A drift-magnetohydrodynamical fluid model of helical magnetic island equilibria in the pedestals of H-mode tokamak plasmas
- Department of Physics, Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)
A drift-magnetohydrodynamical (MHD) fluid model is developed for an isolated, steady-state, helical magnetic island chain, embedded in the pedestal of a large aspect ratio, low-beta, circular cross section, H-mode tokamak plasma, to which an externally generated, multiharmonic, static magnetic perturbation whose amplitude is sufficiently large to fully relax the pedestal toroidal ion flow is applied. The model is based on a set of single helicity, reduced, drift-MHD fluid equations which take into account neoclassical poloidal and toroidal flow damping, the perturbed bootstrap current, diamagnetic flows, anomalous cross-field diffusion, average magnetic-field line curvature, and coupling to drift-acoustic waves. These equations are solved analytically in a number of different ordering regimes by means of a systematic expansion in small quantities. For the case of a freely rotating island chain, the main aims of the calculation are to determine the chain's phase velocity, and the sign and magnitude of the ion polarization term appearing in its Rutherford radial width evolution equation. For the case of a locked island chain, the main aims of the calculation are to determine the sign and magnitude of the polarization term.
- OSTI ID:
- 21378032
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 6; Other Information: DOI: 10.1063/1.3432720; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BOOTSTRAP CURRENT
HELICITY
H-MODE PLASMA CONFINEMENT
MAGNETIC ISLANDS
MAGNETOHYDRODYNAMICS
PLASMA
PLASMA DRIFT
POLARIZATION
SOUND WAVES
TOKAMAK DEVICES
CLOSED PLASMA DEVICES
CONFINEMENT
CURRENTS
ELECTRIC CURRENTS
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC CONFINEMENT
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
PARTICLE PROPERTIES
PLASMA CONFINEMENT
THERMONUCLEAR DEVICES