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To the Interchange Instability Criterion in the Magnetosphere in the Presence of Velocity Shear
Author(s) -
Khazanov George V.,
Krivorutsky Emanuel N.,
Chen Margaret W.,
Lemon Colby L.
Publication year - 2020
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028172
Subject(s) - wkb approximation , physics , instability , plasma , magnetohydrodynamic drive , two stream instability , wavelength , magnetosphere , mechanics , magnetohydrodynamics , excitation , shear (geology) , classical mechanics , computational physics , optics , quantum mechanics , materials science , composite material
In this paper, we address the issue of interchange instability excitation criterion in the magnetospheric plasma in the presence of the velocity shear using a magnetohydrodynamic approach. We conducted our analysis for the arbitrary β plasma configuration using a WKB approximation for wavelengths, λ , much smaller than the characteristic plasma inhomogeneity scale, L , and found two branches of waves. These two wave branches can exist due to the plasma velocity shear and one branch can be unstable for arbitrary angles between the plasma entropy parameter and magnetic flux tube volume gradients. The implications of these results for magnetospheric physics as well as comparison of our results with corresponding analysis of other authors are discussed.