Existence of Weakly Damped Kinetic Alfven Eigenmodes in Reversed Shear Tokamak
Authors: N. N. Gorelenkov
Abstract:
A kinetic theory of weakly damped Alfven Eigenmode (AE) solutions strongly interacting with the continuum is developed for tokamak plasmas with reversed magnetic shear. We show that the ideal MHD model is not sufficient for the eigenmode solutions if the standard causality condition bypass rule is applied. Finite Larmor radius effects are required, which introduce multiple kinetic subeigenmodes and collisionless radiative damping. The theory explains the existence of experimentally observed Alfvenic instabilities with frequencies sweeping down and reaching their minimum (bottom).
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Submitted to: Physical Review Letters
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