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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 1,549 records · Page 86
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NASA NTRS1971

Plasma clouds in the magnetosphere

Magnetospheric plasma clouds equatorial observation by ATS 5 satellite, revealing plasma injection during substorms and dispersion by earth magnetic and electric fields

Deforest, S. E.↗
NASA NTRS1971

Characteristics of magnetosheath plasma observed at low altitudes in the dayside magnetospheric cusps

Magnetosheath plasma penetrating to low altitudes in the dayside cusp region of the magnetosphere has been observed by the ISIS 1 soft particle spectrometer (SPS). The extent of these particle fluxes in local magnetic time and invariant latitude, their variation with magnetic activity, and their pitch angle distribution are given. Comparison between the SPS data and energetic particle data indicates that the boundary between open and closed field lines on the dayside is associated with a sharp drop in the outer zone keV electron fluxes. It is shown that these newly identified cusp fluxes provide the necessary energy to produce observed dayside auroral oval phenomena.

Winningham, J. D.↗
NASA NTRS1970

Magnetotail changes in relation to the solar wind magnetic field and magnetospheric substorms

An attempt is made to understand some of the magnetotail dynamics by using simultaneous observations from several satellites: Explorers 33 and 35 in the solar wind, IMP 4 in the near magnetotail (30 RE), ATS 1, and OGO 5 in the magnetosphere. It was observed that in the main lobes of the tail the magnetic field increases slowly when the interplanetary magnetic field turns southward, and can decrease slowly after a substorm. The plasma sheet changes indicate a thinning when the interplanetary magnetic field turns southward and an expansion when it turns northward. When combined with the plasma sheet expansion, which has been observed to follow a substorm, these results allow a schematic view of the relations between the changes in the orientation of the solar wind magnetic field, the substorms, and the changes in the tail parameters to be developed.

Aubry, M. P.↗
NASA NTRS1972

Magnetospheric radio noise

Observations, made by the RAE satellite, of earth magnetospheric noise are reported. The observations show radio noise exists at 700 kHz and below. The results are included in graphs.

Kaiser, M.↗
NASA NTRS1972

Wave propagation in the magnetosphere of Jupiter

A systematic procedure is developed for identifying the spatial regimes of various modes of wave propagation in the Jupiter magnetosphere that may be encountered by flyby missions. The Clemmow-Mullaly-Allis (CMA) diagram of plasma physics is utilized to identify the frequency regimes in which different modes of propagation occur in the magnetoplasma. The Gledhill model and the Ioannidis and Brice model of the magnetoplasma are summarized, and configuration-space CMA diagrams are constructed for each model for frequencies from 10 Hz to 1 MHz. The distinctive propagation features, the radio noise regimes, and the wave-particle interactions are discussed. It is concluded that the concentration of plasma in the equatorial plane makes this region of vital importance for radio observations with flyby missions. Local radio noise around the electron cyclotron frequency will probably differ appreciably from its terrestrial counterpart due to the lack of field-line guidance. Hydromagnetic wave properties at frequencies near the ion cyclotron frequency and below will probably be similar to the terrestrial case.

Liemohn, H. B.↗
NASA NTRS1972

Magnetic field signatures of substorms on high latitudes field lines in the nighttime magnetosphere

Two types of magnetic field changes are repeatedly observed in the high latitude nightside magnetosphere in association with magnetic substorms. One type is characterized by sudden decrease in the field strength, accompanied by an abrupt perturbation in the field declination angle. These changes are attributed to field aligned-sheet currents flowing on the high latitude boundary of an expanding plasma sheet following substorms. Single sheets of field-aligned currents on this boundary tend to flow toward the earth in the morning quadrant and away in the evening. Multiple sheets of current may also occur, with the direction of the high latitude sheet generally being the same as for a single sheet. A second type of field change is a decrease in field inclination during substorms. This is regarded as a manifestation of the changing field configuration during substorms and can be described in terms of azimuthal currents.

Fairfield, D. H.↗
NASA NTRS1972

Magnetospheric electrons

Coupling of source, transport, and sink processes produces a fairly accurate model for the macroscopic structure and dynamics of magnetospheric electrons. Auroral electrons are controlled by convective transport from a plasma sheet source coupled with a precipitation loss due to whistler and electrostatic plasma turbulence. Outer and inner zone electrons are governed by radial diffusion transport from convection and acceleration sources external to the plasmapause and by parasitic precipitation losses arising from cyclotron and Landau interactions with whistler and ion cyclotron turbulence.

Coroniti, F. V.↗