Development Of Rotary Arc Gap-Switch In Axial Magnetic Field

Pulsed power technology has been used extensively in the fields of scientific experiments, national defense, biomedicine and environmental protection etc. As one of the crucial components, a high-energy switch with high voltage, high current, large charge-transfers, slight electrodes erosions, long life-time and highly reliability is greatly expected to meet the rapid development of pulsed power system, especially the main amplifier power conditioning for the laser fusion. In this thesis the rotary arc gap-switch in axial magnetic field is fully explored.This thesis initiates with the review of different types of high power pulse closing switches including the operating principles, characteristics and parameters. Especially the recent development of the high coulomb and current closing switch in various countries including the requirements of several power conditioning systems, kinds of switches, operating principles, recent specifications, advantages and disadvantages are introduced here.A Rotary Arc Gap-switch in axial magnetic field is developed and its operating principle, the move mechanism of the arc in axial magnetic field and the erosion mechanism of the electrodes are introduced. The performance of the switch can be improved by: (1) select some material which is difficult to be melted and eroded to be the electrodes material; (2) coils to bring axial magnetic field are appended to the switch to make the arc move continuously along the electrodes which result in the arc heat and erosion are dispersed to a large area; (3) coaxial columns configuration makes the inter-action area of the arc and electrodes increased and the current density is greatly reduced; (4) optimize the electrodes configuration to make the electric field as uniform as possible, as a result, the discharge dispersibility is great and the electrodes erosion is reduced.A Rotary Arc Gap-switch of coaxial columns configuration employing a trigger electrode and coils to bring axial magnetic field is developed, what's more, the arc is stable in the arc-steady-area by the average current along the inner electrode and the mirror-magnetic field design. The optimization of electrodes configuration promises the electric field of the switch gap as uniform as possible. The dimensions of the coils and the distance between the upper coils and the nether coils are confirmed after many calculations and emulations. The maximal electromagnetic force of the coils and the theoretic rotary velocity of the arc are presented.On the bases of several triggering modes and circuits, three candidate trigger system are designed. They are pulsed transformer trigger system, current extended in addition to pulsed transformer trigger system and Marx generator trigger system. The trigger discharge experiments with the three trigger systems cooperating with switches of two configurations have been undertaken. The Marx generator trigger system and RAG switch without trigger electrode are chosen to be the final scheme of this thesis.The elementary experiments indicate that the self-breakdown voltage of the switch is a little dispersive because of machining, the average self-breakdown voltage is about 30kV, and the switch can withstand 25kV voltage. The high current circuit has been designed and the current waveform has been simulated. Seven times of high current experiments of the switch indicate that the arc is authentically rotating and there are slight erosions on the electrodes. The switch has been demonstrated to discharge a 15kV with peak currents of 200kA , pulse width of 420~470us and charge transfers of 50C /shot. In a word, the switch can meet the former requirement of Shenguang III.Discharging a 23kV with peak currents of 300kA , pulse width of 500us and charge transfers of 100C /shot, highly reliability and long lifetime etc, the trigger pulse sharpener and magnetic switches isolated system are going to be developed in the future.