| 1. |
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| 2. |
- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 3. |
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| 4. |
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| 5. |
- Eriksson, Frida, 1986, et al.
(författare)
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Interpretative and predictive modelling of Joint European Torus collisionality scans
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : Institute of Physics Publishing (IOPP). - 0741-3335 .- 1361-6587. ; 61:11
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Tidskriftsartikel (refereegranskat)abstract
- Transport modelling of Joint European Torus (JET) dimensionless collisionality scaling experiments in various operational scenarios is presented. Interpretative simulations at a fixed radial position are combined with predictive JETTO simulations of temperatures and densities, using the TGLF transport model. The model includes electromagnetic effects and collisions as well as (E)over-right-arrow x (b)over-right-arrow shear in Miller geometry. Focus is on particle transport and the role of the neutral beam injection (NBI) particle source for the density peaking. The experimental 3-point collisionality scans include L-mode, and H-mode (D and H and higher beta D plasma) plasmas in a total of 12 discharges. Experimental results presented in (Tala et al 2017 44th EPS Conf.) indicate that for the H-mode scans, the NBI particle source plays an important role for the density peaking, whereas for the L-mode scan, the influence of the particle source is small. In general, both the interpretative and predictive transport simulations support the experimental conclusions on the role of the NBI particle source for the 12 JET discharges.
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| 6. |
- Fransson, Emil, 1986, et al.
(författare)
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Comparing particle transport in JET and DIII-D plasmas: gyrokinetic and gyrofluid modelling
- 2021
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 61:1
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Tidskriftsartikel (refereegranskat)abstract
- Transport modelling, for two dimensionless collisionality scaling experiments at the Joint European Torus (JET) and DIII-D with three discharges each, is presented. Experimental data from JET (Tala et al 2019 Nucl. Fusion 59 126030) and DIII-D (Mordijck et al 2020 Nucl. Fusion 60 066019) show a dissimilar dependence in the density peaking from the source and turbulent transport. The discharges from the JET collisionality scan show that the source is dominant for the density peaking, which is contrary to DIII-D where the transport is the main cause for the peaking. In this article, the different dependency on the source is studied by investigating the zero flux density gradient (peaking factor) at radial position rho(t) = 0.6 and by calculating the averaged perturbed diffusion and pinch between rho(t) = 0.5 and rho(t) = 0.8. Results show that the difference of the normalized temperature gradients have the largest and considerable impact on the peaking factor. The calculated diffusion and pinch showed good match with the experimental measured perturbed values. The calculated ratio of the particle balance pinch and diffusion explained the difference in peaking from turbulent transport, a high ratio for DIII-D yielding high peaking and a low ratio for JET yielding low peaking. However the particle balance diffusion, which suppresses the peaking from the source, was high for DIII-D and low for JET. Thusly, explaining the particle source much larger impact on the peaking at JET.
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| 7. |
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| 8. |
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| 9. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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| 10. |
- Eriksson, Frida, 1986, et al.
(författare)
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Impact of fast ions on density peaking in JET : fluid and gyrokinetic modeling
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : Institute of Physics Publishing (IOPP). - 0741-3335 .- 1361-6587. ; 61:7
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Tidskriftsartikel (refereegranskat)abstract
- The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position rho(t) = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.
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| 11. |
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| 12. |
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| 13. |
- Krasilnikov, A., et al.
(författare)
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Evidence of 9 Be + p nuclear reactions during 2ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:2
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Tidskriftsartikel (refereegranskat)abstract
- The intensity of 9Be + p nuclear fusion reactions was experimentally studied during second harmonic (2ω CH) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H+ ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9Be + p interaction, were observed with fast ion loss detectors, γ-ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9Be(p, d)2α and 9Be(p, α)6Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.
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| 14. |
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| 15. |
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| 16. |
- Tala, T., et al.
(författare)
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Density peaking in JET-determined by fuelling or transport?
