characterization of solar wind stability.

Comparison of the Effects of Wave-Particle Interactions and the Kinetic Suprathermal Electron Population on the Acceleration of the Solar Wind

NASA Technical Reports Server (NTRS)

Tam, S. W. Y.; Chang, T.

2002-01-01

Kinetic effects due to wave-particle interactions and suprathermal electrons have been suggested in the literature as possible solar wind acceleration mechanisms. Ion cyclotron resonant heating, in particular, has been associated with some qualitative features observed in the solar wind. In terms of solar wind acceleration, however, it is interesting to compare the kinetic effects of suprathermal electrons with those due to the wave-particle interactions. The combined effects of the two acceleration mechanisms on the fast solar wind have been studied by Tam and Chang (1999a,b). In this study. we investigate the role of the suprathermal electron population in the acceleration of the solar wind. Our model follows the global kinetic evolution of the fast solar wind under the influence of ion cyclotron resonant heating, while taking into account Coulomb collisions, and the ambipolar electric field that is consistent with the particle distributions themselves. The kinetic effects due to the suprathermal electrons, which we define to be the tail of the electron distributions, can be included in the model as an option. By comparing the results with and without the inclusion of the suprathermal electron effects, we determine the relative importance of suprathermal electrons and wave-particle interactions in driving the solar wind. We find that although suprathermal electrons enhance the ambipolar electric potential in the solar wind considerably, their overall influence as an acceleration mechanism is relatively insignificant in a wave-driven solar wind.

Computational techniques for solar wind flows past terrestrial planets: Theory and computer programs

NASA Technical Reports Server (NTRS)

Stahara, S. S.; Chaussee, D. S.; Trudinger, B. C.; Spreiter, J. R.

1977-01-01

The interaction of the solar wind with terrestrial planets can be predicted using a computer program based on a single fluid, steady, dissipationless, magnetohydrodynamic model to calculate the axisymmetric, supersonic, super-Alfvenic solar wind flow past both magnetic and nonmagnetic planets. The actual calculations are implemented by an assemblage of computer codes organized into one program. These include finite difference codes which determine the gas-dynamic solution, together with a variety of special purpose output codes for determining and automatically plotting both flow field and magnetic field results. Comparisons are made with previous results, and results are presented for a number of solar wind flows. The computational programs developed are documented and are presented in a general user's manual which is included.

Prediction of Geomagnetic Activity and Key Parameters in High-latitude Ionosphere

NASA Technical Reports Server (NTRS)

Khazanov, George V.; Lyatsky, Wladislaw; Tan, Arjun; Ridley, Aaron

2007-01-01

Prediction of geomagnetic activity and related events in the Earth's magnetosphere and ionosphere are important tasks of US Space Weather Program. Prediction reliability is dependent on the prediction method, and elements included in the prediction scheme. Two of the main elements of such prediction scheme are: an appropriate geomagnetic activity index, and an appropriate coupling function (the combination of solar wind parameters providing the best correlation between upstream solar wind data and geomagnetic activity). We have developed a new index of geomagnetic activity, the Polar Magnetic (PM) index and an improved version of solar wind coupling function. PM index is similar to the existing polar cap PC index but it shows much better correlation with upstream solar wind/IMF data and other events in the magnetosphere and ionosphere. We investigate the correlation of PM index with upstream solar wind/IMF data for 10 years (1995-2004) that include both low and high solar activity. We also have introduced a new prediction function for the predicting of cross-polar-cap voltage and Joule heating based on using both PM index and upstream solar wind/IMF data. As we show such prediction function significantly increase the reliability of prediction of these important parameters. The correlation coefficients between the actual and predicted values of these parameters are approx. 0.9 and higher.

Hybrid Model of Inhomogeneous Solar Wind Plasma Heating by Alfven Wave Spectrum: Parametric Studies

NASA Technical Reports Server (NTRS)

Ofman, L.

2010-01-01

Observations of the solar wind plasma at 0.3 AU and beyond show that a turbulent spectrum of magnetic fluctuations is present. Remote sensing observations of the corona indicate that heavy ions are hotter than protons and their temperature is anisotropic (T(sub perpindicular / T(sub parallel) >> 1). We study the heating and the acceleration of multi-ion plasma in the solar wind by a turbulent spectrum of Alfvenic fluctuations using a 2-D hybrid numerical model. In the hybrid model the protons and heavy ions are treated kinetically as particles, while the electrons are included as neutralizing background fluid. This is the first two-dimensional hybrid parametric study of the solar wind plasma that includes an input turbulent wave spectrum guided by observation with inhomogeneous background density. We also investigate the effects of He++ ion beams in the inhomogeneous background plasma density on the heating of the solar wind plasma. The 2-D hybrid model treats parallel and oblique waves, together with cross-field inhomogeneity, self-consistently. We investigate the parametric dependence of the perpendicular heating, and the temperature anisotropy in the H+-He++ solar wind plasma. It was found that the scaling of the magnetic fluctuations power spectrum steepens in the higher-density regions, and the heating is channeled to these regions from the surrounding lower-density plasma due to wave refraction. The model parameters are applicable to the expected solar wind conditions at about 10 solar radii.

The solar cycle variation of coronal mass ejections and the solar wind mass flux

NASA Technical Reports Server (NTRS)

Webb, David F.; Howard, Russell A.

1994-01-01

Coronal mass ejections (CMEs) are an important aspect of coronal physics and a potentially significant contributor to perturbations of the solar wind, such as its mass flux. Sufficient data on CMEs are now available to permit study of their longer-term occurrency patterns. Here we present the results of a study of CME occurrence rates over more than a complete 11-year solar sunspot cycle and a comparison of these rates with those of other activity related to CMEs and with the solar wind particle flux at 1 AU. The study includes an evaluation of correlations to the CME rates, which include instrument duty cycles, visibility functions, mass detection thresholds, and geometrical considerations. The main results are as follows: (1) The frequency of occurrence of CMEs tends to track the solar activity cycle in both amplitude and phase; (2) the CME rates from different instruments, when corrected for both duty cycles and visibility functions, are reasonably consistent; (3) considering only longer-term averages, no one class of solar activity is better correlated with CME rate than any other; (4) the ratio of the annualized CME to solar wind mass flux tends to track the solar cycle; and (5) near solar maximum, CMEs can provide a significant fraction (i.e., approximately equals 15%) of the average mass flux to the near-ecliptic solar wind.

Survey of the spectral properties of turbulence in the solar wind, the magnetospheres of Venus and Earth, at solar minimum and maximum

NASA Astrophysics Data System (ADS)

Echim, Marius M.

2014-05-01

In the framework of the European FP7 project STORM ("Solar system plasma Turbulence: Observations, inteRmittency and Multifractals") we analyze the properties of turbulence in various regions of the solar system, for the minimum and respectively maximum of the solar activity. The main scientific objective of STORM is to advance the understanding of the turbulent energy transfer, intermittency and multifractals in space plasmas. Specific analysis methods are applied on magnetic field and plasma data provided by Ulysses, Venus Express and Cluster, as well as other solar system missions (e.g. Giotto, Cassini). In this paper we provide an overview of the spectral properties of turbulence derived from Power Spectral Densities (PSD) computed in the solar wind (from Ulysses, Cluster, Venus Express) and at the interface of planetary magnetospheres with the solar wind (from Venus Express, Cluster). Ulysses provides data in the solar wind between 1992 and 2008, out of the ecliptic, at radial distances ranging between 1.3 and 5.4 AU. We selected only those Ulysses data that satisfy a consolidated set of selection criteria able to identify "pure" fast and slow wind. We analyzed Venus Express data close to the orbital apogee, in the solar wind, at 0.72 AU, and in the Venus magnetosheath. We investigated Cluster data in the solar wind (for time intervals not affected by planetary ions effects), the magnetosheath and few crossings of other key magnetospheric regions (cusp, plasma sheet). We organize our PSD results in three solar wind data bases (one for the solar maximum, 1999-2001, two for the solar minimum, 1997-1998 and respectively, 2007-2008), and two planetary databases (one for the solar maximum, 2000-2001, that includes PSD obtained in the terrestrial magnetosphere, and one for the solar minimum, 2007-2008, that includes PSD obtained in the terrestrial and Venus magnetospheres and magnetosheaths). In addition to investigating the properties of turbulence for the minimum and maximum of the solar cycle we also analyze the spectral similarities and differences between fast and slow wind turbulence. We emphasize the importance of our data survey and analysis in the context of understanding the solar wind turbulence, the exploitation of data bases and as a first step towards developing a (virtual) laboratory for studying solar system plasma turbulence. Research supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 313038/STORM, and a grant of the Romanian Ministry of National Education, CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0418.

Estimates of Sputter Yields of Solar-Wind Heavy Ions of Lunar Regolith Materials

NASA Technical Reports Server (NTRS)

Barghouty, Abdulmasser F.; Adams, James H., Jr.

2008-01-01

At energies of approximately 1 keV/amu, solar-wind protons and heavy ions interact with the lunar surface materials via a number of microscopic interactions that include sputtering. Solar-wind induced sputtering is a main mechanism by which the composition of the topmost layers of the lunar surface can change, dynamically and preferentially. This work concentrates on sputtering induced by solar-wind heavy ions. Sputtering associated with slow (speeds the electrons speed in its first Bohr orbit) and highly charged ions are known to include both kinetic and potential sputtering. Potential sputtering enjoys some unique characteristics that makes it of special interest to lunar science and exploration. Unlike the yield from kinetic sputtering where simulation and approximation schemes exist, the yield from potential sputtering is not as easy to estimate. This work will present a preliminary numerical scheme designed to estimate potential sputtering yields from reactions relevant to this aspect of solar-wind lunar-surface coupling.

Scientific Analysis of Data for the ISTP/SOLARMAX Programs

NASA Technical Reports Server (NTRS)

Lazarus, Alan J.

2001-01-01

This Grant supplemented our work on data analysis from the Wind spacecraft which was one of the ISTRIA fleet of spacecraft. It was targeted at observations related to the time of solar maximum in 2000. The work we proposed to do under this grant included comparison of solar wind parameters obtained from different spacecraft in order to establish correlation lengths appropriate to the solar wind and also to compare parameters to explore solar cycle effects.

Turbulent Transport in a Three-dimensional Solar Wind

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiota, D.; Zank, G. P.; Adhikari, L.

2017-03-01

Turbulence in the solar wind can play essential roles in the heating of coronal and solar wind plasma and the acceleration of the solar wind and energetic particles. Turbulence sources are not well understood and thought to be partly enhanced by interaction with the large-scale inhomogeneity of the solar wind and the interplanetary magnetic field and/or transported from the solar corona. To investigate the interaction with background inhomogeneity and the turbulence sources, we have developed a new 3D MHD model that includes the transport and dissipation of turbulence using the theoretical model of Zank et al. We solve for themore » temporal and spatial evolution of three moments or variables, the energy in the forward and backward fluctuating modes and the residual energy and their three corresponding correlation lengths. The transport model is coupled to our 3D model of the inhomogeneous solar wind. We present results of the coupled solar wind-turbulence model assuming a simple tilted dipole magnetic configuration that mimics solar minimum conditions, together with several comparative intermediate cases. By considering eight possible solar wind and turbulence source configurations, we show that the large-scale solar wind and IMF inhomogeneity and the strength of the turbulence sources significantly affect the distribution of turbulence in the heliosphere within 6 au. We compare the predicted turbulence distribution results from a complete solar minimum model with in situ measurements made by the Helios and Ulysses spacecraft, finding that the synthetic profiles of the turbulence intensities show reasonable agreement with observations.« less

Solar wind and the motion of dust grains

NASA Astrophysics Data System (ADS)

Klačka, J.; Petržala, J.; Pástor, P.; Kómar, L.

2012-04-01

In this paper, we investigate the action of solar wind on an arbitrarily shaped interplanetary dust particle. The final relativistically covariant equation of motion of the particle also contains the change of the particle's mass. The non-radial solar wind velocity vector is also included. The covariant equation of motion reduces to the Poynting-Robertson effect in the limiting case when a spherical particle is treated, when the speed of the incident solar wind corpuscles tends to the speed of light and when the corpuscles spread radially from the Sun. The results of quantum mechanics have to be incorporated into the physical considerations, in order to obtain the limiting case. If the solar wind affects the motion of a spherical interplanetary dust particle, then ?. Here, p'in and p'out are the incoming and outgoing radiation momenta (per unit time), respectively, measured in the proper frame of reference of the particle, and ? and ? are the solar wind pressure and the total scattering cross-sections, respectively. An analytical solution of the derived equation of motion yields a qualitative behaviour consistent with numerical calculations. This also holds if we consider a decrease of the particle's mass. Using numerical integration of the derived equation of motion, we confirm our analytical result that the non-radial solar wind (with a constant value of angle between the radial direction and the direction of the solar wind velocity) causes outspiralling of the dust particle from the Sun for large values of the particle's semimajor axis. The non-radial solar wind also increases the time the particle spirals towards the Sun. If we consider the periodical variability of the solar wind with the solar cycle, then there are resonances between the particle's orbital period and the period of the solar cycle.

Statistical validation of a solar wind propagation model from 1 to 10 AU

NASA Astrophysics Data System (ADS)

Zieger, Bertalan; Hansen, Kenneth C.

2008-08-01

A one-dimensional (1-D) numerical magnetohydrodynamic (MHD) code is applied to propagate the solar wind from 1 AU through 10 AU, i.e., beyond the heliocentric distance of Saturn's orbit, in a non-rotating frame of reference. The time-varying boundary conditions at 1 AU are obtained from hourly solar wind data observed near the Earth. Although similar MHD simulations have been carried out and used by several authors, very little work has been done to validate the statistical accuracy of such solar wind predictions. In this paper, we present an extensive analysis of the prediction efficiency, using 12 selected years of solar wind data from the major heliospheric missions Pioneer, Voyager, and Ulysses. We map the numerical solution to each spacecraft in space and time, and validate the simulation, comparing the propagated solar wind parameters with in-situ observations. We do not restrict our statistical analysis to the times of spacecraft alignment, as most of the earlier case studies do. Our superposed epoch analysis suggests that the prediction efficiency is significantly higher during periods with high recurrence index of solar wind speed, typically in the late declining phase of the solar cycle. Among the solar wind variables, the solar wind speed can be predicted to the highest accuracy, with a linear correlation of 0.75 on average close to the time of opposition. We estimate the accuracy of shock arrival times to be as high as 10-15 hours within ±75 d from apparent opposition during years with high recurrence index. During solar activity maximum, there is a clear bias for the model to predicted shocks arriving later than observed in the data, suggesting that during these periods, there is an additional acceleration mechanism in the solar wind that is not included in the model.

RECONSTRUCTING THE SOLAR WIND FROM ITS EARLY HISTORY TO CURRENT EPOCH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Airapetian, Vladimir S.; Usmanov, Arcadi V., E-mail: vladimir.airapetian@nasa.gov, E-mail: avusmanov@gmail.com

Stellar winds from active solar-type stars can play a crucial role in removal of stellar angular momentum and erosion of planetary atmospheres. However, major wind properties except for mass-loss rates cannot be directly derived from observations. We employed a three-dimensional magnetohydrodynamic Alfvén wave driven solar wind model, ALF3D, to reconstruct the solar wind parameters including the mass-loss rate, terminal velocity, and wind temperature at 0.7, 2, and 4.65 Gyr. Our model treats the wind thermal electrons, protons, and pickup protons as separate fluids and incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating to properly describe proton and electronmore » temperatures of the solar wind. To study the evolution of the solar wind, we specified three input model parameters, the plasma density, Alfvén wave amplitude, and the strength of the dipole magnetic field at the wind base for each of three solar wind evolution models that are consistent with observational constrains. Our model results show that the velocity of the paleo solar wind was twice as fast, ∼50 times denser and 2 times hotter at 1 AU in the Sun's early history at 0.7 Gyr. The theoretical calculations of mass-loss rate appear to be in agreement with the empirically derived values for stars of various ages. These results can provide realistic constraints for wind dynamic pressures on magnetospheres of (exo)planets around the young Sun and other active stars, which is crucial in realistic assessment of the Joule heating of their ionospheres and corresponding effects of atmospheric erosion.« less

Molecular Substrate Alteration by Solar Wind Radiation Documented on Flown Genesis Mission Array Materials

NASA Technical Reports Server (NTRS)

Calaway, Michael J.; Stansbery, Eileen K.

2006-01-01

The Genesis spacecraft sampling arrays were exposed to various regimes of solar wind during flight that included: 313.01 days of high-speed wind from coronal holes, 335.19 days of low-speed inter-stream wind, 191.79 days of coronal mass ejections, and 852.83 days of bulk solar wind at Lagrange 1 orbit. Ellipsometry measurements taken at NASA s Johnson Space Center show that all nine flown array materials from the four Genesis regimes have been altered by solar wind exposure during flight. These measurements show significant changes in the optical constant for all nine ultra-pure materials that flew on Genesis when compared with their non-flight material standard. This change in the optical constant (n and k) of the material suggests that the molecular structure of the all nine ultra-pure materials have been altered by solar radiation. In addition, 50 samples of float-zone and czochralski silicon bulk array ellipsometry results were modeled with an effective medium approximation layer (EMA substrate layer) revealing a solar radiation molecular damage zone depth below the SiO2 native oxide layer ranging from 392 to 613 . This bulk solar wind radiation penetration depth is comparable to the depth of solar wind implantation depth of Mg measured by SIMS and SARISA.

Earth's magnetosphere and outer radiation belt under sub-Alfvénic solar wind

PubMed Central

Lugaz, Noé; Farrugia, Charles J.; Huang, Chia-Lin; Winslow, Reka M.; Spence, Harlan E.; Schwadron, Nathan A.

2016-01-01

The interaction between Earth's magnetic field and the solar wind results in the formation of a collisionless bow shock 60,000–100,000 km upstream of our planet, as long as the solar wind fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the solar wind Mach number reached steady values <1 for several hours on 17 January 2013. Simultaneous measurements by more than ten spacecraft in the near-Earth environment reveal the evanescence of the bow shock, the sunward motion of the magnetopause and the extremely rapid and intense loss of electrons in the outer radiation belt. This study allows us to directly observe the state of the inner magnetosphere, including the radiation belts during a type of solar wind-magnetosphere coupling which is unusual for planets in our solar system but may be common for close-in extrasolar planets. PMID:27694887

Earth's magnetosphere and outer radiation belt under sub-Alfvénic solar wind.

PubMed

Lugaz, Noé; Farrugia, Charles J; Huang, Chia-Lin; Winslow, Reka M; Spence, Harlan E; Schwadron, Nathan A

2016-10-03

The interaction between Earth's magnetic field and the solar wind results in the formation of a collisionless bow shock 60,000-100,000 km upstream of our planet, as long as the solar wind fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the solar wind Mach number reached steady values <1 for several hours on 17 January 2013. Simultaneous measurements by more than ten spacecraft in the near-Earth environment reveal the evanescence of the bow shock, the sunward motion of the magnetopause and the extremely rapid and intense loss of electrons in the outer radiation belt. This study allows us to directly observe the state of the inner magnetosphere, including the radiation belts during a type of solar wind-magnetosphere coupling which is unusual for planets in our solar system but may be common for close-in extrasolar planets.

Greening the Grid: Pathways to Integrate 175 Gigawatts of Renewable Energy into India’s Electric Grid, Vol. I. National Study. Executive Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palchak, David; Cochran, Jaquelin; Deshmukh, Ranjit

The use of renewable energy (RE) sources, primarily wind and solar generation, is poised to grow significantly within the Indian power system. The Government of India has established an installed capacity target of 175 gigawatts (GW) RE by 2022 that includes 60 GW of wind and 100 GW of solar, up from current capacities of 29 GW wind and 9 GW solar. India’s contribution to global efforts on climate mitigation extends this ambition to 40% non-fossil-based generation capacity by 2030. Global experience demonstrates that power systems can integrate wind and solar at this scale; however, evidence-based planning is important tomore » achieve wind and solar integration at least cost. The purpose of this analysis is to evaluate the operation of India’s power grid with 175 GW of RE in order to identify potential cost and operational concerns and actions needed to efficiently integrate this level of wind and solar generation.« less

Three-Dimensional Magnetohydrodynamic Modeling of the Solar Wind Including Pickup Protons and Turbulence Transport

NASA Technical Reports Server (NTRS)

Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.

2012-01-01

To study the effects of interstellar pickup protons and turbulence on the structure and dynamics of the solar wind, we have developed a fully three-dimensional magnetohydrodynamic solar wind model that treats interstellar pickup protons as a separate fluid and incorporates the transport of turbulence and turbulent heating. The governing system of equations combines the mean-field equations for the solar wind plasma, magnetic field, and pickup protons and the turbulence transport equations for the turbulent energy, normalized cross-helicity, and correlation length. The model equations account for photoionization of interstellar hydrogen atoms and their charge exchange with solar wind protons, energy transfer from pickup protons to solar wind protons, and plasma heating by turbulent dissipation. Separate mass and energy equations are used for the solar wind and pickup protons, though a single momentum equation is employed under the assumption that the pickup protons are comoving with the solar wind protons.We compute the global structure of the solar wind plasma, magnetic field, and turbulence in the region from 0.3 to 100 AU for a source magnetic dipole on the Sun tilted by 0 deg - .90 deg and compare our results with Voyager 2 observations. The results computed with and without pickup protons are superposed to evaluate quantitatively the deceleration and heating effects of pickup protons, the overall compression of the magnetic field in the outer heliosphere caused by deceleration, and the weakening of corotating interaction regions by the thermal pressure of pickup protons.

Analysis of Wind Forces on Roof-Top Solar Panel

NASA Astrophysics Data System (ADS)

Panta, Yogendra; Kudav, Ganesh

2011-03-01

Structural loads on solar panels include forces due to high wind, gravity, thermal expansion, and earthquakes. International Building Code (IBC) and the American Society of Civil Engineers are two commonly used approaches in solar industries to address wind loads. Minimum Design Loads for Buildings and Other Structures (ASCE 7-02) can be used to calculate wind uplift loads on roof-mounted solar panels. The present study is primarily focused on 2D and 3D modeling with steady, and turbulent flow over an inclined solar panel on the flat based roof to predict the wind forces for designing wind management system. For the numerical simulation, 3-D incompressible flow with the standard k- ɛ was adopted and commercial CFD software ANSYS FLUENT was used. Results were then validated with wind tunnel experiments with a good agreement. Solar panels with various aspect ratios for various high wind speeds and angle of attacks were modeled and simulated in order to predict the wind loads in various scenarios. The present study concluded to reduce the strong wind uplift by designing a guide plate or a deflector before the panel. Acknowledgments to Northern States Metal Inc., OH (GK & YP) and School of Graduate Studies of YSU for RP & URC 2009-2010 (YP).

Solar wind classification from a machine learning perspective

NASA Astrophysics Data System (ADS)

Heidrich-Meisner, V.; Wimmer-Schweingruber, R. F.

2017-12-01

It is a very well known fact that the ubiquitous solar wind comes in at least two varieties, the slow solar wind and the coronal hole wind. The simplified view of two solar wind types has been frequently challenged. Existing solar wind categorization schemes rely mainly on different combinations of the solar wind proton speed, the O and C charge state ratios, the Alfvén speed, the expected proton temperature and the specific proton entropy. In available solar wind classification schemes, solar wind from stream interaction regimes is often considered either as coronal hole wind or slow solar wind, although their plasma properties are different compared to "pure" coronal hole or slow solar wind. As shown in Neugebauer et al. (2016), even if only two solar wind types are assumed, available solar wind categorization schemes differ considerably for intermediate solar wind speeds. Thus, the decision boundary between the coronal hole and the slow solar wind is so far not well defined.In this situation, a machine learning approach to solar wind classification can provide an additional perspective.We apply a well-known machine learning method, k-means, to the task of solar wind classification in order to answer the following questions: (1) How many solar wind types can reliably be identified in our data set comprised of ten years of solar wind observations from the Advanced Composition Explorer (ACE)? (2) Which combinations of solar wind parameters are particularly useful for solar wind classification?Potential subtypes of slow solar wind are of particular interest because they can provide hints of respective different source regions or release mechanisms of slow solar wind.

Three-Fluid Magnetohydrodynamic Modeling of the Solar Wind in the Outer Heliosphere

NASA Technical Reports Server (NTRS)

Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.

2011-01-01

We have developed a three-fluid, fully three-dimensional magnetohydrodynamic model of the solar wind plasma in the outer heliosphere as a co-moving system of solar wind protons, electrons, and interstellar pickup protons, with separate energy equations for each species. Our approach takes into account the effects of electron heat conduction and dissipation of Alfvenic turbulence on the spatial evolution of the solar wind plasma and interplanetary magnetic fields. The turbulence transport model is based on the Reynolds decomposition of physical variables into mean and fluctuating components and uses the turbulent phenomenologies that describe the conversion of fluctuation energy into heat due to a turbulent cascade. We solve the coupled set of the three-fluid equations for the mean-field solar wind and the turbulence equations for the turbulence energy, cross helicity, and correlation length. The equations are written in the rotating frame of reference and include heating by turbulent dissipation, energy transfer from interstellar pickup protons to solar wind protons, and solar wind deceleration due to the interaction with the interstellar hydrogen. The numerical solution is constructed by the time relaxation method in the region from 0.3 to 100 AU. Initial results from the novel model are presented.

Interpretation of 3He variations in the solar wind

NASA Technical Reports Server (NTRS)

Coplan, M. A.; Ogilvie, K. W.; Geiss, J.; Bochsler, P.

1983-01-01

The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the solar wind almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of solar activity cycle 21, the maximum period, and the beginning of the descent towards solar minimum. Observations were made when the solar wind speed was between 300 and 620 km/s. For part of the period evidence for regular interplanetary magnetic sector structure was clear and a number of 3He flares occurred during this time.

Interpretation of He-3 abundance variations in the solar wind

NASA Technical Reports Server (NTRS)

Coplan, M. A.; Ogilvie, K. W.; Bochsler, P.; Geiss, J.

1984-01-01

The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the solar wind almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of solar activity cycle 21, the maximum period, and the beginning of the descent towards solar minimum. Observations were made when the solar wind speed was between 300 and 620 km/s. For part of the period evidence for regular interplanetary magnetic sector structure was clear and a number of He-3 flares occurred during this time.

Factors Controlling the Position of the Martian Magnetic Pileup Boundary

NASA Technical Reports Server (NTRS)

Crider, D. H.; Acuna, M.; Vignes, D.; Krymskii, A.; Breus, T.; Ness, N.

2003-01-01

The magnetic pileup boundary (MPB) at Mars is the position where the dominant ion of the plasma changes from solar wind protons to heavy ions of planetary origin. As such, it is the obstacle to solar wind ions. We investigate the factors that influence the shape and position of the magnetic pileup boundary at Mars in order to better understand the Martian obstacle to the solar wind. Employing MGS data, we determine how the Martian MPB moves in response to factors including solar wind pressure and crustal magnetic fields. We also study the factors affecting the thickness of the MPB. Further, we compare the magnetic pileup boundary to the magnetic barrier at Venus. Direct comparison aids in our interpretation of the physics involved in the solar wind interaction with planets lacking a significant intrinsic magnetic field.

Solar wind/local interstellar medium interaction including charge exchange with neural hydrogen

NASA Technical Reports Server (NTRS)

Pauls, H. Louis; Zank, Gary P.

1995-01-01

We present results from a hydrodynamic model of the interaction of the solar wind with the local interstellar medium (LISM), self-consistently taking into account the effects of charge exchange between the plasma component and the interstellar neutrals. The simulation is fully time dependent, and is carried out in two or three dimensions, depending on whether the helio-latitudinal dependence of the solar wind speed and number density (both giving rise to three dimensional effects) are included. As a first approximation it is assumed that the neutral component of the flow can be described by a single, isotropic fluid. Clearly, this is not the actual situation, since charge exchange with the supersonic solar wind plasma in the region of the nose results in a 'second' neutral fluid propagating in the opposite direction as that of the LISM neutrals.

Identifying and Characterizing Kinetic Instabilities using Solar Wind Observations of Non-Maxwellian Plasmas

NASA Astrophysics Data System (ADS)

Klein, K. G.

2016-12-01

Weakly collisional plasmas, of the type typically observed in the solar wind, are commonly in a state other than local thermodynamic equilibrium. This deviation from a Maxwellian velocity distribution can be characterized by pressure anisotropies, disjoint beams streaming at differing speeds, leptokurtic distributions at large energies, and other non-thermal features. As these features may be artifacts of dynamic processes, including the the acceleration and expansion of the solar wind, and as the free energy contained in these features can drive kinetic micro-instabilities, accurate measurement and modeling of these features is essential for characterizing the solar wind. After a review of these features, a technique is presented for the efficient calculation of kinetic instabilities associated with a general, non-Maxwellian plasma. As a proof of principle, this technique is applied to bi-Maxwellian systems for which kinetic instability thresholds are known, focusing on parameter scans including beams and drifting heavy minor ions. The application of this technique to fits of velocity distribution functions from current, forthcoming, and proposed missions including WIND, DSCOVR, Solar Probe Plus, and THOR, as well as the underlying measured distribution functions, is discussed. Particular attention is paid to the effects of instrument pointing and integration time, as well as potential deviation between instabilities associated with the Maxwellian fits and those associated with the observed, potentially non-Maxwellian, velocity distribution. Such application may further illuminate the role instabilities play in the evolution of the solar wind.

THE Role OF Anisotropy AND Intermittency IN Solar Wind/Magnetosphere Coupling

NASA Astrophysics Data System (ADS)

Jankovicova, D.; Voros, Z.

2006-12-01

Turbulent fluctuations are common in the solar wind as well as in the Earth's magnetosphere. The fluctuations of both magnetic field and plasma parameters exhibit non-Gaussian statistics. Neither the amplitude of these fluctuations nor their spectral characteristics can provide a full statistical description of multi-scale features in turbulence. It substantiates a statistical approach including the estimation of experimentally accessible statistical moments. In this contribution, we will directly estimate the third (skewness) and the fourth (kurtosis) statistical moments from the available time series of magnetic measurements in the solar wind (ACE and WIND spacecraft) and in the Earth's magnetosphere (SYM-H index). Then we evaluate how the statistical moments change during strong and weak solar wind/magnetosphere coupling intervals.

Solar Wind Interaction and Crustal Field Influences on Mars' Upper Ionosphere: MAVEN Observations Compared to Model Results

NASA Astrophysics Data System (ADS)

Luhmann, J. G.; Alvarez, K.; Curry, S.; Dong, C.; Ma, Y.; Bougher, S. W.; Benna, M.; Elrod, M. K.; Mahaffy, P. R.; Withers, P.; Girazian, Z.; Connerney, J. E. P.; Brain, D.; Jakosky, B. M.

2016-12-01

Since the two Viking Landers, progress on improving our global knowledge of the Martian ionosphere's characteristics has been limited by the available instrumentation and sampling geometries. In particular, while remote sensing and the lower energy plasma spectrometer observations on missions including MGS and MEX provided insights on the effects of the crustal magnetic fields of Mars and the solar wind interaction, these measurements did not allow the broader thermal ion surveys necessary to test our current understanding of the region between the exobase at 200 km altitude and the solar wind interaction boundary. In this study we use the MAVEN NGIMS thermal ion mass spectrometer observations from the prime mission year 2015 to construct some statistical pictures of the increasingly collisionless region of the ionosphere between 200 and 500 km where crustal field and solar wind interaction effects should begin to dominate its behavior. Comparisons with models of the solar wind interaction with Mars provide important global context for these observations, including the roles of system diversity associated with changing crustal field and interplanetary field orientations.

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

NASA Astrophysics Data System (ADS)

Jamlongkul, P.; Wannawichian, S.

2017-12-01

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

Potential Improvements in Space Weather Forecasting using New Products Developed for the Upcoming DSCOVR Solar Wind Mission

NASA Astrophysics Data System (ADS)

Cash, M. D.; Biesecker, D. A.; Reinard, A. A.

2013-05-01

The Deep Space Climate Observatory (DSCOVR) mission, which is scheduled for launch in late 2014, will provide real-time solar wind thermal plasma and magnetic measurements to ensure continuous monitoring for space weather forecasting. DSCOVR will be located at the L1 Lagrangian point and will include a Faraday cup to measure the proton and alpha components of the solar wind and a triaxial fluxgate magnetometer to measure the magnetic field in three dimensions. The real-time data provided by DSCOVR will be used to generate space weather applications and products that have been demonstrated to be highly accurate and provide actionable information for customers. We present several future space weather products currently under evaluation for development. New potential space weather products for use with DSCOVR real-time data include: automated shock detection, more accurate L1 to Earth delay time, automatic solar wind regime identification, and prediction of rotations in solar wind Bz within magnetic clouds. Additional ideas from the community on future space weather products are encouraged.

Oxygen Pickup Ions Measured by MAVEN Outside the Martian Bow Shock

NASA Astrophysics Data System (ADS)

Rahmati, A.; Cravens, T.; Larson, D. E.; Lillis, R. J.; Dunn, P.; Halekas, J. S.; Connerney, J. E. P.; Eparvier, F. G.; Thiemann, E.; Mitchell, D. L.; Jakosky, B. M.

2015-12-01

The MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft entered orbit around Mars on September 21, 2014 and has since been detecting energetic oxygen pickup ions by its SEP (Solar Energetic Particles) and SWIA (Solar Wind Ion Analyzer) instruments. The oxygen pickup ions detected outside the Martian bowshock and in the upstream solar wind are associated with the extended hot oxygen exosphere of Mars, which is created mainly by the dissociative recombination of molecular oxygen ions with electrons in the ionosphere. We use analytic solutions to the equations of motion of pickup ions moving in the undisturbed upstream solar wind magnetic and motional electric fields and calculate the flux of oxygen pickup ions at the location of MAVEN. Our model calculates the ionization rate of oxygen atoms in the exosphere based on the hot oxygen densities predicted by Rahmati et al. (2014), and the sources of ionization include photo-ionization, charge exchange, and electron impact ionization. The photo-ionization frequency is calculated using the FISM (Flare Irradiance Spectral Model) solar flux model, based on MAVEN EUVM (Extreme Ultra-Violet Monitor) measurements. The frequency of charge exchange between a solar wind proton and an oxygen atom is calculated using MAVEN SWIA solar wind proton flux measurements, and the electron impact ionization frequency is calculated based on MAVEN SWEA (Solar Wind Electron Analyzer) solar wind electron flux measurements. The solar wind magnetic field used in the model is from the measurements taken by MAVEN MAG (magnetometer) in the upstream solar wind. The good agreement between our predicted pickup oxygen fluxes and the MAVEN SEP and SWIA measured ones confirms detection of oxygen pickup ions and these model-data comparisons can be used to constrain models of hot oxygen densities and photochemical escape flux.

Convective and radiative components of wind chill in sheep: Estimation from meteorological records

NASA Astrophysics Data System (ADS)

Brown, D.; Mount, L. E.

1987-06-01

Wind chill is defined as the excess of sensible heat loss over what would occur at zero wind speed with other conditions unchanged. Wind chill can be broken down into a part that is determined by air temperature and a radiative part that comprises wind-dependent effects on additional long-wave radiative exchange and on solar radiation (by reducing solar warming). Radiative exchange and gain from solar radiation are affected by changes that are produced by wind in both surface and fleece insulations. Coefficients are derived for (a) converting the components of sensible heat exchange (air-temperature-dependent including both convective and associated long-wave radiative, additional long-wave radiative and solar) into the components of the total heat loss that are associated with wind and (b) for calculating equivalent air temperature changes. The coefficients contain terms only in wind speed, wetting of the fleece and fleece depth; these determine the external insulation. Calculation from standard meteorological records, using Plymouth and Aberdeen in 1973 as examples, indicate that in April September 1973 at Plymouth reduction in effective solar warming constituted 28% of the 24-h total wind chill, and 7% in the other months of the year combined; at Aberdeen the corresponding percentages were 25% and 6%. Mean hour-of-day estimates for the months of April and October showed that at midday reduction in solar warming due to wind rose to the order of half the air-temperature-dependent component of wind chill, with a much smaller effect in January. For about six hours at midday in July reduction in solar warming due to wind was similar in magnitude to the air-temperature-dependent component. It is concluded that realistic estimates of wind chill cannot be obtained unless the effect of solar radiation is taken into account. Failure to include solar radiation results not only in omitting solar warming but also in omitting the effects of wind in reducing that warming. The exchange of sensible (non-evaporative) heat loss between a homeothermic animal and its environment can be divided into two parts: one part is due to the temperature difference between the animal and the surrounding air, and the other part is due to additional long-wave radiative exchange between animal and environment and to solar radiation. Both parts of the heat exchange are determined in magnitude by the animal's thermal insulation, which is itself affected by windspeed and wetting. Wind diminishes as animal's external insulation, so increasing heat loss under all conditions when the air temperature is lower than the animal's surface temperature: this effect is termed wind chill. Wind chill has previously been investigated more commonly in relation to man (Burton an Edholm, 1955; Smithson and Baldwin, 1978; Mumford, 1979; Baldwin and Smithson, 1979). This paper is concerned with the separate contributions to wind chill calculated for sheep that can be associated with convective and radiative heat exchanges.

Optimal Management of DoD Lands for Military Training, Ecosystem Services, and Renewable Energy Generation: Framework and Data Requirements

DTIC Science & Technology

2013-01-01

by at least 25% by 2025. To achieve this ambitious goal, DoD is considering a diverse energy portfolio that includes wind , solar, geothermal...generated power (bioenergy). wind , solar, and bioenergy sources each have significant land-management implications, so this third land-use re- quirement...production, the adverse impacts of conflicting requirements can be minimized. The regional differences in wind , solar, and bioenergy potential

Smart Microgrid Energy Management Controls for Improved Energy Efficiency and Renewables Integration at DoD Installations

DTIC Science & Technology

2013-04-01

products for energy generation, including solar, wind , and gas turbines , energy storage, power conversion, grid integration, and software for...potential security advantages over centralized systems • DER promote fuel diversity (e.g., biomass, landfill gas, flare gas, wind , solar) and...therefore reduce overall energy price volatility • Renewable DER such as wind and solar photovoltaics provide emissions-free energy • DER offer a quicker

Comets as natural laboratories: Interpretations of the structure of the inner heliosphere

NASA Astrophysics Data System (ADS)

Ramanjooloo, Yudish; Jones, Geraint H.; Coates, Andrew J.; Owens, Mathew J.

2015-11-01

Much has been learnt about the heliosphere’s structure from in situ solar wind spacecraft observations. Their coverage is however limited in time and space. Comets can be considered to be natural laboratories of the inner heliosphere, as their ion tails trace the solar wind flow. Solar wind conditions influence comets’ induced magnetotails, formed through the draping of the heliospheric magnetic field by the velocity shear in the mass-loaded solar wind.I present a novel imaging technique and software to exploit the vast catalogues of amateur and professional images of comet ion tails. My projection technique uses the comet’s orbital plane to sample its ion tail as a proxy for determining multi-latitudinal radial solar wind velocities in each comet’s vicinity. Making full use of many observing stations from astrophotography hobbyists to professional observatories and spacecraft, this approach is applied to several comets observed in recent years. This work thus assesses the validity of analysing comets’ ion tails as complementary sources of information on dynamical heliospheric phenomena and the underlying continuous solar wind.Complementary velocities, measured from folding ion rays and a velocity profile map built from consecutive images, are derived as an alternative means of quantifying the solar wind-cometary ionosphere interaction, including turbulent transient phenomena such as coronal mass ejections. I review the validity of these techniques by comparing near-Earth comets to solar wind MHD models (ENLIL) in the inner heliosphere and extrapolated measurements by ACE to the orbit of comet C/2004 Q2 (Machholz), a near-Earth comet. My radial velocities are mapped back to the solar wind source surface to identify sources of the quiescent solar wind and heliospheric current sheet crossings. Comets were found to be good indicators of solar wind structure, but the quality of results is strongly dependent on the observing geometry.

Statistical Methods for Quantifying the Variability of Solar Wind Transients of All Sizes

NASA Astrophysics Data System (ADS)

Tindale, E.; Chapman, S. C.

2016-12-01

The solar wind is inherently variable across a wide range of timescales, from small-scale turbulent fluctuations to the 11-year periodicity induced by the solar cycle. Each solar cycle is unique, and this change in overall cycle activity is coupled from the Sun to Earth via the solar wind, leading to long-term trends in space weather. Our work [Tindale & Chapman, 2016] applies novel statistical methods to solar wind transients of all sizes, to quantify the variability of the solar wind associated with the solar cycle. We use the same methods to link solar wind observations with those on the Sun and Earth. We use Wind data to construct quantile-quantile (QQ) plots comparing the statistical distributions of multiple commonly used solar wind-magnetosphere coupling parameters between the minima and maxima of solar cycles 23 and 24. We find that in each case the distribution is multicomponent, ranging from small fluctuations to extreme values, with the same functional form at all phases of the solar cycle. The change in PDF is captured by a simple change of variables, which is independent of the PDF model. Using this method we can quantify the quietness of the cycle 24 maximum, identify which variable drives the changing distribution of composite parameters such as ɛ, and we show that the distribution of ɛ is less sensitive to changes in its extreme values than that of its constituents. After demonstrating the QQ method on solar wind data, we extend the analysis to include solar and magnetospheric data spanning the same time period. We focus on GOES X-ray flux and WDC AE index data. Finally, having studied the statistics of transients across the full distribution, we apply the same method to time series of extreme bursts in each variable. Using these statistical tools, we aim to track the solar cycle-driven variability from the Sun through the solar wind and into the Earth's magnetosphere. Tindale, E. and S.C. Chapman (2016), Geophys. Res. Lett., 43(11), doi: 10.1002/2016GL068920.

Recent Optical and SEM Characterization of Genesis Solar Wind Concentrator Diamond on Silicon Collector

NASA Technical Reports Server (NTRS)

Allton, Judith H.; Rodriquez, M. C.; Burkett, P. J.; Ross, D. K.; Gonzalez, C. P.; McNamara, K. M.

2013-01-01

One of the 4 Genesis solar wind concentrator collectors was a silicon substrate coated with diamond-like carbon (DLC) in which to capture solar wind. This material was designed for analysis of solar nitrogen and noble gases [1, 2]. This particular collector fractured during landing, but about 80% of the surface was recovered, including a large piece which was subdivided in 2012 [3, 4, 5]. The optical and SEM imaging and analysis described below supports the subdivision and allocation of the diamond-on-silicon (DOS) concentrator collector.

The structure of the solar wind in the inner heliosphere

NASA Astrophysics Data System (ADS)

Lee, Christina On-Yee

2010-12-01

This dissertation is devoted to expanding our understanding of the solar wind structure in the inner heliosphere and variations therein with solar activity. Using spacecraft observations and numerical models, the origins of the large-scale structures and long-term trends of the solar wind are explored in order to gain insights on how our Sun determines the space environments of the terrestrial planets. I use long term measurements of the solar wind density, velocity, interplanetary magnetic field, and particles, together with models based on solar magnetic field data, to generate time series of these properties that span one solar rotation (˜27 days). From these time series, I assemble and obtain the synoptic overviews of the solar wind properties. The resulting synoptic overviews show that the solar wind around Mercury, Venus, Earth, and Mars is a complex co-rotating structure with recurring features and occasional transients. During quiet solar conditions, the heliospheric current sheet, which separates the positive interplanetary magnetic field from the negative, usually has a remarkably steady two- or four-sector structure that persists for many solar rotations. Within the sector boundaries are the slow and fast speed solar wind streams that originate from the open coronal magnetic field sources that map to the ecliptic. At the sector boundaries, compressed high-density and the related high-dynamic pressure ridges form where streams from different coronal source regions interact. High fluxes of energetic particles also occur at the boundaries, and are seen most prominently during the quiet solar period. The existence of these recurring features depends on how long-lived are their source regions. In the last decade, 3D numerical solar wind models have become more widely available. They provide important scientific tools for obtaining a more global view of the inner heliosphere and of the relationships between conditions at Mercury, Venus, Earth, and Mars. When I compare the model results with observations for periods outside of solar wind disturbances, I find that the models do a good job of simulating at least the steady, large-scale, ambient solar wind structure. However, it remains a challenge to accurately model the solar wind during active solar conditions. During these times, solar transients such as coronal mass ejections travel through interplanetary space and disturb the ambient solar wind, producing a far less predictable and modelable space environment. However, such conditions may have the greatest impact on the planets - especially on their atmospheres and magnetospheres. I therefore also consider the next steps in modeling, toward including active conditions.

76 FR 23230 - Segregation of Lands-Renewable Energy

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-26

... within the wind energy right-of- way application areas in FY 2009 and 2010, we estimate the total cost of... transmission facilities that could be used to carry the power generated from a specific wind or solar energy..., public lands included in a pending or future wind or solar energy generation right-of-way (ROW...

75 FR 64776 - Initiation of Section 302 Investigation and Request for Public Comment: China-Acts, Policies and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-20

... variety of products, including wind turbines; discrimination against foreign companies and goods... production and use of energy. These are the products necessary to produce energy from wind, solar, biomass... policies to stimulate and protect its domestic producers of green technology, from wind and solar energy...

THREE-DIMENSIONAL MAGNETOHYDRODYNAMIC MODELING OF THE SOLAR WIND INCLUDING PICKUP PROTONS AND TURBULENCE TRANSPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Usmanov, Arcadi V.; Matthaeus, William H.; Goldstein, Melvyn L., E-mail: arcadi.usmanov@nasa.gov

2012-07-20

To study the effects of interstellar pickup protons and turbulence on the structure and dynamics of the solar wind, we have developed a fully three-dimensional magnetohydrodynamic solar wind model that treats interstellar pickup protons as a separate fluid and incorporates the transport of turbulence and turbulent heating. The governing system of equations combines the mean-field equations for the solar wind plasma, magnetic field, and pickup protons and the turbulence transport equations for the turbulent energy, normalized cross-helicity, and correlation length. The model equations account for photoionization of interstellar hydrogen atoms and their charge exchange with solar wind protons, energy transfermore » from pickup protons to solar wind protons, and plasma heating by turbulent dissipation. Separate mass and energy equations are used for the solar wind and pickup protons, though a single momentum equation is employed under the assumption that the pickup protons are comoving with the solar wind protons. We compute the global structure of the solar wind plasma, magnetic field, and turbulence in the region from 0.3 to 100 AU for a source magnetic dipole on the Sun tilted by 0 Degree-Sign -90 Degree-Sign and compare our results with Voyager 2 observations. The results computed with and without pickup protons are superposed to evaluate quantitatively the deceleration and heating effects of pickup protons, the overall compression of the magnetic field in the outer heliosphere caused by deceleration, and the weakening of corotating interaction regions by the thermal pressure of pickup protons.« less

Evolving Waves and Turbulence in the Outer Corona and Inner Heliosphere: The Accelerating Expanding Box

NASA Astrophysics Data System (ADS)

Tenerani, Anna; Velli, Marco

2017-07-01

Alfvénic fluctuations in the solar wind display many properties reflecting an ongoing nonlinear cascade, e.g., a well-defined spectrum in frequency, together with some characteristics more commonly associated with the linear propagation of waves from the Sun, such as the variation of fluctuation amplitude with distance, dominated by solar wind expansion effects. Therefore, both nonlinearities and expansion must be included simultaneously in any successful model of solar wind turbulence evolution. Because of the disparate spatial scales involved, direct numerical simulations of turbulence in the solar wind represent an arduous task, especially if one wants to go beyond the incompressible approximation. Indeed, most simulations neglect solar wind expansion effects entirely. Here we develop a numerical model to simulate turbulent fluctuations from the outer corona to 1 au and beyond, including the sub-Alfvénic corona. The accelerating expanding box (AEB) extends the validity of previous expanding box models by taking into account both the acceleration of the solar wind and the inhomogeneity of background density and magnetic field. Our method incorporates a background accelerating wind within a magnetic field that naturally follows the Parker spiral evolution using a two-scale analysis in which the macroscopic spatial effect coupling fluctuations with background gradients becomes a time-dependent coupling term in a homogeneous box. In this paper we describe the AEB model in detail and discuss its main properties, illustrating its validity by studying Alfvén wave propagation across the Alfvén critical point.

An Investigation of the Large Scale Evolution and Topology of Coronal Mass Ejections in the Solar Wind

NASA Technical Reports Server (NTRS)

Riley, Peter

2000-01-01

This investigation is concerned with the large-scale evolution and topology of coronal mass ejections (CMEs) in the solar wind. During this reporting period we have focused on several aspects of CME properties, their identification and their evolution in the solar wind. The work included both analysis of Ulysses and ACE observations as well as fluid and magnetohydrodynamic simulations. In addition, we analyzed a series of "density holes" observed in the solar wind, that bear many similarities with CMEs. Finally, this work was communicated to the scientific community at three meetings and has led to three scientific papers that are in various stages of review.

Shapes of strong shock fronts in an inhomogeneous solar wind

NASA Technical Reports Server (NTRS)

Heinemann, M. A.; Siscoe, G. L.

1974-01-01

The shapes expected for solar-flare-produced strong shock fronts in the solar wind have been calculated, large-scale variations in the ambient medium being taken into account. It has been shown that for reasonable ambient solar wind conditions the mean and the standard deviation of the east-west shock normal angle are in agreement with experimental observations including shocks of all strengths. The results further suggest that near a high-speed stream it is difficult to distinguish between corotating shocks and flare-associated shocks on the basis of the shock normal alone. Although the calculated shapes are outside the range of validity of the linear approximation, these results indicate that the variations in the ambient solar wind may account for large deviations of shock normals from the radial direction.

The Genesis Mission: Solar Wind Conditions, and Implications for the FIP Fractionation of the Solar Wind.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reisenfeld, D. B.; Wiens, R. C.; Barraclough, B. L.

2005-01-01

The NASA Genesis mission collected solar wind on ultrapure materials between November 30, 2001 and April 1, 2004. The samples were returned to Earth September 8, 2004. Despite the hard landing that resulted from a failure of the avionics to deploy the parachute, many samples were returned in a condition that will permit analyses. Sample analyses of these samples should give a far better understanding of the solar elemental and isotopic composition (Burnett et al. 2003). Further, the photospheric composition is thought to be representative of the solar nebula, so that the Genesis mission will provide a new baseline formore » the average solar nebula composition with which to compare present-day compositions of planets, meteorites, and asteroids. Sample analysis is currently underway. The Genesis samples must be placed in the context of the solar and solar wind conditions under which they were collected. Solar wind is fractionated from the photosphere by the forces that accelerate the ions off of the Sun. This fractionation appears to be ordered by the first ionization potential (FIP) of the elements, with the tendency for low-FIP elements to be over-abundant in the solar wind relative to the photosphere, and high-FIP elements to be under-abundant (e.g. Geiss, 1982; von Steiger et al., 2000). In addition, the extent of elemental fractionation differs across different solarwind regimes. Therefore, Genesis collected solar wind samples sorted into three regimes: 'fast wind' or 'coronal hole' (CH), 'slow wind' or 'interstream' (IS), and 'coronal mass ejection' (CME). To carry this out, plasma ion and electron spectrometers (Barraclough et al., 2003) continuously monitored the solar wind proton density, velocity, temperature, the alpha/proton ratio, and angular distribution of suprathermal electrons, and those parameters were in turn used in a rule-based algorithm that assigned the most probable solar wind regime (Neugebauer et al., 2003). At any given time, only one of three regime-specific collectors (CH, IS, or CME) was exposed to the solar wind. Here we report on the regime-specific solar wind conditions from in-situ instruments over the course of the collection period. Further, we use composition data from the SWICS (Solar Wind Ion Composition Spectrometer) instrument on ACE (McComas et al., 1998) to examine the FIP fractionation between solar wind regimes, and make a preliminary comparison of these to the FIP analysis of Ulysses/SWICS composition data (von Steiger et al. 2000). Our elemental fractionation study includes a reevaluation of the Ulysses FIP analysis in light of newly reported photospheric abundance data (Asplund, Grevesse & Sauval, 2005). The new abundance data indicate a metallicity (Z/X) for the Sun almost a factor of two lower than that reported in the widely used compilation of Anders & Grevesse (1989). The new photospheric abundances suggest a lower degree of solar wind fractionation than previously reported by von Steiger et al. (2000) for the first Ulysses polar orbit (1991-1998).« less

Statistical Similarities Between WSA-ENLIL+Cone Model and MAVEN in Situ Observations From November 2014 to March 2016

NASA Astrophysics Data System (ADS)

Lentz, C. L.; Baker, D. N.; Jaynes, A. N.; Dewey, R. M.; Lee, C. O.; Halekas, J. S.; Brain, D. A.

2018-02-01

Normal solar wind flows and intense solar transient events interact directly with the upper Martian atmosphere due to the absence of an intrinsic global planetary magnetic field. Since the launch of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, there are now new means to directly observe solar wind parameters at the planet's orbital location for limited time spans. Due to MAVEN's highly elliptical orbit, in situ measurements cannot be taken while MAVEN is inside Mars' magnetosheath. To model solar wind conditions during these atmospheric and magnetospheric passages, this research project utilized the solar wind forecasting capabilities of the WSA-ENLIL+Cone model. The model was used to simulate solar wind parameters that included magnetic field magnitude, plasma particle density, dynamic pressure, proton temperature, and velocity during a four Carrington rotation-long segment. An additional simulation that lasted 18 Carrington rotations was then conducted. The precision of each simulation was examined for intervals when MAVEN was in the upstream solar wind, that is, with no exospheric or magnetospheric phenomena altering in situ measurements. It was determined that generalized, extensive simulations have comparable prediction capabilities as shorter, more comprehensive simulations. Generally, this study aimed to quantify the loss of detail in long-term simulations and to determine if extended simulations can provide accurate, continuous upstream solar wind conditions when there is a lack of in situ measurements.

Turbulent Heating and Wave Pressure in Solar Wind Acceleration Modeling: New Insights to Empirical Forecasting of the Solar Wind

NASA Astrophysics Data System (ADS)

Woolsey, L. N.; Cranmer, S. R.

2013-12-01

The study of solar wind acceleration has made several important advances recently due to improvements in modeling techniques. Existing code and simulations test the competing theories for coronal heating, which include reconnection/loop-opening (RLO) models and wave/turbulence-driven (WTD) models. In order to compare and contrast the validity of these theories, we need flexible tools that predict the emergent solar wind properties from a wide range of coronal magnetic field structures such as coronal holes, pseudostreamers, and helmet streamers. ZEPHYR (Cranmer et al. 2007) is a one-dimensional magnetohydrodynamics code that includes Alfven wave generation and reflection and the resulting turbulent heating to accelerate solar wind in open flux tubes. We present the ZEPHYR output for a wide range of magnetic field geometries to show the effect of the magnetic field profiles on wind properties. We also investigate the competing acceleration mechanisms found in ZEPHYR to determine the relative importance of increased gas pressure from turbulent heating and the separate pressure source from the Alfven waves. To do so, we developed a code that will become publicly available for solar wind prediction. This code, TEMPEST, provides an outflow solution based on only one input: the magnetic field strength as a function of height above the photosphere. It uses correlations found in ZEPHYR between the magnetic field strength at the source surface and the temperature profile of the outflow solution to compute the wind speed profile based on the increased gas pressure from turbulent heating. With this initial solution, TEMPEST then adds in the Alfven wave pressure term to the modified Parker equation and iterates to find a stable solution for the wind speed. This code, therefore, can make predictions of the wind speeds that will be observed at 1 AU based on extrapolations from magnetogram data, providing a useful tool for empirical forecasting of the sol! ar wind.

The sun and heliosphere at solar maximum

NASA Technical Reports Server (NTRS)

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

Gaussianity versus intermittency in solar system plasma turbulence

NASA Astrophysics Data System (ADS)

Echim, M.

2014-12-01

Statistical properties of plasma and magnetic field fluctuations exhibit features linked with the dynamics of the targeted system and sometimes with the physical processes that are at the origin of these fluctuations. Intermittency is sometimes discussed in terms of non-Gaussianity of the Probability Distribution Functions (PDFs) of fluctuations for ranges of spatio/temporal scales. Some examples of self-similarity have been however shown for PDFs whose wings are not Gaussian. In this study we discuss intermittency in terms of non-Gaussianity as well as scale dependence of the higher order moments of PDFs, in particular the flatness. We use magnetic field and plasma data from several space missions, in the solar wind (Ulysses, Cluster, and Venus Express), and in the planetary magnetosheaths (Cluster and Venus Express). We analyze Ulysses data that satisfy a consolidated set of selection criteria able to identify "pure" fast and slow wind. We investigate Venus Express data close to the orbital apogee, in the solar wind, at 0.72 AU, and in the Venus magnetosheath. We study Cluster data in the solar wind (for time intervals not affected by planetary ions effects), and the magnetosheath. We organize our results in three solar wind data bases (one for the solar maximum, 1999-2001, two for the solar minimum, 1997-1998 and respectively, 2007-2008), and two planetary databases (one for the solar maximum, 2000-2001, that includes PDFs obtained in the terrestrial magnetosphere, and one for the solar minimum, 2007-2008, that includes PDFs obtained in the terrestrial and Venus magnetospheres and magnetosheaths). In addition to investigating the statistical properties of fluctuations for the minimum and maximum of the solar cycle we also analyze the similarities and differences between fast and slow wind. We emphasize the importance of our data survey and analysis in the context of understanding the solar wind turbulence and complexity, and the exploitation of data bases and as a first step towards developing a (virtual) laboratory for studying solar system plasma turbulence and intermittency. Research supported by the European FP7 Programme (grant agreement 313038/STORM), and a grant of the Romanian CNCS -UEFISCDI, project number PN-II-ID-PCE-2012-4-0418.

Contributions to the Fourth Solar Wind Conference. [interplanetary magnetic fields and medium

NASA Technical Reports Server (NTRS)

Acuna, M. H.; Behannon, K. W.; Burlaga, L. F.; Lepping, R.; Ness, N.; Ogilvie, K.; Pizzo, J.

1979-01-01

Recent results in interplanetary physics are examined. These include observations of shock waves and post-shock magnetic fields made by Voyager 1, 2; observations of the electron temperature as a function of distance between 1.36 AU and 2.25 AU; and observations of the structure of sector boundaries observed by Helios 1. A theory of electron energy transport in the collisionless solar wind is presented, and compared with observations. Alfven waves and Alvenic fluctuations in the solar wind are also discussed.

THE CONTRIBUTION OF CORONAL JETS TO THE SOLAR WIND

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lionello, R.; Török, T.; Titov, V. S.

Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy content of the corona and solar wind, but the extent of these contributions remains uncertain. We have recently modeled the formation and evolution of coronal jets using a three-dimensional (3D) magnetohydrodynamic (MHD) code with thermodynamics in a large spherical domain that includes the solar wind. Our model is coupled to 3D MHD flux-emergence simulations, i.e., we use boundary conditions provided by such simulationsmore » to drive a time-dependent coronal evolution. The model includes parametric coronal heating, radiative losses, and thermal conduction, which enables us to simulate the dynamics and plasma properties of coronal jets in a more realistic manner than done so far. Here, we employ these simulations to calculate the amount of mass and energy transported by coronal jets into the outer corona and inner heliosphere. Based on observed jet-occurrence rates, we then estimate the total contribution of coronal jets to the mass and energy content of the solar wind to (0.4–3.0)% and (0.3–1.0)%, respectively. Our results are largely consistent with the few previous rough estimates obtained from observations, supporting the conjecture that coronal jets provide only a small amount of mass and energy to the solar wind. We emphasize, however, that more advanced observations and simulations (including parametric studies) are needed to substantiate this conjecture.« less

The GENESIS Mission: Solar Wind Isotopic and Elemental Compositions and Their Implications

NASA Astrophysics Data System (ADS)

Wiens, R. C.; Burnett, D. S.; McKeegan, K. D.; Kallio, A. P.; Mao, P. H.; Heber, V. S.; Wieler, R.; Meshik, A.; Hohenberg, C. M.; Mabry, J. C.; Gilmour, J.; Crowther, S. A.; Reisenfeld, D. B.; Jurewicz, A.; Marty, B.; Pepin, R. O.; Barraclough, B. L.; Nordholt, J. E.; Olinger, C. T.; Steinberg, J. T.

2008-12-01

The GENESIS mission was a novel NASA experiment to collect solar wind at the Earth's L1 point for two years and return it for analysis. The capsule crashed upon re-entry in 2004, but many of the solar-wind collectors were recovered, including separate samples of coronal hole, interstream, and CME material. Laboratory analyses of these materials have allowed higher isotopic precision than possible with current in-situ detectors. To date GENESIS results have been obtained on isotopes of O, He, Ne, Ar, Kr, and Xe on the order of 1% accuracy and precision, with poorer uncertainty on Xe isotopes and significantly better uncertainties on the lighter noble gases. Elemental abundances are available for the above elements as well as Mg, Si, and Fe. When elemental abundances are compared with other in situ solar wind measurements, agreement is generally quite good. One exception is the Ne elemental abundance, which agrees with Ulysses and Apollo SWC results, but not with ACE. Neon is of particular interest because of the uncertainty in the solar Ne abundance, which has significant implications for the standard solar model. Helium isotopic results of material from the different solar wind regimes collected by GENESIS is consistent with isotopic fractionation predictions of the Coulomb drag model, suggesting that isotopic fractionation corrections need to be applied to heavier elements as well when extrapolating solar wind to solar compositions. Noble gas isotopic compositions from GENESIS are consistent with those obtained for solar wind trapped in lunar grains, but have for the first time yielded a very precise Ar isotopic result. Most interesting for cosmochemistry is a preliminary oxygen isotopic result from GENESIS which indicates a solar enrichment of ~4% in 16O relative to the planets, consistent with a photolytic self-shielding phenomenon during solar system formation. Analyses of solar wind N and C isotopes may further elucidate this phenomenon. Preliminary results from GENESIS have been reported for N, and results are still pending for C.

Evolving Waves and Turbulence in the Outer Corona and Inner Heliosphere: The Accelerating Expanding Box

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenerani, Anna; Velli, Marco

Alfvénic fluctuations in the solar wind display many properties reflecting an ongoing nonlinear cascade, e.g., a well-defined spectrum in frequency, together with some characteristics more commonly associated with the linear propagation of waves from the Sun, such as the variation of fluctuation amplitude with distance, dominated by solar wind expansion effects. Therefore, both nonlinearities and expansion must be included simultaneously in any successful model of solar wind turbulence evolution. Because of the disparate spatial scales involved, direct numerical simulations of turbulence in the solar wind represent an arduous task, especially if one wants to go beyond the incompressible approximation. Indeed,more » most simulations neglect solar wind expansion effects entirely. Here we develop a numerical model to simulate turbulent fluctuations from the outer corona to 1 au and beyond, including the sub-Alfvénic corona. The accelerating expanding box (AEB) extends the validity of previous expanding box models by taking into account both the acceleration of the solar wind and the inhomogeneity of background density and magnetic field. Our method incorporates a background accelerating wind within a magnetic field that naturally follows the Parker spiral evolution using a two-scale analysis in which the macroscopic spatial effect coupling fluctuations with background gradients becomes a time-dependent coupling term in a homogeneous box. In this paper we describe the AEB model in detail and discuss its main properties, illustrating its validity by studying Alfvén wave propagation across the Alfvén critical point.« less

Some remarks on waves in the solar wind

NASA Technical Reports Server (NTRS)

Kellogg, Paul J.

1995-01-01

Waves are significant to the solar wind in two ways as modifiers of the particle distribution functions, and as diagnostics. In addition, the solar wind serves as an important laboratory for the study of plasma wave processes, as it is possible to make detailed measurements of phenomena which are too small to be easily measured by laboratory sized sensors. There are two areas where waves (we include discontinuities under this heading) must make important modifications of the distribution functions: in accelerating the alpha particles to higher speeds than the protons (Marsch et al.) and in accelerating the solar wind itself. A third area is possibly in maintaining the relative isotropy of the solar wind ion distribution in the solar wind rest frame. As the solar wind is nearly collisionless, the ions should conserve magnetic moment in rushing out from the sun, and therefore Tperp/B should be relatively constant, but it is obviously not. This has not received much attention. The waves, both electromagnetic and electrostatic, which are pan of the solar Type 111 burst phenomenon, have been extensively studied as examples of nonlinear plasma phenomena, and also used as remote sensors to trace the solar magnetic field. The observations made by Ulysses show that the field can be traced in this way out to perhaps a little more than an A.U., but then the electromagnetic pan of the type 111 burst fades out. Nevertheless, sometimes Langmuir waves appear at Ulysses at an appropriate extrapolated time. This seems to support the picture in which the electromagnetic waves at the fundamental plasma frequency are trapped in density fluctuations. Langmuir waves in the solar wind are usually in quasi-thermal equilibrium quasi because the solar wind itself is not isothermal. The Observatory of Paris group (Steinberg. Meyer-Vernet, Hoang) has exploited this with an experiment on WIND which is capable of providing density and temperature on a faster time scale than hitherto. Recently it has been found that Langmuir waves are associated with magnetic holes. This may help to elucidate the nature of magnetic holes. Nonlinear processes are important in the transformation of wave energy to panicle energy. Some recent examples from WIND data will be shown.

The Third Solar Wind Conference: A summary

NASA Technical Reports Server (NTRS)

Russell, C. T.

1974-01-01

The Third Solar Wind Conference consisted of nine sessions. The following subjects were discussed: (1) solar abundances; (2) the history and evolution of the solar wind; (3) the structure and dynamics of the solar corona; (4) macroscopic and microscopic properties of the solar wind; (5) cosmic rays as a probe of the solar wind; (6) the structure and dynamics of the solar wind; (7) spatial gradients; (8) stellar winds; and (9) interactions with objects in the solar wind. The invited and contributed talks presented at the conference are summarized.

Hydrodynamic Models of Line-Driven Accretion Disk Winds III: Local Ionization Equilibrium

NASA Technical Reports Server (NTRS)

Pereyra, Nicolas Antonio; Kallman, Timothy R.; White, Nicholas E. (Technical Monitor)

2002-01-01

We present time-dependent numerical hydrodynamic models of line-driven accretion disk winds in cataclysmic variable systems and calculate wind mass-loss rates and terminal velocities. The models are 2.5-dimensional, include an energy balance condition with radiative heating and cooling processes, and includes local ionization equilibrium introducing time dependence and spatial dependence on the line radiation force parameters. The radiation field is assumed to originate in an optically thick accretion disk. Wind ion populations are calculated under the assumption that local ionization equilibrium is determined by photoionization and radiative recombination, similar to a photoionized nebula. We find a steady wind flowing from the accretion disk. Radiative heating tends to maintain the temperature in the higher density wind regions near the disk surface, rather than cooling adiabatically. For a disk luminosity L (sub disk) = solar luminosity, white dwarf mass M(sub wd) = 0.6 solar mass, and white dwarf radii R(sub wd) = 0.01 solar radius, we obtain a wind mass-loss rate of M(sub wind) = 4 x 10(exp -12) solar mass yr(exp -1) and a terminal velocity of approximately 3000 km per second. These results confirm the general velocity and density structures found in our earlier constant ionization equilibrium adiabatic CV wind models. Further we establish here 2.5D numerical models that can be extended to QSO/AGN winds where the local ionization equilibrium will play a crucial role in the overall dynamics.

