Experimental Study of Plasmoid Formation and Transport by Means of Moving Magnetic Fields

摘要

Driven, steady-state, stable plasmoids have been generated in an external axial magnetic field by rotating magnetic fields. The plasma equilibrium was stable for any value of beta between zero and unity. The plasmoid was free-standing, Well removed from the RF antenna and the limiters. Limits to plasmoid stability have been investigated, and it was found that the antenna near-fields can effectively stabilize gross Magnetohydrodynamic modes through the RF ponderomotive force when the rotating field strength was higher than the value necessary for full field penetration. Decay of the driven diamagnetic current and thus the plasmoid has been investigated, and it was found that the resistive current decay was responsible for an induced azimuthal electric field producing the rapid, ion inertia limited E x B radial expansion. Keywords: Plasmoid; Stability; Equilibrium; Rotating fields. (JHD)