Turbulent impurity transport in tokamaks
Licentiatavhandling, 2013

Nuclear fusion is foreseen as one of the options for future energy production. One of the remaining scientific challenges for establishing the physics basis of future magnetic fusion reactors is to find scenarios where the impurity content in the core can be kept low. High concentration of impurities leads to dilution and radiative energy losses and is detrimental for fusion reactivity. Therefore the understanding and control of impurity transport is of critical importance for the success of fusion. Impurity transport in fusion plasmas is dominated by turbulent fluctuations. This thesis addresses the effect of poloidal asymmetries and the role of electromagnetic effects on turbulent impurity transport. Transport driven by ion temperature gradient (ITG) mode, trapped electron (TE) mode and kinetic ballooning mode (KBM) turbulence is studied through gyrokinetic modeling. It is shown that poloidal asymmetries significantly affect radial transport, and could be a contributing reason for the experimentally observed decrease of impurity core content in the presence of plasma heating through radiofrequency waves. Furthermore, we show that the value of the ratio of plasma pressure to magnetic pressure can affect the impurity peaking, which is typically found to be lower in KBM turbulence than in ITG turbulence.

gyrokinetic

tokamak

impurity

poloidal asymmetry.

turbulence

transport

fusion plasma physics

FB-salen, Fysikgården 4, Chalmers University of Technology.
Opponent: Prof. Per Helander, Max Planck Institute for Plasma Physics, Greifswald, Germany.

Författare

Albert Mollén

Chalmers, Teknisk fysik, Nukleär teknik

Impurity transport due to electromagnetic drift wave turbulence

Physics of Plasmas,; Vol. 19(2012)p. 032301-

Artikel i vetenskaplig tidskrift

Effect of poloidal asymmetries on impurity peaking in tokamaks

Physics of Plasmas,; Vol. 19(2012)p. 052307-

Artikel i vetenskaplig tidskrift

Drivkrafter

Hållbar utveckling

Styrkeområden

Energi

Fundament

Grundläggande vetenskaper

Ämneskategorier

Fusion, plasma och rymdfysik

CTH-NT - Chalmers University of Technology, Nuclear Engineering: 268

FB-salen, Fysikgården 4, Chalmers University of Technology.

Opponent: Prof. Per Helander, Max Planck Institute for Plasma Physics, Greifswald, Germany.