Kelvin-Helmholtz instability for supersonic shear flow at the magnetospheric boundary

Journal Article · Tue May 01 00:00:00 EDT 1990 · Geophysical Research Letters (American Geophysical Union); (USA)

DOI:https://doi.org/10.1029/GL017i006p00749· OSTI ID:6608633

Miura, Akira ^[1]

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1. Univ. of Tokyo (Japan)

It is demonstrated by means of a MHD simulation that a finite thick velocity shear layer with super-Alfvenic velocity jump is unstable to the Kelvin-Helmholtz (KH) instability no matter how large the sonic Mach number, a result suggesting that the tail flank boundary is unstable to the KH instability. For supersonic shear flow the unstable mode becomes damped-oscillatory in the magnetosheath. For both subsonic and supersonic shear flows, the energy flux density into the magnetosphere by the KH instability is large enough to replenish the plasma in the low latitude boundary layer with the tailward flow kinetic energy of observed intensity. A significant fraction of the energy flux density can reach deeper into the magnetosphere and its intensity is comparable to an energy flux density required for excitation of a ULF wave in the magnetosphere.

• OSTI ID: 6608633
• Journal Information: Geophysical Research Letters (American Geophysical Union); (USA), Vol. 17:6; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOUNDARY LAYERS
HELMHOLTZ INSTABILITY
EARTH MAGNETOSPHERE
KINETIC ENERGY
MACH NUMBER
MAGNETOHYDRODYNAMICS
MAGNETOPAUSE
MAGNETOSHEATH
MAGNETOTAIL
MATHEMATICAL MODELS
NONLINEAR PROBLEMS
PLASMA
SHEAR
SIMULATION
SUBSONIC FLOW
SUPERSONIC FLOW
EARTH ATMOSPHERE
ENERGY
FLUID FLOW
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
LAYERS
MECHANICS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
VELOCITY
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena