Isolated electron precipitation regions at high latitudes

Journal Article · Fri Apr 01 04:00:00 EST 1988 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA093iA04p02649· OSTI ID:5229151

Imhof, W L; Voss, H D; Datlowe, D W; Mobilia, J

An investigation has been made at high latitudes of regions or patches of isolated electron precipitation with bremsstrahlung X ray images (>4 keV) and simultaneous particle and 391.4-nm data acquired with the Stimulated emission of Energetic Particles payload on the S81-1 satellite. More extensive analyses of the phenomena than were originally reported (Imhof et al., 1985) have now been made. From this investigation it has been found that when some patch regions are processed with greater sensitivity, nearby weaker patches are found. This characteristic suggests that some of them may be parts of larger structures. There is considerable overlap in spectral shape between patches and larger structures, but the energy spectra of the X rays emitted from the patches are, on the average, softer, even at similar invariant latitudes. Although some patches may be associated with auroral substorms as indicated from comparisons with the AE index, the majority are not and therefore appear not be related to westward traveling surges. Most patches are significantly narrower in one direction, consistent with arc-shaped precipitation. Fine structure is present in some patches, and study of the bremsstrahlung X ray measurements indicates that on a statistical basis many of the spikes associated with the fine structure are spatial and not temporal in nature, suggesting multiple arcs. Also consistent with arc structure, the local time variations have been found to display a similarity to those associated with inverted-V events, but the measured electrons are at higher energies than are normally associated with such events.

• Research Organization: Lockheed Palo Alto Research Laboratory, Palo Alto, California
• OSTI ID: 5229151
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 93:A4; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
BREMSSTRAHLUNG
CHARGED-PARTICLE PRECIPITATION
ELECTROMAGNETIC RADIATION
ELECTRON PRECIPITATION
GEOGRAPHICAL VARIATIONS
IMAGES
LATITUDE EFFECT
MAGNETIC STORMS
RADIATIONS
SPECTRA
TRAVELLING WAVES
VARIATIONS
X-RAY SPECTRA