Speaker
Thomas Sunn Pedersen
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I3.009.pdf
First results from divertor operation in Wendelstein 7-X
Thomas Sunn Pedersen , for the W7-X Team.
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Max Planck Institute for Plasma Physics, Greifswald, Germany
Stellarators provide a potentially attractive concept for fusion power production, owing to
their intrinsic steady-state capabilities, and their lack of current-driven disruptions, but high
confinement at high ion temperatures has in the past been an elusive goal, primarily owing
to prompt orbit losses. This issue is addressed in the new generation of optimized
stellarators. Wendelstein 7-X (W7-X) is a highly optimized stellarator experiment that went
into operation in 2015 [1-4]. With a 30 cubic meter volume, a superconducting coil system
operating at 2.5 T, and steady-state heating capability of eventually up to 10 MW, it was
built to demonstrate the benefits of optimized stellarators at parameters approaching those
of a fusion power plant. Operation phase 1.2, which was performed in the second half of
2017, featured the full complement of 10 divertor units, ECRH heating with up to 10
gyrotrons, more than 30 diagnostic systems, and a pellet fueling system. This talk will give
a general overview of the W7-X goals and capabilities, and describe results from the first
divertor operation, including measurements and corrections of error fields, symmetrization
of divertor heat loads, evidence of detachment, and operation at significantly higher
densities (n >10 m ), ion temperatures (T =4 keV), pulse lengths (up to 26 seconds),
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and stored energies (E>1 MJ) than in operation phase 1.1. Various tests of the W7-X
optimization will also be reported, and the results will be put into a broader fusion
perspective. Finally, an outlook towards the future operation phases OP1.2b and OP2 will
be given.
References
[1] T. Klinger et al. Plasma Phys. Controlled Fusion 59(1) 014018 (2017)
[2] H.-S. Bosch et al., Nuclear Fusion 57, 116015 (2017)
[3] R. C. Wolf et al., Nuclear Fusion 57 102020 (2017)
[4] T. Sunn Pedersen et al., Physics of Plasmas 24 055503 (2017)
