| 21. |
- Buyanova, M., et al.
(författare)
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Influence of secondary emission yield on the saturation of two-sided multipactor
- 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 MP5-6
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Konferensbidrag (refereegranskat)
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| 22. |
- Buyanova, M., et al.
(författare)
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Influence of secondary emission yield on the saturation properties of multipactor discharges between two parallel metal plates
- 2010
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1089-7674 .- 1070-664X. ; 17:4, s. 043504 -
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Tidskriftsartikel (refereegranskat)abstract
- A detailed numerical simulation analysis is made of the saturation stage of multipactor discharges between two infinite parallel metal plates in vacuum exposed to a rf voltage. The main physical effect causing saturation of the multipactor discharge is increased space charge, as the electron density becomes large. It is found that the properties of the saturation stage depend crucially on the value of the secondary emission yield of the metal surfaces. Below a certain threshold value, the discharge has a two-sided character, but at this threshold the discharge makes an abrupt transition into two decoupled single-sided multipactor discharges containing significantly increased electron densities. The result of the numerical simulations gives a good picture of the saturation properties of the multipactor discharge and is also supplemented by an approximate analytical investigation that highlights and explains the characteristic properties of the observed saturation behavior.
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| 23. |
- Buyanova, M., et al.
(författare)
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Multi-Phase Regimes of Multipactor Breakdown
- 2005
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Ingår i: Proc. 5th International Workshop on Multipactor, Corona and Passive Intermodulation, September 12 – 14, 2005, ESTEC, Noordwijk, The Netherlands, In: Space RF Hardware (MULCOPIM' 2005). ; , s. 135-142
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Konferensbidrag (refereegranskat)
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| 24. |
- Bäckström, Mats G., et al.
(författare)
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Can intentional electrical discharges be used for HPM protection?
- 2011
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Ingår i: 2011 IEEE International Symposium on Electromagnetic Compatibility, EMC 2011; Long Beach, CA; 14 August 2011 through 19 August 2011. - 1077-4076. ; , s. 752-757
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Konferensbidrag (refereegranskat)abstract
- The possibility to protect electronics against High Power Microwaves (HPM) using an intentional electrical discharge triggered by the HPM pulse has been investigated. The case considered is a resonant slot, located e.g. in an antenna array or in a Frequency Selective Surface (FSS). The reduction of the pulse energy transmitted through the slot is regarded to be the most important parameter of merit. Experimental and theoretical research showed that a spark in the middle of a 46.3 0.1 mm resonant slot, induced by the incident HPM-pulse, gave a reduction of the transmitted pulse energy of about 24 dB. The studies showed that the investigated approach can provide a quite good level of protection that at least reduces the requirements on additional protection components such as limiters integrated in receivers located behind the slot. In order to achieve a sufficiently strong enhancement of the electric field to initiate breakdown in wide slots one presumably has to introduce a small pointed gap in the middle of the slot. This may in turn require that a radioactive sample is located close to the gap in order to produce a sufficient number of seed electrons necessary for triggering the discharge. © 2011 IEEE.
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| 25. |
- Cattani, F., et al.
(författare)
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Co-propagating Bose-Einstein condensates and electromagnetic radiation: Emission of mutually localized structures
- 2011
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 83:1, s. 013608-
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the details of the formation of mutually guided and localized structures of co-propagating coherent electromagnetic radiation and a Bose-Einstein condensate (BEC). In the limit of zero temperature and large detuning, we have used a semiclassical model based on Maxwell equations coupled to the Schrodinger equation which includes the back action of the atoms on the radiation. Following numerically the two systems, we have found that a variety of effects can be displayed depending on the initial conditions: The formation of single-hump mutually guided structures of atoms and radiation seems to be only one of the possible outcomes of the interaction. Other effects we have observed via numerical simulations are, for instance, the creation of atom-laser solitarylike structures which are then symmetrically ejected from the initial central peak or similar symmetrical structures trapped in a bound state and thus oscillating about the central point in a way somehow reminiscent of purely nonlinear optics effect.
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| 26. |
- Cattani, F., et al.
(författare)
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Co-propagating Bose-Einstein condensates and electromagnetic radiation: formation of mutually localized structures
- 2010
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 1361-6455 .- 0953-4075. ; 43:8
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Tidskriftsartikel (refereegranskat)abstract
- A semi-classical model is derived for describing the interaction between coherent electromagnetic radiation and a Bose-Einstein condensate in the limit of zero temperature, including the back action of the atoms on the radiation. This model is used to analyse the problem of the self-consistent evolution of a laser beam and a BEC atomic beam. The mutual propagation is studied numerically and demonstrates not only the possibility of a stationary regime of mutual guiding, but also of generating a collapse-like phenomenon.
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| 27. |
- Cattani, F., et al.
(författare)
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Interacting laser and Bose-Einstein-condensate atomic beams: Mutual guiding structures
- 2010
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 81:4, s. 043623 -
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Tidskriftsartikel (refereegranskat)abstract
- A basic set of equations describing the interaction of a Bose-Einstein condensate (BEC) with a laser field is derived based on a semiclassical model and applied to the problem of mutual guiding of laser and BEC atomic beams. Within this framework we have studied stationary spatially localized solutions of the nonlinear system which describe possible laser and BEC atomic beam guiding and have shown their stability as well. It is also shown that a self-guiding effect can be realized through both single-and multiple-scaled structures of a BEC atomic and a laser beam.
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| 28. |
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| 29. |
- Cattani, F., et al.
(författare)
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Multihump soliton-like structures in interactions of lasers and Bose-Einstein condensates
- 2011
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Ingår i: Europhysics Letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 94:5, s. 53003-
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Tidskriftsartikel (refereegranskat)abstract
- An investigation is made of multihump and periodic solutions of the semiclassical coupled equations describing laser radiation copropagating with a Bose-Einstein condensate. Solutions reminiscent of optical vector solitons have been found and have been used to gain understanding of the dynamics observed in the numerical simulations, in particular to shed light on the phenomenon of jet emission from a condensate interacting with a laser.
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| 30. |
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