Turbulent transport of impurities and their effect on energy confinement

Abstract

By presenting linear and nonlinear gyrokinetic studies, based on a balanced neutral beam injection deuterium discharge from the DIII-D tokamak, we demonstrate that impurities alter the scaling of the transport on the charge and mass of the main species, and even more importantly, they can dramatically change the energy transport even in relatively small quantities. A poloidally varying equilibrium electrostatic potential can lead to a strong reduction or sign change of the impurity peaking factor due to the combined effect of the in-out impurity density asymmetry and the EXB drift of impurities. We present an approximate expression for the impurity peaking factor and demonstrate that impurity peaking is not significantly affected by impurity self-collisions.

arXiv commentAccepted for publication in Plasma Physics and Controlled Fusion

References in corpus (1)

• Possible mechanism responsible for observed impurity outward flow under radio frequency heating

Cited by in corpus (6)

• First principles of modelling the stabilization of microturbulence by fast ions
• Isotopic dependence of impurity transport driven by ion temperature gradient turbulence
• Impurity transport in Alcator C-Mod in the presence of poloidal density variation induced by ion cyclotron resonance heating
• Global effects on neoclassical transport in the pedestal with impurities
• Radio frequency induced and neoclassical asymmetries and their effects on turbulent impurity transport in a tokamak
• Effects of collisions on impurity transport driven by electrostatic modes