FY2004 Research Plan

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FY2004 Research Plan

• S. M. Kaye for the NSTX Research Team
• PPPL, Princeton Univ.
• NSTX PAC-15 Meeting
• Princeton, N.J.
• 12-14 January 2004

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Outline

• 2004 Goals and Capabilities
• Topical area research program is organized by ETs
• and is driven by research milestones
• HHFW/EBW Heating and Current Drive (Taylor, Ryan)
• Non-Solenoidal Startup (M. Bell, Raman)
• MHD (Sabbagh, Gates)
• Transport and Turbulence (Maingi, Stutman)
• Boundary Physics (Kugel, Kaita)
• Integrated Scenario Development (Menard, Wilson)
• Research plan schedule

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Program Planning Steps

• NSTX Research Forum (9/02)
• PAC-13 (9-10/02)
• PAC-14 (1/03)
• Curtailed FY03 run (1-2/03)
• Five Year Plan (6/03)
• NSTX Research Forum (11/03)
• PAC-15 (1/04)
• Plan 18 run weeks in FY04

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Run Plan Addresses Milestones By Exploring
Fundamental ST Physics

• Highest level milestone (FY04-1)
• Assess confinement and stability in NSTX by
  characterizing high confinement regimes with edge
  barriers and by obtaining initial results on the
  avoidance or suppression of plasma pressure
  limiting modes in high-pressure plasmas
• (TT, MHD, ISD)

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Many Topical Areas Have Specific Milestones

• TT (FY04-2)
• Measure long-wavelength turbulence in ST plasmas
  in a range of plasma conditions
• HHFW/EBW, TT (FY04-3)
• Measure plasma current profile modifications
  produced by RF, NBI and ?p techniques
• Solenoid-free startup (FY04-4)
• Conduct initial tests combining available
  techniques to achieve solenoid-free initiation to
  substantial currents
• HHFW/EBW (FY04-5)
• Measure EBW emissions to assess heating and
  current drive requirements

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Run time allocations for FY04 Represent a
Balanced Scientific Approach

• Run Days
• HHFW/EBW 12 days 13
• Solenoid-free startup 11 days 12
• Transport Turbulence 11 days 12
• MHD 11 days 12
• ISD 11 days 12
• Boundary physics 8 days 9
• Enabling/cross-cutting 12 days 13
• Scientific Contingency 14 days 16
• Total 90 days

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Heating and Current Drive (HHFW/EBW)

• Two FY04 milestones
• Measure plasma current profile modifications
  produced by RF,
• Measure EBW emissions to assess coupling
  requirements for heating and current drive
• New capabilities in 2004
• Feedback control of antenna loading to be
  implemented mid-FY04
• MSE (3 ? 10 channels)
• HHFW antenna modified to increase voltage/power
  limit (FY03)
• CURRAY integrated into TRANSP
• Increased use of CURRAY, CQL3D, AORSA1D for
  discharge scenario development (also in ISD)

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HHFW FY04 Research Plan

• HHFW coupling, power deposition and heating
• Establish good coupling for electron heating
• DND
• Explore parametric decay mechanism
• Possible source of edge ion heating
• RF modulation/USXR for PRF(r)
• HHFW Current Drive
• Dependence on power, density,
• temperature and phasing
• Measure j with MSE
• HHFW-only H-mode
• SN, DN target development
• HHFW NBI important for Five Year objectives
• High-bt or high-Te (RS) NBI target

Hot Component
Cold Component
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EBW FY04 Research Plan

• FY2004 research focused on establishing basis for
  high power heating and current drive system
• Demonstrate ?80 B-X and/or B-X-O conversion
• Use limiters to reduce Ln and increase conversion
  efficiency
• Reflectometry to measure Ln
• Local gas feed to ensure adequate density
• Modulate HHFW to suppress edge density
  fluctuations

