Comparison of fluid and kinetic models of target energy fluxes during ELMs

Comparison of fluid and kinetic models of target energy fluxes during ELMs

Comparison of fluid and kinetic models of target energy fluxes during ELMs 150 150 Mathew

Comparison of fluid and kinetic models of target energy fluxes during ELMs

Parallel transport associated with Type I ELM filaments in the scrape-off layer (SOL) is studied by means of three computational approaches – fluid, Vlasov and particle-in-cell (PIC). These techniques are benchmarked for convective transients by analyzing power fluxes at the target. In spite of kinetic effects due to fast electrons which are not captured in the fluid code, the overall agreement between the codes is satisfactory. In addition, the collisionless Vlasov model agrees well with an analytic free-streaming model. The total peak energy flux at the target is comparable between the models, but the individual fractions of the flux carried by ion and electron components are determined by kinetic effects and processes in the sheath and the energy source in the fluid code is redistributed between electrons and ions in order to obtain the best match with the PIC model. From results for convective ELMs, approximate expressions for the energy fluence and the peak energy flux at the target are derived. Additionally, conductive ELMs are studied.

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01/01/2012