Ding Wenjing, Feng Jinjun, Zhang Ming, Yang Hongfei
Vacuum Electronics Research Institute, Beijing 100015, China
Email: fengjinjun@tsinghua.org.cn
Abstract text. The pseudospark switch works in the left branch of Paschen curve with low gas pressure, which has the advantage of short electrode breakdown time (<10ns), large pulse current (>100kA), and long lifetime, etc. High pulse repetition frequency (PRF) pseudospark switch has important applications in food processing, sewage treatment, high energy laser system, sonar syste, and other fields, the pseudospark switch with a PRF of kHz-level is needed. This paper focuses on the pseudospark switch with double-pulse trigger structure, and the corresponding relationship between the two trigger voltages and current is calculated respectively, and the influence of the two pulses on the trigger process is analyzed. Then the pseudospark switch with this structure is tested with the anode voltage of 10kV for different voltage and gas pressure. The results show that the minimum trigger voltage is only 100V, and the switch can work stably with high repetition frequency.
Introduction: In engineering practice and scientific research, the increasing development of pulse power technology also requires the subsequent progress of switching devices, especially in the field of high PRF has urgent application needs and huge space for development, such as in the military field, for underwater communication and underwater confrontation, the need for 10 kHz to 100 kHz with sonic high repetition frequency switches. High power and high repetition frequency switches of GW class kHz are also required in high energy laser weapons[1]. In daily life and industrial production, high pulse repetition frequency switches can greatly improve work efficiency in sewage treatment, food processing and other fields[2-3]. The existing pulse power technology switches include solid switches, thyratron switches, field distortion switches, pseudospark switches and so on. However, only the pseudospark switch can combine high power and high PRF performance. In the Z-pinch nuclear fusion device, the pseudospark switch is the only switch with PRF operation capability[4]. Therefore, the pseudospark switch with high repetition frequency is one of the leading directions of the development of high power pulse field in the world.
Double-pulse triggering structure: V.D. Bochkov et al. [5-6] of the Russian Institute of High Current Electronics developed a series of commercial high repetition frequency pseudospark switches (TPI type). All of them adopt the structure of glow discharge and double-pulse triggering, and the PRF reaches 20kHz.
Based on the electrode structure of glow discharge and double-pulse trigger [7], we designed the high PRF pseudospark as shown in Figure 1(a), which is composed of hollow anode, grid, hollow cathode and glow trigger structure, and the trigger structure includes auxiliary glow discharge anode, auxiliary emission electrode and Faraday cup, its photo shown in Figure 1(b). Dual pulse triggering is divided into main-trigger voltage Utcp1 and pre-trigger voltage Utcp2. The Utcp2 is applied to the auxiliary glow discharge anode, and the Utcp1 is to the grid. The electronic path is shown in the arrow in Figure 1(a). In order to verify the effectiveness of double-pulse triggering and the influence of pre-trigger and main trigger pulses on the discharge process, this paper tests the pulse repetition frequency performance of the structure under different gas pressure and trigger voltage, and simulates the trigger unit to observe the influence of different trigger voltages on the cathode current.