20 research outputs found
Observation of Dynamic Interactions between Fundamental and Second-Harmonic Modes in a High-Power Sub-Terahertz Gyrotron Operating in Regimes of Soft and Hard Self-Excitation
Dynamic mode interaction between fundamental and second-harmonic modes has been observed in
high-power sub-terahertz gyrotrons [T. Notake et al., Phys. Rev. Lett. 103, 225002 (2009); T. Saito et al.
Phys. Plasmas 19, 063106 (2012)]. Interaction takes place between a parasitic fundamental or firstharmonic
(FH) mode and an operating second-harmonic (SH) mode, as well as among SH modes. In
particular, nonlinear excitation of the parasitic FH mode in the hard self-excitation regime with assistance
of a SH mode in the soft self-excitation regime was clearly observed. Moreover, both cases of stable twomode
oscillation and oscillation of the FH mode only were observed. These observations and theoretical
analyses of the dynamic behavior of the mode interaction verify the nonlinear hard self-excitation of the
FH mode