Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

Halpern, Federico D.; Lütjens, Hinrich; Luciani, Jean-François
October 2011
Physics of Plasmas;Oct2011, Vol. 18 Issue 10, p102501
Academic Journal
The cycling dynamics of the internal kink mode, which drives sawtooth oscillations in tokamak plasmas, is studied using the three dimensional, non-linear magnetohydrodynamic (MHD) code XTOR-2F [H. Lütjens and J.-F. Luciani, J. Comput. Phys. 229, 8130 (2010)]. It is found that sawtooth cycling, which is characterized by quiescent ramps and fast crashes in the experiment, can be recovered in two-fluid MHD provided that a criterion of diamagnetic stabilization is fulfilled. The simulation results indicate that diamagnetic effects alone may be sufficient to drive sawteeth with complete magnetic reconnection in high temperature Ohmic plasmas.


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