Influence of background plasma on electromagnetic properties of "Cold" gyrotron cavity

Zaginaylov, G.I.; Shcherbinin, Vitalii I.; Schuenemann, K.; Thumm, M.

doi:10.1109/tps.2006.875760

Cited by 32 publications

(13 citation statements)

References 11 publications

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“…Plasma induced effects are higher for those TE modes whose frequencies lie closer to the cyclotron frequency H of plasma electrons. Such a conclusion agrees with results in [5,10,11]. Besides, at fixed max p plasma influence on waveguide modes weakens with decreasing averaged plasma density p0 and vanishes in the limiting case p0 0.…”

Section: Coincident Frequncies Of Te and Tm Waves In Gyrotron Casupporting

confidence: 91%

“…When the core region is plasma-filled, this impedance is found from (11), where B 1 should be set equal to zero. For the core region in the form of smooth metallic rod the quantity Z 1 serves as the relative surface impedance of the rod along z axis and is a function of metal conductivity.…”

Section: B Cutoff Frequencies Of Tm Wavesmentioning

confidence: 99%

“…2 shows the influence of a non-uniform plasma on the cutoff frequencies of the operating TE 28,8 and neighboring TM 28,7 modes of 140 GHz, 1 MW CW gyrotron. As seen, plasma causes frequency up-shift for TM mode [5] and frequency down-shift for TE mode [10,11]. When plasma is non-uniform, its influence is mostly determined by the maximum value max p of the plasma density.…”

Section: Coincident Frequncies Of Te and Tm Waves In Gyrotron Camentioning

confidence: 99%

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Cutoff frequencies of a waveguide filled with radially non-uniform magnetized plasma: an efficient computing method

Shcherbinin

Zaginaylov

2014

2014 International Conference on Mathematical Methods in Electromagnetic Theory

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An efficient computing method for cutoff frequencies of radially non-uniform plasma-filled waveguide in applied magnetic field is given. The plasma-filled waveguide is approximated by a multilayer structure and the computation is performed by using the recurrence relations between fields in different layers. The dispersion equations for TE and TM modes are obtained in the form independent of number of plasma layers. The equations are valid both for circular and coaxial plasma-filled waveguides with impedance boundaries and are examined numerically for some plasma density profiles.

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Section: Coincident Frequncies Of Te and Tm Waves In Gyrotron Casupporting

confidence: 91%

Section: B Cutoff Frequencies Of Tm Wavesmentioning

confidence: 99%

Section: Coincident Frequncies Of Te and Tm Waves In Gyrotron Camentioning

confidence: 99%

See 1 more Smart Citation

Cutoff frequencies of a waveguide filled with radially non-uniform magnetized plasma: an efficient computing method

Shcherbinin

Zaginaylov

2014

2014 International Conference on Mathematical Methods in Electromagnetic Theory

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“…To keep the 10-kHz resolution of the locked LO, the sweep time of the SA (Agilent E4404B) was set to over 1 ms, and the resolution bandwidth is fixed at 10 kHz. For the long-pulse gyrotrons, a frequency downshift with longer time constant (> 1 s) is a common feature [16]- [18], but the physical mechanism of the slow-frequency downshift is still not completely understood, as mentioned in [19] and [20]. Possible explanations for the frequency downshift in this system are the following: 1) thermal expansion of the resonant cavity due to ohmic heating of the cavity walls; 2) neutralization of dc space charge fields of electron beam by impact ionization; and 3) resonance frequency modification of the cavity by the background plasma.…”

Section: Experimental Setupsmentioning

confidence: 99%

Spectral Characteristics of a 140-GHz Long-Pulsed Gyrotron

Han

Joo

et al. 2007

IEEE Trans. Plasma Sci.

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Gyrotrons operating in the millimeter and submillimeter wavelength ranges are the promising sources for applications that are requiring good spectral characteristics and a wide range of output power. We report the precise measurement results of gyrotron spectra. Experiments were conducted using a 140-GHz long-pulse gyrotron that is developed for the dynamic nuclear polarization/nuclearmagnetic-resonance spectroscopy at the Massachusetts Institute of Technology. Transient downshift of the frequency by 12 MHz with a time constant of 3 s was observed. After reaching equilibrium, the frequency was maintained within 1 ppm for over 20 s. The coefficient of the frequency change with cavity temperature was −2.0 MHz/K, which shows that fine tuning of the gyrotron frequency is plausible by cavity-temperature control. Frequency pulling by the beam current was observed, but e-mail: saiph@mit.edu.. it was shown to be masked by the downward shift of the gyrotron frequency with temperature. The linewidth was measured to be much less than 1 MHz at 60 dB relative to the carrier power [in decibels relative to carrier (dBc)] and 4.3 MHz at 75 dBc, which is the largest dynamic range to date for the measurement of gyrotron linewidth to our knowledge. NIH Public Access

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“…As is well known, plasma filling has a variety of advantages in increasing the space charge limited current, overall energy conversion efficiency, and radiation bandwidth dramatically [1][2][3] and it has been widely used in many plasma microwave radiation sources, such as traveling-wave tubes (TWT) [4], backward-wave oscillators (BWO) [5], klystrons [6], and gyrotrons [7]. Compared with the vacuum electronic devices, the EM dispersion characteristic and beam-wave energy transfer mechanism will become more complex [8].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Waves Dispersion and Interaction of an Annular Beam-Ion Channel System in Plasma Waveguide

Jixiong

Wang

Liu

2017

Advances in Mathematical Physics

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A linear theory for the electromagnetic properties and interactions of an annular beam-ion channel system in plasma waveguide is presented. The dispersion relations for two families of propagating modes, including the electrostatic and transverse magnetic modes, are derived. The dependencies of the dispersion behavior and interaction for different wave modes on the thickness of the annular beam and betatron oscillation frequency are studied in detail by numerical calculations. The results show that the inner and outer radii of the beam have different influences on propagation properties of the electrostatic and electromagnetic modes with different betatron oscillation parameters. In the weak ion channel situation, the two types of electrostatic waves, that is, space charge and betatron modes, have no interaction with the transverse magnetic modes. However, in the strong ion channel situation, the transverse magnetic modes will have two branches and a low frequency mode emerged as the new branch. In this case, compared with the solid beam case, the betatron modes not only can interact with the high frequency branch at small wavenumber but also can interact with the low frequency branch at large wavenumber.

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Influence of background plasma on electromagnetic properties of "Cold" gyrotron cavity

Cited by 32 publications

References 11 publications

Cutoff frequencies of a waveguide filled with radially non-uniform magnetized plasma: an efficient computing method

Cutoff frequencies of a waveguide filled with radially non-uniform magnetized plasma: an efficient computing method

Spectral Characteristics of a 140-GHz Long-Pulsed Gyrotron

Electromagnetic Waves Dispersion and Interaction of an Annular Beam-Ion Channel System in Plasma Waveguide

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