An Electron Population Analysis Technique for Understanding Fundamental Cross-Field Electron Device Physics

An electron population analysis technique will be presented. The technique enables deep insights into results generated from Particle-In-Cell (PIC) simulations by constructing the normalized probability distribution of the positions and velocities of the electron population in separate axes and plotting them against time. The technique also analyzes the electron population to extract the net electron movement in each axis. This technique was originally developed during the simulation study of the L3Harris CWM-75kW industrial magnetron to analyze the relationships between behaviors of the electron population and magnetron oscillation startup. The simulation results of the CWM-75kW using the PIC code VSim has been published along with some preliminary application of this electron population analysis technique. 1 Recent work focuses the application of the electron population analysis technique to the 2D Rising Sun Magnetron that was simulated previously. 2 The magnetron was studied under three conditions: 1) no priming, 2) RF priming, and 3) cathode modulation. The 2D model requires less computational resource and allows more cases to be simulated. Recent electron population analysis results suggest there exist strong correlations between increased level of electron cycloidal motion and magnetron start up. The technique has applications far beyond analyzing magnetron simulation results; it can be used to analyze simulation results of other electron devices such as cross-field amplifiers, traveling wave tubes, etc. Ongoing research also uses the technique to study Brillouin flow and diocotron instability during magnetron startup.