Kelvin-Helmholtz instabilities of supersonic/super-alfvenic shear layers

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6739677

Choudhury, S R

A number of space and astrophysical plasma configurations are characterized by velocity shear layers with a velocity change ..delta..v/sub z/ across a layer of thickness ..delta..x. This thesis examines the stability properties of finite-thickness compressible shear layers. Two different velocity profiles are investigated in detail using the analogy between the pressure perturbation and the bound and scattering wave states of the one-dimensional Schroedinger equation. By analytical and numerical methods, fairly complete contour maps were generated for the real and imaginary parts of the wave frequency as a function of the two free dimensionless parameters, the reduced Mach number, and the wavenumber. Two distinct regimes of instability are delineated. In one regime there are unstable standing waves which are analogous to the well-known Kelvin-Helmholtz warning instability of a vortex sheet (where v/sub z/(x) is a step function). In the second regime, there are unstable travelling wave modes that are absent in the case of a vortex sheet. The stability of finite-thickness, compressible, magnetized shear layers is also investigated numerically. Both the standing and travelling waves are found to occur. A formation is derived for investigating the stability of low temperature, collisionless shear layers in the presence of a magnetic field parallel to the macroscopic flow. The equations of kinetic theory are employed.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 6739677
• Country of Publication: United States
• Language: English

Related Subjects

640100* -- Astrophysics & Cosmology
657002 -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
DIFFERENTIAL EQUATIONS
EQUATIONS
HELMHOLTZ INSTABILITY
INSTABILITY
KINETIC EQUATIONS
LAYERS
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA WAVES
SCHROEDINGER EQUATION
SHEAR
SPACE
STANDING WAVES
STELLAR ATMOSPHERES
TRAVELLING WAVES
WAVE EQUATIONS