Axisymmetric MHD equilibria with isothermal toroidal mass flow by variational steepest descent moments method

An energy principle is constructed for an axisymmetric system such that its variation with respect to an artificial time parameter t is demonstrated to yield the components of the magnetohydrodynamic (MHD) force F=j*B- Del p- rho _M(V. Del )V when V is only toroidal. An accelerated steepest descent method is applied to the Fourier moments of these MHD forces in an inverse flux coordinate representation to reach a minimum energy state that corresponds to an MHD equilibrium with isothermal toroidal mass flow. Applications to a JET Tokamak configuration show the outward displacement of the pressure surfaces away from the flux surfaces induced by the plasma rotation. For fixed global and peak values of the total plasma energy content (thermal pressure plus directed flow), however, the position of the magnetic axis does not shift with the rotation.