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arXiv · 1510.01945

Linear gyrokinetic particle-in-cell simulations of Alfven instabilities in tokamaks

A. Biancalani·A. Bottino·S. Briguglio·A. Koenies·Ph. Lauber·A. Mishchenko·E. Poli·B. D. Scott·F. Zonca
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Abstract

The linear dynamics of Alfven modes in tokamaks is investigated here by means of the global gyrokinetic particle-in-cell code NEMORB. The model equations are shown and the local shear Alfven wave dispersion relation is derived, recovering the continuous spectrum in the incompressible ideal MHD limit. A verification and benchmark analysis is performed for continuum modes in a cylinder and for toroidicity-induced Alfven Eigenmodes. Modes in a reversed-shear equilibrium are also investigated, and the dependence of the spatial structure in the poloidal plane on the equilibrium parameters is described. In particular, a phase-shift in the poloidal angle is found to be present for modes whose frequency touches the continuum, whereas a radial symmetry is found to be characteristic of modes in the continuum gap.

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A. Biancalani, A. Bottino, S. Briguglio, A. Koenies, Ph. Lauber, A. Mishchenko, E. Poli, B. D. Scott, F. Zonca. 2015-10-07. Linear gyrokinetic particle-in-cell simulations of Alfven instabilities in tokamaks. https://doi.org/10.1063/1.4939803

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