Instabilities and vortex dynamics in shear flow of magnetized plasmas
Gradient-driven instabilities and the subsequent nonlinear evolution of generated vortices in sheared E {times} B flows are investigated for magnetized plasmas with and without gravity (magnetic curvature) and magnetic shear by using theory and implicit particle simulations. In the linear eigenmode analysis, the instabilities considered are the Kelvin-Helmholtz (K-H) instability and the resistive interchange instability. The presence of the shear flow can stabilize these instabilities. The dynamics of the K-H instability and the vortex dynamics can be uniformly described by the initial flow pattern with a vorticity localization parameter {epsilon}. The observed growth of the K-H modes is exponential in time for linearly unstable modes, secular for marginal mode, and absent until driven nonlinearly for linearly stable modes. The distance between two vortex centers experiences rapid merging while the angle {theta} between the axis of vortices and the external shear flow increases. These vortices proceed toward their overall coalescence, while shedding small-scale vortices and waves. The main features of vortex dynamics of the nonlinear coalescence and the tilt or the rotational instabilities of vortices are shown to be given by using a low dimension Hamiltonian representation for interacting vortex cores in the shear flow. 24 refs., 19 figs., 1 tab.
- Research Organization:
- Texas Univ., Austin, TX (USA). Inst. for Fusion Studies
- Sponsoring Organization:
- DOE/ER; National Science Foundation (NSF)
- DOE Contract Number:
- FG05-80ET53088
- OSTI ID:
- 7055389
- Report Number(s):
- DOE/ET/53088-418; IFSR-418; ON: DE90009448; TRN: 90-010526
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FLUID FLOW
VORTICES
PLASMA
HELMHOLTZ INSTABILITY
ELECTRON DENSITY
EQUATIONS OF MOTION
GRAVITATIONAL FIELDS
MAGNETIC CONFINEMENT
MAGNETIC FIELDS
NONLINEAR PROBLEMS
PRESSURE GRADIENTS
SHEAR PROPERTIES
CONFINEMENT
DIFFERENTIAL EQUATIONS
EQUATIONS
INSTABILITY
MECHANICAL PROPERTIES
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA CONFINEMENT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
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