Quasistationary high confinement discharges with trans-greenwald density on TEXTOR-94
Confinement quality as good as ELM-free H-mode at densities substantially above the Greenwald density limit ( &nmacr;(e,0)/n(GW) = 1.4) has been obtained in discharges with a radiative boundary under quasistationary conditions for 20 times the energy confinement time. This is achieved by optimizing the gas-fueling rate of RI-mode discharges which tailors their favorable energy confinement and leads to discharges with beta values just below the operational limit beta(n) = 2 of TEXTOR-94, thereby effectively avoiding confinement back transitions or disruptions. In addition, this high-density regime is favorable for helium removal and results in figures of merit tau(*)(p,He)/tau(E) approximately 10-15, relevant for a future fusion power reactor.
Mank
G
Institut fur Plasmaphysik, Forschungszentrum Julich GmbH, EURATOM Association, D-52425 Julich, Germany.
Messiaen
AM
Ongena
J
Unterberg
B
Dumortier
P
Finken
KH
Jaspers
R
Koslowski
HR
Kramer-Flecken
A
Rapp
J
Samm
U
van Wassenhove G
Weynants
RR