Microwave emission from pulsed, relativistic e-beam diodes. II. The multiresonator magnetron

Abstract

The design and operating characteristics of relativistic, electron beam magnetrons are described. The magnetrons are comprised of a pulsed field-emission cathode (-360kV, ~15kA, -30nsec) and several coupled resonators embedded in the anode block. The tubes are designed to work at fixed frequency, in range from 2.3 to 5GHz. The peak powers generated are typically 500 to 1000MW.

Numerical simulation of oscillating magnetrons

“…These impressive results have reawakened an interest to better understand the interaction of the electromagnetic field and the dense space charge cloud in magnetron-type devices. Numerous attempts have been made over a span of forty years,"- 1 4 to calculate self-consistently the rf fields under the large signal conditions prevalent in the magnetron, and from these to predict the current, voltage, microwave power and efficiency.…”

Numerical study of relativistic magnetrons

“…The A6 magnetron configuration [5], which demonstrated in the late 1970s microwave emission at unprecedented high power levels, has become the prototype for relativistic Three remarks are in order concerning the simulation results shown in Fig. 3.…”

“…Note that only for an ideal power supply Bekefi [5] that magnetrons with a large anode-cathode gap (small-aspect-ratio) favor 7r-mode operation. Because the electric field excitation for the 27r-mode is mostly azimuthal near the cathode, it is plausible to argue that the 27r-mode does not interact strongly with the electrons, thereby resulting in a relatively weak azimuthal bunching and energy transfer from the electrons to the rf field.…”

“…Power levels from tens of watts to hundreds of kilowatts can be achieved in the decimeter and centimeter wavelength range with conversion efficiencies as high as 80%. While research on conventional magnetrons has a long history, the resurgence of interest in magnetrons has been triggered, in large part, by the pioneering work of Bekefi, Orzechowski, and Palevsky [3]- [5].…”

“…Since the classic experiments on the so-called A6 magnetron [5], which produced an unprecedented rf output power of 900 MW, the A6 magnetron configuration has become the prototype for the next generation of relativistic magnetrons [6]- [10]. In a relativistic magnetron, a field-emission diode is pulsed in the several hundred kilovolt to megavolt range in order to generate microwaves at gigawatt power levels.…”