Initial Experimental Results for a High Power Frequency-Tunable sub-THz Gyrotron

Experimental results of a high power frequency-tunable sub- THz gyrotron is presented in this paper. A series of high-order axial modes in a long gyrotron cavity are excited successfully by an electron beam of high voltage and high current. Initial experimental results show that a frequency tuning range of 0.79 GHz from 218.27 GHz to 219.06 GHz is obtained by only tuning the operating magnetic field. And during the frequency tuning, the output power is no less than 0.5 kW, while the maximum output power is 3.80 kW. The axial mode transition in high power gyrotron is experimental demonstrated. This results should be conductive to the future development of frequency-tunable gyrotron for some up-and-coming THz applications.