High Efficiency Closing Switches for Megamp Pulsed Currents

A closing switch is essentially an insulating gap between two electrodes that is bridged by one or more plasma channels followed, in some cases, by a metal-to-metal contact. The gap may be a vacuum or contain a gas, liquid or solid dielectric. If it exploits the contact plane between two such media, it is known as a surface switch or edge plane gap. The closure mechanism is usually divided into the resistive and inductive phases and the various implementations of the switch technologies exhibit different balances between the two. Some switches are essentially single shot mechanisms, and some do not handle current reversal very well. In developing a high-efficiency, single-turn electromagnetic launcher with current rising to near 1 MA in 1 μs, a number of the above technologies were evaluated in principle, with the most promising being investigated experimentally. Those described also have the potential to handle much higher currents.