Effects of finite Larmor radius on equilibria with flow in reduced two-fluid models

摘要

Finite Larmor radius (FLR) effects on magnetohydrodynamic (MHD) equilibria with flow are studied in reduced two-fluid models for high-beta tokamaks. Two different orderings for the flow velocity, comparable to the poloidal Alfven velocity and comparable to the poloidal sound velocity, are considered. For a poloidal-Alfvenic flow, the two-fluid equilibrium equations are shown to have a singularity that is shifted by the gyroviscous cancellation from the Alfven singularity. For a poloidal-sonic flow, a reduced set of equilibrium equations that includes higher-order terms is derived. Numerical analysis shows that there are regular solutions for the two-fluid model with FLR that are singular for the single-fluid and Hall MHD models. The dependence of the equilibria on the sign of the E x B flow compared to that of the ion diamagnetic flow can be examined with the analytical expression for the shifts of the maximum values of the pressure and the ion stream function from the magnetic axis.