Theory of non-stationary processes in gyrotrons with low Q resonators

Ginzburg, N. S.; Nusinovich, G. S.; Zavolsky, N. A.

doi:10.1080/00207218608920927

Cited by 175 publications

(81 citation statements)

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“…In this paper, we present the first detailed and systematic experimental characterization of different operating regimes, from linear to chaotic over a wide range of system parameters which will be summarized in the normalized ðD À IÞ plane with D and I being the normalized detuning and current, 9 respectively. After the seminal work by Ginzburg et al, 15 Airila et al 2 used a numerical approach to study non linear effects in gyro devices and presented their findings in the ðD À IÞ plane. The comparison with our results confirms the different nonstationary regimes analysed in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…These theoretical studies were made on advanced models based on the slow-time scale formulation of the selfconsistent interaction equations 1,2,7,8,15,27 or on more firstprinciple set of equations solved using a particle in cell approach. 16,17,22 Experimental studies have been carried out by Chang et al 10 and more recently on a system where delayed feedback mechanisms were introduced for accessing to chaotic regimes.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

et al. 2012

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Basic wave-particle interaction dynamics from linear to chaotic regimes is experimentally studied on a frequency tunable gyrotron generating THz radiation in continuous mode (200 W) at 263 GHz which will be used for dynamic nuclear polarization nuclear magnetic resonance spectroscopy applications. In the studied system, the nonlinear dynamics associated to the waveparticle interaction is dominated by longitudinal mode competition of a given transverse TE m;p cavity-mode. This study covers a wide range of control parameter from gyro-traveling wave tube (gyro-TWT) to gyro-backward wave oscillator (gyro-BWO) like interactions for which extensive theoretical studies have been performed in the past on a simplified system. Besides the common route to chaos characterized by period doubling, other routes have been identified among which some are characterized by line-width frequency-broadening on the side-bands. The complex nonlinear dynamics is in good agreement with the theory and the experimental results are discussed on the basis of the prediction obtained with the nonlinear time-dependent selfconsistent codes TWANG and EURIDICE both based on a slow-time scale formulation of the self-consistent equations governing the wave-particle dynamics. V C 2012 American Institute of Physics. [http://dx

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

et al. 2012

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“…Будем считать, что на входе в простран-ство взаимодействия электроны равномерно распределены по фазам циклотронного вращения p(Z = 0) = e iθ 0 , θ 0 ∈ [0, 2π]. При этом во входном и выходном сечениях волновода использовались излучательные граничные условия [10].…”

Section: поступило в редакцию 18 мая 2017 гunclassified

Генерация Ультракоротких Импульсов Субтерагерцевого И Терагерцевого Диапазонов На Основе Эффекта Циклотронного Сверхизлучения

Розенталь¹,

Гинзбург²,

Зотова³

et al. 2017

Письма В Журнал Технической Физики

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В рамках усредненного описания электронно-волнового взаимодействия, а также на основе прямого моделирования PIC (particle in cell) показана возможность генерации ультракоротких импульсов субтерагерцевого и терагерцевого диапазонов с использованием циклотронного механизма сверхизлучения (СИ) сгустков электронов, движущихся по винтовым траекториям в однородном магнитном поле. В условиях существенной сверхразмерности волноводного тракта селективное возбуждение рабочей моды обеспечивается при движении электронного сгустка с поступательной скоростью, близкой к групповой скорости излучаемого импульса СИ. DOI: 10.21883/PJTF.2017.18.45030.16878

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“…where the most normalized variables are the same as in the previous gyrotron model [3], At the system input and output we apply the well-known reflectionless boundary condition [3]. In Fig.…”

Section: Mechanism Of Rogue Waves Generationmentioning

confidence: 99%

“…For theoretical analysis of rogue waves generation in gyrotrons we have generalized the self-consistent timedomain model of low-Q gyrotrons [3] in the frame of which the evolution of the field amplitude is described by a non-uniform parabolic equation. In the novel model, first of all an inclination of the beam line with respect to the dispersion characteristic of the waveguide mode is taken into account [4], because the maximum spectrum bandwidth of chaotic generation, including rogue waves, is determined by the difference between resonances with backward and forward waves (points 1 and 2 in Fig.…”

Section: Mechanism Of Rogue Waves Generationmentioning

confidence: 99%

Generation of rogue waves in gyrotrons with high excess over the threshold

et al. 2017

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Many physical systems exhibit behavior associated with the emergence of the so-called rogue waves which represent dramatically high-amplitude events that occur with low probability but much more frequently than expected in ordinary wave statistics [1]. For example, in laser physics and optics rogue waves arise in the process of supercontinuum generation and represent pulses of ultra broadband light with extremely high peak power [2]. In this paper within the framework of the average approach and in direct 3D PIC (particle-in-cell) simulations we demonstrate that rogue waves can also appear in gyrotrons operating with high excess over the threshold. The mechanism of extreme spikes formation is related to simultaneous cyclotron interaction of a gyrating electron beam with forward and backward waves near the waveguide cutoff frequency as well as with the longitudinal deceleration of electrons. From the practical point of view, experimental observation of the rogue waves generation in gyrotrons can be interesting as a method for production of high-power millimeter-wave radiation with an ultra broadband spectrum. The required exceeding over the threshold can be achieved for routine parameters of the driving electron beams formed by the magnetroninjection guns due to operation at the lowest modes of microwave cavities. Mechanism of Rogue Waves GenerationFor theoretical analysis of rogue waves generation in gyrotrons we have generalized the self-consistent timedomain model of low-Q gyrotrons [3] in the frame of which the evolution of the field amplitude is described by a non-uniform parabolic equation. In the novel model, first of all an inclination of the beam line with respect to the dispersion characteristic of the waveguide mode is taken into account [4], because the maximum spectrum bandwidth of chaotic generation, including rogue waves, is determined by the difference between resonances with backward and forward waves (points 1 and 2 in Fig. 1 a). The second critical factor which should be included into consideration is the change of the longitudinal momentum of electrons. This effect is not significant for a steady-state generation regime and, as a rule, is ignored in the gyrotron theory. However, in the process of formation of giant ultrashort pulses with a very steep profile strong transverse magnetic fields are initiated even near the cutoff frequency, which, in turn, leads to transformation of the translational energy of electrons to the energy of their orbital rotation and then in the energy of an electromagnetic pulse. Correspondingly, the generalized system of equations has the following form:

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Theory of non-stationary processes in gyrotrons with low Q resonators

Cited by 175 publications

References 5 publications

Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

Генерация Ультракоротких Импульсов Субтерагерцевого И Терагерцевого Диапазонов На Основе Эффекта Циклотронного Сверхизлучения

Generation of rogue waves in gyrotrons with high excess over the threshold

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