Patent ID: 8105325

Claim:
A plasma surgical device comprising: an anode, positioned at an outermost distal end of the device, a cathode; an electrical insulator sleeve surrounding a substantial portion of the cathode, wherein there is a gap formed by an inside surface of the insulator sleeve and an outside surface of the cathode, the gap being capable of passing a plasma-generating gas; and one or more intermediate electrodes electrically insulated from each other and from the anode, one or more of the intermediate electrodes forming a plasma channel having an inlet at a location between the cathode and the anode, the plasma channel extending longitudinally through a hole in the anode and having an outlet opening at a distal end of the anode, the plasma channel having a throttling portion, the throttling portion dividing the plasma channel into (1) a high pressure chamber positioned upstream of the throttling portion formed by two or more intermediate electrodes and having a first maximum transverse cross-sectional area, and (2) a low pressure chamber positioned downstream of the throttling portion and having a second maximum transverse cross-sectional area, the throttling portion having a third transverse cross-sectional area, which is smaller than the first maximum transverse cross-sectional area and the second maximum transverse cross-sectional area.