Search NASA⌕ Search

SEARCH · Search NASA

Results for “SOLAR PLASMA”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Solar Array Module Plasma Interaction Experiment (SAMPIE)

The objective of the Solar Array Module Plasma Interaction Experiment (SAMPIE) is to investigate, by means of a shuttle-based flight experiment and relevant ground-based testing, the arcing and current collection behavior of materials and geometries likely to be exposed to the LEO plasma on high-voltage space power systems, in order to minimize adverse environmental interactions. An overview of the SAMPIE program is presented in outline and graphical form.

Ferguson, Dale C.↗
NASA NTRS2010

Opportunities for Utilizing the International Space Station for Studies of F2- Region Plasma Science and High Voltage Solar Array Interactions with the Plasma Environment

The near circular, 51.6deg inclination orbit of the International Space Station (ISS) is maintained within an altitude range of approximately 300 km to 400 km providing an ideal platform for conducting in-situ studies of space weather effects on the mid and low-latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) is a suite of instruments installed on the ISS in August 2006 which includes a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). The primary purpose for deploying the FPMU is to characterize ambient plasma temperatures and densities in which the ISS operates and to obtain measurements of the ISS potential relative to the space plasma environment for use in characterizing and mitigating spacecraft charging hazards to the vehicle and crew. In addition to the engineering goals, data from the FPMU instrument package is available for collaborative multi-satellite and ground based instrument studies of the F-region ionosphere during both quiet and disturbed periods. Finally, the FPMU measurements supported by ISS engineering telemetry data provides a unique opportunity to investigate interactions of the ISS high voltage (160 volt) solar array system with the plasma environment. This presentation will provide examples of FPMU measurements along the ISS orbit including night-time equatorial plasma density depletions sampled near the peak electron density in the F2-region ionosphere, charging phenomenon due to interaction of the ISS solar arrays with the plasma environment, and modification of ISS charging due to visiting vehicles demonstrating the capabilities of the FPMU probes for monitoring mid and low latitude plasma processes as well as vehicle interactions with the plasma environment.

Minow, Joseph I.↗
NASA NTRS1992

Active region studies with coordinated SOHO, microwave, and magnetograph observations

The scientific justification for an observing campaign to study the quantitative magnetic and plasma properties of coronal loops in active regions is presented. The SOHO (Solar and Heliospheric Observatory) instruments of primary relevance are CDS (Coronal Diagnostic Spectrometer), EIT, SUMER (Solar Ultraviolet Measurement of Emitted Radiation), and MDI. The primary ground based instruments would be the VLA (Very Large Array), the Owens Valley Radio Observatory, and vector and longitudinal field magnetographs. Similar campaigns have successfully been carried out with the Solar Maximum Mission x-ray polychromator and the Soft X-ray Imaging Sounding Rocket Payload (CoMStOC '87), the Goddard Solar EUV Rocket Telescope and Spectrograph, the Lockheed Solar Plasma Diagnostics Experiment rocket payload, and the Soft X-ray Telescope in Yohkoh (CoMStoc '92). The scientific payoff from such a campaign is discussed in light of the results from these previous campaigns.

Holman, Gordon D.↗
NASA NTRS1979

Solar flares

The present paper deals with explosions in a magnetized solar plasma, known as flares, whose effects are seen throughout the electromagnetic spectrum, from gamma-rays through the visible and to the radio band. The diverse phenomena associated with flares are discussed, along with the physical mechanisms that have been advanced to explain them. The impact of solar flare research on the development of plasma physics and magnetohydrodynamics is noted. The rapid development of solar flare research during the past 20 years, owing to the availability of high-resolution images, detailed magnetic field measurements, and improved spectral data, is illustrated.

Rust, D. M.↗
NASA NTRS1974

Lunar interactions: Abstracts of papers presented at the Conference on Interactions of the Interplanetary Plasma with the Modern and Ancient Moon

Reviewed are the active mechanisms relating the moon to its environment and the linkage between these mechanisms and their records in the lunar sample and geophysical data. Topics: (1) large scale plasma interactions with the moon and non-magnetic planets; (2) ancient and present day lunar surface magnetic and electric fields; (3) dynamics and evolution of the lunar atmosphere; (4) evolution of the solar plasma; (5) lunar record of solar radiations; (6) non-meteoritic and meteoritic disturbance and transport of lunar surface materials; and (7) future lunar exploration.

