Effect of the curvature and the β parameter on the nonlinear dynamics of a drift tearing magnetic island

Abstract

We present numerical simulation studies of 2D reduced MHD equations investigating the impact of the electronic β parameter and of curvature effects on the nonlinear evolution of drift tearing islands. We observe a bifurcation phenomenon that leads to an amplification of the pressure energy, the generation of E × B poloidal flow and a nonlinear diamagnetic drift that affects the rotation of the magnetic island. These dynamical modifications arise due to quasilinear effects that generate a zonal flow at the onset point of the bifurcation. Our simulations show that the transition point is influenced by the β parameter such that the pressure gradient through a curvature effect strongly stabilizes the transition. Regarding the modified rotation of the island, a model for the frequency is derived in order to study its origin and the effect of the β parameter. It appears that after the transition, an E × B poloidal flow as well as a nonlinear diamagnetic drift are generated due to an amplification of the stresses by pressure effects. PACS numbers: 52.30.Cv, 52.35.Py, 52.35.Ra, 52.55.Fa (Some figures in this article are in colour only in the electronic version)

Cite this paper

@inproceedings{Muraglia2017EffectOT, title={Effect of the curvature and the β parameter on the nonlinear dynamics of a drift tearing magnetic island}, author={Magali Muraglia and Olivier Agullo and M. Yagi and Sadruddin Benkadda and Kimitaka Itoh and Abhijit Sen}, year={2017} }