| 1. |
- Arrowsmith, C. D., et al.
(author)
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Laboratory realization of relativistic pair-plasma beams
- 2024
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Journal article (peer-reviewed)abstract
- Relativistic electron-positron plasmas are ubiquitous in extreme astrophysical environments such as black-hole and neutron-star magnetospheres, where accretion-powered jets and pulsar winds are expected to be enriched with electron-positron pairs. Their role in the dynamics of such environments is in many cases believed to be fundamental, but their behavior differs significantly from typical electron-ion plasmas due to the matter-antimatter symmetry of the charged components. So far, our experimental inability to produce large yields of positrons in quasi-neutral beams has restricted the understanding of electron-positron pair plasmas to simple numerical and analytical studies, which are rather limited. We present the first experimental results confirming the generation of high-density, quasi-neutral, relativistic electron-positron pair beams using the 440 GeV/c beam at CERN’s Super Proton Synchrotron (SPS) accelerator. Monte Carlo simulations agree well with the experimental data and show that the characteristic scales necessary for collective plasma behavior, such as the Debye length and the collisionless skin depth, are exceeded by the measured size of the produced pair beams. Our work opens up the possibility of directly probing the microphysics of pair plasmas beyond quasi-linear evolution into regimes that are challenging to simulate or measure via astronomical observations.
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| 2. |
- Arrowsmith, C. D., et al.
(author)
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Generating ultradense pair beams using 400 GeV/c protons
- 2021
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In: Physical Review Research. - : AMER PHYSICAL SOC. - 2643-1564. ; 3:2
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Journal article (peer-reviewed)abstract
- An experimental scheme is presented for generating low-divergence, ultradense, relativistic, electron-positron beams using 400 GeV/c protons available at facilities such as HiRadMat and AWAKE at CERN. Preliminary Monte Carlo and particle-in-cell simulations demonstrate the possibility of generating beams containing 10(13)-10(14) electron-positron pairs at sufficiently high densities to drive collisionless beam-plasma instabilities, which are expected to play an important role in magnetic field generation and the related radiation signatures of relativistic astrophysical phenomena. The pair beams are quasineutral, with size exceeding several skin depths in all dimensions, allowing the examination of the effect of competition between transverse and longitudinal instability modes on the growth of magnetic fields. Furthermore, the presented scheme allows for the possibility of controlling the relative density of hadrons to electron-positron pairs in the beam, making it possible to explore the parameter spaces for different astrophysical environments.
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| 3. |
- Badelek, B, et al.
(author)
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The photon collider at TESLA
- 2004
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In: International Journal of Modern Physics A. - 0217-751X. ; 19:30, s. 5097-5186
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Research review (peer-reviewed)abstract
- High energy photon colliders (gammagamma,gammae) are based on e(-)e(-) linear colliders where high energy photons are produced using Compton scattering of laser light on high energy electrons just before the interaction point. This paper is a part of the Technical Design Report of the linear collider TESLA.(1) Physics program, possible parameters and some technical aspects of the photon collider at TESLA are discussed.
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| 4. |
- Mortsell, D., et al.
(author)
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Cryoballoon versus radiofrequency ablation for atrial fibrillation - a study of outcome and safety based on the ESC-EHRA AF ablation long-term registry and the Swedish catheter ablation registry
- 2018
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In: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 39, s. 52-52
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Journal article (other academic/artistic)abstract
- Background: Pulmonary vein isolation (PVI), the standard for atrial fibrillation (AF) ablation, is most commonly applied with radiofrequency (RF) energy, although cryoballoon technology (CRYO) has gained widespread use.Purpose: The aim was to compare the second generation cryoballoon and the irrigated RF energy regarding outcomes and safety.Methods: In total, 4657 patients undergoing their first AF ablation were included; 982 with CRYO and 3675 with RF energy from the Swedish catheter ablation registry and the ESC- EHRA Atrial Fibrillation Ablation Long-Term registry. Primary endpoint was repeat AF ablation. Major secondary endpoints included procedural duration, tachyarrhythmia recurrence (>30 seconds duration) and complication rate.Results: The re-ablation rate after 12 months of follow-up was significantly lower in the CRYO versus the RF group, 7.8% versus 11%, p=0.0041 (Figure 1), while freedom from arrhythmia recurrence did not differ between the groups, 70.2% versus 68.2%, p=0.44. The result was not influenced by AF type and RF lesion sets. In multiple Cox regression analysis, paroxysmal AF patients had significantly lower re-ablation risk after CRYO ablation, hazard ratio 0.56 (p=0.041). Procedural duration was significantly shorter with CRYO than RF, (mean±SD) 133.6±45.2 minutes versus 174.6±58.2 minutes, p<0.001. Complication rates did not differ; 53/982 (5.4%) versus 191/3675 (5.2%), CRYO versus RF, p=0.806.Conclusion: The cryoballoon was superior to conventional RF energy by its lower re-ablation rates and shorter procedure times, irrespective of RFablation lesion set used, and with equal safety, which has important clinical and health economic implications.
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| 5. |
- Trines, R. M. G. M., et al.
(author)
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Applications of the wave kinetic approach : from laser wakefields to drift wave turbulence
- 2009
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In: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 16:5, s. 055904-
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Journal article (peer-reviewed)abstract
- Nonlinear wave-driven processes in plasmas are normally described by either a monochromatic pump wave that couples to other monochromatic waves or as a random phase wave coupling to other random phase waves. An alternative approach involves a random or broadband pump coupling to monochromatic and/or coherent structures in the plasma. This approach can be implemented through the wave kinetic model. In this model, the incoming pump wave is described by either a bunch (for coherent waves) or a sea (for random phase waves) of quasiparticles. This approach has been applied to both photon acceleration in laser wakefields and drift wave turbulence in magnetized plasma edge configurations. Numerical simulations have been compared to experiments, varying from photon acceleration to drift mode-zonal flow turbulence, and good qualitative correspondences have been found in all cases.
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| 6. |
- Trines, R. M. G. M., et al.
(author)
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Applications of the wave kinetic approach : from laser wakefields to drift wave turbulence
- 2010
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In: Journal of Plasma Physics. - 0022-3778 .- 1469-7807. ; 76:6, s. 903-914
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Journal article (peer-reviewed)abstract
- Nonlinear wave-driven processes in plasmas are normally described by either a monochromatic pump wave that couples to other monochromatic waves, or as a random phase wave coupling to other random phase waves. An alternative approach involves a random or broadband pump coupling to monochromatic and/or coherent structures in the plasma. This approach can be implemented through the wave-kinetic model. In this model, the incoming pump wave is described by either a bunch (for coherent waves) or a sea (for random phase waves) of quasi-particles. This approach has been applied to both photon acceleration in laser wakefields and drift wave turbulence in magnetized plasma edge configurations. Numerical simulations have been compared to experiments, varying from photon acceleration to drift mode-zonal flow turbulence, and good qualitative correspondences have been found in all cases.
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