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| 2. |
- Fazendeiro, Luis, 1976, et al.
(författare)
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Gyrokinetic simulations of turbulent transport in JET-like plasmas
- 2013
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Ingår i: 40th European Physical Society Conference on Plasma Physics. ; 2, s. 1074-1077
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this work turbulent transport in JET-like plasma discharges is analyzed, with main emphasison impurity transport driven by ITG/TEM modes. Gyrokinetic (GK) simulations are performedusing the GENE code [1, 2], in both quasilinear (QL) and nonlinear (NL) mode,1 and the resultsare compared with a computationally efficient fluid model [3, 4]. Particle transport is quantifiedby locally finding density gradients (R/Ln ) that yield zero particle flux, signifying a balancebetween convective and diffusive transport.The impact of the magnetic equilibrium (circular, s − α and realistic magnetic geometry) onthe various models is discussed, as well as the effects of collisionality (in both fluid and GK)and the inclusion of a (2%) Carbon background (in GK), as per JET CFC wall conditions. Theeffect of sheared toroidal rotation was also investigated and found to be important, although notfor the particular JET discharge studied in this work.
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| 4. |
- Hoenen, Olivier, et al.
(författare)
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Designing and running turbulence transport simulations using a distributed multiscale computing approach
- 2013
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Ingår i: 40th European Physical Society Conference on Plasma Physics. ; 2, s. 1094-1097
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Multiscale simulation involving slow transport and fast turbulent timescales is one amongstthree key computational challenges for Magnetic Confinement Plasmas, as identified in thePRACE report “The Scientific Case for HPC in Europe 2012-2020”. Whereas in global gy-rokinetic simulation the main challenge is parallelization efficiency (global gyrokinetic codesscaling to a huge amount of cores), the difficulty of the mulstiscale approach rely more on easeand performance of coupling single scale models together. This coupling requires generic meth-ods which have to be efficient and portable, especially when one (or more) single scale model isexecuted remotely as it may require specific hardware, bigger HPC systems or local databasesaccess.The MAPPER project is developing a software infrastructure dedicated to the design and theexecution of such distributed multiscale applications. It relies on a coupling library (MUSCLE)and few other to control the workflow execution and perform data communication betweenthe different single scale components (“kernels”). Communication is done in a transparent waywhether the kernels run locally or on a remote HPC system.We have implemented such application by using the MAPPER infrastructure and stand alonecodes developed within the EFDA Integrated Tokamak Modelling (ITM): 1-D transport equa-tions solver, 2-D geometry given by an equilibrium code, and transport coefficients given by a3-D fluxtube code. Due to the non-intrusive approach of the coupling library and to ITM efforton generic data structures, implementation of kernels is straightforward and the whole appli-cation is modular. This contribution presents the implementation, performance and preliminaryresults obtained with such multiscale method applied on present-day Tokamak configurations.
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| 5. |
- Håkansson, Frida, 1986, et al.
(författare)
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Directivity of frequency sweeping kinetic instabilities
- 2013
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Ingår i: 40th EPS Conference on Plasma Physics, EPS 2013; Espoo; Finland; 1 July 2013 through 5 July 2013. - 9781632663108 ; 1, s. 421-424
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Konferensbidrag (refereegranskat)
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| 6. |
- Igochine, Valentin, et al.
(författare)
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Identification of the beta limit in ASDEX Upgrade
- 2013
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Ingår i: 40th EPS Conference on Plasma Physics, EPS 2013, Espoo, Finland, 1-5 July 2013. - 9781632663108 ; 2, s. 1414-1417
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Konferensbidrag (refereegranskat)abstract
- Tokamak plasma is a subject of various resistive and ideal MHD instabilities which restrict the operation space of the device. For largest fusion outcome, it is preferable to operate the tokamak close to the stability limit with maximal possible pressure characterized by the value of normalized beta, , and thus maximal fusion power . In ASDEX Upgrade, the limit for maximal achievable is typically set by the resistive instabilities (tearing modes). If these instabilities are overcome or prevented, higher values of the normalized beta can be reached limited by the onset of the ideal kink instability. The actual limit depends on several factors, including the stabilizing influence of the conducting components facing the plasma surface. At present, the wall elements are far from the plasma and the stability boundary is expected to be close to the “no wall” limit (no stabilizing wall effect). Investigation of maximum achievable βN values for the different operation scenario in ASDEX Upgrade is presented in this work. Two indicators are used to detect the stability boundary:Increase of the resonant field amplification (RFA)Onset of the ideal kink modeRecently installed internal active coils are used to probe stability of the plasma by the RFA technique. A wide range of different MHD diagnostics are used to identify the behaviour and structure of MHD modes in different discharges with high . Experimentally obtained results are compared with the results of the numerical modelling with linear MHD codes CASTOR-FLOW and MARS-K. Such comparison allows to validate the plasma model used in the codes and therefore to make numerical projection for further experimental studies.
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| 8. |
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| 9. |
- Mollén, Albert, 1985, et al.
(författare)
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Impurity peaking in tokamaks
- 2013
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Ingår i: Proceedings of 40th European Physical Society meeting on Plasma Physics. - 9781632663108 ; 2, s. 1034-1037
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Konferensbidrag (refereegranskat)
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| 13. |
- Pusztai, Istvan, 1983, et al.
(författare)
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Electron flow driven instability in finite beta plasmas
- 2013
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Ingår i: Proceedings of the 40th EPS conference on plasma Physics, Espoo, Finland, Europhysics Conference Abstracts. - 9781632663108 ; 2, s. 1098-1101
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Konferensbidrag (refereegranskat)
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