Mars atmospheric losses induced by the solar wind: current knowledge and perspective

NASA Astrophysics Data System (ADS)

Ermakov, Vladimir; Zelenyi, Lev; Vaisberg, Oleg; Sementsov, Egor; Dubinin, Eduard

2017-04-01

Solar wind induced atmospheric losses have been studied since earlier 1970th. Several loss channels have been identified including pick-up of exospheric photo-ions and ionospheric ions escape. Measurements performed during several solar cycles showed variation of these losses by about factor of 10, being largest at maximum solar activity. MAVEN spacecraft equipped with comprehensive set of instruments with high temporal and mass resolution operating at Mars since fall 2014 ensures much better investigation of solar wind enforcing Martian environment, Mars atmospheric losses processes and mass loss rate. These issues are very important for understanding of Martian atmospheric evolution including water loss during cosmogonic time. Simultaneous observations by MAVEN and MEX spacecraft open the new perspective in study of Martian environment. In this report we discuss results of past and current missions and preliminary analysis of heavy ions escape using simultaneous measurements of MEX and MAVEN spacecraft.

Western Wind and Solar Integration Study Phase 3A: Low Levels of Synchronous Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Nicholas W.; Leonardi, Bruno; D'Aquila, Robert

The stability of the North American electric power grids under conditions of high penetrations of wind and solar is a significant concern and possible impediment to reaching renewable energy goals. The 33% wind and solar annual energy penetration considered in this study results in substantial changes to the characteristics of the bulk power system. This includes different power flow patterns, different commitment and dispatch of existing synchronous generation, and different dynamic behavior from wind and solar generation. The Western Wind and Solar Integration Study (WWSIS), sponsored by the U.S. Department of Energy, is one of the largest regional solar andmore » wind integration studies to date. In multiple phases, it has explored different aspects of the question: Can we integrate large amounts of wind and solar energy into the electric power system of the West? The work reported here focused on the impact of low levels of synchronous generation on the transient stability performance in one part of the region in which wind generation has displaced synchronous thermal generation under highly stressed, weak system conditions. It is essentially an extension of WWSIS-3. Transient stability, the ability of the power system to maintain synchronism among all elements following disturbances, is a major constraint on operations in many grids, including the western U.S. and Texas systems. These constraints primarily concern the performance of the large-scale bulk power system. But grid-wide stability concerns with high penetrations of wind and solar are still not thoroughly understood. This work focuses on 'traditional' fundamental frequency stability issues, such as maintaining synchronism, frequency, and voltage. The objectives of this study are to better understand the implications of low levels of synchronous generation and a weak grid on overall system performance by: 1) Investigating the Western Interconnection under conditions of both high renewable generation (e.g., wind and solar) and low synchronous generation (e.g., significant coal power plant decommitment or retirement); and 2) Analyzing both the large-scale stability of the Western Interconnection and regional stability issues driven by more geographically dispersed renewable generation interacting with a transmission grid that evolved with large, central station plants at key nodes. As noted above, the work reported here is an extension of the research performed in WWSIS-3.« less

Analysis of Solar Wind Precipitation on Mars Using MAVEN/SWIA Observations of Spacecraft-Scattered Ions

NASA Astrophysics Data System (ADS)

Lue, C.; Halekas, J. S.

2017-12-01

Particle sensors on the MAVEN spacecraft (SWIA, SWEA, STATIC) observe precipitating solar wind ions during MAVEN's periapsis passes in the Martian atmosphere (at 120-250 km altitude). The signature is observed as positive and negative particles at the solar wind energy, traveling away from the Sun. The observations can be explained by the solar wind penetrating the Martian magnetic barrier in the form of energetic neutral atoms (ENAs) due to charge-exchange with the Martian hydrogen corona, and then being reionized in positive or negative form upon impact with the atmosphere (1). These findings have elucidated solar wind precipitation dynamics at Mars, and can also be used to monitor the solar wind even when MAVEN is at periapsis (2). In the present study, we focus on a SWIA instrument background signal that has been interpreted as spacecraft/instrument-scattered ions (2). We aim to model and subtract the scattered ion signal from the observations including those of reionized solar wind. We also aim to use the scattered ion signal to track hydrogen ENAs impacting the spacecraft above the reionization altitude. We characterize the energy spectrum and directional scattering function for solar wind scattering off the SWIA aperture structure, the radome and the spacecraft body. We find a broad scattered-ion energy spectrum up to the solar wind energy, displaying increased energy loss and reduced flux with increasing scattering angle, allowing correlations with the solar wind direction, energy, and flux. We develop models that can be used to predict the scattered signal based on the direct solar wind observations or to infer the solar wind properties based on the observed scattered signal. We then investigate deviations to the models when the spacecraft is in the Martian atmosphere and evaluate the plausibility of that these are caused by ENAs. We also perform SIMION modeling of the scattering process and the resulting signal detection by SWIA, to study the results from an instrument point-of-view and evaluate the instrument sensitivity to ENAs. 1. Halekas, J. S., et al. (2015), Geophys. Res. Lett., 42, doi:10.1002/2015GL064693 2. Halekas, J. S., et al. (2017), J. Geophys. Res., 122, doi:10.1002/2016JA023167

Solar system plasma turbulence and intermittency at the maximum and minimum of the solar cycle

NASA Astrophysics Data System (ADS)

Echim, Marius M.

2015-04-01

We report on the analysis of turbulence properties of the solar wind and the planetary magnetosheaths of Venus and Earth at solar maximum (2000-2001) and minimum (1997-1998, 2007-2008) as revealed by Ulysses, Cluster and Venus Express. We provide an overview of the spectral and scaling properties of turbulence during the targeted time periods. A selection of Ulysses data reveals the spectral properties of the "pure" slow and "pure" fast solar wind turbulence, out of the ecliptic, at radial distances ranging between 1.3 and 5.4 AU. Venus Express and Cluster data contribute to the description of the solar wind turbulence at 0.72 AU and respectively 1 AU. The spectral analysis of magnetosheath data from Venus Express and Cluster reveals the properties of turbulence to be compared to solar wind turbulence. The statistical properties of plasma and magnetic field fluctuations exhibit features linked with intermittency revealed as non-Gaussian Probability Distribution Functions (PDFs) and scale dependent kurtosis. PDFs are computed for the solar wind data from Ulysses, Venus Express and Cluster, and complement the analysis based on second order corrrelation function. The same strategy is applied to study the intermittency of the magnetosheath turbulence of Venus and the Earth. The results of our thorough survey of data bases are organized in catalogues available on line: PSD and PDFs results are stored in three solar wind data bases (one for the solar maximum, 1999-2001, two for the solar minimum, 1997-1998 and respectively, 2007-2008), and two planetary databases (one for the solar maximum, 2000-2001, that includes PSDs and PDFs obtained in the terrestrial magnetosheath, and one for the solar minimum, 2007-2008, that includes PSDs and PDFs obtained in the terrestrial and Venus magnetosheaths). As an example of higher order analysis resulting from these results we discuss the similarities and differences between fast and slow wind turbulence and intermittency. We also discuss how the exploitation of data bases produced by the FP7 project STORM contribute to developing a (virtual) laboratory for studying solar system plasma turbulence and intermittency. Research supported by the European FP7 Programme (grant agreement 313038/STORM), and a national grant CNCS -UEFISCDI, project number PN-II-ID-PCE-2012-4-0418.

The evolution of 1 AU equatorial solar wind and its association with the morphology of the heliospheric current sheet from solar cycles 23 to 24

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, L.; Landi, E.; Zurbuchen, T. H.

2014-09-20

The solar wind can be categorized into three types based on its 'freeze-in' temperature (T {sub freeze-in}) in the coronal source: low T {sub freeze-in} wind mostly from coronal holes, high T {sub freeze-in} wind mostly from regions outside of coronal holes, including streamers (helmet streamer and pseudostreamer), active regions, etc., and transient interplanetary coronal mass ejections (ICMEs) usually possessing the hottest T {sub freeze-in}. The global distribution of these three types of wind has been investigated by examining the most effective T {sub freeze-in} indicator, the O{sup 7+}/O{sup 6+} ratio, as measured by the Solar Wind Ion Composition Spectrometermore » on board the Advanced Composition Explorer (ACE) during 1998-2008 by Zhao et al. In this study, we extend the previous investigation to 2011 June, covering the unusual solar minimum between solar cycles 23 and 24 (2007-2010) and the beginning of solar cycle 24. We find that during the entire solar cycle, from the ascending phase of cycle 23 in 1998 to the ascending phase of cycle 24 in 2011, the average fractions of the low O{sup 7+}/O{sup 6+} ratio (LOR) wind, the high O{sup 7+}/O{sup 6+} ratio (HOR) wind, and ICMEs at 1 AU are 50.3%, 39.4%, and 10.3%, respectively; the contributions of the three types of wind evolve with time in very different ways. In addition, we compare the evolution of the HOR wind with two heliospheric current sheet (HCS) parameters, which indicate the latitudinal standard deviation (SD) and the slope (SL) of the HCS on the synoptic Carrington maps at 2.5 solar radii surface. We find that the fraction of HOR wind correlates with SD and SL very well (slightly better with SL than with SD), especially after 2005. This result verifies the link between the production of HOR wind and the morphology of the HCS, implying that at least one of the major sources of the HOR wind must be associated with the HCS.« less

Solar photoionization as a loss mechanism of neutral interstellar hydrogen in interplanetary space

NASA Technical Reports Server (NTRS)

Ogawa, H. S.; Wu, C. Y. Robert; Gangopadhyay, P.; Judge, D. L.

1995-01-01

Two primary loss mechanisms of interstellar neutral hydrogen in interplanetary space are resonance charge exchange ionization with solar wind protons and photoionization by solar EUV radiation. The later process has often been neglected since the average photoionization rate has been estimated to be as much as 5 to 10 times smaller than the charge exchange rate. These factors are based on ionization rates from early measurements of solar EUV and solar wind fluxes. Using revised solar EUV and solar wind fluxes measured near the ecliptic plane we have reinvestigated the ionization rates of interplanetary hydrogen. The result of our analysis indicates that indeed the photoionization rate during solar minimum can be smaller than charge exchange by a factor of 5; however, during solar maximum conditions when solar EUV fluxes are high, and solar wind fluxes are low, photoionization can be over 60% of the charge exchange rate at Earth orbit. To obtain an accurate estimate of the importance of photoionization relative to charge exchange, we have included photoionization from both the ground and metastable states of hydrogen. We find, however, that the photoionization from the metastable state does not contribute significantly to the overall photoionization rate.

The solar wind - Moon interaction discovered by MAP-PACE on KAGUYA

NASA Astrophysics Data System (ADS)

Saito, Y.; Yokota, S.; Tanaka, T.; Asamura, K.; Nishino, M. N.; Yamamoto, T.; Tsunakawa, H.; Shibuya, H.; Shimizu, H.; Takahashi, F.

2009-12-01

Magnetic field And Plasma experiment - Plasma energy Angle and Composition Experiment (MAP-PACE) on KAGUYA (SELENE) completed its ˜1.5-year observation of the low energy charged particles around the Moon. SELENE was successfully launched on 14 September 2007 by H2A launch vehicle from Tanegashima Space Center in Japan. SELENE was inserted into a circular lunar polar orbit of 100km altitude and continued observation for nearly 1.5 years till it impacted the Moon on 10 June 2009. During the last 5 months, the orbit was lowered to ˜50km-altitude between January 2009 and April 2009, and some orbits had further lower perilune altitude of ˜10km after April 2009. The newly observed data showed characteristic ion distributions around the Moon. Besides the solar wind, one of the MAP-PACE sensors MAP-PACE-IMA (Ion Mass Analyzer) discovered four clearly distinguishable ion distributions on the dayside of the Moon: 1) Solar wind ions backscattered at the lunar surface, 2) Solar wind ions reflected by magnetic anomalies on the lunar surface, 3) Ions that are originating from the reflected / backscattered solar wind ions and are pick-up accelerated by the solar wind convection electric field, and 4) Ions originating from the lunar surface / lunar atmosphere. One of the most important discoveries of the ion mass spectrometer (MAP-PACE-IMA) is the first in-situ measurements of the alkali ions originating from the Moon surface / atmosphere. The ions generated on the lunar surface by solar wind sputtering, solar photon stimulated desorption, or micro-meteorite vaporization are accelerated by the solar wind convection electric field and detected by IMA. The mass profiles of these ions show ions including He+, C+, O+, Na+, and K+/Ar+. The heavy ions were also observed when the Moon was in the Earth’s magnetotail where no solar wind ions impinged on the lunar surface. This discovery strongly restricts the possible generation mechanisms of the ionized alkali atmosphere around the Moon. When KAGUYA flew over South Pole Aitken region, where strong magnetic anomalies exist, solar wind ions reflected by magnetic anomalies were observed. These reflected ions had nearly the same energy as the incident solar wind ions, and their flux was more than 10% of the incident solar wind ions. At 100km altitude, when the reflected ions were observed, the simultaneously measured electrons were often heated and the incident solar wind ions were sometimes slightly decelerated. At ~50km altitude, when the reflected ions were observed, proton scattering at the lunar surface clearly disappeared. At ~10km altitude, the interaction between the solar wind ions and the lunar magnetic anomalies was remarkable with clear deceleration of the incident solar wind ions and heating of the reflected ions as well as significant heating of the electrons. These newly discovered plasma signatures around the Moon are the evidences of the smallest magnetosphere ever observed.

On Lunar Exospheric Column Densities and Solar Wind Access Beyond the Terminator from ROSAT Soft X-Ray Observations of Solar Wind Charge Exchange

NASA Technical Reports Server (NTRS)

Collier, Michael R.; Snowden, S. L.; Sarantos, M.; Benna, M.; Carter, J. A.; Cravens, T. E.; Farrell, W. M.; Fatemi, S.; Hills, H. Kent; Hodges, R. R.;

Ionosphere of venus: first observations of the effects of dynamics on the dayside ion composition.

PubMed

Taylor, H A; Brinton, H C; Bauer, S J; Hartle, R E; Cloutier, P A; Michel, F C; Daniell, R E; Donahue, T M; Maehl, R C

1979-02-23

Bennett radio-frequency ion mass spectrometers have returned the first in situ measurements of the Venus dayside ion composition, including evidence of pronounced structural variability resulting from a dynamic interaction with the solar wind. The ionospheric envelope, dominated above 200 kilometers by O(+), responds dramatically to variations in the solar wind pressure, Which is observed to compress the thermal ion distributions from heights as great as 1800 kilometers inward to 280 kilometers. At the thermal ion boundary, or ionopause, the ambient ions are swept away by the solar wind, such that a zone of accelerated suprathermnal plasma is encountered. At higher altitudes, extending outward on some orbits for thousands of kilometers to the bows shock, energetic ion currents are detected, apparently originating from the shocked solar wind plasma. Within the ionosphere, observations of pass-to-pass differences in the ion scale heights are indicative of the effects of ion convection stimlulated by the solar wind interaction.

Beam tracking strategies for studies of kinetic scales in the solar wind with THOR-CSW

NASA Astrophysics Data System (ADS)

De Keyser, Johan; Lavraud, Benoit; Neefs, Eddy; Berkenbosch, Sophie; Anciaux, Michel; Maggiolo, Romain

2016-04-01

Modern plasma spectrometers for monitoring the solar wind attempt to intelligently track the energy and direction of the solar wind beam in order to obtain solar wind velocity distributions more efficiently. Such beam tracking strategies offer some benefits, but also have their limitations and drawbacks. Benefits include an improved resolution and/or a faster velocity distribution function acquisition time. Limitations are due to instrument characteristics that tend to be optimized for a particular range of particle energies and arrival directions. A drawback is the risk to miss an important part of the velocity distribution or to lose track of the beam altogether. A comparison is presented of different beam tracking strategies under consideration for the THOR-CSW instrument in order to highlight a number of design decisions and their impact on the acquired velocity distributions. The gain offered by beam tracking in terms of increased time resolution turns out to be essential for studies of solar wind physics at kinetic scales.

BMSW - Fast Solar Wind Monitor - three years in orbit: Status and prospects

NASA Astrophysics Data System (ADS)

Prech, Lubomir; Zastenker, Georgy; Nemecek, Zdenek; Safrankova, Jana; Vaverka, Jakub; Cermak, Ivo; Chesalin, Lev S.; Gavrilova, Elena

Fast Solar Wind Monitor BMSW is an instrument flown as a part of the PLASMA-F complex onboard the Russian Spektr-R radioastronomical spacecraft. The spacecraft was launched on July 18, 2011. During the COSPAR-2014 Assembly meeting, the instrument is supposed to celebrate three successful years in operation. With a set of 6 Faraday’s cups, the instrument has a unique time resolution --- 0.5--1 s for a full energy spectrum (96 energy steps) and 31~ms for basic solar wind plasma parameters directing the instrument to study of fast solar wind discontinuities including interplanetary shocks, a fast variability of proton and alpha particle parameters, and to study of solar wind turbulence up to the ion kinetic scales. The measurement technique, its implementation, and ground data processing are discussed in the contribution. The performance of the instrument design and electronics are presented. We discuss heritage of this instrument utilized in design of future instruments being prepared for the further projects as Luna-Glob.

Simulating Sources of Superstorm Plasmas

NASA Technical Reports Server (NTRS)

Fok, Mei-Ching

2008-01-01

We evaluated the contributions to magnetospheric pressure (ring current) of the solar wind, polar wind, auroral wind, and plasmaspheric wind, with the surprising result that the main phase pressure is dominated by plasmaspheric protons. We used global simulation fields from the LFM single fluid ideal MHD model. We embedded the Comprehensive Ring Current Model within it, driven by the LFM transpolar potential, and supplied with plasmas at its boundary including solar wind protons, polar wind protons, auroral wind O+, and plasmaspheric protons. We included auroral outflows and acceleration driven by the LFM ionospheric boundary condition, including parallel ion acceleration driven by upward currents. Our plasmasphere model runs within the CRCM and is driven by it. Ionospheric sources were treated using our Global Ion Kinetics code based on full equations of motion. This treatment neglects inertial loading and pressure exerted by the ionospheric plasmas, and will be superceded by multifluid simulations that include those effects. However, these simulations provide new insights into the respective role of ionospheric sources in storm-time magnetospheric dynamics.

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

THE NEW HORIZONS SOLAR WIND AROUND PLUTO (SWAP) OBSERVATIONS OF THE SOLAR WIND FROM 11–33 au

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, H. A.; McComas, D. J.; Valek, P.

The Solar Wind Around Pluto (SWAP) instrument on National Aeronautics and Space Administration's New Horizons Pluto mission has collected solar wind observations en route from Earth to Pluto, and these observations continue beyond Pluto. Few missions have explored the solar wind in the outer heliosphere making this dataset a critical addition to the field. We created a forward model of SWAP count rates, which includes a comprehensive instrument response function based on laboratory and flight calibrations. By fitting the count rates with this model, the proton density (n), speed (V), and temperature (T) parameters are determined. Comparisons between SWAP parametersmore » and both propagated 1 au observations and prior Voyager 2 observations indicate consistency in both the range and mean wind values. These comparisons as well as our additional findings confirm that small and midsized solar wind structures are worn down with increasing distance due to dynamic interaction of parcels of wind with different speed. For instance, the T–V relationship steepens, as the range in V is limited more than the range in T with distance. At times the T–V correlation clearly breaks down beyond 20 au, which may indicate wind currently expanding and cooling may have an elevated T reflecting prior heating and compression in the inner heliosphere. The power of wind parameters at shorter periodicities decreases with distance as the longer periodicities strengthen. The solar rotation periodicity is present in temperature beyond 20 au indicating the observed parcel temperature may reflect not only current heating or cooling, but also heating occurring closer to the Sun.« less

United States Energy Policy: Security Not Independence

DTIC Science & Technology

2013-03-01

the ecosystem. Examples include fish migration considerations for hydropower, birds and bats being killed in wind turbine blades, and many of the U.S...declining oil imports, and domestic energy exploration will remain American priorities. He went on to list wind , solar, clean coal, and biofuels as...crops - Winds not constant or reliable -Impact to ecosystem -Unsightly addition to landscape Solar16 -Renewable and clean -Minimal impact to

Solar system plasma Turbulence: Observations, inteRmittency and Multifractals

NASA Astrophysics Data System (ADS)

Echim, Marius M.

2016-04-01

The FP7 project STORM is funded by the European Commission to "add value to existing data bases through a more comprehensive interpretation". STORM targets plasma and magnetic field databases collected in the solar wind (Ulysses and also some planetary missions), planetary magnetospheres (Venus Express, Cluster, a few orbits from Cassini), cometary magnetosheaths (e.g. Haley from Giotto observations). The project applies the same package of analysis methods on geomagnetic field observations from ground and on derived indices (e.g. AE, AL, AU, SYM-H). The analysis strategy adopted in STORM is built on the principle of increasing complexity, from lower (like, e.g., the Power Spectral Density - PSD) to higher order analyses (the Probability Distribution Functions - PDFs, Structure Functions - SFs, Fractals and Multifractals - MFs). Therefore STORM targets not only the spectral behavior of turbulent fluctuations but also their topology and scale behavior inferred from advanced mathematical algorithms and geometrical-like analogs. STORM started in January 2013 and ended in December 2015. We will report on a selection of scientific and technical achievements and will highlight: (1) the radial evolution of solar wind turbulence and intermittency based on Ulysses data with some contributions from Venus Express and Cluster; (2) comparative study of fast and slow wind turbulence and intermittency at solar minimum; (3) comparative study of the planetary response (Venus and Earth magnetosheaths) to turbulent solar wind; (4) the critical behavior of geomagnetic fluctuations and indices; (5) an integrated library for non-linear analysis of time series that includes all the approaches adopted in STORM to investigate solar system plasma turbulence. STORM delivers an unprecedented volume of analysed data for turbulence. The project made indeed a systematic survey, orbit by orbit, of data available from ESA repositories and Principal Investigators and provides results ordered as a function of the targeted system (solar wind/magnetospheres/geomagnetic indices), solar cycle phase (minimum versus maximum), type of result (PSDs, PDFs, Multifractals). The results catalogues, available online from http://www.storm-fp7.eu, include 4094 PSD spectra, 9566 PDFs and 15633 multifractal spectra (from partition function and respectively Rank Ordered (ROMA) formalisms). These results are obtained at solar maximum (2001-2002, both in the solar wind and the terrestrial magnetosheath) and solar minimum (1997-1998 in the solar wind, 2007-2008 in the solar wind, Venus and Earth magnetosheath and selected regions of the magnetosphere). Research supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 313038/STORM.

Solar wind radiation damage effects in lunar material

NASA Technical Reports Server (NTRS)

Hapke, B.; Cohen, A. J.; Cassidy, W. A.

1971-01-01

The research on solar wind radiation damage and other effects in lunar samples which was conducted to understand the optical properties of lunar materials is reported. Papers presented include: solar radiation effects in lunar samples, albedo of the moon, radiation effects in lunar crystalline rocks, valence states of 3rd transition elements in Apollo 11 and 12 rocks, and trace ferric iron in lunar and meteoritic titanaugites.

PHOTOIONIZATION IN THE SOLAR WIND

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landi, E.; Lepri, S. T., E-mail: elandi@umich.edu

2015-10-20

In this work we investigate the effects of photoionization on the charge state composition of the solar wind. Using measured solar EUV and X-ray irradiance, the Michigan Ionization Code and a model for the fast and slow solar wind, we calculate the evolution of the charge state distribution of He, C, N, O, Ne, Mg, Si, S, and Fe with and without including photoionization for both types of wind. We find that the solar radiation has significant effects on the charge state distribution of C, N, and O, causing the ionization levels of these elements to be higher than withoutmore » photoionization; differences are largest for oxygen. The ions commonly observed for elements heavier than O are much less affected, except in ICMEs where Fe ions more ionized than 16+ can also be affected by the solar radiation. We also show that the commonly used O{sup 7+}/O{sup 6+} density ratio is the most sensitive to photoionization; this sensitivity also causes the value of this ratio to depend on the phase of the solar cycle. We show that the O{sup 7+}/O{sup 6+} ratio needs to be used with caution for solar wind classification and coronal temperature estimates, and recommend the C{sup 6+}/C{sup 4+} ratio for these purposes.« less

Markets to Facilitate Wind and Solar Energy Integration in the Bulk Power Supply: An IEA Task 25 Collaboration; Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milligan, M.; Holttinen, H.; Soder, L.

2012-09-01

Wind and solar power will give rise to challenges in electricity markets regarding flexibility, capacity adequacy, and the participation of wind and solar generators to markets. Large amounts of wind power will have impacts on bulk power system markets and electricity prices. If the markets respond to increased wind power by increasing investments in low-capital, high-cost or marginal-cost power, the average price may remain in the same range. However, experiences so far from Denmark, Germany, Spain, and Ireland are such that the average market prices have decreased because of wind power. This reduction may result in additional revenue insufficiency, whichmore » may be corrected with a capacity market, yet capacity markets are difficult to design. However, the flexibility attributes of the capacity also need to be considered. Markets facilitating wind and solar integration will include possibilities for trading close to delivery (either by shorter gate closure times or intraday markets). Time steps chosen for markets can enable more flexibility to be assessed. Experience from 5- and 10-minute markets has been encouraging.« less

77 FR 61597 - Avalon Wind, LLC; Avalon Wind 2, LLC; Catalina Solar, LLC; Catalina Solar 2, LLC; Pacific Wind...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-10

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL12-109-000] Avalon Wind, LLC; Avalon Wind 2, LLC; Catalina Solar, LLC; Catalina Solar 2, LLC; Pacific Wind Lessee, LLC; Pacific Wind 2, LLC; Valentine Solar, LLC; EDF Renewable Development, Inc.; Notice of Petition for Declaratory...

Saptio-temporal complementarity of wind and solar power in India

NASA Astrophysics Data System (ADS)

Lolla, Savita; Baidya Roy, Somnath; Chowdhury, Sourangshu

2015-04-01

Wind and solar power are likely to be a part of the solution to the climate change problem. That is why they feature prominently in the energy policies of all industrial economies including India. One of the major hindrances that is preventing an explosive growth of wind and solar energy is the issue of intermittency. This is a major problem because in a rapidly moving economy, energy production must match the patterns of energy demand. Moreover, sudden increase and decrease in energy supply may destabilize the power grids leading to disruptions in power supply. In this work we explore if the patterns of variability in wind and solar energy availability can offset each other so that a constant supply can be guaranteed. As a first step, this work focuses on seasonal-scale variability for each of the 5 regional power transmission grids in India. Communication within each grid is better than communication between grids. Hence, it is assumed that the grids can switch sources relatively easily. Wind and solar resources are estimated using the MERRA Reanalysis data for the 1979-2013 period. Solar resources are calculated with a 20% conversion efficiency. Wind resources are estimated using a 2 MW turbine power curve. Total resources are obtained by optimizing location and number of wind/solar energy farms. Preliminary results show that the southern and western grids are more appropriate for cogeneration than the other grids. Many studies on wind-solar cogeneration have focused on temporal complementarity at local scale. However, this is one of the first studies to explore spatial complementarity over regional scales. This project may help accelerate renewable energy penetration in India by identifying regional grid(s) where the renewable energy intermittency problem can be minimized.

The singing comet 67P: utilizing fully kinetic simulations to study its interaction with the solar wind plasma

NASA Astrophysics Data System (ADS)

Deca, J.; Divin, A. V.; Horanyi, M.; Henri, P.

2016-12-01

We present preliminary results of the first 3-D fully kinetic and electromagnetic simulations of the solar wind interaction with 67P/Churyumov-Gerasimenko at 3 AU, before the comet transitions into its high-activity phase. We focus on the global cometary environment and the electron-kinetic activity of the interaction. In addition to the background solar wind plasma flow, our model includes also plasma-driven ionization of cometary neutrals and collisional effects. We approximate mass loading of cold cometary oxygen and hydrogen using a hyperbolic relation with distance to the comet. We consider two primary cases: a weak outgassing comet (with the peak ion density 10x the solar wind density) and a moderately outgassing comet (with the peak ion density 50x the solar wind density). The weak comet is characterized by the formation of a narrow region containing a compressed solar wind (the density of the solar wind ion population is 3x the value far upstream of the comet) and a magnetic barrier ( 2x to 4x the interplanetary magnetic field). Blobs of plasma are detached continuously from this sheath region. Standing electromagnetic waves are excited in the cometary wake due to a strong anisotropy in the plasma pressure, as the density and the magnetic field magnitude are anti-correlated.The moderate mass-loading case shows more dynamics at the dayside region. The stagnation of the solar wind flow is accompanied by the formation of elongated density stripes, indicating the presence of a Rayleigh-Taylor instability. These density cavities are elongated in the direction of the magnetic field and encompass the dayside ionopause. To conclude, we believe that our results provide vital information to disentangle the observations made by the Rosetta spacecraft and compose a global solar wind - comet interaction model.

Number density structures in the inner heliosphere

NASA Astrophysics Data System (ADS)

Stansby, D.; Horbury, T. S.

2018-06-01

Aims: The origins and generation mechanisms of the slow solar wind are still unclear. Part of the slow solar wind is populated by number density structures, discrete patches of increased number density that are frozen in to and move with the bulk solar wind. In this paper we aimed to provide the first in-situ statistical study of number density structures in the inner heliosphere. Methods: We reprocessed in-situ ion distribution functions measured by Helios in the inner heliosphere to provide a new reliable set of proton plasma moments for the entire mission. From this new data set we looked for number density structures measured within 0.5 AU of the Sun and studied their properties. Results: We identified 140 discrete areas of enhanced number density. The structures occurred exclusively in the slow solar wind and spanned a wide range of length scales from 50 Mm to 2000 Mm, which includes smaller scales than have been previously observed. They were also consistently denser and hotter that the surrounding plasma, but had lower magnetic field strengths, and therefore remained in pressure balance. Conclusions: Our observations show that these structures are present in the slow solar wind at a wide range of scales, some of which are too small to be detected by remote sensing instruments. These structures are rare, accounting for only 1% of the slow solar wind measured by Helios, and are not a significant contribution to the mass flux of the solar wind.

Increasing the percentage of renewable energy in the Southwestern United States

USDA-ARS?s Scientific Manuscript database

Combining the output of wind farms with that of Concentrating Solar Power (CSP) plants (including a heat storage system) resulted in a substantial percentage (40%) of the total utility electrical generation in the Southwestern United States being met by renewable energy. Using wind and solar resourc...

On the Origins of the Intercorrelations Between Solar Wind Variables

NASA Astrophysics Data System (ADS)

Borovsky, Joseph E.

2018-01-01

It is well known that the time variations of the diverse solar wind variables at 1 AU (e.g., solar wind speed, density, proton temperature, electron temperature, magnetic field strength, specific entropy, heavy-ion charge-state densities, and electron strahl intensity) are highly intercorrelated with each other. In correlation studies of the driving of the Earth's magnetosphere-ionosphere-thermosphere system by the solar wind, these solar wind intercorrelations make determining cause and effect very difficult. In this report analyses of solar wind spacecraft measurements and compressible-fluid computer simulations are used to study the origins of the solar wind intercorrelations. Two causes are found: (1) synchronized changes in the values of the solar wind variables as the plasma types of the solar wind are switched by solar rotation and (2) dynamic interactions (compressions and rarefactions) in the solar wind between the Sun and the Earth. These findings provide an incremental increase in the understanding of how the Sun-Earth system operates.

Solar cycle dependence of the heliospheric shape deduced from a global MHD simulation of the interaction process between a nonuniform time-dependent solar wind and the local interstellar medium

NASA Astrophysics Data System (ADS)

Tanaka, T.; Washimi, H.

1999-06-01

The global structure of the solar wind/very local interstellar medium interaction is studied from a fully three-dimensional time-dependent magnetohydrodynamic model, in which the solar wind speed increases from 400 to 800 km/s in going from the ecliptic to pole and the heliolatitude of the low-high-speed boundary changes from 30° to 80° in going from the solar minimum to solar maximum. In addition, the interplanetary magnetic field (IMF) changes its polarity at the solar maximum. As a whole, the shapes of the terminal shock (TS) and heliopause (HP) are elongated along the solar polar axis owing to a high solar wind ram pressure over the poles. In the ecliptic plane, the heliospheric structure changes little throughout a solar cycle. The TS in this plane shows a characteristic bullet-shaped structure. In the polar plane, on the other hand, the shape of the TS exhibits many specific structures according to the stage of the solar cycle. These structures include the polygonal configuration of the polar TS seen around the solar minimum, the mesa- and terrace-shaped TSs in the high- and low-speed solar wind regions seen around the ascending phase, and the chimney-shaped TS in the high-speed solar wind region seen around the solar maximum. These structures are formed from different combinations of right-angle shock, oblique shock, and steep oblique shock so as to transport the heliosheath plasma most efficiently toward the heliotail (HT). In the HT, the hot and weakly-magnetized plasma from the high-heliolatitude TS invades as far as the ecliptic plane. A weakly time-dependent recirculation flow in the HT is a manifestation of invading flow. Distributions of magnetic field in the HT, which are a pile-up of the compressed MF over several solar cycles, are modified by the flow from high-heliolatitude.

Simulation and optimum design of hybrid solar-wind and solar-wind-diesel power generation systems

NASA Astrophysics Data System (ADS)

Zhou, Wei

Solar and wind energy systems are considered as promising power generating sources due to its availability and topological advantages in local power generations. However, a drawback, common to solar and wind options, is their unpredictable nature and dependence on weather changes, both of these energy systems would have to be oversized to make them completely reliable. Fortunately, the problems caused by variable nature of these resources can be partially overcome by integrating these two resources in a proper combination to form a hybrid system. However, with the increased complexity in comparison with single energy systems, optimum design of hybrid system becomes more complicated. In order to efficiently and economically utilize the renewable energy resources, one optimal sizing method is necessary. This thesis developed an optimal sizing method to find the global optimum configuration of stand-alone hybrid (both solar-wind and solar-wind-diesel) power generation systems. By using Genetic Algorithm (GA), the optimal sizing method was developed to calculate the system optimum configuration which offers to guarantee the lowest investment with full use of the PV array, wind turbine and battery bank. For the hybrid solar-wind system, the optimal sizing method is developed based on the Loss of Power Supply Probability (LPSP) and the Annualized Cost of System (ACS) concepts. The optimization procedure aims to find the configuration that yields the best compromise between the two considered objectives: LPSP and ACS. The decision variables, which need to be optimized in the optimization process, are the PV module capacity, wind turbine capacity, battery capacity, PV module slope angle and wind turbine installation height. For the hybrid solar-wind-diesel system, minimization of the system cost is achieved not only by selecting an appropriate system configuration, but also by finding a suitable control strategy (starting and stopping point) of the diesel generator. The optimal sizing method was developed to find the system optimum configuration and settings that can achieve the custom-required Renewable Energy Fraction (fRE) of the system with minimum Annualized Cost of System (ACS). Du to the need for optimum design of the hybrid systems, an analysis of local weather conditions (solar radiation and wind speed) was carried out for the potential installation site, and mathematical simulation of the hybrid systems' components was also carried out including PV array, wind turbine and battery bank. By statistically analyzing the long-term hourly solar and wind speed data, Hong Kong area is found to have favorite solar and wind power resources compared with other areas, which validates the practical applications in Hong Kong and Guangdong area. Simulation of PV array performance includes three main parts: modeling of the maximum power output of the PV array, calculation of the total solar radiation on any tilted surface with any orientations, and PV module temperature predictions. Five parameters are introduced to account for the complex dependence of PV array performance upon solar radiation intensities and PV module temperatures. The developed simulation model was validated by using the field-measured data from one existing building-integrated photovoltaic system (BIPV) in Hong Kong, and good simulation performance of the model was achieved. Lead-acid batteries used in hybrid systems operate under very specific conditions, which often cause difficulties to predict when energy will be extracted from or supplied to the battery. In this thesis, the lead-acid battery performance is simulated by three different characteristics: battery state of charge (SOC), battery floating charge voltage and the expected battery lifetime. Good agreements were found between the predicted values and the field-measured data of a hybrid solar-wind project. At last, one 19.8kW hybrid solar-wind power generation project, designed by the optimal sizing method and set up to supply power for a telecommunication relay station on a remote island of Guangdong province, was studied. Simulation and experimental results about the operating performances and characteristics of the hybrid solar-wind project have demonstrated the feasibility and accuracy of the recommended optimal sizing method developed in this thesis.

Stellar Ablation of Planetary Atmospheres

NASA Technical Reports Server (NTRS)

Moore, Thomas E.; Horwitz, J. L.

2007-01-01

We review observations and theories of the solar ablation of planetary atmospheres, focusing on the terrestrial case where a large magnetosphere holds off the solar wind, so that there is little direct atmospheric impact, but also couples the solar wind electromagnetically to the auroral zones. We consider the photothermal escape flows known as the polar wind or refilling flows, the enhanced mass flux escape flows that result from localized solar wind energy dissipation in the auroral zones, and the resultant enhanced neutral atom escape flows. We term these latter two escape flows the "auroral wind." We review observations and theories of the heating and acceleration of auroral winds, including energy inputs from precipitating particles, electromagnetic energy flux at magnetohydrodynamic and plasma wave frequencies, and acceleration by parallel electric fields and by convection pickup processes also known as "centrifugal acceleration." We consider also the global circulation of ionospheric plasmas within the magnetosphere, their participation in magnetospheric disturbances as absorbers of momentum and energy, and their ultimate loss from the magnetosphere into the downstream solar wind, loading reconnection processes that occur at high altitudes near the magnetospheric boundaries. We consider the role of planetary magnetization and the accumulating evidence of stellar ablation of extrasolar planetary atmospheres. Finally, we suggest and discuss future needs for both the theory and observation of the planetary ionospheres and their role in solar wind interactions, to achieve the generality required for a predictive science of the coupling of stellar and planetary atmospheres over the full range of possible conditions.

Turbulence-driven Coronal Heating and Improvements to Empirical Forecasting of the Solar Wind

NASA Astrophysics Data System (ADS)

Woolsey, Lauren N.; Cranmer, Steven R.

2014-06-01

Forecasting models of the solar wind often rely on simple parameterizations of the magnetic field that ignore the effects of the full magnetic field geometry. In this paper, we present the results of two solar wind prediction models that consider the full magnetic field profile and include the effects of Alfvén waves on coronal heating and wind acceleration. The one-dimensional magnetohydrodynamic code ZEPHYR self-consistently finds solar wind solutions without the need for empirical heating functions. Another one-dimensional code, introduced in this paper (The Efficient Modified-Parker-Equation-Solving Tool, TEMPEST), can act as a smaller, stand-alone code for use in forecasting pipelines. TEMPEST is written in Python and will become a publicly available library of functions that is easy to adapt and expand. We discuss important relations between the magnetic field profile and properties of the solar wind that can be used to independently validate prediction models. ZEPHYR provides the foundation and calibration for TEMPEST, and ultimately we will use these models to predict observations and explain space weather created by the bulk solar wind. We are able to reproduce with both models the general anticorrelation seen in comparisons of observed wind speed at 1 AU and the flux tube expansion factor. There is significantly less spread than comparing the results of the two models than between ZEPHYR and a traditional flux tube expansion relation. We suggest that the new code, TEMPEST, will become a valuable tool in the forecasting of space weather.

Plasmas in the outer heliosphere

NASA Technical Reports Server (NTRS)

Belcher, J. W.; Richardson, J. D.; Lazarus, A. J.; Gazis, P. R.; Barnes, A.

1995-01-01

We review the observed properties of the solar wind in the outer heliosphere, including observations from Voyager and the Pioneers, as well as from inner heliospheric probes as appropriate. These observations are crucial to modeling of the heliosphere and its interactions with the interstellar medium, since the wind ram pressure and its temporal variations are important in understanding the distance to the termination shock and heliopause and how those boundaries might vary in time. We focus on results since Solar Wind 7. Among the issues we will discuss are: (1) the time scales for and statistical properties of variations in the ram pressure in the outer heliosphere, and how those variations might affect the morphology of the heliospheric/interstellar medium interface; (2) the question of possible solar wind slowing in the outer heliosphere due to the pick-up of interstellar ions; (3) the issue of whether there is bulk heating of the solar wind associated either with interstellar ion pick-up or with continued heating due to stream-stream interactions; (4) evidence for latitudinal variations in solar wind properties; and (5) the 1.3 year periodicities apparent in the outer heliosphere, and the close correspondence with similar variations seen with inner heliospheric probes.

Genesis Radiation Environment

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Altstatt, Richard L.; Skipworth, William C.

2007-01-01

The Genesis spacecraft launched on 8 August 2001 sampled solar wind environments at L1 from 2001 to 2004. After the Science Capsule door was opened, numerous foils and samples were exposed to the various solar wind environments during periods including slow solar wind from the streamer belts, fast solar wind flows from coronal holes, and coronal mass ejections. The Survey and Examination of Eroded Returned Surfaces (SEERS) program led by NASA's Space Environments and Effects program had initiated access for the space materials community to the remaining Science Capsule hardware after the science samples had been removed for evaluation of materials exposure to the space environment. This presentation will describe the process used to generate a reference radiation Genesis Radiation Environment developed for the SEERS program for use by the materials science community in their analyses of the Genesis hardware.

Wave-Particle Interactions As a Driving Mechanism for the Solar Wind

NASA Technical Reports Server (NTRS)

Wagner, William J.

2004-01-01

Our research has been focusing on a highly experimentally relevant issue: intermittency of the fluctuating fields in outflowing plasmas. We have contributed to both the theoretical and experimental research of the topic. In particular, we have developed a theoretical model and data analyzing programs to examine the issue of intermittency in space plasma outflows, including the solar wind. As fluctuating electric fields in the solar wind are likely to provide a heating and acceleration mechanism for the ions, our studies of the intermittency in turbulence in space plasma outflows help us toward achieving the goal of comparing major physical mechanisms that contribute to the driving of the fast solar wind. Our new theoretical model extends the utilities of our global hybrid model, which has allowed us to follow the kinetic evolution of the particle distributions along an inhomogeneous field line while the particles are subjected to various physical mechanisms. The physical effects that were considered in the global hybrid model included wave-particle interactions, an ambipolar electric field that was consistent with the particle distributions themselves, and Coulomb collisions. With an earlier version of the global hybrid model, we examined the overall impact on the solar wind flow due to the combination of these physical effects. In particular, we studied the combined effects of two major mechanisms that had been proposed as the drivers of the fast solar wind: (1) velocity filtration effect due to suprathermal electrons; (2) ion cyclotron resonance. Since the approval of this research grant, we have updated the model such that the effects due to these two driving mechanisms can be examined separately, thereby allowing us to compare their contributions to the acceleration of the solar wind. In the next section, we shall demonstrate that the velocity filtration effect is rather insignificant in comparison with that due to ion cyclotron resonance.

Renewable Energy Zones for the Africa Clean Energy Corridor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Grace C.; Deshmukh, Ranjit; Ndhlukula, Kudakwashe

Multi-criteria Analysis for Planning Renewable Energy (MapRE) is a study approach developed by the Lawrence Berkeley National Laboratory with the support of the International Renewable Energy Agency (IRENA). The approach combines geospatial, statistical, energy engineering, and economic methods to comprehensively identify and value high-quality wind, solar PV, and solar CSP resources for grid integration based on techno-economic criteria, generation profiles (for wind), and socio-environmental impacts. The Renewable Energy Zones for the Africa Clean Energy Corridor study sought to identify and comprehensively value high-quality wind, solar photovoltaic (PV), and concentrating solar power (CSP) resources in 21 countries in the East andmore » Southern Africa Power Pools to support the prioritization of areas for development through a multi-criteria planning process. These countries include Angola, Botswana, Burundi, Djibouti, Democratic Republic of Congo, Egypt, Ethiopia, Kenya, Lesotho, Libya, Malawi, Mozambique, Namibia, Rwanda, South Africa, Sudan, Swaziland, Tanzania, Uganda, Zambia, and Zimbabwe. The study includes the methodology and the key results including renewable energy potential for each region.« less

The Solar Connections Observatory for Planetary Environments (SCOPE):

NASA Astrophysics Data System (ADS)

Oliversen, R.; Harris, W.; Ballester, G.; Bougher, S.; Broadfoot, L.; Combi, M.; Cravens, T.; Gombosi, T.; Herbert, F.; Joseph, C.; Kozyra, J.; Limaye, S.; Morgenthaler, J.; Paxton, L.; Roesler, F.; Sandel, W.; Ben Jaffel, L.

2001-12-01

The NASA Sun-Earth Connection theme roadmap calls for comparative study of how the planets and local interstellar medium (LISM) interact with and respond to changes in the solar wind and UV radiation field. Each planet interaction is unique and defined by solar input and local conditions of magnetic field strength and orientation, rotation rate, heliocentric distance, internal plasma, and ionospheric conductivity and circulation. Because the different elements of the environment respond to external and internal influences that are variable on many temporal and spatial scales, the study of a planetary system requires simultaneous understanding of the solar wind and diagnostics of the sun-planet interaction including auroral intensity and variation, upper atmospheric circulation and composition, and the distribution of neutrals and plasmas near the planet. The Solar Connections Observatory for Planetary Environments (SCOPE) is a mission to study Solar interactions from the level of planetary upper atmospheres to the heliopause. SCOPE consists of a binocular EUV/FUV telescope that provides high spatial resolution imaging, broadband spectro-imaging, and high-resolution H Ly-alpha line spectroscopy between 55-290 nm. SCOPE will study planetary environments as examples of the solar connection and map the distribution of interplanetary H and the interaction of LISM plasma with the solar wind at the heliopause. A key to the SCOPE approach is to include Earth in its research objectives. SCOPE will monitor terrestrial auroral energy deposition and leverage local measurements of the solar wind and propagation models to derive the expected conditions at Superior planets that will be observed in annual opposition campaigns. This will permit direct comparison of planetary and terrestrial responses to the same solar wind stream. Using a combination of observations and MHD models, SCOPE will isolate the different controlling parameters in each planet system and gain insight into the underlying physical processes that define the solar connection.

Galactic cosmic-ray mediation of a spherical solar wind flow. 1: The steady state cold gas hydrodynamical approximation

NASA Technical Reports Server (NTRS)

Le Roux, J. A.; Ptuskin, V. S.

1995-01-01

Realistic models of the outer heliosphere should consider that the interstellar cosmic-ray pressure becomes comparable to pressures in the solar wind at distances more than 100 AU from the Sun. The cosmic-ray pressure dynamically affects solar wind flow through deceleration. This effect, which occurs over a scale length of the order of the effective diffusion length at large radial distances, has important implications for cosmic-ray modulation and acceleration. As a first step toward solution of this nonlinear problem, a steady state numerical model was developed for a relatively cold spherical solar wind flow which encounters the confining isotropic pressure of the surrounding Galactic medium. This pressure is assumed to be dominated by energetic particles (Galactic cosmic rays). The system of equations, which are solved self-consistently, includes the relevant hydrodynamical equations for the solar wind flow and the spherical cosmic-ray transport equation. To avoid the closure parameter problem of the two-fluid model, the latter equation is solved for the energy-dependent cosmic-ray distribution function.

Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadid, L. Z.; Sahraoui, F.; Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr

2017-03-20

Estimation of the energy cascade rate in the inertial range of solar wind turbulence has been done so far mostly within incompressible magnetohydrodynamics (MHD) theory. Here, we go beyond that approximation to include plasma compressibility using a reduced form of a recently derived exact law for compressible, isothermal MHD turbulence. Using in situ data from the THEMIS / ARTEMIS spacecraft in the fast and slow solar wind, we investigate in detail the role of the compressible fluctuations in modifying the energy cascade rate with respect to the prediction of the incompressible MHD model. In particular, we found that the energymore » cascade rate (1) is amplified particularly in the slow solar wind; (2) exhibits weaker fluctuations in spatial scales, which leads to a broader inertial range than the previous reported ones; (3) has a power-law scaling with the turbulent Mach number; (4) has a lower level of spatial anisotropy. Other features of solar wind turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models.« less

Anorthite sputtering by H + and Ar q+ (q = 1-9) at solar wind velocities

DOE PAGES

Hijazi, Hussein Dib; Bannister, Mark E.; Meyer, III, Harry M.; ...

2014-10-16

Here, we report sputtering measurements of anorthite-like material, taken to be representative of soils found in the lunar highlands, impacted by singly and multicharged ions representative of the solar wind. The ions investigated include protons, as well as singly and multicharged Ar ions (as proxies for the nonreactive heavy solar wind constituents), in the charge state range +1 to +9, at fixed solar wind-relevant impact velocities of 165 and 310 km/s (0.25 keV/amu and 0.5 keV/amu). A quartz microbalance approach (QCM) for determination of total sputtering yields was used. The goal of the measurements was to determine the sputtering contributionmore » of the heavy, multicharged minority solar wind constituents in comparison to that due to the dominant H + fraction. The QCM results show a yield increase of a factor of about 80 for Ar + versus H + sputtering and an enhancement by a factor of 1.67 between Ar 9+ and Ar +, which is a clear indication of a potential sputtering effect.« less

Kinetic and Potential Sputtering of Lunar Regolith: Contribution of Solar-Wind Heavy Ions

NASA Technical Reports Server (NTRS)

Meyer, F. W.; Harris, P. R.; Meyer, H. M., III; Hijiazi, H.; Barghouty, A. F.

2013-01-01

Sputtering of lunar regolith by protons as well as solar-wind heavy ions is considered. From preliminary measurements of H+, Ar+1, Ar+6 and Ar+9 ion sputtering of JSC-1A AGGL lunar regolith simulant at solar wind velocities, and TRIM simulations of kinetic sputtering yields, the relative contributions of kinetic and potential sputtering contributions are estimated. An 80-fold enhancement of oxygen sputtering by Ar+ over same-velocity H+, and an additional x2 increase for Ar+9 over same-velocity Ar+ was measured. This enhancement persisted to the maximum fluences investigated is approximately 1016/cm (exp2). Modeling studies including the enhanced oxygen ejection by potential sputtering due to the minority heavy ion multicharged ion solar wind component, and the kinetic sputtering contribution of all solar wind constituents, as determined from TRIM sputtering simulations, indicate an overall 35% reduction of near-surface oxygen abundance. XPS analyses of simulant samples exposed to singly and multicharged Ar ions show the characteristic signature of reduced (metallic) Fe, consistent with the preferential ejection of oxygen atoms that can occur in potential sputtering of some metal oxides.

MIT solar wind plasma data from Explorer 33 and Explorer 35: July 1966 to September 1970

NASA Technical Reports Server (NTRS)

Howe, H.; Binsack, J.; Wang, C.; Clapp, E.

1971-01-01

The plasma experiments on Explorer 33 and Explorer 35 have yielded large amounts of solar wind data. This report gives a brief review of the method used to obtain the data, provides a description of the plasma parameters, and describes in detail the format of the plots and tapes which are available from the Data Center. Hourly average plots of the data are included at the end of the report. From these plots, the availability and interest of the solar wind data for any period of time may be determined.

India RE Grid Integration Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Jaquelin M

The use of renewable energy (RE) sources, primarily wind and solar generation, is poised to grow significantly within the Indian power system. The Government of India has established a target of 175 gigawatts (GW) of installed RE capacity by 2022, including 60 GW of wind and 100 GW of solar, up from 29 GW wind and 9 GW solar at the beginning of 2017. Thanks to advanced weather and power system modeling made for this project, the study team is able to explore operational impacts of meeting India's RE targets and identify actions that may be favorable for integration.

Venus general atmosphere circulation described by Pioneer

NASA Technical Reports Server (NTRS)

1981-01-01

The predominant weather pattern for Venus is described. Wind directions and wind velocities are given. Possible driving forces of the winds are presented and include solar heating, planetary rotation, and the greenhouse effect.

Overview of the HELCATS project

NASA Astrophysics Data System (ADS)

Harrison, Richard; Davies, Jackie; Perry, Chris; Moestl, Christian; Rouillard, Alexis; Bothmer, Volker; Rodriguez, Luciano; Eastwood, Jonathan; Kilpua, Emilia; Gallagher, Peter; Odstrcil, Dusan

2017-04-01

Understanding solar wind evolution is fundamental to advancing our knowledge of energy and mass transport in the solar system, whilst also being crucial to space weather and its prediction. The advent of truly wide-angle heliospheric imaging has revolutionised the study of solar wind evolution, by enabling direct and continuous observation of both transient and background components of the solar wind as they propagate from the Sun to 1 AU and beyond. The EU-funded FP7 Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) project combines European expertise in heliospheric imaging, built up over the last decade in particular through lead involvement in NASA's STEREO mission, with expertise in solar and coronal imaging as well as the interpretation of in-situ and radio diagnostic measurements of solar wind phenomena. HELCATS involves: (1) cataloguing of transient (coronal mass ejections) and background (stream/corotating interaction regions) solar wind structures observed by the STEREO/Heliospheric Imagers, including estimates of their kinematic properties based on a variety of modelling techniques; (2) verifying these kinematic properties through comparison with solar source observations and in-situ measurements at multiple points throughout the heliosphere; (3) assessing the potential for initialising numerical models based on the derived kinematic properties of transient and background solar wind components; (4) assessing the complementarity of radio observations (Type II radio bursts and interplanetary scintillation) in the detection and analysis of heliospheric structure in combination with heliospheric imaging observations. We provide an overview of the achievements of the HELCATS project, as it reaches its conclusion, and present selected results that seek to illustrate the value and legacy of this unprecedented, coordinated study of structures in the heliosphere.

Transient behavior of flare-associated solar wind. II - Gas dynamics in a nonradial open field region

NASA Technical Reports Server (NTRS)

Nagai, F.

1984-01-01

Transient behavior of flare-associated solar wind in the nonradial open field region is numerically investigated, taking into account the thermal and dynamical coupling between the chromosphere and the corona. A realistic steady solar wind is constructed which passes through the inner X-type critical point in the rapidly diverging region. The wind speed shows a local maximum at the middle, O-type, critical point. The wind's density and pressure distributions decrease abruptly in the rapidly diverging region of the flow tube. The transient behavior of the wind following flare energy deposition includes ascending and descending conduction fronts. Thermal instability occurs in the lower corona, and ascending material flows out through the throat after the flare energy input ceases. A local density distribution peak is generated at the shock front due to the pressure deficit just behind the shock front.

Lunar Solar Origins Exploration (LunaSOX)

NASA Technical Reports Server (NTRS)

Cooper, John F.; King, Joseph H.; Papitashvili, Natasha; Lipatov, Alexander S.; Sittler, Edward C.; Hartle, Richard E.

2011-01-01

The Moon offers a unique vantage point from which to investigate the Sun and its interaction via the solar wind magnetic fields, plasma, and energetic particles with the geospace system including the Moon itself. The lunar surface and exosphere provide in part a record of solar coronal plasma material input and resultant space weathering over billions of years. The structure and dynamics of solar wind interactions with the Moon provide an accessible near-Earth laboratory environment for study of general solar wind interactions with the vast multitude of airless asteroidal bodies of the inner solar system. Spacecraft in lunar orbit have the often simultaneous opportunity, except when in the Earth's magnetosphere, to make in-situ compositional measurements of the solar wind plasma and to carry out remote observations from the Moon of the solar corona, potentially enabled by lunar limb occultation of the solar disk. The LunaSOX project at NASA Goddard Space Flight Center is addressing these heliophysical science objectives from and of the Moon with support from NASA's Lunar Advanced Science and Exploration Research (LASER) program: (1) specify history of solar wind parameters at and sunward of the Moon through enhanced access (http://lunasox.gsfc.nasa.gov/) to legacy and operational mission data products from the Apollo era to the present, (2) model field and plasma interactions with the lunar surface, exosphere, and wake, as constrained by the available data, through hybrid kinetic code simulations, and (3) advance mission concepts for heliophysics from and of the Moon.

Keeping the Future Bright: Department of Defense (DOD) Sustainable Energy Strategy for Installations

DTIC Science & Technology

2016-04-04

sustainable energy included renewable energy sources, such as hydroelectricity, solar energy, wind energy, wave power, geothermal energy, bioenergy, tidal...energy, including bioftiel and other alternative sources (wind. solar, and geothermal ).27 The SECNAV made security and independence the two energy...Navy’s China Lake geothermal power plant in California is DOD’s largest renewable energy project supplying nearly half of DOD’s renewable energy

NSF presentation. [summary on energy conversion research program

NASA Technical Reports Server (NTRS)

Morse, F. H.

1973-01-01

Wind energy conversion research is considered in the framework of the national energy problem. Research and development efforts for the practical application of solar energy -- including wind energy -- as alternative energy supplies are assessed in: (1) Heating and cooling of buildings; (2) photovoltaic energy conversion; (3) solar thermal energy conversion; (4) wind energy conversion; (5) ocean thermal energy conversion; (6) photosynthetic production of organic matter; and (7) conversion of organic matter into fuels.

Solar wind and extreme ultraviolet modulation of the lunar ionosphere/exosphere

NASA Technical Reports Server (NTRS)

Freeman, J. W.

1976-01-01

The ALSEP/SIDE detectors routinely monitor the dayside lunar ionosphere. Variations in the ionosphere are found to correlate with both the 2800 MHz radio index which can be related to solar EUV and with the solar wind proton flux. For the solar wind, the ionospheric variation is proportionately greater than that of the solar wind. This suggests an amplification effect on the lunar atmosphere due perhaps to sputtering of the surface or, less probably, an inordinate enhancement of noble gases in the solar wind. The surface neutral number density is calculated under the assumption of neon gas. During a quiet solar wind this number agrees with or is slightly above that expected for neon accreted from the solar wind. During an enhanced solar wind the neutral number density is much higher.

Solar Energy Directory: A Directory of Domestic and International Firms Involved in Solar Energy.

ERIC Educational Resources Information Center

Centerline Co., Phoenix, AZ.

This directory is intended to provide a link between suppliers of solar energy technology and information and potential users of these products. Included are over 1400 national and international entries. These listings include architects, associations, education sources, wind power technology and information sources, solar research organizations,…

Interaction between Solar Wind and Lunar Magnetic Anomalies observed by Kaguya MAP-PACE

NASA Astrophysics Data System (ADS)

Saito, Yoshifumi; Yokota, Shoichiro; Tanaka, Takaaki; Asamura, Kazushi; Nishino, Masaki; Yamamoto, Tadateru; Uemura, Kota; Tsunakawa, Hideo

2010-05-01

It is known that Moon has neither global intrinsic magnetic field nor thick atmosphere. Different from the Earth's case where the intrinsic global magnetic field prevents the solar wind from penetrating into the magnetosphere, solar wind directly impacts the lunar surface. Since the discovery of the lunar crustal magnetic field in 1960s, several papers have been published concerning the interaction between the solar wind and the lunar magnetic anomalies. MAG/ER on Lunar Prospector found heating of the solar wind electrons presumably due to the interaction between the solar wind and the lunar magnetic anomalies and the existence of the mini-magnetosphere was suggested. However, the detailed mechanism of the interaction has been unclear mainly due to the lack of the in-situ observed data of low energy ions. MAgnetic field and Plasma experiment - Plasma energy Angle and Composition Experiment (MAP-PACE) on Kaguya (SELENE) completed its ˜1.5-year observation of the low energy charged particles around the Moon on 10 June, 2009. Kaguya was launched on 14 September 2007 by H2A launch vehicle from Tanegashima Space Center in Japan. Kaguya was inserted into a circular lunar polar orbit of 100km altitude and continued observation for nearly 1.5 years till it impacted the Moon on 10 June 2009. During the last 5 months, the orbit was lowered to ˜50km-altitude between January 2009 and April 2009, and some orbits had further lower perilune altitude of ˜10km after April 2009. MAP-PACE consisted of 4 sensors: ESA (Electron Spectrum Analyzer)-S1, ESA-S2, IMA (Ion Mass Analyzer), and IEA (Ion Energy Analyzer). All the sensors performed quite well as expected from the laboratory experiment carried out before launch. Since each sensor had hemispherical field of view, two electron sensors and two ion sensors that were installed on the spacecraft panels opposite to each other could cover full 3-dimensional phase space of low energy electrons and ions. One of the ion sensors IMA was an energy mass spectrometer. IMA measured mass identified ion energy spectra that had never been obtained at 100km altitude polar orbit around the Moon. When Kaguya flew over South Pole Aitken region, where strong magnetic anomalies exist, solar wind ions reflected by magnetic anomalies were observed. These ions had much higher flux than the solar wind protons scattered at the lunar surface. The magnetically reflected ions had nearly the same energy as the incident solar wind ions while the solar wind protons scattered at the lunar surface had slightly lower energy than the incident solar wind ions. At 100km altitude, when the reflected ions were observed, the simultaneously measured electrons were often heated and the incident solar wind ions were sometimes slightly decelerated. At ~50km altitude, when the reflected ions were observed, proton scattering at the lunar surface clearly disappeared. It suggests that there exists an area on the lunar surface where solar wind does not impact. At ~10km altitude, the interaction between the solar wind ions and the lunar magnetic anomalies was remarkable with clear deceleration of the incident solar wind ions and heating of the reflected ions as well as significant heating of the electrons. Calculating velocity moments including density, velocity, temperature of the ions and electrons, we have found that there exists 100km scale regions over strong magnetic anomalies where plasma parameters are quite different from the outside. Solar wind ions observed at 10km altitude show several different behaviors such as deceleration without heating and heating in a limited region inside the magnetic anomalies that may be caused by the magnetic field structure. The deceleration of the solar wind has the same ΔE/q (ΔE : deceleration energy, q: charge) for different species, which constraints the possible mechanisms of the interaction between solar wind and magnetic anomalies.

Elemental and charge state composition of the fast solar wind observed with SMS instruments on WIND

NASA Technical Reports Server (NTRS)

Gloeckler, G.; Galvin, A. B.; Ipavich, F. M.; Hamilton, D. C.; Bochsler, P.; Geiss, J.; Fisk, L. A.; Wilken, B.

1995-01-01

The elemental composition and charge state distributions of heavy ions of the solar wind provide essential information about: (1) atom-ion separation processes in the solar atmosphere leading to the 'FIP effect' (the overabundance of low First Ionization potential (FIP) elements in the solar wind compared to the photosphere); and (2) coronal temperature profiles, as well as mechanisms which heat the corona and accelerate the solar wind. This information is required for solar wind acceleration models. The SWICS instrument on Ulysses measures for all solar wind flow conditions the relative abundance of about 8 elements and 20 charge states of the solar wind. Furthermore, the Ulysses high-latitude orbit provides an unprecedented look at the solar wind from the polar coronal holes near solar minimum conditions. The MASS instrument on the WIND spacecraft is a high-mass resolution solar wind ion mass spectrometer that will provide routinely not only the abundances and charge state of all elements easily measured with SWICS, but also of N, Mg, S. The MASS sensor was fully operational at the end of 1994 and has sampled the in-ecliptic solar wind composition in both the slow and the corotating fast streams. This unique combination of SWICS on Ulysses and MASS on WIND allows us to view for the first time the solar wind from two regions of the large coronal hole. Observations with SWICS in the coronal hole wind: (1) indicate that the FIP effect is small; and (2) allow us determine the altitude of the maximum in the electron temperature profile, and indicate a maximum temperature of approximately 1.5 MK. New results from the SMS instruments on Wind will be compared with results from SWICS on Ulysses.

A study of the solar wind deceleration in the Earth's foreshock region

NASA Technical Reports Server (NTRS)

Zhang, T.-L.; Schwingenschuh, K.; Russell, C. T.

1995-01-01

Previous observations have shown that the solar wind is decelerated and deflected in the earth's upstream region populated by long-period waves. This deceleration is corelated with the 'diffuse' but not with the 'reflected' ion population. The speed of the solar wind may decrease tens of km/s in the foreshock region. The solar wind dynamic pressure exerted on the magnetopause may vary due to the fluctuation of the solar wind speed and density in the foreshock region. In this study, we examine this solar wind deceleration and determine how the solar wind deceleration varies in the foreshock region.

Solar Corona/Wind Composition and Origins of the Solar Wind

NASA Astrophysics Data System (ADS)

Lepri, S. T.; Gilbert, J. A.; Landi, E.; Shearer, P.; von Steiger, R.; Zurbuchen, T.

2014-12-01

Measurements from ACE and Ulysses have revealed a multifaceted solar wind, with distinctly different kinetic and compositional properties dependent on the source region of the wind. One of the major outstanding issues in heliophysics concerns the origin and also predictability of quasi-stationary slow solar wind. While the fast solar wind is now proven to originate within large polar coronal holes, the source of the slow solar wind remains particularly elusive and has been the subject of long debate, leading to models that are stationary and also reconnection based - such as interchange or so-called S-web based models. Our talk will focus on observational constraints of solar wind sources and their evolution during the solar cycle. In particular, we will point out long-term variations of wind composition and dynamic properties, particularly focused on the abundance of elements with low First Ionization Potential (FIP), which have been routinely measured on both ACE and Ulysses spacecraft. We will use these in situ observations, and remote sensing data where available, to provide constraints for solar wind origin during the solar cycle, and on their correspondence to predictions for models of the solar wind.

25 CFR 162.538 - What is the purpose of a WSR lease?

Code of Federal Regulations, 2014 CFR

2014-04-01

... maintenance of wind and/or solar energy resource development projects. Activities include installing... Wind and Solar Resource Leases Wsr Leases § 162.538 What is the purpose of a WSR lease? A WSR lease... electricity and other related activities. Leases for biomass or waste-to-energy purposes are governed by...

25 CFR 162.538 - What is the purpose of a WSR lease?

Code of Federal Regulations, 2013 CFR

2013-04-01

... maintenance of wind and/or solar energy resource development projects. Activities include installing... Wind and Solar Resource Leases Wsr Leases § 162.538 What is the purpose of a WSR lease? A WSR lease... electricity and other related activities. Leases for biomass or waste-to-energy purposes are governed by...

KINEMATIC TREATMENT OF CORONAL MASS EJECTION EVOLUTION IN THE SOLAR WIND

NASA Technical Reports Server (NTRS)

Riley, Pete; Crooker, N. U.

2004-01-01

We present a kinematic study of the evolution of coronal mass ejections (CMEs) in the solar wind. Specifically, we consider the effects of (1) spherical expansion and (2) uniform expansion due to pressure gradients between the interplanetary CME (ICME) and the ambient solar wind. We compare these results with an MHD model that allows us to isolate these effects h m the combined kinematic and dynamical effects, which are included in MHD models. They also provide compelling evidence that the fundamental cross section of so-called "force-free" flux ropes (or magnetic clouds) is neither circular or elliptical, but rather a convex-outward, "pancake" shape. We apply a force-free fit to the magnetic vectors from the MHD simulation to assess how the distortion of the flux rope affects the fit. In spite of these limitations, force-free fits, which are straightforward to apply, do provide an important description of a number of parameters, including the radial dimension, orientation, and chirality of the ICME. Subject headings: MHD - solar wind - Sun: activity - Sun: corona - Sun: coronal mass ejections (CMEs) - On-line material color figures Sun: magnetic fields

Global map of solar power production efficiency, considering micro climate factors

NASA Astrophysics Data System (ADS)

Hassanpour Adeh, E.; Higgins, C. W.

2017-12-01

Natural resources degradation and greenhouse gas emissions are creating a global crisis. Renewable energy is the most reliable option to mitigate this environmental dilemma. Abundancy of solar energy makes it highly attractive source of electricity. The existing global spatial maps of available solar energy are created with various models which consider the irradiation, latitude, cloud cover, elevation, shading and aerosols, and neglect the influence of local meteorological conditions. In this research, the influences of microclimatological variables on solar energy productivity were investigated with an in-field study at the Rabbit Hills solar arrays near Oregon State University. The local studies were extended to a global level, where global maps of solar power were produced, taking the micro climate variables into account. These variables included: temperature, relative humidity, wind speed, wind direction, solar radiation. The energy balance approach was used to synthesize the data and compute the efficiencies. The results confirmed that the solar power efficiency can be directly affected by the air temperature and wind speed.

