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

M. Muraglia, O. Agullo, M. Yagi, S. Benkadda, P. Beyer, X. Garbet, S. I. Itoh, K. Itoh, A. Sen

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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.

Original languageEnglish
Article number055016
JournalNuclear Fusion
Volume49
Issue number5
DOIs
Publication statusPublished - Jul 6 2009

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All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Muraglia, M., Agullo, O., Yagi, M., Benkadda, S., Beyer, P., Garbet, X., ... Sen, A. (2009). Effect of the curvature and the β parameter on the nonlinear dynamics of a drift tearing magnetic island. Nuclear Fusion, 49(5), [055016]. https://doi.org/10.1088/0029-5515/49/5/055016