Electric Fields and Particle Precipitation During the Substorm of January 18, 1984

  1. T. E. Moore,
  2. J. H. Waite Jr.,
  3. T. W. Moorehead and
  4. W. B. Hanson
  1. O. de la Beaujardière1,
  2. D. S. Evans2,
  3. Y. Kamide3 and
  4. R. Lepping4

Published Online: 18 MAR 2013

DOI: 10.1029/GM044p0165

Modeling Magnetospheric Plasma

Modeling Magnetospheric Plasma

How to Cite

Beaujardière, O. d. l., Evans, D. S., Kamide, Y. and Lepping, R. (1988) Electric Fields and Particle Precipitation During the Substorm of January 18, 1984, in Modeling Magnetospheric Plasma (eds T. E. Moore, J. H. Waite, T. W. Moorehead and W. B. Hanson), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM044p0165

Author Information

  1. 1

    Geoscience and Engineering Center, SRI International, Menlo Park, California 94025.

  2. 2

    Space Environment Laboratory, NOAA, Department of Commerce, Boulder, Colorado 80303.

  3. 3

    Kyoto Snagyo University, Kamigamo, Kita-ku, Kyoto, Japan.

  4. 4

    Laboratory for Extraterrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771.

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780875900704

Online ISBN: 9781118664414



  • Space plasmas—Mathematical models;
  • Magnetosphere—Mathematical models;
  • Ionosphere—Mathematical models


The purpose of this paper is to examine the transition between quiet and active conditions in the early afternoon high-latitude ionosphere. How the electric field and particle precipitation respond to a slow monotonic decrease in the interplanetary magnetic field Bz component is investigated. Observations from the Sondrestrom incoherent-scatter radar and the NOAA 7 satellite are presented. It is shown that the electric field intensifies very quickly (∼15 min) after the change in Bz. Around 1430 MLT, the latitude of the convection reversal moves poleward during the time when Bz is decreasing, but still positive. During this time, the precipitation from the central plasma sheet electrons also moves poleward, although at a slower rate. On two consecutive passes, there is no central plasma sheet electron precipitation. These observations are contrary to what is predicted by steady state calculations and empirical models. They may be explained in terms of the temporal and spatial variations of the adiabatic motion of ∼1-keV electrons, under the influence of a convection electric field that is abruptly increased. Other observations concern the relative position of the plasma sheet boundary layer and the convection reversal. The plasma convection reversal appears to move from the equatorward to the poleward then back to the equatorward edge of the boundary layer precipitation. This relative motion is also interpreted in terms of a transient response. The speculation is that the convection responds quickly to changes in the solar wind convection, whereas the electrons are slower to adapt to the new configuration of the convection.