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Observations of density fluctuations in Earth's magnetosheath with Geotail and Wind spacecraft
Author(s) -
Seon J.,
Park S. M.,
Min K. W.,
Frank L. A.,
Paterson W. R.,
Ogilvie K. W.
Publication year - 1999
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 - 10.1029/1999gl900131
Subject(s) - magnetosheath , magnetopause , physics , solar wind , bow shock (aerodynamics) , geophysics , oscillation (cell signaling) , plasma , amplitude , astrophysics , computational physics , magnetosphere , substorm , shock wave , atmospheric sciences , mechanics , optics , quantum mechanics , biology , genetics
Large fluctuations of plasma densities in the earth's flank‐side magnetosheath (local times 1500–1700) are examined. The characteristics of the fluctuations are large amplitudes (ΔN/N ∼ 1), long oscillation periods (T ∼ 30 m) and anti‐ correlation between the plasma densities and magnetic field strengths. The variations of the solar wind plasma densities are negligible, whereas considerable fluctuations are found for the solar wind magnetic fields. Two possibilities are considered for the density fluctuations: 1) repeated traversals of the plasma depletion layer and the standing slow‐mode waves near the magnetopause and 2) convected slow‐mode waves generated at the earth's bow shock. Temperature anisotropy and density profile as expected from the repeated traversals are not confirmed with the observations. Based on the consideration that the present observations occur in the flanks where plasma flows are largely tangential to the magnetopause, we propose that the convected slow‐mode waves play a role in the generation of the density fluctuations.