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- Galin, Mikhail A., et al.
(författare)
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Synchronization of Large Josephson-Junction Arrays by Traveling Electromagnetic Waves
- 2018
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Ingår i: Physical Review Applied. - 2331-7019. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Mutual synchronization of many Josephson junctions is required for superradiant enhancement of the emission power. However, the larger the junction array is, the more difficult is the synchronization, especially when the array size becomes much larger than the emitted wavelength. Here, we study experimentally Josephson emission from such larger-than-the-wavelength Nb/NbSi/Nb junction arrays. For one of the arrays we observe a clear superradiant enhancement of emission above a threshold number of active junctions. The arrays exhibit strong geometrical resonances, seen as steps in current-voltage characteristics. However, radiation patterns of the arrays have forward-backward asymmetry, which is inconsistent with the solely geometrical resonance (standing-wave) mechanism of synchronization. We argue that the asymmetry provides evidence for an alternative mechanism of synchronization mediated by unidirectional traveling-wave propagation along the array (such as a surface plasmon). In this case, emission occurs predominantly in the direction of propagation of the traveling wave. Our conclusions are supported by numerical modeling of Josephson traveling-wave antenna. We argue that such a nonresonant mechanism of synchronization opens a possibility for phase locking of very large arrays of oscillators.
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- Semenov, V. E., et al.
(författare)
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Multipactor breakdown in waveguide irises
- 2009
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Ingår i: 2009 IEEE International Vacuum Electronics Conference, IVEC 2009; Rome; Italy; 28 April 2009 through 30 April 2009. - 9781424434992 ; , s. 321-322
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Konferensbidrag (refereegranskat)abstract
- A detailed analysis is made in order to establish the multipactor breakdown threshold in wave guide irises. The analysis involves an analytical investigation based on the conformal mapping technique and also extensive numerical simulations. Comparison with recent experimental results shows good agreement. The main goal of the work is to obtain multipactor charts for the iris, i.e. the breakdown voltage as a function of the frequency - gap product, for different height to width ratios of the iris.
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- Semenov, V., et al.
(författare)
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Study of multipactor in waveguide irises
- 2008
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Ingår i: MULCOPIM08, 23-26 September 2008, Valencia, Spain, European Space Agency, Nordwijk, The Netherlands, available on CD. ; , s. paper MP-3-3-
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Konferensbidrag (refereegranskat)
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