State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2012. (KIT Scientific Reports ; 7641)

This report gives an update of the worldwide experimental achievements in the development of long-pulse gyrotron oscillators for fusion plasma heating, plasma diagnostics and materials processing. In addition, this work gives a short overview of the present development status of coaxial-cavity multi-megawatt gyrotrons, gyrotrons for technological and spectroscopy applications, relativistic gyrotrons, quasi-optical gyrotrons, cyclotron autoresonance masers, gyro-amplifiers, gyro-BWO\u27s, free electron masers and of vacuum windows for such high-power mm-wave sources

State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2016 (KIT Scientific Reports ; 7735)

This report reviews the current experimental state-of-the-art of megawatt-class gyrotrons for fusion plasma heating. In addition, it summarizes the status of frequency-tunable gyrotrons, multi-megawatt gyrotrons with coaxial resonator, gyrotrons for technological and spectroscopic applications, relativistic gyrotrons, cyclotron-autoresonance-masers, gyroklystrons, gyro-TWT-and gyrotwystron-amplifiers, gyro-BWOs, gyro-harmonic-convertors gyro-peniotrons, magnicons, and free-electron-masers

State-of-the-Art of High-Power Gyro-Devices. Update of Experimental Results 2021

This report presents an update of the experimental achievements published in the review “State- of-the-Art of High-Power Gyro-Devices and Free Electron Masers”, Journal of Infrared, Millime-ter, and Terahertz Waves, 41, No. 1, pp 1-140 (2020) related to the development of gyro-devices (Tables 2-34). Emphasis is on high-power gyrotron oscillators for long-pulse or continuous wave (CW) operation and pulsed gyrotrons for any applications

Gyro-devices – natural sources of high-power high-order angular momentum millimeter-wave beams

The Orbital Angular Momentum (OAM) carried by light beams with helical phasefront (vortex beams) has been widely employed in many applications such as optical tweezers, optical drives of micro-machines, atom trapping, and optical communication. OAM provides an additional dimension (diversity) to multiplexing techniques, which can be utilized in addition to conventional multiplexing methods to achieve higher data rates in wireless communication. OAM beams have been thoroughly studied and used in the optical regime but in the mm-wave and THz-wave region, they are still under investigation. In these frequency bands, there are difficulties associated with beam-splitting and beam-combining processes as well as with the use of spiral phase plates and other methods for OAM generation, since the wavelength is much larger compared to those at optical frequencies, leading to higher diffraction losses. The present paper describes the natural generation of high-power OAM modes by gyro-type vacuum electron devices with cylindrical interaction circuit and axial output of the generated rotating higher-order transverse electric mode TEm,n, where m > 1 and n are the azimuthal and radial mode index, respectively. The ratio between the total angular momentum (TAM) JN and total energy WN of N photons is given by m/ω, where ω is the angular frequency of the operating mode, which in a gyrotron oscillator is close to the TEm,n-mode cutoff frequency in the cavity. Therefore, m/ω = Rc/c, where Rc is the caustic radius and c the velocity of light in vacuum. This means that the OAM is proportional to the caustic radius and at a given frequency the same for all modes with the same azimuthal index m. Right-hand rotation (co-rotation with the electrons) corresponds to a positive value of m and left-hand rotation to negative m. The corresponding OAM mode number (topological charge) is l = m – 1. Circularly polarized TE1n modes only possess a Spin Angular Momentum (SAM: s = ±1). TE0n modes have neither SAM nor OAM. This is the result of the photonic (quasi-optical) approach to derive the TAM of modes generated in gyrotrons. The same result follows from the electromagnetic (EM) wave approach for the TAM within a given waveguide volume per total energy of the EM wave in the same volume. Such high-power output beams with very pure higher-order OAM, generated by gyrotron oscillators or amplifiers (broadband) could be used for multiplexing in long-range wireless communications. The corresponding mode and helical wavefront sensitive detectors for selective OAM-mode sorting are available and described in the present paper

State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2010. (KIT Scientific Reports ; 7575)

This report gives an update of the worldwide experimental achievements in the development of long-pulse gyrotron oscillators for fusion plasma heating, plasma diagnostics and materials processing. In addition, this work gives a short overview of the present development status of coaxial-cavity multi-megawatt gyrotrons, gyrotrons for technological and spectroscopy applications, relativistic gyrotrons, quasi-optical gyrotrons, cyclotron autoresonance masers, gyro-amplifiers, gyro-BWO\u27s, free electron masers and of vacuum windows for such high-power mm-wave sources

Design Procedure for a Broadband TE11/HE11 Mode Converter for High-Power Radar Applications

The HE$_{11}$ hybrid mode, propagating in an overmoded corrugated circular waveguide, is widely used for low loss transmission of high-power microwaves. Due to the inherent broadband frequency behaviour, this will be also essential for future broadband high-power radar applications, like space debris observation in low earth orbit (LEO). A promising amplifier concept for such radar sensors is a helical gyro-TWT. However, since the HE$_{11}$ hybrid mode is not suitable for electron-beam-wave interaction in this kind of vacuum electron device, an additional mode converter is required. The present paper addresses the design procedure of a broadband high-power mode converter, designed for a helical gyro-TWT intended for future broadband high-power radar applications in the W-band. The interaction mode of the helical gyro-TWT under consideration can be easily transferred to the circular waveguide TE$_{11}$ mode. Therefore, a TE$_{11}$ ↦ HE$_{11}$ mode converter is addressed here. The design procedure is based on a scattering matrix formalism and leads to a high HE$_{11}$ mode content of ≥98.6% within the considered frequency range from 92 GHz to 100 GHz. Inside this frequency band, the mode content is even better and reaches ≈ 99.7% at ≈95 GHz. This allows broadband frequency operation of a helical gyro-TWT and is suitable for broadband high-power radar applications

On the Elementary Mechanical Effects of the Space-Time-Symmetry Relativity

This paper is an addendum to the article “On the Evolution of Approaches to the Space- Time Symmetry”, Natural Science, Vol. 10, No. 3, pp. 81-84, 2018. The analysis is based on the Galileo’s postulate that all inertial reference frames are equal. The postulate results immediately in the absolute speed limit, which is identical for all bodies in all reference frames. Two kinds of elementary particles are admitted: unhurried and restless ones (ex-emplified, accordingly, with electrons and photons). Any particle may be treated as wave packet, the particle mass and momentum depending on the reference frame. Thus, space-time-symmetry is the natural background for the relativistic and quantum theories

State-of-the-Art of High Power Gyro-Devices and Free Electron Masers. Update 2014. (KIT Scientific Reports ; 7693)

Dieser Bericht geht auf den experimentellen Stand von Hochleistungs-Gyrotrons für verschiedene Anwendungen ein. Außerdem wird über frequenzdurchstimmbare Gyrotrons, Multi-MW-Gyrotrons mit koaxialem Resonator, Gyrotrons für technologische und spektroskopische Anwendungen, relativistische Gyrotrons, Zyklotron-Autoresonanz-Maser, Gyroklystrons, Gyro-TWT-und Gyrotwystron-Verstärker, Gyro-RWO, Gyro-Peniotrons, Magnicons, Gyro-Harmonische-Konvertoren u. Frei-Elektronen-Laser berichtet