supported by columbia u comp-x general atomics inel johns hopkins u lanl llnl lodestar mit nova...
TRANSCRIPT
Supported by
Columbia UComp-X
General AtomicsINEL
Johns Hopkins ULANLLLNL
LodestarMIT
Nova PhotonicsNYU
ORNLPPPL
PSISNL
UC DavisUC Irvine
UCLAUCSD
U MarylandU New Mexico
U RochesterU Washington
U WisconsinCulham Sci Ctr
Hiroshima UHIST
Kyushu Tokai UNiigata U
Tsukuba UU TokyoIoffe Inst
TRINITIKBSI
KAISTENEA, Frascati
CEA, CadaracheIPP, Jülich
IPP, GarchingU 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 2004 NSTX 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 = 5-6.2 at IP/aBT0 3
• Pulse-length up to 1s
• Appropriate for ITPA-related studies
T = 30 - 35 %
• N = 5-6 at IP/aBT0 6
• Pulse-length = 0.3-0.4s
T 20p / BT02
Menard, Sabbagh (Columbia)
With NBI Heating, NSTX Achieved Very High ,Which Helps Reveal -Dependence Physics
High-Resolution Rotation, SXR, and In-Vessel BR and BP Sensors Used to Study MHD Physics
CHERS shows v collapse
preceding collapse
SXR shows rotating 1/1mode during v decay
1/1 Island
In-vessel sensors measurerotating 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 BestTokamak Data, Permitting Low-A Comparisons
• TRANSP analysis for thermal confinement
E<
ther
mal
> (
ms)
E<ITER-H98p(y,2)> (ms)
12080400
120
80
40
0
• 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 Ti in region ~ 0.6 – 0.8 indicates i ~ i<NC>; 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
Te, Ti, ne, nimp, Prad
– Monte-Carlo calculation of
NBI deposition and
thermalization
• i<NC> i << e
Axis Edge
LeBlanc et al
Wall Conditioning, Minimal Gas & ELMs Reduce Edge Density and Permit Transport Scaling Studies
• New high-resolution CHERS confirms large gradients in Ti, vi
• Recipe useful for core transport scaling studies
• A = 1.5
• = 2.3
• av = 0.6
• q95 = 4.0
• li = 0.6
• N = 5.9%·m·T/MA
• T = 40% (EFIT)34%
(TRANSP)
112600, 0.55s112600, 0.55s
R.Bell, LeBlanc, Sabbagh, Kaye
June 2004 NSTX 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
Liquidlithium
CDX-U (now LTX) liquid Li tray
Plasma Edge Studies Reveal Turbulence and“Blobs” Important to Divertor Flux Scaling Studies
He manifold
Side-viewingreentrant window
H-mode
L-mode
Broadly Based Study:
• Gas Puff Imaging views along field lines (PPPL, LANL)
• Very fast camera, 105/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)
105710
June 2004 NSTX 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
QuickTime™ and aYUV420 codec decompressor
are needed to see this picture.
S. Zweben
June 2004 NSTX 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 2004 NSTX 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 ne, 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 theoryExperiments with DIII-D, MAST (UK)
Task Title NSTX Lead Status
MDC-2 Joint experiments on RWM Sabbagh RWM data being accumulated
MDC-4 NTM: aspect ratio comparison Gates Under consideration
CDB-6 Improve DB: low A Kaye Scaling data being accumulated
TP-3,4 Te~Ti, dominant electron heating; low momentum input
LeBlanc HHFW H-mode plasma produced, more planned
TP-8 Non-dimensionally similar ITB-scaling experiments
Peng
Synakowski
NSTX/MAST identity scheduled NSTX/DIII-D scaling scheduled
PEP-6 Transition threshold comparison Maingi NSTX/MAST Identity carried out
PEP-9 A-dependence, wall proximity effects Maingi NSTX measurements planned
DSOL-3 Scaling of radial transport Zweben Suggest NSTX contribution
DSOL-7 Study on separatrix density and edge density profiles
Boedo Suggest NSTX contribution
DSOL-? Time-resolved impurity deposition Skinner Propose comparison with AUG
DSOL-? Test of “dust buster” at critical places
Skinner Propose comparison with Tore-Supra
SSEP-2 Hybrid scenario development Menard DIII-D early H-mode scenario tested successfully
Status of Joint Experiments (June 2004)
Interest in CDB-2 (-scaling), etc., should be explored.