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Results for “solar-terrestrial interactions”

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.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Solar-terrestrial interactions

The effects of solar radiation on man's environment are discussed. It is solar radiation that is the basic energy source driving the circulations of the earth's atmosphere and oceans. Solar radiation is responsible for the ionization of the earth's upper atmosphere to form the ionosphere, which is important to our understanding of the magnetosphere and its interaction with the solar wind. The solar wind, which is the continuous (but not steady) flow of the sun's coronal plasma and magnetic field into interplanetary space, plays both an active and passive role in its interaction with the earth's environment.

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NASA NTRS1982

Turbulence and wave particle interactions in solar-terrestrial plasmas

Theoretical modelling of two dimensional compressible convection in the Sun shows that convective flows can extend over many pressure scale heights without the nonlinear motions becoming supersonic, and that compressional work arising from pressure fluctuations can be comparable to that by buoyancy forces. These results are contrary to what was supposed in prevailing mixing length models for solar convection, and they imply a much greater degree of organized flow extending over the full depth of the convection zone. The nonlinear penetration of motions into the stable region below the convection zone was emphasized. These compressible flows are dominated by downward directed plumes in the unstable zone. Their strong penetration into the region of stable stratification below excites a broad spectrum of internal gravity waves there, and these in turn feed back upon the convection in the unstable zone to produce a rich time dependence.

Dulk, G. A.↗
NASA NTRS1985

Turbulence and wave particle interactions in solar-terrestrial plasmas

Activities in the following study areas are reported: (1) particle and wave processes in solar flares; (2) solar convection zone turbulence; and (3) solar radiation emission. To investigate the amplification of cyclotron maser radiation in solar flares, a radio frequency. (RF) heating model was developed for the corona surrounding the energy release site. Then nonlinear simulations of compressible convection display prominent penetration by plumes into regions of stable stratification at the base of the solar convection zone, leading to the excitation of internal gravity waves there. Lastly, linear saturation of electron-beam-driven Langmuir waves by ambient density fluctuations, nonlinear saturation by strong turbulence processes, and radiation emission mechanisms are examined. An additional section discusses solar magnetic fields and hydromagnetic waves in inhomogeneous media, and the effect of magnetic fields on stellar oscillation.

Dulk, G. A.↗
NASA NTRS1977

Characteristics of a solar-terrestrial observatory

The operation of the Solar-Terrestrial Observatory is outlined. It will monitor the diurnal, solar rotational, seasonal, and solar cycle variation to aid the understanding of the solar-terrestrial interaction mechanism. The continuous measurements at a space station include in-situ remote sensing, and active probing techniques.

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NASA NTRS1978

Statement of Doctor Noel Hinners, Associate Administrator for Space Sciences, National Aeronautics and Space Administration

Leadership in space exploration is an important part of the nation's prestige. There is a large science component in what are called applications and visa versa. Space science can provide the basis for some of the steps and bridges to possibilities envisioned for the year 2000 and forward. Both chemistry and physics are basis priorities in NASA missions and research activities. Current programs are concerned with developing the capability to put more weight in space, to provide for revisiting facilities such as the space telescope and provide for on-orbit repair or retrieval. Programs requiring the construction of facilities in space require higher levels of energy than those currently available. The prospective development of low-thrust propulsion in the 1980's will reduce transportation time. Data from Skylab and that to be obtained from Spacelab as well as investigations of solar-terrestrial interactions will benefit space tourists and inhabitants.

