Ion Anisotropy-Driven Waves in the Earth'S Magnetosheath and Plasma Depletion Layer

  1. J. L. Burch and
  2. J. H. Waite Jr.
  1. Richard E. Denton1,
  2. Brian J. Anderson2,
  3. Stephen A. Fuselier3,
  4. S. Peter Gary4 and
  5. Mary K. Hudson1

Published Online: 18 MAR 2013

DOI: 10.1029/GM084p0111

Solar System Plasmas in Space and Time

Solar System Plasmas in Space and Time

How to Cite

Denton, R. E., Anderson, B. J., Fuselier, S. A., Gary, S. P. and Hudson, M. K. (1994) Ion Anisotropy-Driven Waves in the Earth'S Magnetosheath and Plasma Depletion Layer, in Solar System Plasmas in Space and Time (eds J. L. Burch and J. H. Waite), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM084p0111

Author Information

  1. 1

    Physics and Astronomy Department, Dartmouth College, Hanover, New Hampshire

  2. 2

    Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland

  3. 3

    Lockheed Palo Alto Research Laboratory, Palo Alto, California

  4. 4

    Los Alamos National Laboratory, Los Alamos, New Mexico

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1994

ISBN Information

Print ISBN: 9780875900414

Online ISBN: 9781118663851

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Keywords:

  • Solar wind;
  • Space plasmas;
  • Magnetosphere

Summary

Recent studies of low-frequency waves (ω ≤ Ω p , where Ω p is the proton gyrofrequency) observed by AMPTE/CCE in the plasma depletion layer and magnetosheath proper are reviewed. These waves are shown to be well identified with ion cyclotron and mirror mode waves. By statistically analyzing the transitions between the magnetopause and time intervals with ion cyclotron and mirror mode waves, it is established that the regions in which ion cyclotron waves occur are between the magnetopause and the regions where the mirror mode is observed. This result is shown to follow from the fact that the wave spectral properties are ordered with respect to the proton parallel beta, βp . The later result is predicted by linear Vlasov theory using a simple model for the magnetosheath and plasma depletion layer. Thus, the observed spectral type can be associated with relative distance from the magnetopause. The anisotropy-beta relation, Ap ≡ (T /T ) p − 1 = 0.85βp −0.48, results from the fact that the waves pitch angle scatter the particles so that the plasma is near marginal stability, and is a fundamental constraint on the plasma.