Pulsed high power source for screw pinch device

Design and construction of a pulsed high power capacitor bank system for a thermonuclear fusion plasma experimental machine are described. The mission of TPE-2 is to produce a plasma of more than 100 eV in temperature and 10% in beta value, and to confine it for several hundreds microsec. The designed coil current is 1-5 MA in peak value, a few microsec in rising time and 1 ms in pulse length. In order to satisfy the above requirement, the energy of the capacitor bank exceeds 1 MJ and the inductance for bank system must be minimized. A high voltage capacitor bank of low inductance and a new idea of power crowbar system must be developed. A low inductance and high energy density capacitor unit, and a start gap switch with low jitter time were successfully developed after some trial manufacturing procedures. While, to maintain the reliability and reproducibility in operating the bank system, a monitoring system was newly developed. After the installation of switch monitoring system, the ratio of abnormally operated switches decreased to 1/5 owing to the effect of fast detection of miss operated switches. Also a new protection system against an accidental short-circuiting of bank system was developed. These two systems enabled to operate the bank system very stably and safely. The capacitor bank system was constructed and connected to load assembly of TPE-2. TPE-2 has been operated stably for over ten years and for more than 18,000 shots, which is the designed life time of the bank system. A plasma of 400 eV in maximum temperature and 14% in maximum beta value are produced and sustained for 800 microsec. These values are mainly due to the successful development of the pulsed high power capacitor bank system. (J.P.N.). 113 refs