Effects of Liquid Metal Walls on Equilibrium and Stability in Tokamaks

Liquid metal wall concept has received a great deal of attention recently because of its perceived advantages in addressing high heat flux, magnetohydrodynamic (MHD) stability, and other related issues in advanced confinement schemes. Despite its inherent and clear benefits, this concept also poses potentially serious problems from the MHD equilibrium and stability point of view. In particular, a liquid metal flow strong enough to stabilize resistive wall modes can also have adverse affects on the MHD equilibrium through its interaction with the background poloidal and toroidal fields. These deleterious effects can be large enough to mitigate any expected stabilization of the unstable MHD modes.