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:12
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Tidskriftsartikel (refereegranskat)abstract
- Core density profile peaking and electron particle transport have been extensively studied by performing several dimensionless collisionality (upsilon*) scans with other matched dimensionless profiles in various plasma operation scenarios on the Joint European Torus (JET). This is the first time when electron particle transport coefficients in the H-mode have been measured on JET with high resolution diagnostics, and therefore we are in a position to distinguish between the neutral beam injection (NBI) source and inward electron particle pinch in contributing to core density peaking. The NBI particle source is found to contribute typically 50%-60% to the electron density peaking in JET H-mode plasmas where T-e/T-i similar to 1 or smaller and at upsilon* = 0.1-0.5 (averaged between r/a = 0.3-0.8), and being independent of upsilon* within that range. In these H-mode plasmas, the electron particle transport coefficients, D-e and v(e), are small, thus giving rise to the large influence of NBI fueling with respect to transport effect on peaking. In L-mode plasma conditions, the role of the NBI source is small, typically 10%-20%, and the electron particle transport coefficients are large. These dimensionless upsilon* scans give the best possible data for model validation. TGLF simulations are in good agreement with the experimental results with respect to the role of NBI particle source versus inward pinch in affecting density peaking, both for the H-mode and L-mode upsilon* scans. It predicts, similarly to experimental results, that typically about half of the peaking originates from the NBI fuelling in the H-mode and 10%-20% in the L-mode. GENE simulation results also support the key role of NBI fuelling in causing a peaked density profile in JET H-mode plasma (T-e/T-i similar to 1 and upsilon* = 0.1-0.5) and, in fact, give an even higher weight on NBI fuelling than that experimentally observed or predicted by TGLF. For the non-fuelled H-mode plasma at higher T-e/T-i = 1.5 and lower beta(N) and upsilon*, both TGLF and GENE predict peaked density profiles, therefore agreeing well with experimental steady-state density peaking. Overall, the various modelling results give a fairly good confidence in using TGLF and GENE in predicting density peaking in quite a wide range of plasma conditions in JET.
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| 17. |
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- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:9
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Tidskriftsartikel (refereegranskat)
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| 18. |
-
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 19. |
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| 20. |
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| 21. |
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| 22. |
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| 23. |
- Eriksson, Daniel, et al.
(författare)
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Cytokine Autoantibody Screening in the Swedish Addison Registry Identifies Patients With Undiagnosed APS1
- 2018
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 103:1, s. 179-186
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Tidskriftsartikel (refereegranskat)abstract
- Context: Autoimmune polyendocrine syndrome type 1 (APS1) is a monogenic disorder that features autoimmune Addison disease as a major component. Although APS1 accounts for only a small fraction of all patients with Addison disease, early identification of these individuals is vital to prevent the potentially lethal complications of APS1.Objective: To determine whether available serological and genetic markers are valuable screening tools for the identification of APS1 among patients diagnosed with Addison disease.Design: We systematically screened 677 patients with Addison disease enrolled in the Swedish Addison Registry for autoantibodies against interleukin-22 and interferon-α4. Autoantibody-positive patients were investigated for clinical manifestations of APS1, additional APS1-specific autoantibodies, and DNA sequence and copy number variations of AIRE.Results: In total, 17 patients (2.5%) displayed autoantibodies against interleukin-22 and/or interferon-α4, of which nine were known APS1 cases. Four patients previously undiagnosed with APS1 fulfilled clinical, genetic, and serological criteria. Hence, we identified four patients with undiagnosed APS1 with this screening procedure.Conclusion: We propose that patients with Addison disease should be routinely screened for cytokine autoantibodies. Clinical or serological support for APS1 should warrant DNA sequencing and copy number analysis of AIRE to enable early diagnosis and prevention of lethal complications.
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
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| 29. |
- Labit, B., et al.
(författare)
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Progress in the development of the ITER baseline scenario in TCV
- 2024
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Ingår i: Plasma Physics and Controlled Fusion. - 1361-6587 .- 0741-3335. ; 66:2
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Tidskriftsartikel (refereegranskat)abstract
- Under the auspices of EUROfusion, the ITER baseline (IBL) scenario has been jointly investigated on AUG and TCV in the past years and this paper reports on the developments on TCV. Three ITER shapes, namely the JET, AUG and ITER IBL have been reproduced in TCV, illustrating that the higher the triangularity the larger the ELM perturbation and the more difficult it is to reach stationary states with q(95)< 3.6. It is found that the performance of TCV IBL is mainly limited by (neoclassical) tearing modes, in particular 2/1 modes which are triggered after a large ELM. It is demonstrated that the shorter the ELM period the larger beta(N) at the NTM onset. We show that these modes can be avoided with central X3 EC heating at relatively high q(95) and moderate beta(N). However, the lack of significant ECH at the high central densities obtained in TCV IBL scenario limits the duration of low q(95) cases to about four confinement times. During this time, density usually keeps peaking until (neoclassical) tearing modes are triggered. Nevertheless, the TCV IBL database covers the ITER target values (H-98y2 similar to 1, beta(N) similar to 1.8 at q(95 )similar to 3) and a slightly better confinement than requested for ITER is
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| 30. |
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| 31. |
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| 32. |
- Maggi, C. F., et al.
