Sample records for ace solar wind

  1. Real-time Kp predictions from ACE real time solar wind

    NASA Astrophysics Data System (ADS)

    Detman, Thomas; Joselyn, Joann

    1999-06-01

    The Advanced Composition Explorer (ACE) spacecraft provides nearly continuous monitoring of solar wind plasma, magnetic fields, and energetic particles from the Sun-Earth L1 Lagrange point upstream of Earth in the solar wind. The Space Environment Center (SEC) in Boulder receives ACE telemetry from a group of international network of tracking stations. One-minute, and 1-hour averages of solar wind speed, density, temperature, and magnetic field components are posted on SEC's World Wide Web page within 3 to 5 minutes after they are measured. The ACE Real Time Solar Wind (RTSW) can be used to provide real-time warnings and short term forecasts of geomagnetic storms based on the (traditional) Kp index. Here, we use historical data to evaluate the performance of the first real-time Kp prediction algorithm to become operational.

  2. 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

  3. 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.

  4. 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.

  5. ACE/SWICS OBSERVATIONS OF HEAVY ION DROPOUTS WITHIN THE SOLAR WIND

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

    Weberg, Micah J.; Zurbuchen, Thomas H.; Lepri, Susan T., E-mail: mjweberg@umich.edu, E-mail: thomasz@umich.edu, E-mail: slepri@umich.edu

    2012-11-20

    We present the first in situ observations of heavy ion dropouts within the slow solar wind, observed for select elements ranging from helium to iron. For iron, these dropouts manifest themselves as depletions of the Fe/H ratio by factors up to {approx}25. The events often exhibit mass-dependent fractionation and are contained in slow, unsteady wind found within a few days from known stream interfaces. We propose that such dropouts are evidence of gravitational settling within large coronal loops, which later undergo interchange reconnection and become source regions of slow, unsteady wind. Previously, spectroscopic studies by Raymond et al. in 1997more » (and later Feldman et al. in 1999) have yielded strong evidence for gravitational settling within these loops. However, their expected in situ signature plasma with heavy elements fractionated by mass was not observed prior to this study. Using data from the SWICS instrument on board the Advanced Composition Explorer (ACE), we investigate the composition of the solar wind within these dropouts and explore long term trends over most of a solar cycle.« less

  6. 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.

  7. 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.

  8. The NOAA Real-Time Solar-Wind (RTSW) System using ACE Data

    NASA Astrophysics Data System (ADS)

    Zwickl, R. D.; Doggett, K. A.; Sahm, S.; Barrett, W. P.; Grubb, R. N.; Detman, T. R.; Raben, V. J.; Smith, C. W.; Riley, P.; Gold, R. E.; Mewaldt, R. A.; Maruyama, T.

    1998-07-01

    The Advanced Composition Explorer (ACE) RTSW system is continuously monitoring the solar wind and produces warnings of impending major geomagnetic activity, up to one hour in advance. Warnings and alerts issued by NOAA allow those with systems sensitive to such activity to take preventative action. The RTSW system gathers solar wind and energetic particle data at high time resolution from four ACE instruments (MAG, SWEPAM, EPAM, and SIS), packs the data into a low-rate bit stream, and broadcasts the data continuously. NASA sends real-time data to NOAA each day when downloading science data. With a combination of dedicated ground stations (CRL in Japan and RAL in Great Britain), and time on existing ground tracking networks (NASA's DSN and the USAF's AFSCN), the RTSW system can receive data 24 hours per day throughout the year. The raw data are immediately sent from the ground station to the Space Environment Center in Boulder, Colorado, processed, and then delivered to its Space Weather Operations center where they are used in daily operations; the data are also delivered to the CRL Regional Warning Center at Hiraiso, Japan, to the USAF 55th Space Weather Squadron, and placed on the World Wide Web. The data are downloaded, processed and dispersed within 5 min from the time they leave ACE. The RTSW system also uses the low-energy energetic particles to warn of approaching interplanetary shocks, and to help monitor the flux of high-energy particles that can produce radiation damage in satellite systems.

  9. 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

  10. A Rigorous Statistical Approach to Determine Solar Wind Composition from ACE/SWICS Data, and New Ne/O Ratios

    NASA Astrophysics Data System (ADS)

    Shearer, P.; Jawed, M. K.; Raines, J. M.; Lepri, S. T.; Gilbert, J. A.; von Steiger, R.; Zurbuchen, T.

    2013-12-01

    The SWICS instruments aboard ACE and Ulysses have performed in situ measurements of individual solar wind ions for a period spanning over two decades. Solar wind composition is determined by accumulating the measurements into an ion count histogram in which each species appears as a distinct peak. Assigning counts to the appropriate species is a challenging statistical problem because of the limited counts for some species and overlap between some peaks. We show that the most commonly used count assignment methods can suffer from significant bias when a highly abundant species overlaps with a much less abundant one. For ACE/SWICS data, this bias results in an overestimated Ne/O ratio. Bias is greatly reduced by switching to a rigorous maximum likelihood count assignment method, resulting in a 30-50% reduction in the estimated Ne abundance. We will discuss the new Ne/O values and put them in context with the solar system abundances for Ne derived from other techniques, such as in situ collection from Genesis and its heritage instrument, the Solar Foil experiment during the Apollo era. The new count assignment method is currently being applied to reanalyze the archived ACE and Ulysses data and obtain revised abundances of C, N, O, Ne, Mg, Si, S, and Fe, leading to revised datasets that will be made publicly available.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. Long Term Missions at the Sun-Earth Libration Point L1: ACE, SOHO, and WIND

    NASA Technical Reports Server (NTRS)

    Roberts, Craig E.

    2011-01-01

    Three heliophysics missions - the Solar Heliospheric Observatory (SOHO), the Advanced Composition Explorer (ACE), and the Global Geoscience WIND - have been orbiting the Sun-Earth interior libration point L1 continuously since 1996, 1997, and 2004, respectively. ACE and WIND (both NASA missions) and SOHO (an ESA-NASA joint mission) are all operated from the NASA Goddard Space Flight Center Flight Dynamics Facility. While ACE and SOHO have been dedicated libration point orbiters since their launches, WIND prior to 2004 flew a remarkable 10-year deep-space trajectory that featured 38 targeted lunar flybys. The L1 orbits and the mission histories of the three spacecraft are briefly reviewed, and the station-keeping techniques and orbit maneuver experience are discussed.

  17. VARIATIONS IN SOLAR WIND FRACTIONATION AS SEEN BY ACE/SWICS AND THE IMPLICATIONS FOR GENESIS MISSION RESULTS

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

    Pilleri, P.; Wiens, R. C.; Reisenfeld, D. B.

    We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999–2001), the solar minimum (2006–2009), and the period in which the Genesis spacecraft was collecting SW (late 2001—early 2004). We differentiate our analysis in terms of SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative tomore » magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variation in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of SW speed, we find a strong correlation, with the remarkable observation that the degree of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances.« less

  18. 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.

  19. A SOAP Web Services Interface to ACE Data

    NASA Astrophysics Data System (ADS)

    Davis, A. J.; Hamell, G. R.

    2005-05-01

    Since early in 1998, NASA's Advanced Composition Explorer (ACE) spacecraft has provided continuous measurements of solar wind and energetic particle activity from L1, located approximately 0.01 AU sunward of Earth. ACE data from nine instruments are being used to measure and compare the elemental and isotopic composition of the solar corona, the nearby interstellar medium, and the Galaxy, and to study particle acceleration processes that occur in a wide range of environments. The spacecraft has enough fuel to stay in orbit about L1 until at least 2020. The ACE Science Center (ASC) provides access to ACE data, and performs level 1 and browse data processing for the science instruments. Available on-line are solar wind, solar energetic particle, and galactic cosmic ray intensity and composition data, as well as solar wind and magnetic field parameters on a variety of time scales. We describe our recent efforts to provide enhanced access to ACE data via a SOAP Web Services interface. The interface utilizes the Space Physics Archive Search and Extract (SPASE) dictionary, and will be compatible with emerging virtual observatories.

  20. Long Term Missions at the Sun-Earth Libration Point L1: ACE, SOHO, and WIND

    NASA Technical Reports Server (NTRS)

    Roberts, Craig E.

    2011-01-01

    Three heliophysics missions -- the Advanced Composition Explorer (ACE), Solar Heliospheric Observatory (SOHO), and the Global Geoscience WIND -- have been orbiting the Sun-Earth interior libration point L1 continuously since 1997, 1996, and 2004, respectively. ACE and WIND (both NASA missions) and SOHO (an ESA-NASA joint mission) are all operated from the NASA Goddard Space Flight Center (GSFC). While ACE and SOHO have been dedicated libration point orbiters since their launches, WIND has had also a remarkable 10-year career flying a deep-space, multiple lunar-flyby trajectory prior to 2004. That era featured 36 targeted lunar flybys with excursions to both L1 and L2 before its final insertion in L1 orbit. A figure depicts the orbits of the three spacecraft, showing projections of the orbits onto the orthographic planes of a solar rotating ecliptic frame of reference. The SOHO orbit is a quasi-periodic halo orbit, where the frequencies of the in-plane and out-of-plane motions are practically equal. Such an orbit is seen to repeat itself with a period of approximately 178 days. For ACE and WIND, the frequencies of the in-plane and out-of-plane motions are unequal, giving rise to the characteristic Lissajous motion. ACE's orbit is of moderately small amplitude, whereas WIND's orbit is a large-amplitude Lissajous of dimensions close to those of the SOHO halo orbit. As motion about the collinear points is inherently unstable, stationkeeping maneuvers are necessary to prevent orbital decay and eventual escape from the L1 region. Though the three spacecraft are dissimilar (SOHO is a 3-axis stabilized Sun pointer, WIND is a spin-stabilized ecliptic pole pointer, and ACE is also spin-stabilized with its spin axis maintained between 4 and 20 degrees of the Sun), the stationkeeping technique for the three is fundamentally the same. The technique consists of correcting the energy of the orbit via a delta-V directed parallel or anti-parallel to the Spacecraft-to-Sun line. SOHO

  1. EVIDENCE FOR NEWLY INITIATED RECONNECTION IN THE SOLAR WIND AT 1 AU

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

    Xu, Xiaojun; Ma, Yonghui; Wong, Hon-Cheng

    2015-08-10

    We report the first evidence for a large-scale reconnection exhaust newly initiated in the solar wind using observations from three spacecraft: ACE, Wind, and ARTEMIS P2. We identified a well-structured X-line exhaust using measurements from ARTEMIS P2 in the downstream solar wind. However, in the upstream solar wind, ACE detected the same current sheet that corresponds to the exhaust identified by ARTEMIS P2 data without showing any reconnection signals. We cannot find any reconnection signals from Wind located between ACE and ARTEMIS P2. Within the exhaust, a magnetic island is identified, which is not consistent with the quasi-steady feature asmore » previously reported and provides further evidence that the reconnection is newly initiated. Our observations show that the entering of energetic particles, probably from Earth's bow shock, makes the crucial difference between the non-reconnecting current sheet and the exhaust. Since no obvious driving factors are responsible for the reconnection initiation, we infer that these energetic particles probably play an important role in the reconnection initiation. Theoretical analysis also shows support for this potential mechanism.« less

  2. 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

  3. Coherence Analysis of the Solar Wind Between l1 and the Lunar Orbit

    NASA Astrophysics Data System (ADS)

    Crane, S. O.; Fuqua, H.; Poppe, A. R.; Harada, Y.; Fatemi, S.; Delory, G. T.

    2016-12-01

    A cross correlation analysis of the lunar and solar wind interaction was performed to understand coherence length scales. This is mandatory for conducting tests in electromagnetic sounding of the moon with two measurement probes. Signal processing and data analysis methods encompass the study of the lunar electromagnetic plasma environment with properties of the solar wind at key positions outside of Earth's magnetosphere. Variations in solar activity detected by ACE, WIND, Kaguya and Lunar Prospector can be informative regarding how well correlated the magnetic properties of the solar wind are between the 1st Lagrange point (ACE & WIND orbits) and the lunar orbit (Kaguya & Lunar Prospector investigations). The analysis objective is to use cross correlation to understand the solar wind coherence between these positions. This requires mastering concrete analysis tools to filter and use data that yields high (>0.80) or intermediate (0.70-0.80) coherence values, while demonstrating an analysis of up to one month of data, and archiving poor (<0.50) cross correlation coefficients for effects of orbit position and downstream distance. We also consider the impact of high energy events such as Coronal Mass Ejections, Solar Flares, and shocks that may be recorded by `ACE's List of Disturbances and Transients' to the effect that, at the current level of analysis, various expected coefficients between 0.55 and 0.85 have been generated for up to 3 months of data, 2008-02-01 through 2008-05-03.

  4. 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.

  5. 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.

  6. The Radial Variation of the Solar Wind Temperature-Speed Relationship

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Generally, the solar wind temperature (T) and speed (V) are well correlated except in Interplanetary Coronal Mass Ejections where this correlation breaks down. We have shown that at 1 AU the speed-temperature relationship is often well represented by a linear fit for a speed range spanning both the slow and fast wind. By examining all of the ACE and OMNI measurements, we found that when coronal holes are large the fast wind can have a different T-V relationship than the slow wind. The best example of this was in 2003 when there was a very large and long-lived outward polarity coronal hole at low latitudes. The long-lived nature of the hole made it possible to clearly distinguish that large holes can have a different T-V relationship. We found it to be rare that holes are large enough and last long enough to have enough data points to clearly demonstrate this effect. In this study we compare the 2003 coronal hole observations from ACE with the Ulysses polar coronal hole measurements. In an even earlier ACE study we found that both the compressions and rarefactions curves are linear, but the compression curve is shifted to higher temperatures. In this presentation we use Helios, Ulysses, and ACE measurements to examine how the T-V relationship varies with distance. The dynamic evolution of the solar wind parameters is revealed when we first separate compressions and rarefactions and then determine the radial profiles of the solar wind parameters. We find that T-V relationship varies with distance and in particular beyond 3 AU the differences between the compressions and rarefactions are quite important and at such distances a simple linear fit does not represent the T-V distribution very well.

  7. Comparative Validation of Realtime Solar Wind Forecasting Using the UCSD Heliospheric Tomography Model

    NASA Technical Reports Server (NTRS)

    MacNeice, Peter; Taktakishvili, Alexandra; Jackson, Bernard; Clover, John; Bisi, Mario; Odstrcil, Dusan

    2011-01-01

    The University of California, San Diego 3D Heliospheric Tomography Model reconstructs the evolution of heliospheric structures, and can make forecasts of solar wind density and velocity up to 72 hours in the future. The latest model version, installed and running in realtime at the Community Coordinated Modeling Center(CCMC), analyzes scintillations of meter wavelength radio point sources recorded by the Solar-Terrestrial Environment Laboratory(STELab) together with realtime measurements of solar wind speed and density recorded by the Advanced Composition Explorer(ACE) Solar Wind Electron Proton Alpha Monitor(SWEPAM).The solution is reconstructed using tomographic techniques and a simple kinematic wind model. Since installation, the CCMC has been recording the model forecasts and comparing them with ACE measurements, and with forecasts made using other heliospheric models hosted by the CCMC. We report the preliminary results of this validation work and comparison with alternative models.

  8. XMM-Newton Observations of Solar Wind Charge Exchange Emission

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    We present an XMM-Newton spectrum of diffuse X-ray emission from within the solar system. The spectrum is dominated by O VII and O VIII lines at 0.57 keV and 0.65 keV, O VIII (and possibly Fe XVII) lines at approximately 0.8 keV, Ne IX lines at approximately 0.92 keV, and Mg XI lines at approximately 1.35 keV. This spectrum is consistent with what is expected from charge exchange emission between the highly ionized solar wind and either interstellar neutrals in the heliosphere or material from Earth's exosphere. The emission is clearly seen as a low-energy ( E less than 1.5 keV) spectral enhancement in one of a series of observations of the Hubble Deep Field North. The X-ray enhancement is concurrent with an enhancement in the solar wind measured by the ACE satellite. The solar wind enhancement reaches a flux level an order of magnitude more intense than typical fluxes at 1 AU, and has ion ratios with significantly enhanced higher ionization states. Whereas observations of the solar wind plasma made at a single point reflect only local conditions which may only be representative of solar wind properties with spatial scales ranging from less than half of an Earth radii (approximately 10 s) to 100 Earth radii, X-ray observations of solar wind charge exchange are remote sensing measurements which may provide observations which are significantly more global in character. Besides being of interest in its own right for studies of the solar system, this emission can have significant consequences for observations of more cosmological objects. It can provide emission lines at zero redshift which are of particular interest (e.g., O VII and O VIII) in studies of diffuse thermal emission, and which can therefore act as contamination in objects which cover the entire detector field of view. We propose the use of solar wind monitoring data, such as from the ACE and Wind spacecraft, as a diagnostic to screen for such possibilities.

  9. 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.

  10. Studying Solar Wind Properties Around CIRs and Their Effects on GCR Modulation

    NASA Astrophysics Data System (ADS)

    Ghanbari, K.; Florinski, V. A.

    2017-12-01

    Corotating interaction region (CIR) events occur when a fast solar wind stream overtakes slow solar wind, forming a compression region ahead and a rarefaction region behind in the fast solar wind. Usually this phenomena occurs along with a crossing of heliospheric current sheet which is the surface separating solar magnetic fields of opposing polarities. In this work, the solar plasma data provided by the ACE science center are utilized to do a superposed epoch analysis on solar parameters including proton density, proton temperature, solar wind speed and solar magnetic field in order to study how the variations of these parameters affect the modulation of galactic cosmic rays. Magnetic fluctuation variances in different parts a of CIR are computed and analyzed using similar techniques in order to understand the cosmic-ray diffusive transport in these regions.

  11. Solar wind modulation of UK lightning

    NASA Astrophysics Data System (ADS)

    Davis, Chris; Harrison, Giles; Lockwood, Mike; Owens, Mathew; Barnard, Luke

    2013-04-01

    The response of lightning rates in the UK to arrival of high speed solar wind streams at Earth is investigated using a superposed epoch analysis. The fast solar wind streams' arrivals are determined from modulation of the solar wind Vy component, measured by the Advanced Composition Explorer (ACE) spacecraft. Lightning rate changes around these event times are then determined from the very low frequency Arrival Time Difference (ATD) system of the UK Met Office. Arrival of high speed streams at Earth is found to be preceded by a decrease in total solar irradiance and an increase in sunspot number and Mg II emissions. These are consistent with the high speed stream's source being co-located with an active region appearing on the Eastern solar limb and rotating at the 27 day rate of the Sun. Arrival of the high speed stream at Earth also coincides with a rapid decrease in cosmic ray flux and an increase in lightning rates over the UK, persisting for around 40 days. The lightning rate increase is corroborated by an increase in the total number of thunder days observed by UK Met stations, again for around 40 days after the arrival of a high speed solar wind stream. This increase in lightning may be beneficial to medium range forecasting of hazardous weather.

  12. Periodic Alpha Signatures and the Origins of the Slow Solar Wind

    NASA Astrophysics Data System (ADS)

    Blume, Catherine; Kepko, Larry

    2017-01-01

    The origin of the slow solar wind has puzzled scientists for decades. Both flux tube geometry of field lines open to the heliosphere and magnetic reconnection that opens field lines that were previously closed to the heliosphere have been proposed as explanations (via the expansion factor and S-web models, respectively), but the observations to date have proven an inadequate test for distinguishing between the theories. However, short term (~hours) variability of alpha particles could provide the set of observations that tips the balance. Alpha particles compose about 4% of the solar wind, and its precise composition is determined by dynamics in the solar atmosphere. Therefore, compositional changes in the alpha to proton ratio must have originated at the Sun, making alphs tracer particles of sorts and carrying signatures of their solar creation. We examined in situ alpha density and proton density data from the Wind, ACE, STEREO-B, AND STEREO-A spacecraft, focusing on a pseudostreamer that occurred August 9, 2008. This case study found one clear periodic structure in the slow solar wind preceding the pseudostreamer in Wind/ACE and the same periodic structure in the in situ data at STEREO-B. The existence of this slow wind structure in association with a pseudostreamer directly contradicts the expansion factor model, which predicts that pseudostreamers produce fast wind. The structure's appearance at STEREO-B, which was located 30 degrees behind the Earth-Sun line, further indicates that the mechanism at the Sun is responsible for its formation was active for at least three days. Moreover, an analysis of both helmet streamer and pseudostreamer events between 2007-2009 finds that similar density structures exist in at least 35% of all streamers. This indicates that the same physical process that produces this slow solar wind occurs with a degree of frequency in association with both types of streamers. The clarity, duration, and frequency of these periodic density

  13. 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.

  14. The solar array is installed on ACE in SAEF-2

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Applied Physics Laboratory engineers and technicians from Johns Hopkins University assist in guiding the Advanced Composition Explorer (ACE) as it is hoisted over a platform for solar array installation in KSC's Spacecraft Assembly and Encapsulation Facility-II. Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 25, ACE will study low-energy particles of solar origin and high-energy galactic particles. The ACE observatory will contribute to the understanding of the formation and evolution of the solar system as well as the astrophysical processes involved. The collecting power of instruments aboard ACE is 10 to 1,000 times greater than anything previously flown to collect similar data by NASA.

  15. Detection of oppositely directed reconnection jets in a solar wind current sheet

    NASA Astrophysics Data System (ADS)

    Davis, M. S.; Phan, T. D.; Gosling, J. T.; Skoug, R. M.

    2006-10-01

    We report the first two-spacecraft (Wind and ACE) detection of oppositely directed plasma jets within a bifurcated current sheet in the solar wind. The event occurred on January 3, 2003 and provides further direct evidence that such jets result from reconnection. The magnetic shear across the bifurcated current sheet at both Wind and ACE was ~150°, indicating that the magnetic shear must have been the same at the reconnection site located between the two spacecraft. These observations thus provide strong evidence for component merging with a guide field ~ 30% of the antiparallel field. The dimensionless reconnection rate based on the measured inflow was 0.03, implying fast reconnection.

  16. 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.

  17. The solar array is installed on ACE in SAEF-2

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Applied Physics Laboratory engineers and technicians from Johns Hopkins University install solar array panels on the Advanced Composition Explorer (ACE) in KSC's Spacecraft Assembly and Encapsulation Facility-II. The panel on which they are working is identical to the panel (one of four) seen in the foreground on the ACE spacecraft. Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 25, ACE will study low- energy particles of solar origin and high-energy galactic particles for a better understanding of the formation and evolution of the solar system as well as the astrophysical processes involved. The ACE observatory will be placed into an orbit almost a million miles (1.5 million kilometers) away from the Earth, about 1/100 the distance from the Earth to the Sun. The collecting power of instrumentation aboard ACE is at least 100 times more sensitive than anything previously flown to collect similar data by NASA.

  18. 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.

  19. Detection of oppositely directed reconnection jets in a solar wind current sheet

    NASA Astrophysics Data System (ADS)

    Davis, M. S.; Phan, T. D.; Gosling, J. T.; Skoug, R. M.

    2006-12-01

    We report the first two-spacecraft (Wind and ACE) detection of oppositely directed plasma jets within a bifurcated current sheet in the solar wind. The event occurred on January 3, 2003 and provides further direct evidence that such jets result from reconnection. The magnetic shear across the bifurcated current sheet at both Wind and ACE was approximately 150 degrees, indicating that the magnetic shear must have been the same at the reconnection site located between the two spacecraft. These observations thus provide strong evidence for component merging with a guide field approximately 30% of the antiparallel field. The dimensionless reconnection rate based on the measured inflow was 0.03, implying fast reconnection.

  20. 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

    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

  1. The solar array is installed on ACE in SAEF-2

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Applied Physics Laboratory Engineer Cliff Willey (kneeling) and Engineering Assistant Jim Hutcheson from Johns Hopkins University install solar array panels on the Advanced Composition Explorer (ACE) in KSC's Spacecraft Assembly and Encapsulation Facility-II. Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 25, ACE will study low-energy particles of solar origin and high-energy galactic particles for a better understanding of the formation and evolution of the solar system as well as the astrophysical processes involved. The ACE observatory will be placed into an orbit almost a million miles (1.5 million kilometers) away from the Earth, about 1/100 the distance from the Earth to the Sun. The collecting power of instrumentation aboard ACE is at least 100 times more sensitive than anything previously flown to collect similar data by NASA.

  2. Direct evidence for magnetic reconnection in the solar wind near 1 AU

    NASA Astrophysics Data System (ADS)

    Gosling, J. T.; Skoug, R. M.; McComas, D. J.; Smith, C. W.

    2005-01-01

    We have obtained direct evidence for local magnetic reconnection in the solar wind using solar wind plasma and magnetic field data obtained by the Advanced Composition Explorer (ACE). The prime evidence consists of accelerated ion flow observed within magnetic field reversal regions in the solar wind. Here we report such observations obtained in the interior of an interplanetary coronal mass ejection (ICME) or at the interface between two ICMEs on 23 November 1997 at a time when the magnetic field was stronger than usual. The observed plasma acceleration was consistent with the Walen relationship, which relates changes in flow velocity to density-weighted changes in the magnetic field vector. Pairs of proton beams having comparable densities and counterstreaming relative to one another along the magnetic field at a speed of ˜1.4VA, where VA was the local Alfven speed, were observed near the center of the accelerated flow event. We infer from the observations that quasi-stationary reconnection occurred sunward of the spacecraft and that the accelerated flow occurred within a Petschek-type reconnection exhaust region bounded by Alfven waves and having a cross section width of ˜4 × 105 km as it swept over ACE. The counterstreaming ion beams resulted from solar wind plasma entering the exhaust region from opposite directions along the reconnected magnetic field lines. We have identified a limited number (five) of other accelerated flow events in the ACE data that are remarkably similar to the 23 November 1997 event. All such events identified occurred at thin current sheets associated with moderate to large changes in magnetic field orientation (98°-162°) in plasmas characterized by low proton beta (0.01-0.15) and high Alfven speed (51-204 km/s). They also were all associated with ICMEs.

  3. Extension of the ACE solar panels is tested in SAEF-II

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Extension of the solar panels is tested on the Advanced Composition Explorer (ACE) spacecraft in KSC's Spacecraft Assembly and Encapsulation Facility-II (SAEF-II). Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 25, ACE will study low-energy particles of solar origin and high-energy galactic particles. The collecting power of instruments aboard ACE is 10 to 1,000 times greater than anything previously flown to collect similar data by NASA.

  4. A Solar Wind Source Tracking Concept for Inner Heliosphere Constellations of Spacecraft

    NASA Astrophysics Data System (ADS)

    Luhmann, J. G.; Li, Yan; Arge, C. N.; Hoeksema, Todd; Zhao, Xuepu

    2003-09-01

    During the next decade, a number of spacecraft carrying in-situ particles and fields instruments, including the twin STEREO spacecraft, ACE, WIND, and possibly Triana, will be monitoring the solar wind in the inner heliosphere. At the same time, several suitably instrumented planetary missions, including Nozomi, Mars Express, and Messenger will be in either their cruise or orbital phases which expose them at times to interplanetary conditions and/or regions affected by the solar wind interaction. In addition to the mutual support role for the individual missions that can be gained from this coincidence, this set provides an opportunity for evaluating the challenges and tools for a future targeted heliospheric constellation mission. In the past few years the capability of estimating the solar sources of the local solar wind has improved, in part due to the ability to monitor the full-disk magnetic field of the Sun on an almost continuous basis. We illustrate a concept for a model and web-based display that routinely updates the estimated sources of the solar wind arriving at inner heliospheric spacecraft.

  5. Identifying Wave-Particle Interactions in the Solar Wind using Statistical Correlations

    NASA Astrophysics Data System (ADS)

    Broiles, T. W.; Jian, L. K.; Gary, S. P.; Lepri, S. T.; Stevens, M. L.

    2017-12-01

    Heavy ions are a trace component of the solar wind, which can resonate with plasma waves, causing heating and acceleration relative to the bulk plasma. While wave-particle interactions are generally accepted as the cause of heavy ion heating and acceleration, observations to constrain the physics are lacking. In this work, we statistically link specific wave modes to heavy ion heating and acceleration. We have computed the Fast Fourier Transform (FFT) of transverse and compressional magnetic waves between 0 and 5.5 Hz using 9 days of ACE and Wind Magnetometer data. The FFTs are averaged over plasma measurement cycles to compute statistical correlations between magnetic wave power at each discrete frequency, and ion kinetic properties measured by ACE/SWICS and Wind/SWE. The results show that lower frequency transverse oscillations (< 0.2 Hz) and higher frequency compressional oscillations (> 0.4 Hz) are positively correlated with enhancements in the heavy ion thermal and drift speeds. Moreover, the correlation results for the He2+ and O6+ were similar on most days. The correlations were often weak, but most days had some frequencies that correlated with statistical significance. This work suggests that the solar wind heavy ions are possibly being heated and accelerated by both transverse and compressional waves at different frequencies.

  6. Diamagnetic effect in the foremoon solar wind observed by Kaguya

    NASA Astrophysics Data System (ADS)

    Nishino, M. N.; Saito, Y.; Tsunakawa, H.; Miyake, Y.; Harada, Y.; Yokota, S.; Takahashi, F.; Matsushima, M.; Shibuya, H.; Shimizu, H.

    2016-12-01

    Interaction between the lunar surface and incident solar wind is one of the crucial phenomena of the lunar plasma sciences. Recent observations by lunar orbiters revealed that strength of the interplanetary magnetic field (IMF) at spacecraft altitude increases over crustal magnetic fields on the dayside. In addition, variations of the IMF on the lunar night side have been reported in the viewpoint of diamagnetic effect around the lunar wake. However, few studies have been performed for the IMF over non-magnetized regions on the dayside. Here we show an event where strength of the IMF decreases at 100 km altitude on the lunar dayside (i.e. in the foremoon solar wind) when the IMF is almost parallel to the incident solar wind flow, comparing the upstream solar wind data from ACE and WIND with Kaguya magnetometer data. The lunar surface below the Kaguya orbit is not magnetized (or very weakly magnetized), and the sunward-travelling protons show signatures of those back-scattered at the lunar surface. We find that the decrease in the magnetic pressure is compensated by the thermal pressure of the back-scattered protons. In other words, the IMF strength in the foremoon solar wind decreases by diamagnetic effect of sunward-travelling protons back-scattered at the lunar dayside surface. Such diamagnetic effect would be prominent in the high-beta solar wind environment, and may be ubiquitous in the environment where planetary surface directly interacts with surrounding space plasma.

  7. Diamagnetic effect in the foremoon solar wind observed by Kaguya

    NASA Astrophysics Data System (ADS)

    Nishino, Masaki N.; Saito, Yoshifumi; Tsunakawa, Hideo; Miyake, Yohei; Harada, Yuki; Yokota, Shoichiro; Takahashi, Futoshi; Matsushima, Masaki; Shibuya, Hidetoshi; Shimizu, Hisayoshi

    2017-04-01

    Direct interaction between the lunar surface and incident solar wind is one of the crucial phenomena of the planetary plasma sciences. Recent observations by lunar orbiters revealed that strength of the interplanetary magnetic field (IMF) at spacecraft altitude often increases over crustal magnetic fields on the dayside. In addition, variations of the IMF on the lunar night side have been reported in the viewpoint of diamagnetic effect around the lunar wake. However, few studies have been performed for the IMF over non-magnetized regions on the dayside. Here we show an event where strength of the IMF decreases at 100 km altitude on the lunar dayside (i.e. in the foremoon solar wind) when the IMF is almost parallel to the incident solar wind flow, comparing the upstream solar wind data from ACE with Kaguya magnetometer data. The lunar surface below the Kaguya orbit is not magnetized (or very weakly magnetized), and the sunward-travelling protons show signatures of those back-scattered at the lunar surface. We find that the decrease in the magnetic pressure is compensated by the thermal pressure of the back-scattered protons. In other words, the IMF strength in the foremoon solar wind decreases by diamagnetic effect of sunward-travelling protons back-scattered at the lunar dayside surface. Such an effect would be prominent in the high-beta solar wind, and may be ubiquitous in the environment where planetary surface directly interacts with surrounding space plasma.

  8. 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.

  9. Lessons Learned from 10 Years of STEREO Solar Wind Observations

    NASA Astrophysics Data System (ADS)

    Jian, L. K.; Russell, C. T.; Luhmann, J. G.; Galvin, A. B.

    2017-12-01

    We have conducted long-term observations of large-scale solar wind structures since the launch of STEREO spacecraft, specifically interplanetary CMEs (ICMEs), slow-to-fast stream interaction regions (SIRs), and interplanetary shocks. In combination with our previous observations of the same solar wind structures in 1995-2009 using Wind/ACE data and the same identification criteria, we have first studied the solar cycle variations of these structures, especially for the same phases of solar cycles 23 and 24. Attributing the shocks to the interplanetary drivers, we have statistically compared the shocks driven by ICMEs and SIRs, and explained the shocks without a clear local driver. In addition, using the longitudinal and latitudinal separations between the twin spacecraft, we have investigated the recurrence and variability of ICMEs and SIRs, and gained the critical implications for the proposed L5 mission. At last, we have associated the heliospheric current sheet (HCS) crossings with the ICMEs and SIRs, and compared the properties of SIRs with and without HCS crossings, which correspond to the helmet streamers and pseudostreamers, respectively. The findings are important constraints on the theories of slow wind origin.

  10. Sources of the solar wind - the heliospheric point of view

    NASA Astrophysics Data System (ADS)

    Von Steiger, Rudolf; Shearer, Paul; Zurbuchen, Thomas

    The solar wind as observed in the heliosphere has several properties that can be interpreted as signatures of conditions and processes at its source in the solar atmosphere. Traditionally it has been customary to distinguish between solar wind types solely based on its speed, "fast" and "slow" wind. Over the last couple of decades new instruments resolving not only the main constituents (protons and alpha particles) but also heavy ions from C to Fe have added new observables, in particular the charge state and elemental composition of these ions. The charge states are indicators of the coronal temperature at the source region; they have confirmed that the "fast" wind emanates from the relatively cool coronal hole regions, while the "slow" wind originates from hotter sources such as the streamer belt and active regions. Thus they are more reliable indicators of solar wind source than the speed alone could be because they readily discriminate between "fast" wind from coronal holes and fast coronal mass ejections (CMEs). The elemental composition in the solar wind compared to the abundances in the photosphere shows a typical fractionation that depends on the first ionization potential (FIP) of the elements. Since that fractionation occurs beneath the corona, in the chromosphere, its strength is indicative of the conditions in that layer. While the "fast" wind is very similar to photospheric composition, the fractionation of the "slow" wind and of CMEs is higher and strongly variable. We will review the observations of the SWICS composition instruments on both the ACE and the Ulysses missions, which have made composition observations between 1 and 5 AU and at all latitudes in the heliosphere over the last two decades. Specifically, analysis of the "slow" wind observations at all time scales, from hours to complete solar cycles, will be used to better characterize its source regions.

  11. 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.

  12. Forecast and Specification of Radiation Belt Electrons Based on Solar Wind Measurements

    NASA Astrophysics Data System (ADS)

    Li, X.; Barker, A.; Burin Des Roziers, E.

    2003-12-01

    Relativistic electrons in the Earth's magnetosphere are of considerable practical importance because of their effect on spacecraft and because of their radiation hazard to astronauts who perform extravehicular activity. The good correlation between solar wind velocity and MeV electron fluxes at geosynchronous orbit has long been established. We have developed a radial diffusion model, using solar wind parameters as the only input, to reproduce the variation of the MeV electrons at geosynchronous orbit. Based on this model, we have constructed a real-time model that forecasts one to two days in advance the daily averaged >2 MeV electron flux at geosynchronous orbit using real-time solar wind data from ACE. The forecasts from this model are available on the web in real time. A natural extension of our current model is to create a system for making quantitative forecasts and specifications of radiation belt electrons at different radial distances and different local times based on the solar wind conditions. The successes and obstacles associated with this extension will be discussed in this presentation.

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

    NASA Astrophysics Data System (ADS)

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

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

  14. ICME Identification from Solar Wind Ion Measurements

    NASA Astrophysics Data System (ADS)

    Shinde, A.; Russell, C. T.

    2002-12-01

    In the solar corona, coronal mass ejections are generally identified as an outward moving density enhancement. At 1AU their interplanetary counterparts are generally identified as a twisted and enhanced magnetic structures lasting of the order of a day. In an effort to better classify ICMEs we attempt herein to identify their start and stop time by their signatures in ion data obtained by Wind and ACE solar wind instruments. We search for periods in which the solar wind speed is linearly decreasing and the ion temperature is cool, with a thermal speed of less than 20 km/s. We required a simultaneous enhanced magnetic field but required no special signature of this enhancement. We compared these identifications with those made by D. Larson and R. P. Lepping and published on the web. Of 14 events, 4 were not identified as ICMEs by either Larson or Lepping. Similarly they identified many events that we did not, often because the ion temperature was above our classification threshold, but also because there was no clear speed decrease as the event crossed the spacecraft as would signal an expanding structure. The best events in Larson and Lepping's list had a rate of speed decrease that, if due to the expansion of the structure with distance from the sun moving at the average observed speed, would bring the structure from zero width to the present size in its calculated transit time. We conclude that cold ion temperatures and a declining solar wind velocity are frequent ICME signatures but are neither necessary nor sufficient for ICME identification.

  15. Space Weather Drivers in the ACE Era

    NASA Astrophysics Data System (ADS)

    Vogt, M.; Puhl-Quinn, P.; Jordanova, V. K.; Smith, C. W.; Cohen, C. M.

    2004-12-01

    The Advanced Composition Explorer (ACE) spacecraft was launched Aug.~25, 1997 [Stone et al., 1998]. Beginning shortly after launch and continuing to the present day ACE has provided real-time data telemetry of solar wind conditions upstream of the Earth. The real-time data includes solar wind speed and density, magnetic field direction and magnitude, and a range of energetic particle intensities [Zwickl et al., 1999]. The real-time data product is provided within 5 minutes of observation and many partners from both industry and science use these data for a variety of purposes. The most common purpose of practical industrial application involves mitigation of lost services arising from magnetospheric storm activity. Many space weather efforts are directed at providing improved predictions of magnetospheric response that can be applied to real-time data in the hope of better predicting the vulnerability and required action of industry to approaching disturbances. It therefore seems prudent that following 6 years of activity including one solar maximum period we should evaluate the nature and strength of the largest disturbances observed with the hope of better assessing the industrial response. Simply put: ``Did ACE observe disturbances that were as large as those seen previously during the space age?'' If not, it may be the case that industry must evaluate its response to the real-time warnings and not become complacent by the simple act of survival. We compare the most intense space weather events of the ACE era with those recorded on the Omnitape data set spanning 40+ years of spacecraft measurements in the near-Earth environment. We compare both magnetospheric response parameters and solar wind drivers. In addition, we compare the large energetic particle events over the same time frame. Stone, E.~C., et al., Space Science Rev., 86(1-4), 357-408, 1998. Zwickl, R.~D., et al., Space Science Rev., 86(1-4), 633-648, 1998.

  16. 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.

  17. Kinetic Properties of Solar Wind Silicon and Iron Ions

    NASA Astrophysics Data System (ADS)

    Janitzek, N. P.; Berger, L.; Drews, C.; Wimmer-Schweingruber, R. F.

    2017-12-01

    Heavy ions with atomic numbers Z>2 account for less than one percent of the solar wind ions. However, serving as test particles with differing mass and charge, they provide a unique experimental approach to major questions of solar and fundamental plasma physics such as coronal heating, the origin and acceleration of the solar wind and wave-particle interaction in magnetized plasma. Yet the low relative abundances of the heavy ions pose substantial challenges to the instrumentation measuring these species with reliable statistics and sufficient time resolution. As a consequence the numbers of independent measurements and studies are small. The Charge Time-Of-Flight (CTOF) mass spectrometer as part of the Charge, ELement and Isotope Analysis System (CELIAS) onboard the SOlar and Heliospheric Observatory (SOHO) is a linear time-of-flight mass spectrometer which was operated at Lagrangian point L1 in 1996 for a few months only, before it suffered an instrument failure. Despite its short operation time, the CTOF sensor measured solar wind heavy ions with excellent charge state separation, an unprecedented cadence of 5 minutes and very high counting statistics, exceeding similar state-of-the-art instruments by a factor of ten. In contrast to earlier CTOF studies which were based on reduced onboard post-processed data, in our current studies we use raw Pulse Height Analysis (PHA) data providing a significantly increased mass, mass-per-charge and velocity resolution. Focussing on silicon and iron ion measurements, we present an overview of our findings on (1) short time behavior of heavy ion 1D radial velocity distribution functions, (2) differential streaming between heavy ions and solar wind bulk protons, (3) kinetic temperatures of heavy ions. Finally, we compare the CTOF results with measurements of the Solar Wind Ion Composition Spectrometer (SWICS) instrument onboard the Advanced Composition Explorer (ACE).

  18. 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.

  19. Coronal hole evolution from multi-viewpoint data as input for a STEREO solar wind speed persistence model

    NASA Astrophysics Data System (ADS)

    Temmer, Manuela; Hinterreiter, Jürgen; Reiss, Martin A.

    2018-03-01

    We present a concept study of a solar wind forecasting method for Earth, based on persistence modeling from STEREO in situ measurements combined with multi-viewpoint EUV observational data. By comparing the fractional areas of coronal holes (CHs) extracted from EUV data of STEREO and SoHO/SDO, we perform an uncertainty assessment derived from changes in the CHs and apply those changes to the predicted solar wind speed profile at 1 AU. We evaluate the method for the time period 2008-2012, and compare the results to a persistence model based on ACE in situ measurements and to the STEREO persistence model without implementing the information on CH evolution. Compared to an ACE based persistence model, the performance of the STEREO persistence model which takes into account the evolution of CHs, is able to increase the number of correctly predicted high-speed streams by about 12%, and to decrease the number of missed streams by about 23%, and the number of false alarms by about 19%. However, the added information on CH evolution is not able to deliver more accurate speed values for the forecast than using the STEREO persistence model without CH information which performs better than an ACE based persistence model. Investigating the CH evolution between STEREO and Earth view for varying separation angles over ˜25-140° East of Earth, we derive some relation between expanding CHs and increasing solar wind speed, but a less clear relation for decaying CHs and decreasing solar wind speed. This fact most likely prevents the method from making more precise forecasts. The obtained results support a future L5 mission and show the importance and valuable contribution using multi-viewpoint data.

  20. The spatial gradients in the solar wind and IMF in the vicinity of the first Lagrangian point

    NASA Astrophysics Data System (ADS)

    Lai, H.; Russell, C. T.; Riley, P.

    2017-12-01

    To verify the accuracy of predicted solar wind conditions at L1, we need to know how accurate our measurements are as well as the spatial gradients of solar wind properties since the data are not obtained precisely at the L1 point. With ACE, Wind, and DSCOVR currently taking measurements in the vicinity of L1, we first need to test whether their responses to the solar wind are the same and if not, to determine which data are most accurate. Secondly, we need to study the coherency scales of the solar wind properties, which determine the scale over which the measurements can be accurately extrapolated. By comparing the measurements during large solar wind structures (e.g. CMEs), we find that the magnetic fields from all spacecraft are measured accurately, but the plasma parameters can be significantly different from one spacecraft to another. By examining the sum of magnetic and plasma thermal pressure across tangential discontinuities, we find that the density and temperature measurements from Wind and DSCOVR do show pressure continuity as expected while ACE does not. Since plasma data from DSCOVR have a greater variability about the mean and have many data gaps, we believe that data from Wind should be used whenever available. We find that strength of the magnetic field and zero levels of the various magnetometers are consistent, but the direction of the magnetic field can change significantly in the cross-flow direction. Thus, over the separation distance of spacecraft near L1, large changes in the IMF direction can appear between spacecraft even though the IMF is accurately measured. In contrast, the plasma parameters, when measured accurately, are spatially uniform over about 100Re and may be extrapolated well. Our results can also be applied to improving future space weather mission design. A constellation of cubesats with magnetometers would be needed to determine the IMF impinging on the magnetosphere. Fewer plasma instruments are needed to determine the

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

    NASA Technical Reports Server (NTRS)

    Riley, Peter

    1999-01-01

    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 analyzed a series of low density intervals in the ACE (Advanced Composition Explorer) plasma data set that bear many similarities to CMEs. We have begun a series of 3D, MHD (Magnetohydrodynamics) coronal models to probe potential causes of these events. We also edited two manuscripts concerning the properties of CMEs in the solar wind. One was re-submitted to the Journal of Geophysical Research.

  2. Influence of Convective Effect of Solar Winds on the CME Transit Time

    NASA Astrophysics Data System (ADS)

    Sun, Lu-yuan

    2017-10-01

    Based on an empirical model for predicting the transit time of coronal mass ejections (CMEs) proposed by Gopalswamy, 52 CME events which are related to the geomagnetic storms of Dst < -50 nT, and 10 CME events which caused extremely strong geomagnetic storms (Dst < -200 nT) in 1996- 2007 are selected, and combined with the observational data of the interplanetary solar winds that collected by the ACE satellite at 1AU, to analyze the influence of convective effect of ambient solar winds on the prediction of the CME transit time when it arrives at a place of 1 AU. After taking the convective effect of ambient solar winds into account, the standard deviation of predictions is reduced from 16.5 to 11.4 hours for the 52 CME events, and the prediction error is less than 15 hours for 68% of these events; while the standard deviation of predictions is reduced from 10.6 to 6.5 hours for the 10 CME events that caused extremely strong geomagnetic storms, and the prediction error is less than 5 hours for 6 of the 10 events. These results show that taking the convective effect of ambient solar winds into account can reduce the standard deviation of the predicted CME transit time, hence the convective effect of solar winds plays an important role for predicting the transit times of CME events.

  3. 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

  4. Combining Remote and In Situ Observations with MHD models to Understand the Formation of the Slow Solar Wind

    NASA Astrophysics Data System (ADS)

    Viall, N. M.; Kepko, L.; Antiochos, S. K.; Lepri, S. T.; Vourlidas, A.; Linker, J.

    2017-12-01

    Connecting the structure and variability in the solar corona to the Heliosphere and solar wind is one of the main goals of Heliophysics and space weather research. The instrumentation and viewpoints of the Parker Solar Probe and Solar Orbiter missions will provide an unprecedented opportunity to combine remote sensing with in situ data to determine how the corona drives the Heliosphere, especially as it relates to the origin of the slow solar wind. We present analysis of STEREO coronagraph and heliospheric imager observations and of in situ ACE and Wind measurements that reveal an important connection between the dynamics of the corona and of the solar wind. We show observations of quasi-periodic release of plasma into the slow solar wind occurring throughout the corona - including regions away from the helmet streamer and heliospheric current sheet - and demonstrate that these observations place severe constraints on the origin of the slow solar wind. We build a comprehensive picture of the dynamic evolution by combining remote imaging data, in situ composition and magnetic connectivity information, and MHD models of the solar wind. Our results have critical implications for the magnetic topology involved in slow solar wind formation and magnetic reconnection dynamics. Crucially, this analysis pushes the limits of current instrument resolution and sensitivity, showing the enormous potential science to be accomplished with the Parker Solar Probe and Solar Orbiter missions.

  5. The Delta II with ACE aboard is prepared for liftoff from Pad 17A, CCAS

    NASA Technical Reports Server (NTRS)

    1997-01-01

    After launch tower retraction, the Boeing Delta II expendable launch vehicle carrying the Advanced Composition Explorer (ACE) undergoes final preparations for liftoff in the predawn hours of Aug. 24, 1997, at Launch Complex 17A, Cape Canaveral Air Station. This is the second Delta launch under the Boeing name and the first from Cape Canaveral. ACE with its combination of nine sensors and instruments will investigate the origin and evolution of solar phenomenon, the formation of solar corona, solar flares and acceleration of the solar wind. ACE was built for NASA by the Johns Hopkins Applied Physics Laboratory and is managed by the Explorer Project Office at NASA's Goddard Space Flight Center. The lead scientific institution is the California Institute of Technology.

  6. Solar Wind drivers affecting GIC magnitude in New Zealand.

    NASA Astrophysics Data System (ADS)

    Mac Manus, D. H.; Rodger, C. J.; Dalzell, M.; Petersen, T.; Clilverd, M. A.

    2017-12-01

    Interplanetary shocks arriving at the Earth drive magnetosphere and ionosphere current systems. Ground based magnetometers detect the time derivation of the horizontal magnetic field (dBH/dt) which can indicate the strength of these ionospheric currents. The strong dBH/dt spikes have been observed to cause large Geomagnetically Induced Currents (GIC) in New Zealand. Such could, potentially lead to large scale damage to technological infrastructure such as power network transformers; one transformer was written off in New Zealand after a sudden commencement on 6 November 2001. The strength of the incoming interplanetary shocks are monitored by satellite measurements undertaken at the L1 point. Such measurements could give power network operators a 20-60 minute warning before potentially damaging GIC occurs. In this presentation we examine solar wind measurements from the Advanced Composition Explorer (ACE), Wind, and the Solar and Heliospheric Observatory (SOHO). We contrast those solar wind observations with GIC measured in New Zealand's South Island from 2001 to 2016. We are searching for a consistent relationship between the incoming interplanetary shock and the GIC magnitude. Such a relationship would allow Transpower New Zealand Limited a small time window to implement mitigation plans in order to restrict any GIC-caused damage.

  7. Constraining heating processes in the solar wind with kinetic properties of heavy ions

    NASA Astrophysics Data System (ADS)

    Kasper, J. C.; Tracy, P.; Zurbuchen, T.; Raines, J. M.; Gilbert, J. A.; Shearer, P.

    2016-12-01

    Heavy ion components (A > 4 amu) in collisionally young solar wind plasma show a clear, stable dependence of temperature on mass, probably reflecting the conditions in the solar corona. Using results from the Solar Wind Ion Composition Spectrometer (SWICS) onboard the Advanced Composition Explorer (ACE), we find that the heavy ion temperatures are well organized by a simple linear fit of the form Ti/Tp=(1.35+/- .02) mi/mp. Most importantly we find that the current model predictions based on turbulent transport and kinetic dissipation are in agreement with observed nonthermal heating in intermediate collisional age plasma for m/q < 3.5 amu/e, but are not in quantitative or qualitative agreement with the lowest collisional age results. These dependencies provide new constraints on the physics of ion heating in multispecies plasma, along with predictions to be tested by the upcoming Solar Probe Plus and Solar Orbiter missions to the near-Sun environment.

  8. 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

  9. Measurements of Heavy Ion Differential Streaming with SOHO/CELIAS/CTOF and ACE/SWICS at 1 AU

    NASA Astrophysics Data System (ADS)

    Janitzek, Nils; Berger, Lars; Taut, Andreas; Drews, Christian; Wimmer-Schweingruber, Robert

    2016-04-01

    Helios measurements in the early 1980s showed the existence of a systematic velocity difference, called "differential streaming", between solar wind bulk protons and alpha particles with the alphas streaming faster than the protons. The absolute differential speed between these species decreases with radial distance to the Sun and decreasing proton speed. In the fast wind it was measured to be approximately half of the local Alfvén speed. However, the detailed processes of acceleration and regulation of differential streaming are still not well understood. A proposed key process is resonant wave particle interaction between the ions and Alfvén waves near the ion-cyclotron frequency which is able to accelerate the alphas preferentially due to their higher mass-per-charge ratio. Measuring the differential speed of a wide set of solar wind heavy ions and therefore extending the mass-per-charge range significantly can provide additional information on the underlying processes that we cannot infer from the alphas and protons alone. We analysed data measured at L1 by SOHO/CELIAS/CTOF in 1996 and ACE/SWICS from 2001 to 2010. Both instruments are linear time-of-flight mass spectrometers which measure the ions' radial 1D velocity distributions with a cadence of 5 and 12 minutes, respectively. Comparing the mean ion speed, with the mean proton speed measured routinely by the SOHO/CELIAS/MTOF/PM and ACE/SWEPAM, respectively, we obtain the differential streaming for major charge states of solar wind carbon, oxygen, neon, magnesium, silicon and iron. In the case of the SWICS data the magnetometer on-board ACE (ACE/MAG) allows us to directly relate the differential streaming to the ambient Alfvén velocity while the lack of in-situ magnetic field measurements on SOHO is compensated by a B-field extrapolation from the WIND spacecraft (WIND/MAG) to the SOHO site. Both instruments show a similar result: significant differential streaming between heavy ions and protons on the

  10. How Well Does the S-Web Theory Predict In-Situ Observations of the Slow Solar Wind?

    NASA Astrophysics Data System (ADS)

    Young, A. K.; Antiochos, S. K.; Linker, J.; Zurbuchen, T.

    2014-12-01

    The S-Web theory provides a physical explanation for the origin and properties of the slow solar wind, particularly its composition. The theory proposes that magnetic reconnection along topologically complex boundaries between open and closed magnetic fields on the sun releases plasma from closed magnetic field regions into the solar wind at latitudes away from the heliospheric current sheet. Such a wind would have elevated charge states compared to the fast wind and an elemental composition resembling the closed-field corona. This theory is currently being tested using time-dependent, high-resolution, MHD simulations, however comparisons to in-situ observations play an essential role in testing and understanding slow-wind release mechanisms. In order to determine the relationship between S-Web signatures and the observed, slow solar wind, we compare plasma data from the ACE and Ulysses spacecraft to solutions from the steady-state models created at Predictive Science, Inc., which use observed magnetic field distributions on the sun as a lower boundary condition. We discuss the S-Web theory in light of our results and the significance of the S-Web for interpreting current and future solar wind observations. This work was supported, in part, by the NASA TR&T and SR&T programs.

  11. 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

  12. 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.

  13. Searching for a Link Between Suprathermal Ions and Solar Wind Parameters During Quiet Times.

    NASA Astrophysics Data System (ADS)

    Nickell, J.; Desai, M. I.; Dayeh, M. A.

    2017-12-01

    The acceleration processes that suprathermal particles undergo are largely ambiguous. The two prevailing acceleration processes are: 1) Continuous acceleration in the IP space due to i) Bulk velocity fluctuations (e.g., Fahr et al. 2012), ii) magnetic compressions (e.g., Fisk and Gloeckler 2012), iii) magnetic field waves and turbulence (e.g., Zhang and Lee 2013), and iv) reconnection between magnetic islands (e.g., Drake et al. 2014) . 2) Discrete acceleration that occurs in discrete solar events such as CIRs, CME-driven shocks, and flares (e.g., Reames 1999, Desai et al. 2008). Using data from ACE/ULEIS during solar cycles 23 and 24 (1997-present), we examine the solar wind and magnetic field parameters during quiet-times (e.g., Dayeh et al. 2017) in an attempt to gain insights into the acceleration processes of the suprathermal particle population. In particular, we look for compression regions by performing comparative studies between solar wind and magnetic field parameters during quiet-times in the interplanetary space.

  14. Airborne Solar Radiant Flux Measurements During ACE-2

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Russell, Philip B.; Jonsson, Haflidi

    2000-01-01

    Aerosol effects on atmospheric radiative fluxes provide a forcing function that can change the climate in potentially significant ways. This aerosol radiative forcing is a major source of uncertainty in understanding the climate change of the past century and predicting future climate. To help reduce this uncertainty, the 1996 Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) and the 1997 Aerosol Characterization Experiment (ACE-2) measured the properties and radiative effects of aerosols over the Atlantic Ocean. In the ACE 2 program the solar radiant fluxes were measured on the Pelican aircraft and the UK Met Office C130. This poster will show results from the measurements for the aerosol effects during the clear column days. We will compare the results with calculations of the radiant fluxes.

  15. Reduced Solar Wind Speeds at New Horizons Beyond 30 AU

    NASA Astrophysics Data System (ADS)

    Elliott, H. A.; McComas, D. J.; Zirnstein, E.; Delamere, P. A.; Bagenal, F.; Stern, A.; Weaver, H. A., Jr.; Young, L. A.; Ennico Smith, K.; Olkin, C.

    2017-12-01

    Prior comparisons between Voyager 2 and IMP 8 observations found the solar wind had clearly decrease by 8% at a distance of 25 AU. Since mid-2016 solar rotation averaged speeds at New Horizons have been elevated relative to speeds observed in 2014 and 2015. However, we find a clear decrease in the New Horizons speeds beyond 30 AU when compared to those of ACE near Earth. At distances between 30-38.5 AU the relative speed reduction is in the 8-11% range. We will further this work by also comparing with available STEREO observations. By including STEREO, we can assess how sensitive the speed comparisons are to longitude separations and determine the appropriate time scale to average over.

  16. The Delta II with ACE aboard is prepared for liftoff from Pad 17A, CCAS

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Boeing Delta II expendable launch vehicle carrying the Advanced Composition Explorer (ACE) undergoes final preparations for liftoff in the predawn hours of Aug. 25, 1997, at Launch Complex 17A, Cape Canaveral Air Station. This is the second Delta launch under the Boeing name and the first from Cape Canaveral. The first launch attempt on Aug. 24 was scrubbed by Air Force range safety personnel because two commercial fishing vessels were within the Delta's launch danger area. ACE with its combination of nine sensors and instruments will investigate the origin and evolution of solar phenomenon, the formation of solar corona, solar flares and acceleration of the solar wind. ACE was built for NASA by the Johns Hopkins Applied Physics Laboratory and is managed by the Explorer Project Office at NASA's Goddard Space Flight Center. The lead scientific institution is the California Institute of Technology.

  17. Temporal and radial variation of the solar wind temperature-speed relationship

    NASA Astrophysics Data System (ADS)

    Elliott, H. A.; Henney, C. J.; McComas, D. J.; Smith, C. W.; Vasquez, B. J.

    2012-09-01

    The solar wind temperature (T) and speed (V) are generally well correlated at ˜1 AU, except in Interplanetary Coronal Mass Ejections where this correlation breaks down. We perform a comprehensive analysis of both the temporal and radial variation in the temperature-speed (T-V) relationship of the non-transient wind, and our analysis provides insight into both the causes of the T-V relationship and the sources of the temperature variability. Often at 1 AU the speed-temperature relationship is well represented by a single linear fit over a speed range spanning both the slow and fast wind. However, at times the fast wind from coronal holes can have a different T-V relationship than the slow wind. A good example of this was in 2003 when there was a very large and long-lived outward magnetic polarity coronal hole at low latitudes that emitted wind with speeds as fast as a polar coronal hole. The long-lived nature of the hole made it possible to clearly distinguish that some holes can have a different T-V relationship. In an earlier ACE study, we found that both the compressions and rarefactions T-V curves are linear, but the compression curve is shifted to higher temperatures. By separating compressions and rarefactions prior to determining the radial profiles of the solar wind parameters, the importance of dynamic interactions on the radial evolution of the solar wind parameters is revealed. Although the T-V relationship at 1 AU is often well described by a single linear curve, we find that the T-V relationship continually evolves with distance. Beyond ˜2.5 AU the differences between the compressions and rarefactions are quite significant and affect the shape of the overall T-V distribution to the point that a simple linear fit no longer describes the distribution well. Since additional heating of the ambient solar wind outside of interaction regions can be associated with Alfvénic fluctuations and the turbulent energy cascade, we also estimate the heating rate

  18. Assessment of Predictive Capabilities of L1 Orbiters using Realtime Solar Wind Data

    NASA Astrophysics Data System (ADS)

    Holmes, J.; Kasper, J. C.; Welling, D. T.

    2017-12-01

    Realtime measurements of solar wind conditions at L1 point allow us to predict geomagnetic activity at Earth up to an hour in advance. These predictions are quantified in the form of geomagnetic indices such as Kp and Ap, allowing for a concise, standardized prediction and measurement system. For years, the Space Weather Prediction Center used ACE realtime solar wind data to develop its one and four-hour Kp forecasts, but has in the past year switched to using DSCOVR data as its source. In this study, the performance of both orbiters in predicting Kp over the course of one month was assessed in an attempt to determine whether or not switching to DSCOVR data has resulted in improved forecasts. The period of study was chosen to encompass a time when the satellites were close to each other, and when moderate to high activity was observed. Kp predictions were made using the Geospace Model, part of the Space Weather Modeling Framework, to simulate conditions based on observed solar wind parameters. The performance of each satellite was assessed by comparing the model output to observed data.

  19. X-ray Magnetosheath Emission from Solar Wind Charge Exchange During Two CME Events in 2001

    NASA Astrophysics Data System (ADS)

    Sembay, S.; Whittaker, I. C.; Read, A.; Carter, J. A.; Milan, S. E.; Palmroth, M.

    2016-12-01

    Using a combination of the GUMICS-4 MHD model and observed solar wind heavy ion abundances from ACE, we produce case studies looking at X-ray emission from charge exchange in the Earth's magnetosheath. We specifically look in the 0.5-0.7 keV range, which is dominated by highly ionised oxygen emission. Previous studies looking at solar wind charge exchange (SWCX) emission have verified our modelling process via comparison to the XMM-Newton X-ray observatory, and we use the same simulation process here. This study investigates the emission magnitude changes that occur during two coronal mass ejection (CME) events (31 March 2001 and 21 October 2001). As part of this work we also provide a novel masking technique to exclude the plasma of terrestrial origin in the MHD model. As expected the two CME cases examined provide an increased dynamic pressure which pushes the magnetopause closer to the Earth, with a high temporal variation. We show how these changes cause an increase in the peak SWCX emission signature by over an order of magnitude from the quiescent solar wind case. Imaging of this SWCX emission allows a global view of the magnetopause shape and position, a technique planned for future missions such as SMILE (Solar wind Magnetosphere Ionosphere Link Explorer).

  20. 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

  1. 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

  2. The First Year of Solar-Wind Data From the GENESIS Mission

    NASA Astrophysics Data System (ADS)

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

    2002-12-01

    The GENESIS mission was launched in August, 2001, and has been in an L1 halo orbit for over a year. The primary purpose of the mission is to collect solar-wind samples that will be returned to Earth in 2004 for high-precision isotopic and elemental analyses. GENESIS uses conventional ion and electron spectrometers to record solar-wind conditions during collection, and to make real-time determinations of the solar-wind regimes to facilitate collection of separate samples of interstream (IS), coronal hole (CH), and coronal mass ejection (CME) flows. Of particular interest is the use of a bi-directional electron (BDE) index to determine the presence of CMEs. And although GENESIS lacks a magnetometer, the field vector, with sign ambiguity, is determined by the electron direction, and matches other spacecraft magnetometer data well. GENESIS in-situ data and on-board regime determinations are available on the web. The data from Fall, 2001 were characterized by numerous CME regimes (comprising 32% of the time in the 4th quarter, based on the on-board algorithm), with little CH flow (only 2%). A strong CH flow was observed every solar rotation from mid-January through late May. June was quiet, nearly all IS flow. The first and second quarters of 2002 were approximately 28% CME flow, with CH flow dropping from 18% to 6%. The discovery of unexpectedly noticeable BDE signals during CH flows at 1 AU (Steinberg et al., 2002) caused us early on to modify our regime selection algorithm to accommodate these. The on-board algorithm intentionally errs on the side of overestimating CME flows in order to keep the CH sample more pure. Comparisons have been made of various compositional parameters determined by Genesis (Barraclough et al., this meeting) and by ACE SWICS (Reisenfeld et al., this meeting) for times corresponding to the Genesis collection periods for each of the three regimes. The Genesis L1 halo orbit is ~0.8 x 0.25 million km radius, somewhat larger than the ~0.3 x 0

  3. 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.

