Electrostatic drift-kinetic simulations of edge localized mode heat pulses in the tokamak scrape-off layer*

For a tokamak operating in high-confinement (H-mode), edge-localized modes (ELM) determine the peak particle  and heat fluxes delivered to the divertor. Parallel heat transport is studied within a one-dimensional drift electrostatic approximation using continuum gyrokinetic code COGENT. We adopt a test problem setup and simulation parameters used by previous authors¹, where the ELM is modeled as a heat and particle source at the midplane of the scrape-off layer. The time evolution of particle and heat fluxes on the target plate is found and compared to results from previous works. The main focus of the research is on the impact of boundary conditions on the heat flux evolution. We considered several modifications of the commonly used logical and insulating sheath boundary conditions and analyzed the overall system behavior. We also investigated different modifications of the gyrokinetic Poisson equation in order to mitigate fast electrostatic shear Alfvén wave and to achieve better quasineutrality conservation. The results of the presented models are in qualitative agreement with previous works.

1. E.L. Shi, A.H. Hakim, G. Hammett, Phys. Plasmas 22, 022504 (2015)