Electron-optical system for a high-current Ka-band relativistic gyrotron

Abstract

An electron-optical system for a high-current relativistic Ka-band gyrotron was developed and experimentally tested. The system consists of a coaxial magnetically insulated diode forming a rectilinear hollow beam and an additional short coil (kicker) pumping the transverse electron velocities. An electron beam with a particle energy of 500 keV, a current of 1.5–2 kA, and a pitch-ratio of up to 1 has been produced. The beam is intended for a gyrotron with the output power of 200 MW. The measured beam characteristics are in good agreement with the results of calculations. The influence of the beam and gyrotron cavity axis misalignment on gyrotron operation is analyzed using PIC simulations.

Fully Electromagnetic Code KARAT Applied to the Problem of Aneutronic Proton–Boron Fusion

“…The PiC method for the kinetic description of plasma is implemented in the code. Over the past three decades, numerous problems of non-stationary engineering electrophysics and electrodynamics have been solved with the help of the code KARAT (see [2,3,[39][40][41][42][43][44][45][46][47][48][49][50][51] and references therein). In the present work, the results of a numerical simulation within the framework of the code KARAT of the key physical processes leading to the aneutronic proton-boron fusion were presented in detail and discussed both for laser-driven plasma and for plasma under oscillatory confinement.…”

Development and studies of a high-current relativistic gyrotron with a TM-type operating mode

“…A stainless-steel coaxial edged cathode (1) forms a rectilinear electron beam (2) with a current of up to 2 kA. An electron beam with guiding center radius of 8.5 mm is formed by pumping the rectilinear electron flow in the field of a kicker (3), which is a coil with rectilinear cross-section 3×2 mm 2 and inner radius of 12.5 mm [7]. For optimal matching of the kicker with the source of pulsed voltage, a serial ballast coil ( 7) located inside the main solenoid was used, providing simultaneously the electron beam deposition at the cavity output (6).…”

High-current THz-band gyrotrons based on axial-slit cavities

“…Cavity wall conductivity was taken equal to the copper conductivity. A helical beam with a required radius can be obtained using an electron optics system with a kicker providing electrons transverse velocity in the area of relatively low magnetic field [6]. Similarly to conventional magnetron injector guns, in such a system a section of rising magnetic field can be introduced where the beam radius would decrease proportionally to the square root of the guiding magnetic field strength.…”