München 2019 – wissenschaftliches Programm
P 17.3: Vortrag
Donnerstag, 21. März 2019, 15:00–15:25, HS 17
2D impurity ion flow characteristics in different Wendelstein 7-X island divertor configurations — •Valeria Perseo1, Ralf König1, Dorothea Gradic1, Oliver Patrick Ford1, Florian Effenberg2, David Ennis3, and Thomas Sunn Pedersen1 for the The Wendelstein 7-X Team collaboration — 1Max Planck Insitut für Plasmaphysik, Greifswald, Germany — 2University of Wisonsin, Madison, USA — 3Auburn University, Auburn, USA
The last campaign of Wendelstein 7-X (W7-X) was characterized by the island divertor. This concept exploits the stellarator intrinsic magnetic island topology, that is inherently 3D. In this context, a system able to measure 2D Doppler velocity patterns, such as Coherence Imaging Spectroscopy (CIS), is helpful to understand and confirm the basics of the impurity flow physics. The CIS diagnostic is a camera-based interferometer able to detect wavelength variation of the order of tens of pm (∼tens km/s) of an impurity selected by a narrow bandpass filter. A modulation pattern encoding the spectral line properties is generated by the usage of birefringent crystals. Two systems, set up in order to monitor the conditions of the same divertor module from nearly perpendicular lines of sight, have been designed for W7-X. Flows and line emissions have been recorded under different magnetic and plasma configurations, characterizing the behavior of the intrinsic carbon impurities. The measurements are compared with EMC3-EIRENE simulations, highlighting the presence of counter-streaming flows around the magnetic islands.