Hinners, N.↗
NASA NTRS1983

Solar and heliospheric physics space missions for the 1980's

Proposed space missions or observing facilities for the late 1980s and early 1990s that would enable research on specific problems in solar and heliospheric physics are reviewed. For studies of the sun's interior, mission possibilities include the Solar Internal Dynamics Mission (SIDM) or the Solar Beacon to provide continuous monitoring of solar oscillations, and the Starprobe grazing encounter flyby. Visible surface atmospheres of the sun may be studied by the repair of the Solar Maximum Mission, and an Advanced Solar Observatory making observations from the X-ray to the IR. Possible missions investigating the inner corona would involve the proposed Solar Interplanetary Satellite (SIS), which would complement the single-spacecraft International Solar Polar Mission, the Solar Corona Diagnostics Mission (SCDM), and Starprobe. The SIS, Interplanetary Physics Laboratory and SCDM missions would also permit measurement of the solar wind. Experiments of opportunity based on the SMM, SIS, SCDM and SIDM projects may be used for studies of solar-terrestrial interactions, together with dedicated programs such as the Solar Terrestrial Observatory.

Bohlin, J. D.↗
NASA NTRS1984

Solar Terrestrial Physics: Present and Future

The following topics relating to solar-terrestrial interactions are considered: (1) reconnection of magnetic fields; (2) particle acceleration; (3) solar magnetic flux; (4) magnetohydrodynamic waves and turbulence in the Sun and interplanetary medium; (5) coupling of the solar wind to the magnetosphere; (6) coronal transients; (7) the connection between the magnetosphere and ionosphere; (8) substorms in the magnetosphere; (9) solar flares and the solar terrestrial environment; (10) shock waves in the solar terrestrial environment; (11) plasma transport and convection at high latitudes; and (12) high latitude ionospheric structure.

Butler, D. M.↗
NASA NTRS1983

A climate hypothesis describing the solar-terrestrial system as a frequency domain with specific response characteristics

A climatological model of the earth-sun system based on an analogy to Planck's law of quantum mechanics is developed. The role of the diabatically important trace gases O3, H2O, and CO2 in the complex processes by which solar cycles affect tropospheric-stratospheric stability, and the value of the resonance concept in understanding these phenomena are examined. Consideration is given to climate complexity and the Laplace transform of the solar cycle, direct versus indirect solar signals, intense convection in coupled dynamics, the basic mechanisms of solar-terrestrial interaction, and the Planck's-law analog. The quantum approach, taking complexity into account, is shown to be more appropriate for evaluating the effects of anthropogenic modifications of the atmosphere (e.,g., increasing CO2) than the linear bulk-heating approaches usually applied.

Paine, D. A.↗
NASA NTRS1984

Solar-terrestrial research opportunities - A look to the future

Recent and proposed research programs and their impact on the understanding of solar-terrestrial interactions, the processes driving solar activity, and the propagation of the solar wind are outlined. The magnetospheres of the earth and major planets have been mapped and their interactions with the solar wind modeled. MHD activity has been identified as the driving force for stellar surface activity, and Pioneer data are permitting a mapping of the outer areas of the heliosphere. Further studies are required to understand solar magnetic field-earth magnetosphere, ionosphere-atmosphere interactions, the effects of solar heating on earth atmosphere ozone levels, and the effects of solar transient events on the earth atmosphere. The initiation of an International Geosphere-Biosphere Program is now under study and several satellites for solar-terrestrial research are under development as cooperative efforts among the U.S., Japanese, and European agencies.

Intriligator, D. S.↗
NASA NTRS1984

High Latitude Ionospheric Structure

The Earth's ionosphere is an important element in solar-terrestrial energy transfer processes. As a major terrestrial sink for many solar and magnetospheric events, the ionosphere has characteristic features that are traced to such seemingly remote phenomena as solar flares, radiation belt wave-particle interactions and magnetospheric substorms. In considering the multiple of solar-terrestrial plasma interactions, it is important to recognize that the high-latitude ionosphere is not altogether a simple receptor of various energy deposition processes. The high-altitude ionosphere plays an active feedback role by controlling the conductivity at the base of far-reaching magnetic field lines and by providing a plasma source for the magnetosphere. Indeed, the role of the ionosphere during magnetospheric substorms is emerging as a topic for meaningful study in the overall picture of magnetospheric-ionospheric coupling.