  4. 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

  5. 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...

  6. Solar wind driven empirical forecast models of the time derivative of the ground magnetic field

    NASA Astrophysics Data System (ADS)

    Wintoft, Peter; Wik, Magnus; Viljanen, Ari

    2015-03-01

    Empirical models are developed to provide 10-30-min forecasts of the magnitude of the time derivative of local horizontal ground geomagnetic field (|dBh/dt|) over Europe. The models are driven by ACE solar wind data. A major part of the work has been devoted to the search and selection of datasets to support the model development. To simplify the problem, but at the same time capture sudden changes, 30-min maximum values of |dBh/dt| are forecast with a cadence of 1 min. Models are tested both with and without the use of ACE SWEPAM plasma data. It is shown that the models generally capture sudden increases in |dBh/dt| that are associated with sudden impulses (SI). The SI is the dominant disturbance source for geomagnetic latitudes below 50° N and with minor contribution from substorms. However, at occasions, large disturbances can be seen associated with geomagnetic pulsations. For higher latitudes longer lasting disturbances, associated with substorms, are generally also captured. It is also shown that the models using only solar wind magnetic field as input perform in most cases equally well as models with plasma data. The models have been verified using different approaches including the extremal dependence index which is suitable for rare events.

  7. 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.

  8. Cosmic Ray Helium Intensities over the Solar Cycle from ACE

    NASA Technical Reports Server (NTRS)

    DeNolfo, G. A.; Yanasak, N. E.; Binns, W. R.; Cohen, C. M. S.; Cummings, A. C.; Davis, A. J.; George, J. S.; Hink. P. L.; Israel, M. H.; Lave, K.; hide

    2007-01-01

    Observations of cosmic-ray helium energy spectra provide important constraints on cosmic ray origin and propagation. However, helium intensities measured at Earth are affected by solar modulation, especially below several GeV/nucleon. Observations of helium intensities over a solar cycle are important for understanding how solar modulation affects galactic cosmic ray intensities and for separating the contributions of anomalous and galactic cosmic rays. The Cosmic Ray Isotope Spectrometer (CRIS) on ACE has been measuring cosmic ray isotopes, including helium, since 1997 with high statistical precision. We present helium elemental intensities between approx. 10 to approx. 100 MeV/nucleon from the Solar Isotope Spectrometer (SIS) and CRIS observations over a solar cycle and compare these results with the observations from other satellite and balloon-borne instruments, and with GCR transport and solar modulation models.

  9. 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

  10. Prediction of AL and Dst Indices from ACE Measurements Using Hybrid Physics/Black-Box Techniques

    NASA Astrophysics Data System (ADS)

    Spencer, E.; Rao, A.; Horton, W.; Mays, L.

    2008-12-01

    ACE measurements of the solar wind velocity, IMF and proton density is used to drive a hybrid Physics/Black- Box model of the nightside magnetosphere. The core physics is contained in a low order nonlinear dynamical model of the nightside magnetosphere called WINDMI. The model is augmented by wavelet based nonlinear mappings between the solar wind quantities and the input into the physics model, followed by further wavelet based mappings of the model output field aligned currents onto the ground based magnetometer measurements of the AL index and Dst index. The black box mappings are introduced at the input stage to account for uncertainties in the way the solar wind quantities are transported from the ACE spacecraft at L1 to the magnetopause. Similar mappings are introduced at the output stage to account for a spatially and temporally varying westward auroral electrojet geometry. The parameters of the model are tuned using a genetic algorithm, and trained using the large geomagnetic storm dataset of October 3-7 2000. It's predictive performance is then evaluated on subsequent storm datasets, in particular the April 15-24 2002 storm. This work is supported by grant NSF 7020201

  11. Solar Energetic Particle Composition over Two Solar Cycles as Observed by the Ulysses/HISCALE and ACE/EPAM Pulse Height Analyzers.

    NASA Astrophysics Data System (ADS)

    Patterson, J. D.; Madanian, H.; Manweiler, J. W.; Lanzerotti, L. J.

    2017-12-01

    We present the compositional variation in the Solar Energetic Particle (SEP) population in the inner heliosphere over two solar cycles using data from the Ulysses Heliospheric Instrument for Spectra, Composition, and Anisotropy at Low Energies (HISCALE) and Advanced Composition Explorer (ACE) Electron Proton Alpha Monitor (EPAM). The Ulysses mission was active from late 1990 to mid-2009 in a heliopolar orbit inclined by 80° with a perihelion of 1.3 AU and an aphelion of 5.4 AU. The ACE mission has been active since its launch in late 1997 and is in a halo orbit about L1. These two missions provide a total of 27 years of continuous observation in the inner heliosphere with twelve years of simultaneous observation. HISCALE and EPAM data provide species-resolved differential flux and density of SEP between 0.5-5 MeV/nuc. Several ion species (He, C, O, Ne, Si, Fe) are identified using the Pulse Height Analyzer (PHA) system of the Composition Aperture for both instruments. The He density shows a noticeable increase at high solar activity followed by a moderate drop at the quiet time of the solar minimum between cycles 23 and 24. The density of heavier ions (i.e. O and Fe) change minimally with respect to the F10.7 index variations however, certain energy-specific count rates decrease during solar minimum. With Ulysses and ACE observing in different regions of the inner heliosphere, there are significant latitudinal differences in how the O/He ratios vary with the solar cycle. At solar minimum, there is reasonable agreement between the observations from both instruments. At solar max 23, the differences in composition over the course of the solar cycle, and as observed at different heliospheric locations can provide insight to the origins of and acceleration processes differentially affecting solar energetic ions.

  12. Fundamental Physics of the Slow Solar Wind - What do we Know?

    NASA Astrophysics Data System (ADS)

    Ofman, L.; Abbo, L.; Antiochos, S. K.; Hansteen, V. H.; Harra, L.; Ko, Y. K.; Lapenta, G.; Li, B.; Riley, P.; Strachan, L.; von Steiger, R.; Wang, Y. M.

    2016-12-01

    Fundamental physical properties of the slow solar wind (SSW), such as density, temperature, outflow speed, heavy ion abundances and charges states were obtained from in-situ measurements at 1AU in the past from WIND, ACE, and other spacecraft. Plasma and magnetic field measurement are available as close as 0.3 AU from Helios data, Spektr-R, and MESSENGER spacecraft. Remote sensing spectroscopic measurements are available in the corona and below from SOHO/UVCS, Hinode, and other missions. One of the major objectives of the Solar Orbiter and Solar Probe Plus missions is to study the sources of the SSW close to the Sun. The present state of understanding of the physics of the SSW is based on the combination of the existing observations, theoretical and numerical 3D MHD and multi-fluid models, that connect between the SSW sources in the corona and the heliosphere. Recently, hybrid models that combine fluid electrons and kinetic ions of the expanding solar wind were developed, and provide further insights of the local SSW plasma heating processes that related to turbulent magnetic fluctuations spectra and kinetic ion instabilities observed in the SSW plasma. These models produce the velocity distribution functions (VDFs) of the protons and heavier ions as well as the ion anisotropic temperatures. I will discuss the results of the above observations and models, and review the current status of our understanding of the fundamental physics of the SSW. I will review the open questions, and discuss how they could be addressed with near future observations and models.

  13. 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.

  14. PC index as a proxy of the solar wind energy that entered into the magnetosphere: 2. Relation to the interplanetary electric field E KL before substorm onset

    NASA Astrophysics Data System (ADS)

    Troshichev, O. A.; Sormakov, D. A.

    2015-10-01

    This paper (the second of a series) presents the results of statistical investigation of relationship between the interplanetary electric field E KL and the Polar Cap (PC) index in case of magnetic substorms (1998-2001), which have been analyzed in Troshichev et al. (J. Geophys. Res. Space Physics, 119, 2014). The PC index is directly related to the E KL field variations on interval preceding the substorm sudden onset (SO): correlation R > 0.5 is typical of more than 90 % of isolated substorms, 80 % of expanded substorms, and 99 % of events with coordinated E KL and PC jumps. The low or negative correlation observing in ~10 % of examined substorms suggests that the solar wind flow measured by the Advanced Composition Explorer (ACE) spacecraft in the Lagrange point L1 did not encounter the magnetosphere in these cases. Examination of the delay times Δ T in the response of PC index to E KL variations provides the following results: (1) delay times do not depend on separate solar wind parameters, such as solar wind speed V X and interplanetary magnetic field (IMF) B Z component, contrary to general conviction, (2) the Δ T value is best controlled by the E KL field growth rate (d E KL/dt), (3) the lower Δ T limit (5-7 min is attained under conditions of the higher E KL growth rate, and (4) the PC index provides the possibility to verify the solar wind flow transportation time from ACE position (where the solar wind speed is estimated) to magnetosphere. These results, in combination with data testifying that the substorm onsets are related to the PC precursors, demonstrate that the PC index is an adequate ground-based indicator of the solar wind energy incoming into the magnetosphere.

  15. Solar wind and magnetosphere interactions

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Allen, J. H.; Cauffman, D. P.; Feynman, J.; Greenstadt, E. W.; Holzer, R. E.; Kaye, S. M.; Slavin, J. A.; Manka, R. H.; Rostoker, G.

    1979-01-01

    The relationship between the magnetosphere and the solar wind is addressed. It is noted that this interface determines how much of the solar plasma and field energy is transferred to the Earth's environment, and that this coupling not only varies in time, responding to major solar disturbances, but also to small changes in solar wind conditions and interplanetary field directions. It is recommended that the conditions of the solar wind and interplanetary medium be continuously monitored, as well as the state of the magnetosphere. Other recommendations include further study of the geomagnetic tail, tests of Pc 3,4 magnetic pulsations as diagnostics of the solar wind, and tests of kilometric radiation as a remote monitor of the auroral electrojet.

  16. A Data Services Upgrade for Advanced Composition Explorer (ACE) Data

    NASA Astrophysics Data System (ADS)

    Davis, A. J.; Hamell, G.

    2008-12-01

    Since early in 1998, NASA's Advanced Composition Explorer (ACE) spacecraft has provided continuous measurements of solar wind, interplanetary magnetic field, and energetic particle activity from L1, located approximately 0.01 AU sunward of Earth. The spacecraft has enough fuel to stay in orbit about L1 until ~2024. The ACE Science Center (ASC) provides access to ACE data, and performs level 1 and browse data processing for the science instruments. Thanks to a NASA Data Services Upgrade grant, we have recently retooled our legacy web interface to ACE data, enhancing data subsetting capabilities and improving online plotting options. We have also integrated a new application programming interface (API) and we are working to ensure that it will be compatible with emerging Virtual Observatory (VO) data services standards. The new API makes extensive use of metadata created using the Space Physics Archive Search and Extract (SPASE) data model. We describe these recent improvements to the ACE Science Center data services, and our plans for integrating these services into the VO system.

  17. 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

  18. 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.

  19. 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.

  20. The Influence of Pickup Protons, from Interstellar Neutral Hydrogen, on the Propagation of Interplanetary Shocks from the Halloween 2003 Solar Events to ACE and Ulysses: A 3-D MHD Modeling Study

    NASA Technical Reports Server (NTRS)

    Detman, T. R.; Intriligator, D. S.; Dryer, M.; Sun, W.; Deehr, C. S.; Intriligator, J.

    2012-01-01

    We describe our 3-D, time ]dependent, MHD solar wind model that we recently modified to include the physics of pickup protons from interstellar neutral hydrogen. The model has a time-dependent lower boundary condition, at 0.1 AU, that is driven by source surface map files through an empirical interface module. We describe the empirical interface and its parameter tuning to maximize model agreement with background (quiet) solar wind observations at ACE. We then give results of a simulation study of the famous Halloween 2003 series of solar events. We began with shock inputs from the Fearless Forecast real ]time shock arrival prediction study, and then we iteratively adjusted input shock speeds to obtain agreement between observed and simulated shock arrival times at ACE. We then extended the model grid to 5.5 AU and compared those simulation results with Ulysses observations at 5.2 AU. Next we undertook the more difficult tuning of shock speeds and locations to get matching shock arrival times at both ACE and Ulysses. Then we ran this last case again with neutral hydrogen density set to zero, to identify the effect of pickup ions. We show that the speed of interplanetary shocks propagating from the Sun to Ulysses is reduced by the effects of pickup protons. We plan to make further improvements to the model as we continue our benchmarking process to 10 AU, comparing our results with Cassini observations, and eventually on to 100 AU, comparing our results with Voyager 1 and 2 observations.

  1. 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.

  2. Real-Time Visualization Tool Integrating STEREO, ACE, SOHO and the SDO

    NASA Astrophysics Data System (ADS)

    Schroeder, P. C.; Luhmann, J. G.; Marchant, W.

    2011-12-01

    The STEREO/IMPACT team has developed a new web-based visualization tool for near real-time data from the STEREO instruments, ACE and SOHO as well as relevant models of solar activity. This site integrates images, solar energetic particle, solar wind plasma and magnetic field measurements in an intuitive way using near real-time products from NOAA and other sources to give an overview of recent space weather events. This site enhances the browse tools already available at UC Berkeley, UCLA and Caltech which allow users to visualize similar data from the start of the STEREO mission. Our new near real-time tool utilizes publicly available real-time data products from a number of missions and instruments, including SOHO LASCO C2 images from the SOHO team's NASA site, SDO AIA images from the SDO team's NASA site, STEREO IMPACT SEP data plots and ACE EPAM data plots from the NOAA Space Weather Prediction Center and STEREO spacecraft positions from the STEREO Science Center.

  3. Electrostatic Solitary Waves in the Solar Wind: Evidence for Instability at Solar Wind Current Sheets

    NASA Technical Reports Server (NTRS)

    Malaspina, David M.; Newman, David L.; Wilson, Lynn Bruce; Goetz, Keith; Kellogg, Paul J.; Kerstin, Kris

    2013-01-01

    A strong spatial association between bipolar electrostatic solitary waves (ESWs) and magnetic current sheets (CSs) in the solar wind is reported here for the first time. This association requires that the plasma instabilities (e.g., Buneman, electron two stream) which generate ESWs are preferentially localized to solar wind CSs. Distributions of CS properties (including shear angle, thickness, solar wind speed, and vector magnetic field change) are examined for differences between CSs associated with ESWs and randomly chosen CSs. Possible mechanisms for producing ESW-generating instabilities at solar wind CSs are considered, including magnetic reconnection.

  4. 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.

  5. An Unusual Coronal Mass Ejection: First Solar Wind Electron, Proton, Alpha Monitor (SWEPAM) Results from the Advanced Composition Explorer. Appendix 6

    NASA Technical Reports Server (NTRS)

    McComas, D. J.; Bame, S. J.; Barker, P. L.; Delapp, D. M.; Gosling, J. T.; Skoug, R. M.; Tokar, R. L.; Riley, P.; Feldman, W. C.; Santiago, E.

    2001-01-01

    This paper reports the first scientific results from the Solar Wind Electron Proton Alpha Monitor (SWEPAM) instrument on board the Advanced Composition Explorer (ACE) spacecraft. We analyzed a coronal mass ejection (CME) observed in the solar wind using data from early February, 1998. This event displayed several of the common signatures of CMEs, such as counterstreaming halo electrons and depressed ion and electron temperatures, as well as some unusual features. During a portion of the CME traversal, SWEPAM measured a very large helium to proton abundance ratio. Other heavy ions, with a set of ionization states consistent with normal (1 to 2x10(exp 6) K) coronal temperatures, were proportionately enhanced at this time. These observations suggest a source for at least some of the CME material, where heavy ions are initially concentrated relative to hydrogen and then accelerated up into the solar wind, independent of their mass and first ionization potential.

  6. 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.

  7. Magnetosheath for almost-aligned solar wind magnetic field and flow vectors: Wind observations across the dawnside magnetosheath at X = -12 Re

    NASA Astrophysics Data System (ADS)

    Farrugia, C. J.; Erkaev, N. V.; Torbert, R. B.; Biernat, H. K.; Gratton, F. T.; Szabo, A.; Kucharek, H.; Matsui, H.; Lin, R. P.; Ogilvie, K. W.; Lepping, R. P.; Smith, C. W.

    2010-08-01

    While there are many approximations describing the flow of the solar wind past the magnetosphere in the magnetosheath, the case of perfectly aligned (parallel or anti-parallel) interplanetary magnetic field (IMF) and solar wind flow vectors can be treated exactly in a magnetohydrodynamic (MHD) approach. In this work we examine a case of nearly-opposed (to within 15°) interplanetary field and flow vectors, which occurred on October 24-25, 2001 during passage of the last interplanetary coronal mass ejection in an ejecta merger. Interplanetary data are from the ACE spacecraft. Simultaneously Wind was crossing the near-Earth (X ˜ -13 Re) geomagnetic tail and subsequently made an approximately 5-hour-long magnetosheath crossing close to the ecliptic plane (Z = -0.7 Re). Geomagnetic activity was returning steadily to quiet, “ground” conditions. We first compare the predictions of the Spreiter and Rizzi theory with the Wind magnetosheath observations and find fair agreement, in particular as regards the proportionality of the magnetic field strength and the product of the plasma density and bulk speed. We then carry out a small-perturbation analysis of the Spreiter and Rizzi solution to account for the small IMF components perpendicular to the flow vector. The resulting expression is compared to the time series of the observations and satisfactory agreement is obtained. We also present and discuss observations in the dawnside boundary layer of pulsed, high-speed (v ˜ 600 km/s) flows exceeding the solar wind flow speeds. We examine various generating mechanisms and suggest that the most likely cause is a wave of frequency 3.2 mHz excited at the inner edge of the boundary layer by the Kelvin-Helmholtz instability.

  8. 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.

  9. Exact solutions of magnetohydrodynamics for describing different structural disturbances in solar wind

    NASA Astrophysics Data System (ADS)

    Grib, S. A.; Leora, S. N.

    2016-03-01

    We use analytical methods of magnetohydrodynamics to describe the behavior of cosmic plasma. This approach makes it possible to describe different structural fields of disturbances in solar wind: shock waves, direction discontinuities, magnetic clouds and magnetic holes, and their interaction with each other and with the Earth's magnetosphere. We note that the wave problems of solar-terrestrial physics can be efficiently solved by the methods designed for solving classical problems of mathematical physics. We find that the generalized Riemann solution particularly simplifies the consideration of secondary waves in the magnetosheath and makes it possible to describe in detail the classical solutions of boundary value problems. We consider the appearance of a fast compression wave in the Earth's magnetosheath, which is reflected from the magnetosphere and can nonlinearly overturn to generate a back shock wave. We propose a new mechanism for the formation of a plateau with protons of increased density and a magnetic field trough in the magnetosheath due to slow secondary shock waves. Most of our findings are confirmed by direct observations conducted on spacecrafts (WIND, ACE, Geotail, Voyager-2, SDO and others).

  10. 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.

  11. 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.

  12. Relative Heating of Heavy Ions Observed at 1 AU with ACE/SWICS

    NASA Astrophysics Data System (ADS)

    Tracy, P.; Kasper, J. C.; Zurbuchen, T.; Raines, J. M.; Gilbert, J. A.

    2015-12-01

    Heavy ions (Z>4) observed near 1 AU, especially in fast solar wind, tend to have thermal speeds that are approximately equal, indicative of a mass proportional temperature. The fact that these heavy ions have similar thermal speeds implies that they have very different temperatures, and furthermore, that they are far from thermal equilibrium. By comparing the observed heavy ion temperatures amongst species with different mass and charge values we can critically evaluate heating theories for the solar wind. Utilizing improved data processing techniques, results from the Solar Wind Ion Composition Spectrometer (SWICS) onboard the Advanced Composition Explorer (ACE) are used to analyze the thermal properties of the heavy ion population at 1 AU. We have shown in previous work that Coulomb Collisional relaxation has a significant effect on these heavy ion populations, and now we investigate how Coulomb Collisions effect the observed temperature ratios of different heavy ion species. We observe that the heavy ion to proton temperature ratio scales with the mass and charge values of species analyzed. These dependencies are compared to current heating theories to determine which best explains the observations. The results of this work are valuable for comparison with coronal spectroscopic observations of ion temperatures, existing solar wind observations at different distances from the Sun, and for predictions of the environment to be encountered by Solar Probe and Solar Orbiter.

  13. 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.

  14. Solar wind acceleration in the solar corona

    NASA Technical Reports Server (NTRS)

    Giordano, S.; Antonucci, E.; Benna, C.; Kohl, J. L.; Noci, G.; Michels, J.; Fineschi, S.

    1997-01-01

    The intensity ratio of the O VI doublet in the extended area is analyzed. The O VI intensity data were obtained with the ultraviolet coronagraph spectrometer (UVCS) during the SOHO campaign 'whole sun month'. The long term observations above the north pole of the sun were used for the polar coronal data. Using these measurements, the solar wind outflow velocity in the extended corona was determined. The 100 km/s level is running along the streamer borders. The acceleration of the solar wind is found to be high in regions between streamers. In the central part of streamers, the outflow velocity of the coronal plasma remains below 100 km/s at least within 3.8 solar radii. The regions at the north and south poles, characterized by a more rapid acceleration of the solar wind, correspond to regions where the UVCS observes enhanced O VI line broadenings.

  15. 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.

  16. Investigation of the variance and spectral anisotropies of the solar wind turbulence with multiple point spacecraft observations

    NASA Astrophysics Data System (ADS)

    Vech, Daniel; Chen, Christopher

    2016-04-01

    One of the most important features of the plasma turbulence is the anisotropy, which arises due to the presence of the magnetic field. The understanding of the anisotropy is particularly important to reveal how the turbulent cascade operates. It is well known that anisotropy exists with respect to the mean magnetic field, however recent theoretical studies suggested anisotropy with respect to the radial direction. The purpose of this study is to investigate the variance and spectral anisotropies of the solar wind turbulence with multiple point spacecraft observations. The study includes the Advanced Composition Analyzer (ACE), WIND and Cluster spacecraft data. The second order structure functions are derived for two different spacecraft configurations: when the pair of spacecraft are separated radially (with respect to the spacecraft -Sun line) and when they are separated along the transverse direction. We analyze the effect of the different sampling directions on the variance anisotropy, global spectral anisotropy, local 3D spectral anisotropy and discuss the implications for our understanding of solar wind turbulence.

  17. EFFECT OF COHERENT STRUCTURES ON ENERGETIC PARTICLE INTENSITY IN THE SOLAR WIND AT 1 AU

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

    Tessein, Jeffrey A.; Matthaeus, William H.; Wan, Minping

    2015-10-10

    We present results from an analysis of Advanced Composition Explorer (ACE) observations of energetic particles in the 0.047–4.78 MeV range associated with shocks and discontinuities in the solar wind. Previous work found a strong correlation between coherent structures and energetic particles measured by ACE/EPAM. Coherent structures are identified using the Partial Variance of Increments (PVI) method, which is essentially a normalized vector increment. The correlation was based on a superposed epoch analysis using over 12 years of data. Here, we examine many individual high-PVI events to better understand this association emphasizing intervals selected from data with shock neighborhoods removed. Wemore » find that in many cases the local maximum in PVI is in a region of rising or falling energetic particle intensity, which suggests that magnetic discontinuities may act as barriers inhibiting the motion of energetic particles across them.« less

  18. 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

  19. 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.

  20. Distinct EUV minimum of the solar irradiance (16-40 nm) observed by SolACES spectrometers onboard the International Space Station (ISS) in August/September 2009

    NASA Astrophysics Data System (ADS)

    Nikutowski, B.; Brunner, R.; Erhardt, Ch.; Knecht, St.; Schmidtke, G.

    2011-09-01

    In the field of terrestrial climatology the continuous monitoring of the solar irradiance with highest possible accuracy is an important goal. SolACES as a part of the ESA mission SOLAR on the ISS is measuring the short-wavelength solar EUV irradiance from 16-150 nm. This data will be made available to the scientific community to investigate the impact of the solar irradiance variability on the Earth's climate as well as the thermospheric/ionospheric interactions that are pursued in the TIGER program. Since the successful launch with the shuttle mission STS-122 on February 7th, 2008, SolACES initially recorded the low EUV irradiance during the extended solar activity minimum. Thereafter it has been observing the EUV irradiance during the increasing solar activity with enhanced intensity and changing spectral composition. SolACES consists of three grazing incidence planar grating spectrometers. In addition there are two three-signal ionisation chambers, each with exchangeable band-pass filters to determine the absolute EUV fluxes repeatedly during the mission. One important problem of space-borne instrumentation recording the solar EUV irradiance is the degradation of the spectrometer sensitivity. The two double ionisation chambers of SolACES, which could be re-filled with three different gases for each recording, allow the recalibration of the efficiencies of the three SolACES spectrometers from time to time.

  1. On the Role of Solar Wind Discontinuities in the ULF Power Spectral Density at the Earth's Outer Radiation Belt: a Case Study

    NASA Astrophysics Data System (ADS)

    Lago, A.; Alves, L. R.; Braga, C. R.; Mendonca, R. R. S.; Jauer, P. R.; Medeiros, C.; Souza, V. M. C. E. S.; Mendes, O., Jr.; Marchezi, J.; da Silva, L.; Vieira, L.; Rockenbach, M.; Sibeck, D. G.; Kanekal, S. G.; Baker, D. N.; Wygant, J. R.; Kletzing, C.

    2016-12-01

    The solar wind incident upon the Earth's magnetosphere can produce either enhancement, depletion or no change in the flux of relativistic electrons at the outer radiation belt. During geomagnetic storms progress, solar wind parameters may change significantly, and occasionally relativistic electron fluxes at the outer radiation belt show dropouts in a range of energy and L-shells. Wave-particle interactions observed within the Van Allen belts have been claimed to play a significant role in energetic particle flux changes. The relation between changes on the solar wind parameters and the radiation belt is still a hot topic nowadays, particularly the role played by the solar wind on sudden electron flux decreases. The twin satellite Van Allen Probes measured a relativistic electron flux dropout concurrent to broad band Ultra-low frequency (ULF) waves, i.e. from 1 mHz to 10 Hz, on October 2, 2013. Magnetic field and plasma data from both ACE and WIND satellites allowed the characterization of this event as being an interplanetary coronal mass ejection in conjunction with shock. The interaction of this event with the Earth's magnetosphere was modeled using a global magnetohydrodynamic simulation and the magnetic field perturbation deep in magnetosphere could be analyzed from the model outputs. Results show the contribution of time-varying solar wind parameters to the generation of ULF waves. The power spectral densities, as a function of L-shell, were evaluated considering changes in the input parameters, e.g. magnitude and duration of dynamic pressure and magnetic field. The modeled power spectral densities are compared with Van Allen Probes data. The results provide us a clue on the solar wind characteristics that might be able to drive ULF waves in the inner magnetosphere, and also which wave modes are expected to be excited under a specific solar wind driving.

  2. Preparing GMAT for Operational Maneuver Planning of the Advanced Composition Explorer (ACE)

    NASA Technical Reports Server (NTRS)

    Qureshi, Rizwan Hamid; Hughes, Steven P.

    2014-01-01

    The General Mission Analysis Tool (GMAT) is an open-source space mission design, analysis and trajectory optimization tool. GMAT is developed by a team of NASA, private industry, public and private contributors. GMAT is designed to model, optimize and estimate spacecraft trajectories in flight regimes ranging from low Earth orbit to lunar applications, interplanetary trajectories and other deep space missions. GMAT has also been flight qualified to support operational maneuver planning for the Advanced Composition Explorer (ACE) mission. ACE was launched in August, 1997 and is orbiting the Sun-Earth L1 libration point. The primary science objective of ACE is to study the composition of both the solar wind and the galactic cosmic rays. Operational orbit determination, maneuver operations and product generation for ACE are conducted by NASA Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF). This paper discusses the entire engineering lifecycle and major operational certification milestones that GMAT successfully completed to obtain operational certification for the ACE mission. Operational certification milestones such as gathering of the requirements for ACE operational maneuver planning, gap analysis, test plans and procedures development, system design, pre-shadow operations, training to FDF ACE maneuver planners, shadow operations, Test Readiness Review (TRR) and finally Operational Readiness Review (ORR) are discussed. These efforts have demonstrated that GMAT is flight quality software ready to support ACE mission operations in the FDF.

  3. 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.

  4. 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.

  5. The Solar Wind Environment in Time

    NASA Astrophysics Data System (ADS)

    Pognan, Quentin; Garraffo, Cecilia; Cohen, Ofer; Drake, Jeremy J.

    2018-03-01

    We use magnetograms of eight solar analogs of ages 30 Myr–3.6 Gyr obtained from Zeeman Doppler Imaging and taken from the literature, together with two solar magnetograms, to drive magnetohydrodynamical wind simulations and construct an evolutionary scenario of the solar wind environment and its angular momentum loss rate. With observed magnetograms of the radial field strength as the only variant in the wind model, we find that a power-law model fitted to the derived angular momentum loss rate against time, t, results in a spin-down relation Ω ∝ t ‑0.51, for angular speed Ω, which is remarkably consistent with the well-established Skumanich law Ω ∝ t ‑0.5. We use the model wind conditions to estimate the magnetospheric standoff distances for an Earth-like test planet situated at 1 au for each of the stellar cases, and to obtain trends of minimum and maximum wind ram pressure and average ram pressure in the solar system through time. The wind ram pressure declines with time as \\overline{{P}ram}}\\propto {t}2/3, amounting to a factor of 50 or so over the present lifetime of the solar system.

  6. 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

  7. 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.

  8. 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

  9. 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

  10. Pluto-Charon solar wind interaction dynamics

    NASA Astrophysics Data System (ADS)

    Hale, J. P. M.; Paty, C. S.

    2017-05-01

    This work studies Charon's effects on the Pluto-solar wind interaction using a multifluid MHD model which simulates the interactions of Pluto and Charon with the solar wind as well as with each other. Specifically, it investigates the ionospheric dynamics of a two body system in which either one or both bodies possess an ionosphere. Configurations in which Charon is directly upstream and directly downstream of Pluto are considered. Depending on ionospheric and solar wind conditions, Charon could periodically pass into the solar wind flow upstream of Pluto. The results of this study demonstrate that in these circumstances Charon modifies the upstream flow, both in the case in which Charon possesses an ionosphere, and in the case in which Charon is without an ionosphere. This modification amounts to a change in the gross structure of the interaction region when Charon possesses an ionosphere but is more localized when Charon lacks an ionosphere. Furthermore, evidence is shown that supports Charon acting to partially shield Pluto from the solar wind when it is upstream of Pluto, resulting in a decrease in ionospheric loss by Pluto.

  11. 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

  12. Solar Wind Eight: Proceedings of the Eighth International Solar Wind Conference. Proceedings

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

    Winterhalter, D.; Gosling, J.T.; Habbal, S.R.

    1997-06-01

    These proceedings represent papers presented at the eighth international solar wind conference held at the Dana Point Resort, California. The conference was sponsored by the National Aeronautics and Space Administration(NASA), the National Science Foundation(NSF) and the Committee on space Research (COSPAR). The proceedings from this conference reflected the state of the art of solar wind research: its origin at the sun, the transport through the solar system, and its ultimate fate at the heliocentric boundaries. There were one hundred and seventy eight papers presented and nineteen papers for which the research was sponsored by the US Department of Energy havemore » been abstracted for the Energy Science and Technology database.(AIP)« less

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Solar wind physics

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A double-chambered gas proportional counter was constructed to detect and identify solar wind ions after acceleration by a high voltage power supply. It was determined that the best method of detecting deuterium in the solar wind is to use a tritium target as proposed for IMP H and J. The feasibility of detecting H(+) and He(+) ions of interstellar origin is considered. A program is described to carry out ground-based astronomical observations of faint, diffuse optical emission lines from interstellar gas. Hydrogen and oxygen emission lines from galactic sources were detected and the galactic and geocoronal H alpha and beta lines were clearly resolved.

  1. 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.

  2. 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.

  3. Flank solar wind interaction

    NASA Technical Reports Server (NTRS)

    Moses, Stewart L.; Greenstadt, Eugene W.; Coroniti, Ferdinand V.

    1994-01-01

    In this report we will summarize the results of the work performed under the 'Flank Solar Wind Interaction' investigation in support of NASA's Space Physics Guest Investigator Program. While this investigation was focused on the interaction of the Earth's magnetosphere with the solar wind as observed by instruments on the International Sun-Earth Explorer (ISEE) 3 spacecraft, it also represents the culmination of decades of research performed by scientists at TRW on the rich phenomenology of collisionless shocks in space.

  4. 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.

  5. 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.

  6. Solar cycle variations of the solar wind

    NASA Technical Reports Server (NTRS)

    Crooker, N. U.

    1983-01-01

    Throughout the course of the past one and a half solar cycles, solar wind parameters measured near the ecliptic plane at 1 AU varied in the following way: speed and proton temperature have maxima during the declining phase and minima at solar minimum and are approximately anti-correlated with number density and electron temperature, while magnetic field magnitude and relative abundance of helium roughly follow the sunspot cycle. These variations are described in terms of the solar cycle variations of coronal holes, streamers, and transients. The solar wind signatures of the three features are discussed in turn, with special emphasis on the signature of transients, which is still in the process of being defined. It is proposed that magnetic clouds be identified with helium abundance enhancements and that they form the head of a transient surrounded by streamer like plasma, with an optional shock front. It is stressed that relative values of a parameter through a solar cycle should be compared beginning with the declining phase, especially in the case of magnetic field magnitude.

  7. Soft X-ray study of solar wind charge exchange from the Earth's magnetosphere : Suzaku observations and a future X-ray imaging mission concept

    NASA Astrophysics Data System (ADS)

    Ezoe, Y.; Ishisaki, Y.; Ohashi, T.; Ishikawa, K.; Miyoshi, Y.; Fujimoto, R.; Terada, N.; Kasahara, S.; Fujimoto, M.; Mitsuda, K.; Nishijo, K.; Noda, A.

    2013-12-01

    Soft X-ray observations of solar wind charge exchange (SWCX) emission from the Earth's magnetosphere using the Japanese X-ray astronomy satellite Suzaku are shown, together with our X-ray imaging mission concept to characterize the solar wind interaction with the magnetosphere. In recent years, the SWCX emission from the Earth's magnetosphere, originally discovered as unexplained noise during the soft X-ray all sky survey (Snowden et al. 1994), is receiving increased attention on studying geospace. The SWCX is a reaction between neutrals in exosphere and highly charged ions in the magnetosphere originated from solar wind. Robertson et al. (2005) modeled the SWCX emission as seen from an observation point 50 Re from Earth. In the resulting X-ray intensities, the magnetopause, bow shock and cusp were clearly visible. High sensitivity soft X-ray observation with CCDs onboard recent X-ray astronomy satellites enables us to resolve SWCX emission lines and investigate time correlation with solar wind as observed with ACE and WIND more accurately. Suzaku is the 5th Japanese X-ray astronomy satellite launched in 2005. The line of sight direction through cusp is observable, while constraints on Earth limb avoidance angle of other satellites often limits observable regions. Suzaku firstly detected the SWCX emission while pointing in the direction of the north ecliptic pole (Fujimoto et al. 2007). Using the Tsyganenko 1996 magnetic field model, the distance to the nearest SWCX region was estimated as 2-8 Re, implying that the line of sight direction can be through magnetospheric cusp. Ezoe et al. (2010) reported SWCX events toward the sub-solar side of the magnetosheath. These cusp and sub-solar side magnetosheath regions are predicted to show high SWCX fluxes by Robertson et al. (2005). On the other hand, Ishikawa et al. (2013) discovered a similarly strong SWCX event when the line of sight direction did not transverse these two regions. Motivated by these detections

  8. 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

  9. Distribution and solar wind control of compressional solar wind-magnetic anomaly interactions observed at the Moon by ARTEMIS

    NASA Astrophysics Data System (ADS)

    Halekas, J. S.; Poppe, A. R.; Lue, C.; Farrell, W. M.; McFadden, J. P.

