Compact Toroidal Plasma with Toroidal and Poloidal Magnetic Fields

Compact toroidal plasma has been experimentally obtained in a drum-type copper vessel on injecting an annular plasma stream from a magnetized plasma gun. Toroidal and poloidal magnetic fields, B t and B p , of the plasma toroid show a typical exponential decay with 110 µs and no MHD instability is observed. Experimental data of B t and B p configuration for long confinement are described fairly well by the model, which is the fundamental-mode state of the minimum energy force-free equilibrium estimated from the low- β limit Grad-Shafranov equation. The configuration of the stable plasma is hence fully-determined by the metal vessel geometry.