FY 2004 Research Plan S M Kaye for

FY 2004 Research Plan S. M. Kaye for the NSTX Research Team PPPL, Princeton Univ. NSTX PAC-15 Meeting Princeton, N. J. 12 -14 January 2004 1 SMK – PAC 15 1

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 2 SMK – PAC 15 2

Program Planning Steps • • NSTX Research Forum (9/02) PAC-13 (9 -10/02) PAC-14 (1/03) Curtailed FY 03 run (1 -2/03) Five Year Plan (6/03) NSTX Research Forum (11/03) PAC-15 (1/04) • Plan – 18 run weeks in FY 04 3 SMK – PAC 15 3

Run Plan Addresses Milestones By Exploring Fundamental ST Physics • Highest level milestone (FY 04 -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 (T&T, MHD, ISD) 4 SMK – PAC 15 4

Many Topical Areas Have Specific Milestones • T&T (FY 04 -2) – Measure long-wavelength turbulence in ST plasmas in a range of plasma conditions • HHFW/EBW, T&T (FY 04 -3) – Measure plasma current profile modifications produced by RF, NBI and p techniques • Solenoid-free startup (FY 04 -4) – Conduct initial tests combining available techniques to achieve solenoid-free initiation to substantial currents • HHFW/EBW (FY 04 -5) – Measure EBW emissions to assess heating and current drive requirements 5 SMK – PAC 15 5

Run time allocations for FY 04 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 6 SMK – PAC 15 6

Heating and Current Drive (HHFW/EBW) • Two FY 04 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. FY 04 – MSE (3 10 channels) – HHFW antenna modified to increase voltage/power limit (FY 03) – CURRAY integrated into TRANSP – Increased use of CURRAY, CQL 3 D, AORSA 1 D for discharge scenario development (also in ISD) 7 SMK – PAC 15 7

HHFW FY 04 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 Hot Component – Dependence on power, density, temperature and phasing – Measure j with MSE Cold Component • HHFW-only H-mode – SN, DN target development • HHFW + NBI: important for Five Year objectives – High-bt or high-Te (RS) NBI target 8 SMK – PAC 15 8

EBW FY 04 Research Plan • FY 2004 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 9 SMK – PAC 15 9

Solenoid-Free Startup • Milestone FY 04 -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-FY 04) New ceramic insulator (FY 03) EFIT with open field line current 3 D modeling of resistive linear and non-linear stability – PF-only startup • PF 4 power supplies for “outer PF” startup (mid-FY 04) • HHFW to assist plasma formation • DINA calculations (resistive MHD and transport) for scenario and control system development 10 SMK – PAC 15 10

CHI FY 04 Research Plan • Employ transient CHI scenario – Continue FY 03 exp’ts but with cap bank for rapid rate of rise of injector current – Build on development made in HIT-II – PF 3 L 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 11 SMK – PAC 15 11

PF-Only Startup FY 04 Research Plan • Outer PF startup – additional discharge scenario development required (TSC, DINA) – Bipolar BV swing (no field null) • HHFW/ECH plasma source 20 k. A - 20 k. A – Outboard null • No PF 4: 100 k. A • PF 4: 100’s k. A – HHFW assist 2. 8 k. A • Initiate plasma on outboard side • Drive 50 -100 k. A with PF ramping • Use HHFW to heat and drive current further • HHFW rampup – Clamp OH current after Ip=50 -100 k. A – Apply HHFW to heat and drive current 12 SMK – PAC 15 12

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 (FY 03) EFIT with rotation, expanded data input; FLOW MARS SMK – PAC 15 13 13

Shape and Rotation Influence Strongly Plasma Stability • b. N up to 6 achieved at high elongation • FY 04 Research Plan - High-b. N – High-b. T @ 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 highn stability (need PF 4) 14 SMK – PAC 15 14

Shape & Rotation – FY 04 Research Plan (cont’d) 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 15 SMK – PAC 15 15

Additional MHD Studies • Fast ion MHD – Parametric dependence of fast ion losses on Ip, BT, q 0 • TAE, CAE, GAE – Suppression of frequency “chirping” in fishbone instabilities • Non-linear mechanism • Similarity exp’t with DIII-D (chirping observed on NSTX but not on DIII-D) • Neoclassical Tearing Mode Onset – b-scan • ELM stability vs shaping (piggyback) 16 SMK – PAC 15 16

Transport and Turbulence • FY 04 -1 – Assess confinement and stability in NSTX by characterizing high confinement regimes with edge barriers and ……. • FY 04 -2 – Measure long-wavelength turbulence in ST plasmas in a range of plasma conditions • FY 04 -3 – Measure plasma current profile modifications produced by … p techniques • Related research topics – Establish t. E and transport scalings – Study electron transport physics – Determine influence of Er (w. Ex. B) and b. T on turbulence, transport, L-H transitions and pedestals 17 SMK – PAC 15 17