    2017-06-01

    A statistical investigation of 5 years of observations from the two-probe Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) mission reveals that strong compressional interactions occur infrequently at high altitudes near the ecliptic but can form in a wide range of solar wind conditions and can occur up to two lunar radii downstream from the lunar limb. The compressional events, some of which may represent small-scale collisionless shocks ("limb shocks"), occur in both steady and variable interplanetary magnetic field (IMF) conditions, with those forming in steady IMF well organized by the location of lunar remanent crustal magnetization. The events observed by ARTEMIS have similarities to ion foreshock phenomena, and those observed in variable IMF conditions may result from either local lunar interactions or distant terrestrial foreshock interactions. Observed velocity deflections associated with compressional events are always outward from the lunar wake, regardless of location and solar wind conditions. However, events for which the observed velocity deflection is parallel to the upstream motional electric field form in distinctly different solar wind conditions and locations than events with antiparallel deflections. Consideration of the momentum transfer between incoming and reflected solar wind populations helps explain the observed characteristics of the different groups of events.Plain Language SummaryWe survey the environment around the Moon to determine when and where strong amplifications in the charged particle density and magnetic field strength occur. These structures may be some of the smallest shock waves in the <span class="hlt">solar</span> system, and learning about their formation informs us about the interaction of charged particles with small-scale magnetic fields throughout the <span class="hlt">solar</span> system and beyond. We find that these compressions occur in an extended region</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E%26PSL.492..222O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E%26PSL.492..222O"><span>Were chondrites magnetized by the early <span class="hlt">solar</span> <span class="hlt">wind</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oran, Rona; Weiss, Benjamin P.; Cohen, Ofer</p> <p>2018-06-01</p> <p>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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. Here we demonstrate that the <span class="hlt">solar</span> <span class="hlt">wind</span> scenario is unlikely due to three main factors: 1) the magnitude of the early <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> to less than a factor of 3.5 times that of the instantaneous <span class="hlt">solar</span> <span class="hlt">wind</span> field, and 3) the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetic fields of young stars, we show that the maximum mean field the ancient <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> field in time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900027052&hterms=Fran&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DFran','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900027052&hterms=Fran&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DFran"><span>Pluto's interaction with the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bagenal, Fran; Mcnutt, Ralph L., Jr.</p> <p>1989-01-01</p> <p>If Pluto's atmospheric escape rate is significantly greater than 1.5 x 10 to the 27th molecules/s then the interaction with the tenuous <span class="hlt">solar</span> <span class="hlt">wind</span> at 30 A.U. will be like that of a comet. There will be extensive ion pick-up upstream and the size of the interaction region will vary directly with variations in the <span class="hlt">solar</span> <span class="hlt">wind</span> flux. If the escape flux is much less, then one expects that the <span class="hlt">solar</span> <span class="hlt">wind</span> will be deflected around Pluto's ionosphere in a Venus-like interaction. In either case, the weak interplanetary magnetic field at 30 A.U. results in very large gyroradii for the picked-up ions and a thick bow shock, necessitating a kinetic treatment of the interaction. Strong variations in the size of the interaction region are expected on time scales of days due to changes in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017nova.pres.2278K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017nova.pres.2278K"><span>Escape for the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohler, Susanna</p> <p>2017-05-01</p> <p>Plasma from the Sun known as the slow <span class="hlt">solar</span> <span class="hlt">wind</span> has been observed far away from where scientists thought it was produced. Now new simulations may have resolved the puzzle of where the slow <span class="hlt">solar</span> <span class="hlt">wind</span> comes from and how it escapes the Sun to travel through our <span class="hlt">solar</span> system.An Origin PuzzleA full view of a coronal hole (dark portion) from SDO. The edges of the coronal hole mark the boundary between open and closed magnetic field lines. [SDO; adapted from Higginson et al. 2017]The Suns atmosphere, known as the corona, is divided into two types of regions based on the behavior of magnetic field lines. In closed-field regions, the magnetic field is firmly anchored in the photosphere at both ends of field lines, so traveling plasma is confined to coronal loops and must return to the Suns surface. In open-field regions, only one end of each magnetic field line is anchored in the photosphere, so plasma is able to stream from the Suns surface out into the <span class="hlt">solar</span> system.This second type of region known as a coronal hole is thought to be the origin of fast-moving plasma measured in our <span class="hlt">solar</span> system and known as the fast <span class="hlt">solar</span> <span class="hlt">wind</span>. But we also observe a slow <span class="hlt">solar</span> <span class="hlt">wind</span>: plasma that moves at speeds of less than 500 km/s.The slow <span class="hlt">solar</span> <span class="hlt">wind</span> presents a conundrum. Its observational properties strongly suggest it originates in the hot, closed corona rather than the cooler, open regions. But if the slow <span class="hlt">solar</span> <span class="hlt">wind</span> plasma originates in closed-field regions of the Suns atmosphere, then how does it escape from the Sun?Slow <span class="hlt">Wind</span> from Closed FieldsA team of scientists led by Aleida Higginson (University of Michigan) has now used high-resolution, three-dimensional magnetohydrodynamic simulations to show how the slow <span class="hlt">solar</span> <span class="hlt">wind</span> can be generated from plasma that starts outin closed-field parts of the Sun.A simulated heliospheric arc, composed of open magnetic field lines. [Higginson et al. 2017]Motions on the Suns surface near the boundary between open and closed-field regions the boundary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6920R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6920R"><span>Origin and Ion Charge State Evolution of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Transients 4 - 7 August 2011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodkin, Denis; Goryaev, Farid; Pagano, Paolo; Gibb, Gordon; Slemzin, Vladimir; Shugay, Yulia; Veselovsky, Igor; Mackay, Duncan</p> <p>2017-04-01</p> <p>Identification of transients and their origins on the Sun is one of the most important problems of the space weather forecasting. In our work, we present a case study of the complex event consisting of several <span class="hlt">solar</span> <span class="hlt">wind</span> transients detected by <span class="hlt">ACE</span> on 4 - 7 August 2011, that caused a geomagnetic storm with Dst= - 110 nT. The supposed coronal sources - three flares and coronal mass ejections (CMEs) occurred on 2 - 4 August 2011 in the active region AR 11261. To investigate the <span class="hlt">solar</span> origins and formation of these transients, we studied kinematic and thermodynamic properties of expanding coronal structures using the SDO/AIA EUV images and the differential emission measure (DEM) diagnostics. The Helioseismic and Magnetic Imager (HMI) magnetic field maps were used as the input data for the 3D numerical model to describe the flux rope ejection. We characterize the early phase of the flux rope ejection in the corona, where the usual three-component CME structure formed. The flux rope ejected with the speed about 200 km/s to the height of 0.25 Rsun. The kinematics of the modeled CME front well agrees with the STEREO EUV measurements. Using the results of the plasma diagnostics and MHD modeling, we calculated the ion charge ratios of carbon and oxygen as well as the mean charge state of iron ions of the 2 August 2011 CME taking into account the processes of heating, cooling, expansion, ionization and recombination of the moving plasma in the corona up to the freeze-in region. We estimated a probable heating rate of the CME plasma in the low corona by matching the calculated ion composition parameters of the CME with that measured in-situ parameters of the <span class="hlt">solar</span> <span class="hlt">wind</span> transients. We also consider the similarities and discrepancies between the results of the MHD simulation and the observation of the event. Our results show that analysis of the ion composition of CMEs enables to disclose a relationship between parameters of the <span class="hlt">solar</span> <span class="hlt">wind</span> transients and properties of their</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021279&hterms=atmosphere+wind+profile&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Datmosphere%2Bwind%2Bprofile','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021279&hterms=atmosphere+wind+profile&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Datmosphere%2Bwind%2Bprofile"><span>Elemental and charge state composition of the fast <span class="hlt">solar</span> <span class="hlt">wind</span> observed with SMS instruments on <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gloeckler, G.; Galvin, A. B.; Ipavich, F. M.; Hamilton, D. C.; Bochsler, P.; Geiss, J.; Fisk, L. A.; Wilken, B.</p> <p>1995-01-01</p> <p>The elemental composition and charge state distributions of heavy ions of the <span class="hlt">solar</span> <span class="hlt">wind</span> provide essential information about: (1) atom-ion separation processes in the <span class="hlt">solar</span> atmosphere leading to the 'FIP effect' (the overabundance of low First Ionization potential (FIP) elements in the <span class="hlt">solar</span> <span class="hlt">wind</span> compared to the photosphere); and (2) coronal temperature profiles, as well as mechanisms which heat the corona and accelerate the <span class="hlt">solar</span> <span class="hlt">wind</span>. This information is required for <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration models. The SWICS instrument on Ulysses measures for all <span class="hlt">solar</span> <span class="hlt">wind</span> flow conditions the relative abundance of about 8 elements and 20 charge states of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Furthermore, the Ulysses high-latitude orbit provides an unprecedented look at the <span class="hlt">solar</span> <span class="hlt">wind</span> from the polar coronal holes near <span class="hlt">solar</span> minimum conditions. The MASS instrument on the <span class="hlt">WIND</span> spacecraft is a high-mass resolution <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> composition in both the slow and the corotating fast streams. This unique combination of SWICS on Ulysses and MASS on <span class="hlt">WIND</span> allows us to view for the first time the <span class="hlt">solar</span> <span class="hlt">wind</span> from two regions of the large coronal hole. Observations with SWICS in the coronal hole <span class="hlt">wind</span>: (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 <span class="hlt">Wind</span> will be compared with results from SWICS on Ulysses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1224824','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/1224824"><span><span class="hlt">Solar</span> energy system with <span class="hlt">wind</span> vane</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Grip, Robert E</p> <p>2015-11-03</p> <p>A <span class="hlt">solar</span> energy system including a pedestal defining a longitudinal axis, a frame that is supported by the pedestal and that is rotateable relative to the pedestal about the longitudinal axis, the frame including at least one <span class="hlt">solar</span> device, and a <span class="hlt">wind</span> vane operatively connected to the frame to urge the frame relative to the pedestal about the longitudinal axis in response to <span class="hlt">wind</span> acting on the <span class="hlt">wind</span> vane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982STIN...8233887E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982STIN...8233887E"><span><span class="hlt">Solar</span>- and <span class="hlt">wind</span>-powered irrigation systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Enochian, R. V.</p> <p>1982-02-01</p> <p>Five different direct <span class="hlt">solar</span> and <span class="hlt">wind</span> 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 <span class="hlt">solar</span> cells prove correct); and <span class="hlt">wind</span> systems, especially in remote areas where adequate <span class="hlt">wind</span> is available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810060080&hterms=Solar+power+filters&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DSolar%2Bpower%2Bfilters','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810060080&hterms=Solar+power+filters&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DSolar%2Bpower%2Bfilters"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> control of auroral zone geomagnetic activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clauer, C. R.; Mcpherron, R. L.; Searls, C.; Kivelson, M. G.</p> <p>1981-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> magnetosphere energy coupling functions are analyzed using linear prediction filtering with 2.5 minute data. The relationship of auroral zone geomagnetic activity to <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> energy functions, although the AU index shows a poor relationship. High frequency variations of auroral indices and substorm expansions are not predictable with <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> dependency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AdSpR..42.1504S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AdSpR..42.1504S"><span>Real-time global MHD simulation of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with the earth’s magnetosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimazu, H.; Kitamura, K.; Tanaka, T.; Fujita, S.; Nakamura, M. S.; Obara, T.</p> <p>2008-11-01</p> <p>We have developed a real-time global MHD (magnetohydrodynamics) simulation of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with the earth’s magnetosphere. By adopting the real-time <span class="hlt">solar</span> <span class="hlt">wind</span> parameters and interplanetary magnetic field (IMF) observed routinely by the <span class="hlt">ACE</span> (Advanced Composition Explorer) spacecraft, responses of the magnetosphere are calculated with MHD code. The simulation is carried out routinely on the super computer system at National Institute of Information and Communications Technology (NICT), Japan. The visualized images of the magnetic field lines around the earth, pressure distribution on the meridian plane, and the conductivity of the polar ionosphere, can be referred to on the web site (http://www2.nict.go.jp/y/y223/simulation/realtime/). The results show that various magnetospheric activities are almost reproduced qualitatively. They also give us information how geomagnetic disturbances develop in the magnetosphere in relation with the ionosphere. From the viewpoint of space weather, the real-time simulation helps us to understand the whole image in the current condition of the magnetosphere. To evaluate the simulation results, we compare the AE indices derived from the simulation and observations. The simulation and observation agree well for quiet days and isolated substorm cases in general.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..12211468M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..12211468M"><span><span class="hlt">Solar</span> Illumination Control of the Polar <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maes, L.; Maggiolo, R.; De Keyser, J.; André, M.; Eriksson, A. I.; Haaland, S.; Li, K.; Poedts, S.</p> <p>2017-11-01</p> <p>Polar <span class="hlt">wind</span> outflow is an important process through which the ionosphere supplies plasma to the magnetosphere. The main source of energy driving the polar <span class="hlt">wind</span> is <span class="hlt">solar</span> illumination of the ionosphere. As a result, many studies have found a relation between polar <span class="hlt">wind</span> flux densities and <span class="hlt">solar</span> EUV intensity, but less is known about their relation to the <span class="hlt">solar</span> 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 <span class="hlt">wind</span> at high altitudes. We take advantage of an alternative method that allows estimations of the polar <span class="hlt">wind</span> 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 <span class="hlt">solar</span> zenith angle in the ion flux density and see that both the ion velocity and density exhibit a <span class="hlt">solar</span> zenith angle dependence as well. We also find a seasonal variation of the flux density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSMSM31B..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSMSM31B..01S"><span>Preparing <span class="hlt">WIND</span> for the STEREO Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schroeder, P.; Ogilve, K.; Szabo, A.; Lin, R.; Luhmann, J.</p> <p>2006-05-01</p> <p>The upcoming STEREO mission's IMPACT and PLASTIC investigations will provide the first opportunity for long duration, detailed observations of 1 AU magnetic field structures, plasma ions and electrons, suprathermal electrons, and energetic particles at points bracketing Earth's heliospheric location. Stereoscopic/3D information from the STEREO SECCHI imagers and SWAVES radio experiment will make it possible to use both multipoint and quadrature studies to connect interplanetary Coronal Mass Ejections (ICME) and <span class="hlt">solar</span> <span class="hlt">wind</span> structures to CMEs and coronal holes observed at the Sun. To fully exploit these unique data sets, tight integration with similarly equipped missions at L1 will be essential, particularly <span class="hlt">WIND</span> and <span class="hlt">ACE</span>. The STEREO mission is building novel data analysis tools to take advantage of the mission's scientific potential. These tools will require reliable access and a well-documented interface to the L1 data sets. Such an interface already exists for <span class="hlt">ACE</span> through the <span class="hlt">ACE</span> Science Center. We plan to provide a similar service for the <span class="hlt">WIND</span> mission that will supplement existing CDAWeb services. Building on tools also being developed for STEREO, we will create a SOAP application program interface (API) which will allow both our STEREO/<span class="hlt">WIND/ACE</span> interactive browser and third-party software to access <span class="hlt">WIND</span> data as a seamless and integral part of the STEREO mission. The API will also allow for more advanced forms of data mining than currently available through other data web services. Access will be provided to <span class="hlt">WIND</span>-specific data analysis software as well. The development of cross-spacecraft data analysis tools will allow a larger scientific community to combine STEREO's unique in-situ data with those of other missions, particularly the L1 missions, and, therefore, to maximize STEREO's scientific potential in gaining a greater understanding of the heliosphere.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22519953-new-horizons-solar-wind-around-pluto-swap-observations-solar-wind-from-au','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22519953-new-horizons-solar-wind-around-pluto-swap-observations-solar-wind-from-au"><span>THE NEW HORIZONS <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> AROUND PLUTO (SWAP) OBSERVATIONS OF THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> FROM 11–33 au</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Elliott, H. A.; McComas, D. J.; Valek, P.</p> <p></p> <p>The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Around Pluto (SWAP) instrument on National Aeronautics and Space Administration's New Horizons Pluto mission has collected <span class="hlt">solar</span> <span class="hlt">wind</span> observations en route from Earth to Pluto, and these observations continue beyond Pluto. Few missions have explored the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> values. These comparisons as well as our additional findings confirm that small and midsized <span class="hlt">solar</span> <span class="hlt">wind</span> structures are worn down with increasing distance due to dynamic interaction of parcels of <span class="hlt">wind</span> 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 <span class="hlt">wind</span> currently expanding and cooling may have an elevated T reflecting prior heating and compression in the inner heliosphere. The power of <span class="hlt">wind</span> parameters at shorter periodicities decreases with distance as the longer periodicities strengthen. The <span class="hlt">solar</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021392&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwind%2Bmonitor','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021392&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwind%2Bmonitor"><span>SWICS/Ulysses and MASS/<span class="hlt">wind</span> observations of <span class="hlt">solar</span> <span class="hlt">wind</span> sulfur charge states</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cohen, C. M. S.; Galvin, A. B.; Hamilton, D. C.; Gloeckler, G.; Geiss, J.; Bochsler, P.</p> <p>1995-01-01</p> <p>As Ulysses journeys from the southern to the northern <span class="hlt">solar</span> pole, the newly launched <span class="hlt">Wind</span> spacecraft is monitoring the <span class="hlt">solar</span> <span class="hlt">wind</span> near 1 AU, slightly upstream of the Earth. Different <span class="hlt">solar</span> <span class="hlt">wind</span> structures pass over both spacecraft as coronal holes and other features rotate in and out of view. Ulysses and <span class="hlt">Wind</span> are presently on opposing sides of the sun allowing us to monitor these streams for extended periods of time. Composition measurements made by instruments on both spacecraft provide information concerning the evolution and properties of these structures. We have combined data from the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer (SWICS) on Ulysses and the high mass resolution spectrometer (MASS) on <span class="hlt">Wind</span> to determine the charge state distribution of sulfur in the <span class="hlt">solar</span> <span class="hlt">wind</span>. Both instruments employ electrostatic deflection with time-of-flight measurement. The high mass resolution of the MASS instrument (M/Delta-M approximately 100) allows sulfur to be isolated easily while the stepping energy/charge selection provides charge state information. SWICS measurements allow the unique identification of heavy ions by their mass and mass/charge with resolutions of M/Delta-M approximately 3 and M/q/Delta(M/q) approximately 20. The two instruments complement each other nicely in that MASS has the greater mass resolution while SWICS has the better mass/charge resolution and better statistics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002084','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002084"><span>The interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the interstellar medium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Axford, W. I.</p> <p>1972-01-01</p> <p>The expected characteristics of the <span class="hlt">solar</span> <span class="hlt">wind</span>, extrapolated from the vicinity of the earth are described. Several models are examined for the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the interstellar plasma and magnetic field. Various aspects of the penetration of neutral interstellar gas into the <span class="hlt">solar</span> <span class="hlt">wind</span> are considered. The dynamic effects of the neutral gas on the <span class="hlt">solar</span> <span class="hlt">wind</span> are described. Problems associated with the interaction of cosmic rays with the <span class="hlt">solar</span> <span class="hlt">wind</span> are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ERL.....9e5004S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ERL.....9e5004S"><span>Evidence for <span class="hlt">solar</span> <span class="hlt">wind</span> modulation of lightning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scott, C. J.; Harrison, R. G.; Owens, M. J.; Lockwood, M.; Barnard, L.</p> <p>2014-05-01</p> <p>The response of lightning rates over Europe to arrival of high speed <span class="hlt">solar</span> <span class="hlt">wind</span> streams at Earth is investigated using a superposed epoch analysis. Fast <span class="hlt">solar</span> <span class="hlt">wind</span> stream arrival is determined from modulation of the <span class="hlt">solar</span> <span class="hlt">wind</span> V y component, measured by the Advanced Composition Explorer spacecraft. Lightning rate changes around these event times are determined from the very low frequency arrival time difference (ATD) system of the UK Met Office. Arrival of high speed streams at Earth is found to be preceded by a decrease in total <span class="hlt">solar</span> irradiance and an increase in sunspot number and Mg II emissions. These are consistent with the high speed stream’s source being co-located with an active region appearing on the Eastern <span class="hlt">solar</span> limb and rotating at the 27 d period of the Sun. Arrival of the high speed stream at Earth also coincides with a small (˜1%) but rapid decrease in galactic cosmic ray flux, a moderate (˜6%) increase in lower energy <span class="hlt">solar</span> energetic protons (SEPs), and a substantial, statistically significant increase in lightning rates. These changes persist for around 40 d in all three quantities. The lightning rate increase is corroborated by an increase in the total number of thunder days observed by UK Met stations, again persisting for around 40 d after the arrival of a high speed <span class="hlt">solar</span> <span class="hlt">wind</span> stream. This result appears to contradict earlier studies that found an anti-correlation between sunspot number and thunder days over <span class="hlt">solar</span> cycle timescales. The increase in lightning rates and thunder days that we observe coincides with an increased flux of SEPs which, while not being detected at ground level, nevertheless penetrate the atmosphere to tropospheric altitudes. This effect could be further amplified by an increase in mean lightning stroke intensity that brings more strokes above the detection threshold of the ATD system. In order to remove any potential seasonal bias the analysis was repeated for daily <span class="hlt">solar</span> <span class="hlt">wind</span> triggers occurring during the summer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040074203','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040074203"><span>Properties of Minor Ions in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Implications for the Background <span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wagner, William (Technical Monitor); Esser, Ruth</p> <p>2004-01-01</p> <p>The scope of the investigation is to extract information on the properties of the bulk <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> radii, hence they carry information on the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> models, coronal observations, and ion calculations in conjunction with the in situ observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ascl.soft05005M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ascl.soft05005M"><span>3DCORE: Forward modeling of <span class="hlt">solar</span> storm magnetic flux ropes for space weather prediction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Möstl, C.; Amerstorfer, T.; Palmerio, E.; Isavnin, A.; Farrugia, C. J.; Lowder, C.; Winslow, R. M.; Donnerer, J. M.; Kilpua, E. K. J.; Boakes, P. D.</p> <p>2018-05-01</p> <p>3DCORE forward models <span class="hlt">solar</span> storm magnetic flux ropes called 3-Dimensional Coronal Rope Ejection (3DCORE). The code is able to produce synthetic in situ observations of the magnetic cores of <span class="hlt">solar</span> coronal mass ejections sweeping over planets and spacecraft. Near Earth, these data are taken currently by the <span class="hlt">Wind</span>, <span class="hlt">ACE</span> and DSCOVR spacecraft. Other suitable spacecraft making these kind of observations carrying magnetometers in the <span class="hlt">solar</span> <span class="hlt">wind</span> were MESSENGER, Venus Express, MAVEN, and even Helios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020044001','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020044001"><span>Properties of Minor Ions In the <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Implications for the Background <span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esser, Ruth; Wagner, William (Technical Monitor)</p> <p>2002-01-01</p> <p>Ion charge states measured in situ in interplanetary space carry information on the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> models, coronal observations, ion fraction calculations and in situ observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021285&hterms=kellogg&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dkellogg','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021285&hterms=kellogg&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dkellogg"><span>Some remarks on waves in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kellogg, Paul J.</p> <p>1995-01-01</p> <p>Waves are significant to the <span class="hlt">solar</span> <span class="hlt">wind</span> in two ways as modifiers of the particle distribution functions, and as diagnostics. In addition, the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> itself. A third area is possibly in maintaining the relative isotropy of the <span class="hlt">solar</span> <span class="hlt">wind</span> ion distribution in the <span class="hlt">solar</span> <span class="hlt">wind</span> rest frame. As the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> Type 111 burst phenomenon, have been extensively studied as examples of nonlinear plasma phenomena, and also used as remote sensors to trace the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> are usually in quasi-thermal equilibrium quasi because the <span class="hlt">solar</span> <span class="hlt">wind</span> itself is not isothermal. The Observatory of Paris group (Steinberg. Meyer-Vernet, Hoang) has exploited this with an experiment on <span class="hlt">WIND</span> which is capable of providing density and temperature on a faster time scale than hitherto. Recently</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9652R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9652R"><span>Comparison of <span class="hlt">solar</span> <span class="hlt">wind</span> driving of the aurora in the two hemispheres due to the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reistad, Jone Peter; Østgaard, Nikolai; Magnus Laundal, Karl; Haaland, Stein; Tenfjord, Paul; Oksavik, Kjellmar</p> <p>2014-05-01</p> <p>Event studies of simultaneous global imaging of the aurora in both hemispheres have suggested that an asymmetry of the <span class="hlt">solar</span> <span class="hlt">wind</span> driving between the two hemispheres could explain observations of non-conjugate aurora during specific driving conditions. North-South asymmetries in energy transfer from the <span class="hlt">solar</span> <span class="hlt">wind</span> across the magnetopause is believed to depend upon the dipole tilt angle and the x-component of the interplanetary magnetic field (IMF). Both negative tilt (winter North) and negative IMF Bx is expected to enhance the efficiency of the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo in the Northern Hemisphere. By the same token, positive tilt and IMF Bx is expected to enhance the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo efficiency in the Southern Hemisphere. We show a statistical study of the auroral response from both hemispheres using global imaging where we compare results during both favourable and not favourable conditions in each hemisphere. By this study we will address the question of general impact on auroral hemispheric asymmetries by this mechanism - the asymmetric <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo. We use data from the Wideband Imaging Camera on the IMAGE spacecraft which during its lifetime from 2000-2005 covered both hemispheres. To ease comparison of the two hemispheres, seasonal differences in auroral brightness is removed as far as data coverage allows by only using events having small dipole tilt angles. Hence, the IMF Bx is expected to be the controlling parameter for the hemispheric preference of strongest <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo efficiency in our dataset. Preliminary statistical results indicate the expected opposite behaviour in the two hemispheres, however, the effect is believed to be weak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820028333&hterms=1087&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231087','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820028333&hterms=1087&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231087"><span>Correlations between <span class="hlt">solar</span> <span class="hlt">wind</span> parameters and auroral kilometric radiation intensity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gallagher, D. L.; Dangelo, N.</p> <p>1981-01-01</p> <p>The relationship between <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> data from the composite <span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma Data Set, most of which was supplied by the IMP-8 spacecraft. Correlations are made between smoothed daily averages of <span class="hlt">solar</span> <span class="hlt">wind</span> ion density, bulk flow speed, total IMF strength, electric field, <span class="hlt">solar</span> <span class="hlt">wind</span> speed in the southward direction, <span class="hlt">solar</span> <span class="hlt">wind</span> speed multiplied by total IMF strength, the substorm parameter epsilon and the Kp index. The greatest correlation is found between <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860040981&hterms=relationship+form&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drelationship%2Bform','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860040981&hterms=relationship+form&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drelationship%2Bform"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> proton temperature-velocity relationship</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, R. E.; Freeman, J. W.</p> <p>1986-01-01</p> <p>Helios 1 data are analyzed to find an experimental fit for the temperature-velocity relationship at 1 AU. It is shown that the proton temperature-velocity changes at a velocity of approximately 500 km/s. Interplanetary dynamic processes, i.e., stream interactions, are shown to affect the temperature-velocity relationships less than 22 percent; the functional form of these relationships appears to be preserved throughout the <span class="hlt">solar</span> cycle. It is pointed out that any comprehensive model of the <span class="hlt">solar</span> <span class="hlt">wind</span> will have to address the difference in the temperature-velocity relationship between the low- and high-speed <span class="hlt">wind</span>, since this is a product of the acceleration and subsequent heating process generating the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3774C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3774C"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> proton density increase that preceded Central Italy earthquakes occurred between 26 and 30 October 2016</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino</p> <p>2017-04-01</p> <p>Between 26 and 30 October 2016 in Central Italy were recorded two strong earthquakes: M6.1 occurred on October 26, 2016 at 19:18:08 UTC and M6.6 occurred on October 30, 2016 at 06:40:18 UTC. The authors of this study noted that the two earthquakes were preceded by an increase in the proton density of the interplanetary medium: a phenomenon observed since 2012 and has always preceded the seismic events of high intensity (M6+) occurring on a global scale. To obtain these results the authors have analyzed the conditions of Spaceweather "near Earth" and the characteristics of the Earth's geomagnetic field in the days and in the hours that preceded the two earthquakes. The data relating to the two earthquakes were provided by the United States Geological Survey (USGS). The data on ion density used to realize the study are represented by: <span class="hlt">solar</span> <span class="hlt">wind</span> ion density variation detected by <span class="hlt">ACE</span> (Advanced Composition Explorer) Satellite, in orbit near the L1 Lagrange point, at 1.5 million of km from Earth, in direction of the Sun. The instrument used to perform the measurement of the <span class="hlt">solar</span> <span class="hlt">wind</span> ion density is the Electron, Proton, and Alpha Monitor (EPAM) instrument, equipped on the <span class="hlt">ACE</span> Satellite. To conduct the study, the authors have taken in consideration the variation of the <span class="hlt">solar</span> <span class="hlt">wind</span> protons density of three different energy fractions: differential proton flux 1060-1900 keV (p/cm^2-sec-ster-MeV); differential proton flux 761-1220 keV (p/cm^2-sec-ster-MeV); differential proton flux 310-580 keV (p/cm^2-sec-ster-MeV). In addition, the authors were analyzed the Earth's geomagnetic field variations through the geomagnetic data released by Tromsø Geomagnetic Observatory (TGO), Norway; Scoresbysund Geomagnetic Observatory (SCO), Greenland, Denmark; Dikson Geomagnetic Observatory (DIK), Russia and Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation (IZMIRAN), Troitsk, Moscow Region. The results of the study, in agreement with what already ascertained</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780039623&hterms=orbiting+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dorbiting%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780039623&hterms=orbiting+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dorbiting%2Bwind"><span>Ion acoustic waves in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gurnett, D. A.; Frank, L. A.</p> <p>1978-01-01</p> <p>Plasma wave measurements on the Helios 1 and 2 spacecraft have revealed the occurrence of electric field turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> at frequencies between the electron and ion plasma frequencies. Wavelength measurements with the Imp 6 spacecraft now provide strong evidence that these waves are shortwavelength ion acoustic waves which are Doppler-shifted upward in frequency by the motion of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Comparison of the Helios results with measurements from the earth-orbiting Imp 6 and 8 spacecraft shows that the ion acoustic wave turbulence detected in interplanetary space has characteristics essentially identical to those of bursts of electrostatic turbulence generated by protons streaming into the <span class="hlt">solar</span> <span class="hlt">wind</span> from the earth's bow shock. In a few cases, enhanced ion acoustic wave intensities have been observed in direct association with abrupt increases in the anisotropy of the <span class="hlt">solar</span> <span class="hlt">wind</span> electron distribution. This relationship strongly suggests that the ion acoustic waves detected by Helios far from the earth are produced by an electron heat flux instability, as was suggested by Forslund. Possible related mechanisms which could explain the generation of ion acoustic waves by protons streaming into the <span class="hlt">solar</span> <span class="hlt">wind</span> from the earth's bow shock are also considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110003574','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110003574"><span>Carbon Dioxide (CO2) Retrievals from Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>) <span class="hlt">Solar</span> Occultation Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rinsland, Curtis P.; Chiou, Linda; Boone, Chris; Bernath, Peter</p> <p>2010-01-01</p> <p>The Atmospheric Chemistry Experiment <span class="hlt">ACE</span> satellite (SCISAT-1) was launched into an inclined orbit on 12 August 2003 and is now recording high signal-to-noise 0.02 per centimeter resolution <span class="hlt">solar</span> absorption spectra covering 750-4400 per centimeter (2.3-13 micrometers). A procedure has been developed for retrieving average dry air CO2 mole fractions (X(sub CO2)) in the altitude range 7-10 kilometers from the SCISAT-1 spectra. Using the N2 continuum absorption in a window region near 2500 per centimeter, altitude shifts are applied to the tangent heights retrieved in version 2.2 SCISAT-1 processing, while cloudy or aerosol-impacted measurements are eliminated. Monthly-mean XCO2 covering 60 S to 60 N latitude for February 2004 to March 2008 has been analyzed with consistent trends inferred in both hemispheres. The <span class="hlt">ACE</span> XCO2 time series have been compared with previously-reported surface network measurements, predictions based on upper tropospheric aircraft measurements, and space-based measurements. The retrieved X(sub CO2) from the <span class="hlt">ACE</span>-FTS spectra are higher on average by a factor of 1.07 plus or minus 0.025 in the northern hemisphere and by a factor of 1.09 plus or minus 0.019 on average in the southern hemisphere compared to surface station measurements covering the same time span. The <span class="hlt">ACE</span> derived trend is approximately 0.2% per year higher than measured at surface stations during the same observation period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930049592&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930049592&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3Dlazarus"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> temperature observations in the outer heliosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.</p> <p>1992-01-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. The <span class="hlt">solar</span> <span class="hlt">wind</span> temperature decreases with increasing heliocentric distance out to a distance of 10-15 AU. At larger heliocentric distances, this gradient disappears. These high <span class="hlt">solar</span> <span class="hlt">wind</span> temperatures in the outer heliosphere have persisted for at least 10 years, which suggests that they are not a <span class="hlt">solar</span> cycle effect. The <span class="hlt">solar</span> <span class="hlt">wind</span> temperature varied with heliographic latitude during the most recent <span class="hlt">solar</span> minimum. The <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030020816&hterms=background+wind&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbackground%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030020816&hterms=background+wind&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbackground%2Bwind"><span>Properties of Minor Ions in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Implications for the Background <span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esser, Ruth; Wagner, William (Technical Monitor)</p> <p>2003-01-01</p> <p>Ion charge states measured in situ in interplanetary space are formed in the inner coronal regions below 5 <span class="hlt">solar</span> radii, hence they carry information on the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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. The goal of the proposal is to make use of ion fractions observed in situ in the <span class="hlt">solar</span> <span class="hlt">wind</span> to learn about both, the plasma conditions in the inner corona and the expansion and ion formation itself. This study is carried out using <span class="hlt">solar</span> <span class="hlt">wind</span> models, coronal observations, and ion fraction calculations in conjunction with the in situ observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930049627&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dbackground%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930049627&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dbackground%2Bwind"><span>Ions with low charges in the <span class="hlt">solar</span> <span class="hlt">wind</span> as measured by SWICS on board Ulysses. [<span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Geiss, J.; Ogilvie, K. W.; Von Steiger, R.; Mall, U.; Gloeckler, G.; Galvin, A. B.; Ipavich, F.; Wilken, B.; Gliem, F.</p> <p>1992-01-01</p> <p>We present new data on rare ions in the <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and established sensitive upper limits for many species. In the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span> sample we studied. Since this sample showed the FlP effect typical for low-speed <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> surface and not by foreign material in the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM11B2315M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM11B2315M"><span>Time-lag and Correlation between <span class="hlt">ACE</span> and RBSPICE Injection Event Observations during Storm Times</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Madanian, H.; Patterson, J. D.; Manweiler, J. W.; Soto-chavez, A. R.; Gerrard, A. J.; Lanzerotti, L. J.</p> <p>2017-12-01</p> <p>The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on the Van Allen Probes mission measures energetic charged particles [ 20 keV to 1 MeV] in the inner magnetosphere and ring current. During geomagnetic storms, injections of energetic ions into the ring current change the ion population and produce geomagnetic field depressions on Earth's surface. We analyzed the magnetic field strength and particle composition in the interplanetary medium measured by instruments on the Advanced Composition Explorer (<span class="hlt">ACE</span>) spacecraft near the inner Lagrangian point. The Electron, Proton, and Alpha Monitor-Low Energy Magnetic Spectrometer (EPAM-LEMS) sensor on <span class="hlt">ACE</span> measures energetic particles [ 50 keV to 5 MeV] in the interplanetary space. The SYM-H index is utilized to classify the storm events by magnitude and to select more than 60 storm events between 2013 and 2017. We cross-compared <span class="hlt">ACE</span> observations at storm times, with the RBSPICE ion measurements at dusk to midnight magnetic local time and over the 3-6 L-shell range. We report on the relative composition of the <span class="hlt">solar</span> particles and the relative composition of the inner magnetospheric hot plasma during storm times. The data correlation is accomplished by shifting the observation time from <span class="hlt">ACE</span> to RBSPICE using the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity at the time of the observation. We will discuss time lags between storm onset at the magnetopause and injection events measured for each storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080045448&hterms=terminator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dterminator','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080045448&hterms=terminator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dterminator"><span>Neutral <span class="hlt">Solar</span> <span class="hlt">Wind</span> Generated by Lunar Exospheric Dust at the Terminator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Collier, Michael R.; Stubbs, Timothy J.</p> <p>2007-01-01</p> <p>We calculate the flux of neutral <span class="hlt">solar</span> <span class="hlt">wind</span> observed on the lunar surface at the terminator due to <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> to <span class="hlt">solar</span> <span class="hlt">wind</span> flux is estimated to be approx.10(exp -4)-10(exp -3) at <span class="hlt">solar</span> <span class="hlt">wind</span> speeds in excess of 800 km/s, but much lower (less than 10(exp -5) at average to low <span class="hlt">solar</span> <span class="hlt">wind</span> speeds. However, when the smaller grain sizes are considered, the ratio of the neutral <span class="hlt">solar</span> <span class="hlt">wind</span> flux to <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> fluxes are easily measurable with current low energy neutral atom instrumentation. Observations of neutral <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, unlike its ionized counterpart, is .not held-off by magnetic anomalies, and may contribute to greater space weathering than expected in certain lunar locations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770032937&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dwind%2Bmonitor','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770032937&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dwind%2Bmonitor"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> and extreme ultraviolet modulation of the lunar ionosphere/exosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freeman, J. W.</p> <p>1976-01-01</p> <p>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 <span class="hlt">solar</span> EUV and with the <span class="hlt">solar</span> <span class="hlt">wind</span> proton flux. For the <span class="hlt">solar</span> <span class="hlt">wind</span>, the ionospheric variation is proportionately greater than that of the <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. The surface neutral number density is calculated under the assumption of neon gas. During a quiet <span class="hlt">solar</span> <span class="hlt">wind</span> this number agrees with or is slightly above that expected for neon accreted from the <span class="hlt">solar</span> <span class="hlt">wind</span>. During an enhanced <span class="hlt">solar</span> <span class="hlt">wind</span> the neutral number density is much higher.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830052897&hterms=ACCOUNTS+CHARGE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DACCOUNTS%2BBY%2BCHARGE','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830052897&hterms=ACCOUNTS+CHARGE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DACCOUNTS%2BBY%2BCHARGE"><span>Charge exchange in <span class="hlt">solar</span> <span class="hlt">wind</span>-cometary interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gombosi, T. I.; Horanyi, M.; Kecskemety, K.; Cravens, T. E.; Nagy, A. F.</p> <p>1983-01-01</p> <p>A simple model of a cometary spherically symmetrical atmosphere and ionosphere is considered. An analytic solution of the governing equations describing the radial distribution of the neutral and ion densities is found. The new solution is compared to the well-known solution of the equations containing only ionization terms. Neglecting recombination causes a significant overestimate of the ion density in the vicinity of the comet. An axisymmetric model of the <span class="hlt">solar</span> <span class="hlt">wind</span>-cometary interaction is considered, taking into account the loss of <span class="hlt">solar</span> <span class="hlt">wind</span> ions due to charge exchange. The calculations predict that for active comets, <span class="hlt">solar</span> <span class="hlt">wind</span> absorption due to charge exchange becomes important at a few thousand kilometers from the nucleus, and a surface separating the shocked <span class="hlt">solar</span> <span class="hlt">wind</span> from the cometary ionosphere develops in this region. These calculations are in reasonable agreement with the few observations available for the ionopause location at comets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvE..89e2812M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvE..89e2812M"><span>Stationarity of extreme bursts in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moloney, N. R.; Davidsen, J.</p> <p>2014-05-01</p> <p>Recent results have suggested that the statistics of bursts in the <span class="hlt">solar</span> <span class="hlt">wind</span> vary with <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> ɛ parameter and similar observables are independent of the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> flares and, thus, provides evidence in favor of a link between <span class="hlt">solar</span> flares and extreme bursts in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160002412','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160002412"><span>Genesis <span class="hlt">Solar</span> <span class="hlt">Wind</span> Science Canister Components Curated as Potential <span class="hlt">Solar</span> <span class="hlt">Wind</span> Collectors and Reference Contamination Sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allton, J. H.; Gonzalez, C. P.; Allums, K. K.</p> <p>2016-01-01</p> <p>The Genesis mission collected <span class="hlt">solar</span> <span class="hlt">wind</span> for 27 months at Earth-Sun L1 on both passive and active collectors carried inside of a Science Canister, which was cleaned and assembled in an ISO Class 4 cleanroom prior to launch. The primary passive collectors, 271 individual hexagons and 30 half-hexagons of semiconductor materials, are described in. Since the hard landing reduced the 301 passive collectors to many thousand smaller fragments, characterization and posting in the online catalog remains a work in progress, with about 19% of the total area characterized to date. Other passive collectors, surfaces of opportunity, have been added to the online catalog. For species needing to be concentrated for precise measurement (e.g. oxygen and nitrogen isotopes) an energy-independent parabolic ion mirror focused ions onto a 6.2 cm diameter target. The target materials, as recovered after landing, are described in. The online catalog of these <span class="hlt">solar</span> <span class="hlt">wind</span> collectors, a work in progress, can be found at: http://curator.jsc.nasa.gov/gencatalog/index.cfm This paper describes the next step, the cataloging of pieces of the Science Canister, which were surfaces exposed to the <span class="hlt">solar</span> <span class="hlt">wind</span> or component materials adjacent to <span class="hlt">solar</span> <span class="hlt">wind</span> collectors which may have contributed contamination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SoPh..291.3777L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SoPh..291.3777L"><span>A Possible Cause of the Diminished <span class="hlt">Solar</span> <span class="hlt">Wind</span> During the <span class="hlt">Solar</span> Cycle 23 - 24 Minimum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liou, Kan; Wu, Chin-Chun</p> <p>2016-12-01</p> <p>Interplanetary magnetic field and <span class="hlt">solar</span> <span class="hlt">wind</span> plasma density observed at 1 AU during <span class="hlt">Solar</span> Cycle 23 - 24 (SC-23/24) minimum were significantly smaller than those during its previous <span class="hlt">solar</span> cycle (SC-22/23) minimum. Because the Earth's orbit is embedded in the slow <span class="hlt">wind</span> during <span class="hlt">solar</span> minimum, changes in the geometry and/or content of the slow <span class="hlt">wind</span> region (SWR) can have a direct influence on the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters near the Earth. In this study, we analyze <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and magnetic field data of hourly values acquired by Ulysses. It is found that the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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°) <span class="hlt">solar</span> orbit. The observed latitudinal increase in the SWR is sufficient to explain the excessive decline in the near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> density during the recent <span class="hlt">solar</span> minimum without speculating that the total <span class="hlt">solar</span> output may have been decreasing. The observed SWR inflation is also consistent with a cooler <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SoSyR..51..165O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SoSyR..51..165O"><span>On the history of the <span class="hlt">solar</span> <span class="hlt">wind</span> discovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Obridko, V. N.; Vaisberg, O. L.</p> <p>2017-03-01</p> <p>The discovery of the <span class="hlt">solar</span> <span class="hlt">wind</span> has been an outstanding achievement in heliophysics and space physics. The <span class="hlt">solar</span> <span class="hlt">wind</span> plays a crucial role in the processes taking place in the <span class="hlt">Solar</span> System. In recent decades, it has been recognized as the main factor that controls the terrestrial effects of space weather. The <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, as we know it today, almost "with the point of his pen". In 2017, we will celebrate the 90th anniversary birthday of Eugene Parker.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029599&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D50%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029599&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D50%26Ntt%3Dlazarus"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> velocity and temperature in the outer heliosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.</p> <p>1994-01-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> in the outer heliosphere. The averaged <span class="hlt">solar</span> <span class="hlt">wind</span> speed continued to exhibit its well-known variation with <span class="hlt">solar</span> cycle: Even at heliocentric distances greater than 50 AU, the average speed is highest during the declining phase of the <span class="hlt">solar</span> cycle and lowest near <span class="hlt">solar</span> minimum. There was a strong latitudinal gradient in <span class="hlt">solar</span> <span class="hlt">wind</span> speed between 3 deg and 17 deg N during the last <span class="hlt">solar</span> minimum, but this gradient has since disappeared. The <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> temperatures were higher near <span class="hlt">solar</span> minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..MARV31015P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..MARV31015P"><span>Analysis of <span class="hlt">Wind</span> Forces on Roof-Top <span class="hlt">Solar</span> Panel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panta, Yogendra; Kudav, Ganesh</p> <p>2011-03-01</p> <p>Structural loads on <span class="hlt">solar</span> panels include forces due to high <span class="hlt">wind</span>, gravity, thermal expansion, and earthquakes. International Building Code (IBC) and the American Society of Civil Engineers are two commonly used approaches in <span class="hlt">solar</span> industries to address <span class="hlt">wind</span> loads. Minimum Design Loads for Buildings and Other Structures (ASCE 7-02) can be used to calculate <span class="hlt">wind</span> uplift loads on roof-mounted <span class="hlt">solar</span> panels. The present study is primarily focused on 2D and 3D modeling with steady, and turbulent flow over an inclined <span class="hlt">solar</span> panel on the flat based roof to predict the <span class="hlt">wind</span> forces for designing <span class="hlt">wind</span> 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 <span class="hlt">wind</span> tunnel experiments with a good agreement. <span class="hlt">Solar</span> panels with various aspect ratios for various high <span class="hlt">wind</span> speeds and angle of attacks were modeled and simulated in order to predict the <span class="hlt">wind</span> loads in various scenarios. The present study concluded to reduce the strong <span class="hlt">wind</span> 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).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM54A..08I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM54A..08I"><span>Application of data assimilation to <span class="hlt">solar</span> <span class="hlt">wind</span> forecasting models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Innocenti, M.; Lapenta, G.; Vrsnak, B.; Temmer, M.; Veronig, A.; Bettarini, L.; Lee, E.; Markidis, S.; Skender, M.; Crespon, F.; Skandrani, C.; Soteria Space-Weather Forecast; Data Assimilation Team</p> <p>2010-12-01</p> <p>Data Assimilation through Kalman filtering [1,2] is a powerful statistical tool which allows to combine modeling and observations to increase the degree of knowledge of a given system. We apply this technique to the forecast of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters (proton speed, proton temperature, absolute value of the magnetic field and proton density) at 1 AU, using the model described in [3] and <span class="hlt">ACE</span> data as observations. The model, which relies on GOES 12 observations of the percentage of the meridional slice of the sun covered by coronal holes, grants 1-day and 6-hours in advance forecasts of the aforementioned quantities in quiet times (CMEs are not taken into account) during the declining phase of the <span class="hlt">solar</span> cycle and is tailored for specific time intervals. We show that the application of data assimilation generally improves the quality of the forecasts during quiet times and, more notably, extends the periods of applicability of the model, which can now provide reliable forecasts also in presence of CMEs and for periods other than the ones it was designed for. Acknowledgement: The research leading to these results has received funding from the European Commission’s Seventh Framework Programme (FP7/2007-2013) under the grant agreement N. 218816 (SOTERIA project: http://www.soteria-space.eu). References: [1] R. Kalman, J. Basic Eng. 82, 35 (1960); [2] G. Welch and G. Bishop, Technical Report TR 95-041, University of North Carolina, Department of Computer Science (2001); [3] B. Vrsnak, M. Temmer, and A. Veronig, <span class="hlt">Solar</span> Phys. 240, 315 (2007).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT........77L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT........77L"><span>The structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the inner heliosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Christina On-Yee</p> <p>2010-12-01</p> <p>This dissertation is devoted to expanding our understanding of the <span class="hlt">solar</span> <span class="hlt">wind</span> structure in the inner heliosphere and variations therein with <span class="hlt">solar</span> activity. Using spacecraft observations and numerical models, the origins of the large-scale structures and long-term trends of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> density, velocity, interplanetary magnetic field, and particles, together with models based on <span class="hlt">solar</span> magnetic field data, to generate time series of these properties that span one <span class="hlt">solar</span> rotation (˜27 days). From these time series, I assemble and obtain the synoptic overviews of the <span class="hlt">solar</span> <span class="hlt">wind</span> properties. The resulting synoptic overviews show that the <span class="hlt">solar</span> <span class="hlt">wind</span> around Mercury, Venus, Earth, and Mars is a complex co-rotating structure with recurring features and occasional transients. During quiet <span class="hlt">solar</span> 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 <span class="hlt">solar</span> rotations. Within the sector boundaries are the slow and fast speed <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> period. The existence of these recurring features depends on how long-lived are their source regions. In the last decade, 3D numerical <span class="hlt">solar</span> <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.6150H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.6150H"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> controls on Mercury's magnetospheric cusp</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Maosheng; Vogt, Joachim; Heyner, Daniel; Zhong, Jun</p> <p>2017-06-01</p> <p>This study assesses the response of the cusp to <span class="hlt">solar</span> <span class="hlt">wind</span> changes comprehensively, using 2848 orbits of MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) observation. The assessment entails four steps: (1) propose and validate an approach to estimate the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field (interplanetary magnetic field (IMF)) for MESSENGER's cusp transit; (2) define an index σ measuring the intensity of the magnetic disturbance which significantly peaks within the cusp and serves as an indicator of the cusp activity level; (3) construct an empirical model of σ as a function of IMF and Mercury's heliocentric distance rsun, through linear regression; and (4) use the model to estimate and compare the polar distribution of the disturbance σ under different conditions for a systematic comparison. The comparison illustrates that the disturbance peak over the cusp is strongest and widest extending in local time for negative IMF Bx and negative IMF Bz, and when Mercury is around the perihelion. Azimuthal shifts are associated with both IMF By and rsun: the cusp moves toward dawn when IMF By or rsun decrease. These dependences are explained in terms of the IMF Bx-controlled dayside magnetospheric topology, the component reconnection model applied to IMF By and Bz, and the variability of <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure associated with heliocentric distance rsun. The applicability of the component reconnection model on IMF By indicates that at Mercury reconnection occurs at lower shear angles than at Earth.<abstract type="synopsis"><title type="main">Plain Language SummaryMercury's magnetosphere was suggested to be particularly sensitive to <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. This study investigates the response of the magnetospheric cusp to <span class="hlt">solar</span> <span class="hlt">wind</span> conditions systematically. For this purpose, we analyze the statistical predictability of interplanetary magnetic field (IMF) at Mercury, develop an approach for estimating the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field (IMF) for MErcury Surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870052836&hterms=wind+monitor&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwind%2Bmonitor','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870052836&hterms=wind+monitor&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwind%2Bmonitor"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> parameters and magnetospheric coupling studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, Joseph H.</p> <p>1986-01-01</p> <p>This paper presents distributions, means, and standard deviations of the fluxes of <span class="hlt">solar</span> <span class="hlt">wind</span> protons, momentum, and energy as observed near earth during the <span class="hlt">solar</span> quiet and active years 1976 and 1979. Distributions of ratios of energies (Alfven Mach number, plasma beta) and distributions of interplanetary magnetic field orientations are also given. Finally, the uncertainties associated with the use of the libration point orbiting ISEE-3 spacecraft as a <span class="hlt">solar</span> <span class="hlt">wind</span> monitor are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040111086','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040111086"><span>Simulations of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma Flow Around a Simple <span class="hlt">Solar</span> Sail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garrett, Henry B.; Wang, Joseph</p> <p>2004-01-01</p> <p>In recent years, a number of <span class="hlt">solar</span> sail missions of various designs and sizes have been proposed (e.g., Geostorm). Of importance to these missions is the interaction between the ambient <span class="hlt">solar</span> <span class="hlt">wind</span> plasma environment and the sail. Assuming a typical 1 AU <span class="hlt">solar</span> <span class="hlt">wind</span> environment of 400 km/s velocity, 3.5 cu cm density, ion temperature of approx.10 eV, electron temperature of 40 eV, and an ambient magnetic field strength of 10(exp -4) G, a first order estimate of the plasma interaction with square <span class="hlt">solar</span> sails on the order of the sizes being considered for a Geostorm mission (50 m x 50 m and 75 m x 75 m corresponding to approx.2 and approx.3 times the Debye length in the plasma) is carried out. First, a crude current balance for the sail surface immersed in the plasma environment and in sunlight was used to estimate the surface potential of the model sails. This gave surface potentials of approx.10 V positive relative to the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma. A 3-D, Electrostatic Particle-in-Cell (PIC) code was then used to simulate the <span class="hlt">solar</span> <span class="hlt">wind</span> flowing around the <span class="hlt">solar</span> sail. It is assumed in the code that the <span class="hlt">solar</span> <span class="hlt">wind</span> protons can be treated as particles while the electrons follow a Boltzmann distribution. Next, the electric field and particle trajectories are solved self-consistently to give the proton flow field, the electrostatic field around the sail, and the plasma density in 3-D. The model sail was found to be surrounded by a plasma sheath within which the potential is positive compared to the ambient plasma and followed by a separate plasma wake which is negative relative to the plasma. This structure departs dramatically from a negatively charged plate such as might be found in the Earth s ionosphere on the night side where both the plate and its negative wake are contiguous. The implications of these findings are discussed as they apply to the proposed Geostorm <span class="hlt">solar</span> sail mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002049','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002049"><span>Average thermal characteristics of <span class="hlt">solar</span> <span class="hlt">wind</span> electrons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Montgomery, M. D.</p> <p>1972-01-01</p> <p>Average <span class="hlt">solar</span> <span class="hlt">wind</span> electron properties based on a 1 year Vela 4 data sample-from May 1967 to May 1968 are presented. Frequency distributions of electron-to-ion temperature ratio, electron thermal anisotropy, and thermal energy flux are presented. The resulting evidence concerning heat transport in the <span class="hlt">solar</span> <span class="hlt">wind</span> is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1215020','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1215020"><span>Role of Concentrating <span class="hlt">Solar</span> Power in Integrating <span class="hlt">Solar</span> and <span class="hlt">Wind</span> Energy: Preprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Denholm, P.; Mehos, M.</p> <p>2015-06-03</p> <p>As <span class="hlt">wind</span> and <span class="hlt">solar</span> photovoltaics (PV) increase in penetration it is increasingly important to examine enabling technologies that can help integrate these resources at large scale. Concentrating <span class="hlt">solar</span> power (CSP) when deployed with thermal energy storage (TES) can provide multiple services that can help integrate variable generation (VG) resources such as <span class="hlt">wind</span> 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 <span class="hlt">wind</span>, substantially increasing their penetration in locations with adequate <span class="hlt">solar</span> resource.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SSRv..195..125H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SSRv..195..125H"><span>The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Analyzer for MAVEN</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Halekas, J. S.; Taylor, E. R.; Dalton, G.; Johnson, G.; Curtis, D. W.; McFadden, J. P.; Mitchell, D. L.; Lin, R. P.; Jakosky, B. M.</p> <p>2015-12-01</p> <p>The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Analyzer (SWIA) on the MAVEN mission will measure the <span class="hlt">solar</span> <span class="hlt">wind</span> ion flows around Mars, both in the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> and in the magneto-sheath and tail regions inside the bow shock. The <span class="hlt">solar</span> <span class="hlt">wind</span> flux provides one of the key energy inputs that can drive atmospheric escape from the Martian system, as well as in part controlling the structure of the magnetosphere through which non-thermal ion escape must take place. SWIA measurements contribute to the top level MAVEN goals of characterizing the upper atmosphere and the processes that operate there, and parameterizing the escape of atmospheric gases to extrapolate the total loss to space throughout Mars' history. To accomplish these goals, SWIA utilizes a toroidal energy analyzer with electrostatic deflectors to provide a broad 360∘×90∘ field of view on a 3-axis spacecraft, with a mechanical attenuator to enable a very high dynamic range. SWIA provides high cadence measurements of ion velocity distributions with high energy resolution (14.5 %) and angular resolution (3.75∘×4.5∘ in the sunward direction, 22.5∘×22.5∘ elsewhere), and a broad energy range of 5 eV to 25 keV. Onboard computation of bulk moments and energy spectra enable measurements of the basic properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> at 0.25 Hz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH23C2675C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH23C2675C"><span>Intermittency Statistics in the Expanding <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cuesta, M. E.; Parashar, T. N.; Matthaeus, W. H.</p> <p>2017-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> is observed to be turbulent. One of the open questions in <span class="hlt">solar</span> <span class="hlt">wind</span> research is how the turbulence evolves as the <span class="hlt">solar</span> <span class="hlt">wind</span> expands to great distances. Some studies have focused on evolution of the outer scale but not much has been done to understand how intermittency evolves in the expanding <span class="hlt">wind</span> beyond 1 AU (see [1,2]). We use magnetic field data from Voyager I spacecraft from 1 to 10AU to study the evolution of statistics of magnetic discontinuities. We perform various statistical tests on these discontinuities and make connections to the physical processes occurring in the expanding <span class="hlt">wind</span>.[1] Tsurutani, Bruce T., and Edward J. Smith. "Interplanetary discontinuities: Temporal variations and the radial gradient from 1 to 8.5 AU." Journal of Geophysical Research: Space Physics 84.A6 (1979): 2773-2787.[2] Greco, A., et al. "Evidence for nonlinear development of magnetohydrodynamic scale intermittency in the inner heliosphere." The Astrophysical Journal 749.2 (2012): 105.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1326077-modeling-solar-wind-boundary-conditions-from-interplanetary-scintillations','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1326077-modeling-solar-wind-boundary-conditions-from-interplanetary-scintillations"><span>Modeling <span class="hlt">solar</span> <span class="hlt">wind</span> with boundary conditions from interplanetary scintillations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Manoharan, P.; Kim, T.; Pogorelov, N. V.; ...</p> <p>2015-09-30</p> <p>Interplanetary scintillations make it possible to create three-dimensional, time- dependent distributions of the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity. Combined with the magnetic field observations in the <span class="hlt">solar</span> photosphere, they help perform <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> flow from 0.1 AUmore » to 1 AU with the boundary conditions based on both Ooty and WSA data.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A41O..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A41O..04B"><span>The Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>): Status and Latest Results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bernath, P. F.; Boone, C. D.; McElroy, C. T.</p> <p>2017-12-01</p> <p><span class="hlt">ACE</span> (also known as SCISAT) is making a comprehensive set of simultaneous measurements of numerous trace gases, thin clouds, aerosols and temperature by <span class="hlt">solar</span> occultation from a satellite in low earth orbit. A high inclination (74°) orbit gives <span class="hlt">ACE</span> coverage of tropical, mid-latitudes and polar regions. The primary instrument is a high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating in the 750-4400 cm-1 region, which provides the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. A second instrument, a dual spectrophotometer called MAESTRO, extends the wavelength coverage to the 400-1000 nm spectral region. Aerosols and clouds are being monitored through the extinction of <span class="hlt">solar</span> radiation using two filtered imagers and by MAESTRO as well as by their infrared spectra. After 14 years in orbit, the <span class="hlt">ACE</span> is still operating well. A short overview of the <span class="hlt">ACE</span> mission will be presented (see http://www.<span class="hlt">ace</span>.uwaterloo.ca for more information). The current version (v. 3.5/3.6) of <span class="hlt">ACE</span>-FTS processing includes more than 30 molecules and twenty isotopologues; v.3.5/3.6 is now available in near-real time. This talk will focus on recent <span class="hlt">ACE</span> results and the new version 4.0 of <span class="hlt">ACE</span>-FTS processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110015175','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110015175"><span>Sputtering by the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Effects of Variable Composition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Killen, R. M.; Arrell, W. M.; Sarantos, M.; Delory, G. T.</p> <p>2011-01-01</p> <p>It has long been recognized that <span class="hlt">solar</span> <span class="hlt">wind</span> bombardment onto exposed surfaces in the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> composition have become available. It is now known that the <span class="hlt">solar</span> <span class="hlt">wind</span> composition is highly dependent on the origin of the particular plasma. Using the measured composition of the slow <span class="hlt">wind</span>, fast <span class="hlt">wind</span>, <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.2973B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.2973B"><span>Substorm occurrence rates, substorm recurrence times, and <span class="hlt">solar</span> <span class="hlt">wind</span> structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borovsky, Joseph E.; Yakymenko, Kateryna</p> <p>2017-03-01</p> <p>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 <span class="hlt">solar</span> cycle, the season of the year, the Russell-McPherron favorability, the type of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma at Earth, the geomagnetic-activity level, and as functions of various <span class="hlt">solar</span> and <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> driving interval to occur, (2) the mesoscale structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field triggers the occurrence of the random substorms, and (3) the large-scale structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> is high, when the magnetic field strength of the <span class="hlt">solar</span> <span class="hlt">wind</span> is strong, when the Mach number of the <span class="hlt">solar</span> <span class="hlt">wind</span> is low, and when the polar-cap potential saturation parameter is high.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.1628L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.1628L"><span>Flow Sources of The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Stream Structieres</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V.</p> <p></p> <p>The large-scale stream structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow was studied at the main acceler- ation area of 10 to 40 <span class="hlt">solar</span> radii from the Sun. Three independent sets of experimental data were used: radio astronomy observations of radio wave scattering on near-<span class="hlt">solar</span> plasmas (large radio telescopes of the P.N.Lebedev Physical Institute were used); mor- phology of the WLC as revealed by the SOHO optical <span class="hlt">solar</span> corona observations; <span class="hlt">solar</span> magnetic field strength and configuration computed using the Wilcox <span class="hlt">Solar</span> Observa- tory data. Experimental data of 1997-1998 years on the position of the transition, tran- sonic region of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow were used as a parameter reflecting the intensity of the <span class="hlt">solar</span> plasmas acceleration process. Correlation studies of these data combined with the magnetic field strength at the <span class="hlt">solar</span> corona level revealed several types of the <span class="hlt">solar</span> <span class="hlt">wind</span> streams differing in the final result, the velocity at large distances from the Sun. Besides of the well-known flows stemming from the polar coronal holes, high-speed streams were observed arising in lateral areas of the streamer structures in contrast to the main body of the streamers, being a known source of the slow <span class="hlt">solar</span> <span class="hlt">wind</span>. The slowest streams arise at areas of mixed magnetic field structure compris- ing both open and closed (loop-like) filed lines. In the white-light corona images this shows extensive areas of bright amorphous luminosity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.nrel.gov/grid/hawaii-integration-studies.html','SCIGOVWS'); return false;" href="https://www.nrel.gov/grid/hawaii-integration-studies.html"><span>Hawaii <span class="hlt">Solar</span> and <span class="hlt">Wind</span> Integration Studies | Grid Modernization | NREL</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p><span class="hlt">Solar</span> Integration <em>Study</em> and Oahu <span class="hlt">Wind</span> Integration and Transmission <em>Study</em> investigated the effects of high penetrations of renewables on island grids. Hawaii <span class="hlt">Solar</span> Integration <em>Study</em> The Hawaii <span class="hlt">Solar</span> Integration <em>Study</em> was a detailed technical examination of the effects of high penetrations of <span class="hlt">solar</span> and <span class="hlt">wind</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090006630&hterms=figueroa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dfigueroa','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090006630&hterms=figueroa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dfigueroa"><span>Variations of Strahl Properties with Fast and Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Figueroa-Vinas, Adolfo; Goldstein, Melvyn L.; Gurgiolo, Chris</p> <p>2008-01-01</p> <p>The interplanetary <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> during high and slow speed <span class="hlt">solar</span> <span class="hlt">wind</span>. The moment density and fluid velocity have been computed by a semi-numerical integration method. The variations of <span class="hlt">solar</span> <span class="hlt">wind</span> density and drift velocity with the general build <span class="hlt">solar</span> <span class="hlt">wind</span> speed could provide some insight into the source, origin, and evolution of the strahl.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910047213&hterms=radiation+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dradiation%2BSolar','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910047213&hterms=radiation+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dradiation%2BSolar"><span>Erosion of carbon/carbon by <span class="hlt">solar</span> <span class="hlt">wind</span> charged particle radiation during a <span class="hlt">solar</span> probe mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sokolowski, Witold; O'Donnell, Tim; Millard, Jerry</p> <p>1991-01-01</p> <p>The possible erosion of a carbon/carbon thermal shield by <span class="hlt">solar</span> <span class="hlt">wind</span>-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 <span class="hlt">solar</span> radii. Erosion rates are analytically estimated under several conservative assumptions for a normal quiet and worst case <span class="hlt">solar</span> <span class="hlt">wind</span> storm conditions. Mass loss analyses and comparison studies surprisingly indicate that the predicted erosion rate by <span class="hlt">solar</span> <span class="hlt">wind</span> could be greater than by nominal free sublimation during <span class="hlt">solar</span> <span class="hlt">wind</span> storm conditions at four <span class="hlt">solar</span> radii. The predicted overall mass loss of a carbon/carbon shield material during the critical four <span class="hlt">solar</span> radii flyby can still meet the mass loss mission requirement of less than 0.0025 g/sec.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.4581C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.4581C"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> ion density variations that preceded the M6+ earthquakes occurring on a global scale between 3 and 15 September 2013</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino</p> <p>2015-04-01</p> <p>Between 3 and 15 September 2013 on Earth were recorded nine M6+ earthquakes: Canada M6,1 earthquake occurred on 3 September at 20:19 UTC; Japan M6,5 earthquake occurred on 4 September at 00:18 UTC; Canada M6,0 earthquake occurred on 4 September at 00:23 UTC; Alaska M6,5 earthquake occurred on 4 September at 02:32 UTC; Alaska M6,0 earthquake occurred on 4 September at 06:27 UTC; Northern Mid-Atlantic Ridge M6,0 earthquake occurred on 5 September at 04:01 UTC; Guatemala M6,4 earthquake occurred on 7 September at 00:13 UTC; Central East Pacific Rise M6,1 earthquake occurred on 11 September at 12:44 UTC; Alaska M6,1 earthquake occurred on 15 September at 16:21 UTC. The authors analyzed the modulation of <span class="hlt">solar</span> <span class="hlt">wind</span> ion density during the period from 1 to 18 September 2013 to determine whether the nine earthquakes were preceded by a variations of the <span class="hlt">solar</span> <span class="hlt">wind</span> ion density and for testing a method to be applied in the future also for the prediction of tsunami. The data on ion density used to realize the correlation study are represented by: <span class="hlt">solar</span> <span class="hlt">wind</span> ion density variation detected by <span class="hlt">ACE</span> (Advanced Composition Explorer) Satellite, in orbit near the L1 Lagrange point, at 1.5 million of km from Earth, in direction of the Sun. The instrument used to perform the measurement of the <span class="hlt">solar</span> <span class="hlt">wind</span> ion density is the Electron, Proton, and Alpha Monitor (EPAM) instrument, equipped on the <span class="hlt">ACE</span> Satellite. To conduct the study, the authors have taken in consideration the variation of the <span class="hlt">solar</span> <span class="hlt">wind</span> protons density that have these characteristics: differential proton flux 1060-1900 keV (p/cm^2-sec-ster-MeV); differential proton flux 761-1220 keV (p/cm^2-sec-ster-MeV); differential proton flux 310-580 keV (p/cm^2-sec-ster-MeV) and differential proton flux 115-195 keV (p/cm^2-sec-ster-MeV). This data set has been marked with the times (time markers) of M6+ earthquakes occurred on a global scale (the data on M6+ seismic activity are provided in real time by USGS, INGV and the CSEM) between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.nrel.gov/news/press/1997/56stocksh.html','SCIGOVWS'); return false;" href="https://www.nrel.gov/news/press/1997/56stocksh.html"><span>Free Consumer Workshops On <span class="hlt">Solar</span> & <span class="hlt">Wind</span> Power</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p><em>Free</em> Consumer Workshops On <span class="hlt">Solar</span> & <span class="hlt">Wind</span> Power For Farm & Ranch At National Western Stock three <em>free</em> consumer workshops on <span class="hlt">solar</span> and <span class="hlt">wind</span> power for the farm and ranch at the 1998 National information booth in the Stock Show's Hall of Education. <em>Free</em> literature on renewable energy is available at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003114&hterms=Wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DWind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003114&hterms=Wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DWind"><span>Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Observations and Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abbo, L.; Ofman, L.; Antiochos, S. K.; Hansteen, V. H.; Harra, L.; Ko, Y.