Publications in Scientific Journals:
F. Laggner, S. Keerl, J. Gnilsen, E. Wolfrum, M. Bernert, D. Carralero, L. Guimarais, V. Nikolaeva, S. Potzel, M. Cavedon, F. Mink, M. Dunne, G. Birkenmeier, R. Fischer, E. Viezzer, M. Willensdorfer, M. Wischmeier, F. Aumayr, -. EUROfusion MST1 Team, . ASDEX Upgrade Team:
"Divertor, scrape-off layer and pedestal particle dynamics in the ELM cycle on ASDEX Upgrade";
Plasma Physics and Controlled Fusion,
In addition to the relaxation of the pedestal, edge localised modes (ELMs) introduce changes to
the divertor and scrape-off layer (SOL) conditions. Their impact on the inter-ELM pedestal
recovery is investigated, with emphasis on the electron density (ne) evolution. The typical ELM
cycle occurring in an exemplary ASDEX Upgrade discharge interval at moderate applied gas
puff and heating power is characterised, utilising several divertor, SOL and pedestal diagnostics.
In the studied discharge interval the inner divertor target is detached before the ELM crash, while
the outer target is attached. The particles and power expelled by the ELM crash lead to a reattachment
of the inner target plasma. After the ELM crash, the outer divertor target moves into a
high recycling regime with large ne in front of the plate, which is accompanied by high main
chamber neutral fluxes. On similar timescales, the inner target fully detaches and the high field
side high density region (HFSHD) is formed reaching up to the high field side midplane. This
state evolves again to the pre-ELM state, when the main chamber neutral fluxes are reduced later
in the ELM cycle. Neither the timescale of the appearance of the HFSHD nor the increase of the
main chamber neutral fluxes fit the timescale of the ne pedestal, which is faster. It is found that
during the ne pedestal recovery, the magnetic activity at the low field side midplane is strongly
reduced indicating a lower level of fluctuations. A rough estimation of the particle flux across the
pedestal suggests that the particle flux is reduced in this period.
Created from the Publication Database of the Vienna University of Technology.