Alcator C-Mod Experiments in Support of the ITER Baseline 15 MA Scenario
Authors: C. E. Kessel, S. M. Wolfe, I. H. Hutchinson, J. W. Hughes, Y. Lin, Y. Ma, D. R. Mikkelsen, F. Poli, M. L. Reinke, S. J. Wukitch, and the C-Mod Team
Abstract:
Experiments on Alcator C-Mod have addressed several issues for the ITER 15 MA
baseline scenario from 2009-2012. Rampup studies show ICRF can save significant V-s, and that
an H-mode in the ramp can be utilized to save 50% more. ICRF modifications to li(1) are
minimal, although the Te profile is peaked relative to ohmic in the plasma center, and alter
sawtooth onset times. Rampdown studies show H-modes can be routinely sustained, avoiding an
OH coil over-current associated with the H-L transition, that fast rampdowns are preferred, the
density drops with Ip, and that the H-L transition occurs at Ploss/Pthr,LH ~ 1.0-1.3 at n/nGr ~ 0.85.
Flattop plasmas targeting ITER baseline parameters have been sustained for 20 τE or 8-13 τCR,
but only reach H98 ~ 0.6 at n/nGr = 0.85, rising to 0.9 at n/nGr = 0.65.
__________________________________________________
Submitted to: Nuclear Fusion (May 2013)
__________________________________________________
Download PPPL-4874 (pdf 2.55 MB 24 pp)
__________________________________________________