Magnetic error field effects on magnetic island formation in a tokamak plasma
- Univ. of Wisconsin, Madison, WI (United States)
Helically resonant magnetic error fields are expected to generate magnetic islands in plasmas-islands which at a minimum can reduce plasma confinement or can ultimately lead to plasma disruptions. To simulate the effect of error fields on the dynamics of resistive MHD tearing modes, a static magnetic field perturbation has been added to the boundary conditions of a toroidal, neoclassical reduced MHD model/simulation code. The static field perturbation is also used to assess the threshold destabilization of neoclassical MHD tearing modes. The model consists of a set of incompressible, reduced-MHD equations for the poloidal flux {psi}, the velocity stream function {phi}, and the plasma pressure p, which have been implemented in a reduced version of the fully three dimensional, toroidal, initial value FAR code. The model includes neoclassical viscous-stress effects (V {circ} {pi}) based on analytical kinetic closures and an anisotropic pressure diffusivity. Simulation results with this static perturbation result are compared with analytic predictions based on resistive tearing stable profiles in slab geometry of 5 dynamical growth phases that describe the mode dynamics from the current sheet formation to the Rutherford island growth regime. However in beam-driven plasmas, strong plasma rotation is expected to provide a viscous damping which can partially shield the effect of the error field. To simulate such an effect, a rotating magnetic field perturbation has also been added to the model. Results based on this dynamic field perturbation will be presented.
- DOE Contract Number:
- FG02-86ER53218
- OSTI ID:
- 489498
- Report Number(s):
- CONF-960354-; TRN: 97:011645
- Resource Relation:
- Conference: International Sherwood fusion theory conference, Philadelphia, PA (United States), 18-20 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of 1996 international Sherwood fusion theory conference; PB: 244 p.
- Country of Publication:
- United States
- Language:
- English
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