-K.; Lapenta, G.; Li, B.; Riley, P.; Strachan, L.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170003114'); toggleEditAbsImage('author_20170003114_show'); toggleEditAbsImage('author_20170003114_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170003114_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170003114_hide"></p> <p>2016-01-01</p> <p>While it is certain that the fast <span class="hlt">solar</span> <span class="hlt">wind</span> originates from coronal holes, where and how the slow <span class="hlt">solar</span> <span class="hlt">wind</span> (SSW) is formed remains an outstanding question in <span class="hlt">solar</span> physics even in the post-SOHO era. The quest for the SSW origin forms a major objective for the planned future missions such as the <span class="hlt">Solar</span> Orbiter and <span class="hlt">Solar</span> Probe Plus. Nonetheless, results from spacecraft data, combined with theoretical modeling, have helped to investigate many aspects of the SSW. Fundamental physical properties of the coronal plasma have been derived from spectroscopic and imaging remote-sensing data and in situ data, and these results have provided crucial insights for a deeper understanding of the origin and acceleration of the SSW. Advanced models of the SSW in coronal streamers and other structures have been developed using 3D MHD and multi-fluid equations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.2141R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.2141R"><span>Intermittency of <span class="hlt">solar</span> <span class="hlt">wind</span> on scale 0.01-16 Hz.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riazantseva, Maria; Zastenker, Georgy; Chernyshov, Alexander; Petrosyan, Arakel</p> <p></p> <p>Magnetosphere of the Earth is formed in the process of <span class="hlt">solar</span> <span class="hlt">wind</span> flow around earth's magnetic field. <span class="hlt">Solar</span> <span class="hlt">wind</span> is a flow of turbulent plasma that displays a multifractal structure and an intermittent character. That is why the study of the characteristics of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence is very important part of the solution of the problem of the energy transport from the <span class="hlt">solar</span> <span class="hlt">wind</span> to magnetosphere. A large degree of intermittency is observed in the <span class="hlt">solar</span> <span class="hlt">wind</span> ion flux and magnetic field time rows. We investigated the intermittency of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> regions in which SCIF is observed more frequently. We use nearly incompressible model of the <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence for obtained data interpretation. The regime when density fluctuations are passive scalar in a hydrodynamic field of velocity is realized in turbulent <span class="hlt">solar</span> <span class="hlt">wind</span> flows according to this model. This hypothesis can be verified</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28139769','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28139769"><span>Global <span class="hlt">solar</span> <span class="hlt">wind</span> variations over the last four centuries.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Owens, M J; Lockwood, M; Riley, P</p> <p>2017-01-31</p> <p>The most recent "grand minimum" of <span class="hlt">solar</span> activity, the Maunder minimum (MM, 1650-1710), is of great interest both for understanding the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed, and up to a factor 4 increase in <span class="hlt">solar</span> <span class="hlt">wind</span> Mach number. Thus <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> irradiance estimates during grand minima.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5282500','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5282500"><span>Global <span class="hlt">solar</span> <span class="hlt">wind</span> variations over the last four centuries</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Owens, M. J.; Lockwood, M.; Riley, P.</p> <p>2017-01-01</p> <p>The most recent “grand minimum” of <span class="hlt">solar</span> activity, the Maunder minimum (MM, 1650–1710), is of great interest both for understanding the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> corona to calibrate heliospheric reconstructions based solely on sunspot observations. Using these empirical relations, we produce the first quantitative estimate of global <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed, and up to a factor 4 increase in <span class="hlt">solar</span> <span class="hlt">wind</span> Mach number. Thus <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> irradiance estimates during grand minima. PMID:28139769</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH32A..01K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH32A..01K"><span>Understanding non-equilibrium collisional and expansion effects in the <span class="hlt">solar</span> <span class="hlt">wind</span> with Parker <span class="hlt">Solar</span> Probe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korreck, K. E.; Klein, K. G.; Maruca, B.; Alterman, B. L.</p> <p>2017-12-01</p> <p>The evolution of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> need to be separated in order to understand and distinguish the dominant mechanism for heating and acceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span>. With the upcoming launch in 2018 of Parker <span class="hlt">Solar</span> Probe and the launch of <span class="hlt">Solar</span> Orbiter after, addressing the local and global phenomena will be enabled with in situ measurements. Parker <span class="hlt">Solar</span> Probe will go closer to the Sun than any previous mission enabling the ability to examine the <span class="hlt">solar</span> <span class="hlt">wind</span> at an early expansion age. This work examines the predictions for what will be seen inside of the 0.25 AU (54 <span class="hlt">solar</span> radii) where Parker <span class="hlt">Solar</span> 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 <span class="hlt">Solar</span> Probe measurements will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720003183','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720003183"><span>Dynamics of the <span class="hlt">solar</span> <span class="hlt">wind</span> and its interaction with bodies in the <span class="hlt">solar</span> system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spreiter, J. R.</p> <p>1971-01-01</p> <p>A discussion of the <span class="hlt">solar</span> <span class="hlt">wind</span> and its interaction with bodies of the <span class="hlt">solar</span> system is presented. An overall unified account of the role of shock waves in the heating of the <span class="hlt">solar</span> corona, the transmission of <span class="hlt">solar</span> disturbances to the <span class="hlt">solar</span> system, the flow fields of planets and natural satellites, and biological effects are provided. An analysis of magnetometer data from Explorer 33 and Vela 3A satellites to identify characteristics of <span class="hlt">solar</span> <span class="hlt">wind</span> shock waves is included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.2222F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.2222F"><span>Magnetosheath for almost-aligned <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field and flow vectors: Windobservations across the dawnside magnetosheath at X = -12 Re</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farrugia, Charles</p> <p></p> <p>While there are many approximations describing the flow of the <span class="hlt">solar</span> <span class="hlt">wind</span> past the mag-netosphere in the magnetosheath, the case of perfectly aligned (parallel or anti-parallel) in-terplanetary magnetic field (IMF) and <span class="hlt">solar</span> <span class="hlt">wind</span> flow vectors can be treated exactly in an magnetohydrodynamic (MHD) approach (Spreiter and Rizzi, 1974). In this work we examine a case of nearly-opposed (to within 15 deg) interplanetary field and flow vectors, which occurred on October 24-25, 2001 during passage of the last interplanetary coronal mass ejection in an ejecta merger. Interplanetary data are from the <span class="hlt">ACE</span> spacecraft. Simultaneously <span class="hlt">Wind</span> was crossing the near-Earth (X -13 Re) geomagnetic tail and subsequently made a 5-hour-long magnetosheath crossing close to the ecliptic plane (Z = -0.7 Re). Geomagnetic activity was returning steadily to quiet, "ground" conditions. We first compare the predictions of the Spre-iter and Rizzi theory with the <span class="hlt">Wind</span> magnetosheath observations and find fair agreement, in particular as regards the proportionality of the magnetic field strength and the product of the plasma density and bulk speed. We then carry out a small-perturbation analysis of the Spreiter and Rizzi solution to account for the small IMF components perpendicular to the flow vector. The resulting expression is compared to the time series of the observations and satisfactory agreement is obtained. We also present and discuss observations in the dawnside boundary layer of pulsed, high-speed (v 600 km/s) flows exceeding the <span class="hlt">solar</span> <span class="hlt">wind</span> flow speeds. We examine various generating mechanisms and suggest that the most likely causeis a wave of frequency 3.2 mHz excited at the inner edge of the boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950053630&hterms=foreshock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dforeshock','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950053630&hterms=foreshock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dforeshock"><span>A study of the <span class="hlt">solar</span> <span class="hlt">wind</span> deceleration in the Earth's foreshock region</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, T.-L.; Schwingenschuh, K.; Russell, C. T.</p> <p>1995-01-01</p> <p>Previous observations have shown that the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> may decrease tens of km/s in the foreshock region. The <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure exerted on the magnetopause may vary due to the fluctuation of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and density in the foreshock region. In this study, we examine this <span class="hlt">solar</span> <span class="hlt">wind</span> deceleration and determine how the <span class="hlt">solar</span> <span class="hlt">wind</span> deceleration varies in the foreshock region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..899A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..899A"><span>Modelling Magnetodisc Response to <span class="hlt">Solar</span> <span class="hlt">Wind</span> Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Achilleos, N.; Guio, P.; Arridge, C. S.</p> <p>2017-09-01</p> <p>The Sun's influence is felt by planets in the <span class="hlt">solar</span> system in many different ways. In this work, we use theoretical models of the magnetic fields of the Gas Giants (Jupiter and Saturn) to predict how they would change in response to compressions and expansions in the flow of charged particles ('<span class="hlt">solar</span> <span class="hlt">wind</span>') which continually emanates from the Sun. This in an example of 'Space Weather' - the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetized planets, such as Jupiter, Saturn and even the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSH51E2624S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSH51E2624S"><span>Charged-Particle Transport in the Data-Driven, Non-Isotropic Turbulent Mangetic Field in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, P.; Jokipii, J. R.; Giacalone, J.</p> <p>2016-12-01</p> <p>Anisotropies in astrophysical turbulence has been proposed and observed for a long time. And recent observations adopting the multi-scale analysis techniques provided a detailed description of the scale-dependent power spectrum of the magnetic field parallel and perpendicular to the scale-dependent magnetic field line at different scales in the <span class="hlt">solar</span> <span class="hlt">wind</span>. In the previous work, we proposed a multi-scale method to synthesize non-isotropic turbulent magnetic field with pre-determined power spectra of the fluctuating magnetic field as a function of scales. We present the effect of test particle transport in the resulting field with a two-scale algorithm. We find that the scale-dependent turbulence anisotropy has a significant difference in the effect on charged par- ticle transport from what the isotropy or the global anisotropy has. It is important to apply this field synthesis method to the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field based on spacecraft data. However, this relies on how we extract the power spectra of the turbulent magnetic field across different scales. In this study, we propose here a power spectrum synthesis method based on Fourier analysis to extract the large and small scale power spectrum from a single spacecraft observation with a long enough period and a high sampling frequency. We apply the method to the <span class="hlt">solar</span> <span class="hlt">wind</span> measurement by the magnetometer onboard the <span class="hlt">ACE</span> spacecraft and regenerate the large scale isotropic 2D spectrum and the small scale anisotropic 2D spectrum. We run test particle simulations in the magnetid field generated in this way to estimate the transport coefficients and to compare with the isotropic turbulence model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070021568&hterms=solar+energy+advantage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Benergy%2Badvantage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070021568&hterms=solar+energy+advantage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Benergy%2Badvantage"><span>Measurement of Damage Profiles from <span class="hlt">Solar</span> <span class="hlt">Wind</span> Implantation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McNamara, K. M.; Synowicki, R. A.; Tiwald, T. E.</p> <p>2007-01-01</p> <p>NASA's Genesis Mission launched from Cape Canaveral in August of 2001 with the goal of collecting <span class="hlt">solar</span> <span class="hlt">wind</span> in ultra-pure materials. The samples were returned to Earth more than three years later for subsequent analysis. Although the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> samples (continuous exposure), the Genesis mission actually returned silicon exposed to four different <span class="hlt">solar</span> <span class="hlt">wind</span> regimes: bulk, high speed, low speed, and coronal mass ejections. Each of these <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> regime. Here, we examine flight Si from the bulk <span class="hlt">solar</span> <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070009876','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070009876"><span>Badhwar-O'Neil 2007 Galactic Cosmic Ray (GCR) Model Using Advanced Composition Explorer (<span class="hlt">ACE</span>) Measurements for <span class="hlt">Solar</span> Cycle 23</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>ONeill, P. M.</p> <p>2007-01-01</p> <p>Advanced Composition Explorer (<span class="hlt">ACE</span>) satellite measurements of the galactic cosmic ray flux and correlation with the Climax Neutron Monitor count over <span class="hlt">Solar</span> Cycle 23 are used to update the Badhwar O'Neill Galactic Cosmic Ray (GCR) model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22127011-bidirectional-fluxes-nearly-relativistic-electrons-during-onset-solar-energetic-particle-events','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22127011-bidirectional-fluxes-nearly-relativistic-electrons-during-onset-solar-energetic-particle-events"><span>BIDIRECTIONAL FLUXES OF NEARLY RELATIVISTIC ELECTRONS DURING THE ONSET OF <span class="hlt">SOLAR</span> ENERGETIC PARTICLE EVENTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Sun, L. P.; Li, C., E-mail: pmo_sunlp@msn.com</p> <p>2013-03-10</p> <p>We report intensity and anisotropy measurements of energetic electrons in the energy range of {approx}27-{approx}500 keV as observed with the <span class="hlt">Wind</span> and Advanced Composition Explorer (<span class="hlt">ACE</span>) spacecraft in 2000 June for several <span class="hlt">solar</span> energetic particle (SEP) events. The <span class="hlt">solar</span> sources of the SEP events are inferred from observations from the <span class="hlt">Solar</span> and Heliospheric Observatory spacecraft. All of the events originate from the western limb active regions (ARs), which are well connected by interplanetary magnetic field (IMF) lines linking the Sun to near-Earth space. The observations on board <span class="hlt">Wind</span> show bimodal pitch angle distributions (PADs), whereas <span class="hlt">ACE</span> shows PADs with onemore » peak, as is usually observed for impulsive injection of electrons at the Sun. During the time of observations, <span class="hlt">Wind</span> was located, upstream of the Earth's bow shock in the dawn-noon sector, at distances of {approx}40-{approx}80 R{sub E} from the Earth, and we infer that it was magnetically connected to the quasi-parallel bow shock. Meanwhile, <span class="hlt">ACE</span>, orbiting the Sun-Earth libration point L1, was not connected to the bow shock. The electron intensity-time profiles and the energy spectra show that the backstreaming electrons observed at <span class="hlt">Wind</span> are not of magnetospheric origin. The observations suggest rather that the bidirectional electron fluxes are due to reflection or scattering by an obstacle located at a distance of less than {approx}150 R{sub E} in the anti-sunward direction, which is compatible with the obstacle being the Earth's bow shock or magnetosheath.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SoPh..292...90R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SoPh..292...90R"><span>Origin and Ion Charge State Evolution of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Transients during 4 - 7 August 2011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodkin, D.; Goryaev, F.; Pagano, P.; Gibb, G.; Slemzin, V.; Shugay, Y.; Veselovsky, I.; Mackay, D. H.</p> <p>2017-07-01</p> <p>We present a study of the complex event consisting of several <span class="hlt">solar</span> <span class="hlt">wind</span> transients detected by the Advanced Composition Explorer (<span class="hlt">ACE</span>) on 4 - 7 August 2011, which caused a geomagnetic storm with Dst=-110 nT. The supposed coronal sources, three flares and coronal mass ejections (CMEs), occurred on 2 - 4 August 2011 in active region (AR) 11261. To investigate the <span class="hlt">solar</span> origin and formation of these transients, we study the kinematic and thermodynamic properties of the expanding coronal structures using the <span class="hlt">Solar</span> Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) EUV images and differential emission measure (DEM) diagnostics. The Helioseismic and Magnetic Imager (HMI) magnetic field maps were used as the input data for the 3D magnetohydrodynamic (MHD) model to describe the flux rope ejection (Pagano, Mackay, and Poedts, 2013b). We characterize the early phase of the flux rope ejection in the corona, where the usual three-component CME structure formed. The flux rope was ejected with a speed of about 200 km s^{-1} to the height of 0.25 R_{⊙}. The kinematics of the modeled CME front agrees well with the <span class="hlt">Solar</span> Terrestrial Relations Observatory (STEREO) EUV measurements. Using the results of the plasma diagnostics and MHD modeling, we calculate the ion charge ratios of carbon and oxygen as well as the mean charge state of iron ions of the 2 August 2011 CME, taking into account the processes of heating, cooling, expansion, ionization, and recombination of the moving plasma in the corona up to the frozen-in region. We estimate a probable heating rate of the CME plasma in the low corona by matching the calculated ion composition parameters of the CME with those measured in situ for the <span class="hlt">solar</span> <span class="hlt">wind</span> transients. We also consider the similarities and discrepancies between the results of the MHD simulation and the observations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4508929','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4508929"><span>Ensemble downscaling in coupled <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere modeling for space weather forecasting</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Owens, M J; Horbury, T S; Wicks, R T; McGregor, S L; Savani, N P; Xiong, M</p> <p>2014-01-01</p> <p>Advanced forecasting of space weather requires simulation of the whole Sun-to-Earth system, which necessitates driving magnetospheric models with the outputs from <span class="hlt">solar</span> <span class="hlt">wind</span> models. This presents a fundamental difficulty, as the magnetosphere is sensitive to both large-scale <span class="hlt">solar</span> <span class="hlt">wind</span> structures, which can be captured by <span class="hlt">solar</span> <span class="hlt">wind</span> models, and small-scale <span class="hlt">solar</span> <span class="hlt">wind</span> “noise,” which is far below typical <span class="hlt">solar</span> <span class="hlt">wind</span> model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical “downscaling” of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> model output by smoothing <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> downscaling scheme. Key Points <span class="hlt">Solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> fluctuations PMID:26213518</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26213518','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26213518"><span>Ensemble downscaling in coupled <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere modeling for space weather forecasting.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Owens, M J; Horbury, T S; Wicks, R T; McGregor, S L; Savani, N P; Xiong, M</p> <p>2014-06-01</p> <p>Advanced forecasting of space weather requires simulation of the whole Sun-to-Earth system, which necessitates driving magnetospheric models with the outputs from <span class="hlt">solar</span> <span class="hlt">wind</span> models. This presents a fundamental difficulty, as the magnetosphere is sensitive to both large-scale <span class="hlt">solar</span> <span class="hlt">wind</span> structures, which can be captured by <span class="hlt">solar</span> <span class="hlt">wind</span> models, and small-scale <span class="hlt">solar</span> <span class="hlt">wind</span> "noise," which is far below typical <span class="hlt">solar</span> <span class="hlt">wind</span> model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical "downscaling" of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> model output by smoothing <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> downscaling scheme. <span class="hlt">Solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH43A..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH43A..03W"><span>Turbulent Heating and Wave Pressure in <span class="hlt">Solar</span> <span class="hlt">Wind</span> Acceleration Modeling: New Insights to Empirical Forecasting of the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woolsey, L. N.; Cranmer, S. R.</p> <p>2013-12-01</p> <p>The study of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">wind</span> speed. This code, therefore, can make predictions of the <span class="hlt">wind</span> 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 <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.963K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.963K"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma Flows and Space Weather Aspects Recent <span class="hlt">Solar</span> Cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaushik, Sonia; Kaushik, Subhash Chandra</p> <p>2016-07-01</p> <p><span class="hlt">Solar</span> transients are responsible for initiating short - term and long - term variations in earth's magnetosphere. These variations are termed as geomagnetic disturbances, and driven by the interaction of <span class="hlt">solar</span> <span class="hlt">wind</span> features with the geo-magnetosphere. The strength of this modulation process depends upon the magnitude and orientation of the Interplanetary Magnetic Field and <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. These interplanetary transients are large scale structures containing plasma and magnetic field expelled from the transient active regions of <span class="hlt">solar</span> atmosphere. As they come to interplanetary medium the interplanetary magnetic field drape around them. This field line draping was thought as possible cause of the characteristic eastward deflection and giving rise to geomagnetic activities as well as a prime factor in producing the modulation effects in the near Earth environment. The <span class="hlt">Solar</span> cycle 23 has exhibited the unique extended minima and peculiar effects in the geomagnetosphere. Selecting such transients, occurred during this interval, an attempt has been made to determine quantitative relationships of these transients with <span class="hlt">solar</span>/ interplanetary and Geophysical Parameters. In this work we used hourly values of IMF data obtained from the NSSD Center. The analysis mainly based on looking into the effects of these transients on earth's magnetic field. The high-resolution data IMF Bz and <span class="hlt">solar</span> <span class="hlt">wind</span> data obtained from WDC-A, through its omniweb, available during the selected period. Dst and Ap obtained from WDC-Kyoto are taken as indicator of geomagnetic activities. It is found that Dst index, <span class="hlt">solar</span> <span class="hlt">wind</span> velocity, proton temperature and the Bz component of magnetic field have higher values and increase just before the occurrence of these events. Larger and varying magnetic field mainly responsible for producing the short-term changes in geomagnetic intensity are observed during these events associated with coronal holes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914825O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914825O"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> parameteres and disturbances in STEREO view</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Opitz, Andrea</p> <p>2017-04-01</p> <p>The twin STEREO spacecraft provided two vantage point <span class="hlt">solar</span> <span class="hlt">wind</span> observations between 2007 and 2014. Instrumentation of the STEREO A and B spacecraft is very nearly identical, hence their measurements are easily comparable. These measurements are visualised and treated with different methods in order to obtain a global view of the in-ecliptic background <span class="hlt">solar</span> <span class="hlt">wind</span> and the disturbances such as CIRs and CMEs. Comparison of the two datasets and exclusion of spatial effects provides information on the in-ecliptic <span class="hlt">solar</span> <span class="hlt">wind</span> structure in the inner heliosphere. These methods and results will be revised in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021278&hterms=atom+composition&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Datom%2Bcomposition','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021278&hterms=atom+composition&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Datom%2Bcomposition"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> ion composition and charge states</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>vonSteiger, R.</p> <p>1995-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span>, a highly tenuous plasma streaming from the Sun into interplanetary space at supersonic speed, is roughly composed of 95% hydrogen and 5% helium by number. All other, heavy elements contribute less than 0.1% by number and thus are truly test particles Nevertheless, these particles provide valuable information not present in the main components. We first discuss the importance of the heavy ions as tracers for processes in the <span class="hlt">solar</span> atmosphere. Specifically, their relative abundances are found to be different in the <span class="hlt">solar</span> <span class="hlt">wind</span> as compared to the photosphere. This fractionation, which is best organized as a function of the first ionization time (FIT) of the elements under <span class="hlt">solar</span> surface conditions, provides information on the structure of the chromosphere. where it is imparted on the partially ionized material by an atom-ion separation mechanism. Moreover, the charge states of the heavy ions can be used to infer the coronal temperature, since they are frozen-in near the altitude where the expansion time scale overcomes the ionization/recombination time scales. Next, we review the published values of ion abundances in the <span class="hlt">solar</span> <span class="hlt">wind</span>, concentrating on the recent results of the SWICS instrument on Ulysses. About 8 elements and more than 20 charge states can be routinely analyzed by this sensor. There is clear evidence that both the composition and the charge state distribution is significantly different in the fast <span class="hlt">solar</span> <span class="hlt">wind</span> from the south polar coronal hole, traversed by Ulysses in 1993/94, as compared to the <span class="hlt">solar</span> <span class="hlt">wind</span> normally encountered near the ecliptic plane. The fractionation between low- and high-FIT elements is reduced, and the charge states indicate a lower, more uniform coronal temperature in the hole. Finally, we discuss these results in the framework of existing theoretical models of the chromosphere and corona, attempting to identify differences between the low- and high-latitude regions of the <span class="hlt">solar</span> atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770059881&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D80%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770059881&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D80%26Ntt%3Dlazarus"><span>A comparison of <span class="hlt">solar</span> <span class="hlt">wind</span> streams and coronal structure near <span class="hlt">solar</span> minimum</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nolte, J. T.; Davis, J. M.; Gerassimenko, M.; Lazarus, A. J.; Sullivan, J. D.</p> <p>1977-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> data from the MIT detectors on the IMP 7 and 8 satellites and the SOLRAD 11B satellite for the <span class="hlt">solar</span>-minimum period September-December, 1976, were compared with X-ray images of the <span class="hlt">solar</span> corona taken by rocket-borne telescopes on September 16 and November 17, 1976. There was no compelling evidence that a coronal hole was the source of any high speed stream. Thus it is possible that either coronal holes were not the sources of all recurrent high-speed <span class="hlt">solar</span> <span class="hlt">wind</span> streams during the declining phase of the <span class="hlt">solar</span> cycle, as might be inferred from the Skylab period, or there was a change in the appearance of some magnetic field regions near the time of <span class="hlt">solar</span> minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080030140&hterms=puzzle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpuzzle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080030140&hterms=puzzle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpuzzle"><span>Magnetofluid Turbulence in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvyn L.</p> <p>2008-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> shows striking characteristics that suggest that it is a turbulent magnetofluid, but the picture is not altogether simple. From the earliest observations, a strong correlation between magnetic fluctuations and plasma velocity fluctuations was noted. The high corrections suggest that the fluctuations are Alfven waves. In addition, the power spectrum of the magnetic fluctuation showed evidence of an inertial range that resembled that seen in fully-developed fluid turbulence. Alfven waves, however, are exact solutions of the equations of incompressible magnetohydrodynamics. Thus, there was a puzzle: how can a magnetofluid consisting of Alfven waves be turbulent? The answer lay in the role of velocity shears in the <span class="hlt">solar</span> <span class="hlt">wind</span> that could drive turbulent evolution. Puzzles remain: for example, the power spectrum of the velocity fluctuations is less steep than the slope of the magnetic fluctuations, nor do we understand even now why the <span class="hlt">solar</span> <span class="hlt">wind</span> appears to be nearly incompressible with a -5/3 power-spectral index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..200..495M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..200..495M"><span>The MAVEN <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electron Analyzer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mitchell, D. L.; Mazelle, C.; Sauvaud, J.-A.; Thocaven, J.-J.; Rouzaud, J.; Fedorov, A.; Rouger, P.; Toublanc, D.; Taylor, E.; Gordon, D.; Robinson, M.; Heavner, S.; Turin, P.; Diaz-Aguado, M.; Curtis, D. W.; Lin, R. P.; Jakosky, B. M.</p> <p>2016-04-01</p> <p>The MAVEN <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electron Analyzer (SWEA) is a symmetric hemispheric electrostatic analyzer with deflectors that is designed to measure the energy and angular distributions of 3-4600-eV electrons in the Mars environment. This energy range is important for impact ionization of planetary atmospheric species, and encompasses the <span class="hlt">solar</span> <span class="hlt">wind</span> core and halo populations, shock-energized electrons, auroral electrons, and ionospheric primary photoelectrons. The instrument is mounted at the end of a 1.5-meter boom to provide a clear field of view that spans nearly 80 % of the sky with ˜20° resolution. With an energy resolution of 17 % (Δ E/E), SWEA readily distinguishes electrons of <span class="hlt">solar</span> <span class="hlt">wind</span> and ionospheric origin. Combined with a 2-second measurement cadence and on-board real-time pitch angle mapping, SWEA determines magnetic topology with high (˜8-km) spatial resolution, so that local measurements of the plasma and magnetic field can be placed into global context.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSA42A..05C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSA42A..05C"><span>Thermosphere-Ionosphere Fe/Fe+ (TIFe) Layers and Their Coupling with Geomagnetic Storms and <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, X.; Xu, Z.; Zhao, J.; Yu, Z.; Knipp, D. J.; Kilcommons, L. M.; Chen, C.; Fong, W.; Barry, I. F.; Hartinger, M.</p> <p>2016-12-01</p> <p>The discovery of thermospheric neutral Fe layers by lidar observations in Antarctica has opened a new door to explore the space-atmosphere interactions with ground-based instruments, especially in the least understood but crucially important altitude range of 100-200 km. These neutral metal layers provide excellent tracers for modern resonance lidars to measure the neutral <span class="hlt">wind</span> and temperature directly, complementing the radar measurements of the ionosphere and the magnetometer measurements of the geomagnetic field. Even more exciting, the neutral metal layers in the thermosphere provide a natural laboratory to test our fundamental understandings of the atmosphere-ionosphere-magnetosphere (AIM) coupling and processes. The stunning Fe layer event on 28 May 2011 with clear gravity wave signatures has been simulated successfully with the University of Colorado Thermosphere-Ionosphere Fe/Fe+ (TIFe) model, confirming the theoretical hypothesis that such thermospheric Fe layers are produced through the neutralization of converged Fe+layers. Over 5.5 years of lidar observations at McMurdo have revealed many more cases with variety of patterns - besides the `gravity wave' patterns, there are `diffusive' patterns with both upward and downward phase progressions of Fe layers, and `superposition' patterns with both gravity wave signature and diffusive background. Surprisingly, these Fe layer events exhibit close correlations with geomagnetic storms. They also correspond to remarkable activity of extreme <span class="hlt">solar</span> <span class="hlt">wind</span> events, e.g., high-speed stream (HSS) and coronal mass ejection (CME), etc. This paper conducts a systematic investigation of the coupling among TIFe layers, geomagnetic storms, <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF via combining ground-based lidar, magnetometer, and SuperDARN data with DMSP, <span class="hlt">ACE</span> and <span class="hlt">WIND</span> satellite data along with the TIFe model simulations. We aim to quantitatively determine the relationship between TIFe and magnetic storms, and explore the mechanisms responsible for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840024844','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840024844"><span><span class="hlt">Wind</span> loading on <span class="hlt">solar</span> concentrators: Some general considerations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roschke, E. J.</p> <p>1984-01-01</p> <p>A survey was completed to examine the problems and complications arising from <span class="hlt">wind</span> loading on <span class="hlt">solar</span> concentrators. <span class="hlt">Wind</span> loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of <span class="hlt">solar</span> collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. <span class="hlt">Wind</span> characteristics are discussed from a general point of view. Current methods for determining design <span class="hlt">wind</span> speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. <span class="hlt">Wind</span> tunnel testing is discussed, and environmental <span class="hlt">wind</span> tunnels are reviewed. Recent results on heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930049573&hterms=solar+two&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsolar%2Btwo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930049573&hterms=solar+two&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsolar%2Btwo"><span>A two-fluid model of the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandbaek, O.; Leer, E.; Holzer, T. E.</p> <p>1992-01-01</p> <p>A method is presented for the integration of the two-fluid <span class="hlt">solar-wind</span> equations which is applicable to a wide variety of coronal base densities and temperatures. The method involves proton heat conduction, and may be applied to coronal base conditions for which subsonic-supersonic <span class="hlt">solar</span> <span class="hlt">wind</span> solutions exist.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMSH33A0369A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMSH33A0369A"><span>Genesis <span class="hlt">Solar</span> <span class="hlt">Wind</span> Array Collector Fragments Post-Recovery Status</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allton, J. H.</p> <p>2005-12-01</p> <p>The Genesis <span class="hlt">solar</span> <span class="hlt">wind</span> sample return mission spacecraft was launched with 271 whole and 30 half hexagonally-shaped collectors. At 65 cm2 per hexagon, the total collection area was 18,600 cm2. These 301 collectors were comprised of 9 materials mounted on 5 arrays, each of which was exposed to a specific regime of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Thoughtfully, collectors exposed to a specific regime were made of a unique thickness: bulk <span class="hlt">solar</span> <span class="hlt">wind</span> (700 μm thick), transient <span class="hlt">solar</span> <span class="hlt">wind</span> associated with coronal mass ejection (650 μm), high speed <span class="hlt">solar</span> <span class="hlt">wind</span> from coronal holes (600 μm), and interstream low-speed <span class="hlt">solar</span> <span class="hlt">wind</span> (550 μm). Thus, it is easy to distinguish the <span class="hlt">solar</span> <span class="hlt">wind</span> regime sampled by measuring the fragment thickness. Nearly 10,000 fragments have been enumerated, constituting about 20% of the total area. The sapphire-based hexagons survived better than the silicon hexagons as seen in the percent pre-flight whole collectors compared to the percent of recovered fragments in 10 to 25 mm size range. Silicon-based collectors accounted for 57% of the hexagons flown but 18% of the recovered fragments. However, a) gold coating on sapphire accounted for 12% flown and 27% of the recovered; b) aluminum coating on sapphire for 9% flown and 25% of the recovered; c) silicon coating on sapphire for 7% flown and 18% of the recovered; and d) sapphire for 7% flown and 10% of the recovered. Due to the design of the array frames, many of the recovered fragments were trapped in baffles very near their original location and were relatively protected from outside debris. Collector fragments are coated with particulate debris, and there is evidence that a thin molecular film was deposited on collector surfaces during flight. Therefore, in addition to allocations distributed for <span class="hlt">solar</span> <span class="hlt">wind</span> science analysis, poorer quality samples have been used in specimen cleaning tests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Solar+AND+system&id=EJ876099','ERIC'); return false;" href="https://eric.ed.gov/?q=Solar+AND+system&id=EJ876099"><span><span class="hlt">Wind</span> in the <span class="hlt">Solar</span> System</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>McIntosh, Gordon</p> <p>2010-01-01</p> <p>As an astronomy instructor I am always looking for commonly experienced Earthly phenomena to help my students and me understand and appreciate similar occurrences elsewhere in the <span class="hlt">solar</span> system. Recently I wrote short "TPT" articles on frost and precipitation. The present article is on <span class="hlt">winds</span> in the <span class="hlt">solar</span> system. A windy day or storm might…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1000801-possible-improvements-ace-diversity-interchange-methodology','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1000801-possible-improvements-ace-diversity-interchange-methodology"><span>Possible Improvements of the <span class="hlt">ACE</span> Diversity Interchange Methodology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Etingov, Pavel V.; Zhou, Ning; Makarov, Yuri V.</p> <p>2010-07-26</p> <p>North American Electric Reliability Corporation (NERC) grid is operated by about 131 balancing authorities (BA). Within each BA, operators are responsible for managing the unbalance (caused by both load and <span class="hlt">wind</span>). As <span class="hlt">wind</span> penetration levels increase, the challenges of managing power variation increases. Working independently, balancing area with limited regulating/load following generation and high <span class="hlt">wind</span> power penetration faces significant challenges. The benefits of BA cooperation and consolidation increase when there is a significant <span class="hlt">wind</span> energy penetration. To explore the benefits of BA cooperation, this paper investigates <span class="hlt">ACE</span> sharing approach. A technology called <span class="hlt">ACE</span> diversity interchange (ADI) is already in usemore » in the western interconnection. A new methodology extending ADI is proposed in the paper. The proposed advanced ADI overcoming some limitations existing in conventional ADI. Simulations using real statistical data of CAISO and BPA have shown high performance of the proposed advanced ADI methodology.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830025552','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830025552"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> iron abundance variations at <span class="hlt">solar</span> <span class="hlt">wind</span> speeds up to 600 km s sup -1, 1972 to 1976</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mitchell, D. G.; Roelof, E. C.; Bame, S. J.</p> <p>1982-01-01</p> <p>The Fe/H ratios in the peaks of high speed streams (HSS) were analyzed during the decline of <span class="hlt">Solar</span> Cycle 20 and the following minimum (October 1972 to December 1976). The response of the 50 to 200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 was utilized to <span class="hlt">solar</span> <span class="hlt">wind</span> iron ions at high <span class="hlt">solar</span> <span class="hlt">wind</span> speeds (V or = 600 km/sec). Fe measurements with <span class="hlt">solar</span> <span class="hlt">wind</span> H and He parameters were compared from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ration in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 0.00001, abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH12A..03L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH12A..03L"><span>The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Source Cycle: Relationship to Dynamo Behavior</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luhmann, J. G.; Li, Y.; Lee, C. O.; Jian, L. K.; Petrie, G. J. D.; Arge, C. N.</p> <p>2017-12-01</p> <p><span class="hlt">Solar</span> cycle trends of interest include the evolving properties of the <span class="hlt">solar</span> <span class="hlt">wind</span>, the heliospheric medium through which the Sun's plasmas and fields interact with Earth and the planets -including the evolution of CME/ICMEs enroute. <span class="hlt">Solar</span> <span class="hlt">wind</span> sources include the coronal holes-the open field regions that constantly evolve with <span class="hlt">solar</span> magnetic fields as the cycle progresses, and the streamers between them. The recent cycle has been notably important in demonstrating that not all <span class="hlt">solar</span> cycles are alike when it comes to contributions from these sources, including in the case of ecliptic <span class="hlt">solar</span> <span class="hlt">wind</span>. In particular, it has modified our appreciation of the low latitude coronal hole and streamer sources because of their relative prevalence. One way to understand the basic relationship between these source differences and what is happening inside the Sun and on its surface is to use observation-based models like the PFSS model to evaluate the evolution of the coronal field geometry. Although the accuracy of these models is compromised around <span class="hlt">solar</span> maximum by lack of global surface field information and the sometimes non-potential evolution of the field related to more frequent and widespread emergence of active regions, they still approximate the character of the coronal field state. We use these models to compare the inferred recent cycle coronal holes and streamer belt sources of <span class="hlt">solar</span> <span class="hlt">wind</span> with past cycle counterparts. The results illustrate how (still) hemispherically asymmetric weak polar fields maintain a complex mix of low-to-mid latitude <span class="hlt">solar</span> <span class="hlt">wind</span> sources throughout the latest cycle, with a related marked asymmetry in the hemispheric distribution of the ecliptic <span class="hlt">wind</span> sources. This is likely to be repeated until the polar field strength significantly increases relative to the fields at low latitudes, and the latter symmetrize.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016041','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016041"><span>Near-Earth <span class="hlt">Solar</span> <span class="hlt">Wind</span> Flows and Related Geomagnetic Activity During more than Four <span class="hlt">Solar</span> Cycles (1963-2011)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, Ian G.; Cane, Hilary V.</p> <p>2012-01-01</p> <p>In past studies, we classified the near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> into three basic flow types based on inspection of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> observations, thereby encompassing the complete <span class="hlt">solar</span> cycles 20 to 23 and the ascending phase of cycle 24. We discuss the cycle-to-cycle variations in near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> structures and l1e related geomagnetic activity over more than four <span class="hlt">solar</span> cycles, updating some of the results of our earlier studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/971292','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/971292"><span>The genesis <span class="hlt">solar-wind</span> sample return mission</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wiens, Roger C</p> <p>2009-01-01</p> <p>The compositions of the Earth's crust and mantle, and those of the Moon and Mars, are relatively well known both isotopically and elementally. The same is true of our knowledge of the asteroid belt composition, based on meteorite analyses. Remote measurements of Venus, the Jovian atmosphere, and the outer planet moons, have provided some estimates of their compositions. The Sun constitutes a large majority, > 99%, of all the matter in the <span class="hlt">solar</span> system. The elemental composition of the photosphere, the visible 'surface' of the Sun, is constrained by absorption lines produced by particles above the surface. Abundances for manymore » elements are reported to the {+-}10 or 20% accuracy level. However, the abundances of other important elements, such as neon, cannot be determined in this way due to a relative lack of atomic states at low excitation energies. Additionally and most importantly, the isotopic composition of the Sun cannot be determined astronomically except for a few species which form molecules above sunspots, and estimates derived from these sources lack the accuracy desired for comparison with meteoritic and planetary surface samples measured on the Earth. The <span class="hlt">solar</span> <span class="hlt">wind</span> spreads a sample of <span class="hlt">solar</span> particles throughout the heliosphere, though the sample is very rarified: collecting a nanogram of oxygen, the third most abundant element, in a square centimeter cross section at the Earth's distance from the Sun takes five years. Nevertheless, foil collectors exposed to the <span class="hlt">solar</span> <span class="hlt">wind</span> for periods of hours on the surface of the Moon during the Apollo missions were used to determine the helium and neon <span class="hlt">solar-wind</span> compositions sufficiently to show that the Earth's atmospheric neon was significantly evolved relative to the Sun. Spacecraft instruments developed subsequently have provided many insights into the composition of the <span class="hlt">solar</span> <span class="hlt">wind</span>, mostly in terms of elemental composition. These instruments have the advantage of observing a number of parameters</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950037083&hterms=mass+fraction&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmass%2Bfraction','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950037083&hterms=mass+fraction&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmass%2Bfraction"><span>The <span class="hlt">solar</span> cycle variation of coronal mass ejections and the <span class="hlt">solar</span> <span class="hlt">wind</span> mass flux</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Webb, David F.; Howard, Russell A.</p> <p>1994-01-01</p> <p>Coronal mass ejections (CMEs) are an important aspect of coronal physics and a potentially significant contributor to perturbations of the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> sunspot cycle and a comparison of these rates with those of other activity related to CMEs and with the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> activity is better correlated with CME rate than any other; (4) the ratio of the annualized CME to <span class="hlt">solar</span> <span class="hlt">wind</span> mass flux tends to track the <span class="hlt">solar</span> cycle; and (5) near <span class="hlt">solar</span> maximum, CMEs can provide a significant fraction (i.e., approximately equals 15%) of the average mass flux to the near-ecliptic <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720046891&hterms=Magnetic+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMagnetic%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720046891&hterms=Magnetic+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMagnetic%2Benergy"><span>Magnetic energy flow in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Modisette, J. L.</p> <p>1972-01-01</p> <p>Discussion of the effect of rotation (tangential flow) of the <span class="hlt">solar</span> <span class="hlt">wind</span> on the conclusions of Whang (1971) suggesting an increase in the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity due to the conversion of magnetic energy to kinetic energy. It is shown that the effect of the rotation of the sun on the magnetic energy flow results in most of the magnetic energy being transported by magnetic shear stress near the sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22518620-reconstructing-solar-wind-from-its-early-history-current-epoch','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22518620-reconstructing-solar-wind-from-its-early-history-current-epoch"><span>RECONSTRUCTING THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> FROM ITS EARLY HISTORY TO CURRENT EPOCH</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Airapetian, Vladimir S.; Usmanov, Arcadi V., E-mail: vladimir.airapetian@nasa.gov, E-mail: avusmanov@gmail.com</p> <p></p> <p>Stellar <span class="hlt">winds</span> from active <span class="hlt">solar</span>-type stars can play a crucial role in removal of stellar angular momentum and erosion of planetary atmospheres. However, major <span class="hlt">wind</span> properties except for mass-loss rates cannot be directly derived from observations. We employed a three-dimensional magnetohydrodynamic Alfvén wave driven <span class="hlt">solar</span> <span class="hlt">wind</span> model, ALF3D, to reconstruct the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters including the mass-loss rate, terminal velocity, and <span class="hlt">wind</span> temperature at 0.7, 2, and 4.65 Gyr. Our model treats the <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. To study the evolution of the <span class="hlt">solar</span> <span class="hlt">wind</span>, we specified three input model parameters, the plasma density, Alfvén wave amplitude, and the strength of the dipole magnetic field at the <span class="hlt">wind</span> base for each of three <span class="hlt">solar</span> <span class="hlt">wind</span> evolution models that are consistent with observational constrains. Our model results show that the velocity of the paleo <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22518793-turbulence-solar-wind-measured-comet-tail-test-particles','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22518793-turbulence-solar-wind-measured-comet-tail-test-particles"><span>TURBULENCE IN THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> MEASURED WITH COMET TAIL TEST PARTICLES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>DeForest, C. E.; Howard, T. A.; Matthaeus, W. H.</p> <p>2015-10-20</p> <p>By analyzing the motions of test particles observed remotely in the tail of Comet Encke, we demonstrate that the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, followed, on larger scales, by a surprising regime of semiconfinement that we attribute to turbulent eddies in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The entrained kinetic energy of the turbulent motions represents a sufficient energy reservoir to heat the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> is fully mixed by turbulence on scales corresponding to a 1–2 hr crossing time at Earth; and that <span class="hlt">solar</span> <span class="hlt">wind</span> variability on timescales shorter than 1–2 hr is therefore dominated by turbulent processing rather than by direct <span class="hlt">solar</span> effects.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..204..131K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..204..131K"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Electrons Alphas and Protons (SWEAP) Investigation: Design of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Coronal Plasma Instrument Suite for <span class="hlt">Solar</span> Probe Plus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>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</p> <p>2016-12-01</p> <p>The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electrons Alphas and Protons (SWEAP) Investigation on <span class="hlt">Solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and coronal plasma. SWEAP consists of the <span class="hlt">Solar</span> Probe Cup (SPC) and the <span class="hlt">Solar</span> 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 <span class="hlt">Solar</span> Probe Plus. SWEAP measurements, in concert with magnetic and electric fields, energetic particles, and white light contextual imaging will enable discovery and understanding of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration and formation, coronal and <span class="hlt">solar</span> <span class="hlt">wind</span> heating, and particle acceleration in the inner heliosphere of the <span class="hlt">solar</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ApJ...853..142L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ApJ...853..142L"><span>Generation of Kappa Distributions in <span class="hlt">Solar</span> <span class="hlt">Wind</span> at 1 au</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Livadiotis, G.; Desai, M. I.; Wilson, L. B., III</p> <p>2018-02-01</p> <p>We examine the generation of kappa distributions in the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma near 1 au. Several mechanisms are mentioned in the literature, each characterized by a specific relationship between the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and magnetic field properties. Moreover, our findings show that the kappa distributions, and thus, their generating mechanisms, vary significantly with <span class="hlt">solar</span> <span class="hlt">wind</span> features: (i) the kappa index has different dependence on the <span class="hlt">solar</span> <span class="hlt">wind</span> speed for slow and fast modes, i.e., slow <span class="hlt">wind</span> is characterized by a quasi-constant kappa index, κ ≈ 4.3 ± 0.7, while fast <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770051140&hterms=Krieger&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKrieger','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770051140&hterms=Krieger&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DKrieger"><span>High coronal structure of high velocity <span class="hlt">solar</span> <span class="hlt">wind</span> stream sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nolte, J. T.; Krieger, A. S.; Roelof, E. C.; Gold, R. E.</p> <p>1977-01-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> stream sources is strongly suggested by the <span class="hlt">solar</span> <span class="hlt">wind</span> 'dwells' which appear in plots of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> dwells is calculated, showing that the high-velocity stream originates from a significantly lower altitude than the ambient <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790009952&hterms=history+gold&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhistory%2Bgold','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790009952&hterms=history+gold&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhistory%2Bgold"><span>Prediction of <span class="hlt">solar</span> energetic particle event histories using real-time particle and <span class="hlt">solar</span> <span class="hlt">wind</span> measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roelof, E. C.; Gold, R. E.</p> <p>1978-01-01</p> <p>The comparatively well-ordered magnetic structure in the <span class="hlt">solar</span> corona during the decline of <span class="hlt">Solar</span> Cycle 20 revealed a characteristic dependence of <span class="hlt">solar</span> energetic particle injection upon heliographic longitude. When analyzed using <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> velocity (and hence the coronal connection longitude) can severely distort the simple coronal injection profile, the use of real-time <span class="hlt">solar</span> <span class="hlt">wind</span> velocity measurements can be of great aid in predicting the decay of <span class="hlt">solar</span> particle events. Although such exponential injection profiles are commonplace during 1973-1975, they have also been identified earlier in <span class="hlt">Solar</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36..520S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36..520S"><span>Real-time global MHD simulation of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with the earth's magnetosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimazu, H.; Tanaka, T.; Fujita, S.; Nakamura, M.; Obara, T.</p> <p></p> <p>We have developed a real-time global MHD simulation of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with the earth s magnetosphere By adopting the real-time <span class="hlt">solar</span> <span class="hlt">wind</span> parameters including the IMF observed routinely by the <span class="hlt">ACE</span> spacecraft responses of the magnetosphere are calculated with the MHD code We adopted the modified spherical coordinates and the mesh point numbers for this simulation are 56 58 and 40 for the r theta and phi direction respectively The simulation is carried out routinely on the super computer system NEC SX-6 at National Institute of Information and Communications Technology Japan The visualized images of the magnetic field lines around the earth pressure distribution on the meridian plane and the conductivity of the polar ionosphere can be referred to on the Web site http www nict go jp dk c232 realtime The results show that various magnetospheric activities are almost reproduced qualitatively They also give us information how geomagnetic disturbances develop in the magnetosphere in relation with the ionosphere From the viewpoint of space weather the real-time simulation helps us to understand the whole image in the current condition of the magnetosphere To evaluate the simulation results we compare the AE index derived from the simulation and observations In the case of isolated substorms the indices almost agreed well in both timing and intensities In other cases the simulation can predict general activities although the exact timing of the onset of substorms and intensities did not always agree By analyzing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.476.2465O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.476.2465O"><span>The <span class="hlt">solar</span> <span class="hlt">wind</span> in time: a change in the behaviour of older <span class="hlt">winds</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Fionnagáin, D.; Vidotto, A. A.</p> <p>2018-05-01</p> <p>In this paper, we model the <span class="hlt">wind</span> of <span class="hlt">solar</span> analogues at different ages to investigate the evolution of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Recently, it has been suggested that <span class="hlt">winds</span> of <span class="hlt">solar</span> type stars might undergo a change in properties at old ages, whereby stars older than the Sun would be less efficient in carrying away angular momentum than what was traditionally believed. Adding to this, recent observations suggest that old <span class="hlt">solar</span>-type stars show a break in coronal properties, with a steeper decay in X-ray luminosities and temperatures at older ages. We use these X-ray observations to constrain the thermal acceleration of <span class="hlt">winds</span> of <span class="hlt">solar</span> analogues. Our sample is based on the stars from the `Sun in Time' project with ages between 120 and 7000 Myr. The break in X-ray properties leads to a break in <span class="hlt">wind</span> mass-loss rates (\\dot{M}) at roughly 2 Gyr, with \\dot{M} (t < 2 Gyr) ∝ t-0.74 and \\dot{M} (t > 2 Gyr) ∝ t-3.9. This steep decay in \\dot{M} at older ages could be the reason why older stars are less efficient at carrying away angular momentum, which would explain the anomalously rapid rotation observed in older stars. We also show that none of the stars in our sample would have <span class="hlt">winds</span> dense enough to produce thermal emission above 1-2 GHz, explaining why their radio emissions have not yet been detected. Combining our models with dynamo evolution models for the magnetic field of the Earth, we find that, at early ages (≈100 Myr), our Earth had a magnetosphere that was three or more times smaller than its current size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910030156&hterms=Increased+entropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DIncreased%2Bentropy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910030156&hterms=Increased+entropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DIncreased%2Bentropy"><span>Shock heating of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whang, Y. C.; Liu, Shaoliang; Burlaga, L. F.</p> <p>1990-01-01</p> <p>The role played by shocks in heating <span class="hlt">solar-wind</span> plasma is investigated using data on 413 shocks which were identified from the plasma and magnetic-field data collected between 1973 and 1982 by Pioneer and Voyager spacecraft. It is found that the average shock strength increased with the heliocentric distance outside 1 AU, reaching a maximum near 5 AU, after which the shock strength decreased with the distance; the entropy of the <span class="hlt">solar</span> <span class="hlt">wind</span> protons also reached a maximum at 5 AU. An MHD simulation model in which shock heating is the only heating mechanism available was used to calculate the entropy changes for the November 1977 event. The calculated entropy agreed well with the value calculated from observational data, suggesting that shocks are chiefly responsible for heating <span class="hlt">solar</span> <span class="hlt">wind</span> plasma between 1 and 15 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.P32A..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.P32A..01S"><span>The <span class="hlt">solar</span> <span class="hlt">wind</span> - Moon interaction discovered by MAP-PACE on KAGUYA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Y.; Yokota, S.; Tanaka, T.; Asamura, K.; Nishino, M. N.; Yamamoto, T.; Tsunakawa, H.; Shibuya, H.; Shimizu, H.; Takahashi, F.</p> <p>2009-12-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>, 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) <span class="hlt">Solar</span> <span class="hlt">wind</span> ions backscattered at the lunar surface, 2) <span class="hlt">Solar</span> <span class="hlt">wind</span> ions reflected by magnetic anomalies on the lunar surface, 3) Ions that are originating from the reflected / backscattered <span class="hlt">solar</span> <span class="hlt">wind</span> ions and are pick-up accelerated by the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> sputtering, <span class="hlt">solar</span> photon stimulated desorption, or micro-meteorite vaporization are accelerated by the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> ions impinged on the lunar surface. This discovery strongly restricts the possible generation mechanisms of the ionized alkali atmosphere around the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840005052','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840005052"><span>Quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span> dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pizzo, V. J.</p> <p>1983-01-01</p> <p>Progress in understanding the large scale dynamics of quasisteady, corotating <span class="hlt">solar</span> <span class="hlt">wind</span> structure was reviewed. The nature of the <span class="hlt">solar</span> <span class="hlt">wind</span> at large heliocentric distances preliminary calculations from a 2-D MHD model are used to demonstrate theoretical expectations of corotating structure out to 30 AU. It is found that the forward and reverse shocks from adjacent CIR's begin to interact at about 10 AU, producing new shock pairs flanking secondary CIR's. These sawtooth secondary CIR's interact again at about 20 AU and survive as visible entities to 30 AU. The model predicts the velocity jumps at the leading edge of the secondary CIR's at 30 AU should be very small but there should still be sizable variations in the thermodynamic and magnetic parameters. The driving dynamic mechanism in the distant <span class="hlt">solar</span> <span class="hlt">wind</span> is the relaxation of pressure gradients. The second topic is the influence of weak, nonimpulsive time dependence in quasisteady dynamics. It is suggested that modest large scale variations in the coronal flow speed on periods of several hours to a day may be responsible for many of the remaining discrepancies between theory and observation. Effects offer a ready explanation for the apparent rounding of stream fronts between 0.3 and 1.0 AU discovered by Helios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023337','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023337"><span><span class="hlt">Solar</span> and Heliospheric Data Requirements: Going Further Than L1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Szabo, A.</p> <p>2011-01-01</p> <p>Current operational space weather forecasting relies on <span class="hlt">solar</span> <span class="hlt">wind</span> observations made by the <span class="hlt">ACE</span> spacecraft located at the L1 point providing 30-40 minutes warning time. Some use is also made of SOHO and STEREO <span class="hlt">solar</span> imaging that potentially can give multiple days of warning time. However, our understanding of the propagation and evolution of <span class="hlt">solar</span> <span class="hlt">wind</span> transients is still limited resulting in a typical timing uncertainty of approximately 10 hours. In order to improve this critical understanding, a number of NASA missions are being planned. Specifically the <span class="hlt">Solar</span> Probe Plus and <span class="hlt">Solar</span> Orbiter missions will investigate the inner Heliospheric evolution of coronal mass ejections and the acceleration and propagation of <span class="hlt">solar</span> energetic particles. In addition, a number of multi-spacecraft concepts have been studied that have the potential to significantly improve the accuracy of long-term space weather forecasts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720012210','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720012210"><span>Collisionless <span class="hlt">solar</span> <span class="hlt">wind</span> protons: A comparison of kinetic and hydrodynamic descriptions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Leer, E.; Holzer, T. E.</p> <p>1971-01-01</p> <p>Kinetic and hydrodynamic descriptions of a collisionless <span class="hlt">solar</span> <span class="hlt">wind</span> proton gas are compared. Heat conduction and viscosity are neglected in the hydrodynamic formulation but automatically included in the kinetic formulation. The results of the two models are very nearly the same, indicating that heat conduction and viscosity are not important in the <span class="hlt">solar</span> <span class="hlt">wind</span> proton gas beyond about 0.1 AU. It is concluded that the hydrodynamic equations provide a valid description of the collisionless <span class="hlt">solar</span> <span class="hlt">wind</span> protons, and hence that future models of the quiet <span class="hlt">solar</span> <span class="hlt">wind</span> should be based on a hydrodynamic formulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840005044','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840005044"><span>Iron charge states observed in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ipavich, F. M.; Galvin, A. B.; Gloeckler, G.; Hovestadt, D.; Klecker, B.; Scholer, M.</p> <p>1983-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> measurements from the ULECA sensor of the Max-Planck-Institut/University of Maryland experiment on ISEE-3 are reported. The low energy section of approx the ULECA sensor selects particles by their energy per charge (over the range 3.6 keV/Q to 30 keV/Q) and simultaneously measures their total energy with two low-noise solid state detectors. <span class="hlt">Solar</span> <span class="hlt">wind</span> Fe charge state measurements from three time periods of high speed <span class="hlt">solar</span> <span class="hlt">wind</span> occurring during a post-shock flow and a coronal hole-associated high speed stream are presented. Analysis of the post-shock flow <span class="hlt">solar</span> <span class="hlt">wind</span> indicates the charge state distributions for Fe were peaked at approx +16, indicative of an unusually high coronal temperature (3,000,000 K). In contrast, the Fe charge state distribution observed in a coronal hole-associated high speed stream peaks at approx -9, indicating a much lower coronal temperature (1,400,000 K). This constitutes the first reported measurements of iron charge states in a coronal hole-associated high speed stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.3727S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.3727S"><span>Magnetosheath Propagation Time of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Directional Discontinuities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samsonov, A. A.; Sibeck, D. G.; Dmitrieva, N. P.; Semenov, V. S.; Slivka, K. Yu.; Å afránkova, J.; Němeček, Z.</p> <p>2018-05-01</p> <p>Observed delays in the ground response to <span class="hlt">solar</span> <span class="hlt">wind</span> directional discontinuities have been explained as the result of larger than expected magnetosheath propagation times. Recently, Samsonov et al. (2017, https://doi.org/10.1002/2017GL075020) showed that the typical time for a southward interplanetary magnetic field (IMF) turning to propagate across the magnetosheath is 14 min. Here by using a combination of magnetohydrodynamic simulations, spacecraft observations, and analytic calculations, we study the dependence of the propagation time on <span class="hlt">solar</span> <span class="hlt">wind</span> parameters and near-magnetopause cutoff speed. Increases in the <span class="hlt">solar</span> <span class="hlt">wind</span> speed result in greater magnetosheath plasma flow velocities, decreases in the magnetosheath thickness and, as a result, decreases in the propagation time. Increases in the IMF strength result in increases in the magnetosheath thickness and increases in the propagation time. Both magnetohydrodynamic simulations and observations suggest that propagation times are slightly smaller for northward IMF turnings. Magnetosheath flow deceleration must be taken into account when predicting the arrival times of <span class="hlt">solar</span> <span class="hlt">wind</span> structures at the dayside magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000110132&hterms=May+9th&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DMay%2B9th','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000110132&hterms=May+9th&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DMay%2B9th"><span>Electrons In The Low Density <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ogilvie, Keith W.; Desch, Michael; Fitzenreiter, Richard; Vondrak, Richard R. (Technical Monitor)</p> <p>2000-01-01</p> <p>The recent occurrence of an interval (May 9th to May 12th, 1999) of abnormally low density <span class="hlt">solar</span> <span class="hlt">wind</span> has drawn attention to such events. The SWE instrument on the <span class="hlt">Wind</span> spacecraft observed nine similar events between launch (November 1994) and August 1999: one in 1997, three in 1998, and five in January-August 1999. No such events were observed in 1996, the year of <span class="hlt">solar</span> minimum. This already suggests a strong dependence upon <span class="hlt">solar</span> activity. In this paper we discuss observations of the electron strahl, a strong anisotropy in the <span class="hlt">solar</span> <span class="hlt">wind</span> electrons above 60 eV directed along the magnetic field and observed continuously during the periods of low density in 1998 and 1999. When the <span class="hlt">solar</span> <span class="hlt">wind</span> density was less than 2/cc, the angular width of the strahl was below 3.5 degrees and the temperature deduced from the slope of the electron strahl phase density (as a function of energy in the energy range 200 to 800 eV) was 100 to 150 eV, equivalent to a typical coronal electron temperature. Three examples of this phenomenon, observed on Feb. 20- 22, April 26-27 and May 9-12, 1999, are discussed to show their similarity to one another. These electron observations are interpreted to show that the strahl occurs as a result of the conservation of the first adiabatic invariant, combined with the lack of coulomb collisions as suggested by Fairfield and Scudder, 1985.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AMT.....9.1063O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AMT.....9.1063O"><span>New temperature and pressure retrieval algorithm for high-resolution infrared <span class="hlt">solar</span> occultation spectroscopy: analysis and validation against <span class="hlt">ACE</span>-FTS and COSMIC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olsen, Kevin S.; Toon, Geoffrey C.; Boone, Chris D.; Strong, Kimberly</p> <p>2016-03-01</p> <p>Motivated by the initial selection of a high-resolution <span class="hlt">solar</span> occultation Fourier transform spectrometer (FTS) to fly to Mars on the ExoMars Trace Gas Orbiter, we have been developing algorithms for retrieving volume mixing ratio vertical profiles of trace gases, the primary component of which is a new algorithm and software for retrieving vertical profiles of temperature and pressure from the spectra. In contrast to Earth-observing instruments, which can rely on accurate meteorological models, a priori information, and spacecraft position, Mars retrievals require a method with minimal reliance on such data. The temperature and pressure retrieval algorithms developed for this work were evaluated using Earth-observing spectra from the Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>) FTS, a <span class="hlt">solar</span> occultation instrument in orbit since 2003, and the basis for the instrument selected for a Mars mission. <span class="hlt">ACE</span>-FTS makes multiple measurements during an occultation, separated in altitude by 1.5-5 km, and we analyse 10 CO2 vibration-rotation bands at each altitude, each with a different usable altitude range. We describe the algorithms and present results of their application and their comparison to the <span class="hlt">ACE</span>-FTS data products. The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) provides vertical profiles of temperature up to 40 km with high vertical resolution. Using six satellites and GPS radio occultation, COSMIC's data product has excellent temporal and spatial coverage, allowing us to find coincident measurements with <span class="hlt">ACE</span> with very tight criteria: less than 1.5 h and 150 km. We present an intercomparison of temperature profiles retrieved from <span class="hlt">ACE</span>-FTS using our algorithm, that of the <span class="hlt">ACE</span> Science Team (v3.5), and from COSMIC. When our retrievals are compared to <span class="hlt">ACE</span>-FTS v3.5, we find mean differences between -5 and +2 K and that our retrieved profiles have no seasonal or zonal biases but do have a warm bias in the stratosphere and a cold bias in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SSRv..210..227C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SSRv..210..227C"><span>Minimal Magnetic States of the Sun and the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Implications for the Origin of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cliver, E. W.; von Steiger, R.</p> <p>2017-09-01</p> <p>During the last decade it has been proposed that both the Sun and the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> activity during the recent minimum for the origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH23D2677G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH23D2677G"><span>CDPP supporting tools to <span class="hlt">Solar</span> Orbiter and Parker <span class="hlt">Solar</span> Probe data exploitation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Genot, V. N.; Cecconi, B.; Dufourg, N.; Gangloff, M.; André, N.; Bouchemit, M.; Jacquey, C.; Pitout, F.; Rouillard, A.; Nathanaël, J.; Lavraud, B.; Durand, J.; Tao, C.; Buchlin, E.; Witasse, O. G.</p> <p>2017-12-01</p> <p>In recent years the French Centre de Données de la Physique des Plasmas (CDPP) has extended its data analysis capability by designing a number of new tools. In the <span class="hlt">solar</span> and heliospheric contexts, and in direct support to the forthcoming <span class="hlt">solar</span> ESA and NASA missions in these fields, these tools comprise of the Propagation Tool which helps linking <span class="hlt">solar</span> perturbations observed both in remote and in-situ data; this is achieved through direct connection to the companion <span class="hlt">solar</span> database MEDOC and the CDPP AMDA database. More recently, in the frame of Europlanet 2020 RI, a 1D MHD <span class="hlt">solar</span> <span class="hlt">wind</span> propagation code (Tao et al., 2005) has been interfaced to provide real time <span class="hlt">solar</span> <span class="hlt">wind</span> monitors at cruising probes and planetary environments using <span class="hlt">ACE</span> real time data as inputs (Heliopropa service). Finally, simulations, models and data may be combined and visualized in a 3D context with 3DView. This presentation will overview the various functionalities of these tools and provide examples, in particular a 'CME tracking' case recently published (Witasse et al., 2017). Europlanet 2020 RI has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.3690K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.3690K"><span>The distinct character of anisotropy and intermittency in inertial and kinetic range <span class="hlt">solar</span> <span class="hlt">wind</span> plasma turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kiyani, Khurom; Chapman, Sandra; Osman, Kareem; Sahraoui, Fouad; Hnat, Bogdan</p> <p>2014-05-01</p> <p>The anisotropic nature of the scaling properties of <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic turbulence fluctuations is investigated scale by scale using high cadence in situ magnetic field measurements from the Cluster, <span class="hlt">ACE</span> and STEREO spacecraft missions in both fast and slow quiet <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. The data span five decades in scales from the inertial range to the electron Larmor radius. We find a clear transition in scaling behaviour between the inertial and kinetic range of scales, which provides a direct, quantitative constraint on the physical processes that mediate the cascade of energy through these scales. In the inertial (magnetohydrodynamic) range the statistical nature of turbulent fluctuations are known to be anisotropic, both in the vector components of the magnetic field fluctuations (variance anisotropy) and in the spatial scales of these fluctuations (wavevector or k-anisotropy). We show for the first time that, when measuring parallel to the local magnetic field direction, the full statistical signature of the magnetic and Elsasser field fluctuations is that of a non-Gaussian globally scale-invariant process. This is distinct from the classic multi-exponent statistics observed when the local magnetic field is perpendicular to the flow direction. These observations suggest the weakness, or absence, of a parallel magnetofluid turbulence energy cascade. In contrast to the inertial range, there is a successive increase toward isotropy between parallel and transverse power at scales below the ion Larmor radius, with isotropy being achieved at the electron Larmor radius. Computing higher-order statistics, we show that the full statistical signature of both parallel, and perpendicular fluctuations at scales below the ion Larmor radius are that of an isotropic globally scale-invariant non-Gaussian process. Lastly, we perform a survey of multiple intervals of quiet <span class="hlt">solar</span> <span class="hlt">wind</span> sampled under different plasma conditions (fast, slow <span class="hlt">wind</span>; plasma beta etc.) and find that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22126712-hemispheric-asymmetries-polar-solar-wind-observed-ulysses-near-minima-solar-cycles','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22126712-hemispheric-asymmetries-polar-solar-wind-observed-ulysses-near-minima-solar-cycles"><span>HEMISPHERIC ASYMMETRIES IN THE POLAR <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> OBSERVED BY ULYSSES NEAR THE MINIMA OF <span class="hlt">SOLAR</span> CYCLES 22 AND 23</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ebert, R. W.; Dayeh, M. A.; Desai, M. I.</p> <p>2013-05-10</p> <p>We examined <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and interplanetary magnetic field (IMF) observations from Ulysses' first and third orbits to study hemispheric differences in the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF originating from the Sun's large polar coronal holes (PCHs) during the declining and minimum phase of <span class="hlt">solar</span> cycles 22 and 23. We identified hemispheric asymmetries in several parameters, most notably {approx}15%-30% south-to-north differences in averages for the <span class="hlt">solar</span> <span class="hlt">wind</span> density, mass flux, dynamic pressure, and energy flux and the radial and total IMF magnitudes. These differences were driven by relatively larger, more variable <span class="hlt">solar</span> <span class="hlt">wind</span> density and radial IMF betweenmore » {approx}36 Degree-Sign S-60 Degree-Sign S during the declining phase of <span class="hlt">solar</span> cycles 22 and 23. These observations indicate either a hemispheric asymmetry in the PCH output during the declining and minimum phase of <span class="hlt">solar</span> cycles 22 and 23 with the southern hemisphere being more active than its northern counterpart, or a <span class="hlt">solar</span> cycle effect where the PCH output in both hemispheres is enhanced during periods of higher <span class="hlt">solar</span> activity. We also report a strong linear correlation between these <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF parameters, including the periods of enhanced PCH output, that highlight the connection between the <span class="hlt">solar</span> <span class="hlt">wind</span> mass and energy output and the Sun's magnetic field. That these enhancements were not matched by similar sized variations in <span class="hlt">solar</span> <span class="hlt">wind</span> speed points to the mass and energy responsible for these increases being added to the <span class="hlt">solar</span> <span class="hlt">wind</span> while its flow was subsonic.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH32A..03A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH32A..03A"><span>A Deeper Understanding of Stability in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Applying Nyquist's Instability Criterion to <span class="hlt">Wind</span> Faraday Cup Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alterman, B. L.; Klein, K. G.; Verscharen, D.; Stevens, M. L.; Kasper, J. C.