Smart Grid Maturity Model: Model Definition. A Framework for Smart Grid Transformation

DTIC Science & Technology

2010-09-01

adoption of more efficient and reliable generation sources and would allow consumer-generated electricity (e.g., solar power and wind) to be connected to...program that pays customers (or credits their accounts) for customer-provided electricity such as from solar panels to the grid or electric vehicles...deployed. CUST-5.3 Plug-and-play customer-based generation (e.g., wind and solar ) is supported. This includes the necessary infrastructure, such

Solar Energy.

ERIC Educational Resources Information Center

Eaton, William W.

Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

Validation for Global Solar Wind Prediction Using Ulysses Comparison: Multiple Coronal and Heliospheric Models Installed at the Community Coordinated Modeling Center

NASA Technical Reports Server (NTRS)

Jian, L. K.; MacNeice, P. J.; Mays, M. L.; Taktakishvili, A.; Odstrcil, D.; Jackson, B.; Yu, H.-S.; Riley, P.; Sokolov, I. V.

2016-01-01

The prediction of the background global solar wind is a necessary part of space weather forecasting. Several coronal and heliospheric models have been installed and/or recently upgraded at the Community Coordinated Modeling Center (CCMC), including the Wang-Sheely-Arge (WSA)-Enlil model, MHD-Around-a-Sphere (MAS)-Enlil model, Space Weather Modeling Framework (SWMF), and Heliospheric tomography using interplanetary scintillation data. Ulysses recorded the last fast latitudinal scan from southern to northern poles in 2007. By comparing the modeling results with Ulysses observations over seven Carrington rotations, we have extended our third-party validation from the previous near-Earth solar wind to middle to high latitudes, in the same late declining phase of solar cycle 23. Besides visual comparison, wehave quantitatively assessed the models capabilities in reproducing the time series, statistics, and latitudinal variations of solar wind parameters for a specific range of model parameter settings, inputs, and grid configurations available at CCMC. The WSA-Enlil model results vary with three different magnetogram inputs.The MAS-Enlil model captures the solar wind parameters well, despite its underestimation of the speed at middle to high latitudes. The new version of SWMF misses many solar wind variations probably because it uses lower grid resolution than other models. The interplanetary scintillation-tomography cannot capture the latitudinal variations of solar wind well yet. Because the model performance varies with parameter settings which are optimized for different epochs or flow states, the performance metric study provided here can serve as a template that researchers can use to validate the models for the time periods and conditions of interest to them.

Long-term Trends in the Solar Wind Proton Measurements

NASA Astrophysics Data System (ADS)

Elliott, Heather A.; McComas, David J.; DeForest, Craig E.

2016-11-01

We examine the long-term time evolution (1965-2015) of the relationships between solar wind proton temperature (T p) and speed (V p) and between the proton density (n p) and speed using OMNI solar wind observations taken near Earth. We find a long-term decrease in the proton temperature-speed (T p-V p) slope that lasted from 1972 to 2010, but has been trending upward since 2010. Since the solar wind proton density-speed (n p-V p) relationship is not linear like the T p-V p relationship, we perform power-law fits for n p-V p. The exponent (steepness in the n p-V p relationship) is correlated with the solar cycle. This exponent has a stronger correlation with current sheet tilt angle than with sunspot number because the sunspot number maxima vary considerably from cycle to cycle and the tilt angle maxima do not. To understand this finding, we examined the average n p for different speed ranges, and found that for the slow wind n p is highly correlated with the sunspot number, with a lag of approximately four years. The fast wind n p variation was less, but in phase with the cycle. This phase difference may contribute to the n p-V p exponent correlation with the solar cycle. These long-term trends are important since empirical formulas based on fits to T p and V p data are commonly used to identify interplanetary coronal mass ejections, but these formulas do not include any time dependence. Changes in the solar wind density over a solar cycle will create corresponding changes in the near-Earth space environment and the overall extent of the heliosphere.

Validation for global solar wind prediction using Ulysses comparison: Multiple coronal and heliospheric models installed at the Community Coordinated Modeling Center

NASA Astrophysics Data System (ADS)

Jian, L. K.; MacNeice, P. J.; Mays, M. L.; Taktakishvili, A.; Odstrcil, D.; Jackson, B.; Yu, H.-S.; Riley, P.; Sokolov, I. V.

2016-08-01

The prediction of the background global solar wind is a necessary part of space weather forecasting. Several coronal and heliospheric models have been installed and/or recently upgraded at the Community Coordinated Modeling Center (CCMC), including the Wang-Sheely-Arge (WSA)-Enlil model, MHD-Around-a-Sphere (MAS)-Enlil model, Space Weather Modeling Framework (SWMF), and heliospheric tomography using interplanetary scintillation data. Ulysses recorded the last fast latitudinal scan from southern to northern poles in 2007. By comparing the modeling results with Ulysses observations over seven Carrington rotations, we have extended our third-party validation from the previous near-Earth solar wind to middle to high latitudes, in the same late declining phase of solar cycle 23. Besides visual comparison, we have quantitatively assessed the models' capabilities in reproducing the time series, statistics, and latitudinal variations of solar wind parameters for a specific range of model parameter settings, inputs, and grid configurations available at CCMC. The WSA-Enlil model results vary with three different magnetogram inputs. The MAS-Enlil model captures the solar wind parameters well, despite its underestimation of the speed at middle to high latitudes. The new version of SWMF misses many solar wind variations probably because it uses lower grid resolution than other models. The interplanetary scintillation-tomography cannot capture the latitudinal variations of solar wind well yet. Because the model performance varies with parameter settings which are optimized for different epochs or flow states, the performance metric study provided here can serve as a template that researchers can use to validate the models for the time periods and conditions of interest to them.

MHD Modeling of the Solar Wind with Turbulence Transport and Heating

NASA Technical Reports Server (NTRS)

Goldstein, M. L.; Usmanov, A. V.; Matthaeus, W. H.; Breech, B.

2009-01-01

We have developed a magnetohydrodynamic model that describes the global axisymmetric steady-state structure of the solar wind near solar minimum with account for transport of small-scale turbulence associated heating. The Reynolds-averaged mass, momentum, induction, and energy equations for the large-scale solar wind flow are solved simultaneously with the turbulence transport equations in the region from 0.3 to 100 AU. The large-scale equations include subgrid-scale terms due to turbulence and the turbulence (small-scale) equations describe the effects of transport and (phenomenologically) dissipation of the MHD turbulence based on a few statistical parameters (turbulence energy, normalized cross-helicity, and correlation scale). The coupled set of equations is integrated numerically for a source dipole field on the Sun by a time-relaxation method in the corotating frame of reference. We present results on the plasma, magnetic field, and turbulence distributions throughout the heliosphere and on the role of the turbulence in the large-scale structure and temperature distribution in the solar wind.

Solar wind structure out of the ecliptic plane over solar cycles

NASA Astrophysics Data System (ADS)

Sokol, J. M.; Bzowski, M.; Tokumaru, M.

2017-12-01

Sun constantly emits a stream of plasma known as solar wind. Ground-based observations of the solar wind speed through the interplanetary scintillations (IPS) of radio flux from distant point sources and in-situ measurements by Ulysses mission revealed that the solar wind flow has different characteristics depending on the latitude. This latitudinal structure evolves with the cycle of solar activity. The knowledge on the evolution of solar wind structure is important for understanding the interaction between the interstellar medium surrounding the Sun and the solar wind, which is responsible for creation of the heliosphere. The solar wind structure must be taken into account in interpretation of most of the observations of heliospheric energetic neutral atoms, interstellar neutral atoms, pickup ions, and heliospheric backscatter glow. The information on the solar wind structure is not any longer available from direct measurements after the termination of Ulysses mission and the only source of the solar wind out of the ecliptic plane is the IPS observations. However, the solar wind structure obtained from this method contains inevitable gaps in the time- and heliolatitude coverage. Sokół et al 2015 used the solar wind speed data out of the ecliptic plane retrieved from the IPS observations performed by Institute for Space-Earth Environmental Research (Nagoya University, Japan) and developed a methodology to construct a model of evolution of solar wind speed and density from 1985 to 2013 that fills the data gaps. In this paper we will present a refined model of the solar wind speed and density structure as a function of heliographic latitude updated by the most recent data from IPS observations. And we will discuss methods of extrapolation of the solar wind structure out of the ecliptic plane for the past solar cycles, when the data were not available, as well as forecasting for few years upward.

Windsock memory COnditioned RAM (CO-RAM) pressure effect: Forced reconnection in the Earth's magnetotail

NASA Astrophysics Data System (ADS)

Vörös, Z.; Facskó, G.; Khodachenko, M.; Honkonen, I.; Janhunen, P.; Palmroth, M.

2014-08-01

Magnetic reconnection (MR) is a key physical concept explaining the addition of magnetic flux to the magnetotail and closed flux lines back-motion to the dayside magnetosphere. This scenario elaborated by Dungey (1963) can explain many aspects of solar wind-magnetosphere interaction processes, including substorms. However, neither the Dungey model nor its numerous modifications were able to explain fully the onset conditions for MR in the tail. In this paper, we introduce new onset conditions for forced MR in the tail. We call our scenario the "windsock memory conditioned ram pressure effect." Our nonflux transfer-associated forcing is introduced by a combination of the large-scale windsock motions exhibiting memory effects and solar wind dynamic pressure actions on the nightside magnetopause during northward oriented interplanetary magnetic field (IMF). Using global MHD Grand Unified Magnetosphere Ionosphere Coupling Simulation version 4 simulation results, upstream data from Wind, magnetosheath data from Cluster 1 and distant tail data from the two-probe Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun mission, we show that the simultaneous occurrence of vertical windsock motions of the magnetotail and enhanced solar wind dynamic pressure introduces strong nightside disturbances, including enhanced electric fields and persistent vertical cross-tail shear flows. These perturbations, associated with a stream interaction region in the solar wind, drive MR in the tail during episodes of northward oriented interplanetary magnetic field (IMF). We detect MR indirectly, observing plasmoids in the tail and ground-based signatures of earthward moving fast flows. We also consider the application to solar system planets and close-in exoplanets, where the proposed scenario can elucidate some new aspects of solar/stellar wind-magnetosphere interactions.

Solar-Planetary Relationships: Magnetospheric Physics

NASA Technical Reports Server (NTRS)

Barnes, Aaron

1979-01-01

The quadrennium 1975-1978 was a period of great advance for solar-wind studies, a period that combined exploration of new regions with increased maturity in established fields of study. The Helios, Pioneer, and Voyager spacecraft have been exploring the inner and outer regions of the solar wind. There has been a rebirth of the study of possible relations between solar variability and Earth's climate and weather, stimulated largely by Eddy's investigation of the Maunder Minimum; the solar wind may well prove to be a significant link in solar-terrestrial relations. Unique coronal data from the SKYLAB 1973-1974 mission, in combination with satellite and ground-based observations, provided the basis for identification of coronal holes as the main source of highspeed solar wind. The interplanetary medium has continued to serve as a laboratory for the study of plasma processes that cannot yet be studied in terrestrial laboratories, providing insights of potential importance both for controlled fusion research and for astrophysics. It is ironic that such a productive period, the legacy of many past space missions, was also a time of severely limited opportunity for new space investigations; the outlook for the future is equally austere. Especially regrettable is the dearth of career opportunities for young scientists in this field; comparison of the bibliography of this report with that of its predecessor 4 years ago shows few new names. Despite such problems, research has continued with enthusiasm and much has been learned. The present report will survey selected topics related to the origin, expansion, and acceleration of the solar wind and the plasma physics of the interplanetary medium. Companion reports deal with a number of closely related topics, including the heliocentric distance and latitude variation of the solar wind and its fluctuations topology of the interplanetary magnetic field morphology of solar-wind streams and shocks, sunweather studies, and interplanetary manifestations of type-3 bursts. Of the subjects that fall within the scope of this report, the study of the relationship between coronal holes and solar-wind streams, and the associated revision of our ideas about solar wind acceleration and heating, have had the most impact; hence I review these topics in considerable detail. In addition, I discuss the topics of hydromagnetic waves and turbulence, and interplanetary electrons, as items of particular importance during the past quadrennium.

The interaction of the solar wind with the interstellar medium

NASA Technical Reports Server (NTRS)

Axford, W. I.

1972-01-01

The expected characteristics of the solar wind, extrapolated from the vicinity of the earth are described. Several models are examined for the interaction of the solar wind with the interstellar plasma and magnetic field. Various aspects of the penetration of neutral interstellar gas into the solar wind are considered. The dynamic effects of the neutral gas on the solar wind are described. Problems associated with the interaction of cosmic rays with the solar wind are discussed.

Neutral Solar Wind Generated by Lunar Exospheric Dust at the Terminator

NASA Technical Reports Server (NTRS)

Collier, Michael R.; Stubbs, Timothy J.

2007-01-01

We calculate the flux of neutral solar wind observed on the lunar surface at the terminator due to solar wind protons penetrating exospheric dust with: (1) grains larger that 0.1 microns and (2) grains larger than 0.01 microns. For grains larger than 0.1 microns, the ratio of the neutral solar wind to solar wind flux is estimated to be approx.10(exp -4)-10(exp -3) at solar wind speeds in excess of 800 km/s, but much lower (less than 10(exp -5) at average to low solar wind speeds. However, when the smaller grain sizes are considered, the ratio of the neutral solar wind flux to solar wind flux is estimated to be greater than or equal to 10(exp -5) at all speeds and at speeds in excess of 700 km/s reaches 10(exp -3)-10(exp -2). These neutral solar wind fluxes are easily measurable with current low energy neutral atom instrumentation. Observations of neutral solar wind from the surface of the Moon could provide a very sensitive determination of the distribution of very small dust grains in the lunar exosphere and would provide data complementary to optical measurements at ultraviolet and visible wavelengths. Furthermore, neutral solar wind, unlike its ionized counterpart, is .not held-off by magnetic anomalies, and may contribute to greater space weathering than expected in certain lunar locations.

Solar-wind velocity measurements from near-Sun comets C/2011 W3 (Lovejoy), C/2011 L4 (Pan-STARRS), and C/2012 S1 (ISON)

NASA Astrophysics Data System (ADS)

Ramanjooloo, Y.; Jones, G. H.; Coates, A.; Owens, M. J.; Battams, K.

2014-07-01

Since the mid-20th century, comets' plasma (type I) tails have been studied as natural probes of the solar wind [1]. Comets have induced magnetotails, formed through the draping of the heliospheric magnetic field by the velocity shear in the mass-loaded solar wind. These can be easily observed remotely as the comets' plasma tails, which generally point away from the Sun. Local solar-wind conditions directly influence the morphology and dynamics of a comet's plasma tail. During ideal observing geometries, the orientation and structure of the plasma tail can reveal large-scale and small-scale variations in the local solar-wind structure. These variations can be manifested as tail condensations, kinks, and disconnection events. Over 50 % of observed catalogued comets are sungrazing comets [2], fragments of three different parent comets. Since 2011, two bright new comets, C/2011 W3 [3] (from hereon comet Lovejoy) and C/2012 S1 [4] (hereon comet ISON) have experienced extreme solar-wind conditions and insolation of their nucleus during their perihelion passages, approaching to within 8.3×10^5 km (1.19 solar radii) and 1.9×10^6 km (2.79 solar radii) of the solar centre. They each displayed a prominent plasma tail, proving to be exceptions amongst the observed group of sungrazing comets. These bright sungrazers provide unprecedented access to study the solar wind in the heretofore unprobed innermost region of the solar corona. The closest spacecraft in-situ sampling of the solar wind by the Helios probes reached 0.29 au. For this study, we define a sungrazing comet as one with its perihelion within the solar Roche limit (3.70 solar radii). We also extend this study to include C/2011 L4 [5] (comet Pan-STARRS), a comet with a much further perihelion distance of 0.302 au. The technique employed in this study was first established by analysing geocentric amateur observations of comets C/2001 Q4 (NEAT) and C/2004 Q2 (Machholz) [7]. These amateur images, obtained with modern equipment and sensors, rival and sometimes arguably exceed the quality of professional images obtained only 2--3 decades ago. Multiple solar-wind velocity estimates were derived from each image and the results compared to observed and modelled near-Earth solar-wind data. Our unique analysis technique [Ramanjooloo et al., in preparation] allows us to determine the latitudinal variations of the solar wind, heliospheric current-sheet sector boundaries and the boundaries of transient features as a comet with an observable plasma tail probes the inner heliosphere. We present solar-wind velocity measurements derived from multiple observing locations of comets Lovejoy from the 14th -- 19th December 2011, comet Pan-STARRS during 11th -- 16th March 2013 and comet ISON from 12th -- 29th November 2013. Observations were gathered from multiple resources, from the SECCHI heliospheric imagers aboard STEREO A and B [8], the LASCO coronagraphs aboard SOHO [9], as well as ground-based amateur and professional observations coordinated by the CIOC. Overlapping observation sessions from the three spacecraft and ground-based efforts provided the perfect opportunity to use these comets as a diagnostic tool to understand solar-wind variability close to the Sun. We plan to compare our observations to results of suitable simulations [10] of plasma conditions in the corona and inner heliosphere during each of the comets' perihelion passage. The correlation of the solar-wind velocity distribution from different observing locations can provide clues towards the morphology and orientation of the plasma tail. We also attempt to determine the difficult-to-determine non-radial components of the measured solar-wind velocities.

Solar wind dynamic pressure and electric field as the main factors controlling Saturn's aurorae.

PubMed

Crary, F J; Clarke, J T; Dougherty, M K; Hanlon, P G; Hansen, K C; Steinberg, J T; Barraclough, B L; Coates, A J; Gérard, J-C; Grodent, D; Kurth, W S; Mitchell, D G; Rymer, A M; Young, D T

2005-02-17

The interaction of the solar wind with Earth's magnetosphere gives rise to the bright polar aurorae and to geomagnetic storms, but the relation between the solar wind and the dynamics of the outer planets' magnetospheres is poorly understood. Jupiter's magnetospheric dynamics and aurorae are dominated by processes internal to the jovian system, whereas Saturn's magnetosphere has generally been considered to have both internal and solar-wind-driven processes. This hypothesis, however, is tentative because of limited simultaneous solar wind and magnetospheric measurements. Here we report solar wind measurements, immediately upstream of Saturn, over a one-month period. When combined with simultaneous ultraviolet imaging we find that, unlike Jupiter, Saturn's aurorae respond strongly to solar wind conditions. But in contrast to Earth, the main controlling factor appears to be solar wind dynamic pressure and electric field, with the orientation of the interplanetary magnetic field playing a much more limited role. Saturn's magnetosphere is, therefore, strongly driven by the solar wind, but the solar wind conditions that drive it differ from those that drive the Earth's magnetosphere.

Imprint of the Sun’s Evolving Polar Winds on IBEX Energetic Neutral Atom All-sky Observations of the Heliosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zirnstein, E. J.; McComas, D. J.; Dayeh, M. A.

2017-09-01

With 7 years of Interstellar Boundary Explorer ( IBEX ) measurements of energetic neutral atoms (ENAs), IBEX has shown a clear correlation between dynamic changes in the solar wind and the heliosphere’s response in the formation of ENAs. In this paper, we investigate temporal variations in the latitudinal-dependent ENA spectrum from IBEX and their relationship to the solar wind speed observed at 1 au. We find that the variation in latitude of the transition in ENA spectral indices between low (≲1.8) and high (≳1.8) values, as well as the distribution of ENA spectral indices at high and low latitudes, correlatesmore » well with the evolution of the fast and slow solar wind latitudinal structure observed near 1 au. This correlation includes a delay due to the time it takes the solar wind to propagate to the termination shock and into the inner heliosheath, and for ENAs to be generated via charge-exchange and travel back toward 1 au. Moreover, we observe a temporal asymmetry in the steepening of the ENA spectrum in the northern and southern hemispheres, consistent with asymmetries observed in the solar wind and polar coronal holes. While this asymmetry is observed near the upwind direction of the heliosphere, it is not yet observed in the tail direction, suggesting a longer line-of-sight integration distance or different processing of the solar wind plasma downstream of the termination shock.« less

The ancient sun: Fossil record in the earth, moon and meteorites; Proceedings of the Conference, Boulder, CO, October 16-19, 1979

NASA Technical Reports Server (NTRS)

Pepin, R. O. (Editor); Eddy, J. A.; Merrill, R. B.

1980-01-01

Papers are presented concerning theories of solar variability and their consequences for luminosity, particle emission and magnetic field changes within the past 4.5 billion years, and on the records of such solar behavior in lunar, meteoritic and terrestrial materials. Specific topics include the neutrino luminosity of the sun, the relation of sunspots to the terrestrial climate of the past 100 years, solar modulation of galactic cosmic rays, the historical record of solar activity, C-14 variations in terrestrial and marine reservoirs, and solar particle fluxes as indicated by track, thermoluminescence and solar wind measurements in lunar rocks. Attention is also given to the spin-down of the solar interior through circulation currents and fluid instabilities, grain surface exposure models in planetary regoliths, rare gases in the solar wind, nitrogen isotopic variations in the lunar regolith, the influence of solar UV radiation on climate, and the pre-main sequence evolution of the sun and evidence of the primordial solar wind in the electromagnetic induction heating of the asteroids and moon.

Turbulence-driven coronal heating and improvements to empirical forecasting of the solar wind

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woolsey, Lauren N.; Cranmer, Steven R.

Forecasting models of the solar wind often rely on simple parameterizations of the magnetic field that ignore the effects of the full magnetic field geometry. In this paper, we present the results of two solar wind prediction models that consider the full magnetic field profile and include the effects of Alfvén waves on coronal heating and wind acceleration. The one-dimensional magnetohydrodynamic code ZEPHYR self-consistently finds solar wind solutions without the need for empirical heating functions. Another one-dimensional code, introduced in this paper (The Efficient Modified-Parker-Equation-Solving Tool, TEMPEST), can act as a smaller, stand-alone code for use in forecasting pipelines. TEMPESTmore » is written in Python and will become a publicly available library of functions that is easy to adapt and expand. We discuss important relations between the magnetic field profile and properties of the solar wind that can be used to independently validate prediction models. ZEPHYR provides the foundation and calibration for TEMPEST, and ultimately we will use these models to predict observations and explain space weather created by the bulk solar wind. We are able to reproduce with both models the general anticorrelation seen in comparisons of observed wind speed at 1 AU and the flux tube expansion factor. There is significantly less spread than comparing the results of the two models than between ZEPHYR and a traditional flux tube expansion relation. We suggest that the new code, TEMPEST, will become a valuable tool in the forecasting of space weather.« less

Three Dimensional Explicit Model for Cometary Tail Ions Interactions with Solar Wind

NASA Astrophysics Data System (ADS)

Al Bermani, M. J. F.; Alhamed, S. A.; Khalaf, S. Z.; Ali, H. Sh.; Selman, A. A.

2009-06-01

The different interactions between cometary tail and solar wind ions are studied in the present paper based on three-dimensional Lax explicit method. The model used in this research is based on the continuity equations describing the cometary tail-solar wind interactions. Three dimensional system was considered in this paper. Simulation of the physical system was achieved using computer code written using Matlab 7.0. The parameters studied here assumed Halley comet type and include the particle density rho, the particles velocity v, the magnetic field strength B, dynamic pressure p and internal energy E. The results of the present research showed that the interaction near the cometary nucleus is mainly affected by the new ions added to the plasma of the solar wind, which increases the average molecular weight and result in many unique characteristics of the cometary tail. These characteristics were explained in the presence of the IMF.

A unified high-resolution wind and solar dataset from a rapidly updating numerical weather prediction model

DOE PAGES

James, Eric P.; Benjamin, Stanley G.; Marquis, Melinda

2016-10-28

A new gridded dataset for wind and solar resource estimation over the contiguous United States has been derived from hourly updated 1-h forecasts from the National Oceanic and Atmospheric Administration High-Resolution Rapid Refresh (HRRR) 3-km model composited over a three-year period (approximately 22 000 forecast model runs). The unique dataset features hourly data assimilation, and provides physically consistent wind and solar estimates for the renewable energy industry. The wind resource dataset shows strong similarity to that previously provided by a Department of Energy-funded study, and it includes estimates in southern Canada and northern Mexico. The solar resource dataset represents anmore » initial step towards application-specific fields such as global horizontal and direct normal irradiance. This combined dataset will continue to be augmented with new forecast data from the advanced HRRR atmospheric/land-surface model.« less

Wide Field-of-View Soft X-Ray Imaging for Solar Wind-Magnetosphere Interactions

NASA Technical Reports Server (NTRS)

Walsh, B. M.; Collier, M. R.; Kuntz, K. D.; Porter, F. S.; Sibeck, D. G.; Snowden, S. L.; Carter, J. A.; Collado-Vega, Y.; Connor, H. K.; Cravens, T. E.;

Interaction of solar wind with the magnetopause-boundary layer and generation of magnetic impulse events

NASA Technical Reports Server (NTRS)

Lee, L. C.; Wei, C. Q.

1993-01-01

The transport of mass, momentum, energy and waves from the solar wind to the Earth's magnetosphere takes place in the magnetopause-boundary layer region. Various plasma processes that may occur in this region have been proposed and studied. In this paper, we present a brief review of the plasma processes in the dayside magnetopause-boundary layer. These processes include (1) flux transfer events at the dayside magnetopause, (2) formation of plasma vortices in the low-latitude boundary layer by the Kelvin-Helmholtz instability and coupling to the polar ionosphere, (3) the response of the magnetopause to the solar wind dynamic pressure pulses, and (4) the impulsive penetration of solar wind plasma filaments through the dayside magnetopause into the magnetospheric boundary layer. Through the coupling of the magnetopause-boundary layer to the polar ionosphere, those above processes may lead to occurrence of magnetic impulse events observed in the high-latitude stations.

Ensemble Space-Time Correlation of Plasma Turbulence in the Solar Wind.

PubMed

Matthaeus, W H; Weygand, J M; Dasso, S

2016-06-17

Single point measurement turbulence cannot distinguish variations in space and time. We employ an ensemble of one- and two-point measurements in the solar wind to estimate the space-time correlation function in the comoving plasma frame. The method is illustrated using near Earth spacecraft observations, employing ACE, Geotail, IMP-8, and Wind data sets. New results include an evaluation of both correlation time and correlation length from a single method, and a new assessment of the accuracy of the familiar frozen-in flow approximation. This novel view of the space-time structure of turbulence may prove essential in exploratory space missions such as Solar Probe Plus and Solar Orbiter for which the frozen-in flow hypothesis may not be a useful approximation.

Relation between the electromagnetic processes in the near-Earth space and dynamics of the biological resources in Russian Arctic

NASA Astrophysics Data System (ADS)

Makarova, L. N.; Shirochkov, A. V.; Tumanov, I. L.

The start of the satellite era in the Space explorations led to new and more profound knowledge of the solar physics and the sources of its activity. From these points of view, it is worthy to examine again the relations between biological processes and the solar activity. We explore the relation between dynamics of the solar activity (including the solar wind) and changes in population of some species of Arctic fauna (lemmings, polar foxes, caribous, wolves, elks, etc.). The data include statistical rows of various lengths (30 80 years). The best correlation between two data sets is found when the solar wind dynamic pressure as well as variations of the total solar irradiance (i.e., level of the solar UV radiation) is taken as the space parameters. Probably the electromagnetic fields of space origin are an important factor determining dynamics of population of the Arctic fauna species.

NASA and energy

NASA Technical Reports Server (NTRS)

1974-01-01

NASA technology contributions to create energy sources include direct solar heating and cooling systems, wind generation of electricity, solar thermal energy turbine drives, solar cells, and techniques for locating, producing, and collecting organic materials for conversion into fuel.

A General Identification of Instabilities in Solar Wind Plasma, and a Particular Application to the WIND Data Set.

NASA Astrophysics Data System (ADS)

Klein, Kristopher; Kasper, Justin; Korreck, Kelly; Alterman, Benjamin

2017-04-01

The role of free-energy driven instabilities in governing heating and acceleration processes in the heliosphere has been studied for over half a century, with significant recent advancements enabled by the statistical analysis of decades worth of observations from missions such as WIND. Typical studies focus on marginal stability boundaries in a reduced parameter space, such as the canonical plasma beta versus temperature anisotropy plane, due to a single source of free energy. We present a more general method of determining stability, accounting for all possible sources of free energy in the constituent plasma velocity distributions. Through this novel implementation, we can efficiently determine if the plasma is linearly unstable, and if so, how many normal modes are growing. Such identification will enabling us to better pinpoint the dominant heating or acceleration processes in solar wind plasma. The theory behind this approach is reviewed, followed by a discussion of our methods for a robust numerical implementation, and an initial application to portions of the WIND data set. Further application of this method to velocity distribution measurements from current missions, including WIND, upcoming missions, including Solar Probe Plus and Solar Orbiter, and missions currently in preliminary phases, such as ESA's THOR and NASA's IMAP, will help elucidate how instabilities shape the evolution of the heliosphere.

Ensemble downscaling in coupled solar wind-magnetosphere modeling for space weather forecasting.

PubMed

Owens, M J; Horbury, T S; Wicks, R T; McGregor, S L; Savani, N P; Xiong, M

2014-06-01

Advanced forecasting of space weather requires simulation of the whole Sun-to-Earth system, which necessitates driving magnetospheric models with the outputs from solar wind models. This presents a fundamental difficulty, as the magnetosphere is sensitive to both large-scale solar wind structures, which can be captured by solar wind models, and small-scale solar wind "noise," which is far below typical solar wind model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical "downscaling" of solar wind model results prior to their use as input to a magnetospheric model. As magnetospheric response can be highly nonlinear, this is preferable to downscaling the results of magnetospheric modeling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8 h filter, then add small-scale structure back in through the addition of random noise with the observed spectral characteristics. Here we use a very simple parameterization of noise based upon the observed probability distribution functions of solar wind parameters, but more sophisticated methods will be developed in the future. An ensemble of results from the simple downscaling scheme are tested using a model-independent method and shown to add value to the magnetospheric forecast, both improving the best estimate and quantifying the uncertainty. We suggest a number of features desirable in an operational solar wind downscaling scheme. Solar wind models must be downscaled in order to drive magnetospheric models Ensemble downscaling is more effective than deterministic downscaling The magnetosphere responds nonlinearly to small-scale solar wind fluctuations.

Interaction between solar wind and lunar magnetic anomalies observed by MAP-PACE on Kaguya

NASA Astrophysics Data System (ADS)

Saito, Yoshifumi; Yokota, Shoichiro; Tanaka, Takaaki; Asamura, Kazushi; Nishino, Masaki N.; Yamamoto, Tadateru I.; Tsunakawa, Hideo

It is well known that the Moon has neither global intrinsic magnetic field nor thick atmosphere. Different from the Earth's case where the intrinsic global magnetic field prevents the solar wind from penetrating into the magnetosphere, solar wind directly impacts the lunar surface. MAgnetic field and Plasma experiment -Plasma energy Angle and Composition Experiment (MAP-PACE) on Kaguya (SELENE) completed its 1.5-year observation of the low energy charged particles around the Moon on 10 June 2009. Kaguya was launched on 14 September 2007 by H2A launch vehicle from Tanegashima Space Center in Japan. Kaguya was inserted into a circular lunar polar orbit of 100km altitude and continued observation for nearly 1.5 years till it impacted the Moon on 10 June 2009. During the last 5 months, the orbit was lowered to 50km-altitude between January 2009 and April 2009, and some orbits had further lower perilune altitude of 10km after April 2009. MAP-PACE consisted of 4 sensors: ESA (Electron Spectrum Analyzer)-S1, ESA-S2, IMA (Ion Mass Analyzer), and IEA (Ion Energy Analyzer). Since each sensor had hemispherical field of view, two electron sensors and two ion sensors that were installed on the spacecraft panels opposite to each other could cover full 3-dimensional phase space of low energy electrons and ions. One of the ion sensors IMA was an energy mass spectrometer. IMA measured mass identified ion energy spectra that had never been obtained at 100km altitude polar orbit around the Moon. When Kaguya flew over South Pole Aitken region, where strong magnetic anomalies exist, solar wind ions reflected by magnetic anomalies were observed. These ions had much higher flux than the solar wind protons scattered at the lunar surface. The magnetically reflected ions had nearly the same energy as the incident solar wind ions while the solar wind protons scattered at the lunar surface had slightly lower energy than the incident solar wind ions. At 100km altitude, when the reflected ions were observed, the simultaneously measured electrons were often heated and the incident solar wind ions were sometimes slightly decelerated. At 50km altitude, when the reflected ions were observed, proton scattering at the lunar surface clearly disappeared. It suggests that there exists an area on the lunar surface where solar wind does not impact. At 10km altitude, the interaction between the solar wind ions and the lunar magnetic anomalies was remarkable with clear deceleration of the incident solar wind ions and heating of the reflected ions as well as significant heating of the electrons. Calculating velocity moments including density, velocity, temperature of the ions and electrons, we have found that there exists 100km scale regions over strong magnetic anomalies where plasma parameters are quite different from the outside. Solar wind ions observed at 10km altitude show several different behaviors such as deceleration without heating and heating in a limited region inside the magnetic anomalies that may be caused by the magnetic field structure. The deceleration of the solar wind has the same ∆E/q (∆E : deceleration energy, q: charge) for different species, which constraints the possible mechanisms of the interaction between solar wind and magnetic anomalies.

Solar Wind Prediction at Pluto During the New Horizons Flyby: Results From a Two-Dimensional Multi-fluid MHD Model of the Outer Heliosphere

NASA Astrophysics Data System (ADS)

Zieger, B.; Toth, G.; Opher, M.; Gombosi, T. I.

2015-12-01

We adapted the outer heliosphere (OH) component of the Space Weather Modeling Framework, which is a 3-D global multi-fluid MHD model of the outer heliosphere with one ion fluid and four neutral populations, for time-dependent 2-D multi-fluid MHD simulations of solar wind propagation from a heliocentric distance of 1 AU up to 50 AU. We used this model to predict the solar wind plasma parameters as well as the interplanetary magnetic field components at Pluto and along the New Horizons trajectory during the whole calendar year of 2015 including the closest approach on July 14. The simulation is run in the solar equatorial plane in the heliographic inertial frame (HGI). The inner boundary conditions along a circle of 1 AU radius are set by near-Earth solar wind observations (hourly OMNI data), assuming that the global solar wind distribution does not change much during a Carrington rotation (27.2753 days). Our 2-D multi-fluid MHD code evolves one ion fluid and two neutral fluids, which are the primary interstellar neutral atoms and the interstellar neutral atoms deflected in the outer heliosheath between the slow bow shock and the heliopause. Spherical expansion effects are properly taken into account for the ions and the solar magnetic field. The inflow parameters of the two neutral fluids (density, temperature, and velocity components) are set at the negative X (HGI) boundary at 50 AU distance, which are taken from previous 3-D global multi-fluid MHD simulations of the heliospheric interface in a much larger simulation box (1500x1500x1500 AU). The inflow velocity vectors of the two neutral fluids define the so-called hydrogen deflection plane. The solar wind ions and the interstellar neutrals interact through charge exchange source terms included in the multi-fluid MHD equations, so the two neutral populations are evolved self-consistently. We validate our model with the available plasma data from New Horizons as well as with Voyager 2 plasma and magnetic field observations within the heliocentric distance of 50 AU. Our new time-dependent 2-D multi-fluid MHD model is generally applicable for solar wind predictions at any outer planet (Jupiter, Saturn, Uranus, Neptune) or spacecraft in the outer heliosphere where charge exchange between solar wind ions and interstellar neutrals play an important role.

76 FR 76153 - Notice of Effectiveness of Exempt Wholesale Generator Status; Caney River Wind Project, LLC...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-06

...] Notice of Effectiveness of Exempt Wholesale Generator Status; Caney River Wind Project, LLC, Mesquite Solar 1, LLC, Copper Crossing Solar LLC, Copper Mountain Solar 1, LLC, Pinnacle Wind, LLC, Bellevue Solar, LLC, Yamhill Solar, LLC, Osage Wind, LLC, Minco Wind II, LLC Take notice that during the month of...

Hybrid simulations of Venus' ionospheric magnetization states

NASA Astrophysics Data System (ADS)

Wiehle, Stefan; Motschmann, Uwe; Fränz, Markus

2013-04-01

The solar wind interaction with the plasma environment of Venus is studied with focus on ionospheric magnetization states using a 3D hybrid simulation code. The plasma environment of Venus was investigated mainly by Pioneer Venus Orbiter (PVO) and the still ongoing Venus Express (VEX) mission. Unlike many other planets, Venus' ionosphere is not shielded by a strong magnetosphere. Hence, data measured by spacecraft like PVO and VEX close to the planet are highly sensitive to solar wind and IMF upstream conditions, which cannot be measured while the spacecraft is inside the magnetosheath region about one hour before and after the closest approach. However, solar wind and IMF are known to change within minutes; ionospheric magnetization states, found by PVO and VEX, are highly dependent on the solar wind upstream pressure and also the magnetic field direction may change rapidly in case of a magnetic sector boundary crossing. When these solar wind induced transition effects occur, the causal change in the solar wind cannot be determined from ionospheric in-situ data. Additionally, with an orbital period of 24 hours, measuring transition timescales of solar wind triggered events is not possible. Our self-consistent simulations aim to provide a global picture of the solar wind interaction with Venus focusing on the effects of upstream fluctuations to the magnetic field in the vicinity of the planet. We use the A.I.K.E.F. (Adaptive Ion Kinetic Electron Fluid) 3D hybrid simulation code to model the entire Venus plasma environment. The simulation grid is refined within the ionosphere in order to resolve strong small-scale gradients of the magnetic field and ion density, a necessity to describe the magnetic field depletion inside the Venus' ionosphere. In contrast to other simulation studies, we apply no boundary conditions for the magnetic field at the planetary surface. Furthermore, we include varying upstream conditions like solar wind velocity and density as well as IMF strength and direction by adjusting these parameters after a first, quasi-stationary state has been reached. This allows for a simulation of dynamic processes like the transition between the magnetized and unmagnetized ionospheric state and fossil fields.

The Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) project

NASA Astrophysics Data System (ADS)

Barnes, D.; Harrison, R. A.; Davies, J. A.; Perry, C. H.; Moestl, C.; Rouillard, A.; Bothmer, V.; Rodriguez, L.; Eastwood, J. P.; Kilpua, E.; Gallagher, P.; Odstrcil, D.

2017-12-01

Understanding solar wind evolution is fundamental to advancing our knowledge of energy and mass transport in the solar system, whilst also being crucial to space weather and its prediction. The advent of truly wide-angle heliospheric imaging has revolutionised the study of solar wind evolution, by enabling direct and continuous observation of both transient and background components of the solar wind as they propagate from the Sun to 1 AU and beyond. The recently completed, EU-funded FP7 Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) project (1st May 2014 - 30th April 2017) combined European expertise in heliospheric imaging, built up over the last decade in particular through leadership of the Heliospheric Imager (HI) instruments aboard NASA's STEREO mission, with expertise in solar and coronal imaging as well as the interpretation of in-situ and radio diagnostic measurements of solar wind phenomena. HELCATS involved: (1) the cataloguing of transient (coronal mass ejections) and background (stream/corotating interaction regions) solar wind structures observed by the STEREO/HI instruments, including estimates of their kinematic properties based on a variety of modelling techniques; (2) the verification of these kinematic properties through comparison with solar source observations and in-situ measurements at multiple points throughout the heliosphere; (3) the assessment of the potential for initialising numerical models based on the derived kinematic properties of transient and background solar wind components; and (4) the assessment of the complementarity of radio observations (Type II radio bursts and interplanetary scintillation) in the detection and analysis of heliospheric structure in combination with heliospheric imaging observations. In this presentation, we provide an overview of the HELCATS project emphasising, in particular, the principal achievements and legacy of this unprecedented project.

The U.S. Air Force in Space 1945 to the Twenty-first Century

DTIC Science & Technology

1998-01-01

reliability. Mariner was the United States’ initial program for interplanetary exploration, It was to be a Venus fly-by to determine solar winds...regarding the solar winds, the ion contours between the Earth and Venus, and the temperature and some of the atmospheric conditions on Venus...the solar system and the universe Including all of the reasons which have been made in one policy statement or another would produce a very long list

Tracing the Solar Wind to its Origin: New Insights from ACE/SWICS Data and SO/HIS Performance Predictions

NASA Astrophysics Data System (ADS)

Stakhiv, Mark

The solar wind is a hot tenuous plasma that continuously streams off of the Sun into the heliosphere. The solar wind is the medium through which coronal mass ejections (CMEs) travel from the Sun to the Earth, where they can disrupt vital space-based technologies and wreak havoc on terrestrial infrastructure. Understanding the solar wind can lead to improved predications of CME arrival time as well as their geoeffectiveness. The solar wind is studied in this thesis through in situ measurements of heavy ions. Several outstanding questions about the solar wind are addressed in this thesis: What is the origin of the solar wind? How is the solar wind heated and accelerated? The charge state distribution and abundance of heavy ions in the solar wind record information about their source location and heating mechanism. This information is largely unchanged from the Sun to the Earth, where it is collected in situ with spacecraft. In this thesis we use data from the Solar Wind Ion Composition Spectrometer (SWICS) that flew on two spacecraft: Ulysses (1990 - 2009) and ACE (1998 - present). We analyze the kinetic and compositional properties of the solar wind with heavy ion data and lay out a unified wind scenario, which states that the solar wind originates from two different sources and regardless of its release mechanism the solar wind is then accelerated by waves. The data from these instruments are the best available to date but still lack the measurement cadence and distribution resolution to fully answer all of the solar wind questions. To address these issues a new heavy ion sensor is being developed to be the next generation of in situ heavy ion measurements. This thesis supports the development of this instrument through the analysis of the sensors measurement properties and the characterization of its geometric factor and efficiencies.

Solar Energy Education. Renewable energy: a background text. [Includes glossary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-01-01

Some of the most common forms of renewable energy are presented in this textbook for students. The topics include solar energy, wind power hydroelectric power, biomass ocean thermal energy, and tidal and geothermal energy. The main emphasis of the text is on the sun and the solar energy that it yields. Discussions on the sun's composition and the relationship between the earth, sun and atmosphere are provided. Insolation, active and passive solar systems, and solar collectors are the subtopics included under solar energy. (BCS)

The solar probe and coronal dynamics

NASA Technical Reports Server (NTRS)

Belcher, J.; Heinemann, M.; Goodrich, C.

1978-01-01

The discovery of coronal holes led to basic changes in ideas about the structure of the low corona and its expansion into the solar wind. The nature of the energy flux is not understood. Current ideas include enhanced thermal conductivities, extended MHD wave heating, and wave momentum transfer, all in rapidly diverging geometries. There is little feel for the relative importance of these processes. The Solar Probe, with its penetration deep into the solar corona, could lead to observational constraints on their relative importance, and thus to an understanding of the origin of the solar wind. Observations from the Solar Probe will also bear on such questions as to whether small scale "intrastream" structure is common close to the Sun in open field-line regions, whether the properties of the wind are pronouncedly different over closed and open field-line regions at five solar radii, and many others. The resolution of these questions requires measurements of the magnetic field and of the proton and electron distribution functions.

A Study of the Solar Wind-Magnetosphere Coupling Using Neural Networks

NASA Astrophysics Data System (ADS)

Wu, Jian-Guo; Lundstedt, Henrik

1996-12-01

The interaction between solar wind plasma and interplanetary magnetic field (IMF) and Earth's magnetosphere induces geomagnetic activity. Geomagnetic storms can cause many adverse effects on technical systems in space and on the Earth. It is therefore of great significance to accurately predict geomagnetic activity so as to minimize the amount of disruption to these operational systems and to allow them to work as efficiently as possible. Dynamic neural networks are powerful in modeling the dynamics encoded in time series of data. In this study, we use partially recurrent neural networks to study the solar wind-magnetosphere coupling by predicting geomagnetic storms (as measured by the Dstindex) from solar wind measurements. The solar wind, the IMF and the geomagnetic index Dst data are hourly averaged and read from the National Space Science Data Center's OMNI database. We selected these data from the period 1963 to 1992, which cover 10552h and contain storm time periods 9552h and quiet time periods 1000h. The data are then categorized into three data sets: a training set (6634h), across-validation set (1962h), and a test set (1956h). The validation set is used to determine where the training should be stopped whereas the test set is used for neural networks to get the generalization capability (the out-of-sample performance). Based on the correlation analysis between the Dst index and various solar wind parameters (including various combinations of solar wind parameters), the best coupling functions can be found from the out-of-sample performance of trained neural networks. The coupling functions found are then used to forecast geomagnetic storms one to several hours in advance. The comparisons are made on iterating the single-step prediction several times and on making a non iterated, direct prediction. Thus, we will present the best solar wind-magnetosphere coupling functions and the corresponding prediction results. Interesting Links: Lund Space Weather and AI Center

IMPRINTS OF EXPANSION ON THE LOCAL ANISOTROPY OF SOLAR WIND TURBULENCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verdini, Andrea; Grappin, Roland

2015-08-01

We study the anisotropy of II-order structure functions (SFs) defined in a frame attached to the local mean field in three-dimensional (3D) direct numerical simulations of magnetohydrodynamic turbulence, with the solar wind expansion both included and not included. We simulate spacecraft flybys through the numerical domain by taking increments along the radial (wind) direction that form an angle of 45° with the ambient magnetic field. We find that only when expansion is taken into account do the synthetic observations match the 3D anisotropy observed in the solar wind, including the change of anisotropy with scale. Our simulations also show thatmore » the anisotropy changes dramatically when considering increments oblique to the radial directions. Both results can be understood by noting that expansion reduces the radial component of the magnetic field at all scales, thus confining fluctuations in the plane perpendicular to the radial. Expansion is thus shown to affect not only the (global) spectral anisotropy, but also the local anisotropy of second-order SF by influencing the distribution of the local mean field, which enters this higher-order statistics.« less

Western Wind and Solar Integration Study | Grid Modernization | NREL

Science.gov Websites

Western Wind and Solar Integration Study Western Wind and Solar Integration Study Can we integrate large amounts of wind and solar energy into the electric power system of the West? That's the question explored by the Western Wind and Solar Integration Study, one of the largest such regional studies to date

Analysis of Surface Charging for a Candidate Solar Sail Mission Using NASCAP-2K

NASA Technical Reports Server (NTRS)

Parker, Linda Neergaard; Minow, Joseph L.; Davis, V. A.; Mandell, Myron; Gardner, Barbara

2005-01-01

The characterization of the electromagnetic interaction for a solar sail in the solar wind environment and identification of viable charging mitigation strategies are critical solar sail mission design tasks. Spacecraft charging has important implications both for science applications and for lifetime and reliability issues of sail propulsion systems. To that end, surface charging calculations of a candidate 150-meter-class solar sail spacecraft for the 0.5 AU solar polar and 1.9 AU LI solar wind environments are performed. A model of the spacecraft with candidate materials having appropriate electrical properties is constructed using Object Toolkit. The spacecraft charging analysis is performed using Nascap-2k. the NASA/AFRL sponsored spacecraft charging analysis tool. Nominal and atypical solar wind environments appropriate for the 0.5 AU and 1.0 AU missions are used to establish current collection of solar wind ions and electrons. Finally, a geostationary orbit environment case is included to demonstrate a bounding example of extreme (negative) charging of a solar sail spacecraft. Results from the charging analyses demonstrate that minimal differential potentials (and resulting threat of electrostatic discharge) occur when the spacecraft is constructed entirely of conducting materials, as anticipated from standard guidelines for mitigation of spacecraft charging issues. Examples with dielectric materials exposed to the space environment exhibit differential potentials ranging from a few volts to extreme potentials in the kilovolt range.

Analysis of Surface Charging for a Candidate Solar Sail Mission Using Nascap-2k

NASA Technical Reports Server (NTRS)

Parker, Linda Neergaard; Minow, Joseph I.; Davis, Victoria; Mandell, Myron; Gardner, Barbara

2005-01-01

The characterization of the electromagnetic interaction for a solar sail in the solar wind environment and identification of viable charging mitigation strategies are critical solar sail mission design task. Spacecraft charging has important implications both for science applications and for lifetime and reliability issues of sail propulsion systems. To that end, surface charging calculations of a candidate 150-meter-class solar sail spacecraft for the 0.5 AU solar polar and 1.0 AU L1 solar wind environments are performed. A model of the spacecraft with candidate materials having appropriate electrical properties is constructed using Object Toolkit. The spacecraft charging analysis is performed using Nascap-2k, the NASA/AFRL sponsored spacecraft charging analysis tool. Nominal and atypical solar wind environments appropriate for the 0.5 AU and 1.0 AU missions are used to establish current collection of solar wind ions and electrons. Finally, a geostationary orbit environment case is included to demonstrate a bounding example of extreme (negative) charging of a solar sail spacecraft. Results from the charging analyses demonstrate that minimal differential potentials (and resulting threat of electrostatic discharge) occur when the spacecraft is constructed entirely of conducting materials, as anticipated from standard guidelines for mitigation of spacecraft charging issues. Examples with dielectric materials exposed to the space environment exhibit differential potentials ranging from a few volts to extreme potentials in the kilovolt range.

Ensemble downscaling in coupled solar wind-magnetosphere modeling for space weather forecasting

PubMed Central

Owens, M J; Horbury, T S; Wicks, R T; McGregor, S L; Savani, N P; Xiong, M

2014-01-01

Advanced forecasting of space weather requires simulation of the whole Sun-to-Earth system, which necessitates driving magnetospheric models with the outputs from solar wind models. This presents a fundamental difficulty, as the magnetosphere is sensitive to both large-scale solar wind structures, which can be captured by solar wind models, and small-scale solar wind “noise,” which is far below typical solar wind model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical “downscaling” of solar wind model results prior to their use as input to a magnetospheric model. As magnetospheric response can be highly nonlinear, this is preferable to downscaling the results of magnetospheric modeling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8 h filter, then add small-scale structure back in through the addition of random noise with the observed spectral characteristics. Here we use a very simple parameterization of noise based upon the observed probability distribution functions of solar wind parameters, but more sophisticated methods will be developed in the future. An ensemble of results from the simple downscaling scheme are tested using a model-independent method and shown to add value to the magnetospheric forecast, both improving the best estimate and quantifying the uncertainty. We suggest a number of features desirable in an operational solar wind downscaling scheme. Key Points Solar wind models must be downscaled in order to drive magnetospheric models Ensemble downscaling is more effective than deterministic downscaling The magnetosphere responds nonlinearly to small-scale solar wind fluctuations PMID:26213518

How Reliable Is the Prediction of Solar Wind Background?

NASA Astrophysics Data System (ADS)

Jian, Lan K.; MacNeice, Peter; Taktakishvili, Aleksandre; Odstrcil, Dusan; Jackson, Bernard; Yu, Hsiu-Shan; Riley, Pete; Sokolov, Igor

2015-04-01

The prediction of solar wind background is a necessary part of space weather forecasting. Multiple coronal and heliospheric models have been installed at the Community Coordinated Modeling Center (CCMC) to produce the solar wind, including the Wang-Sheely-Arge (WSA)-Enlil model, MHD-Around-a-Sphere (MAS)-Enlil model, Space Weather Modeling Framework (SWMF), and heliospheric tomography using interplanetary scintillation (IPS) data. By comparing the modeling results with the OMNI data over 7 Carrington rotations in 2007, we have conducted a third-party validation of these models for the near-Earth solar wind. This work will help the models get ready for the transition from research to operation. Besides visual comparison, we have quantitatively assessed the models’ capabilities in reproducing the time series and statistics of solar wind parameters. Using improved algorithms, we have identified magnetic field sector boundaries (SBs) and slow-to-fast stream interaction regions (SIRs) as focused structures. The success rate of capturing them and the time offset vary largely with models. For this period, the 2014 version of MAS-Enlil model works best for SBs, and the heliospheric tomography works best for SIRs. General strengths and weaknesses for each model are identified to provide an unbiased reference to model developers and users.

Does magnetic storm generation depend on the solar wind type?

NASA Astrophysics Data System (ADS)

Nikolaeva, N. S.; Yermolaev, Yu. I.; Lodkina, I. G.; Yermolaev, M. Yu.

2017-09-01

The purpose of this work is to draw the reader's attention to the problem of possible differences in the generation of magnetic storms by different large-scale solar wind types: corotating interaction regions (CIRs), Sheaths, and interplanetary coronal mass ejections (ICMEs), including magnetic clouds (MCs) and Ejecta. We recently showed that the description of relationships between interplanetary conditions and Dst and Dst* indices with the modified formula by Burton et al. gives an 50% higher efficiency of storm generation by Sheath and CIR than that by ICME. Many function couplings (FCs) between different interplanetary parameters and the magnetosphere state have been suggested in the literature; however, they have not been analyzed for different solar wind types. In this work, we study the generation efficiency of the main phase of a storm by different solar wind streams with the use of 12 FCs on the basis of OMNI data for 1976-2000. The results show that the Sheath has the highest efficiency for most FCs, and MC is the least efficient, and this result corresponds to our previous results. The reliability of the results and possible causes of differences for different FCs and solar wind types are to be studied further.

A GENERALIZED TWO-COMPONENT MODEL OF SOLAR WIND TURBULENCE AND AB INITIO DIFFUSION MEAN-FREE PATHS AND DRIFT LENGTHSCALES OF COSMIC RAYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiengarten, T.; Fichtner, H.; Kleimann, J.

2016-12-10

We extend a two-component model for the evolution of fluctuations in the solar wind plasma so that it is fully three-dimensional (3D) and also coupled self-consistently to the large-scale magnetohydrodynamic equations describing the background solar wind. The two classes of fluctuations considered are a high-frequency parallel-propagating wave-like piece and a low-frequency quasi-two-dimensional component. For both components, the nonlinear dynamics is dominanted by quasi-perpendicular spectral cascades of energy. Driving of the fluctuations by, for example, velocity shear and pickup ions is included. Numerical solutions to the new model are obtained using the Cronos framework, and validated against previous simpler models. Comparing results frommore » the new model with spacecraft measurements, we find improved agreement relative to earlier models that employ prescribed background solar wind fields. Finally, the new results for the wave-like and quasi-two-dimensional fluctuations are used to calculate ab initio diffusion mean-free paths and drift lengthscales for the transport of cosmic rays in the turbulent solar wind.« less

78 FR 76609 - Genesis Solar, LLC; NRG Delta LLC; Mountain View Solar, LLC; Pheasant Run Wind, LLC; Pheasant Run...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-18

... Delta LLC; Mountain View Solar, LLC; Pheasant Run Wind, LLC; Pheasant Run Wind II, LLC; Tuscola Wind II, LLC; Mountain Wind Power, LLC; Mountain Wind Power II, LLC; Summerhaven Wind, LP; Notice of...

Benefits of Colocating Concentrating Solar Power and Wind

DOE PAGES

Sioshansi, Ramteen; Denholm, Paul

2013-09-16

Here, we analyze the potential benefits of colocating wind and concentrating solar power (CSP) plants in the southwestern U.S. Using a location in western Texas as a case study, we demonstrate that such a deployment strategy can improve the capacity factor of the combined plant and the associated transmission investment. This is because of two synergies between wind and CSP: 1) the negative correlation between real-time wind and solar resource availability and 2) the use of low-cost high-efficiency thermal energy storage in CSP. The economic tradeoff between transmission and system performance is highly sensitive to CSP and transmission costs. Finally,more » we demonstrate that a number of deployment configurations, which include up to 67% CSP, yield a positive net return on investment.« less

Mass-loading of the solar wind at 67P/Churyumov-Gerasimenko. Observations and modelling

NASA Astrophysics Data System (ADS)

Behar, E.; Lindkvist, J.; Nilsson, H.; Holmström, M.; Stenberg-Wieser, G.; Ramstad, R.; Götz, C.

2016-11-01

Context. The first long-term in-situ observation of the plasma environment in the vicinity of a comet, as provided by the European Rosetta spacecraft. Aims: Here we offer characterisation of the solar wind flow near 67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus activity. We also aim to quantify and interpret the deflection and deceleration of the flow expected from ionization of neutral cometary particles within the undisturbed solar wind. Methods: We have analysed in situ ion and magnetic field data and combined this with hybrid modeling of the interaction between the solar wind and the comet atmosphere. Results: The solar wind deflection is increasing with decreasing heliocentric distances, and exhibits very little deceleration. This is seen both in observations and in modeled solar wind protons. According to our model, energy and momentum are transferred from the solar wind to the coma in a single region, centered on the nucleus, with a size in the order of 1000 km. This interaction affects, over larger scales, the downstream modeled solar wind flow. The energy gained by the cometary ions is a small fraction of the energy available in the solar wind. Conclusions: The deflection of the solar wind is the strongest and clearest signature of the mass-loading for a small, low-activity comet, whereas there is little deceleration of the solar wind.

Magnetopause Standoff Position Changes and Geosynchronous Orbit Crossings: Models and Observations

NASA Astrophysics Data System (ADS)

Collado-Vega, Y. M.; Rastaetter, L.; Sibeck, D. G.

2017-12-01

The Earth's magnetopause is the boundary that mostly separates the solar wind with the Earth's magnetosphere. Its location has been studied and estimated via simulation models, observational data and empirical models. This research aims to study the changes of the magnetopause standoff location due to different solar wind conditions using a combination of all the different methods. We will use the Run-On-Request capabilities within the MHD models available from the Community Coordinated Modeling Center (CCMC) at NASA Goddard Space Flight Center, specifically BATS-R-US (SWMF), OpenGGCM, LFM and GUMICS models. The magnetopause standoff position prediction and response time to the solar wind changes will then be compared to results from available empirical models (e.g. Shue et al. 1998), and to THEMIS, Cluster, Geotail and MMS missions magnetopause crossing observations. We will also use times of extreme solar wind conditions where magnetopause crossings have been observed by the GOES satellites. Rigorous analysis/comparison of observations and empirical models is critical in determining magnetosphere dynamics for model validation. This research goes also hand in hand with the efforts of the working group at the CCMC/LWS International Forum for Space Weather Capabilities Assessment workshop that aims to analyze different events to define metrics for model-data comparison. Preliminary results of this particular research show that there are some discrepancies between the MHD models standoff positions of the dayside magnetopause for the same solar wind conditions that include an increase in solar wind dynamic pressure and a step function in the IMF Bz component. In cases of nominal solar wind conditions, it has been observed that the models do mostly agree with the observational data from the different satellite missions.

OVATION Prime -2013: Solar Wind Driven Precipitation Model Extended to Higher Geomagnetic Activity Levels (Invited)

NASA Astrophysics Data System (ADS)

Newell, P. T.; Liou, K.; Zhang, Y.; Paxton, L.; Sotirelis, T.; Mitchell, E. J.

2013-12-01

OVATION Prime is an auroral precipitation model parameterized by solar wind driving. Distinguishing features of the model include an optimized solar wind-magnetosphere coupling function (dΦMP/dt) which predicts auroral power far better than Kp or other traditional parameters, the separation of aurora into categories (diffuse aurora, monoenergetic, broadband, and ion), the inclusion of seasonal variations, and separate parameter fits for each MLATxMLT bin, thus permitting each type of aurora and each location to have differing responses to season and solar wind input (as indeed they do). We here introduce OVATION Prime-2013, an upgrade to the 2008 version currently widely available. The most notable advantage of OP-2013 is that it uses UV images from the GUVI instrument on the satellite TIMED for high disturbance levels (dΦMP/dt > 12,000 (nT2/3 (km/s)4/3 which roughly corresponds to Kp = 5+ or 6-). The range of validity is thought to be about 0 < dΦMP/dt = 30000 (say Kp = 8 or 8+). Other upgrades include a reduced susceptibility to salt and pepper noise, and smoother interpolation across the postmidnight data gap. We will also provide a comparison of the advantages and disadvantages of other current precipitation models, especially OVATION-SuperMAG, which produces particularly good estimates for total auroral power, at the expense of working best on an historical basis. OVATION Prime-2013, for high solar wind driving, as TIMED GUVI data takes over from DMSP

Numerical simulation of wind loads on solar panels

NASA Astrophysics Data System (ADS)

Su, Kao-Chun; Chung, Kung-Ming; Hsu, Shu-Tsung

2018-05-01

Solar panels mounted on the roof of a building or ground are often vulnerable to strong wind loads. This study aims to investigate wind loads on solar panels using computational fluid dynamic (CFD). The results show good agreement with wind tunnel data, e.g. the streamwise distribution of mean surface pressure coefficient of a solar panel. Wind uplift for solar panels with four aspect ratios is evaluated. The effect of inclined angle and clearance (or height) of a solar panel is addressed. It is found that wind uplift of a solar panel increases when there is an increase in inclined angle and the clearance above ground shows an opposite effect.

Coronal magnetic fields and the solar wind

NASA Technical Reports Server (NTRS)

Newkirk, G., Jr.

1972-01-01

Current information is presented on coronal magnetic fields as they bear on problems of the solar wind. Both steady state fields and coronal transient events are considered. A brief critique is given of the methods of calculating coronal magnetic fields including the potential (current free) models, exact solutions for the solar wind and field interaction, and source surface models. These solutions are compared with the meager quantitative observations which are available at this time. Qualitative comparisons between the shapes of calculated magnetic field lines and the forms visible in the solar corona at several recent eclipses are displayed. These suggest that: (1) coronal streamers develop above extended magnetic arcades which connect unipolar regions of opposite polarity; and (2) loops, arches, and rays in the corona correspond to preferentially filled magnetic tubes in the approximately potential field.

Improvement of background solar wind predictions

NASA Astrophysics Data System (ADS)

Dálya, Zsuzsanna; Opitz, Andrea

2016-04-01

In order to estimate the solar wind properties at any heliospheric positions propagation tools use solar measurements as input data. The ballistic method extrapolates in-situ solar wind observations to the target position. This works well for undisturbed solar wind, while solar wind disturbances such as Corotating Interaction Regions (CIRs) and Coronal Mass Ejections (CMEs) need more consideration. We are working on dedicated ICME lists to clean these signatures from the input data in order to improve our prediction accuracy. These ICME lists are created from several heliospheric spacecraft measurements: ACE, WIND, STEREO, SOHO, MEX and VEX. As a result, we are able to filter out these events from the time series. Our corrected predictions contribute to the investigation of the quiet solar wind and space weather studies.

Microphysics of Waves and Instabilities in the Solar Wind and Their Macro Manifestations in the Corona and Interplanetary Space

NASA Technical Reports Server (NTRS)

Habbal, Shadia Rifai

2005-01-01

Investigations of the physical processes responsible for coronal heating and the acceleration of the solar wind were pursued with the use of our recently developed 2D MHD solar wind code and our 1D multifluid code. In particular, we explored: (1) the role of proton temperature anisotropy in the expansion of the solar (2) the role of plasma parameters at the coronal base in the formation of high (3) a three-fluid model of the slow solar wind (4) the heating of coronal loops (5) a newly developed hybrid code for the study of ion cyclotron resonance in wind, speed solar wind streams at mid-latitudes, the solar wind.

Theoretical studies of the solar atmosphere and interstellar pickup ions

NASA Technical Reports Server (NTRS)

1994-01-01

Solar atmosphere research activities are summarized. Specific topics addressed include: (1) coronal mass ejections and related phenomena; (2) parametric instabilities of Alfven waves; (3) pickup ions in the solar wind; and (4) cosmic rays in the outer heliosphere. Also included is a list of publications covering the following topics: catastrophic evolution of a force-free flux rope; maximum energy release in flux-rope models of eruptive flares; sheet approximations in models of eruptive flares; material ejection, motions of loops and ribbons of two-ribbon flares; dispersion relations for parametric instabilities of parallel-propagating; parametric instabilities of parallel-propagating Alfven waves; beat, modulation, and decay instabilities of a circularly-polarized Alfven wave; effects of time-dependent photoionization on interstellar pickup helium; observation of waves generated by the solar wind pickup of interstellar hydrogen ions; ion thermalization and wave excitation downstream of the quasi-perpendicular bowshock; ion cyclotron instability and the inverse correlation between proton anisotrophy and proton beta; and effects of cosmic rays and interstellar gas on the dynamics of a wind.

11- and 22-year variations of the cosmic ray density and of the solar wind speed

NASA Technical Reports Server (NTRS)

Chirkov, N. P.

1985-01-01

Cosmic ray density variations for 17-21 solar activity cycles and the solar wind speed for 20-21 events are investigated. The 22-year solar wind speed recurrence was found in even and odd cycles. The 22-year variations of cosmic ray density were found to be opposite that of solar wind speed and solar activity. The account of solar wind speed in 11-year variations significantly decreases the modulation region of cosmic rays when E = 10-20 GeV.

Correlations between solar wind parameters and auroral kilometric radiation intensity

NASA Technical Reports Server (NTRS)

Gallagher, D. L.; Dangelo, N.

1981-01-01

The relationship between solar wind properties and the influx of energy into the nightside auroral region as indicated by the intensity of auroral kilometric radiation is investigated. Smoothed Hawkeye satellite observations of auroral radiation at 178, 100 and 56.2 kHz for days 160 through 365 of 1974 are compared with solar wind data from the composite Solar Wind Plasma Data Set, most of which was supplied by the IMP-8 spacecraft. Correlations are made between smoothed daily averages of solar wind ion density, bulk flow speed, total IMF strength, electric field, solar wind speed in the southward direction, solar wind speed multiplied by total IMF strength, the substorm parameter epsilon and the Kp index. The greatest correlation is found between solar wind bulk flow speed and auroral radiation intensity, with a linear correlation coefficient of 0.78 for the 203 daily averages examined. A possible mechanism for the relationship may be related to the propagation into the nightside magnetosphere of low-frequency long-wavelength electrostatic waves produced in the magnetosheath by the solar wind.

Marshall Space Flight Center's Solar Wind Facility

NASA Technical Reports Server (NTRS)

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

2017-01-01

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

Designing a sun-pointing Faraday cup for solar probe plus

NASA Astrophysics Data System (ADS)

Case, A. W.; Kasper, J. C.; Daigneau, P. S.; Caldwell, D.; Freeman, M.; Gauron, T.; Maruca, B. A.; Bookbinder, J.; Korreck, K. E.; Cirtain, J. W.; Effinger, M. E.; Halekas, J. S.; Larson, D. E.; Lazarus, A. J.; Stevens, M. L.; Taylor, E. R.; Wright, K. H., Jr.

2013-06-01

The NASA Solar Probe Plus (SPP) mission will be the first spacecraft to pass through the sub-Alfvénic solar corona. The objectives of the mission are to trace the flow of energy that heats and accelerates the solar corona and solar wind, to determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind, and to explore mechanisms that accelerate and transport energetic particles. The Solar Wind Electrons, Alphas, and Protons (SWEAP) Investigation instrument suite on SPP will measure the bulk solar wind conditions in the inner heliosphere. SWEAP consists of the Solar Probe Cup (SPC), a sun-pointing Faraday Cup, and the Solar Probe ANalyzers (SPAN), a set of 3 electrostatic analyzers that will reside in the penumbra of SPP's thermal protection system and measure solar wind ions and electrons. SPP is scheduled to launch in 2018 into an equatorial solar orbit where a sequence of Venus gravity assists will gradually lower its closest solar approach to within 9.5 solar radii (RS) of the center of the Sun. The photon flux at 9.5 RS is more than 500 times greater than at 1 AU and therefore presents a design challenge for SPC, which will point directly at the Sun. SPC is derived from the Faraday cup instruments successfully flown on spacecraft from the beginning of the space age, but updated with high temperature materials to operate through the solar encounters. Current work includes both instrument design and the development of a testing approach capable of demonstrating adequate performance in encounter conditions. This paper will briefly discuss the suite as a whole, and then focus on the design and capabilities of SPC. We will also present the planned calibration and characterization of the instrument and the testing required to demonstrate the technological readiness of the design.

