LRTSG meeting to discuss Draft 2014 -2018 5

LRTSG meeting to discuss Draft 2014 -2018 5 -Year Plan Goals and prioritize diagnostics College W&M Colorado Sch Mines Columbia U Comp. X General Atomics INL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics New York U Old Dominion U ORNL PPPL PSI Princeton U Purdue U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Illinois U Maryland U Rochester U Washington U Wisconsin 1. 2. 3. 4. Introduction Rajesh slides Vijay slides Discussion Monday September 12 th at 10: 00 AM Culham Sci Ctr U St. Andrews York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto 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

Overarching issues: • Why lithium in NSTX-U / FNSF-ST ? – Higher plasma performance. – Match to high flux expansion heat flux reduction schemes. • Research questions: – Can Li provide density control over 5 s NSTX-U pulses at high heat flux ? • Do we need a cryopump as well ? – Can Li provide impurity control ? – How should we plan to utilize Li in FNSF / Pilot ?

Lithium-related draft 5 year plan elements (i) • • • • Assess inboard divertor Mo tiles as improved substrate for evaporated Li Test midplane Li granule injector as Li delivery system and for ELM triggering/pacing Assess Li D pumping vs. surface conditions using MAPP probe Test thicker and/or more rapidly deposited Li layers for enhanced D pumping and confinement modifications Assess applicability of Li coatings for pumping Upgrade plasmas, enhance evaporator systems as needed. Design / Fabricate / Install: solid high-Z PFCs for outboard walls Design / Fabricate / Test on test stand / Test in NSTX-U: next-generation liquid lithium systems focusing on continuously refreshed Li for D pumping, and/or flowing Li for divertor heat-flux mitigation. Design / Fabricate / Implement on Upgrade: removable divertor module (RDM). Design/develop methods for increase Li coating coverage of walls (evaporation into neutral gas, Li paint sprayer, upward pointing evaporators). Assess impact of full wall coverage of solid Li on particle pumping, plasma performance. Assess impact of full coverage high-Z PFCs + Li on particle pumping, plasma performance. Assess/design hot wall (using bake-out) capability. Utilize high heat-flux plasma to characterize lithium performance and LLD power handling capabilities. Iterate design. Perform preliminary projection of next-gen LLD to FNSF/Pilot.

LLD to FNSF/Pilot -draft 5 year plan elements (ii) • Utilize hot first-wall capability with Li on high-Z PFCs, assess impact on particle pumping, plasma performance. • Complete design, begin fabrication of complete toroidal coverage nextgeneration LLD for NSTX Upgrade. • Incorporate Li-wall results into other facilities (EAST collaboration), and into designs of FNSF/Pilot and other next-step facilities. • Implement and test full toroidal coverage next-gen LLD for pumping and/or power handling capabilities - project performance to FNSF/Pilot from the diagnostic brainstorming meeting: • MAPP (Materials Analysis Particle Probe) UPGRADE • Laser Induced Break-down Spectroscopy (LIBS) Laser induced ablation spectroscopy (LABS) • Others ? • Opportunities for lab single-issue experiments and prototype testing….

Farrokh Najmabadi: International Fusion Road-mapping Workshop, PPPL, 7 -11 September 2011 advprojects. pppl. gov/Roadmapping/agenda. asp TRLs provide a frame-work for cheaper/faster R&D

Diagnostic Prioritization: Diagnostic solicitation has already published by Do. E. Guidance from Jon: • the point is to discuss the draft goals, modify/improve/delete them, and assess what the diagnostic needs are to support the goals (emphasizing the first few years of 2014 -18). • If possible, prioritize diagnostics - maybe into 2 categories – (1) must have, – (2) would be nice. • Some diagnostics are used by multiple TSGs, so knowing LRTSG priority can influence what diagnostics are agreed to. For example, do you/we want MAPP for the upgrade? if so, should it be modified during outage? etc, etc.

NSTX Supported by Lithium related diagnostics for the 5 year plan College W&M Colorado Sch Mines Columbia U Comp-X General Atomics INL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics New York U Old Dominion U ORNL PPPL PSI Princeton U Purdue U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Maryland U Rochester U Washington U Wisconsin Rajesh Maingi LRTSG planning meeting Princeton, NJ Sept. 12, 2011 Culham Sci Ctr U St. Andrews York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto 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

A few important questions can help guide diagnostic choices • Why does pedestal performance increase continuously with increasing lithium evaporation, beyond implantation range? – Hypothesis: the lithium coverage on the center stack and upper divertor are important; suggests more spectroscopic measurements of these regions – Hypothesis: film in divertor is constantly being eroded and re-distributed; suggests more quantitative work on strike point regions – Hypothesis: something specific to lithium/graphite chemistry and functionality; suggests MAPP like measurement closer to strike point • Does high lithium evaporation limit peak heat flux? – Dual band IR camera data shows reduction of Pdiv with increasing lithium evaporation; need more data analysis of existing data and confirmation of effect when NSTX Upgrade comes on-line; new data from fast eroding thermocouples will be helpful LRTSG diagnostic motivations (Maingi) Sept. 12, 2011 8

A few important questions can help guide diagnostic choices • Will lithium evaporation into upper divertor improve performance? – Discharges without lithium showed peak stored energy near double-null, while discharges with lithium showed peak stored energy with more negative drsep, i. e. lower single null; suggests that some method to evaporate into upper divertor should be considered, along with additional upper divertor diagnostics • What happens to the inner divertor on the vertical part of the center stack with lithium? Does it re-attach? – Additional diagnostics to view the lower (and upper? ) parts of the center stack when the inner leg does not sit on the floor at high triangularity – It would be good if we can determine that re-attachment doesn’t present any problems in double-null, where little power goes to inboard side LRTSG diagnostic motivations (Maingi) Sept. 12, 2011 9

LRTSG diagnostic motivations (Maingi) Sept. 12, 2011 10

LRTSG diagnostic motivations (Maingi) Sept. 12, 2011 11

LRTSG diagnostic motivations (Maingi) Sept. 12, 2011 12