</p> <p>2017-12-01</p> <p>Long duration, in situ data sets enable large-scale statistical analysis of free-energy-driven instabilities in the <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">Wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> stability. Using collisional age measurements, we predict the stability of the <span class="hlt">solar</span> <span class="hlt">wind</span> close to the sun. Accounting for the free-energy from the three most common ion populations in the <span class="hlt">solar</span> <span class="hlt">wind</span>, our approach provides a more complete characterization of <span class="hlt">solar</span> <span class="hlt">wind</span> stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM11B2317B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM11B2317B"><span>Dynamics of Magnetopause Reconnection in Response to Variable <span class="hlt">Solar</span> <span class="hlt">Wind</span> Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berchem, J.; Richard, R. L.; Escoubet, C. P.; Pitout, F.</p> <p>2017-12-01</p> <p>Quantifying the dynamics of magnetopause reconnection in response to variable <span class="hlt">solar</span> <span class="hlt">wind</span> driving is essential to advancing our predictive understanding of the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span>/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 <span class="hlt">solar</span> <span class="hlt">wind</span>/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 <span class="hlt">solar</span> <span class="hlt">wind</span> discontinuities on the magnetopause and examine how the recent history of the interaction of the magnetospheric boundary with <span class="hlt">solar</span> <span class="hlt">wind</span> discontinuities can modify the dynamics of magnetopause reconnection in response to the <span class="hlt">solar</span> <span class="hlt">wind</span> input.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4604519','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4604519"><span>Impacts of <span class="hlt">wind</span> stilling on <span class="hlt">solar</span> radiation variability in China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lin, Changgui; Yang, Kun; Huang, Jianping; Tang, Wenjun; Qin, Jun; Niu, Xiaolei; Chen, Yingying; Chen, Deliang; Lu, Ning; Fu, Rong</p> <p>2015-01-01</p> <p><span class="hlt">Solar</span> dimming and <span class="hlt">wind</span> stilling (slowdown) are two outstanding climate changes occurred in China over the last four decades. The <span class="hlt">wind</span> stilling may have suppressed the dispersion of aerosols and amplified the impact of aerosol emission on <span class="hlt">solar</span> 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 <span class="hlt">solar</span> radiation (SSR) decreased considerably with <span class="hlt">wind</span> stilling in heavily polluted regions at a daily scale, indicating that <span class="hlt">wind</span> stilling can considerably amplify the aerosol extinction effect on SSR. A threshold value of 3.5 m/s for <span class="hlt">wind</span> speed is required to effectively reduce aerosols concentration. From this SSR dependence on <span class="hlt">wind</span> speed, we further derived proxies to quantify aerosol emission and <span class="hlt">wind</span> stilling amplification effects on SSR variations at a decadal scale. The results show that aerosol emission accounted for approximately 20% of the typical <span class="hlt">solar</span> dimming in China, which was amplified by approximately 20% by <span class="hlt">wind</span> stilling. PMID:26463748</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRA..113.7101V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRA..113.7101V"><span>Inherent length-scales of periodic <span class="hlt">solar</span> <span class="hlt">wind</span> number density structures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Viall, N. M.; Kepko, L.; Spence, H. E.</p> <p>2008-07-01</p> <p>We present an analysis of the radial length-scales of periodic <span class="hlt">solar</span> <span class="hlt">wind</span> number density structures. We converted 11 years (1995-2005) of <span class="hlt">solar</span> <span class="hlt">wind</span> number density data into radial length series segments and Fourier analyzed them to identify all spectral peaks with radial wavelengths between 72 (116) and 900 (900) Mm for slow (fast) <span class="hlt">wind</span> intervals. Our window length for the spectral analysis was 9072 Mm, approximately equivalent to 7 (4) h of data for the slow (fast) <span class="hlt">solar</span> <span class="hlt">wind</span>. We required that spectral peaks pass both an amplitude test and a harmonic F-test at the 95% confidence level simultaneously. From the occurrence distributions of these spectral peaks for slow and fast <span class="hlt">wind</span>, we find that periodic number density structures occur more often at certain radial length-scales than at others, and are consistently observed within each speed range over most of the 11-year interval. For the slow <span class="hlt">wind</span>, those length-scales are L ˜ 73, 120, 136, and 180 Mm. For the fast <span class="hlt">wind</span>, those length-scales are L ˜ 187, 270 and 400 Mm. The results argue for the existence of inherent radial length-scales in the <span class="hlt">solar</span> <span class="hlt">wind</span> number density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1255080-ion-driven-instabilities-solar-wind-wind-observations-march','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1255080-ion-driven-instabilities-solar-wind-wind-observations-march"><span>Ion-driven instabilities in the <span class="hlt">solar</span> <span class="hlt">wind</span>: <span class="hlt">Wind</span> observations of 19 March 2005</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Gary, S. Peter; Jian, Lan K.; Broiles, Thomas W.; ...</p> <p>2016-01-16</p> <p>Intervals of enhanced magnetic fluctuations have been frequently observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>. However, it remains an open question as to whether these waves are generated at the Sun and then transported outward by the <span class="hlt">solar</span> <span class="hlt">wind</span> or generated locally in the interplanetary medium. Magnetic field and plasma measurements from the <span class="hlt">Wind</span> spacecraft under slow <span class="hlt">solar</span> <span class="hlt">wind</span> conditions on 19 March 2005 demonstrate seven events of enhanced magnetic fluctuations at spacecraft-frame frequencies somewhat above the proton cyclotron frequency and propagation approximately parallel or antiparallel to the background magnetic field B o. The proton velocity distributions during these events are characterizedmore » by two components: a more dense, slower core and a less dense, faster beam. In conclusion, observed plasma parameters are used in a kinetic linear dispersion equation analysis for electromagnetic fluctuations at k x B o = 0; for two events the most unstable mode is the Alfvén-cyclotron instability driven by a proton component temperature anisotropy T ⊥/T || > 1 (where the subscripts denote directions relative to B o), and for three events the most unstable mode is the right-hand polarized magnetosonic instability driven primarily by ion component relative flows. Thus, both types of ion anisotropies and both types of instabilities are likely to be local sources of these enhanced fluctuation events in the <span class="hlt">solar</span> <span class="hlt">wind</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1255080','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1255080"><span>Ion-driven instabilities in the <span class="hlt">solar</span> <span class="hlt">wind</span>: <span class="hlt">Wind</span> observations of 19 March 2005</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Gary, S. Peter; Jian, Lan K.; Broiles, Thomas W.</p> <p></p> <p>Intervals of enhanced magnetic fluctuations have been frequently observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>. However, it remains an open question as to whether these waves are generated at the Sun and then transported outward by the <span class="hlt">solar</span> <span class="hlt">wind</span> or generated locally in the interplanetary medium. Magnetic field and plasma measurements from the <span class="hlt">Wind</span> spacecraft under slow <span class="hlt">solar</span> <span class="hlt">wind</span> conditions on 19 March 2005 demonstrate seven events of enhanced magnetic fluctuations at spacecraft-frame frequencies somewhat above the proton cyclotron frequency and propagation approximately parallel or antiparallel to the background magnetic field B o. The proton velocity distributions during these events are characterizedmore » by two components: a more dense, slower core and a less dense, faster beam. In conclusion, observed plasma parameters are used in a kinetic linear dispersion equation analysis for electromagnetic fluctuations at k x B o = 0; for two events the most unstable mode is the Alfvén-cyclotron instability driven by a proton component temperature anisotropy T ⊥/T || > 1 (where the subscripts denote directions relative to B o), and for three events the most unstable mode is the right-hand polarized magnetosonic instability driven primarily by ion component relative flows. Thus, both types of ion anisotropies and both types of instabilities are likely to be local sources of these enhanced fluctuation events in the <span class="hlt">solar</span> <span class="hlt">wind</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27818854','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27818854"><span>Ion-driven instabilities in the <span class="hlt">solar</span> <span class="hlt">wind</span>: <span class="hlt">Wind</span> observations of 19 March 2005.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gary, S Peter; Jian, Lan K; Broiles, Thomas W; Stevens, Michael L; Podesta, John J; Kasper, Justin C</p> <p>2016-01-01</p> <p>Intervals of enhanced magnetic fluctuations have been frequently observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>. But it remains an open question as to whether these waves are generated at the Sun and then transported outward by the <span class="hlt">solar</span> <span class="hlt">wind</span> or generated locally in the interplanetary medium. Magnetic field and plasma measurements from the <span class="hlt">Wind</span> spacecraft under slow <span class="hlt">solar</span> <span class="hlt">wind</span> conditions on 19 March 2005 demonstrate seven events of enhanced magnetic fluctuations at spacecraft-frame frequencies somewhat above the proton cyclotron frequency and propagation approximately parallel or antiparallel to the background magnetic field B o . The proton velocity distributions during these events are characterized by two components: a more dense, slower core and a less dense, faster beam. Observed plasma parameters are used in a kinetic linear dispersion equation analysis for electromagnetic fluctuations at k x B o  = 0; for two events the most unstable mode is the Alfvén-cyclotron instability driven by a proton component temperature anisotropy T ⊥ /T ||  > 1 (where the subscripts denote directions relative to B o ), and for three events the most unstable mode is the right-hand polarized magnetosonic instability driven primarily by ion component relative flows. Thus, both types of ion anisotropies and both types of instabilities are likely to be local sources of these enhanced fluctuation events in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5070513','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5070513"><span>Ion‐driven instabilities in the <span class="hlt">solar</span> <span class="hlt">wind</span>: <span class="hlt">Wind</span> observations of 19 March 2005</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jian, Lan K.; Broiles, Thomas W.; Stevens, Michael L.; Podesta, John J.; Kasper, Justin C.</p> <p>2016-01-01</p> <p>Abstract Intervals of enhanced magnetic fluctuations have been frequently observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>. But it remains an open question as to whether these waves are generated at the Sun and then transported outward by the <span class="hlt">solar</span> <span class="hlt">wind</span> or generated locally in the interplanetary medium. Magnetic field and plasma measurements from the <span class="hlt">Wind</span> spacecraft under slow <span class="hlt">solar</span> <span class="hlt">wind</span> conditions on 19 March 2005 demonstrate seven events of enhanced magnetic fluctuations at spacecraft‐frame frequencies somewhat above the proton cyclotron frequency and propagation approximately parallel or antiparallel to the background magnetic field B o. The proton velocity distributions during these events are characterized by two components: a more dense, slower core and a less dense, faster beam. Observed plasma parameters are used in a kinetic linear dispersion equation analysis for electromagnetic fluctuations at k x B o = 0; for two events the most unstable mode is the Alfvén‐cyclotron instability driven by a proton component temperature anisotropy T⊥/T|| > 1 (where the subscripts denote directions relative to B o), and for three events the most unstable mode is the right‐hand polarized magnetosonic instability driven primarily by ion component relative flows. Thus, both types of ion anisotropies and both types of instabilities are likely to be local sources of these enhanced fluctuation events in the <span class="hlt">solar</span> <span class="hlt">wind</span>. PMID:27818854</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070011399&hterms=lazarus&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070011399&hterms=lazarus&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlazarus"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Helium Abundance as a Function of Speed and Heliographic Latitude: Variation through a <span class="hlt">Solar</span> Cycle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kasper, J. C.; Stenens, M. L.; Stevens, M. L.; Lazarus, A. J.; Steinberg, J. T.; Ogilvie, Keith W.</p> <p>2006-01-01</p> <p>We present a study of the variation of the relative abundance of helium to hydrogen in the <span class="hlt">solar</span> <span class="hlt">wind</span> as a function of <span class="hlt">solar</span> <span class="hlt">wind</span> speed and heliographic latitude over the previous <span class="hlt">solar</span> 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 <span class="hlt">Wind</span> spacecraft between 1995 and 2005. The higher speed and time resolution of this study compared to an earlier work with the <span class="hlt">Wind</span> observations has led to the discovery of three new aspects of A(sub He), modulation during <span class="hlt">solar</span> minimum from mid-1995 to mid-1997. First, we find that for <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> maximum the A(sub He), dependences on speed and latitude disappear, and we interpret this as evidence of two source regions for slow <span class="hlt">solar</span> <span class="hlt">wind</span> in the ecliptic plane, one being the <span class="hlt">solar</span> minimum streamer belt and the other likely being active regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150010735','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150010735"><span>On Lunar Exospheric Column Densities and <span class="hlt">Solar</span> <span class="hlt">Wind</span> Access Beyond the Terminator from ROSAT Soft X-Ray Observations of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Charge Exchange</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>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.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20150010735'); toggleEditAbsImage('author_20150010735_show'); toggleEditAbsImage('author_20150010735_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20150010735_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20150010735_hide"></p> <p>2014-01-01</p> <p>We analyze the Rontgen satellite (ROSAT) position sensitive proportional counter soft X-ray image of the Moon taken on 29 June 1990 by examining the radial profile of the surface brightness in three wedges: two 19 deg wedges (one north and one south) 13-32 deg off the terminator toward the dark side and one wedge 38 deg wide centered on the antisolar direction. The radial profiles of both the north and the south wedges show significant limb brightening that is absent in the 38 deg wide antisolar wedge. An analysis of the soft X-ray intensity increase associated with the limb brightening shows that its magnitude is consistent with that expected due to <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange (SWCX) with the tenuous lunar atmosphere based on lunar exospheric models and hybrid simulation results of <span class="hlt">solar</span> <span class="hlt">wind</span> access beyond the terminator. Soft X-ray imaging thus can independently infer the total lunar limb column density including all species, a property that before now has not been measured, and provide a large-scale picture of the <span class="hlt">solar</span> <span class="hlt">wind</span>-lunar interaction. Because the SWCX signal appears to be dominated by exospheric species arising from <span class="hlt">solar</span> <span class="hlt">wind</span> implantation, this technique can also determine how the exosphere varies with <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. Now, along with Mars, Venus, and Earth, the Moon represents another <span class="hlt">solar</span> system body at which SWCX has been observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22520043-energy-dissipation-processes-solar-wind-turbulence','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22520043-energy-dissipation-processes-solar-wind-turbulence"><span>ENERGY DISSIPATION PROCESSES IN <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> TURBULENCE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wang, Y.; Wei, F. S.; Feng, X. S.</p> <p></p> <p>Turbulence is a chaotic flow regime filled by irregular flows. The dissipation of turbulence is a fundamental problem in the realm of physics. Theoretically, dissipation ultimately cannot be achieved without collisions, and so how turbulent kinetic energy is dissipated in the nearly collisionless <span class="hlt">solar</span> <span class="hlt">wind</span> is a challenging problem. Wave particle interactions and magnetic reconnection (MR) are two possible dissipation mechanisms, but which mechanism dominates is still a controversial topic. Here we analyze the dissipation region scaling around a <span class="hlt">solar</span> <span class="hlt">wind</span> MR region. We find that the MR region shows unique multifractal scaling in the dissipation range, while the ambientmore » <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence reveals a monofractal dissipation process for most of the time. These results provide the first observational evidences for intermittent multifractal dissipation region scaling around a MR site, and they also have significant implications for the fundamental energy dissipation process.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970022574','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970022574"><span>Self-Consistent and Time-Dependent <span class="hlt">Solar</span> <span class="hlt">Wind</span> Models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ong, K. K.; Musielak, Z. E.; Rosner, R.; Suess, S. T.; Sulkanen, M. E.</p> <p>1997-01-01</p> <p>We describe the first results from a self-consistent study of Alfven waves for the time-dependent, single-fluid magnetohydrodynamic (MHD) <span class="hlt">solar</span> <span class="hlt">wind</span> equations, using a modified version of the ZEUS MHD code. The <span class="hlt">wind</span> models we examine are radially symmetrical and magnetized; the initial outflow is described by the standard Parker <span class="hlt">wind</span> solution. Our study focuses on the effects of Alfven waves on the outflow and is based on solving the full set of the ideal nonlinear MHD equations. In contrast to previous studies, no assumptions regarding wave linearity, wave damping, and wave-flow interaction are made; thus, the models naturally account for the back-reaction of the <span class="hlt">wind</span> on the waves, as well as for the nonlinear interaction between different types of MHD waves. Our results clearly demonstrate when momentum deposition by Alfven waves in the <span class="hlt">solar</span> <span class="hlt">wind</span> can be sufficient to explain the origin of fast streams in <span class="hlt">solar</span> coronal holes; we discuss the range of wave amplitudes required to obtained such fast stream solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SoPh..289.1863S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SoPh..289.1863S"><span><span class="hlt">Solar</span> EUV Irradiance Measurements by the Auto-Calibrating EUV Spectrometers (Sol<span class="hlt">ACES</span>) Aboard the International Space Station (ISS)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidtke, G.; Nikutowski, B.; Jacobi, C.; Brunner, R.; Erhardt, C.; Knecht, S.; Scherle, J.; Schlagenhauf, J.</p> <p>2014-05-01</p> <p>Sol<span class="hlt">ACES</span> is part of the ESA <span class="hlt">SOLAR</span> ISS mission that started aboard the shuttle mission STS-122 on 7 February 2008. The instrument has recorded <span class="hlt">solar</span> extreme ultraviolet (EUV) irradiance from 16 to 150 nm during the extended <span class="hlt">solar</span> activity minimum and the beginning <span class="hlt">solar</span> cycle 24 with rising <span class="hlt">solar</span> activity and increasingly changing spectral composition. The <span class="hlt">SOLAR</span> mission has been extended from a period of 18 months to > 8 years until the end of 2016. Sol<span class="hlt">ACES</span> is operating three grazing incidence planar grating spectrometers and two three-current ionization chambers. The latter ones are considered as primary radiometric detector standards. Re-filling the ionization chambers with three different gases repeatedly and using overlapping band-pass filters, the absolute EUV fluxes are derived in these spectral intervals. This way the serious problem of continuing efficiency changes in space-borne instrumentation is overcome during the mission. Evaluating the three currents of the ionization chambers, the overlapping spectral ranges of the spectrometers and of the filters plus inter-comparing the results from the EUV photon absorption in the gases with different absorption cross sections, there are manifold instrumental possibilities to cross-check the results providing a high degree of reliability to the spectral irradiance derived. During the mission a very strong up-and-down variability of the spectrometric efficiency by orders of magnitude is observed. One of the effects involved is channeltron degradation. However, there are still open questions on other effects contributing to these changes. A survey of the measurements carried out and first results of the <span class="hlt">solar</span> spectral irradiance (SSI) data are presented. Inter-comparison with EUV data from other space missions shows good agreement such that the international effort has started to elaborate a complete set of EUV-SSI data taking into account all data available from 2008 to 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25628139','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25628139"><span>Direct evidence for kinetic effects associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Xiaojun; Wang, Yi; Wei, Fengsi; Feng, Xueshang; Deng, Xiaohua; Ma, Yonghui; Zhou, Meng; Pang, Ye; Wong, Hon-Cheng</p> <p>2015-01-28</p> <p>Kinetic effects resulting from the two-fluid physics play a crucial role in the fast collisionless reconnection, which is a process to explosively release massive energy stored in magnetic fields in space and astrophysical plasmas. In-situ observations in the Earth's magnetosphere provide solid consistence with theoretical models on the point that kinetic effects are required in the collisionless reconnection. However, all the observations associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection have been analyzed in the context of magnetohydrodynamics (MHD) although a lot of <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection exhausts have been reported. Because of the absence of kinetic effects and substantial heating, whether the reconnections are still ongoing when they are detected in the <span class="hlt">solar</span> <span class="hlt">wind</span> remains unknown. Here, by dual-spacecraft observations, we report a <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection with clear Hall magnetic fields. Its corresponding Alfvenic electron outflow jet, derived from the decouple between ions and electrons, is identified, showing direct evidence for kinetic effects that dominate the collisionless reconnection. The turbulence associated with the exhaust is a kind of background <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence, implying that the reconnection generated turbulence has not much developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...804L..41T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...804L..41T"><span>Inertial Range Turbulence of Fast and Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span> at 0.72 AU and <span class="hlt">Solar</span> Minimum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teodorescu, Eliza; Echim, Marius; Munteanu, Costel; Zhang, Tielong; Bruno, Roberto; Kovacs, Peter</p> <p>2015-05-01</p> <p>We investigate Venus Express observations of magnetic field fluctuations performed systematically in the <span class="hlt">solar</span> <span class="hlt">wind</span> at 0.72 Astronomical Units (AU), between 2007 and 2009, during the deep minimum of <span class="hlt">solar</span> 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 <span class="hlt">wind</span>, 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and -1.65 for slow <span class="hlt">wind</span>. Compared to the corresponding average slopes at 1 AU, the PSDs are shallower at 0.72 AU for slow <span class="hlt">wind</span> conditions suggesting a steepening of the <span class="hlt">solar</span> <span class="hlt">wind</span> spectra between Venus and Earth. No significant time variation trend is observed for the spectral behavior of both the slow and fast <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002080','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002080"><span>Elemental and isotopic abundances in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Geiss, J.</p> <p>1972-01-01</p> <p>The use of collecting foils and lunar material to assay the isotopic composition of the <span class="hlt">solar</span> <span class="hlt">wind</span> is reviewed. Arguments are given to show that lunar surface correlated gases are likely to be most useful in studying the history of the <span class="hlt">solar</span> <span class="hlt">wind</span>, though the isotopic abundances are thought to give a good approximation to the <span class="hlt">solar</span> <span class="hlt">wind</span> composition. The results of the analysis of Surveyor material are also given. The conditions leading to a significant component of the interstellar gas entering the inner <span class="hlt">solar</span> system are reviewed and suggestions made for experimental searches for this fraction. A critical discussion is given of the different ways in which the basic <span class="hlt">solar</span> composition could be modified by fractionation taking place between the sun's surface and points of observation such as on the Moon or in interplanetary space. An extended review is made of the relation of isotopic and elemental composition of the interplanetary gas to the dynamic behavior of the <span class="hlt">solar</span> corona, especially processes leading to fractionation. Lastly, connection is made between the subject of composition, nucleosynthesis and the convective zone of the sun, and processes leading to modification of initial accretion of certain gases on the Earth and Moon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013339','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013339"><span>The Character of the <span class="hlt">Solar</span> <span class="hlt">Wind</span>, Surface Interactions, and Water</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farrell, William M.</p> <p>2011-01-01</p> <p>We discuss the key characteristics of the proton-rich <span class="hlt">solar</span> <span class="hlt">wind</span> and describe how it may interact with the lunar surface. We suggest that <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> plasma are in constant interaction with the lunar surface. As such, there is a <span class="hlt">solar</span>-lunar energy connection, where <span class="hlt">solar</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...832...66E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...832...66E"><span>Long-term Trends in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Proton Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elliott, Heather A.; McComas, David J.; DeForest, Craig E.</p> <p>2016-11-01</p> <p>We examine the long-term time evolution (1965-2015) of the relationships between <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperature (T p) and speed (V p) and between the proton density (n p) and speed using OMNI <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">wind</span> n p is highly correlated with the sunspot number, with a lag of approximately four years. The fast <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> density over a <span class="hlt">solar</span> cycle will create corresponding changes in the near-Earth space environment and the overall extent of the heliosphere.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15716946','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15716946"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> dynamic pressure and electric field as the main factors controlling Saturn's aurorae.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>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</p> <p>2005-02-17</p> <p>The interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with Earth's magnetosphere gives rise to the bright polar aurorae and to geomagnetic storms, but the relation between the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar-wind</span>-driven processes. This hypothesis, however, is tentative because of limited simultaneous <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetospheric measurements. Here we report <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. But in contrast to Earth, the main controlling factor appears to be <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, but the <span class="hlt">solar</span> <span class="hlt">wind</span> conditions that drive it differ from those that drive the Earth's magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760046362&hterms=planetary+boundaries&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dplanetary%2Bboundaries','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760046362&hterms=planetary+boundaries&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dplanetary%2Bboundaries"><span>Depletion of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma near a planetary boundary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zwan, B. J.; Wolf, R. A.</p> <p>1976-01-01</p> <p>A mathematical model is presented that describes the squeezing of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma out along interplanetary magnetic field lines in the region between the bow shock and the effective planetary boundary (in the case of the earth, the magnetopause). In the absence of local magnetic merging the squeezing process should create a 'depletion layer', a region of very low plasma density just outside the magnetopause. Numerical solutions are obtained for the dimensionless magnetohydrodynamic equations describing this depletion process for the case where the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field is perpendicular to the <span class="hlt">solar</span> <span class="hlt">wind</span> flow direction. For the case of the earth, the theory predicts that the density should be reduced by a factor exceeding 2 in a layer about 700-1300 km thick if the Alfven Mach number in the <span class="hlt">solar</span> <span class="hlt">wind</span>, is equal to 8. Scaling of the model calculations to Venus and Mars suggests layer thicknesses about 1/10 and 1/15 those of the earth, respectively, neglecting diffusion and ionospheric effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930032138&hterms=solar+two&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsolar%2Btwo','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930032138&hterms=solar+two&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsolar%2Btwo"><span>A parameter study of the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandbaek, Ornulf; Leer, Egil; Holzer, Thomas E.</p> <p>1992-01-01</p> <p>A two-fluid model of the <span class="hlt">solar</span> <span class="hlt">wind</span> was introduced by Sturrock and Hartle (1966) and Hartle and Sturrock (1968). In these studies the proton energy equation was integrated neglecting the heat conductive term. Later several authors solved the equations for the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span> model keeping the proton heat conductive term. Methods where the equations are integrated simultaneously outward and inward from the critical point were used. The equations were also integrated inward from a large heliocentric distance. These methods have been applied to cases with low coronal base electron densities and high base temperatures. In this paper we present a method of integrating the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span> equations using an iteration procedure where the equations are integrated separately and the proton flux is kept constant during the integrations. The technique is applicable for a wide range of coronal base densities and temperatures. The method is used to carry out a parameter study of the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080043891&hterms=luck&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dluck','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080043891&hterms=luck&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dluck"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Change Exchange from the Magnetosheath</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Snowden, Steve</p> <p>2008-01-01</p> <p>We report the results of a long (approximately 100 ks) XMM-Newton observation designed to observe <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange emission (SWCX) from Earth's magnetosheath. By luck, the observation took place during a period of minimal <span class="hlt">solar</span> <span class="hlt">wind</span> flux so the SWCX emission was also minimal. Never-the-less, there is a significant if not stunning correlation between the observed O VIII count rate and our model for magnetosheath emission. We also report on the observed O VII and O VII emission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19238948','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19238948"><span>Air emissions due to <span class="hlt">wind</span> and <span class="hlt">solar</span> power.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Katzenstein, Warren; Apt, Jay</p> <p>2009-01-15</p> <p>Renewables portfolio standards (RPS) encourage large-scale deployment of <span class="hlt">wind</span> and <span class="hlt">solar</span> electric power. Their power output varies rapidly, even when several sites are added together. In many locations, natural gas generators are the lowest cost resource available to compensate for this variability, and must ramp up and down quickly to keep the grid stable, affecting their emissions of NOx and CO2. We model a <span class="hlt">wind</span> or <span class="hlt">solar</span> photovoltaic plus gas system using measured 1-min time-resolved emissions and heat rate data from two types of natural gas generators, and power data from four <span class="hlt">wind</span> plants and one <span class="hlt">solar</span> plant. Over a wide range of renewable penetration, we find CO2 emissions achieve approximately 80% of the emissions reductions expected if the power fluctuations caused no additional emissions. Using steam injection, gas generators achieve only 30-50% of expected NOx emissions reductions, and with dry control NOx emissions increase substantially. We quantify the interaction between state RPSs and NOx constraints, finding that states with substantial RPSs could see significant upward pressure on NOx permit prices, if the gas turbines we modeled are representative of the plants used to mitigate <span class="hlt">wind</span> and <span class="hlt">solar</span> power variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DPPJ10090M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DPPJ10090M"><span>The Colorado <span class="hlt">Solar</span> <span class="hlt">Wind</span> Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Munsat, Tobin; Han, Jia; Horanyi, Mihaly; Ulibarri, Zach; Wang, Xu; Yeo, Lihsia</p> <p>2016-10-01</p> <p>The Colorado <span class="hlt">Solar</span> <span class="hlt">Wind</span> Experiment (CSWE) is a new device developed at the Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT) at the University of Colorado. This large ion source is for studies of the interaction of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma with planetary surfaces and cosmic dust, and for the investigation of plasma wake physics. With a plasma beam diameter of 12 cm at the source, ion energies of up to 1 keV, and ion flows of up to 1 mA/cm2, a large cross-section Kaufman Ion Source is used to create steady state plasma flow to model the <span class="hlt">solar</span> <span class="hlt">wind</span> in an experimental vacuum chamber. Chamber pressure can be reduced to 3e-5 Torr under operating conditions to suppress ion-neutral collisions and create a uniform ion velocity distribution. Diagnostic instruments such as a double Langmuir probe and an ion energy analyzer are mounted on a two-dimensional translation stage that allow the beam to be characterized throughout the chamber. Early experiments include the measurement of dust grain charging from the interaction with flowing plasma, and measurements of the plasma sheath created by the interaction of the flowing plasma impinging on a surface with a dipole magnetic field. This poster will describe the facility and the scientific results obtained to date.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4295037','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4295037"><span><span class="hlt">Solar</span> origins of <span class="hlt">solar</span> <span class="hlt">wind</span> properties during the cycle 23 <span class="hlt">solar</span> minimum and rising phase of cycle 24</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Luhmann, Janet G.; Petrie, Gordon; Riley, Pete</p> <p>2012-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> was originally envisioned using a simple dipolar corona/polar coronal hole sources picture, but modern observations and models, together with the recent unusual <span class="hlt">solar</span> cycle minimum, have demonstrated the limitations of this picture. The <span class="hlt">solar</span> surface fields in both polar and low-to-mid-latitude active region zones routinely produce coronal magnetic fields and related <span class="hlt">solar</span> <span class="hlt">wind</span> sources much more complex than a dipole. This makes low-to-mid latitude coronal holes and their associated streamer boundaries major contributors to what is observed in the ecliptic and affects the Earth. In this paper we use magnetogram-based coronal field models to describe the conditions that prevailed in the corona from the decline of cycle 23 into the rising phase of cycle 24. The results emphasize the need for adopting new views of what is ‘typical’ <span class="hlt">solar</span> <span class="hlt">wind</span>, even when the Sun is relatively inactive. PMID:25685422</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840005037','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840005037"><span>The average <span class="hlt">solar</span> <span class="hlt">wind</span> in the inner heliosphere: Structures and slow variations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schwenn, R.</p> <p>1983-01-01</p> <p>Measurements from the HELIOS <span class="hlt">solar</span> probes indicated that apart from <span class="hlt">solar</span> activity related disturbances there exist two states of the <span class="hlt">solar</span> <span class="hlt">wind</span> which might result from basic differences in the acceleration process: the fast <span class="hlt">solar</span> <span class="hlt">wind</span> (v 600 kms(-)1) emanating from magnetically open regions in the <span class="hlt">solar</span> corona and the "slow" <span class="hlt">solar</span> <span class="hlt">wind</span> (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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed. The long term variations of the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters along the <span class="hlt">solar</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...812..170T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...812..170T"><span>Thermalization of Heavy Ions in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tracy, Patrick J.; Kasper, Justin C.; Zurbuchen, Thomas H.; Raines, Jim M.; Shearer, Paul; Gilbert, Jason</p> <p>2015-10-01</p> <p>Observations of velocity distribution functions from the Advanced Composition Explorer/<span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer heavy ion composition instrument are used to calculate ratios of kinetic temperature and Coulomb collisional interactions of an unprecedented 50 ion species in the <span class="hlt">solar</span> <span class="hlt">wind</span>. These ions cover a mass per charge range of 1-5.5 amu/e and were collected in the time range of 1998-2011. We report the first calculation of the Coulomb thermalization rate between each of the heavy ion (A > 4 amu) species present in the <span class="hlt">solar</span> <span class="hlt">wind</span> along with protons (H+) and alpha particles (He2+). From these rates, we find that protons are the dominant source of Coulomb collisional thermalization for heavy ions in the <span class="hlt">solar</span> <span class="hlt">wind</span> and use this fact to calculate a collisional age for those heavy ion populations. The heavy ion thermal properties are well organized by this collisional age, but we find that the temperature of all heavy ions does not simply approach that of protons as Coulomb collisions become more important. We show that He2+ and C6+ follow a monotonic decay toward equal temperatures with protons with increasing collisional age, but O6+ shows a noted deviation from this monotonic decay. Furthermore, we show that the deviation from monotonic decay for O6+ occurs in <span class="hlt">solar</span> <span class="hlt">wind</span> of all origins, as determined by its Fe/O ratio. The observed differences in heavy ion temperature behavior point toward a local heating mechanism that favors ions depending on their charge and mass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120011917&hterms=WIND+STORMS&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DWIND%2BSTORMS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120011917&hterms=WIND+STORMS&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DWIND%2BSTORMS"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Charge Exchange During Geomagnetic Storms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Robertson, Ina P.; Cravens, Thomas E.; Sibeck, David G.; Collier, Michael R.; Kuntz, K. D.</p> <p>2012-01-01</p> <p>On March 31st. 2001, a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMe) employed a global magnetohydrodynamic (MHD) model to simulate the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interaction during the peak of this geomagnetic storm. Robertson et aL then modeled the expected 50ft X-ray emission due to <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on July 14, 2000 (Bastille Day). We again modeled X-ray emission due to <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X-ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1167251','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1167251"><span>Agua Caliente <span class="hlt">Wind/Solar</span> Project at Whitewater Ranch</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hooks, Todd; Stewart, Royce</p> <p>2014-12-16</p> <p>Agua Caliente Band of Cahuilla Indians (ACBCI) was awarded a grant by the Department of Energy (DOE) to study the feasibility of a <span class="hlt">wind</span> and/or <span class="hlt">solar</span> renewable energy project at the Whitewater Ranch (WWR) property of ACBCI. Red Mountain Energy Partners (RMEP) was engaged to conduct the study. The ACBCI tribal lands in the Coachella Valley have very rich renewable energy resources. The tribe has undertaken several studies to more fully understand the options available to them if they were to move forward with one or more renewable energy projects. With respect to the resources, the WWR property clearly hasmore » excellent <span class="hlt">wind</span> and <span class="hlt">solar</span> resources. The DOE National Renewable Energy Laboratory (NREL) has continued to upgrade and refine their library of resource maps. The newer, more precise maps quantify the resources as among the best in the world. The <span class="hlt">wind</span> and <span class="hlt">solar</span> technology available for deployment is also being improved. Both are reducing their costs to the point of being at or below the costs of fossil fuels. Technologies for energy storage and microgrids are also improving quickly and present additional ways to increase the <span class="hlt">wind</span> and/or <span class="hlt">solar</span> energy retained for later use with the network management flexibility to provide power to the appropriate locations when needed. As a result, renewable resources continue to gain more market share. The transitioning to renewables as the major resources for power will take some time as the conversion is complex and can have negative impacts if not managed well. While the economics for <span class="hlt">wind</span> and <span class="hlt">solar</span> systems continue to improve, the robustness of the WWR site was validated by the repeated queries of developers to place <span class="hlt">wind</span> and/or <span class="hlt">solar</span> there. The robust resources and improving technologies portends toward WWR land as a renewable energy site. The business case, however, is not so clear, especially when the potential investment portfolio for ACBCI has several very beneficial and profitable alternatives.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DPP.M9004E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DPP.M9004E"><span>Magnetic pumping of the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Egedal, Jan; Lichko, Emily; Daughton, William</p> <p>2015-11-01</p> <p>The transport of matter and radiation in the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980007565','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980007565"><span>Mapping the <span class="hlt">Solar</span> <span class="hlt">Wind</span> from its Source Region into the Outer Corona</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esser, Ruth</p> <p>1997-01-01</p> <p>Knowledge of the radial variation of the plasma conditions in the coronal source region of the <span class="hlt">solar</span> <span class="hlt">wind</span> is essential to exploring coronal heating and <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration mechanisms. The goal of the proposal was to determine as many plasma parameters in the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3627923','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3627923"><span>Three-dimensional exploration of the <span class="hlt">solar</span> <span class="hlt">wind</span> using observations of interplanetary scintillation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>TOKUMARU, Munetoshi</p> <p>2013-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. IPS measurements of the <span class="hlt">solar</span> <span class="hlt">wind</span> at a frequency of 327 MHz have been carried out regularly since the 1980s using the multi-station system of the <span class="hlt">Solar</span>-Terrestrial Environment Laboratory (STEL) of Nagoya University. This paper reviews new aspects of the <span class="hlt">solar</span> <span class="hlt">wind</span> revealed from our IPS observations. PMID:23391604</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH11B2453R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH11B2453R"><span>Global <span class="hlt">solar</span> magetic field organization in the extended corona: influence on the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and density over the cycle.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Réville, V.; Velli, M.; Brun, S.</p> <p>2017-12-01</p> <p>The dynamics of the <span class="hlt">solar</span> <span class="hlt">wind</span> depends intrinsically on the structure of the global <span class="hlt">solar</span> magnetic field, which undergoes fundamental changes over the 11yr <span class="hlt">solar</span> cycle. For instance, the <span class="hlt">wind</span> terminal velocity is thought to be anti-correlated with the expansion factor, a measure of how the magnetic field varies with height in the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> in a more detailed way, its influence on the <span class="hlt">solar</span> <span class="hlt">wind</span> properties remaining significant well beyond the source surface: we demonstrate this using 3D global MHD simulations of the <span class="hlt">solar</span> corona, constrained by surface magnetograms over half a <span class="hlt">solar</span> cycle (1989-2001). For models to comply with the constraints provided by observed characteristics of the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">wind</span> speed is anti-correlated with the mass flux, they must accurately describe expansion beyond the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> speed. We discuss the consequences of this result on the necessary acceleration profile of the <span class="hlt">solar</span> <span class="hlt">wind</span>, the location of the sonic point and of the energy deposition by Alfvén waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840004997','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840004997"><span>Interpretation of 3He variations in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coplan, M. A.; Ogilvie, K. W.; Geiss, J.; Bochsler, P.</p> <p>1983-01-01</p> <p>The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the <span class="hlt">solar</span> <span class="hlt">wind</span> almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of <span class="hlt">solar</span> activity cycle 21, the maximum period, and the beginning of the descent towards <span class="hlt">solar</span> minimum. Observations were made when the <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720044025&hterms=Parkin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DParkin','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720044025&hterms=Parkin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DParkin"><span>Measurements of lunar magnetic field interaction with the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dyal, P.; Parkin, C. W.; Snyder, C. W.; Clay, D. R.</p> <p>1972-01-01</p> <p>Study of the compression of the remanent lunar magnetic field by the <span class="hlt">solar</span> <span class="hlt">wind</span>, based on measurements of remanent magnetic fields at four Apollo landing sites and of the <span class="hlt">solar</span> <span class="hlt">wind</span> at two of these sites. Available data show that the remanent magnetic field at the lunar surface is compressed as much as 40% above its initial value by the <span class="hlt">solar</span> <span class="hlt">wind</span>, but the total remanent magnetic pressure is less than the stagnation pressure by a factor of six, implying that a local shock is not formed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003MmSAI..74..733A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003MmSAI..74..733A"><span>Acceleration region of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> in corona</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abbo, L.; Antonucci, E.; Mikić, Z.; Riley, P.; Dodero, M. A.; Giordano, S.</p> <p></p> <p>We present the results of a study concerning the physical parameters of the plasma of the extended corona in the low-latitude and equatorial regions, in order to investigate the sources of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> during the minimum of <span class="hlt">solar</span> activity. The equatorial streamer belt has been observed with the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO from August 19 to September 1, 1996. The spectroscopic diagnostic technique applied in this study, based on the OVI 1032, 1037 Ålines, allows us to determine both the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity and the electron density of the extended corona. The main result of the analysis is the identification of the acceleration region of the slow <span class="hlt">wind</span>, whose outflow velocity is measured in the range from 1.7 up to 3.5 <span class="hlt">solar</span> radii.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021297&hterms=solar+intensity+measurement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsolar%2Bintensity%2Bmeasurement','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021297&hterms=solar+intensity+measurement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsolar%2Bintensity%2Bmeasurement"><span>Radio interferometer measurements of turbulence in the inner <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spangler, S. R.; Sakurai, T.; Coles, William A.; Grall, R. R.; Harmon, J. K.</p> <p>1995-01-01</p> <p>Measurements can be made of Very Long Baseline Interferometer (VLBI) phase scintillations due to plasma turbulence in the <span class="hlt">solar</span> corona and <span class="hlt">solar</span> <span class="hlt">wind</span>. These measurements provide information on the spectrum and intensity of density fluctuations with scale sizes of a few hundred to several thousand kilometers. If we model the spatial power spectrum of the density fluctuations as P(sub delta n)(q) = C(sup 2)(sub N) q(sup -alpha), where q is the spatial wavenumber, these observations yield both alpha and the path-integrated value of C(sup 2)(sub N). The recently completed Very Long Baseline Array (VLBA) is capable of making such measurements over the heliocentric distance range from a few <span class="hlt">solar</span> radii to 60 <span class="hlt">solar</span> radii and beyond. This permits the determination with the same technique and instrument of the radial evolution of turbulent characteristics, as well as their dependence on <span class="hlt">solar</span> <span class="hlt">wind</span> transients, sector structure, etc. In this paper we present measurements of 13 sources observed at a wide range of <span class="hlt">solar</span> elongations, and at different times. These observations show that the coefficient C(sup 2(sub N), depends on heliocentric distance as approximately C(sup 2)(sub N) varies as (R/<span class="hlt">Solar</span> Radius)(sup -3.7). The radio derived power spectral characteristics are in agreement with in situ measurements by the Helios spacecraft for regions of slow <span class="hlt">solar</span> <span class="hlt">wind</span>, but fast <span class="hlt">solar</span> <span class="hlt">wind</span> does not have large enough density fluctuations to account for the magnitude of the observed scintillations. The observed radial dependence is consistent with a WKB-type evolution of the turbulence with heliocentric distance. Our data also show indication of turbulence enhancement associated with <span class="hlt">solar</span> <span class="hlt">wind</span> transients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.3900L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.3900L"><span>Saptio-temporal complementarity of <span class="hlt">wind</span> and <span class="hlt">solar</span> power in India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lolla, Savita; Baidya Roy, Somnath; Chowdhury, Sourangshu</p> <p>2015-04-01</p> <p><span class="hlt">Wind</span> and <span class="hlt">solar</span> 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 <span class="hlt">wind</span> and <span class="hlt">solar</span> 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 <span class="hlt">wind</span> and <span class="hlt">solar</span> 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. <span class="hlt">Wind</span> and <span class="hlt">solar</span> resources are estimated using the MERRA Reanalysis data for the 1979-2013 period. <span class="hlt">Solar</span> resources are calculated with a 20% conversion efficiency. <span class="hlt">Wind</span> resources are estimated using a 2 MW turbine power curve. Total resources are obtained by optimizing location and number of <span class="hlt">wind/solar</span> energy farms. Preliminary results show that the southern and western grids are more appropriate for cogeneration than the other grids. Many studies on <span class="hlt">wind-solar</span> 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.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...596A..42B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...596A..42B"><span>Mass-loading of the <span class="hlt">solar</span> <span class="hlt">wind</span> at 67P/Churyumov-Gerasimenko. Observations and modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Behar, E.; Lindkvist, J.; Nilsson, H.; Holmström, M.; Stenberg-Wieser, G.; Ramstad, R.; Götz, C.</p> <p>2016-11-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. Methods: We have analysed in situ ion and magnetic field data and combined this with hybrid modeling of the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the comet atmosphere. Results: The <span class="hlt">solar</span> <span class="hlt">wind</span> deflection is increasing with decreasing heliocentric distances, and exhibits very little deceleration. This is seen both in observations and in modeled <span class="hlt">solar</span> <span class="hlt">wind</span> protons. According to our model, energy and momentum are transferred from the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> flow. The energy gained by the cometary ions is a small fraction of the energy available in the <span class="hlt">solar</span> <span class="hlt">wind</span>. Conclusions: The deflection of the <span class="hlt">solar</span> <span class="hlt">wind</span> is the strongest and clearest signature of the mass-loading for a small, low-activity comet, whereas there is little deceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4308709','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4308709"><span>Direct evidence for kinetic effects associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xu, Xiaojun; Wang, Yi; Wei, Fengsi; Feng, Xueshang; Deng, Xiaohua; Ma, Yonghui; Zhou, Meng; Pang, Ye; Wong, Hon-Cheng</p> <p>2015-01-01</p> <p>Kinetic effects resulting from the two-fluid physics play a crucial role in the fast collisionless reconnection, which is a process to explosively release massive energy stored in magnetic fields in space and astrophysical plasmas. In-situ observations in the Earth's magnetosphere provide solid consistence with theoretical models on the point that kinetic effects are required in the collisionless reconnection. However, all the observations associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection have been analyzed in the context of magnetohydrodynamics (MHD) although a lot of <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection exhausts have been reported. Because of the absence of kinetic effects and substantial heating, whether the reconnections are still ongoing when they are detected in the <span class="hlt">solar</span> <span class="hlt">wind</span> remains unknown. Here, by dual-spacecraft observations, we report a <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection with clear Hall magnetic fields. Its corresponding Alfvenic electron outflow jet, derived from the decouple between ions and electrons, is identified, showing direct evidence for kinetic effects that dominate the collisionless reconnection. The turbulence associated with the exhaust is a kind of background <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence, implying that the reconnection generated turbulence has not much developed. PMID:25628139</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70021905','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70021905"><span>Estimated <span class="hlt">solar</span> <span class="hlt">wind</span>-implanted helium-3 distribution on the Moon</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Johnson, J. R.; Swindle, T.D.; Lucey, P.G.</p> <p>1999-01-01</p> <p>Among the <span class="hlt">solar</span> <span class="hlt">wind</span>-implanted volatiles present in the lunar regolith, 3 He is possibly the most valuable resource because of its potential as a fusion fuel. The abundance of 3 He in the lunar regolith at a given location depends on surface maturity, the amount of <span class="hlt">solar</span> <span class="hlt">wind</span> fluence, and titanium content, because ilmenite (FeTiO3) retains helium much better than other major lunar minerals. Surface maturity and TiO2 maps from Clementine multispectral data sets are combined here with a <span class="hlt">solar</span> <span class="hlt">wind</span> fluence model to produce a 3He abundance map of the Moon. Comparison of the predicted 3He values to landing site observations shows good correlation. The highest 3He abundances occur in the farside maria (due to greater <span class="hlt">solar</span> <span class="hlt">wind</span> fluence received) and in higher TiO2 nearside mare regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820024368','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820024368"><span>Calculation of <span class="hlt">solar</span> <span class="hlt">wind</span> flows about terrestrial planets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stahara, S. S.; Spreiter, J. R.</p> <p>1982-01-01</p> <p>A computational model was developed for the determination of the plasma and magnetic field properties of the global interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with terrestrial planetary magneto/ionospheres. The theoretical method is based on an established single fluid, steady, dissipationless, magnetohydrodynamic continuum model, and is appropriate for the calculation of supersonic, super Alfvenic <span class="hlt">solar</span> <span class="hlt">wind</span> flow past terrestrial planets. A summary is provided of the important research results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910043354&hterms=fisica&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfisica','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910043354&hterms=fisica&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfisica"><span>A study of the relationship between micropulsations and <span class="hlt">solar</span> <span class="hlt">wind</span> properties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yedidia, B. A.; Lazarus, A. J.; Vellante, M.; Villante, U.</p> <p>1991-01-01</p> <p>A year-long comparison between daily averages of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters obtained from the MIT experiment on IMP-8 and micropulsation measurements made by the Universita dell'Aquila has shown a correlation between <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed while the longer period activity tends to persist for longer intervals within high velocity <span class="hlt">solar</span> <span class="hlt">wind</span> streams. A comparison with simultaneous interplanetary magnetic field measurements supports the upstream origin of the observed ground pulsations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080022945','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080022945"><span>On the Relationship Between <span class="hlt">Solar</span> <span class="hlt">Wind</span> Speed, Geomagnetic Activity, and the <span class="hlt">Solar</span> Cycle Using Annual Values</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Robert M.; Hathaway, David H.</p> <p>2008-01-01</p> <p>The aa index can be decomposed into two separate components: the leading sporadic component due to <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed (especially between the residual component of aa and the <span class="hlt">solar</span> <span class="hlt">wind</span> speed, r = 0.865). Because cyclic averages of aa (and the residual component) have trended upward during cycles 11-23, cyclic averages of <span class="hlt">solar</span> <span class="hlt">wind</span> speed are inferred to have also trended upward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSH34A..02G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSH34A..02G"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Suprathermal Electron Strahl Width from 1.3 to 5.4 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goodrich, K. A.; Skoug, R. M.; Steinberg, J. T.; McComas, D. J.</p> <p>2010-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> suprathermal electron population typically includes an anisotropic anti-sunward field-aligned beam component, referred to as the strahl. As strahl electrons propagate anti-sunward in a decreasing interplanetary magnetic field, magnetic focusing acts to narrow the strahl beam width. At the same time, scattering processes work against the focusing and maintain strahl beams of finite width. The observed strahl width in the heliosphere is the result of the competition between focusing and scattering. The suprathermal electron strahl width and intensity observed by Ulysses from 1991 - 2008 have been newly examined. These observations cover radial distances between 1.3 and 5.4 AU, and span more than a <span class="hlt">solar</span> cycle. The strahl width and intensity are characterized by fitting pitch angle distributions to a function consisting of a Gaussian, peaked parallel (or anti-parallel) to the interplanetary field, plus a constant term. Approximately 50 - 65% of the Ulysses pitch angle spectra yield reasonable fits in preliminary analysis, indicating distributions that are well-described by this simple function. For most of the Ulysses observations at energies below 429 eV, the strahl width lies between 20o and 90o. The Ulysses results contrast with previously reported <span class="hlt">ACE</span> observations at 1 AU. In particular, the more distant Ulysses results appear shifted towards larger strahl widths, indicating that scattering becomes relatively more important than focusing beyond 1 AU. The Ulysses strahl widths are generally broader at heliospheric distances just beyond 2.5 AU than inside 2.5 AU. Between about 2.5 AU and 4.5 AU, the strahl width distribution varies little. Beyond 4.5 AU the strahl width again narrows, indicating that focusing begins to overcome scattering at these large distances. The distribution of strahl widths during the 1st (1992-1998) and 2nd (1998 - 2004) Ulysses polar orbits were compared, with little difference found. However a comparison of strahl widths</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15306802','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15306802"><span>Transport of <span class="hlt">solar</span> <span class="hlt">wind</span> into Earth's magnetosphere through rolled-up Kelvin-Helmholtz vortices.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hasegawa, H; Fujimoto, M; Phan, T-D; Rème, H; Balogh, A; Dunlop, M W; Hashimoto, C; Tandokoro, R</p> <p>2004-08-12</p> <p>Establishing the mechanisms by which the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar-wind</span> magnetic field conditions when the <span class="hlt">solar-wind</span> and geomagnetic fields are antiparallel at the low-latitude magnetopause. But the plasma content in the outer magnetosphere increases during northward <span class="hlt">solar-wind</span> magnetic field conditions, contrary to expectation if reconnection is dominant. Here we show that during northward <span class="hlt">solar-wind</span> magnetic field conditions-in the absence of active reconnection at low latitudes-there is a <span class="hlt">solar-wind</span> transport mechanism associated with the nonlinear phase of the Kelvin-Helmholtz instability. This can supply plasma sources for various space weather phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5261766-solar-wind-speed-he-nm-absorption-line-intensity','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5261766-solar-wind-speed-he-nm-absorption-line-intensity"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> speed and He I (1083 nm) absorption line intensity</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hakamada, Kazuyuki; Kojima, Masayoshi; Kakinuma, Takakiyo</p> <p>1991-04-01</p> <p>Since the pattern of the <span class="hlt">solar</span> <span class="hlt">wind</span> was relatively steady during Carrington rotations 1,748 through 1,752 in 1984, an average distribution of the <span class="hlt">solar</span> windspeed on a so-called source surface can be constructed by superposed epoch analysis of the <span class="hlt">wind</span> values estimated by the interplanetary scintillation observations. The average distribution of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed in regions where the temperature is low. Further, it is suggested that the efficiency of the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration decreases as the coronal temperature increases.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150010745&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DG%2526T','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150010745&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DG%2526T"><span>Anisotropic <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sputtering of the Lunar Surface Induced by Crustal Magnetic Anomalies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Poppe, A. R.; Sarantos, M.; Halekas, J. S.; Delory, G. T.; Saito, Y.; Nishino, M.</p> <p>2014-01-01</p> <p>The lunar exosphere is generated by several processes each of which generates neutral distributions with different spatial and temporal variability. <span class="hlt">Solar</span> <span class="hlt">wind</span> sputtering of the lunar surface is a major process for many regolith-derived species and typically generates neutral distributions with a cosine dependence on <span class="hlt">solar</span> zenith angle. Complicating this picture are remanent crustal magnetic anomalies on the lunar surface, which decelerate and partially reflect the <span class="hlt">solar</span> <span class="hlt">wind</span> before it strikes the surface. We use Kaguya maps of <span class="hlt">solar</span> <span class="hlt">wind</span> reflection efficiencies, Lunar Prospector maps of crustal field strengths, and published neutral sputtering yields to calculate anisotropic <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. Better understanding of <span class="hlt">solar</span> <span class="hlt">wind</span>/crustal anomaly interactions could potentially improve our results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060052480&hterms=solar+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bradiation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060052480&hterms=solar+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bradiation"><span>Spectral Absorption of <span class="hlt">Solar</span> Radiation by Aerosols during <span class="hlt">ACE</span>-Asia</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bergstrom, R. W.; Pilewskie, P.; Pommier, J.; Rabbette, M.; Russell, P. B.; Schmid, B.; Redermann, J.; Higurashi, A.; Nakajima, T.; Quinn, P. K.</p> <p>2004-01-01</p> <p>As part of the Asian Pacific Regional Aerosol Characterization Experiment (<span class="hlt">ACE</span>-Asia), the upward and downward spectral <span class="hlt">solar</span> radiant fluxes were measured with the Spectral <span class="hlt">Solar</span> Flux Radiometer (SSFR), and the aerosol optical depth was measured with the Ames Airborne Tracking Sunphotometer (AATS-14) aboard the Center for INterdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. IN this paper, we examine the data obtained for two cases: a moderately thick aerosol layer, 12 April, and a relatively thin aerosol case, 16 April 2001. ON both days, the Twin Otter flew vertical profiles in the Korean Strait southeast of Gosan Island. For both days we determine the aerosol spectral absorption of the layer and estimate the spectral aerosol absorption optical depth and single-scattering albedo. The results for 12 April show that the single-scattering albedo increases with wavelength from 0.8 at 400 nm to 0.95 at 900 nm and remains essentially constant from 950 to 1700 nm. On 16 April the amount of aerosol absorption was very low; however, the aerosol single-scattering albedo appears to decrease slightly with wavelength in the visible region. We interpret these results in light of the two absorbing aerosol species observed during the <span class="hlt">ACE</span>-asia study: mineral dust and black carbon. The results for 12 April are indicative of a mineral dust-black carbon mixture. The 16 April results are possibly caused by black carbon mixed with nonabsorbing pollution aerosols. For the 12 April case we attempt to estimate the relative contributions of the black carbon particles and the mineral dust particles. We compare our results with other estimates of the aerosol properties from a Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) satellite analysis and aerosol measurements made aboard the Twin Otter, aboard the National Oceanic and Atmospheric Administration Ronald H Brown ship, and at ground sites in Gosan and Japan. The results indicate a relatively complicated aerosol</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM13B2203T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM13B2203T"><span>Statistical Methods for Quantifying the Variability of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Transients of All Sizes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tindale, E.; Chapman, S. C.</p> <p>2016-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> is inherently variable across a wide range of timescales, from small-scale turbulent fluctuations to the 11-year periodicity induced by the <span class="hlt">solar</span> cycle. Each <span class="hlt">solar</span> cycle is unique, and this change in overall cycle activity is coupled from the Sun to Earth via the <span class="hlt">solar</span> <span class="hlt">wind</span>, leading to long-term trends in space weather. Our work [Tindale & Chapman, 2016] applies novel statistical methods to <span class="hlt">solar</span> <span class="hlt">wind</span> transients of all sizes, to quantify the variability of the <span class="hlt">solar</span> <span class="hlt">wind</span> associated with the <span class="hlt">solar</span> cycle. We use the same methods to link <span class="hlt">solar</span> <span class="hlt">wind</span> observations with those on the Sun and Earth. We use <span class="hlt">Wind</span> data to construct quantile-quantile (QQ) plots comparing the statistical distributions of multiple commonly used <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling parameters between the minima and maxima of <span class="hlt">solar</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> data, we extend the analysis to include <span class="hlt">solar</span> 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 <span class="hlt">solar</span> cycle-driven variability from the Sun through the <span class="hlt">solar</span> <span class="hlt">wind</span> and into the Earth's magnetosphere. Tindale, E. and S.C. Chapman (2016), Geophys. Res. Lett., 43(11), doi: 10</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010032395','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010032395"><span>Acceleration of the Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span> by Solitary Waves in Coronal Holes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ofman, Leon</p> <p>2001-01-01</p> <p>The purpose of this investigation is to develop a new model for the acceleration of the fast <span class="hlt">solar</span> <span class="hlt">wind</span> by nonlinear. time-dependent multidimensional MHD simulations of waves in <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. Specific goals of this proposal are to investigate the generation of nonlinear solitary-like waves and their effect on <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> coronal hole on the fast <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration with a more realistic model of a coronal hole and <span class="hlt">solar</span> boundary conditions. The ultimate goal of the three year study is to model the, fast <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000021483','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000021483"><span>Acceleration of the Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span> by Solitary Waves in Coronal Holes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ofman, Leon</p> <p>2000-01-01</p> <p>The purpose of this investigation is to develop a new model for the acceleration of the fast <span class="hlt">solar</span> <span class="hlt">wind</span> by nonlinear, time-dependent multidimensional MHD simulations of waves in <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. Specific goals of this proposal are to investigate the generation of nonlinear solitary-like waves and their effect on <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> coronal hole on the fast <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration with a more realistic model of a coronal hole and <span class="hlt">solar</span> boundary conditions. The ultimate goal of the three year study is to model the fast <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002053','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002053"><span>Conversion of magnetic field energy into kinetic energy in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whang, Y. C.</p> <p>1972-01-01</p> <p>The outflow of the <span class="hlt">solar</span> magnetic field energy (the radial component of the Poynting vector) per steradian is inversely proportional to the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity. It is a decreasing function of the heliocentric distance. When the magnetic field effect is included in the one-fluid model of the <span class="hlt">solar</span> <span class="hlt">wind</span>, the transformation of magnetic field energy into kinetic energy during the expansion process increases the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity at 1 AU by 17 percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170007773&hterms=solar+geometry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bgeometry','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170007773&hterms=solar+geometry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bgeometry"><span>Formation of Heliospheric Arcs of Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Higginson, A. K.; Antiochos, S. K.; Devore, C. R.; Wyper, P. F.; Zurbuchen, T. H.</p> <p>2017-01-01</p> <p>A major challenge in <span class="hlt">solar</span> and heliospheric physics is understanding the origin and nature of the so-called slow <span class="hlt">solar</span> <span class="hlt">wind</span>. The Sun's atmosphere is divided into magnetically open regions, known as coronal holes, where the plasma streams out freely and fills the <span class="hlt">solar</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> within and immediately adjacent to the HCS. Mysteriously, however, slow <span class="hlt">wind</span> 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-<span class="hlt">wind</span> observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22654484-formation-heliospheric-arcs-slow-solar-wind','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22654484-formation-heliospheric-arcs-slow-solar-wind"><span>Formation of Heliospheric Arcs of Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Higginson, A. K.; Zurbuchen, T. H.; Antiochos, S. K.</p> <p></p> <p>A major challenge in <span class="hlt">solar</span> and heliospheric physics is understanding the origin and nature of the so-called slow <span class="hlt">solar</span> <span class="hlt">wind</span>. The Sun’s atmosphere is divided into magnetically open regions, known as coronal holes, where the plasma streams out freely and fills the <span class="hlt">solar</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> within and immediately adjacent to the HCS. Mysteriously, however, slow <span class="hlt">wind</span> 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-<span class="hlt">wind</span> observations.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.nrel.gov/continuum/utility_scale/integrating_wind_solar.html','SCIGOVWS'); return false;" href="https://www.nrel.gov/continuum/utility_scale/integrating_wind_solar.html"><span>Integrating <span class="hlt">Wind</span> and <span class="hlt">Solar</span> on the Grid-NREL Analysis Leads the Way -</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>shown in color, but not including pink/IESO area.) Map provided by NREL Integrating <em><span class="hlt">Wind</span></em> and <span class="hlt">Solar</span> on the Grid-NREL Analysis Leads the Way NREL studies confirm big <em><span class="hlt">wind</span></em>, <span class="hlt">solar</span> potential for grid integration To fully harvest the nation's bountiful <em><span class="hlt">wind</span></em> and <span class="hlt">solar</span> resources, it is critical to know how much</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26ES...75a2007B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26ES...75a2007B"><span>Design of Hybrid <span class="hlt">Solar</span> and <span class="hlt">Wind</span> Energy Harvester for Fishing Boat</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banjarnahor, D. A.; Hanifan, M.; Budi, E. M.</p> <p>2017-07-01</p> <p>In southern beach of West Java, Indonesia, there are many villagers live as fishermen. They use small boats for fishing, in one to three days. Therefore, they need a fish preservation system. Fortunately, the area has high potential of <span class="hlt">solar</span> and <span class="hlt">wind</span> energy. This paper presents the design of a hybrid <span class="hlt">solar</span> and <span class="hlt">wind</span> energy harvester to power a refrigerator in the fishing boat. The refrigerator should keep the fish in 2 - 4 °C. The energy needed is 720 Wh daily. In the area, the daily average <span class="hlt">wind</span> velocity is 4.27 m/s and the sun irradiation is 672 W/m2. The design combined two 100W <span class="hlt">solar</span> panels and a 300W <span class="hlt">wind</span> turbine. The testing showed that the <span class="hlt">solar</span> panels can harvest 815 - 817 Wh of energy, while the <span class="hlt">wind</span> turbine can harvest 43 - 62 Wh of energy daily. Therefore, the system can fulfil the energy requirement in fishing boat, although the <span class="hlt">solar</span> panels were more dominant. To install the <span class="hlt">wind</span> turbine on the fishing-boat, a computational design had been conducted. The boat hydrostatic dimension was measured to determine its stability condition. To reach a stable equilibrium condition, the <span class="hlt">wind</span> turbine should be installed no more than 1.7 m of height.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000DPS....32.4701L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000DPS....32.4701L"><span>Venus and Mars Obstacles in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luhmann, J. G.; Mitchell, D. L.; Acuna, M. H.; Russell, C. T.; Brecht, S. H.; Lyon, J. G.</p> <p>2000-10-01</p> <p>Comparisons of the magnetosheaths of Venus and Mars contrast the relative simplicity of the Venus <span class="hlt">solar</span> <span class="hlt">wind</span> interaction and the ``Jekyll and Hyde" nature of the Mars interaction. Magnetometer observations from Mars Global Surveyor during the elliptical science phasing orbits and Pioneer Venus Orbiter in its normally elliptical orbit are compared, with various models used to compensate for the different near-polar periapsis of MGS and near-equator periapsis of PVO. Gasdynamic or MHD fluid models of flow around a conducting sphere provide a remarkably good desciption of the Venus case, and the Mars case when the strong Martian crustal magnetic anomalies are in the flow wake. In the case of Venus, large magnetosheath field fluctuations can be reliably tied to occurrence of a subsolar quasiparallel bow shock resulting from a small interplanetary field cone angle (angle between flow and field) upstream. At Mars one must also contend with such large fluctuations from the bow shock, but also from unstable <span class="hlt">solar</span> <span class="hlt">wind</span> proton distributions due to finite ion gyroradius effects, and from the complicated obstacle presented to the <span class="hlt">solar</span> <span class="hlt">wind</span> when the crustal magnetic anomalies are on the ram face or terminator. We attempt to distinguish between these factors at Mars, which are important for interpretation of the upcoming NOZOMI and Mars Express mission measurements. The results also provide more insights into a uniquely complex type of <span class="hlt">solar</span> system <span class="hlt">solar</span> <span class="hlt">wind</span> interaction involving crustal fields akin to the Moon's, combined with a Venus-like ionospheric obstacle.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......144G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......144G"><span>A hybrid reconfigurable <span class="hlt">solar</span> and <span class="hlt">wind</span> energy system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gadkari, Sagar A.</p> <p></p> <p>We study the feasibility of a novel hybrid <span class="hlt">solar-wind</span> hybrid system that shares most of its infrastructure and components. During periods of clear sunny days the system will generate electricity from the sun using a parabolic concentrator. The concentrator is formed by individual mirror elements and focuses the light onto high intensity vertical multi-junction (VMJ) cells. During periods of high <span class="hlt">wind</span> speeds and at night, the same concentrator setup will be reconfigured to channel the <span class="hlt">wind</span> into a <span class="hlt">wind</span> turbine which will be used to harness <span class="hlt">wind</span> energy. In this study we report on the feasibility of this type of <span class="hlt">solar/wind</span> hybrid energy system. The key mechanisms; optics, cooling mechanism of VMJ cells and air flow through the system were investigated using simulation tools. The results from these simulations, along with a simple economic analysis giving the levelized cost of energy for such a system are presented. An iterative method of design refinement based on the simulation results was used to work towards a prototype design. The levelized cost of the system achieved in the economic analysis shows the system to be a good alternative for a grid isolated site and could be used as a standalone system in regions of lower demand. The new approach to <span class="hlt">solar</span> <span class="hlt">wind</span> hybrid system reported herein will pave way for newer generation of hybrid systems that share common infrastructure in addition to the storage and distribution of energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH33B2774N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH33B2774N"><span>Heating of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ions via Cyclotron Resonance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navarro, R.; Moya, P. S.; Figueroa-Vinas, A.; Munoz, V.; Valdivia, J. A.