介绍了"强光一号"加速器中两种结构的自击穿水开关,建立了简化的开关电路模型,并通过估算和Pspice模拟确定了开关的电路参数,包括电极间杂散电容、火花通道电感和火花电阻.研究表明开关导通过程中的流注电容效应可以忽略,放电通道火花电感与电阻选取流注导通时刻的值,且在主放电电流传递过程中保持不变.根据实验结果,阐述了两种开关击穿的不同特点:对于局部电场增强型的球-板电极结构的主开关,可以采用J. C. Martin稍不均匀场水击穿经验公式估算临界场强;而棒-板电极结构的多针开关,适合用J. C. Martin针-板击穿模型的水击穿经验公式估算临界场强,且并联工作的9个多针开关可以同时形成独立的放电通道.

Two kinds of self-breakdown water switches with different configurations for Qiangguang-I accelerator were described.The electrical model of the water switch was built.By estimation and Pspice calculation,the parameters of the switches were determined.The acquired breakdown characteristics of the two different switches by experiments were described by two different breakdown models.The critical field of the transfer switch could be calculated by J.C.Martin empirical expression about water breakdown with a mostly uniform field.The critical field of the output switch could be calculated by J.C.Martin expression about divergent field of point-plane electrodes.The experimental data of breakdown of water switch show that the above-mentioned methods for breakdown field calculation are reliable.