Structure-preserving marker-particle discretizations of Coulomb collisions for particle-in-cell codes

Abstract

This paper contributes new insights into discretizing Coulomb collisions in kinetic plasma models. Building on the previous works [1, 2], I propose deterministic discretetime energy-and positivity-preserving, entropy-dissipating marker-particle schemes for the standard Landau collision operator and the electrostatic gyrokinetic Landau operator. In case of the standard Landau operator, the scheme preserves also the discretetime kinetic momentum. The improvements, the extensions of the structure-preserving discretizations in [1,2] to discrete time, are made possible by exploiting the underlying metriplectic structure of the collision operators involved and the so-called discretegradient integrators.