The Progress in the Studies of Mode Interaction in Gyrotrons

Sabchevski, S.; Glyavin, M. Yu.; Nusinovich, Gregory S.

doi:10.1007/s10762-022-00845-7

Cited by 12 publications

(5 citation statements)

References 138 publications

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“…Note that in cases of hard excitation, even higher efficiency may be achieved by large detunings. 7 Once L exceeds 3.0 cm, the fluctuation in g beam becomes apparent across the entire B 0 -tuning region. A similar response is observed for g fwd .…”

Section: Comparative Study Of Forward and Backward Components In Nonl...mentioning

confidence: 98%

“…Last but not least, it is worth noting that while most gyrotron devices have predominantly utilized the TE mode, 1,2,7,8 there has been limited exploration 36,37,40,41 into the TM-mode gyrotrons due to the significantly higher start-oscillation current required, stemming from their weaker mode-coupling strength in a classical open-cavity-type gyrotron adopting weakly relativistic electron beams. 58 This might lead some to regard the comparative studies between TE and TM modes in the current study as purely theoretical endeavors.…”

Section: Conclusion and Remarksmentioning

confidence: 99%

“…Gyrotrons, utilizing the electron cyclotron maser interaction to generate coherent radiation, [1][2][3] have been experimentally demonstrated as high-power (up to sub-gigawatt level) and high-frequency (up to the terahertz range) sources. [4][5][6][7][8] These powerful radiation sources have found numerous applications in plasma heating for fusion, communication, sensing, security, and biomedical diagnostics. [9][10][11][12] Based on the feedback mechanism, gyrotron oscillators are traditionally categorized into two types the gyrotron backward-wave oscillator (gyro-BWO) and the gyromonotron.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Intrinsic resonance in gyrotron using non-resonant RF structure

Yang,

Yao,

Chen

et al. 2024

Physics of Plasmas

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Gyromonotrons are typically believed to rely on the convective interaction between the co-propagating beam and wave, with the extended energy-exchanging process stemming from the external feedback. However, numerous studies focusing on both transverse electric (TE) mode and transverse magnetic (TM) mode gyrotrons have consistently shown that beam–wave interactions in weak-feedback systems or even in uniform tubes without any structural feedback can yield a theoretical beam efficiency of more than 30% with major forward-wave output during near-cutoff operation, which is the typical operating condition for gyromonotrons. These intriguing findings raise questions about the actual feedback mechanism of gyromonotrons. In this article, comparative studies on the linear and nonlinear behaviors of uniform-tube gyrotron are investigated. The forward and backward waves are observed to co-generate and exhibit similar characteristics of ultra-slow group velocity under near-cutoff operation. This situation allows the as-generated forward wave to modulate the fresh beam, establishing a new backward-wave-like internal feedback loop. Additionally, the quasi-degenerate nature of the bi-directional propagating waves ensures their intrinsic in-phase relationship. The consequent constructive interference enables the uniform tube to function as a high-Q resonator. These findings are found to be independent of the choices of TE or TM modes, providing valuable insights into the underlying interaction mechanism of gyrotron devices.

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Section: Comparative Study Of Forward and Backward Components In Nonl...mentioning

confidence: 98%

Section: Conclusion and Remarksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Intrinsic resonance in gyrotron using non-resonant RF structure

Yang,

Yao,

Chen

et al. 2024

Physics of Plasmas

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“…The density of the mode spectrum (which increases with frequency) and the finite bandwidth of the resonances are responsible for mode competition-a severe problem in selecting a suitable mode and operating the gyrotron in a single mode regime (i.e., without exciting spurious parasitic modes). This subject is discussed in detail in the recently published comprehensive review paper [36]. At resonance, the electrons of the beam interact efficiently with the operating mode.…”

Section: Beam-wave Synchronism and Brillouin Diagramsmentioning

confidence: 99%

Fundamentals of Electron Cyclotron Resonance and Cyclotron Autoresonance in Gyro-Devices: A Comprehensive Review of Theory

Sabchevski

2024

Applied Sciences

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This paper aims to present some selected fundamentals of the theory of a broad class of gyro-devices in a systematic and consistent manner and with sufficient detail necessary for understanding the underlying physical principles of their operation. The focus of this work is on the derivation and analysis of important invariants (constants of motion), as well as on comments concerning their analytical power and the physical insights they provide.

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“…In other words, the multimode results demonstrate two primary phenomena, i.e., efficiency enhancement and loss decline. In previous publications, [22][23][24][25] the efficiency enhancement in a similar situation was explained as nonlinear excitation of the FH mode in the hard self-excitation regime with the assistance of the SH mode, whereas few studies mentioned the loss situation. In this letter, we find that the oscillation in this regime is not purely self-excitation based on the AI, but an amplification process owing to the CI which accounts for the reduction in the ohmic losses.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Instability Entanglement in the Electron Cyclotron Maser

Gao

et al. 2023

Annalen der Physik

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Investigation of absolute instability (AI) and convective instability (CI) of the electron cyclotron maser has independently led to the birth of gyrotron oscillators and amplifiers. Here, it is demonstrated that these instabilities can form a cooperative relationship owing to the nonlinear behavior of the stimulated electron beam. The CI can be induced in a zero‐drive system with the assistance of AI, and the ohmic losses of all the excited waves inside the system are greatly reduced, which is called “instability entanglement” here. According to the theoretical and experimental study of a 167/330 GHz gyrotron, when instability entanglement occurs, the ohmic dissipation decreases to one‐ninth of the AI‐only condition, and the output power is enhanced by 20%. This discovery is promising for surpassing the ceiling of output power and frequency of gyrodevices placed by ohmic losses.

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The Progress in the Studies of Mode Interaction in Gyrotrons

Cited by 12 publications

References 138 publications

Intrinsic resonance in gyrotron using non-resonant RF structure

Intrinsic resonance in gyrotron using non-resonant RF structure

Fundamentals of Electron Cyclotron Resonance and Cyclotron Autoresonance in Gyro-Devices: A Comprehensive Review of Theory

Instability Entanglement in the Electron Cyclotron Maser

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