Criswell, D. R.↗
NASA NTRS1963

GEOMAGNETIC DISTURBANCES

Importance of the magnetosphere in interpretation of geomagnetic disturbances, and the role of solar winds, solar plasma stream and sudden commencements

GEOMAGNETIC STORM↗
NASA NTRS1972

Comparison of deep space and near-earth observations of plasma turbulence at solar wind discontinuities

Simultaneous observations of plasma waves from the electric field instruments on Pioneer 9 and OGO 5 are used to illustrate the difference between near-earth and deep space conditions. It is shown that the experimental study of true interplanetary wave-particle interactions is difficult to carry out from an earth orbiter because the earth provides significant fluxes of nonthermal particles that generate intense plasma turbulence in the upstream region.

Scarf, F. L.↗
NASA NTRS1979

Effects of plasma sheath on solar power satellite array

The structure of the plasma sheath and equilibrium voltage distribution of a high-power solar array governs various kinds of plasma-interaction phenomena and array losses. Sheath effects of a linearly-connected array are investigated for GEO. Although the array may be large, the thin-sheath-limit analysis may be invalid, necessitating numerical methods. Three-dimensional computer calculations show that potential barriers and over-lapping sheaths can occur, i.e., structures not predictable under the thin-sheath-limit analysis, but nevertheless controlling the distribution of plasma currents impacting on the array.

Parker, L. W.↗
NASA NTRS2012

DC and Structured Electric Fields Observed on the C/NOFS Satellite and Their Association with Longitude, Plasma Density, and Solar Activity

Observations of DC electric fields and associated E x B plasma drifts gathered by the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite are presented. We show statistical averages of the vector fields and resulting E x B plasma flows for the first three years of operations as a function of season, longitude, local time, and Fl 0.7 conditions. Magnetic field data from the VEFI science magnetometer are used to compute the plasma flows. Although typically displaying eastward and outward-directed fields during the day and westward and downward-directed fields at night, the data from DC electric field detector often reveal variations from this pattern that depend on longitude, solar activity, and plasma density. Clear "wave-4" tidal effects in both electric field components have been detected and will be presented. Zonal plasma drifts show a marked variation with solar activity and may be used as a proxy for neutral winds at night. Evidence for pre-reversal enhancements in the meridional drifts that depend on solar activity is present for some longitudes, and are corroborated by clear evidence in the plasma density data that the spacecraft journeyed below the F-peak during evenings when the rise in the ionosphere is most pronounced. In addition to DC electric fields, the data reveal considerable electric field structures at large scales (approx 100's of km) that are usually confined to the nightside. Although such electric field structures are typically associated with plasma density depletions and structures, what is surprising is the number of cases in which large amplitude, structured DC electric fields are observed without a significant plasma density counterpart structure, including their appearance at times when the ambient plasma density appears relatively quiescent. We investigate the mapping of structured electric fields along magnetic field lines from distant locations and consider tropospheric thunderstorm sources to explain some of the observations. The dependence of the structuring on season and solar activity will be reported and discussed.

Pfaff, Robert↗
NASA NTRS1964

Interplanetary magnetic fields.

Interplanetary magnetic fields discussing effects of solar plasma on origin, properties, irregularities and disturbances

SOLAR WIND↗
NASA NTRS1973

Exploring Jupiter, Saturn and their satellites.

By exploring the outer solar system, it is possible to go back in time and sample the conditions and the energetics of primitive solar nebula from which the sun and the planets are believed to have condensed. With the aid of particle detectors and magnetometers on a spacecraft going to the outer planets, it will be possible to study the gradients of the solar plasma, cosmic rays, and the interplanetary magnetic field. A number of questions regarding the outer solar system are examined, giving attention to problems of the origin of excess energy in the case of Jupiter, Jupiter radio emissions, problems of planetary meteorology, the rings of Saturn, and the planetary satellites. Critical in situ measurements are discussed together with exploratory missions, spacecraft characteristics, and aspects of preliminary mission design.

Rasool, S. I.↗
NASA NTRS1978

A search for space energy alternatives

This paper takes a look at a number of schemes for converting radiant energy in space to useful energy for man. These schemes are possible alternatives to the currently most studied solar power satellite concept. Possible primary collection and conversion devices discussed include the space particle flux devices, solar windmills, photovoltaic devices, photochemical cells, photoemissive converters, heat engines, dielectric energy conversion, electrostatic generators, plasma solar collectors, and thermionic schemes. Transmission devices reviewed include lasers and masers.

