Theoretical and Experimental Investigation on the Effect of Beam Misalignment on a Second Harmonic 0.8 THz Gyrotron

The misalignment is an important factor that accounts for the deviation of the experimental results from the theoretical design of high-frequency gyrotrons. This article investigates the effect of the electron beam misalignment on the operation of a second harmonic 0.8 THz gyrotron through theoretical analysis and experiments. The rise of the starting current, efficiency degradation, continuous frequency tunability, and harmonic mode competition of the 0.8 THz gyrotron under the effect of different types of beam misalignment is analyzed comprehensively using a self-consistent model, providing a general picture for the potential effect of beam misalignment on high-frequency harmonic gyrotrons. The alignment process and experimental results of the 0.8 THz gyrotron tube installed in a 15 T magnet with
XY
-tables and optical probes are also discussed. The results are referential to the development of high-frequency gyrotrons for high-power THz applications.