- Luce, TC;
- Wade, MR;
- Politzer, PA;
- Allen, SL;
- Austin, ME;
- Baker, DR;
- Bray, B;
- Brennan, DP;
- Burrell, KH;
- Casper, TA;
- Chu, MS;
- DeBoo, JC;
- Doyle, EJ;
- Ferron, JR;
- Garofalo, AM;
- Gohil, P;
- Gorelov, IA;
- Greenfield, CM;
- Groebner, RJ;
- Heidbrink, WW;
- Hsieh, C-L;
- Hyatt, AW;
- Jayakumar, R;
- Kinsey, JE;
- La Haye, RJ;
- Lao, LL;
- Lasnier, CJ;
- Lazarus, EA;
- Leonard, AW;
- Lin-Liu, YR;
- Lohr, J;
- Mahdavi, MA;
- Makowski, MA;
- Murakami, M;
- Petty, CC;
- Pinsker, RI;
- Prater, R;
- Rettig, CL;
- Rhodes, TL;
- Rice, BW;
- Strait, EJ;
- Taylor, TS;
- Thomas, DM;
- Turnbull, AD;
- Watkins, JG;
- West, WP;
- Wong, K-L
Significant progress in obtaining high performance discharges lasting many energy confinement times in the DIII-D tokamak has been realized in recent experimental campaigns. Normalized performance ∼10 has been sustained for more than 5>E with qmin > 1.5. (The normalized performance is measured by the product βNH89, indicating the proximity to the conventional β limits and energy confinement quality, respectively.) These H mode discharges have an ELMing edge and β < 5%. The limit to increasing β is a resistive wall mode, rather than the tearing modes as previously observed. Confinement remains good despite qmin > 1. The global parameters were chosen to optimize the potential for fully non-inductive current sustainment at high performance, which is a key program goal for the DIII-D facility. Measurement of the current density and loop voltage profiles indicate that ≈75% of the current in the present discharges is sustained non-inductively. The remaining ohmic current is localized near the half-radius. The electron cyclotron heating system is being upgraded to replace this remaining current with ECCD. Density and β control, which are essential for operating advanced tokamak discharges, were demonstrated in ELMing H mode discharges with βNH89 ≈ 7 for up to 6.3 s or ≈34τE. These discharges appear to have stationary current profiles with qmin ≈ 1.05 in agreement with the current profile relaxation time ≈1.8 s.