Collisional gyrokinetic full-f particle-in-cell simulations on open field lines with PICLS

TL;DR

This paper introduces a collisional gyrokinetic full-f particle-in-cell simulation code, PICLS, for plasma edge studies, extending previous collisionless models to include collisions with a focus on conservation properties and comparison.

Contribution

The paper develops and demonstrates a collisional model within the PICLS code, enabling more realistic plasma edge turbulence simulations with gyrokinetic PIC methods.

Findings

Implementation of Lenard-Bernstein collision operator

Conservation properties of the collision operator analyzed

Comparison between collisional and collisionless cases presented

Abstract

Applying gyrokinetic simulations for theoretical turbulence and transport studies to the plasma edge and scrape-off layer (SOL) presents significant challenges. To in particular account for steep density and temperature gradients in the SOL, the "full-f" code PICLS was developed. PICLS is a gyrokinetic particle-in-cell (PIC) code and is based on an electrostatic model with a linearized field equation and uses kinetic electrons. In previously published results we were applying PICLS to the well-studied 1D parallel transport problem during an edge-localized mode (ELM) in the SOL without collisions. As an extension to this collision-less case and in preparation for 3D simulations, in this work a collisional model will be introduced. The implemented Lenard-Bernstein collision operator and its Langevin discretization will be shown. Conservation properties of the collision operator as well as a comparison of the collisional and non-collisional case will be discussed.