Hannover 2020 – scientific programme
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P: Fachverband Plasmaphysik
P 5: Poster Session 1
P 5.15: Poster
Monday, March 9, 2020, 16:30–18:30, Empore Lichthof
Core plasma density fluctuations in Wendelstein 7-X — •Jan-Peter Bähner1, Adrian von Stechow1, Zhouji Huang2, Jorge Alcuson1, Eric Edlund3, Miklos Porkolab2, Olaf Grulke1,4, and The W7-X Team1 — 1Max-Planck-Institut für Plasmaphysik, Greifswald, Germany — 2MIT Plasma Science and Fusion Center, Cambridge, MA, USA — 3SUNY Cortland, Cortland, NY, USA — 4Technical University of Denmark, Kongens Lyngby, Denmark
Recent analysis of Wendelstein 7-X experiments have shown that the ion heat diffusion in W7-X is dominated by anomalous transport processes.
Consequently, the ion temperature is significantly smaller than expected from neoclassical transport estimates.
Ion-scale turbulence is expected to be the main driver for anomalous transport, with the major instabilities on this scale being the ion temperature gradient (ITG) driven mode and the trapped electron mode (TEM).
The Phase Contrast Imaging (PCI) diagnostic provides density fluctuation measurements with temporal and wavenumber resolution spanning the ITG and TEM scales.
A recent calibration of the wavelengths and relative fluctuation amplitudes measured by PCI for the majority of W7-X discharges enables a comparison of density fluctuations between a wide range of discharges.
Investigations on the impact of magnetic configuration, heating power and density on the density fluctuations are presented, as well as linear growth rate calculations.
Core plasma turbulence in W7-X will be characterized by fluctuation level, dominant phase velocity, and wavenumber distribution.