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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 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 SOL/edge fluid packages which currently implement the 21N-moment single-temperature coefficients. This provides the completion of a missing link in the current literature., Comment: 19 pages, 0 figures. Accepted by Contributions to Plasma Physics (Dec 2021)

International audience

15th International Workshop on Plasma Edge Theory in Fusion Devices (PET), Nara Kasugano Int Forum IRAKA, Nara, JAPAN, SEP 09-11, 2015; International audience; The impact of a 3D localized particle source on the edge plasma in 3D global turbulence simulations is investigated using the TOKAM3X fluid code. Results apply to advanced fueling methods such as Supersonic Molecular Beam Injection (SMBI) or pellets injection. The fueling source is imposed as a volumetric particle source in the simulations so that the physics leading to the ionization of particles and its localization are not taken into account. As already observed in experiments, the localized particle source strongly perturbs both turbulence and the large scale organization of the edge plasma. The localized increase of the pressure generated by the source drives sonic parallel flows in the plasma, leading to a poloidal redistribution of the particles on the time scale of the source duration. However, the particle deposition also drives localized transverse pressure gradients which impacts the stability of the plasma with respect to interchange processes. The resulting radial transport occurs on a sufficiently fast time scale to compete with the parallel redistribution of particles, leading to immediate radial losses of a significant proportion of the injected particles. Low Field Side (LFS) and High Field Side (HFS) injections exhibit different dynamics due to their interaction with curvature. In particular, HFS particle deposition drives an inward flux leading to differences in the particle deposition efficiency (higher for HFS than LFS). These results demonstrate the importance of taking into account plasma transport in a self-consistent manner when investigating fueling methods. ((c) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Stark broadening of atomic lines in plasmas is investigated by generating the electric microfield with a renewal process. In this model, the microfield is stepwise constant, with jumping times sampled from a waiting time distribution (WTD). Our model is a true simulation of the renewal process, using random number generators for generating different probability density functions (PDF). The use of an equilibrium static microfield PDF and an exponential waiting time distribution reproduces the so called model microfield method (MMM) results. The work presented is an application to the hydrogen Lyman-α line, for which we compare our renewal process model and ab initio simulations calculations, with the aim of studying the role of non exponential waiting time distributions.