A Way for High-Voltage $\mu\hbox {s}$ -Range Square Pulse Generation

In this paper, a new way for high-voltage μs -range quasi-square pulse generation based on a ns source pulser and a chopping spark gap is introduced. The source pulser delivered high-voltage source pulse with front edge at ns range to the chopping gap, and the chopping gap chopped the long flat back edge of the source pulse, so that a quasi-square pulse was formed on a high-impedance load. The breakdown-delay characteristics of the chopping gap, which was the most important, were studied in detail. Results of the experiments showed that when the pulse voltage peaked by the first peaking gap was a little lower than or approximate to the breakdown voltage of the chopping gap, the chopping gap broke down at the back edge of the peaked pulse so that the breakdown-delay time can increase from 30 ns to several μs. The breakdown-delay time of chopping gap is confined to the flat top of the peaked pulse. By using this mechanism of breakdown delay, a quasi-square pulse with pulse width of 1.95 μs, amplitude of 55 kV, and front edge of 22 ns was produced on a 1.15-kΩ load. Repetitive chopping pulses at 0.2 Hz were provided to demonstrate the feasibility of the chopping gap. By contrast to the conventional chopping, four essential conditions were concluded. Based on these results, a controllable trigatron-type chopping gap system is introduced to ensure chopping stability. It provides an important new way for μs-range high-voltage square pulse generation.