Synchronous Trigger Technology and Discharge Characteristics of Multiparallel Gas Switches Based on Parallel Plate Transmission Lines

This article proposes a gas switch with a low inductance (31 nH), a wide operating coefficient (≥50%), a rapid breakdown (< 100 ns), and a high intensity of current (532 kA/7.8 C). We also design a synchronous trigger system for discharging multiparallel switches while ensuring significant scalability and low cost. The maximum amplitude of the outputs of 16 pulses under high-resistance loads was 77.1 kV/14 ns (10%–90% rise time). Following this, we built a 200-kJ compact pulsed power device by using parallel plate transmission lines. This device can reduce the overall inductance by 14% compared with the previous generation of devices. We also investigated the factors influencing synchronous discharge as well as the conditions for the synchronous discharge of 16 gas switches in parallel. At an operating voltage of 70 kV, the maximum amplitude of the short-discharge current was 5.5 MA (deviation was less than 3%) and the shortest rise time was around $1 ~\mu \text{s}$ (10%–90% rise time). The stable operation of the device is important for physics research on the load.

I. Introduction

The compact pulsed-power device built by using capacitors, gas switches, transmission lines, and loads has the characteristics of low inductance, high peak current, and high di/dt. It is widely used in the applications of pulsed power, including isentropic compression, exploding wire phenomena, and pulse-high magnetic fields [1], [2], [3], [4], [5]. This device comprises a number of basic units connected in parallel to the load through parallel plate transmission lines to achieve low inductance. Each basic unit is composed of a capacitor and a switch. The load obtains the pulse current with the maximum efficiency and the shortest rise time through the synchronous discharge of multiparallel switches [6]. However, there is hardly any transitional isolation time between the parallel gas switches due to the structural design of the device, where this leads to later breakdown switches affecting earlier ones, such that the voltage across the former decreases rapidly. The breakdown of the later switches is thus inhibited, and they may fail to conduct [7], [8]. In general, the relevant parameters of the capacitors (excluding the parallel gas switches), the parallel plate transmission lines, and the loads can be determined at the outset of the design of the device. Therefore, the operating characteristics of parallel gas switches are important and require a detailed evaluation.