Numerical study of a high-harmonic gyrotron using an axis-encircling electron beam

A high-harmonic gyrotron using an axis-encircling electron beam has been designed and studied. The eighth harmonic oscillation at 0.42 THz can be realized in the designed gyrotron, leading to a significant reduction of the required external magnetic field strength. The operation of the gyrotron is characterized using 3-D particle-in-cell simulations.