Relativistic electron acceleration and decay time scales in the inner and outer radiation belts: SAMPEX

Journal Article · Tue Mar 15 04:00:00 EST 1994 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/93GL03532· OSTI ID:6787124

Baker, D N; Kanekal, S ^[1]; Blake, J B ^[2]; Callis, L B ^[3]; Cummings, J R; Mewaldt, R A ^[4]; Zwickl, R D ^[5]; Hovestadt, D; Klecker, B

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1. NASA/Goddard Space Flight Center, Greenbelt, MD (United States)
2. Aerospace Corp., El Segundo, CA (United States)
3. NASA/Langley Research Center, Hampton, VA (United States)
4. California Institute of Technology, Pasadena, CA (United States)
5. NOAA/Space Environment Lab., Boulder, CO (United States)

High-energy electrons have been measured systematically in a low-altitude (520 [times] 675 km), nearly polar (inclination = 82[degrees]) orbit by sensitive instruments onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX). Count rate channels with electron energy thresholds ranging from 0.4 MeV to 3.5 MeV in three different instruments have been used to examine relativistic electron variations as a function of L-shell parameter and time. A longer run of essentially continuous data (July 1992-July 1993) shows substantial acceleration of energetic electrons throughout much of the magnetosphere on rapid time scales. This acceleration appears to be due to solar wind velocity enhancement and is surprisingly large in that the radiation belt [open quotes]slot[close quotes] region often is filled temporarily and electron fluxes are strongly enhanced even at very low L-values (L [approximately] 2). A superposed epoch analysis shows that electron fluxes rise rapidly for 2.5 [le] L [le] 5. These increases occur on a time scale of order 1-2 days and are most abrupt for L-values near 3. The temporal decay rate of the fluxes is dependent on energy and L-value and may be described by J = Ke-t/t[sup o] with t[sub o] [approximately] 5-10 days. Thus, these results suggest that the Earth's magnetosphere is a cosmic electron accelerator of substantial strength and efficiency. 12 refs., 5 figs.

• OSTI ID: 6787124
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 21:6; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
COSMIC ELECTRONS
COSMIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ENERGY LOSSES
ENERGY RANGE
FERMIONS
IONIZING RADIATIONS
LEPTONS
LOSSES
RADIATION BELTS
RADIATIONS
RELATIVISTIC RANGE
SECONDARY COSMIC RADIATION
TAIL ELECTRONS