Infoscience

Conference paper

MHD properties in the core of ITER-like hybrid scenarios

MHD stability is studied in the frame of ITER like hybrid scenarios, characterized by weak reversed shear, with particular attention on ideal internal kink modes and infernal mode stability. Numerical simulations for ITER like equilibria, with hollow q profiles with an off axis minimum close to unity, were carried out using the 3-D equilibrium code ANIMEC, which showed the presence of a 3-D helical core [1] with the characteristics of a saturated internal kink mode. The internal kink perturbation has been investigated non-linearly using the XTOR code, in the ideal frame. A scan in the current was performed and it has been found that when the minimum of q is above the unity (low currents), the helical distorsion shows good agreement with the results provided by the 3-D ANIMEC simulations while for q(min) below 1 (high currents), XTOR gives a residual distorsion in contrast with the ANIMEC results. Moreover infernal mode stability in hybrid scenarios has been studied analytically extending the quasi-interchange model with the inclusion of resistive and both electron and ion diamagnetic effects. This enables us to investigate kinetic effects on plasma scenarios susceptible to saturated kink structures exhibited into ANIMEC simulations.

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