</p> <p>2017-12-01</p> <p>Remote and in situ observations in the <span class="hlt">solar</span> <span class="hlt">wind</span> show that ion and electron velocity distributions persistently deviate from thermal equilibrium in the form of relative streaming between species components, temperature anisotropy, etc. These non-thermal features represent a source of free energy for the excitation of kinetic instabilities and fluctuations in the plasma. In this regard, it is believed that plasma particles can be heated, through a second order Fermi acceleration process, by multiple resonances with unstable counter-propagating field-aligned Ion-cyclotron waves. For multi-species plasmas, several collective wave modes participate in this process. In this work, we test this model by studying the percentage of ions that resonate with the waves modes described by the proper kinetic multi-species dispersion relation in a <span class="hlt">solar-wind</span>-like plasma composed of electrons, protons, and alpha particles. Numerical results are compared with <span class="hlt">WIND</span> spacecraft data to test its relevance for the existence of thresholds for the preferential perpendicular heating of He+2 ions as observed in the <span class="hlt">solar</span> <span class="hlt">wind</span> fast streams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010046973&hterms=kellogg&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dkellogg','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010046973&hterms=kellogg&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dkellogg"><span>Ion Isotropy and Ion Resonant Waves in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Cassini Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kellogg, Paul J.; Gurnett, Donald A.; Hospodarsky, George B.; Kurth, William S.</p> <p>2001-01-01</p> <p>Electric fields in the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span> ions and the validity of MHD for the description of the <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH41F..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH41F..05K"><span>Integrating Multiple Approaches to Solving <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulence Problems (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karimabadi, H.; Roytershteyn, V.</p> <p>2013-12-01</p> <p>The ultimate understanding of the <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence must explain the physical process and their connection at all scales ranging from the largest down to electron kinetic scales. This is a daunting task and as a result a more piecemeal approach to the problem has been followed. For example, the role of each wave has been explored in isolation and in simulations with scales limited to those of the underlying waves. In this talk, we present several issues with this approach and offer an alternative with an eye towards more realistic simulations of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence. The main simulation techniques used have been MHD, Hall MHD, hybrid, fully kinetic, and gyrokinetic. We examine the limitations of each approach and their viability for studies of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence. Finally, the effect of initial conditions on the resulting turbulence and their comparison with <span class="hlt">solar</span> <span class="hlt">wind</span> are demonstrated through several kinetic simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhPl...25b3702M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhPl...25b3702M"><span>An analytical investigation: Effect of <span class="hlt">solar</span> <span class="hlt">wind</span> on lunar photoelectron sheath</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mishra, S. K.; Misra, Shikha</p> <p>2018-02-01</p> <p>The formation of a photoelectron sheath over the lunar surface and subsequent dust levitation, under the influence of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and continuous <span class="hlt">solar</span> radiation, has been analytically investigated. The photoelectron sheath characteristics have been evaluated using the Poisson equation configured with population density contributions from half Fermi-Dirac distribution of the photoemitted electrons and simplified Maxwellian statistics of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma; as a consequence, altitude profiles for electric potential, electric field, and population density within the photoelectron sheath have been derived. The expression for the accretion rate of sheath electrons over the levitated spherical particles using anisotropic photoelectron flux has been derived, which has been further utilized to characterize the charging of levitating fine particles in the lunar sheath along with other constituent photoemission and <span class="hlt">solar</span> <span class="hlt">wind</span> fluxes. This estimate of particle charge has been further manifested with lunar sheath characteristics to evaluate the altitude profile of the particle size exhibiting levitation. The inclusion of <span class="hlt">solar</span> <span class="hlt">wind</span> flux into analysis is noticed to reduce the sheath span and altitude of the particle levitation; the dependence of the sheath structure and particle levitation on the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma parameters has been discussed and graphically presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...850...45R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...850...45R"><span>Global <span class="hlt">Solar</span> Magnetic Field Organization in the Outer Corona: Influence on the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Speed and Mass Flux Over the Cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Réville, Victor; Brun, Allan Sacha</p> <p>2017-11-01</p> <p>The dynamics of the <span class="hlt">solar</span> <span class="hlt">wind</span> depends intrinsically on the structure of the global <span class="hlt">solar</span> magnetic field, which undergoes fundamental changes over the 11-year <span class="hlt">solar</span> cycle. For instance, the <span class="hlt">wind</span> terminal velocity is thought to be anti-correlated with the expansion factor, a measure of how the magnetic field varies with height in the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> in a more detailed way, its influence on the <span class="hlt">solar</span> <span class="hlt">wind</span> properties remaining significant well beyond the source surface. We demonstrate this using 3D global magnetohydrodynamic (MHD) simulations of the <span class="hlt">solar</span> corona, constrained by surface magnetograms over half a <span class="hlt">solar</span> cycle (1989-2001). A self-consistent expansion beyond the <span class="hlt">solar</span> <span class="hlt">wind</span> critical point (even up to 10 {R}⊙ ) makes our model comply with observed characteristics of the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">wind</span> speed. We also show that near activity minimum, the expansion in the higher corona has more influence on the <span class="hlt">wind</span> speed than the expansion below 2.5 {R}⊙ .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRA..113.8107Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRA..113.8107Z"><span>Statistical validation of a <span class="hlt">solar</span> <span class="hlt">wind</span> propagation model from 1 to 10 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zieger, Bertalan; Hansen, Kenneth C.</p> <p>2008-08-01</p> <p>A one-dimensional (1-D) numerical magnetohydrodynamic (MHD) code is applied to propagate the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> predictions. In this paper, we present an extensive analysis of the prediction efficiency, using 12 selected years of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> speed, typically in the late declining phase of the <span class="hlt">solar</span> cycle. Among the <span class="hlt">solar</span> <span class="hlt">wind</span> variables, the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> that is not included in the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.A42C0778B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.A42C0778B"><span>The Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>): Mission Overview</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bernath, P. F.; Boone, C.; Walker, K.; McLeod, S.; Nassar, R.</p> <p>2003-12-01</p> <p>The <span class="hlt">ACE</span> mission goals are: (1) to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with a particular emphasis on the Arctic region; (2) to explore the relationship between atmospheric chemistry and climate change; (3) to study the effects of biomass burning in the free troposphere; (4) to measure aerosol number density, size distribution and composition in order to reduce the uncertainties in their effects on the global energy balance. <span class="hlt">ACE</span> will make a comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols, and temperature by <span class="hlt">solar</span> occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) gives <span class="hlt">ACE</span> coverage of tropical, mid-latitudes and polar regions. The <span class="hlt">solar</span> occultation advantages are high sensitivity and self-calibration. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4100 cm-1) will measure the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. The <span class="hlt">ACE</span> concept is derived from the now-retired ATMOS FTS instrument, which flew on the Space Shuttle in 1985, 1992, 1993, 1994. Climate-chemistry coupling may lead to the formation of an Arctic ozone hole. <span class="hlt">ACE</span> will provide high quality data to confront these model predictions and will monitor polar chemistry as chlorine levels decline. The <span class="hlt">ACE</span>-FTS can measure water vapor and HDO in the tropical tropopause region to study dehydration and strat-trop exchange. The molecular signatures of massive forest fires will evident in the <span class="hlt">ACE</span> infrared spectra. The CO2 in our spectra can be used to either retrieve atmospheric pressure or (if the instrument pointing knowledge proves to be satisfactory) for an independent retrieval of a CO2 profile for carbon cycle science. Aerosols and clouds will be monitored using the extinction of <span class="hlt">solar</span> radiation at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....3257B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....3257B"><span>The Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>): Mission Overview</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bernath, P.</p> <p>2003-04-01</p> <p>The <span class="hlt">ACE</span> mission goals are: (1) to measure and to understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with a particular emphasis on the Arctic region; (2) to explore the relationship between atmospheric chemistry and climate change; (3) to study the effects of biomass burning in the free troposphere; (4) to measure aerosol number density, size distribution and composition in order to reduce the uncertainties in their effects on the global energy balance. <span class="hlt">ACE</span> will make a comprehensive set of simultaneous measurements of trace gases, thin clouds, aerosols, and temperature by <span class="hlt">solar</span> occultation from a satellite in low earth orbit. A high inclination (74 degrees) low earth orbit (650 km) will give <span class="hlt">ACE</span> coverage of tropical, mid-latitudes and polar regions. The <span class="hlt">solar</span> occultation advantages are high sensitivity and self-calibration. A high-resolution (0.02 cm-1) infrared Fourier Transform Spectrometer (FTS) operating from 2 to 13 microns (750-4100 cm-1) will measure the vertical distribution of trace gases, and the meteorological variables of temperature and pressure. The <span class="hlt">ACE</span> concept is derived from the now-retired ATMOS FTS instrument, which flew on the Space Shuttle in 1985, 1992, 1993, 1994. Climate-chemistry coupling may lead to the formation of an Arctic ozone hole. <span class="hlt">ACE</span> will provide high quality data to confront these model predictions and will monitor polar chemistry as chlorine levels decline. The <span class="hlt">ACE</span>-FTS can measure water vapor and HDO in the tropical tropopause region to study dehydration and strat-trop exchange. The molecular signatures of massive forest fires will evident in the <span class="hlt">ACE</span> infrared spectra. The CO_2 in our spectra can be used to either retrieve atmospheric pressure or (if the instrument pointing knowledge proves to be satisfactory) for an independent retrieval of a CO_2 profile for carbon cycle science. Aerosols and clouds will be monitored using the extinction of <span class="hlt">solar</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820047282&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D80%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820047282&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D80%26Ntt%3Dlazarus"><span>Voyager observations of <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperature - 1-10 AU</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gazis, P. R.; Lazarus, A. J.</p> <p>1982-01-01</p> <p>Simultaneous measurements are made of the <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperatures by the Voyager 1 and 2 spacecraft, far from earth, and the IMP 8 spacecraft in earth orbit. This technique permits a separation of radial and temporal variations of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. The average value of the proton temperature between 1 and 9 AU is observed to decrease as r (the heliocentric radius) to the -(0.7 + or - 0.2). This is slower than would be expected for adiabatic expansion. A detailed examination of the <span class="hlt">solar</span> <span class="hlt">wind</span> stream structure shows that considerable heating occurs at the interface between high and low speed streams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AIPC.1500..186W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AIPC.1500..186W"><span>Alfvén wave interactions in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Webb, G. M.; McKenzie, J. F.; Hu, Q.; le Roux, J. A.; Zank, G. P.</p> <p>2012-11-01</p> <p>Alfvén wave mixing (interaction) equations used in locally incompressible turbulence transport equations in the <span class="hlt">solar</span> <span class="hlt">wind</span> are analyzed from the perspective of linear wave theory. The connection between the wave mixing equations and non-WKB Alfven wave driven <span class="hlt">wind</span> theories are delineated. We discuss the physical wave energy equation and the canonical wave energy equation for non-WKB Alfven waves and the WKB limit. Variational principles and conservation laws for the linear wave mixing equations for the Heinemann and Olbert non-WKB <span class="hlt">wind</span> model are obtained. The connection with wave mixing equations used in locally incompressible turbulence transport in the <span class="hlt">solar</span> <span class="hlt">wind</span> are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..116.3229N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..116.3229N"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> driving and substorm triggering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newell, Patrick T.; Liou, Kan</p> <p>2011-03-01</p> <p>We compare <span class="hlt">solar</span> <span class="hlt">wind</span> driving and its changes for three data sets: (1) 4861 identifications of substorm onsets from satellite global imagers (Polar UVI and IMAGE FUV); (2) a similar number of otherwise random times chosen with a similar <span class="hlt">solar</span> <span class="hlt">wind</span> distribution (slightly elevated driving); (3) completely random times. Multiple measures of <span class="hlt">solar</span> <span class="hlt">wind</span> driving were used, including interplanetary magnetic field (IMF) Bz, the Kan-Lee electric field, the Borovsky function, and dΦMP/dt (all of which estimate dayside merging). Superposed epoch analysis verifies that the mean Bz has a northward turning (or at least averages less southward) starting 20 min before onset. We argue that the delay between IMF impact on the magnetopause and tail effects appearing in the ionosphere is about that long. The northward turning is not the effect of a few extreme events. The median field shows the same result, as do all other measures of <span class="hlt">solar</span> <span class="hlt">wind</span> driving. We compare the rate of northward turning to that observed after random times with slightly elevated driving. The subsequent reversion to mean is essentially the same between random elevations and substorms. To further verify this, we consider in detail the distribution of changes from the statistical peak (20 min prior to onset) to onset. For Bz, the mean change after onset is +0.14 nT (i.e., IMF becomes more northward), but the standard deviation is σ = 2.8 nT. Thus large changes in either direction are common. For EKL, the change is -15 nT km/s ± 830 nT km/s. Thus either a hypothesis predicting northward turnings or one predicting southward turnings would find abundant yet random confirming examples. Indeed, applying the Lyons et al. (1997) trigger criteria (excluding only the prior requirement of 22/30 min Bz < 0, which is often not valid for actual substorms) to these three sets of data shows that "northward turning triggers" occur in 23% of the random data, 24% of the actual substorms, and after 27% of the random elevations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810042382&hterms=history+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhistory%2Btheory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810042382&hterms=history+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhistory%2Btheory"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> flow past Venus - Theory and comparisons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spreiter, J. R.; Stahara, S. S.</p> <p>1980-01-01</p> <p>Advanced computational procedures are applied to an improved model of <span class="hlt">solar</span> <span class="hlt">wind</span> flow past Venus to calculate the locations of the ionopause and bow wave and the properties of the flowing ionosheath plasma in the intervening region. The theoretical method is based on a single-fluid, steady, dissipationless, magneto-hydrodynamic continuum model and is appropriate for the calculation of axisymmetric supersonic, super-Alfvenic <span class="hlt">solar</span> <span class="hlt">wind</span> flow past a nonmagnetic planet possessing a sufficiently dense ionosphere to stand off the flowing plasma above the subsolar point and elsewhere. Determination of time histories of plasma and magnetic field properties along an arbitrary spacecraft trajectory and provision for an arbitrary oncoming direction of the interplanetary <span class="hlt">solar</span> <span class="hlt">wind</span> have been incorporated in the model. An outline is provided of the underlying theory and computational procedures, and sample comparisons of the results are presented with observations from the Pioneer Venus orbiter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810025913&hterms=debye+length&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddebye%2Blength','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810025913&hterms=debye+length&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddebye%2Blength"><span>A comparison of <span class="hlt">solar</span> <span class="hlt">wind</span> and ionospheric ion acoustic waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kintner, P. M.; Kelley, M. C.</p> <p>1980-01-01</p> <p>Ion acoustic waves produced during the Trigger experiment are compared to ion acoustic waves observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>. After normalizing to the Debye length the spectra are nearly identical, although the ionospheric wave relative energy density is 100 times larger than the <span class="hlt">solar</span> <span class="hlt">wind</span> case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SSRv..172..209E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SSRv..172..209E"><span>On the Role of Interchange Reconnection in the Generation of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Edmondson, J. K.</p> <p>2012-11-01</p> <p>The heating of the <span class="hlt">solar</span> corona and therefore the generation of the <span class="hlt">solar</span> <span class="hlt">wind</span>, remain an active area of <span class="hlt">solar</span> and heliophysics research. Several decades of in situ <span class="hlt">solar</span> <span class="hlt">wind</span> plasma observations have revealed a rich bimodal <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> flow regime. In order to elucidate the relationship between reconnection-driven coronal magnetic field structure and dynamics and the generation of the slow <span class="hlt">solar</span> <span class="hlt">wind</span>, this paper reviews the observations and phenomenology of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSH11A1502A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSH11A1502A"><span>Implications of the Deep Minimum for Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span> Origin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antiochos, S. K.; Mikic, Z.; Lionello, R.; Titov, V. S.; Linker, J. A.</p> <p>2009-12-01</p> <p>The origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> has long been one of the most important problems in <span class="hlt">solar</span>/heliospheric physics. Two observational constraints make this problem especially challenging. First, the slow <span class="hlt">wind</span> has the composition of the closed-field corona, unlike the fast <span class="hlt">wind</span> that originates on open field lines. Second, the slow <span class="hlt">wind</span> has substantial angular extent, of order 30 degrees, which is much larger than the widths observed for streamer stalks or the widths expected theoretically for a dynamic heliospheric current sheet. We propose that the slow <span class="hlt">wind</span> originates from an intricate network of narrow (possibly singular) open-field corridors that emanate from the polar coronal hole regions. Using topological arguments, we show that these corridors must be ubiquitous in the <span class="hlt">solar</span> corona. The total <span class="hlt">solar</span> eclipse in August 2008, near the lowest point of the Deep Minimum, affords an ideal opportunity to test this theory by using the ultra-high resolution Predictive Science's (PSI) eclipse model for the corona and <span class="hlt">wind</span>. Analysis of the PSI eclipse model demonstrates that the extent and scales of the open-field corridors can account for both the angular width of the slow <span class="hlt">wind</span> and its closed-field composition. We discuss the implications of our slow <span class="hlt">wind</span> theory for the structure of the corona and heliosphere at the Deep Minimum and describe further observational and theoretical tests. This work has been supported by the NASA HTP, SR&T, and LWS programs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1049597','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1049597"><span>Impacts of <span class="hlt">Wind</span> and <span class="hlt">Solar</span> on Fossil-Fueled Generators: Preprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lew, D.; Brinkman, G.; Kumar, N.</p> <p>2012-08-01</p> <p>High penetrations of <span class="hlt">wind</span> and <span class="hlt">solar</span> power will impact the operations of the remaining generators on the power system. Regional integration studies have shown that <span class="hlt">wind</span> and <span class="hlt">solar</span> may cause fossil-fueled generators to cycle on and off and ramp down to part load more frequently and potentially more rapidly. Increased cycling, deeper load following, and rapid ramping may result in wear-and-tear impacts on fossil-fueled generators that lead to increased capital and maintenance costs, increased equivalent forced outage rates, and degraded performance over time. Heat rates and emissions from fossil-fueled generators may be higher during cycling and ramping than during steady-statemore » operation. Many <span class="hlt">wind</span> and <span class="hlt">solar</span> integration studies have not taken these increased cost and emissions impacts into account because data have not been available. This analysis considers the cost and emissions impacts of cycling and ramping of fossil-fueled generation to refine assessments of <span class="hlt">wind</span> and <span class="hlt">solar</span> impacts on the power system.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170005311','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170005311"><span>Marshall Space Flight Center's <span class="hlt">Solar</span> <span class="hlt">Wind</span> Facility</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Whittlesey, P. L.</p> <p>2017-01-01</p> <p>Historically, NASA's Marshall Space Flight Center (MSFC) has operated a <span class="hlt">Solar</span> <span class="hlt">Wind</span> 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 <span class="hlt">Solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">Solar</span> Probe Plus program requirements. Data will be presented on the flux and energy ranges as well as beam stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22877159','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22877159"><span>Costs of <span class="hlt">solar</span> and <span class="hlt">wind</span> power variability for reducing CO2 emissions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lueken, Colleen; Cohen, Gilbert E; Apt, Jay</p> <p>2012-09-04</p> <p>We compare the power output from a year of electricity generation data from one <span class="hlt">solar</span> thermal plant, two <span class="hlt">solar</span> photovoltaic (PV) arrays, and twenty Electric Reliability Council of Texas (ERCOT) <span class="hlt">wind</span> farms. The analysis shows that <span class="hlt">solar</span> PV electricity generation is approximately one hundred times more variable at frequencies on the order of 10(-3) Hz than <span class="hlt">solar</span> thermal electricity generation, and the variability of <span class="hlt">wind</span> generation lies between that of <span class="hlt">solar</span> PV and <span class="hlt">solar</span> thermal. We calculate the cost of variability of the different <span class="hlt">solar</span> power sources and <span class="hlt">wind</span> 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 <span class="hlt">solar</span> PV generation at $8-11 per MWh. The cost of variability for <span class="hlt">solar</span> thermal generation is $5 per MWh, while that of <span class="hlt">wind</span> generation in ERCOT was found to be on average $4 per MWh. Variability adds ~$15/tonne CO(2) to the cost of abatement for <span class="hlt">solar</span> thermal power, $25 for <span class="hlt">wind</span>, and $33-$40 for PV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P53C2655T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P53C2655T"><span>Effects of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Pressure on Mercury's Exosphere: Hybrid Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Travnicek, P. M.; Schriver, D.; Orlando, T. M.; Hellinger, P.</p> <p>2017-12-01</p> <p>We study effects of the changed <span class="hlt">solar</span> <span class="hlt">wind</span> pressure on the precipitation of hydrogen on the Mercury's surface and on the formation of Mercury's magnetosphere. We carry out a set of global hybrid simulations of the Mercury's magnetosphere with the interplanetary magnetic field oriented in the equatorial plane. We change the <span class="hlt">solar</span> <span class="hlt">wind</span> pressure by changing the velocity of injected <span class="hlt">solar</span> <span class="hlt">wind</span> plasma (vsw = 2 vA,sw; vsw = 4 vA,sw; vsw = 6 vA,sw). For each of the cases we examine proton and electron precipitation on Mercury's surface and calculate yields of heavy ions released from Mercury's surface via various processes (namely: Photo-Stimulated Desorption, <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sputtering, and Electron Stimulated Desorption). We study circulation of the released ions within the Mercury's magnetosphere for the three cases.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021293&hterms=understand&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dunderstand','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021293&hterms=understand&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dunderstand"><span>Can we understand the turbulent <span class="hlt">solar</span> <span class="hlt">wind</span> via turbulent simulations?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grappin, R.; Mangeney, A.</p> <p>1995-01-01</p> <p>We attempt to assess the present understanding of the turbulent <span class="hlt">solar</span> <span class="hlt">wind</span> using numerical simulations. The <span class="hlt">solar</span> <span class="hlt">wind</span> may be considered as a kind of <span class="hlt">wind</span> tunnel with peculiar properties: the tunnel is spherical; the source of the <span class="hlt">wind</span> is rotating; and the medium is a plasma containing a large-scale magnetic field. These constraints lead to anisotropic dynamics of the fluctuations on the one hand, and to non-standard (turbulent?) transport properties of the global plasma on the other hand. How much of this rich physics can we approach today via numerical simulations?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21700869','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21700869"><span>A 15N-poor isotopic composition for the <span class="hlt">solar</span> system as shown by Genesis <span class="hlt">solar</span> <span class="hlt">wind</span> samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marty, B; Chaussidon, M; Wiens, R C; Jurewicz, A J G; Burnett, D S</p> <p>2011-06-24</p> <p>The Genesis mission sampled <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> system materials remain unknown. Isotopic analysis of a Genesis <span class="hlt">Solar</span> <span class="hlt">Wind</span> Concentrator target material shows that implanted <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent <span class="hlt">solar</span> system and accounts for the (15)N-depleted components observed in <span class="hlt">solar</span> system reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860041661&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DWind%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860041661&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DWind%2Benergy"><span>Global energy regulation in the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere-ionosphere system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sato, T.</p> <p>1985-01-01</p> <p>Some basic concepts which are essential in the understanding of global energy regulation in the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere-ionosphere system are introduced. The importance of line-tying concept is particularly emphasized in connection with the <span class="hlt">solar</span> <span class="hlt">wind</span> energy, energy release in the magnetosphere and energy dissipation in the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH52A..03V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH52A..03V"><span>The Slow and Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span> Boundary, Corotating Interaction Regions, and Coronal Mass Ejection observations with <span class="hlt">Solar</span> Probe Plus and <span class="hlt">Solar</span> Orbiter (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Velli, M. M.</p> <p>2013-12-01</p> <p>The <span class="hlt">Solar</span> Probe Plus and <span class="hlt">Solar</span> Orbiter missions have as part of their goals to understand the source regions of the <span class="hlt">solar</span> <span class="hlt">wind</span> and of the heliospheric magnetic field. In the heliosphere, the <span class="hlt">solar</span> <span class="hlt">wind</span> is made up of interacting fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetic fields in the heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090041830&hterms=rate+chemistry+experiment&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drate%2Bchemistry%2Bexperiment','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090041830&hterms=rate+chemistry+experiment&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drate%2Bchemistry%2Bexperiment"><span>First Measurements of the HCFC-142b Trend from Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>) <span class="hlt">Solar</span> Occultation Spectra</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rinsland, Curtis P.; Chiou, Linda; Boone,Chris; Bernath, Peter; Mahieu, Emmanuel</p> <p>2009-01-01</p> <p>The first measurement of the HCFC-142b (CH3CClF2) trend near the tropopause has been derived from volume mixing ratio (VMR) measurements at northern and southern hemisphere mid-latitudes for the 2004-2008 time period from spaceborne <span class="hlt">solar</span> occultation observations recorded at 0.02/cm resolution with the <span class="hlt">ACE</span> (atmospheric chemistry experiment) Fourier transform spectrometer. The HCFC-142b molecule is currently the third most abundant HCFC (hydrochlorofluorocarbon) in the atmosphere and <span class="hlt">ACE</span> measurements over this time span show a continuous rise in its volume mixing ratio. Monthly average measurements at northern and southern hemisphere midlatitudes have similar increase rates that are consistent with surface trend measurements for a similar time span. A mean northern hemisphere profile for the time span shows a near constant VMR at 8-20km altitude range, consistent on average for the same time span with in situ results. The nearly constant vertical VMR profile also agrees with model predictions of a long lifetime in the lower atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760017036','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760017036"><span>The 3-D <span class="hlt">solar</span> radioastronomy and the structure of the corona and the <span class="hlt">solar</span> <span class="hlt">wind</span>. [<span class="hlt">solar</span> probes of <span class="hlt">solar</span> activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Steinberg, J. L.; Caroubalos, C.</p> <p>1976-01-01</p> <p>The mechanism causing <span class="hlt">solar</span> radio bursts (1 and 111) is examined. It is proposed that a nonthermal energy source is responsible for the bursts; nonthermal energy is converted into electromagnetic energy. The advantages are examined for an out-of-the-ecliptic <span class="hlt">solar</span> probe mission, which is proposed as a means of stereoscopically viewing <span class="hlt">solar</span> radio bursts, <span class="hlt">solar</span> magnetic fields, coronal structure, and the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P54C..05K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P54C..05K"><span>Correlating <span class="hlt">Solar</span> <span class="hlt">Wind</span> Modulation with Ionospheric Variability at Mars from MEX and MAVEN Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kopf, A. J.; Morgan, D. D.; Halekas, J. S.; Ruhunusiri, S.; Gurnett, D. A.; Connerney, J. E. P.</p> <p>2017-12-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> can be observed. Previous studies have suggested a positive correlation, connecting ionospheric density to the <span class="hlt">solar</span> <span class="hlt">wind</span> proton flux, but depended on Earth-based measurements for <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field orientations. Here we extend this to more general <span class="hlt">solar</span> <span class="hlt">wind</span> conditions and examine how changes in the <span class="hlt">solar</span> <span class="hlt">wind</span> properties measured by MAVEN instruments correlate with ionospheric structure and dynamics observed simultaneously in MARSIS remote and local measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850032849&hterms=ici&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dici','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850032849&hterms=ici&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dici"><span>Interpretation of He-3 abundance variations in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coplan, M. A.; Ogilvie, K. W.; Bochsler, P.; Geiss, J.</p> <p>1984-01-01</p> <p>The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the <span class="hlt">solar</span> <span class="hlt">wind</span> almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of <span class="hlt">solar</span> activity cycle 21, the maximum period, and the beginning of the descent towards <span class="hlt">solar</span> minimum. Observations were made when the <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021428&hterms=micro+wind&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmicro%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021428&hterms=micro+wind&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmicro%2Bwind"><span>Observations of micro-turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> near the sun with interplanetary scintillation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yamauchi, Y.; Misawa, H.; Kojima, M.; Mori, H.; Tanaka, T.; Takaba, H.; Kondo, T.; Tokumaru, M.; Manoharan, P. K.</p> <p>1995-01-01</p> <p>Velocity and density turbulence of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and high-speed <span class="hlt">solar</span> <span class="hlt">wind</span>. Both of <span class="hlt">solar</span> <span class="hlt">winds</span> 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 <span class="hlt">solar</span> <span class="hlt">winds</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> is larger than that of low-speed <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050160464','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050160464"><span><span class="hlt">Solar</span> Cycle Variation and Multipoint Studies of ICME Properties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, C. T.</p> <p>2005-01-01</p> <p>The goal of the Living With a Star program is to understand the Sun-Earth connection sufficiently well that we can solve problems critical to life and society. This can most effectively be done in the short term using observations from our past and on-going programs. Not only can this approach solve some of the pressing issues but also it can provide ideas for the deployment of future spacecraft in the LWS program. The proposed effort uses data from NEAR, SOHO, <span class="hlt">Wind</span>, <span class="hlt">ACE</span> and Pioneer Venus in quadrature, multipoint, and <span class="hlt">solar</span> cycle studies to study the interplanetary coronal mass ejection and its role in the magnetic flux cycle of the Sun. ICMEs are most important to the LWS objectives because the <span class="hlt">solar</span> <span class="hlt">wind</span> conditions associated with these structures are the most geoeffective of any <span class="hlt">solar</span> <span class="hlt">wind</span> phenomena. Their ability to produce strong geomagnetic disturbances arises first because of their high speed. This high speed overtakes the ambient <span class="hlt">solar</span> <span class="hlt">wind</span> producing a bow shock wave similar to the terrestrial bow shock. In the new techniques we develop as part of this effort we exploit this feature of ICMEs. This shocked plasma has a greater velocity, higher density and stronger magnetic field than the ambient <span class="hlt">solar</span> <span class="hlt">wind</span>, conditions that can enhance geomagnetic activity. The driving ICME is a large magnetic structure expanding outward in the <span class="hlt">solar</span> <span class="hlt">wind</span> [Gosling, 19961. The ICMEs magnetic field is generally much higher than that in the ambient <span class="hlt">solar</span> <span class="hlt">wind</span> and the velocity is high. The twisted nature of the magnetic field in an ICME almost ensures that sometime during the ICME conditions favorable for geomagnetic storm initiation will occur.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/greenpower/gpp-webinar-market-outlook-and-innovations-wind-and-solar-power','PESTICIDES'); return false;" href="https://www.epa.gov/greenpower/gpp-webinar-market-outlook-and-innovations-wind-and-solar-power"><span>GPP Webinar: Market Outlook and Innovations in <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Power</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>Green Power Partnership webinar reviewing the state of the renewable energy industry as a whole, with a focus on <span class="hlt">wind</span> and <span class="hlt">solar</span> power and exploring recent marketplace innovations in <span class="hlt">wind</span> and <span class="hlt">solar</span> power and renewable energy purchases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740044930&hterms=heinemann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dheinemann','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740044930&hterms=heinemann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dheinemann"><span>Shapes of strong shock fronts in an inhomogeneous <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heinemann, M. A.; Siscoe, G. L.</p> <p>1974-01-01</p> <p>The shapes expected for <span class="hlt">solar</span>-flare-produced strong shock fronts in the <span class="hlt">solar</span> <span class="hlt">wind</span> have been calculated, large-scale variations in the ambient medium being taken into account. It has been shown that for reasonable ambient <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> may account for large deviations of shock normals from the radial direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040047164&hterms=topology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtopology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040047164&hterms=topology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtopology"><span>Coronal Magnetic Field Topology and Source of Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Guhathakurta, M.; Sittler, E.; Fisher, R.; McComas, D.; Thompson, B.</p> <p>1999-01-01</p> <p>We have developed a steady state, 2D semi-empirical MHD model of the <span class="hlt">solar</span> corona and the <span class="hlt">solar</span> <span class="hlt">wind</span> with many surprising results. This model for the first time shows, that the boundary between the fast and the slow <span class="hlt">solar</span> <span class="hlt">wind</span> as observed by Ulysses beyond 1 AU, is established in the low corona. The fastest <span class="hlt">wind</span> observed by Ulysses (680-780 km/s) originates from the polar coronal holes at 70 -90 deg. latitude at the Sun. Rapidly diverging magnetic field geometry accounts for the fast <span class="hlt">wind</span> reaching down to a latitude of +/- 30 deg. at the orbit of Earth. The gradual increase in the fast <span class="hlt">wind</span> observed by Ulysses, with latitude, can be explained by an increasing field strength towards the poles, which causes Alfven wave energy flux to increase towards the poles. Empirically, there is a direct relationship between this gradual increase in <span class="hlt">wind</span> speed and the expansion factor, f, computed at r greater than 20%. This relationship is inverse if f is computed very close to the Sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM31D..01N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM31D..01N"><span>Auroral Acceleration, <span class="hlt">Solar</span> <span class="hlt">Wind</span> Driving, and Substorm Triggering (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newell, P. T.; Liou, K.</p> <p>2010-12-01</p> <p>We use a data base of 4861 substorms identified by global UV images to investigate the substorm cycle dependence of various types of aurora, and to obtain new results on substorm triggering by external driving. Although all types of aurora increase at substorm onset, broadband (Alfvénic) aurora shows a particular association with substorms, and, especially, substorm onset. While diffuse electron and monoenergetic auroral precipitating power rises by 79% and 90% respectively following an onset, broadband aurora rises by 182%. In the first 10-15 minutes following onset, the power associated with Alfvénic acceleration is comparable to monoenergetic acceleration (also called “inverted-V” events). In general, this is not the case prior to onset, or indeed, during recovery. The rise time of the electron diffuse aurora following onset is much slower, about 50 minutes, and thus presumably extends into recovery. We also re-investigate the issue of <span class="hlt">solar</span> <span class="hlt">wind</span> triggering of substorms by considering not just changes in the <span class="hlt">solar</span> <span class="hlt">wind</span> prior to onset, but how the pattern of changes differs from random and comparable epochs. We verify that a preonset reduction of <span class="hlt">solar</span> <span class="hlt">wind</span> driving (“northward turning” in the simplest case of IMF Bz) holds for the superposed epoch mean of the ensemble. Moreover, this reduction is not the result of a small number of substorms with large changes. The reduction starts about 20 min prior to substorm onset, which, although a longer delay than previously suggested, is appropriate given the various propagation time delays involved. Next, we compare the IMF to random <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. Not surprisingly, <span class="hlt">solar</span> <span class="hlt">wind</span> driving prior to onset averages somewhat higher than random. Although about a quarter of substorms occur for steady northward IMF conditions, more general coupling functions such as the Kan-Lee electric field, the Borovosky function, or our dΦMP/dt, show very few substorms occur following weak dayside merging. We assembled a data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020069138&hterms=firenze&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfirenze','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020069138&hterms=firenze&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfirenze"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Characteristics from SOHO-Sun-Ulysses Quadrature Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Poletto, Giannina; Suess, Steve T.; Six, N. Frank (Technical Monitor)</p> <p>2002-01-01</p> <p>Over the past few years, we have been running SOHO (<span class="hlt">Solar</span> 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 (<span class="hlt">Solar</span> Ultraviolet Measurements of Emitted Radiation), CDS (Coronal Diagnostic Spectrometer) and UVCS (Ultraviolet Coronagraph Spectrometer) data to derive its physical characteristics. At interplanetary distances, SWICS (<span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer) and SWOOPS (<span class="hlt">Solar</span> <span class="hlt">Wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. In particular, a comparison between low-latitude and high-latitude <span class="hlt">wind</span>, 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 <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080031334&hterms=solar+energy+advantage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Benergy%2Badvantage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080031334&hterms=solar+energy+advantage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Benergy%2Badvantage"><span>Recent Insights into the Nature of Turbulence in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvun L.</p> <p>2008-01-01</p> <p>During the past several years, studies of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence using data from Cluster and other spacecraft, and results from new numerical simulations, have revealed new aspects of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence. I will try to highlight some of that research. At the shortest length scales and highest frequencies, there is renewed interest in determining how the turbulence dissipates, e.g., whether by kinetic Alfven waves or whistler turbulence. Finding observational evidence for exponential damping of <span class="hlt">solar</span> <span class="hlt">wind</span> fluctuations has proven challenging. New studies using a combination of flux gate and search coil magnetometer data from Cluster have extended this search (in the spacecraft frame of reference) to more than 10 Hertz. New models and simulations are also being used to study the dissipation. A detailed study of fluctuations in the magnetosheath suggests that turbulent dissipation could be occurring at very thin current sheets as had been suggested by two-dimensional MHD simulations more than 20 years ago. Data from the four Cluster spacecraft, now at their maximum separation of 10,000 km provide new opportunities to investigate the symmetry properties, scale lengths, and the relative proportion of magnetic energy in parallel and perpendicular wave numbers of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence. By utilizing well-calibrated electron data, it has been possible to take advantage of the tetrahedral separation of Cluster in the <span class="hlt">solar</span> <span class="hlt">wind</span> near apogee to measure directly the compressibility and vorticity of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029146&hterms=atmosphere+wind+profile&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Datmosphere%2Bwind%2Bprofile','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029146&hterms=atmosphere+wind+profile&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Datmosphere%2Bwind%2Bprofile"><span>Coupling of the coronal helium abundance to the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hansteen, Viggo H.; Leer, Egil; Holzer, Thomas E.</p> <p>1994-01-01</p> <p>Models of the transition region-corona-<span class="hlt">solar</span> <span class="hlt">wind</span> system are investigated in order to find the coronal helium abundance and to study the role played by coronal helium in controlling the <span class="hlt">solar</span> <span class="hlt">wind</span> proton flux. The thermal force on alpha-particles in the transition region sets the flow of helium into the corona. The frictional coupling between alpha-particles and protons and/or the electric polarization field determines the proton flux in the <span class="hlt">solar</span> <span class="hlt">wind</span> as well as the fate of the coronal helium content. The models are constructed by solving the time-dependent population and momentum equations for all species of hydrogen and helium in an atmosphere with a given temperature profile. Several temperature profiles are considered in order to very the roles of frictional coupling and electric polarization field in the <span class="hlt">solar</span> <span class="hlt">wind</span>, and the thermal force in the transition region. Steady-state solutions are found for coronae with a hydrogen flux at 1 AU of 1.0 x 10(exp 9)/cm(exp 2)/sec or larger. For coronae with lower hydrogen fluxes, the helium flux into the corona is larger than the flux 'pulled out' by the <span class="hlt">solar</span> <span class="hlt">wind</span> protons, and solutions with increasing coronal helium content are found. The timescale for forming a helium-filled corona, that may allow for a steady outflow, is long compared to the mixing time for the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002078','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002078"><span>Corotation of an intermittent <span class="hlt">solar</span> <span class="hlt">wind</span> source</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Croft, T. A.</p> <p>1972-01-01</p> <p>The measured electron content of the <span class="hlt">solar</span> <span class="hlt">wind</span> in mid-1970 exhibited a region of relatively high electron density that reappeared at intervals of about 27.8 days. It is shown that the repeating event cannot be reconciled with the concept of a long-enduring steady flow, even though the recurrence period is close to the rotation period of the sun. This evidence of transients is inferred from the short duration of each appearance of the interval of higher density; each should last for roughly one corotation interval if it is caused by a steady stream. The radio path was approximately 0.8 AU long, and the corotation interval exceeded 3 days. Other aspects of the content data patterns support the view that such transient events are common in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The mid-1970 repeating event is an unusually good example of the intermittent character of flow regions in the <span class="hlt">solar</span> <span class="hlt">wind</span> that fluctuate on a time scale of days but endure as identifiable regions for many months. A sputtering corotating source of thin <span class="hlt">solar</span> plasma streams could explain this series of events; it could also be explained in terms of a stream that is steady in density and speed but undulating north-south so that it passes into and out of the 0.8 AU radio path in a matter of a day or less.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSH22B..03H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH22B..03H"><span>IPS analysis on relationship among velocity, density and temperature of the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hayashi, K.; Tokumaru, M.; Fujiki, K.</p> <p>2015-12-01</p> <p>The IPS(Interplanetary Scintillation)-MHD(magnetohydrodynamics) tomography is a method we have developed to determine three-dimensional MHD solution of the <span class="hlt">solar</span> <span class="hlt">wind</span> that best matches the line-of-sight IPS <span class="hlt">solar-wind</span> 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 <span class="hlt">solar-wind</span> boundary map at 50 <span class="hlt">solar</span> radii. This forward model needs to assume <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> corona and heliosphere, and will help our understandings on roles of magnetic field in <span class="hlt">solar</span> <span class="hlt">wind</span> heating and acceleration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060009195&hterms=investigaciones+de+fisica&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dinvestigaciones%2Bde%2Bfisica','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060009195&hterms=investigaciones+de+fisica&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dinvestigaciones%2Bde%2Bfisica"><span>Spatial Correlation of <span class="hlt">Solar-Wind</span> Turbulence from Two-Point Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matthaeus, W. H.; Milano, L. J.; Dasso, S.; Weygand, J. M.; Smith, C. W.; Kivelson, M. G.</p> <p>2005-01-01</p> <p>Interplanetary turbulence, the best studied case of low frequency plasma turbulence, is the only directly quantified instance of astrophysical turbulence. Here, magnetic field correlation analysis, using for the first time only proper two-point, single time measurements, provides a key step in unraveling the space-time structure of interplanetary turbulence. Simultaneous magnetic field data from the <span class="hlt">Wind</span>, <span class="hlt">ACE</span>, and Cluster spacecraft are analyzed to determine the correlation (outer) scale, and the Taylor microscale near Earth's orbit.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120002024','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120002024"><span>Three-Fluid Magnetohydrodynamic Modeling of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> in the Outer Heliosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.</p> <p>2011-01-01</p> <p>We have developed a three-fluid, fully three-dimensional magnetohydrodynamic model of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma in the outer heliosphere as a co-moving system of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> protons, and <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=273864','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=273864"><span>Analysis of off-grid hybrid <span class="hlt">wind</span> turbine/<span class="hlt">solar</span> PV water pumping systems</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>While many remote water pumping systems exist (e.g. mechanical windmills, <span class="hlt">solar</span> photovoltaic , <span class="hlt">wind</span>-electric, diesel powered), very few combine both the <span class="hlt">wind</span> and <span class="hlt">solar</span> energy resources to possibly improve the reliability and the performance of the system. In this paper, off-grid <span class="hlt">wind</span> turbine (WT) a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002035','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002035"><span>Coronal magnetic fields and the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newkirk, G., Jr.</p> <p>1972-01-01</p> <p>Current information is presented on coronal magnetic fields as they bear on problems of the <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH23D2692D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH23D2692D"><span>Remote Sensing of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Density, Speed, and Temperature in the Region between the Sun and Parker <span class="hlt">Solar</span> Probe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davila, J. M.; Reginald, N. L.</p> <p>2017-12-01</p> <p>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 <span class="hlt">solar</span> atmosphere. This instrument will provide the first remote sensing measurement of the global <span class="hlt">solar</span> <span class="hlt">wind</span> temperature, density, and flow speed in the regions between 3 and 8 Rsun. It is in this region that the manority of the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration takes place, and where the ion compsition of the <span class="hlt">solar</span> <span class="hlt">wind</span> is "frozen in". This is also the region of the corona that links the surface of the Sun to the Parker <span class="hlt">Solar</span> Probe and to <span class="hlt">Solar</span> Orbiter. The observations suggested here would dramatically improve our understanding of <span class="hlt">solar</span> <span class="hlt">wind</span> formation and evolution in this critical region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130012782','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130012782"><span>Construction of <span class="hlt">Solar-Wind</span>-Like Magnetic Fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roberts, Dana Aaron</p> <p>2012-01-01</p> <p>Fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> fields tend to not only have velocities and magnetic fields correlated in the sense consistent with Alfven waves traveling from the Sun, but they also have the magnitude of the magnetic field remarkably constant despite their being broadband. This paper provides, for the first time, a method for constructing fields with nearly constant magnetic field, zero divergence, and with any specified power spectrum for the fluctuations of the components of the field. Every wave vector, k, is associated with two polarizations the relative phases of these can be chosen to minimize the variance of the field magnitude while retaining the\\random character of the fields. The method is applied to a case with one spatial coordinate that demonstrates good agreement with observed time series and power spectra of the magnetic field in the <span class="hlt">solar</span> <span class="hlt">wind</span>, as well as with the distribution of the angles of rapid changes (discontinuities), thus showing a deep connection between two seemingly unrelated issues. It is suggested that using this construction will lead to more realistic simulations of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence and of the propagation of energetic particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23383910','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23383910"><span>Ion kinetic scale in the <span class="hlt">solar</span> <span class="hlt">wind</span> observed.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Śafránková, Jana; Němeček, Zdeněk; Přech, Lubomír; Zastenker, Georgy N</p> <p>2013-01-11</p> <p>This Letter shows the first results from the <span class="hlt">solar</span> <span class="hlt">wind</span> monitor onboard the Spektr-R spacecraft which measures plasma moments with a time resolution of 31 ms. This high-time resolution allows us to make direct observations of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence below ion kinetic length scales. We present examples of the frequency spectra of the density, velocity, and thermal velocity. Our study reveals that although these parameters exhibit the same behavior at the magnetohydrodynamic scale, their spectra are remarkably different at the kinetic scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA12A..01L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA12A..01L"><span>Magnetosphere-Ionosphere-Thermosphere Response to Quasi-periodic Oscillations in <span class="hlt">Solar</span> <span class="hlt">Wind</span> Driving Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, J.; Wang, W.; Zhang, B.; Huang, C.</p> <p>2017-12-01</p> <p>Periodical oscillations with periods of several tens of minutes to several hours are commonly seen in the Alfven wave embedded in the <span class="hlt">solar</span> <span class="hlt">wind</span>. It is yet to be known how the <span class="hlt">solar</span> <span class="hlt">wind</span> oscillation frequency modulates the <span class="hlt">solar</span> <span class="hlt">wind</span>-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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> changes. This research highlights the critical role of IMF Bz oscillation frequency in constructing energy coupling function and understanding electrodynamic processes in the coupled <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere-ionosphere system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1610399W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1610399W"><span>Slow and fast <span class="hlt">solar</span> <span class="hlt">wind</span> - data selection and statistical analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wawrzaszek, Anna; Macek, Wiesław M.; Bruno, Roberto; Echim, Marius</p> <p>2014-05-01</p> <p>In this work we consider the important problem of selection of slow and fast <span class="hlt">solar</span> <span class="hlt">wind</span> data measured in-situ by the Ulysses spacecraft during two <span class="hlt">solar</span> minima (1995-1997, 2007-2008) and <span class="hlt">solar</span> maximum (1999-2001). To recognise different types of <span class="hlt">solar</span> <span class="hlt">wind</span> we use a set of following parameters: radial velocity, proton density, proton temperature, the distribution of charge states of oxygen ions, and compressibility of magnetic field. We present how this idea of the data selection works on Ulysses data. In the next step we consider the chosen intervals for fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span> and perform statistical analysis of the fluctuating magnetic field components. In particular, we check the possibility of identification of inertial range by considering the scale dependence of the third and fourth orders scaling exponents of structure function. We try to verify the size of inertial range depending on the heliographic latitudes, heliocentric distance and phase of the <span class="hlt">solar</span> cycle. Research supported by the European Community's Seventh Framework Programme (FP7/2007 - 2013) under grant agreement no 313038/STORM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/6517833','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/6517833"><span><span class="hlt">Wind</span> loading on <span class="hlt">solar</span> concentrators: some general considerations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Roschke, E. J.</p> <p></p> <p>A survey has been completed to examine the problems and complications arising from <span class="hlt">wind</span> loading on <span class="hlt">solar</span> concentrators. <span class="hlt">Wind</span> loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of <span class="hlt">solar</span> collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. <span class="hlt">Wind</span> characteristics are discussed from a general point of view; current methods for determining design <span class="hlt">wind</span> speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. <span class="hlt">Wind</span> tunnel testing is discussed, and environmental <span class="hlt">wind</span> tunnels are reviewed; recent results onmore » heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly. <span class="hlt">Wind</span> loads, i.e., forces and moments, are proportional to the square of the mean <span class="hlt">wind</span> velocity. Forces are proportional to the square of concentrator diameter, and moments are proportional to the cube of diameter. Thus, <span class="hlt">wind</span> loads have an important bearing on size selection from both cost and performance standpoints. It is concluded that sufficient information exists so that reasonably accurate predictions of <span class="hlt">wind</span> loading are possible for a given paraboloidal concentrator configuration, provided that reliable and relevant <span class="hlt">wind</span> conditions are specified. Such predictions will be useful to the design engineer and to the systems engineer as well. Information is lacking, however, on <span class="hlt">wind</span> effects in field arrays of paraboloidal concentrators. <span class="hlt">Wind</span> tunnel tests have been performed on model heliostat arrays, but there are important aerodynamic differences between heliostats and paraboloidal dishes.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750043159&hterms=Xx&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DXx','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750043159&hterms=Xx&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DXx"><span>Interplanetary gas. XX - Does the radial <span class="hlt">solar</span> <span class="hlt">wind</span> speed increase with latitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brandt, J. C.; Harrington, R. S.; Roosen, R. G.</p> <p>1975-01-01</p> <p>The astrometric technique used to derive <span class="hlt">solar</span> <span class="hlt">wind</span> speeds from ionic comet-tail orientations has been used to test the suggestion that the radial <span class="hlt">solar</span> <span class="hlt">wind</span> speed is higher near the <span class="hlt">solar</span> poles than near the equator. We find no evidence for the suggested latitude variation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003hst..prop10083C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003hst..prop10083C"><span>HST UV Images of Saturn's Aurora Coordinated with Cassini <span class="hlt">Solar</span> <span class="hlt">Wind</span> Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clarke, John</p> <p>2003-07-01</p> <p>A key measurement goal of the Cassini mission to Saturn is to obtain simultaneous <span class="hlt">solar</span> <span class="hlt">wind</span> and auroral imaging measurements in a campaign scheduled for Jan. 2004. Cassini will measure the <span class="hlt">solar</span> <span class="hlt">wind</span> approaching Saturn continuously from 9 Jan. - 6 Feb., but not closer to Saturn due to competing spacecraft orientation constraints. The only system capable of imaging Saturn's aurora in early 2004 will be HST. In this community DD proposal we request the minimum HST time needed to support the Cassini mission during the <span class="hlt">solar</span> <span class="hlt">wind</span> campaign with UV images of Saturn's aurora. Saturn's magnetosphere is intermediate between the "closed" Jovian case with large internal sources of plasma and the Earth's magnetosphere which is open to <span class="hlt">solar</span> <span class="hlt">wind</span> interactions. Saturn's aurora has been shown to exhibit large temporal variations in brightness and morphology from Voyager and HST observations. Changes of auroral emitted power exceeding one order of magnitude, dawn brightenings, and latitudinal motions of the main oval have all been observed. Lacking knowledge of <span class="hlt">solar</span> <span class="hlt">wind</span> conditions near Saturn, it has not been possible to determine its role in Saturn's auroral processes, nor the mechanisms controlling the auroral precipitation. During Cassini's upcoming approach to Saturn there will be a unique opportunity to answer these questions. We propose to image one complete rotation of Saturn to determine the corotational and longitudinal dependences of the auroral activity. We will then image the active sector of Saturn once every two days for a total coverage of 26 days during the Cassini campaign to measure the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. This is the minimum coverage needed to ensure observations of the aurora under <span class="hlt">solar</span> <span class="hlt">wind</span> pressure variations of more than a factor of two, based on the <span class="hlt">solar</span> <span class="hlt">wind</span> pressure variations measured by Voyager 2 near Saturn on the declining phase of <span class="hlt">solar</span> activity. The team of proposers has carried out a similar coordinated observing campaign of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770022104','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770022104"><span>Geomagnetic activity: Dependence on <span class="hlt">solar</span> <span class="hlt">wind</span> parameters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Svalgaard, L.</p> <p>1977-01-01</p> <p>Current ideas about the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the earth's magnetosphere are reviewed. The <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure as well as the influx of interplanetary magnetic field lines are both important for the generation of geomagnetic activity. The influence of the geometry of the situation as well as the variability of the interplanetary magnetic field are both found to be important factors. Semi-annual and universal time variations are discussed as well as the 22-year cycle in geomagnetic activity. All three are found to be explainable by the varying geometry of the interaction. Long term changes in geomagnetic activity are examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910040202&hterms=coal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcoal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910040202&hterms=coal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcoal"><span><span class="hlt">Solar</span> power. [comparison of costs to <span class="hlt">wind</span>, nuclear, coal, oil and gas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Walton, A. L.; Hall, Darwin C.</p> <p>1990-01-01</p> <p>This paper describes categories of <span class="hlt">solar</span> technologies and identifies those that are economic. It compares the private costs of power from <span class="hlt">solar</span>, <span class="hlt">wind</span>, nuclear, coal, oil, and gas generators. In the southern United States, the private costs of building and generating electricity from new <span class="hlt">solar</span> and <span class="hlt">wind</span> power plants are less than the private cost of electricity from a new nuclear power plant. <span class="hlt">Solar</span> power is more valuable than nuclear power since all <span class="hlt">solar</span> 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 <span class="hlt">wind</span> and nuclear power. Damage from air pollution, when factored into the cost of power from fossil fuels, alters the cost comparison in favor of <span class="hlt">solar</span> and <span class="hlt">wind</span> power. Some policies are more effective at encouraging alternative energy technologies that pollute less and improve national security.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021490&hterms=english+varieties&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Denglish%2Bvarieties','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021490&hterms=english+varieties&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Denglish%2Bvarieties"><span>The variety of MHD shock waves interactions in the <span class="hlt">solar</span> <span class="hlt">wind</span> flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grib, S. A.</p> <p>1995-01-01</p> <p>Different types of nonlinear shock wave interactions in some regions of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow are considered. It is shown, that the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> fast shock waves is also evaluated. The sketch of the classification of the MHD discontinuities interactions, connected with the <span class="hlt">solar</span> <span class="hlt">wind</span> evolution is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..278a2070J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..278a2070J"><span>Thermodynamic characteristics of a novel <span class="hlt">wind-solar</span>-liquid air energy storage system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ji, W.; Zhou, Y.; Sun, Y.; Zhang, W.; Pan, C. Z.; Wang, J. J.</p> <p>2017-12-01</p> <p>Due to the nature of fluctuation and intermittency, the utilization of <span class="hlt">wind</span> and <span class="hlt">solar</span> power will bring a huge impact to the power grid management. Therefore a novel hybrid <span class="hlt">wind-solar</span>-liquid air energy storage (WS-LAES) system was proposed. In this system, <span class="hlt">wind</span> and <span class="hlt">solar</span> power are stored in the form of liquid air by cryogenic liquefaction technology and thermal energy by <span class="hlt">solar</span> 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 <span class="hlt">wind</span> and <span class="hlt">solar</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.6000S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.6000S"><span>Interaction between <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Lunar Magnetic Anomalies observed by Kaguya MAP-PACE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Yoshifumi; Yokota, Shoichiro; Tanaka, Takaaki; Asamura, Kazushi; Nishino, Masaki; Yamamoto, Tadateru; Uemura, Kota; Tsunakawa, Hideo</p> <p>2010-05-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> from penetrating into the magnetosphere, <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> and the lunar magnetic anomalies. MAG/ER on Lunar Prospector found heating of the <span class="hlt">solar</span> <span class="hlt">wind</span> electrons presumably due to the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013323','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013323"><span>Multifluid Simulations of the Global <span class="hlt">Solar</span> <span class="hlt">Wind</span> Including Pickup Ions and Turbulence Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvyn L.; Usmanov, A. V.</p> <p>2011-01-01</p> <p>I will describe a three-dimensional magnetohydrodynamic model of the <span class="hlt">solar</span> <span class="hlt">wind</span> that takes into account turbulent heating of the <span class="hlt">wind</span> by velocity and magnetic fluctuations as well as a variety of effects produced by interstellar pickup protons. The interstellar pickup protons are treated in the model as one fluid and the protons and electrons are treated together as a second fluid. The model equations include a Reynolds decomposition of the plasma velocity and magnetic field into mean and fluctuating quantities, as well as energy transfer from interstellar pickup protons to <span class="hlt">solar</span> <span class="hlt">wind</span> protons that results in the deceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span>. The model is used to simulate the global steady-state structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the region from 0.3 to 100 AU. The simulation assumes that the background magnetic field on the Sun is either a dipole (aligned or tilted with respect to the <span class="hlt">solar</span> rotation axis) or one that is deduced from <span class="hlt">solar</span> magnetograms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.2745B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.2745B"><span>ULF Wave Activity in the Magnetosphere: Resolving <span class="hlt">Solar</span> <span class="hlt">Wind</span> Interdependencies to Identify Driving Mechanisms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bentley, S. N.; Watt, C. E. J.; Owens, M. J.; Rae, I. J.</p> <p>2018-04-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>. However, the interdependency of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters and the variety of <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling processes make it difficult to distinguish the effect of individual processes and to predict magnetospheric wave power using <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> parameters, accounting for their interdependencies. The most influential parameters for ground-based ULF wave power are <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> driving parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SoPh..293...47R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SoPh..293...47R"><span>The "FIP Effect" and the Origins of <span class="hlt">Solar</span> Energetic Particles and of the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reames, Donald V.</p> <p>2018-03-01</p> <p>We find that the element abundances in <span class="hlt">solar</span> energetic particles (SEPs) and in the slow <span class="hlt">solar</span> <span class="hlt">wind</span> (SSW), relative to those in the photosphere, show different patterns as a function of the first ionization potential (FIP) of the elements. Generally, the SEP and SSW abundances reflect abundance samples of the <span class="hlt">solar</span> corona, where low-FIP elements, ionized in the chromosphere, are more efficiently conveyed upward to the corona than high-FIP elements that are initially neutral atoms. Abundances of the elements, especially C, P, and S, show a crossover from low to high FIP at {≈} 10 eV in the SEPs but {≈} 14 eV for the <span class="hlt">solar</span> <span class="hlt">wind</span>. Naively, this seems to suggest cooler plasma from sunspots beneath active regions. More likely, if the ponderomotive force of Alfvén waves preferentially conveys low-FIP ions into the corona, the source plasma that eventually will be shock-accelerated as SEPs originates in magnetic structures where Alfvén waves resonate with the loop length on closed magnetic field lines. This concentrates FIP fractionation near the top of the chromosphere. Meanwhile, the source of the SSW may lie near the base of diverging open-field lines surrounding, but outside of, active regions, where such resonance does not exist, allowing fractionation throughout the chromosphere. We also find that energetic particles accelerated from the <span class="hlt">solar</span> <span class="hlt">wind</span> itself by shock waves at corotating interaction regions, generally beyond 1 AU, confirm the FIP pattern of the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040010591&hterms=use+solar+panels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Duse%2Bsolar%2Bpanels','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040010591&hterms=use+solar+panels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Duse%2Bsolar%2Bpanels"><span>Genesis <span class="hlt">Solar-Wind</span> Sample Return Mission: The Materials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jurewicz, A. J. G.; Burnett, D. S.; Wiens, R. C.; Woolum, D.</p> <p>2003-01-01</p> <p>The Genesis spacecraft has two primary instruments which passively collect <span class="hlt">solar</span> <span class="hlt">wind</span>. The first is the collector arrays , a set of panels, each of which can deploy separately to sample the different kinds of <span class="hlt">solar</span> <span class="hlt">wind</span> (regimes). The second is the concentrator, an electrostatic mirror which will concentrate ions of mass 4 through mass 25 by about a factor of 20 by focusing them onto a 6 cm diameter target. When not deployed, these instruments fit into a compact canister. After a two year exposure time, the deployed instruments can be folded up, sealed into the canister, and returned to earth for laboratory analysis. Both the collector arrays and the concentrator will contain suites of ultra-high purity target materials, each of which is tailored to enable the analysis of a different family of elements. This abstract is meant to give a brief overview of the Genesis mission, insight into what materials were chosen for flight and why, as well as head s up information as to what will be available to planetary scientist for analysis when the <span class="hlt">solar-wind</span> samples return to Earth in 2003. Earth. The elemental and isotopic abundances of the <span class="hlt">solar</span> <span class="hlt">wind</span> will be analyzed in state-of-the-art laboratories, and a portion of the sample will be archived for the use of future generations of planetary scientists. Technical information about the mission can be found at www.gps.caltech.edu/genesis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SSRv..214...56C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SSRv..214...56C"><span>Evolution of the Sunspot Number and <span class="hlt">Solar</span> <span class="hlt">Wind</span> B Time Series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cliver, Edward W.; Herbst, Konstantin</p> <p>2018-03-01</p> <p>The past two decades have witnessed significant changes in our knowledge of long-term <span class="hlt">solar</span> and <span class="hlt">solar</span> <span class="hlt">wind</span> activity. The sunspot number time series (1700-present) developed by Rudolf Wolf during the second half of the 19th century was revised and extended by the group sunspot number series (1610-1995) of Hoyt and Schatten during the 1990s. The group sunspot number is significantly lower than the Wolf series before ˜1885. An effort from 2011-2015 to understand and remove differences between these two series via a series of workshops had the unintended consequence of prompting several alternative constructions of the sunspot number. Thus it has been necessary to expand and extend the sunspot number reconciliation process. On the <span class="hlt">solar</span> <span class="hlt">wind</span> side, after a decade of controversy, an ISSI International Team used geomagnetic and sunspot data to obtain a high-confidence time series of the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field strength (B) from 1750-present that can be compared with two independent long-term (> ˜600 year) series of annual B-values based on cosmogenic nuclides. In this paper, we trace the twists and turns leading to our current understanding of long-term <span class="hlt">solar</span> and <span class="hlt">solar</span> <span class="hlt">wind</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ASSP...19..531B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ASSP...19..531B"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Monitoring with SWIM-SARA Onboard Chandrayaan-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>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.</p> <p></p> <p>The SARA experiment aboard the Indian lunar mission Chandrayaan-1 consists of two instruments: Chandrayaan-1 Energetic Neutral Analyzer (CENA) and the <span class="hlt">SolarWind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> ions. SWIM will monitor the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TESS....120001J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....120001J"><span>How Reliable Is the Prediction of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Background?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jian, Lan K.; MacNeice, Peter; Taktakishvili, Aleksandre; Odstrcil, Dusan; Jackson, Bernard; Yu, Hsiu-Shan; Riley, Pete; Sokolov, Igor</p> <p>2015-04-01</p> <p>The prediction of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760033224&hterms=methane+composition&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmethane%2Bcomposition','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760033224&hterms=methane+composition&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmethane%2Bcomposition"><span><span class="hlt">Solar-wind</span> interactions - Nature and composition of lunar atmosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mukherjee, N. R.</p> <p>1975-01-01</p> <p>The nature and composition of the lunar atmosphere are examined on the basis of <span class="hlt">solar-wind</span> interactions, and the nature of the species in the trapped-gas layer is discussed using results of theoretical and experimental investigations. It is shown that the moon has a highly tenuous atmosphere consisting of various species derived from five sources: <span class="hlt">solar-wind</span> interaction products, cosmic-ray interaction products, effects of meteoritic impacts, planetary degassing, and radioactive-decay products. Atmospheric concentrations are determined for those species derived from <span class="hlt">solar-wind</span> protons, alpha particles, and oxygen ions. Carbon chemistry is briefly discussed, and difficulties encountered in attempts to determine quantitatively the concentrations of molecular oxygen, atomic oxygen, carbon monoxide, carbon dioxide, and methane are noted. The calculated concentrations are shown to be in good agreement with observations by the Apollo 17 lunar-surface mass spectrometer and orbital UV spectrometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002079','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002079"><span>Spacecraft observations of the <span class="hlt">solar</span> <span class="hlt">wind</span> composition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bame, S. J.</p> <p>1972-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> composition studies by means of plasma analyzers carried on various spacecraft are reviewed. The average ratio of helium to hydrogen over the <span class="hlt">solar</span> cycle is close to 0.045; values as low as 0.0025 and as high as 0.25 have been observed. High values have been observed following <span class="hlt">solar</span> flares and interplanetary shock waves when the flare gas driving the shock arrives at the spacecraft. Ions of He-3(+2), O-16(+6), and O-16(+7) have been observed with Vela 3 electrostatic analyzers. Further measurements with Vela 5 analyzers have shown the presence of N-14(+6), Si-28(+7) to Si-28(+9) and Fe-56(+7) to Fe-56(+12) ions. The relative abundance of oxygen, silicon, and iron in the <span class="hlt">solar</span> <span class="hlt">wind</span> of July 6, 1969, was 1.00, 0.21, and 0.17, which is very similar to reported values for the corona. The ratio of helium to oxygen is variable; the average value of He/O is close to 100, but values between 30 and 400 have been observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASS...34..237K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASS...34..237K"><span>Characteristics and Geoeffectiveness of Small-scale Magnetic Flux Ropes in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Myeong Joon; Park, Kyung Sun; Lee, Dae-Young; Choi, Cheong-Rim; Kim, Rok Soon; Cho, Kyungsuk; Choi, Kyu-Cheol; Kim, Jaehun</p> <p>2017-12-01</p> <p>Magnetic flux ropes, often observed during intervals of interplanetary coronal mass ejections, have long been recognized to be critical in space weather. In this work, we focus on magnetic flux rope structure but on a much smaller scale, and not necessarily related to interplanetary coronal mass ejections. Using near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> advanced composition explorer (<span class="hlt">ACE</span>) observations from 1998 to 2016, we identified a total of 309 small-scale magnetic flux ropes (SMFRs). We compared the characteristics of identified SMFR events with those of normal magnetic cloud (MC) events available from the existing literature. First, most of the MCs and SMFRs have similar values of accompanying <span class="hlt">solar</span> <span class="hlt">wind</span> speed and proton densities. However, the average magnetic field intensity of SMFRs is weaker ( 7.4 nT) than that of MCs ( 10.6 nT). Also, the average duration time and expansion speed of SMFRs are 2.5 hr and 2.6 km/s, respectively, both of which are smaller by a factor of 10 than those of MCs. In addition, we examined the geoeffectiveness of SMFR events by checking their correlation with magnetic storms and substorms. Based on the criteria Sym-H < -50 nT (for identification of storm occurrence) and AL < -200 nT (for identification of substorm occurrence), we found that for 88 SMFR events (corresponding to 28.5 % of the total SMFR events), substorms occurred after the impact of SMFRs, implying a possible triggering of substorms by SMFRs. In contrast, we found only two SMFRs that triggered storms. We emphasize that, based on a much larger database than used in previous studies, all these previously known features are now firmly confirmed by the current work. Accordingly, the results emphasize the significance of SMFRs from the viewpoint of possible triggering of substorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850041177&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231055','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850041177&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231055"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> control of magnetospheric pressure (CDAW 6)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairfield, D. H.