SMuK 2023 – scientific programme
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P: Fachverband Plasmaphysik
P 10: Magnetic Confinement III/HEPP V
P 10.2: Talk
Wednesday, March 22, 2023, 11:30–11:55, CHE/0091
Determination of SOL filament cooldown at ASDEX Upgrade — •Daniel Wendler1,2, Michael Griener1, Gregor Birkenmeier1,2, Elisabeth Wolfrum1, Ulrich Stroth1,2, and the ASDEX Upgrade team3 — 1Max-Planck-Institut für Plasmaphysik, Garching — 2Physik-Department E28, Technische Universität München, 85747 Garching, Germany — 3See author list of U. Stroth et al. 2022 Nucl. Fusion 62 042006
Filaments, alternatively called blobs, are coherent structures, appearing in the scrape-off layer (SOL) of magnetic fusion devices in all plasma scenarios. They have a higher pressure than the background plasma and a radial motion outwards, which also differs from the background. As a consequence, blobs cause convective transport, being correlated with phenomena like the density shoulder formation and in general the power deposition in the plasma vessel. To better estimate the power transported by the filaments, their temperatures, densities and velocities are measured. This is done by means of a two-dimensional grid of lines of sight at the ASDEX Upgrade thermal helium beam. Measured radiances of helium transitions are then converted into the plasma electron temperature and density by applying a collisional radiative model. Via the calculation of the temporal evolution of these quantities and the blob position, the convective power of the filament is determined. This shows a cooldown of the filament's temperature which is combined with a loss of density. These processes are compared to analytical models, allowing to determine the temporal evolution of the convective power.