A co-harmonic gyro-monotron with a novel corrugated interaction cavity

A novel interaction cavity has been designed for a gyro-monotron, allowing co-harmonic generation at the 2nd and 4th harmonic resonances of the cyclotron frequency. The output aperture of the cavity has been designed to trap the lower harmonic, whilst allowing output of the upper harmonic. Results from recent numerical simulations, performed using MAGIC 3-D, are presented. The intended co-harmonic behaviour is observed, with simultaneous excitation of the 2nd and 4th harmonics. Refinement of the output structure is now being undertaken to ensure only the 4th harmonic signal is emitted

A co-harmonic gyro-oscillator with a novel interaction cavity

A novel interaction cavity has been designed for a gyro-oscillator, allowing co-harmonic generation at the 2(nd) and 4(th) harmonic resonances of the cyclotron frequency. The output aperture of the cavity has been designed to trap the lower harmonic, whilst allowing output of the upper harmonic. Results from recent numerical simulations, performed using MAGIC 3-D, are presented. The intended co-harmonic behaviour is observed, with simultaneous excitation of the 2(nd) and 4(th) harmonics. Refinement of the output structure is now being undertaken to ensure only the 4(th) harmonic signal is emitted

Two dimensional Bragg structures (modeling and experimental testing selective properties)

The analysis of electrodynamic properties of two-dimensional (2D) Bragg resonators of planar and coaxial geometry realizing 2D distributed feedback was carried out in the frame of the coupled-mode approach and in 3D simulations taken into account. High selectivity of above structures is demonstrated for large Fresnel parameters. Formation of the high-Q eigenmodes in the vicinity of the Bragg resonance frequency has been demonstrated and explained by peculiarities of the dispersion characteristics of normal waves. Parameters of the resonator when the Q-factor of the fundamental mode exceeds the Q-factor of all other modes is described. The results of 3D simulations of excitation of the fundamental mode by an external e.m. pulse using the 3D code Microwave Studio are presented. Results of the theoretical analysis corroborated by the data obtained in "cold" microwave measurements

Production of powerful spatially coherent radiation in planar and coaxial fem exploiting two-dimensional distributed feedback

Two-dimensional distributed feedback is an effective method of producing ultrahigh-power spatially coherent radiation from an active medium, that is spatially extended along two coordinates, including relativistic electron beams with sheet and annular geometry. This paper describes the progress in the investigations of planar and coaxial free-electron masers (FEMs) based on a novel feedback mechanism. The theoretical analysis of these FEM schemes was conducted in the frame of the coupled-wave approach and 3-D simulations and agrees well with the experimental data obtained in ldquocoldrdquo and ldquohotrdquo tests. As a result, the effective transverse (azimuthal) mode selection has been demonstrated under a transverse size of about 20-25 wavelengths, and narrow-frequency multimegawatt microwave pulses have been generated in the Ka- and W-bands