Gyrotron experiments employing a field emission array cathode

Abstract

The design and operation of a field emission array (FEA) cathode and the subsequent demonstration of the first FEA gyrotron are presented. Up to 10 mA from 30 000 tips was achieved reproducibly from each of ten chips in a gyrotron environment, namely, a vacuum 1 3 10 28 mbar, 250 kV potential with multiple chip operation. The design parameters of the FEA gun were similar to those of a magnetron injection gun with an achievable electron beam current of 50 -100 mA and measured power 720 W cw. Coherent microwave radiation was detected in both TE 02 at 30.1 GHz and TE 03 at 43.6 GHz, with a starting current of 1 mA. [S0031-9007(96)

Simulation of a Crossed-Field Amplifier Using a Modulated Distributed Cathode

“…Examples of these are Magnetrons [1][2][3][4][11][12][13] and Crossed-Field amplifiers (CFAs) [1][2][3][4][13][14][15][16][17][18][19]. Fast-wave devices use the cyclotron frequency for operation; a gyrotron [1][2][3][4]20] is one example of many gyro devices.…”

“…The use of FEAs in MVEDs has been proposed and implemented for microtriodes [5,96,97], klystrodes [6,32,96,97], twystrodes [96], gyrotrons [20], magnetrons [12,28,29,98], and TWTs [8,9,99,100]. The use of GFEAs in gated emission devices such as the microtriode, klystrode, and twystrode is very appealing due to the low transconductance (the ratio of the change in current at the output terminal to the change in the voltage at the input terminal of an active device), short transit times (the time for an electron to travel from the emitter to the gate), and the small package.…”

“…20 shows the energy level diagram at the surface of a material with and without an applied electric field.…”

“…20: A simple example of the divergence free region current propagation from the injection point to the domain edge at (a) t = t 0 , (b) t = t 1 , (c) t = t 2 . Red dots indicate cells where the divergence is not equal to zero, and green dots are divergence free points.…”