Potential Control and Flow Generation in a Toroidal Internal-Coil System -- a New Approach to High-beta Equilibrium --

Potential control and flow generation have been studied on the Proto-RT device that is equipped with an internal ring coil producing a stationary magnetic field. Biasing the surface of the internal coil, the radial electric field is controlled. Supersonic flow has been generated when the plasma is negatively biased. The present experiment is limited in a low-density (~ 10 m) regime, and hence, only electrostatic effects dominate the structure and stability. Higher density plasma will be produced in a new device Mini-RT that has a super-conducting levitated internal ring. When the flow velocity becomes comparable to the Alfven speed, the hydrodynamic pressure can produce a new type of high-beta (diamagnetic) equilibrium, so-called “double Beltrami (DB) state”. Recent theory predicts “self-organization” of a DB state that may have Lyapunov stability. This regime is the target of the new device Mini-RT that is equipped with a super-conducting levitated internal coil system.