</p> <p>1985-01-01</p> <p>The CDAW 6 data base is used to compare <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetospheric pressures. The flaring angle of the tail magnetopause is determined by assuming that the component of <span class="hlt">solar</span> <span class="hlt">wind</span> pressure normal to the tail boundary is equal to the total pressure within the tail. Results indicate an increase in the tail flaring angle from 18 deg to 32 deg prior to the 1055 substorm onset and a decrease to 25 deg after the onset. This behavior supports the concept of tail energy storage before the substorm and subsequent release after the onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010038050','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010038050"><span>Fluid Aspects of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Disturbances Driven by Coronal Mass Ejections. Appendix 3</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gosling, J. T.; Riley, Pete</p> <p>2001-01-01</p> <p>Transient disturbances in the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. Our purpose here is to provide a brief tutorial on fluid aspects of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> using a simple one-dimensional, adiabatic (except at shocks), gas dynamic code. The simulations begin outside the critical point where the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> material and the ambient <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29151613','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29151613"><span>Heavy noble gases in <span class="hlt">solar</span> <span class="hlt">wind</span> delivered by Genesis mission.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meshik, Alex; Hohenberg, Charles; Pravdivtseva, Olga; Burnett, Donald</p> <p>2014-02-15</p> <p>One of the major goals of the Genesis Mission was to refine our knowledge of the isotopic composition of the heavy noble gases in <span class="hlt">solar</span> <span class="hlt">wind</span> and, by inference, the Sun, which represents the initial composition of the <span class="hlt">solar</span> system. This has now been achieved with permil precision: 36 Ar/ 38 Ar = 5.5005 ± 0.0040, 86 Kr/ 84 Kr = .3012 ± .0004, 83 Kr/ 84 Kr = .2034 ± .0002, 82 Kr/ 84 Kr = .2054 ± .0002, 80 Kr/ 84 Kr = .0412 ± .0002, 78 Kr/ 84 Kr = .00642 ± .00005, 136 Xe/ 132 Xe = .3001 ± .0006, 134 Xe/ 132 Xe = .3691 ± .0007, 131 Xe/ 132 Xe = .8256 ± .0012, 130 Xe/ 132 Xe = .1650 ± .0004, 129 Xe/ 132 Xe = 1.0405 ± .0010, 128 Xe/ 132 Xe = .0842 ± .0003, 126 Xe/ 132 Xe = .00416 ± .00009, and 124 Xe/ 132 Xe = .00491 ± .00007 (error-weighted averages of all published data). The Kr and Xe ratios measured in the Genesis <span class="hlt">solar</span> <span class="hlt">wind</span> collectors generally agree with the less precise values obtained from lunar soils and breccias, which have accumulated <span class="hlt">solar</span> <span class="hlt">wind</span> over hundreds of millions of years, suggesting little if any temporal variability of the isotopic composition of <span class="hlt">solar</span> <span class="hlt">wind</span> krypton and xenon. The higher precision for the initial composition of the heavy noble gases in the <span class="hlt">solar</span> system allows (1) to confirm that, exept 136 Xe and 134 Xe, the mathematically derived U-Xe is equivalent to <span class="hlt">Solar</span> <span class="hlt">Wind</span> Xe and (2) to provide an opportunity for better understanding the relationship between the starting composition and Xe-Q (and Q-Kr), the dominant current "planetary" component, and its host, the mysterious phase-Q.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5688518','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5688518"><span>Heavy noble gases in <span class="hlt">solar</span> <span class="hlt">wind</span> delivered by Genesis mission</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meshik, Alex; Hohenberg, Charles; Pravdivtseva, Olga; Burnett, Donald</p> <p>2017-01-01</p> <p>One of the major goals of the Genesis Mission was to refine our knowledge of the isotopic composition of the heavy noble gases in <span class="hlt">solar</span> <span class="hlt">wind</span> and, by inference, the Sun, which represents the initial composition of the <span class="hlt">solar</span> system. This has now been achieved with permil precision: 36Ar/38Ar = 5.5005 ± 0.0040, 86Kr/84Kr = .3012 ± .0004, 83Kr/84Kr = .2034 ± .0002, 82Kr/84Kr = .2054 ± .0002, 80Kr/84Kr = .0412 ± .0002, 78Kr/84Kr = .00642 ± .00005, 136Xe/132Xe = .3001 ± .0006, 134Xe/132Xe = .3691 ± .0007, 131Xe/132Xe = .8256 ± .0012, 130Xe/132Xe = .1650 ± .0004, 129Xe/132Xe = 1.0405 ± .0010, 128Xe/132Xe = .0842 ± .0003, 126Xe/132Xe = .00416 ± .00009, and 124Xe/132Xe = .00491 ± .00007 (error-weighted averages of all published data). The Kr and Xe ratios measured in the Genesis <span class="hlt">solar</span> <span class="hlt">wind</span> collectors generally agree with the less precise values obtained from lunar soils and breccias, which have accumulated <span class="hlt">solar</span> <span class="hlt">wind</span> over hundreds of millions of years, suggesting little if any temporal variability of the isotopic composition of <span class="hlt">solar</span> <span class="hlt">wind</span> krypton and xenon. The higher precision for the initial composition of the heavy noble gases in the <span class="hlt">solar</span> system allows (1) to confirm that, exept 136Xe and 134Xe, the mathematically derived U–Xe is equivalent to <span class="hlt">Solar</span> <span class="hlt">Wind</span> Xe and (2) to provide an opportunity for better understanding the relationship between the starting composition and Xe-Q (and Q-Kr), the dominant current “planetary” component, and its host, the mysterious phase-Q. PMID:29151613</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170002772&hterms=electrons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Delectrons','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170002772&hterms=electrons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Delectrons"><span>On Electron-Scale Whistler Turbulence in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Narita, Y.; Nakamura, R.; Baumjohann, W.; Glassmeier, K.-H.; Motschmann, U.; Giles, B.; Magnes, W.; Fischer, D.; Torbert, R. B.; Russell, C. T.</p> <p>2016-01-01</p> <p>For the first time, the dispersion relation for turbulence magnetic field fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> is determined directly on small scales of the order of the electron inertial length, using four-point magnetometer observations from the Magnetospheric Multiscale mission. The data are analyzed using the high-resolution adaptive wave telescope technique. Small-scale <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence is primarily composed of highly obliquely propagating waves, with dispersion consistent with that of the whistler mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1913260S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1913260S"><span>On the properties of energy transfer in <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sorriso-Valvo, Luca; Marino, Raffaele; Chen, Christopher H. K.; Wicks, Robert; Nigro, Giuseppina</p> <p>2017-04-01</p> <p>Spacecraft observations have shown that the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma is heated during its expansion in the heliosphere. The necessary energy is made available at small scales by a turbulent cascade, although the nature of the heating processes is still debated. Because of the intermittent nature of turbulence, the small-scale energy is inhomogeneously distributed in space, resulting for example in the formation of highly localized current sheets and eddies. In order to understand the small-scale plasma processes occurring in the <span class="hlt">solar</span> <span class="hlt">wind</span>, the global and local properties of such energy distribution must be known. Here we study such properties using a proxy derived from the Von Karman-Howart relation for magnetohydrodynamics. The statistical properties of the energy transfer rate in the fluid range of scales are studied in detail using <span class="hlt">WIND</span> spacecraft plasma and magnetic field measurements and discussed in the framework of the multifractal turbulent cascade. Dependence of the energy dissipation proxy on the <span class="hlt">solar</span> <span class="hlt">wind</span> conditions (speed, type, <span class="hlt">solar</span> activity...) is analysed, and its evolution during <span class="hlt">solar</span> <span class="hlt">wind</span> expansion in the heliosphere is described using Helios II and Ulysses measurements. A comparison with other proxies, such as the PVI, is performed. Finally, the local singularity properties of the energy dissipation proxy are conditionally compared to the corresponding particle velocity distributions. This allows the identification of specific plasma features occurring near turbulent dissipation events, and could be used as enhanced mode trigger in future space missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhDT.........6F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhDT.........6F"><span>A Study of Fermi Acceleration of Suprathermal <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Freeman, Theodore James</p> <p></p> <p>The <span class="hlt">Wind</span> spacecraft has observed numerous sunward bursts of ~2 MeV ions upstream of the Earth's bow shock. The bursts typically last several minutes at the highest energies, but they can last for tens of minutes at intermediate energies (tens to hundreds of keV). The MeV ions are not protons or alpha particles, and are probably oxygen ions. There are two possible sources of these particles: Fermi acceleration of <span class="hlt">solar</span> <span class="hlt">wind</span> ions, and ring current particles which have escaped from the Earth's magnetosphere. In this dissertation, <span class="hlt">Wind</span> observations and numerical particle simulations of Fermi acceleration are presented which demonstrate that suprathermal <span class="hlt">solar</span> <span class="hlt">wind</span> O6+ ions are the most likely source of these bursts. Since the Fermi mechanism accelerates all ions to approximately the same ratio of energy to charge, H+ and He2+ ions are accelerated to much lower energies than O6+ ions. In this model, suprathermal ions are reflected between the bow shock and rotations in the interplanetary magnetic field (IMF) upstream of the shock, gaining energy due to the relative motion of the reflecting magnetic structures. Each burst either coincides with or is closely followed by a large IMF rotation. By using measured magnetic field data, the timing of the bursts detected by <span class="hlt">Wind</span> is precisely reproduced in the simulation. The energy spectra observed by <span class="hlt">Wind</span> are also reproduced by adding H+ , He2+ , and O6+ fluxes together, and assuming that there is an increase of ~2 orders of magnitude in the high energy tail of the <span class="hlt">solar</span> <span class="hlt">wind</span> oxygen distribution. An enhancement of this order of magnitude in CNO group ions was measured by the ion composition experiment on <span class="hlt">Wind</span> in association with these bursts. An examination of the magnetospheric escape model shows that while escaping O+ ions can account for some features of the data, such as the longer bursts of intermediate energy ions, it cannot account for the short duration ~2 MeV bursts themselves, because O+ ions scatter diffusively in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1221389-depth-profiling-analysis-solar-wind-helium-collected-diamond-like-carbon-film-from-genesis','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1221389-depth-profiling-analysis-solar-wind-helium-collected-diamond-like-carbon-film-from-genesis"><span>Depth profiling analysis of <span class="hlt">solar</span> <span class="hlt">wind</span> helium collected in diamond-like carbon film from Genesis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; ...</p> <p>2015-01-01</p> <p>The distribution of <span class="hlt">solar-wind</span> ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the <span class="hlt">solar</span> <span class="hlt">wind</span>. Thus, they provide an experimental basis for revealing ancient <span class="hlt">solar</span> activities represented by <span class="hlt">solar-wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the <span class="hlt">solar</span> <span class="hlt">wind</span> ⁴He depth profile ismore » consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all <span class="hlt">solar-wind</span> elements heavier than H are completely intact in this Genesis collector and, consequently, the <span class="hlt">solar</span> particle energy distributions for each element can be calculated from their depth profiles. Ancient <span class="hlt">solar</span> activities and space weathering of <span class="hlt">solar</span> system objects could be quantitatively reproduced by <span class="hlt">solar</span> particle implantation profiles.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM31A2615K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM31A2615K"><span>Dependence of Substorm Evolution on <span class="hlt">Solar</span> <span class="hlt">Wind</span> Condition: Simulation Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamiyoshikawa, N.; Ebihara, Y.; Tanaka, T.</p> <p>2017-12-01</p> <p>A substorm is one of the remarkable disturbances occurring in the magnetosphere. It is known that the substorm occurs frequently when IMF is southward and <span class="hlt">solar</span> <span class="hlt">wind</span> speed is high. However, the physical process to determine substorm scale is not well understood. We reproduced substorms by using global MHD simulation, calculated auroral electrojet (ionospheric Hall current) flowing in the ionosphere to investigate the dependence of substorm evolution on <span class="hlt">solar</span> <span class="hlt">wind</span> condition. <span class="hlt">Solar</span> <span class="hlt">wind</span> speed of 372.4 km/s and IMF Bz of 5.0 nT were imposed to, obtain the quasi-stationary state of the magnetosphere. Then the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters were changed as a step function. For the <span class="hlt">solar</span> <span class="hlt">wind</span> speed, we assumed 300 km/s, 500 km/s and 700 km/s. For IMF, we assumed -1.0 nT, -3.0 nT, -5.0 nT, -7.0 nT and -9.0 nT. In total, 15 simulation runs were performed. In order to objectively evaluate the substorm, the onset was identified with the method based on the one proposed by Newell et al. (2011). This method uses the SME index that is an extension of the AE index. In this study, the geomagnetic variation induced by the ionospheric Hall current was obtained every 1 degree from the magnetic latitude 40 degrees to 80 degrees and in every 0.5 hours in the magnetic region direction. The upper and the lower envelopes of the geomagnetic variation are regarded as SMU index and SML index, respectively. The larger the <span class="hlt">solar</span> <span class="hlt">wind</span> speed, the larger the southward IMF, the more the onset tends to be faster. This tendency is consistent with the onset occurrence probability indicated by Newell et al. (2016). Moreover, the minimum value of the SML index within 30 minutes from the beginning of the onset tends to decrease with the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and the magnitude of the southward IMF. A rapid decrease of the SML index can be explained by a rapid increase in the field-aligned currents flowing in and out of the nightside ionosphere. This means that electromagnetic energies flowing into the ionosphere</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981IJAmE...2..223B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981IJAmE...2..223B"><span>Potential for a Danish power system using <span class="hlt">wind</span> energy generators, <span class="hlt">solar</span> cells and storage</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blegaa, S.; Christiansen, G.</p> <p>1981-10-01</p> <p>Performance characteristics of a combined <span class="hlt">solar/wind</span> 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 <span class="hlt">wind/solar</span> installations is presented, assuming 12% efficiency for the <span class="hlt">solar</span> cells and various power coefficients of the windmills, in addition to long and short-term storage. Noting that no correlation between <span class="hlt">wind</span> and <span class="hlt">solar</span> energy availability was found, and a constant ratio of 60% <span class="hlt">wind</span>/40% <span class="hlt">solar</span> 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 <span class="hlt">solar/wind</span> systems, and 100% may be possible with the addition of pumped hydroelectric storage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010RScI...81k1301J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010RScI...81k1301J"><span>Invited Article: Electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail: Toward test missions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Janhunen, P.; Toivanen, P. K.; Polkko, J.; Merikallio, S.; Salminen, P.; Haeggström, E.; Seppänen, H.; Kurppa, R.; Ukkonen, J.; Kiprich, S.; Thornell, G.; Kratz, H.; Richter, L.; Krömer, O.; Rosta, R.; Noorma, M.; Envall, J.; Lätt, S.; Mengali, G.; Quarta, A. A.; Koivisto, H.; Tarvainen, O.; Kalvas, T.; Kauppinen, J.; Nuottajärvi, A.; Obraztsov, A.</p> <p>2010-11-01</p> <p>The electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail (E-sail) is a space propulsion concept that uses the natural <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the <span class="hlt">solar</span> <span class="hlt">wind</span> is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the <span class="hlt">solar</span> system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21133454','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21133454"><span>Invited article: Electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail: toward test missions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Janhunen, P; Toivanen, P K; Polkko, J; Merikallio, S; Salminen, P; Haeggström, E; Seppänen, H; Kurppa, R; Ukkonen, J; Kiprich, S; Thornell, G; Kratz, H; Richter, L; Krömer, O; Rosta, R; Noorma, M; Envall, J; Lätt, S; Mengali, G; Quarta, A A; Koivisto, H; Tarvainen, O; Kalvas, T; Kauppinen, J; Nuottajärvi, A; Obraztsov, A</p> <p>2010-11-01</p> <p>The electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail (E-sail) is a space propulsion concept that uses the natural <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the <span class="hlt">solar</span> <span class="hlt">wind</span> is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the <span class="hlt">solar</span> system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010093223','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010093223"><span>A Study of the Structure of the Source Region of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> in Support of a <span class="hlt">Solar</span> Probe Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Habbal, Shadia R.; Forman, M. A. (Technical Monitor)</p> <p>2001-01-01</p> <p>Despite the richness of the information about the physical properties and the structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> provided by the Ulysses and SOHO (<span class="hlt">Solar</span> and Heliospheric Observatory) observations, fundamental questions regarding the nature of the coronal heating mechanisms, their source, and the manifestations of the fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span>, still remain unanswered. The last unexplored frontier to establish the connection between the structure and dynamics of the <span class="hlt">solar</span> atmosphere, its extension into interplanetary space, and the mechanisms responsible for the evolution of the <span class="hlt">solar</span> <span class="hlt">wind</span>, is the corona between 1 and 30 R(sub s). A <span class="hlt">Solar</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. In support of this mission, we fulfilled the following two long-term projects: (1) Study of the evolution of waves and turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> (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 <span class="hlt">Solar</span> <span class="hlt">Wind</span> 9 International Conference which was held in October 1998. A brief report on the conference is also described in what follows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19980236879&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dwind%2Bmonitor','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19980236879&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dwind%2Bmonitor"><span>Comparisons of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Coupling Parameters with Auroral Energy Deposition Rates</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elsen, R.; Brittnacher, M. J.; Fillingim, M. O.; Parks, G. K.; Germany G. A.; Spann, J. F., Jr.</p> <p>1997-01-01</p> <p>Measurement of the global rate of energy deposition in the ionosphere via auroral particle precipitation is one of the primary goals of the Polar UVI program and is an important component of the ISTP program. The instantaneous rate of energy deposition for the entire month of January 1997 has been calculated by applying models to the UVI images and is presented by Fillingim et al. In this session. A number of parameters that predict the rate of coupling of <span class="hlt">solar</span> <span class="hlt">wind</span> energy into the magnetosphere have been proposed in the last few decades. Some of these parameters, such as the epsilon parameter of Perrault and Akasofu, depend on the instantaneous values in the <span class="hlt">solar</span> <span class="hlt">wind</span>. Other parameters depend on the integrated values of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters, especially IMF Bz, e.g. applied flux which predicts the net transfer of magnetic flux to the tail. While these parameters have often been used successfully with substorm studies, their validity in terms of global energy input has not yet been ascertained, largely because data such as that supplied by the ISTP program was lacking. We have calculated these and other energy coupling parameters for January 1997 using <span class="hlt">solar</span> <span class="hlt">wind</span> data provided by <span class="hlt">WIND</span> and other <span class="hlt">solar</span> <span class="hlt">wind</span> monitors. The rates of energy input predicted by these parameters are compared to those measured through UVI data and correlations are sought. Whether these parameters are better at providing an instantaneous rate of energy input or an average input over some time period is addressed. We also study if either type of parameter may provide better correlations if a time delay is introduced; if so, this time delay may provide a characteristic time for energy transport in the coupled <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere-ionosphere system.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980210218','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980210218"><span>Mapping the <span class="hlt">Solar</span> <span class="hlt">Wind</span> from its Source Region into the Outer Corona</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esser, Ruth</p> <p>1998-01-01</p> <p>Knowledge of the radial variation of the plasma conditions in the coronal source region of the <span class="hlt">solar</span> <span class="hlt">wind</span> is essential to exploring coronal heating and <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750053168&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DWind%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750053168&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DWind%2Benergy"><span>Summary of NASA-Lewis Research Center <span class="hlt">solar</span> heating and cooling and <span class="hlt">wind</span> energy programs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vernon, R. W.</p> <p>1975-01-01</p> <p>NASA is planning to construct and operate a <span class="hlt">solar</span> heating and cooling system in conjunction with a new office building being constructed at Langley Research Center. The technology support for this project will be provided by a <span class="hlt">solar</span> energy program underway at NASA's Lewis Research Center. The <span class="hlt">solar</span> program at Lewis includes: testing of <span class="hlt">solar</span> collectors with a <span class="hlt">solar</span> simulator, outdoor testing of collectors, property measurements of selective and nonselective coatings for <span class="hlt">solar</span> collectors, and a <span class="hlt">solar</span> model-systems test loop. NASA-Lewis has been assisting the National Science Foundation and now the Energy Research and Development Administration in planning and executing a national <span class="hlt">wind</span> energy program. The areas of the <span class="hlt">wind</span> energy program that are being conducted by Lewis include: design and operation of a 100 kW experimental <span class="hlt">wind</span> generator, industry-designed and user-operated <span class="hlt">wind</span> generators in the range of 50 to 3000 kW, and supporting research and technology for large <span class="hlt">wind</span> energy systems. An overview of these activities is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120015694&hterms=protons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dprotons','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120015694&hterms=protons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dprotons"><span>Three-Dimensional Magnetohydrodynamic Modeling of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Including Pickup Protons and Turbulence Transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.</p> <p>2012-01-01</p> <p>To study the effects of interstellar pickup protons and turbulence on the structure and dynamics of the <span class="hlt">solar</span> <span class="hlt">wind</span>, we have developed a fully three-dimensional magnetohydrodynamic <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> protons, energy transfer from pickup protons to <span class="hlt">solar</span> <span class="hlt">wind</span> protons, and plasma heating by turbulent dissipation. Separate mass and energy equations are used for the <span class="hlt">solar</span> <span class="hlt">wind</span> and pickup protons, though a single momentum equation is employed under the assumption that the pickup protons are comoving with the <span class="hlt">solar</span> <span class="hlt">wind</span> protons.We compute the global structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM34A..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM34A..01H"><span>Kinetic Interactions Between the <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Lunar Magnetic Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Halekas, J. S.; Poppe, A. R.; Fatemi, S.; Turner, D. L.; Holmstrom, M.</p> <p>2016-12-01</p> <p>Despite their relatively weak strength, small scale, and incoherence, lunar magnetic anomalies can affect the incoming <span class="hlt">solar</span> <span class="hlt">wind</span> flow. The plasma interaction with lunar magnetic fields drives significant compressions of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and magnetic field, deflections of the incoming flow, and a host of plasma waves ranging from the ULF to the electrostatic range. Recent work suggests that the large-scale features of the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetic anomaly interactions may be driven by ion-ion instabilities excited by reflected ions, raising the possibility that they are analogous to ion foreshock phenomena. Indeed, despite their small scale, many of the phenomena observed near lunar magnetic anomalies appear to have analogues in the foreshock regions of terrestrial planets. We discuss the charged particle distributions, fields, and waves observed near lunar magnetic anomalies, and place them in a context with the foreshocks of the Earth, Mars, and other <span class="hlt">solar</span> system objects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21568542','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21568542"><span>Systematic measurements of ion-proton differential streaming in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Berger, L; Wimmer-Schweingruber, R F; Gloeckler, G</p> <p>2011-04-15</p> <p>The small amount of heavy ions in the highly rarefied <span class="hlt">solar</span> <span class="hlt">wind</span> are sensitive tracers for plasma-physics processes, which are usually not accessible in the laboratory. We have analyzed differential streaming between heavy ions and protons in the <span class="hlt">solar</span> <span class="hlt">wind</span> at 1 AU. 3D velocity vector and magnetic field measurements from the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electron Proton Alpha Monitor and the Magnetometer aboard the Advanced Composition Explorer were used to reconstruct the ion-proton difference vector v(ip) = v(i) - v(p) from the 12 min 1D <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer observations. We find that all 44 analyzed heavy ions flow along the interplanetary magnetic field at velocities which are smaller than, but comparable to, the local Alfvén speed C(A). The flow speeds of 35 of the 44 ion species lie within the range of ±0.15C(A) around 0.55C(A), the flow speed of He(2+).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22654173-contribution-coronal-jets-solar-wind','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22654173-contribution-coronal-jets-solar-wind"><span>THE CONTRIBUTION OF CORONAL JETS TO THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lionello, R.; Török, T.; Titov, V. S.</p> <p></p> <p>Transient collimated plasma eruptions in the <span class="hlt">solar</span> corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of <span class="hlt">solar</span> activity. It has been suggested that these events contribute to the mass and energy content of the corona and <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. We emphasize, however, that more advanced observations and simulations (including parametric studies) are needed to substantiate this conjecture.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900063359&hterms=heinemann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dheinemann','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900063359&hterms=heinemann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dheinemann"><span>On WKB expansions for Alfven waves in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hollweg, Joseph V.</p> <p>1990-01-01</p> <p>The WKB expansion for 'toroidal' Alfven waves in <span class="hlt">solar</span> <span class="hlt">wind</span>, which is described by equations of Heinemann and Olbert (1980), is examined. In this case, the multiple scales method (Nayfeh, 1981) is used to obtain a uniform expansion. It is shown that the WKB expansion used by Belcher (1971) and Hollweg (1973) for Alfven waves in the <span class="hlt">solar</span> <span class="hlt">wind</span> is nonuniformly convergent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JGR....9514873H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JGR....9514873H"><span>On WKB expansions for Alfven waves in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hollweg, Joseph V.</p> <p>1990-09-01</p> <p>The WKB expansion for 'toroidal' Alfven waves in <span class="hlt">solar</span> <span class="hlt">wind</span>, which is described by equations of Heinemann and Olbert (1980), is examined. In this case, the multiple scales method (Nayfeh, 1981) is used to obtain a uniform expansion. It is shown that the WKB expansion used by Belcher (1971) and Hollweg (1973) for Alfven waves in the <span class="hlt">solar</span> <span class="hlt">wind</span> is nonuniformly convergent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSH21A2165L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSH21A2165L"><span>New Estimates of Inferred Ionic Charge States for <span class="hlt">Solar</span> Energetic Particle Events with <span class="hlt">ACE</span> and STEREO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Labrador, A. W.; Sollitt, L. S.; Cohen, C. M.; Cummings, A. C.; Leske, R. A.; Mason, G. M.; Mewaldt, R. A.; Stone, E.; von Rosenvinge, T. T.; Wiedenbeck, M. E.</p> <p>2012-12-01</p> <p><span class="hlt">Solar</span> energetic particle (SEP) mean ionic charge states can depend on source temperatures and populations (e.g. seed populations) and conditions during acceleration and transport such as stripping. Multi-spacecraft observations of charge states from widely separated spacecraft may reveal evidence for seed populations that vary with longitude. In this presentation, we report new estimates of inferred high energy ionic charge states using the Sollitt et al. (2008) method that fits SEP energy-dependent decay times for SEP event elements to derive mean charge states. In the method, intensity decay times during SEP events are fitted for each element for various energies, and then the energy dependence of the decay times is fitted for each element. Finally, charge-to-mass ratios relative to that of a calibration element (carbon in this case) are obtained, and when Q(C)=5.9 is assumed for calibration, mean charge states for other elements can be inferred. Previously, <span class="hlt">ACE</span>/SIS and <span class="hlt">ACE</span>/ULEIS data were applied to three SEP events (Nov. 6, 1997; Nov. 4, 2001; Apr. 21, 2002) with this method, and last year, we reported new results for the Dec. 6, 2006 SEP event compatible with SAMPEX/MAST results. Additional work continues to generalize and extend the software to use publicly available online data from <span class="hlt">ACE</span> and the two STEREO spacecraft. Energy ranges are those covered by the instruments on <span class="hlt">ACE</span> (e.g. reference element C at <.1 MeV/nuc from ULEIS to ~64 MeV/nuc from SIS) and on STEREO (e.g. C at 3.2 - 33 MeV/nuc from LET). Initial candidate SEP events for multi-spacecraft charge state estimates are those of Mar. 8, 2011, Mar. 21, 2011, Jan. 24, 2012, and Mar. 4, 2012. Results from events observed by single spacecraft may also be reported.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890058245&hterms=alicia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dalicia%2Bd','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890058245&hterms=alicia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dalicia%2Bd"><span><span class="hlt">Solar</span> <span class="hlt">wind</span>-magnetosphere coupling during intense magnetic storms (1978-1979)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gonzalez, Walter D.; Gonzalez, Alicia L. C.; Tsurutani, Bruce T.; Smith, Edward J.; Tang, Frances</p> <p>1989-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling problem during intense magnetic storms was investigated for ten intense magnetic storm events occurring between August 16, 1978 to December 28, 1979. Particular attention was given to the dependence of the ring current energization on the ISEE-measured <span class="hlt">solar-wind</span> parameters and the evolution of the ring current during the main phase of the intense storms. Several coupling functions were tested as energy input, and several sets of the ring current decay time-constant were searched for the best correlation with the Dst response. Results indicate that a large-scale magnetopause reconnection operates during an intense storm event and that the <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure plays an important role in the energization of the ring current.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996ESASP.392..277W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996ESASP.392..277W"><span>A Study of the <span class="hlt">Solar</span> <span class="hlt">Wind</span>-Magnetosphere Coupling Using Neural Networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Jian-Guo; Lundstedt, Henrik</p> <p>1996-12-01</p> <p>The interaction between <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling by predicting geomagnetic storms (as measured by the Dstindex) from <span class="hlt">solar</span> <span class="hlt">wind</span> measurements. The <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span> parameters (including various combinations of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling functions and the corresponding prediction results. Interesting Links: Lund Space Weather and AI</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996ApJ...462..982O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996ApJ...462..982O"><span>Thermally Driven One-Fluid Electron-Proton <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Eight-Moment Approximation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olsen, Espen Lyngdal; Leer, Egil</p> <p>1996-05-01</p> <p>In an effort to improve the "classical" <span class="hlt">solar</span> <span class="hlt">wind</span> model, we study an eight-moment approximation hydrodynamic <span class="hlt">solar</span> <span class="hlt">wind</span> model, in which the full conservation equation for the heat conductive flux is solved together with the conservation equations for mass, momentum, and energy. We consider two different cases: In one model the energy flux needed to drive the <span class="hlt">solar</span> <span class="hlt">wind</span> is supplied as heat flux from a hot coronal base, where both the density and temperature are specified. In the other model, the corona is heated. In that model, the coronal base density and temperature are also specified, but the temperature increases outward from the coronal base due to a specified energy flux that is dissipated in the corona. The eight-moment approximation solutions are compared with the results from a "classical" <span class="hlt">solar</span> <span class="hlt">wind</span> model in which the collision-dominated gas expression for the heat conductive flux is used. It is shown that the "classical" expression for the heat conductive flux is generally not valid in the <span class="hlt">solar</span> <span class="hlt">wind</span>. In collisionless regions of the flow, the eight-moment approximation gives a larger thermalization of the heat conductive flux than the models using the collision-dominated gas approximation for the heat flux, but the heat flux is still larger than the "saturation heat flux." This leads to a breakdown of the electron distribution function, which turns negative in the collisionless region of the flow. By increasing the interaction between the electrons, the heat flux is reduced, and a reasonable shape is obtained on the distribution function. By solving the full set of equations consistent with the eight-moment distribution function for the electrons, we are thus able to draw inferences about the validity of the eight-moment description of the <span class="hlt">solar</span> <span class="hlt">wind</span> as well as the validity of the very commonly used collision-dominated gas approximation for the heat conductive flux in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060051794&hterms=solar+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bradiation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060051794&hterms=solar+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bradiation"><span>Molecular Substrate Alteration by <span class="hlt">Solar</span> <span class="hlt">Wind</span> Radiation Documented on Flown Genesis Mission Array Materials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Calaway, Michael J.; Stansbery, Eileen K.</p> <p>2006-01-01</p> <p>The Genesis spacecraft sampling arrays were exposed to various regimes of <span class="hlt">solar</span> <span class="hlt">wind</span> during flight that included: 313.01 days of high-speed <span class="hlt">wind</span> from coronal holes, 335.19 days of low-speed inter-stream <span class="hlt">wind</span>, 191.79 days of coronal mass ejections, and 852.83 days of bulk <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> radiation molecular damage zone depth below the SiO2 native oxide layer ranging from 392 to 613 . This bulk <span class="hlt">solar</span> <span class="hlt">wind</span> radiation penetration depth is comparable to the depth of <span class="hlt">solar</span> <span class="hlt">wind</span> implantation depth of Mg measured by SIMS and SARISA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSH51B2227S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSH51B2227S"><span>Nature of Kinetic Scale Fluctuations in <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salem, C. S.; Chen, C. H.; Sundkvist, D. J.; Chaston, C. C.; Bale, S. D.; Mozer, F.</p> <p>2012-12-01</p> <p>We present an investigation of the nature of small-scale turbulent fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The nature of the dissipation range fluctuations of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence remains a major open question in heliospheric physics. The steepening of the observed (magnetic field) spectra at ion scales was originally attributed to ion cyclotron damping, but it was later suggested that it could well be due to the dispersive nature of fluctuations at these scales. The nature of the dispersive cascade at and below the ion scales is still debated, two leading hypothesis being that these fluctuations have characteristics of Kinetic Alfven Waves (KAW) or whistler waves. Other possible contributions from current sheets and/or kinetic instabilities have been suggested. There is mounting evidence that the fluctuations at these scales are KAW-like. In this study, we analyze several carefully selected unperturbed <span class="hlt">solar</span> <span class="hlt">wind</span> intervals, using magnetic field, electric field as well as density measurements from the Cluster spacecraft in order to identify the nature of the wave modes present, how frequent they are and try to determine whether one or more wave modes at different times. We examine the electric to magnetic field fluctuation ratio (δ E/δd B), the magnetic compressibility (δ B∥ /δ B) as well as density fluctuations using newly developed diagnostic techniques by Salem et al (2012) and Chen et al (2012). We look for variations of the nature and properties of these kinetic scale fluctuations with <span class="hlt">solar</span> <span class="hlt">wind</span> conditions, such as the plasma beta and the angle between the magnetic field and the flow velocity which controls the measured (spacecraft frame) frequency of the fluctuations. We discuss how these results would impact how the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma is heated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...829...88L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...829...88L"><span>Plasma-field Coupling at Small Length Scales in <span class="hlt">Solar</span> <span class="hlt">Wind</span> Near 1 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Livadiotis, G.; Desai, M. I.</p> <p>2016-10-01</p> <p>In collisionless plasmas such as the <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, the lower efficiency of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, tending toward the constant ℏ* (II) the transition is more efficient for larger thermal, Alfvén, or FMS speeds; (III) the fast <span class="hlt">solar</span> <span class="hlt">wind</span> is almost dispersionless, characterized by quasi-constant values of the FMS speed, while the slow <span class="hlt">wind</span> is subject to dispersion that is less effective for larger <span class="hlt">wind</span> or magnetosonic speeds; and (IV) the constant ℏ* is estimated with the best known precision, ℏ* ≈ (1.160 ± 0.083) × 10-22 Js.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29882534','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29882534"><span>The Dependence of the Peak Velocity of High-Speed <span class="hlt">Solar</span> <span class="hlt">Wind</span> Streams as Measured in the Ecliptic by <span class="hlt">ACE</span> and the STEREO satellites on the Area and Co-latitude of Their <span class="hlt">Solar</span> Source Coronal Holes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hofmeister, Stefan J; Veronig, Astrid; Temmer, Manuela; Vennerstrom, Susanne; Heber, Bernd; Vršnak, Bojan</p> <p>2018-03-01</p> <p>We study the properties of 115 coronal holes in the time range from August 2010 to March 2017, the peak velocities of the corresponding high-speed streams as measured in the ecliptic at 1 AU, and the corresponding changes of the Kp index as marker of their geoeffectiveness. We find that the peak velocities of high-speed streams depend strongly on both the areas and the co-latitudes of their <span class="hlt">solar</span> source coronal holes with regard to the heliospheric latitude of the satellites. Therefore, the co-latitude of their source coronal hole is an important parameter for the prediction of the high-speed stream properties near the Earth. We derive the largest <span class="hlt">solar</span> <span class="hlt">wind</span> peak velocities normalized to the coronal hole areas for coronal holes located near the <span class="hlt">solar</span> equator and that they linearly decrease with increasing latitudes of the coronal holes. For coronal holes located at latitudes ≳ 60°, they turn statistically to zero, indicating that the associated high-speed streams have a high chance to miss the Earth. Similarly, the Kp index per coronal hole area is highest for the coronal holes located near the <span class="hlt">solar</span> equator and strongly decreases with increasing latitudes of the coronal holes. We interpret these results as an effect of the three-dimensional propagation of high-speed streams in the heliosphere; that is, high-speed streams arising from coronal holes near the <span class="hlt">solar</span> equator propagate in direction toward and directly hit the Earth, whereas <span class="hlt">solar</span> <span class="hlt">wind</span> streams arising from coronal holes at higher <span class="hlt">solar</span> latitudes only graze or even miss the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1355780-benefits-colocating-concentrating-solar-power-wind','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1355780-benefits-colocating-concentrating-solar-power-wind"><span>Benefits of Colocating Concentrating <span class="hlt">Solar</span> Power and <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Sioshansi, Ramteen; Denholm, Paul</p> <p>2013-09-16</p> <p>Here, we analyze the potential benefits of colocating <span class="hlt">wind</span> and concentrating <span class="hlt">solar</span> 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 <span class="hlt">wind</span> and CSP: 1) the negative correlation between real-time <span class="hlt">wind</span> and <span class="hlt">solar</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM21C..07R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM21C..07R"><span>Dependence of Subsolar Magnetopause on <span class="hlt">Solar</span> <span class="hlt">Wind</span> Properties using the Magnetosphere Multiscale Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>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.</p> <p>2017-12-01</p> <p>The nature of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> obtained in the near Earth <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> Mach number conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950038009&hterms=foreshock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dforeshock','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950038009&hterms=foreshock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dforeshock"><span>Elsaesser variable analysis of fluctuations in the ion foreshock and undisturbed <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Labelle, James; Treumann, Rudolf A.; Marsch, Eckart</p> <p>1994-01-01</p> <p>Magnetohydrodynamics (MHD) fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> at 1 AU and in the ion foreshock in front of the Earth. Both observations take place under relatively strong <span class="hlt">solar</span> <span class="hlt">wind</span> flow speed conditions (approximately equal 600 km/s). In the undisturbed <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> data and provide additional insight into the nature of the ion foreshock turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUSMSH34B..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUSMSH34B..03C"><span>Turbulence and Waves as Sources for the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cranmer, S. R.</p> <p>2008-05-01</p> <p>Gene Parker's insights from 50 years ago provided the key causal link between energy deposition in the <span class="hlt">solar</span> corona and the acceleration of <span class="hlt">solar</span> <span class="hlt">wind</span> streams. However, the community is still far from agreement concerning the actual physical processes that give rise to this energy. It is still unknown whether the <span class="hlt">solar</span> <span class="hlt">wind</span> is fed by flux tubes that remain open (and are energized by footpoint-driven wavelike fluctuations) or if mass and energy is input more intermittently from closed loops into the open-field regions. No matter the relative importance of reconnections and loop-openings, though, we do know that waves and turbulent motions are present everywhere from the photosphere to the heliosphere, and it is important to determine how they affect the mean state of the plasma. In this presentation, I will give a summary of wave/turbulence models that seem to succeed in explaining the time-steady properties of the corona (and the fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span>). The coronal heating and <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration in these models comes from anisotropic turbulent cascade, which is driven by the partial reflection of low-frequency Alfven waves propagating along the open magnetic flux tubes. Specifically, a 2D model of coronal holes and streamers at <span class="hlt">solar</span> minimum reproduces the latitudinal bifurcation of slow and fast streams seen by Ulysses. The radial gradient of the Alfven speed affects where the waves are reflected and damped, and thus whether energy is deposited below or above Parker's critical point. As predicted by earlier studies, a larger coronal expansion factor gives rise to a slower and denser <span class="hlt">wind</span>, higher temperature at the coronal base, less intense Alfven waves at 1 AU, and correlative trends for commonly measured ratios of ion charge states and FIP-sensitive abundances that are in general agreement with observations. Finally, I will outline the types of future observations that would be most able to test and refine these ideas.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026545','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026545"><span>11- and 22-year variations of the cosmic ray density and of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chirkov, N. P.</p> <p>1985-01-01</p> <p>Cosmic ray density variations for 17-21 <span class="hlt">solar</span> activity cycles and the <span class="hlt">solar</span> <span class="hlt">wind</span> speed for 20-21 events are investigated. The 22-year <span class="hlt">solar</span> <span class="hlt">wind</span> speed recurrence was found in even and odd cycles. The 22-year variations of cosmic ray density were found to be opposite that of <span class="hlt">solar</span> <span class="hlt">wind</span> speed and <span class="hlt">solar</span> activity. The account of <span class="hlt">solar</span> <span class="hlt">wind</span> speed in 11-year variations significantly decreases the modulation region of cosmic rays when E = 10-20 GeV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100024507&hterms=Solar+still&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSolar%2Bstill','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100024507&hterms=Solar+still&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSolar%2Bstill"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Ablation of Terrestrial Planet Atmospheres</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moore, Thomas Earle; Fok, Mei-Ching H.; Delcourt, Dominique C.</p> <p>2009-01-01</p> <p>Internal plasma sources usually arise in planetary magnetospheres as a product of stellar ablation processes. With the ignition of a new star and the onset of its ultraviolet and stellar <span class="hlt">wind</span> emissions, much of the volatiles in the stellar system undergo a phase transition from gas to plasma. Condensation and accretion into a disk is replaced by radiation and stellar <span class="hlt">wind</span> ablation of volatile materials from the system- Planets or smaller bodies that harbor intrinsic magnetic fields develop an apparent shield against direct stellar <span class="hlt">wind</span> impact, but UV radiation still ionizes their gas phases, and the resulting internal plasmas serve to conduct currents to and from the central body along reconnected magnetic field linkages. Photoionization and thermalization of electrons warms the ionospheric topside, enhancing Jeans' escape of super-thermal particles, with ambipolar diffusion and acceleration. Moreover, observations and simulations of auroral processes at Earth indicate that <span class="hlt">solar</span> <span class="hlt">wind</span> energy dissipation is concentrated by the geomagnetic field by a factor of 10-100, enhancing heavy species plasma and gas escape from gravity, and providing more current carrying capacity. Thus internal plasmas enable coupling with the plasma, neutral gas and by extension, the entire body. The stellar <span class="hlt">wind</span> is locally loaded and slowed to develop the required power. The internal source plasma is accelerated and heated, inflating the magnetosphere as it seeks escape, and is ultimately blown away in the stellar <span class="hlt">wind</span>. Bodies with little sensible atmosphere may still produce an exosphere of sputtered matter when exposed to direct <span class="hlt">solar</span> <span class="hlt">wind</span> impact. Bodies with a magnetosphere and internal sources of plasma interact more strongly with the stellar <span class="hlt">wind</span> owing to the magnetic linkage between the two created by reconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110023419&hterms=geomagnetic+reversal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dgeomagnetic%2Breversal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110023419&hterms=geomagnetic+reversal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dgeomagnetic%2Breversal"><span><span class="hlt">Solar</span> Rotational Periodicities and the Semiannual Variation in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>, Radiation Belt, and Aurora</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Emery, Barbara A.; Richardson, Ian G.; Evans, David S.; Rich, Frederick J.; Wilson, Gordon R.</p> <p>2011-01-01</p> <p>The behavior of a number of <span class="hlt">solar</span> <span class="hlt">wind</span>, radiation belt, auroral and geomagnetic parameters is examined during the recent extended <span class="hlt">solar</span> minimum and previous <span class="hlt">solar</span> cycles, covering the period from January 1972 to July 2010. This period includes most of the <span class="hlt">solar</span> minimum between Cycles 23 and 24, which was more extended than recent <span class="hlt">solar</span> minima, with historically low values of most of these parameters in 2009. <span class="hlt">Solar</span> 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 <span class="hlt">solar</span> cycle, when HSS are the predominant <span class="hlt">solar</span> <span class="hlt">wind</span> structures. There were minima in the amplitudes of all <span class="hlt">solar</span> rotational periodicities near the end of each <span class="hlt">solar</span> minimum, as well as at the start of the reversal of the <span class="hlt">solar</span> magnetic field polarity at <span class="hlt">solar</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>-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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RScI...88k5112U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RScI...88k5112U"><span>A large ion beam device for laboratory <span class="hlt">solar</span> <span class="hlt">wind</span> studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulibarri, Zach; Han, Jia; Horányi, Mihály; Munsat, Tobin; Wang, Xu; Whittall-Scherfee, Guy; Yeo, Li Hsia</p> <p>2017-11-01</p> <p>The Colorado <span class="hlt">Solar</span> <span class="hlt">Wind</span> Experiment is a new device constructed at the Institute for Modeling Plasma, Atmospheres, and Cosmic Dust at the University of Colorado. A large cross-sectional Kaufman ion source is used to create steady state plasma flow to model the <span class="hlt">solar</span> <span class="hlt">wind</span> in an experimental vacuum chamber. The plasma beam has a diameter of 12 cm at the source, ion energies of up to 1 keV, and ion flows of up to 0.1 mA/cm2. Chamber pressure can be reduced to 4 × 10-5 Torr under operating conditions to suppress ion-neutral collisions and create a monoenergetic ion beam. The beam profile has been characterized by a Langmuir probe and an ion energy analyzer mounted on a two-dimensional translation stage. The beam profile meets the requirements for planned experiments that will study <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with lunar magnetic anomalies, the charging and dynamics of dust in the <span class="hlt">solar</span> <span class="hlt">wind</span>, plasma wakes and refilling, and the wakes of topographic features such as craters or boulders. This article describes the technical details of the device, initial operation and beam characterization, and the planned experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA03502&hterms=solar+energy+advantage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Benergy%2Badvantage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA03502&hterms=solar+energy+advantage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Benergy%2Badvantage"><span>Comet Borrelly Slows <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2001-01-01</p> <p>Over 1300 energy spectra taken on September 22, 2001 from the ion and electron instruments on NASA's Deep Space 1 span a region of 1,400,000 kilometers (870,000 miles) centered on the closest approach to the nucleus of comet Borrelly. A very strong interaction occurs between the <span class="hlt">solar</span> <span class="hlt">wind</span> (horizontal red bands to left and right in figure) and the comet's surrounding cloud of dust and gas, the coma. Near Deep Space 1's closest approach to the nucleus, the <span class="hlt">solar</span> <span class="hlt">wind</span> picked up charged water molecules from the coma (upper green band near the center), slowing the <span class="hlt">wind</span> sharply and creating the V-shaped energy structure at the center.<p/>Deep Space 1 completed its primary mission testing ion propulsion and 11 other advanced, high-risk technologies in September 1999. NASA extended the mission, taking advantage of the ion propulsion and other systems to undertake this chancy but exciting, and ultimately successful, encounter with the comet. More information can be found on the Deep Space 1 home page at http://nmp.jpl.nasa.gov/ds1/ .<p/>Deep Space 1 was launched in October 1998 as part of NASA's New Millennium Program, which is managed by JPL for NASA's Office of Space Science, Washington, D.C. The California Institute of Technology manages JPL for NASA.<p/></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003238&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbackground%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003238&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbackground%2Bwind"><span>Fading Coronal Structure and the Onset of Turbulence in the Young <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>DeForest, C. E.; Matthaeus, W. H.; Viall, N. M.; Cranmer, S. R.</p> <p>2016-01-01</p> <p>Above the top of the <span class="hlt">solar</span> corona, the young, slow <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> images. We present image sequences collected by the inner Heliospheric Imager instrument on board the <span class="hlt">Solar</span>-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 <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22667456-fading-coronal-structure-onset-turbulence-young-solar-wind','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22667456-fading-coronal-structure-onset-turbulence-young-solar-wind"><span>FADING CORONAL STRUCTURE AND THE ONSET OF TURBULENCE IN THE YOUNG <span class="hlt">SOLAR</span> <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>DeForest, C. E.; Matthaeus, W. H.; Viall, N. M.</p> <p></p> <p>Above the top of the <span class="hlt">solar</span> corona, the young, slow <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> images. We present image sequences collected by the inner Heliospheric Imager instrument on board the <span class="hlt">Solar</span>-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 <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040200985&hterms=HTML&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DHTML','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040200985&hterms=HTML&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DHTML"><span><span class="hlt">Wind</span> and IMP 8 <span class="hlt">Solar</span> <span class="hlt">Wind</span>, Magnetosheath and Shock Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p>The purpose of this project was to provide the community access to magnetosheath data near Earth. We provided 27 years of IMP 8 magnetosheath proton velocities, densities, and temperatures with our best (usually 1-min.) time resolution. IMP 8 crosses the magnetosheath twice each 125 day orbit, and we provided magnetosheath data for the roughly 27 years of data for which magnetometer data are also available (which are needed to reliably pick boundaries). We provided this 27 years of IMP 8 magnetosheath data to the NSSDC; this data is now integrated with the IMP 8 <span class="hlt">solar</span> <span class="hlt">wind</span> data with flags indicating whether each data point is in the <span class="hlt">solar</span> <span class="hlt">wind</span>, magnetosheath, or at the boundary between the two regions. The plasma speed, density, and temperature are provided for each magnetosheath point. These data are also available on the MIT web site ftp://space .mit.edu/pub/plasma/imp/www/imp.html. We provide ASCII time-ordered rows of data giving the observation time, the spacecraft position in GSE, the velocity is GSE, the density and temperature for protons. We also have analyzed and archived on our web site the <span class="hlt">Wind</span> magnetosheath plasma parameters. These consist of ascii files of the proton and alpha densities, speeds, and thermal speeds. These data are available at ftp://space.mit.edu/pub/plasma/<span class="hlt">wind</span>/sheath These are the two products promised in the work statement and they have been completed in full.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-12-18/pdf/2013-30036.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-12-18/pdf/2013-30036.pdf"><span>78 FR 76609 - Genesis <span class="hlt">Solar</span>, LLC; NRG Delta LLC; Mountain View <span class="hlt">Solar</span>, LLC; Pheasant Run <span class="hlt">Wind</span>, LLC; Pheasant Run...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2013-12-18</p> <p>... Delta LLC; Mountain View <span class="hlt">Solar</span>, LLC; Pheasant Run <span class="hlt">Wind</span>, LLC; Pheasant Run <span class="hlt">Wind</span> II, LLC; Tuscola <span class="hlt">Wind</span> II, LLC; Mountain <span class="hlt">Wind</span> Power, LLC; Mountain <span class="hlt">Wind</span> Power II, LLC; Summerhaven <span class="hlt">Wind</span>, LP; Notice of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018LRSP...15....1R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018LRSP...15....1R"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> stream interaction regions throughout the heliosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richardson, Ian G.</p> <p>2018-01-01</p> <p>This paper focuses on the interactions between the fast <span class="hlt">solar</span> <span class="hlt">wind</span> from coronal holes and the intervening slower <span class="hlt">solar</span> <span class="hlt">wind</span>, leading to the creation of stream interaction regions that corotate with the Sun and may persist for many <span class="hlt">solar</span> rotations. Stream interaction regions have been observed near 1 AU, in the inner heliosphere (at ˜ 0.3-1 AU) by the Helios spacecraft, in the outer and distant heliosphere by the Pioneer 10 and 11 and Voyager 1 and 2 spacecraft, and out of the ecliptic by Ulysses, and these observations are reviewed. Stream interaction regions accelerate energetic particles, modulate the intensity of Galactic cosmic rays and generate enhanced geomagnetic activity. The remote detection of interaction regions using interplanetary scintillation and white-light imaging, and MHD modeling of interaction regions will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SpWea..15.1490L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SpWea..15.1490L"><span>Data Assimilation in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Challenges and First Results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lang, Matthew; Browne, Philip; van Leeuwen, Peter Jan; Owens, Mathew</p> <p>2017-11-01</p> <p>Data assimilation (DA) is used extensively in numerical weather prediction (NWP) to improve forecast skill. Indeed, improvements in forecast skill in NWP models over the past 30 years have directly coincided with improvements in DA schemes. At present, due to data availability and technical challenges, DA is underused in space weather applications, particularly for <span class="hlt">solar</span> <span class="hlt">wind</span> prediction. This paper investigates the potential of advanced DA methods currently used in operational NWP centers to improve <span class="hlt">solar</span> <span class="hlt">wind</span> prediction. To develop the technical capability, as well as quantify the potential benefit, twin experiments are conducted to assess the performance of the Local Ensemble Transform Kalman Filter (LETKF) in the <span class="hlt">solar</span> <span class="hlt">wind</span> model ENLIL. Boundary conditions are provided by the Wang-Sheeley-Arge coronal model and synthetic observations of density, temperature, and momentum generated every 4.5 h at 0.6 AU. While in situ spacecraft observations are unlikely to be routinely available at 0.6 AU, these techniques can be applied to remote sensing of the <span class="hlt">solar</span> <span class="hlt">wind</span>, such as with Heliospheric Imagers or interplanetary scintillation. The LETKF can be seen to improve the state at the observation location and advect that improvement toward the Earth, leading to an improvement in forecast skill in near-Earth space for both the observed and unobserved variables. However, sharp gradients caused by the analysis of a single observation in space resulted in artificial wavelike structures being advected toward Earth. This paper is the first attempt to apply DA to <span class="hlt">solar</span> <span class="hlt">wind</span> prediction and provides the first in-depth analysis of the challenges and potential solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22667169-modeling-solar-wind-ulysses-voyager-new-horizons-spacecraft','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22667169-modeling-solar-wind-ulysses-voyager-new-horizons-spacecraft"><span>MODELING THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> AT THE ULYSSES , VOYAGER , AND NEW HORIZONS SPACECRAFT</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kim, T. K.; Pogorelov, N. V.; Zank, G. P.</p> <p></p> <p>The outer heliosphere is a dynamic region shaped largely by the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the interstellar medium. While interplanetary magnetic field and plasma observations by the Voyager spacecraft have significantly improved our understanding of this vast region, modeling the outer heliosphere still remains a challenge. We simulate the three-dimensional, time-dependent <span class="hlt">solar</span> <span class="hlt">wind</span> flow from 1 to 80 astronomical units (au), where the <span class="hlt">solar</span> <span class="hlt">wind</span> is assumed to be supersonic, using a two-fluid model in which protons and interstellar neutral hydrogen atoms are treated as separate fluids. We use 1 day averages of the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters frommore » the OMNI data set as inner boundary conditions to reproduce time-dependent effects in a simplified manner which involves interpolation in both space and time. Our model generally agrees with Ulysses data in the inner heliosphere and Voyager data in the outer heliosphere. Ultimately, we present the model <span class="hlt">solar</span> <span class="hlt">wind</span> parameters extracted along the trajectory of the New Horizons spacecraft. We compare our results with in situ plasma data taken between 11 and 33 au and at the closest approach to Pluto on 2015 July 14.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9963R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9963R"><span>Event Study of a Persistent Coronal Hole, its <span class="hlt">Solar</span> <span class="hlt">Wind</span> Signatures at L1, and Recurrent Relativistic Electron Enhancements at Geostationary Orbit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodriguez, Juan; Krista, Larisza</p> <p>2017-04-01</p> <p> persistent CH. This paper addresses the question: how do the properties of this particularly geoeffective CH and its <span class="hlt">solar</span> <span class="hlt">wind</span> manifestations at 1 AU vary from rotation to rotation and how is it distinguished from less geoeffective CHs (and ICMEs) during the same period? The Coronal Hole Automated Recognition and Monitoring (CHARM; Krista and Gallagher, 2009) algorithm is used to identify CHs and to quantify their physical properties (e.g., boundary, area, magnetic field strength and polarity). The Minor Storm (MiSt) algorithm is used to link the CHs to their in situ signatures (e.g., IMF, velocity, number density, temperature) observed by the Advanced Composition Explorer (<span class="hlt">ACE</span>) satellite. The properties of the CHs and associated geoeffective <span class="hlt">solar</span> <span class="hlt">wind</span> properties are evaluated and compared, as well as the Dst geomagnetic index. With these results, we determine whether any of the characteristics of the CHs and their in situ <span class="hlt">solar</span> <span class="hlt">wind</span> signatures distinguish them in their relative geoeffectiveness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22039309-three-dimensional-magnetohydrodynamic-modeling-solar-wind-including-pickup-protons-turbulence-transport','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22039309-three-dimensional-magnetohydrodynamic-modeling-solar-wind-including-pickup-protons-turbulence-transport"><span>THREE-DIMENSIONAL MAGNETOHYDRODYNAMIC MODELING OF THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> INCLUDING PICKUP PROTONS AND TURBULENCE TRANSPORT</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Usmanov, Arcadi V.; Matthaeus, William H.; Goldstein, Melvyn L., E-mail: arcadi.usmanov@nasa.gov</p> <p>2012-07-20</p> <p>To study the effects of interstellar pickup protons and turbulence on the structure and dynamics of the <span class="hlt">solar</span> <span class="hlt">wind</span>, we have developed a fully three-dimensional magnetohydrodynamic <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> protons, energy transfermore » from pickup protons to <span class="hlt">solar</span> <span class="hlt">wind</span> protons, and plasma heating by turbulent dissipation. Separate mass and energy equations are used for the <span class="hlt">solar</span> <span class="hlt">wind</span> and pickup protons, though a single momentum equation is employed under the assumption that the pickup protons are comoving with the <span class="hlt">solar</span> <span class="hlt">wind</span> protons. We compute the global structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8867E..0JL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8867E..0JL"><span><span class="hlt">ACE</span>-FTS on SCISAT: 10th year on-orbit anniversary</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lachance, Richard L.; Buijs, Henry L.; Soucy, Marc-André</p> <p>2013-09-01</p> <p>The Atmospheric Chemistry Experiment (<span class="hlt">ACE</span>) is a mission on-board the Canadian Space Agency's (CSA) SCISAT-1. <span class="hlt">ACE</span> is composed of a suite of instruments consisting of an infrared Fourier Transform Spectrometer (FTS) coupled with an auxiliary imager monitoring aerosols based on the extinction of <span class="hlt">solar</span> radiation using two filtered detectors (visible and near infrared). A suntracker is also included to provide fine pointing during occultation. A second instrument, MAESTRO, is a spectrophotometer covering the near ultra-violet to the near infrared. In combination, the instrument payload covers the spectral range from 0.25 to 13.3 μm. The <span class="hlt">ACE</span> mission came about from a need to better understand the chemical and dynamical processes that control the distribution of ozone in the upper troposphere and stratosphere, with particular emphasis on the Arctic region. Measurement of the vertical distribution of molecular species in these portions of the atmosphere permits elucidation of the key chemical and dynamical processes. The <span class="hlt">ACE</span>-FTS measures the vertical distributions of trace gases as well as polar stratospheric clouds, aerosols, and temperature by a <span class="hlt">solar</span> occultation technique from low earth orbit. By measuring <span class="hlt">solar</span> radiation at high spectral resolution as it passes through different layers of the atmosphere, the absorption thus measured provides information on vertical profiles of atmospheric constituents, temperature, and pressure. Detailed and sensitive vertical distribution of trace gases help to better understand the chemical processes not only for ozone formation and destruction but also for other dynamic processes in the atmosphere. The <span class="hlt">ACE</span>/SCISAT-1 satellite was successfully launched by NASA on August 12, 2003, and has been successfully operating since, now celebrating its 10th year on-orbit anniversary. This paper presents a summary of the heritage and development history of the <span class="hlt">ACE</span>-FTS instrument. Design challenges and solutions are related. The actual on</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900063357&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbackground%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900063357&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbackground%2Bwind"><span><span class="hlt">Solar</span> minimum Lyman alpha sky background observations from Pioneer Venus orbiter ultraviolet spectrometer - <span class="hlt">Solar</span> <span class="hlt">wind</span> latitude variation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ajello, J. M.</p> <p>1990-01-01</p> <p>Measurements of interplanetary H I Lyman alpha over a large portion of the celestial sphere were made at the recent <span class="hlt">solar</span> minimum by the Pioneer Venus orbiter ultraviolet spectrometer. These measurements were performed during a series of spacecraft maneuvers conducted to observe Halley's comet in early 1986. Analysis of these data using a model of the passage of interstellar <span class="hlt">wind</span> hydrogen through the <span class="hlt">solar</span> system shows that the rate of charge exchange with <span class="hlt">solar</span> <span class="hlt">wind</span> protons is 30 percent less over the <span class="hlt">solar</span> poles than in the ecliptic. This result is in agreement with a similar experiment performed with Mariner 10 at the previous <span class="hlt">solar</span> minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110016219&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dopen%2Bsource','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110016219&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dopen%2Bsource"><span>A Model fot the Sources of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antiochos, S. K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.</p> <p>2011-01-01</p> <p>Models for the origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> must account for two seemingly contradictory observations: the slow <span class="hlt">wind</span> has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow <span class="hlt">wind</span> also has large angular width, up to approx.60deg, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow <span class="hlt">wind</span> at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far from the heliospheric current sheet. We then use an MHD code and MDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span>, and magnetic field for a time period preceding the 2008 August 1 total <span class="hlt">solar</span> eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow <span class="hlt">wind</span>. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere and propose further tests of the model. Key words: <span class="hlt">solar</span> <span class="hlt">wind</span> - Sun: corona - Sun: magnetic topology</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA557860','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA557860"><span>The Distribution of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Speeds During <span class="hlt">Solar</span> Minimum: Calibration for Numerical <span class="hlt">Solar</span> <span class="hlt">Wind</span> Modeling Constraints on the Source of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span> (Postprint)</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2012-03-05</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>, increasing the flow speed [Leer and Holzer, 1980; Pneuman, 1980]. Using this model and a sim- plified</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1015690-solar-wind-protons-heavy-ions-sputtering-lunar-surface-materials','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1015690-solar-wind-protons-heavy-ions-sputtering-lunar-surface-materials"><span><span class="hlt">Solar-Wind</span> Protons and Heavy Ions Sputtering of Lunar Surface Materials</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Barghouty, N.; Meyer, Fred W; Harris, Peter R</p> <p>2011-01-01</p> <p>Lunar surface materials are exposed to {approx}1 keV/amu <span class="hlt">solar-wind</span> protons and heavy ions on almost continuous basis. As the lunar surface consists of mostly oxides, these materials suffer, in principle, both kinetic and potential sputtering due to the actions of the <span class="hlt">solar-wind</span> ions. Sputtering is an important mechanism affecting the composition of both the lunar surface and its tenuous exosphere. While the contribution of kinetic sputtering to the changes in the composition of the surface layer of these oxides is well understood and modeled, the role and implications of potential sputtering remain unclear. As new potential-sputtering data from multi-charged ionsmore » impacting lunar regolith simulants are becoming available from Oak Ridge National Laboratory's MIRF, we examine the role and possible implications of potential sputtering of Lunar KREEP soil. Using a non-equilibrium model we demonstrate that <span class="hlt">solar-wind</span> heavy ions induced sputtering is critical in establishing the timescale of the overall <span class="hlt">solar-wind</span> sputtering process of the lunar surface. We also show that potential sputtering leads to a more pronounced and significant differentiation between depleted and enriched surface elements. We briefly discuss the impacts of enhanced sputtering on the composition of the regolith and the exosphere, as well as of <span class="hlt">solar-wind</span> sputtering as a source of hydrogen and water on the moon.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750018425','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750018425"><span>Summary of NASA Lewis Research Center <span class="hlt">solar</span> heating and cooling and <span class="hlt">wind</span> energy programs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vernon, R. W.</p> <p>1975-01-01</p> <p>Plans for the construction and operation of a <span class="hlt">solar</span> heating and cooling system in conjunction with a office building being constructed at Langley Research Center, are discussed. Supporting research and technology includes: testing of <span class="hlt">solar</span> collectors with a <span class="hlt">solar</span> simulator, outdoor testing of collectors, property measurements of selective and nonselective coatings for <span class="hlt">solar</span> collectors, and a <span class="hlt">solar</span> model-systems test loop. The areas of a <span class="hlt">wind</span> energy program that are being conducted include: design and operation of a 100-kW experimental <span class="hlt">wind</span> generator, industry-designed and user-operated <span class="hlt">wind</span> generators in the range of 50 to 3000 kW, and supporting research and technology for large <span class="hlt">wind</span> energy systems. An overview of these activities is provided.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AIPC.1952b0025G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AIPC.1952b0025G"><span>Harmonic analysis and suppression in hybrid <span class="hlt">wind</span> & PV <span class="hlt">solar</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gupta, Tripti; Namekar, Swapnil</p> <p>2018-04-01</p> <p>The growing demand of electricity has led to produce power through non-conventional source of energy such as <span class="hlt">solar</span> energy, <span class="hlt">wind</span> energy, hydro power, energy through biogas and biomass etc. Hybrid system is taken to complement the shortcoming of either sources of energy. The proposed system is grid connected hybrid <span class="hlt">wind</span> and <span class="hlt">solar</span> system. A 2.1 MW Doubly fed Induction Generator (DFIG) has been taken for analysis of <span class="hlt">wind</span> farm whose rotor part is connected to two back-to-back converters. A 250 KW Photovoltaic (PV) array taken to analyze <span class="hlt">solar</span> farm where inverter is required to convert power from DC to AC since electricity generated through <span class="hlt">solar</span> PV is in the form of DC. Stability and reliability of the system is very important when the system is grid connected. Harmonics is the major Power quality issue which degrades the quality of power at load side. Harmonics in hybrid system arise through the use of power conversion unit. The other causes of harmonics are fluctuation in <span class="hlt">wind</span> speed and <span class="hlt">solar</span> irradiance. The power delivered to grid must be free from harmonics and within the limits specified by Indian grid codes. In proposed work, harmonic analysis of the hybrid system is performed in Electrical Transient Analysis program (ETAP) and single tuned harmonic filter is designed to maintain the utility grid harmonics within limits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002GeoRL..29.1171S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002GeoRL..29.1171S"><span>Evaluation of <span class="hlt">solar</span> Type II radio burst estimates of initial <span class="hlt">solar</span> <span class="hlt">wind</span> shock speed using a kinematic model of the <span class="hlt">solar</span> <span class="hlt">wind</span> on the April 2001 <span class="hlt">solar</span> event swarm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, W.; Dryer, M.; Fry, C. D.; Deehr, C. S.; Smith, Z.; Akasofu, S.-I.; Kartalev, M. D.; Grigorov, K. G.</p> <p>2002-04-01</p> <p>We compare simulation results of real time shock arrival time prediction with observations by the <span class="hlt">ACE</span> satellite for a series of <span class="hlt">solar</span> flares/coronal mass ejections which took place between 28 March and 18 April, 2001 on the basis of the Hakamada-Akasofu-Fry, version 2 (HAFv.2) model. It is found, via an ex post facto calculation, that the initial speed of shock waves as an input parameter of the modeling is crucial for the agreement between the observation and the simulation. The initial speed determined by metric Type II radio burst observations must be substantially reduced (30 percent in average) for most high-speed shock waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760017040','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760017040"><span>The large-scale magnetic field in the <span class="hlt">solar</span> <span class="hlt">wind</span>. [astronomical models of interplanetary magnetics and the <span class="hlt">solar</span> magnetic field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Ness, N. F.</p> <p>1976-01-01</p> <p>A literature review is presented of theoretical models of the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> are examined. The model of Parker is emphasized. This model shows the three dimensional magnetic field lines of the <span class="hlt">solar</span> <span class="hlt">wind</span> to have the form of spirals wrapped on cones. It is concluded that an out-of-the-ecliptic <span class="hlt">solar</span> probe mission would allow the testing and verification of the various theoretical models examined. Diagrams of the various models are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990028046&hterms=Open+Field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DOpen%2BField','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990028046&hterms=Open+Field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DOpen%2BField"><span>Signature of open magnetic field lines in the extended <span class="hlt">solar</span> corona and of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antonucci, E.; Giordano, S.; Benna, C.; Kohl, J. L.; Noci, G.; Michels, J.; Fineschi, S.</p> <p>1997-01-01</p> <p>The observations carried out with the ultraviolet coronagraph spectrometer onboard the <span class="hlt">Solar</span> and Heliospheric Observatory (SOHO) are discussed. The purpose of the observations was to determine the line of sight and radial velocity fields in coronal regions with different magnetic topology. The results showed that the regions where the high speed <span class="hlt">solar</span> <span class="hlt">wind</span> flows along open field lines are characterized by O VI 1032 and HI Lyman alpha 1216 lines. The global coronal maps of the line of sight velocity were reconstructed. The corona height, where the <span class="hlt">solar</span> <span class="hlt">wind</span> reaches 100 km/s, was determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810055592&hterms=energy+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Denergy%2Bconsumption','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810055592&hterms=energy+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Denergy%2Bconsumption"><span>Energy coupling between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Akasofu, S.-I.</p> <p>1981-01-01</p> <p>A description is given of the path leading to the first approximation expression for the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere energy coupling function (epsilon), which correlates well with the total energy consumption rate (U sub T) of the magnetosphere. It is shown that epsilon is the primary factor controlling the time development of magnetospheric substorms and storms. The finding of this particular expression epsilon indicates how the <span class="hlt">solar</span> <span class="hlt">wind</span> couples its energy to the magnetosphere; the <span class="hlt">solar</span> <span class="hlt">wind</span> and the magnetosphere make up a dynamo. In fact, the power generated by the dynamo can be identified as epsilon through the use of a dimensional analysis. In addition, the finding of epsilon suggests that the magnetosphere is closer to a directly driven system than to an unloading system which stores the generated energy before converting it to substorm and storm energies. The finding of epsilon and its implications is considered to have significantly advanced and improved the understanding of magnetospheric processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016043','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016043"><span>ROSAT Observations of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Charge Exchange with the Lunar Exosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Collier, Michael R.; Snowden, S. L.; Benna, M.; Carter, J. A.; Cravens, T. E.; Hills, H. Kent; Hodges, R. R.; Kuntz, K. D.; Porter, F. Scott; Read, A.