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Active Control of Alfvén Eigenmodes by Externally Applied 3D Magnetic Perturbations
J Gonzalez-Martin1,2, M Garcia-Munoz3, J Galdon-Quiroga3
1Department of Mechanical Engineering and Manufacturing, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville, Spain.
Abstract:
The suppression and excitation of Alfvén eigenmodes have been experimentally obtained, for the first time, by means of externally applied 3D perturbative fields with different spatial spectra in a tokamak plasma. The applied perturbation causes an internal fast-ion redistribution that modifies the phase-space gradients responsible for driving the modes, determining, ultimately their existence. Hybrid kinetic-magnetohydrodynamic simulations reveal an edge resonant transport layer activated by the 3D perturbative field as the responsible mechanism for the fast-ion redistribution. The results presented here may help to control fast-ion driven Alfvénic instabilities in future burning plasmas with a significant fusion born alpha particle population.
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