| 1. |
- Niemi, MEK, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 2. |
- Kanai, M, et al.
(författare)
-
- 2023
-
swepub:Mat__t
|
|
| 3. |
- Abel, I, et al.
(författare)
-
Overview of the JET results with the ITER-like wall
- 2013
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
-
Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
|
|
| 4. |
- Romanelli, F, et al.
(författare)
-
Overview of the JET results
- 2011
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
-
Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
|
|
| 5. |
- Monier-Garbet, P, et al.
(författare)
-
Impurity-seeded ELMy H-modes in JET, with high density and reduced heat load
- 2005
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 45:11, s. 1404-1410
-
Tidskriftsartikel (refereegranskat)abstract
- Experiments performed at JET during the past two years show that, in high triangularity H-mode plasmas with I-p = 2.5 MA, n(e)/n(Gr) approximate to 1.0, it is possible to radiate separately up to approximate to 40% of the total injected power on closed flux surfaces in the pedestal region (argon seeding) and up to approximate to 50% of the injected power in the divertor region (nitrogen seeding), while maintaining the confinement improvement factor at the value required for ITER, H98(y, 2) 1.0. The total radiated power fraction achieved in both cases (65-70%) is close to that required for ITER. However, Type I ELMS observed with impurity seeding have the same characteristics as that observed in reference pulses without seeding: decreasing plasma energy loss per ELM with increasing pedestal collisionality. One has to reach the Type III ELM regime to decrease the transient heat load to the divertor to acceptable values for ITER, although at the expense of confinement. The feasibility of an integrated scenario with Type-III ELMS, and q(95) = 2.6 to compensate for the low H factor, has been demonstrated on JET. This scenario would meet ITER requirements at 17 MA provided that the IPB98 scaling for energy content is accurate enough, and provided that a lower dilution is obtained when operating at higher absolute electron density.
|
|
| 6. |
- Swat, M. J., et al.
(författare)
-
Pharmacometrics Markup Language (PharmML) : Opening New Perspectives for Model Exchange in Drug Development
- 2015
-
Ingår i: CPT. - : American Society for Clinical Pharmacology & Therapeutics. - 2163-8306. ; 4:6, s. 316-319
-
Tidskriftsartikel (refereegranskat)abstract
- The lack of a common exchange format for mathematical models in pharmacometrics has been a long-standing problem. Such a format has the potential to increase productivity and analysis quality, simplify the handling of complex workflows, ensure reproducibility of research, and facilitate the reuse of existing model resources. Pharmacometrics Markup Language (PharmML), currently under development by the Drug Disease Model Resources (DDMoRe) consortium, is intended to become an exchange standard in pharmacometrics by providing means to encode models, trial designs, and modeling steps.
|
|
| 7. |
- De Neve, Jan-Walter, et al.
(författare)
-
Are out-of-school adolescents at higher risk of adverse health outcomes? Evidence from 9 diverse settings in sub-Saharan Africa
- 2020
-
Ingår i: Tropical Medicine & International Health. - : Wiley. - 1365-3156 .- 1360-2276. ; 25:1, s. 70-80
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: We analysed mutually comparable surveys on adolescent attitudes and behaviours from nine sites in seven sub‐Saharan African countries, to determine the relationship between school enrolment and adolescent health outcomes.Methods: Data from the Africa Research, Implementation Science, and Education Network cross‐sectional adolescent health surveys were used to examine the associations of current school enrolment, self‐reported general health and four major adolescent health domains: (i) sexual and reproductive health; (ii) nutrition and non‐communicable diseases; (iii) mental health, violence and injury; and (iv) healthcare utilisation. We used multivariable Poisson regression models to calculate relative risk ratios with 95% confidence intervals (CI), controlling for demographic and socio‐economic characteristics. We assessed heterogeneity by gender and study site.Results: Across 7829 adolescents aged 10–19, 70.5% were in school at the time of interview. In‐school adolescents were 14.3% more likely (95% CI: 6–22) to report that their life is going well; 51.2% less likely (95% CI: 45–67) to report ever having had sexual intercourse; 32.6% more likely (95% CI: 9–61) to report unmet need for health care; and 30.1% less likely (95% CI: 15–43) to report having visited a traditional healer. School enrolment was not significantly associated with malnutrition, low mood, violence or injury. Substantial heterogeneity was identified between genders for sexual and reproductive health, and in‐school adolescents were particularly less likely to report adverse health outcomes in settings with high average school enrolment.Conclusions: School enrolment is strongly associated with sexual and reproductive health and healthcare utilisation outcomes across nine sites in sub‐Saharan Africa. Keeping adolescents in school may improve key health outcomes, something that can be explored through future longitudinal, mixed‐methods, and (quasi‐)experimental studies.
|
|
| 8. |
- Giroud, C., et al.
