Effects of Auroral-Particle Anisotropies and Mirror Forces on High-Latitude Electric Fields

  1. S.-I. Akasofu and
  2. J.R. Kan
  1. Y. T. Chiu,
  2. J. M. Cornwall and
  3. Michael Schulz

Published Online: 26 MAR 2013

DOI: 10.1029/GM025p0234

Physics of Auroral Arc Formation

Physics of Auroral Arc Formation

How to Cite

Chiu, Y. T., Cornwall, J. M. and Schulz, M. (1981) Effects of Auroral-Particle Anisotropies and Mirror Forces on High-Latitude Electric Fields, in Physics of Auroral Arc Formation (eds S.-I. Akasofu and J.R. Kan), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM025p0234

Author Information

  1. Space Sciences Laboratory, the Aerospace Corporation, P.O. Box 92957 Los Angeles, CA 90009

Publication History

  1. Published Online: 26 MAR 2013
  2. Published Print: 1 JAN 1981

ISBN Information

Print ISBN: 9780875900506

Online ISBN: 9781118664360

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Keywords:

  • Auroras—Addresses, essays, lectures

Summary

Auroral arcs result from the acceleration and precipitation of ring current and/or plasma-sheet plasma in narrow regions characterized by strong electric fields both perpendicular and parallel to the earth's magnetic field. The various mechanisms that have been proposed for the origin of such strong electric fields are not mutually exclusive. However, for most proposed mechanisms (with the possible exception of double layers of Debye length parallel scale), the effects of auroral particle anisotropy, of mirror forces due to the inhomogeneous geomagnetic field, of auroral electron backscatter by the atmosphere, and of electron trapping by the combination of magnetic mirroring and electrostatic forces must be taken into account in simulations of auroral electric fields. In addition, the effects of the very strong perpendicular electric field must also be taken into account in a kinetic description of the Poisson equation in order to achieve a unified theory of the auroral electrostatic structure. In this paper, progress in these areas in the past few years will be reviewed. It is shown that particle anisotropies and mirror forces can account for some basic electrostatic features of the quiet arc, while additional effects may be taking place in strong events in which the parallel potential drop exceeds ∼10 kV.