Plasmasphere and Ring Current Electric Fields Observed by Geos 2

  1. T. E. Moore,
  2. J. H. Waite Jr.,
  3. T. W. Moorehead and
  4. W. B. Hanson
  1. R. Schmidt and
  2. A. Pedersen

Published Online: 18 MAR 2013

DOI: 10.1029/GM044p0079

Modeling Magnetospheric Plasma

Modeling Magnetospheric Plasma

How to Cite

Schmidt, R. and Pedersen, A. (1988) Plasmasphere and Ring Current Electric Fields Observed by Geos 2, 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/GM044p0079

Author Information

  1. Space Science Department of Esa/Estec, Noordwijk, The Netherlands

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 electric field double probe data from GEOS 2 have been statistically examined to study the consecutive passage of the afternoon plasmaspheric bulge and the trough at the geostationary orbit. It was found that the average location of the bulge depends on the magnetic activity and was encountered at earlier local times for higher magnetospheric activity. Within the bulge the electric field showed very frequently a typical directional change from dawnward outside to duskward inside the bulge. The magnitude of the magnetic field was frequently much smaller near the outbound crossing of the plasmaspheric bulge than is expected from a long-term average. The E×B/B2 drift pointed azimuthally eastward prior to the encounter of the bulge and rotated into the sunward direction within the bulge. Following its passage through the dense, cold plasma in the bulge, GEOS 2 encountered a hot and tenuous plasma sheet-type plasma in the trough that occasionally corrupted the electric field measurements. Generally, the electric field in the trough is much smaller than in the bulge. A possible cause of the sunward plasma flow within the bulge is discussed on the basis of these data.