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1 E.J. Synakowski PPPL For the NSTX National Team For the NSTX Program Advisory Committee January 12, 2004 Highlights of the NSTX Five Year Plan and Recent.

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Presentation on theme: "1 E.J. Synakowski PPPL For the NSTX National Team For the NSTX Program Advisory Committee January 12, 2004 Highlights of the NSTX Five Year Plan and Recent."— Presentation transcript:

1 1 E.J. Synakowski PPPL For the NSTX National Team For the NSTX Program Advisory Committee January 12, 2004 Highlights of the NSTX Five Year Plan and Recent Adjustments 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

2 2 The NSTX Team is excited about getting on with new experiments The starting line –results from ‘02 and early ‘03 campaign generated excitement about what this program can accomplish Where we are going –We developed a Five Year Plan that challenges us, sharpens the vision of what it means to create the physics basis for the ST, and contributes to areas of importance to toroidal confinement physics

3 3 The research plan in ‘04 is the first step toward meeting the 5 Year Plan goals The FY ‘04 plan has a balanced and aggressive approach with respect to facility upgrades and diagnostics The research plan explores physics that can be best revealed on the ST in striving towards major milestones To accommodate budget realities, increased collaborations are being pursued, and some investments are being deferred Peng Ono

4 4 In this talk… Five Year Plan: brief reprise of the approach Zoom in: Topical Research Plans for 2004, in the context of the 5YP –MHD –Transport –Wave-particle physics & startup –Boundary physics –Integration For each topic: –near-term milestones –relation of near-term research to goals for the out years –adjustments to the 5YP assuming flat budgets –responses to the 5YP review committee comments & concerns

5 5 NSTX is poised to assess the attractiveness of the ST as a fusion energy concept Extend knowledge base of plasma science Establish physics basis & tools for high performance for ∆t >> t skin Develop control strategies for toroidal systems Use high  & low A to deepen understanding through measurement, theory, & collaboration Physics exploration and passive limits - Identify needed control tools Optimization & integration high  T and J BS near with-wall limit for ∆  >>  skin ‘02 ‘03 ‘04 ‘07 ‘08 ‘09 ‘05 ‘06 Advanced control & high  physics high  T &  E, ∆t >  E high  N &  E, ∆t >>  E establish solenoid-free physics & tools 5 Year Plan developed assuming 1.1 x Presidential budget

6 6 Solenoid- free  T = 30   HH = 1  N = 5: > no wall limit ∆t pulse >  E I NI > 60%, ∆t pulse ~  skin Non-solenoid startup demo Highest performance  T = 40% ∆t pulse >>  skin  with wall limit HH = 1.5 I NI ~ 100%  T = 40%, HH = 1.2, ∆t pulse >  E   N ~ 8, ~ with-wall limit, ∆t pulse >>  E I NI ~ 100%, ∆t pulse >  skin Solenoid-free ramp to hi  p Integrating topical science is central to advancing the NSTX mission FY Integration Boundary & fueling Wave-particle interactions Transport Macrostability at low A and large V  /V A Turbulence & stabilization at low A and high . Electromagnetic effects at low & high k MHD Wave-particle interactions in overdense plasmas Edge physics with large B p /B T. Advanced plasma-surface interactions

7 7 The research plan has been modified in response to less optimistic budgets In developing the 5 year plan, a budget 10% larger than the FY ‘04 presidential request was assumed Here, for FY ‘04, assume 500 k less than the presidential request. For ‘05 and ‘06, assume a flat budget at the FY ‘04 presidential request, with no inflation This has an impact on run weeks as well as upgrades –18/18/15 run weeks for 04/05/06

8 8 Tools were identified for achieving the desired goals targets Operating scenarios were developed for meeting the goals Research plans were developed to make the most of the science accessible in the new operating regimes A long-range goal is operation near the with-wall limit at low internal inductance Control tools are central elements to developing robust path to high performance, long pulse targets EFIT  Wall- stabilized Long pulse integration goal In the planning process:

9 9 40%  T, 100% I NI,  pulse >>  skin is a major target at the end of the 5 Year Plan and will require new tools Enhanced shaping improves ballooning stability through simultaneous high  and  Near with-wall & ballooning limits  mode control + rotation are key EBW provides off-axis CD to keep q > 2 Particle control required to maintain moderate n e for CD HHFW heating contributes to bootstrap, raises T e Kessel

10 10 MHD Transport and Turbulence Wave-particle physics & startup Boundary physics Integration “The panel members commended the NSTX team for the remarkable progress in the stability area… They commented that MHD is an area where there has been strong and successful participation by collaborators…”

11 11 MHD physics RWM, V , & wall NTM suppression  limits & V   shear  limiting modes vs. shape, li, P Fast ion modes RWM mode suppression Internal mode characterize FY Optimize stability in long-pulse high beta regimes Milestone FY05-1: Produce and characterize ST plasmas near the wall-stabilized limits (September ‘05) Discussed next… MHD physics opportunities Distinguish V A, C s effects for rotation damping V  /V A  1 => V  ’ ~  lin MHD

12 12 Target this year This year:  = 2.4,  = 0.6, I p > 1.5 MA a target Identified in 5 Year planning: future split, shift of PF1A should enable  = 2.7,  = 0.9 Recent control improvements may allow increase in beta

T T  B T 0 2 /2  0  T = 35% EE FY ‘02: B T = 0.3T, A = 1.4  = 2.0,  = 0.8 q(0) = 1.4 (EFIT) H mode Gates

13 13 Diagnostics installed for more detailed mode characterization, aiming for feedback Process sensor data in real- time through plasma control system for feedback control experiments in ‘05 24 each large-area internal B R, B Z coils installed before ‘03 run –Mounted on passive stabilizers –Resolve up to n = 3 B r sensor Sontag, Bialek (Columbia) Menard Internal RWM/EF sensors BRBR BZBZ

14 14 External correction coil is designed and plan is to install it by summer PF5 coils (main vertical field) Operate as 3 opposing pairs –Counteract error field amplification –Low (error correction) or high frequency High frequency power supplies being purchased Vigorous use in ‘05, aiming for with-wall limit milestone Columbia U. “…the panel members commented that rapid implementation of external coils to investigate [active mode stabilization] will be important.”

15 15 Joint machine experiments are part of the plan for assessing RWM physics With DIII-D Similar sound speed, different Alfvén speeds on two devices allow discrimination of mode damping mechanisms Contributes to ITPA Sontag, Reimerdes, Sabbagh, Garofalo

16 16 Effects of high V  /V A seen in equilibria, and relevance to stability is being explored Experiment: Density shows in- out asymmetry Effect of high Mach number of driven flow Menard, Park, LeBlanc Experiment: kinks saturate Stutman (JHU) M A = Time M A = 0 Theory: for fixed momentum input, growth rate reduced by factor of Measured (MPTS) (assuming density is a flux function) (with centrifugal effects)

17 17 Plasma flows now included in NSTX EFIT reconstructions Use T i, Z eff profiles, and fit to plasma toroidal rotation Full rotation solution fitting total and dynamic plasma pressure at (R, Z=0) Change in stored energy with/without V  = +/- 3% Significant drop in  mag 2 and  p 2 even though 50% more P channels and smaller error bars R(m) Z(m) Poloidal flux and pressure Pressure iso-surfaces clearly shift outward from flux surfaces when rotation is high Black - flux surfaces White - constant pressure surfaces Sabbagh (Columbia)

18 18 MHD Transport and turbulence Wave-particle physics & startup Boundary physics Integration “Overall, the panel members felt the primary areas of challenge for (NSTX research for) the next 5 years will include transport (particularly electron transport)”

19 19 Transport & turbulence Transport physics Global s  L       high electron & ion heating, V  high and low k turbulence vs.     and maximizing P, J BS, J NBI FY Optimize P, J BS, J NBI Understand: turbulence/theory comparisons Milestone FY04-2: Measure long wavelength turbulence in a range of plasma conditions - from the edge into the confinement region Milestone FY05-2: Measure high k turbulence New FY07 milestone proposed: Measure low k turbulence with imaging reflectometry Turbulence physics opportunities Low k with NBI: intrinsically stable? Low and high k may be controllable with NBI & HHFW.

