SMuK 2021 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 5: Poster I
P 5.20: Poster
Dienstag, 31. August 2021, 14:00–16:00, P
Statistical analysis of confinement data from pellet fueled high-density plasmas in ASDEX Upgrade — •Tobias Engelhardt1, Peter Lang2, Martin Prechtl1, and ASDEX Upgrade Team2 — 1Hochschule Coburg — 2Max-Planck-Institut für Plasmaphysik
A dataset of pellet-fueled discharges in the high density regime of ASDEX Upgrade (AUG) has been collected, covering 8 years of operation. It comprises scenarios with moderate performance, as well as attempts to achieve high performance by applying either N-seeding or high shaping. This data show that the H06 scaling [1] is more appropriate to describe plasma confinement in this regime, than the H98(y,2) scaling [2]. Additionally, the enhanced confinement gained by the different methods cannot be maintained when the density ne exceeds the Greenwald density nGw.
According to observations at JET (with carbon wall), see e.g. [3], higher H-factors (H98(y,2)) at constant ne/nGw were observed when the triangularity δ was increased. Whether this trend is also present at AUG (with tungsten wall and- divertor) will be investigated. The reduction of confinement when exceeding nGw can possibly be attributed to a rising separatrix density ne,sep. The assumption that primarily the divertor density n0Div influences ne,sep, may turn out to be too shallow. Therefore, potential other correlations between ne,sep and several other plasmaphysical parameters are planned to be analysed.
[1] Johner, FST 59 (2011), 308; [2] IPB, NF 39 (1999), 2175;
[3] Mukhovatov, PPCF 45 (2003), A235