Tokamak experiment in SPAC-II

A small scale tokamak type device named SPAC-II was constructed for the investigation of various problems in the confinement and heating of toroidal plasmas. In a tokamak mode experiment, plasma with the electron temperature of 180 eV is generated, when the plasma current is 18 kA and the safety factor q=3.9. The energy confinement time is about 200 µs which is consistent with the scaling law of (plasma radius)2×(poloidal field). The current density is estimated to be 4×102 Acm-2 for the parabolic distribution.