Simultaneous multispacecraft observations of energetic proton bursts inside and outside the magnetosphere

Journal Article · Fri Sep 01 04:00:00 EDT 1978 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA083iA09p04289· OSTI ID:6566118

Sarris, E T; Krimigis, S M; Bostrom, C O; Armstrong, T P

Energetic (E/sub rho/> or approx. =0.21,0.29MeV) proton bursts have been observed simultaneously by the Johns Hopkins University Applied Physics Laboratory experiments on three earth-orbiting (Imp 6.350km x approx.32R/sub E/;Imp7,approx.32R/sub E/ x ;Imp8,approx.25R/sub E/ x 43R/sub E/) spacecraft, separated by several earth radii both inside and outside the earth's magnetosphere over the period October 1972 through August 1974. It is shown that proton bursts are present nearly simultaneously in the vicinity of the outer belt trapping boundary, in the low-latitude magnetotail, in the magnetosheath, and upstream from the bow shock. Large intensity differences (up to 10/sup 3/) are seen among the three spacecraft, with the highest fluxes generally observed near the neutral sheet and outside the outer belt and the lowest inside the tail lobes at vertical-barZ/sub SM/vertical-bar>10 R/sub E/. However, intensity gradients can change sign between successive bursts a few minutes apart, a new or moving source being suggested. Time delays in burst onset from one spacecraft to the next ranging up to 30 min are observed and are attributed to propagation effects from the source to the point of observation. In some cases, particle onsets upstream from the bow shock precede those inside the magnetosphere. The energy spectra for a given burst are shown to be harder outside the magnetosphere than inside, a feature suggesting a rigidity-dependent mechanism for particle escape into the interplanetary medium. Energetic (E/sub e/> or approx. =0.22 MeV) electron bursts were generally, but not always, seen to be associated with the protons; intensity differences in the electrons were very large (approx.10/sup 3/) between points within the plasma sheet and outside the magnetosphere, a finding reenforcing the suggestion for rigidity dependence in the propagation process.

• Research Organization: Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland 20810
• OSTI ID: 6566118
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 83:A9; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTRONS
ELEMENTARY PARTICLES
ENERGY SPECTRA
FERMIONS
IMP SATELLITES
INTERPLANETARY SPACE
LEPTONS
MAGNETOSHEATH
MAGNETOTAIL
PLASMA SHEET
PROTON DENSITY
RADIATION BELTS
SATELLITES
SPACE
SPECTRA