20 20 Improved diagnostic capability will aid in transport studies CHERS: resolution approaches impurity gyroradius in the edge R. Bell

21 21 Propagating the experimental uncertainties through the power balance analysis has increased confidence in analysis in core Propagated kinetic profile variations through power balance analysis LeBlanc, Kaye High  p, LSN

22 22 Edge turbulence measurement capability improved New fast camera: 300 frames, 250 kHz –Catch L-H transitions, ELMs 10x more light with improved optics, wider field DEGAS-2 analysis quantifying relation between fluctuating emission and plasma quantities BOUT analysis enables detailed comparison with turbulence theory Also, reciprocating edge probe will be used (Boedo, UCSD) Lowrance, Maqueda, Zweben

23 23 Core turbulence to be measured by correlation reflectometry Correlation reflectometry system upgraded to access n e = 2x10 13 cm -3 Particle control improvements via Li pellets may help by reducing density L modes the likely targets (modest peaking of n e ) Gilmore (UNM), Kubota, Peebles (UCLA) This is the primary tool for core measurements addressing the low k milestone in FY ‘04

24 24 Development of high k scattering capability aims for FY’05 measurements Initial system will allow high k measurements in select locations (up to 30 cm -1 ) Available for ‘05 run Backscattering also being investigated (Peebles, UCLA) High k scattering Luhmann (UC Davis), Mazzucato, Munsat, Park, Smith (Princeton U.) “…there is a good opportunity to study…short wavelength (ETG) modes, which would be a major contribution to the physics of tokamak turbulence.”

25 25 For the transport studies, there is an impact of running at a lower budget than assumed in the Five Year plan start early ‘05 deploy in ‘06 ‘04/’05/’06 (30 ch/90 Hz/40 ch) The plan is to meet the transport and turbulence milestones for ‘04 and ‘05. A new imaging milestone is proposed for ‘07. start early ‘05 deploy in ‘07 ‘05/’06/’07 High k scattering system Low k imaging Thomson upgrades 5 year planFlat budget, ‘04 - ‘06 (1.1 x presidential)

26 26 MHD Transport and Turbulence Wave-particle physics & startup Boundary physics Integration “The review panel members concluded that non-inductive current drive is very important for PoP tests on NSTX.”

27 27 Wave-particle & startup Non-inductive startup development FY EBW emissions & coupling CHI +ohmic CHI+PF CHI+HHFW CHI +HHFW+NBI to high  p Optimize EBW startup assist CHI toroidal current CHI long pulse feedback control Higher I p : NB CD + bootstrap Mid-I p HHFW CD +bootstrap,PF PF induction OH-solenoid-free research HHFW heating & phasing Milestone FY 04-3: Measure plasma current profile modifications produced by radiofrequency, neutral beam injection, and pressure-gradient techniques. (September 2004) Milestone FY 04-4: Conduct initial tests combining available techniques to achieve solenoid- free initiation to substantial plasma currents. (September 2004) Milestone FY 04-5: Measure Electron Bernstein Wave (EBW) emissions to assess heating and current drive requirements. (September 2004) Wave-particle and startup opportunities HHFW, EBW: new physics & tools for overdense plasmas (for ST, RFP) OH-solenoid-free plasma startup research addressing urgent issue for AT & ST.

