(EXP1/04) High Performance H-mode Plasmas at Densities above the Greenwald
Limit
M. A. Mahdavi1), T. H. Osborne1),
A. W. Leonard1), M. S. Chu1),
E. J. Doyle2), M. E. Fenstermacher3),
G. R. McKee4), G. M. Staebler1),
T. W. Petrie1), M. R. Wade5),
S. L. Allen3),
J. A. Boedo6), N. H. Brooks1),
R. J. Colchin5), T. E. Evans1),
C. M. Greenfield1), G. D. Porter3),
R. C. Isler5), R. J. La Haye1),
C. J. Lasnier3), R. Maingi5),
R. A. Moyer6), M. Schaffer1),
P. G. Stangeby7), J. G. Watkins8),
W. P. West, D. G. Whyte6), and
N. S. Wolf3)
1) General Atomics, San Diego, California USA
2) University of California-Los Angeles, Los Angeles, California USA
3) Lawrence Livermore National Laboratory, Livermore, California USA
4) University of Wisconsin-Madison, Madison, Wisconsin USA
5) Oak Ridge National Laboratory, Oak Ridge, Tennessee USA
6) University of California-San Diego, La Jolla, California USA
7) University of Toronto Institute for Aerospace Studies, Toronto,
Canada
8) Sandia National Laboratories, Albuquerque, New Mexico USA
Abstract. Densities up to 40 percent above the Greenwald limit are
reproducibly achieved in high confinement (
HITER89p = 2) ELMing
H-mode discharges. Simultaneous gas fueling and divertor pumping were used
to obtain these results. Confinement of these discharges, similar to
moderate density H-mode, is characterized by a stiff temperature profile,
and therefore sensitive to the density profile. A particle transport model
is presented that explains the roles of divertor pumping and geometry for
access to high densities. Energy loss per ELM at high density is a factor of
five lower than predictions of an earlier scaling, based on data from lower
density discharges.
IAEA 2001
