Space charge distribution in magnetrons

Some models of the space charge in magnetrons are reviewed. PIC simulations are taken on X band magnetrons to compare with the theory analysis. The Brilliouns theory is effective in getting the height and density of the hub, but it is difficult to explain charge density at the edge of the hub for the Brillouins theory uses single-particle motion theory. There is discrepancy in spoke density with all these theories. The difference of the charge density at the edge of the hub is assumed to be the reason for the discrepancy. Approaches to maintain spoke density in magnetrons are proposed according to the guiding center fluid theory in S.Riyopoulos work.