(författare)
-
Integration of a radiative divertor for heat load control into JET high triangularity ELMy H-mode plasmas
- 2012
-
Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 52:6, s. 063022-
-
Tidskriftsartikel (refereegranskat)abstract
- Experiments on JET with a carbon-fibre composite wall have explored the reduction of steady-state power load in an ELMy H-mode scenario at high Greenwald fraction similar to 0.8, constant power and close to the L to H transition. This paper reports a systematic study of power load reduction due to the effect of fuelling in combination with seeding over a wide range of pedestal density ((4-8) x 10(19) m(-3)) with detailed documentation of divertor, pedestal and main plasma conditions, as well as a comparative study of two extrinsic impurity nitrogen and neon. It also reports the impact of steady-state power load reduction on the overall plasma behaviour, as well as possible control parameters to increase fuel purity. Conditions from attached to fully detached divertor were obtained during this study. These experiments provide reference plasmas for comparison with a future JET Be first wall and an all W divertor where the power load reduction is mandatory for operation.
|
|
| 9. |
- Mayoral, M. L., et al.
(författare)
-
Hydrogen plasmas with ICRF inverted minority and mode conversion heating regimes in the JET tokamak
- 2006
-
Ingår i: Nuclear Fusion. - 0029-5515 .- 1741-4326. ; 46:7, s. S550-S563
-
Tidskriftsartikel (refereegranskat)abstract
- During the initial operation of the International Thermonuclear Experimental Reactor (ITER), it is envisaged that activation will be minimized by using hydrogen (H) plasmas where the reference ion cyclotron resonance frequency (ICRF) heating scenarios rely on minority species such as helium (He-3) or deuterium (D). This paper firstly describes experiments dedicated to the study of He-3 heating in H plasmas with a sequence of discharges in which 5 MW of ICRF power was reliably coupled and the He-3 concentration, controlled in real-time, was varied from below 1% up to 10%. The minority heating (MH) regime was observed at low concentrations (up to 2%). Energetic tails in the He-3 ion distributions were observed with effective temperatures up to 300 keV and bulk electron temperatures up to 6 keV. At around 2%, a sudden transition was reproducibly observed to the mode conversion regime, in which the ICRF fast wave couples to short wavelength modes, leading to efficient direct electron heating and bulk electron temperatures up to 8 keV. Secondly, experiments performed to study D minority ion heating in H plasmas are presented. This MH scheme proved much more difficult since modest quantities of carbon
|
|
| 10. |
- Mayoral, M L, et al.
(författare)
-
ICRF heating for the non-activated phase of ITER : From inverted minority to mode conversion regime
- 2005
-
Ingår i: Radio Frequency Power in Plasmas. ; , s. 122-129
-
Konferensbidrag (refereegranskat)abstract
- In the initial phase of ITER H plasmas will be used in order to avoid activating the machine. The reference ICRF heating scenarios rely on minority species such as Helium (3 He) or deuterium (D). These schemes' distinctive feature comes from the presence of the fast magnetosonic wave ion-ion hybrid resonance/cut-off pair, between the antennas and the minority cyclotron layer. In order to document these unusual heating schemes, ICRF experiments were carried out recently on JET. First, the use of He-3 ions in H plasmas was investigated with a sequence of discharges in which 5 MW of ICRF power was coupled to the plasma and the 3 He concentration was varied from below 1% up to 10%. The inverted minority heating regime was observed at low concentrations (up to similar to 2%). Energetic tails in the 3 He distribution were observed with effective temperatures up to 300 keV and central electron temperatures up to 6 keV. At around 2%, a sudden transition was reproducibly observed to the mode conversion regime, in which the ICRF fast wave couples to short wavelength modes, leading to efficient direct electron heating and central electron temperature up to 8 keV. All these experiments systematically used power modulation techniques to assess the radial profiles of the wave absorption by the electrons. Secondly, experiments to study the ICRF heating of D minority ions in H were performed. This heating scheme proved much more difficult since modest quantities of C6+ impurity, which has the same Z/A ratio than die D minority ions, led us directly into the mode conversion regime. This effect preventing any absorption by D ions at minority cyclotron layer, could make die (D)H scenario not suitable for the non-active phase of ITER.
|
|
