M. E. Read

A self-consistent field theory for gyrotron oscillators: application to a low Q gyromonotron

This paper presents an application of a self-consistent field theory for gyrotron oscillators to a low Q TE01 mode gyromonotron. In this model, the RF field profile function satisfies a wave equation in which the AC beam current appears as a source. The wave equation is solved simultaneously with the electron equations of motion. The results of calculations are compared with experimental data for the efficiency, starting current, and operating frequency. To facilitate a detailed comparison between theory and experiment, data have been taken over a wide range of beam currents and axial magnetic fields. The gyromonotron studied in this work has a tapered cavity structure to enhance efficiency, and a low Q factor to enhance output power. A strong self-consistent field effect is observed in the behaviour of the starting current.

Use of weakly irregular waveguide theory to calculate eigenfrequencies, Q values, and RF field functions for gyrotron oscillators

The design of open resonators for gyrotron oscillators requires knowledge of the reso nator cigenfrequencies, Q values, and resonant RF field functions. These quantities can be obtained for open cavities with weakly irregular profile using the theoretical approach of Vlasov et al. which is based on the one-dimensional wava equation where / is the longitudinal variation of a TE or TM modo and β is the mode. propagation factor. In this paper we discuss the approximation.implicit in this approach and present a comparison of theoretical results and experimental data

Experimental study of a single-mode quasi-optical gyrotron

Abstract The first experimental results of a high-power quasi-optical gyrotron are presented. The cavity was designed to eliminate all mode competition, longitudinal as well as radial. Powers to 80 kW and efficiencies to 11% were measured with indications that the actual electronic efficiency was at least a factor of 1·5 greater.

Self-Consistent Field Model for the Complex Cavity Gyrotron.

Mode competition in gyrotrons with highly overmoded cavities can degrade efficiency and output mode purity. One approach to mode selection which has been demonstrated experimentally involves a sudden change in the cavity radius. Cavities with this feature are called ‘complex-’ or ‘step-cavities’. This paper presents a theoretical model for the step-cavity gyrotron. The model applies to the steady state operation. The axial variation of the cavity rf fields is determined self-consistently with the electron beam motion by integration of the wave equation simultaneously with the nonlinear electron equations of motion. The model accounts for mode conversion effects at the step as well as beam loading effects such as cavity Q modification and frequency pulling. The model is applied to the analysis of a TE01/TE04 complex cavity gyrotron

Boundary integral method for computing eigenfunctions in slotted gyrotron cavities of arbitrary cross-sections

A boundary integral Greens function technique is devised to calculate eigenfunctions and eigenvalues of open resonators in two dimensions. These eigenfunctions damp exponentially in time, but diverge in space. The cavity Qs of a variety of open resonators are calculated and compared with experimental cold tests.

Power limits in cylindrical gyromonotrons using TEon1 modes

Upper and lower limits to the output power of highly efficient gyrotron oscillators operating with TEon1 modes, due to lower and upper limits on the cavity Q, are given.

Sub-nanosecond pulselength millimetre wave generation with a phase modulated quasi-optical gyrotron

It is shown that a quasi-optical gyrotron operating with a current modulated second beam can produce a train of phase-locked millimetre wave pulses.