Tearing mode growth in a regime of weak magnetic shear
Abstract
The nonlinear growth for the m/n≥2 resistive tearing mode is studied in the case when the rational surface q(r0)=m/n falls in a regime of weak magnetic shear, q'(r0)≂0. The island width is determined self-consistently from the nonlinear, zero-helicity component of the perturbed magnetic flux that provides the local shear. It is found that the magnetic perturbation keeps growing exponentially in the nonlinear regime on a hybrid resistive-Alfvénic time scale, while the island width and the vorticity grow on a much slower time scale. Accordingly, much faster release of magnetic energy results for modes growing near minima of hollow q profiles.
- Publication:
-
Physics of Fluids
- Pub Date:
- May 1988
- DOI:
- 10.1063/1.866745
- Bibcode:
- 1988PhFl...31.1161R
- Keywords:
-
- Magnetic Field Configurations;
- Magnetohydrodynamic Waves;
- Shear Stress;
- Tearing Modes (Plasmas);
- Magnetic Field Reconnection;
- Magnetohydrodynamic Stability;
- Perturbation Theory;
- Reynolds Number;
- Vorticity;
- Plasma Physics