Gilbreath, W. P.↗
NASA NTRS1994

The allowed lines of O IV near 1340 A in high electron density solar flares

Intersystem lines of O IV near 1400 A have long been used as electron density diagnostics for solar plasmas at temperatures of around 160,000 K. In addition, however, several allowed lines of O IV near 1340 A should become visible in conditions of high plasma electron number density (greater than 10(exp 12)/cu cm), such as during a solar flare. We present observations of the 1340 A and 1400 A regions of the solar spectrum for two solar flares, obtained by the SO82B spectrograph on board Skylab. We examine three candidate lines for allowed O IV in the flare spectra which occur at the correct wavelengths, but show that two of these are actually blends dominated by resonantly excited molecular lines of H2. The third candidate line, at 1343.51 A, we identify as the O IV allowd line. We present the density and temperature sensitivity of the ratio of allowed and intersystem O IV lines R = I(1343.51 A)/I(1407.39 A). The 1343.51 A line is clearly present in the first solar flare spectrum, and the ratio value implies an electron density of log N(sub e) = 12.6. The second flare has a much weaker 1343.51 A profile, but again the ratio value implies a high electron density. Both these electron density values are in good agreement with estimates for each flare from independent diagnostic ratios. The simple presence alone of a clearly observed O IV 1343.51 A emission line implies an electron density greater than 10(exp 12)/cu cm.

Cook, J. W.↗
NASA NTRS2001

Solar Collector With Image-Forming Mirror Cavity to Irradiate Small Central Volume

A unique solar thermal chamber has been designed and fabricated to produce the maximum concentration of solar energy and higher temperature possible. Its primary purpose was for solar plasma propulsion experiments and related material specimen testing above 3000 K. The design not only maximized solar concentration, but also, minimized infrared heat loss. This paper provides the underlying theory and operation of the chamber and initial optical correlation to the actual fabricated hardware. The chamber is placed at the focal point of an existing primary concentrator with a 2.74 m (9 ft) focal length. A quartz lens focuses a small sun image at the inlet hole of the mirrored cavity. The lens focuses two image planes at prescribed positions; the sun at the cavity's entrance hole and the primary concentrator at the junction plane of two surfaces that form the cavity chamber. The back half is an ellipsoid reflector that produces a 1.27 cm diameter final sun image. The image is "suspended in space," 7.1 cm away from the nearest cavity surface, to minimize thermal and contaminate damage to the mirror surfaces. A hemisphere mirror makes up the front chamber and has its center of curvature at the target image, where rays leaving the target are reflected back upon themselves, minimizing radiation losses.

Buchele, Don↗
NASA NTRS1994

The determination of electron densities in the solar atmosphere from the 1718.56 A/1486.51 A emission-line ratio in N IV

The theoretical electron density sensitive emission-line ratio R = I(1718.56 a)/I(1486.51 A) in N IV is presented for a range of N(sub e)(approximately equals 10(exp 10) - 10(exp 12)/cu cm) applicable to higher density solar plasmas, such as active regions. A comparison of these calculations with the observed values of R of several solar features obtained with the Naval Research Laboratory's S082B spectrograph on board Skylab reveals general agreement between theory and observation at pointings just above the limb, where line blends with N IV 1718.56 A should be insignificant, which provides experimental support for the accuracy of the line ratio calculations.

Keenan, F. P.↗
NASA NTRS1984

Initial results from the repaired Solar Maximum Mission and future prospects

Goals of the recently repaired Solar Maximum Mission Observatory are outlined, including continued emphasis on diagnosing impulsive phase of flares, studies of prominence and coronal plasmas, solar cycle variations of flares, the corona and solar irradiance, and comets. Some preliminary observations taken after the repair are shown, particularly of the X13 flare of April 1984.

Woodgate, B. E.↗
NASA NTRS1974

Lunar electrical conductivity, permeability,and temperature from Apollo magnetometer experiments

Magnetometers were deployed at four Apollo sites on the moon to measure remanent and induced lunar magnetic fields. Measurements from this network of instruments were used to calculate the electrical conductivity, temperature, magnetic permeability, and iron abundance of the lunar interior. Global lunar fields due to eddy currents, induced in the lunar interior by magnetic transients, were analyzed to calculate and electrical conductivity profile for the moon, and those profiles were used to calculate the lunar temperature for an assumed lunar material of olivine. Simultaneous measurements by magnetometers on the lunar surface and in orbit around the moon were use to construct a whole-moon hysteresis curve, from which the global lunar magnetic permeability is determined. Total iron abundance (sum of iron in the ferromagnetic and paramagnetic states) was calculated for two assumed compositional models of the lunar interior. Other lunar models with an iron core and with a shallow iron-rich layer also discussed in light of the measured global lunar permeability. Simultaneous magnetic field and solar plasma pressure measurements show that the remanent fields at the Apollo 12 and 16 sites interact with, and are compressed by, the solar wind. Velocities and thicknesses of the earth's magnetopause and bow shock were also estimated from simultaneous magnetometer measurements.

Dyal, P.↗