Simulations Of A Miniaturized And Repetitive Plasma Opening Switch

Inductive energy storage pulsed power systems have undergone much development because of their advantages of high energy storage density,low cost and simple structure.The key component of inductive energy storage system is the opening switch,which is usually suitable for single operation only,limiting their wider applications.Plasma opening switches(POS)can operate repetitively in principle,and they have been applied to some large inductive energy storage systems,due to their high peak current,low loss,high withstand voltage,low volume etc.The research to miniaturize the POS has important significance for the development of compact,repetitive pulsed power systems.In this paper,the simulations of a POS with low driving current are carried out.The main work is as follows.1.To establish a numerical model,the conducting and opening models of POS are discussed,including bipolar conduction model,magnetic pressure model and snowplough model for the conducting phase,as well as erosion model,magnetic pressure model and snowplough model for the opening phase.The relationship between the physical parameters of POS in the conducting phase are deduced.In the process of switch opening,the expansion of the sheath is influenced by the radial motion of the ions,which is the key factor influencing the switch opening characteristics.2.The Particle-In-Cell(PIC)method for the simulations of POS is described,including the the algorithm of particle moving and the boundary conditions of the electromagnetic field.The method is verified against existing simulation work.For typical inductive energy stroage pulsed power generators used in high power microwave fields,the power is around 10 GW,and the impedance around 10 ?.So a POS of 30 kA driving current is selected as the simulation model.The opening characteristics of such a low current coaxial POS is then studied by a PIC method.Results show that the POS can work normally under the current of 30 kA,proving the feasibility of a miniaturized POS.The physical mechanism during the opening phase of the POS is analyzed in detail from the simulation.To optimize the design of a POS,several parameters(cathode radius,driving current and plasma type)which influence the characteristics of POS are studied.The results show that decreasing of the cathode radius is beneficial to enhance the opening characteristics;reducing the driving current goes against the POS opening due to decrease of azimuthal magnetic field strength on the cathode surface of POS;the injected ion plasma type has a great influence on the characteristics of POS opening,and hydrogen plasma is suggested the best choice.3.A compact inductive energy storage pulsed power system based on low current POS is designed.Based on the equivalent circuit model of the system,the requirements of the charging power supply and the calculation of the power in the system are summarized.Various plasma sources required for POS are investigated,and it is shown that a cable plasma gun with titanium hydride as dielectric medium is the suitable choice for a miniaturized repetitive POS.