Transport and Turbulence • New capabilities in 2004 – – – – MSE 51 channel CHERS (FY 03) Scanning NPA (FY 03) Edge Rotation Diagnostic (FY 03) - 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 18 SMK – PAC 15 18

Parametric Scaling Trends Have Been Studied t. ENSTX-L ~ Ip 0. 76 BT 0. 27 PL-0. 76 • L-mode scaling presented to PAC 13 (10/02) and PAC 14 (1/03) • Non-linear H-mode power dependence – Ip, BT, etc parameter ranges too limited to perform meaningful scaling 19 SMK – PAC 15 19

t. E and Transport Scalings – FY 04 Research Plan • Systematic H-mode and ITB studies in quasi-steady discharges – DND to connect to international database – NSTX/MAST identity exp’ts 2 x 1 x • ITPA high priority 0. 5 x • NSTX/DIII-D similarity – R/a effects at fixed bpol, r*pol • Dimensionless scalings within NSTX – OH/NBI R/a – Initial n*, b. T (ITPA high priority) c-scalings will also be developed from the results of these XPs 20 SMK – PAC 15 20

t. E and Transport Scalings – FY 04 Research Plan (cont’d) • 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) 21 SMK – PAC 15 21

Electrons Dominate Transport Loss · Large uncertainties in c’s in center and near edge due to data/equilibrium uncertainties · 51 point CHERS should help resolve some uncertainties - Better defined gradients 22 SMK – PAC 15 22

Local Transport – FY 04 Research Plan (cont’d) • 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 GS 2 Calculations • Comparison of NBI vs HHFW transport – Vary fractions of simultaneous NBI, HHFW power • Need to develop successful synergistic scenario – Momentum transport studies SMK – PAC 15 23 23

Core and Edge Turbulence – FY 04 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) FIRETIP Reflectometry Accessibility • Combined edge turbulence study – GPI: higher spatial/temporal extent, resolution – Recip. probe: multiple tips to resolve Te, ne and Er, Epol, B, Te, fluctuations 24 – w/Boundary ET SMK – PAC 15 24

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 T&T) • New capabilities in 2004 – – – Low-Z pellet injector (Li/B/C) Supersonic gas injector Improved boronization schemes Upgraded reciprocating probe Edge rotation diagnostic (FY 03) SMK – PAC 15 25 25

Fueling and Particle Control – FY 04 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 SMK – PAC 15 26 26

Power and Particle Control – FY 04 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 27 SMK – PAC 15 27

Integrated Scenario Development • Highest level milestone requires integration of techniques to produce high performance plasmas – Simultaneous high-bt, t. E for long duration (t. FT >> t. E) – NBI/HHFW compatibility New System (< 1 msec) Data Bits • New capabilities in 2004 – Control system upgrades – – • Decreased latency HHFW loading, outer gap control GA rt. EFIT shape control (continuing) Improved wall conditioning Improved gas injection/density control Original System (~ 3 msec) Time (msec) 28 SMK – PAC 15 28

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, t. E • 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 (f. BS ~ 0. 40 previously) SMK – PAC 15 29 29

ISD 2004 Research Plan (cont’d) • HHFW/NBI compatibility desirable for attaining ultimate target objectives – Couple HHFW into high-b. T 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 longpulse operation 30 SMK – PAC 15 30

FY 04 Research Aimed Towards Early Development of High-Performance Plasmas Early Run H&CD HHFW conditioning - Decay HHFW Power Deposition Thermal Ion Htg, CD, H-mode Startup CHI into inductive HHFW startup Mid-Run Late Run B-X-O, B-X EBW HHFWCD w/j(r) measurements HHFW + NBI HHFW Htg Efficiency/Ponderomotive Effects Transient CHI Solenoid-free startup with PF 4 Absorber null assessment MHD High-bt at high k High-bpol aspect ratio effects RWM passive stabilization Collective fast ion loss NSTX/DIII-D RWM similarity RWM dissipation, rotation damping Neoclassical Tearing Modes Stability studies with j(r) meas. Effect of boundary on high-n Suppression of fishbone chirping Active EF/RWM control T&T NSTX/MAST L-H Fast ion profile NSTX/MAST H-mode scaling Core, edge turbulence PNBI vs PHHFW transport Electron ITBs (RS) Intra-machine R/a scaling NSTX/DIII-D similarity Dimensionless scaling in H-mode NSTX/MAST/DIII-D pedestal Momentum transport Bdy SS Gas Injector Boronization schemes Density control Edge turbulence Detached divertor Boundary characterization Li particle control, Low-z pellets ISD Control system development High-k LSN, DN HHFW/NBI compatibility SMK – PAC 15 H-mode during I ramp Long-pulse HHFW H-mode Fueling during long-pulse H-modes 31 USN w/ Reversed BT 31

A Collaborative Control Room Will Aid Run Productivity Similar to the PPPL display wall room A productive collaboration among PU/PPPL/NSTX 32 SMK – PAC 15 32

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 33 SMK – PAC 15 33

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ci ci, neo near core 35 SMK – PAC 15 35