Observational support for the current sheet catastrophe model of substorm current disruption

Journal Article · Fri Aug 21 04:00:00 EDT 1992 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/92GL01615· OSTI ID:6967543

Burkhart, G R; Dusenbery, P B; Speiser, T W ^[1]; Lopez, R E ^[2]

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1. Univ. of Colorado, Boulder (United States) NOAA Space Environment Lab., Boulder, CO (United States)
2. Applied Research Corp., Landover, MD (United States)

It has recently been found that a one-dimensional current sheet equilibrium with a non-zero convection electric field, E[sub y], and a non-zero normal magnetic field component, B[sub n], can reach a point of catastrophe through either the reduction of the drift velocity, [upsilon][sub D] = cE[sub y]/B[sub n] or the increase of B[sub n]. This point of catastrophe coincides with a value of [kappa][sub A] [approx equal] 0.7, where [kappa][sub A] is the self-consistent value of [kappa] = (R[sub min]/[rho][sub A max])[sup 1/2] corresponding to ions of average energy. (Here R[sub min] is the minimum field-line radius of curvature and [rho][sub A max] is the maximum gyroradius for ions of average energy.) The point of catastrophe was found to be preceded by a twisting of the current sheet field-lines into the dawnward direction, i.e., by the development of a y-component of B, with odd symmetry in z, and a sign opposite B[sub x], where positive x is earthward, positive y is in the dawn-to-dusk direction and positive z is northward. Since the loss of the current sheet would causee the local configuration to become more dipolar, it was suggested that the catastrophic loss of the local current sheet equilibrium could correspond to local current disruption and dipolarization. In this paper, observations of some of the signatures predicted by theory are presented.

• OSTI ID: 6967543
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 19:16; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
CONVECTION
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTROJETS
ENERGY TRANSFER
EQUILIBRIUM
HEAT TRANSFER
ION DRIFT
MAGNETIC BAYS
MAGNETIC FIELDS
MAGNETOTAIL
MASS TRANSFER
MATHEMATICAL MODELS