The Role of Currents in Plasma Redistribution
- Thomas A. Potemra
Published Online: 21 MAR 2013
Copyright 1984 by the American Geophysical Union.
How to Cite
Atkinson, G. (1984) The Role of Currents in Plasma Redistribution, in Magnetospheric Currents (ed T. A. Potemra), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM028p0325
- Published Online: 21 MAR 2013
- Published Print: 1 JAN 1984
Print ISBN: 9780875900551
Online ISBN: 9781118664131
- Magnetospheric currents—Congresses;
- Plasma instabilities—Congresses
Cross-field currents in the outer magnetosphere, both polarization and field-gradient drift are carried by protons and positive ions because of their greater mass and energy. Field-aligned currents are believed to be carried by electrons because of their greater mobility. If a given current-system contains both, then there is a plasma density build-up on flux tubes containing downward field-aligned current and a plasma decrease on flux tubes containing upward current. Thus field-aligned currents are the signature of a redistribution of plasma in the magnetosphere. Three particular examples are studied: (1) the familiar example of a drifting plasma blob, (2) Region II currents and the inner edge of plasma penetration, (3) the dusk Region I and the electrojet closure currents. These last are sufficiently intense to indicate significant plasma redistribution both in and in between substorms. The result is a revision of models of convection in from the tail and of the magnetospheric properties. The upward currents form a single continuous current sheet separating strongly inflated flux tubes from more dipolar flux tubes. The substorm fits naturally into the model and plasma depletion on flux tubes carrying upward field aligned currents is responsible for triggering, expansion and westward development of the substorm as well as between substorm flows.