Phase-control of a rising sun magnetron using a modulated, addressable, current source

Abstract

It has been proposed that the use of gated field emitters with a faceted cathode in place of the conventional thermionic cathode could be used to control the current injection in a magnetron, both temporally and spatially. In this work, this concept is studied using the particle-in-cell code VORPAL. The magnetron studied is a ten-cavity, rising sun magnetron, which can be modeled easily using a 2D simulation. The magnetron has a ten-sided faceted cathode. The electrons are injected from three emitter elements on each of the ten facets. Each emitter is turned ON and OFF in sequence at the oscillating frequency with five emitter elements ON at once to obtain the five electron spokes of the π-mode. The simulation results show that the modulated, addressable cathode reduces startup time from 100 to 35 ns, increases the power density, controls the RF phase, and allows active phase control during oscillation.