Multi-Scale Transport and Turbulence Physics in NSTX Stanley M. Kaye For the NSTX Team Tokamak Planning Workshop PSFC, MIT Sept 17, 2007 Supported by Office of Science Culham Sci Ctr U St. Andrews York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto U Kyushu U Kyushu Tokai U NIFS Niigata U U Tokyo JAERI Hebrew U Ioffe Inst RRC Kurchatov Inst TRINITI KBSI KAIST ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching ASCR, Czech Rep U Quebec College W&M Colorado Sch Mines Columbia U Comp-X General Atomics INEL Johns Hopkins U LANL LLNL Lodestar MIT Nova Photonics New York U Old Dominion U ORNL PPPL PSI Princeton U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Maryland U Rochester U Washington U Wisconsin
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Multi-Scale Transport and Turbulence Physics in NSTX Stanley M. Kaye For the NSTX Team Tokamak Planning Workshop PSFC, MIT Sept 17, 2007 Supported by Office.
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Multi-Scale Transport and Turbulence Physics in NSTX
NSTX Can Address T&T Issues Critical to Both Basic Toroidal Confinement and Future Devices
• Critical issues for future (including Burning Plasma) Devices (ST-PE, CTF; ITER)– Confinement enhancement (H-factor) at low & high Pheat/PLH
– Hot-ion H-mode operation - neoclassical ion transport– Maximize neutron production &/or fusion gain – optimize electron
transport– Predictive understanding necessary
• NSTX can address these issues– Dominant electron heating with NBI: relevant to -heating in ITER– Strong rotational shear that can influence transport– Anomalous electron transport can be isolated: ions close to
neoclassical
– Large range of T spanning e-s to e-m turbulence regimes
Verification and validation of theory and models at all levels - Synthetic diagnostics in gyro-kinetic codes - Fluctuation spectra, mode structure - Transport fluxes, ’s, D’s
shear)• HHFW → NBI, Non-Axisymmetric Magnetic Perturbations
(NAMP) braking– nRMP to slow plasma, reduce ExB to point where ion transport
becomes anomalous
– Relation of first low-k turbulence measurements to transport• Low-k fluctuation diagnostic• Full FIDA, neutron collimators for Pheat
– Role of Zonal Flows in edge• Doppler reflectometry, ERD upgrade
– Ion internal transport barrier studies• Relation to current profile, integer q, Zonal Flows• Validation of neoclassical orbit shrinking theory
- Predictive understanding crucial for design/operation of ST-CTF (neoclassical ions)- NSTX tools allow for transitioning between turbulent and neoclassical transport
SMK – TPW 8
Ion Transport Research in Latter Part of Five Year Plan Will Allow Us to Draw Definitive Conclusions Concerning
Neoclassical vs Turbulent Transport
• 2011-2013– More detailed comparison of inferred i and low-k fluctuations to
gyro-kinetic predictions• Comprehensive validation of neoclassical and ITG theories
– Synthetic diagnostics built into G-K codes
• Assessment of non-local transport due to large
• Zonal Flow dynamics in edge and core (test theoretical q-dependence)
– Assessment of ion transport and turbulence levels at high Pheat/PLH at various ExB for establishing physics basis for ST-PE, CTF
• Second beamline• Internal coils for NAMP braking
– Neoclassical theory development with full FLR
• 2013– Low-to-medium k turbulence levels measured with Microwave
Imaging Reflectometer– Ion transport in OH, RF plasmas with Ti/Te<1
NSTX Is In a Strong Position to Study and Understand Electron Transport
Electron transport anomalous: controls BT scaling
Consistent with high-k fluctuations
Low-k microtearing important in “Hybrid” and weak RS discharges
High-k (ETG?) fluctuations seen to increase with increasing R/LTe
14 cm-1
SMK – TPW 10
A Predictive Understanding of Electron Transport is Critical to Optimizing Fusion Gain/Neutron Production for BP Devices
• 2009-2010– ID of TEM/ITG using present high-k system
• Collisionality scans• Establish critical gradient using HHFW to change R/LTe
• Connect to inferred transport levels– Full FIDA, neutron collimators for Pheat(r)
– Role of RS, low order rational q for eITB formation– Microtearing mode ID
• Change driving/damping(?) terms: ExB shear• Initial internal B measurements with MSE
– Perturbative electron transport using ELMs and pellets• High resolution edge SXR• Relation to high-k turbulence
Compare measurements to results of gyrokinetic calcs with built in synthetic diagnostics for V & V
- Electron transport is one of the top research priorities- Anomalous electron transport can be “isolated” (i.e., ion transport neoclassical)
SMK – TPW 11
Electron Transport is One of the Top Research Priorities
• 2010 - 2011– Local modification of electron transport and turbulence
• Low power EBW (200 kW)• Modify q-profile to induce electron ITB• Assess turbulence spreading with low and high-k fluctuation measurements
– Modulated EBW to probe local critical gradient physics• High-resolution Tangential Optical SXR (TOSXR)• Relation to changes in high-k turbulence
– Microtearing mode ID continued• Internal B, low-k for mode structure
– Verify transport trends at high Pheat/PLH
• Second beamline
• 2012 – 2013– Detailed medium-to-high k turbulence with kr & k
• Microwave scattering high-k upgrade• Microwave Imaging Reflectometer• Mode structures, full frequency spectra, dispersion characteristics• Radial streamer ID
– Localized heating to probe critical gradient physics, turbulence spreading• High power EBW (2 MW)
Full V & V critical to effort
SMK – TPW 12
Momentum Transport Studies Will Address Source of High-Rotation and Relation to Energy Transport
i, scaling different at low R/aPerturbed momentum transport studies using nRMP (n=3) braking and spin-up indicates significant inward pinch velocity
Due to ITG suppression?
Is neoclassical?
Peeters et al
Fit with finite v,pinch
Fit with v,pinch=0
TRANSP
• 2009 – 2010 - Validation of neoclassical theory (poloidal CHERS for v) - Determine vpinch, under a variety of conditions
- NAMP for magnetic braking
- Tests of inward pinch theories - Test of NTV theory for magnetic braking - Comparison with initial low-k• 2011-2013 - Relation of vpinch, to low-k in both L and H - Zonal flows/GAMs and relation to other microinstabilities - Further vpinch, assessment (internal NAMP coils for magnetic braking)• 2013 - Intrinsic rotation studies with Imaging X-ray Crystal Spectrometer
SMK – TPW 13
Particle Transport Studies Important for Establishing Regimes of Turbulent vs Neoclassical Transport
Impurity injection experiments/theoretical modeling indicateneoclassical level transport for injected Neon in H-mode - Consistent with neoclassical ion energy transport
• 2009 - 2011 - D & particle transport in core (NBI-fueling dominated) - NUBEAM for S(r) - Relation to thermal , transport, core turbulence (low-k) - Density peaking - Modulated core fueling with beam blips; determination of Dpert, vpinch
- D & particle transport in outer region - S(r) from extended modeling (DEGAS2/UEDGE) - Relation to edge turbulence (Boundary) - Impurity transport using gas puffing, TESPEL, high res SXR to deduce Dpert, vpinch
- Helium transport studies (He puffing or He discharges)
• 2011 – 2013 - Determine role of low-k turbulence in controlling particle transport - Modulated particle transport studies continue with second beamline
Effect of Lithium conditioning
SMK – TPW 14
Theory Tool Development
• 2D/3D state-of-art neutrals package for transport studies (TRANSP)• Full FLR effects for complete non-local neoclassical transport• Gyro-kinetic codes