Moderately relativistic high-harmonic gyrotrons for millimeter/submillimeter wavelength band

Bratman, V. L.; Fedotov, A. É.; Kalynov, Yu. K.; Мануилов, В. Н.; Ofitserov, M. M.; Samsonov, S.V.; Savilov, A. V.

doi:10.1109/27.772273

Cited by 92 publications

(20 citation statements)

References 9 publications

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“…7, indicates that the coupling impedance of the lower order harmonic operation is one order stronger than that of the close higher order harmonic operation. More extensive calculation also reveals that such a ten-times relation is also valid in the gyrotron system with large electron beam orbit (r c =0) operation [1,11,12] Fig. 6 The comparisons of the linear growth rate and coupling impedance between (a) unloaded empty waveguide (nonlinear stage), and (b) lossy dielectric-lined waveguide (linear stage).…”

Section: Discussionmentioning

confidence: 87%

Beam-Wave Coupling Strength Analysis in a Gyrotron Traveling-Wave Amplifier

Du¹,

Liu²

2010

J Infrared Milli Terahz Waves

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Mode competition is an important aspect of the stability analysis of a gyrotron traveling-wave amplifier (gyro-TWT). The concept of the coupling impedance is developed in this paper to investigate the beam-wave coupling strength in the electron cyclotron maser (ECM) interaction system. The coupling impedance brings a global consideration to study competition between the absolute instability and the convective instability in the circuit. The research reveals that the coupling impedance is proportional to the phase velocity of the mode, which means the coupling impedance of a mode in the lower k z region is much stronger than the one in the higher k z region. Interesting discussions are also carried out at the end of the paper. The coupling impedance provides an additional dimension of measurement to understand the ECM interaction.

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Section: Discussionmentioning

confidence: 87%

Beam-Wave Coupling Strength Analysis in a Gyrotron Traveling-Wave Amplifier

Du¹,

Liu²

2010

J Infrared Milli Terahz Waves

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“…In our first demonstration experiments [13], a thin rectilinear beam with a particle energy of 300 keV and a current of 30 A was formed as a result of using a cylindrical selector for cutting a small central part from a solid high-current beam emitted from an explosive-emission cathode. A thin beam was driven by a kicker and then the resulting near-axis beam selectively excited (for different values of the operating magnetic field) the operating TE 1,1 -TE 5,1 modes of the cavity at the first five cyclotron harmonics.…”

Section: Prior Experimentsmentioning

confidence: 99%

“…Along with the already realized unique sources such as conventional gyrotrons with very strong magnetic fields [1][2][3][4][5] and free-electron lasers [6,7], the so-called large-orbit gyrotrons (LOGs) [8][9][10][11][12][13][14][15], which previously operated in centimeter-and millimeter-wave ranges, seem to be more promising and, possibly, simpler for the case of submillimeter waves. As opposed to a conventional gyrotron in which electrons move along the helical trajectories whose axes are uniformly distributed over the circumference (or in a thin ring) with radius significantly exceeding the Larmor radius of particles, all particles in the LOGs perform the Larmor rotation round the cavity axis as they move along this axis.…”

Section: Introductionmentioning

confidence: 99%

Submillimeter-wave large-orbit gyrotron

Bratman

Kalynov

Мануилов

et al. 2005

Radiophys Quantum Electron

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We develop a thermionic-emission electron-optical system forming a dense beam of electrons moving along helical trajectories round the axis of a gyrotron cavity. The maximum beam current is 4 A and the pitch-factor of electrons is 1.0 for a particle energy of 250 keV and a pulse duration of 10 µs. Using such a beam in a gyrotron operated at the third cyclotron harmonic, we obtain single-mode oscillation with a power of 10 µs in the T E 3,8 and T E 3,9 modes with frequencies 371 and 414 GHz, respectively.

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“…After a number of experiments [23][24][25][26], LOGs operated at the shortest wavelength were created at the Institute of Applied Physics (IAP) of the Russian Academy of Sciences. In those devices, the electrodynamic system was a conventional (i.e., opened towards the collector) cylindrical gyrotron cavity, which has much better selective properties than the closed cavities used in [2,14,17].…”

Section: Small-and Large-orbit Gyrotronsmentioning

confidence: 99%

Large-orbit Subterahertz and Terahertz gyrotrons

Bratman

Kalynov

Мануилов

2009

Radiophys Quantum El

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We review briefly the main ideas and achievements in the field of physics related to shortwavelength large-orbit gyrotrons, in which the coupling of electrons with the working mode and the discrimination of parasitic modes in the case of resonance at the high cyclotron harmonic are more efficient compared with conventional gyrotrons. The results of studying a new large-orbit gyrotron with moderate electron energies of 50-80 keV and comparatively low magnetic fields of 10.5-14 T are presented. In this gyrotron, high-power single-mode generation was obtained at the second and third cyclotron harmonics in the frequency range 0.55-1.00 THz. The prospects of development and application of short-wavelength large-orbit gyrotrons are discussed. SMALL-AND LARGE-ORBIT GYROTRONSThe conventional gyrotron with many off-axis elec-B B a) b) Fig. 1. Projections of electron trajectories onto the cross section of the cavity in a conventional gyrotron at the fundamental cyclotron resonance (a) and in a LOG at the high cyclotron harmonic (b).tron beamlets [1] and the gyrotron with an axis-encircling electron beam [2] were proposed and demonstrated in 1965 and 1968, respectively. A type of the oscillator with an axis-encircling beam, in which electrons move along helical trajectories around the axis of an axisymmetric electrodynamic system, is called a large-orbit gyrotron (LOG). This name is related to the fact that the LOG is usually operated at the high cyclotron harmonic and, therefore, the magnetic field in it, for the same operating frequency, is lower and the Larmor radius of electrons is greater compared with the conventional "small-orbit" gyrotron which is operated at the fundamental cyclotron resonance or the second cyclotron harmonic (Fig. 1). In the case where the conventional gyrotron and the LOG are operated at the same resonant harmonic, the electron "orbit" in them is the same and is determined by the Larmor radius of the electron in the same magnetic field.It should be emphasized that the conventional gyrotrons are perfect oscillators which provide, in particular, a radiation power of 1 MW in the quasi-continuous-wave regime at a high frequency of 0.17 THz with an efficiency of 50% (see, e.g., [3,4]). Conventional gyrotrons also work in the submillimeter-wave range [5][6][7][8] and recently have been used to overcome a 1-THz frequency when operated at the fundamental cyclotron resonance [9] and the second cyclotron harmonic [10]. At the same time, despite their relatively long history, LOGs have been realized in a comparatively small number of experiments and are still at the stage of fundamental research. Nevertheless, LOGs are still fairly attractive for operation at the high cyclotron harmonics since they ensure a more efficient coupling of electrons with the working-mode field and,

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Moderately relativistic high-harmonic gyrotrons for millimeter/submillimeter wavelength band

Cited by 92 publications

References 9 publications

Beam-Wave Coupling Strength Analysis in a Gyrotron Traveling-Wave Amplifier

Beam-Wave Coupling Strength Analysis in a Gyrotron Traveling-Wave Amplifier

Submillimeter-wave large-orbit gyrotron

Large-orbit Subterahertz and Terahertz gyrotrons

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