Abstract
We have developed railgun system since 1986 for the research on hyper-velocity impacts in space. The highest projectile velocity achieved in our institute is 3.7km/sec. Railgun used for the experiment is 95cm long, and the bore is 10mm square. Projectile is polycarbonate block around its mass is 1.0-2.0g. Power supply is 6mF capacitor bank. Total maximum energy is 300kJ. The power supply is constituted by 6 stage pulse forming network. The current wave form may be controlled by varying the inductor of pulse forming network. Higher current with shorter duration of discharge results in higher projectile velocity. This is due to two reasons. One reason is that energy supplied into the railgun increases with higher current. The other reason is that efficiency of the railgun also increases with higher current. The reason of higher efficiency with higher current is that the ratio of increase rate of projectile kinetic energy to energy supplied into the railgun for a unit time increases with higher current.
