Enhanced confinement discharges in DIII-D with neon and argon induced radiation

Enhanced energy confinement in discharges with impurity induced radiating power fractions, P-rad/P-in, from 50% to 100% have been observed in the DIII-D tokamak with neon and argon gas puffing. These radiating mantle enhanced confinement discharges have been obtained in the DIII-D tokamak under a variety of conditions: diverted and limited configurations with both an H-mode and L-mode edge. Confinement enhancements as high as the ELM free H-mode scaling relation have been obtained with impurity gas puffing, although operation at the highest densities is transient. Similarities and differences between these DIII-D discharges and RI-mode discharges obtained in the TEXTOR tokamak are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.