1. LRTSG Milestone Review 12/16/10 Lithium Research Topical Science Group FY11-FY12 Milestone Review II Charles Skinner for LRTSG 1/7 Follow up to 11/29/10 LRTSG meeting and 12/10/10 NSTX Team meeting.

2. LRTSG Milestone Review 12/16/10 2/7 Text proposed 12/10/10: R(12-2): Assess the relationship between lithiated surface conditions and edge and core plasma conditions On NSTX, coating the divertor carbon PFCs with evaporated lithium has resulted in transient particle pumping, increased energy confinement, and suppression of edge localized modes (ELMs). To attempt to extend the duration of particle pumping, a liquid lithium divertor (LLD) was installed and commissioned in FY2010. Deuterium pumping will be studied as a function of LLD temperature and divertor electron density and temperature, strike-point location, and flux expansion. These measurements will be compared to retention models. An in-situ materials analysis particle probe (MAPP) situated near the LLD will provide data on surface composition in the outer divertor region under various plasma conditions. The temperature evolution of the LLD surface will be measured to determine its heat transfer properties and allowable peak flux, and to relate the LLD surface temperature to the influx of lithium and hydrogenic species. Finally, lithium transport from the plasma edge to the core will be measured. Improves understanding of Li PFCs, informs Upgrade particle control plans

3. LRTSG Milestone Review 12/16/10 3/7 Some Comments from 12/10/10:Response in new text: Still too much emphasis on the LLD Not such a bad thing. Replace LLD with lithiated surfaces. Uncertainty on LLD cleaning Focus shifted to MAPP Can we really connect lithiated surface measurements in SOL with ‘core and edge plasma conditions’ ? Core and edge transport language deleted. Previous association of MAPP results with retention behavior cited. If core / edge downscaled here it needs to picked up elsewhere. ASC ? How do we measure deuterium pumping ?Recycling and fueling efficiency measurements cited. Start over with new language.See next slide... Lithium transport inconsequential and Li- CHERS may not be available. Li transport deleted Cite C transport instead. Impurity control for density control is going to be important. Hard to fit in without going over length. Open to suggestions ( wait 2 slides... ) Email suggestions from Mike J on recycling, retention and fueling To be discussed.

4. LRTSG Milestone Review 12/16/10 4/7 New language proposed at meeting (sentence by sentence discussion next slides): R(12-2): Investigate the relationship between the atomic composition of lithium conditioned surfaces and the plasma behavior. The plasma facing surface in a tokamak has long been known to have a profound influence on plasma behavior. In turn, the surface is modified by conditioning techniques and by its interaction with the plasma. The development of a predictive understanding of this relationship has been impeded by the lack of diagnostics of the morphology and atomic composition of the plasma facing surfaces. Recently a NSTX probe has been used to expose samples to lithium conditioned plasmas and subsequent analysis has linked surface chemistry to deuterium retention. However with chemically active elements such as lithium, prompt surface analysis is highly advantageous. An in-situ materials analysis particle probe (MAPP) will be installed on NSTX that will enable the exposure of various samples to the SOL plasma near the LLD followed within minutes of plasma exposure by ex-vessel but in-vacuo surface analysis with state of the art tools. Potential reactions between lithium conditioned surfaces and the NSTX base vacuum will be investigated. Correlations between the surface composition and plasma behavior will be explored in conjunction with dedicated lab experiments and modeling. Local and global measurements of fueling efficiency and recycling will be made. The results will deepen the understanding of plasma-wall interactions and inform the plans for particle control in NSTX upgrade. (226 words (was 180))

5. LRTSG Milestone Review 12/16/10 5/7 Sentence by sentence para. 1 as edited at mtg.:Comments/ Suggestions: R(12-2): Investigate the relationship between the composition of lithium conditioned surfaces and the plasma behavior. VS proposes “Assess the impact of Lithium PFC technologies on plasma conditions” May work on alternate text. The plasma facing surface in a tokamak has long been known to have a profound influence on plasma behavior. Agreed ! In turn, the surface is modified by conditioning techniques and by its interaction with the plasma. MB: delete The development of a predictive understanding of this relationship has been impeded by the lack of diagnostics of the morphology and composition of the plasma facing surfaces. Agreed ! Recently a probe has been used to expose samples to NSTX plasmas and subsequent analysis has linked surface chemistry to deuterium retention. Agreed ! However with chemically active elements such as lithium, prompt surface analysis is highly advantageous. Agreed !

6. LRTSG Milestone Review 12/16/10 6/7 Sentence by sentence para. 2 as edited at mtg.:Comments/ Suggestions: An in-situ materials analysis particle probe (MAPP) will be installed on NSTX that will enable the exposure of various samples to the SOL plasma followed within minutes of plasma exposure by ex-vessel but in-vacuo surface analysis with state of the art tools. MB: delete LLD We will investigate reactions between evaporated lithium and plasma facing materials and residual gases in NSTX. MB: We will investigate reactions between evaporated lithium and plasma facing materials and residual gases in NSTX. Correlations between the surface composition and plasma behavior will be explored and compared to laboratory experiments and modeling. Agreed after editing! Measurements of fueling efficiency and recycling will be made. SG questions whether we need to mention fueling efficiency. VS suggests using ‘particle balance’ The results will deepen the understanding of plasma-wall interactions and inform the plans for particle control in NSTX-Upgrade. Agreed after editing!

7. LRTSG Milestone Review 12/16/10 LRTSG consensus text at end of meeting: R(12-2): Investigate the relationship between the composition of lithium conditioned surfaces and the plasma behavior. The plasma facing surface in a tokamak has long been known to have a profound influence on plasma behavior. The development of a predictive understanding of this relationship has been impeded by the lack of diagnostics of the morphology and composition of the plasma facing surfaces. Recently a probe has been used to expose samples to NSTX plasmas and subsequent analysis has linked surface chemistry to deuterium retention. However with chemically active elements such as lithium, prompt surface analysis is highly advantageous. An in-situ materials analysis particle probe (MAPP) will be installed on NSTX that will enable the exposure of various samples to the SOL plasma followed, within minutes of plasma exposure, by ex-vessel but in-vacuo surface analysis with state of the art tools. The reactions between evaporated lithium and plasma facing materials and residual gases in NSTX will be investigated. Correlations between the surface composition and plasma behavior will be explored and compared to laboratory experiments and modeling. Measurements of fueling efficiency and recycling will be made. The results will deepen the understanding of plasma-wall interactions and inform the plans for particle control in NSTX-Upgrade. 7/7