Phase I Design of a Surface Discharge Low Frequency Acoustic Source

Pulsed power technology, which calls upon the rapid discharge of capacitively stored electrical energy, can replace explosives in many applications. Mining metal forming, and echo ranging are examples. This proposal is for the design of a pulsed power sonobuoy suitable for use in a three-element array, to provide, the acoustic output effectively equivalent to that from a 4-pound sound underwater source (SUS) charge. A preliminary design is presented which takes into account the major sub-systems for an A-sized sonobuoy. The acoustic source is an underwater spark discharge which propagates along the surface of a ceramic insulator. The spark is driven by a low inductance pulsar consisting of a capacitor and a gas-pressurized spark-gap. While the capacitor is being charged the spark-gap insulates the capacitor from the ceramic insulator. A rapid movement of a relay contact triggers the spark-gap and initiates the surface discharge along the ceramic insulator. A compact switching-type power supply charges the capacitor in less than 10 s. A 48 V battery storing 1000 Watt-hours (3.5 MJ) provides power to the sonobuoy. A compact control unit equipped with a fiber-optic input permits communication between the submerged sonobuoys and a surface control unit.