Nonstationary processes in an oscillator with delayed reflection from the load

Novozhilova, Yu. V.; Ryskin, Nikita M.; Usacheva, S. A.

doi:10.1134/s1063784211090167

Cited by 12 publications

(5 citation statements)

References 7 publications

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“…Recently, a new type of output quasi optical transducers converting a wave arrived from the output channel (reflection or external signal) into the operating mode has been developed at the Institute of Applied Physics, Russian Academy of Sciences [10]. One might expect these transducers to make it possible to stabilize the gyrotron radiation frequency.In this Letter, we show that the wave reflected from a load, both resonant and nonresonant, can capture and stabilize the gyrotron radiation frequency if the difference in frequencies of the reflected and freely emitted (in the absence of reflections) waves does not exceed a value on the order of |R|ω 0 /Q (Q is the dif fraction Q factor and |R| is the magnitude of the reflec tance) [5]. This value is an analog of the capture band (or locking band) width when a specified external monochromatic force is exerted on the active oscilla tor [4].…”

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confidence: 88%

“…In this Letter, we show that the wave reflected from a load, both resonant and nonresonant, can capture and stabilize the gyrotron radiation frequency if the difference in frequencies of the reflected and freely emitted (in the absence of reflections) waves does not exceed a value on the order of |R|ω 0 /Q (Q is the dif fraction Q factor and |R| is the magnitude of the reflec tance) [5]. This value is an analog of the capture band (or locking band) width when a specified external monochromatic force is exerted on the active oscilla tor [4].…”

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confidence: 88%

“…These stationary states are longitudinal modes with a single hump field structure in the cavity and different numbers of longitudinal field variations in the delay line. Some states may be unstable (at dΩ/dω r < 0) [2,4,5]. The stationary regime of gyrotron generation corresponds to one of the stable longitudinal modes.…”

Section: Stabilization Of Gyrotron Frequency By Reflection From Nonrementioning

confidence: 99%

“…The gyrotron cold frequency may vary within the width of the capture band by the reflected wave |R|ω 0 /Q [5,8]. When the gyrotron frequency is stabi lized by reflection from a nonresonant load, the opti mal phase of the reflected wave is formed automati cally, whereas, in the case of frequency stabilization by reflection from a resonant load, the reflected wave phase should be chosen specially (for example, by changing the distance to the reflector or using a phase shifter [6]).…”

Section: Stabilization Of Gyrotron Frequency By Reflection From Nonrementioning

confidence: 99%

“…In this study, we propose a method of gyrotron frequency stabilization by a wave reflected from a dis tant load. The influence of delayed reflections on the operation of active oscillators, including gyrotrons, has been investigated by many researchers (see, for example, [2][3][4][5][6][7][8]). However, specific schemes of gyrotron frequency stabilization by a reflected wave have not been discussed, because the reflected wave in a gyrotron with a conventional output quasi optical transducer returns to the operating space as a counter rotation mode, which weakly interacts with an elec tron beam [9].…”

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confidence: 99%

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Stabilization of gyrotron frequency by reflection from nonresonant and resonant loads

et al. 2015

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It is known that the gyrotron radiation frequency may be unstable because of supply voltage fluctuations [1]. At the same time, some applications, such as plasma diagnostics, high resolution spectroscopy, and (possibly in the future) formation of a complex of coherently emitting gyrotrons in large setups for con trolled fusion, call for frequency stabilized radiation sources. In this study, we propose a method of gyrotron frequency stabilization by a wave reflected from a dis tant load. The influence of delayed reflections on the operation of active oscillators, including gyrotrons, has been investigated by many researchers (see, for example, [2][3][4][5][6][7][8]). However, specific schemes of gyrotron frequency stabilization by a reflected wave have not been discussed, because the reflected wave in a gyrotron with a conventional output quasi optical transducer returns to the operating space as a counter rotation mode, which weakly interacts with an elec tron beam [9]. Recently, a new type of output quasi optical transducers converting a wave arrived from the output channel (reflection or external signal) into the operating mode has been developed at the Institute of Applied Physics, Russian Academy of Sciences [10]. One might expect these transducers to make it possible to stabilize the gyrotron radiation frequency.In this Letter, we show that the wave reflected from a load, both resonant and nonresonant, can capture and stabilize the gyrotron radiation frequency if the difference in frequencies of the reflected and freely emitted (in the absence of reflections) waves does not exceed a value on the order of |R|ω 0 /Q (Q is the dif fraction Q factor and |R| is the magnitude of the reflec tance) [5]. This value is an analog of the capture band (or locking band) width when a specified external monochromatic force is exerted on the active oscilla tor [4].The self consistent equations of gyrotron, into which the wave arrives from the output waveguide after being reflected from the load, within the approxima tion of fixed longitudinal field structure and small reflectance, can be written as [2,3,9] (1)The electric field of the operating TE mode in the interaction space can be written as E = Re(E s (r ⊥ )G(z, t)), where ω 0 is the reference frequency; the gyrotron cavity is a cylindrical segment with a mean radius r 0 close to the critical one; E s (r ⊥ ) = -i[∇ ⊥ ψ, z 0 ]/k describes the transverse structure coinciding with the transverse structure of one of the cavity modes; k = ω 0 /c; ψ = J m (kr)e -imϕ ; r and ϕ are the radial and azi muthal coordinates, respectively; a(t) = |a(t)|e iφ(t) is the slowly varying in time dimen sionless complex field amplitude; f(z) = exp(-3(zz 0 ) 2 / ) is the longitudinal field structure (it is assumed that |f(0)| = |f(2z 0 )| = |f max |/e 3 ); a τ is the field amplitude at instant t -τ; τ is the delay time; ω r is the real part of the cold cavity frequency; R = |R|e iα is the complex coefficient of reflection from the load; p = (p x + ip y ) / ( β ⊥0 m e cγ 0 ) is the dimension le...

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confidence: 88%

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confidence: 88%