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20120016043'); toggleEditAbsImage('author_20120016043_show'); toggleEditAbsImage('author_20120016043_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20120016043_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20120016043_hide"></p> <p>2012-01-01</p> <p>We analyze the ROSAT PSPC soft X-ray image of the Moon taken on 29 June 1990 by examining the radial profile of the count rate in three wedges, two wedges (one north and one south) 13-32 degrees off (19 degrees wide) the terminator towards the dark side and one wedge 38 degrees wide centered on the anti-<span class="hlt">solar</span> direction. The radial profiles of both the north and the south wedges show substantial limb brightening that is absent in the 38 degree wide antisolar wedge. An analysis of the count rate increase associated with the limb brightening shows that its magnitude is consistent with that expected due to <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange (SWCX) with the tenuous lunar atmosphere. Along with Mars, Venus, and Earth, the Moon represents another <span class="hlt">solar</span> system body at which <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange has been observed. This technique can be used to explore the <span class="hlt">solar</span> <span class="hlt">wind</span>-lunar interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH23D2703P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH23D2703P"><span>The <span class="hlt">Solar</span> <span class="hlt">Wind</span> from Pseudostreamers and their Environs: Opportunities for Observations with Parker <span class="hlt">Solar</span> Probe and <span class="hlt">Solar</span> Orbiter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panasenco, O.; Velli, M.; Panasenco, A.; Lionello, R.</p> <p>2017-12-01</p> <p>The <span class="hlt">solar</span> dynamo and photospheric convection lead to three main types of structures extending from the <span class="hlt">solar</span> surface into the corona - active regions, <span class="hlt">solar</span> filaments (prominences when observed at the limb) and coronal holes. These structures exist over a wide range of scales, and are interlinked with each other in evolution and dynamics. Active regions can form clusters of magnetic activity and the strongest overlie sunspots. In the decay of active regions, the boundaries separating opposite magnetic polarities (neutral lines) develop specific structures called filament channels above which filaments form. In the presence of flux imbalance decaying active regions can also give birth to lower latitude coronal holes. The accumulation of magnetic flux at coronal hole boundaries also creates conditions for filament formation: polar crown filaments are permanently present at the boundaries of the polar coronal holes. Mid-latitude and equatorial coronal holes - the result of active region evolution - can create pseudostreamers if other coronal holes of the same polarity are present. While helmet streamers form between open fields of opposite polarities, the pseudostreamer, characterized by a smaller coronal imprint, typically shows a more prominent straight ray or stalk extending from the corona. The pseudostreamer base at photospheric heights is multipolar; often one observes tripolar magnetic configurations with two neutral lines - where filaments can form - separating the coronal holes. Here we discuss the specific role of filament channels on pseudostreamer topology and on <span class="hlt">solar</span> <span class="hlt">wind</span> properties. 1D numerical analysis of pseudostreamers shows that the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> from around PSs depend on the presence/absence of filament channels, number of channels and chirality at thepseudostreamer base low in the corona. We review and model possible coronal magnetic configurations and <span class="hlt">solar</span> <span class="hlt">wind</span> plasma properties at different distances from the <span class="hlt">solar</span> surface that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750002821','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750002821"><span>Termination of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the hot, partially ionized interstellar medium. Ph.D. Thesis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lombard, C. K.</p> <p>1974-01-01</p> <p>Theoretical foundations for understanding the problem of the termination of the <span class="hlt">solar</span> <span class="hlt">wind</span> are reexamined in the light of most recent findings concerning the states of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, interstellar <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> along the upstream and downstream axes of flow with respect to the direction of the interstellar <span class="hlt">wind</span>. Predictions of <span class="hlt">solar</span> 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 <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/977319','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/977319"><span>Large Scale <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration in Germany</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ernst, Bernhard; Schreirer, Uwe; Berster, Frank</p> <p>2010-02-28</p> <p>This report provides key information concerning the German experience with integrating of 25 gigawatts of <span class="hlt">wind</span> and 7 gigawatts of <span class="hlt">solar</span> power capacity and mitigating its impacts on the electric power system. The report has been prepared based on information provided by the Amprion GmbH and 50Hertz Transmission GmbH managers and engineers to the Bonneville Power Administration (BPA) and Pacific Northwest National Laboratory representatives during their visit to Germany in October 2009. The trip and this report have been sponsored by the BPA Technology Innovation office. Learning from the German experience could help the Bonneville Power Administration engineers to comparemore » and evaluate potential new solutions for managing higher penetrations of <span class="hlt">wind</span> energy resources in their control area. A broader dissemination of this experience will benefit <span class="hlt">wind</span> and <span class="hlt">solar</span> resource integration efforts in the United States.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800016212&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwind%2Bmonitor','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800016212&hterms=wind+monitor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwind%2Bmonitor"><span>The magnetospheric electric field and convective processes as diagnostics of the IMF and <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kaye, S. M.</p> <p>1979-01-01</p> <p>Indirect measurements of the convection field as well as direct of the ionospheric electric field provide a means to at least monitor quanitatively <span class="hlt">solar</span> <span class="hlt">wind</span> processes. For instance, asymmetries in the ionospheric electric field and ionospheric Hall currents over the polar cap reflect the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> velocity, and thus may indicate the arrival at Earth of an interaction region in the <span class="hlt">solar</span> <span class="hlt">wind</span>. It is apparent that processes associated with the convention electric field may be used to predict large scale features in the <span class="hlt">solar</span> <span class="hlt">wind</span>; however, with present empirical knowledge it is not possible to make quantitative predictions of individual <span class="hlt">solar</span> <span class="hlt">wind</span> or IMF parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSH11A2216M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSH11A2216M"><span>Janus: Graphical Software for Analyzing In-Situ Measurements of <span class="hlt">Solar-Wind</span> Ions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maruca, B.; Stevens, M. L.; Kasper, J. C.; Korreck, K. E.</p> <p>2016-12-01</p> <p>In-situ observations of <span class="hlt">solar-wind</span> ions provide tremendous insights into the physics of space plasmas. Instrument on spacecraft measure distributions of ion energies, which can be processed into scientifically useful data (e.g., values for ion densities and temperatures). This analysis requires a strong, technical understanding of the instrument, so it has traditionally been carried out by the instrument teams using automated software that they had developed for that purpose. The automated routines are optimized for typical <span class="hlt">solar-wind</span> conditions, so they can fail to capture the complex (and scientifically interesting) microphysics of transient <span class="hlt">solar-wind</span> - such as coronal mass ejections (CME's) and co-rotating interaction regions (CIR's) - which are often better analyzed manually.This presentation reports on the ongoing development of Janus, a new software package for processing in-situ measurement of <span class="hlt">solar-wind</span> ions. Janus will provide user with an easy-to-use graphical user interface (GUI) for carrying out highly customized analyses. Transparent to the user, Janus will automatically handle the most technical tasks (e.g., the retrieval and calibration of measurements). For the first time, users with only limited knowledge about the instruments (e.g., non-instrumentalists and students) will be able to easily process measurements of <span class="hlt">solar-wind</span> ions. Version 1 of Janus focuses specifically on such measurements from the <span class="hlt">Wind</span> spacecraft's Faraday Cups and is slated for public release in time for this presentation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ApJ...853...85V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ApJ...853...85V"><span>3D Anisotropy of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulence, Tubes, or Ribbons?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verdini, Andrea; Grappin, Roland; Alexandrova, Olga; Lion, Sonny</p> <p>2018-01-01</p> <p>We study the anisotropy with respect to the local magnetic field of turbulent magnetic fluctuations at magnetofluid scales in the <span class="hlt">solar</span> <span class="hlt">wind</span>. Previous measurements in the fast <span class="hlt">solar</span> <span class="hlt">wind</span> obtained axisymmetric anisotropy, despite that the analysis method allows nonaxisymmetric structures. These results are probably contaminated by the <span class="hlt">wind</span> expansion that introduces another symmetry axis, namely, the radial direction, as indicated by recent numerical simulations. These simulations also show that while the expansion is strong, the principal fluctuations are in the plane perpendicular to the radial direction. Using this property, we separate 11 yr of <span class="hlt">Wind</span> spacecraft data into two subsets characterized by strong and weak expansion and determine the corresponding turbulence anisotropy. Under strong expansion, the small-scale anisotropy is consistent with the Goldreich & Sridhar critical balance. As in previous works, when the radial symmetry axis is not eliminated, the turbulent structures are field-aligned tubes. Under weak expansion, we find 3D anisotropy predicted by the Boldyrev model, that is, turbulent structures are ribbons and not tubes. However, the very basis of the Boldyrev phenomenology, namely, a cross-helicity increasing at small scales, is not observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>: the origin of the ribbon formation is unknown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JASTP.147...21M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JASTP.147...21M"><span><span class="hlt">Solar</span> activity variations of nocturnal thermospheric meridional <span class="hlt">winds</span> over Indian longitude sector</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Madhav Haridas, M. K.; Manju, G.; Arunamani, T.</p> <p>2016-09-01</p> <p>The night time F-layer base height information from ionosondes located at two equatorial stations Trivandrum (TRV 8.5°N, 77°E) and Sriharikota (SHAR 13.7°N, 80.2°E) spanning over two decades are used to derive the climatology of equatorial nocturnal Thermospheric Meridional <span class="hlt">Winds</span> (TMWs) prevailing during High <span class="hlt">Solar</span> Activity (HSA) and Low <span class="hlt">Solar</span> Activity (LSA) epochs. The important inferences from the analysis are 1) Increase in mean equatorward <span class="hlt">winds</span> observed during LSA compared to HSA during pre midnight hours; 25 m/s for VE (Vernal Equinox) and 20 m/s for SS (Summer Solstice), AE (autumnal Equinox) and WS (Winter Solstice). 2) Mean <span class="hlt">wind</span> response to <span class="hlt">Solar</span> Flux Unit (SFU) is established quantitatively for all seasons for pre-midnight hours; rate of increase is 0.25 m/s/SFU for VE, 0.2 m/s/SFU for SS and WS and 0.08 m/s/SFU for AE. 3) Theoretical estimates of <span class="hlt">winds</span> for the two epochs are performed and indicate the role of ion drag forcing as a major factor influencing TMWs. 4) Observed magnitude of <span class="hlt">winds</span> and rate of flux dependencies are compared to thermospheric <span class="hlt">wind</span> models. 5) Equinoctial asymmetry in TMWs is observed for HSA at certain times, with more equatorward <span class="hlt">winds</span> during AE. These observations lend a potential to parameterize the <span class="hlt">wind</span> components and effectively model the <span class="hlt">winds</span>, catering to <span class="hlt">solar</span> activity variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011NPGeo..18..287M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011NPGeo..18..287M"><span>Multifractal two-scale Cantor set model for slow <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence in the outer heliosphere during <span class="hlt">solar</span> maximum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Macek, W. M.; Wawrzaszek, A.</p> <p>2011-05-01</p> <p>To quantify <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence, we consider a generalized two-scale weighted Cantor set with two different scales describing nonuniform distribution of the kinetic energy flux between cascading eddies of various sizes. We examine generalized dimensions and the corresponding multifractal singularity spectrum depending on one probability measure parameter and two rescaling parameters. In particular, we analyse time series of velocities of the slow speed streams of the <span class="hlt">solar</span> <span class="hlt">wind</span> measured in situ by Voyager 2 spacecraft in the outer heliosphere during <span class="hlt">solar</span> maximum at various distances from the Sun: 10, 30, and 65 AU. This allows us to look at the evolution of multifractal intermittent scaling of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the distant heliosphere. Namely, it appears that while the degree of multifractality for the <span class="hlt">solar</span> <span class="hlt">wind</span> during <span class="hlt">solar</span> maximum is only weakly correlated with the heliospheric distance, but the multifractal spectrum could substantially be asymmetric in a very distant heliosphere beyond the planetary orbits. Therefore, one could expect that this scaling near the frontiers of the heliosphere should rather be asymmetric. It is worth noting that for the model with two different scaling parameters a better agreement with the <span class="hlt">solar</span> <span class="hlt">wind</span> data is obtained, especially for the negative index of the generalized dimensions. Therefore we argue that there is a need to use a two-scale cascade model. Hence we propose this model as a useful tool for analysis of intermittent turbulence in various environments and we hope that our general asymmetric multifractal model could shed more light on the nature of turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040171630','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040171630"><span>Wave-Particle Interactions As a Driving Mechanism for the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wagner, William J.</p> <p>2004-01-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>. As fluctuating electric fields in the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>: (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 <span class="hlt">solar</span> <span class="hlt">wind</span>. In the next section, we shall demonstrate that the velocity filtration effect is rather insignificant in comparison with that due to ion cyclotron resonance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22661260-energy-cascade-rate-compressible-fast-slow-solar-wind-turbulence','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22661260-energy-cascade-rate-compressible-fast-slow-solar-wind-turbulence"><span>Energy Cascade Rate in Compressible Fast and Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulence</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hadid, L. Z.; Sahraoui, F.; Galtier, S., E-mail: lina.hadid@lpp.polytechnique.fr</p> <p>2017-03-20</p> <p>Estimation of the energy cascade rate in the inertial range of <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>, 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 <span class="hlt">solar</span> <span class="hlt">wind</span>; (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 <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7838S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7838S"><span>Distribution Strategies for <span class="hlt">Solar</span> and <span class="hlt">Wind</span> Renewables in NW Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smedley, Andrew; Webb, Ann</p> <p>2017-04-01</p> <p>Whilst the UNFCCC Paris Agreement Climate change was ratified in November, 2016 saw the highest global temperature anomaly on record at 1.2°C above pre-industrial levels. As such there is urgent need to reduce CO2 emissions by a move away from fossil fuels and towards renewable electricity energy technologies. As the principal renewable technologies of <span class="hlt">solar</span> PV and <span class="hlt">wind</span> turbines contribute an increasing fraction to the electricity grid, questions of cumulative intermittency and the large-scale geographic distribution of each technology need to be addressed. In this study our initial emphasis is on a calculation of a relatively high spatial resolution (0.1° × 0.1°) daily gridded dataset of <span class="hlt">solar</span> irradiance data, over a 10 year period (2006-2015). This is achieved by coupling established sources of satellite data (MODIS SSF level2 instantaneous footprint data) to a well-validated radiative transfer model, here LibRadTran. We utilise both a morning and afternoon field for two cloud layers (optical depth and cloud fraction) interpolated to hourly grids, together with aerosol optical depth, topographic height and <span class="hlt">solar</span> zenith angle. These input parameters are passed to a 5-D LUT of LibRadTran results to construct hourly estimates of the <span class="hlt">solar</span> irradiance field, which is then integrated to a daily total. For the daily <span class="hlt">wind</span> resource we rely on the 6 hourly height-adjusted ECMWF ERA-Interim reanalysis <span class="hlt">wind</span> fields, but separated into onshore, offshore and deep water components. From these datasets of the <span class="hlt">solar</span> and <span class="hlt">wind</span> resources we construct 22 different distribution strategies for <span class="hlt">solar</span> PV and <span class="hlt">wind</span> turbines based on the long-term availability of each resource. Combining these distributions with the original daily gridded datasets enables each distribution strategy to be then assessed in terms of the day-to-day variability, the installed capacity required to maintain a baseline supply, and the relative proportions of each technology. Notably for the NW European area</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910069093&hterms=media+influence&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmedia%2Binfluence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910069093&hterms=media+influence&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmedia%2Binfluence"><span>Influence of the <span class="hlt">solar</span> <span class="hlt">wind</span>/interplanetary medium on Saturnian kilometric radiation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rucker, Helmut O.; Desch, M. D.</p> <p>1990-01-01</p> <p>Previous studies on the periodicities of the Saturnian kilometric radiation (SKR) suggested a considerable <span class="hlt">solar</span> <span class="hlt">wind</span> influence on the occurrence of SKR, so it was obvious to investigate the relationship between parameters of the <span class="hlt">solar</span> <span class="hlt">wind</span>/interplanetary medium and this Saturnian radio component. Voyager 2 data from the Plasma Science experiment, the Magnetometer experiment and the Planetary Radio Astronomy experiment were used to analyze the external control of SKR. Out of the examined quantities known to be important in controlling magnetospheric processes this investigation yielded a dominance of the <span class="hlt">solar</span> <span class="hlt">wind</span> momentum, ram pressure and kinetic energy flux, in stimulating SKR and controlling its activity and emitted energy, and confirmed the results of the Voyager 1 analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JGRA..107.1383V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JGRA..107.1383V"><span>Long-term-average, <span class="hlt">solar</span> cycle, and seasonal response of magnetospheric energetic electrons to the <span class="hlt">solar</span> <span class="hlt">wind</span> speed</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vassiliadis, D.; Klimas, A. J.; Kanekal, S. G.; Baker, D. N.; Weigel, R. S.</p> <p>2002-11-01</p> <p>Among the interplanetary activity parameters the <span class="hlt">solar</span> <span class="hlt">wind</span> speed is the one best correlated with the energetic electron fluxes in the inner magnetosphere. We examine the radial and temporal characteristics of the 2-6 MeV electron response, approximating it in this paper with linear filters. The filter response is parameterized by the time delay (τ), measured from the time of <span class="hlt">solar</span> <span class="hlt">wind</span> impact, and the L shell (L). We examine <span class="hlt">solar</span> cycle and seasonal effects using an 8-year-long database of <span class="hlt">Solar</span>, Anomalous, and Magnetospheric Particle Explorer (SAMPEX)/ Proton Electron Telescope (PET) measurements at the radial range L = 1.1-10. The main peak P1 of the long-term-average response is at (τ, L) = (2, 5.3) and has a simultaneous response over a wide range of radial distances, ΔL = 5. The duration of the response after the peak is inversely proportional to the L shell. The central part of the inner magnetosphere (L = 3.7-5.75) has a much more prolonged response (>10 days) than other parts. Prior to the main response, P1, a brief response, P0, of typically lower amplitude appears at (τ, L) = (0, 3), probably as a quasi-adiabatic response to the compression of the magnetosphere by the <span class="hlt">solar</span> <span class="hlt">wind</span> pressure. Over the <span class="hlt">solar</span> cycle the variation in <span class="hlt">solar</span> <span class="hlt">wind</span> input results in a systematic change of the position, amplitude, radial extent, and duration of the two peaks: during <span class="hlt">solar</span> <span class="hlt">wind</span> minimum the quasi-adiabatic peak disappears, and the radial size of the responding region decreases; both are responses to low-density, high-speed streams. During <span class="hlt">solar</span> minimum, the duration is at least 3 days (30%) longer than average, probably due to the sustained <span class="hlt">solar</span> <span class="hlt">wind</span> input. Systematic variations appear also as a function of season due to several magnetic and fluid effects. During equinoxes the coupling is stronger, and the duration is longer (by at least 2 days) compared to solstices. Between the two equinoxes the fall response has a significantly higher amplitude and longer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSH31C2746P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSH31C2746P"><span>Non-Extensive Statistical Analysis of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electric, Magnetic Fields and <span class="hlt">Solar</span> Energetic Particle time series.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pavlos, G. P.; Malandraki, O.; Khabarova, O.; Livadiotis, G.; Pavlos, E.; Karakatsanis, L. P.; Iliopoulos, A. C.; Parisis, K.</p> <p>2017-12-01</p> <p>In this work we study the non-extensivity of <span class="hlt">Solar</span> <span class="hlt">Wind</span> space plasma by using electric-magnetic field data obtained by in situ spacecraft observations at different dynamical states of <span class="hlt">solar</span> <span class="hlt">wind</span> system especially in interplanetary coronal mass ejections (ICMEs), Interplanetary shocks, magnetic islands, or near the Earth Bow shock. Especially, we study the energetic particle non extensive fractional acceleration mechanism producing kappa distributions as well as the intermittent turbulence mechanism producing multifractal structures related with the Tsallis q-entropy principle. We present some new and significant results concerning the dynamics of ICMEs observed in the near Earth at L1 <span class="hlt">solar</span> <span class="hlt">wind</span> environment, as well as its effect in Earth's magnetosphere as well as magnetic islands. In-situ measurements of energetic particles at L1 are analyzed, in response to major <span class="hlt">solar</span> eruptive events at the Sun (intense flares, fast CMEs). The statistical characteristics are obtained and compared for the <span class="hlt">Solar</span> Energetic Particles (SEPs) originating at the Sun, the energetic particle enhancements associated with local acceleration during the CME-driven shock passage over the spacecraft (Energetic Particle Enhancements, ESPs) as well as the energetic particle signatures observed during the passage of the ICME. The results are referred to Tsallis non-extensive statistics and in particular to the estimation of Tsallis q-triplet, (qstat, qsen, qrel) of electric-magnetic field and the kappa distributions of <span class="hlt">solar</span> energetic particles time series of the ICME, magnetic islands, resulting from the <span class="hlt">solar</span> eruptive activity or the internal <span class="hlt">Solar</span> <span class="hlt">Wind</span> dynamics. Our results reveal significant differences in statistical and dynamical features, indicating important variations of the magnetic field dynamics both in time and space domains during the shock event, in terms of rate of entropy production, relaxation dynamics and non-equilibrium meta-stable stationary states.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JASTP.102..185O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JASTP.102..185O"><span>The dispersion analysis of drift velocity in the study of <span class="hlt">solar</span> <span class="hlt">wind</span> flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olyak, Maryna</p> <p>2013-09-01</p> <p>In this work I consider a method for the study of the <span class="hlt">solar</span> <span class="hlt">wind</span> flows at distances from the Sun more than 1 AU. The method is based on the analysis of drift velocity dispersion that was obtained from the simultaneous scintillation observations in two antennas. I considered dispersion dependences for different models of the <span class="hlt">solar</span> <span class="hlt">wind</span>, and I defined its specificity for each model. I have determined that the presence of several <span class="hlt">solar</span> <span class="hlt">wind</span> flows significantly affects the shape and the slope of the dispersion curve. The maximum slope angle is during the passage of the fast <span class="hlt">solar</span> <span class="hlt">wind</span> flow near the Earth. If a slow flow passes near the Earth, the slope of the dispersion curve decreases. This allows a more precise definition of the velocity and flow width compared to the traditional scintillation method. Using the comparison of experimental and theoretical dispersion curves, I calculated the velocity and width of <span class="hlt">solar</span> <span class="hlt">wind</span> flows and revealed the presence of significant velocity fluctuations which accounted for about 60% of the average velocity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSH51B2230P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSH51B2230P"><span>Statistical analysis of dispersion relations in turbulent <span class="hlt">solar</span> <span class="hlt">wind</span> fluctuations using Cluster data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perschke, C.; Narita, Y.</p> <p>2012-12-01</p> <p>Multi-spacecraft measurements enable us to resolve three-dimensional spatial structures without assuming Taylor's frozen-in-flow hypothesis. This is very useful to study frequency-wave vector diagram in <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence through direct determination of three-dimensional wave vectors. The existence and evolution of dispersion relation and its role in fully-developed plasma turbulence have been drawing attention of physicists, in particular, if <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence represents kinetic Alfvén or whistler mode as the carrier of spectral energy among different scales through wave-wave interactions. We investigate <span class="hlt">solar</span> <span class="hlt">wind</span> intervals of Cluster data for various flow velocities with a high-resolution wave vector analysis method, Multi-point Signal Resonator technique, at the tetrahedral separation about 100 km. Magnetic field data and ion data are used to determine the frequency- wave vector diagrams in the co-moving frame of the <span class="hlt">solar</span> <span class="hlt">wind</span>. We find primarily perpendicular wave vectors in <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence which justify the earlier discussions about kinetic Alfvén or whistler wave. The frequency- wave vector diagrams confirm (a) wave vector anisotropy and (b) scattering in frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4354106','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4354106"><span>Full-Sun observations for identifying the source of the slow <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Brooks, David H.; Ugarte-Urra, Ignacio; Warren, Harry P.</p> <p>2015-01-01</p> <p>Fast (>700 km s−1) and slow (~400 km s−1) <span class="hlt">winds</span> stream from the Sun, permeate the heliosphere and influence the near-Earth environment. While the fast <span class="hlt">wind</span> is known to emanate primarily from polar coronal holes, the source of the slow <span class="hlt">wind</span> remains unknown. Here we identify possible sites of origin using a slow <span class="hlt">solar</span> <span class="hlt">wind</span> source map of the entire Sun, which we construct from specially designed, full-disk observations from the Hinode satellite, and a magnetic field model. Our map provides a full-Sun observation that combines three key ingredients for identifying the sources: velocity, plasma composition and magnetic topology and shows them as <span class="hlt">solar</span> <span class="hlt">wind</span> composition plasma outflowing on open magnetic field lines. The area coverage of the identified sources is large enough that the sum of their mass contributions can explain a significant fraction of the mass loss rate of the <span class="hlt">solar</span> <span class="hlt">wind</span>. PMID:25562705</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120002023','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120002023"><span>Magnetofluid Simulations of the Global <span class="hlt">Solar</span> <span class="hlt">Wind</span> Including Pickup Ions and Turbulence Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvyn L.; Usmanov, Arcadi V.; Matthaeus, William H.</p> <p>2011-01-01</p> <p>I will describe a three-dimensional magnetohydrodynamic model of the <span class="hlt">solar</span> <span class="hlt">wind</span> that takes into account turbulent heating of the <span class="hlt">wind</span> by velocity and magnetic fluctuations as well as a variety of effects produced by interstellar pickup protons. In this report, the interstellar pickup protons are treated as one fluid and the protons and electrons are treated together as a second fluid. The model equations include a Reynolds decomposition of the plasma velocity and magnetic field into mean and fluctuating quantities, as well as energy transfer from interstellar pickup protons to <span class="hlt">solar</span> <span class="hlt">wind</span> protons that results in the deceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span>. The model is used to simulate the global steady-state structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the region from 0.3 to 100 AU. Where possible, the model is compared with Voyager data. Initial results from generalization to a three-fluid model is described elsewhere in this session.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070011610&hterms=lazarus&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070011610&hterms=lazarus&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlazarus"><span><span class="hlt">Solar</span> <span class="hlt">Wind</span> Proton Temperature Anisotropy: Linear Theory and <span class="hlt">WIND</span>/SWE Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hellinger, P.; Travnicek, P.; Kasper, J. C.; Lazarus, A. J.</p> <p>2006-01-01</p> <p>We present a comparison between <span class="hlt">WIND</span>/SWE observations (Kasper et al., 2006) of beta parallel to p and T perpendicular to p/T parallel to p (where beta parallel to p is the proton parallel beta and T perpendicular to p and T parallel to p are the perpendicular and parallel proton are the perpendicular and parallel proton temperatures, respectively; here parallel and perpendicular indicate directions with respect to the ambient magnetic field) and predictions of the Vlasov linear theory. In the slow <span class="hlt">solar</span> <span class="hlt">wind</span>, the observed proton temperature anisotropy seems to be constrained by oblique instabilities, by the mirror one and the oblique fire hose, contrary to the results of the linear theory which predicts a dominance of the proton cyclotron instability and the parallel fire hose. The fast <span class="hlt">solar</span> <span class="hlt">wind</span> core protons exhibit an anticorrelation between beta parallel to c and T perpendicular to c/T parallel to c (where beta parallel to c is the core proton parallel beta and T perpendicular to c and T parallel to c are the perpendicular and parallel core proton temperatures, respectively) similar to that observed in the HELIOS data (Marsch et al., 2004).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021368&hterms=solar+geometry&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsolar%2Bgeometry','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021368&hterms=solar+geometry&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsolar%2Bgeometry"><span>Self consistent MHD modeling of the <span class="hlt">solar</span> <span class="hlt">wind</span> from coronal holes with distinct geometries</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stewart, G. A.; Bravo, S.</p> <p>1995-01-01</p> <p>Utilizing an iterative scheme, a self-consistent axisymmetric MHD model for the <span class="hlt">solar</span> <span class="hlt">wind</span> has been developed. We use this model to evaluate the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> issuing from the open polar coronal hole regions of the Sun, during <span class="hlt">solar</span> minimum. We explore the variation of <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27694887','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27694887"><span>Earth's magnetosphere and outer radiation belt under sub-Alfvénic <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lugaz, Noé; Farrugia, Charles J; Huang, Chia-Lin; Winslow, Reka M; Spence, Harlan E; Schwadron, Nathan A</p> <p>2016-10-03</p> <p>The interaction between Earth's magnetic field and the <span class="hlt">solar</span> <span class="hlt">wind</span> results in the formation of a collisionless bow shock 60,000-100,000 km upstream of our planet, as long as the <span class="hlt">solar</span> <span class="hlt">wind</span> fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling which is unusual for planets in our <span class="hlt">solar</span> system but may be common for close-in extrasolar planets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29398983','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29398983"><span>Data Assimilation in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Challenges and First Results.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lang, Matthew; Browne, Philip; van Leeuwen, Peter Jan; Owens, Mathew</p> <p>2017-11-01</p> <p>Data assimilation (DA) is used extensively in numerical weather prediction (NWP) to improve forecast skill. Indeed, improvements in forecast skill in NWP models over the past 30 years have directly coincided with improvements in DA schemes. At present, due to data availability and technical challenges, DA is underused in space weather applications, particularly for <span class="hlt">solar</span> <span class="hlt">wind</span> prediction. This paper investigates the potential of advanced DA methods currently used in operational NWP centers to improve <span class="hlt">solar</span> <span class="hlt">wind</span> prediction. To develop the technical capability, as well as quantify the potential benefit, twin experiments are conducted to assess the performance of the Local Ensemble Transform Kalman Filter (LETKF) in the <span class="hlt">solar</span> <span class="hlt">wind</span> model ENLIL. Boundary conditions are provided by the Wang-Sheeley-Arge coronal model and synthetic observations of density, temperature, and momentum generated every 4.5 h at 0.6 AU. While in situ spacecraft observations are unlikely to be routinely available at 0.6 AU, these techniques can be applied to remote sensing of the <span class="hlt">solar</span> <span class="hlt">wind</span>, such as with Heliospheric Imagers or interplanetary scintillation. The LETKF can be seen to improve the state at the observation location and advect that improvement toward the Earth, leading to an improvement in forecast skill in near-Earth space for both the observed and unobserved variables. However, sharp gradients caused by the analysis of a single observation in space resulted in artificial wavelike structures being advected toward Earth. This paper is the first attempt to apply DA to <span class="hlt">solar</span> <span class="hlt">wind</span> prediction and provides the first in-depth analysis of the challenges and potential solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Ge%26Ae..57..512N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Ge%26Ae..57..512N"><span>Does magnetic storm generation depend on the <span class="hlt">solar</span> <span class="hlt">wind</span> type?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nikolaeva, N. S.; Yermolaev, Yu. I.; Lodkina, I. G.; Yermolaev, M. Yu.</p> <p>2017-09-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> types. In this work, we study the generation efficiency of the main phase of a storm by different <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> types are to be studied further.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..422..113P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..422..113P"><span>Tsallis non-extensive statistics and <span class="hlt">solar</span> <span class="hlt">wind</span> plasma complexity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pavlos, G. P.; Iliopoulos, A. C.; Zastenker, G. N.; Zelenyi, L. M.; Karakatsanis, L. P.; Riazantseva, M. O.; Xenakis, M. N.; Pavlos, E. G.</p> <p>2015-03-01</p> <p>This article presents novel results revealing non-equilibrium phase transition processes in the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma during a strong shock event, which took place on 26th September 2011. <span class="hlt">Solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> 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).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P51C2600L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P51C2600L"><span>Analysis of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Precipitation on Mars Using MAVEN/SWIA Observations of Spacecraft-Scattered Ions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lue, C.; Halekas, J. S.</p> <p>2017-12-01</p> <p>Particle sensors on the MAVEN spacecraft (SWIA, SWEA, STATIC) observe precipitating <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> energy, traveling away from the Sun. The observations can be explained by the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> precipitation dynamics at Mars, and can also be used to monitor the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>. 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 <span class="hlt">solar</span> <span class="hlt">wind</span> scattering off the SWIA aperture structure, the radome and the spacecraft body. We find a broad scattered-ion energy spectrum up to the <span class="hlt">solar</span> <span class="hlt">wind</span> energy, displaying increased energy loss and reduced flux with increasing scattering angle, allowing correlations with the <span class="hlt">solar</span> <span class="hlt">wind</span> direction, energy, and flux. We develop models that can be used to predict the scattered signal based on the direct <span class="hlt">solar</span> <span class="hlt">wind</span> observations or to infer the <span class="hlt">solar</span> <span class="hlt">wind</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020006321&hterms=micro+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmicro%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020006321&hterms=micro+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmicro%2Bwind"><span>Exploration of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Acceleration Region Using Interplanetary Scintillation of Water Vapor Maser Source and Quasars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tokumaru, Munetoshi; Yamauchi, Yohei; Kondo, Tetsuro</p> <p>2001-01-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>, which is the key region for the study of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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. <span class="hlt">Solar</span> <span class="hlt">wind</span> speeds derived from Kashima IPS data suggest that the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration takes place at radial distances between 10 and 30 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration region. While the <span class="hlt">solar</span> <span class="hlt">wind</span> in the maximum phase appears to be dominated by the slow <span class="hlt">wind</span>, fast and rarefied <span class="hlt">winds</span> associated with the coronal holes were found to develop significantly at high latitudes as the <span class="hlt">solar</span> activity declined. Nevertheless, the Kashima data suggests that the location of the acceleration region is stable throughout the <span class="hlt">solar</span> cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020011026&hterms=quasar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dquasar','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020011026&hterms=quasar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dquasar"><span>Exploration of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Acceleration Region Using Interplanetary Scintillation of Water Vapor Maser Source and Quasars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tokumaru, Munetoshi; Yamauchi, Yohei; Kondo, Tetsuro</p> <p>2001-01-01</p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span>, which is the key region for the study of the <span class="hlt">solar</span> <span class="hlt">wind</span> 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. <span class="hlt">Solar</span> <span class="hlt">wind</span> velocities derived from Kashima IPS data suggest that the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration takes place at radial distances between 10 and 30 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration region. While the <span class="hlt">solar</span> <span class="hlt">wind</span> in the maximum phase appears to be dominated by the slow <span class="hlt">wind</span>, fast and rarefied <span class="hlt">winds</span> associated with coronal holes are found to develop significantly at high latitudes as the <span class="hlt">solar</span> activity declines. Nevertheless, Kashima data suggests that the location of the acceleration region is stable throughout the <span class="hlt">solar</span> cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.6925E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.6925E"><span>Survey of the spectral properties of turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span>, the magnetospheres of Venus and Earth, at <span class="hlt">solar</span> minimum and maximum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Echim, Marius M.</p> <p>2014-05-01</p> <p>In the framework of the European FP7 project STORM ("<span class="hlt">Solar</span> system plasma Turbulence: Observations, inteRmittency and Multifractals") we analyze the properties of turbulence in various regions of the <span class="hlt">solar</span> system, for the minimum and respectively maximum of the <span class="hlt">solar</span> 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 <span class="hlt">solar</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> (from Ulysses, Cluster, Venus Express) and at the interface of planetary magnetospheres with the <span class="hlt">solar</span> <span class="hlt">wind</span> (from Venus Express, Cluster). Ulysses provides data in the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">wind</span>. We analyzed Venus Express data close to the orbital apogee, in the <span class="hlt">solar</span> <span class="hlt">wind</span>, at 0.72 AU, and in the Venus magnetosheath. We investigated Cluster data in the <span class="hlt">solar</span> <span class="hlt">wind</span> (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 <span class="hlt">solar</span> <span class="hlt">wind</span> data bases (one for the <span class="hlt">solar</span> maximum, 1999-2001, two for the <span class="hlt">solar</span> minimum, 1997-1998 and respectively, 2007-2008), and two planetary databases (one for the <span class="hlt">solar</span> maximum, 2000-2001, that includes PSD obtained in the terrestrial magnetosphere, and one for the <span class="hlt">solar</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/15004472','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/15004472"><span><span class="hlt">Wind</span> and <span class="hlt">Solar</span> Resource Assessment of Sri Lanka and the Maldives (CD-ROM)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Elliott, D.; Schwartz, M.; Scott, G.</p> <p>2003-08-01</p> <p>The <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Resource Assessment of Sri Lanka and the Maldives CD contains an electronic version of <span class="hlt">Wind</span> Energy Resource Atlas of Sri Lanka and the Maldives (NREL/TP-500-34518), <span class="hlt">Solar</span> Resource Assessment for Sri Lanka and the Maldives (NREL/TO-710-34645), Sri Lanka <span class="hlt">Wind</span> Farm Analysis and Site Selection Assistance (NREL/SR-500-34646), GIS Data Viewer (software and data files with a readme file), and Hourly <span class="hlt">Solar</span> and Typical Meteorological Year Data with a readme file.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9519L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9519L"><span>Influence of interplanetary <span class="hlt">solar</span> <span class="hlt">wind</span> sector polarity on the ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>liu, jing</p> <p>2014-05-01</p> <p>Knowledge of <span class="hlt">solar</span> sector polarity effects on the ionosphere may provide some clues in understanding of the ionospheric day-to-day variability. A <span class="hlt">solar</span>-terrestrial connection ranging from <span class="hlt">solar</span> sector boundary (SB) crossings, geomagnetic disturbance and ionospheric perturbations has been demonstrated. The increases in interplanetary <span class="hlt">solar</span> <span class="hlt">wind</span> speed within three days are seen after SB crossings, while the decreases in <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure and magnetic field intensity immediately after SB crossings are confirmed by the superposed epoch analysis results. Furthermore, the interplanetary magnetic field (IMF) Bz component turns from northward to southward in March equinox and June solstice as the Earth passes from a <span class="hlt">solar</span> sector of outward to inward directed magnetic fields, whereas the reverse situation occurs for the transition from toward to away sectors. The F2 region critical frequency (foF2) covering about four <span class="hlt">solar</span> cycles and total electron content (TEC) during 1998-2011 are utilized to extract the related information, revealing that they are not modified significantly and vary within the range of 15% on average. The responses of the ionospheric TEC to SB crossings exhibit complex temporal and spatial variations and have strong dependencies on season, latitude, and <span class="hlt">solar</span> cycle. This effect is more appreciable in equinoctial months than in solstitial months, which is mainly caused by larger southward Bz components in equinox. In September equinox, latitudinal profile of relative variations of foF2 at noon is featured by depressions at high latitudes and enhancements in low-equatorial latitudes during IMF away sectors. The negative phase of foF2 is delayed at <span class="hlt">solar</span> minimum relative to it during other parts of <span class="hlt">solar</span> cycle, which might be associated with the difference in longevity of major interplanetary <span class="hlt">solar</span> <span class="hlt">wind</span> drivers perturbing the Earth's environment in different phases of <span class="hlt">solar</span> cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SoPh..292...92A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SoPh..292...92A"><span>The Role of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Structures in the Generation of ULF Waves in the Inner Magnetosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alves, L. R.; Souza, V. M.; Jauer, P. R.; da Silva, L. A.; Medeiros, C.; Braga, C. R.; Alves, M. V.; Koga, D.; Marchezi, J. P.; de Mendonça, R. R. S.; Dallaqua, R. S.; Barbosa, M. V. G.; Rockenbach, M.; Dal Lago, A.; Mendes, O.; Vieira, L. E. A.; Banik, M.; Sibeck, D. G.; Kanekal, S. G.; Baker, D. N.; Wygant, J. R.; Kletzing, C. A.</p> <p>2017-07-01</p> <p>The plasma of the <span class="hlt">solar</span> <span class="hlt">wind</span> incident upon the Earth's magnetosphere can produce several types of geoeffective events. Among them, an important phenomenon consists of the interrelation of the magnetospheric-ionospheric current systems and the charged-particle population of the Earth's Van Allen radiation belts. Ultra-low-frequency (ULF) waves resonantly interacting with such particles have been claimed to play a major role in the energetic particle flux changes, particularly at the outer radiation belt, which is mainly composed of electrons at relativistic energies. In this article, we use global magnetohydrodynamic simulations along with in situ and ground-based observations to evaluate the ability of two different <span class="hlt">solar</span> <span class="hlt">wind</span> transient (SWT) events to generate ULF (few to tens of mHz) waves in the equatorial region of the inner magnetosphere. Magnetic field and plasma data from the Advanced Composition Explorer (<span class="hlt">ACE</span>) satellite were used to characterize these two SWT events as being a sector boundary crossing (SBC) on 24 September 2013, and an interplanetary coronal mass ejection (ICME) in conjunction with a shock on 2 October 2013. Associated with these events, the twin Van Allen Probes measured a depletion of the outer belt relativistic electron flux concurrent with magnetic and electric field power spectra consistent with ULF waves. Two ground-based observatories apart in 90°C longitude also showed evidence of ULF-wave activity for the two SWT events. Magnetohydrodynamic (MHD) simulation results show that the ULF-like oscillations in the modeled electric and magnetic fields observed during both events are a result from the SWT coupling to the magnetosphere. The analysis of the MHD simulation results together with the observations leads to the conclusion that the two SWT structures analyzed in this article can be geoeffective on different levels, with each one leading to distinct ring current intensities, but both SWTs are related to the same disturbance in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930049659&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dbackground%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930049659&hterms=background+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dbackground%2Bwind"><span>Weakly inhomogeneous MHD turbulence and transport of <span class="hlt">solar</span> <span class="hlt">wind</span> fluctuations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matthaeus, W. H.; Zhou, Y.; Oughton, S.; Zank, G. P.</p> <p>1992-01-01</p> <p>An evaluation is conducted of recent theories of small-scale MHD turbulence transport in an inhomogeneous background that are pertinent to the evolution of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence. Attention is given to the WKB formalism that has been used in many <span class="hlt">solar</span> <span class="hlt">wind</span>-related physics applications, with a view to its shortcomings. Also discussed are the structure of two-scale transport theories, and their relationship to WKB theory in light of multiple-scales analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020034466','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020034466"><span>Obtaining Reliable Predictions of Terrestrial Energy Coupling From Real-Time <span class="hlt">Solar</span> <span class="hlt">Wind</span> Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weimer, Daniel R.</p> <p>2002-01-01</p> <p>Measurements of the interplanetary magnetic field (IMF) from the <span class="hlt">ACE</span> (Advanced Composition Explorer), <span class="hlt">Wind</span>, IMP-8 (Interplanetary Monitoring Platform), and Geotail spacecraft have revealed that the IMF variations are contained in phase planes that are tilted with respect to the propagation direction, resulting in continuously variable changes in propagation times between spacecraft, and therefore, to the Earth. Techniques for using 'minimum variance analysis' have been developed in order to be able to measure the phase front tilt angles, and better predict the actual propagation times from the L1 orbit to the Earth, using only the real-time IMF measurements from one spacecraft. The use of empirical models with the IMF measurements at L1 from <span class="hlt">ACE</span> (or future satellites) for predicting 'space weather' effects has also been demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840005024','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840005024"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> variations in the 60-100 year period range: A review</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Feynman, J.</p> <p>1983-01-01</p> <p>The evidence for and against the reality of a <span class="hlt">solar</span> <span class="hlt">wind</span> variation in the period range of 60-100 years is reexamined. Six data sets are reviewed; sunspot numbers, geomagnetic variations, two auroral data sets and two (14)C data sets. These data are proxies for several different aspects of the <span class="hlt">solar</span> <span class="hlt">wind</span> and the presence or absence of 60-100 year cyclic behavior in a particular data set does not necessarily imply the presence or absence of this variation in other sets. It was concluded that two different analyses of proxy data for a particular characteristic of the heliospheric <span class="hlt">solar</span> <span class="hlt">wind</span> yielded conflicting results. This conflict can be resolved only by future research. It is also definitely confirmed that proxy data for the <span class="hlt">solar</span> <span class="hlt">wind</span> in the ecliptic at 1 A.U. undergo a periodic variation with a period of approximately 87 years. The average amplitude and phase of this variation as seen in eleven cycles of proxy data are presented.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2621P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2621P"><span>BMSW - Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span> Monitor - three years in orbit: Status and prospects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prech, Lubomir; Zastenker, Georgy; Nemecek, Zdenek; Safrankova, Jana; Vaverka, Jakub; Cermak, Ivo; Chesalin, Lev S.; Gavrilova, Elena</p> <p></p> <p>Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span> plasma parameters directing the instrument to study of fast <span class="hlt">solar</span> <span class="hlt">wind</span> discontinuities including interplanetary shocks, a fast variability of proton and alpha particle parameters, and to study of <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM11B2312S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM11B2312S"><span>Vortex, ULF wave and Aurora Observation after <span class="hlt">Solar</span> <span class="hlt">Wind</span> Dynamic Pressure Change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shi, Q.</p> <p>2017-12-01</p> <p>Here we will summarize our recent study and show some new results on the Magnetosphere and Ionosphere Response to Dynamic Pressure Change/disturbances in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> and foreshock regions. We study the step function type <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure change (increase/decrease) interaction with the magnetosphere using THEMIS satellites at both dayside and nightside in different geocentric distances. Vortices generated by the dynamic pressure change passing along the magnetopause are found and compared with model predictions. ULF waves and vortices are excited in the dayside and nightside plasma sheet when dynamic pressure change hit the magnetotail. The related ionospheric responses, such as aurora and TCVs, are also investigated. We compare Global MHD simulations with the observations. We will also show some new results that dayside magnetospheric FLRs might be caused by foreshock structures.Shi, Q. Q. et al. (2013), THEMIS observations of ULF wave excitation in the nightside plasma sheet during sudden impulse events, J. Geophys. Res. Space Physics, 118, doi:10.1029/2012JA017984. Shi, Q. Q. et al. (2014), <span class="hlt">Solar</span> <span class="hlt">wind</span> pressure pulse-driven magnetospheric vortices and their global consequences, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019551. Tian, A.M. et al.(2016), Dayside magnetospheric and ionospheric responses to <span class="hlt">solar</span> <span class="hlt">wind</span> pressure increase: Multispacecraft and ground observations, J. Geophys. Res., 121, doi:10.1002/2016JA022459. Shen, X.C. et al.(2015), Magnetospheric ULF waves with increasing amplitude related to <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure changes: THEMIS observations, J. Geophys. Res., 120, doi:10.1002/2014JA020913Zhao, H. Y. et al. (2016), Magnetospheric vortices and their global effect after a <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure decrease, J. Geophys. Res. Space Physics, 121, doi:10.1002/2015JA021646. Shen, X. C., et al. (2017), Dayside magnetospheric ULF wave frequency modulated by a <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure negative impulse, J. Geophys. Res</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9105L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9105L"><span>Hall-MHD simulations of the magnetosphere-northward <span class="hlt">solar</span> <span class="hlt">wind</span> interface : the Kelvin-Helmholtz instability as an entry mechanism for the <span class="hlt">solar</span> <span class="hlt">wind</span> through mixing and reconnections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leroy, Matthieu; Keppens, Rony</p> <p>2016-04-01</p> <p>The transfer of matter from the <span class="hlt">solar-wind</span> to the Earth's magnetosphere during southward <span class="hlt">solar</span> <span class="hlt">wind</span> is mostly well understood but the processes governing the same phenomenon during northward <span class="hlt">solar</span> <span class="hlt">wind</span> remains to be fully apprehended. Numerous numerical studies have investigated the topic with many interesting results but most of these were considering two-dimensional situations with simplified magnetic configuration and often neglecting the inhomogeneities for the sake of clarity. Given the typical parameters at the magnetosphere-<span class="hlt">solar</span> <span class="hlt">wind</span> interface, the situation must be considered in the frame of Hall-MHD, due to the fact that the current layers widths and the gradient lengths can be in the order of the ion inertial length. As a consequence of Hall-MHD creating a third vector component from two planar ones, and also because magnetic perturbations can affect the field configuration at a distance in all directions and not only locally, three-dimensional treatment is necessary. In this spirit three-dimensional simulations of a configuration approaching the conditions leading to the development of Kelvin-Helmholtz instabilities at the flank of the magnetosphere during northward oriented <span class="hlt">solar-wind</span> are performed as means to study the entry of <span class="hlt">solar-wind</span> matter into Earth's magnetic field. In the scope of assessing the effect of the Hall-term in the physical processes, the simulations are also performed in the MHD frame. Furthermore the influence of the density and velocity jump through the shear layer on the rate of mass entering the magnetosphere is explored. Indeed, depending on the exact values of the physical quantities, the Kelvin-Helmholtz instability may have to compete with secondary instabilities and the non-linear phase may exhibit vortex merging and large-scale structures reorganisation, creating very different mixing layers, or generate different reconnection sites, locally and at a distance. These different configurations may have discernible signatures</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730006083','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730006083"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> photoplate study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scott, B. W.; Voorhies, H. G.</p> <p>1972-01-01</p> <p>An ion sensitive emulsion detection system has been considered for use in a cycloidal focusing mass spectrometer to measure the various atomic species which comprise the <span class="hlt">solar</span> plasma. The responses of Ilford Q2 and Kodak SC7 emulsions were measured with N(+) ions at 6 keV to 10 keV, He(++) ions at 750 eV to 2500 eV, and H(+) ions at 550 eV to 1400 eV. These ions have the approximate range of velocities (about 300-500 km/sec) encountered in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The work was carried out on a specially prepared magnetic sector mass analyzer. Characteristic response curves were generated, each one utilizing approximately 50 data points at three or more current densities. In addition to the ion response, measurements of the response of these emulsions to a photon flux simulating the visible portion of the <span class="hlt">solar</span> spectrum were made. The results obtained will be presented in detail and interpreted in relation to other data available for these emulsions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1026632','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1026632"><span>Microgrid Control Strategy Utlizing Thermal Energy Storage With Renewable <span class="hlt">Solar</span> And <span class="hlt">Wind</span> Power Generation</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-06-01</p> <p>13 Figure 6. Vertical Axis <span class="hlt">Wind</span> Turbines and Photovoltaic <span class="hlt">Solar</span> Panels ....................15 Figure 7. <span class="hlt">Solar</span> Sunny Boy Inverter...16 Figure 8. <span class="hlt">Wind</span> Turbine Inverters...1. Comparison of Energy Storage. Adapted from [16], [18], [19]. ................10 Table 2. DC Operating Voltage of <span class="hlt">Wind</span> Turbine Inverters</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5063966','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5063966"><span>Earth's magnetosphere and outer radiation belt under sub-Alfvénic <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lugaz, Noé; Farrugia, Charles J.; Huang, Chia-Lin; Winslow, Reka M.; Spence, Harlan E.; Schwadron, Nathan A.</p> <p>2016-01-01</p> <p>The interaction between Earth's magnetic field and the <span class="hlt">solar</span> <span class="hlt">wind</span> results in the formation of a collisionless bow shock 60,000–100,000 km upstream of our planet, as long as the <span class="hlt">solar</span> <span class="hlt">wind</span> fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the <span class="hlt">solar</span> <span class="hlt">wind</span> 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 <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling which is unusual for planets in our <span class="hlt">solar</span> system but may be common for close-in extrasolar planets. PMID:27694887</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38..419S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38..419S"><span>Interaction between <span class="hlt">solar</span> <span class="hlt">wind</span> and lunar magnetic anomalies observed by MAP-PACE on Kaguya</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Yoshifumi; Yokota, Shoichiro; Tanaka, Takaaki; Asamura, Kazushi; Nishino, Masaki N.; Yamamoto, Tadateru I.; Tsunakawa, Hideo</p> <p></p> <p>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 <span class="hlt">solar</span> <span class="hlt">wind</span> from penetrating into the magnetosphere, <span class="hlt">solar</span> <span class="hlt">wind</span> 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, <span class="hlt">solar</span> <span class="hlt">wind</span> ions reflected by magnetic anomalies were observed. These ions had much higher flux than the <span class="hlt">solar</span> <span class="hlt">wind</span> protons scattered at the lunar surface. The magnetically reflected ions had nearly the same energy as the incident <span class="hlt">solar</span> <span class="hlt">wind</span> ions while the <span class="hlt">solar</span> <span class="hlt">wind</span> protons scattered at the lunar surface had slightly lower energy than the incident <span class="hlt">solar</span> <span class="hlt">wind</span> ions. At 100km altitude, when the reflected ions</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060036154&hterms=dependency&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddependency','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060036154&hterms=dependency&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddependency"><span>(abstract) Ulysses <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Temperatures: Radial, Latitudinal, and Dynamical Dependencies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, B. E.; Smith, E. J.; Gosling, J. T.; McComas, D. J.; Balogh, A.</p> <p>1996-01-01</p> <p>Observations of the Ulysses SWOOPS plasma experiment are used to determine the dependencies of <span class="hlt">solar</span> <span class="hlt">wind</span> ion temperatures upon radial distance, speed, and other parameters, and to estimate <span class="hlt">solar</span> <span class="hlt">wind</span> heating. Comparisons with three dimensional temperature estimates determined from the ion spectra by a least squares fitting program will be provided (only small samples of data have been reduced with this program).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820042725&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWind%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820042725&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWind%2Benergy"><span><span class="hlt">Solar</span> <span class="hlt">wind</span> energy transfer through the magnetopause of an open magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lee, L. C.; Roederer, J. G.</p> <p>1982-01-01</p> <p>An expression is derived for the total power, transferred from the <span class="hlt">solar</span> <span class="hlt">wind</span> to an open magnetosphere, which consists of the electromagnetic energy rate and the particle kinetic energy rate. The total rate of energy transferred from the <span class="hlt">solar</span> <span class="hlt">wind</span> to an open magnetosphere mainly consists of kinetic energy, and the kinetic energy flux is carried by particles, penetrating from the <span class="hlt">solar</span> <span class="hlt">wind</span> into the magnetosphere, which may contribute to the observed flow in the plasma mantle and which will eventually be convected slowly toward the plasma sheet by the electric field as they flow down the tail. While the electromagnetic energy rate controls the near-earth magnetospheric activity, the kinetic energy rate should dominate the dynamics of the distant magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015244','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015244"><span>Modeling <span class="hlt">Solar-Wind</span> Heavy-Ions' Potential Sputtering of Lunar KREEP Surface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barghouty, A. F.; Meyer, F. W.; Harris, R. P.; Adams, J. H., Jr.</p> <p>2012-01-01</p> <p>Recent laboratory data suggest that potential sputtering may be an important weathering mechanism that can affect the composition of both the lunar surface and its tenuous exosphere; its role and implications, however, remain unclear. Using a relatively simple kinetic model, we will demonstrate that <span class="hlt">solar-wind</span> heavy ions induced sputtering of KREEP surfaces is critical in establishing the timescale of the overall <span class="hlt">solar-wind</span> sputtering process of the lunar surface. We will also also show that potential sputtering leads to a more pronounced and significant differentiation between depleted and enriched surface elements. We briefly discuss the impacts of enhanced sputtering on the composition of the regolith and the exosphere, as well as of <span class="hlt">solar-wind</span> sputtering as a source of hydrogen and water on the moon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19960021350&hterms=orbiting+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dorbiting%2Bwind','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19960021350&hterms=orbiting+wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dorbiting%2Bwind"><span>Features of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration according to radio occultation data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Efimov, A. I.</p> <p>1995-01-01</p> <p>In addressing one of the fundamental problems in <span class="hlt">solar</span> physics establishing the mechanism(s) responsible for the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration and the corona heating - it is essential to have a reliable knowledge of the heliocentric radial dependence of the <span class="hlt">solar</span> <span class="hlt">wind</span> properties. Adequate data are available for small <span class="hlt">solar</span> distances R less than 4 R(<span class="hlt">solar</span> mass) from coronal white light and EUV observations and at distances R greater than 60 R(<span class="hlt">solar</span> mass) from in situ measurements. One of the few methods available to fill in the gap between these boundaries is the radio scintillation technique. Taking the example of the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity, the most reliable such measurements are obtained when phase fluctuation observations of scattered radio waves, which are not susceptible to saturation effects, are recorded at two or more widely-spaced ground stations. Two extensive observation campaigns of this type were carried out with the Venus-orbiting satellites Venera 10 in 1976 and Venera 15/16 in 1984. The observations were performed over the course of three months near superior conjunction at <span class="hlt">solar</span> offset distances R approximately 6-80 R(<span class="hlt">solar</span> mass). The main results from the subsequent analysis of these data are: (1) velocities vary between 250 and 380 km s(exp -1) for R greater than 20 R(<span class="hlt">solar</span> mass), agreeing with similar measurements using natural sources (IPS); (2) velocities derived from two-station phase fluctuation observations varv between 70 and 120 km s(exp -1) for R less than 12 R(<span class="hlt">solar</span> mass), i.e. values substantially lower than those derived from conventional IPS data; and (3) it is suggested that the different velocity profiles derived from the two data sets at small R may be due to the effects of magnetosonic and Alfvenic waves on radio wave scattering. Further analysis of additional radio sounding data should help resolve the apparent discrepancy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080030143&hterms=negev+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnegev%2Bradiation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080030143&hterms=negev+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnegev%2Bradiation"><span>Simulations of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvyn L.; Usmanov, A. V.; Roberts, D. A.</p> <p>2008-01-01</p> <p>Recently we have restructured our approach to simulating magnetohydrodynamic (MHD) turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span>. Previously, we had defined a 'virtual' heliosphere that contained, for example, a tilted rotating current sheet, microstreams, quasi-two-dimensional fluctuations as well as Alfven waves. In this new version of the code, we use the global, time-stationary, WKB Alfven wave-driven <span class="hlt">solar</span> <span class="hlt">wind</span> model developed by Usmanov and described in Usmanov and Goldstein [2003] to define the initial state of the system. Consequently, current sheets, and fast and slow streams are computed self-consistently from an inner, photospheric, boundary. To this steady-state configuration, we add fluctuations close to, but above, the surface where the flow become super-Alfvenic. The time-dependent MHD equations are then solved using a semi-discrete third-order Central Weighted Essentially Non-Oscillatory (CWENO) numerical scheme. The computational domain now includes the entire sphere; the geometrical singularity at the poles is removed using the multiple grid approach described in Usmanov [1996]. Wave packets are introduced at the inner boundary such as to satisfy Faraday's Law [Yeh and Dryer, 1985] and their nonlinear evolution are followed in time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AAS...21640521A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AAS...21640521A"><span>A Model for the Sources of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antiochos, Spiro K.; Mikic, Z.; Lionello, R.; Titov, V.; Linker, J.</p> <p>2010-05-01</p> <p>Models for the origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> must account for two seemingly contradictory observations: The slow <span class="hlt">wind</span> has the composition of the closed-field corona, implying that it originates at the open-closed field boundary layer, but it also has large angular width, up to 40 degrees. We propose a model that can explain both observations. The key idea is that the source of the slow <span class="hlt">wind</span> at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We calculate with high numerical resolution, the quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetic field for a Carrington rotation centered about the August 1, 2008 total <span class="hlt">solar</span> eclipse. Our numerical results demonstrate that, at least for this time period, a web of separatrices (S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow <span class="hlt">wind</span>. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere, and propose further tests of the model. This work was supported, in part, by the NASA HTP, TR&T and SR&T programs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/re-powering/solar-and-wind-site-screening-decision-trees','PESTICIDES'); return false;" href="https://www.epa.gov/re-powering/solar-and-wind-site-screening-decision-trees"><span><span class="hlt">Solar</span> and <span class="hlt">Wind</span> Site Screening Decision Trees</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>EPA and NREL created a decision tree to guide state and local governments and other stakeholders through a process for screening sites for their suitability for future redevelopment with <span class="hlt">solar</span> photovoltaic (PV) energy and <span class="hlt">wind</span> energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P12A..07C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P12A..07C"><span>Dependence of Photochemical Escape of Oxygen at Mars on <span class="hlt">Solar</span> Radiation and <span class="hlt">Solar</span> <span class="hlt">Wind</span> Interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cravens, T.; Rahmati, A.; Lillis, R. J.; Fox, J. L.; Bougher, S. W.; Jakosky, B. M.</p> <p>2016-12-01</p> <p>The evolution of the atmosphere of Mars and the loss of volatiles over the life of the <span class="hlt">solar</span> system is a key topic in planetary science. An important loss process in the ionosphere is photochemical escape. In particular, dissociative recombination of O2+ ions (the major ion species) produces fast oxygen atoms, some of which can escape from the planet. Several theoretical models have been constructed over the years to study hot oxygen and its escape from Mars. These model have a number of uncertainties, particularly for the elastic cross sections of O collisions with target neutral species. Recently, the Mars Atmosphere and Volatile Evolution Mission (MAVEN) mission has been rapidly improving our understanding of the upper atmosphere and ionosphere of Mars and its interaction with the external environment (e.g., the <span class="hlt">solar</span> <span class="hlt">wind</span>). The purpose of the current paper is to take a simple analytical approach to the oxygen escape problem in order to: (1) study the role that <span class="hlt">solar</span> flux and <span class="hlt">solar</span> <span class="hlt">wind</span> variations have on escape and (2) isolate the effects of uncertainties in oxygen cross sections on the derived oxygen escape rates. Not surprisingly, we find, in agreement with more elaborate numerical models, that the escape flux is directly proportional to the incident <span class="hlt">solar</span> extreme ultraviolet irradiance and is inversely proportional to the backscatter elastic cross section. The role for atmospheric loss that ion transport plays in the topside ionosphere and how the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction drives this will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026625','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026625"><span>Numerical Simulations of Mass Loading in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Interaction with Venus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Murawski, K.; Steinolfson, R. S.</p> <p>1996-01-01</p> <p>Numerical simulations are performed in the framework of nonlinear two-dimensional magnetohydrodynamics to investigate the influence of mass loading on the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Venus. The principal physical features of the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the atmosphere of Venus are presented. The formation of the bow shock, the magnetic barrier, and the magnetotail are some typical features of the interaction. The deceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span> due to the mass loading near Venus is an additional feature. The effect of the mass loading is to push the shock farther outward from the planet. The influence of different values of the magnetic field strength on plasma evolution is considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020022191&hterms=fall&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D80%26Ntt%3Dfall','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020022191&hterms=fall&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D80%26Ntt%3Dfall"><span>Low-Latitude <span class="hlt">Solar</span> <span class="hlt">Wind</span> During the Fall 1998 SOHO-Ulysses Quadrature</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Poletto, G.; Suess, Steven T.; Biesecker, D.; Esser, R.; Gloeckler, G.; Zurbuchen, T.; Whitaker, Ann F. (Technical Monitor)</p> <p>2001-01-01</p> <p>The Fall 1998 <span class="hlt">SOlar</span>-Heliospheric Observatory (SOHO) - Ulysses quadrature occurred when Ulysses was at 5.2 AU, 17.4 deg South of the equator, and off the West line of the Sun. SOHO coronal observations, at heliocentric distances of a few <span class="hlt">solar</span> radii, showed that the line through the <span class="hlt">solar</span> center and Ulysses crossed, over the first days of observations, a dark, weakly emitting area and through the northern edge of a streamer complex during the second half of the quadrature campaign. Ulysses in situ observations showed this transition to correspond to a decrease from higher speed <span class="hlt">wind</span> typical of coronal hole flow to low speed <span class="hlt">wind</span>. Physical parameters (density, temperature, flow speed) of the low latitude coronal plasma sampled over the campaign are determined using constraints from what is the same plasma measured later in situ and simulating the intensities of the Hydrogen Lyman-alpha and OVI 1032 and 1037 Angstrom lines, measured by the Ultra Violet Coronagraph Spectrometer (UVCS) on SOHO. The densities, temperatures and outflow speed are compared with the same characteristic flow parameters for high-latitude fast <span class="hlt">wind</span> streams and typical slow <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22342008-coherent-structure-solar-wind-sup-sup-ionic-composition-data-during-quiet-sun-conditions','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22342008-coherent-structure-solar-wind-sup-sup-ionic-composition-data-during-quiet-sun-conditions"><span>Coherent structure in <span class="hlt">solar</span> <span class="hlt">wind</span> C{sup 6+}/C{sup 4+} ionic composition data during the quiet-sun conditions of 2008</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Edmondson, J. K.; Lepri, S. T.; Zurbuchen, T. H.</p> <p>2013-11-20</p> <p>This analysis offers evidence of characteristic scale sizes in <span class="hlt">solar</span> <span class="hlt">wind</span> charge state data measured in situ for 13 quiet-Sun Carrington rotations in 2008. Using a previously established novel methodology, we analyze the wavelet power spectrum of the charge state ratio C{sup 6+}/C{sup 4+} measured in situ by <span class="hlt">ACE</span>/SWICS for 2 hr and 12 minute cadence. We construct a statistical significance level in the wavelet power spectrum to quantify the interference effects arising from filling missing data in the time series, allowing extraction of significant power from the measured data to a resolution of 24 minutes. We analyze each waveletmore » power spectrum for transient coherency and global periodicities resulting from the superposition of repeating coherent structures. From the significant wavelet power spectra, we find evidence for a general upper limit on individual transient coherency of ∼10 days. We find evidence for a set of global periodicities between 4-5 hr and 35-45 days. We find evidence for the distribution of individual transient coherency scales consisting of two distinct populations. Below the ∼2 day timescale, the distribution is reasonably approximated by an inverse power law, whereas for scales ≳2 days, the distribution levels off, showing discrete peaks at common coherency scales. In addition, by organizing the transient coherency scale distributions by <span class="hlt">wind</span> type, we find that these larger, common coherency scales are more prevalent and well defined in coronal hole <span class="hlt">wind</span>. Finally, we discuss the implications of our results for current theories of <span class="hlt">solar</span> <span class="hlt">wind</span> generation and describe future work for determining the relationship between the coherent structures in our ionic composition data and the structure of the coronal magnetic field.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030032419&hterms=corona&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcorona','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030032419&hterms=corona&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcorona"><span>Three-Dimensional MHD Modeling of The <span class="hlt">Solar</span> Corona and <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Comparison with The Wang-Sheeley Model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Usmanov, A. V.; Goldstein, M. L.</p> <p>2003-01-01</p> <p>We present simulation results from a tilted-dipole steady-state MHD model of the <span class="hlt">solar</span> corona and <span class="hlt">solar</span> <span class="hlt">wind</span> and compare the output from our model with the Wang-Sheeley model which relates the divergence rate of magnetic flux tubes near the Sun (inferred from <span class="hlt">solar</span> magnetograms) to the <span class="hlt">solar</span> <span class="hlt">wind</span> speed observed near Earth and at Ulysses. The boundary conditions in our model specified at the coronal base and our simulation region extends out to 10 AU. We assumed that a flux of Alfven waves with amplitude of 35 km per second emanates from the Sun and provides additional heating and acceleration for the coronal outflow in the open field regions. The waves are treated in the WKB approximation. The incorporation of wave acceleration allows us to reproduce the fast <span class="hlt">wind</span> measurements obtained by Ulysses, while preserving reasonable agreement with plasma densities typically found at the coronal base. We find that our simulation results agree well with Wang and Sheeley's empirical model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006ihy..workE.113J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006ihy..workE.113J"><span>Role of Ambient <span class="hlt">Solar</span> <span class="hlt">Wind</span> Conditions in CME evolution (P21)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jadav, R.; Jadeja, A. K.; Iyer, K. N.</p> <p>2006-11-01</p> <p>ipsraj@yahoo.com <span class="hlt">Solar</span> events are mainly responsible for producing storms at the Earth. Coronal Mass Ejection (CME) is a major cause for this. In this paper, Coronal Mass Ejections occurred during 1998-2004 are studied. Ambient <span class="hlt">solar</span> <span class="hlt">wind</span> does play some role in determining the effect of a CME. The effects produced at the Earth during the period 1999 2004 are considered and an attempt has been made to understand the role of ambient <span class="hlt">solar</span> <span class="hlt">wind</span>. This is to draw some conclusion about how some of the events become geo- effective.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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