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arXiv · 2406.12514

First experimental observation of zonal flows in the optimized stellarator Wendelstein 7-X

D. Carralero·T. Estrada·J. M. García-Regaña·E. Sánchez·T. Windisch·A. Alonso·E. Maragkoudakis·C. Brandt·K. J. Brunner·C. Gallego-Castillo·K. Rahbarnia·H. Thienpondt·the Wendelstein 7-X Team
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Abstract

In this work, we present the first experimental evidence of the presence of zonal flow (ZF) structures in the optimized stellarator Wendelstein 7-X. Using an assortment of diagnostics, flux surface-uniform, electrostatic flow oscillations have been measured, showing a radial scale in the range of tens of ion gyroradii. Such measurements show remarkable agreement with the ZF predicted by local and global non-linear gyrokinetic simulations. These results represent the first direct measurement of ZF in a large stellarator, suitable for the validation of models in reactor relevant conditions.

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D. Carralero, T. Estrada, J. M. García-Regaña, E. Sánchez, T. Windisch, A. Alonso, E. Maragkoudakis, C. Brandt, K. J. Brunner, C. Gallego-Castillo, K. Rahbarnia, H. Thienpondt, the Wendelstein 7-X Team. 2024-06-18. First experimental observation of zonal flows in the optimized stellarator Wendelstein 7-X. https://arxiv.org/abs/2406.12514

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