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.

本文为动力学等离子体模型中库仑碰撞的离散化提供了新的见解。在之前的工作（Carrillo等人2020 J. Comput. Phys. X 7 100066；Hirvijoki 和 Burby 2020 Phys. Plasmas 27 082307）的基础上，我提出了确定性离散时间能量和正性保持、熵粒子消散标记标准 Landau 碰撞算子和静电陀螺运动 Landau 算子的方案。在标准 Landau 算子的情况下，该方案还保留了离散时间动量。Carrillo等人(2020 J. Comput. Phys. X)的结构保留离散化的改进和扩展7 100066) 以及 Hirvijoki 和 Burby (2020 Phys. Plasmas 27 082307) 到离散时间，通过利用所涉及的碰撞算子和所谓的离散梯度积分器的潜在三方结构成为可能。