Distinct from conventional Eulerian 2D fluid solvers, applied routinely to magnetic fusion edge plasma studies, complex 3D magnetic topologies are currently treated by the geometrically more flexible ...Lagrangian schemes, supplemented by Monte Carlo procedures for higher order derivatives (dissipative terms due to diffusion processes) and sources. These particle based algorithms are combined with a field line reconstruction technique for dealing with partially ergodic magnetic fields, involving field aligned regular grids. A generalization to block-structured grids is carried out, which greatly enhances the applicability range of present 3D fusion plasma edge codes, in particular also to poloidally magnetic diverted configurations, as currently envisaged for the largest magnetic fusion device under construction: ITER.
We present the application of an improved EDGE2D-EIRENE SOL transport model for the ELM phase utilizing kinetic correction of the sheath-heat-transmission coefficients and heat-flux-limiting factors ...used in fluid SOL modelling. With a statistical analysis over a range of similar type-I ELMy H-mode discharges performed at the end of the first JET ITER-like wall campaign, we achieved a fast (Δt=200μs) temporal evolution of the outer midplane ne and Te profiles and the target-heat and particle-flux profiles, which provides a good experimental data set to understand the characteristics of an ELM cycle. We will demonstrate that these kinetic corrections increase the simulated heat-flux-rise time at the target to experimentally observed times but the power-decay time at the target is still underestimated by the simulations. This longer decay times are potentially related to a change of the local recycling coefficient at the tungsten target plate directly after the heat pulse.
•Improvements of kinetic ion transport module in guiding centre approximation in EMC3-EIRENE.•Validation of the kinetic ion transport module against magnetic moment conservation and formation of ...banana-orbits.•First stable simulation of Nitrogen seeding for ITER L-mode scenario with the improved kinetic ion transport module of EMC3-EIRENE.
•Monte Carlo DIVIMP and multi-fluid EDGE2D-EIRENE treatment of tungsten were compared.•Tungsten density predictions by DIVIMP and EDGE2D-EIRENE agree within a factor of 2.•DIVIMP predicts ...consistently 50% more tungsten than EDGE2D-EIRENE in attached plasmas.•The discrepancy is due to the bundling of tungsten charge states to 6 fluid species.•Using 22 tungsten species yields accurate tungsten charge but causes numerical errors.
The average tungsten concentrations in the pedestal region (cW) predicted by the Monte Carlo code DIVIMP and the coupled multi-fluid plasma/kinetic neutral code EDGE2D-EIRENE are found to agree within a factor of 2 for a range of JET-ILW L-mode and H-mode plasma conditions. Under attached divertor conditions with cW exceeding 10−6, the cW predicted by DIVIMP is consistently ~50% higher than by EDGE2D-EIRENE. In colder plasma scenarios with cW<10-6, stochastic variations exceed the systematic disagreement between the two codes. The average tungsten charge predicted by EDGE2D-EIRENE in the upstream scrape-off layer is lower by 40–50% due to the bundling of the 74 tungsten ion charge states into 6 fluid species, which explains the reduced tungsten accumulation in the main plasma compared to the DIVIMP predictions.
PDF
