Numerical Simulation Study On Discharge Characteristics Of Low-pressure Gas Under External Particle Source Injection

Switch technology is the most important technology of linear transformer driver(LTD).The lifetime of the switch needs to be at least 107,and it is easy to trigger hundred thousands of swithes synchronously,to keep the LTD operating.In order to meet the needs of the LTD switch,we gave a new model of discharg by referring to the advantages of preionization switch and low-pressure switch,and studied the characteristic by numerical simulation.We established the physical model of the switch by Geant4 and verified the reliability of the model due to two theoretical functions.Using the physical model,we studied the energy of the injected electron,the gas variety,the gas pressure and the electrode radius,which had influence in the outgoing electron gain.Due to the study,we found that the gain of the outgoing electron was maximum when the energy of the injected electron was about IkeV.The ionization coefficient of N2 was much larger than that of He.The gain of the outgoing electron was increasing with increased pressure,and the growth rate was faster than exponential growth.Due to the best operating point of the switch,we analyzed the minimal number of the injected particle which can realize the self-maintained discharge.When the injected particle is electron,referring to the gas discharge theory and others' experiment study,we got the minimal density of the injected electron is 2×105/cm2.While the injected particle was proton,the best injected proton energy is 140keV,and the best gas pressure is 620Pa.To realize the self-maintained discharge,the minimal density of the injected proton is about 1×105/cm2.