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17–22 Oct 2016
Kyoto International Conference Center
Japan timezone

Improving fast-ion confinement in high-performance discharges by suppressing Alfve´n eigenmodes

19 Oct 2016, 14:00
4h 45m
Kyoto International Conference Center

Kyoto International Conference Center

Takaragaike, Sakyo-ku, Kyoto 606-0001 Japan
Poster THW - Magnetic Confinement Theory and Modelling: Wave–plasma interactions; current drive; heating; energetic particles Poster 4

Speaker

Mr Gerrit J. Kramer (Princeton Plasma Physics Laboratory)

Description

The performance of steady-state DIII-D discharges is often reduced due to anomalous fast-ion transport that was observed to correlate with Alfv´en eigenmode (AE) activity. Fast-ion transport modeling using the kick model [1] shows that the observed mode activity can account for the observed fast-ion confinement degradation. Therefore, suppressing the AE activity will improve the plasma performance through improved fast-ion confinement. This can be achieved by modifying the magnetic safety factor profile. In these discharges the q profile has a minimum near r/a = 0.3, in the same region where the fast-ion pressure gradient, which drives the AEs, has its maximum. By moving q_min to a larger minor radius where the fast-ion pressure gradient is small, the drive for the reversed shear AEs weakens and conditions in the core become unfavorable for normal AEs. Experimental evidence will be presented that this solution is viable and that the fast-ion confinement can be restored to near classical levels. This work was supported by the US Department of Energy under DE-AC02-09CH11466, DE-AC52-07NA27344, DE-FC02-04ER54698, and SC-G903402. [1] M. Podesta, et al. (2014) Plasma Phys. and Contr. Fusion 56, 055003
Country or International Organization United States
Paper Number TH/P4-5

Primary author

Mr Gerrit J. Kramer (Princeton Plasma Physics Laboratory)

Co-authors

C. Holcomb (Lawrence Livermore National Laboratory) L. Cui (Princeton Plasma Physics Laboratory) M. Podesta (Princeton Plasma Physics Laboratory) M.A. Van Zeeland (General Atomics) N.N. Gorelenkov (Princeton Plasma Physics Laboratory) R. Nazikian (Princeton Plasma Physics Laboratory) W. Solomon (Princeton Plasma Physics Laboratory) W.W. Heidbrink (University of California-Irvine) Y.B. Zhu (University of California-Irvine)

Presentation materials