A computational study of ion cyclotron frequency stabilization of the m=1 interchange mode in mirror geometry

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Abstract
A cylindrical plasma model is used to study the stabilizing effect of electromagnetic ion cyclotron frequency range (ICRF) waves on the m=1 magnetohydrodynamic interchange mode. The fast wave eigenmodes of the column and the near‐field antenna pattern are calculated numerically for a diffuse plasma profile when ω>Ωi. The resulting ponderomotive force and sideband contributions to global interchange stability are then determined using a rigid shift trial function. For far‐field stabilization it is verified that the direct ponderomotive and sideband contributions cancel exactly as the conducting wall supporting the fast wave eigenmode moves out to infinity. The near‐field stabilization effect is related numerically to the driven k∥ spectrum of the waves and their radial profiles. The numerical model is employed to calculate threshold ICRF wave amplitudes for the stabilization experiments in the Phaedrus tandem mirror [Phys. Rev. Lett. 5 1, 1955 (1983)].