MHD drift ballooning instability near the inner edge of the near-Earth plasma sheet and its application to substorm onset

ZY Pu*, A Korth, ZX Chen, RHW Friedel, QC Zong, XM Wang, MH Hong, SY Fu, ZX Liu, T.I. Pulkkinen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The MHD drift ballooning mode (DBM) instability near the inner edge of the near-Earth plasma sheet is studied by using both the one-fluid generalized progressing wave expansion method and the two-fluid approach. It is found that in the frame of reference at rest relative to the bulk plasma the DBM may become a purely growing mode in two distinct circumstances, which, for convenience, are called the DBM1 and DBM2, respectively, The beta threshold for the DBM1 is identical with that derived by Ohtani and Tamao [1993] and Southwood and Kivelson [1987], while the criterion of the DBM2 covers that of Miura et al. [1989]. Comparisons of the theory with GEOS 2 data show that the DBM2 is more easily excited in the late substorm growth phase. There is considerable evidence that the DBM is generated at expansion onsets, The characteristic features of magnetic field dipolarization can be interpreted in terms of the development of the DBM. The extremely thin current sheet cases should be studied with approaches other than those used in this work.

Original languageEnglish
Pages (from-to)14397-14406
Number of pages10
JournalJournal of geophysical research: Space physics
Volume102
Issue numberA7
DOIs
Publication statusPublished - 1 Jul 1997
MoE publication typeA1 Journal article-refereed

Keywords

  • INTERCHANGE INSTABILITY
  • GEOMAGNETIC-PULSATIONS
  • GEOS-2 OBSERVATIONS
  • MAGNETOSPHERE
  • WAVES
  • MODEL
  • MAGNETOTAIL
  • TRIGGER
  • ALFVEN

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