Vlasov modelling of parallel transport in a tokamak scrape-off layer

Giovanni Manfredi (1) , Sever Adrian Hirstoaga (2) , Stéphane Devaux (3)

1 IPCMS - Institut de Physique et Chimie des Matériaux de Strasbourg
2 CALVI - Scientific computation and visualization
3 JET-EFDA - Joint European Torus

A one-dimensional Vlasov-Poisson model is used to describe the parallel transport in a tokamak scrape-off layer. Thanks to a recently-developed `asymptotic-preserving' numerical scheme, it is possible to lift numerical constraints on the time step and grid spacing, which are no longer limited by, respectively, the electron plasma period and Debye length. The Vlasov approach provides a good velocity-space resolution even in regions of low density. The model is applied to the study of parallel transport during edge-localized modes (ELMs), with particular emphasis on the particles and energy fluxes on the divertor plates. The numerical results are compared to analytical estimates based on a free-streaming model, with good general agreement. An interesting feature is the observation of an early electron energy flux, due to suprathermal electrons escaping the ions' attraction. In contrast, the long-time evolution is essentially quasi-neutral and dominated by the ion dynamics.

Mots clés: Plasma physics; Transport; Edge-localized modes; Vlasov-Poisson model; Numerical simulation

Domaines: Physique des plasmas [physics.plasm-ph]; Equations aux dérivées partielles [math.AP]

Giovanni Manfredi, Sever Adrian Hirstoaga, Stéphane Devaux. Vlasov modelling of parallel transport in a tokamak scrape-off layer. Plasma Physics and Controlled Fusion, 2011, 53 (1), pp.015012. ⟨10.1088/0741-3335/53/1/015012⟩. ⟨hal-00538153⟩