Energy principle for resistive perturbations in Tokamaks

An energy principle has been found for all resistive perturbations of a circular plasma cylinder in the Tokamak scaling (kr approximately=B theta /B z approximately= epsilon ). It allows stability to be determined independently of the resistive scaling because resistivity is taken to be finite. The inclusion of FLR effects and viscosity would only reduce the growth rates. Using simple test functions near the resonances always leads to instability. Estimates of growth rates can be made, these being only rough if FLR effects dominate.