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Solenoid-Free Startup

• Milestone FY04-4
• Conduct initial tests combining available
  techniques to achieve solenoid-free initiation to
  substantial currents
• New capabilities in 2004
• Co-axial helicity injection
• Capacitor bank for transient CHI (mid-FY04)
• New ceramic insulator (FY03)
• EFIT with open field line current
• 3D modeling of resistive linear and non-linear
  stability
• PF-only startup
• PF4 power supplies for outer PF startup
  (mid-FY04)
• HHFW to assist plasma formation
• DINA calculations (resistive MHD and transport)
  for scenario and control system development

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CHI FY04 Research Plan

• Employ transient CHI scenario
• Continue FY03 expts but with cap bank for rapid
  rate of rise of injector current
• Build on development made in HIT-II
• PF3L to pinch off plasma for closed flux
• Add CHI to inductive discharge
• Gained experience and understanding in HIT-II
  experiments
• Determine need for absorber field nulling coils
• Extended CHI pulse
• Assess new absorber

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PF-Only Startup FY04 Research Plan

• Outer PF startup additional discharge scenario
  development required (TSC, DINA)
• Bipolar BV swing (no field null)
• HHFW/ECH plasma source
• Outboard null
• No PF4 ? 100 kA
• PF4 100s kA
• HHFW assist
• Initiate plasma on outboard side
• Drive 50-100 kA with PF ramping
• Use HHFW to heat and drive current
• further
• HHFW rampup
• Clamp OH current after Ip50-100 kA
• Apply HHFW to heat and drive current

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MHD Stability

• MHD stability a critical part of highest level
  milestone
• .obtaining initial results on the avoidance or
  suppression of plasma pressure limiting modes in
  high-pressure plasmas
• Related research topics
• Influence of shape and rotation on equilibrium
  and stability
• Effect of error fields
• RWM, ELM, NTM physics
• Fast ion MHD
• New capabilities in 2004
• 6 External EF/RWM control coils (developing)
• Fast power supplies for EF/RWM control (summer
  2004)
• MSE (up to 10 channels)
• USXR, FIRETIP upgrades
• Control system upgrade for higher elongation
• Divertor Mirnov arrays, internal RWM sensors
  (FY03)
• EFIT with rotation, expanded data input FLOW
• MARS

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Shape and Rotation Influence Strongly Plasma
Stability

• bN up to 6 achieved at high elongation
• FY04 Research Plan - High-bN
• High-bT _at_ high IN (high k) k?2.4 with improved
  control system
• High-bp through Ip ramp down test effect of
  rotation, R/a on pressure surface shift
• Effect of boundary shape on high-n stability
  (need PF4)

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Shape Rotation FY04 Research Plan (contd)

• Mode saturation due to shear flow possible
  (internal and external)
• Error fields
• Effect of EF correction on plasma rotation, low-n
  stability
• RWM physics
• Mode structure (internal coils)
• RWM dissipation, rotation damping physics
• Fast feedback for active control
• NSTX/DIII-D similarity experiments (ITPA
  priority)
• RWM characteristics, dissipation, etc.
• EF amplification

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Additional MHD Studies

• Fast ion MHD
• Parametric dependence of fast ion losses on Ip,
  BT, q0
• TAE, CAE, GAE
• Suppression of frequency chirping in fishbone
  instabilities
• Non-linear mechanism
• Similarity expt with DIII-D (chirping observed
  on NSTX but not on DIII-D)
• Neoclassical Tearing Mode Onset
• b-scan
• ELM stability vs shaping (piggyback)

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Transport and Turbulence

• FY04-1
• Assess confinement and stability in NSTX by
  characterizing high confinement regimes with edge
  barriers and .
• FY04-2
• Measure long-wavelength turbulence in ST plasmas
  in a range of plasma conditions
• FY04-3
• Measure plasma current profile modifications
  produced by ?p techniques
• Related research topics
• Establish tE and transport scalings
• Study electron transport physics
• Determine influence of Er (wExB) and bT on
  turbulence, transport, L-H transitions and
  pedestals

