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R. C. Wolf, O. Gruber, R. Dux,
S. Günter, A. Kallenbach, K. Lackner,
M. Maraschek, H. Meister, G. Pereverzev, F. Ryter,
U. Seidel, S. Sesnic, J. Schweinzer,
A. Stäbler, J. Stober, W. Ullrich, and the
ASDEX Upgrade Team
Max-Planck-Institut für Plasmaphysik, EURATOM-Association, D-85748 Garching, Germany
Abstract. Discharges with improved core confinement by a modification of the
current profile using additional heating in the current ramp-up phase have
been investigated. In plasmas with internal transport barriers and L-mode edge
central ion temperatures up to 15 keV, corresponding to ion thermal
conductivities at neoclassical values, have been achieved transiently.
Stationary discharges with H-mode edge and internal transport barrier with
central values of
Ti = 10 keV and
Te = 6.5 keV could be
maintained for 6 s, only limited by the given duration of the neutral beam
injection, which corresponds to 40 confinement times or 2.4 resistive time
scales for internal current diffusion. In this regime of operation not only
the ion thermal conductivity is approaching neoclassical value but also the
electron transport is significantly reduced.
IAEA 2001
