Improved cathode design for long-pulse MILO operation

An improved cathode design for a magnetically insulated transmission line oscillator (MILO) has resulted in extending the radiated microwave pulse duration from 200 ns to over 400 ns. This was accomplished by maximizing the emission uniformity in the launch-point region of the cathode which, in turn, minimized anode plasma formation. The extended RF pulse duration has allowed us to find evidence of a new pulse-shortening mechanism late in the beam pulse: anode plasma formation in the load region.