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On the absence of plasma wave emissions and the magnetic field orientation in the distant magnetosheath
Author(s) -
Coroniti F. V.,
Greenstadt E. W.,
Moses S. L.,
Tsurutani B. T.,
Smith E. J.
Publication year - 1994
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 - 10.1029/94gl01583
Subject(s) - magnetosheath , physics , amplitude , plasma , magnetosphere , magnetic field , waves in plasmas , wake , geophysics , magnetopause , computational physics , optics , mechanics , quantum mechanics
In early September, 1983 ISEE‐3 made a long traversal of the distant dawnside magnetosheath starting near x = −150 R E downstream. The distant magnetosheath often contains moderately intense plasma wave emissions at frequencies from several hundred Hz to 5 kHz. However, over time scales of many days, a clear correlation exists between the occurrence of the plasma waves and the cone angle (θ xB ) between the magnetic field and the plasma flow velocity (x‐direction). For θ xB large (small), the plasma wave amplitudes are near background (high). Sudden ( < 1 minute) changes in the local magnetic field orientation produce correspondingly sudden changes in the wave amplitudes. Statistically, the wave amplitudes decrease continuously with increasing θ xB .