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- Tardocchi, M., et al.
(författare)
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Modeling of neutron emission spectroscopy in JET discharges with fast tritons from (T)D ion cyclotron heating
- 2006
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 77:12
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of fast ion populations is one of the diagnostic capabilities provided by neutron emission spectroscopy (NES). NES measurements were carried out during JET trace tritium campaign with the magnetic proton recoil neutron spectrometer. A favorable plasma scenario is (T)D where the resulting 14 MeV neutron yield is dominated by suprathermal emission from energetic tritons accelerated by radio frequency at their fundamental cyclotron frequency. Information on the triton distribution function has been derived from NES data with a simple model based on two components referred to as bulk (B) and high energy (HE). The HE component is based on strongly anisotropic tritium distribution that can be used for routine best-fit analysis to provide tail temperature values (T-HE). This article addresses to what extent the T-HE values are model dependent by comparing the model above with a two-temperature (bi-) Maxwellian model featuring parallel and perpendicular temperatures. The bi-Maxwellian model is strongly anisotropic and frequently used for radio frequency theory.
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| 4. |
- Hellesen, Carl, 1980-, et al.
(författare)
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Measurements of fast ions and their interactions with MHD activity using neutron emission spectroscopy
- 2010
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 50:8, s. 084006-
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Tidskriftsartikel (refereegranskat)abstract
- Ion cyclotron radio frequency (ICRF) heating can produce fast ion populations with energies reaching up to several megaelectronvolts. Here, we present unique measurements of fast ion distributions from an experiment with 3rd harmonic ICRF heating on deuterium beams using neutron emission spectroscopy (NES). From the experiment, very high DD neutron rates were observed, using only modest external heating powers. This was attributed to acceleration of deuterium beam ions to energies up to about 2-3 MeV, where the DD reactivity is on a par with that of the DT reaction. The high neutron rates allowed for observations of changes in the fast deuterium energy distribution on a time scale of 50 ms. Clear correlations were seen between fast deuterium ions in different energy ranges and magnetohydrodynamic activities, such as monster sawteeth and toroidal Alfven eigen modes (TAE). Specifically, NES data showed that the number of deuterons in the region between 1 and 1.5 MeV were decaying significantly during strong TAE activity, while ions with lower energies around 500 keV were not affected. This was attributed to resonances with the TAE modes.
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| 5. |
- Hellesen, Carl, 1980-, et al.
(författare)
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Neutron emission generated by fast deuterons accelerated with ion cyclotron heating at JET
- 2010
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 50:2
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, the neutron emission from JET plasmas heated with combined deuterium neutral beam injection and third harmonic ion cyclotron radio frequency heating have been studied with neutron emission spectroscopy (NES). Very high DD neutron rates were observed with only modest external heating powers, which was attributed to acceleration of deuterium beam ions to energies of about 2-3 MeV, where the DD reactivity is on a par of that of the DT reaction. Fast deuterium energy distributions were derived from analysis of NES data and confirm acceleration of deuterium beam ions up to energies around 3 MeV, in agreement with theoretical predictions. The high neutron rates allowed for observations of changes in the fast deuterium populations on a time scale of 50 ms. Correlations were seen between fast deuterium ions at different energies and magnetohydrodynamic activities, such as monster sawtooth crashes and toroidal Alfven eigenmodes.
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| 9. |
- Peters, Gregory, 1970, et al.
(författare)
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A Swedish comment on ‘review: the availability of life-cycle studies in Sweden’
- 2019
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Ingår i: International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 1614-7502 .- 0948-3349. ; 24:10, s. 1758-1759
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The article entitled ‘Review: the availability of life-cycle studies in Sweden’ by Croft and colleagues (January 2019, volume 24, issue 1, pages 6–11) has puzzled many researchers in Sweden. The stated purpose of the article is to review the availability of water and carbon footprinting studies and life-cycle assessment (LCA) studies in Sweden. Despite its title and purpose suggesting otherwise, the article appears to be about the accessibility of life-cycle case studies from Sweden in South Africa. It is problematic that the article claims to be a review in the title and text, but is presented by the journal as a commentary. We believe that the article’s method is unclear and that its title and results are misleading. The authors of the article found only 12 academic papers, 10 academic theses, 8 company reports, and 1 presentation. This result significantly underestimates the actual production and availability of Swedish LCA case studies.
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