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Nonlinear tearing mode study using the almost ideal magnetohydrodynamics (MHD) constraint

Conference ·
DOI:https://doi.org/10.1063/1.872942· OSTI ID:334077
;  [1];  [2]
  1. Univ. of Wisconsin, Madison, WI (United States)
  2. General Atomics, San Diego, CA (United States)
The tearing mode is an important resistive magnetohydrodynamics (MHD) mode. It perturbs the initial equilibrium magnetic flux surfaces through magnetic field line reconnection to form new flux surfaces with magnetic islands. In the study of the tearing mode, usually the initial equilibria are one dimensional with two ignorable coordinates and the perturbed equilibria are two dimensional with one ignorable coordinate. The tearing mode can be linearly unstable and its growth saturates at a fine amplitude. The neoclassical tearing mode theory shows that the mode can be nonlinearly driven by the bootstrap current even when it is linearly stable to the classical tearing mode. It is important to study the nonlinear behavior of the tearing mode. As an intrinsically nonlinear approach, the use of the almost ideal MHD constraint is suited to study the nonlinear properties of the tearing mode. In this paper, as a validation of the method, the authors study two characteristics of the tearing mode using the almost ideal MHD constraint: (1) the linear stability condition for the initial one dimensional equilibrium; and (2) the final saturation level for the unstable case. In this work, they only consider the simplest case where no gradient of pressure or current density exists at the mode resonant surface.
Research Organization:
Univ. of Wisconsin, Center for Plasma Theory and Computation, Madison, WI (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
FG02-92ER54139
OSTI ID:
334077
Report Number(s):
CONF-9803121--PROC.; ON: DE99001004
Country of Publication:
United States
Language:
English