The evolution of mirror mode fluctuations in the terrestrial magnetosheath

M. Tátrallyay, G. Erdős

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Mirror type fluctuations were identified in magnetic field data measured aboard the ISEE-1/2 spacecraft in different regions of the magnetosheath. Minimum variance analysis was applied to find the mirror type fluctuations, and the amplitude of the fluctuations was determined individually. Assuming that the source of the mirror mode instability is at the bow shock, the growth rate of the field strength perturbations was determined for four selected magnetosheath passes when mirror type fluctuations were observed in the outer, middle, and inner region of the sheath. The obtained growth rate values are in the range 0.002 s-1 <γ <0.0035 s-1 being almost an order of magnitude smaller than the maximum growth rate values calculated by Gary et al. (J. Geophys. Res. 98 (1993) 1481) based on a numerical evaluation of the full kinetic dispersion relation. The significant difference between the observed and calculated growth rate values can be explained if the mirror type fluctuations observed in different regions of the magnetosheath do not always originate from the bow shock, but the source may be somewhere else (e.g. at the magnetopause, inside the magnetosheath, or in localized regions of the bow shock). Also, the linear approximation applied in the above-mentioned calculations may be inappropriate for describing the growth of the observed fluctuations.

Original languageEnglish
Pages (from-to)593-599
Number of pages7
JournalPlanetary and Space Science
Volume50
Issue number5-6
DOIs
Publication statusPublished - Apr 2002

Fingerprint

magnetosheath
mirrors
bows
shock
magnetopause
variance analysis
International Sun Earth Explorers
spacecraft
perturbation
magnetic field
sheaths
kinetics
field strength
evaluation
approximation
magnetic fields

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

The evolution of mirror mode fluctuations in the terrestrial magnetosheath. / Tátrallyay, M.; Erdős, G.

In: Planetary and Space Science, Vol. 50, No. 5-6, 04.2002, p. 593-599.

Research output: Contribution to journalArticle

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