Underwater Electrodeless Spark Sound Source

摘要

The research discussed in this report was concerned with: device modifications intended to reduce secondary, device-scattered emissions, exploration of low energy (20-50 joule) discharges, the effects of gas dissolved in the electrolyte, and bubble pulse suppression. The dominant source of device-scattered emissions was an internal reflection. A configurational change greatly reduced this effect. The acoustic output of the low-energy electrodeless spark discharge is a single-polarity pulse of one- to two-microsecond duration which has a peak pressure at one yard of up to 100,000 d sq cm. The low energy discharge is extremely reproducible and capable of operation in electrical parallel with other electrodeless spark sources without detrimental mutual interaction. The use of degassed electrolytes greatly reduces the gas evolved and eliminates the need, in many instances, for forced electrolyte circulation. The bubble-pulse peak pressure can be suppressed with low energy discharge, to at least 20 db below the peak pressure of the primary pulse. Retention of a sufficient remnant voltage following high energy (thousands of joules) discharges is difficult; as a result, effective 'automatic' bubble pulse suppression is relatively difficult with high energy discharges. (Author)