(författare)
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Isotope identity experiments in JET-ILW with H and D L-mode plasmas
- 2019
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Ingår i: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 59:7
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Tidskriftsartikel (refereegranskat)abstract
- NBI-heated L-mode plasmas have been obtained in JET with the Be/W ITER-like wall (JET-ILW) in H and D, with matched profiles of the dimensionless plasma parameters, rho*, nu*, beta and q in the plasma core confinement region and same T-i/T-e and Z(eff). The achieved isotope identity indicates that the confinement scale invariance principle is satisfied in the core confinement region of these plasmas, where the dominant instabilities are Ion Temperature Gradient (ITG) modes. The dimensionless thermal energy confinement time, Omega(i) tau(E,th), and the scaled core plasma heat diffusivity, A chi(eff)/B-T, are identical in H and D within error bars, indicating lack of isotope mass dependence of the dimensionless L-mode thermal energy confinement time in JET-ILW. Predictive flux driven simulations with JETTO-TGLF of the H and D identity pair is in very good agreement with experiment for both isotopes: the stiff core heat transport, typical of JET-ILW NBI heated L-modes, overcomes the local gyro-Bohm scaling of gradient-driven TGLF, explaining the lack of isotope mass dependence in the confinement region of these plasmas. The effect of E x B shearing on the predicted heat and particle transport channels is found to be negligible for these low beta and low momentum input plasmas.
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| 33. |
- Mordijck, S., et al.
(författare)
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Collisionality driven turbulent particle transport changes in DIII-D H-mode plasmas
- 2020
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 60:6
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Tidskriftsartikel (refereegranskat)abstract
- The results of the experimental dimensionless scan in this paper confirm that there is an increase in density peaking towards lower collisionality and that this can be partly linked to a shift in the turbulence regime from ITG towards TEM. However at the lowest collisionality, the changes in turbulence and transport are much more pronounced than expected from direct collisionality effect on the turbulence. In this paper, the collisionality, ν ∗ is varied by a factor 5, while keeping ρ ∗, q, β, M, fixed. Additionally, a 3 Hz gas puff modulation is applied to modulate the electron density profile and extract the perturbed transport coefficients using two diagnostics. The transport analysis shows that the increase in density peaking at low ν ∗ is linked to an increase in the inward particle pinch and not an increase in core fueling. These observations are not only in agreement with prior modeling scans of how turbulence changes as a function of collisionality and its impact upon the particle fluxes, but also with the multi-machine database (Fable E. et al 2010 Plasma Phys. Control. Fusion 52 015007) (Angioni C. et al 2003 Phys. Rev. Lett. 90 205003). The changes in turbulence across the collisionality scan were captured at large scale by the BES and at smaller scale by the DBS. A comparison with gradient-driven GENE simulations showed similar trends at both scales. Moreover, the changes observed in overall transport are in agreement with gradient-driven TGLF particle flux simulations. This indicates that TGLF/GENE when given the gradients as input, are able to reproduce the experimentally observed turbulence changes.
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| 34. |
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| 35. |
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| 36. |
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| 37. |
- Reimerdes, H., et al.
(författare)
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Overview of the TCV tokamak experimental programme
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with 'small' (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
- Eriksson, Daniel, et al.
(författare)
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Common genetic variation in the autoimmune regulator (AIRE) locus is associated with autoimmune Addison’s disease in Sweden
- 2018
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune Addison's disease (AAD) is the predominating cause of primary adrenal failure. Despite its high heritability, the rarity of disease has long made candidate-gene studies the only feasible methodology for genetic studies. Here we conducted a comprehensive reinvestigation of suggested AAD risk loci and more than 1800 candidate genes with associated regulatory elements in 479 patients with AAD and 2394 controls. Our analysis enabled us to replicate many risk variants, but several other previously suggested risk variants failed confirmation. By exploring the full set of 1800 candidate genes, we further identified common variation in the autoimmune regulator (AIRE) as a novel risk locus associated to sporadic AAD in our study. Our findings not only confirm that multiple loci are associated with disease risk, but also show to what extent the multiple risk loci jointly associate to AAD. In total, risk loci discovered to date only explain about 7% of variance in liability to AAD in our study population.
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| 42. |
- Eriksson, Frida, 1986, et al.
(författare)
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Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating
- 2017
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Ingår i: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2481 .- 1745-2473. ; 13:10, s. 973-978
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Tidskriftsartikel (refereegranskat)abstract
- We describe a new technique for the effcient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed 'three-ion' scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate effcient acceleration of 3He ions to high energies in dedicated hydrogen-deuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast 3He ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, 3He-rich solar flares.
