Shaping of output current rise time on 1 MA-LTD cavity

For the special need of wide variety of current waveforms during the magnetically driven isentropic compression experiment, this paper describes experiments that can shape the output current rise time on a refurbished 1.0 MV linear transformer driver(LTD) cavity. Forty-eight switches were divided into four groups, and each group of switches were triggered by one high voltage cable. Three sets of trigger cables with different length were conducted. The experimental results show that 0~100% rise time of output current can increase to 436.0 ns compared with 301.2 ns when all the switches are triggered simultaneously. However, the peak current will decrease from 294.0 kA to 210.2 kA with initial charge voltage of 32 kV. The closing time of forty switches were achieved by using fiber diagnostics system which could measure the switch optic signal during the discharge state. Based on the closing time of forty switches acquired in the experiment, the circuit model of 1 MA-LTD cavity was constructed in PSpice. The influence of the brick that has been triggered early in LTD cavity to other bricks was analyzed. This preliminary experiment results show that the LTD cavity can shape the output pulse with the aid of different trigger sequence.