A high-efficiency repetitively pulsed magnetically insulated transmission line oscillator

• A high-efficiency repetitively pulsed magnetically insulated transmission line oscillator (HERP- MILO).
• Three improvements: a focusing electrode, an array of round holes and an auxiliary vacuum cell.
• The simulation and experimental results confirm the above design ideas.

A high-efficiency repetitively pulsed magnetically insulated transmission line oscillator (HERP-MILO) is presented in this paper. In the HERP-MILO device, there are three improvements. Firstly, a focusing electrode is introduced to enhance the power efficiency. Secondly, an array of round holes is added to the outer circumference of slow wave structure (SWS), which can enhance the flow conductance in the beam-wave interaction area through the way of exhausting radially. Thirdly, an auxiliary vacuum cell is introduced round the SWS, and there are 6 vacuum pump ports in the auxiliary vacuum cell. The auxiliary vacuum cell helps to inhibit the excessive pressure growth in the beam-wave interaction area during the HERP-MILO operation, and the 6 vacuum pump ports can enhance the vacuum pumping speed and efficiently reduce the vacuum recovery time. The simulation and experimental results show that the focusing electrode is effective to enhance the power efficiency. Moreover, the experimental results also show that the array of round holes and the auxiliary vacuum cell can improve the vacuum condition of the HERP-MILO, which is favorable for the increase of the duty cycle, the pulse repetition rate and the cathode lifetime of the HERP-MILO.