| 1. |
- Dieckmann, Mark Eric, 1969-, et al.
(författare)
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Particle-in-cell simulation of a fast nonrelativistic oblique shock: Extreme electron acceleration and magnetic field amplification
- 2010
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Ingår i: EUROPEAN CONFERENCE ABSTRACTS ECA. - : European Physical Society. - 2914771622 ; , s. P2.402-
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Konferensbidrag (refereegranskat)abstract
- Plasma processes close to astrophysical shocks result in the amplification of magnetic fields and in the acceleration of electrons.We examine with PIC simulations the magnetic field amplification by the collision of two plasma clouds at a speed 0.5c, each consisting of electrons and ions. A quasi-parallel guiding magnetic field, a cloud density ratio of 10 and a plasma temperature of 25 keV are considered.We demonstrate that the magnetic energy density reaches that of the ions and that electrons are accelerated to highly relativistic speeds.
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| 2. |
- 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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| 3. |
- Pusztai, Istvan, 1983, et al.
(författare)
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Neoclassical Plateau Regime Transport in a Tokamak Pedestal
- 2010
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Ingår i: Europhysics Conference Abstracts. - 2914771622 ; 34A, s. P1.1082-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In subsonic tokamak pedestals the radial scale of plasma profiles can be comparable to the ion poloidal Larmor radius thereby making the radial electrostatic field so strong that the E×B drift has to be retained in the ion kinetic equation in the same order as the parallel streaming when B_pol
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| 4. |
- 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: Proceedings of EPS 2010, Europhysics Conference Abstracts. - 2914771622 ; 34A
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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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| 5. |
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