An Experimental Investigation of a 0.8 THz Double-Beam Gyrotron

Abstract

In this paper, we present and discuss the new experimental results that characterize the output parameters, and the overall performance of the recently developed 0.8 THz double-beam gyrotron operating at the second harmonic of the cyclotron frequency on the TE8,5 mode. Alongside with this design mode, several other resonances excited at both the fundamental and second harmonic operations in a wide frequency range have been studied. These experiments demonstrate that the usage of a double-beam electron-optical system opens more possibilities for realization of such regimes of operation that otherwise are not accessible in a conventional (single-beam) gyrotron due to a severe competition between the neighboring modes and the narrowness of the zones of a stable single mode operation. Most notably, the results prove that second harmonic operation at higher beam currents and respectively at higher levels of the output power are possible as expected from the preceding theoretical considerations and numerical studies. The results of this study are helpful for getting a better insight in the physics of the operation of the double-beam gyrotrons and suggest some possibilities for further optimization of both the design of the tube and the experimental setup.