Nonlinear Dynamics of Magnetic Islands Imbedded in Small-Scale Turbulence

Magali Muraglia (1) , Oliver Agullo (1) , Sadruddin Benkadda (1) , Xavier Garbet (2) , P. Beyer (3) , Abhijit Sen (4)

1 PIIM - Physique des interactions ioniques et moléculaires
2 CEA/DSM/DRFC - Association EURATOM-CEA
3 Equipe Dynamique des Systemes Complexes
4 Institute for plasma research

The nonlinear dynamics of magnetic tearing islands imbedded in a pressure gradient driven turbulence is investigated numerically in a reduced magnetohydrodynamic model. The study reveals regimes where the linear and nonlinear phases of the tearing instability are controlled by the properties of the pressure gradient. In these regimes, the interplay between the pressure and the magnetic flux determines the dynamics of the saturated state. A secondary instability can occur and strongly modify the magnetic island dynamics by triggering a poloidal rotation. It is shown that the complex nonlinear interaction between the islands and turbulence is nonlocal and involves small scales.

Mots clés: magnetic islands; interchange; turbulence; magnetized plasmas; MHD; simulation

Domaines: Physique des plasmas [physics.plasm-ph]

Magali Muraglia, Oliver Agullo, Sadruddin Benkadda, Xavier Garbet, P. Beyer, et al.. Nonlinear Dynamics of Magnetic Islands Imbedded in Small-Scale Turbulence. Physical Review Letters, 2009, 103, pp.145001. ⟨10.1103/PhysRevLett.103.145001⟩. ⟨hal-00578061⟩