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ISEE observations of low frequency waves and ion distribution function evolution in the plasma sheet boundary layer
Author(s) -
Elphic R. C.,
Gary S. P.
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i011p02023
Subject(s) - plasma sheet , physics , ion , scattering , amplitude , distribution function , plasma , pitch angle , computational physics , atomic physics , magnetosphere , current sheet , boundary layer , geophysics , optics , magnetohydrodynamics , mechanics , quantum mechanics
This paper describes ISEE plasma and magnetic fluctuation observations during two crossings of the plasma sheet boundary layer in the Earth's magnetotail. Distribution function observations show that the counterstreaming ion components undergo pitch‐angle scattering and evolve into a shell distribution in velocity space. This evolution is correlated with the development of low frequency, low amplitude magnetic fluctuations. However, the measured wave amplitudes are insufficient to accomplish the observed degree of ion pitch‐angle scattering locally; the near‐Earth distributions may be the result of processes occurring much farther down the magnetotail. Our results show a clear correlation between the ion component beta and the relative streaming speed of the two components, suggesting that electromagnetic ion/ion instabilities do play an important role in the scattering of PSBL ions.