Investigation of the plasma edge cathode

A plasma cathode for high current density electron extraction is investigated. The electrons are extracted transversely to the flow of a plasma jet for several microseconds without significant gap closure. The maximum extractable current density is given by the density and the electron temperature of the plasma jet. The composition of the plasma jet is analyzed by a time-of-flight method. The geometry of the electron beam is investigated by a multiple pin hole imaging method. This yields the intrinsic divergence of the electron beam and the shape of the effective plasma boundary.