Streaming reversal of energetic particles in the magnetetail during a substorm

Journal Article · Thu Mar 01 04:00:00 EST 1984 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA089iA03p01540· OSTI ID:6218157

Lui, A T.Y.; Williams, D J; Eastman, T E; Frank, L A; Akasofu, S

Reversal from tailward streaming to earthward streaming of energetic ions at 0.29--0.50 MeV during a substorm on February 3, 1978, is studied with measurements of energetic particles, plasma, and magnetic field from that IMP 8 spacecraft near the dusk flank of the magnetotail. Four new features emerge when high time resolution data are examined in detail. The times of reversal from tailward to earthward streaming of energetic ions and from tailward to earthward plasma flow do not coincide. Second, the velocity distribution in the tailward flowing plasma has a cresent shape, whereas the velocity distribution in the earthward flowing plasma has a crescent shape, whereas the velocity distribution in the earthward flowing plasma resembles a convecting Maxwellian. Third, tailward streaming of energetic ions is sometime detected in northward magnetic field regions and conversely, earthward streaming in southward field environments. Fourth, energetic ions scattering earthward are occasionally present in conjunction with a strong tailward streaming population in the same energy range. These new features suggest that the streaming reversal of energetic ions and the plasma flow reversal in this event are due to the spacecraft traversing different plasma regions during the substorm-associated configurational change of the plasma sheet and the magnetotail and is unrelated to the motion of an acceleration region such as an X type neutral line moving past the spacecraft.

• Research Organization: Applied Physics Laboratory, Johns Hopkins University
• OSTI ID: 6218157
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 89:A3; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
DISTRIBUTION FUNCTIONS
EARTH ATMOSPHERE
FUNCTIONS
IMP SATELLITES
MAGNETIC BAYS
MAGNETOSPHERE
MAGNETOTAIL
PLASMA ACCELERATION
PLASMA DRIFT
RADIATION STREAMING
SATELLITES