Recent Advances on the Magnetron with Diffraction Output

Abstract

The relativistic magnetron with diffraction output (MDO) was predicted in particle-in-cell (PIC) simulations to achieve 70% electron beam-to-microwave power conversion efficiency. In experiments at the University of New Mexico (UNM) a conversion efficiency of >60% was measured in experiment until the cathode endcap flashed over, after which the efficiency dropped to below 40% [1]. Since these experiments the UNM group predicted similar efficiencies for an MDO powered using a virtual cathode [2]. The proposed advantage of operating the MDO with a virtual cathode as opposed to a physical cathode was the elimination of pulse shortening via AK gap closure. Finally, more recent work suggests that the use of a magnetic mirror to suppress axial leakage current can lead to maximal efficiency of an MDO driven by a virtual cathode [3]–[5]. This presentation will provide the latest experimental results on these subjects.