Structure-preserving marker-particle discretizations of Coulomb collisions for particle-in-cell codes
Eero Hirvijoki
Abstract
Abstract This paper contributes new insights into discretizing Coulomb collisions in kinetic plasma models. Building on the previous works (Carrillo et al 2020 J. Comput. Phys. X 7 100066; Hirvijoki and Burby 2020 Phys. Plasmas 27 082307), I propose deterministic discrete-time energy- and positivity-preserving, entropy-dissipating marker-particle schemes for the standard Landau collision operator and the electrostatic gyrokinetic Landau operator. In the case of the standard Landau operator, the scheme preserves also the discrete-time kinetic momentum. The improvements, the extensions of the structure-preserving discretizations by Carrillo et al (2020 J. Comput. Phys. X 7 100066) and Hirvijoki and Burby (2020 Phys. Plasmas 27 082307) to discrete time, are made possible by exploiting the underlying metriplectic structure of the collision operators involved and the so-called discrete-gradient integrators.