Electrosurgical devices and methods

A bipolar electrosurgical device, comprising:

• a handle;
• an elongated shaft coupled to the handle, the elongated shaft comprising an outer sleeve having a bore;
• a dielectric member axially moveable in the bore, wherein the dielectric member comprises an annular recess that exposes an inner surface of the outer sleeve;
• a bipolar electrode arrangement carried by a distal portion of the elongated shaft comprising an active electrode and a return electrode that are electrically insulated from one another, wherein a surface area of the active electrode and a surface area of the return electrode change upon axial movement of the dielectric member, wherein the return electrode is located at the inner surface of the outer sleeve;
• and
• a reciprocating mechanism configured to reciprocate the active electrode over a selected stroke at a selected rate to optimize plasma formation.