Plasma flow reversals at the dayside magnetopause and the origin of the asymmetric polar cap convection

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA06p08073· OSTI ID:5376332

Gosling, J T; Thomsen, M F; Bame, S J; Elphic, R C ^[1]; Russell, C T ^[2]

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1. Los Alamos National Lab., NM (USA)
2. Univ. of California, Los Angeles (USA)

A number of events have been observed in the Los Alamos/Garching fast plasma experiment data from ISEE 2 within {plus minus} 3 hours of noon wherein the y component of the plasmas flow within the low latitude boundary layer and magnetopause current layer is oppositely directed to that in the adjacent magnetosheath. When the y component, B{sub y}, of the local magnetosheath magnetic field is positive, events of this nature are found preferentially in the northern dusk and southern dawn quadrants, and when B{sub y} is negative, they are found preferentially in the opposite two quadrants. Plasma flows in these events are always also poleward, that is they are always directed away from the GSE equatorial plane. The observations are qualitatively and quantitatively consistent with previous observations of accelerated flows at the magnetopause and with models of magnetic reconnection, with the reconnection occurring at low latitudes near the GSE XY plane independent of the magnitude or the sign of the y component of the local magnetosheath magnetic field. Local magnetic shears at the magnetopause for these events range from 60 to 180 degs, which, together with the occurrence of these events at low latitudes, does not tend to support the antiparallel merging hypothesis. These observations of B{sub y}-dependent flow reversals provide a graphic demonstration of how asymmetric polar cap convection and related phenomena, such as the Svalgaard-Mansurov effect, originate in magnetic reconnection at the dayside magnetopause.

• OSTI ID: 5376332
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A6; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ASYMMETRY
CONVECTION
ENERGY TRANSFER
HEAT TRANSFER
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETIC RECONNECTION
MAGNETOPAUSE
MAGNETOSHEATH
MASS TRANSFER
ORIGIN
PLASMA DRIFT
POLAR REGIONS
SATELLITES
SHEAR