Plasmaspheric Wind Simulations

Numerical simulations of the plasmaspheric wind, based on the interchange instability mechanism

Interchange motion was originally introduced in magnetospheric physics by Gold (1959) half a century ago. Various subsequent interpretations, formulations and studies have been proposed since; they are comprehensively introduced and outlined in this document:



Update July 2013: Experimental confirmation of the plasmaspheric wind phenomenon has been obtained in 2013, using Cluster CIS observations by Iannis Dandouras, 20 years after its theoretical prediction by Lemaire and Schunk (1992)


The animations illustrate the different classes of interchange and quasi-interchange motion that plasma elements (ions and electrons) can experience in a dipole magnetic field. At initial time all plasma elements are distributed along segments of dipole magnetic field lines. More detailed explanations on the mechanism, as well as references are available here:


Different modes of MHD oscillations modes and expansion flows (including the plasmaspheric wind flow) are displayed in five animations which are described in more details in a separate file:


Different cases of Interchange and Quasi-Interchange modes (types 1 and 2) are displayed.

  • Animation 1: Animation of Gold's (1959) interchange oscillation. It corresponds to pure-interchange of plasma elements. The plasma elements oscillate back and forth across magnetic field lines, however, without perturbing their distribution.
  • Animation 2: Animation of a pure-interchange mode, which is convectively unstable. This case corresponds to a steady state expansion of plasma elements in the direction transverse to the magnetic field lines.
  • Animation 3: Animation of type 1 Quasi-Interchange mode (transverse mode).
  • Animation 4: Animation of type 2 Quasi-Interchange mode (translational mode).
  • Animation 5: Animation of the plasmaspheric wind.


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