Gyrotron Traveling Wave Amplifier with a Helical Interaction Waveguide

Денисов, Г. Г.; Bratman, V. L.; Cross, Adrian W.; He, Wenlong; Phelps, A. D. R.; Ronald, K.; Samsonov, S.V.; Whyte, C.G.

doi:10.1103/physrevlett.81.5680

Cited by 218 publications

(88 citation statements)

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“…Most of the work on gyro-devices has involved helical waveguide interaction structures [1,2]. This interest began in the 1990's stimulated by collaborative research with IAP.…”

Section: Gyro-devicesmentioning

confidence: 99%

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Progress in microwave to sub-THz sources at Strathclyde

Phelps

2017

EPJ Web Conf.

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Research progress during recent years at the University of Strathclyde is presented. The main research themes include gyro-devices with particular emphasis on gyro-TWAs [1,2] and gyro-BWOs, and natural sources of radiation such as auroral kilometric radiation (AKR) [3][4][5][6], novel Cherenkov mm-wave sources [7,8] and pseudospark-driven sub-THz sources [9][10][11].While there has been some theoretical work, the majority of the research has involved either laboratory experiments, or numerical simulations. Gyro-devicesMost of the work on gyro-devices has involved helical waveguide interaction structures [1,2]. This interest began in the 1990's stimulated by collaborative research with IAP. The early experiments were in the 10GHz frequency range, whereas our more recent experiments have been in the 90 to 100 GHz range. The applications for these mm-wave amplifiers include DNP-NMR, cloud radar and communications, etc. Fig. 1. Gyro-TWA, 90 -100 GHzThe gyro-TWA shown in Fig. 1 has produced 3.4kW output power. The limit on the output power is presently the maximum power that is available at the input to the amplifier. Natural sources of EM radiationPrevious research on laboratory gyro-devices and electron cyclotron masers has provided the background for investigations of the mechanism of some naturally occurring sources of electromagnetic radiation. A research programme stretching over more than 10 years has explored the detailed mechanism of auroral kilometric radiation (AKR) and similar emissions emanating from other astrophysical bodies. Laboratory experiments to simulate the natural phenomena, combined with theoretical analysis and numerical modelling have been compared with natural observations. Using all four approaches it has been possible to understand how AKR arises and the mechanism by which the energy in electron streams can be converted with 1% or 2% efficiency into AKR. The mechanism depends upon the existence of an anisotropy in velocity space. This anisotropy is created when electrons are spiralling down the magnetospheric field lines. The magnetic moment is an adiabatic invariant of the electron motion and as the electrons penetrate further into the increasing magnetic field the electrons increase the perpendicular component of their velocity and decrease the component of their velocity parallel to the magnetic field lines. This results in a horseshoe shaped particle distribution in velocity space. The positive value of the gradient with respect to the perpendicular velocity component of the distribution function drives this kinetic instability that is now known as the "horseshoe instability". The theoretical analysis, the PiC simulations, the laboratory experiment and the space observations all agree. Fig. 2. Cylindrical over-sized Cherenkov structure Cherenkov sourcesOne of the aims of the research on Cherenkov sources is to retain reasonably high output power levels as the frequency increases. Traditionally Cherenkov sources have followed the trend that as the frequency increases and the wavelength...

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“…Most of the work on gyro-devices has involved helical waveguide interaction structures [1,2]. This interest began in the 1990's stimulated by collaborative research with IAP.…”

Section: Gyro-devicesmentioning

confidence: 99%

“…The main research themes include gyro-devices with particular emphasis on gyro-TWAs [1,2] and gyro-BWOs, and natural sources of radiation such as auroral kilometric radiation (AKR) [3][4][5][6], novel Cherenkov mm-wave sources [7,8] and pseudospark-driven sub-THz sources [9][10][11].…”

mentioning

confidence: 99%

Progress in microwave to sub-THz sources at Strathclyde

Phelps

2017

EPJ Web Conf.

