抄録
Ultra Low Aspect Ratio Tokamaks (ULART) are produced by using a negative-biased theta-pinch device. A slender conducting rod which plays a role of a toroidal field coil is newly installed along a geometrical center axis of the theta-pinch coil. The ULART is quickly formed for about 10μs by applying programmed current flows from three sets of fast banks and a slow bank to these coils and is sustained for about 100μs.
The plasma diagnosed from a magnetic probe array has a low aspect ratio A=1.1 and a poloidal surface with a high elongation ratio κ=10. The safety factor reaches about 30 near the separatrix edge when Ip=280kA flows in the plasma and Itfc=30kA in the conducting rod. A preliminary result on global MHD characteristics of the ULART is also given. The plasma behaves unstable to a vertical displacement and a toroidal n=1 mode. The amplitudes of these modes depend on the values of Itfc, and κ.
