Field-Aligned Currents Near the Magnetosphere Boundary
- Thomas A. Potemra
Published Online: 21 MAR 2013
Copyright 1984 by the American Geophysical Union.
How to Cite
Hones, E. W. (1984) Field-Aligned Currents Near the Magnetosphere Boundary, in Magnetospheric Currents (ed T. A. Potemra), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM028p0171
- Published Online: 21 MAR 2013
- Published Print: 1 JAN 1984
Print ISBN: 9780875900551
Online ISBN: 9781118664131
- Magnetospheric currents—Congresses;
- Plasma instabilities—Congresses
This paper describes present thinking about the structure of magnetospheric boundary layers and their roles in the generation of the field-aligned currents that are observed in the polar regions. A principal effect of the momentum loss by magnetosheath plasma to the magnetosphere boundary regions just within the magnetopause, whether it be by a diffusive process or by magnetic reconnection, is the tailward pulling of the surface flux tubes relative to those deeper below the surface. The dayside region 1 currents at low altitudes flow along field lines in the resulting regions of magnetic shear. The direction of the shear and its magnitude, actually measured in the boundary region, confirm that the polarities and intensities of the dayside region 1 currents can be accounted for by this process. The low latitude boundary layer, formerly thought to be threaded entirely by closed field lines, now appears to contain at least some open field lines, newly reconnected, that are in the process of being swept into the high latitude tail to form the plasma mantle. The open flux tubes of the flux transfer events, thought to be the product of “patchy reconnection” have a spiral magnetic structure whose helicity is such as to suggest currents having the polarities of the region 1 currents.