Technology Learning Activities. Design Brief--Measuring Inaccessible Distances. Alternative Energy Sources: Designing a Wind Powered Generator. Alternative Energy Sources: Designing a Hot Dog Heater Using Solar Energy.

ERIC Educational Resources Information Center

Technology Teacher, 1991

1991-01-01

These three learning activities are on measuring accessible distances, designing a wind powered generator, and designing a hot dog heater using solar energy. Each activity includes description of context, objectives, list of materials and equipment, challenge to students, and evaluation questions. (SK)

The DSCOVR Solar Wind Mission and Future Space Weather Products

NASA Astrophysics Data System (ADS)

Cash, M. D.; Biesecker, D. A.; Reinard, A. A.

2012-12-01

The Deep Space Climate Observatory (DSCOVR) mission, scheduled for launch in mid-2014, will provide real-time solar wind thermal plasma and magnetic measurements to ensure continuous monitoring for space weather forecasting. DSCOVR will orbit L1 and will serve as a follow-on mission to NASA's Advanced Composition Explorer (ACE), which was launched in 1997. DSCOVR will have a total of six instruments, two of which will provide real-time data necessary for space weather forecasting: a Faraday cup to measure the proton and alpha components of the solar wind, and a triaxial fluxgate magnetometer to measure the magnetic field in three dimensions. Real-time data provided by DSCOVR will include Vx, Vy, Vz, n, T, Bx, By, and Bz. Such real-time L1 data is used in generating space weather applications and products that have been demonstrated to be highly accurate and provide actionable information for customers. We evaluate current space weather products driven by ACE and discuss future products under development for DSCOVR. New space weather products under consideration include: automated shock detection, more accurate L1 to Earth delay time, and prediction of rotations in solar wind Bz within magnetic clouds. Suggestions from the community on product ideas are welcome.

Nasa's Solar Probe Plus Mission and Implications for the Theoretical Understanding of the Heliosphere

NASA Astrophysics Data System (ADS)

Velli, Marco

2012-07-01

Solar Probe Plus (SPP), one of the most challenging missions to understand the origins of the Heliosphere, will carry a payload consisting of plasma and energetic particle detectors, elec- tromagnetic field antennas and magnetometers, and a white light imager, to the unexplored regions extending from 70 to 8.5 solar radii (0.3 to 0.05 AU) from the photosphere of the Sun. Solar Probe Plus's goals are to understand the extended heating of the solar corona and acceleration of the solar wind,the origins of solar wind structures including high and low speed streams, and the origins of energetic particle acceleration in Coronal Mass Ejections and CMEs. In addition, combined measurements from the white light imager and the EM field antennas will allow the first direct measurements of dust deep in the inner solar system. This presentation will provide a broad context for the mission objectives and measurements and illustrate the likely progress SPP will bring to the understanding of the Heliosphere, stellar winds, and the fundamental physics of particle acceleration, reconnection, collisionless shocks and turbulence in space and astrophysical plasmas.

Coronal holes as sources of solar wind

NASA Technical Reports Server (NTRS)

Nolte, J. T.; Krieger, A. S.; Timothy, A. F.; Gold, R. E.; Roelof, E. C.; Vaiana, G.; Lazarus, A. J.; Sullivan, J. D.; Mcintosh, P. S.

1976-01-01

We investigate the association of high-speed solar wind with coronal holes during the Skylab mission by: (1) direct comparison of solar wind and coronal X-ray data; (2) comparison of near-equatorial coronal hole area with maximum solar wind velocity in the associated streams; and (3) examination of the correlation between solar and interplanetary magnetic polarities. We find that all large near-equatorial coronal holes seen during the Skylab period were associated with high-velocity solar wind streams observed at 1 AU.

Analysis of the solar/wind resources in Southern Spain for optimal sizing of hybrid solar-wind power generation systems

NASA Astrophysics Data System (ADS)

Quesada-Ruiz, S.; Pozo-Vazquez, D.; Santos-Alamillos, F. J.; Lara-Fanego, V.; Ruiz-Arias, J. A.; Tovar-Pescador, J.

2010-09-01

A drawback common to the solar and wind energy systems is their unpredictable nature and dependence on weather and climate on a wide range of time scales. In addition, the variation of the energy output may not match with the time distribution of the load demand. This can partially be solved by the use of batteries for energy storage in stand-alone systems. The problem caused by the variable nature of the solar and wind resources can be partially overcome by the use of energy systems that uses both renewable resources in a combined manner, that is, hybrid wind-solar systems. Since both resources can show complementary characteristics in certain location, the independent use of solar or wind systems results in considerable over sizing of the batteries system compared to the use of hybrid solar-wind systems. Nevertheless, to the day, there is no single recognized method for properly sizing these hybrid wind-solar systems. In this work, we present a method for sizing wind-solar hybrid systems in southern Spain. The method is based on the analysis of the wind and solar resources on daily scale, particularly, its temporal complementary characteristics. The method aims to minimize the size of the energy storage systems, trying to provide the most reliable supply.

Heavy ion composition in the inner heliosphere: Predictions for Solar Orbiter

NASA Astrophysics Data System (ADS)

Lepri, S. T.; Livi, S. A.; Galvin, A. B.; Kistler, L. M.; Raines, J. M.; Allegrini, F.; Collier, M. R.; Zurbuchen, T.

2014-12-01

The Heavy Ion Sensor (HIS) on SO, with its high time resolution, will provide the first ever solar wind and surpathermal heavy ion composition and 3D velocity distribution function measurements inside the orbit of Mercury. These measurements will provide us the most in depth examination of the origin, structure and evolution of the solar wind. The near co-rotation phases of the orbiter will enable the most accurate mapping of in-situ structures back to their solar sources. Measurements of solar wind composition and heavy ion kinetic properties enable characterization of the sources, transport mechanisms and acceleration processes of the solar wind. This presentation will focus on the current state of in-situ studies of heavy ions in the solar wind and their implications for the sources of the solar wind, the nature of structure and variability in the solar wind, and the acceleration of particles. Additionally, we will also discuss opportunities for coordinated measurements across the payloads of Solar Orbiter and Solar Probe in order to answer key outstanding science questions of central interest to the Solar and Heliophysics communities.

Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

DOE PAGES

Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; ...

2015-01-01

The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of ⁴He in a collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the solar wind ⁴He depth profile ismore » consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.« less

Charged Particle Environments in Earth's Magnetosphere and their Effects on Space System

NASA Technical Reports Server (NTRS)

Minow, Joseph I.

2009-01-01

This slide presentation reviews information on space radiation environments important to magnetospheric missions including trapped radiation, solar particle events, cosmic rays, and solar winds. It also includes information about ion penetration of the magnetosphere, galactic cosmic rays, solar particle environments, CRRES internal discharge monitor, surface charging and radiation effects.

An investigation of solar wind effects on the evolution of the Martian atmosphere

NASA Technical Reports Server (NTRS)

Luhmann, Janet G.

1994-01-01

This investigation concentrated on the question of how atmosphere escape, related to both photochemistry and the Mars solar wind interaction, may have affected the evolution of Mars' atmosphere over time. The principal investigator and postdoctoral researcher adopted the premise that contemporary escape processes have dominated the losses to space over the past 3.5 billion years, but that the associated loss rates have been modified by solar evolution. A model was constructed for the contemporary escape scenario based on knowledge gained from both Venus in-situ measurements from Pioneer Venus Orbiter and Mars measurements from Phobos-2. Venus provided a valuable second example of a weakly magnetized planet having a similar solar wind interaction where we have more knowledge from observations. The model included photochemical losses from recombining ionospheric molecular ions, scavenging Martian upper atmosphere ('pickup') ions by the solar wind, and sputtering of the atmosphere by reentering pickup ions. The existence of the latter mechanism was realized during the course of the supported investigation, and is now thought by Jakosky and Pepin to explain some of the Martian noble gas isotope ratios.

Effects of interplanetary coronal mass ejections on the transport of nano-dust generated in the inner solar system

NASA Astrophysics Data System (ADS)

O'Brien, Leela; Juhász, Antal; Sternovsky, Zoltan; Horányi, Mihály

2018-07-01

This article reports on an investigation of the effect of interplanetary coronal mass ejections (ICMEs) on the transport and delivery of nano-dust to 1 AU. Charged nanometer-sized dust particles are expected to be generated close to the Sun and interact strongly with the solar wind as well as solar transient events. Nano-dust generated outside of ∼0.2 AU are picked up and transported away from the Sun due to the electromagnetic forces exerted by the solar wind. A numerical model has been developed to calculate the trajectories of nano-dust through their interaction with the solar wind and explore the potential for their detection near Earth's orbit (Juhasz and Horanyi, 2013). Here, we extend the model to include the interaction with interplanetary coronal mass ejections. We report that ICMEs can greatly alter nano-dust trajectories, their transport to 1 AU, and their distribution near Earth's orbit. The smallest nano-dust (<10 nm) can be delivered to 1 AU in high concentration. Thus, the nature of the interaction between nano-dust and ICMEs could potentially be revealed by simultaneous measurements of nano-dust fluxes and solar wind particles/magnetic fields.

The Solar Wind Ion Composition Spectrometer

NASA Technical Reports Server (NTRS)

Gloeckler, G.; Geiss, J.; Balsiger, H.; Bedini, P.; Cain, J. C.; Fisher, J.; Fisk, L. A.; Galvin, A. B.; Gliem, F.; Hamilton, D. C.

1992-01-01

The Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses is designed to determine uniquely the elemental and ionic-charge composition, and the temperatures and mean speeds of all major solar-wind ions, from H through Fe, at solar wind speeds ranging from 175 km/s (protons) to 1280 km/s (Fe(8+)). The instrument, which covers an energy per charge range from 0.16 to 59.6 keV/e in about 13 min, combines an electrostatic analyzer with postacceleration, followed by a time-of-flight and energy measurement. The measurements made by SWICS will have an impact on many areas of solar and heliospheric physics, in particular providing essential and unique information on: (1) conditions and processes in the region of the corona where the solar wind is accelerated; (2) the location of the source regions of the solar wind in the corona; (3) coronal heating processes; (4) the extent and causes of variations in the composition of the solar atmosphere; (5) plasma processes in the solar wind; (6) the acceleration of energetic particles in the solar wind; (7) the thermalization and acceleration of interstellar ions in the solar wind, and their composition; and (8) the composition, charge states, and behavior of the plasma in various regions of the Jovian magnetosphere.

Power Spectra, Power Law Exponents, and Anisotropy of Solar Wind Turbulence at Small Scales

NASA Technical Reports Server (NTRS)

Podesta, J. J.; Roberts, D. A.; Goldstein, M. L.

2006-01-01

The Wind spacecraft provides simultaneous solar wind velocity and magnetic field measurements with 3- second time resolution, roughly an order of magnitude faster than previous measurements, enabling the small scale features of solar wind turbulence to be studied in unprecedented detail. Almost the entire inertial range can now be explored (the inertial range extends from approximately 1 to 10(exp 3) seconds in the spacecraft frame) although the dissipation range of the velocity fluctuations is still out of reach. Improved measurements of solar wind turbulence spectra at 1 AU in the ecliptic plane are presented including spectra of the energy and cross-helicity, the magnetic and kinetic energies, the Alfven ratio, the normalized cross-helicity, and the Elsasser ratio. Some recent observations and theoretical challenges are discussed including the observation that the velocity and magnetic field spectra often show different power law exponents with values close to 3/2 and 5/3, respectively; the energy (kinetic plus magnetic) and cross-helicity often have approximately equal power law exponents with values intermediate between 3/2 and 5/3; and the Alfven ratio, the ratio of the kinetic to magnetic energy spectra, is often a slowly increasing function of frequency increasing from around 0.4 to 1 for frequencies in the inertial range. Differences between high- and low-speed wind are also discussed. Comparisons with phenomenological turbulence theories show that important aspects of the physics are yet unexplained.

Energetic Neutral Atom Imaging of the Lunar Poles and Night-Side

NASA Astrophysics Data System (ADS)

Vorburger, Audrey; Wurz, Peter; Barabash, Stas; Wieser, Martin; Futaana, Yoshifumi; Bhardwaj, Anil; Dhanya, Mb; Asamura, Kazushi

2016-04-01

So far all reported scientific results derived from measurements of the Chandrayaan-1 Energetic Neutral Analyzer (CENA) on board the Indian lunar mission Chandrayaan-1 focused on the sun-lit part of the Moon. Here, for the first time, we present the analysis of the Moon - solar wind interaction in Energetic Neutral Atoms (ENAs) from measurements over the poles and the night-side of the Moon. The Moon, not being protected by a global magnetic field or an atmosphere, is constantly bombarded by solar wind ions. Until recently, it was tacitly assumed that the solar wind ions that impinge onto the lunar surface are almost completely absorbed ( < 1% reflection) by the lunar surface (e.g. Crider and Vondrak [Adv. Space Res., 2002]; Feldman et al. [J. Geophys. Res., 2000]). However, recent observations conducted by the two ENA sensors of NASA's Interstellar Boundary Explorer and by Chandrayaan-1/CENA showed an average global energetic neutral atom (ENA) albedo of 10% - 20% (e.g. McComas et al. [Geophys. Res. Lett., 2009], Wieser et al. [Planet. Space Sci., 2009], Vorburger et al. [J. Geophys. Res., 2013]). In the past 6 years, several studies have closely investigated this solar wind - lunar surface interaction from various viewpoints. The main findings of these studies include (1) the dependency of the hydrogen reflection ratio on the local crustal magnetic fields (e.g., Wieser et al. [Geophys. Res. Lett. ,2010] and Vorburger et al. [J. Geophys. Res., 2012]), (2) the determination of the energy spectra of backscattered neutralized solar wind protons (Futaana et al. [J. Geophys. Res., 2012]) (3) the use of the spectra shape to remotely define an electric potential above a lunar magnetic anomaly (Futaana et al. [Geophys. Res. Lett., 2012]), (4) the favouring of backscattering over forward-scattering of impinging solar wind hydrogen particles (Vorburger et al. [Geophys. Res. Lett., 2011]), (5) the first-ever measurements of sputtered lunar oxygen (Vorburger et al. [J. Geophys. Res., 2012]), (6) the first-ever observation of backscattered solar wind helium (Vorburger et al. [J. Geophys. Res., 2012]), and (7) the determination of the scattering properties of backscattered solar wind hydrogen measured when the Moon transversed Earth's magneto-sheath (Lue et al. [J. Geophys. Res., 2016]). All findings above are based on measurements from the sun-lit side of the Moon's surface, where solar wind particles can impinge freely onto the lunar surface. On the night-side, in contrast, a large scale wake structure is formed as a result of the high absorption of solar wind plasma on the lunar day-side. Very recent ion measurements of Chandrayaan-1's Solar Wind Monitor (SWIM) have revealed the presence of protons in the near-lunar wake, though (Dhanya et al., [Icarus 2016 (submitted)]). The presence of protons in the near lunar wake implies that there is also some sort of solar wind - lunar surface interaction on the lunar night-side. A complete analysis of this interaction will be presented herein.

Plan for Subdividing Genesis Mission Diamond-on-Silicon 60000 Solar Wind Collector

NASA Technical Reports Server (NTRS)

Burkett, Patti J.; Allton, J. A.; Clemett, S. J.; Gonzales, C. P.; Lauer, H. V., Jr.; Nakamura-Messenger, K.; Rodriquez, M. C.; See, T. H.; Sutter, B.

2013-01-01

NASA's Genesis solar wind sample return mission experienced an off nominal landing resulting in broken, albeit useful collectors. Sample 60000 from the collector is comprised of diamond-like-carbon film on a float zone (FZ) silicon wafer substrate Diamond-on-Silicon (DOS), and is highly prized for its higher concentration of solar wind (SW) atoms. A team of scientist at the Johnson Space Center was charged with determining the best, nondestructive and noncontaminating method to subdivide the specimen that would result in a 1 sq. cm subsample for allocation and analysis. Previous work included imaging of the SW side of 60000, identifying the crystallographic orientation of adjacent fragments, and devising an initial cutting plan.

Greening the Grid: Pathways to Integrate 175 Gigawatts of Renewable Energy into India's Electric Grid, Vol. 1 -- National Study, Executive Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Jaquelin

The use of renewable energy (RE) sources, primarily wind and solar generation, is poised to grow significantly within the Indian power system. The Government of India has established a target of 175 gigawatts (GW) of installed RE capacity by 2022, including 60 GW of wind and 100 GW of solar, up from 29 GW wind and 9 GW solar at the beginning of 2017. Thanks to advanced weather and power system modeling made for this project, the study team is able to explore operational impacts of meeting India's RE targets and identify actions that may be favorable for integration.

On the integration of wind and solar energy to provide a total energy supply in the USA

NASA Astrophysics Data System (ADS)

Archer, Cristina; Mills, David; Cheng, Weili; Sloggy, Matthew; Liebig, Edwin; Rhoades, Alan

2010-05-01

This study examines the feasibility of using renewable energy - mostly wind and solar radiation - as the primary source of energy in the USA, under the assumption that a nationwide electric transmission grid is in place. Previous studies have shown that solar or wind alone can power the present U.S. grid on average. Other studies have shown that solar output from California and Texas using energy storage is well correlated with the state energy load on an hour by hour basis throughout the year and with the U.S. national load on a monthly basis. This study explores scenarios for use of wind and solar energy together at the national scale on an hour by hour basis to determine if such a combination is a better match to national seasonal load scenarios than either of the two alone on an hour-by-hour basis. Actual hour by hour national load data from the year 2006 are used as a basis, with some scenarios incorporating vehicle sector electrification and building heating and cooling using electric heat pumps. Hourly wind speed data were calculated at the hub height of 80 m above the ground for the year 2006 at over 150 windy locations in the continental U.S. using an extrapolation technique based on 10-m wind speed measurements and vertical sounding profiles. Using a 1.5 MW wind turbine as benchmark, the hourly wind power production nationwide was determined at all suitable locations. Similarly, the hourly output from solar plants, with and without thermal storage, was calculated based on Ausra's model assuming that the solar production would occur in the Southwest, the area with the greatest solar radiation density in the U.S. Hourly electricity demand for the year 2006 was obtained nationwide from a variety of sources, including the Federal Energy Regulation Commission. Hourly residential heating and cooking, industrial heat processing, and future electrified transportation loads were calculated from monthly and yearly energy consumption data from the Energy Information Administration. Using different scenarios of wind power penetration (between 10% and 120% of the average national electricity and/or energy demand), the remaining hourly electricity and/or energy load was covered by solar thermal electricity produced via the Ausra's innovative linear reflective system, with various amounts of storage. With a 20% redundancy (i.e., an average production of 120% of the demand), a match of ~98% for electric load and ~96% for total energy load were found for the 60%wind-60%solar combination and with 12-hr storage. Work is continuing on improving that match through more sophisticated storage usage strategies and by looking at other options for the few days in the year for which wind and solar might be insufficient.

Space climate implications from substorm frequency

NASA Astrophysics Data System (ADS)

Newell, P. T.; Gjerloev, J. W.; Mitchell, E. J.

2013-10-01

solar wind impacting the Earth varies over a wide range of time scales, driving a corresponding range of geomagnetic activity. Past work has strongly indicated that the rate of merging on the frontside magnetosphere is the most important predictor for magnetospheric activity, especially over a few hours. However, the magnetosphere exhibits variations on other time scales, including UT, seasonal, and solar cycle variations. Much of this geomagnetic variation cannot be reasonably attributed to changes in the solar wind driving—that is, it is not created by the original Russell-McPherron effect or any generalization thereof. In this paper we examine the solar cycle, seasonal, and diurnal effects based upon the frequency of substorm onsets, using a data set of 53,000 substorm onsets. These were identified through the SuperMAG collaboration and span three decades with continuous coverage. Solar cycle variations include a profound minimum in 2009 (448 substorms) and peak in 2003 (3727). The magnitude of this variation (a factor of 8.3) is not explained through variations in estimators of the frontside merging rate (such as dΦMP/dt), even when the more detailed probability distribution functions are examined. Instead, v, or better, n1/2v2 seems to be implicated in the dramatic difference between active and quiet years, even beyond the role of velocity in modulating merging. Moreover, we find that although most substorms are preceded by flux loading (78.5% are above the mean and 83.8% above median solar wind driving), a high solar wind v is almost as important (68.3% above mean, 74.8% above median). This and other evidence suggest that either v or n1/2v2 (but probably not p) plays a strong secondary role in substorm onset. As for the seasonal and diurnal effects, the elliptical nature of the Earth's orbit, which is closest to the Sun in January, leads to a larger solar wind driving (measured by Bs, vBs, or dΦMP/dt) in November, as is confirmed by 22 years of solar wind observations. However, substorms peak in October and March and have a UT dependence best explained by whether a conducting path established by solar illumination exists in at least one hemisphere in the region where substorm onsets typically occur.

Properties of Minor Ions in the Solar Wind and Implications for the Background Solar Wind Plasma

NASA Technical Reports Server (NTRS)

Esser, Ruth; Ling, James (Technical Monitor)

2001-01-01

Ion charge states measured in situ in interplanetary space carry information on the properties of the solar wind plasma in the inner corona where these ion charge states are formed. The goal of the proposed research was to determine solar wind models and coronal observations that are necessary tools for the interpretation of the ion charge state observations made in situ in the solar wind.

Intercalibration and Cross-Correlation of Ace and Wind Solar Wind Data

NASA Technical Reports Server (NTRS)

2003-01-01

This report covers activities funded from October 1, 1998 through September 30, 2002. Two yearly status reports have been filed on this grant, and they are included as Appendix 1. The purpose of this grant was to compare ACE and Wind solar wind parameters when the two spacecraft were near to one another and then to use the intercalibrated parameters to carry out scientific investigations. In September, 2001 a request for a one-year, no-cost extension until September 30, 2002 was submitted and approved. The statement of work for that extension included adjustment of ACE densities below wind speeds of 350 km/s, a study of shock normal orientations using travel time delays between the two spacecraft, comparison of density jumps at shocks, and a study of temperature anisotropies and double streaming to see if such features evolved between the spacecraft.

Global Solar Magnetic Field Organization in the Outer Corona: Influence on the Solar Wind Speed and Mass Flux Over the Cycle

NASA Astrophysics Data System (ADS)

Réville, Victor; Brun, Allan Sacha

2017-11-01

The dynamics of the solar wind depends intrinsically on the structure of the global solar magnetic field, which undergoes fundamental changes over the 11-year solar cycle. For instance, the wind terminal velocity is thought to be anti-correlated with the expansion factor, a measure of how the magnetic field varies with height in the solar corona, usually computed at a fixed height (≈ 2.5 {R}⊙ , the source surface radius that approximates the distance at which all magnetic field lines become open). However, the magnetic field expansion affects the solar wind in a more detailed way, its influence on the solar wind properties remaining significant well beyond the source surface. We demonstrate this using 3D global magnetohydrodynamic (MHD) simulations of the solar corona, constrained by surface magnetograms over half a solar cycle (1989-2001). A self-consistent expansion beyond the solar wind critical point (even up to 10 {R}⊙ ) makes our model comply with observed characteristics of the solar wind, namely, that the radial magnetic field intensity becomes latitude independent at some distance from the Sun, and that the mass flux is mostly independent of the terminal wind speed. We also show that near activity minimum, the expansion in the higher corona has more influence on the wind speed than the expansion below 2.5 {R}⊙ .

The Genesis Mission Solar Wind Collection: Solar-Wind Statistics over the Period of Collection

NASA Technical Reports Server (NTRS)

Barraclough, B. L.; Wiens, R. C.; Steinberg, J. E.; Reisenfeld, D. B.; Neugebauer, M.; Burnett, D. S.; Gosling, J.; Bremmer, R. R.

2004-01-01

The NASA Genesis spacecraft was launched August 8, 2001 on a mission to collect samples of solar wind for 2 years and return them to earth September 8, 2004. Detailed analyses of the solar wind ions implanted into high-purity collection substrates will be carried out using various mass spectrometry techniques. These analyses are expected to determine key isotopic ratios and elemental abundances in the solar wind, and by extension, in the solar photosphere. Further, the photospheric composition is thought to be representative of the solar nebula with a few exceptions, so that the Genesis mission will provide a baseline for the average solar nebula composition with which to compare present-day compositions of planets, meteorites, and asteroids. The collection of solar wind samples is almost complete. Collection began for most substrates in early December, 2001, and is scheduled to be complete on April 2 of this year. It is critical to understand the solar-wind conditions during the collection phase of the mission. For this reason, plasma ion and electron spectrometers are continuously monitoring the solar wind proton density, velocity, temperature, the alpha/proton ratio, and angular distribution of suprathermal electrons. Here we report on the solar-wind conditions as observed by these in-situ instruments during the first half of the collection phase of the mission, from December, 2001 to present.

Reliability and cost/worth evaluation of generating systems utilizing wind and solar energy

NASA Astrophysics Data System (ADS)

Bagen

The utilization of renewable energy resources such as wind and solar energy for electric power supply has received considerable attention in recent years due to adverse environmental impacts and fuel cost escalation associated with conventional generation. At the present time, wind and/or solar energy sources are utilized to generate electric power in many applications. Wind and solar energy will become important sources for power generation in the future because of their environmental, social and economic benefits, together with public support and government incentives. The wind and sunlight are, however, unstable and variable energy sources, and behave far differently than conventional sources. Energy storage systems are, therefore, often required to smooth the fluctuating nature of the energy conversion system especially in small isolated applications. The research work presented in this thesis is focused on the development and application of reliability and economic benefits assessment associated with incorporating wind energy, solar energy and energy storage in power generating systems. A probabilistic approach using sequential Monte Carlo simulation was employed in this research and a number of analyses were conducted with regards to the adequacy and economic assessment of generation systems containing wind energy, solar energy and energy storage. The evaluation models and techniques incorporate risk index distributions and different operating strategies associated with diesel generation in small isolated systems. Deterministic and probabilistic techniques are combined in this thesis using a system well-being approach to provide useful adequacy indices for small isolated systems that include renewable energy and energy storage. The concepts presented and examples illustrated in this thesis will help power system planners and utility managers to assess the reliability and economic benefits of utilizing wind energy conversion systems, solar energy conversion systems and energy storage in electric power systems and provide useful input to the managerial decision process.

Anisotropic Solar Wind Sputtering of the Lunar Surface Induced by Crustal Magnetic Anomalies

NASA Technical Reports Server (NTRS)

Poppe, A. R.; Sarantos, M.; Halekas, J. S.; Delory, G. T.; Saito, Y.; Nishino, M.

2014-01-01

The lunar exosphere is generated by several processes each of which generates neutral distributions with different spatial and temporal variability. Solar wind sputtering of the lunar surface is a major process for many regolith-derived species and typically generates neutral distributions with a cosine dependence on solar zenith angle. Complicating this picture are remanent crustal magnetic anomalies on the lunar surface, which decelerate and partially reflect the solar wind before it strikes the surface. We use Kaguya maps of solar wind reflection efficiencies, Lunar Prospector maps of crustal field strengths, and published neutral sputtering yields to calculate anisotropic solar wind sputtering maps. We feed these maps to a Monte Carlo neutral exospheric model to explore three-dimensional exospheric anisotropies and find that significant anisotropies should be present in the neutral exosphere depending on selenographic location and solar wind conditions. Better understanding of solar wind/crustal anomaly interactions could potentially improve our results.

Observations of micro-turbulence in the solar wind near the sun with interplanetary scintillation

NASA Technical Reports Server (NTRS)

Yamauchi, Y.; Misawa, H.; Kojima, M.; Mori, H.; Tanaka, T.; Takaba, H.; Kondo, T.; Tokumaru, M.; Manoharan, P. K.

1995-01-01

Velocity and density turbulence of solar wind were inferred from interplanetary scintillation (IPS) observations at 2.3 GHz and 8.5 GHz using a single-antenna. The observations were made during September and October in 1992 - 1994. They covered the distance range between 5 and 76 solar radii (Rs). We applied the spectrum fitting method to obtain a velocity, an axial ratio, an inner scale and a power-law spectrum index. We examined the difference of the turbulence properties near the Sun between low-speed solar wind and high-speed solar wind. Both of solar winds showed acceleration at the distance range of 10 - 30 Rs. The radial dependence of anisotropy and spectrum index did not have significant difference between low-speed and high-speed solar winds. Near the sun, the radial dependence of the inner scale showed the separation from the linear relation as reported by previous works. We found that the inner scale of high-speed solar wind is larger than that of low-speed wind.

MAVEN observations of the solar cycle 24 space weather conditions at Mars

NASA Astrophysics Data System (ADS)

Lee, C. O.; Hara, T.; Halekas, J. S.; Thiemann, E.; Chamberlin, P.; Eparvier, F.; Lillis, R. J.; Larson, D. E.; Dunn, P. A.; Espley, J. R.; Gruesbeck, J.; Curry, S. M.; Luhmann, J. G.; Jakosky, B. M.

2017-03-01

The Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has been continuously observing the variability of solar soft X-rays and EUV irradiance, monitoring the upstream solar wind and interplanetary magnetic field conditions and measuring the fluxes of solar energetic ions and electrons since its arrival to Mars. In this paper, we provide a comprehensive overview of the space weather events observed during the first ˜1.9 years of the science mission, which includes the description of the solar and heliospheric sources of the space weather activity. To illustrate the variety of upstream conditions observed, we characterize a subset of the event periods by describing the Sun-to-Mars details using observations from the MAVEN solar Extreme Ultraviolet Monitor, solar energetic particle (SEP) instrument, Solar Wind Ion Analyzer, and Magnetometer together with solar observations using near-Earth assets and numerical solar wind simulation results from the Wang-Sheeley-Arge-Enlil model for some global context of the event periods. The subset of events includes an extensive period of intense SEP electron particle fluxes triggered by a series of solar flares and coronal mass ejection (CME) activity in December 2014, the impact by a succession of interplanetary CMEs and their associated SEPs in March 2015, and the passage of a strong corotating interaction region (CIR) and arrival of the CIR shock-accelerated energetic particles in June 2015. However, in the context of the weaker heliospheric conditions observed throughout solar cycle 24, these events were moderate in comparison to the stronger storms observed previously at Mars.

Solar-wind predictions for the Parker Solar Probe orbit. Near-Sun extrapolations derived from an empirical solar-wind model based on Helios and OMNI observations

NASA Astrophysics Data System (ADS)

Venzmer, M. S.; Bothmer, V.

2018-03-01

Context. The Parker Solar Probe (PSP; formerly Solar Probe Plus) mission will be humanitys first in situ exploration of the solar corona with closest perihelia at 9.86 solar radii (R⊙) distance to the Sun. It will help answer hitherto unresolved questions on the heating of the solar corona and the source and acceleration of the solar wind and solar energetic particles. The scope of this study is to model the solar-wind environment for PSPs unprecedented distances in its prime mission phase during the years 2018 to 2025. The study is performed within the Coronagraphic German And US SolarProbePlus Survey (CGAUSS) which is the German contribution to the PSP mission as part of the Wide-field Imager for Solar PRobe. Aim. We present an empirical solar-wind model for the inner heliosphere which is derived from OMNI and Helios data. The German-US space probes Helios 1 and Helios 2 flew in the 1970s and observed solar wind in the ecliptic within heliocentric distances of 0.29 au to 0.98 au. The OMNI database consists of multi-spacecraft intercalibrated in situ data obtained near 1 au over more than five solar cycles. The international sunspot number (SSN) and its predictions are used to derive dependencies of the major solar-wind parameters on solar activity and to forecast their properties for the PSP mission. Methods: The frequency distributions for the solar-wind key parameters, magnetic field strength, proton velocity, density, and temperature, are represented by lognormal functions. In addition, we consider the velocity distributions bi-componental shape, consisting of a slower and a faster part. Functional relations to solar activity are compiled with use of the OMNI data by correlating and fitting the frequency distributions with the SSN. Further, based on the combined data set from both Helios probes, the parameters frequency distributions are fitted with respect to solar distance to obtain power law dependencies. Thus an empirical solar-wind model for the inner heliosphere confined to the ecliptic region is derived, accounting for solar activity and for solar distance through adequate shifts of the lognormal distributions. Finally, the inclusion of SSN predictions and the extrapolation down to PSPs perihelion region enables us to estimate the solar-wind environment for PSPs planned trajectory during its mission duration. Results: The CGAUSS empirical solar-wind model for PSP yields dependencies on solar activity and solar distance for the solar-wind parameters' frequency distributions. The estimated solar-wind median values for PSPs first perihelion in 2018 at a solar distance of 0.16 au are 87 nT, 340 km s-1, 214 cm-3, and 503 000 K. The estimates for PSPs first closest perihelion, occurring in 2024 at 0.046 au (9.86 R⊙), are 943 nT, 290 km s-1, 2951 cm-3, and 1 930 000 K. Since the modeled velocity and temperature values below approximately 20 R⊙appear overestimated in comparison with existing observations, this suggests that PSP will directly measure solar-wind acceleration and heating processes below 20 R⊙ as planned.

Flowing Plasma Interaction with an Electric Sail Tether Element

NASA Technical Reports Server (NTRS)

Schneider, Todd; Vaughn, Jason; Wright, Kenneth; Anderson, Allen; Stone, Nobie

2017-01-01

Harnessing the power of the solar wind, an Electric Sail, or E-sail, is a relatively new concept that promises to deliver high speed propellant-less propulsion. The electric sail is an invention made in 2006 at the Kumpula Space Centre in Finland by Pekka Janhunen [Janhunen and Sandroos, 2007]. At its core, an electric sail utilizes multiple positively biased tethers which exchange momentum with solar wind protons via the repelling electric field established around each tether, in other words, by reflecting the solar wind protons. Recognizing the solar wind is a plasma, the effective repelling area of each tether is increased significantly by the formation a plasma sheath around each tether. Fig. 1 shows schematically a spacecraft employing an electric sail. The positive voltage bias (greater than10kV) applied to each tether naturally results in electron collection. Therefore, the electric sail concept necessarily includes an electron source (electron gun) to return collected electrons to space and maintain the positive bias of the tether system.

A CME-Driven Solar Wind Disturbance Observed at both Low and High Heliographic Latitudes

NASA Technical Reports Server (NTRS)

Gosling, J. T.; McComas, D. J.; Phillips, J. L.; Pizzo, V. J.; Goldstein, B. E.; Forsyth, R. J.; Lepping, R. P.

1995-01-01

A solar wind disturbance produced by a fast coronal mass ejection, CME, that departed from the Sun on February 20, 1994 was observed in the ecliptic plane at 1 AU by IMP 8 and at high heliographic latitudes at 3.53 AU by Ulysses. In the ecliptic the disturbance included a strong forward shock but no reverse shock, while at high latitudes the disturbance was bounded by a relatively weak forward-reverse shock pair. It is clear that the disturbance in the ecliptic plane was driven primarily by the relative speed between the CME and a slower ambient solar wind ahead, whereas at higher latitudes the disturbance was driven by expansion of the CME. The combined IMP 8 and Ulysses observations thus provide a graphic illustration of how a single fast CME can produce very different types of solar wind disturbances at low and high heliographic latitudes. Simple numerical simulations help explain observed differences at the two spacecraft.

Constraints on the nature of the ancient lunar magnetic field

NASA Technical Reports Server (NTRS)

Goswami, J. N.

1976-01-01

Assuming that the physical properties of solar-wind ions have remained unchanged over the past 4 billion years, the observation of solar-wind ions in lunar breccias with compaction ages greater than 3.2 billion years places constraints on the nature and origin of the ancient lunar magnetic field. Solar-wind ions would not be expected to occur in old lunar breccias if a surface magnetic field of more than 0.03 gauss was present. Several explanations of this phenomenon are consistent with the global lunar dynamo theory of the origin of the lunar dipole field, including a wandering of the lunar dipole axis, late onset of dynamo action, and reversals of the lunar dipole field, producing a long-term field close to zero. Models invoking external field magnetization as the cause of the ancient lunar magnetic field constrain the dipole axis, precluding field reversals, and do not provide an alternative explanation for the observed occurrence of solar-wind ions in lunar breccias.

Multiple Ions Resonant Heating and Acceleration by Alfven/cyclotron Fluctuations in the Solar Wind

NASA Astrophysics Data System (ADS)

Xie, H.; Ofman, L.

2003-12-01

We study the interaction between protons, and multiple minor ions (O5+, He++) and a given cyclotron resonant spectra in coronal hole plasma. One-dimensional hybrid simulations are performed in initially homogeneous, collisionless, magnetized plasma with waves propagating parallel to the background magnetic field. The self-consistent hybrid simulations are used to study how multiple minor species may affect the resonance interaction between a spectrum of waves and the solar wind protons. The results of the simulations provide a clear picture of wave-particle interaction under various coronal conditions, which can explain 1) how multiple minor ions affect the resonant heating and the temperature anisotropy of the solar wind protons by a given wave spectrum; 2) how energy is distributed and transferred among waves and different ion species; 3) the growth and damping of different beam microinstability modes, including both inward and outward waves; 4) the formation of proton double-peak distribution in the solar wind.

The structure of mass-loading shocks. [interaction of solar wind with cometary coma or local interstellar medium using two-fluid model

NASA Technical Reports Server (NTRS)

Zank, G. P.; Khabibrakhmanov, I. KH.; Story, T.

1993-01-01

A new two-fluid model which describes mass loading in the solar wind (e.g., the interaction of the solar wind with a cometary coma or the local interstellar medium) is presented. The self-consistent back-reaction of the mass-loaded ions is included through their effective scattering in low-frequency MHD turbulence and the invocation of a diffusive approximation. Such an approximation has the advantage of introducing self-consistent dissipation coefficients into the governing equations, thereby facilitating the investigation of the internal structure of shocks in mass-loading environments. To illustrate the utility of the new model, we consider the structure of cometary shocks in the hypersonic one-dimensional limit, finding that the incoming solar wind is slowed by both mass loading and the development of a large cometary ion pressure gradient. The shock is broadened and smoothed by the cometary ions with a thickness of the order of the cometary ion diffusion scale.

Changes in the High-Latitude Topside Ionospheric Vertical Electron-Density Profiles in Response to Solar-Wind Perturbations During Large Magnetic Storms

NASA Technical Reports Server (NTRS)

Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir; Truhlik, Vladimir; Wang, Yongli; Arbacher, Becca

2011-01-01

The latest results from an investigation to establish links between solar-wind and topside-ionospheric parameters will be presented including a case where high-latitude topside electron-density Ne(h) profiles indicated dramatic rapid changes in the scale height during the main phase of a large magnetic storm (Dst < -200 nT). These scale-height changes suggest a large heat input to the topside ionosphere at this time. The topside profiles were derived from ISIS-1 digital ionograms obtained from the NASA Space Physics Data Facility (SPDF) Coordinated Data Analysis Web (CDA Web). Solar-wind data obtained from the NASA OMNIWeb database indicated that the magnetic storm was due to a magnetic cloud. This event is one of several large magnetic storms being investigated during the interval from 1965 to 1984 when both solar-wind and digital topside ionograms, from either Alouette-2, ISIS-1, or ISIS-2, are potentially available.

Formation of Heliospheric Arcs of Slow Solar Wind

NASA Technical Reports Server (NTRS)

Higginson, A. K.; Antiochos, S. K.; Devore, C. R.; Wyper, P. F.; Zurbuchen, T. H.

2017-01-01

A major challenge in solar and heliospheric physics is understanding the origin and nature of the so-called slow solar wind. The Sun's atmosphere is divided into magnetically open regions, known as coronal holes, where the plasma streams out freely and fills the solar system, and closed regions, where the plasma is confined to coronal loops. The boundary between these regions extends outward as the heliospheric current sheet (HCS). Measurements of plasma composition strongly imply that much of the slow wind consists of plasma from the closed corona that escapes onto open field lines, presumably by field-line opening or by interchange reconnection. Both of these processes are expected to release closed-field plasma into the solar wind within and immediately adjacent to the HCS. Mysteriously, however, slow wind with closed-field plasma composition is often observed in situ far from the HCS. We use high-resolution, three-dimensional, magnetohydrodynamic simulations to calculate the dynamics of a coronal hole with a geometry that includes a narrow corridor flanked by closed field and is driven by supergranule-like flows at the coronal-hole boundary. These dynamics produce giant arcs of closed-field plasma that originate at the open-closed boundary in the corona, but extend far from the HCS and span tens of degrees in latitude and longitude at Earth. We conclude that such structures can account for the long-puzzling slow-wind observations.

Formation of Heliospheric Arcs of Slow Solar Wind

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higginson, A. K.; Zurbuchen, T. H.; Antiochos, S. K.

A major challenge in solar and heliospheric physics is understanding the origin and nature of the so-called slow solar wind. The Sun’s atmosphere is divided into magnetically open regions, known as coronal holes, where the plasma streams out freely and fills the solar system, and closed regions, where the plasma is confined to coronal loops. The boundary between these regions extends outward as the heliospheric current sheet (HCS). Measurements of plasma composition strongly imply that much of the slow wind consists of plasma from the closed corona that escapes onto open field lines, presumably by field-line opening or by interchangemore » reconnection. Both of these processes are expected to release closed-field plasma into the solar wind within and immediately adjacent to the HCS. Mysteriously, however, slow wind with closed-field plasma composition is often observed in situ far from the HCS. We use high-resolution, three-dimensional, magnetohydrodynamic simulations to calculate the dynamics of a coronal hole with a geometry that includes a narrow corridor flanked by closed field and is driven by supergranule-like flows at the coronal-hole boundary. These dynamics produce giant arcs of closed-field plasma that originate at the open-closed boundary in the corona, but extend far from the HCS and span tens of degrees in latitude and longitude at Earth. We conclude that such structures can account for the long-puzzling slow-wind observations.« less

On the Integration of Wind and Solar Energy to Provide a Total Energy Supply in the U.S

NASA Astrophysics Data System (ADS)

Liebig, E. C.; Rhoades, A.; Sloggy, M.; Mills, D.; Archer, C. L.

2009-12-01

This study examines the feasibility of using renewable energy - mostly wind and solar radiation - as the primary sources of energy in the U.S., under the assumption that a nationwide electric transmission grid is in place. Previous studies have shown that solar output from California and Texas using energy storage is well correlated with the state energy load on an hour by hour basis throughout the year and with the US national load on a monthly basis. Other studies have shown that solar or wind alone can power the present US grid on average. This study explores scenarios for use of wind and solar energy together at the national scale on an hour by hour basis to determine if such a combination is a better match to national seasonal load scenarios than either of the two alone on an hour-by-hour basis. Actual hour by hour national load data from a particular year will be used as a basis, with some scenarios incorporating vehicle sector electrification and building heating and cooling using electric heat pumps. Hydro and geothermal generation can provide additional controllable output, when needed, to fulfill the hourly electricity and/or energy needs. Hourly wind speed data were calculated at the hub height of 80 m above the ground for the year 2006 at over 150 windy locations in the continental US using an extrapolation technique based on 10-m wind speed measurements and vertical sounding profiles. Using a 1.5 MW wind turbine as benchmark, the hourly wind power production nationwide was determined at all locations. Similarly, the hourly output from solar plants, with and without thermal storage, was calculated based on Ausra’s model assuming that the solar production would occur in the Southwest, the area with the greatest solar radiation density in the U.S. Hourly electricity demand for the year 2006 was obtained nationwide from a variety of sources, including the Federal Energy Regulation Commission. Hourly residential heating and cooking, industrial heat processing, and future electrified transportation loads were calculated from monthly energy consumption data from the Energy Information Administration. Using different scenarios of wind power penetration (10%, 20%, 30%, 50%, 80%, 100% of the average national electricity and/or energy demand), the remaining hourly electricity and/or energy load was covered by various combinations of solar, hydro, and geothermal generation. Statistics of the reliability of the various scenarios, as well as details on the area covered by wind and solar farms per each scenario, will be analyzed and presented.

Polar solar wind and interstellar wind properties from interplanetary Lyman-alpha radiation measurements

NASA Technical Reports Server (NTRS)

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

1981-01-01

The analysis of Mariner 10 observations of Lyman-alpha resonance radiation shows an increase of interplanetary neutral hydrogen densities above the solar poles. This increase is caused by a latitudinal variation of the solar wind velocity and/or flux. Using both the Mariner 10 results and other solar wind observations, the values of the solar wind flux and velocity with latitude are determined for several cases of interest. The latitudinal variation of interplanetary hydrogen gas, arising from the solar wind latitudinal variation, is shown to be most pronounced in the inner solar system. From this result it is shown that spacecraft Lyman-alpha observations are more sensitive to the latitudinal anisotropy for a spacecraft location in the inner solar system near the downwind axis.

The Sun and Earth

NASA Technical Reports Server (NTRS)

Gopalswamy, Natchimuthuk

2012-01-01

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

The solar wind-magnetosphere-ionosphere system

PubMed

Lyon

2000-06-16

The solar wind, magnetosphere, and ionosphere form a single system driven by the transfer of energy and momentum from the solar wind to the magnetosphere and ionosphere. Variations in the solar wind can lead to disruptions of space- and ground-based systems caused by enhanced currents flowing into the ionosphere and increased radiation in the near-Earth environment. The coupling between the solar wind and the magnetosphere is mediated and controlled by the magnetic field in the solar wind through the process of magnetic reconnection. Understanding of the global behavior of this system has improved markedly in the recent past from coordinated observations with a constellation of satellite and ground instruments.

Correlating Solar Wind Modulation with Ionospheric Variability at Mars from MEX and MAVEN Observations

NASA Astrophysics Data System (ADS)

Kopf, A. J.; Morgan, D. D.; Halekas, J. S.; Ruhunusiri, S.; Gurnett, D. A.; Connerney, J. E. P.

2017-12-01

The synthesis of observations by the Mars Express and Mars Atmosphere and Volatiles Evolution (MAVEN) spacecraft allows for a unique opportunity to study variability in the Martian ionosphere from multiple perspectives. One major source for this variability is the solar wind. Due to its elliptical orbit which precesses over time, MAVEN periodically spends part of its orbit outside the Martian bow shock, allowing for direct measurements of the solar wind impacting the Martian plasma environment. When the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument aboard Mars Express is simultaneously sounding the ionosphere, the influence from changes in the solar wind can be observed. Previous studies have suggested a positive correlation, connecting ionospheric density to the solar wind proton flux, but depended on Earth-based measurements for solar wind conditions. More recently, research has indicated that observations of ionospheric variability from these two spacecraft can be connected in special cases, such as shock wave impacts or specific solar wind magnetic field orientations. Here we extend this to more general solar wind conditions and examine how changes in the solar wind properties measured by MAVEN instruments correlate with ionospheric structure and dynamics observed simultaneously in MARSIS remote and local measurements.

Does the magnetic expansion factor play a role in solar wind acceleration?

NASA Astrophysics Data System (ADS)

Wallace, S.; Arge, C. N.; Pihlstrom, Y.

2017-12-01

For the past 25+ years, the magnetic expansion factor (fs) has been a parameter used in the calculation of terminal solar wind speed (vsw) in the Wang-Sheeley-Arge (WSA) coronal and solar wind model. The magnetic expansion factor measures the rate of flux tube expansion in cross section between the photosphere out to 2.5 solar radii (i.e., source surface), and is inversely related to vsw (Wang & Sheeley, 1990). Since the discovery of this inverse relationship, the physical role that fs plays in solar wind acceleration has been debated. In this study, we investigate whether fs plays a causal role in determining terminal solar wind speed or merely serves as proxy. To do so, we study pseudostreamers, which occur when coronal holes of the same polarity are near enough to one another to limit field line expansion. Pseudostreamers are of particular interest because despite having low fs, spacecraft observations show that solar wind emerging from these regions have slow to intermediate speeds of 350-550 km/s (Wang et al., 2012). In this work, we develop a methodology to identify pseudostreamers that are magnetically connected to satellites using WSA output produced with ADAPT input maps. We utilize this methodology to obtain the spacecraft-observed solar wind speed from the exact parcel of solar wind that left the pseudostreamer. We then compare the pseudostreamer's magnetic expansion factor with the observed solar wind speed from multiple spacecraft (i.e., ACE, STEREO-A & B, Ulysses) magnetically connected to the region. We will use this methodology to identify several cases ( 20) where spacecraft are magnetically connected to pseudostreamers, and perform a statistical analysis to determine the correlation of fs within pseudostreamers and the terminal speed of the solar wind emerging from them. This work will help determine if fs plays a physical role in the speed of solar wind originating from regions that typically produce slow wind. This work compliments previous case studies of solar wind originating from pseudostreamers (Riley et al., 2015, Riley & Luhmann 2012) and will contribute to identifying the physical properties of solar wind from these regions. Future work will explore the role of fs in modulating the fast solar wind and will involve a similar analysis for cases where spacecraft are deep within coronal holes.

Can We Predict CME Deflections Based on Solar Magnetic Field Configuration Alone?

NASA Astrophysics Data System (ADS)

Kay, C.; Opher, M.; Evans, R. M.

2013-12-01

Accurate space weather forecasting requires knowledge of the trajectory of coronal mass ejections (CMEs), including predicting CME deflections close to the Sun and through interplanetary space. Deflections of CMEs occur due to variations in the background magnetic field or solar wind speed, magnetic reconnection, and interactions with other CMEs. Using our newly developed model of CME deflections due to gradients in the background solar magnetic field, ForeCAT (Kay et al. 2013), we explore the questions: (a) do all simulated CMEs ultimately deflect to the minimum in the background solar magnetic field? (b) does the majority of the deflection occur in the lower corona below 4 Rs? ForeCAT does not include temporal variations in the magnetic field of active regions (ARs), spatial variations in the background solar wind speed, magnetic reconnection, or interactions with other CMEs. Therefore we focus on the effects of the steady state solar magnetic field. We explore two different Carrington Rotations (CRs): CR 2029 (April-May 2005) and CR 2077 (November-December 2008). Little is known about how the density and magnetic field fall with distance in the lower corona. We consider four density models derived from observations (Chen 1996, Mann et al. 2003, Guhathakurta et al. 2006, Leblanc et al. 1996) and two magnetic field models (PFSS and a scaled model). ForeCAT includes drag resulting from both CME propagation and deflection through the background solar wind. We vary the drag coefficient to explore the effect of drag on the deflection at 1 AU.

Power Flow Simulations of a More Renewable California Grid Utilizing Wind and Solar Insolation Forecasting

NASA Astrophysics Data System (ADS)

Hart, E. K.; Jacobson, M. Z.; Dvorak, M. J.

2008-12-01

Time series power flow analyses of the California electricity grid are performed with extensive addition of intermittent renewable power. The study focuses on the effects of replacing non-renewable and imported (out-of-state) electricity with wind and solar power on the reliability of the transmission grid. Simulations are performed for specific days chosen throughout the year to capture seasonal fluctuations in load, wind, and insolation. Wind farm expansions and new wind farms are proposed based on regional wind resources and time-dependent wind power output is calculated using a meteorological model and the power curves of specific wind turbines. Solar power is incorporated both as centralized and distributed generation. Concentrating solar thermal plants are modeled using local insolation data and the efficiencies of pre-existing plants. Distributed generation from rooftop PV systems is included using regional insolation data, efficiencies of common PV systems, and census data. The additional power output of these technologies offsets power from large natural gas plants and is balanced for the purposes of load matching largely with hydroelectric power and by curtailment when necessary. A quantitative analysis of the effects of this significant shift in the electricity portfolio of the state of California on power availability and transmission line congestion, using a transmission load-flow model, is presented. A sensitivity analysis is also performed to determine the effects of forecasting errors in wind and insolation on load-matching and transmission line congestion.

Sources of Geomagnetic Activity during Nearly Three Solar Cycles (1972-2000)

NASA Technical Reports Server (NTRS)

Richardson, I. G.; Cane, H. V.; Cliver, E. W.; White, Nicholas E. (Technical Monitor)

2002-01-01

We examine the contributions of the principal solar wind components (corotating highspeed streams, slow solar wind, and transient structures, i.e., interplanetary coronal mass ejections (CMEs), shocks, and postshock flows) to averages of the aa geomagnetic index and the interplanetary magnetic field (IMF) strength in 1972-2000 during nearly three solar cycles. A prime motivation is to understand the influence of solar cycle variations in solar wind structure on long-term (e.g., approximately annual) averages of these parameters. We show that high-speed streams account for approximately two-thirds of long-term aa averages at solar minimum, while at solar maximum, structures associated with transients make the largest contribution (approx. 50%), though contributions from streams and slow solar wind continue to be present. Similarly, high-speed streams are the principal contributor (approx. 55%) to solar minimum averages of the IMF, while transient-related structures are the leading contributor (approx. 40%) at solar maximum. These differences between solar maximum and minimum reflect the changing structure of the near-ecliptic solar wind during the solar cycle. For minimum periods, the Earth is embedded in high-speed streams approx. 55% of the time versus approx. 35% for slow solar wind and approx. 10% for CME-associated structures, while at solar maximum, typical percentages are as follows: high-speed streams approx. 35%, slow solar wind approx. 30%, and CME-associated approx. 35%. These compositions show little cycle-to-cycle variation, at least for the interval considered in this paper. Despite the change in the occurrences of different types of solar wind over the solar cycle (and less significant changes from cycle to cycle), overall, variations in the averages of the aa index and IMF closely follow those in corotating streams. Considering solar cycle averages, we show that high-speed streams account for approx. 44%, approx. 48%, and approx. 40% of the solar wind composition, aa, and the IMF strength, respectively, with corresponding figures of approx. 22%, approx. 32%, and approx. 25% for CME-related structures, and approx. 33%, approx. 19%, and approx. 33% for slow solar wind.

Solar wind: Internal parameters driven by external source

NASA Technical Reports Server (NTRS)

Chertkov, A. D.

1995-01-01

A new concept interpreting solar wind parameters is suggested. The process of increasing twofold of a moving volume in the solar wind (with energy transfer across its surface which is comparable with its whole internal energy) is a more rapid process than the relaxation for the pressure. Thus, the solar wind is unique from the point of view of thermodynamics of irreversible processes. The presumptive source of the solar wind creation - the induction electric field of the solar origin - has very low entropy. The state of interplanetary plasma must be very far from the thermodynamic equilibrium. Plasma internal energy is contained mainly in non-degenerate forms (plasma waves, resonant plasma oscillations, electric currents). Microscopic oscillating electric fields in the solar wind plasma should be about 1 V/m. It allows one to describe the solar wind by simple dissipative MHD equations with small effective mean free path (required for hydrodynamical description), low value of electrical conductivity combined with very big apparent thermal conductivity (required for observed solar wind acceleration). These internal parameters are interrelated only due to their origin: they are externally driven. Their relation can change during the interaction of solar wind plasma with an obstacle (planet, spacecraft). The concept proposed can be verified by the special electric field measurements, not ruining the primordial plasma state.

Cutting of Gold Foil in the Genesis Laboratory

NASA Image and Video Library

2005-02-15

The facility for storing and examining Genesis solar wind samples consists of two adjacent laboratories. In these laboratories, the cutting of gold foil to be used in the gathering of the solar wind dust aboard the Genesis spacecraft. Views include: The process of cutting gold foil to be used aboard the Genesis spacecraft. The technicians use Gore-Tex suits with filters as to not contaminate the items.

75 FR 75335 - Integration of Variable Energy Resources

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-02

... the facility owner or operator. This includes, for example, wind, solar thermal and photovoltaic, and... Commission recognized that intermittent resources, such as wind power, have a limited ability to control...\\ The Commission therefore exempted wind resources from certain sections of the LGIA and added Appendix...

Transport of solar wind into Earth's magnetosphere through rolled-up Kelvin-Helmholtz vortices.

PubMed

Hasegawa, H; Fujimoto, M; Phan, T-D; Rème, H; Balogh, A; Dunlop, M W; Hashimoto, C; Tandokoro, R

2004-08-12

Establishing the mechanisms by which the solar wind enters Earth's magnetosphere is one of the biggest goals of magnetospheric physics, as it forms the basis of space weather phenomena such as magnetic storms and aurorae. It is generally believed that magnetic reconnection is the dominant process, especially during southward solar-wind magnetic field conditions when the solar-wind and geomagnetic fields are antiparallel at the low-latitude magnetopause. But the plasma content in the outer magnetosphere increases during northward solar-wind magnetic field conditions, contrary to expectation if reconnection is dominant. Here we show that during northward solar-wind magnetic field conditions-in the absence of active reconnection at low latitudes-there is a solar-wind transport mechanism associated with the nonlinear phase of the Kelvin-Helmholtz instability. This can supply plasma sources for various space weather phenomena.

Applying Nyquist's method for stability determination to solar wind observations

NASA Astrophysics Data System (ADS)

Klein, Kristopher G.; Kasper, Justin C.; Korreck, K. E.; Stevens, Michael L.

2017-10-01

The role instabilities play in governing the evolution of solar and astrophysical plasmas is a matter of considerable scientific interest. The large number of sources of free energy accessible to such nearly collisionless plasmas makes general modeling of unstable behavior, accounting for the temperatures, densities, anisotropies, and relative drifts of a large number of populations, analytically difficult. We therefore seek a general method of stability determination that may be automated for future analysis of solar wind observations. This work describes an efficient application of the Nyquist instability method to the Vlasov dispersion relation appropriate for hot, collisionless, magnetized plasmas, including the solar wind. The algorithm recovers the familiar proton temperature anisotropy instabilities, as well as instabilities that had been previously identified using fits extracted from in situ observations in Gary et al. (2016). Future proposed applications of this method are discussed.

Characterizing a Model of Coronal Heating and Solar Wind Acceleration Based on Wave Turbulence.

NASA Astrophysics Data System (ADS)

Downs, C.; Lionello, R.; Mikic, Z.; Linker, J.; Velli, M.

2014-12-01

Understanding the nature of coronal heating and solar wind acceleration is a key goal in solar and heliospheric research. While there have been many theoretical advances in both topics, including suggestions that they may be intimately related, the inherent scale coupling and complexity of these phenomena limits our ability to construct models that test them on a fundamental level for realistic solar conditions. At the same time, there is an ever increasing impetus to improve our spaceweather models, and incorporating treatments for these processes that capture their basic features while remaining tractable is an important goal. With this in mind, I will give an overview of our exploration of a wave-turbulence driven (WTD) model for coronal heating and solar wind acceleration based on low-frequency Alfvénic turbulence. Here we attempt to bridge the gap between theory and practical modeling by exploring this model in 1D HD and multi-dimensional MHD contexts. The key questions that we explore are: What properties must the model possess to be a viable model for coronal heating? What is the influence of the magnetic field topology (open, closed, rapidly expanding)? And can we simultaneously capture coronal heating and solar wind acceleration with such a quasi-steady formulation? Our initial results suggest that a WTD based formulation performs adequately for a variety of solar and heliospheric conditions, while significantly reducing the number of free parameters when compared to empirical heating and solar wind models. The challenges, applications, and future prospects of this type of approach will also be discussed.

On the Role of Interchange Reconnection in the Generation of the Slow Solar Wind

NASA Astrophysics Data System (ADS)

Edmondson, J. K.

2012-11-01

The heating of the solar corona and therefore the generation of the solar wind, remain an active area of solar and heliophysics research. Several decades of in situ solar wind plasma observations have revealed a rich bimodal solar wind structure, well correlated with coronal magnetic field activity. Therefore, the reconnection processes associated with the large-scale dynamics of the corona likely play a major role in the generation of the slow solar wind flow regime. In order to elucidate the relationship between reconnection-driven coronal magnetic field structure and dynamics and the generation of the slow solar wind, this paper reviews the observations and phenomenology of the solar wind and coronal magnetic field structure. The geometry and topology of nested flux systems, and the (interchange) reconnection process, in the context of coronal physics is then explained. Once these foundations are laid out, the paper summarizes several fully dynamic, 3D MHD calculations of the global coronal system. Finally, the results of these calculations justify a number of important implications and conclusions on the role of reconnection in the structural dynamics of the coronal magnetic field and the generation of the solar wind.

Measurement of Damage Profiles from Solar Wind Implantation

NASA Technical Reports Server (NTRS)

McNamara, K. M.; Synowicki, R. A.; Tiwald, T. E.

2007-01-01

NASA's Genesis Mission launched from Cape Canaveral in August of 2001 with the goal of collecting solar wind in ultra-pure materials. The samples were returned to Earth more than three years later for subsequent analysis. Although the solar wind is comprised primarily of protons, it also contains ionized species representing the entire periodic table. The Genesis mission took advantage of the natural momentum of these ionized species to implant themselves in specialized collectors including single crystal Si and SiC. The collectors trapped the solar wind species of interest and sustained significant damage to the surface crystal structure as a result of the ion bombardment. In this work, spectroscopic ellipsometry has been used to evaluate the extent of this damage in Si and SiC samples. These results and models are compared for artificially implanted samples and pristine non-flight material. In addition, the flown samples had accumulated a thin film of molecular contamination as a result of outgassing in flight, and we demonstrate that this layer can be differentiated from the material damage. In addition to collecting bulk solar wind samples (continuous exposure), the Genesis mission actually returned silicon exposed to four different solar wind regimes: bulk, high speed, low speed, and coronal mass ejections. Each of these solar wind regimes varies in energy, but may vary in composition as well. While determining the composition is a primary goal of the mission, we are also interested in the variation in depth and extent of the damage layer as a function of solar wind regime. Here, we examine flight Si from the bulk solar wind regime and compare the results to both pristine and artificially implanted Si. Finally, there were four samples which were mounted in an electrostatic "concentrator" designed to reject a large fraction (>85%) of incoming protons while enhancing the concentration of ions mass 4-28 amu by a factor of at least 20. Two of these samples were single crystal 6H silicon carbide. (The others were polycrystalline CVD diamond and amorphous carbon that were not examined in the work.) The ion damaged SiC samples from the concentrator were studied in comparison to the flight Si from the bulk array to understand differences in the extent of the damage.

Large-scale structures of solar wind and dynamics of parameters in them

NASA Astrophysics Data System (ADS)

Yermolaev, Yuri; Lodkina, Irina; Yermolaev, Michael

2017-04-01

On the basis of OMNI dataset and our catalog of large-scale solar wind (SW) phenomena (see web-site ftp://ftp.iki.rssi.ru/pub/omni/ and paper by Yermolaev et al., 2009) we study temporal profile of interplanetary and magnetospheric parameters in following SW phenomena: interplanetary manifestation of coronal mass ejection (ICME) including magnetic cloud (MC) and Ejecta, Sheath—compression region before ICME and corotating interaction region (CIR)—compression region before high-speed stream (HSS) of solar wind. To take into account a possible influence of other SW types, following sequences of phenomena, which include all typical sequences of non-stationary SW events, are analyzed: (1) SW/ CIR/ SW, (2) SW/ IS/ CIR/ SW, (3) SW/ Ejecta/ SW, (4) SW/ Sheath/Ejecta/ SW, (5) SW/ IS/ Sheath/ Ejecta/ SW, (6) SW/ MC/ SW, (7) SW/Sheath/ MC/ SW, (8) SW/ IS/ Sheath/ MC/ SW (where SW is undisturbed solar wind, and IS is interplanetary shock) (Yermolaev et al., 2015) using the method of double superposed epoch analysis for large numbers of events (Yermolaev et al., 2010). Similarities and distinctions of different SW phenomena depending on neighboring SW types and their geoeffectiveness are discussed. The work was supported by the Russian Science Foundation, projects 16-12-10062. References: Yermolaev, Yu. I., N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev (2009), Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research, , Vol. 47, No. 2, pp. 81-94. Yermolaev, Y. I., N. S. Nikolaeva, I. G. Lodkina, and M. Y. Yermolaev (2010), Specific interplanetary conditions for CIR-induced, Sheath-induced, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis, Ann. Geophys., 28, pp. 2177-2186. Yermolaev, Yu. I., I. G. Lodkina, N. S. Nikolaeva, and M. Yu. Yermolaev (2015), Dynamics of large-scale solar wind streams obtained by the double superposed epoch analysis, J. Geophys. Res. Space Physics, 120, doi:10.1002/2015JA021274.

Genesis Solar Wind Interstream, Coronal Hole and Coronal Mass Ejection Samples: Update on Availability and Condition

NASA Technical Reports Server (NTRS)

Allton, J. H.; Gonzalez, C. P.; Allums, K. K.

2017-01-01

Recent refinement of analysis of ACE/SWICS data (Advanced Composition Explorer/Solar Wind Ion Composition Spectrometer) and of onboard data for Genesis Discovery Mission of 3 regimes of solar wind at Earth-Sun L1 make it an appropriate time to update the availability and condition of Genesis samples specifically collected in these three regimes and currently curated at Johnson Space Center. ACE/SWICS spacecraft data indicate that solar wind flow types emanating from the interstream regions, from coronal holes and from coronal mass ejections are elementally and isotopically fractionated in different ways from the solar photosphere, and that correction of solar wind values to photosphere values is non-trivial. Returned Genesis solar wind samples captured very different kinds of information about these three regimes than spacecraft data. Samples were collected from 11/30/2001 to 4/1/2004 on the declining phase of solar cycle 23. Meshik, et al is an example of precision attainable. Earlier high precision laboratory analyses of noble gases collected in the interstream, coronal hole and coronal mass ejection regimes speak to degree of fractionation in solar wind formation and models that laboratory data support. The current availability and condition of samples captured on collector plates during interstream slow solar wind, coronal hole high speed solar wind and coronal mass ejections are de-scribed here for potential users of these samples.

Perturbed-input-data ensemble modeling of magnetospheric dynamics

NASA Astrophysics Data System (ADS)

Morley, S.; Steinberg, J. T.; Haiducek, J. D.; Welling, D. T.; Hassan, E.; Weaver, B. P.

2017-12-01

Many models of Earth's magnetospheric dynamics - including global magnetohydrodynamic models, reduced complexity models of substorms and empirical models - are driven by solar wind parameters. To provide consistent coverage of the upstream solar wind these measurements are generally taken near the first Lagrangian point (L1) and algorithmically propagated to the nose of Earth's bow shock. However, the plasma and magnetic field measured near L1 is a point measurement of an inhomogeneous medium, so the individual measurement may not be sufficiently representative of the broader region near L1. The measured plasma may not actually interact with the Earth, and the solar wind structure may evolve between L1 and the bow shock. To quantify uncertainties in simulations, as well as to provide probabilistic forecasts, it is desirable to use perturbed input ensembles of magnetospheric and space weather forecasting models. By using concurrent measurements of the solar wind near L1 and near the Earth, we construct a statistical model of the distributions of solar wind parameters conditioned on their upstream value. So that we can draw random variates from our model we specify the conditional probability distributions using Kernel Density Estimation. We demonstrate the utility of this approach using ensemble runs of selected models that can be used for space weather prediction.

Solar Wind Monitoring with SWIM-SARA Onboard Chandrayaan-1

NASA Astrophysics Data System (ADS)

Bhardwaj, A.; Barabash, S.; Sridharan, R.; Wieser, M.; Dhanya, M. B.; Futaana, Y.; Asamura, K.; Kazama, Y.; McCann, D.; Varier, S.; Vijayakumar, E.; Mohankumar, S. V.; Raghavendra, K. V.; Kurian, T.; Thampi, R. S.; Andersson, H.; Svensson, J.; Karlsson, S.; Fischer, J.; Holmstrom, M.; Wurz, P.; Lundin, R.

