An electrodeless spark discharge acoustic pulse transducer for borehold operations provides an insulating ceramic barrier which contains a small cross-section aperture separating two bodies of electrolyte through which the two zones of liquid make contact. The specific shape and geometry of the insulating barrier being exponentially shaped provides a means for controlling the waveform and frequency spectrum of the acoustic pulse. The transducer has an elastic outer housing and an elastic inner housing with hydraulic fluid between the inner and outer housings. The pressure of the hydraulic fluid may be increased to expand the outer housing against a borehole prior to a spark discharge. The transducer is also provided with a system for venting gas produced as a result of the spark discharge.
Thomas E. Owen;Edgar C. Schroeder