Multimegawatt relativistic harmonic gyrotron traveling-wave tube amplifier experiments

Menninger, W.L.; Danly, B.G.; Temkin, R.J.

doi:10.1109/27.533070

Cited by 28 publications

(5 citation statements)

References 26 publications

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“…More recently, Menninger et al at MIT reported 4 MW at 17.1 GHz in a 20-ns output pulse at 6.5% efficiency, with 51 dB of gain, from a gyro-TWT that operated in the third cyclotron harmonic, using a 380-keV, 160-A electron beam from a thermionic electron gun driven by an induction accelerator. 164 Unlike the gyrotron, the frequency of the cyclotron autoresonance maser ͑CARM͒ scales upwards in frequency as the voltage is increased, since the relativistic frequency upshift (ϳ␥ 2 ) more than cancels the relativistic decrease of the electron gyrofrequency (␥ Ϫ1 ), producing an overall ␥ scaling of the output frequency. However, like FELs and unlike gyrotrons, the presence of the Doppler term in the resonance condition makes CARM devices very sensitive to spreads in electron axial velocity ͑though they are insensitive to spreads in electron energy͒.…”

Section: Relativistic Gyrodevicesmentioning

confidence: 99%

Review of high-power microwave source research

Gold

Nusinovich

1997

Review of Scientific Instruments

359

138

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This article reviews the state-of-the-art in high-power microwave source research. It begins with a discussion of the concepts involved in coherent microwave generation. The main varieties of microwave tubes are classified into three groups, according to the fundamental radiation mechanism involved: Cherenkov, transition, or bremsstrahlung radiation. This is followed by a brief discussion of some of the technical fundamentals of high-power microwave sources, including power supplies and electron guns. Finally, the history and recent developments of both high-peak power and high-average power sources are reviewed in the context of four main areas of application: ͑1͒ plasma resonance heating and current drive; ͑2͒ rf acceleration of charged particles; ͑3͒ radar and communications systems; and ͑4͒ high-peak power sources for weapons-effect simulation and exploratory development.

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Section: Relativistic Gyrodevicesmentioning

confidence: 99%

Review of high-power microwave source research

Gold

Nusinovich

1997

Review of Scientific Instruments

359

138

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“…Other phase-sensitive applications include coherent radars, communication systems, accelerators, and linear colliders. The phase stability of gyro-amplifiers has been the subject of intensive theoretical and experimental research [5][6][7][8][9][10][11][12][13][14][15], but thus far it has only been measured up to W-band, for any amplifier. Existing techniques are challenging at higher frequencies because of high ohmic loss in fundamental waveguides and limited availability of crucial components, such as a balanced mixer.…”

Section: Introductionmentioning

confidence: 99%

Phase Measurements of a 140-GHz Confocal Gyro-Amplifier

Rosenzweig

Jawla

Picard

et al. 2020

J Infrared Milli Terahz Waves

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The phase stability of a 140-GHz, 1-kW pulsed gyro-amplifier system and the phase dependence on the cathode voltage were experimentally measured. To optimize the measurement precision, the amplifier was operated at 47 kV and 1 A, where the output power was ∼ 30 W. The phase was determined to be stable both pulseto-pulse and during each pulse, so far as the cathode voltage and electron beam current are constant. The phase variation with voltage was measured and found to be 130 ± 30 • /kV, in excellent agreement with simulations. The electron gun used in this device is non-adiabatic, resulting in a steep slope of the beam pitch factor with respect to cathode voltage. This was discovered to be the dominant factor in the phase dependence on voltage. The use of an adiabatic electron gun is predicted to yield a significantly smaller phase sensitivity to voltage, and thus a more phase-stable performance. To our knowledge, these are the first phase measurements reported for a gyro-amplifier operating at a frequency above W-band.

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“…In order to eliminate this problem, operation at the second cyclotron harmonic is widely adopted since the strength of the magnetic field for second cyclotron harmonic operation is only half of that for the fundamental cyclotron harmonic. It is this reason that the FEM operating at the second cyclotron harmonic has been widely developing in the world [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In this way the working frequency of a FEM has been extended to the far-infrared range of 300-600 GHz [7,9,11,19].…”

Section: Introductionmentioning

confidence: 99%

A far-infrared free-electron maser oscillator operating at the third cyclotron harmonic

Ouyang

Zhang

2002

J. Phys. B: At. Mol. Opt. Phys.

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In this paper the feasibility of a far-infrared free-electron maser oscillator is demonstrated, which can be expected to operate in a single mode at the third cyclotron harmonic, with the advantages of low magnetic field and entire suppression of the competition modes. It is found that compared to the second cyclotron harmonic operation, the third cyclotron harmonic operation has positive advantages. By making use of the gyrokinetic formulae, typical parameters are optimized.

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Multimegawatt relativistic harmonic gyrotron traveling-wave tube amplifier experiments

Cited by 28 publications

References 26 publications

Review of high-power microwave source research

Review of high-power microwave source research

Phase Measurements of a 140-GHz Confocal Gyro-Amplifier

A far-infrared free-electron maser oscillator operating at the third cyclotron harmonic

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