Closing performances of double-gap laser-triggered vacuum switch

To develop high-voltage-pulsed power switches with better performances,a multi-gap laser-triggered vacuum switch is proposed in this study.Based on established test pro-totype for double-gap laser-triggered vacuum switch,closing processes of double-gap laser-triggered vacuum switch are discussed combined with laser-produced plasma.Closing performances of double-gap laser-triggered vacuum switch under different gap polarity configurations,operating voltages,laser energies and laser split ratios are inves-tigated.Closing time delay characteristics of double-gap laser-triggered vacuum switch and single-gap laser-triggered vacuum switch are compared later.The test results prove that,affected by the imbalanced developed initial plasma between gaps,double-gap laser-triggered vacuum switch with two positive gaps and 1:1 laser split ratio presents best closing performances than other switches.With the rise of laser energy,closing delay time and jitter time of double-gap laser-triggered vacuum switch both decrease,while the influences from increasing voltages are weak.Closing delay time of P-P type double-gap laser-triggered vacuum switch can be controlled within 103�1.5 ns under 90 mJ laser energy,and it is about 10 ns longer than single-gap laser-triggered vacuum switch.For some direct current applications with changing voltage directions,P-N type double-gap laser-triggered vacuum switch with 1:1 laser split ratio shows more stable closing per-formances.In addition,closing performances of double-gap laser-triggered vacuum switch can be further improved by optimizing the developments of initial plasma in series gaps.