The SARA experiment aboard the Indian lunar mission Chandrayaan-1 consists of two instruments: Chandrayaan-1 Energetic Neutral Analyzer (CENA) and the SolarWind Monitor (SWIM). CENA will provide measurements of low energy neutral atoms sputtered from lunar surface in the 0.01-3.3 keV energy range by the impact of solar wind ions. SWIM will monitor the solar wind flux precipitating onto the lunar surface and in the vicinity of moon. SWIM is basically an ion-mass analyzer providing energy-per-charge and number density of solar wind ions in the energy range 0.01-15 keV. It has sufficient mass resolution to resolve H+ , He++, He+, O++, O+, and >20 amu, with energy resolution 7% and angular resolution 4:5° × 22:5. The viewing angle of the instrument is 9° × 180°.Mechanically, SWIM consists of a sensor and an electronic board that includes high voltage supply and sensor electronics. The sensor part consists of an electrostatic deflector to analyze the arrival angle of the ions, cylindrical electrostatic analyzer for energy analysis, and the time-of-flight system for particle velocity determination. The total size of SWIM is slightly larger than a credit card and has a mass of 500 g.

Ion Acceleration by Multiple Reflections at Martian Bow Shock

NASA Astrophysics Data System (ADS)

Yamauchi, M.; Futaana, Y.; Fedorov, A.; Frahm, R. A.; Dubinin, E.; Lundin, R.; Sauvaud, J.-A.; Winningham, J. D.; Barabash, S.; Holmström, H.

2012-04-01

The ion mass analyzer (IMA) on board Mars Express revealed bundled structures of ions in the energy domain within a distance of a proton gyroradius from the Martian bow shock. Seven prominent traversals during 2005 were examined when the energy-bunched structure was observed together with pick-up ions of exospheric origin, the latter of which is used to determine the local magnetic field orientation from its circular trajectory in velocity space. These seven traversals include different bow shock configurations: (a) quasi-perpendicular shock with its specular direction of the solar wind more perpendicular to the magnetic field (QT), (b) quasi-perpendicular shock with its specular reflection direction of the solar wind more along the magnetic field (FS), and (c) quasi-parallel (QL) shock. In all seven cases, the velocity components of the energy-bunched structure are consistent with multiple specular reflections of the solar wind at the bow shock up to at least two reflections. The accelerated solar wind ions after two specular reflections have large parallel components with respect to the magnetic field for the QL shock whereas the field-aligned speed is much smaller than the perpendicular speed for the QT shock. The reflected ions escape into the solar wind when and only when the reflection is in the field-aligned direction.

Implications of L1 Observations for Slow Solar Wind Formation by Solar Reconnection

NASA Technical Reports Server (NTRS)

Kepko, L.; Viall, N. M.; Antiochos, S. K.; Lepri, S. T.; Kasper, J. C.; Weberg, M.

2016-01-01

While the source of the fast solar wind is known to be coronal holes, the source of the slow solar wind has remained a mystery. Long time scale trends in the composition and charge states show strong correlations between solar wind velocity and plasma parameters, yet these correlations have proved ineffective in determining the slow wind source. We take advantage of new high time resolution (12 min) measurements of solar wind composition and charge state abundances at L1 and previously identified 90 min quasi periodic structures to probe the fundamental timescales of slow wind variability. The combination of new high temporal resolution composition measurements and the clearly identified boundaries of the periodic structures allows us to utilize these distinct solar wind parcels as tracers of slowwind origin and acceleration. We find that each 90 min (2000 Mm) parcel of slow wind has near-constant speed yet exhibits repeatable, systematic charge state and composition variations that span the entire range of statistically determined slow solar wind values. The classic composition-velocity correlations do not hold on short, approximately hour long, time scales. Furthermore, the data demonstrate that these structures were created by magnetic reconnection. Our results impose severe new constraints on slow solar wind origin and provide new, compelling evidence that the slow wind results from the sporadic release of closed field plasma via magnetic reconnection at the boundary between open and closed flux in the Sun's atmosphere.

Solar and Wind Forecasting | Grid Modernization | NREL

Science.gov Websites

and Wind Forecasting Solar and Wind Forecasting As solar and wind power become more common system operators. An aerial photo of the National Wind Technology Center's PV arrays. Capabilities value of accurate forecasting Wind power visualization to direct questions and feedback during industry

Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus

NASA Astrophysics Data System (ADS)

Kasper, Justin C.; Abiad, Robert; Austin, Gerry; Balat-Pichelin, Marianne; Bale, Stuart D.; Belcher, John W.; Berg, Peter; Bergner, Henry; Berthomier, Matthieu; Bookbinder, Jay; Brodu, Etienne; Caldwell, David; Case, Anthony W.; Chandran, Benjamin D. G.; Cheimets, Peter; Cirtain, Jonathan W.; Cranmer, Steven R.; Curtis, David W.; Daigneau, Peter; Dalton, Greg; Dasgupta, Brahmananda; DeTomaso, David; Diaz-Aguado, Millan; Djordjevic, Blagoje; Donaskowski, Bill; Effinger, Michael; Florinski, Vladimir; Fox, Nichola; Freeman, Mark; Gallagher, Dennis; Gary, S. Peter; Gauron, Tom; Gates, Richard; Goldstein, Melvin; Golub, Leon; Gordon, Dorothy A.; Gurnee, Reid; Guth, Giora; Halekas, Jasper; Hatch, Ken; Heerikuisen, Jacob; Ho, George; Hu, Qiang; Johnson, Greg; Jordan, Steven P.; Korreck, Kelly E.; Larson, Davin; Lazarus, Alan J.; Li, Gang; Livi, Roberto; Ludlam, Michael; Maksimovic, Milan; McFadden, James P.; Marchant, William; Maruca, Bennet A.; McComas, David J.; Messina, Luciana; Mercer, Tony; Park, Sang; Peddie, Andrew M.; Pogorelov, Nikolai; Reinhart, Matthew J.; Richardson, John D.; Robinson, Miles; Rosen, Irene; Skoug, Ruth M.; Slagle, Amanda; Steinberg, John T.; Stevens, Michael L.; Szabo, Adam; Taylor, Ellen R.; Tiu, Chris; Turin, Paul; Velli, Marco; Webb, Gary; Whittlesey, Phyllis; Wright, Ken; Wu, S. T.; Zank, Gary

2016-12-01

The Solar Wind Electrons Alphas and Protons (SWEAP) Investigation on Solar Probe Plus is a four sensor instrument suite that provides complete measurements of the electrons and ionized helium and hydrogen that constitute the bulk of solar wind and coronal plasma. SWEAP consists of the Solar Probe Cup (SPC) and the Solar Probe Analyzers (SPAN). SPC is a Faraday Cup that looks directly at the Sun and measures ion and electron fluxes and flow angles as a function of energy. SPAN consists of an ion and electron electrostatic analyzer (ESA) on the ram side of SPP (SPAN-A) and an electron ESA on the anti-ram side (SPAN-B). The SPAN-A ion ESA has a time of flight section that enables it to sort particles by their mass/charge ratio, permitting differentiation of ion species. SPAN-A and -B are rotated relative to one another so their broad fields of view combine like the seams on a baseball to view the entire sky except for the region obscured by the heat shield and covered by SPC. Observations by SPC and SPAN produce the combined field of view and measurement capabilities required to fulfill the science objectives of SWEAP and Solar Probe Plus. SWEAP measurements, in concert with magnetic and electric fields, energetic particles, and white light contextual imaging will enable discovery and understanding of solar wind acceleration and formation, coronal and solar wind heating, and particle acceleration in the inner heliosphere of the solar system. SPC and SPAN are managed by the SWEAP Electronics Module (SWEM), which distributes power, formats onboard data products, and serves as a single electrical interface to the spacecraft. SWEAP data products include ion and electron velocity distribution functions with high energy and angular resolution. Full resolution data are stored within the SWEM, enabling high resolution observations of structures such as shocks, reconnection events, and other transient structures to be selected for download after the fact. This paper describes the implementation of the SWEAP Investigation, the driving requirements for the suite, expected performance of the instruments, and planned data products, as of mission preliminary design review.

Solar Ion Processing of Itokawa Grains: Reconciling Model Predictions with Sample Observations

NASA Technical Reports Server (NTRS)

Christoffersen, Roy; Keller, L. P.

2014-01-01

Analytical TEM observations of Itokawa grains reported to date show complex solar wind ion processing effects in the outer 30-100 nm of pyroxene and olivine grains. The effects include loss of long-range structural order, formation of isolated interval cavities or "bubbles", and other nanoscale compositional/microstructural variations. None of the effects so far described have, however, included complete ion-induced amorphization. To link the array of observed relationships to grain surface exposure times, we have adapted our previous numerical model for progressive solar ion processing effects in lunar regolith grains to the Itokawa samples. The model uses SRIM ion collision damage and implantation calculations within a framework of a constant-deposited-energy model for amorphization. Inputs include experimentally-measured amorphization fluences, a Pi steradian variable ion incidence geometry required for a rotating asteroid, and a numerical flux-versus-velocity solar wind spectrum.

Solar Wind Characteristics from SOHO-Sun-Ulysses Quadrature Observations

NASA Technical Reports Server (NTRS)

Poletto, Giannina; Suess, Steve T.; Six, N. Frank (Technical Monitor)

2002-01-01

Over the past few years, we have been running SOHO (Solar and Heliospheric Observatory)-Sun-Ulysses quadrature campaigns, aimed at comparing the plasma properties at coronal altitudes with plasma properties at interplanetary distances. Coronal plasma has been observed by SOHO experiments: mainly, we used LASCO (Large Angle and Spectrometric Coronagraph Experiment) data to understand the overall coronal configuration at the time of quadratures and analyzed SUMER (Solar Ultraviolet Measurements of Emitted Radiation), CDS (Coronal Diagnostic Spectrometer) and UVCS (Ultraviolet Coronagraph Spectrometer) data to derive its physical characteristics. At interplanetary distances, SWICS (Solar Wind Ion Composition Spectrometer) and SWOOPS (Solar Wind Observation over the Poles of the Sun) aboard Ulysses provided us with interplanetary plasma data. Here we report on results from some of the campaigns. We notice that, depending on the geometry of the quadrature, i.e. on whether the radial to Ulysses traverses the corona at high or low latitudes, we are able to study different kinds of solar wind. In particular, a comparison between low-latitude and high-latitude wind, allowed us to provide evidence for differences in the acceleration of polar, fast plasma and equatorial, slow plasma: the latter occurring at higher levels and through a more extended region than fast wind. These properties are shared by both the proton and heavy ions outflows. Quadrature observations may provide useful information also on coronal vs. in situ elemental composition. To this end, we analyzed spectra taken in the corona, at altitudes ranging between approx. 1.02 and 2.2 solar radii, and derived the abundances of a number of ions, including oxygen and iron. Values of the O/Fe ratio, at coronal levels, have been compared with measurements of this ratio made by SWICS at interplanetary distances. Our results are compared with previous findings and predictions from modeling efforts.

Global solar magetic field organization in the extended corona: influence on the solar wind speed and density over the cycle.

NASA Astrophysics Data System (ADS)

Réville, V.; Velli, M.; Brun, S.

2017-12-01

The dynamics of the solar wind depends intrinsically on the structure of the global solar magnetic field, which undergoes fundamental changes over the 11yr solar cycle. For instance, the wind terminal velocity is thought to be anti-correlated with the expansion factor, a measure of how the magnetic field varies with height in the solar corona, usually computed at a fixed height (≈ 2.5 Rȯ, the source surface radius which approximates the distance at which all magnetic field lines become open). However, the magnetic field expansion affects the solar wind in a more detailed way, its influence on the solar wind properties remaining significant well beyond the source surface: we demonstrate this using 3D global MHD simulations of the solar corona, constrained by surface magnetograms over half a solar cycle (1989-2001). For models to comply with the constraints provided by observed characteristics of the solar wind, namely, that the radial magnetic field intensity becomes latitude independent at some distance from the Sun (Ulysses observations beyond 1 AU), and that the terminal wind speed is anti-correlated with the mass flux, they must accurately describe expansion beyond the solar wind critical point (even up to 10Rȯ and higher in our model). We also show that near activity minimum, expansion in the higher corona beyond 2.5 Rȯ is actually the dominant process affecting the wind speed. We discuss the consequences of this result on the necessary acceleration profile of the solar wind, the location of the sonic point and of the energy deposition by Alfvén waves.

Mars atmospheric loss to space: Observations of present-day loss and implications for long-term volatile evolution

NASA Astrophysics Data System (ADS)

Jakosky, Bruce; Brain, David; Luhmann, Janet; Grebowsky, Joe

2017-04-01

MAVEN completed its first Mars year of science mapping in October 2016. Results show loss of gas to space by multiple processes, including solar-wind pick-up, sputtering, photochemical loss, and thermal escape, along with their responses to changing solar and solar-wind boundary conditions and to discrete solar events. By understanding the current loss rates and the processes controlling them, we are able to examine the long-term loss to space, including the effects of different solar conditions early in history; in addition, we are able to use stable-isotope ratios to derive the integrated loss to space through time. Preliminary results suggest that loss to space was a dominant, if not the dominant, mechanism that drove the changing climate through time. We will present a framework for analyzing and interpreting the results, along with preliminary results on the extrapolation to long timescales.

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

NASA Astrophysics Data System (ADS)

Sibeck, David G.; Allen, R.; Aryan, H.; Bodewits, D.; Brandt, P.; Branduardi-Raymont, G.; Brown, G.; Carter, J. A.; Collado-Vega, Y. M.; Collier, M. R.; Connor, H. K.; Cravens, T. E.; Ezoe, Y.; Fok, M.-C.; Galeazzi, M.; Gutynska, O.; Holmström, M.; Hsieh, S.-Y.; Ishikawa, K.; Koutroumpa, D.; Kuntz, K. D.; Leutenegger, M.; Miyoshi, Y.; Porter, F. S.; Purucker, M. E.; Read, A. M.; Raeder, J.; Robertson, I. P.; Samsonov, A. A.; Sembay, S.; Snowden, S. L.; Thomas, N. E.; von Steiger, R.; Walsh, B. M.; Wing, S.

2018-06-01

Both heliophysics and planetary physics seek to understand the complex nature of the solar wind's interaction with solar system obstacles like Earth's magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle observations, guided by the predictions of both local and global numerical simulations, and placed in context by observations from far and extreme ultraviolet (FUV, EUV), hard X-ray, and energetic neutral atom imagers (ENA). Each proposed interaction mechanism (e.g., steady or transient magnetic reconnection, local or global magnetic reconnection, ion pick-up, or the Kelvin-Helmholtz instability) generates diagnostic plasma density structures. The significance of each mechanism to the overall interaction (as measured in terms of atmospheric/ionospheric loss at comets, Venus, and Mars or global magnetospheric/ionospheric convection at Earth) remains to be determined but can be evaluated on the basis of how often the density signatures that it generates are observed as a function of solar wind conditions. This paper reviews efforts to image the diagnostic plasma density structures in the soft (low energy, 0.1-2.0 keV) X-rays produced when high charge state solar wind ions exchange electrons with the exospheric neutrals surrounding solar system obstacles. The introduction notes that theory, local, and global simulations predict the characteristics of plasma boundaries such the bow shock and magnetopause (including location, density gradient, and motion) and regions such as the magnetosheath (including density and width) as a function of location, solar wind conditions, and the particular mechanism operating. In situ measurements confirm the existence of time- and spatial-dependent plasma density structures like the bow shock, magnetosheath, and magnetopause/ionopause at Venus, Mars, comets, and the Earth. However, in situ measurements rarely suffice to determine the global extent of these density structures or their global variation as a function of solar wind conditions, except in the form of empirical studies based on observations from many different times and solar wind conditions. Remote sensing observations provide global information about auroral ovals (FUV and hard X-ray), the terrestrial plasmasphere (EUV), and the terrestrial ring current (ENA). ENA instruments with low energy thresholds (˜1 keV) have recently been used to obtain important information concerning the magnetosheaths of Venus, Mars, and the Earth. Recent technological developments make these magnetosheaths valuable potential targets for high-cadence wide-field-of-view soft X-ray imagers. Section 2 describes proposed dayside interaction mechanisms, including reconnection, the Kelvin-Helmholtz instability, and other processes in greater detail with an emphasis on the plasma density structures that they generate. It focuses upon the questions that remain as yet unanswered, such as the significance of each proposed interaction mode, which can be determined from its occurrence pattern as a function of location and solar wind conditions. Section 3 outlines the physics underlying the charge exchange generation of soft X-rays. Section 4 lists the background sources (helium focusing cone, planetary, and cosmic) of soft X-rays from which the charge exchange emissions generated by solar wind exchange must be distinguished. With the help of simulations employing state-of-the-art magnetohydrodynamic models for the solar wind-magnetosphere interaction, models for Earth's exosphere, and knowledge concerning these background emissions, Sect. 5 demonstrates that boundaries and regions such as the bow shock, magnetosheath, magnetopause, and cusps can readily be identified in images of charge exchange emissions. Section 6 reviews observations by (generally narrow) field of view (FOV) astrophysical telescopes that confirm the presence of these emissions at the intensities predicted by the simulations. Section 7 describes the design of a notional wide FOV "lobster-eye" telescope capable of imaging the global interactions and shows how it might be used to extract information concerning the global interaction of the solar wind with solar system obstacles. The conclusion outlines prospects for missions employing such wide FOV imagers.

In-situ Plasma Analysis of Ion Kinetics in the Solar Wind and Hermean Magnetosphere

NASA Astrophysics Data System (ADS)

Tracy, Patrick J.

The heating of the solar wind and its interaction with the unique planetary magnetosphere of Mercury is the primary focus of this work. The first aspect of this study focused on the heavy ion population of the solar wind (A > 4 amu), and how well the signature of the heating process responsible for creating the solar wind is preserved in this heavy ion population. We found that this signature in the heavy ion population is primarily erased (thermalized) via Coulomb collisional interactions with solar wind protons. The heavy ions observed in collisionally young solar wind reveal a clear, stable dependence on mass, along with non-thermal heating that is not in agreement with current predictions based on turbulent transport and kinetic dissipation. Due to its weak magnetic dipole, the solar wind can impinge on the surface of Mercury, one of the processes contributing to the desorption of neutrals and, through ionization, ions that make up the planet's exosphere. Differentiating between surface mechanisms and analyzing magnetospheric plasma dynamics requires the quantification of a variety of ion species. A detailed forward model and a robust statistical method were created to identify new ion signatures in the measurement space of the FIPS instrument, formerly orbiting Mercury onboard the MESSENGER spacecraft. The recovery of new heavy ions species, including Al, Ne, Si, and Mg, along with tentative recoveries of S, Ar, K, and C, enable in depth studies of the plasma dynamics in the Hermean magnetosphere. The interaction of the solar wind with the bow shock of the Hermean magnetosphere leads to the creation of a foreshock region. New tools and methods were created to enable the analysis of the diffuse and Field Aligned Beam (FAB) populations in unique parameter regime of the Hermean foreshock. One result suggests that the energization process for the observed FABs can be explained by Shock Drift Acceleration, and not limited by the small spatial size of Mercury's bow shock. Analysis of diffuse populations shows that a connection time limited diffusive shock acceleration is likely responsible for the behavior of the observed energy distributions.

Variations of Strahl Properties with Fast and Slow Solar Wind

NASA Technical Reports Server (NTRS)

Figueroa-Vinas, Adolfo; Goldstein, Melvyn L.; Gurgiolo, Chris

2008-01-01

The interplanetary solar wind electron velocity distribution function generally shows three different populations. Two of the components, the core and halo, have been the most intensively analyzed and modeled populations using different theoretical models. The third component, the strahl, is usually seen at higher energies, is confined in pitch-angle, is highly field-aligned and skew. This population has been more difficult to identify and to model in the solar wind. In this work we make use of the high angular, energy and time resolution and three-dimensional data of the Cluster/PEACE electron spectrometer to identify and analyze this component in the ambient solar wind during high and slow speed solar wind. The moment density and fluid velocity have been computed by a semi-numerical integration method. The variations of solar wind density and drift velocity with the general build solar wind speed could provide some insight into the source, origin, and evolution of the strahl.

Investigation of Solar Wind Correlations and Solar Wind Modifications Near Earth by Multi-Spacecraft Observations: IMP 8, WIND and INTERBALL-1

NASA Technical Reports Server (NTRS)

Paularena, Karolen I.; Richardson, John D.; Zastenker, Georgy N.

2002-01-01

The foundation of this Project is use of the opportunity available during the ISTP (International Solar-Terrestrial Physics) era to compare solar wind measurements obtained simultaneously by three spacecraft - IMP 8, WIND and INTERBALL-1 at wide-separated points. Using these data allows us to study three important topics: (1) the size and dynamics of near-Earth mid-scale (with dimension about 1-10 million km) and small-scale (with dimension about 10-100 thousand km) solar wind structures; (2) the reliability of the common assumption that solar wind conditions at the upstream Lagrangian (L1) point accurately predict the conditions affecting Earth's magnetosphere; (3) modification of the solar wind plasma and magnetic field in the regions near the Earth magnetosphere, the foreshock and the magnetosheath. Our Project was dedicated to these problems. Our research has made substantial contributions to the field and has lead others to undertake similar work.

Kinetic Modeling of the Lunar Dust-Plasma Environment

NASA Astrophysics Data System (ADS)

Kallio, Esa; Alho, Markku; Alvarez, Francisco; Barabash, Stas; Dyadechkin, Sergey; Fernandes, Vera; Futaana, Yoshifumi; Harri, Ari-Matti; Haunia, Touko; Heilimo, Jyri; Holmström, Mats; Jarvinen, Riku; Lue, Charles; Makela, Jakke; Porjo, Niko; Schmidt, Walter; Shahab, Fatemi; Siili, Tero; Wurz, Peter

2014-05-01

Modeling of the lunar dust and plasma environment is a challenging task because a self-consistent model should include ions, electrons and dust particles and numerous other factors. However, most of the parameters are not well established or constrained by measurements in the lunar environment. More precisely, a comprehensive model should contain electrons originating from 1) the solar wind, 2) the lunar material (photoelectrons, secondary electrons) and 3) the lunar dust. Ions originate from the solar wind, the lunar material, the lunar exosphere and the dust. To model the role of the dust in the lunar plasma environment is a highly complex task since the properties of the dust particles in the exosphere are poorly known (e.g. mass, size, shape, conductivity) or not known (e.g. charge and photoelectron emission) and probably are time dependent. Models should also include the effects of interactions between the surface and solar wind and energetic particles, and micrometeorites. Largely different temporal and spatial scales are also a challenge for the numerical models. In addition, the modeling of a region on the Moon - for example on the South Pole - at a given time requires also knowledge of the solar illumination conditions at that time, mineralogical and electric properties of the local lunar surface, lunar magnetic anomalies, solar UV flux and the properties of the solar wind. Harmful effects of lunar dust to technical devices and to human health as well as modeling of the properties of the lunar plasma and dust environment have been topics of two ESA funded projects L-DEPP and DPEM. In the presentation we will summarize some basic results and characteristics of plasma and fields near and around the Moon as studied and discovered in these projects. Especially, we analyse three different space and time scales by kinetic models: [1] the "microscale" region near surface with an electrostatic PIC (ions and electrons are particles) model, [2] the "mesoscale" region including lunar magnetic anomalies and [3] the global scale Moon-solar wind interaction with hybrid (ions as particles in massless electron fluid) models.

Mapping 3D plasma structure in the solar wind with the L1 constellation: joint observations from Wind, ACE, DSCOVR, and SoHO

NASA Astrophysics Data System (ADS)

Stevens, M. L.; Kasper, J. C.; Case, A. W.; Korreck, K. E.; Szabo, A.; Biesecker, D. A.; Prchlik, J.

2017-12-01

At this moment in time, four observatories with similar instrumentation- Wind, ACE, DSCOVR, and SoHO- are stationed directly upstream of the Earth and making continuous observations. They are separated by drift-time baselines of seconds to minutes, timescales on which MHD instabilities in the solar wind are known to grow and evolve, and spatial baselines of tens to 200 earth radii, length scales relevant to the Earth's magnetosphere. By comparing measurements of matched solar wind structures from the four vantage points, the form of structures and associated dynamics on these scales is illuminated. Our targets include shocks and MHD discontinuities, stream fronts, locii of reconnection and exhaust flow boundary layers, plasmoids, and solitary structures born of nonlinear instability. We use the tetrahedral quality factors and other conventions adopted for Cluster to identify periods where the WADS constellation is suitably non-degenerate and arranged in such a way as to enable specific types of spatial, temporal, or spatiotemporal inferences. We present here an overview of the geometries accessible to the L1 constellation and timing-based and plasma-based observations of solar wind structures from 2016-17. We discuss the unique potential of the constellation approach for space physics and space weather forecasting at 1 AU.

Solar wind influence on Jupiter's magnetosphere and aurora

NASA Astrophysics Data System (ADS)

Vogt, Marissa; Gyalay, Szilard; Withers, Paul

2016-04-01

Jupiter's magnetosphere is often said to be rotationally driven, with strong centrifugal stresses due to large spatial scales and a rapid planetary rotation period. For example, the main auroral emission at Jupiter is not due to the magnetosphere-solar wind interaction but is driven by a system of corotation enforcement currents that arises to speed up outflowing Iogenic plasma. Additionally, processes like tail reconnection are also thought to be driven, at least in part, by processes internal to the magnetosphere. While the solar wind is generally expected to have only a small influence on Jupiter's magnetosphere and aurora, there is considerable observational evidence that the solar wind does affect the magnetopause standoff distance, auroral radio emissions, and the position and brightness of the UV auroral emissions. We will report on the results of a comprehensive, quantitative study of the influence of the solar wind on various magnetospheric data sets measured by the Galileo mission from 1996 to 2003. Using the Michigan Solar Wind Model (mSWiM) to predict the solar wind conditions upstream of Jupiter, we have identified intervals of high and low solar wind dynamic pressure. We can use this information to quantify how a magnetospheric compression affects the magnetospheric field configuration, which in turn will affect the ionospheric mapping of the main auroral emission. We also consider whether there is evidence that reconnection events occur preferentially during certain solar wind conditions or that the solar wind modulates the quasi-periodicity seen in the magnetic field dipolarizations and flow bursts.

Greening the Grid: Pathways to Integrate 175 Gigawatts of Renewable Energy into India's Electric Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cochran, Jaquelin

This fact sheet overviews the Greening the Grid India grid integration study. The use of renewable energy (RE) sources, primarily wind and solar generation, is poised to grow significantly within the Indian power system. The Government of India has established a target of 175 gigawatts (GW) of installed RE capacity by 2022, including 60 GW of wind and 100 GW of solar, up from 29 GW wind and 9 GW solar at the beginning of 2017. Thanks to advanced weather and power system modeling made for this project, the study team is able to explore operational impacts of meeting India'smore » RE targets and identify actions that may be favorable for integration.« less

A thermal storage capacity market for non dispatchable renewable energies

NASA Astrophysics Data System (ADS)

Bennouna, El Ghali; Mouaky, Ammar; Arrad, Mouad; Ghennioui, Abdellatif; Mimet, Abdelaziz

2017-06-01

Due to the increasingly high capacity of wind power and solar PV in Germany and some other European countries and the high share of variable renewable energy resources in comparison to fossil and nuclear capacity, a power reserve market structured by auction systems was created to facilitate the exchange of balance power capacities between systems and even grid operators. Morocco has a large potential for both wind and solar energy and is engaged in a program to deploy 2000MW of wind capacity by 2020 and 3000 MW of solar capacity by 2030. Although the competitiveness of wind energy is very strong, it appears clearly that the wind program could be even more ambitious than what it is, especially when compared to the large exploitable potential. On the other hand, heavy investments on concentrated solar power plants equipped with thermal energy storage have triggered a few years ago including the launching of the first part of the Nour Ouarzazate complex, the goal being to reach stable, dispatchable and affordable electricity especially during evening peak hours. This paper aims to demonstrate the potential of shared thermal storage capacity between dispatchable and non dispatchable renewable energies and particularly CSP and wind power. Thus highlighting the importance of a storage capacity market in parallel to the power reserve market and the and how it could enhance the development of both wind and CSP market penetration.

Exploration of Solar Wind Acceleration Region Using Interplanetary Scintillation of Water Vapor Maser Source and Quasars

NASA Technical Reports Server (NTRS)

Tokumaru, Munetoshi; Yamauchi, Yohei; Kondo, Tetsuro

2001-01-01

Single-station observations of interplanetary scintillation UPS) at three microwave frequencies 2, 8, and 22GHz, were carried out between 1989 and 1998 using a large (34-micro farad) radio telescope at the Kashima Space Research Center of the Communications Research Laboratory. The aim of these observations was to explore the near-sun solar wind, which is the key region for the study of the solar wind acceleration mechanism. Strong quasars, 3C279 and 3C273B, were used for the Kashima IPS observations at 2 and 8GHz, and a water-vapor maser source, IRC20431, was used for the IPS observations at 22GHz. Solar wind speeds derived from Kashima IPS data suggest that the solar wind acceleration takes place at radial distances between 10 and 30 solar radii (Rs) from the sun. The properties of the turbulence spectrum (e.g. anisotropy, spectral index, inner scale) inferred from the Kashima data were found to change systematically in the solar wind acceleration region. While the solar wind in the maximum phase appears to be dominated by the slow wind, fast and rarefied winds associated with the coronal holes were found to develop significantly at high latitudes as the solar activity declined. Nevertheless, the Kashima data suggests that the location of the acceleration region is stable throughout the solar cycle.

Exploration of Solar Wind Acceleration Region Using Interplanetary Scintillation of Water Vapor Maser Source and Quasars

NASA Technical Reports Server (NTRS)

Tokumaru, Munetoshi; Yamauchi, Yohei; Kondo, Tetsuro

2001-01-01

Single-station observations of interplanetary scintillation (IPS) at three microwave frequencies; 2 GHz, 8 GHz and 22 GHz have been carried out between 1989 and 1998 using a large (34 m farad) radio telescope at the Kashima Space Research Center of the Communications Research Laboratory. The aim of these observations is to explore the near-sun solar wind, which is the key region for the study of the solar wind acceleration mechanism. Strong quasars; 3C279 and 3C273B were used for Kashima IPS observations at 2 GHz and 8 GHz, and a water vapor maser source, IRC20431 was used for the IPS observations at 22 GHz. Solar wind velocities derived from Kashima IPS data suggest that the solar wind acceleration takes place at radial distances between 10 and 30 solar radii (R(sub s)) from the sun. Properties of the turbulence spectrum (e.g. anisotropy, spectral index, inner scale) inferred from Kashima data are found to change systematically in the solar wind acceleration region. While the solar wind in the maximum phase appears to be dominated by the slow wind, fast and rarefied winds associated with coronal holes are found to develop significantly at high latitudes as the solar activity declines. Nevertheless, Kashima data suggests that the location of the acceleration region is stable throughout the solar cycle.

The solar wind neon abundance observed with ACE/SWICS and ULYSSES/SWICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shearer, Paul; Raines, Jim M.; Lepri, Susan T.

Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on wind speed and evolution with the solar cycle. We find that Ne/O is inversely correlated with wind speed, is nearly constant in the fast wind, and correlates strongly with solar activity in the slow wind. In fast wind streams with speeds above 600 km s{sup –1}, we find Ne/O = 0.10 ± 0.02, in good agreement with the extensive polar observations by Ulysses/SWICS. In slow wind streams with speeds below 400 km s{sup –1}, Ne/O ranges from amore » low of 0.12 ± 0.02 at solar maximum to a high of 0.17 ± 0.03 at solar minimum. These measurements place new and significant empirical constraints on the fractionation mechanisms governing solar wind composition and have implications for the coronal and photospheric abundances of neon and oxygen. The results are made possible by a new data analysis method that robustly identifies rare elements in the measured ion spectra. The method is also applied to Ulysses/SWICS data, which confirms the ACE observations and extends our view of solar wind neon into the three-dimensional heliosphere.« less

Anomalously low C6+/C5+ ratio in solar wind: ACE/SWICS observation

NASA Astrophysics Data System (ADS)

Zhao, L.; Landi, E.; Kocher, M.; Lepri, S. T.; Fisk, L. A.; Zurbuchen, T. H.

2016-03-01

The Carbon and Oxygen ionization states in the solar wind plasma freeze-in within 2 solar radii (Rs) from the solar surface, and then they do not change as they propagate with the solar wind into the heliosphere. Therefore, the O7+/O6+ and C6+/C5+ charge state ratios measured in situ maintain a record of the thermal properties (electron temperature and density) of the inner corona where the solar wind originates. Since these two ratios freeze-in at very similar height, they are expected to be correlated. However, an investigation of the correlation between these two ratios as measured by ACE/SWICS instrument from 1998 to 201l shows that there is a subset of "Outliers" departing from the expected correlation. We find about 49.4% of these Outliers is related to the Interplanetary Coronal Mass Ejections (ICMEs), while 49.6% of them is slow speed wind (Vp < 500 km/s) and about 1.0% of them is fast solar wind (Vp > 500 km/s). We compare the outlier-slow-speed wind with the normal slow wind (defined as Vp < 500 km/s and O7+/O6+ > 0.2) and find that the reason that causes the Outliers to depart from the correlation is their extremely depleted C6+/C5+ ratio which is decreased by 80% compared to the normal slow wind. We discuss the implication of the Outlier solar wind for the solar wind acceleration mechanism.

Space-based measurements of elemental abundances and their relation to solar abundances

NASA Technical Reports Server (NTRS)

Coplan, M. A.; Ogilvie, K. W.; Bochsler, P.; Geiss, J.

1990-01-01

The Ion Composition Instrument (ICI) aboard the ISEE-3/ICE spacecraft was in the solar wind continuously from August 1978 to December 1982. The results made it possible to establish long-term average solar wind abundance values for helium, oxygen, neon, silicon, and iron. The Charge-Energy-Mass instrument aboard the CCE spacecraft of the AMPTE mission has measured the abundance of these elements in the magnetosheath and has also added carbon, nitrogen, magnesium, and sulfur to the list. There is strong evidence that these magnetosheath abundances are representative of the solar wind. Other sources of solar wind abundances are Solar Energetic Particle experiments and Apollo lunar foils. When comparing the abundances from all of these sources with photospheric abundances, it is clear that helium is depleted in the solar wind while silicon and iron are enhanced. Solar wind abundances for carbon, nitrogen, oxygen, and neon correlate well with the photospheric values. The incorporation of minor ions into the solar wind appears to depend upon both the ionization times for the elements and the Coulomb drag exerted by the outflowing proton flux.

The structure of the inner heliosphere from Pioneer Venus and IMP observations

NASA Technical Reports Server (NTRS)

Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.

1992-01-01

The IMP 8 and Pioneer Venus Orbiter (PVO) spacecraft explore the region of heliographic latitudes between 8 deg N and 8 deg S. Solar wind observations from these spacecraft are used to construct synoptic maps of solar wind parameters in this region. These maps provide an explicit picture of the structure of high speed streams near 1 AU and how that structure varies with time. From 1982 until early 1985, solar wind parameters varied little with latitude. During the last solar minimum, the solar wind developed strong latitudinal structure; high speed streams were excluded from the vicinity of the solar equator. Synoptic maps of solar wind speed are compared with maps of the coronal source surface magnetic field. This comparison reveals the expected correlation between solar wind speed near 1 AU, the strength of the coronal magnetic field, and distance from the coronal neutral line.

Elemental abundances in corotating events

NASA Technical Reports Server (NTRS)

Vonrosenvinge, T. T.; Mcguire, R. E.

1985-01-01

Large, persistent solar-wind streams in 1973 and 1974 produced corotating interaction regions which accelerated particles to energies of a few MeV/nucleon. The proton to helium ratio (H/He) was remarkably constant at a value (22 + or 5) equal to that in the solar wind (21 + or - 3), suggesting that particles were being accelerated directly out of the solar wind. Preliminary results were presented from a similar study approximately 11 years (i.e., one solar cycle) later. Corotating events have been identified by surveying the solar wind data, energetic particle time-histories and anisotropies. This data was all obtained from the ISEE-3/ICE spacecraft. These events also show H/He ratios similar to that in the solar wind. It is flund that in these cases there is evidence for H/He ratios which are significantly different from that of the solar wind but which are consistent with the range of values found in solar flare events.

Latitudinal variation of speed and mass flux in the acceleration region of the solar wind inferred from spectral broadening measurements

NASA Technical Reports Server (NTRS)

Woo, Richard; Goldstein, Richard M.

1994-01-01

Spectral broadening measurements conducted at S-band (13-cm wavelength) during solar minimum conditions in the heliocentric distance range of 3-8 R(sub O) by Mariner 4, Pioneer 10, Mariner 10, Helios 1, Helios 2, and Viking have been combined to reveal a factor of 2.6 reduction in bandwidth from equator to pole. Since spectral broadening bandwidth depends on electron density fluctuation and solar wind speed, and latitudinal variation of the former is available from coherence bandwidth measurements, the remote sensing spectral broadening measurements provide the first determination of the latitudinal variation of solar wind speed in the acceleration region. When combined with electron density measurements deduced from white-light coronagraphs, this result also leads to the first determination of the latitudinal variation of mass flux in the acceleration region. From equator to pole, solar wind speed increases by a factor of 2.2, while mass flux decreases by a factor of 2.3. These results are consistent with measurements of solar wind speed by multi-station intensity scintillation measurements, as well as measurements of mass flux inferred from Lyman alpha observations, both of which pertain to the solar wind beyond 0.5 AU. The spectral broadening observations, therefore, strengthen earlier conclusions about the latitudinal variation of solar wind speed and mass flux, and reinforce current solar coronal models and their implications for solar wind acceleration and solar wind modeling.

Solar Technologies

ERIC Educational Resources Information Center

von Hippel, Frank; Williams, Robert H.

1975-01-01

As fossil fuels decrease in availability and environmental concerns increase, soalr energy is becoming a potential major energy source. Already solar energy is used for space heating in homes. Proposals for solar-electric generating systems include land-based or ocean-based collectors and harnessing wind and wave power. Photosynthesis can also…

Modeling and Implementing a Digitally Embedded Maximum Power Point Tracking Algorithm and a Series-Loaded Resonant DC-DC Converter to Integrate a Photovoltaic Array with a Micro-Grid

DTIC Science & Technology

2014-09-01

These renewable energy sources can include solar, wind, geothermal , biomass, hydroelectric, and nuclear. Of these sources, photovoltaic (PV) arrays...renewable energy source [1]. These renewable energy sources can include solar, wind, geothermal , biomass, hydroelectric, and nuclear. Of these sources...26, May 2011. [6] H. G. Xu, J. P. He, Y. Qin, and Y. H. Li, “Energy management and control strategy for DC micro-grid in data center,” China

Deflection and Distortion of CME internal magnetic flux rope due to the interaction with a structured solar wind

NASA Astrophysics Data System (ADS)

Shiota, D.; Iju, T.; Hayashi, K.; Fujiki, K.; Tokumaru, M.; Kusano, K.

2016-12-01

CMEs are the most violent driver of geospace disturbances, and therefore their arrival to the Earth position is an important factor in space weather forecast. The dynamics of CME propagation is strongly affected by the interaction with background solar wind. To understand the interaction between a CME and background solar wind, we performed three-dimensional MHD simulations of the propagation of a CME with internal twisted magnetic flux rope into a structured bimodal solar wind. We compared three different cases in which an identical CME is launched into an identical bimodal solar wind but the launch dates of the CME are different. Each position relative to the boundary between slow and fast solar winds becomes almost in the slow wind stream region, almost in the fast wind stream region, or in vicinity of the boundary of the fast and slow solar wind stream (that grows to CIR). It is found that the CME is most distorted and deflected eastward in the case near the CIR, in contrast to the other two cases. The maximum strength of southward magnetic field at the Earth position is also highest in the case near CIR. The results are interpreted that the dynamic pressure gradient due to the back reaction from pushing the ahead slow wind stream and due to the collision behind fast wind stream hinders the expansion of the CME internal flux rope into the direction of the solar wind velocity gradient. As a result, the expansion into the direction to the velocity gradient is slightly enhanced and results in the enhanced deflection and distortion of the CME and its internal flux rope. These results support the pileup accident hypothesis proposed by Kataoka et al. (2015) to form unexpectedly geoeffective solar wind structure.

Mapping the Solar Wind from its Source Region into the Outer Corona

NASA Technical Reports Server (NTRS)

Esser, Ruth

1997-01-01

Knowledge of the radial variation of the plasma conditions in the coronal source region of the solar wind is essential to exploring coronal heating and solar wind acceleration mechanisms. The goal of the proposal was to determine as many plasma parameters in the solar wind acceleration region and beyond as possible by coordinating different observational techniques, such as Interplanetary Scintillation Observations, spectral line intensity observations, polarization brightness measurements and X-ray observations. The inferred plasma parameters were then used to constrain solar wind models.

Microphysics of Waves and Instabilities in the Solar Wind and their Macro Manifestations in the Corona and Interplanetary Space

NASA Technical Reports Server (NTRS)

Gurman, Joseph (Technical Monitor); Habbal, Shadia Rifai

2004-01-01

Investigations of the physical processes responsible for coronal heating and the acceleration of the solar wind were pursued with the use of our recently developed 2D MHD solar wind code and our 1D multifluid code. In particular, we explored (1) the role of proton temperature anisotropy in the expansion of the solar wind, (2) the role of plasma parameters at the coronal base in the formation of high speed solar wind streams at mid-latitudes, and (3) the heating of coronal loops.

Suprathermal electron loss cone distributions in the solar wind: Ulysses observations

NASA Technical Reports Server (NTRS)

Phillips, J. L.; Feldman, W. C.; Gosling, J. T.; Hammond, C. M.; Forsyth, R. J.

1995-01-01

Solar wind suprathermal electron distributions in the solar wind generally carry a field-aligned antisunward heat flux. Within coronal mass ejections and upstream of strong shocks driven by corotating interaction regions (CIRs), counterstreaming electron beams are observed. We present observations by the Ulysses solar wind plasma experiment of a new class of suprathermal electron signatures. At low solar latitudes and heliocentric distances beyond 3.5 AU Ulysses encountered several intervals, ranging in duration from 1 hour to 22 hours, in which the suprathermal distributions included an antisunward field-aligned beam and a return population with a flux dropout typically spanning +/- 60 deg from the sunward field-aligned direction. All events occurred within CIRs, downstream of the forward and reverse shocks or waves bounding the interaction regions. We evaluate the hypothesis that the sunward-moving electrons result from reflection of the antisunward beams at magnetic field compressions downstream from the observations, with wide loss cones caused by the relatively weak compression ratio. This hypothesis requires that field magnitude within the CIRs actually increase with increasing field-aligned distance from the Sun. Details of the electron distributions and ramifications for CIR and shock geometry will be presented.

The Poynting-Robertson effect: A critical perspective

NASA Astrophysics Data System (ADS)

Klačka, J.; Petržala, J.; Pástor, P.; Kómar, L.

2014-04-01

Physics of the Poynting-Robertson (P-R) effect is discussed and compared with the statements published in the past 30 years. Relativistically covariant formulation reveals the essence of the P-R effect and points out to nonphysical explanations in scientific papers and monographs. Although the final equation of motion m dv→/dt=(SA‧Q‾pr‧/c)[(1-v→·e→/c)e→-v→/c] has been usually correctly presented and used, its derivation and explanation of its essence is frequently incorrect. The difference between the effects of solar electromagnetic and corpuscular (solar wind) radiation is stressed. The force acting on the particle due to the solar wind (the simple case of radial solar wind velocity is considered) is F→sw=Fsw[(1-v→·e→/vsw)e→-x‧v→/vsw], where Fsw is the force on the stationary particle, vsw is the heliocentric solar-wind speed, and, the value of x‧ depends on material properties of the particle (1 < x‧ < 3). We present secular orbital evolution of dust particle under the action of the P-R effect. Initial conditions are included. Time of spiralling of the particle into the Sun is analytically calculated. Secular evolutions of perihelion and aphelion distances are investigated.

Report of the solar physics panel

NASA Technical Reports Server (NTRS)

Withbroe, George L.; Fisher, Richard R.; Antiochos, Spiro; Brueckner, Guenter; Hoeksema, J. Todd; Hudson, Hugh; Moore, Ronald; Radick, Richard R.; Rottman, Gary; Scherrer, Philip

1991-01-01

Recent accomplishments in solar physics can be grouped by the three regions of the Sun: the solar interior, the surface, and the exterior. The future scientific problems and areas of interest involve: generation of magnetic activity cycle, energy storage and release, solar activity, solar wind and solar interaction. Finally, the report discusses a number of future space mission concepts including: High Energy Solar Physics Mission, Global Solar Mission, Space Exploration Initiative, Solar Probe Mission, Solar Variability Explorer, Janus, as well as solar physics on Space Station Freedom.

A study of the solar wind angular momentum including proton thermal anisotropy. Ph.D. Thesis - Catholic Univ. of Am., 1973

NASA Technical Reports Server (NTRS)

Acuna, M. H.

1974-01-01

The solution to the steady state magnetohydrodynamic equations governing the supersonic expansion of the solar corona into interplanetary space is obtained for various assumptions regarding the form in which proton thermal energy is carried away from the sun. The one-fluid, inviscid, formulation of the MHD equations is considered assuming that thermal energy is carried away by conduction from a heat source located at the base of the corona. Angular motion of the solar wind led to the existence of three critical points through which the numerical solutions must pass to extend from the sun's surface to large heliocentric distances. The results show that the amount of magnetic field energy converted into kinetic energy in the solar wind is only a small fraction of the total expansion energy flux and has little effect upon the final radial expansion velocity.

Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation

NASA Technical Reports Server (NTRS)

Cliver, E. W.; Richardson, I. G.; Ling, A. G.

2011-01-01

In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift: at such times. In 2009, the approx.2 GV GCR intensity measured by the Newark neutron monitor increased by approx.5% relative to its maximum value two cycles earlier even though the average tilt angle in 2009 was slightly larger than that in 1986 (approx.20deg vs. approx.14deg), while solar wind B was significantly lower (approx.3.9 nT vs. approx.5.4 nT). A decomposition of the solar wind into high-speed streams, slow solar wind, and coronal mass ejections (CMEs; including postshock flows) reveals that the Sun transmits its message of changing magnetic field (diffusion coefficient) to the heliosphere primarily through CMEs at solar maximum and high-speed streams at solar minimum. Long-term reconstructions of solar wind B are in general agreement for the approx. 1900-present interval and can be used to reliably estimate GCR intensity over this period. For earlier epochs, however, a recent Be-10-based reconstruction covering the past approx. 10(exp 4) years shows nine abrupt and relatively short-lived drops of B to < or approx.= 0 nT, with the first of these corresponding to the Sporer minimum. Such dips are at variance with the recent suggestion that B has a minimum or floor value of approx.2.8 nT. A floor in solar wind B implies a ceiling in the GCR intensity (a permanent modulation of the local interstellar spectrum) at a given energy/rigidity. The 30-40% increase in the intensity of 2.5 GV electrons observed by Ulysses during the recent solar minimum raises an interesting paradox that will need to be resolved.

Three-dimensional exploration of the solar wind using observations of interplanetary scintillation

PubMed Central

TOKUMARU, Munetoshi

2013-01-01

The solar wind, a supersonic plasma flow continuously emanating from the Sun, governs the space environment in a vast region extending to the boundary of the heliosphere (∼100 AU). Precise understanding of the solar wind is of importance not only because it will satisfy scientific interest in an enigmatic astrophysical phenomenon, but because it has broad impacts on relevant fields. Interplanetary scintillation (IPS) of compact radio sources at meter to centimeter wavelengths serves as a useful ground-based method for investigating the solar wind. IPS measurements of the solar wind at a frequency of 327 MHz have been carried out regularly since the 1980s using the multi-station system of the Solar-Terrestrial Environment Laboratory (STEL) of Nagoya University. This paper reviews new aspects of the solar wind revealed from our IPS observations. PMID:23391604

LOCKYER (Large Optimized Coronagraph for KeY Emission line Research): A SMEX Mission to Provide Crucial Measurements of the Genesis of the Solar Wind and CMEs

NASA Astrophysics Data System (ADS)

Ko, Y. K.; Vourlidas, A.; Korendyke, C.; Laming, J. M.

2016-12-01

The LOCKYER mission is designed to uncover the physical processes of acceleration and heating of the quiescent and transient solar wind. It builds on the success of the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO with a massive increase in effective area at Lyman-alpha (200x larger than UVCS), thanks to a modern optical design and the use of a 4m boom. The larger effective area enables spectral line observations from many ions, including He II (at 1640 Å), allowing us to access the region where the coronal plasma transitions from fluid to kinetic behavior. In addition, a visible light channel provides simultaneous high-resolution coronagraphic images for the global coronal structure and dynamics creating a greatly-expanded UVCS-LASCO `hybrid' instrument within the tight constraints of a SMEX mission. The LOCKYER mission aims to answer the following questions: 1) What are the physical processes responsible for the heating and acceleration of the primary (proton, electron, helium) and secondary (minor ion) plasma components of the fast and slow solar wind? 2) How are CMEs heated and accelerated? LOCKYER would greatly advance our knowledge of how and where the solar wind is formed, and how the variations in coronal microphysics impact the solar wind and heliosphere. The LOCKYER measurements are highly complementary to the Solar Probe Plus and Solar Orbiter measurements and provide detailed empirical descriptions of the coronal plasma at heights where the primary energy and momentum addition occur.

Little or no solar wind enters Venus' atmosphere at solar minimum.

PubMed

Zhang, T L; Delva, M; Baumjohann, W; Auster, H-U; Carr, C; Russell, C T; Barabash, S; Balikhin, M; Kudela, K; Berghofer, G; Biernat, H K; Lammer, H; Lichtenegger, H; Magnes, W; Nakamura, R; Schwingenschuh, K; Volwerk, M; Vörös, Z; Zambelli, W; Fornacon, K-H; Glassmeier, K-H; Richter, I; Balogh, A; Schwarzl, H; Pope, S A; Shi, J K; Wang, C; Motschmann, U; Lebreton, J-P

2007-11-29

Venus has no significant internal magnetic field, which allows the solar wind to interact directly with its atmosphere. A field is induced in this interaction, which partially shields the atmosphere, but we have no knowledge of how effective that shield is at solar minimum. (Our current knowledge of the solar wind interaction with Venus is derived from measurements at solar maximum.) The bow shock is close to the planet, meaning that it is possible that some solar wind could be absorbed by the atmosphere and contribute to the evolution of the atmosphere. Here we report magnetic field measurements from the Venus Express spacecraft in the plasma environment surrounding Venus. The bow shock under low solar activity conditions seems to be in the position that would be expected from a complete deflection by a magnetized ionosphere. Therefore little solar wind enters the Venus ionosphere even at solar minimum.

Forecast of solar wind parameters according to STOP magnetograph observations

NASA Astrophysics Data System (ADS)

Tlatov, A. G.; Pashchenko, M. P.; Ponyavin, D. I.; Svidskii, P. M.; Peshcherov, V. S.; Demidov, M. L.

2016-12-01

The paper discusses the results of the forecast of solar wind parameters at a distance of 1 AU made according to observations made by the STOP telescope magnetograph during 2014-2015. The Wang-Sheeley-Arge (WSA) empirical model is used to reconstruct the magnetic field topology in the solar corona and estimate the solar wind speed in the interplanetary medium. The proposed model is adapted to STOP magnetograph observations. The results of the calculation of solar wind parameters are compared with ACE satellite measurements. It is shown that the use of STOP observations provides a significant correlation of predicted solar wind speed values with the observed ones.

SWCX Emission from the Helium Focusing Cone - Preliminary Results

NASA Technical Reports Server (NTRS)

Snowden, S. L.; Kuntz, K. D.; Collier, M. R.

2008-01-01

Preliminary results from an XMM-Newton campaign to study solar wind charge exchange (SWCX) emission from the heliospheric focusing cone of interstellar helium are presented. The detections of enhanced O VII and O VIII emission from the cone are at the 2(sigma) and 4(sigma) levels. The solar wind charge exchange (SWCX) emission in the heliosphere not associated with distinct objects (e.g., comets and planets including exospheric material in and near Earth s magnetosheath) is proportional to the flux of the solar wind and the space density of neutral material. The neutral material originates in the interstellar medium (ISM) and passes through the solar system due to the relative motion of the Sun and the ISM. The flow of the neutral material through the solar system is strongly perturbed by the Sun both by gravity and by radiation pressure. Because of the relative radiative scattering cross sections and the effect of solar gravitation the density of interstellar hydrogen near the Sun is reduced while interstellar helium is gravitationally focused. This creates a helium focusing cone downstream of the Sun [e.g., 1, and references therein].

A multi-timescale view on the slow solar wind with MTOF

NASA Astrophysics Data System (ADS)

Heidrich-Meisner, Verena; Wimmer-Schweingruber, Robert F.; Wurz, Peter; Bochsler, Peter; Ipavich, Fred M.; Paquette, John A.; Klecker, Bernard

2013-04-01

The solar wind is known to be composed of several different types of wind. Their respective differences in speed gives rise to the somewhat crude categories slow and fast wind. However, slow and fast winds also differ in their composition and plasma properties. While coronal holes are accepted as the origin of the fast wind (e.g. [Tu2005]), slow wind is hypothesized to emanate from different regions and to be caused by different mechanisms, although the average properties of slow wind are remarkably uniform. Models for the origin of the slow solar wind fall in three categories. In the first category, slow wind originates from the edges of coronal holes and is driven by reconnection of open field lines from the coronal hole with closed loops [Schwadron2005]. The second category relies on reconnection as well but places the source regions of the slow solar wind at the boundaries of active regions [Sakao2007]. A topological argument underlies the third group which requires that all coronal holes are connected by the so-called "S-web" as the driver of the slow solar wind [Antiochos2011]. Solar wind composition has been continuously measured by for example SOHO/CELIAS and ACE/SWICS. In this work we focus on the mass time-of-flight instrument of SOHO/CELIAS/MTOF [Hovestadt1995], which has been collecting data from 1996 to the present day. Whereas much attention in previous years has been focused on spectacular features of the solar wind like (interplanetary) coronal mass ejections (ICMEs) our main interest lies in understanding the slow solar wind. Although it is remarkably homogeneous in its average properties (e.g. [vonSteiger2000]) it contains many short term variations. This motivates us to investigate the slow solar wind on multiple timescales with a special focus on identifying individual stream with unusual compositions. A first step in this is to identify individual streams. A useful tool to do this reliably is specific entropy [Pagel2004]. Consequently, this leads to an extensive picture of individual streams from MTOF, which can be combined with observations from other spacecraft in the future. In particular, identifying and understanding short-term variations of the slow solar wind has the potential to help distinguishing between different possible source regions and mechanisms. Further, with the long term goal of identifying possible different source mechanisms or regions, we analyze and compare the properties of individual streams on short time scales to focus on significant deviations from the average properties of slow solar wind. References [Antiochos2011] SK Antiochos, Z. Mikic, VS Titov, R. Lionello, and JA Linker. A model for the sources of the slow solar wind. The Astrophysical Journal, 731(2):112, 2011. [Hovestadt1995] D. Hovestadt, M. Hilchenbach, A. Bürgi, B. Klecker, P. Laeverenz, M. Scholer, H. Grünwaldt, WI Axford, S. Livi, E. Marsch, et al. Celias-charge, element and isotope analysis system for soho. Solar Physics, 162(1):441-481, 1995. [Pagel2004] AC Pagel, NU Crooker, TH Zurbuchen, and JT Gosling. Correlation of solar wind entropy and oxygen ion charge state ratio. Journal of geophysical research, 109(A1):A01113, 2004. [Sakao2007] T. Sakao, R. Kano, N. Narukage, J. Kotoku, T. Bando, E.E. DeLuca, L.L. Lundquist, S. Tsuneta, L.K. Harra, Y. Katsukawa, et al. Continuous plasma outflows from the edge of a solar active region as a possible source of solar wind. Science, 318(5856):1585-1588, 2007. [Schwadron2005] NA Schwadron, DJ McComas, HA Elliott, G. Gloeckler, J. Geiss, and R. Von Steiger. Solar wind from the coronal hole boundaries. Journal of geophysical research, 110(A4):A04104, 2005. [Tu2005] C.Y. Tu, C. Zhou, E. Marsch, L.D. Xia, L. Zhao, J.X. Wang, and K. Wilhelm. Solar wind origin in coronal funnels. Science, 308(5721):519-523, 2005. [vonSteiger2000] R. Von Steiger, N. Schwadron, LA Fisk, J. Geiss, G. Gloeckler, S. Hefti, B. Wilken, RF Wimmer-Schweingruber, and TH Zurbuchen. Composition of quasi-stationary solar wind flows from ulysses/solar wind ion composition spectrometer. Journal of geophysical research, 105:27, 2000.

Imaging the Top of the Solar Corona and the Young Solar Wind

NASA Astrophysics Data System (ADS)

DeForest, C. E.; Matthaeus, W. H.; Viall, N. M.; Cranmer, S. R.

2016-12-01

We present the first direct visual evidence of the quasi-stationary breakup of solar coronal structure and the rise of turbulence in the young solar wind, directly in the future flight path of Solar Probe. Although the corona and, more recently, the solar wind have both been observed directly with Thomson scattered light, the transition from the corona to the solar wind has remained a mystery. The corona itself is highly structured by the magnetic field and the outflowing solar wind, giving rise to radial "striae" - which comprise the familiar streamers, pseudostreamers, and rays. These striae are not visible in wide-field heliospheric images, nor are they clearly delineated with in-situ measurements of the solar wind. Using careful photometric analysis of the images from STEREO/HI-1, we have, for the first time, directly observed the breakup of radial coronal structure and the rise of nearly-isotropic turbulent structure in the outflowing slow solar wind plasma between 10° (40 Rs) and 20° (80 Rs) from the Sun. These observations are important not only for their direct science value, but for predicting and understanding the conditions expected near SPP as it flies through - and beyond - this final frontier of the heliosphere, the outer limits of the solar corona.

A survey of solar wind conditions at 5 AU: A tool for interpreting solar wind-magnetosphere interactions at Jupiter

NASA Astrophysics Data System (ADS)

Ebert, Robert; Bagenal, Fran; McComas, David; Fowler, Christopher

2014-09-01

We examine Ulysses solar wind and interplanetary magnetic field (IMF) observations at 5 AU for two ~13 month intervals during the rising and declining phases of solar cycle 23 and the predicted response of the Jovian magnetosphere during these times. The declining phase solar wind, composed primarily of corotating interaction regions and high-speed streams, was, on average, faster, hotter, less dense, and more Alfvénic relative to the rising phase solar wind, composed mainly of slow wind and interplanetary coronal mass ejections. Interestingly, none of solar wind and IMF distributions reported here were bimodal, a feature used to explain the bimodal distribution of bow shock and magnetopause standoff distances observed at Jupiter. Instead, many of these distributions had extended, non-Gaussian tails that resulted in large standard deviations and much larger mean over median values. The distribution of predicted Jupiter bow shock and magnetopause standoff distances during these intervals were also not bimodal, the mean/median values being larger during the declining phase by ~1 - 4%. These results provide data-derived solar wind and IMF boundary conditions at 5 AU for models aimed at studying solar wind-magnetosphere interactions at Jupiter and can support the science investigations of upcoming Jupiter system missions. Here, we provide expectations for Juno, which is scheduled to arrive at Jupiter in July 2016. Accounting for the long-term decline in solar wind dynamic pressure reported by McComas et al. (2013), Jupiter’s bow shock and magnetopause is expected to be at least 8 - 12% further from Jupiter, if these trends continue.

Were chondrites magnetized by the early solar wind?

NASA Astrophysics Data System (ADS)

Oran, Rona; Weiss, Benjamin P.; Cohen, Ofer

2018-06-01

Chondritic meteorites have been traditionally thought to be samples of undifferentiated bodies that never experienced large-scale melting. This view has been challenged by the existence of post-accretional, unidirectional natural remanent magnetization (NRM) in CV carbonaceous chondrites. The relatively young inferred NRM age [∼10 million years (My) after solar system formation] and long duration of NRM acquisition (1-106 y) have been interpreted as evidence that the magnetizing field was that of a core dynamo within the CV parent body. This would imply that CV chondrites represent the primitive crust of a partially differentiated body. However, an alternative hypothesis is that the NRM was imparted by the early solar wind. Here we demonstrate that the solar wind scenario is unlikely due to three main factors: 1) the magnitude of the early solar wind magnetic field is estimated to be <0.1 μT in the terrestrial planet-forming region, 2) the resistivity of chondritic bodies limits field amplification due to pile-up of the solar wind to less than a factor of 3.5 times that of the instantaneous solar wind field, and 3) the solar wind field likely changed over timescales orders of magnitude shorter than the timescale of NRM acquisition. Using analytical arguments, numerical simulations and astronomical observations of the present-day solar wind and magnetic fields of young stars, we show that the maximum mean field the ancient solar wind could have imparted on an undifferentiated CV parent body is <3.5 nT, which is 3-4 and 3 orders of magnitude weaker than the paleointensities recorded by the CV chondrites Allende and Kaba, respectively. Therefore, the solar wind is highly unlikely to be the source of the NRM in CV chondrites. Nevertheless, future high sensitivity paleomagnetic studies of rapidly-cooled meteorites with high magnetic recording fidelity could potentially trace the evolution of the solar wind field in time.

TURBULENCE IN THE SOLAR WIND MEASURED WITH COMET TAIL TEST PARTICLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeForest, C. E.; Howard, T. A.; Matthaeus, W. H.

2015-10-20

By analyzing the motions of test particles observed remotely in the tail of Comet Encke, we demonstrate that the solar wind undergoes turbulent processing enroute from the Sun to the Earth and that the kinetic energy entrained in the large-scale turbulence is sufficient to explain the well-known anomalous heating of the solar wind. Using the heliospheric imaging (HI-1) camera on board NASA's STEREO-A spacecraft, we have observed an ensemble of compact features in the comet tail as they became entrained in the solar wind near 0.4 AU. We find that the features are useful as test particles, via mean-motion analysismore » and a forward model of pickup dynamics. Using population analysis of the ensemble's relative motion, we find a regime of random-walk diffusion in the solar wind, followed, on larger scales, by a surprising regime of semiconfinement that we attribute to turbulent eddies in the solar wind. The entrained kinetic energy of the turbulent motions represents a sufficient energy reservoir to heat the solar wind to observed temperatures at 1 AU. We determine the Lagrangian-frame diffusion coefficient in the diffusive regime, derive upper limits for the small scale coherence length of solar wind turbulence, compare our results to existing Eulerian-frame measurements, and compare the turbulent velocity with the size of the observed eddies extrapolated to 1 AU. We conclude that the slow solar wind is fully mixed by turbulence on scales corresponding to a 1–2 hr crossing time at Earth; and that solar wind variability on timescales shorter than 1–2 hr is therefore dominated by turbulent processing rather than by direct solar effects.« less

ULF Wave Activity in the Magnetosphere: Resolving Solar Wind Interdependencies to Identify Driving Mechanisms

NASA Astrophysics Data System (ADS)

Bentley, S. N.; Watt, C. E. J.; Owens, M. J.; Rae, I. J.

2018-04-01

Ultralow frequency (ULF) waves in the magnetosphere are involved in the energization and transport of radiation belt particles and are strongly driven by the external solar wind. However, the interdependency of solar wind parameters and the variety of solar wind-magnetosphere coupling processes make it difficult to distinguish the effect of individual processes and to predict magnetospheric wave power using solar wind properties. We examine 15 years of dayside ground-based measurements at a single representative frequency (2.5 mHz) and a single magnetic latitude (corresponding to L ˜ 6.6RE). We determine the relative contribution to ULF wave power from instantaneous nonderived solar wind parameters, accounting for their interdependencies. The most influential parameters for ground-based ULF wave power are solar wind speed vsw, southward interplanetary magnetic field component Bz<0, and summed power in number density perturbations δNp. Together, the subordinate parameters Bz and δNp still account for significant amounts of power. We suggest that these three parameters correspond to driving by the Kelvin-Helmholtz instability, formation, and/or propagation of flux transfer events and density perturbations from solar wind structures sweeping past the Earth. We anticipate that this new parameter reduction will aid comparisons of ULF generation mechanisms between magnetospheric sectors and will enable more sophisticated empirical models predicting magnetospheric ULF power using external solar wind driving parameters.

Global Network of Slow Solar Wind

NASA Technical Reports Server (NTRS)

Crooker, N. U.; Antiochos, S. K.; Zhao, X.; Neugebauer, M.

2012-01-01

The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These areas commonly have the form of an arc that is connected to the streamer belt at both ends. The arcs mark the boundaries between fields emanating from different coronal holes of the same polarity and thus trace the paths of belts of pseudostreamers, i.e., unipolar streamers that form over double arcades and lack current sheets. The arc pattern is consistent with the predicted topological mapping of the narrow open corridor or singular separator line that must connect the holes and, thus, consistent with the separatrix-web model of the slow solar wind. Near solar maximum, pseudostreamer belts stray far from the HCS-associated streamer belt and, together with it, form a global-wide web of slow wind. Recognition of pseudostreamer belts as prominent sources of slow wind provides a new template for understanding solar wind stream structure, especially near solar maximum.

Hawaii Solar and Wind Integration Studies | Grid Modernization | NREL

Science.gov Websites

Solar Integration Study and Oahu Wind Integration and Transmission Study investigated the effects of high penetrations of renewables on island grids. Hawaii Solar Integration Study The Hawaii Solar Integration Study was a detailed technical examination of the effects of high penetrations of solar and wind

The average solar wind in the inner heliosphere: Structures and slow variations

NASA Technical Reports Server (NTRS)

Schwenn, R.

1983-01-01

Measurements from the HELIOS solar probes indicated that apart from solar activity related disturbances there exist two states of the solar wind which might result from basic differences in the acceleration process: the fast solar wind (v 600 kms(-)1) emanating from magnetically open regions in the solar corona and the "slow" solar wind (v 400 kms(-)1) correlated with the more active regions and its mainly closed magnetic structures. In a comprehensive study using all HELIOS data taken between 1974 and 1982 the average behavior of the basic plasma parameters were analyzed as functions of the solar wind speed. The long term variations of the solar wind parameters along the solar cycle were also determined and numerical estimates given. These modulations appear to be distinct though only minor. In agreement with earlier studies it was concluded that the major modulations are in the number and size of high speed streams and in the number of interplanetary shock waves caused by coronal transients. The latter ones usually cause huge deviations from the averages of all parameters.

The magnetospheric electric field and convective processes as diagnostics of the IMF and solar wind

NASA Technical Reports Server (NTRS)

Kaye, S. M.

1979-01-01

Indirect measurements of the convection field as well as direct of the ionospheric electric field provide a means to at least monitor quanitatively solar wind processes. For instance, asymmetries in the ionospheric electric field and ionospheric Hall currents over the polar cap reflect the solar wind sector polarity. A stronger electric field, and thus convective flow, is found on the side of the polar cap where the y component of the IMF is parallel to the y component of the geomagnetic field. Additionally, the magnitude of the electric field and convective southward B sub Z and/or solar wind velocity, and thus may indicate the arrival at Earth of an interaction region in the solar wind. It is apparent that processes associated with the convention electric field may be used to predict large scale features in the solar wind; however, with present empirical knowledge it is not possible to make quantitative predictions of individual solar wind or IMF parameters.

An electrodynamic model of electric currents and magnetic fields in the dayside ionosphere of Venus

NASA Technical Reports Server (NTRS)

Cloutier, P. A.; Tascione, T. F.; Danieli, R. E., Jr.

