A nonlinear self-consistent simulation code is employed to investigate the behavior of the outer-slotted-coaxial waveguide gyrotron traveling-wave amplifier (gyro-TWA). The influences of the velocity pitch, frequency, and input power of the electron beam on efficiency, output power, and saturated gain are simulated and discussed in detail. It is predicted that this design with 95 GHz, TE/sub 3,1/ will yield a peak output power of 264.3 KW, a peak efficiency of 33.7%, and saturated gain of 44.2 dB.

Self-consistent nonlinear investigation of an outer-slotted-coaxial waveguide gyroton traveling-wave amplifier

In this paper, the design and stability analysis of a W-band second-harmonic Gyrotron Travelling Wave Tube (gyro-TWT) amplifier loaded with the wedge-shaped lossy ceramic rods, operating in the circular azimuthally symmetric TE02 mode, has been presented. The stability of the gyro-TWT has been investigated against the spurious oscillations, including the reflective oscillation, gyrotron backward oscillation (gyro-BWO), and absolute instability. The transmission loss for the operating mode has been calculated as $\sim 19$ dB/cm at 91.4 GHz for achieving the stability. Furthermore, the gyro-TWT using the distributed loaded RF section has been investigated for its nonlinear behavior using a self-consistent nonlinear analysis. The saturated RF output power of $\sim 450$ kW at 91.4 GHz with $\sim 18$ % efficiency, $\sim 30$ -dB saturated gain, and 3-dB bandwidth of $\sim 3$ % has been achieved for an electron beam of 100 kV and 25 A.

Design and Stability Studies of Second-Harmonic Gyro-TWT Amplifier Using Wedge-Shaped Lossy Ceramic Rod-Loaded Mode Selective RF Interaction Circuit

The behavior of a two-stage slotted Gyro-TWT amplifier is evaluated with a self-consistent nonlinear slow-timescale simulation code. The effects of the sever position and the lengths of the first section, sever, and the second section on beam-wave interaction are discussed in this paper. And the influences of the magnetic field and the electron beam's velocity spread on efficiency, gain and bandwidth are also simulated and discussed in detail. The electron beam we employ encircles around the axis of the wave guide.

Sheng Yu

Papers

Self-Consistent Nonlinear Simulation of a Severed Slotted Gyro-TWT