Stabilization of Resistive Wall Mode Due to Shear Alfvén Resonance in a Cylindrical Plasma with a Uniform Longitudinal Flow

抄録

Resistive wall mode (RWM) is studied in a cylindrical plasmawith a uniform longitudinal plasma flow.In order to simplify the analysis, two steps current profile model is employed with a constant current densityj₀ for the inner region 0 ≤ r ≤ a₀ and a constant current density j₁ for the outer region a₀ ≤ r ≤ a.Also the resistive shell is assumed sufficiently thin.Current profiles from peaked ones to hollow ones are simulated by changing the ratio j₁ / j₀.Based on the incompressible MHD model, it is shown that RWM can be stabilized by adjusting the resistive wall position, when the shear Alfvén resonance appears inside the plasma column, with the increase of the uniform flow velocity.In this case the free energy destabilizing the RWM is absorbed in the plasma column through the shear Alfvén resonance.However, except when the RWM is close to the marginal state without a plasma flow, the flow velocity for stabilization is comparable to the sound velocity.