Anomalous transport by magnetohydrodynamic Kelvin-Helmholtz instabilities in the solar wind-magnetosphere interaction

Journal Article · Wed Feb 01 04:00:00 EST 1984 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA089iA02p00801· OSTI ID:7101928

Miura, A

A magnetohydrodynamic simulation of Kelvin-Helmholtz instabilities in a compressible plasma has been performed for parallel (v/sub 0/parallelB/sub 0/) and (v/sub 0/perpendicularB/sub 0/) configurations, modeling high-latitude (or downstream flanks) and dayside low-latitude magnetospheric boundaries. In the parallel configuration, a super-Alfvenic and transsonic shear flow (with 24), the instability develops into a more turbulent state and the initial parallel shear flow develops into small eddies, which strongly twist, compress, and hence amplify the magnetic field by a dynamo action with an amplification factor M/sub A//2. In the nonlinear stage, however large the initial Alfven Mach number M/sub A/ may be, the magnetic field, amplified and twisted by the hydromagnetic flow vortices, eventually reacts back upon the flow evolution, and the flow vortices into smaller scale structures. In the transverse configuraion, for a fast magnetosonic Mach number M/sub f/( = V/sub 0//(c/sub s//sup 2/+v/sub A//sup 2/)/sup 1/2/) greater than a critical Mach number, the instability leads to the formation of a fast shock discontinuity from an initially subfast shear flow.

• Research Organization: Institute of Geophysics and Planetary Physics, University of California, Los Angeles
• OSTI ID: 7101928
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 89:A2; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPRESSIBLE FLOW
DIFFUSION
EARTH ATMOSPHERE
FLUID FLOW
FLUID MECHANICS
HELMHOLTZ INSTABILITY
HYDRODYNAMICS
INSTABILITY
MACH NUMBER
MAGNETOHYDRODYNAMICS
MAGNETOSPHERE
MECHANICS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA SIMULATION
SHEAR
SIMULATION
SOLAR ACTIVITY
SOLAR WIND
TURBULENCE
VELOCITY
VISCOUS FLOW
VORTEX FLOW