Development of inertial confinement fusion research system of high power laser. Project at Osaka University

This paper is described on the development of an inertial confinement fusion research system, performed at Osaka University. The four beam, glass laser system (Gekko No. 4) was constructed in 1977, and the obtained output power was 2 kJ. A CO₂ laser (Rekko No. 8) has been constructed. The designed output power is 10 kJ. The S/N ratio of pulses is more than 10⁶. While the development of Rekko 8, high voltage - high current technique was developed. A high speed parallel switching type Marx power source, of which the output power was 120 kJ, was constructed. The take-out efficiency of cumulative energy was 80 percent of stored energy. Impulse compression experiments were performed with the short pulse laser, and the conditions of producing thermo-nuclear fusion were investigated. The computer simulation technique was used for the development of pellet targets for nuclear fusion and the analysis of experimental results. The mechanism of laser energy absorption was studied. The ion temperature in the plasma compression experiment reached 6 keV. The strong compression at the center of targets was observed. A project for attaining the break-even of fusion energy is in progress. Construction of a laser system with output power of 20 kJ is the first step of the project. Then, an energy driver with output power of 100 kJ will be constructed. (Kato, T.)