Scrape off layer (SOL) transport and filamentary dynamics in high density tokamak regimes

Scrape off layer (SOL) transport and filamentary dynamics in high density tokamak regimes

Scrape off layer (SOL) transport and filamentary dynamics in high density tokamak regimes 150 150 amit

A detailed cross-device investigation on the role of filamentary dynamics in high density regimes has been performed within the EUROfusion framework comparing ASDEX-Upgrade (AUG) and TCV tokamaks. Both devices have run density ramp experiments at different levels of plasma current, keeping toroidal field or q95 constant in order to disentangle the roles of parallel connection length and the current. In both devices, with constant toroidal field, SOL profiles tend to flatten at lower edge density whenever current is reduced even though the behavior is reconciled in terms of Greenwald fraction whereas the runs at constant q95 exhibit unclear results whenever both devices are considered. ASDEX-Upgrade has also explored the filamentary behavior in inter-ELM regimes in H-Mode. The experiments on AUG focused on the role of neutrals, performing discharges both with and without the cryopumps, highlighting the how large neutral pressure not only in the divertor but at the midplane is needed in order to develop H-Mode SOL profile shoulder in AUG. Finally particle acceleration during the eruption of ELM filaments has been investigated in order to understand the possible impact on Plasma Facing Components of accelerated electrons and ions in the SOL.

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Conference:
27th IAEA Fusion Energy Conference, Ahmedabad, India, 22-27 October 2018
Published date:
22/01/2021