1981-01-01

The electric current configuration induced in the ionosphere of Venus by the interaction of the solar wind has been calculated in previous papers (Cloutier and Daniell, 1973; Daniell and Cloutier, 1977; Cloutier and Daniell, 1979) for average steady-state solar wind conditions and interplanetary magnetic field. This model is generalized to include the effects of (1) plasma depletion and magnetic field enhancement near the ionopause, (2) velocity-shear-induced MHD instabilities of the Kelvin-Helmholtz type within the ionosphere, and (3) variations in solar wind parameters and interplanetary magnetic field. It is shown that the magnetic field configuration resulting from the model varies in response to changes in solar wind and interplanetary field conditions, and that these variations produce magnetic field profiles in excellent agreement with those seen by the Pioneer-Venus Orbiter. The formation of flux-ropes by the Kelving-Helmholtz instability is shown to be a natural consequence of the model, with the spatial distribution and size of the flux-ropes determined by the magnetic Reynolds number.

Substorm occurrence rates, substorm recurrence times, and solar wind structure

NASA Astrophysics Data System (ADS)

Borovsky, Joseph E.; Yakymenko, Kateryna

2017-03-01

Two collections of substorms are created: 28,464 substorms identified with jumps in the SuperMAG AL index in the years 1979-2015 and 16,025 substorms identified with electron injections into geosynchronous orbit in the years 1989-2007. Substorm occurrence rates and substorm recurrence-time distributions are examined as functions of the phase of the solar cycle, the season of the year, the Russell-McPherron favorability, the type of solar wind plasma at Earth, the geomagnetic-activity level, and as functions of various solar and solar wind properties. Three populations of substorm occurrences are seen: (1) quasiperiodically occurring substorms with recurrence times (waiting times) of 2-4 h, (2) randomly occurring substorms with recurrence times of about 6-15 h, and (3) long intervals wherein no substorms occur. A working model is suggested wherein (1) the period of periodic substorms is set by the magnetosphere with variations in the actual recurrence times caused by the need for a solar wind driving interval to occur, (2) the mesoscale structure of the solar wind magnetic field triggers the occurrence of the random substorms, and (3) the large-scale structure of the solar wind plasma is responsible for the long intervals wherein no substorms occur. Statistically, the recurrence period of periodically occurring substorms is slightly shorter when the ram pressure of the solar wind is high, when the magnetic field strength of the solar wind is strong, when the Mach number of the solar wind is low, and when the polar-cap potential saturation parameter is high.

Termination of the solar wind in the hot, partially ionized interstellar medium. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lombard, C. K.

1974-01-01

Theoretical foundations for understanding the problem of the termination of the solar wind are reexamined in the light of most recent findings concerning the states of the solar wind and the local interstellar medium. The investigation suggests that a simple extention of Parker's (1961) analytical model provides a useful approximate description of the combined solar wind, interstellar wind plasma flowfield under conditions presently thought to occur. A linear perturbation solution exhibiting both the effects of photoionization and charge exchange is obtained for the supersonic solar wind. A numerical algorithm is described for computing moments of the non-equilibrium hydrogen distribution function and associated source terms for the MHD equations. Computed using the algorithm in conjunction with the extended Parker solution to approximate the plasma flowfield, profiles of hydrogen number density are given in the solar wind along the upstream and downstream axes of flow with respect to the direction of the interstellar wind. Predictions of solar Lyman-alpha backscatter intensities to be observed at 1 a.u. have been computed, in turn, from a set of such hydrogen number density profiles varied over assumed conditions of the interstellar wind.

The coherent relation between the solar wind proton speed and O{sup 7+}/O{sup 6+} ratio and its coronal sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, L., E-mail: lzh@umich.edu; Landi, E.; Fisk, L. A.

We analyze the two-hour resolution solar wind proton speed (V{sub p}) and charge state ratio of O{sup 7+}/O{sup 6+} measured by ACE (SWICS and SWEPAM) from 1998 to 2011 at 1 AU. By applying a two-step mapping method, we link the solar wind in-situ observations to the corona images captured by SOHO and STEREO, in which we identify the different plasma structures, such as active regions (ARs), coronal holes (CHs) and quiet Sun regions (QS), using a classification scheme based on pixel brightness. Then we determine from which region in the corona the solar wind originates. We examine the in-situmore » properties of the solar wind streams associated with CHs, ARs and QS regions. We find that more than half of CH associated wind is actually slow wind, and O{sup 7+}/O{sup 6+} ratio has a strong coherent correlation with the location of the solar wind coronal sources. Therefore, we conclude that O{sup 7+}/O{sup 6+} ratio can be used as a much more effective discriminator to identify solar wind coronal sources region than V{sub p}.« less

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.

Kinetic instabilities in the solar wind driven by temperature anisotropies

NASA Astrophysics Data System (ADS)

Yoon, Peter H.

2017-12-01

The present paper comprises a review of kinetic instabilities that may be operative in the solar wind, and how they influence the dynamics thereof. The review is limited to collective plasma instabilities driven by the temperature anisotropies. To limit the scope even further, the discussion is restricted to the temperature anisotropy-driven instabilities within the model of bi-Maxwellian plasma velocity distribution function. The effects of multiple particle species or the influence of field-aligned drift will not be included. The field-aligned drift or beam is particularly prominent for the solar wind electrons, and thus ignoring its effect leaves out a vast portion of important physics. Nevertheless, for the sake of limiting the scope, this effect will not be discussed. The exposition is within the context of linear and quasilinear Vlasov kinetic theories. The discussion does not cover either computer simulations or data analyses of observations, in any systematic manner, although references will be made to published works pertaining to these methods. The scientific rationale for the present analysis is that the anisotropic temperatures associated with charged particles are pervasively detected in the solar wind, and it is one of the key contemporary scientific research topics to correctly characterize how such anisotropies are generated, maintained, and regulated in the solar wind. The present article aims to provide an up-to-date theoretical development on this research topic, largely based on the author's own work.

Space Environmental Erosion of Polar Icy Regolith

NASA Technical Reports Server (NTRS)

Farrell, William M.; Killen, R. M.; Vondrak, R. R.; Hurley, D. M.; Stubbs, T. J.; Delory, G. T.; Halekas, J. S.; Zimmerman, M. I.

2011-01-01

While regions at the floors of permanently shadowed polar craters are isolated from direct sunlight, these regions are still exposed to the harsh space environment, including the interplanetary Lyman-a background, meteoric impacts, and obstacle-affected solar wind. We demonstrate that each of these processes can act to erode the polar icy regolith located at or near the surface along the crater floor. The Lyman-a background can remove/erode the icy-regolith via photon stimulated desorption [1], meteoric impacts can vaporize the regolith [2], and redirected solar wind ions can sputter the ice-regolith mix [3]. As an example we shall examine in detail the inflow of solar wind ions and electrons into polar craters, One might expect such ions to flow horizontally over the crater top (see Figure). However, we find that plasma ambipolar processes act to deflect passing ions into the craters [3]. We examine this plasma process and determine the ion flux as a function of position across a notional crater floor. We demonstrate that inflowing solar wind ions can indeed create sputtering along the crater floor, effectively eroding the surface. Erosion time scales rrom sputtering will be presented. We shall also consider the effect of impact vaporization on buried icy-regolith regions. There will also be a discussion of solar wind electrons that enter into the PSR, demonstrating that these also have the ability rree surface-bound atoms via electron stimulated desorption processes [l].

Energetics of the terrestrial bow shock

NASA Astrophysics Data System (ADS)

Hamrin, Maria; Gunell, Herbert; Norqvist, Patrik

2017-04-01

The solar wind is the primary energy source for the magnetospheric energy budget. Energy can enter through the magnetopause both as kinetic energy (plasma entering via e.g. magnetic reconnection and impulsive penetration) and as electromagnetic energy (e.g. by the conversion of solar wind kinetic energy into electromagnetic energy in magnetopause generators). However, energy is extracted from the solar wind already at the bow shock, before it encounters the terrestrial magnetopause. At the bow shock the supersonic solar wind is slowed down and heated, and the region near the bow shock is known to host many complex processes, including the accelerating of particles and the generation of waves. The processes at and near the bow shock can be discussed in terms of energetics: In a generator (load) process kinetic energy is converted to (from) electromagnetic energy. Bow shock regions where the solar wind is decelerated correspond to generators, while regions where particles are energized (accelerated and heated) correspond to loads. Recently, it has been suggested that currents from the bow shock generator should flow across the magnetosheath and connect to the magnetospause current systems [Siebert and Siscoe, 2002; Lopez et al., 2011]. In this study we use data from the Magnetospheric MultiScale (MMS) mission to investigate the energetics of the bow shock and the current closure, and we compare with the MHD simulations of Lopez et al., 2011.

Study on field-aligned electrons with Cluster observation in the Earth's cusp

NASA Astrophysics Data System (ADS)

Shi, Jiankui; Torkar, Klaus; Cheng, Zhengwei

2017-04-01

Cusp region is very important to the solar wind-magnetosphere coupling. The solar wind particles, through the cusp, can directly entry into the magnetosphere and ionosphere, and transport the mass, momentum and energy. The gyrating charged particles with field-aligned velocity are significant to perform the transportation. In this study, data from Cluster observation are used to study the characteristics of field-aligned electrons (FAE's) including the downward and the upward FAEs in the cusp. We select FAE event to do analysis. The durations of the FAE event covered a wide range from 6 to 475 seconds. The FAE's were found to occur very commonly in a circumpolar zone in the polar region and the MLT and ILAT distributions showed that most of the FAE events were observed around the cusp (70-80°ILAT, 0900-1500MLT). With the FAE flux the contribution of the electrons to the Field-Aligned Current (FAC) is estimated and the result shows that the FAE was the main carrier to the FAC in the cusp. The physical mechanisms of the FAE are analyzed, namely that the downward electrons were mainly from the solar wind and the upward electrons may originated from accelerated ionospheric up-flowing electrons or mirrored solar wind electrons. The energy transportation into the magnetosphere by the solar wind electrons through the cusp is also investigated.

Efficient Scavenging of Solar and Wind Energies in a Smart City.

PubMed

Wang, Shuhua; Wang, Xue; Wang, Zhong Lin; Yang, Ya

2016-06-28

To realize the sustainable energy supply in a smart city, it is essential to maximize energy scavenging from the city environments for achieving the self-powered functions of some intelligent devices and sensors. Although the solar energy can be well harvested by using existing technologies, the large amounts of wasted wind energy in the city cannot be effectively utilized since conventional wind turbine generators can only be installed in remote areas due to their large volumes and safety issues. Here, we rationally design a hybridized nanogenerator, including a solar cell (SC) and a triboelectric nanogenerator (TENG), that can individually/simultaneously scavenge solar and wind energies, which can be extensively installed on the roofs of the city buildings. Under the same device area of about 120 mm × 22 mm, the SC can deliver a largest output power of about 8 mW, while the output power of the TENG can be up to 26 mW. Impedance matching between the SC and TENG has been achieved by using a transformer to decrease the impedance of the TENG. The hybridized nanogenerator has a larger output current and a better charging performance than that of the individual SC or TENG. This research presents a feasible approach to maximize solar and wind energies scavenging from the city environments with the aim to realize some self-powered functions in smart city.

Solar Energy Education Bibliography: Books, Films & Slides. Expanded Version.

ERIC Educational Resources Information Center

Center for Renewable Resources, Washington, DC.

This directory offers a comprehensive listing of resources, including films, for energy education. The document is divided into three sections: (1) Publications according to elementary, secondary, and college level; (2) Audiovisuals; and (3) Periodicals. Specific energy topics covered include solar, wind, and biomass technologies. (RE)

The solar wind in the third dimension

NASA Technical Reports Server (NTRS)

Neugebauer, M.

1995-01-01

For many years, solar-wind physicists have been using plasma and field data acquired near the ecliptic plane together with data on the scintillation of radio sources and remote sensing of structures in the solar corona to estimate the properties of the high-latitude solar wind, Because of the highly successful Ulysses mission, the moment of truth is now here. This talk summarizes the principal differences between the high and low latitude solar winds at the declining phase of the solar-activity cycle and between the Ulysses observations and expectations.

Potential for a Danish power system using wind energy generators, solar cells and storage

NASA Astrophysics Data System (ADS)

Blegaa, S.; Christiansen, G.

1981-10-01

Performance characteristics of a combined solar/wind power system equipped with storage and an unspecified back-up power source are studied on the basis of meteorological data in Denmark from 1959-1972. A model for annual production and storage from wind/solar installations is presented, assuming 12% efficiency for the solar cells and various power coefficients of the windmills, in addition to long and short-term storage. Noting that no correlation between wind and solar energy availability was found, and a constant ratio of 60% wind/40% solar was determined to be the optimum mix for large scale power production without taking into consideration the variations among years. It is concluded that 80-90% of the total Danish electrical load can be covered by solar/wind systems, and 100% may be possible with the addition of pumped hydroelectric storage.

Remote Sensing of the Solar Wind Density, Speed, and Temperature in the Region between the Sun and Parker Solar Probe

NASA Astrophysics Data System (ADS)

Davila, J. M.; Reginald, N. L.

2017-12-01

A coronagraph is the tool of choice to understand and observe the structure of the corona from space. The novel coronagraph concept presented her provides a new scientific capability that will allow the measurement of density, temperature, and flow velocity in the solar atmosphere. This instrument will provide the first remote sensing measurement of the global solar wind temperature, density, and flow speed in the regions between 3 and 8 Rsun. It is in this region that the manority of the solar wind acceleration takes place, and where the ion compsition of the solar wind is "frozen in". This is also the region of the corona that links the surface of the Sun to the Parker Solar Probe and to Solar Orbiter. The observations suggested here would dramatically improve our understanding of solar wind formation and evolution in this critical region.

Erosion of carbon/carbon by solar wind charged particle radiation during a solar probe mission

NASA Technical Reports Server (NTRS)

Sokolowski, Witold; O'Donnell, Tim; Millard, Jerry

1991-01-01

The possible erosion of a carbon/carbon thermal shield by solar wind-charged particle radiation is reviewed. The present knowledge of erosion data for carbon and/or graphite is surveyed, and an explanation of erosion mechanisms under different charged particle environments is discussed. The highest erosion is expected at four solar radii. Erosion rates are analytically estimated under several conservative assumptions for a normal quiet and worst case solar wind storm conditions. Mass loss analyses and comparison studies surprisingly indicate that the predicted erosion rate by solar wind could be greater than by nominal free sublimation during solar wind storm conditions at four solar radii. The predicted overall mass loss of a carbon/carbon shield material during the critical four solar radii flyby can still meet the mass loss mission requirement of less than 0.0025 g/sec.

Missing pressure in the dayside ionosphere of Venus

NASA Technical Reports Server (NTRS)

Cloutier, P. A.; Stewart, B. K.; Taylor, H. A., Jr.

1992-01-01

Data obtained by various instruments on the Pioneer-Venus spacecraft were used to study the conservation of momentum flux from the solar wind through the dayside ionopause into the thermal Venus ionosphere. A consistent pressure deficit was found below the ionopause, with a strong dependence on solar wind pressure. Independent of solar wind pressure, the pressure deficit was found to decrease with decreasing altitude below the ionopause. Measurements of this pressure deficit (missing pressure) are presented as a function of altitude for various solar wind conditions. The identity of the missing pressure component and the correlation with solar wind pressure are discussed.

IPS analysis on relationship among velocity, density and temperature of the solar wind

NASA Astrophysics Data System (ADS)

Hayashi, K.; Tokumaru, M.; Fujiki, K.

2015-12-01

The IPS(Interplanetary Scintillation)-MHD(magnetohydrodynamics) tomography is a method we have developed to determine three-dimensional MHD solution of the solar wind that best matches the line-of-sight IPS solar-wind speed data (Hayashi et al., 2003). The tomographic approach is an iteration method in which IPS observations are simulated in MHD steady-state solution, then differences between the simulated observation and the actual IPS observation is reduced by modifying solar-wind boundary map at 50 solar radii. This forward model needs to assume solar wind density and temperature as function of speed. We use empirical functions, N(V) and T(V), derived from Helios in-situ measurement data within 0.5 AU in 1970s. For recent years, especially after 2006, these functions yield higher densities and lower temperatures than in-situ measurements indicate. To characterize the differences between the simulated and actual solar wind plasma, we tune parameters in the functions so that agreements with in-situ data (near the Earth and at Ulysses) will be optimized. This optimization approach can help better simulations of the solar corona and heliosphere, and will help our understandings on roles of magnetic field in solar wind heating and acceleration.

Are current sheets the boundary of fluxtubes in the solar wind? -- A study from multiple spacecraft observation

NASA Astrophysics Data System (ADS)

Li, G.; Arnold, L.; Miao, B.; Yan, Y.

2011-12-01

G. Li (1,2), L. Arnold (1), B. Miao (3) and Y. Yan (4) (1) Department of Physics, University of Alabama in Huntsville Huntsville, AL, 35899 (2) CSPAR, University of Alabama in Huntsville Huntsville, AL, 35899 (3) School of Earth and Space Sciences, University of Science and Technology of CHINA, Hefei, China (4) Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Science, Beijing 100012, China Current sheets is a common structure in the solar wind and is a significant source of solar wind MHD turbulence intermittency. The origin of these structure is presently unknown. Non-linear interactions of the solar wind MHD turbulence can spontaneously generate these structures. On the other hand, there are proposals that these structures may represent relic structures having solar origins. Using a technique developed in [1], we examine current sheets in the solar wind from multiple spacecraft. We identify the "single-peak" and "double-peak" events in the solar wind and discuss possible scenarios for these events and its implication of the origin of the current sheets. [1] Li, G., "Identify current-sheet-like structures in the solar wind", ApJL 672, L65, 2008.

Solar Wind Five

NASA Technical Reports Server (NTRS)

Neugebauer, M. (Editor)

1983-01-01

Topics of discussion were: solar corona, MHD waves and turbulence, acceleration of the solar wind, stellar coronae and winds, long term variations, energetic particles, plasma distribution functions and waves, spatial dependences, and minor ions.

Intermittency of solar wind on scale 0.01-16 Hz.

NASA Astrophysics Data System (ADS)

Riazantseva, Maria; Zastenker, Georgy; Chernyshov, Alexander; Petrosyan, Arakel

Magnetosphere of the Earth is formed in the process of solar wind flow around earth's magnetic field. Solar wind is a flow of turbulent plasma that displays a multifractal structure and an intermittent character. That is why the study of the characteristics of solar wind turbulence is very important part of the solution of the problem of the energy transport from the solar wind to magnetosphere. A large degree of intermittency is observed in the solar wind ion flux and magnetic field time rows. We investigated the intermittency of solar wind fluctuations under large statistics of high time resolution measurements onboard Interball-1 spacecraft on scale from 0.01 to 16 Hz. Especially it is important that these investigation is carry out for the first time for the earlier unexplored (by plasma data) region of comparatively fast variations (frequency up to 16 Hz), so we significantly extend the range of intermittency observations for solar wind plasma. The intermittency practically absent on scale more then 1000 s and it grows to the small scales right up till t 30-60 s. The behavior of the intermittency for the scale less then 30-60 s is rather changeable. The boundary between these two rates of intermittency is quantitatively near to the well-known boundary between the dissipation and inertial scales of fluctuations, what may point to their possible relation. Special attention is given to a comparison of intermittency for solar wind observation intervals containing SCIF (Sudden Changes of Ion Flux) to ones for intervals without SCIF. Such a comparison allows one to reveal the fundamental turbulent properties of the solar wind regions in which SCIF is observed more frequently. We use nearly incompressible model of the solar wind turbulence for obtained data interpretation. The regime when density fluctuations are passive scalar in a hydrodynamic field of velocity is realized in turbulent solar wind flows according to this model. This hypothesis can be verified straightforwardly by investigating the density spectrum which should be slaved to the incompressible velocity spectrum. Density discontinuities on times up to t 30-60 s are defined by intermittency of velocity turbulent field. Solar wind intermittency and many or most of its discontinuities are produced by MHD turbulence in this time interval. It is possible that many or even most of the current structures in the solar wind, particularly inertial range structures that contribute to the tails of the PDFs. Complex non-gaussian behaviour on smaller times is described by dissipation rate nonhomogeneity of statistical moments for density field in a random flow.

A New Technique using Electron Velocity Data from the Four Cluster Spacecraft to Explore Magnetofluid Turbulence in the Solar Wind

NASA Technical Reports Server (NTRS)

Goldstein, Melvyn L.; Gurgiolo, C.; Fazakerley, A.; Lahiff, A.

2008-01-01

It is now possible in certain circumstances to use velocity moments computed from the Plasma Electron and Current Experiment (PEACE) on the four Cluster spacecraft to determine a number of turbulence properties of the solar wind, including direct measurements of the vorticity and compressibility. Assuming that the four spacecraft are not co-planar and that there is only a linear variation of the plasma variables across the volume defined by the four satellites, one can estimate the curl of the fluid velocity, i.e., the vorticity. From the vorticity it is possible to explore directly intermittent regions in the solar wind where dissipation is likely to be enhanced. In addition, one can estimate directly the Taylor microscale.

The electric potential of particles in interstellar space released from a nuclear waste payload

NASA Technical Reports Server (NTRS)

Williams, A. C.

1980-01-01

Mechanisms for charging a grain in the interplanetary medium include: (1) capture of solar wind electrons; (2) capture of solar wind protons; (3) ejection of electrons through the photoelectric effect due to the solar radiation; (4) escape of beta particles from beta emitters in the grain; and (5) escape of alpha particles from alpha emitters in the grain. The potentials on both nonradioactive and radioactive grains are considered with relation to particle size and time, and the distance from the Sun. Numerical results are presented where the waste mix is assumed to be PW-4b.

Solar wind composition

NASA Technical Reports Server (NTRS)

Ogilvie, K. W.; Coplan, M. A.

1995-01-01

Advances in instrumentation have resulted in the determination of the average abundances of He, C, N, O, Ne, Mg, Si, S, and Fe in the solar wind to approximately 10%. Comparisons with solar energetic particle (SEP) abundances and galactic cosmic ray abundances have revealed many similarities, especially when compared with solar photospheric abundances. It is now well established that fractionation in the corona results in an overabundance (with respect to the photosphere) of elements with first ionization potentials less than 10 eV. These observations have in turn led to the development of fractionation models that are reasonably successful in reproducing the first ionization (FIP) effect. Under some circumstances it has been possible to relate solar wind observations to particular source regions in the corona. The magnetic topologies of the source regions appear to have a strong influence on the fractionation of elements. Comparisons with spectroscopic data are particularly useful in classifying the different topologies. Ions produced from interstellar neutral atoms are also found in the solar wind. These ions are picked up by the solar wind after ionization by solar radiation or charge exchange and can be identified by their velocity in the solar wind. The pick-up ions provide most of the pressure in the interplanetary medium at large distances. Interstellar abundances can be derived from the observed fluxes of solar wind pick-up ions.

High-quality weather data for grid integration studies

NASA Astrophysics Data System (ADS)

Draxl, C.

2016-12-01

As variable renewable power penetration levels increase in power systems worldwide, renewable integration studies are crucial to ensure continued economic and reliable operation of the power grid. In this talk we will shed light on requirements for grid integration studies as far as wind and solar energy are concerned. Because wind and solar plants are strongly impacted by weather, high-resolution and high-quality weather data are required to drive power system simulations. Future data sets will have to push limits of numerical weather prediction to yield these high-resolution data sets, and wind data will have to be time-synchronized with solar data. Current wind and solar integration data sets will be presented. The Wind Integration National Dataset (WIND) Toolkit is the largest and most complete grid integration data set publicly available to date. A meteorological data set, wind power production time series, and simulated forecasts created using the Weather Research and Forecasting Model run on a 2-km grid over the continental United States at a 5-min resolution is now publicly available for more than 126,000 land-based and offshore wind power production sites. The Solar Integration National Dataset (SIND) is available as time synchronized with the WIND Toolkit, and will allow for combined wind-solar grid integration studies. The National Solar Radiation Database (NSRDB) is a similar high temporal- and spatial resolution database of 18 years of solar resource data for North America and India. Grid integration studies are also carried out in various countries, which aim at increasing their wind and solar penetration through combined wind and solar integration data sets. We will present a multi-year effort to directly support India's 24x7 energy access goal through a suite of activities aimed at enabling large-scale deployment of clean energy and energy efficiency. Another current effort is the North-American-Renewable-Integration-Study, with the aim of providing a seamless data set across borders for a whole continent, to simulate and analyze the impacts of potential future large wind and solar power penetrations on bulk power system operations.

Self consistent MHD modeling of the solar wind from coronal holes with distinct geometries

NASA Technical Reports Server (NTRS)

Stewart, G. A.; Bravo, S.

1995-01-01

Utilizing an iterative scheme, a self-consistent axisymmetric MHD model for the solar wind has been developed. We use this model to evaluate the properties of the solar wind issuing from the open polar coronal hole regions of the Sun, during solar minimum. We explore the variation of solar wind parameters across the extent of the hole and we investigate how these variations are affected by the geometry of the hole and the strength of the field at the coronal base.

Validating a magnetic reconnection model for the magnetopause

NASA Astrophysics Data System (ADS)

Schultz, Colin

2012-01-01

Originating in the Sun's million-degree corona, the solar wind flows at supersonic speeds into interplanetary space, carrying with it the solar magnetic field. As the solar wind reaches Earth's orbit, its interaction with the geomagnetic field forms the magnetosphere, a bubble-like structure within the solar wind flow that shields Earth from direct exposure to the solar wind as well as to the highly energetic charged particles produced during solar storms. Under certain orientations, the magnetic field entrained in the solar wind, known as the interplanetary magnetic field (IMF), merges with the geomagnetic field, transferring mass, momentum, and energy to the magnetosphere. The merging of these two distinct magnetic fields occurs through magnetic reconnection, a fundamental plasma-physical process that converts magnetic energy into kinetic energy and heat.

A Possible Cause of the Diminished Solar Wind During the Solar Cycle 23 - 24 Minimum

NASA Astrophysics Data System (ADS)

Liou, Kan; Wu, Chin-Chun

2016-12-01

Interplanetary magnetic field and solar wind plasma density observed at 1 AU during Solar Cycle 23 - 24 (SC-23/24) minimum were significantly smaller than those during its previous solar cycle (SC-22/23) minimum. Because the Earth's orbit is embedded in the slow wind during solar minimum, changes in the geometry and/or content of the slow wind region (SWR) can have a direct influence on the solar wind parameters near the Earth. In this study, we analyze solar wind plasma and magnetic field data of hourly values acquired by Ulysses. It is found that the solar wind, when averaging over the first (1995.6 - 1995.8) and third (2006.9 - 2008.2) Ulysses' perihelion ({˜} 1.4 AU) crossings, was about the same speed, but significantly less dense ({˜} 34 %) and cooler ({˜} 20 %), and the total magnetic field was {˜} 30 % weaker during the third compared to the first crossing. It is also found that the SWR was {˜} 50 % wider in the third ({˜} 68.5^deg; in heliographic latitude) than in the first ({˜} 44.8°) solar orbit. The observed latitudinal increase in the SWR is sufficient to explain the excessive decline in the near-Earth solar wind density during the recent solar minimum without speculating that the total solar output may have been decreasing. The observed SWR inflation is also consistent with a cooler solar wind in the SC-23/24 than in the SC-22/23 minimum. Furthermore, the ratio of the high-to-low latitude photospheric magnetic field (or equatorward magnetic pressure force), as observed by the Mountain Wilson Observatory, is smaller during the third than the first Ulysses' perihelion orbit. These findings suggest that the smaller equatorward magnetic pressure at the Sun may have led to the latitudinally-wider SRW observed by Ulysses in SC-23/24 minimum.

Kinematic Treatment of CME Evolution in the Solar Wind

NASA Technical Reports Server (NTRS)

Riley, Pete; Crooker, N. U.

2004-01-01

We present a kinematic study of the evolution of coronal mass ejections (CMEs) in the solar wind. Specifically, we consider the effects of: (1) spherical expansion; and (2) uniform expansion due to pressure gradients between the Interplanetary CME (ICME) and the ambient solar wind. We compare these results with an MHD model, which allows us to isolate these effects from the combined kinematic and dynamical effects, which are included in MHD models. They also provide compelling evidence that the fundamental cross section of so-called "force-free" flux ropes (or magnetic clouds) is neither circular or elliptical, but rather a convex-outward, "pancake" shape. We apply a force-free fitting to the magnetic vectors from the MHD simulation to assess how the distortion of the flux rope affects the fitting. In spite of these limitations, force-free fittings, which are straightforward to apply, do provide an important description of a number of parameters, including the radial dimension, orientation and chirality of the ICME.

Elemental abundances in corotating events

NASA Technical Reports Server (NTRS)

Vonrosenvinge, T. T.; Mcguire, R. E.

1986-01-01

Large, persistent solar-wind streams in 1973 and 1974 produced corotating interaction regions which accelerated particles to energies of a few MeV/nucleon. The proton to helium ratio (H/He) reported was remarkably constant at a value (22 + or - 5) equal to that in the solar wind (32 + or - 3), suggesting that particles were being accelerated directly out of the solar wind. Preliminary results from a similar study approximately 11 years (i.e., one solar cycle) later are reported. Corotating events were identified by surveying the solar wind data, energetic particle time-histories and anisotropies. This data was all obtained from the ISEE-3/ICE spacecraft. These events also show H/He ratios similar to that in the solar wind. In addition, other corotating events were examined at times when solar flare events could have injected particles into the corresponding corotating interaction regions. It was found that in these cases there is evidence for H/He ratios which are significantly different from that of the solar wind but which are consistent with the range of values found in solar flare events.

Solar Wind Helium Abundance as a Function of Speed and Heliographic Latitude: Variation through a Solar Cycle

NASA Technical Reports Server (NTRS)

Kasper, J. C.; Stenens, M. L.; Stevens, M. L.; Lazarus, A. J.; Steinberg, J. T.; Ogilvie, Keith W.

2006-01-01

We present a study of the variation of the relative abundance of helium to hydrogen in the solar wind as a function of solar wind speed and heliographic latitude over the previous solar cycle. The average values of A(sub He), the ratio of helium to hydrogen number densities, are calculated in 25 speed intervals over 27-day Carrington rotations using Faraday Cup observations from the Wind spacecraft between 1995 and 2005. The higher speed and time resolution of this study compared to an earlier work with the Wind observations has led to the discovery of three new aspects of A(sub He), modulation during solar minimum from mid-1995 to mid-1997. First, we find that for solar wind speeds between 350 and 415 km/s, A(sub He), varies with a clear six-month periodicity, with a minimum value at the heliographic equatorial plane and a typical gradient of 0.01 per degree in latitude. For the slow wind this is a 30% effect. We suggest that the latitudinal gradient may be due to an additional dependence of coronal proton flux on coronal field strength or the stability of coronal loops. Second, once the gradient is subtracted, we find that A(sub He), is a remarkably linear function of solar wind speed. Finally, we identify a vanishing speed, at which A(sub He), is zero, is 259 km/s and note that this speed corresponds to the minimum solar wind speed observed at one AU. The vanishing speed may be related to previous theoretical work in which enhancements of coronal helium lead to stagnation of the escaping proton flux. During solar maximum the A(sub He), dependences on speed and latitude disappear, and we interpret this as evidence of two source regions for slow solar wind in the ecliptic plane, one being the solar minimum streamer belt and the other likely being active regions.

Anomalously low C{sup 6+}/C{sup 5+} ratio in solar wind: ACE/SWICS observation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, L., E-mail: lzh@umich.edu; Landi, E.; Kocher, M.

The Carbon and Oxygen ionization states in the solar wind plasma freeze-in within 2 solar radii (R{sub s}) from the solar surface, and then they do not change as they propagate with the solar wind into the heliosphere. Therefore, the O{sup 7+}/O{sup 6+} and C{sup 6+}/C{sup 5+} charge state ratios measured in situ maintain a record of the thermal properties (electron temperature and density) of the inner corona where the solar wind originates. Since these two ratios freeze-in at very similar height, they are expected to be correlated. However, an investigation of the correlation between these two ratios as measuredmore » by ACE/SWICS instrument from 1998 to 201l shows that there is a subset of “Outliers” departing from the expected correlation. We find about 49.4% of these Outliers is related to the Interplanetary Coronal Mass Ejections (ICMEs), while 49.6% of them is slow speed wind (V{sub p} < 500 km/s) and about 1.0% of them is fast solar wind (V{sub p} > 500 km/s). We compare the outlier-slow-speed wind with the normal slow wind (defined as V{sub p} < 500 km/s and O{sup 7+}/O{sup 6+} > 0.2) and find that the reason that causes the Outliers to depart from the correlation is their extremely depleted C{sup 6+}/C{sup 5+} ratio which is decreased by 80% compared to the normal slow wind. We discuss the implication of the Outlier solar wind for the solar wind acceleration mechanism.« less

Solar Rotational Periodicities and the Semiannual Variation in the Solar Wind, Radiation Belt, and Aurora

NASA Technical Reports Server (NTRS)

Emery, Barbara A.; Richardson, Ian G.; Evans, David S.; Rich, Frederick J.; Wilson, Gordon R.

2011-01-01

The behavior of a number of solar wind, radiation belt, auroral and geomagnetic parameters is examined during the recent extended solar minimum and previous solar cycles, covering the period from January 1972 to July 2010. This period includes most of the solar minimum between Cycles 23 and 24, which was more extended than recent solar minima, with historically low values of most of these parameters in 2009. Solar rotational periodicities from S to 27 days were found from daily averages over 81 days for the parameters. There were very strong 9-day periodicities in many variables in 2005 -2008, triggered by recurring corotating high-speed streams (HSS). All rotational amplitudes were relatively large in the descending and early minimum phases of the solar cycle, when HSS are the predominant solar wind structures. There were minima in the amplitudes of all solar rotational periodicities near the end of each solar minimum, as well as at the start of the reversal of the solar magnetic field polarity at solar maximum (approx.1980, approx.1990, and approx. 2001) when the occurrence frequency of HSS is relatively low. Semiannual equinoctial periodicities, which were relatively strong in the 1995-1997 solar minimum, were found to be primarily the result of the changing amplitudes of the 13.5- and 27-day periodicities, where 13.5-day amplitudes were better correlated with heliospheric daily observations and 27-day amplitudes correlated better with Earth-based daily observations. The equinoctial rotational amplitudes of the Earth-based parameters were probably enhanced by a combination of the Russell-McPherron effect and a reduction in the solar wind-magnetosphere coupling efficiency during solstices. The rotational amplitudes were cross-correlated with each other, where the 27 -day amplitudes showed some of the weakest cross-correlations. The rotational amplitudes of the > 2 MeV radiation belt electron number fluxes were progressively weaker from 27- to 5-day periods, showing that processes in the magnetosphere act as a low-pass filter between the solar wind and the radiation belt. The A(sub p)/K(sub p) magnetic currents observed at subauroral latitudes are sensitive to proton auroral precipitation, especially for 9-day and shorter periods, while the A(sub p)/K(sub p) currents are governed by electron auroral precipitation for 13.5- and 27-day periodicities.

An empirical polytrope law for solar wind thermal electrons between 0.45 and 4.76 AU: Voyager 2 and Mariner 10

NASA Technical Reports Server (NTRS)

Sittler, E. C., Jr.; Scudder, J. D.

1979-01-01

Empirical evidence is presented that solar wind thermal electrons obey a polytrope law with polytrope index gamma = 1.175 plus or minus 0.03. The Voyager 2 and Mariner 10 data used as evidence are compared and discussed. The theoretical predictions that solar wind thermal electrons in the asymptotic solar wind should obey a polytrope law with polytrope index gamma = 1.16 plus or minus. The widespread impressions in the literature that solar wind electrons behave more like an isothermal than adiabatic gas, and the arguments that Coulomb collisions are the dominant stochastic process shaping observed electron distribution functions in the solar wind are reexamined, reviewed and evaluated. The assignment of the interplanetary potential as equal to approximately seven times the temperature of the thermal electrons is discussed.

Microgrid Control Strategy Utlizing Thermal Energy Storage With Renewable Solar And Wind Power Generation

DTIC Science & Technology

2016-06-01

13 Figure 6. Vertical Axis Wind Turbines and Photovoltaic Solar Panels ....................15 Figure 7. Solar Sunny Boy Inverter...16 Figure 8. Wind Turbine Inverters...1. Comparison of Energy Storage. Adapted from [16], [18], [19]. ................10 Table 2. DC Operating Voltage of Wind Turbine Inverters

Analysis of off-grid hybrid wind turbine/solar PV water pumping systems

USDA-ARS?s Scientific Manuscript database

While many remote water pumping systems exist (e.g. mechanical windmills, solar photovoltaic , wind-electric, diesel powered), very few combine both the wind and solar energy resources to possibly improve the reliability and the performance of the system. In this paper, off-grid wind turbine (WT) a...

Understanding non-equilibrium collisional and expansion effects in the solar wind with Parker Solar Probe

NASA Astrophysics Data System (ADS)

Korreck, K. E.; Klein, K. G.; Maruca, B.; Alterman, B. L.

2017-12-01

The evolution of the solar wind from the corona to the Earth and throughout the heliosphere is a complex interplay between local micro kinetics and large scale expansion effects. These processes in the solar wind need to be separated in order to understand and distinguish the dominant mechanism for heating and acceleration of the solar wind. With the upcoming launch in 2018 of Parker Solar Probe and the launch of Solar Orbiter after, addressing the local and global phenomena will be enabled with in situ measurements. Parker Solar Probe will go closer to the Sun than any previous mission enabling the ability to examine the solar wind at an early expansion age. This work examines the predictions for what will be seen inside of the 0.25 AU (54 solar radii) where Parker Solar Probe will take measurements and lays the groundwork for disentangling the expansion and collisional effects. In addition, methods of thermal plasma data analysis to determine the stability of the plasma in the Parker Solar Probe measurements will be discussed.

SOLAR WIND HEAVY IONS OVER SOLAR CYCLE 23: ACE/SWICS MEASUREMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepri, S. T.; Landi, E.; Zurbuchen, T. H.

2013-05-01

Solar wind plasma and compositional properties reflect the physical properties of the corona and its evolution over time. Studies comparing the previous solar minimum with the most recent, unusual solar minimum indicate that significant environmental changes are occurring globally on the Sun. For example, the magnetic field decreased 30% between the last two solar minima, and the ionic charge states of O have been reported to change toward lower values in the fast wind. In this work, we systematically and comprehensively analyze the compositional changes of the solar wind during cycle 23 from 2000 to 2010 while the Sun movedmore » from solar maximum to solar minimum. We find a systematic change of C, O, Si, and Fe ionic charge states toward lower ionization distributions. We also discuss long-term changes in elemental abundances and show that there is a {approx}50% decrease of heavy ion abundances (He, C, O, Si, and Fe) relative to H as the Sun went from solar maximum to solar minimum. During this time, the relative abundances in the slow wind remain organized by their first ionization potential. We discuss these results and their implications for models of the evolution of the solar atmosphere, and for the identification of the fast and slow wind themselves.« less

On the radial evolution of reflection-driven turbulence in the inner solar wind in preparation for Parker Solar Probe

NASA Astrophysics Data System (ADS)

Perez, J. C.; Chandran, B. D. G.

2017-12-01

In this work we present recent results from high-resolution direct numerical simulations and a phenomenological model that describes the radial evolution of reflection-driven Alfven Wave turbulence in the solar atmosphere and the inner solar wind. The simulations are performed inside a narrow magnetic flux tube that models a coronal hole extending from the solar surface through the chromosphere and into the solar corona to approximately 21 solar radii. The simulations include prescribed empirical profiles that account for the inhomogeneities in density, background flow, and the background magnetic field present in coronal holes. Alfven waves are injected into the solar corona by imposing random, time-dependent velocity and magnetic field fluctuations at the photosphere. The phenomenological model incorporates three important features observed in the simulations: dynamic alignment, weak/strong nonlinear AW-AW interactions, and that the outward-propagating AWs launched by the Sun split into two populations with different characteristic frequencies. Model and simulations are in good agreement and show that when the key physical parameters are chosen within observational constraints, reflection-driven Alfven turbulence is a plausible mechanism for the heating and acceleration of the fast solar wind. By flying a virtual Parker Solar Probe (PSP) through the simulations, we will also establish comparisons between the model and simulations with the kind of single-point measurements that PSP will provide.

Spacecraft measurements of the elemental and isotopic composition of solar energetic particles

NASA Technical Reports Server (NTRS)

Mewaldt, R. A.

1980-01-01

Within the past few years, instruments flown on satellites and space probes have made significant progress in measuring the elemental and isotopic composition of energetic heavy nuclei accelerated in solar flares. These new observations are discussed, focusing on: (1) the energy dependence of the elemental composition at energies not greater than 1 MeV/nucleon; (2) flare to flare variations in the composition; and (3) comparisons of the average solar particle abundances (Z not less than 2 and not greater than 28) with other measures of the solar composition, including photospheric, coronal, and solar wind observations. These comparisons have led to the suggestion that solar flares sample the composition of the corona. Isotopic measurements of heavy solar flare nuclei have recently added a new dimension to these studies. In particular, the isotopic composition of solar flare neon has been found to be significantly different from that measured in the solar wind, but consistent with the meteoritic component neon-A.

Properties of Minor Ions In the Solar Wind and Implications for the Background Solar Wind Plasma

NASA Technical Reports Server (NTRS)

Esser, Ruth; Wagner, William (Technical Monitor)

2002-01-01

Ion charge states measured in situ in interplanetary space carry information on the properties of the solar wind plasma in the inner corona. The goal of the proposal is to determine coronal plasma conditions that produce the in situ observed charge states. This study is carried out using solar wind models, coronal observations, ion fraction calculations and in situ observations.

Asteroid surface processes: Experimental studies of the solar wind on reflectance and optical properties of asteroids

NASA Technical Reports Server (NTRS)

Mcfadden, Lucy-Ann

1991-01-01

The effect of the solar wind on the optical properties of meteorites was studied to determine whether the solar wind can alter the properties of ordinary chondrite parent bodies resulting in the spectral properties of S-type asteroids. The existing database of optical properties of asteroids was analyzed to determine the effect of solar wind in altering asteroid surface properties.

Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles

NASA Astrophysics Data System (ADS)

Li, X.; Baker, D. N.; Zhao, H.; Zhang, K.; Jaynes, A. N.; Schiller, Q.; Kanekal, S. G.; Blake, J. B.; Temerin, M.

2017-05-01

Long-term (>2 solar cycles) measurements reveal that MeV electron fluxes, solar wind speed, and geomagnetic activity have been extremely low during this current solar cycle, including years before and during the Van Allen Probes era. This study examines solar wind speed, the geomagnetic storm index (Dst), >2 MeV electrons at geostationary orbit, and 2 MeV electrons across various L shells measured by Solar Anomalous Magnetospheric Particle Explorer in low Earth orbit (LEO) and by the Van Allen Probes/Relativistic Electron and Proton Telescope (REPT) in a geotransfer-like orbit; the latter measurements are normalized to LEO based on comparison with Colorado Student Space Weather Experiment/Relativistic Electron and Proton Telescope integrated little experiment (REPTile) measurements in LEO. The average ratio of REPTile/REPT varies in a systematic manner with L, 16% at L = 2.7, decreasing with L and reaching 0.7% at L = 4.7, and increasing again with L though with greater uncertainty. We show that there have been no 2 MeV electron enhancements inside L 2.6 since 2006, prior to which numerous penetrations of 2 MeV electrons into L < 2.5 were measured during periods of stronger solar wind conditions (in terms of high-speed solar wind, magnitude of interplanetary magnetic field, B, and a sustained southward Bz) and thus stronger geomagnetic activity. We conclude that results from the Van Allen Probes, which have been providing the finest measurements but in operation during a quiet solar activity period, may not be representative of radiation belt dynamics, particularly for the inner edge of the outer belt, during other solar cycle phases.

Microphysics of Waves and Instabilities in the Solar Wind and their Macro Manifestations in the Corona and Interplanetary Space

NASA Technical Reports Server (NTRS)

Habbal, Shadia R.; Gurman, Joseph (Technical Monitor)

2003-01-01

Investigations of the physical processes responsible for the acceleration of the solar wind were pursued with the development of two new solar wind codes: a hybrid code and a 2-D MHD code. Hybrid simulations were performed to investigate the interaction between ions and parallel propagating low frequency ion cyclotron waves in a homogeneous plasma. In a low-beta plasma such as the solar wind plasma in the inner corona, the proton thermal speed is much smaller than the Alfven speed. Vlasov linear theory predicts that protons are not in resonance with low frequency ion cyclotron waves. However, non-linear effect makes it possible that these waves can strongly heat and accelerate protons. This study has important implications for study of the corona and the solar wind. Low frequency ion cyclotron waves or Alfven waves are commonly observed in the solar wind. Until now, it is believed that these waves are not able to heat the solar wind plasma unless some cascading processes transfer the energy of these waves to high frequency part. However, this study shows that these waves may directly heat and accelerate protons non-linearly. This process may play an important role in the coronal heating and the solar wind acceleration, at least in some parameter space.

Wind and solar resource data sets: Wind and solar resource data sets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clifton, Andrew; Hodge, Bri-Mathias; Draxl, Caroline

The range of resource data sets spans from static cartography showing the mean annual wind speed or solar irradiance across a region to high temporal and high spatial resolution products that provide detailed information at a potential wind or solar energy facility. These data sets are used to support continental-scale, national, or regional renewable energy development; facilitate prospecting by developers; and enable grid integration studies. This review first provides an introduction to the wind and solar resource data sets, then provides an overview of the common methods used for their creation and validation. A brief history of wind and solarmore » resource data sets is then presented, followed by areas for future research.« less

Forecasting Kp from solar wind data: input parameter study using 3-hour averages and 3-hour range values

NASA Astrophysics Data System (ADS)

Wintoft, Peter; Wik, Magnus; Matzka, Jürgen; Shprits, Yuri

2017-11-01

We have developed neural network models that predict Kp from upstream solar wind data. We study the importance of various input parameters, starting with the magnetic component Bz, particle density n, and velocity V and then adding total field B and the By component. As we also notice a seasonal and UT variation in average Kp we include functions of day-of-year and UT. Finally, as Kp is a global representation of the maximum range of geomagnetic variation over 3-hour UT intervals we conclude that sudden changes in the solar wind can have a big effect on Kp, even though it is a 3-hour value. Therefore, 3-hour solar wind averages will not always appropriately represent the solar wind condition, and we introduce 3-hour maxima and minima values to some degree address this problem. We find that introducing total field B and 3-hour maxima and minima, derived from 1-minute solar wind data, have a great influence on the performance. Due to the low number of samples for high Kp values there can be considerable variation in predicted Kp for different networks with similar validation errors. We address this issue by using an ensemble of networks from which we use the median predicted Kp. The models (ensemble of networks) provide prediction lead times in the range 20-90 min given by the time it takes a solar wind structure to travel from L1 to Earth. Two models are implemented that can be run with real time data: (1) IRF-Kp-2017-h3 uses the 3-hour averages of the solar wind data and (2) IRF-Kp-2017 uses in addition to the averages, also the minima and maxima values. The IRF-Kp-2017 model has RMS error of 0.55 and linear correlation of 0.92 based on an independent test set with final Kp covering 2 years using ACE Level 2 data. The IRF-Kp-2017-h3 model has RMSE = 0.63 and correlation = 0.89. We also explore the errors when tested on another two-year period with real-time ACE data which gives RMSE = 0.59 for IRF-Kp-2017 and RMSE = 0.73 for IRF-Kp-2017-h3. The errors as function of Kp and for different years are also studied.

Interplanetary gas. XX - Does the radial solar wind speed increase with latitude

NASA Technical Reports Server (NTRS)

Brandt, J. C.; Harrington, R. S.; Roosen, R. G.

1975-01-01

The astrometric technique used to derive solar wind speeds from ionic comet-tail orientations has been used to test the suggestion that the radial solar wind speed is higher near the solar poles than near the equator. We find no evidence for the suggested latitude variation.

75 FR 59291 - In the Matter of: Certain Wind and Solar-Powered Light Posts and Street Lamps; Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-27

... INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-736] In the Matter of: Certain Wind and Solar... solar-powered light posts and street lamps by reason of infringement of the claimed design of U.S... certain wind and solar- [[Page 59292

A meeting with the universe: Science discoveries from the space program

NASA Technical Reports Server (NTRS)

French, B. M. (Editor); Maran, S. P. (Editor)

1981-01-01

A general history of space exploration is presented. The solar system is discussed. The Sun-Earth relationship is considered, including magnetic fields, solar wind, the magnetosphere, and the Sun-weather relationship. The universe beyond the solar system is discussed. Topics include stellar and galactic evolution, quasars and intergalactic space. The effects of weightlessness and ionizing radiation on human beings are considered. The possibility of extraterrestrial life is discussed. Lunar and planetary exploration, solar-terrestrial physics, astrophysics, biomedical research and exobiology are reviewed. Numerons color illustrations are included.

A meeting with the universe: Science discoveries from the space program

NASA Astrophysics Data System (ADS)

French, Bevan M.; Maran, Stephen P.; Chipman, Eric G.

A general history of space exploration is presented. The solar system is discussed. The Sun-Earth relationship is considered, including magnetic fields, solar wind, the magnetosphere, and the Sun-weather relationship. The universe beyond the solar system is discussed. Topics include stellar and galactic evolution, quasars and intergalactic space. The effects of weightlessness and ionizing radiation on human beings are considered. The possibility of extraterrestrial life is discussed. Lunar and planetary exploration, solar-terrestrial physics, astrophysics, biomedical research and exobiology are reviewed. Numerous color illustrations are included.

Taking Venus models to new dimensions.

NASA Astrophysics Data System (ADS)

Murawski, K.

1997-11-01

Space plasma physicists in Poland and Japan have gained new insights into the interaction between the solar wind and Venus. Computer simulations of this 3D global interaction between the solar wind and nonmagnetized bodies have enabled greater understanding of the large-scale processes involved in such phenomena. A model that offers improved understanding of the solar wind interaction with Venus (as well as other nonmagnetized bodies impacted by the solar wind) has been developed. In this model, the interaction of the solar wind with the ionosphere of Venus is studied by calculating numerical solutions of the 3D MHD equations for two-component, chemically reactive plasma. The author describes the innovative model.

Ion Isotropy and Ion Resonant Waves in the Solar Wind: Cassini Observations

NASA Technical Reports Server (NTRS)

Kellogg, Paul J.; Gurnett, Donald A.; Hospodarsky, George B.; Kurth, William S.

2001-01-01

Electric fields in the solar wind, in the range of one Hertz, are reported for the first time from a 3-axis stabilized spacecraft. The measurements are made with the Radio and Plasma Wave System (RPWS) experiment on the Cassini spacecraft. Kellogg suggested that such waves could be important in maintaining the near-isotropy of solar wind ions and the validity of MHD for the description of the solar wind. The amplitudes found are larger than those estimated by Kellogg from other measurements, and are due to quasi-electrostatic waves. These amplitudes are quite sufficient to maintain isotropy of the solar wind ions.

A Conspectus on US Energy

NASA Astrophysics Data System (ADS)

Hayden, Howard

2009-05-01

Until about 1850, the energy used in the US came almost exclusively from firewood. Now we use petroleum, coal, natural gas, nuclear fission, indirect solar energy (biomass, hydro, and wind), geothermal energy, and direct solar energy (solar/thermal, solar/thermal/electric, and photovoltaics). Compared to our ancestors in 1850, we use over 40 times as much energy, of which only about 6 percent is from solar sources, versus 100% in 1850. On a per-capita basis we use about 3.1 times as much energy, in spite of the modern conveniences that to Abraham Lincoln would seem unthinkably lavish. The US uses about 107 EJ of primary energy annually, equivalent to 3.4 TW around-the-clock average power. About 40 percent of that energy goes toward production of electricity. Approximately 2 EJ of heat is obtained from combined heat-and-power plants that produce about 10^9 kWh (3.6 PJ) of electricity. (N.B.: hydro and wind do not involve heat-to-work conversion. By custom, the electrical energy produced by wind and hydro is multiplied by about 3 to generate an as-if quantity of primary energy.) When account is taken of how the electricity is distributed, industry uses 33 percent of the primary energy, followed by transportation (28%), residences (21%), and commercial establishments (18%). ``Fossil fuels'' (coal, oil, and natural gas) account for about 85 percent of our primary energy. Nuclear energy accounts for about 8%. Biomass and hydro, the venerable solar-derived sources, account for about 7%. Geothermal, wind, and direct solar energy account for about 0.4%. This talk will discuss prospects for various alternative sources, including nuclear fission and T. Boone Pickens' plan to displace imported petroleum indirectly by substituting wind for natural gas.

The effect of the hot oxygen corona on the interaction of the solar wind with Venus

NASA Technical Reports Server (NTRS)

Belotserkovskii, O. M.; Mitnitskii, V. IA.; Breus, T. K.; Krymskii, A. M.; Nagy, A. F.

1987-01-01

A numerical gasdynamic model, which includes the effects of mass loading of the shocked solar wind, was used to calculate the density and magnetic field variations in the magnetosheath of Venus. These calculations were carried out for conditions corresponding to a specific orbit of the Pioneer Venus Orbiter (PVO orbit 582). A comparison of the model predictions and the measured shock position, density and magnetic field values showed a reasonable agreement, indicating that a gasdynamic model that includes the effects of mass loading can be used to predict these parameters.

The effect of the hot oxygen corona on the interaction of the solar wind with Venus

NASA Astrophysics Data System (ADS)

Belotserkovskii, O. M.; Breus, T. K.; Krymskii, A. M.; Mitnitskii, V. Ya.; Nagey, A. F.; Gombosi, T. I.

1987-05-01

A numerical gas dynamic model, which includes the effects of mass loading of the shocked solar wind, was used to calculate the density and magnetic field variations in the magnetosheath of Venus. These calculations were carried out for conditions corresponding to a specific orbit of the Pioneer Venus Orbiter (PVO orbit 582). A comparison of the model predictions and the measured shock position, density and magnetic field values showed a reasonable agreement, indicating that a gas dynamic model that includes the effects of mass loading can be used to predict these parameters.

Studies of Interstellar Pickup Ions in the Solar Wind

NASA Technical Reports Server (NTRS)

Isenberg, Philip A.; Lee, Martin A.; Mobius, Eberhard

1996-01-01

The work under this grant involves studies of the interaction of interstellar pickup ions with the solar wind, with the goal of a comprehensive model of the particle distributions and wave intensities to be expected throughout the heliosphere, as well as the interactions of those distributions with the solar wind termination shock. In the past year, we have completed a number of projects, including observations and modeling of the effects of a large scattering mean free path on the pickup He(+) seen at AMPTE, an analytical model of anisotropic pickup tons in a steady radial magnetic field, and a derivation of a reduced solar wind Mach number due to increased estimates on the inflowing hydrogen density allowing for a weak termination shock. In the next year, we plan to investigate in more detail the correspondence between our models of anisotropic pickup ions and the data on spectra, variations, and proton-He(+) correlation provided by AMPTE, Ulysses, and our instrument on SOHO. We will model the time-dependent pickup ion density resulting from finite periods of radial magnetic field. We will also incorporate the effects of a large mean free path into our analysis of the He(+) focusing cone, leading to more accurate parameter values for the interstellar helium gas. This progress report also includes a discussion of our Space Physics Educational Outreach activities in the past year and plans for the next year.

Modeling solar wind with boundary conditions from interplanetary scintillations

DOE PAGES

Manoharan, P.; Kim, T.; Pogorelov, N. V.; ...

2015-09-30

Interplanetary scintillations make it possible to create three-dimensional, time- dependent distributions of the solar wind velocity. Combined with the magnetic field observations in the solar photosphere, they help perform solar wind simulations in a genuinely time-dependent way. Interplanetary scintillation measurements from the Ooty Radio Astronomical Observatory in India provide directions to multiple stars and may assure better resolution of transient processes in the solar wind. In this paper, we present velocity distributions derived from Ooty observations and compare them with those obtained with the Wang-Sheeley-Arge (WSA) model. We also present our simulations of the solar wind flow from 0.1 AUmore » to 1 AU with the boundary conditions based on both Ooty and WSA data.« less

Solar wind velocity and temperature in the outer heliosphere

NASA Technical Reports Server (NTRS)

Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.

1994-01-01

At the end of 1992, the Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were at heliocentric distances of 56.0, 37.3, and 39.0 AU and heliographic latitudes of 3.3 deg N, 17.4 deg N, and 8.6 deg S, respectively. Pioneer 11 and Voyager 2 are at similar celestial longitudes, while Pioneer 10 is on the opposite side of the Sun. All three spacecraft have working plasma analyzers, so intercomparison of data from these spacecraft provides important information about the global character of the solar wind in the outer heliosphere. The averaged solar wind speed continued to exhibit its well-known variation with solar cycle: Even at heliocentric distances greater than 50 AU, the average speed is highest during the declining phase of the solar cycle and lowest near solar minimum. There was a strong latitudinal gradient in solar wind speed between 3 deg and 17 deg N during the last solar minimum, but this gradient has since disappeared. The solar wind temperature declined with increasing heliocentric distance out to a heliocentric distance of at least 20 AU; this decline appeared to continue at larger heliocentric distances, but temperatures in the outer heliosphere were suprisingly high. While Pioneer 10 and Voyager 2 observed comparable solar wind temperatures, the temperature at Pioneer 11 was significantly higher, which suggests the existence of a large-scale variation of temperature with heliographic longitude. There was also some suggestion that solar wind temperatures were higher near solar minimum.

SMILE: A new approach to exploring solar-terrestrial relationships

NASA Astrophysics Data System (ADS)

Branduardi-Raymont, Graziella; Wang, Chi; Steven, Sembay; Dai, Lei; Li, Lei; Donovan, Eric; Sun, Tianran; Kataria, Dhiren; Yang, Huigen; Read, Andrew; Whittaker, Ian; Spanswick, Emma; Sibeck, David; Kuntz, Kip; Escoubet, Philippe; Agnolon, David; Raab, Walfried; Zheng, Janhua

2017-04-01

SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) aims to investigate the coupling of the solar wind with the Earth's magnetosphere, and the geospace dynamics that ensue, in a novel and global manner never tried so far. From a highly elliptical and highly inclined polar orbit, SMILE will simultaneously image the soft X-rays produced by solar wind charge exchange to delineate the Earth's magnetic boundaries and polar cusps, image the northern auroral oval in ultraviolet emissions, and measure the solar wind/magnetosheath plasma and magnetic field input. SMILE measurements will inform the science underpinning our still limited understanding of solar-terrestrial relationships and of their fundamental drivers, and will validate both global empirical and first-principle models. For the first time we will be able to trace and link the processes governing magnetopause interactions to those causing charged particle precipitation into the cusps and the remainder of the auroral oval, mapping aspects of the global interaction including the evolution of energy and mass transport. SMILE is a joint space mission between the European Space Agency and the Chinese Academy of Sciences due for launch at the end of 2021. This presentation will cover the science that will be delivered by SMILE and will provide an overview of SMILE's payload and mission development, demonstrating the scientific potential of SMILE through simulations of the data that it will return.

Ions with low charges in the solar wind as measured by SWICS on board Ulysses. [Solar Wind Ion Composition Spectrometer

NASA Technical Reports Server (NTRS)

Geiss, J.; Ogilvie, K. W.; Von Steiger, R.; Mall, U.; Gloeckler, G.; Galvin, A. B.; Ipavich, F.; Wilken, B.; Gliem, F.

1992-01-01

We present new data on rare ions in the solar wind. Using the Ulysses-SWICS instrument with its very low background we have searched for low-charge ions during a 6-d period of low-speed solar wind and established sensitive upper limits for many species. In the solar wind, we found He(1+)/He(2+) of less than 5 x 10 exp -4. This result and the charge state distributions of heavier elements indicate that all components of the investigated ion population went through a regular coronal expansion and experienced the typical electron temperatures of 1 to 2 million Kelvin. We argue that the virtual absence of low-charge ions demonstrates a very low level of nonsolar contamination in the source region of the solar wind sample we studied. Since this sample showed the FlP effect typical for low-speed solar wind, i.e., an enhancement in the abundances of elements with low first ionization potential, we conclude that this enhancement was caused by an ion-atom separation mechanism operating near the solar surface and not by foreign material in the corona.

Dynamics of Magnetopause Reconnection in Response to Variable Solar Wind Conditions

NASA Astrophysics Data System (ADS)

Berchem, J.; Richard, R. L.; Escoubet, C. P.; Pitout, F.

2017-12-01

Quantifying the dynamics of magnetopause reconnection in response to variable solar wind driving is essential to advancing our predictive understanding of the interaction of the solar wind/IMF with the magnetosphere. To this end we have carried out numerical studies that combine global magnetohydrodynamic (MHD) and Large-Scale Kinetic (LSK) simulations to identify and understand the effects of solar wind/IMF variations. The use of the low dissipation, high resolution UCLA MHD code incorporating a non-linear local resistivity allows the representation of the global configuration of the dayside magnetosphere while the use of LSK ion test particle codes with distributed particle detectors allows us to compare the simulation results with spacecraft observations such as ion dispersion signatures observed by the Cluster spacecraft. We present the results of simulations that focus on the impacts of relatively simple solar wind discontinuities on the magnetopause and examine how the recent history of the interaction of the magnetospheric boundary with solar wind discontinuities can modify the dynamics of magnetopause reconnection in response to the solar wind input.

Sputtering by the Solar Wind: Effects of Variable Composition

NASA Technical Reports Server (NTRS)

Killen, R. M.; Arrell, W. M.; Sarantos, M.; Delory, G. T.

2011-01-01

It has long been recognized that solar wind bombardment onto exposed surfaces in the solar system will produce an energetic component to the exospheres about those bodies. Laboratory experiments have shown that there is no increase in the sputtering yield caused by highly charged heavy ions for metallic and for semiconducting surfaces, but the sputter yield can be noticeably increased in the case of a good insulating surface. Recently measurements of the solar wind composition have become available. It is now known that the solar wind composition is highly dependent on the origin of the particular plasma. Using the measured composition of the slow wind, fast wind, solar energetic particle (SEP) population, and coronal mass ejection (CME), broken down into its various components, we have estimated the total sputter yield for each type of solar wind. Whereas many previous calculations of sputtering were limited to the effects of proton bombardment. we show that the heavy ion component. especially the He++ component. can greatly enhance the total sputter yield during times when the heavy ion population is enhanced. We will discuss sputtering of both neutrals and ions.

Multi objective decision making in hybrid energy system design

NASA Astrophysics Data System (ADS)

Merino, Gabriel Guillermo

The design of grid-connected photovoltaic wind generator system supplying a farmstead in Nebraska has been undertaken in this dissertation. The design process took into account competing criteria that motivate the use of different sources of energy for electric generation. The criteria considered were 'Financial', 'Environmental', and 'User/System compatibility'. A distance based multi-objective decision making methodology was developed to rank design alternatives. The method is based upon a precedence order imposed upon the design objectives and a distance metric describing the performance of each alternative. This methodology advances previous work by combining ambiguous information about the alternatives with a decision-maker imposed precedence order in the objectives. Design alternatives, defined by the photovoltaic array and wind generator installed capacities, were analyzed using the multi-objective decision making approach. The performance of the design alternatives was determined by simulating the system using hourly data for an electric load for a farmstead and hourly averages of solar irradiation, temperature and wind speed from eight wind-solar energy monitoring sites in Nebraska. The spatial variability of the solar energy resource within the region was assessed by determining semivariogram models to krige hourly and daily solar radiation data. No significant difference was found in the predicted performance of the system when using kriged solar radiation data, with the models generated vs. using actual data. The spatial variability of the combined wind and solar energy resources was included in the design analysis by using fuzzy numbers and arithmetic. The best alternative was dependent upon the precedence order assumed for the main criteria. Alternatives with no PV array or wind generator dominated when the 'Financial' criteria preceded the others. In contrast, alternatives with a nil component of PV array but a high wind generator component, dominated when the 'Environment' objective or the 'User/System compatibility' objectives were more important than the 'Financial' objectives and they also dominated when the three criteria were considered equally important.

An MHD Code for the Study of Magnetic Structures in the Solar Wind

NASA Technical Reports Server (NTRS)

Allred, J. C.; MacNeice, P. J.

2015-01-01

We have developed a 2.5D MHD code designed to study how the solar wind influences the evolution of transient events in the solar corona and inner heliosphere. The code includes thermal conduction, coronal heating and radiative cooling. Thermal conduction is assumed to be magnetic field-aligned in the inner corona and transitions to a collisionless formulation in the outer corona. We have developed a stable method to handle field-aligned conduction around magnetic null points. The inner boundary is placed in the upper transition region, and the mass flux across the boundary is determined from 1D field-aligned characteristics and a 'radiative energy balance' condition. The 2.5D nature of this code makes it ideal for parameter studies not yet possible with 3D codes. We have made this code publicly available as a tool for the community. To this end we have developed a graphical interface to aid in the selection of appropriate options and a graphical interface that can process and visualize the data produced by the simulation. As an example, we show a simulation of a dipole field stretched into a helmet streamer by the solar wind. Plasmoids periodically erupt from the streamer, and we perform a parameter study of how the frequency and location of these eruptions changed in response to different levels of coronal heating. As a further example, we show the solar wind stretching a compact multi-polar flux system. This flux system will be used to study breakout coronal mass ejections in the presence of the solar wind.

The Slow and Fast Solar Wind Boundary, Corotating Interaction Regions, and Coronal Mass Ejection observations with Solar Probe Plus and Solar Orbiter (Invited)

NASA Astrophysics Data System (ADS)

Velli, M. M.

2013-12-01

The Solar Probe Plus and Solar Orbiter missions have as part of their goals to understand the source regions of the solar wind and of the heliospheric magnetic field. In the heliosphere, the solar wind is made up of interacting fast and slow solar wind streams as well as a clearly intermittent source of flow and field, arising from coronal mass ejections (CMEs). In this presentation a summary of the questions associated with the distibution of wind speeds and magnetic fields in the inner heliosphere and their origin on the sun will be summarized. Where and how does the sharp gradient in speeds develop close to the Sun? Is the wind source for fast and slow the same, and is there a steady component or is its origin always intermittent in nature? Where does the heliospheric current sheet form and how stable is it close to the Sun? What is the distribution of CME origins and is there a continuum from large CMEs to small blobs of plasma? We will describe our current knowledge and discuss how SPP and SO will contribute to a more comprehensive understanding of the sources of the solar wind and magnetic fields in the heliosphere.

The temperature of quiescent streamers during solar cycles 23 and 24

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landi, E.; Testa, P.

2014-05-20

Recent in-situ determinations of the temporal evolution of the charge state distribution in the fast and slow solar wind have shown a general decrease in the degree of ionization of all the elements in the solar wind along solar cycles 23 and 24. Such a decrease has been interpreted as a cooling of the solar corona which occurred during the decline and minimum phase of solar cycle 23 from 2000 to 2010. In the present work, we investigate whether spectroscopic determinations of the temperature of the quiescent streamers show signatures of coronal plasma cooling during cycles 23 and 24. Wemore » measure the coronal electron density and thermal structure at the base of 60 quiescent streamers observed from 1996 to 2013 by SOHO/SUMER and Hinode/EIS and find that both quantities do now show any significant dependence on the solar cycle. We argue that if the slow solar wind is accelerated from the solar photosphere or chromosphere, the measured decrease in the in-situ wind charge state distribution might be due to an increased efficiency in the wind acceleration mechanism at low altitudes. If the slow wind originates from the corona, a combination of density and wind acceleration changes may be responsible for the in-situ results.« less

Global ICME-Mars Interaction and Induced Atmospheric Loss

NASA Astrophysics Data System (ADS)

Fang, X.; Ma, Y.; Manchester, W.

