Barnetron microwave amplifiers and oscillators

Abstract

A cyclotron maser microwave amplifier and oscillator which utilizes non-relativistic electrons in cyclotron motion and a spatially nonlinear electrostatic field which is produced by the space charge of the electrons. The term 'spatially nonlinear electrostatic field' encompasses static electric fields whose magnitude can be described mathematically as varying in a nonlinear manner as a function of position in one or more directions. As taught by U.S. Pat. No. 4,253,068 of Feb. 24, 1981, 'Cyclotron Maser Using a Spatially Nonlinear Electrostatic Field', completely non-relativistic electrons may be used in principle for which phase bunching will occur due to the nonlinear motions induced by the electrostatic field, resulting in stimulated emission of cyclotron radiation for use in a microwave amplifier or oscillator. U.S. Pat. No. 4,253,068 teaches that appropriate nonlinear electrostatic fields can be established by suitably shaped electrodes and a low charge density electron beam. The present application teaches that appropriate nonlinear electrostatic fields can be produced by the self fields of the space charge of the electron beam. Resulting amplifiers and oscillators are here named barnetron amplifiers and oscillators. An electron gun which produces an annular electron beam with components of velocity perpendicular and parallel to an axial magnetic field.