NSTX-U Collaboration Status and Plans for: ORNL Boundary Physics and RF Research J.M. Canik, J.B.O. Caughman, J.-W. Ahn, S.J. Diem, T.K. Gray, D.L. Green, E.F. Jaeger, C.H. Lau, J.D. Lore, A.C. Sontag NSTX-U Collaborator Research Plan Meetings PPPL – LSB B318 April / May 2014 NSTX-U Supported by Culham Sci Ctr York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto U Kyushu U Kyushu Tokai U NIFS Niigata U U Tokyo JAEA Inst for Nucl Res, Kiev Ioffe Inst TRINITI Chonbuk Natl U NFRI KAIST POSTECH Seoul Natl U ASIPP CIEMAT FOM Inst DIFFER ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching ASCR, Czech Rep Coll of Wm & Mary Columbia U CompX General Atomics FIU INL Johns Hopkins U LANL LLNL Lodestar MIT Lehigh U Nova Photonics ORNL PPPL Princeton U Purdue U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Illinois U Maryland U Rochester U Tennessee U Tulsa U Washington U Wisconsin X Science LLC

NSTX-U NSTX-U Collaboration Status and Plans - April / May 2014 Research plans and needs for this year (FY2014) in preparation for NSTX-U operations in FY2015: BP ORNL Boundary Physics collaboration is organized around three themes –Power and particle exhaust –H-mode pedestal research, with an emphasis on the effects of Li –Effects of 3D fields on edge plasma characteristics FY14 research includes analysis of existing NSTX data –ELM heat flux footprint measurements and scaling –SOLPS analysis of impact of Li on divertor heat flux Synergistic work being done to analyze DIII-D detachment –EMC3-EIRENE modeling of impact of 3D fields on detachment Connects to related modeling of puff-induced asymmetries at C-Mod …as well as diagnostic preparations –Primary diagnostic is IR cameras (two fast, two 30 Hz systems) Interfaces with NSTX-U and DAQ need to be finalized 2 nd dual band adapter to be designed and assembled –Two eroding thermocouples installed on inboard, horizontal tile 2

NSTX-U NSTX-U Collaboration Status and Plans - April / May 2014 Boundary Physics Research Plans for FY Extend heat flux, q scaling studies to larger parameter space –LSN vs DN using new fast upper-viewing IR camera –Further measurements and modeling of effect of Li on divertor plasma –ELM heat flux/footprint measurements and scaling Verify cryo physics design and performance –Measure divertor profiles near pump in NSTX-U (instead of project) –Test pumping when cryo available Neutral pressure measurements using new gauges Measure impact on global particle control, compare to Li coatings Experiments and modeling of impact of 3D fields on edge –New experiments measuring impact on pedestal structure and stability, especially at low collisionality (and with NCC?) –Test role of plasma response in heat flux striations/detachment Pedestal structure (esp. with lithium) –Participate in experiments and analysis of pedestal structure at extended parameter range available in NSTX-U –Extend GK modeling of pedestal to include non-local simulations –Explore access to favorable ELM regimes at reduced collisionality 3

NSTX-U NSTX-U Collaboration Status and Plans - April / May 2014 Research plans and needs for this year (FY2014) in preparation for NSTX-U operations in FY2015: RF The ORNL RF collaboration includes the following research: –Assess HHFW heating and current drive for upgraded plasma conditions, including start-up –Perform experiments related to RF/edge plasma interactions to understand and control RF power flow from the antenna to the core –Provide and operate antenna/edge diagnostics: reflectometer and IR camera –Model and evaluate ECH/EBW scenarios and design power transmission system for 28 GHz long-pulse high-power operation FY14 activities have focused on diagnostic preparation, operational experience, and modeling of heating scenarios –The design of the ORNL reflectometer has been upgraded and new parts have been ordered –A new IR camera will be tested during long-pulse operation of a two- element antenna array in the PPPL RF test stand –Near-field plasma-edge diagnostics that can be mounted on the antenna array are being discussed –A combination of NBI/RF heating and current drive is being modeled utilizing FASTRAN/ISP and AORSA for long-pulse/steady state scenarios 4

NSTX-U NSTX-U Collaboration Status and Plans - April / May 2014 RF Research Plans for FY Assess the performance of HHFW heating and current drive at higher magnetic field and its interaction with NBI-driven H-mode operation –Increased magnetic field strength will move propagation cutoff density and decrease loading: coupling efficiency needs to be determined –Determine changes in core coupling and edge power losses –Second neutral beam and higher field (decreased harmonic mode number) will change interaction with fast ions: simulate and validate losses Develop HHFW start-up and ramp-up with CHI and NBI –Use HHFW during current ramp-up to bridge the gap between CHI initiation and NBI heating Provide and operate antenna/edge plasma diagnostics –Install/operate the upgraded reflectometer system to provide plasma density profiles in front of the HHFW array –Install/operate IR camera to monitor temperature distribution on plasma- facing antenna surfaces and RF-induced power deposition in the divertor: couple with array of RF loop and Langmuir probes in divertor Design and evaluation of ECH/EBW system –Model ECH/EBW heating/current drive/start-up scenarios, including launch angle and polarization –Assist in the design/development of 28 GHz transmission/launching system 5

NSTX-U NSTX-U Collaboration Status and Plans - April / May 2014 Ideas to enhance participation in NSTX-U research/program by U.S. Universities, early-career researchers, and students Allow/encourage off-site collaborators to lead research areas and experiments, not just support them –Perspective from doing this as part of a lab: the ability to do fulfilling research from off-site is entirely dependent on the on-site coordination –Could expand pool of potential collaborators (especially part-time), but they may not have a strong on-site personality protecting them –NSTX was good at this, trick is to stay good with more competition Create a standardized, transparent allocation of run time in each TSG Reserved run time (several days?) for university collaborators, students and early-career researchers –In addition to the normally allocated run time for each TSG –Competitively awarded after initial TSG allocation complete –Expected 15 weeks of run time in 2015 (Recent Congressional Budget?) should allow for some flexibility in run time allocation 6