| 1. |
- Nordman, Hans, 1957, et al.
(författare)
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Modelling of impurity transport experiments at the Joint European Torus
- 2010
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Ingår i: Proceedings of EPS 2010, Europhysics Conference Abstracts. - 2914771622 ; 34A
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Konferensbidrag (refereegranskat)abstract
- Impurity transport in JET is studied using interpretative analysis and predictive simulations of JET discharges. The simulations are based on transport models for Ion-Temperature-Gradient (ITG) mode and Trapped-Electron (TE) mode driven turbulence and neoclassicaltransport. The properties of the impurity transport coefficients obtained with fluid as well as quasi-linear and nonlinear gyrokinetic simulations using the code GENE are compared and discussed. In particular, the sign of the impurity convective velocity (pinch) and the scaling of the normalised impurity density peaking factor -R∇nZ/nZ with impurity charge number is investigated. Predictive simulations of temperatures (Te, Ti=TZ) and densities (ne,nZ) are performed with the JETTO/SANCO core transport code.The scaling of impurity transport with impurity charge Z is crucial for the performance and optimisation of a fusion reactor. In the present study, a set of dedicated JET impurity injection experiments are analysed. The impurities were injected by laser ablation (Ni) and gas injection (Ne, Ar) and the diffusivity DZ and convective velocity VZ were determined by matching spectroscopic data with predictive results obtained with the transport code UTC-SANCO.
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| 2. |
- Skyman, Andreas, 1982, et al.
(författare)
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Impurity transport in ITG and TE mode dominated turbulence
- 2010
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Ingår i: EPS 2010.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The transport properties of impurities is of high relevancefor the performance and optimisation of magnetic fusiondevices. For instance, impurities from plasma-facing surfaces accumulating in the core dilute the plasma and leadto unacceptable energy loss in the form of radiation.In the present study, turbulent impurity transport in tokamak plasmas, driven by Ion Temperature Gradient (ITG)and Trapped Electron (TE) modes, is investigated usingfluid and gyrokinetic models. Quasilinear (QL) results obtained from the GENE code are compared with fluidresults for ITG and TE mode dominated turbulence.Scalings of the peaking factor with impurity charge (Z) andvarious parameters are studied. Of particular interest areconditions favouring an outward convective impurity flux.
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| 3. |
- Skyman, Andreas, 1982, et al.
(författare)
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Impurity transport in ITG and TE mode dominated turbulence
- 2010
-
Ingår i: Proceedings of EPS 2010, Europhysics Conference Abstracts. - 2914771622 ; 34A
-
Konferensbidrag (refereegranskat)abstract
- The transport properties of impurities is of high relevancefor the performance and optimisation of magnetic fusion devices. For instance, if impurities from the plasmafacingsurfaces accumulate in the core, wall-impurities of relatively low density suffice to dilute the plasma and leadto unacceptable energy losses in the form of radiation.In the present study, turbulent impurity transport in Deuterium tokamak plasmas, driven by Ion TemperatureGradient (ITG) and Trapped Electron (TE) modes, hasbeen investigated using fluid and gyrokinetic models. The impurity diffusivity (DZ) and convective velocity (VZ) are calculated, and from these the zero-flux peaking factor (PF0) is derived.
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| 4. |
- Skyman, Andreas, 1982, et al.
(författare)
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Turbulent impurity transport in fusion plasmas
- 2010
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Ingår i: RUSA conference 2010.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The modern fusion device is very challenging both theoretically and numerically, much owing to turbulence driven by sharp gradients in density and temperature. However, understanding the resulting transport is crucial for the success of future fusion devices such as ITER.In this work, the turbulent transport of trace impurities in a tokamak device has been studied through quasilinear (QL) and non-linear (NL) gyrokinetic simulations using the GENE code, and with QL fluid imulations. The results are quantitative and qualitative assessments of the transport properties of several impurity species, and the dependence thereof on various plasma parameters.
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| 5. |
- Strand, Pär, 1968, et al.
(författare)
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Core transport studies in fusion devices
- 2010
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Ingår i: SNIC progress report : 2008-2009. Swedish national infrastructure for computing..
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Comprehensive first principles modelling of fusion plasmas is a numerically challenging: the complicated magnetic geometry and long range electromagnetic interactionsbetween multiple species introduce complex collective behaviour in the plasma. In addition, steep density and temperature gradients combined with an inhomogeneousmagnetic field drives instabilities, resulting in non-linear dynamics and turbulence.The turbulence in magnetically confined fusion plasmas has important and non-trivial effects on the quality of the energy confinement. These effects are hard to make a quantitative assessment of analytically. The problem investigated in this article is the transport of energy and particles, in particular impurities, in a Tokamak plasma. Impurities from the walls of the plasma vessel cause energy losses if they reach the plasma core. It is therefore important to understand the transport mechanisms to prevent impurity accumulation and minimize losses. This is an areaof research where turbulence plays a major role and is intimately associated with the performance of future fusion reactors, such as ITER.
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| 6. |
- Strand, Pär, 1968, et al.
(författare)
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Core transport studies in fusion devices
- 2010
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Ingår i: PDC 20th Anniversary and SNIC Interaction Conference 2010.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Comprehensive first principles modelling of fusion plasmascontains many numerical and theoretical challenges: a complicated magnetic geometry, long range electromagnetic interactions, collective modes, and extreme density and temperature gradients driving turbulent fluctuations, to name just a few. HPC provides the tools for tackling these challenges and is the focus of a major undertaking within the European fusion community. In this work, the turbulent transport of trace impurities in a tokamak device has been studied using quasi-linear and non-linear gyrokinetic simulations from the GENE code. The results are quantitative and qualitative assessments of the transport properties of several impurity species, and the dependence thereof on various plasma parameters.
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