Improvement of the reproducibility in electrohydraulic generators by using conducting liquid (medical US lithotripsy)

In an electrohydraulic generator, two underwater metal electrodes are connected in series with a capacitor charged to a high voltage. When the circuit is switched on, a plasma occurs reaching temperatures of thousands of degrees Celsius and resulting in a compressive pressure pulse. The formation of the plasma is a particular nonreproducible phenomenon inducing great variations in the pressure pulse values. Measurements obtained by triangulation show that the origin of the plasma changes and that the center of the spherical divergent shock wave can be located largely outside the interelectrode gap when tap water is used. However, the center of the shock wave is always located at the same place when electrolyte is used. The plasma duration was also photographed to better study the nonreproducibility of the shock-wave amplitudes.<
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