Streaming sausage, kink and tearing instabilities in a current sheet with applications to the Earth's magnetotail

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA093iA07p07354· OSTI ID:6952767

Lee, L C; Wang, S; Wei, C Q; Tsurutani, B T

In this paper, the growth rate and eigenmode structures of the streaming sausage and kink instabilities in a current sheet with a super-Alvenic flow are studied. Based on the linearized compressible profiles of the fastest growing mode which is either the streaming sausage mode or kink mode. The streaming sausage and kink instabilities, similar to the Kelvin-Helmholtz instability, are caused by the sheared plasma flow. The results show that for V/sub 0//sub m/ = 2 V/sub A//sub infinity/ the sausage mode grows faster than the kink mode when ..beta../sub infinity/<1.5. When ..beta../sub infinity/>1.5, the streaming kink instability has a higher growth rate. Here V/sub A//sub infinity/ is the Alfven velocity and ..beta../sub infinity/ is the ratio between the plasma and magnetic pressures far away from the current layer, and V/sub 0//sub m/ is the maximum velocity of plasma flow at the current sheet. In addition, an analytical dispersion equation is obtained for an ideal four-layer model of the current sheet in the incompressible limit. In the presence of a finite resistivity, the mixed sausage-tearing mode or the streaming tearing mode may be excited, which leads to the formation of plasmoids in the magnetotail. As an application to the Earth's magnetotail, where super-Alfvenic plasma flows are observed in the plasma sheet and ..beta../sub infinity/approx. =0.1--0.3 in the lobes, it is suggested that the streaming sausage and streaming tearing instabilities may occur in the magnetotail.

• Research Organization: Geophysical Institute and Department of Physics, University of Alaska, Fairbanks, Alaska
• OSTI ID: 6952767
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 93:A7; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DISPERSION RELATIONS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EQUILIBRIUM
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
INSTABILITY GROWTH RATES
KINK INSTABILITY
MAGNETOHYDRODYNAMICS
MAGNETOTAIL
MECHANICS
MHD EQUILIBRIUM
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SAUSAGE INSTABILITY
SHEAR
TEARING INSTABILITY