1. Supported by Office of Science NSTX S.M. Kaye, PPPL ITPA PPPL 5-7 Oct. 2009 Confinement and Transport in NSTX: Lithiumized vs non-Lithiumized Plasmas Culham Sci Ctr U St. Andrews York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto U Kyushu U Kyushu Tokai U NIFS Niigata U U Tokyo JAEA Hebrew U Ioffe Inst RRC Kurchatov Inst TRINITI KBSI KAIST POSTECH ASIPP ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching ASCR, Czech Rep U Quebec College W&M Colorado Sch Mines Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics New York U Old Dominion U ORNL PPPL PSI Princeton U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Maryland U Rochester U Washington U Wisconsin

2. NSTX Fall 2009 ITPAOct. 5-7, 2009 2 Dual LITERs Replenish Lithium Layer on Lower Divertor Between Tokamak Discharges 2 LITER Canisters Modeled deposition pattern ROTATABLE SHUTTER Electrically-heated stainless-steel canisters with re-entrant exit ducts Mounted 150° apart on probes behind gaps between upper divertor plates Each evaporates 1 – 30 mg/min with lithium reservoir at 520 – 630°C Plumes of lithium vapor are roughly Gaussian in angular distribution Rotatable shutters interrupt lithium deposition during discharges & HeGDC Withdrawn behind airlocks for reloading and initial melting of lithium charge LITERs H. Kugel, L. Zakharov

3. NSTX Fall 2009 ITPAOct. 5-7, 2009 3 Lithium Evaporation Produced Plasmas with Long ELM-free Durations in 2008 and 2009 200 mg of Lithium evaporated between shots P NB from 2 to 6 MW (H-mode accessible with P NB <2 MW with Lithium)

4. NSTX Fall 2009 ITPAOct. 5-7, 2009 4 Lithium Evaporation Led to a Significant Reduction in L-H Power Threshold P LH ~ 2.7 MW NBI without Li evaporation (P heat /n e ~0.9 MW/10 19 m 3 ) ~ 1.4 MW NBI with Li evaporation (0.6 MW/10 19 m 3 ) P LH  n e from HHFW expts Normalize P LH by n e due to density differences between plasmas with and without Li evaporation

5. NSTX Fall 2009 ITPAOct. 5-7, 2009 5 Thermal Energy Confinement Increases With Increasing Lithium Evaporation Most pronounced increase in energy in thermal electrons (broader T e profiles) ~Factor of 2 increase in  E,e over full range of Li deposition Strong increase in core metals, P rad losses for Li  250 mg D. Ding, S. Kaye et al., submitted to PPCF, 2009

6. NSTX Fall 2009 ITPAOct. 5-7, 2009 6 Strong Decrease in  e With Increased Li Deposition At fixed n  T e (removes variation due to explicit dependence of  e on this parameter Decrease in  e also coincides with increase in P rad /P tot –P rad /P tot > 15% only for Li deposition > 250 mg

7. NSTX Fall 2009 ITPAOct. 5-7, 2009 7 Higher percentage of  i closer to neoclassical with than without Li Improvement Also Seen in Thermal Ion Transport

8. NSTX Fall 2009 ITPAOct. 5-7, 2009 8 Plans for 2010 Installation of Liquid Lithium Divertor (LLD) –Should allow for operation at lower collisionality –Test strong collisionality scaling (B  E ~   1 ) Implementation of BES diagnostic –In addition to high-k scattering, will cover wide range of k-space for turbulence measurements 2010-11

9. NSTX Fall 2009 ITPAOct. 5-7, 2009 9 Explicit Dependence of  e on n  T e Observed Important to constrain on n  T e when investigating trends

10. NSTX Fall 2009 ITPAOct. 5-7, 2009 10 Explicit Dependence of  e on Current Profile Found Transport reduced with higher current density, and vice-versa 0.9 MA 1.1 MA