RF behavior of a 35 GHz conventional cavity gyrotron using multimode analysis and PIC simulation

ABSTRACT

In this paper, the RF behavior of a 35 GHz, TE₀₄ mode cylindrical cavity gyrotron is investigated using the nonlinear multimode theory and PIC code “CST Particle Studio”. A code is developed to realize the beam-wave interaction mechanism using time-dependent multimode theory. The cold cavity behavior is observed for the cavity operation in the designed TE₀₄ mode and 35 GHz frequency. The magnetic field profile is kept uniform along the length of the interaction structure. The output power is estimated for the designed mode as well as all nearby competing modes using the multimode analysis and PIC simulation. This yields the output power more than 200 kW with 33% efficiency in the designed TE₀₄ mode, whereas the smaller output power in the nearby competing modes. Power sustainability is also observed for the stable operation of the device. The effects of beam velocity spread and detuning of magnetic field on its performance are also observed.

KEYWORDS:

• Gyrotron
• beam-wave interaction
• multimode analysis
• particle-in-cell

Acknowledgements

One of the authors (Ashutosh) is thankful to the Center of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology (BHU), Varanasi and the Department of Electronics Engineering, National Institute of Technology, Patna for providing their valuable support.

Disclosure statement

No potential conflict of interest was reported by the author(s).