Supported by Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics NYU ORNL PPPL PSI SNL UC Davis UC Irvine UCLA UCSD U Maryland U New Mexico U Rochester U Washington U Wisconsin Culham Sci Ctr Hiroshima U HIST Kyushu Tokai U Niigata U Tsukuba U U Tokyo Ioffe Inst TRINITI KBSI KAIST ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching U Quebec Recent NSTX Research Progress MHD Confinement Database Transport Edge Pedestal Divertor Sustainment Joint Experiments Ned Sauthoff for the NSTX Team (thanks to Martin Peng and Ed Synakowski)

June 2004NSTX Input to ITPA The NSTX research program is aimed at meeting two broad and related goals Assess the attractiveness of the ST as a fusion energy concept –Component Test Facility and DEMO reactor –Grounded in integration of topical science Use ST plasma characteristics to further a deeper understanding of critical toroidal confinement & high beta plasma physics issues 2 m

Data from 2001 – 3; 2004 data has extended  T to 37 ± 3% Bootstrap fraction up to 50%  N = at I P /aB T0  3 Pulse-length up to 1s Appropriate for ITPA- related studies  T = %  N = 5-6 at I P /aB T0  6 Pulse-length = s  T  2  0  p  / B T0 2 Menard, Sabbagh (Columbia) With NBI Heating, NSTX Achieved Very High , Which Helps Reveal  -Dependence Physics

High-Resolution Rotation, SXR, and In-Vessel B R and B P Sensors Used to Study MHD Physics CHERS shows v  collapse preceding  collapse SXR shows rotating 1/1 mode during v  decay 1/1 Island In-vessel sensors measure rotating mode as v  decays before mode locking Aliased n=1 rotating mode RWM, NTM, 1/1 modes, and rotation physics of high interest to ITER Sabbagh, Bell, Menard, Stutman

Global and Thermal  E ’s Are at Par with Best Tokamak Data, Permitting Low-A Comparisons TRANSP analysis for thermal confinement  E (ms) Compare with ITER scaling for total confinement, including fast ions L-modes have higher non-thermal component and comparable  E ! Kaye

Power Balance During NBI Heating Shows Ions Approaching Neoclassical Transport  ITB in ST? High T i in region  ~ 0.6 – 0.8 indicates  i ~  i ; anomalous ion heating still not ruled out Large separation of  i and  e introduces added opportunities for transport, turbulence, and ITB-verification studies Analyze power balance with TRANSP code –Use measured profiles of T e, T i, n e, n imp, P rad –Monte-Carlo calculation of NBI deposition and thermalization  i   i <<  e AxisEdge LeBlanc et al

Wall Conditioning, Minimal Gas & ELMs Reduce Edge Density and Permit Transport Scaling Studies New high-resolution CHERS confirms large gradients in T i, v i Recipe useful for core transport scaling studies A = 1.5  = 2.3  av = 0.6 q 95 = 4.0 l i = 0.6  N = 5.9%·m·T/MA  T =40% (EFIT) 34% (TRANSP) , 0.55s R.Bell, LeBlanc, Sabbagh, Kaye

June 2004NSTX Input to ITPA A liquid lithium divertor concept may yield a revolutionary solution to particle and heat management Lithium reduces edge influxes, raising the edge temperature. –Transport theory: marginal stability of temperature gradients ==> larger edge T propagates to impressive increases in core (e.g. TFTR) Propose to cycle liquid lithium ==> exhaust heat in the divertor region. Lithium program on NSTX –Li pellets this year –Coatings next year –Studying viability & impact of deploying a liquid Li divertor module system with ALIST group Liquid lithium CDX-U (now LTX) liquid Li tray

Plasma Edge Studies Reveal Turbulence and “Blobs” Important to Divertor Flux Scaling Studies He manifold Side-viewing reentrant window H-mode L-mode Broadly Based Study: Gas Puff Imaging views along field lines (PPPL, LANL) Very fast camera, 10 5 /s (PSI) Reflectometers and edge (UCLA, ORNL) Reciprocating probe (UCSD) Divertor fast camera (Hiroshima U) IR Cameras (ORNL), Filterscope (PPPL) Modeling (PPPL, UCSD, LLNL, Lodestar)

June 2004NSTX Input to ITPA Physics of the edge H mode transition and scrape- off layer transport are being studied by imaging Turbulence illuminated with gas puff at edge, imaged with ultra- fast camera (4  s per frame) Very new data! Task now is to quantify turbulence specta and flows, compare directly with edge turbulence theory Scrape-off-layer intermittency underscore challenge for controlling edge particle & heat fluxes S. Zweben

June 2004NSTX Input to ITPA High harmonic fast waves predicted to propagate in high dielectronic constant plasmas Heating demonstrated over a wide range in wave phase velocity Current drive: well-suited for current drive in plasma ramp-up phase, when energetic ion population is small Evidence for current drive obtained Major participation with Oak Ridge National Laboratory HHFW research is one of two major wave heating & current drive elements in the program Phase of launched wave controllable with multiple- element antenna Electron heating demonstrated

June 2004NSTX Input to ITPA Electron Bernstein wave heating & current drive science being developed for integration & startup goals Learn from stellarator community (W7-AS). Needed for high n e, low B (high  o ) Unique ST feature: may take advantage of high trapped particle fraction to place current where it is needed We are studying the coupling of oblique launch, nearly circularly polarized emissions. Antenna for B-X-O emission studies G. Taylor R. Harvey, Comp-X MIT a collaborative partner in EBW theory Experiments with DIII-D, MAST (UK)

June 2004NSTX Input to ITPA Coaxial helicity injection for plasma startup draws heavily on collaboration U. of Washington is leading development and approaches Create a plasma in the divertor with voltage bias. Have it transport into the vessel via JxB drifts MHD theory: resultant toroidal plasma current is driven by dynamo voltage associated with MHD & reconnection XZ Tang (LANL) and AH Boozer (Columbia), Phys. Plasmas, May 2004 Flux from n = 1 kink Toroidally averaged flux

TaskTitleNSTX LeadStatus MDC-2Joint experiments on RWMSabbaghRWM data being accumulated MDC-4NTM: aspect ratio comparisonGatesUnder consideration CDB-6Improve DB: low AKayeScaling data being accumulated TP-3,4T e ~T i, dominant electron heating; low momentum input LeBlancHHFW H-mode plasma produced, more planned TP-8Non-dimensionally similar ITB- scaling experiments Peng Synakowski NSTX/MAST identity scheduled NSTX/DIII-D scaling scheduled PEP-6Transition threshold comparisonMaingiNSTX/MAST Identity carried out PEP-9A-dependence, wall proximity effectsMaingiNSTX measurements planned DSOL-3Scaling of radial transportZwebenSuggest NSTX contribution DSOL-7Study on separatrix density and edge density profiles BoedoSuggest NSTX contribution DSOL-?Time-resolved impurity depositionSkinnerPropose comparison with AUG DSOL-?Test of “dust buster” at critical placesSkinnerPropose comparison with Tore-Supra SSEP-2Hybrid scenario developmentMenardDIII-D early H-mode scenario tested successfully Status of Joint Experiments (June 2004) Interest in CDB-2 (  -scaling), etc., should be explored.