Impurity transport in ITG and TE mode dominated turbulence

TL;DR

This paper investigates impurity transport in Deuterium tokamak plasmas driven by ITG and TE modes, focusing on diffusivity, convective velocity, and impurity peaking factors using fluid and gyrokinetic models.

Contribution

It introduces a detailed analysis of impurity transport mechanisms in ITG and TE mode turbulence, calculating key transport coefficients and the impurity peaking factor.

Findings

Impurity peaking factor indicates inward or outward impurity pinch.

Transport coefficients vary with turbulence type and plasma conditions.

Results help predict impurity behavior in tokamak operations.

Abstract

In the present study, turbulent impurity transport in Deuterium tokamak plasmas, driven by Ion Temperature Gradient (ITG) and Trapped Electron (TE) modes, has been investigated using fluid and gyrokinetic models. The impurity diffusivity ($D_Z$) and convective velocity ($V_Z$) are calculated, and from these the zero-flux peaking factor ($PF_0$) is derived. This quantity expresses the impurity density gradient at which the convective and diffusive transport of impurities are exactly balanced. The sign of $PF_0$ is of special interest, as it determines whether the impurities are subject to an inward ($PF_0 > 0$) or outward ($PF_0 < 0$) pinch.