A high-current-density nonclosing plasma cathode

A novel plasma cathode has been demonstrated. Its operation depends on the presence of a magnetic field and requires a low-pressure burst of gas to form a crossed-field discharge. The electron current that can be extracted is controlled by the discharge current. When the extracted current is less than the space-charge limit there is no diode closure. The fundamental characteristics of intense crossed-field discharges are measured, and cathode tests up to 6 A cm−2 at 100 kV are reported, in a 100-cm2 cathode with 5-μs pulses.