Turbulent features near the X point of a DTT-like tokamak plasma

TL;DR

This study uses 3D electro-static fluid simulations to analyze turbulent transport near the X point in a DTT-like tokamak plasma, revealing spectral features, structure formations, and boundary effects relevant for plasma confinement.

Contribution

It provides new insights into turbulence behavior near X points in tokamaks, highlighting the influence of magnetic geometry and boundary conditions on plasma transport.

Findings

Turbulent spectral features depend on pressure gradients and diffusivity.

Small-scale structures relate to toroidal asymmetries.

Radial boundary conditions influence zonal flow excitation.

Abstract

The background magnetic geometry at the edge of a tokamak plasma has to be designed in order to mitigate the particle and energy looses essentially due to turbulent transport. The Divertor-Tokamak-Test (DTT) facility under construction at ENEA Frascati will test several magnetic configurations and mitigation strategies, that are usually based on the realization of nontrivial topologies in which one or more X points are present. In order to get a clear understanding of turbulent transport near one of such X points, we perform 3D electro-static fluid simulations of tokamak edge plasma for a DTT-like scenario. We will outline: i) the resulting turbulent spectral features and their dependence on some model parameters (the background pressure gradients and diffusivity) and on the magnetic geometry through a comparative analysis with the results of the companion paper [19], ii) the connection between small scale poloidal structures and toroidal asymmetries, iii) the formation of quiescent regions, iv)the crucial role of radial Dirichlet boundary conditions for the excitation of zonal flows that can screen the radial component of the magnetic geometry.