Particle-in-cell methods in edge plasma physics: the PICLS code

TL;DR

This paper presents the development and extension of the PICLS particle-in-cell code for edge plasma physics, enabling 3D simulations of turbulence in tokamak edge regions with validation against existing models.

Contribution

The paper introduces the extension of the PICLS code to three spatial dimensions for edge plasma turbulence simulation, including validation and comparison with other codes.

Findings

PICLS successfully extended to 3D for edge plasma turbulence.

Validation shows good agreement with existing models.

Code enables detailed study of SOL region dynamics.

Abstract

Over the past decades, multiple gyrokinetic codes have shown to be able to simulate turbulence and associated transport in the core of Tokamak devices. However, their application to the edge and scrape-off layer (SOL) region presents significant challenges. To date, only few codes and models have been adapted to SOL/edge conditions. To further study the SOL region in particular, with its steep temperature and density gradients as well as large fluctuation amplitudes, the full-f particle-in-cell code PICLS has been developed. PICLS is based on a full-f gyrokinetic model with linearised field equations, considers kinetic electrons and uses logical sheath boundary conditions. In the past, PICLS was verified by applying it to a well-studied 1D parallel transport problem during an edge-localized mode in the SOL under both collisionless and collisional conditions, for which a Lenard-Bernstein collision operator was implemented. PICLS recently was extended towards three spatial dimensions to study turbulence in open-field-line regions in slab and closed-field-line toroidal geometries. In this work, we will focus on the models and methods we used for extending the code towards three spatial dimensions, including validation efforts and comparisons with other existing codes in closed-field-line geometry