Reproducing anomalous transport coefficients from electro-static tokamak edge turbulent dynamics

TL;DR

This paper investigates turbulent transport near the tokamak X-point, showing that anomalous high transport coefficients arise naturally from nonlinear plasma dynamics, with implications for modeling and predicting plasma behavior.

Contribution

It demonstrates that anomalous transport coefficients in tokamak edge turbulence are inherent to nonlinear drift dynamics and explores their scaling with turbulent energy.

Findings

Transport is diffusive with high anomalous coefficients

Transport depends on turbulent energy spectral properties

Anomalous transport is an inherent nonlinear plasma feature

Abstract

Turbulent transport near the X-point of a large tokamak is examined using local, gradient-driven simulations that determine the saturated plasma profiles. The distribution of a representative set of particle tracers evolving within these profiles is then analyzed. The study demonstrates that the resulting transport is diffusive, characterized by a coefficient that depends on the spectral properties of the turbulent energy and attains anomalous high values under broad conditions. These findings suggest that anomalous transport is an inherent outcome of the fundamental non-linear drift dynamics of plasmas. The scaling of transport with turbulent energy is also addressed, with implications for future progress toward a mean-field framework for turbulent transport.