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Can substorm expansive phase effects and low frequency Pc magnetic pulsations be attributed to the same source mechanism?
Author(s) -
Rostoker Gordon,
Samson John C.
Publication year - 1984
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/gl011i003p00271
Subject(s) - substorm , plasma sheet , geophysics , instability , boundary layer , earth's magnetic field , physics , geology , expansive , plasma , magnetic field , mechanics , magnetosphere , compressive strength , quantum mechanics , thermodynamics
Geomagnetic pulsations and magnetospheric substorms are often treated as separate topics in the literature. These phenomena do, however, share common properties including spatial localization and characteristic propagation velocities. In this paper we discuss the possibility that both phenomena originate from Kelvin‐Helmholtz instabilities at the interface between the low latitude boundary layer/boundary layer plasma sheet and the central plasma sheet. The variations in horizontal scale size and azimuthal velocities found in ground‐based observations of Pc 4,5, Ps 6 and westward travelling surges can be explained by variations in the shear flow and width of the regions where the instability occurs.