2013/01/31 by A. Mollén, I. Pusztai, T. Fülöp +1 · 17 citations
Engineering · Physics and Astronomy · #Electron #Electron density #Impurity #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research #Mode (computer interface) #Momentum (technical analysis) #Particle accelerators and beam dynamics #Plasma #Turbulence #physics.plasm-ph
paper · pdf · doi:10.1063/1.4796196
published in Physics of Plasmas 20(3), 032310 (American Institute of Physics) · 30 pages, 10 figures
openalex publication_date 2013/03/01 · arxiv created 2013/04/03 · arxiv updated 2013/04/04 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Trapped electron mode turbulence is studied by gyrokinetic simulations with the GYRO code and an analytical model including the effect of a poloidally varying electrostatic potential. Its impact on radial transport of high-Z trace impurities close to the core is thoroughly investigated, and the dependence of the zero-flux impurity density gradient (peaking factor) on local plasma parameters is presented. Parameters such as ion-to-electron temperature ratio, electron temperature gradient, and main species density gradient mainly affect the impurity peaking through their impact on mode characteristics. The poloidal asymmetry, the safety factor, and magnetic shear have the strongest effect on impurity peaking, and it is shown that under certain scenarios where trapped electron modes are dominant, core accumulation of high-Z impurities can be avoided. We demonstrate that accounting for the momentum conservation property of the impurity-impurity collision operator can be important for an accurate evaluation of the impurity peaking factor.