Bremsstrahlung x ray images of isolated electron patches at high latitudes

Journal Article · Mon Jul 01 04:00:00 EDT 1985 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA090iA07p06515· OSTI ID:5640075

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

Small isolated patches of energetic electron precipitation have been observed at high latitudes with a bremsstrahlung X ray imager in the Stimulated Emission of Energetic Particles (SEEP) payload on the polar-orbiting S81-1 satellite. Twenty-nine patches of X rays (>4 keV) with typical widths of approx.200 km were observed in June 1982 at invariant latitudes between 65/sup 0/ and 83/sup 0/ with a median latitude of 72.5/sup 0/ The majority of X ray patches occurred from dusk until dawn, but a few were present in the early afternoon hours. The observed energy spectra were relatively soft (e fold energies about 1--6 keV) and independent of invariant latitude, magnetic local time, or geomagnetic activity. The occurrence frequency of the patches was somewhat greater at times of high geomagnetic activity. The patches were usually oblong by factors up to 3.7, with a median value of 1.75. No strongly preferred alignment was found. Comparisons of the direct electron measurements and the X ray observations from the same satellite have shown that in some cases the small isolated patches of electron precipitation at high latitudes may undergo significant changes in position on time scales of the order of a few seconds.

• Research Organization: Lockheed Palo Alto Reserach Laboratory, California
• OSTI ID: 5640075
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 90:A7; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BREMSSTRAHLUNG
CHARGED-PARTICLE PRECIPITATION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
ELECTRON PRECIPITATION
IONIZING RADIATIONS
IONOSPHERIC EFFECTS
MAGNETOPAUSE
RADIATIONS
X RADIATION