Gas-discharge Plasma Electrode Electro-optical Switch And Switching Characteristics

High-power laser driver system for ICF has complicate configuration, requires large aperture optical devices which allow high power laser passing them. In order to resolve laser control and reverse lasers isolate in driver system we need an optical switch with large aperture, well uniformity everywhere in the aperture, rapid switching speed and high threshold of damnification. The plasma electrode pockels cell (PEPC) electro-optical switching can satisfy the requirements. The gas discharge in the PEPC electro-optical switching is a complicated microcosmic process, and some microscopic quantities are difficult to be measured, so it is impossible to directly research the microcosmic processes. By modeling for discharge processes in the PEPC electro-optical switching of one-dimension, we can get various microscopic quantities in the discharge process, by which we can deeply research the relationship between the microcosmic physical processes of gas discharge plasmas and the macrocosmic parameters of PEPC electro-optical switching. Therefore, the research is very useful for designing and optimizing the electro-optic switches.In the dissertation, according to operating characteristics of plasma electrode PEPC electro-optical switching driven by one-pulse-process and the principle of gas discharge, we improve the model of one-dimension discharge for helium discharge that includes calculating the effective length of discharge for one-dimension model of PEPC, introducing effective electric field in drift velocity calculation for positive ion. By simulating the PEPCs with helium or argon, and with KDP crystal or DKDP crystal respectively, we obtained curves of time evolution for voltage on electrodes, discharge current, switching efficiency as well as the space distributions of particles. At last, the influence of argon pressure on the PEPC working characteristics is analyzed.The calculating results indicate that the main particle species affecting the discharge processes are electron, atomic ion and excited atom, the model with 3 particles can deduce calculating time in the case of keeping calculating accuracy; under the same conditions argon discharge in PEPC breaks down faster than helium, but switching rising time in argon is longer than in helium, and switching efficiency in argon is lower than in helium; in the case of high argon pressure, charged particles density is high, electron temperature is low and charging voltage on the crystal is high. Comparing with experiment data, we find the simulating results are coincident with experiments.