2013-12-01

Without the shielding of a strong intrinsic magnetic field, the present-day Mars atmosphere is more vulnerable to external solar wind forcing than the Earth's atmosphere. Therefore interplanetary coronal mass ejections (ICMEs) are expected to drive disturbances in the Mars environment in a profoundly different way, which, however, is poorly understood due to the lack of coordinated solar wind and Mars observations. In this study, three sophisticated models work in concert to simulate the physical domain extending from the solar corona to near-Mars space for the 13 May 2005 ICME event. The Space Weather Modeling Framework (SWMF) will be used to investigate the interaction of the ICME with the ambient solar wind and monitor its propagation from the Sun to the planet. A 3-D MHD model for Mars will be applied to assess the planetary atmospheric/ionospheric responses during the ICME passage of Mars. In the Mars weak magnetic field environment, the ion kinetic effects are important and will be included through the use of a 3-D Monte Carlo pickup ion transport model. These physics-based modeling efforts enable us to provide a global and time series view of the Mars response to transient solar wind disturbances and induced atmospheric loss, which is currently not possible due to the limitation of observations.

3D numerical study of the propagation characteristics of a consequence of coronal mass ejections in a structured ambient solar wind

NASA Astrophysics Data System (ADS)

Zhou, Y.; Feng, X. S.

2015-12-01

CMEs have been identified as a prime causal link between solar activity and large, nonrecurrent geomagnetic storm. In order to improve geomagnetic storm predictions, a careful study of CME's propagation characteristics is important. Here, we analyze and quantitatively study the evolution and propagation characteristics of coronal mass ejections (CMEs) launched at several positions into a structured real ambient solar wind by using a three-dimensional (3D) numerical magnetohydrodynamics (MHD) simulation. The ambient solar wind structure during Carrington rotation 2095 is selected, which is an appropriate around activity minimum and declining phase. The CME is initiated by a simple spherical plasmoid model: a spheromak magnetic structure with high speed, high pressure and high plasma density plasmoid. We present a detailed analysis of the plasma, magnetic field, geoeffectiveness, and composition signatures of these CMEs. Results show that the motion and local appearance of a CME in interplanetary space is strongly affected by its interaction with the background solar wind structure, including its velocity, density, and magnetic structures. The simulations show that the initial launched position substantially affects the IP evolution of the CMEs influencing the propagation velocity, the shape, the trajectory and even the geo-effectiveness

Contribution of wind energy to the energy balance of a combined solar and wind energy system. Part 1: System description, data acquisition and system performance

NASA Astrophysics Data System (ADS)

Ferger, R.; Machens, U.

1985-05-01

A one-family house was equipped with a combined solar and wind energy system plus a night storage heater to measure the seasonal complementary contribution of wind and solar energy to energy demand. Project implementation, problems encountered and modifications to the initial system are described. Meteorological and operational data and house consumption data were recorded on computer-based measuring system. Data on the combined effects of and interdependence between solar collector and wind energy converter are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Heather A.; McComas, David J.; DeForest, Craig E.

We examine the long-term time evolution (1965–2015) of the relationships between solar wind proton temperature ( T {sub p}) and speed ( V {sub p}) and between the proton density ( n {sub p}) and speed using OMNI solar wind observations taken near Earth. We find a long-term decrease in the proton temperature–speed ( T {sub p}– V {sub p}) slope that lasted from 1972 to 2010, but has been trending upward since 2010. Since the solar wind proton density–speed ( n {sub p}– V {sub p}) relationship is not linear like the T {sub p}– V {sub p} relationship,more » we perform power-law fits for n {sub p}– V {sub p}. The exponent (steepness in the n {sub p}– V {sub p} relationship) is correlated with the solar cycle. This exponent has a stronger correlation with current sheet tilt angle than with sunspot number because the sunspot number maxima vary considerably from cycle to cycle and the tilt angle maxima do not. To understand this finding, we examined the average n {sub p} for different speed ranges, and found that for the slow wind n {sub p} is highly correlated with the sunspot number, with a lag of approximately four years. The fast wind n {sub p} variation was less, but in phase with the cycle. This phase difference may contribute to the n {sub p}– V {sub p} exponent correlation with the solar cycle. These long-term trends are important since empirical formulas based on fits to T {sub p} and V {sub p} data are commonly used to identify interplanetary coronal mass ejections, but these formulas do not include any time dependence. Changes in the solar wind density over a solar cycle will create corresponding changes in the near-Earth space environment and the overall extent of the heliosphere.« less

77 FR 72439 - Residential, Business, and Wind and Solar Resource Leases on Indian Land

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-05

... Affairs 25 CFR Part 162 Residential, Business, and Wind and Solar Resource Leases on Indian Land; Final...-2011-0001] RIN 1076-AE73 Residential, Business, and Wind and Solar Resource Leases on Indian Land... adds new regulations to address residential leases, business leases, wind energy evaluation leases, and...

On Solar Wind Origin and Acceleration: Measurements from ACE

NASA Astrophysics Data System (ADS)

Stakhiv, Mark; Lepri, Susan T.; Landi, Enrico; Tracy, Patrick; Zurbuchen, Thomas H.

2016-10-01

The origin and acceleration of the solar wind are still debated. In this paper, we search for signatures of the source region and acceleration mechanism of the solar wind in the plasma properties measured in situ by the Advanced Composition Explorer spacecraft. Using the elemental abundances as a proxy for the source region and the differential velocity and ion temperature ratios as a proxy for the acceleration mechanism, we are able to identify signatures pointing toward possible source regions and acceleration mechanisms. We find that the fast solar wind in the ecliptic plane is the same as that observed from the polar regions and is consistent with wave acceleration and coronal-hole origin. We also find that the slow wind is composed of two components: one similar to the fast solar wind (with slower velocity) and the other likely originating from closed magnetic loops. Both components of the slow solar wind show signatures of wave acceleration. From these findings, we draw a scenario that envisions two types of wind, with different source regions and release mechanisms, but the same wave acceleration mechanism.

ON SOLAR WIND ORIGIN AND ACCELERATION: MEASUREMENTS FROM ACE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stakhiv, Mark; Lepri, Susan T.; Landi, Enrico

The origin and acceleration of the solar wind are still debated. In this paper, we search for signatures of the source region and acceleration mechanism of the solar wind in the plasma properties measured in situ by the Advanced Composition Explorer spacecraft. Using the elemental abundances as a proxy for the source region and the differential velocity and ion temperature ratios as a proxy for the acceleration mechanism, we are able to identify signatures pointing toward possible source regions and acceleration mechanisms. We find that the fast solar wind in the ecliptic plane is the same as that observed frommore » the polar regions and is consistent with wave acceleration and coronal-hole origin. We also find that the slow wind is composed of two components: one similar to the fast solar wind (with slower velocity) and the other likely originating from closed magnetic loops. Both components of the slow solar wind show signatures of wave acceleration. From these findings, we draw a scenario that envisions two types of wind, with different source regions and release mechanisms, but the same wave acceleration mechanism.« less

78 FR 67138 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-08

... Solar 1, LLC, Copper Mountain Solar 2, LLC, Energia Sierra Juarez U.S., LLC, Flat Ridge 2 Wind Energy LLC, Fowler Ridge II Wind Farm LLC, Mehoopany Wind Energy LLC, Mesquite Power, LLC, Mesquite Solar 1...

High coronal structure of high velocity solar wind stream sources

NASA Technical Reports Server (NTRS)

Nolte, J. T.; Krieger, A. S.; Roelof, E. C.; Gold, R. E.

1977-01-01

It is shown analytically that the transition from a high-speed stream source to the ambient coronal conditions is quite rapid in longitude in the high corona. This sharp eastern coronal boundary for the solar wind stream sources is strongly suggested by the solar wind 'dwells' which appear in plots of solar wind velocity against constant-radial-velocity-approximation source longitudes. The possibility of a systematic velocity-dependent effect in the constant-radial-velocity approximation, which would cause this boundary to appear sharper than it is, is investigated. A velocity-dependent interplanetary propagation effect or a velocity-dependent 'source altitude' are two possible sources of such a systematic effect. It is shown that, for at least some dwells, significant interplanetary effects are not likely. The variation of the Alfvenic critical radius in solar wind dwells is calculated, showing that the high-velocity stream originates from a significantly lower altitude than the ambient solar wind.

Contribution of strong discontinuities to the power spectrum of the solar wind.

PubMed

Borovsky, Joseph E

2010-09-10

Eight and a half years of magnetic field measurements (2(22) samples) from the ACE spacecraft in the solar wind at 1 A.U. are analyzed. Strong (large-rotation-angle) discontinuities in the solar wind are collected and measured. An artificial time series is created that preserves the timing and amplitudes of the discontinuities. The power spectral density of the discontinuity series is calculated and compared with the power spectral density of the solar-wind magnetic field. The strong discontinuities produce a power-law spectrum in the "inertial subrange" with a spectral index near the Kolmogorov -5/3 index. The discontinuity spectrum contains about half of the power of the full solar-wind magnetic field over this "inertial subrange." Warnings are issued about the significant contribution of discontinuities to the spectrum of the solar wind, complicating interpretation of spectral power and spectral indices.

Prompt Disappearance and Emergence of Radiation Belt Magnetosonic Waves Induced by Solar Wind Dynamic Pressure Variations

NASA Astrophysics Data System (ADS)

Liu, Nigang; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Wang, Shui

2018-01-01

Magnetosonic waves are highly oblique whistler mode emissions transferring energy from the ring current protons to the radiation belt electrons in the inner magnetosphere. Here we present the first report of prompt disappearance and emergence of magnetosonic waves induced by the solar wind dynamic pressure variations. The solar wind dynamic pressure reduction caused the magnetosphere expansion, adiabatically decelerated the ring current protons for the Bernstein mode instability, and produced the prompt disappearance of magnetosonic waves. On the contrary, because of the adiabatic acceleration of the ring current protons by the solar wind dynamic pressure enhancement, magnetosonic waves emerged suddenly. In the absence of impulsive injections of hot protons, magnetosonic waves were observable even only during the time period with the enhanced solar wind dynamic pressure. Our results demonstrate that the solar wind dynamic pressure is an essential parameter for modeling of magnetosonic waves and their effect on the radiation belt electrons.

Elsaesser variable analysis of fluctuations in the ion foreshock and undisturbed solar wind

NASA Technical Reports Server (NTRS)

Labelle, James; Treumann, Rudolf A.; Marsch, Eckart

1994-01-01

Magnetohydrodynamics (MHD) fluctuations in the solar wind have been investigated previously by use of Elsaesser variables. In this paper, we present a comparison of the spectra of Elsaesser variables in the undisturbed solar wind at 1 AU and in the ion foreshock in front of the Earth. Both observations take place under relatively strong solar wind flow speed conditions (approximately equal 600 km/s). In the undisturbed solar wind we find that outward propagating Alfven waves dominate, as reported by other observers. In the ion foreshock the situation is more complex, with neither outward nor inward propagation dominating over the entire range investigated (1-10 mHz). Measurements of the Poynting vectors associated with the fluctuations are consistent with the Elsaesser variable analysis. These results generally support interpretations of the Elsaesser variables which have been made based strictly on solar wind data and provide additional insight into the nature of the ion foreshock turbulence.

A comparison of empirical and experimental O7+, O8+, and O/H values, with applications to terrestrial solar wind charge exchange

NASA Astrophysics Data System (ADS)

Whittaker, Ian C.; Sembay, Steve

2016-07-01

Solar wind charge exchange occurs at Earth between the neutral planetary exosphere and highly charged ions of the solar wind. The main challenge in predicting the resultant photon flux in the X-ray energy bands is due to the interaction efficiency, known as the α value. This study produces experimental α values at the Earth, for oxygen emission in the range of 0.5-0.7 keV. Thirteen years of data from the Advanced Composition Explorer are examined, comparing O7+ and O8+ abundances, as well as O/H to other solar wind parameters allowing all parameters in the αO7,8+ calculation to be estimated based on solar wind velocity. Finally, a table is produced for a range of solar wind speeds giving average O7+ and O8+ abundances, O/H, and αO7,8+ values.

Costs of solar and wind power variability for reducing CO2 emissions.

PubMed

Lueken, Colleen; Cohen, Gilbert E; Apt, Jay

2012-09-04

We compare the power output from a year of electricity generation data from one solar thermal plant, two solar photovoltaic (PV) arrays, and twenty Electric Reliability Council of Texas (ERCOT) wind farms. The analysis shows that solar PV electricity generation is approximately one hundred times more variable at frequencies on the order of 10(-3) Hz than solar thermal electricity generation, and the variability of wind generation lies between that of solar PV and solar thermal. We calculate the cost of variability of the different solar power sources and wind by using the costs of ancillary services and the energy required to compensate for its variability and intermittency, and the cost of variability per unit of displaced CO(2) emissions. We show the costs of variability are highly dependent on both technology type and capacity factor. California emissions data were used to calculate the cost of variability per unit of displaced CO(2) emissions. Variability cost is greatest for solar PV generation at $8-11 per MWh. The cost of variability for solar thermal generation is $5 per MWh, while that of wind generation in ERCOT was found to be on average $4 per MWh. Variability adds ~$15/tonne CO(2) to the cost of abatement for solar thermal power, $25 for wind, and $33-$40 for PV.

Could Wind or Solar Energy Replace Diesel Generators for Aviation Ground Maintenance Operations?

DTIC Science & Technology

2013-04-17

power. Both of these systems depend on the sun to produce energy. Wind turbines depend on wind which results from the uneven heating of the earth...inefficient. In addition to these limitations, both systems are costly and their installation brings a number of challenges. For the wind turbines ...these challenges include: the obstruction created by the height of the turbines near airfields, the amount of land necessary for a 7 turbines wind farm

Acceleration of the Fast Solar Wind by Solitary Waves in Coronal Holes

NASA Technical Reports Server (NTRS)

Ofman, Leon

2001-01-01

The purpose of this investigation is to develop a new model for the acceleration of the fast solar wind by nonlinear. time-dependent multidimensional MHD simulations of waves in solar coronal holes. Preliminary computational studies indicate that nonlinear waves are generated in coronal holes by torsional Alfv\\'{e}n waves. These waves in addition to thermal conduction may contribute considerably to the accelerate the solar wind. Specific goals of this proposal are to investigate the generation of nonlinear solitary-like waves and their effect on solar wind acceleration by numerical 2.5D MHD simulation of coronal holes with a broad range of plasma and wave parameters; to study the effect of random disturbances at the base of a solar coronal hole on the fast solar wind acceleration with a more advanced 2.5D MHD model and to compare the results with the available observations; to extend the study to a full 3D MHD simulation of fast solar wind acceleration with a more realistic model of a coronal hole and solar boundary conditions. The ultimate goal of the three year study is to model the, fast solar wind in a coronal hole, based on realistic boundary conditions in a coronal hole near the Sun, and the coronal hole structure (i.e., density, temperature. and magnetic field geometry,) that will become available from the recently launched SOHO spacecraft.

Acceleration of the Fast Solar Wind by Solitary Waves in Coronal Holes

NASA Technical Reports Server (NTRS)

Ofman, Leon

2000-01-01

The purpose of this investigation is to develop a new model for the acceleration of the fast solar wind by nonlinear, time-dependent multidimensional MHD simulations of waves in solar coronal holes. Preliminary computational studies indicate that solitary-like waves are generated in coronal holes nonlinearly by torsional Alfven waves. These waves in addition to thermal conduction may contribute considerably to the accelerate the solar wind. Specific goals of this proposal are to investigate the generation of nonlinear solitary-like waves and their effect on solar wind acceleration by numerical 2.5D MHD simulation of coronal holes with a broad range of plasma and wave parameters; to study the effect of random disturbances at the base of a solar coronal hole on the fast solar wind acceleration with a more advanced 2.5D MHD model and to compare the results with the available observations; to extend the study to a full 3D MHD simulation of fast solar wind acceleration with a more realistic model of a coronal hole and solar boundary conditions. The ultimate goal of the three year study is to model the fast solar wind in a coronal hole, based on realistic boundary conditions in a coronal hole near the Sun, and the coronal hole structure (i.e., density, temperature, and magnetic field geometry) that will become available from the recently launched SOHO spacecraft.

Global solar wind variations over the last four centuries.

PubMed

Owens, M J; Lockwood, M; Riley, P

2017-01-31

The most recent "grand minimum" of solar activity, the Maunder minimum (MM, 1650-1710), is of great interest both for understanding the solar dynamo and providing insight into possible future heliospheric conditions. Here, we use nearly 30 years of output from a data-constrained magnetohydrodynamic model of the solar corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global solar wind variations over the last 400 years. Relative to the modern era, the MM shows a factor 2 reduction in near-Earth heliospheric magnetic field strength and solar wind speed, and up to a factor 4 increase in solar wind Mach number. Thus solar wind energy input into the Earth's magnetosphere was reduced, resulting in a more Jupiter-like system, in agreement with the dearth of auroral reports from the time. The global heliosphere was both smaller and more symmetric under MM conditions, which has implications for the interpretation of cosmogenic radionuclide data and resulting total solar irradiance estimates during grand minima.

The Distribution of Solar Wind Speeds During Solar Minimum: Calibration for Numerical Solar Wind Modeling Constraints on the Source of the Slow Solar Wind (Postprint)

DTIC Science & Technology

2012-03-05

subsonic corona below the critical point, resulting in an increased scale height and mass flux, while keeping the kinetic energy of the flow fairly...Approved for public release; distribution is unlimited. tubes with small expansion factors the heating occurs in the supersonic corona, where the energy ...goes into the kinetic energy of the solar wind, increasing the flow speed [Leer and Holzer, 1980; Pneuman, 1980]. Using this model and a sim- plified

26 CFR 1.23-2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... form of energy (such as oil or gas) other than solar, wind, or geothermal energy (or other forms of... from sunlight (solar radiation), such as fossil fuel or wood or heat in underground water, is not... components) are not included within the term “solar energy property”. For example, roof ponds that form part...

26 CFR 1.23-2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... form of energy (such as oil or gas) other than solar, wind, or geothermal energy (or other forms of... from sunlight (solar radiation), such as fossil fuel or wood or heat in underground water, is not... components) are not included within the term “solar energy property”. For example, roof ponds that form part...

26 CFR 1.23-2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... form of energy (such as oil or gas) other than solar, wind, or geothermal energy (or other forms of... from sunlight (solar radiation), such as fossil fuel or wood or heat in underground water, is not... components) are not included within the term “solar energy property”. For example, roof ponds that form part...

26 CFR 1.23-2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... form of energy (such as oil or gas) other than solar, wind, or geothermal energy (or other forms of... from sunlight (solar radiation), such as fossil fuel or wood or heat in underground water, is not... components) are not included within the term “solar energy property”. For example, roof ponds that form part...

26 CFR 1.23-2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... form of energy (such as oil or gas) other than solar, wind, or geothermal energy (or other forms of... from sunlight (solar radiation), such as fossil fuel or wood or heat in underground water, is not... components) are not included within the term “solar energy property”. For example, roof ponds that form part...

Inertial Range Turbulence of Fast and Slow Solar Wind at 0.72 AU and Solar Minimum

NASA Astrophysics Data System (ADS)

Teodorescu, Eliza; Echim, Marius; Munteanu, Costel; Zhang, Tielong; Bruno, Roberto; Kovacs, Peter

2015-05-01

We investigate Venus Express observations of magnetic field fluctuations performed systematically in the solar wind at 0.72 Astronomical Units (AU), between 2007 and 2009, during the deep minimum of solar cycle 24. The power spectral densities (PSDs) of the magnetic field components have been computed for time intervals that satisfy the data integrity criteria and have been grouped according to the type of wind, fast and slow, defined for speeds larger and smaller, respectively, than 450 km s-1. The PSDs show higher levels of power for the fast wind than for the slow. The spectral slopes estimated for all PSDs in the frequency range 0.005-0.1 Hz exhibit a normal distribution. The average value of the trace of the spectral matrix is -1.60 for fast solar wind and -1.65 for slow wind. Compared to the corresponding average slopes at 1 AU, the PSDs are shallower at 0.72 AU for slow wind conditions suggesting a steepening of the solar wind spectra between Venus and Earth. No significant time variation trend is observed for the spectral behavior of both the slow and fast wind.

76 FR 73783 - Residential, Business, and Wind and Solar Resource Leases on Indian Land

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-29

... Affairs 25 CFR Part 162 Residential, Business, and Wind and Solar Resource Leases on Indian Land; Proposed...-0001] RIN 1076-AE73 Residential, Business, and Wind and Solar Resource Leases on Indian Land AGENCY... leases, and solar resource development leases on Indian land, and would therefore remove the existing...

Solar wind temperature observations in the outer heliosphere

NASA Technical Reports Server (NTRS)

Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.

1992-01-01

The Pioneer 10, Pioneer 11, and Voyager 2 spacecraft are now at heliocentric distances of 50, 32 and 33 AU, and heliographic latitudes of 3.5 deg N, 17 deg N, and 0 deg N, respectively. Pioneer 11 and Voyager 2 are at similar celestial longitudes, while Pioneer l0 is on the opposite side of the sun. The baselines defined by these spacecraft make it possible to resolve radial, longitudinal, and latitudinal variations of solar wind parameters. The solar wind temperature decreases with increasing heliocentric distance out to a distance of 10-15 AU. At larger heliocentric distances, this gradient disappears. These high solar wind temperatures in the outer heliosphere have persisted for at least 10 years, which suggests that they are not a solar cycle effect. The solar wind temperature varied with heliographic latitude during the most recent solar minimum. The solar wind temperature at Pioneer 11 and Voyager 2 was higher than that seen at Pioneer 10 for an extended period of time, which suggests the existence of a large-scale variation of temperature with celestial longitude, but the contribution of transient phenomena is yet to be clarified.

Magnetosphere-Ionosphere-Thermosphere Response to Quasi-periodic Oscillations in Solar Wind Driving Conditions

NASA Astrophysics Data System (ADS)

Liu, J.; Wang, W.; Zhang, B.; Huang, C.

2017-12-01

Periodical oscillations with periods of several tens of minutes to several hours are commonly seen in the Alfven wave embedded in the solar wind. It is yet to be known how the solar wind oscillation frequency modulates the solar wind-magnetosphere-ionosphere coupled system. Utilizing the Coupled Magnetosphere-Ionosphere-Thermosphere Model (CMIT), we analyzed the magnetosphere-ionosphere-thermosphere system response to IMF Bz oscillation with periods of 10, 30, and 60 minutes from the perspective of energy budget and electrodynamic coupling processes. Our results indicate that solar wind energy coupling efficiency depends on IMF Bz oscillation frequency; energy coupling efficiency, represented by the ratio between globally integrated Joule heating and Epsilon function, is higher for lower frequency IMF Bz oscillation. Ionospheric Joule heating dissipation not only depends on the direct solar wind driven process but also is affected by the intrinsic nature of magnetosphere (i.e. loading-unloading process). In addition, ionosphere acts as a low-pass filter and tends to filter out very high-frequency solar wind oscillation (i.e. shorter than 10 minutes). Ionosphere vertical ion drift is most sensitive to IMF Bz oscillation compared to hmF2, and NmF2, while NmF2 is less sensitive. This can account for not synchronized NmF2 and hmF2 response to penetration electric fields in association with fast solar wind changes. This research highlights the critical role of IMF Bz oscillation frequency in constructing energy coupling function and understanding electrodynamic processes in the coupled solar wind-magnetosphere-ionosphere system.

Wind and Solar on the Power Grid: Myths and Misperceptions, Greening the Grid (Spanish Version)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Authors: Denholm, Paul; Cochran, Jaquelin; Brancucci Martinez-Anido, Carlo

This is the Spanish version of the 'Greening the Grid - Wind and Solar on the Power Grid: Myths and Misperceptions'. Wind and solar are inherently more variable and uncertain than the traditional dispatchable thermal and hydro generators that have historically provided a majority of grid-supplied electricity. The unique characteristics of variable renewable energy (VRE) resources have resulted in many misperceptions regarding their contribution to a low-cost and reliable power grid. Common areas of concern include: 1) The potential need for increased operating reserves, 2) The impact of variability and uncertainty on operating costs and pollutant emissions of thermal plants,more » and 3) The technical limits of VRE penetration rates to maintain grid stability and reliability. This fact sheet corrects misperceptions in these areas.« less

Pickup Protons: Comparisons using the Three-Dimensional MHD HHMS-PI model and Ulysses SWICS Measurements

NASA Technical Reports Server (NTRS)

Intriligator, Devrie S.; Detman, Thomas; Gloecker, George; Gloeckler, Christine; Dryer, Murray; Sun, Wei; Intriligator, James; Deehr, Charles

2012-01-01

We report the first comparisons of pickup proton simulation results with in situ measurements of pickup protons obtained by the SWICS instrument on Ulysses. Simulations were run using the three dimensional (3D) time-dependent Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI). HHMS-PI is an MHD solar wind model, expanded to include the basic physics of pickup protons from neutral hydrogen that drifts into the heliosphere from the local interstellar medium. We use the same model and input data developed by Detman et al. (2011) to now investigate the pickup protons. The simulated interval of 82 days in 2003 2004, includes both quiet solar wind (SW) and also the October November 2003 solar events (the Halloween 2003 solar storms). The HHMS-PI pickup proton simulations generally agree with the SWICS measurements and the HHMS-PI simulated solar wind generally agrees with SWOOPS (also on Ulysses) measurements. Many specific features in the observations are well represented by the model. We simulated twenty specific solar events associated with the Halloween 2003 storm. We give the specific values of the solar input parameters for the HHMS-PI simulations that provide the best combined agreement in the times of arrival of the solar-generated shocks at both ACE and Ulysses. We show graphical comparisons of simulated and observed parameters, and we give quantitative measures of the agreement of simulated with observed parameters. We suggest that some of the variations in the pickup proton density during the Halloween 2003 solar events may be attributed to depletion of the inflowing local interstellar medium (LISM) neutral hydrogen (H) caused by its increased conversion to pickup protons in the immediately preceding shock.

Physics of the inner heliosphere: Mechanisms, models and observational signatures

NASA Technical Reports Server (NTRS)

Withbroe, G. L.

1985-01-01

The physics of the solar wind acceleration phenomena (e.g. effect of transient momentum deposition on the temporal and spatial variation of the temperature, density and flow speed of the solar wind, formation of shocks, etc.) and the resultant effects on observational signatures, particularly spectroscopic signature are studied. Phenomena under study include: (1) wave motions, particularly spectroscopic signatures are studied. Phenomena under study include:(1) wave motions, particularly Alfven and fast mode waves, (2) the formation of standing shocks in the inner heliosphere as a result of momentum and/or heat addition to the wind and (3) coronal transient phenomena where momentum and/or heat are deposited in the corona to produce transient plasma heating and/or mass ejections. Also included are the theoretical investigation of spectroscopic plasma diagnostics for the inner heliosphere and the analysis of existing Skylab and other relevant data.

The goldstone energy project

NASA Technical Reports Server (NTRS)

Bartos, K. P.

1978-01-01

The Golstone Energy Project was established in 1974 to investigate ways in which the Goldstone Deep Space Complex in California could be made partly or completely energy-sufficient, especially through the use of solar- and wind-derived energy resources. Ways in which energy could be conserved at the Complex were also studied. Findings included data on both wind and solar energy. Obstacles to demonstrating energy self-sufficiency are: (1) operation and maintenance costs of solar energy systems are estimated to be much higher than conventional energy systems, (2) initial capital costs of present-day technology solar collectors are high and are compounded by low collector efficiency, and (3) no significant market force exists to create the necessary industry to reduce costs through mass production and broad open-market competition.

Statistical Behavior of Quasi-Steady Balanced Reconnection in Earth's Magnetosphere

NASA Astrophysics Data System (ADS)

Kissinger, Jennifer Eileen

Magnetic reconnection between Earth's magnetosphere and the solar wind results in several modes of response, including the impulsive substorm and the quasi-steady mode known as steady magnetospheric convection (SMC). SMC events are theorized to result from balancing the dayside and nightside reconnection rates. The reasons the magnetosphere responds with different modes are not fully known. This dissertation comprises statistical data analysis of the SMC mode to investigate the solar wind conditions and magnetospheric properties during these events. A comprehensive list of SMC events is selected from 1997-2011. In the first of three studies, an association between SMCs and solar wind stream interfaces (SI) is identified in the declining phase of Solar Cycle 23. SMC occurrence peaks 12-24 hours after an SI if the solar wind is geoeffective. The subset of SI-associated SMCs occurs during fast solar wind velocity, in contrast to previous results, but the driving electric field imposed on the magnetosphere (Ey) is the same for SI-associated and unassociated SMC events. Therefore the magnitude and steadiness of E y is the most important solar wind parameter for an SMC to occur. The second study shows that magnetotail convection is significantly different for SMC events, compared to quiet intervals and isolated substorms. Fast flows transporting enhanced magnetic flux are deflected toward the dawn and dusk flanks during SMC. Flow diversion is due to a broad high pressure region in the inner magnetosphere. The interval preceding SMC events is found to set up the magnetotail conditions that assist balanced reconnection. In particular inner magnetosphere pressure before SMCs is enhanced from substorm levels but not as high as SMC levels. The final study shows that nearly all SMCs are preceded by a substorm expansion. In rare cases when an SMC occurs without a preceding substorm, we hypothesize that the distant x-line is able to balance a weak solar wind driver. These results help explain how quasi-steady magnetospheric convection occurs. A southward turning of the solar wind and positive Ey leads to dayside reconnection and a substorm onset occurs. Plasma injections from the near-Earth nightside x-line increase the pressure in the inner magnetosphere. If positive Ey continues to drive dayside reconnection, the nightside x-line will stabilize to match it. Tail flux is diverted towards the flanks by pressure gradients and returns to the dayside. This convection pattern keeps the magnetosphere in its balanced reconnection mode.

A close-up of the sun. [solar probe mission planning conference

NASA Technical Reports Server (NTRS)

Neugebauer, M. (Editor); Davies, R. W. (Editor)

1978-01-01

NASA's long-range plan for the study of solar-terrestrial relations includes a Solar Probe Mission in which a spacecraft is put into an eccentric orbit with perihelion near 4 solar radii (0.02 AU). The scientific experiments which might be done with such a mission are discussed. Topics include the distribution of mass within the Sun, solar angular momentum, the fine structure of the solar surface and corona, the acceleration of the solar wind and energetic particles, and the evolution of interplanetary dust. The mission could also contribute to high-accuracy tests of general relativity and the search for cosmic gravitational radiation.

Heliophysics 2009 Roadmap and Global Change: Possibilities for Improved Understanding of the Connection

NASA Technical Reports Server (NTRS)

Spann, Jim

2010-01-01

Heliophysics is the science that includes all aspects of the research needed to understand the Sun and its effects on the Earth and the solar system. Six science targets: 1. Origins of Near-Earth Plasma - to understand the origin and transport of terrestrial plasma from its source to the magnetosphere and solar wind. 2. Solar Energetic Particle Acceleration and Transport - to understand how and where solar eruptions accelerate energetic particles that reach Earth. 3. Ion-Neutral Coupling in the Atmosphere - to understand how neutral winds control ionospheric variability. 4. Climate Impacts of Space Radiation - to understand our atmosphere s response to auroral, radiation belt, and solar energetic particles, and the associated effects on nitric oxide (NO) and ozone. 5. Dynamic Geospace Coupling - to understand how magnetospheric dynamics provides energy into the coupled ionosphere-magnetosphere system. 6. Heliospheric Magnetics - to understand the flow and dynamics of transient magnetic structures form the solar interior to Earth.

Magnetic Pumping as a Source of Particle Heating and Power-law Distributions in the Solar Wind

NASA Astrophysics Data System (ADS)

Lichko, E.; Egedal, J.; Daughton, W.; Kasper, J.

2017-12-01

Based on the rate of expansion of the solar wind, the plasma should cool rapidly as a function of distance to the Sun. Observations show this is not the case. In this work, a magnetic pumping model is developed as a possible explanation for the heating and the generation of power-law distribution functions observed in the solar wind plasma. Most previous studies in this area focus on the role that the dissipation of turbulent energy on microscopic kinetic scales plays in the overall heating of the plasma. However, with magnetic pumping, particles are energized by the largest-scale turbulent fluctuations, thus bypassing the energy cascade. In contrast to other models, we include the pressure anisotropy term, providing a channel for the large-scale fluctuations to heat the plasma directly. A complete set of coupled differential equations describing the evolution, and energization, of the distribution function are derived, as well as an approximate closed-form solution. Numerical simulations using the VPIC kinetic code are applied to verify the model’s analytical predictions. The results of the model for realistic solar wind scenario are computed, where thermal streaming of particles are important for generating a phase shift between the magnetic perturbations and the pressure anisotropy. In turn, averaged over a pump cycle, the phase shift permits mechanical work to be converted directly to heat in the plasma. The results of this scenario show that magnetic pumping may account for a significant portion of the solar wind energization.

Solar Wind Sputtering of Lunar Surface Materials: Role and Some Possible Implications of Potential Sputtering

NASA Technical Reports Server (NTRS)

Barghouty, A. F.; Adams, J. H., Jr.; Meyer, F.; Reinhold, c.

2010-01-01

Solar-wind induced sputtering of the lunar surface includes, in principle, both kinetic and potential sputtering. The role of the latter mechanism, however, in many focused studies has not been properly ascertained due partly to lack of data but can also be attributed to the assertion that the contribution of solar-wind heavy ions to the total sputtering is quite low due to their low number density compared to solar-wind protons. Limited laboratory measurements show marked enhancements in the sputter yields of slow-moving, highly-charged ions impacting oxides. Lunar surface sputtering yields are important as they affect, e.g., estimates of the compositional changes in the lunar surface, its erosion rate, as well as its contribution to the exosphere as well as estimates of hydrogen and water contents. Since the typical range of solar-wind ions at 1 keV/amu is comparable to the thickness of the amorphous rim found on lunar soil grains, i.e. few 10s nm, lunar simulant samples JSC-1A AGGL are specifically enhanced to have such rims in addition to the other known characteristics of the actual lunar soil particles. However, most, if not all laboratory studies of potential sputtering were carried out in single crystal targets, quite different from the rim s amorphous structure. The effect of this structural difference on the extent of potential sputtering has not, to our knowledge, been investigated to date.

Mini-Magnetospheres at the Moon in the Solar Wind and the Earth's Plasma Sheet

NASA Astrophysics Data System (ADS)

Harada, Y.; Futaana, Y.; Barabash, S. V.; Wieser, M.; Wurz, P.; Bhardwaj, A.; Asamura, K.; Saito, Y.; Yokota, S.; Tsunakawa, H.; Machida, S.

2014-12-01

Lunar mini-magnetospheres are formed as a consequence of solar-wind interaction with remanent crustal magnetization on the Moon. A variety of plasma and field perturbations have been observed in a vicinity of the lunar magnetic anomalies, including electron energization, ion reflection/deflection, magnetic field enhancements, electrostatic and electromagnetic wave activities, and low-altitude ion deceleration and electron acceleration. Recent Chandrayaan-1 observations of the backscattered energetic neutral atoms (ENAs) from the Moon in the solar wind revealed upward ENA flux depletion (and thus depletion of the proton flux impinging on the lunar surface) in association with strongly magnetized regions. These ENA observations demonstrate that the lunar surface is shielded from the solar wind protons by the crustal magnetic fields. On the other hand, when the Moon was located in the Earth's plasma sheet, no significant depletion of the backscattered ENA flux was observed above the large and strong magnetic anomaly. It suggests less effective magnetic shielding of the surface from the plasma sheet protons than from the solar wind protons. We conduct test-particle simulations showing that protons with a broad velocity distribution are more likely to reach a strongly magnetized surface than those with a beam-like velocity distribution. The ENA observations together with the simulation results suggest that the lunar crustal magnetic fields are no longer capable of standing off the ambient plasma when the Moon is immersed in the hot magnetospheric plasma.

Modeling Magnetospheric Sources

NASA Technical Reports Server (NTRS)

Walker, Raymond J.; Ashour-Abdalla, Maha; Ogino, Tatsuki; Peroomian, Vahe; Richard, Robert L.

2001-01-01

We have used global magnetohydrodynamic, simulations of the interaction between the solar wind and magnetosphere together with single particle trajectory calculations to investigate the sources of plasma entering the magnetosphere. In all of our calculations solar wind plasma primarily enters the magnetosphere when the field line on which it is convecting reconnects. When the interplanetary magnetic field has a northward component the reconnection is in the polar cusp region. In the simulations plasma in the low latitude boundary layer (LLBL) can be on either open or closed field lines. Open field lines occur when the high latitude reconnection occurs in only one cusp. In the MHD calculations the ionosphere does not contribute significantly to the LLBL for northward IMF. The particle trajectory calculations show that ions preferentially enter in the cusp region where they can be accelerated by non-adiabatic motion across the high latitude electric field. For southward IMF in the MHD simulations the plasma in the middle and inner magnetosphere comes from the inner (ionospheric) boundary of the simulation. Solar wind plasma on open field lines is confined to high latitudes and exits the tailward boundary of the simulation without reaching the plasma sheet. The LLBL is populated by both ionospheric and solar wind plasma. When the particle trajectories are included solar wind ions can enter the middle magnetosphere. We have used both the MHD simulations and the particle calculations to estimate source rates for the magnetosphere which are consistent with those inferred from observations.

Generation and evolution of anisotropic turbulence and related energy transfer in drifting proton-alpha plasmas

NASA Astrophysics Data System (ADS)

Maneva, Y. G.; Poedts, S.

2018-05-01

The power spectra of magnetic field fluctuations in the solar wind typically follow a power-law dependence with respect to the observed frequencies and wave-numbers. The background magnetic field often influences the plasma properties, setting a preferential direction for plasma heating and acceleration. At the same time the evolution of the solar-wind turbulence at the ion and electron scales is influenced by the plasma properties through local micro-instabilities and wave-particle interactions. The solar-wind-plasma temperature and the solar-wind turbulence at sub- and sup-ion scales simultaneously show anisotropic features, with different components and fluctuation power in parallel with and perpendicular to the orientation of the background magnetic field. The ratio between the power of the magnetic field fluctuations in parallel and perpendicular direction at the ion scales may vary with the heliospheric distance and depends on various parameters, including the local wave properties and nonthermal plasma features, such as temperature anisotropies and relative drift speeds. In this work we have performed two-and-a-half-dimensional hybrid simulations to study the generation and evolution of anisotropic turbulence in a drifting multi-ion species plasma. We investigate the evolution of the turbulent spectral slopes along and across the background magnetic field for the cases of initially isotropic and anisotropic turbulence. Finally, we show the effect of the various turbulent spectra for the local ion heating in the solar wind.

Tsallis non-extensive statistics and solar wind plasma complexity

NASA Astrophysics Data System (ADS)

Pavlos, G. P.; Iliopoulos, A. C.; Zastenker, G. N.; Zelenyi, L. M.; Karakatsanis, L. P.; Riazantseva, M. O.; Xenakis, M. N.; Pavlos, E. G.

2015-03-01

This article presents novel results revealing non-equilibrium phase transition processes in the solar wind plasma during a strong shock event, which took place on 26th September 2011. Solar wind plasma is a typical case of stochastic spatiotemporal distribution of physical state variables such as force fields (B → , E →) and matter fields (particle and current densities or bulk plasma distributions). This study shows clearly the non-extensive and non-Gaussian character of the solar wind plasma and the existence of multi-scale strong correlations from the microscopic to the macroscopic level. It also underlines the inefficiency of classical magneto-hydro-dynamic (MHD) or plasma statistical theories, based on the classical central limit theorem (CLT), to explain the complexity of the solar wind dynamics, since these theories include smooth and differentiable spatial-temporal functions (MHD theory) or Gaussian statistics (Boltzmann-Maxwell statistical mechanics). On the contrary, the results of this study indicate the presence of non-Gaussian non-extensive statistics with heavy tails probability distribution functions, which are related to the q-extension of CLT. Finally, the results of this study can be understood in the framework of modern theoretical concepts such as non-extensive statistical mechanics (Tsallis, 2009), fractal topology (Zelenyi and Milovanov, 2004), turbulence theory (Frisch, 1996), strange dynamics (Zaslavsky, 2002), percolation theory (Milovanov, 1997), anomalous diffusion theory and anomalous transport theory (Milovanov, 2001), fractional dynamics (Tarasov, 2013) and non-equilibrium phase transition theory (Chang, 1992).

MO and DA on the SWIE Instrument on the Wind Spacecraft

NASA Technical Reports Server (NTRS)

Lazarus, Alan J.

2002-01-01

The construction of the Faraday Cup portion of the SWIE instrument on the Wind spacecraft, participation in Mission Operations, and Data Analysis (MO and DA) of observations of the solar wind has been supported by a sequence of grants. This 'final' Report represents work done on Mission Operations and Data Analysis for the Faraday Cup portion of the SWE. The work reported here was supported under NASA Grant NAG5-7359 (OSP 6701100) from June 1998 to October 2001. It should be noted that this work is continuing under NASA Grant NAG-10915, and therefore this report is 'final' only in the sense that the Grant has changed its number; a future report will cover the entire period of work. We have two types of obligations under these contracts: (1) To provide and assure the validity of "Key Parameters" which describe the basic properties of the solar wind on a daily basis. We have provided our 92 second observations daily via plots and parameters available from our Web site: http://web.mit.edu/space/www/wind/wind.html (2). To carry out scientific studies based on our observations. To document the extent of our research, we are including below a list of publications and presentations related to this project. The observations from Wind have made a major contribution to the study of the solar wind, and have every indication of continuing to do so.

A broad look at solar physics adapted from the solar physics study of August 1975

NASA Technical Reports Server (NTRS)

Parker, E.; Timothy, A.; Beckers, J.; Hundhausen, A.; Kundu, M. R.; Leith, C. E.; Lin, R.; Linsky, J.; Macdonald, F. B.; Noyes, R.

1979-01-01

The current status of our knowledge of the basic mechanisms involved in fundamental solar phenomena is reviewed. These include mechanisms responsible for heating the corona, the generation of the solar wind, the particle acceleration in flares, and the dissipation of magnetic energy in field reversal regions, known as current sheets. The discussion covers solar flares and high-energy phenomena, solar active regions; solar interior, convection, and activity; the structure and energetics of the quiet solar atmosphere; the structure of the corona; the solar composition; and solar terrestrial interactions. It also covers a program of solar research, including the special observational requirements for spectral and angular resolution, sensitivity, time resolution, and duration of the techniques employed.

A study of the relationship between micropulsations and solar wind properties

NASA Technical Reports Server (NTRS)

Yedidia, B. A.; Lazarus, A. J.; Vellante, M.; Villante, U.

1991-01-01

A year-long comparison between daily averages of solar wind parameters obtained from the MIT experiment on IMP-8 and micropulsation measurements made by the Universita dell'Aquila has shown a correlation between solar wind speed and micropulsation power with peaks of the correlation coefficient greater than 0.8 in the period range from 20 to 40 s. Different behavior observed for different period bands suggests that the shorter period activity tends to precede the highest values of the solar wind speed while the longer period activity tends to persist for longer intervals within high velocity solar wind streams. A comparison with simultaneous interplanetary magnetic field measurements supports the upstream origin of the observed ground pulsations.

Long-term changes in solar wind elemental and isotopic ratios - A comparison of two lunar ilmenites of different antiquities

NASA Technical Reports Server (NTRS)

Becker, Richard H.; Pepin, Robert O.

1989-01-01

The solar wind components in two lunar ilmenites are examined. The noble gas and nitrogen elemental and isotopic abundances of lunar regolith breccia sample 79035, assumed to have been exposed to solar winds more than 2 Ga ago, are analyzed using stepwise oxidation and pyrolysis. This sample is compared with the data of Frick et al. (1988) for soil sample 71501, recently exposed to solar winds. It is observed that the two elements differ in terms of xenon abundance, helium and neon isotopic rates, and He/Ar elemental ratios. It is concluded that there have been isotopic and elemental abundance changes in solar wind composition over time.

A Geospatial Database for Wind and Solar Energy Applications: The Kingdom of Bahrain Study Case

NASA Astrophysics Data System (ADS)

Al-Joburi, Khalil; Dahman, Nidal

2017-11-01

This research is aimed at designing, implementing, and testing a geospatial database for wind and solar energy applications in the Kingdom of Bahrain. All decision making needed to determine economic feasibility and establish site location for wind turbines or solar panels depends primarily on geospatial feature theme information and non-spatial (attribute) data for wind, solar, rainfall, temperature and weather characteristics of a particular region. Spatial data includes, but is not limited to, digital elevation, slopes, land use, zonings, parks, population density, road utility maps, and other related information. Digital elevations for over 450,000 spot at 50 m spatial horizontal resolution plus field surveying and GPS (at selected locations) was obtained from the Surveying and Land Registration Bureau (SLRB). Road, utilities, and population density are obtained from the Central Information Organization (CIO). Land use zoning, recreational parks, and other data are obtained from the Ministry of Municipalities and Agricultural Affairs. Wind, solar, humidity, rainfall, and temperature data are obtained from the Ministry of Transportation, Civil Aviation Section. LandSat Satellite and others images are obtained from NASA and online sources respectively. The collected geospatial data was geo-referenced to Ain el-Abd UTM Zone 39 North. 3D Digital Elevation Model (DEM)-50 m spatial resolutions was created using SLRB spot elevations. Slope and aspect maps were generate based on the DEM. Supervised image classification to identify open spaces was performed utilizing satellite images. Other geospatial data was converted to raster format with the same cell resolution. Non-spatial data are entered as an attribute to spatial features. To eliminate ambiguous solution, multi-criteria GIS model is developed based on, vector (discrete point, line, and polygon representations) as well as raster model (continuous representation). The model was tested at the Al-Areen proposed project, a relatively small area (15 km2). Optimum site spatial location for the location of wind turbines and solar panels was determined and initial results indicates that the combination of wind and solar energy would be sufficient for the project to meet the energy demand at the present per capita consummation rate..

Spectral analysis of the solar wind turbulence in the vicinity of Venus

NASA Astrophysics Data System (ADS)

Teodorescu, Eliza; Echim, Marius; Munteanu, Costel; Voitcu, Gabriel; Zhang, Tielong; Barabash, Stanislav; Budnik, Elena; Fedorov, Andrei

2014-05-01

In this study we analyze magnetic field data provided by Venus Express (VEX) between 2007 and 2008. During each of the probe's eccentric polar orbit around Venus, VEX performs plasma and magnetic field measurements in the environment around the planet both in Venus induced magnetosphere and in the solar wind at several tens of thousands of kilometers away from the magnetosphere. This latter data set has a unique scientific value as it provides observations of magnetic turbulence in the solar wind around 0.72 AU, in the vicinity of Venus. We discuss a semi-automated method to select solar wind magnetic field data at 1 Hz from Venus Express Magnetometer (MAG) data by using plasma data from the Analyser of Space Plasma and Energetic Atoms (ASPERA). The time intervals when VEX is in the solar wind are automatically determined for 2007 and 2008. We apply a Fourier transform on the selected data and calculate the power spectral densities (PSD) of the turbulent magnetic field through Welch's algorithm. We compute the PSD of the three components of the magnetic field for the time intervals when both MAG and ASPERA were operating in the solar wind, for each VEX orbit between 1st of January 2007 and 31st of December 2008. The data base includes a number of 374 individual spectra. We discuss the spectral properties of turbulence and illustrate similarities between fast and slow wind during the minimum phase of the solar cycle for each of VEX's orbit which satisfies the selection criteria for a period of two years. Research supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 313038/STORM, and a grant of the Romanian Ministry of National Education, CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0418. Data analysis was done with the AMDA science analysis system provided by the Centre de Données de la Physique des Plasmas (IRAP, Université Paul Sabatier, Toulouse) supported by CNRS and CNES.

The Solar Wind Depletion (SWD) event of 26 April 1999: Triggering of an auroral pseudobreakup event

NASA Technical Reports Server (NTRS)

Zhou, X.; Tsurutani, B.; Gonzalez, W.

2000-01-01

The interplanetary solar wind depletion (SWD) event of 26 April 1999 and its magnetospheric consequences are examined. The SWD event is characterized by a solar wind density decrease from [similar to] 3.0 to 0.7 cm(sup -3) leading to a solar wind ram pressure decrease from [similar to] 2.0 to 0.2 nPa. This SWD onset is followed by a dipolarization of nightside magnetospheric fields.

Solar Wind Earth Exchange Project (SWEEP)

DTIC Science & Technology

2016-10-28

AFRL-AFOSR-UK-TR-2016-0035 Solar Wind Earth Exchange Project 140200 Steven Sembay UNIVERSITY OF LEICESTER Final Report 10/28/2016 DISTRIBUTION A...To) 01 Sep 2014 to 31 Aug 2016 4. TITLE AND SUBTITLE Solar Wind Earth Exchange Project (SWEEP) 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-14-1...SUPPLEMENTARY NOTES 14. ABSTRACT The grant received from AFRL/AOFSR/EOARD funded the Solar Wind Earth Exchange Project (SWEEP) at Leicester University. The goal

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.

A Study of the Structure of the Source Region of the Solar Wind in Support of a Solar Probe Mission

NASA Technical Reports Server (NTRS)

Habbal, Shadia R.; Forman, M. A. (Technical Monitor)

2001-01-01

Despite the richness of the information about the physical properties and the structure of the solar wind provided by the Ulysses and SOHO (Solar and Heliospheric Observatory) observations, fundamental questions regarding the nature of the coronal heating mechanisms, their source, and the manifestations of the fast and slow solar wind, still remain unanswered. The last unexplored frontier to establish the connection between the structure and dynamics of the solar atmosphere, its extension into interplanetary space, and the mechanisms responsible for the evolution of the solar wind, is the corona between 1 and 30 R(sub s). A Solar Probe mission offers an unprecedented opportunity to explore this frontier. Its uniqueness stems from its trajectory in a plane perpendicular to the ecliptic which reaches within 9 R(sub s) of the solar surface over the poles and 3 - 9 R(sub s) at the equator. With a complement of simultaneous in situ and remote sensing observations, this mission is destined to detect remnants and signatures of the processes which heat the corona and accelerate the solar wind. In support of this mission, we fulfilled the following two long-term projects: (1) Study of the evolution of waves and turbulence in the solar wind (2) Exploration of signatures of physical processes and structures in the corona. A summary of the tasks achieved in support of these projects are given below. In addition, funds were provided to support the Solar Wind 9 International Conference which was held in October 1998. A brief report on the conference is also described in what follows.

The International Cometary Explorer (ICE) mission to Comets Giacobini-Zinner and Halley

NASA Technical Reports Server (NTRS)

Brandt, J. C.

1986-01-01

Use of the ISEE-3 satellite (renamed ICE) to study the interaction between the solar wind and a cometary atmosphere by passing through the plasma tail by intercepting Comet Giacobini-Zinner on 11 September 1985 is described. Details of the targeting strategy are discussed. Additional scientific objectives following the tail intercept of Comet Giacobini-Zinner include the support of Comet Halley studies through the measurement of solar-wind conditions upstream of P/Halley in October 1985 and March 1986.

Using Photovoltaic (PV) Cells on Enduring DoD Installations in the Middle East: A Feasibility Study

DTIC Science & Technology

2013-06-01

geothermal , and biomass). In FY 2009, 3.6 percent of the DoD’s electrical consumption came from renewable electricity sources, exceeding the EP Act 2005...defined as electrical energy generated from solar, wind, biomass, landfill gas, ocean (including tidal, wave, current, and thermal), geothermal ...involving solar, wind, geothermal and biomass energy. The U.S. Navy accounts for 60 percent of DoD’s renewable energy projects—some 250 in total. The 14

Solar power. [comparison of costs to wind, nuclear, coal, oil and gas

NASA Technical Reports Server (NTRS)

Walton, A. L.; Hall, Darwin C.

1990-01-01

This paper describes categories of solar technologies and identifies those that are economic. It compares the private costs of power from solar, wind, nuclear, coal, oil, and gas generators. In the southern United States, the private costs of building and generating electricity from new solar and wind power plants are less than the private cost of electricity from a new nuclear power plant. Solar power is more valuable than nuclear power since all solar power is available during peak and midpeak periods. Half of the power from nuclear generators is off-peak power and therefore is less valuable. Reliability is important in determining the value of wind and nuclear power. Damage from air pollution, when factored into the cost of power from fossil fuels, alters the cost comparison in favor of solar and wind power. Some policies are more effective at encouraging alternative energy technologies that pollute less and improve national security.

Solar Wind Acceleration: Modeling Effects of Turbulent Heating in Open Flux Tubes

NASA Astrophysics Data System (ADS)

Woolsey, Lauren N.; Cranmer, Steven R.

2014-06-01

We present two self-consistent coronal heating models that determine the properties of the solar wind generated and accelerated in magnetic field geometries that are open to the heliosphere. These models require only the radial magnetic field profile as input. The first code, ZEPHYR (Cranmer et al. 2007) is a 1D MHD code that includes the effects of turbulent heating created by counter-propagating Alfven waves rather than relying on empirical heating functions. We present the analysis of a large grid of modeled flux tubes (> 400) and the resulting solar wind properties. From the models and results, we recreate the observed anti-correlation between wind speed at 1 AU and the so-called expansion factor, a parameterization of the magnetic field profile. We also find that our models follow the same observationally-derived relation between temperature at 1 AU and wind speed at 1 AU. We continue our analysis with a newly-developed code written in Python called TEMPEST (The Efficient Modified-Parker-Equation-Solving Tool) that runs an order of magnitude faster than ZEPHYR due to a set of simplifying relations between the input magnetic field profile and the temperature and wave reflection coefficient profiles. We present these simplifying relations as a useful result in themselves as well as the anti-correlation between wind speed and expansion factor also found with TEMPEST. Due to the nature of the algorithm TEMPEST utilizes to find solar wind solutions, we can effectively separate the two primary ways in which Alfven waves contribute to solar wind acceleration: 1) heating the surrounding gas through a turbulent cascade and 2) providing a separate source of wave pressure. We intend to make TEMPEST easily available to the public and suggest that TEMPEST can be used as a valuable tool in the forecasting of space weather, either as a stand-alone code or within an existing modeling framework.

Performance of an off-grid solar home in northwestern Vermont

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rawlings, L.K.

1997-12-31

In 1995 an off-grid integrated solar home was built in Middlesex, VT for Peter Clark and Gloria DeSousa. This home was included as a pilot home in the US DOE PV:BONUS program to develop factory-built integrated solar homes. The home incorporates a 1.44 KW PV system, 0.6 KW of wind turbine capacity, and very high-efficiency electrical loads. The home also features passive solar design, high-efficiency heating systems, and a greenhouse-based septic treatment system. The performance of the PV system and the wind system, and the total power usage of the household, are measured and recorded by a data acquisition system.more » The home`s electrical loads have operated very efficiently, using on average about one tenth the power used by the average American residence. The PV system has operated reliably and efficiently, providing about 97% of the power needs of the home. The wind turbines have operated efficiently, but the wind regime at the site has not been sufficient to generate more than 1% of the total power needs. The other 2% has been provided by a gasoline backup generator.« less

Magnetic pumping of the solar wind

NASA Astrophysics Data System (ADS)

Egedal, Jan; Lichko, Emily; Daughton, William

2015-11-01

The transport of matter and radiation in the solar wind and terrestrial magnetosphere is a complicated problem involving competing processes of charged particles interacting with electric and magnetic fields. Given the rapid expansion of the solar wind, it would be expected that superthermal electrons originating in the corona would cool rapidly as a function of distance to the Sun. However, this is not observed, and various models have been proposed as candidates for heating the solar wind. In the compressional pumping mechanism explored by Fisk and Gloeckler particles are accelerated by random compressions by the interplanetary wave turbulence. This theory explores diffusion due to spatial non-uniformities and provides a mechanism for redistributing particle. For investigation of a related but different heating mechanism, magnetic pumping, in our work we include diffusion of anisotropic features that develops in velocity space. The mechanism allows energy to be transferred to the particles directly from the turbulence. Guided by kinetic simulations a theory is derived for magnetic pumping. At the heart of this work is a generalization of the Parker Equation to capture the role of the pressure anisotropy during the pumping process. Supported by NASA grant NNX15AJ73G.

Laboratory Measurements of Solar-Wind/Comet X-Ray Emission and Charge Exchange Cross Sections

NASA Technical Reports Server (NTRS)

Chutjian, A.; Cadez, I.; Greenwood, J. B.; Mawhorter, R. J.; Smith, S. J.; Lozano, J.

2002-01-01

The detection of X-rays from comets such as Hyakutake, Hale-Bopp, d Arrest, and Linear as they approach the Sun has been unexpected and exciting. This phenomenon, moreover, should be quite general, occurring wherever a fast solar or stellar wind interacts with neutrals in a comet, a planetary atmosphere, or a circumstellar cloud. The process is, O(+8) + H2O --> O(+7*) + H2O(+), where the excited O(+7*) ions are the source of the X-ray emissions. Detailed modeling has been carried out of X-ray emissions in charge-transfer collisions of heavy solar-wind Highly Charged Ions (HCIs) and interstellar/interplanetary neutral clouds. In the interplanetary medium the solar wind ions, including protons, can charge exchange with interstellar H and He. This can give rise to a soft X-ray background that could be correlated with the long-term enhancements seen in the low-energy X-ray spectrum of ROSAT. Approximately 40% of the soft X-ray background detected by Exosat, ROSAT, Chandra, etc. is due to Charge Exchange (CXE): our whole heliosphere is glowing in the soft X-ray due to CXE.

Ion acceleration by multiple reflections at Martian bow shock

NASA Astrophysics Data System (ADS)

Yamauchi, M.; Futaana, Y.; Fedorov, A.; Frahm, R. A.; Dubinin, E.; Lundin, R.; Sauvaud, J.-A.; Winningham, J. D.; Barabash, S.; Holmström, M.

2012-02-01

The ion mass analyzer (IMA) on board Mars Express revealed bundled structures of ions in the energy domain within a distance of a proton gyroradius from the Martian bow shock. Seven prominent traversals during 2005 were examined when the energy-bunched structure was observed together with pick-up ions of exospheric origin, the latter of which is used to determine the local magnetic field orientation from its circular trajectory in velocity space. These seven traversals include different bow shock configurations: (a) quasi-perpendicular shock with its specular direction of the solar wind more perpendicular to the magnetic field (QT), (b) quasi-perpendicular shock with its specular reflection direction of the solar wind more along the magnetic field (FS), and (c) quasi-parallel (QL) shock. In all seven cases, the velocity components of the energy-bunched structure are consistent with multiple specular reflections of the solar wind at the bow shock up to at least two reflections. The accelerated solar wind ions after two specular reflections have large parallel components with respect to the magnetic field for both QL cases whereas the field-aligned speed is much smaller than the perpendicular speed for all QT cases.

Particle injection and acceleration at earth's bow shock - Comparison of upstream and downstream events

NASA Technical Reports Server (NTRS)

Ellison, Donald C.; Moebius, Eberhard; Paschmann, Goetz

1990-01-01

The injection and acceleration of thermal solar wind ions at the quasi-parallel earth's bow shock during radial interplanetary magnetic field conditions is investigated. Active Magnetospheric Particle Tracer Explorers/Ion Release Module satellite observations of complete proton spectra, and of heavy ion spectra above 10 keV/Q, made on September 12, 1984 near the nose of the shock, are presented and compared to the predictions of a Monte Carlo shock simulation which includes diffusive shock acceleration. It is found that the spectral observations are in good agreement with the predictions of the simulation when it is assumed that all accelerated ions originate in the solar wind and are injected into the acceleration mechanism by thermal leakage from the downstream plasma. The efficiency, which is determined directly from the downstream observations, is high, with at least 15 percent of the solar wind energy flux going into accelerated particles. The comparisons allow constraints to be placed on the rigidity dependence of the scattering mean free path and suggest that the upstream solar wind must be slowed substantially by backstreaming accelerated ions prior to undergoing a sharp transition in the viscous subshock.

GPP Webinar: Market Outlook and Innovations in Wind and Solar Power

EPA Pesticide Factsheets

Green Power Partnership webinar reviewing the state of the renewable energy industry as a whole, with a focus on wind and solar power and exploring recent marketplace innovations in wind and solar power and renewable energy purchases.

Generation of Kappa Distributions in Solar Wind at 1 au

NASA Astrophysics Data System (ADS)

Livadiotis, G.; Desai, M. I.; Wilson, L. B., III

2018-02-01

We examine the generation of kappa distributions in the solar wind plasma near 1 au. Several mechanisms are mentioned in the literature, each characterized by a specific relationship between the solar wind plasma features, the interplanetary magnetic field (IMF), and the kappa index—the parameter that governs the kappa distributions. This relationship serves as a signature condition that helps the identification of the mechanism in the plasma. In general, a mechanism that generates kappa distributions involves a single or a series of stochastic or physical processes that induces local correlations among particles. We identify three fundamental solar wind plasma conditions that can generate kappa distributions, noted as (i) Debye shielding, (ii) frozen IMF, and (iii) temperature fluctuations, each one prevailing in different scales of solar wind plasma and magnetic field properties. Moreover, our findings show that the kappa distributions, and thus, their generating mechanisms, vary significantly with solar wind features: (i) the kappa index has different dependence on the solar wind speed for slow and fast modes, i.e., slow wind is characterized by a quasi-constant kappa index, κ ≈ 4.3 ± 0.7, while fast wind exhibits kappa indices that increase with bulk speed; (ii) the dispersion of magnetosonic waves is more effective for lower kappa indices (i.e., further from thermal equilibrium); and (iii) the kappa and polytropic indices are positively correlated, as it was anticipated by the theory.

Stationarity of extreme bursts in the solar wind

NASA Astrophysics Data System (ADS)

Moloney, N. R.; Davidsen, J.

2014-05-01

Recent results have suggested that the statistics of bursts in the solar wind vary with solar cycle. Here, we show that this variation is basically absent if one considers extreme bursts. These are defined as threshold-exceeding events over the range of high thresholds for which their number decays as a power law. In particular, we find that the distribution of duration times and energies of extreme bursts in the solar wind ɛ parameter and similar observables are independent of the solar cycle and in this sense stationary, and show robust asymptotic power laws with exponents that are independent of the specific threshold. This is consistent with what has been observed for solar flares and, thus, provides evidence in favor of a link between solar flares and extreme bursts in the solar wind.

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.

Prediction of solar energetic particle event histories using real-time particle and solar wind measurements

NASA Technical Reports Server (NTRS)

Roelof, E. C.; Gold, R. E.

1978-01-01

The comparatively well-ordered magnetic structure in the solar corona during the decline of Solar Cycle 20 revealed a characteristic dependence of solar energetic particle injection upon heliographic longitude. When analyzed using solar wind mapping of the large scale interplanetary magnetic field line connection from the corona to the Earth, particle fluxes display an approximately exponential dependence on heliographic longitude. Since variations in the solar wind velocity (and hence the coronal connection longitude) can severely distort the simple coronal injection profile, the use of real-time solar wind velocity measurements can be of great aid in predicting the decay of solar particle events. Although such exponential injection profiles are commonplace during 1973-1975, they have also been identified earlier in Solar Cycle 20, and hence this structure may be present during the rise and maximum of the cycle, but somewhat obscured by greater temporal variations in particle injection.

Composition of the Solar Wind

NASA Technical Reports Server (NTRS)

Suess, S. T.

2007-01-01

The solar wind reflects the composition of the Sun and physical processes in the corona. Analysis produces information on how the solar system was formed and on physical processes in the corona. The analysis can also produce information on the local interstellar medium, galactic evolution, comets in the solar wind, dust in the heliosphere, and matter escaping from planets.

A Global Look at Future Trends in the Renewable Energy Resource

NASA Astrophysics Data System (ADS)

Chen, S.; Freedman, J. M.; Kirk-Davidoff, D. B.; Brower, M.

2017-12-01

With the aggressive deployment of utility-scale and distributed generation of wind and solar energy systems, an accurate estimate of the uncertainty associated with future resource trends and plant performance is crucial in maintaining financial integrity in the renewable energy markets. With continuing concerns regarding climate change, the move towards energy resiliency, and the cost-competitiveness of renewables, a rapidly expanding fleet of utility-scale wind and solar power facilities and distributed generation of both resources is now being incorporated into the electric distribution grid. Although solar and wind account for about 3% of global power production, renewable energy is now and will continue to be the world's fastest-growing energy source. With deeper penetration of renewables, confidence in future power production output on a spectrum of temporal and spatial scales is crucial to grid stability for long-term planning and achieving national and international targets in the reduction of greenhouse gas emissions. Here, we use output from a diverse subset of Earth System Models (Climate Model Inter-comparison Project-Phase 5 members) to produce projected trends and uncertainties in regional and global seasonal and inter-annual wind and solar power production and respective capacity factors through the end of the 21st century. Our trends and uncertainty analysis focuses on the Representative Concentration Pathways (RCP) 4.5 and RCP 8.5 scenarios. For wind and solar energy production estimates, we extract surface layer wind (extrapolated to hub height), irradiance, cloud fraction, and temperature (air temperature affects density [hence wind power production] and the efficiency of photovoltaic [PV] systems), output from the CMIP5 ensemble mean fields for the period 2020 - 2099 and an historical baseline for POR of 1986 - 2005 (compared with long-term observations and the ERA-Interim Reanalysis). Results include representative statistics such as the standard deviation (as determined from the slopes of the trend lines for individual CMIP5 members), means, medians (e.g. P50 values) and percent change, trends analysis on time series for each variable, and creation of global maps of trends (% change per year) and changes in capacity factors for both estimated solar and wind power production.

Soho Ultraviolet Coronograph Spectrometer (UVCS) Mission Operations and Data Analysis

NASA Technical Reports Server (NTRS)

Kohl, John L.; Gurman, Joseph (Technical Monitor)

2002-01-01

The scientific goal of UVCS is to obtain detailed empirical descriptions of the extended solar corona as it evolves over the solar cycle and to use these descriptions to identify and understand the physical processes responsible for coronal heating, solar wind acceleration, coronal mass ejections (CMEs), and the phenomena that establish the plasma properties of the solar wind as measured by 'in situ' solar wind instruments. This report covers the period from 01 December 2000 to 31 January 2002. During that time, UVCS observations have consisted of three types: (1) standard synoptic observations comprising, primarily, the H I Ly(alpha) line profile and the O VI 103.2 and 103.7 nm intensity over a range of heights from 1.5 to about 3.0 solar radii and covering 360 degrees about the sun; (2) sit and stare watches for CMEs; and (3) special observations designed by the UVCS Lead Observer of the Week for a specific scientific purpose. The special observations are often coordinated with those of other space-based and ground-based instruments and they often are part of SOHO joint observation programs and campaigns. Lead observers have included UVCS Co-Investigators, scientists from the solar physics community and several graduate and undergraduate level students.

Impacts of wind stilling on solar radiation variability in China

PubMed Central

Lin, Changgui; Yang, Kun; Huang, Jianping; Tang, Wenjun; Qin, Jun; Niu, Xiaolei; Chen, Yingying; Chen, Deliang; Lu, Ning; Fu, Rong

2015-01-01

Solar dimming and wind stilling (slowdown) are two outstanding climate changes occurred in China over the last four decades. The wind stilling may have suppressed the dispersion of aerosols and amplified the impact of aerosol emission on solar dimming. However, there is a lack of long-term aerosol monitoring and associated study in China to confirm this hypothesis. Here, long-term meteorological data at weather stations combined with short-term aerosol data were used to assess this hypothesis. It was found that surface solar radiation (SSR) decreased considerably with wind stilling in heavily polluted regions at a daily scale, indicating that wind stilling can considerably amplify the aerosol extinction effect on SSR. A threshold value of 3.5 m/s for wind speed is required to effectively reduce aerosols concentration. From this SSR dependence on wind speed, we further derived proxies to quantify aerosol emission and wind stilling amplification effects on SSR variations at a decadal scale. The results show that aerosol emission accounted for approximately 20% of the typical solar dimming in China, which was amplified by approximately 20% by wind stilling. PMID:26463748

Probability Density Functions of the Solar Wind Driver of the Magnetopshere-Ionosphere System

NASA Astrophysics Data System (ADS)

Horton, W.; Mays, M. L.

