Application timing control of the vertical field an initial phase shell-less tokamak plasma

The small tokamak HAMANA-T does not have an electricity conductive shell, therefore, the vertical magnetic field for equilibrating quasi-steady plasma is applied simultaneously with plasma formation, and controls plasma position. The application of an excessively strong magnetic field due to delayed timing and the inaccuracy of plasma position control caused by toroidal magnetic field signal may occur. The authors detected the weak discharge light emission at the time of plasma formation with a photomultiplier, and generated immediately the pulses for timing magnetic field application. As the result, magnetic field was applied synchronously with plasma formation and stably. The process of plasma growth and the quantity of luminescence are explained. The HAMANA-T is composed of the torus vacuum vessel made of stainless steel, 20 toroidal magnetic coils which are so arranged as to surround it, the primary windings of the current transformer arranged above and below the vacuum vessel, vertical and horizontal magnetic coils and exhaust system. The generation of plasma-synchronous pulses and the result of functioning are reported. (K.I.)