28 28 HIT-II JT-60U Experiment on HHFW CD following brief ohmic start is planned this run. Also outer PF induction studies are planned CHI + Induction New capacitor bank to be installed this year (May). CHI + induction planned for this run Approach on startup physics is being broadened, based in part on recent studies elsewhere Transient CHI.5 Injector current Plasma current CHI only Time (ms) Plasma current Injector current Raman Takase

29 29 Plan approaches solenoid-free startup research with different tasks Startup: kA –CHI, outer PF induction the primary tools at present –New experiments planned, new scenarios being assessed Initial rampup: kA –HHFW, EBW, bootstrap –Can study with an ohmic start Final ramp to flattop – kA: NBI CD, bootstrap current overdrive are candidates Flux contours 20 kA - 20 kA 2.8 kA New element for FY ‘04: field null capability with outer PF coils (April) “…the panel… felt that it is important to investigate additional approaches to non-solenoidal startup… The schemes for poloidal field ramp-up outlined by the NSTX team should be tested… as soon as feasible.”

30 30 HHFW current drive research will include studies of different phasings V loop changes observed last year, but most experiments were run at 7.6 m -1 Modeling indicates 3 m -1 should drive more current (AORSA; Jaeger/CURRAY; Mau) Experiments planned for phase-dependence studies Time (s) volts co-CD ctr-CD Ryan, ORNL 1234 n e (0) (x10 13 m -3 ) A/W

31 31 The importance of understanding ion absorption of HHFW was revealed in experiment and modeling Edge spectral measurements reveal hot ions at edge, high rotation velocities –Theory suggests parametric decay (Wilson) In modeling: HHFW absorption from hot thermal ions as well as beam ions found –Potentially large impact on current drive. Biewer

32 32 Ideally suited for the ST –Takes advantage of high particle trapping (Bers (MIT): Ohkawa CD) –Efficiency increases with minor radius, where it is needed most Off-axis CD required to elevate q & stabilize NTMs. Successful coupling essential –CDX-U & NSTX EBW emission studies are consistent with theory. Developing the science of Electron Bernstein Wave heating and CD is a key element of the plan 28%  T 100% I NI scenario CQL3D EBWCD Efficiency (kA/MW) Peak Current Density (A/cm 2 ) Location of Peak EBWCD Density r/a 2 -2 Launched n // Harvey, CompX Minor radius (m) n = -2 n = 2 Local current density, HFS midplane Bootstrap q J (A/cm 2 ) Fisch-Boozer Ohkawa 1 MW EBW in plasma

33 33 Obtaining > 80% EBW conversion efficiency will be pursued with dedicated antenna and limiter combinations For both B-X and B-X-O emission conversion Similar antenna achieved ~ 100% coupling on CDX-U Modeling indicates that O-X-B launch is resilient to changes in edge n e Taylor

34 34 To obtain knowledge of internal magnetic field, initial MSE CIF system will be joined by x-ray imaging MSE: 10 channels planned by end of run –Run time will be dedicated for calibration X-ray imaging also being developed to constrain equilibria Imaged area Pacella (Frascati-JHU), Tritz (JHU), Kaita, Stratton Micro- patterned gas detectors

35 35 The 5 YP panel saw EBW as a needed investment, but worried about cost and schedule Response of the NSTX team: Enhanced collaborations with MAST on 28 GHz EBW work in (O mode accessibility with reflection from center-stack). Discussing with MAST our development of a launcher for experiments on their device (O-X-B conversion), to inform the NSTX tube and launcher development Regarding EBW, the “panel recognized that this… is speculative, but concluded that the experiments are important and should be pursued aggressively. They cautioned that development of high power tubes [near 15 GHz] will… take a long time, and can be expensive… [T]hus, any alternatives to allow for earlier experiments, if they exist, should be considered in order to validate predictions.

36 36 The EBW approach has been modified to enable gains from collaboration EBW design and fabricate prototype 1 MW, to be available in ‘06 5 year planFlat budget, ‘04 - ‘06 (1.1 x presidential) Perform in ‘04 - ‘05. Test 1 MW prototype in ‘06 FY ‘04 emission studies, as planned. Develop design of 28 GHz launcher (likely O-X-B, deliver in ‘05, use in ‘06) FY ‘06: begin developing 1 MW tube, to be deployed in ‘08 The plan is to meet the ‘04 and ‘05 milestones as scheduled. Deployment of EBW at the 1 MW level on NSTX will be delayed by 2 years.

