The 21N-moment multi-temperature collision coefficients for Zhdanov closure

We provide the 21N-moment multi-temperature collision coefficients for the Boltzmann collision operator using the Sonine-Hermite polynomial ansatz in the style of Zhdanov et al. First, we outline the general derivation method. Then, we provide the collision coefficients in the most general form in terms of the Chapman-Cowling integrals for any potential of interaction for the 21N-moment approximation. Then, we provide the collision coefficients for the specific case of the approximated Coulomb potential cross-section with Debye cutoff. These coefficients help in order to find easy implementation in current scrape-off layer/edge fluid packages, which currently implement the 21N-moment single-temperature coefficients. This provides the completion of a missing link in the current literature.