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)
