Nonlinear full-wave-interaction analysis of a gyrotron-traveling-wave-tube amplifier based on a lossy dielectric-lined circuit

Abstract

The stability of the millimeter-wave gyrotron-traveling-wave-tube (gyro-TWT) amplifier can be effectively improved via controlling the propagation characteristics of the operating modes using lossy dielectric-lined (DL) waveguide. Self-consistent nonlinear theory of the electron cyclotron maser (ECM) interaction in lossy DL circuit is developed based on a full-wave study of the propagation characteristics of the DL waveguide. This nonlinear theory fully takes into consideration the waveguide structure and the lossy dielectric characteristics. It is capable of accurately calculating the ECM instability between a cyclotron harmonic and a circular polarized mode, and effectively predicting the nonlinear stability of the DL waveguide-based gyro-TWT. Systematic investigation of a Ka-band TE01 mode DL waveguide-based gyro-TWT is carried out, and numerical calculation reveals a series of interesting results. This work provides a basic theoretical tool for further exploring the application of the lossy DL waveguide in millimeter-wave gyro-TWTs.

Broadband Tunable Pre-Bunched Electron Cyclotron Maser for Terahertz Application

“…The operating parameters are given in Table I. The frequency-domain theory in- , other parameters are as given in Table I. cludes the linear theory [42] and the self-consistent nonlinear theory [43]. Both can efficiently predict the potential steady states of the ECM system in frequency domain [44].…”

“…For each mode, there are two curves with respect to magnetic fields. Each curve is a converged solution predicted by the frequency domain theory [43] indicating a possible path during magnetic tuning process. Here each curve/path is called an instability mode which is with specified accumulative phase difference throughout the interaction circuit [41], [44], [47], [48],…”

High-Efficiency Excitation of a Third-Harmonic Gyrotron

“…The frequency-domain single-mode [35], [36] and the time-domain multimode [20], [21] nonlinear theories are applied to analyze the beam-wave interaction in harmonic gyrotrons. The frequency-domain theory is based on the assumption of the steady single-mode operation.…”

“…Together with the self-consistent electron dynamical equations, the frequency-domain theory is highly efficient to determine the axial field profile of a steady state. The beam-wave interaction equation of the frequency-domain theory is given by [35], [36] …”

Analogy Between Circular Core-Cladding and Impedance Waveguides and Their Membrane Functions

“…Among other applications, dielectric-loaded waveguides have found applications in gyro-devices including gyrotron [2][3][4], gyro-TWT [5][6][7][8][9][10][11][12][13], CARM [14] and others [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. The gyro-devices usually employ RF structures with small structural nonuniformities.…”