An electrosurgical working end that utilizes supercavitation phenomenon for controlled application of electrosurgical energy to tissue. In one preferred method of the invention, the system utilizes an electrosurgical surface that is rotatable in a liquid substance at very high surface velocities capable of localized lowering of the pressure of the substance below its saturated vapor pressure to cause supercavitation, and contemporaneously applying electrical energy from the electrosurgical surface across the cavity to ablate adjacent tissue. The system creates supercavitation with surface velocities of greater than about 70 m/sec in a liquid substance by means of high speed rotation and optionally ultrasound actuation.