37 37 MHD Transport and Turbulence Wave-particle physics & startup Boundary physics Integration “The panel felt that the focus on particle control is necessary to optimize non- inductive CD and that lithium surface conditioning appears to be a cost-effective way to reduce recycling.”

38 38 Boundary physics Boundary physics, power handling, & fueling Liquid Li divertor? FY Milestone FY05-4: Characterize plasma edge pedestals and scrape-off layer fluxes in high performance ST plasmas Power balance, heat flux scaling Fueling studies Transient event studies Pedestal and ELM characterization Edge Optimization Studies Detachment studies Li, B pellets Li coatings Particle, heat flux control studies PFC upgrade ?

39 39 An array of diagnostics will allow the FY ‘05 milestone on pedestal and edge flux characterization to be met Present diagnostics allowing determination of particle and heat fluxes Additional 10 channels of Thomson scattering, some to be deployed for edge measurements for FY ‘05 T i and V  resolution on the scale of  carbon Diagnostics include: edge D  and impurity spectroscopy, reflectometry, edge turbulence imaging and edge probe, fixed divertor probes, divertor bolometer, infrared camera Viewing locations for 1D CCDs for D  spectroscopy Ion flux DD

40 40 A new impurity pellet injector is poised for action this run To be commissioned in the coming weeks. This is the first phase in a plan to assess physics and value of lithium coatings, leading to a liquid lithium module decision after FY ‘06 A near-term tool for density control –Also hot boronization & supersonic gas injection

41 41 Installation of e-beam evaporator for Li deposition planned for ‘05, providing info for a decision on a liquid Li module in ‘06 Li coatings: localized, 1000 Å before every shot e-beam for Li coatings Liquid lithium module Under ALIST group of VLT Potential solution for both power and particle handling

42 42 Flat budgets imply relying on lithium coatings in the near term for particle control Install lithium pellet injector/ lithium coating system Liquid lithium module Divertor/Fast IR Cameras Design and install cryopump and D pellet injector Divertor PFC upgrade Divertor MPTS FY ‘04/05 Decide at end of ‘06 FY ‘04/05 Design and install for ‘06 run install in ‘07 FY ‘07 FY ‘04/05 Decide at end of ‘06 FY ‘04/05 Incremental budget - deferred delay 1 year Incremental budget - deferred 5 year planFlat budget, ‘04 - ‘06 (1.1 x presidential)

43 43 Integration MHD Transport and Turbulence Wave-particle physics & startup Boundary physics Integration Milestone FY04-1: Assess confinement and stability 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. Milestone FY 05-3: Demonstrate full non-inductive current via combinations of radiofrequency wave, neutral beam injection, and pressure-gradient driven currents. Milestone FY Explore scenarios for combining neutral beam injection and radiofrequency heating and current drive to achieve high plasma pressure and high energy containment efficiency for time scales much larger than the energy replacement times

44 44 Solenoid-free ramp to high  p : essential to any ST- or AT-based reactor concept (discussed earlier) Transient high toroidal beta Non-inductively sustained, CTF-relevant beta,  pulse >>  skin –HHFW heating + NBI heating and CD, 0.5 T, 800 kA –HHFW + EBW, both heating and CD, 875 kA Integration: 40%  T, non-inductive,  pulse >>  skin By mid-plan:  By end of the plan:  Integration Solenoid- free  T = 30   HH = 1  N = 5: > no wall limit ∆t >  E I NI > 60%, ∆t ~  skin Non-solenoid startup demo Highest performance  T = 40% ∆t pulse >>  skin  with wall limit HH = 1.5 I NI ~ 100%  T = 40%, HH = 1.2, ∆t pulse >  E   N ~ 8, ~ with-wall limit, ∆t pulse >>  E I NI ~ 100%, ∆t >  skin Solenoid-free ramp to hi  p Integration of the science in the 5 Year Plan

45 45 Experimental long pulse results form the basis for future integration work J NI = 60%  N = 5.8 > no-wall stability limit Many parameters that are relevant to a CTF So far, NBI only - no HHFW. NSTX Long pulse CTF base case ARIES- ST TT 15%20%50%+ NN 558 pp q cyl  skin

