Search

This paper aims to present some selected fundamentals of the theory of a broad class of gyro-devices in a systematic and consistent manner and with sufficient detail necessary for understanding the underlying physical principles of their operation. The focus of this work is on the derivation and analysis of important invariants (constants of motion), as well as on comments concerning their analytical power and the physical insights they provide. [ABSTRACT FROM AUTHOR]

This paper aims to present some selected fundamentals of the theory of a broad class of gyro-devices in a systematic and consistent manner and with sufficient detail necessary for understanding the underlying physical principles of their operation. The focus of this work is on the derivation and analysis of important invariants (constants of motion), as well as on comments concerning their analytical power and the physical insights they provide.

Gyrotrons are used as high-power sources of coherent radiation operating in pulsed and CW regimes in many scientific and technological fields. In this paper, we discuss two of their numerous applications. The first one is in gyrotron-powered electromagnetic wigglers and undulators. The second one is for driving high-gradient accelerating structures in compact particle accelerators. The comparison, between the requirements imposed by these two concepts on the radiation sources on one hand and the output parameters of the currently available high-performance gyrotrons on the other hand, show that they match each other to a high degree. We consider this as a manifestation of the feasibility and potential of these concepts. It is believed that after the first successful proof-of-principle experiments they will find more wide usage in the advanced FEL and particle accelerators. [ABSTRACT FROM AUTHOR]

Gyrotrons are used as high-power sources of coherent radiation operating in pulsed and CW regimes in many scientific and technological fields. In this paper, we discuss two of their numerous applications. The first one is in gyrotron-powered electromagnetic wigglers and undulators. The second one is for driving high-gradient accelerating structures in compact particle accelerators. The comparison, between the requirements imposed by these two concepts on the radiation sources on one hand and the output parameters of the currently available high-performance gyrotrons on the other hand, show that they match each other to a high degree. We consider this as a manifestation of the feasibility and potential of these concepts. It is believed that after the first successful proof-of-principle experiments they will find more wide usage in the advanced FEL and particle accelerators.

In this paper, techniques to improve the collector’s dissipated power density threshold are discussed first. Then, theories of electron collection are presented, aiming at improving the effective electron-collecting area and collecting uniformity. Specifically, the layered electron beam collection in linear-taper collector, respectively, with constant and gradually varying magnetic field is modeled and discussed. Results indicate that a quasi-rectangular shape collection can be realized as the tangential collection dominates. Finally, the using of a compensation coil is analyzed and the corresponding collector is designed. [ABSTRACT FROM AUTHOR]

The global bandgaps of photonic crystal are theoretically analyzed in this paper. The electromagnetic-wave propagation characteristics of photonic bandgap (PBG) structures, which is used in the the millimeter-wave, submillimeter-wave, and terahertz regime vacuum electronic devices and accelerators, were numerically simulated using the finite-element method software high-frequency structural simulator. The dispersion curves of the lattices in different rod radius to-rod spacing ratios and the global bandgaps for the general 2-D PBG structures formed by triangular and square arrays of metal rods were simulated. A mode map that shows the relationship between the structures and the contained modes was plotted and a 220-GHz metallic PBG resonator operating in TE \mathrm {\mathbf {04}} mode was designed for a gyrotron device to verify the theoretical and numerical simulations, and a comparison of mode density and quality factor between the PBG resonator and the equivalent cylindrical resonator has been carried out. [ABSTRACT FROM PUBLISHER]

The gyro-BWO is a UHF powerful oscillator for cm and mm band of wavelength in which relativistic electrons beam is used for coupling with a backward wave on normal Doppler effect. The first research of gyro-devices was published in 60th. Possible applications of gyro-devices UHF radiation are the followings: electron cyclotron resonance heating of plasma for controlled fusion, communication, spectroscopic researches, high-resolution radars etc. Investigations of gyro-BWO confirm that an essential limitation of the considered device is the small efficiency. One of possibilities for efficiency enhancing is to use profiling guiding magnetic field along an interaction region. We investigated dependence of efficiency increasing under using optimal profiling guiding magnetic field by special law. As a result of effective process bunch formation under special conditions most electrons can be confined in the energy-losing phase HF field. Efficiency enhancement takes place from initial value for homogenous guiding field to for profiling one.