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NASA NTRS1988

Remote sensing of atmospheric oxygen from a sounding rocket

This paper describes a rocket experiment to investigate mechanisms governing the interactions between two of the fundamental components of the solar-terrestrial system: the solar ionizing radiation and the earth's upper atmosphere. The aim is to characterize the extreme ultraviolet (EUV) emissions resulting from these interactions in terms of physical parameters so that EUV remote sensing can be gainfully employed as a quantitative diagnostic of the terrestrial atmosphere and plasma environment. The payload consists of a high-resolution (about 0.5 A) spectrometer to measure the EUV emissions (980-1360 A) of the earth's dayglow, a moderate resolution (about 15 A) EUV spectrometer (250-1450 A) to measure the solar irradiation responsible for the photoelectron production, and a hydrogen Lyman Alpha photometer to monitor the solar irradiance and geocoronal emissions.

Chakrabarti, S.↗
NASA NTRS1991

Rapid design of gravity assist trajectories

Several International Solar-Terrestrial Physics (ISTP) missions require the design of complex gravity-assisted trajectories in order to investigate the interaction of the solar wind with the earth's magnetic field. These trajectories present a formidable trajectory design and optimization problem. This paper discusses the philosophy and methodology that enable an analyst to design and analyze such trajectories. The authors describe what is called 'floating end-point' targeting, which allows the inherently nonlinear multiple body problem to be solved with simple linear techniques. This paper demonstrates how floating end-point targeting combines analytic approximations with a Newton method targeter to achieve trajectory design goals quickly, even for the very sensitive double lunar swingby trajectories used by the ISTP missions. A Multiconic orbit integration scheme allows fast and accurate orbit propagation. This paper also describes a prototype software tool, Swingby, which has been built for trajectory design and launch window analysis.

Carrico, J.↗
NASA NTRS1979

User requirements of solar-terrestrial predictions for spacecraft applications

Areas which are influenced by solar-terrestrial coupling effects and which are internal to the Earth's magnetosphere are of interest to mission planners, spacecraft hardware designers, and those engaged in the operation of already orbiting manned or unmanned spacecraft. Accurate models are needed to predict energetic particle flux density, interactions between low energy (10 eV to 100 eV) near-Earth plasma and space systems, and neutral atmospheres. Parameters required for each of these areas are discussed.

Vampola, A. L.↗
NASA NTRS1981

Solar-terrestrial research for the 1980's

The solar-terrestrial system is described. Techniques for observations involving all relevant platforms: spacecraft, the Earth's surface, aircraft, balloons, and rockets are proposed. The need for interagency coordination of programs, efficient data management, theoretical studies and modeling, the continuity of long time series observations, and innovative instrument design is emphasized. Examples of the practical impact of interactions between solar terrestrial phenomena and the environment, including technological systems are presented.

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NASA NTRS1990

A launch window study for GEOTAIL's double lunar swingby trajectory

The GEOTAIL spacecraft of the International Solar-Terrestrial Physics Program will use a series of paired lunar swingbys to explore distant parts of the earth's magnetic tail. A 21-day launch window has been calculated for GEOTAIL, in July and August 1992, to start its distant-tail phase with a first lunar swingby (S1) on September 8, 1992. The main launch window in July utilizes 4.5 revolutions in a transfer orbit to S1, with a mid-August contingency window that uses 2.5 transfer-orbit revolutions before S1. Designing a good distant-tail trajectory, and then accurately matching it at S1 for every day in the launch window, seems to be the easiest and most reliable strategy. However, the total delta-V costs of the current designs can probably be reduced, possibly with the help of new interactive software that can be run on personal computers.

Dunham, David W.↗
NASA NTRS1979

Solar-Terrestrial Predictions Proceedings. Volume 2: Working Group Reports and Reviews

Accurate models are needed to support research in the following areas: spacecraft charging, radiation dosage, transionospheric radio propagation, long and short term solar activity, magnetospheric disturbances, ionospheric interactions, solar weather/climate effects, and geomagnetic applications such as electric power transmission and oil and gas pipeline problems.

Richard F Donnelly↗