Boosted excitation of the fifth cyclotron harmonic based on frequency multiplication in conventional gyrotrons.

We discovered a specific property of the eigenmodes of a cylindrical waveguide, due to which efficient mode excitation at ultrahigh (s=4n+1, n is integer) multiples of the gyrofrequency can be provided by a polyhelical weakly relativistic electron beam, standardly used for gyrotron operation. In the proof-of-principle experiment with a V-band gyrotron driven by a 25-keV, 2-A beam, about 100 mW radiation power at the fifth cyclotron harmonic (0.22 THz) has been detected in the cw regime.

Pulsed magnetic field generation system for laser-plasma research.

An up to 15 T pulsed magnetic field generator in a volume of a few cubic centimeters has been developed for experiments with magnetized laser plasma. The magnetic field is created by a pair of coils placed in a sealed reservoir with liquid nitrogen, installed in a vacuum chamber with a laser target. The bearing body provides the mechanical strength of the system both in the case of co-directional and oppositely connected coils.

Control of sub-terahertz gyrotron frequency by modulation-anode voltage: Comparison of theoretical and experimental results.

This paper presents a comparison of simple self-consistent theory data and experimental results aimed to study the influence of the anode voltage on the frequency of the subterahertz gyrotron with the goal of frequency stabilization. Numerical simulations of the electron beam formation and beam-wave interaction in a 0.26 THz gyrotron are performed.

First experimental tests of powerful 250 GHz gyrotron for future fusion research and collective Thomson scattering diagnostics.

A 250 GHz continuous-wave (CW) gyrotron has been developed at the IAP RAS jointly with GYCOM Ltd., as a prototype of the microwave source for the envisaged prospective nuclear fusion power plants (DEMO). The main applications of such a tube are electron cyclotron resonance heating and electron cyclotron resonance current drive of magnetically confined plasma as well as its diagnostics based on collective Thomson scattering in various reactors for controlled thermonuclear fusion (e.

High-power sub-terahertz source with a record frequency stability at up to 1 Hz.

Many state-of-the-art fundamental and industrial projects need the use of terahertz radiation with high power and small linewidth. Gyrotrons as radiation sources provide the desired level of power in the sub-THz and THz frequency range, but have substantial free-running frequency fluctuations of the order of 10. Here, we demonstrate that the precise frequency stability of a high-power sub-THz gyrotron can be achieved by a phase-lock loop in the anode voltage control.