Effects of liquid metal walls on equilibrium and stability in tokamaks

The liquid metal wall concept has received a great deal of attention recent ly because of its perceived advantages in addressing high heat flux, magnet ohydrodynamic (MHD) stability, and other related issues in advanced confine ment schemes. Despite its inherent and clear benefits, this concept also po ses potentially serious problems from the MHD equilibrium and stability poi nt of view. In particular, a liquid metal flow fast enough to stabilize res istive wall modes can also have adverse effects on the MHD equilibrium thro ugh its interaction with the background poloidal and toroidal fields. These deleterious effects can be large enough to effectively prevent any expecte d stabilization of the unstable MHD modes. (C) 2001 American Institute of P hysics.