Experimental study of current loss of a single-hole post-hole convolute on the QG I generator

The post-hole convolute (PHC), which is used to transport and combine the pulse power flux, is a key component in huge pulsed power generators. Current loss at the PHC is a challenging problem for researchers. To explore a method of reducing the current loss, a single-hole PHC was designed for experiments on the current loss on the Qiang Guang I generator. The experimental results showed that the current loss at the single-hole PHC is related to the distance l between the vicinity of the cathode hole and the surface of the downstream side of the post. Meanwhile, a single-hole PHC with a blob cathode hole transmitted current more effectively than the PHC with a circle cathode hole. The relative current loss at the single-hole PHC with the cathode coated with gold foil was about 30%–50% of that with the cathode coated with nickel and titanium foil. The gap closing speed was also obtained from the current waveforms in the experiments. The speed was 5.74–14.52 cm μs⁻¹ which was different from the classical plasma expansion velocity of 3 cm μs⁻¹.