Double-sided relativistic magnetron

Abstract

A new scheme of a symmetrically powered relativistic magnetron and several methods of localized electron flow forming in an interaction region are proposed to increase the efficiency of relativistic magnetrons (RM).As was reported for many experiments, the efficiency of RM is about 10 -30% and considerably lower than that of ≥ 70% for the classic magnetrons. A very important reason is the effect of nonsymmetric feeding of power from one side of a magnetron, which is typical for experiments. One-sided powering leads to the axial drift of electrons, to the transformation of transverse velocities of electrons to a longitudinal one and to the generation of a parasitic electron beam which does not take part in energy exchange between electrons and waves at all.A special driver was designed for double-sided powering of RM. The proposed system is compact, rigid and capable of reliable operation at high repetition rates, which is advantageous for many applications.Several smooth-bore magnetrons were tested by means of computer simulations using PIC code KARAT. The results showed a difference between the dynamics of electron flow for one-and two-sided power feeding of the structure under test. It was shown that all electrons emitted from the cathode are captured inside the interaction region under the condition of proper choice of the electrostatic and/or external magnetic field distributions. This situation is practically impossible for a one-sided magnetron.Design of a driver and computer simulation results are presented.