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Transport and Turbulence

• New capabilities in 2004
• MSE
• 51 channel CHERS (FY03)
• Scanning NPA (FY03)
• Edge Rotation Diagnostic (FY03) - Er
• Prototype neutron collimators
• Upgraded correlation reflectometry long l
  turbulence
• Fixed frequency reflectometers (4) long l
  turbulence
• mm-wave interferometer line-integrated long l
  turbulence
• Upgraded Gas Puff Imaging (GPI), reciprocating
  probe

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Parametric Scaling Trends Have Been Studied
tENSTX-L Ip0.76 BT0.27 PL-0.76

• L-mode scaling presented to PAC13 (10/02) and
  PAC14 (1/03)
• Non-linear H-mode power dependence
• Ip, BT, etc parameter ranges too limited to
  perform meaningful scaling

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tE and Transport Scalings FY04 Research Plan

• Systematic H-mode and ITB studies in quasi-steady
  discharges
• DND to connect to international
• database
• NSTX/MAST identity expts
• ITPA high priority
• NSTX/DIII-D similarity
• R/a effects at fixed bpol, rpol
• Dimensionless scalings
• within NSTX
• OH/NBI R/a
• Initial n, bT (ITPA high priority)

1x
2x
0.5x
c-scalings will also be developed from the
results of these XPs
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tE and Transport Scalings FY04 Research Plan
(contd)

• Scenarios for these studies require development
  of reproducible H-modes L-H threshold studies
• DN, LSN
• Role of shape, fueling type, fueling location
• NSTX/MAST identity (ITPA priority)
• ELM characteristics
• Pedestal characterization
• NSTX/MAST/DIII-D similarity (ITPA priority)

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Electrons Dominate Transport Loss

• Large uncertainties in cs in center and near
  edge due to
• data/equilibrium uncertainties
• 51 point CHERS should help resolve some
  uncertainties
• - Better defined gradients

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Local Transport FY04 Research Plan (contd)

• New diagnostics allow us to investigate the
  relationship between magnetic shear reversal and
  improved electron confinement
• Electron ITB w/NBI, HHFW
• Relation to critical gradient physics
• b scan
• Comparison of NBI vs HHFW transport
• Vary fractions of simultaneous NBI, HHFW power
• Need to develop successful synergistic scenario
• Momentum transport studies

GS2 Calculations
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Core and Edge Turbulence FY04 Research Plan

• New and upgraded diagnostics allow for
  measurement of fluctuations closer to the plasma
  core
• Initially, study L-mode plasmas (low ne NBI RF)
• Combined edge turbulence study
• GPI higher spatial/temporal extent, resolution
• Recip. probe multiple tips to resolve Te, ne and
  Er, Epol, B, Te, fluctuations
• w/Boundary ET

FIRETIP
Reflectometry
Accessibility
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Boundary Physics

• Enabling technology
• Develop and evaluate particle control techniques
• Assess fueling and particle pumping needs
• Evaluate power handling needs and solutions
• Science
• Characterize edge power and particle transport
  regimes
• Measure edge turbulence (with TT)
• New capabilities in 2004
• Low-Z pellet injector (Li/B/C)
• Supersonic gas injector
• Improved boronization schemes
• Upgraded reciprocating probe
• Edge rotation diagnostic (FY03)

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Fueling and Particle Control FY04 Research Plan
Density control a key issue for long pulse
discharges

• Supersonic gas injection to enhance fueling
  efficiency
• Low-Z pellet injector (Li/B/C)
• 10-400 m/sec (controllable), 1 to 8
  pellets/discharge
• Particle control using Li wall coatings
• Characterize low-Z pellet ablation, impurity
  transport
• Improved boronization techniques
• Daily boronization
• Boronization during high temperature bakeout
• More uniform deposition

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Power and Particle Control FY04 Research Plan

