ENHANCED PERFORMANCE DISCHARGES IN THE DIII-D TOKAMAK WITH LITHIUM WALL CONDITIONING

Lithium wall conditioning has been used in a recent campaign evaluatin g high performance negative central shear (NCS) discharges. During thi s campaign, the highest values of stored energy (4.4 MJ), neutron rate (2.4 x 10(16)/s), and nT(i) tau (7 x 10(20) m(-3) keV s) achieved to date in DIII-D were obtained. High performance NCS discharges was achi eved prior to beginning Lithium conditioning, but it is clear that sho t reproducibility and performance were improved by lithium conditionin g. Central and edge oxygen concentrations were reduced, after lithium conditioning. Lithium conditioning, consisting of up to four pellets i njected at the end of the preceding discharge, allowed the duration of the usual inter-shot helium glow discharge to be reduced and reproduc ible high auxiliary power discharges, P-NBI less than or equal to 22 M W, were obtained with plasma currents up to 2.4 Mg.