Evolution of magnetic configurations in the plasma sheet during a substorm on March 19, 1978

Journal Article · Sun Sep 01 04:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA01406· OSTI ID:5221552

Sun, W; Kan, J R; Akasofu, S I ^[1]

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1. Univ. of Alaska, Fairbanks (United States)

Evolution of the magnetic field configuration in the plasma sheet is modeled for an intense substorm event on March 19, 1978. The model is based on the idea that the substorm enhanced field-aligned currents are initiated in the ionosphere in response to an enhanced magnetospheric convection. The field-aligned currents in the model are determined from the ground-based magnetometer data with a time resolution of 5 min. The substorm field-aligned currents are assumed to close in the plasma sheet to complete the substorm current circuit. It is shown that the magnetic field produced by the substorm current system in the model can reproduce several important substorm signatures observed in the plasma sheet. These signatures include the taillike reconfiguration in the plasma sheet during the growth phase, the dipolarization of the plasma sheet associated with the substorm expansion onset, and the formation of a new X line. A shortcoming of the model is that the plasma dynamics in the plasma sheet have been ignored. In spite of this shortcoming, however, the model demonstrates that the ionosphere, in response to an enhanced magnetospheric convection, can cause the plasma sheet to change its magnetic configuration to result in the substorm signatures observed in the plasma sheet. The present study shows that it is possible for the ionosphere to play an active role in causing the observed reconfigurations of the plasma sheet during substorms.

• OSTI ID: 5221552
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A9; 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
CONVECTION
CURRENTS
DYNAMICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
ENERGY TRANSFER
HEAT TRANSFER
INTERACTIONS
IONOSPHERE
MAGNETIC BAYS
MAGNETIC FIELD CONFIGURATIONS
MASS TRANSFER
MATHEMATICAL MODELS
MECHANICS
PLANETARY IONOSPHERES
PLASMA SHEET
SOLAR ACTIVITY
SOLAR WIND