Phase-Locking of Second-Harmonic Gyrotrons for Providing MW-Level Output Power

Денисов, Г. Г.; Zotova, I. V.; Zheleznov, I. V.; Malkin, A. M.; Sergeev, A. S.; Semenov, E. S.; Glyavin, M. Yu.

doi:10.1109/ted.2021.3134187

Cited by 9 publications

(3 citation statements)

References 27 publications

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“…This relaxes significantly the possibly challenging requirements for the insert cooling in CW operation. In addition, the presented method is much less complex compared to that in [13] since no additional gyrotrons are required to provide an external signal for the excitation of the operating second-harmonic mode.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the excitation of high-order modes at 340 GHz with output power of the order of 100 kW CW has been theoretically demonstrated [11], and, more recently, second-harmonic operation at 60 GHz with output power at the level of hundreds of kilowatt has been investigated [12]. Regarding megawatt-level second-harmonic operation, the possibility of employing the injection locking concept, where an external signal is injected in the cavity to "lock" the operating mode and favor its excitation, has been theoretically studied in [13]. The injection locking concept seems promising for second-harmonic operation and has been experimentally demonstrated for short-pulse first-harmonic operation recently [14], however requiring an auxiliary gyrotron driving the main tube, thus increasing the complexity and the overall cost of the necessary infrastructure.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Design of MW-Class Coaxial Gyrotron Cavities With Mode-Converting Corrugation Operating at the Second Cyclotron Harmonic

Peponis,

Avramidis,

Chelis

et al. 2023

IEEE Trans. Electron Devices

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This article presents investigations on the design of coaxial gyrotron cavities with mode-converting corrugations, operating at the second harmonic of the electron cyclotron frequency with output power of the order of megawatts. The suppression of the competing modes interacting at the fundamental cyclotron frequency is achieved by the combination of a corrugated coaxial insert and mode-converting corrugation on the outer wall. The outer corrugation couples the key competing modes to lower order modes with reduced quality factor. The design steps, which form a generally applicable design procedure, are described in detail. As an illustrative example, the proposed procedure is used for the design of a cavity for a fusionrelevant, second-harmonic MW-class gyrotron, operating at 170 GHz with the TE 37,18 mode. From the simulations, it is found that for the proposed design, this mode is excited with an output power of around/∼1.5 MW. Two additional paths for cavity optimization toward even higher output power are also presented.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design of MW-Class Coaxial Gyrotron Cavities With Mode-Converting Corrugation Operating at the Second Cyclotron Harmonic

Peponis,

Avramidis,

Chelis

et al. 2023

IEEE Trans. Electron Devices

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show abstract

“…Furthermore, since the interaction at the second harmonic is inherently weaker than the interaction at the fundamental for a given field amplitude level, the operating second-harmonic mode faces strong mode competition from its first-harmonic competitors. For example, in [10], the concept of injection locking was employed as a means for enhancing mode selectivity and exciting, in simulation, the second-harmonic mode TE 34,14 up to 0.9 MW at 230 GHz with an external signal of 50 kW. However, this approach exhibits increased complexity, since it requires an additional source of medium-power radiation of the same frequency, which also needs to be highly stable.…”

Section: Introductionmentioning

confidence: 99%

High-Frequency MW-class Coaxial Gyrotron Cavities Operating at the Second Cyclotron Harmonic

Chelis,

Avramidis,

Peponis

et al. 2024

IEEE Trans. Electron Devices

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Second-harmonic operation of gyrotron oscillators offers the possibility to generate millimeter and submillimeter radiation at half the value of the magnetic field required for operation at the fundamental cyclotron frequency (first harmonic). However, being inherently weaker than the interaction at the first harmonic, highpower second-harmonic continuous-wave (CW) operation employing high-order modes faces strong mode competition from the first-harmonic competing modes. It is shown that coaxial cavities with a corrugated insert allow to drastically enhance the mode selectivity at the second harmonic and suppress the first-harmonic competitors in MW-class gyrotrons. Detailed design considerations for coaxial cavities are presented and specific cavity designs for various candidate operating modes are given. We demonstrate numerically, with multimode interaction simulations, stable second-harmonic CW generation of 2 MW output power at 170 GHz and 0.7 MW at 280 GHz, using high-order modes with eigenvalues >100. The presented results show the possibility to design second-harmonic gyrotrons with cost-effective magnet systems and achieve MW-class CW operation at frequencies above 250 GHz.

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Effect of Non-Ideal Electron Beam Characteristics on the Performance of a Megawatt-Power Gyrotron with an External Monochromatic Signal

Bakunin

Glyavin

Денисов

et al. 2023

J Infrared Milli Terahz Waves

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Phase-Locking of Second-Harmonic Gyrotrons for Providing MW-Level Output Power

Cited by 9 publications

References 27 publications

Design of MW-Class Coaxial Gyrotron Cavities With Mode-Converting Corrugation Operating at the Second Cyclotron Harmonic

Design of MW-Class Coaxial Gyrotron Cavities With Mode-Converting Corrugation Operating at the Second Cyclotron Harmonic

High-Frequency MW-class Coaxial Gyrotron Cavities Operating at the Second Cyclotron Harmonic

Effect of Non-Ideal Electron Beam Characteristics on the Performance of a Megawatt-Power Gyrotron with an External Monochromatic Signal

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