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“…and even in the vacuum electronic devices, such as, linear/particle accelerators [11,12], backward-wave oscillators (BWOs) [13], magnetrons [14], coupledcavity and helix travelling-wave tubes (TWTs) [15][16][17][18][19], cyclotron masers [20,21], gyrotron sources [21][22][23][24] and amplifiers [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39], etc.. In these devices, one may see the periodic beam-wave interaction structures holding either azimuthal or axial periodicity [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]…”

Section: Introductionmentioning

confidence: 99%

“…The azimuthal periodicity in interaction structure may be seen, for example: in travelling-wave magnetrons [14] for π-mode operation, in gyrotrons [21][22][23][24] for mode rarefaction, in conventional helixTWTs [17] for broadbanding, in gyro-travelling wave tubes (gyroTWTs) [25,26] for higher interaction impedance and, in turn, for higher device-gain. The axial periodicity in interaction structure may be seen, for example, in conventional helix-TWT [17] for higher device-gain, in coupled-cavity TWT [17] for getting fundamentalmode backward-wave characteristics, and in gyro-TWT [27][28][29][30][31][32][33][34][35][36][37][38][39] for broadbanding.…”

Section: Introductionmentioning

confidence: 99%

Propagation Characteristics of a Variant of Disc-Loaded Circular Waveguide

Kesari¹,

Keshari²

2012

PIER M

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Abstract-The shaping of dispersion characteristics in a variant of disc-loaded circular waveguide was studied through electromagnetic analysis for assessing the structure for wideband coalescence of the beam-and waveguide-mode dispersion characteristics that entails the wideband gyro-travelling-wave tube (gyro-TWT) performance. In this variant of disc-loaded circular waveguide, the alternate dischole radii were varying, however, the structure was periodic. The structure periodicity coupled with Floquet's theorem and fieldmatching technique resulted into the dispersion relation of the infinitely long structure. A numerical code was developed to solve the dispersion relation, and the dispersion characteristics of the structure were analyzed for the azimuthally symmetric TE-modes. The effects of structure parameters were studied for getting a straight-line portion of the dispersion characteristics over a wide frequency range. The dispersion shaping was projected for typically chosen TE 01 -mode. The results were validated against those obtained for the conventional and un-conventional known structures and those obtained using commercially available simulation tool. The variation of azimuthal electric field intensity over the radial coordinate was also studied to examine the control of structure parameter for maxima-position, where the gyrating electron beam would be positioned for optimum beamwave interaction in a gyro-TWT.

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“…9 This allows broadband microwave amplification to be achieved in a gyrotron traveling wave amplifier. 10,11 Such a system is also favorable when used in a gyro-BWO ͑Ref. 12͒ in two ways.…”

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confidence: 99%

Theory and simulations of a gyrotron backward wave oscillator using a helical interaction waveguide

Cross

Phelps

et al. 2006

Applied Physics Letters

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This version is available at https://strathprints.strath.ac.uk/10168/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.Theory and simulations of a gyrotron backward wave oscillator using a helical interaction waveguide A gyrotron backward wave oscillator ͑gyro-BWO͒ with a helically corrugated interaction waveguide demonstrated its potential as a powerful microwave source with high efficiency and a wide frequency tuning range. This letter presents the theory describing the dispersion properties of such a waveguide and the linear beam-wave interaction. Numerical simulation results using the PIC code MAGIC were found to be in excellent agreement with the output measured from a gyro-BWO experiment.

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Gyrotron Traveling Wave Amplifier with a Helical Interaction Waveguide

Cited by 218 publications

References 6 publications

Progress in microwave to sub-THz sources at Strathclyde

Progress in microwave to sub-THz sources at Strathclyde

Propagation Characteristics of a Variant of Disc-Loaded Circular Waveguide

Theory and simulations of a gyrotron backward wave oscillator using a helical interaction waveguide

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