Streaming tearing instability in the current sheet with a super-Alfvenic flow

Journal Article · Wed Jun 01 04:00:00 EDT 1988 · Phys. Fluids; (United States)

OSTI ID:5265768

Wang, S; Lee, L C; Wei, C Q

The tearing instability in a current sheet, which has a sub-Alfvenic or super-Alfvenic plasma flow in the current layer, is investigated based on the linearized compressible magnetohydrodynamic (MHD) equations. An initial-value method is employed to obtain the linear growth rate and eigenmode profiles of the fastest growing mode. The results show that for a sub-Alfvenic plasma flow parallel to the neutral sheet, the growth rate of the tearing instability is only slightly larger than that of the pure tearing mode without the flow. On the other hand, a large increase in the growth rate of the most unstable mode is observed, when the streaming speed V/sub 0//sub m/ in the central region of the current sheet increases above a critical speed V/sub C/approx. =1.2V/sub A//sub infinity/. Here V/sub A//sub infinity/ is the Alfven speed far away from the current layer. This study shows that when the electric resistivity eta is zero, the sausage mode is excited because of a super-Alfvenic plasma flow parallel to the current sheet. This flow-induced sausage mode is called the streaming sausage mode. In the presence of a finite resistivity, the streaming sausage mode becomes a mixed sausage--tearing mode, because of the presence of magnetic field line reconnections in the current sheet. This mixed sausage--tearing mode, or simply the streaming tearing mode, has a high growth rate, ..gamma..approx. =0.1tau/sup -1//sub A/, where tau/sub A/ is the Alfven transit time across the current layer.

• Research Organization: Geophysical Institute and Department of Physics, University of Alaska, Fairbanks, Alaska 99775-0800
• OSTI ID: 5265768
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 31:6; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
COMPRESSIBLE FLOW
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EXPANSION
FLUID FLOW
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INSTABILITY
INSTABILITY GROWTH RATES
MAGNETOHYDRODYNAMICS
MECHANICS
PLASMA EXPANSION
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA SHEET
SAUSAGE INSTABILITY
TEARING INSTABILITY