• Establish heat flux scaling and power
  accountability
• Parametric scaling (Ip, ne, Pheat)
• H vs non-H, SN/DN configurations
• Detailed edge characterization of edge for SOL
  transport studies
• NSTX/MAST comparative studies
• Test methods for reducing heat flux
• X-point sweeping
• Detached divertor
• Investigate impurity transport
• Sources/sinks of C under
• various conditions
• Connect to edge convective
• transport theory

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Integrated Scenario Development

• Highest level milestone requires integration of
  techniques to produce high performance plasmas
• Simultaneous high-bt, tE for long duration (tFT
  tE)
• NBI/HHFW compatibility
• New capabilities in 2004
• Control system upgrades
• Decreased latency
• HHFW loading, outer gap control
• GA rtEFIT shape control (continuing)
• Improved wall conditioning
• Improved gas injection/density control

New System (
Data Bits
Original System ( 3 msec)
Time (msec)
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ISD 2004 Research Plan

• Control system development
• Shape, vertical control (validate GA MIMO
  feedback algorithm, TSC models)
• Shape optimization predicted to
• improve performance
• High-k/d in DN, LSN (k 2 to 2.4)
• Increased stability limits, higher tpulse, tE
• Long pulse operation can also be aided by
• Early HHFW heating to raise Te
• Reduce OH flux consumption
• Triggering H-mode during Ip ramp
• Broader p(r) ? Higher bpol ? higher I?p
• Possible shear reversal
• HHFW-only H-mode
• Increased Ibs (fBS 0.40 previously)

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ISD 2004 Research Plan (contd)

• HHFW/NBI compatibility desirable for attaining
  ultimate target objectives
• Couple HHFW into high-bT NBI target plasma
• Couple HHFW into low-ne, high-Te (RS) NBI target
  plasma
• Couple NBI into HHFW-driven H-mode
• Application of density control techniques for
  long-pulse operation

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FY04 Research Aimed Towards Early Development of
High-Performance Plasmas
Early Run Mid-Run Late Run
HCD Startup MHD TT Bdy ISD
HHFW conditioning - Decay B-X-O, B-X EBW
HHFWCD w/j(r) measurements HHFW Power
Deposition HHFW NBI
Thermal Ion Htg, CD, HHFW Htg
Efficiency/Ponderomotive Effects
H-mode CHI into inductive
Transient CHI
Absorber null assessment HHFW startup
Solenoid-free startup with PF4 High-bt at
high k NSTX/DIII-D RWM
similarity Stability studies with j(r) meas.
High-bpol aspect ratio effects RWM
dissipation, rotation damping Effect of
boundary on high-n RWM passive stabilization
Neoclassical Tearing Modes
Suppression of fishbone chirping Collective fast
ion loss Active EF/RWM control
NSTX/MAST L-H Core, edge
turbulence NSTX/DIII-D similarity Fast
ion profile PNBI vs PHHFW transport
Dimensionless scaling
in H-mode NSTX/MAST H-mode scaling Electron
ITBs (RS) NSTX/MAST/DIII-D pedestal

Intra-machine R/a scaling
Momentum transport SS Gas Injector
Boronization schemes Density control
Edge turbulence Detached divertor
Boundary characterization Li particle control,
Low-z pellets Control system development
Long-pulse HHFW H-mode USN w/ Reversed BT
High-k LSN, DN Fueling during
long-pulse H-modes HHFW/NBI compatibility
H-mode during Ip ramp

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A Collaborative Control Room Will Aid Run
Productivity
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NSTX Has Developed a Run Plan to Address a Broad
Spectrum of Scientific Issues

• Experiments support the near-term milestones of
  the Five Year research plan
• Experimental proposals will take advantage of
  significant new facility and diagnostic
  capability to probe the underlying physics
• Information will add to the ITPA effort and
  contribute to our understanding of toroidal
  physics
• 18 run weeks will allow us to address most of our
  goals

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ci ? ci, neo near core