Intense beam fundamental mode large-orbit gyrotron studies

Experimental and theoretical studies of a fundamental mode large‐orbit gyrotron designed to produce high‐power rf radiation in the TE11 mode at about 1 GHz are reported. Theoretical calculations performed as part of the experimental design process are presented. Results of initial experiments are reported in which 500–1000 MW of rf radiation was observed at frequencies 700 and 1200 MHz, consistent with theoretical expectations. The estimated eletronic efficiency of the device is about 10%. Gas cell breakdown patterns produced by the rf pulse are consistent with operation in the desired TE11 mode.