Refilling of a Plasmasphere Flux Tube–Microscopic Plasma Processes

  1. T. E. Moore,
  2. J. H. Waite Jr.,
  3. T. W. Moorehead and
  4. W. B. Hanson
  1. N. Singh

Published Online: 18 MAR 2013

DOI: 10.1029/GM044p0087

Modeling Magnetospheric Plasma

Modeling Magnetospheric Plasma

How to Cite

Singh, N. (1988) Refilling of a Plasmasphere Flux Tube–Microscopic Plasma Processes, 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/GM044p0087

Author Information

  1. Department of Electrical and Computer Engineering, The University of Alabama in Huntsville, Huntsville, Alabama 35899

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


Microscopic plasma processes, which facilitate the refilling of the outer plasmaspheric flux tubes after geomagnetic storms by thermalizing and/or trapping the ions in the flux tubes, are studied. The formation of electrostatic shocks in the equatorial region, where the plasma streams originating from the conjugate ionospheres collide, is examined by computer simulations. The mechanism and the conditions for the shock formation are given. A shock pair forms when Te > 3 Ti and the stream velocity Vb lies in the range 1.3 Vti < Vb < 2.3 Co , where Te and Ti are the electron and ion temperatures, Co is the ion-acoustic speed, and Vti is the ion thermal velocity. When Vb > 2.3 Co′ counter-streaming is expected to continue. Starting with Te ˜ Ti in the ionosphere, shock formation requires a preferential heating of electrons in the equatorial region. In the shocked plasma, electrons are found to be non-Maxwellian. It is shown that a plasma model consisting of two-fluid hydrodynamic treatment for the ion streams originating in the congugate ionospheres and a non-Boltzmann distribution consisting of trapped and free electrons can be successful in including the features of electrostatic shocks in the refilling. The effect of perpendicular ion heating by an extended plasma turbulence along the field lines on the reilling is examined suggesting that an extremely low level of the turbulence with a power spectral density ≲10−11 v2 m−2 Hz−1 near the ion-cyclotron frequency can be effective in trapping the ions in the flux tubes. A localized perpendicular ion heating in the equatorial region produces a potential barrier for the ionospheric plasma streams. The potential barrier can stop the interhemispheric flow.