Fast H isotope and impurity mixing in Ion-Temperature-Gradient turbulence

Fast H isotope and impurity mixing in Ion-Temperature-Gradient turbulence

Fast H isotope and impurity mixing in Ion-Temperature-Gradient turbulence 150 150 Mathew
UKAEA-CCFE-PR(18)10

Fast H isotope and impurity mixing in Ion-Temperature-Gradient turbulence

In Ion-Temperature-Gradient (ITG) driven turbulence, the resonance condition leads to ion particle turbulent transport coefficients significantly larger than electron particle turbulent transport coefficients. This is shown in non-linear gyrokinetic simulations and explained by an analytical quasilinear model. It is then illustrated by JETTO-QuaLiKiz integrated modelling. Large ion particle transport implies that the ion density profiles are uncorrelated to the corresponding ion source, hence peaked isotope density profiles even in the absence of core source, no accumulation of He ashes and fast impurity transport. Furthermore, the relaxation time of the individual ion profiles in a mixed system can be significantly faster than the total density profile relaxation time which is constrained by the electrons. In Trapped-Electron-Mode (TEM) turbulence, in presence of electron heating about twice the ion heating, the situation is the inverse: ion particle turbulent transport coefficients are smaller than their electron counterpart.

Collection:
Journals
Journal:
Nuclear Fusion
Publisher:
IOP