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| 43. |
- Eriksson, Frida, 1986
(författare)
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Fast ions and turbulent particle transport in tokamaks
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The presence of highly energetic (fast) ions, be it fusion born alpha particles or ions accelerated by auxiliary heating schemes, can affect the heating and transport of all particles in the plasma through two main mechanisms. First, fast ions may excite fast ion driven instabilities. One such example is the toroidal Alfvén eigenmode (TAE) that can be excited by super Alfvénic ions as they slow down due to friction-like collisions with the background plasma and eventually hit the wave-particle resonances. In addition, the fast ions may influence the turbulent transport, driven by temperature and density gradients in the background plasma. The turbulent particle transport, together with particle sources, determines the peaking of the density profile in fusion devices which in turn affect the fusion power generated. In this thesis we employ a simple one-dimensional electrostatic ``bump-on-tail'' model to qualitatively describe fast ion driven TAEs whose signals exhibit frequency sweeping. The frequency sweeping is tied to the formation and evolution of phase space structures known as holes and clumps in the non-thermal fast particle distribution. We have also made realistic simulations of particle transport driven by Ion Temperature Gradient (ITG) modes in JET plasmas heated by neutral beam injection (NBI). We study the turbulent transport using fluid, gyro-fluid and gyrokinetic simulations. Focus is on particle transport and the effect of the NBI generated fast ions on the density peaking and, finally, the influence of the NBI particle source on the density peaking.
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| 44. |
- Eriksson, Frida, 1986, et al.
(författare)
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Kinetic theory of phase space plateaux
- 2015
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Ingår i: 42nd European Physical Society Conference on Plasma Physics, EPS 2015.
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Konferensbidrag (refereegranskat)
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| 45. |
- Eriksson, Frida, 1986, et al.
(författare)
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Kinetic theory of phase space plateaux in a non-thermal energetic particle distribution
- 2015
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1089-7674 .- 1070-664X. ; 22:9, s. art.no. 092126-
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Tidskriftsartikel (refereegranskat)abstract
- The transformation of kinetically unstable plasma eigenmodes into hole-clump pairs with temporally evolving carrier frequencies was recently attributed to the emergence of an intermediate stage in the mode evolution cycle, that of an unmodulated plateau in the phase space distribution of fast particles. The role of the plateau as the hole-clump breeding ground is further substantiated in this article via consideration of its linear and nonlinear stability in the presence of fast particle collisions and sources, which are known to affect the production rates and subsequent frequency sweeping of holes and clumps. In particular, collisional relaxation, as mediated by e.g. velocity space diffusion or even simple Krook-type collisions, is found to inhibit hole-clump generation and detachment from the plateau, as it should. On the other hand, slowing down of the fast particles turns out to have an asymmetrically destabilizing/stabilizing effect, which explains the well-known result that collisional drag enhances holes and their sweeping rates but suppresses clumps. It is further demonstrated that relaxation of the plateau edge gradients has only a minor quantitative effect and does not change the plateau stability qualitatively, unless the edge region extends far into the plateau shelf and the corresponding Landau pole needs to be taken into account.
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| 46. |
- Eriksson, Frida, 1986
(författare)
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Nonlinear dynamics of frequency sweeping energetic particle modes in tokamaks
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a burning plasma, such as the next generation tokamak experiment ITER, significant numbers of highly energetic particles will be produced via nuclear reactions. The presence of energetic particles, be it fusion born alpha particles or ions accelerated by auxiliary heating schemes, may excite kinetic instabilities and thereby affect the heating and transport of all particles in the plasma. Of particular interest is the toroidal Alfvén eigenmode (TAE), a cavity mode that can be excited by super Alfvénic ions as they slow down due to friction-like collisions with the background plasma and eventually hit the wave-particle resonances. Such modes have attracted much attention during almost 30 years, since their detection provides diagnostic opportunities to probe the plasma core. However, their presence and long-term behavior are still far from understood. They may have detrimental effects on the plasma confinement and heating, but can potentially also be utilized as a collisionless way to channel power from the fast ions to the bulk plasma.In this thesis we employ linear and nonlinear analysis to study fast particle driven TAEs whose signals exhibit frequency sweeping. Their existence is tied to the formation and evolution of phase space structures known as holes and clumps in the non-thermal fast particle distribution. A one-dimensional ``bump-on-tail'' model is employed and used to investigate the stability of a phase space plateau that emerges early in the mode evolution cycle. Fast particle collisions and sources are included in the analysis in order to substantiate the role of the plateau as a hole/clump breeding ground from which the frequency sweeping initiates. Furthermore, the ideas of phase-locking of fast ions orbits in the wave-particle resonances is used to calculate the radial motion of already established hole/clump modes during the frequency sweeping for the ideal cases of deeply trapped and well passing particles, and it is proposed that the intensity of the sweeping signals correlates with the fast ion environment through which the hole/clump moves.
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