2007-12-01

The solar-wind driven magnetosphere-ionosphere system is a complex dynamical system in that it exhibits (1) sensitivity to initial conditions; (2) multiple space-time scales; (3) bifurcation sequences with hysteresis in transitions between attractors; and (4) noncompositionality. This system is modeled by WINDMI--a network of eight coupled ordinary differential equations which describe the transfer of power from the solar wind through the geomagnetic tail, the ionosphere, and ring current in the system. The model captures both storm activity from the plasma ring current energy, which yields a model Dst index result, and substorm activity from the region 1 field aligned current, yielding model AL and AU results. The input to the model is the solar wind driving voltage calculated from ACE solar wind parameter data, which has a regular coherent component and broad-band turbulent component. Cross correlation functions of the input-output data time series are computed and the conditional probability density function for the occurrence of substorms given earlier IMF conditions are derived. The model shows a high probability of substorms for solar activity that contains a coherent, rotating IMF with magnetic cloud features. For a theoretical model of the imprint of solar convection on the solar wind we have used the Lorenz attractor (Horton et al., PoP, 1999, doi:10.10631.873683) as a solar wind driver. The work is supported by NSF grant ATM-0638480.

Solar wind speed and He I (1083 nm) absorption line intensity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hakamada, Kazuyuki; Kojima, Masayoshi; Kakinuma, Takakiyo

1991-04-01

Since the pattern of the solar wind was relatively steady during Carrington rotations 1,748 through 1,752 in 1984, an average distribution of the solar windspeed on a so-called source surface can be constructed by superposed epoch analysis of the wind values estimated by the interplanetary scintillation observations. The average distribution of the solar wind speed is then projected onto the photosphere along magnetic field lines computed by a so-called potential model with the line-of-sight components of the photospheric magnetic fields. The solar wind speeds projected onto the photosphere are compared with the intensities of the He I (1,083 nm) absorptionmore » line at the corresponding locations in the chromosphere. The authors found that there is a linear relation between the speeds and the intensities. Since the intensity of the He I (1,083 nm) absorption line is coupled with the temperature of the corona, this relation suggests that some physical mechanism in or above the photosphere accelerates coronal plasmas to the solar wind speed in regions where the temperature is low. Further, it is suggested that the efficiency of the solar wind acceleration decreases as the coronal temperature increases.« less

Identification of Interplanetary Coronal Mass Ejections at 1 AU Using Multiple Solar Wind Plasma Composition Anomalies

NASA Technical Reports Server (NTRS)

Richardson, I. G.; Cane, H. V.

2004-01-01

We investigate the use of multiple simultaneous solar wind plasma compositional anomalies, relative to the composition of the ambient solar wind, for identifying interplanetary coronal mass ejection (ICME) plasma. We first summarize the characteristics of several solar wind plasma composition signatures (O(+7)/O(+6), Mg/O, Ne/O, Fe charge states, He/p) observed by the ACE and WIND spacecraft within the ICMEs during 1996 - 2002 identsed by Cane and Richardson. We then develop a set of simple criteria that may be used to identify such compositional anomalies, and hence potential ICMEs. To distinguish these anomalies from the normal variations seen in ambient solar wind composition, which depend on the wind speed, we compare observed compositional signatures with those 'expected' in ambient solar wind with the same solar wind speed. This method identifies anomalies more effectively than the use of fixed thresholds. The occurrence rates of individual composition anomalies within ICMEs range from approx. 70% for enhanced iron and oxygen charge states to approx. 30% for enhanced He/p (> 0.06) and Ne/O, and are generally higher in magnetic clouds than other ICMEs. Intervals of multiple anomalies are usually associated with ICMEs, and provide a basis for the identification of the majority of ICMEs. We estimate that Cane and Richardson, who did not refer to composition data, probably identitied approx. 90% of the ICMEs present. However, around 10% of their ICMEs have weak compositional anomalies, suggesting that the presence of such signatures does not provide a necessary requirement for an ICME. We note a remarkably similar correlation between the Mg/O and O(7)/O(6) ratios in hourly-averaged data both within ICMEs and the ambient solar wind. This 'universal' relationship suggests that a similar process (such as minor ion heating by waves inside coronal magnetic field loops) produces the first-ionization potential bias and ion freezing-in temperatures in the source regions of both ICMEs and the ambient solar wind.

25 CFR 162.010 - How do I obtain a lease?

Code of Federal Regulations, 2014 CFR

2014-04-01

... subpart E for wind energy evaluation, wind resource, or solar resource leases; and (3) Prospective lessees..., residential, business, wind energy evaluation, wind resource, and solar resource leases will not be advertised...

25 CFR 162.010 - How do I obtain a lease?

Code of Federal Regulations, 2013 CFR

2013-04-01

... subpart E for wind energy evaluation, wind resource, or solar resource leases; and (3) Prospective lessees..., residential, business, wind energy evaluation, wind resource, and solar resource leases will not be advertised...

Role of Concentrating Solar Power in Integrating Solar and Wind Energy: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, P.; Mehos, M.

2015-06-03

As wind and solar photovoltaics (PV) increase in penetration it is increasingly important to examine enabling technologies that can help integrate these resources at large scale. Concentrating solar power (CSP) when deployed with thermal energy storage (TES) can provide multiple services that can help integrate variable generation (VG) resources such as wind and PV. CSP with TES can provide firm, highly flexible capacity, reducing minimum generation constraints which limit penetration and results in curtailment. By acting as an enabling technology, CSP can complement PV and wind, substantially increasing their penetration in locations with adequate solar resource.

Handbook of solar-terrestrial data systems, version 1

NASA Technical Reports Server (NTRS)

1991-01-01

The interaction between the solar wind and the earth's magnetic field creates a large magnetic cavity which is termed the magnetosphere. Energy derived from the solar wind is ultimately dissipated by particle acceleration-precipitation and Joule heating in the magnetosphere-ionosphere. The rate of energy dissipation is highly variable, with peak levels during geomagnetic storms and substorms. The degree to which solar wind and magnetospheric conditions control the energy dissipation processes remains one of the major outstanding questions in magnetospheric physics. A conference on Solar Wind-Magnetospheric Coupling was convened to discuss these issues and this handbook is the result.

Role of the Coronal Alfvén Speed in Modulating the Solar-wind Helium Abundance

NASA Astrophysics Data System (ADS)

Wang, Y.-M.

2016-12-01

The helium abundance He/H in the solar wind is relatively constant at ˜0.04 in high-speed streams, but varies in phase with the sunspot number in slow wind, from ˜0.01 at solar minimum to ˜0.04 at maximum. Suggested mechanisms for helium fractionation have included frictional coupling to protons and resonant interactions with high-frequency Alfvénic fluctuations. We compare He/H measurements during 1995-2015 with coronal parameters derived from source-surface extrapolations of photospheric field maps. We find that the near-Earth helium abundance is an increasing function of the magnetic field strength and Alfvén speed v A in the outer corona, while being only weakly correlated with the proton flux density. Throughout the solar cycle, fast wind is associated with short-term increases in v A near the source surface; resonance with Alfvén waves, with v A and the relative speed of α-particles and protons decreasing with increasing heliocentric distance, may then lead to enhanced He/H at 1 au. The modulation of helium in slow wind reflects the tendency for the associated coronal Alfvén speeds to rise steeply from sunspot minimum, when this wind is concentrated around the source-surface neutral line, to sunspot maximum, when the source-surface field attains its peak strengths. The helium abundance near the source surface may represent a balance between collisional decoupling from protons and Alfvén wave acceleration.

Mapping the Solar Wind from its Source Region into the Outer Corona

NASA Technical Reports Server (NTRS)

Esser, Ruth

1998-01-01

Knowledge of the radial variation of the plasma conditions in the coronal source region of the solar wind is essential to exploring coronal heating and solar wind acceleration mechanisms. The goal of the present proposal is to determine as many plasma parameters in that region as possible by coordinating different observational techniques, such as Interplanetary Scintillation Observations, spectral line intensity observations, polarization brightness measurements and X-ray observations. The inferred plasma parameters are then used to constrain solar wind models.

Wind and Solar Resource Assessment of Sri Lanka and the Maldives (CD-ROM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, D.; Schwartz, M.; Scott, G.

2003-08-01

The Wind and Solar Resource Assessment of Sri Lanka and the Maldives CD contains an electronic version of Wind Energy Resource Atlas of Sri Lanka and the Maldives (NREL/TP-500-34518), Solar Resource Assessment for Sri Lanka and the Maldives (NREL/TO-710-34645), Sri Lanka Wind Farm Analysis and Site Selection Assistance (NREL/SR-500-34646), GIS Data Viewer (software and data files with a readme file), and Hourly Solar and Typical Meteorological Year Data with a readme file.

An Analysis of the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non Renewable Energy Sources

DTIC Science & Technology

2015-04-15

the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non Renewable Energy Sources Energy is a National...Park, NC 27709-2211 Energy Audits, Energy Conservation, Renewable Energy, Solar Energy, Wind Turbine Use, Energy Consumption REPORT DOCUMENTATION PAGE 11...in non peer-reviewed journals: An Analysis of the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non

An investigation of the effect of wind cooling on photovoltaic arrays

NASA Technical Reports Server (NTRS)

Wen, L.

1982-01-01

Convective cooling of photovoltaic modules for different wind conditions, including steady state controlled testing in a solar simulator and natural test environments in a field was investigated. Analytical thermal models of different module designs were used to correlate experimental data. The applicability of existing heat transfer correlations is confirmed. Reasonable agreement is obtained by applying a power law wind profile.

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.

The large-scale magnetic field in the solar wind. [astronomical models of interplanetary magnetics and the solar magnetic field

NASA Technical Reports Server (NTRS)

Burlaga, L. F.; Ness, N. F.

1976-01-01

A literature review is presented of theoretical models of the interaction of the solar wind and interplanetary magnetic fields. Observations of interplanetary magnetic fields by the IMP and OSO spacecraft are discussed. The causes for cosmic ray variations (Forbush decreases) by the solar wind are examined. The model of Parker is emphasized. This model shows the three dimensional magnetic field lines of the solar wind to have the form of spirals wrapped on cones. It is concluded that an out-of-the-ecliptic solar probe mission would allow the testing and verification of the various theoretical models examined. Diagrams of the various models are shown.

The Character of the Solar Wind, Surface Interactions, and Water

NASA Technical Reports Server (NTRS)

Farrell, William M.

2011-01-01

We discuss the key characteristics of the proton-rich solar wind and describe how it may interact with the lunar surface. We suggest that solar wind can be both a source and loss of water/OH related volatiles, and review models showing both possibilities. Energy from the Sun in the form of radiation and solar wind plasma are in constant interaction with the lunar surface. As such, there is a solar-lunar energy connection, where solar energy and matter are continually bombarding the lunar surface, acting at the largest scale to erode the surface at 0.2 Angstroms per year via ion sputtering [1]. Figure 1 illustrates this dynamically Sun-Moon system.

Use of meteorological information in the risk analysis of a mixed wind farm and solar

NASA Astrophysics Data System (ADS)

Mengelkamp, H.-T.; Bendel, D.

2010-09-01

Use of meteorological information in the risk analysis of a mixed wind farm and solar power plant portfolio H.-T. Mengelkamp*,** , D. Bendel** *GKSS Research Center Geesthacht GmbH **anemos Gesellschaft für Umweltmeteorologie mbH The renewable energy industry has rapidly developed during the last two decades and so have the needs for high quality comprehensive meteorological services. It is, however, only recently that international financial institutions bundle wind farms and solar power plants and offer shares in these aggregate portfolios. The monetary value of a mixed wind farm and solar power plant portfolio is determined by legal and technical aspects, the expected annual energy production of each wind farm and solar power plant and the associated uncertainty of the energy yield estimation or the investment risk. Building an aggregate portfolio will reduce the overall uncertainty through diversification in contrast to the single wind farm/solar power plant energy yield uncertainty. This is similar to equity funds based on a variety of companies or products. Meteorological aspects contribute to the diversification in various ways. There is the uncertainty in the estimation of the expected long-term mean energy production of the wind and solar power plants. Different components of uncertainty have to be considered depending on whether the power plant is already in operation or in the planning phase. The uncertainty related to a wind farm in the planning phase comprises the methodology of the wind potential estimation and the uncertainty of the site specific wind turbine power curve as well as the uncertainty of the wind farm effect calculation. The uncertainty related to a solar power plant in the pre-operational phase comprises the uncertainty of the radiation data base and that of the performance curve. The long-term mean annual energy yield of operational wind farms and solar power plants is estimated on the basis of the actual energy production and it's relation to a climatologically stable long-term reference period. These components of uncertainty are of technical nature and based on subjective estimations rather than on a statistically sound data analysis. And then there is the temporal and spatial variability of the wind speed and radiation. Their influence on the overall risk is determined by the regional distribution of the power plants. These uncertainty components are calculated on the basis of wind speed observations and simulations and satellite derived radiation data. The respective volatility (temporal variability) is calculated from the site specific time series and the influence on the portfolio through regional correlation. For an exemplary portfolio comprising fourteen wind farms and eight solar power plants the annual mean energy production to be expected is calculated, the different components of uncertainty are estimated for each single wind farm and solar power plant and for the portfolio as a whole. The reduction in uncertainty (or risk) through bundling the wind farms and the solar power plants (the portfolio effect) is calculated by Markowitz' Modern Portfolio Theory. This theory is applied separately for the wind farm and the solar power plant bundle and for the combination of both. The combination of wind and photovoltaic assets clearly shows potential for a risk reduction. Even assets with a comparably low expected return can lead to a significant risk reduction depending on their individual characteristics.

Solar wind stream evolution at large heliocentric distances - Experimental demonstration and the test of a model

NASA Technical Reports Server (NTRS)

Gosling, J. T.; Hundhausen, A. J.; Bame, S. J.

1976-01-01

A stream propagation model which neglects all dissipation effects except those occurring at shock interfaces, was used to compare Pioneer-10 solar wind speed observations, during the time when Pioneer 10, the earth, and the sun were coaligned, with near-earth Imp-7 observations of the solar wind structure, and with the theoretical predictions of the solar wind structure at Pioneer 10 derived from the Imp-7 measurements, using the model. The comparison provides a graphic illustration of the phenomenon of stream steepening in the solar wind with the attendant formation of forward-reverse shock pairs and the gradual decay of stream amplitudes with increasing heliocentric distance. The comparison also provides a qualitative test of the stream propagation model.

Measurements of the properties of solar wind plasma relevant to studies of its coronal sources

NASA Technical Reports Server (NTRS)

Neugebauer, M.

1982-01-01

Interplanetary measurements of the speeds, densities, abundances, and charge states of solar wind ions are diagnostic of conditions in the source region of the solar wind. The absolute values of the mass, momentum, and energy fluxes in the solar wind are not known to an accuracy of 20%. The principal limitations on the absolute accuracies of observations of solar wind protons and alpha particles arise from uncertain instrument calibrations, from the methods used to reduce the data, and from sampling biases. Sampling biases are very important in studies of alpha particles. Instrumental resolution and measurement ambiguities are additional major problems for the observation of ions heavier than helium. Progress in overcoming some of these measurement inadequacies is reviewed.

The Interaction Between the Magnetosphere of Mars and that of Comet Siding Spring

NASA Astrophysics Data System (ADS)

Holmstrom, M.; Futaana, Y.; Barabash, S. V.

2015-12-01

On 19 October 2014 the comet Siding Spring flew by Mars. This was a unique opportunity to study the interaction between a cometary and a planetary magnetosphere. Here we model the magnetosphere of the comet using a hybrid plasma solver (ions as particles, electrons as a fluid). The undisturbed upstream solar wind ion conditions are estimated from observations by ASPERA-3/IMA on Mars Express during several orbits. It is found that Mars probably passed through a solar wind that was disturbed by the comet during the flyby. The uncertainty derives from that the size of the disturbed solar wind region in the comet simulation is sensitive to the assumed upstream solar wind conditions, especially the solar wind proton density.

The South Pole, Antarctica, Solar Radio Telescope (SPASRT) System

NASA Astrophysics Data System (ADS)

Gerrard, A. J.; Weatherwax, A. T.; Gary, D. E.; Kujawski, J. T.; Nita, G. M.; Melville, R.; Stillinger, A.; Jeffer, G.

2014-12-01

The study of the sun in the radio portion of the electromagnetic spectrum furthers our understanding of fundamental solar processes observed in the X-ray, UV, and visible regions of the spectrum. For example, the study of solar radio bursts, which have been shown to cause serious disruptions of technologies at Earth, are essential for advancing our knowledge and understanding of solar flares and their relationship to coronal mass ejections and solar energetic particles, as well as the underlying particle acceleration mechanisms associated with these processes. In addition, radio coverage of the solar atmosphere could yield completely new insights into the variations of output solar energy, including Alfven wave propagation through the solar atmosphere and into the solar wind, which can potentially modulate and disturb the solar wind and Earth's geospace environment. In this presentation we discuss the development, construction, and testing of the South Pole, Antarctica, Solar Radio Telescope that is planned for installation at South Pole. The system will allow for 24-hour continuous, long-term observations of the sun across the 1-18 GHz frequency band and allow for truly continuous solar observations. We show that this system will enable unique scientific investigations of the solar atmosphere.

Global solar wind variations over the last four centuries

PubMed Central

Owens, M. J.; Lockwood, M.; Riley, P.

2017-01-01

The most recent “grand minimum” of solar activity, the Maunder minimum (MM, 1650–1710), is of great interest both for understanding the solar dynamo and providing insight into possible future heliospheric conditions. Here, we use nearly 30 years of output from a data-constrained magnetohydrodynamic model of the solar corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global solar wind variations over the last 400 years. Relative to the modern era, the MM shows a factor 2 reduction in near-Earth heliospheric magnetic field strength and solar wind speed, and up to a factor 4 increase in solar wind Mach number. Thus solar wind energy input into the Earth’s magnetosphere was reduced, resulting in a more Jupiter-like system, in agreement with the dearth of auroral reports from the time. The global heliosphere was both smaller and more symmetric under MM conditions, which has implications for the interpretation of cosmogenic radionuclide data and resulting total solar irradiance estimates during grand minima. PMID:28139769

Implementation of a Space Weather VOEvent service at IRAP in the frame of Europlanet H2020 PSWS

NASA Astrophysics Data System (ADS)

Gangloff, M.; André, N.; Génot, V.; Cecconi, B.; Le Sidaner, P.; Bouchemit, M.; Budnik, E.; Jourdane, N.

2017-09-01

Under Horizon 2020, the Europlanet Research Infrastructure includes PSWS (Planetary Space Weather Services), a set of new services that extend the concepts of space weather and space situation awareness to other planets of our solar system. One of these services is an Alert service associated in particular with an heliospheric propagator tool for solar wind predictions at planets, a meteor shower prediction tool, and a cometary tail crossing prediction tool. This Alert service, is based on VOEvent, an international standard proposed by the IVOA and widely used by the astronomy community. The VOEvent standard provides a means of describing transient celestial events in a machine-readable format. VOEvent is associated with VTP, the VOEvent Transfer Protocol that defines the system by which VOEvents may be disseminated to the community This presentation will focus on the enhancements of the VOEvent standard necessary to take into account the needs of the Solar System community and Comet, a freely available and open source implementation of VTP used by PSWS for its Alert service. Comet is implemented by several partners of PSWS, including IRAP and Observatoire de Paris. A use case will be presented for the heliospheric propagator tool based on extreme solar wind pressure pulses predicted at planets and probes from a 1D MHD model and real time observations of solar wind parameters.

Interpretation of the 12 May 2012 ground level enhancement event

NASA Astrophysics Data System (ADS)

Wu, C. C.; Dryer, Ph D., M.; Liou, K.; Wu, S. T.

2015-12-01

The 12 May 2012 solar event is associated with a moderate flare (M5.1) and, surprisingly, a ground level enhancement (GLE) event. It is the first GLE of the solar cycle 24 (or since December 2006). Because GLEs are considered as the highest energy tail in the solar energetic particle (SEP) spectrum, it is generally believed that GLEs must be generated at very strong shocks. Here, we conduct a simulation study of a number of major (> M5.0) flare events that occurred in the current solar cycle up to 2013, using the H3DMHD simulation code. The H3DMHD (Wu et al. 2007, JGR) combines the kinematic solar wind model (HAF) for regions near the solar surface (2.5-18 Rs) and a three-dimensional magnetohydrodynamics model (Han et al. 1988), which takes output from HAF at 18 Rs and propagates outward up to 1.7 AU. The H3DMHD code has been fully tested and is suitable for simulating not only the quiet solar wind, but also disturbances propagating in the solar wind. Our preliminary study result suggests that the 12 May 2012 was magnetically well connected, whereas others were not. We will present the detailed result, including the shock structure and intensity driven by the 12 May 2012 CME event, and discuss the result implication.

Radioactivites in returned lunar materials and in meteorites

NASA Technical Reports Server (NTRS)

Fireman, E. L.

1983-01-01

The cosmic-ray, solar-flare, and solar-wind bombardments of lunar rocks and soils and meteorites were studied by measurements of tritium, carbon-14 and argon radioactivity. The radioactivity integrates the bombardment for a time period equal to several half-lines. H-3, Ar-37, Ar-39, C-14. For the interior samples of lunar rocks and for deep lunar soil samples, the amounts of the radioactivities were equal to those calculated for galactic cosmic-ray interactions. The top near-surface samples of lunar rocks and the shallow lunar soil samples show excess amounts of the radioactivities attributable to solar flares. Lunar soil fines contain a large amount of hydrogen due to implanted solar wind. Studies of the H-3 in lunar soils and in recovered Surveyor-3 materials gave an upper limit for the H-3/H ratio in the solar wind of 10 to the -11th power. Solar wind carbon is also implanted on lunar soil fines. Lunar soils collected on the surface contained a 0.14 component attributable to implanted solar wind C-14. The C-14/H ratio attributed to the solar wind from this C-14 excess is approximately 4 x 10 to the -11th power.

Unintentional Insider Threats: A Review of Phishing and Malware Incidents

DTIC Science & Technology

2014-07-01

their agency as deliberate, malicious hackers [1]. This research supports the conclusions in the 2013 Verizon Data Breach Report that 47% of...References [1] SolarWinds. SolarWinds Federal Cybersecurity Survey Summary Report. SolarWinds, 2014. [2] Verizon. 2013 Data Breach Investigations

Dependence of Subsolar Magnetopause on Solar Wind Properties using the Magnetosphere Multiscale Mission

NASA Astrophysics Data System (ADS)

Russell, C. T.; Zhao, C.; Qi, Y.; Lai, H.; Strangeway, R. J.; Paterson, W. R.; Giles, B. L.; Baumjohann, W.; Torbert, R. B.; Burch, J.

2017-12-01

The nature of the solar wind interaction with the Earth's magnetic field depends on the balance between magnetic and plasma forces at the magnetopause. This balance is controlled by the magnetosonic Mach number of the bow shock standing in front of the magnetosphere. We have used measurements of the solar wind obtained in the near Earth solar wind to calculate this Mach number whenever MMS was near the magnetopause and in the subsolar region. In particular, we examine two intervals of magnetopause encounters when the solar wind Mach number was close to 2.0, one when the IMF was nearly due southward and one when it was due northward. The due southward magnetic field produced a rapidly oscillating boundary. The northward magnetic field produced a much more stable boundary but with a hot low density boundary layer between the magnetospheric and magnetosheath plasmas. These magnetopause crossings are quite different than those studied earlier under high solar wind Mach number conditions.

On the history of the solar wind discovery

NASA Astrophysics Data System (ADS)

Obridko, V. N.; Vaisberg, O. L.

2017-03-01

The discovery of the solar wind has been an outstanding achievement in heliophysics and space physics. The solar wind plays a crucial role in the processes taking place in the Solar System. In recent decades, it has been recognized as the main factor that controls the terrestrial effects of space weather. The solar wind is an unusual plasma laboratory of giant scale with a fantastic diversity of parameters and operating modes, and devoid of influence from the walls of laboratory plasma systems. It is also the only kind of stellar wind accessible for direct study. The history of this discovery is quite dramatic. Like many remarkable discoveries, it had several predecessors. However, the honor of a discovery usually belongs to a scientist who was able to more fully explain the phenomenon. Such a man is deservedly considered the US theorist Eugene Parker, who discovered the solar wind, as we know it today, almost "with the point of his pen". In 2017, we will celebrate the 90th anniversary birthday of Eugene Parker.

Solar Illumination Control of the Polar Wind

NASA Astrophysics Data System (ADS)

Maes, L.; Maggiolo, R.; De Keyser, J.; André, M.; Eriksson, A. I.; Haaland, S.; Li, K.; Poedts, S.

2017-11-01

Polar wind outflow is an important process through which the ionosphere supplies plasma to the magnetosphere. The main source of energy driving the polar wind is solar illumination of the ionosphere. As a result, many studies have found a relation between polar wind flux densities and solar EUV intensity, but less is known about their relation to the solar zenith angle at the ionospheric origin, certainly at higher altitudes. The low energy of the outflowing particles and spacecraft charging means it is very difficult to measure the polar wind at high altitudes. We take advantage of an alternative method that allows estimations of the polar wind flux densities far in the lobes. We analyze measurements made by the Cluster spacecraft at altitudes from 4 up to 20 RE. We observe a strong dependence on the solar zenith angle in the ion flux density and see that both the ion velocity and density exhibit a solar zenith angle dependence as well. We also find a seasonal variation of the flux density.

On the differences in element abundances of energetic ions from corotating events and from large solar events

NASA Technical Reports Server (NTRS)

Reames, D. V.; Richardson, I. G.; Barbier, L. M.

1991-01-01

The abundances of energetic ions accelerated from high-speed solar wind streams by shock waves formed at corotating interaction regions (CIRs) where high-speed streams overtake the lower-speed solar wind are examined. The observed element abundances appear to represent those of the high-speed solar wind, unmodified by the shock acceleration. These abundances, relative to those in the solar photosphere, are organized by the first ionization potential (FIP) of the ions in a way that is different from the FIP effect commonly used to describe differences between abundances in the solar photosphere and those in the solar corona, solar energetic particles (SEPs), and the low-speed solar wind. In contrast, the FIP effect of the ion abundances in the CIR events is characterized by a smaller amplitude of the differences between high-FIP and low-FIP ions and by elevated abundances of He, C, and S.

A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples.

PubMed

Marty, B; Chaussidon, M; Wiens, R C; Jurewicz, A J G; Burnett, D S

2011-06-24

The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material shows that implanted solar wind nitrogen has a (15)N/(14)N ratio of 2.18 ± 0.02 × 10(-3) (that is, ≈40% poorer in (15)N relative to terrestrial atmosphere). The (15)N/(14)N ratio of the protosolar nebula was 2.27 ± 0.03 × 10(-3), which is the lowest (15)N/(14)N ratio known for solar system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent solar system and accounts for the (15)N-depleted components observed in solar system reservoirs.

Nature of Fluctuations on Directional Discontinuities Inside a Solar Ejection: Wind and IMP 8 Observations

NASA Technical Reports Server (NTRS)

Vasquez, Bernard J.; Farrugia, Charles J.; Markovskii, Sergei A.; Hollweg, Joseph V.; Richardson, Ian G.; Ogilvie, Keith W.; Lepping, Ronald P.; Lin, Robert P.; Larson, Davin; White, Nicholas E. (Technical Monitor)

2001-01-01

A solar ejection passed the Wind spacecraft between December 23 and 26, 1996. On closer examination, we find a sequence of ejecta material, as identified by abnormally low proton temperatures, separated by plasmas with typical solar wind temperatures at 1 AU. Large and abrupt changes in field and plasma properties occurred near the separation boundaries of these regions. At the one boundary we examine here, a series of directional discontinuities was observed. We argue that Alfvenic fluctuations in the immediate vicinity of these discontinuities distort minimum variance normals, introducing uncertainty into the identification of the discontinuities as either rotational or tangential. Carrying out a series of tests on plasma and field data including minimum variance, velocity and magnetic field correlations, and jump conditions, we conclude that the discontinuities are tangential. Furthermore, we find waves superposed on these tangential discontinuities (TDs). The presence of discontinuities allows the existence of both surface waves and ducted body waves. Both probably form in the solar atmosphere where many transverse nonuniformities exist and where theoretically they have been expected. We add to prior speculation that waves on discontinuities may in fact be a common occurrence. In the solar wind, these waves can attain large amplitudes and low frequencies. We argue that such waves can generate dynamical changes at TDs through advection or forced reconnection. The dynamics might so extensively alter the internal structure that the discontinuity would no longer be identified as tangential. Such processes could help explain why the occurrence frequency of TDs observed throughout the solar wind falls off with increasing heliocentric distance. The presence of waves may also alter the nature of the interactions of TDs with the Earth's bow shock in so-called hot flow anomalies.

Comparison of Density Measurements on ACE and WIND

NASA Astrophysics Data System (ADS)

Fowler, G.; Russell, C. T.

2001-12-01

In studying the compression of the magnetosphere by the solar wind we have used data publically available on the CDA Web site and the ACE website. The solar wind velocities measured by these two spacecraft agree well but the densities do not. The density reported by WIND is on average only 75% of that reported by ACE. This ratio does not appear to be a constant, however. It seems to vary with the solar wind velocity.

Evidence for the distribution of angular velocity inside the sun and stars

NASA Technical Reports Server (NTRS)

1972-01-01

A round table discussion of problems of solar and stellar spindown and theory is presented. Observational evidence of the angular momentum of the solar wind is included, emphasizing the distribution of angular velocity inside the sun and stars.

3-D Hybrid Kinetic Modeling of the Interaction Between the Solar Wind and Lunar-like Exospheric Pickup Ions in Case of Oblique/ Quasi-Parallel/Parallel Upstream Magnetic Field

NASA Technical Reports Server (NTRS)

Lipatov, A. S.; Farrell, W. M.; Cooper, J. F.; Sittler, E. C., Jr.; Hartle, R. E.

2015-01-01

The interactions between the solar wind and Moon-sized objects are determined by a set of the solar wind parameters and plasma environment of the space objects. The orientation of upstream magnetic field is one of the key factors which determines the formation and structure of bow shock wave/Mach cone or Alfven wing near the obstacle. The study of effects of the direction of the upstream magnetic field on lunar-like plasma environment is the main subject of our investigation in this paper. Photoionization, electron-impact ionization and charge exchange are included in our hybrid model. The computational model includes the self-consistent dynamics of the light (hydrogen (+), helium (+)) and heavy (sodium (+)) pickup ions. The lunar interior is considered as a weakly conducting body. Our previous 2013 lunar work, as reported in this journal, found formation of a triple structure of the Mach cone near the Moon in the case of perpendicular upstream magnetic field. Further advances in modeling now reveal the presence of strong wave activity in the upstream solar wind and plasma wake in the cases of quasiparallel and parallel upstream magnetic fields. However, little wave activity is found for the opposite case with a perpendicular upstream magnetic field. The modeling does not show a formation of the Mach cone in the case of theta(Sub B,U) approximately equal to 0 degrees.

Control of particle precipitation by energy transfer from solar wind

NASA Astrophysics Data System (ADS)

Bremer, J.; Gernandt, H.

1985-12-01

The energy transfer function (epsilon), introduced by Perreault and Akasofu (1978), appears to be well suited for the description of the long-term control of the particle precipitation by interplanetary parameters. An investigation was conducted with the objective to test this control in more detail. This investigation included the calculation of hourly epsilon values on the basis of satellite-measured solar wind and IMF (interplanetary magnetic field) data. The results were compared with corresponding geomagnetic and ionospheric data. The ionospheric data had been obtained by three GDR (German Democratic Republic) teams during the 21st, 22nd, and 23rd Soviet Antarctic Expeditions in the time period from 1976 to 1979. It was found that, in high latitudes, the properties of the solar wind exercise a pronounced degree of control on the precipitation of energetic particles into the atmosphere, taking into account a time delay of about one hour due to the occurrence of magnetospheric storage processes.

Three Proposed Compendia for Genesis Solar Wind Samples: Science Results, Collector Materials Characterization and Cleaning Techniques

NASA Technical Reports Server (NTRS)

Allton, J. H.; Calaway, M. J.; Nyquist, L. E.; Jurewicz, A. J. G.; Burnett, D. S.

2018-01-01

Final Paper and not the abstract is attached. Introduction: Planetary material and cosmochemistry research using Genesis solar wind samples (including the development and implementation of cleaning and analytical techniques) has matured sufficiently that compilations on several topics, if made publically accessible, would be beneficial for researchers and reviewers. We propose here three compendia based on content, organization and source of documents (e.g. published peer-reviewed, published, internal memos, archives). For planning purposes, suggestions are solicited from potential users of Genesis solar wind samples for the type of science content and/or organizational style that would be most useful to them. These compendia are proposed as living documents, periodically updated. Similar to the existing compendia described below, the curation compendia are like library or archival finding aids, they are guides to published or archival documents and should not be cited as primary sources.

The Sun as a star

NASA Technical Reports Server (NTRS)

Jordan, S. D. (Editor)

1981-01-01

Solar physics was reviewed in the context of the solar atmoshere. The understanding of the solar atmosphere is linked to stellar atmospheric research. Topics covered include: the existence of the chromosphere, the corona, and the solar wind; the interactive complex of convection, differential rotation, magnetic field generation and concentration, and the activity cycle; phenomena such as granulation, supergranulation, the 5 minute oscillation, filigree, faculae, sunspots, spicules, prominences, surges, and the spectacular flares.

Characterization of the Martian magnetic topology response to extreme solar transient events with MGS data

NASA Astrophysics Data System (ADS)

Xu, S.; Curry, S.; Mitchell, D. L.; Luhmann, J. G.; Lillis, R. J.; Dong, C.

2017-12-01

Characterizing how the solar cycle affects the physics of the Mars-solar wind interaction can improve our understanding of Mars' atmospheric evolution and the plasma environment at Mars. In particular, solar transient events such as Interplanetary Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs) significantly change the solar-wind interaction, including the magnetic topology and ion acceleration. However, both the Mars Express and Mars Atmosphere Volatile EvolutioN (MAVEN) missions have encountered relatively few extreme solar transient events due to the recent low solar activity (2004-2017). In contrast, Mars Global Surveyor (MGS) was operating during a relatively active solar maximum (1999-2003). Based on new results from MAVEN, this study reanalyzes MGS data to better understand how the Martian plasma environment responds to extreme solar events. In particular, we aim to investigate how the magnetic topology during these extreme events differs from the topology during quiet times. We conduct orbit comparisons of the magnetic topology inferred from MGS electron pitch angle distributions during quiet periods and extreme events to determine how the open and closed field patterns respond to extreme events.

Evolution of energy-containing turbulent eddies in the solar wind

NASA Technical Reports Server (NTRS)

Matthaeus, William H.; Oughton, Sean; Pontius, Duane H., Jr.; Zhou, YE

1994-01-01

Previous theoretical treatments of fluid-scale turbulence in the solar wind have concentrated on describing the state and dynamical evolution of fluctuations in the inertial range, which are characterized by power law energy spectra. In the present paper a model for the evolution of somewhat larger, more energetic magnetohydrodynamic (MHD) fluctuations is developed by analogy with classical hydrodynamic turbulence in the quasi-equilibrium range. The model is constructed by assembling and extending existing phenomenologies of homogeneous MHD turbulence, as well as simple two-length-scale models for transport of MHD turbulence in a weekly inhomogeneous medium. A set of equations is presented for the evolution of the turbulence, including the transport and nonlinear evolution of magnetic and kinetic energy, cross helicity, and their correlation scales. Two versions of the model are derived, depending on whether the fluctuations are distributed isotropically in three dimensions or restricted to the two-dimensional plane perpendicular to the mean magnetic field. This model includes a number of potentially important physical effects that have been neglected in previous discussions of transport of solar wind turbulence.

Solar- and wind-powered irrigation systems

NASA Astrophysics Data System (ADS)

Enochian, R. V.

1982-02-01

Five different direct solar and wind energy systems are technically feasible for powering irrigation pumps. However, with projected rates of fossil fuel costs, only two may produce significant unsubsidied energy for irrigation pumping before the turn of the century. These are photovoltaic systems with nonconcentrating collectors (providing that projected costs of manufacturing solar cells prove correct); and wind systems, especially in remote areas where adequate wind is available.

Modeling energy production of solar thermal systems and wind turbines for installation at corn ethanol plants

NASA Astrophysics Data System (ADS)

Ehrke, Elizabeth

Nearly every aspect of human existence relies on energy in some way. Most of this energy is currently derived from fossil fuel resources. Increasing energy demands coupled with environmental and national security concerns have facilitated the move towards renewable energy sources. Biofuels like corn ethanol are one of the ways the U.S. has significantly reduced petroleum consumption. However, the large energy requirement of corn ethanol limits the net benefit of the fuel. Using renewable energy sources to produce ethanol can greatly improve its economic and environmental benefits. The main purpose of this study was to model the useful energy received from a solar thermal array and a wind turbine at various locations to determine the feasibility of applying these technologies at ethanol plants around the country. The model calculates thermal energy received from a solar collector array and electricity generated by a wind turbine utilizing various input data to characterize the equipment. Project cost and energy rate inputs are used to evaluate the profitability of the solar array or wind turbine. The current state of the wind and solar markets were examined to give an accurate representation of the economics of each industry. Eighteen ethanol plant locations were evaluated for the viability of a solar thermal array and/or wind turbine. All ethanol plant locations have long payback periods for solar thermal arrays, but high natural gas prices significantly reduce this timeframe. Government incentives will be necessary for the economic feasibility of solar thermal arrays. Wind turbines can be very profitable for ethanol plants in the Midwest due to large wind resources. The profitability of wind power is sensitive to regional energy prices. However, government incentives for wind power do not significantly change the economic feasibility of a wind turbine. This model can be used by current or future ethanol facilities to investigate or begin the planning process for a solar thermal array or wind turbine. The model is meant to aide in the planning stages of a renewable energy project, and advanced investigation will be needed to move forward with that project.

Plasma-field Coupling at Small Length Scales in Solar Wind Near 1 AU

NASA Astrophysics Data System (ADS)

Livadiotis, G.; Desai, M. I.

2016-10-01

In collisionless plasmas such as the solar wind, the coupling between plasma constituents and the embedded magnetic field occurs on various temporal and spatial scales, and is primarily responsible for the transfer of energy between waves and particles. Recently, it was shown that the transfer of energy between solar wind plasma particles and waves is governed by a new and unique relationship: the ratio between the magnetosonic energy and the plasma frequency is constant, E ms/ω pl ˜ ℏ*. This paper examines the variability and substantial departure of this ratio from ℏ* observed at ˜1 au, which is caused by a dispersion of fast magnetosonic (FMS) waves. In contrast to the efficiently transferred energy in the fast solar wind, the lower efficiency of the slow solar wind can be caused by this dispersion, whose relation and characteristics are derived and studied. In summary, we show that (I) the ratio E ms/ω pl transitions continuously from the slow to the fast solar wind, tending toward the constant ℏ* (II) the transition is more efficient for larger thermal, Alfvén, or FMS speeds; (III) the fast solar wind is almost dispersionless, characterized by quasi-constant values of the FMS speed, while the slow wind is subject to dispersion that is less effective for larger wind or magnetosonic speeds; and (IV) the constant ℏ* is estimated with the best known precision, ℏ* ≈ (1.160 ± 0.083) × 10-22 Js.

Interplanetary Magnetic Field Power Spectrum Variations: A VHO Enabled Study

NASA Astrophysics Data System (ADS)

Szabo, A.; Koval, A.; Merka, J.; Narock, T. W.

2010-12-01

The newly reprocessed high time resolution (11/22 vectors/sec) Wind mission interplanetary magnetic field data and the solar wind key parameter search capability of the Virtual Heliospheric Observatory (VHO) affords an opportunity to study magnetic field power spectral density variations as a function of solar wind conditions. In the reprocessed Wind Magnetic Field Investigation (MFI) data, the spin tone and its harmonics are greatly reduced that allows the meaningful fitting of power spectra to the ~2 Hz limit above which digitization noise becomes apparent. The power spectral density is computed and the spectral index is fitted for the MHD and ion inertial regime separately along with the break point between the two for various solar wind conditions . The time periods of fixed solar wind conditions are obtained from VHO searches that greatly simplify the process. The functional dependence of the ion inertial spectral index and break point on solar wind plasma and magnetic field conditions will be discussed.

Reduction and Analysis of Data from the IMP 8 Spacecraft

NASA Technical Reports Server (NTRS)

2003-01-01

The IMP 8 spacecraft was launched in 1973 and the MIT solar wind Faraday Cup experiment continues to produce excellent data except for a slightly increased noise level. Those data have been important for determining the solar wind interaction with Earth's magnetic field; studies of interplanetary shocks; studies of the correlation lengths of solar wind features through comparisons with other spacecraft; and more recently, especially important for determination of the regions in which the Wind spacecraft was taking data as it passed through Earth's magnetotail and for understanding the propagation of solar wind features from near 1 AU to the two Voyager spacecraft.

2017 Annual Technology Baseline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, Wesley J; Hand, M. M; Eberle, Annika

Consistent cost and performance data for various electricity generation technologies can be difficult to find and may change frequently for certain technologies. With the Annual Technology Baseline (ATB), the National Renewable Energy Laboratory annually provides an organized and centralized set of such cost and performance data. The ATB uses the best information from the Department of Energy national laboratories' renewable energy analysts as well as information from the Energy Information Administration for fuel-based technologies. The ATB has been reviewed by experts and it includes the following electricity generation technologies: land-based wind, offshore wind, utility-scale solar photovoltaics (PV), commercial-scale solar PV,more » residential-scale solar PV, concentrating solar power, geothermal power, hydropower, coal, natural gas, nuclear, and conventional biopower. This webinar presentation introduces the 2017 ATB.« less

Hydrogen Generation Through Renewable Energy Sources at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Colozza, Anthony; Prokopius, Kevin

2007-01-01

An evaluation of the potential for generating high pressure, high purity hydrogen at the NASA Glenn Research Center (GRC) was performed. This evaluation was based on producing hydrogen utilizing a prototype Hamilton Standard electrolyzer that is capable of producing hydrogen at 3000 psi. The present state of the electrolyzer system was determined to identify the refurbishment requirements. The power for operating the electrolyzer would be produced through renewable power sources. Both wind and solar were considered in the analysis. The solar power production capability was based on the existing solar array field located at NASA GRC. The refurbishment and upgrade potential of the array field was determined and the array output was analyzed with various levels of upgrades throughout the year. The total available monthly and yearly energy from the array was determined. A wind turbine was also sized for operation. This sizing evaluated the wind potential at the site and produced an operational design point for the wind turbine. Commercially available wind turbines were evaluated to determine their applicability to this site. The system installation and power integration were also addressed. This included items such as housing the electrolyzer, power management, water supply, gas storage, cooling and hydrogen dispensing.

Wind and solar powered turbine

NASA Technical Reports Server (NTRS)

Wells, I. D.; Koh, J. L.; Holmes, M. (Inventor)

1984-01-01

A power generating station having a generator driven by solar heat assisted ambient wind is described. A first plurality of radially extendng air passages direct ambient wind to a radial flow wind turbine disposed in a centrally located opening in a substantially disc-shaped structure. A solar radiation collecting surface having black bodies is disposed above the fist plurality of air passages and in communication with a second plurality of radial air passages. A cover plate enclosing the second plurality of radial air passages is transparent so as to permit solar radiation to effectively reach the black bodies. The second plurality of air passages direct ambient wind and thermal updrafts generated by the black bodies to an axial flow turbine. The rotating shaft of the turbines drive the generator. The solar and wind drien power generating system operates in electrical cogeneration mode with a fuel powered prime mover.

Dust removal from solar cells

NASA Technical Reports Server (NTRS)

Ashpis, David E. (Inventor)

2011-01-01

A solar panel cleaning device includes a solar panel having a plurality of photovoltaic cells arranged in rows and embedded in the solar panel with space between the rows. A transparent dielectric overlay is affixed to the solar panel. A plurality of electrode pairs each of which includes an upper and a lower electrode are arranged on opposite sides of the transparent dielectric and are affixed thereto. The electrodes may be transparent electrodes which may be arranged without concern for blocking sunlight to the solar panel. The solar panel may be a dielectric and its dielectric properties may be continuously and spatially variable. Alternatively the dielectric used may have dielectric segments which produce different electrical field and which affects the wind "generated."

Dust Removal from Solar Cells

NASA Technical Reports Server (NTRS)

Ashpis, David E. (Inventor)

2015-01-01

A solar panel cleaning device includes a solar panel having a plurality of photovoltaic cells arranged in rows and embedded in the solar panel with space between the rows. A transparent dielectric overlay is affixed to the solar panel. A plurality of electrode pairs each of which includes an upper and a lower electrode are arranged on opposite sides of the transparent dielectric and are affixed thereto. The electrodes may be transparent electrodes which may be arranged without concern for blocking sunlight to the solar panel. The solar panel may be a dielectric and its dielectric properties may be continuously and spatially variable. Alternatively the dielectric used may have dielectric segments which produce different electrical field and which affects the wind "generated."

Charge exchange, ENAs and the loss of planetary ions at Mars

NASA Astrophysics Data System (ADS)

Kallio, E.; Janhunen, P.; Säles, T.

Neither Mars nor Venus has a strong global intrinsic magnetic field and therefore the solar wind can flow close to the planets in high neutral density regions. Because of the formed direct interaction between the atmosphere/exosphere and the solar wind, the ionized atmospheric neutrals can be picked up by the solar wind. Charge exchange between solar wind protons and planetary neutrals, instead, produce energetic neutral hydrogen atoms (H-ENA) which are the manifestation of the direct interaction between the solar wind and planetary neutrals. Picked-up planetary O+ ions in turn form energetic neutral oxygen atoms (O-ENA) via charge exchange process. The ion escape, H-ENAs, O-ENAs and electrons will be investigated at Mars and Venus by two identical instruments: ASPERA-3 on MarsExpress (measurements started in Jan. 2004) and ASPERA-4 on VenusExpress (2006). We present a self-consistent, three-dimensional quasi-neutral hybrid (ions are particles, electrons a fluid) simulation to study Mars/Venus-solar wind interaction in general and ASPERA-3/4 measurements in particular. Our model includes three ion species (H+, O+, O2+), and contains charge exchange, ion-neutral and chemical reactions. We show results of quasi-neutral hybrid model runs that we have used to study the escape of planetary ions, the effects of planetary ions on the Martian plasma environment and the production and properties of fast hydrogen(H) and oxygen(O) ENAs near Mars. We also compare these hydrogen ENA images with the hydrogen ENA images that has been derived from an empirical flow model by line-of-sight integration. The advantage of the analytical gas dynamic like flow model is that it is computationally so fast that it provides a possibility to perform an ENA inversion, that is, to derive global plasma parameters from the measured ENA image.

Three dimensional Particle-in-Cell (PIC) simulations of the 67P environment

NASA Astrophysics Data System (ADS)

Divin, Andrey; Deca, Jan; Henri, Pierre; Horanyi, Mihaly; Markidis, Stefano; Lapenta, Giovanni; Olshevsky, Vyacheslav; Eriksson, Anders

2017-04-01

ESA's Rosetta orbiter spacecraft escorted comet 67P/Churyumov-Gerasimenko for two years, carrying 21 scientific instruments. Five of those were dedicated to plasma measurements. The mission revealed for the first time, and in unprecedented detail, the fascinating evolution of a comet and its interaction with our Sun as it races along its 6.45yr elliptical orbit around the Sun. Using a self-consistent 3-D fully kinetic electromagnetic particle-in-cell approach, we focus on the global cometary environment and, in particular, on the collisionless electron-kinetic interaction. We include cometary ions and electrons produced by the ionization of the outgassing cometary atmosphere in addition to the solar wind ion and electron plasma flow. We approximate mass-loading of the cold cometary ion and electron populations using a 1/r relation with distance to the comet with a total neutral production rate of Q = 1026 s-1. Our simulation results disentangle for the first time the kinetic ion and electron dynamics of the solar wind interaction with a weakly outgassing comet. The simulated global structure of the solar wind-comet interaction confirms the results reported in hybrid simulations of the induced cometary magnetosphere. Moreover, we show that cometary and solar wind electrons neutralize the solar wind protons and cometary ions, respectively, in the region of influence around the comet, representing to first order a four-fluid behavior. The electron energy distribution close to the comet is shown to be a mix of cometary and solar wind electrons that appear as, respectively, a thermal and a suprathermal components. Analyzing ion and electron energy distribution functions, and comparing with plasma measurements from ESA's Rosetta mission to comet 67P/Churyumov-Gerasimenko, we conclude that a detailed kinetic treatment of the electron dynamics is critical to fully capture the complex physics of mass-loading plasmas.

Classification of Initial conditions required for Substorm prediction.

NASA Astrophysics Data System (ADS)

Patra, S.; Spencer, E. A.

2014-12-01

We investigate different classes of substorms that occur as a result of various drivers such as the conditions in the solar wind and the internal state of the magnetosphere ionosphere system during the geomagnetic activity. In performing our study, we develop and use our low order physics based nonlinear model of the magnetosphere called WINDMI to establish the global energy exchange between the solar wind, magnetosphere and ionosphere by constraining the model results to satellite and ground measurements. On the other hand, we make quantitative and qualitative comparisons between our low order model with available MHD, multi-fluid and ring current simulations in terms of the energy transfer between the geomagnetic tail, plasma sheet, field aligned currents, ionospheric currents and ring current, during isolated substorms, storm time substorms, and sawtooth events. We use high resolution solar wind data from the ACE satellite, measurements from the CLUSTER and THEMIS missions satellites, and ground based magnetometer measurements from SUPERMAG and WDC Kyoto, to further develop our low order physics based model. Finally, we attempt to answer the following questions: 1) What conditions in the solar wind influence the type of substorm event. This includes the IMF strength and orientation, the particle densities, velocities and temperatures, and the timing of changes such as shocks, southward turnings or northward turnings of the IMF. 2) What is the state of the magnetosphere ionosphere system before an event begins. These are the steady state conditions prior to an event, if they exist, which produce the satellite and ground based measurements matched to the WINDMI model. 3) How does the prior state of the magnetosphere influence the transition into a particular mode of behavior under solar wind forcing. 4) Is it possible to classify the states of the magnetosphere into distinct categories depending on pre-conditioning, and solar wind forcing conditions? 5) Can we predict the occurrence of substorms with any confidence?

Energy and Mass Transport of Magnetospheric Plasmas during the November 2003 Magnetic Storm

NASA Technical Reports Server (NTRS)

Fok, Mei-Chging; Moore, Thomas

2008-01-01

Intensive energy and mass transport from the solar wind across the magnetosphere boundary is a trigger of magnetic storms. The storm on 20-21 November 2003 was elicited by a high-speed solar wind and strong southward component of interplanetary magnetic field. This storm attained a minimum Dst of -422 nT. During the storm, some of the solar wind particles enter the magnetosphere and eventually become part of the ring current. At the same time, the fierce solar wind powers strong outflow of H+ and O+ from the ionosphere, as well as from the plasmasphere. We examine the contribution of plasmas from the solar wind, ionosphere and plasmasphere to the storm-time ring current. Our simulation shows, for this particular storm, ionospheric O+ and solar wind ions are the major sources of the ring current particles. The polar wind and plasmaspheric H+ have only minor impacts. In the storm main phase, the strong penetration of solar wind electric field pushes ions from the geosynchronous orbit to L shells of 2 and below. Ring current is greatly intensified during the earthward transport and produces a large magnetic depression in the surface field. When the convection subsides, the deep penetrating ions experience strong charge exchange loss, causing rapid decay of the ring current and fast initial storm recovery. Our simulation reproduces very well the storm development indicated by the Dst index.

Fluid Aspects of Solar Wind Disturbances Driven by Coronal Mass Ejections. Appendix 3

NASA Technical Reports Server (NTRS)

Gosling, J. T.; Riley, Pete

2001-01-01

Transient disturbances in the solar wind initiated by coronal eruptions have been modeled for many years, beginning with the self-similar analytical models of Parker and Simon and Axford. The first numerical computer code (one-dimensional, gas dynamic) to study disturbance propagation in the solar wind was developed in the late 1960s, and a variety of other codes ranging from simple one-dimensional gas dynamic codes through three-dimensional gas dynamic and magnetohydrodynamic codes have been developed in subsequent years. For the most part, these codes have been applied to the problem of disturbances driven by fast CMEs propagating into a structureless solar wind. Pizzo provided an excellent summary of the level of understanding achieved from such simulation studies through about 1984, and other reviews have subsequently become available. More recently, some attention has been focused on disturbances generated by slow CMEs, on disturbances driven by CMEs having high internal pressures, and disturbance propagation effects associated with a structured ambient solar wind. Our purpose here is to provide a brief tutorial on fluid aspects of solar wind disturbances derived from numerical gas dynamic simulations. For the most part we illustrate disturbance evolution by propagating idealized perturbations, mimicking different types of CMEs, into a structureless solar wind using a simple one-dimensional, adiabatic (except at shocks), gas dynamic code. The simulations begin outside the critical point where the solar wind becomes supersonic and thus do not address questions of how the CMEs themselves are initiated. Limited to one dimension (the radial direction), the simulation code predicts too strong an interaction between newly ejected solar material and the ambient wind because it neglects azimuthal and meridional motions of the plasma that help relieve pressure stresses. Moreover, the code ignores magnetic forces and thus also underestimates the speed with which pressure disturbances propagate in the wind.

Properties of Minor Ions in the Solar Wind and Implications for the Background Solar Wind Plasma

NASA Technical Reports Server (NTRS)

Wagner, William (Technical Monitor); Esser, Ruth

2004-01-01

The scope of the investigation is to extract information on the properties of the bulk solar wind from the minor ion observations that are provided by instruments on board NASA space craft and theoretical model studies. Ion charge states measured in situ in interplanetary space are formed in the inner coronal regions below 5 solar radii, hence they carry information on the properties of the solar wind plasma in that region. The plasma parameters that are important in the ion forming processes are the electron density, the electron temperature and the flow speeds of the individual ion species. In addition, if the electron distribution function deviates from a Maxwellian already in the inner corona, then the enhanced tail of that distribution function, also called halo, greatly effects the ion composition. This study is carried out using solar wind models, coronal observations, and ion calculations in conjunction with the in situ observations.

The variety of MHD shock waves interactions in the solar wind flow

NASA Technical Reports Server (NTRS)

Grib, S. A.

1995-01-01

Different types of nonlinear shock wave interactions in some regions of the solar wind flow are considered. It is shown, that the solar flare or nonflare CME fast shock wave may disappear as the result of the collision with the rotational discontinuity. By the way the appearance of the slow shock waves as the consequence of the collision with other directional discontinuity namely tangential is indicated. Thus the nonlinear oblique and normal MHD shock waves interactions with different solar wind discontinuities (tangential, rotational, contact, shock and plasmoidal) both in the free flow and close to the gradient regions like the terrestrial magnetopause and the heliopause are described. The change of the plasma pressure across the solar wind fast shock waves is also evaluated. The sketch of the classification of the MHD discontinuities interactions, connected with the solar wind evolution is given.

Interplanetary ions during an energetic storm particle event - The distribution function from solar wind thermal energies to 1.6 MeV

NASA Technical Reports Server (NTRS)

Gosling, J. T.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Zwickl, R. D.; Paschmann, G.; Sckopke, N.; Hynds, R. J.

1981-01-01

An ion velocity distribution function of the postshock phase of an energetic storm particle (ESP) event is obtained from data from the ISEE 2 and ISEE 3 experiments. The distribution function is roughly isotropic in the solar wind frame from solar wind thermal energies to 1.6 MeV. The ESP event studied (8/27/78) is superposed upon a more energetic particle event which was predominantly field-aligned and which was probably of solar origin. The observations suggest that the ESP population is accelerated directly out of the solar wind thermal population or its quiescent suprathermal tail by a stochastic process associated with shock wave disturbance. The acceleration mechanism is sufficiently efficient so that approximately 1% of the solar wind population is accelerated to suprathermal energies. These suprathermal particles have an energy density of approximately 290 eV cubic centimeters.

Thermodynamic characteristics of a novel wind-solar-liquid air energy storage system

NASA Astrophysics Data System (ADS)

Ji, W.; Zhou, Y.; Sun, Y.; Zhang, W.; Pan, C. Z.; Wang, J. J.

2017-12-01

Due to the nature of fluctuation and intermittency, the utilization of wind and solar power will bring a huge impact to the power grid management. Therefore a novel hybrid wind-solar-liquid air energy storage (WS-LAES) system was proposed. In this system, wind and solar power are stored in the form of liquid air by cryogenic liquefaction technology and thermal energy by solar thermal collector, respectively. Owing to the high density of liquid air, the system has a large storage capacity and no geographic constraints. The WS-LAES system can store unstable wind and solar power for a stable output of electric energy and hot water. Moreover, a thermodynamic analysis was carried out to investigate the best system performance. The result shows that the increases of compressor adiabatic efficiency, turbine inlet pressure and inlet temperature all have a beneficial effect.

Solar wind and coronal structure near sunspot minimum - Pioneer and SMM observations from 1985-1987

NASA Technical Reports Server (NTRS)

Mihalov, J. D.; Barnes, A.; Hundhausen, A. J.; Smith, E. J.

1990-01-01

Changes in solar wind speed and magnetic polarity observed at the Pioneer spacecraft are discussed here in terms of the changing magnetic geometry implied by SMM coronagraph observations over the period 1985-1987. The pattern of recurrent solar wind streams, the long-term average speed, and the sector polarity of the interplanetary magnetic field all changed in a manner suggesting both a temporal variation, and a changing dependence on heliographic latitude. Coronal observations during this epoch show a systematic variation in coronal structure and the magnetic structure imposed on the expanding solar wind. These observations suggest interpretation of the solar wind speed variations in terms of the familiar model where the speed increases with distance from a nearly flat interplanetary current sheet, and where this current sheet becomes aligned with the solar equatorial plane as sunspot minimum approaches, but deviates rapidly from that orientation after minimum.

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

NASA Astrophysics Data System (ADS)

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

2017-09-01

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

FIP effect for minor heavy solar wind ions as seen with SOHO/CELIAS/MTOF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heidrich-Meisner, Verena, E-mail: heidrich@physik.uni-kiel.de; Berger, Lars; Wimmer-Schweingruber, Robert F.

A recent paper [Shearer et al., 2014] reported that during solar maximum Ne showed a surprisingly low abundance. This leads to the question whether other elements show the same behavior. The good mass resolution of Mass-Time-Of-Flight (MTOF) as part of the Charge ELement and Isotope Analysis System (CELIAS) on the Solar Helioshperic Observatory (SOHO) allows to investigate the composition of heavy minor elements in different types of solar wind. We restrict this study to slow solar wind, where the characterisation of slow solar wind is taken from Xu and Borovsky, 2014. This classification scheme requires magnet field information. Since SOHOmore » does not carry a magnetometer, we use the Magnetometer (MAG) of the Advanced Composition Explorer (ACE) instead. The Solar Wind Ion Composition Spectrometer (ACE/SWICS) also provides composition data for cross-calibration and charge-state distributions as input for the transmission function of MTOF whenever the two spacecraft can be expected to observe the same type of wind. We illustrate the MTOF’s capability to determine the solar wind abundance compared to the photospheric abundance (called the FIP ratio in the following) for rare elements like Ti or Cr on long-time scales as a proof of concept for our analysis. And in this brief study, measurements with both ACE/SWICS indicate that the observed elements exhibit a (weak) dependence on the solar cycle, whereas the MTOF measurements are inconclusive.« less

Fading Coronal Structure and the Onset of Turbulence in the Young Solar Wind

NASA Technical Reports Server (NTRS)

DeForest, C. E.; Matthaeus, W. H.; Viall, N. M.; Cranmer, S. R.

2016-01-01

Above the top of the solar corona, the young, slow solar wind transitions from low-beta, magnetically structured flow dominated by radial structures to high-beta, less structured flow dominated by hydrodynamics. This transition, long inferred via theory, is readily apparent in the sky region close to 10deg from the Sun in processed, background-subtracted solar wind images. We present image sequences collected by the inner Heliospheric Imager instrument on board the Solar-Terrestrial Relations Observatory (STEREO/HI1) in 2008 December, covering apparent distances from approximately 4deg to 24deg from the center of the Sun and spanning this transition in the large-scale morphology of the wind. We describe the observation and novel techniques to extract evolving image structure from the images, and we use those data and techniques to present and quantify the clear textural shift in the apparent structure of the corona and solar wind in this altitude range. We demonstrate that the change in apparent texture is due both to anomalous fading of the radial striae that characterize the corona and to anomalous relative brightening of locally dense puffs of solar wind that we term "flocculae." We show that these phenomena are inconsistent with smooth radial flow, but consistent with the onset of hydrodynamic or magnetohydrodynamic instabilities leading to a turbulent cascade in the young solar wind.

FADING CORONAL STRUCTURE AND THE ONSET OF TURBULENCE IN THE YOUNG SOLAR WIND

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeForest, C. E.; Matthaeus, W. H.; Viall, N. M.

Above the top of the solar corona, the young, slow solar wind transitions from low- β , magnetically structured flow dominated by radial structures to high- β , less structured flow dominated by hydrodynamics. This transition, long inferred via theory, is readily apparent in the sky region close to 10° from the Sun in processed, background-subtracted solar wind images. We present image sequences collected by the inner Heliospheric Imager instrument on board the Solar-Terrestrial Relations Observatory ( STEREO /HI1) in 2008 December, covering apparent distances from approximately 4° to 24° from the center of the Sun and spanning this transitionmore » in the large-scale morphology of the wind. We describe the observation and novel techniques to extract evolving image structure from the images, and we use those data and techniques to present and quantify the clear textural shift in the apparent structure of the corona and solar wind in this altitude range. We demonstrate that the change in apparent texture is due both to anomalous fading of the radial striae that characterize the corona and to anomalous relative brightening of locally dense puffs of solar wind that we term “flocculae.” We show that these phenomena are inconsistent with smooth radial flow, but consistent with the onset of hydrodynamic or magnetohydrodynamic instabilities leading to a turbulent cascade in the young solar wind.« less

IPS Space Weather Research: Korea-Japan-UCSD

DTIC Science & Technology

2015-04-27

SUBJECT TERMS Solar Physics , Solar Wind, interplanetary scintillation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER...Institution : Center for Astrophysics and space science (CASS), University of California, San Diego (UCSD) - Mailing Address : 9500 Gilman Dr. #0424...the physical parameters like solar wind velocities and densities. This is the one of the unique way to observer the solar wind from the earth. The

CMEs, the Tail of the Solar Wind Magnetic Field Distribution, and 11-yr Cosmic Ray Modulation at 1 AU. Revised

NASA Technical Reports Server (NTRS)

Cliver, E. W.; Ling, A. G.; Richardson, I. G.

2003-01-01

Using a recent classification of the solar wind at 1 AU into its principal components (slow solar wind, high-speed streams, and coronal mass ejections (CMEs) for 1972-2000, we show that the monthly-averaged galactic cosmic ray intensity is anti-correlated with the percentage of time that the Earth is imbedded in CME flows. We suggest that this correlation results primarily from a CME related change in the tail of the distribution function of hourly-averaged values of the solar wind magnetic field (B) between solar minimum and solar maximum. The number of high-B (square proper subset 10 nT) values increases by a factor of approx. 3 from minimum to maximum (from 5% of all hours to 17%), with about two-thirds of this increase due to CMEs. On an hour-to-hour basis, average changes of cosmic ray intensity at Earth become negative for solar wind magnetic field values square proper subset 10 nT.

Magnetic Fields and Flows in Open Magnetic Structures

NASA Technical Reports Server (NTRS)

Jones, Harrlson P.

2004-01-01

Open magnetic structures connect the solar surface to the heliosphere and are thus of great interest in solar-terrestrial physics. This talk is primarily an observational review of what is known about magnetic fields and particularly flows in such regions with special focus on coronal holes and origins of the fast solar wind. First evidence of the connection between these two features was seen in correlations of Skylab data with in situ measurements of the solar wind soon after the discovery of coronal holes, which are now known to emanate from unipolar magnetic regions at the photosphere. Subsequently many observations of have been made, ranging from oscillations in the underlying photosphere and chromosphere, to possible beginnings of the solar wind as observed by Doppler shifts in high chromospheric and transition-region lines, to coronagraphic time-lapse studies of outward-moving blobs of material which perhaps trace elements of solar-wind plasma. Some of the many unresolved and controversial issues regarding details of these observations and their association with the solar wind will be discussed.

Penetration of Solar Wind Driven ULF Waves into the Earth's Inner Magnetosphere: Role in Radiation Belt and Ring Current Dynamics

NASA Astrophysics Data System (ADS)

Mann, Ian; Murphy, Kyle; Rae, Jonathan; Ozeke, Louis; Milling, David

2013-04-01

Ultra-low frequency (ULF) waves in the Pc4-5 band can be excited in the magnetosphere by the solar wind. Much recent work has shown how ULF wave power is strongly correlated with solar wind speed. However, little attention has been paid the dynamics of ULF wave power penetration onto low L-shells in the inner magnetosphere. We use more than a solar cycle of ULF wave data, derived from ground-based magnetometer networks, to examine this ULF wave power penetration and its dependence on solar wind and geomagnetic activity indices. In time domain data, we show very clearly that dayside ULF wave power, spanning more than 4 orders of magnitude, follows solar wind speed variations throughout the whole solar cycle - during periods of sporadic solar maximum ICMEs, during declining phase fast solar wind streams, and at solar minimum, alike. We also show that time domain ULF wave power increases during magnetic storms activations, and significantly demonstrate that a deeper ULF wave power penetration into the inner magnetosphere occurs during larger negative excursions in Dst. We discuss potential explanations for this low-L ULF wave power penetration, including the role of plasma mass density (such as during plasmaspheric erosion), or ring current ion instabilities during near-Earth ring current penetration. Interestingly, we also show that both ULF wave power and SAMPEX MeV electron flux show a remarkable similarity in their penetration to low-L, which suggests that ULF wave power penetration may be important for understanding and explaining radiation belt dynamics. Moreover, the correlation of ULF wave power with Dst, which peaks at one day lag, suggests the ULF waves might also be important for the inward transport of ions into the ring current. Current ring current models, which exclude long period ULF wave transport, under-estimate the ring current during fast solar wind streams which is consistent with a potential role for ULF waves in ring current energisation. The combination of data from ground arrays such as CARISMA and the contemporaneous operation of the NASA Van Allen Probes (VAP) mission offers an excellent basis for understanding this cross-energy plasma coupling which spans more than 6 orders of magnitude in energy. Explaining the casual connections between plasmas in the plasmasphere (eV), ring current (keV), and radiation belt (MeV), via the intermediaries of plasma waves, is key to understanding inner magnetosphere dynamics. This work has received funding from the European Union under the Seventh Framework Programme (FP7-Space) under grant agreement n 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project.

A comparison of solar wind and ionospheric ion acoustic waves

NASA Technical Reports Server (NTRS)

Kintner, P. M.; Kelley, M. C.

1980-01-01

Ion acoustic waves produced during the Trigger experiment are compared to ion acoustic waves observed in the solar wind. After normalizing to the Debye length the spectra are nearly identical, although the ionospheric wave relative energy density is 100 times larger than the solar wind case.