Kinetic modeling and numerical simulation of plasma-wall interactions in magnetic fusion devices

International audiencePhysical model In this work we apply a 1D3V kinetic model to the study of plasma wall-interactions relevant to magnetic fusion devices such as Tokamaks. The base physical model describes a plasma in contact with one or two parallel planar material walls, standing for divertor targets plates in the two examples considered here. The direction e x normal to the plate(s) is the only one taken into account, while the system is considered invariant in the (e y , e z) plane. In addition to the self-consistent electric field along e x , particles are subject to the action of a uniform external magnetic field B 0 = B 0 (sin αe x + cos αe y) tilted with respect to the wall surface. For a given species of mass m s and charge q s , the evolution of the distribution function g s (t, x, v) in the 4D phase space is driven by the Vlasov equation ∂ t g s + v x ∂ x g s + q s m s (−∂ x φ e x + v × B 0) · ∇g s = C s (g s) + S s , (1) where the self-consistent electrostatic potential φ is obtained by the Poisson equation ∂ xx φ = −(1/ε 0) ∑ s q s n s and (C s , S s) stand respectively for the contribution of collisional processes and external sources. From a computational point of view, the specificity of our approach is the use of fully Eulerian schemes in our computational codes: the particle distribution function is sampled over a 4D phase-space grid. Smooth and accurate solutions can be obtained even in low density regions without the need for any additional smoothing procedure