Acoustically Enhanced Multichannel Spark Gap Switch
AIR FORCE WEAPONS LAB KIRTLAND AFB NM
Pagination or Media Count:
The inductance of a gas switch is reduced by causing it to operate in a multichannel mode. The reduced inductance is desirable to increase the switching speed. Normally, multichannel operation is achieved by careful alignment of the electrodes, use of special gas mixtures and by application of a trigger which is faster than the arc channel formation time. 1 Under normal circumstances multichannel formation is of a somewhat random and unpredictable nature. By establishing an acoustic standing wave along the electrodes the molecular number density is modulated at a precise number of positions corresponding to the nodes of the standing wave. By synchronizing the trigger with the density modulation very predictable multichannel performance and other advantages are obtained. The electrical breakdown of the gas is determined primarily by the ratio of the electric field E to the molecular number density N, i.e. EN. In conventional gaps the sites where the emission initiates on the cathodes surface has small irregularities, resulting in local E field enhancement. The gas pressure is static so N is the same everywhere. The resulting local EN enhancements induce the initiations at theses sites. The discharge erodes the cathode surface and thus the number and location of these enhanced sites are random. An experimental rail gap was constructed with acoustic drivers at each end. the drivers were powered with a dual channel audio amplifier rated at 200 watts per channel up to 20kHz.
- Electrical and Electronic Equipment
- Combustion and Ignition