Evolution of the earth's distant magnetotail: ISEE 3 electron plasma results

Journal Article · Sun Dec 01 04:00:00 EST 1912 · J. Geophys. Res.; (United States)

OSTI ID:7204772

Zwickl, R D; Baker, D N; Bame, S J; Feldman, W C; Gosling, J T; Hones, Jr, E W; McComas, D J; Tsurutani, B T; Slavin, J A

Electron plasma measurements made by ISEE 3 from October 18, 1982, through April 19, 1983, were examined for signatures identifying the spatial evolution of the earth's magnetotail out to distances of approx.225 R/sub E/. Nearly 91,000 individual electron spectra were combined into a data set in which each point was first labelled as being magnetosheath, lobe, or plasma sheet and then separated into one of four radial-distance bins. The lobe density distribution shows two peaks near earth (< or =60 R/sub E/), a narrow peak at approx.10/sup -2/ cm/sup -3/ representing quiet lobe, and a second broader peak above 10/sup -1/ cm/sup -3/ representing boundary layer phenomena. At larger distances the lower density peak disappears and the remaining density peak (at approx.10/sup -1/ cm/sup -3/) becomes broader and contains a high density tail which extends well above 1 cm/sup -3/. The increase in lobe density at large distances is believed to be due to plasma which crosses the magnetopause on open field lines along its flanks and drifts inward toward the plasma sheet. The plasma sheet density distribution shows only a slight decrease in density at larger radial distances. The temperature of the plasma sheet and lobe electron plasma decreases with increasing distance, with the plasma sheet temperature decreasing at a faster rate. Evolution in the density and temperature of the electron plasma in the magnetotail results in a situation wherein it is often difficult to separate plasma sheet from lobe plasma at large radial distances by these two parameters alone. The bulk flow velocity of the plasma sheet and lobe plasma increases dramatically at larger radial distances. The electron bulk velocity observed in the plasma sheet beyond 180 R/sub E/ often exceeds the normal solar wind velocity range (300--700 km/s).

• Research Organization: University of California, Los Alamos National Laboratory, New Mexico
• OSTI ID: 7204772
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 89:A12; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH ATMOSPHERE
ELECTRON DENSITY
ELECTRON DRIFT
ELECTRON TEMPERATURE
ENERGY SPECTRA
EXPLORER SATELLITES
MAGNETOSPHERE
MAGNETOTAIL
PLASMA SHEET
SATELLITES
SPECTRA