Verification of the PICLS electromagnetic upgrade in mixed variables

Abstract The gyrokinetic particle-in-cell code PICLS is a full-f finite element tool to simulate turbulence in open and closed field lines. During the previous year, the capability of PICLS was extended to encompass electromagnetic effects. Successful tests using the method of manufactured solutions were conducted on the freshly added Ampère’s-law-solver, and shear Alfvén waves were simulated to verify the new electromagnetic time step. However, as a code based on the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mrow> <mml:mo stretchy="false">|</mml:mo> <mml:mo stretchy="false">|</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> -formulation of the gyrokinetic equations, PICLS is affected by the Ampère-cancellation problem. In order to bring higher-beta simulations within reach of our computational capacity, we implemented the mixed-variable formulation with pullback-scheme in a similar fashion to, e.g. EUTERPE, ORB5, or XGC. Here, we present the successful verification of the different electromagnetic formulations of PICLS by simulating shear-Alfvén waves in a test setup designed to minimize kinetic effects.