The effects of a magnetic B sub y component on geomagnetic tail equilibria

Journal Article · Sat Aug 01 00:00:00 EDT 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA08p08660· OSTI ID:5736776

Hilmer, R V; Voigt, G ^[1]

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1. Rice Univ., Houston, TX (United States)

Positive correlations of the magnetic y component of the IMF with those of both the magnetotail lobes and plasma sheet show a B{sub y} component pervading the quiet magnetotail with enhanced strength near the neutral sheet (z = 0). A model constructed using linear solutions to the Grad-Shafranov equation for two-dimensional tail equilibria explains these and related observations in terms of MHD equilibrium theory. The authors conclude that the enhanced B{sub y} values must be an essential part of the quiet magnetotail and do not result from a simple intrusion of the IMF. The B{sub y} field consists of a constant background component plus a nonuniform field existing only in the plasma sheet, where it is dependent on the plasma parameter {beta} and the strength of the magnetic B{sub Z} component. B{sub y} is strongest at the neutral sheet and decreases monotonically in {+-} z direction, reaching a constant tail lobe value at the plasma sheet boundaries. Field lines are tilted about the tail axis with the angle of ascent in the y-z plane being greatest at z = 0. This is also the region of greatest field line rotation in the x-y plane, insuring that magnetic reversal always occurs near the neutral sheet. The maximum change in field direction between tail lobes is less than 180{degrees} with field lines most closely aligned with the tail axis at the plasma sheet boundaries. The presence of a significant positive B{sub y} component produces currents, including field-aligned currents, that flow through the equatorial plane and toward and away from earth in the northern and southern halves of the plasma sheet, respectively.

• OSTI ID: 5736776
• Journal Information: Journal of Geophysical Research; (United States), Vol. 92:A8; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
MAGNETOTAIL
MHD EQUILIBRIUM
BOUNDARY LAYERS
CORRELATIONS
ELECTRIC CURRENTS
GEOMAGNETIC FIELD
INTERPLANETARY MAGNETIC FIELDS
MATHEMATICAL MODELS
PLASMA SHEET
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EQUILIBRIUM
LAYERS
MAGNETIC FIELDS
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)