46 46 Effectiveness of HHFW + NBI will be studied in earnest this run Understanding of this is key to the program and integration goals. –coupling and compatibility with the H mode are two issues –Supplemented by HHFW & NBI studies in Transport and Integrated Scenario groups IF this proves to be hard, time will be dedicated to understanding why 800 kA, 5 kG, 18%  T P NBI = 4 MW, P HHFW = 6 MW  = 2.7,  = 0.9 Mid-plan: non-inductively sustained 100% J NI scenario (HHFW heating + NBI heating & CD only)

47 47 This run, research on integrated scenarios is focusing on the components needed for our 5 Year Plan goals Early HHFW heating Early H mode Upgraded control capability - reduced latency rt-EFIT Measure control system responses for simultaneous high  and  Shape development Li pellets for particle density control NBI + HHFW scenario development

48 48 Some hardware changes for enhanced stability are on track, others are delayed Control computer & handshake upgrades PF 1A split & shift Passive stabilizer modification ‘04, ‘05 Implement in ‘05, use in ‘06 Design and install in ‘05, use in ‘06 On track Delay by 1 year Delay by 1 year; incremental budget 5 year planFlat budget, ‘04 - ‘06 (1.1 x presidential)

49 49 The FY ‘04 run will take important strides in meeting the 5 year goals MHD Transport & turbulence Wave-particle/startup Boundary physics Integration RWM: active coil install and deployment, damping physics (with DIII-D), passive stablization High  p equilibrium limits fast ion MHD NTM Long-wavelength turbulence, core and edge Edge fueling and H mode Aspect ratio and pedestals (w/ MAST, DIII-D) Aspect ratio and core transport (w/ DIII-D) Electron thermal barriers and reverse shear EBW emissions and EBW collaboration (MAST) HHFW CD and role of phasing HHFW deposition Transient CHI. PF induction. HHFW-only rampup Li conditioning SOL transport & turbulence Heat and particle flux scaling Improved shape development (w/ DIII-D; rtEFIT) Vertical control Vertical stability with long-pulse high current HHFW heating with NBI HHFW CD with hot ions Startup optimization with HHFW Details of run in talk by Kaye

50 50 The NSTX Team is following a balanced and aggressive research plan Experimental and analysis capability has grown since we last operated, positioning us for an exciting run Generating the Five Year Plan sharpened our vision for developing the necessary tools for our research, and for studying important toroidal confinement science If budget funding is flat, there will be deferred investment in the needed research tools, and delay in meeting the goals.

51 51

52 52

53 53 Proposed FY04-06 research milestones aim to make progress in high , transport, startup, current drive, boundary & integration 1) What causes plasma turbulence & transport? Measure low-kMeasure hi-kImage low-k turbulenceturbulenceturbulence 2) How are plasma pressure & bootstrap current limited? Assess plasma & Study plasmas nearIdentify NTM rotation interactions“with-wall” limitonset conditions 4) How to convert externally directed energies to plasma magnetic flux? Extend & analyzeTest currentSolenoid-free ramp- sustainment to 1sinitiationup to high  p 5) How do plasmas interact with materials? Analyze edge Characterize edgeAssess long-pulse heat fluxesof H-mode plasmasheat & particle control 6) How to integrate ST plasma science into attractive sustained burning plasmas? Characterize high Assess hi  E & hi  T Assess combinedDemonstrate J NI  T &  E for >  E H-mode for >>  E RF & NBI effectiveness~ 100% for >>  skin 3) How do energetic particles & RF power sustain plasmas? Characterize EBW Measure  J fromDemonstrate emission, est. H&CD RF, NBI &  pJ NI ~ 100% for ≥  skin Exp. Runwks: 4 FY03FY04FY07FY06FY Fixed TFC 18 Characterize EBW emission, est. H&CD

54 54 Transport barrier assessments are in progress and are motivating experiments in FY ‘04 R. Bell, B. LeBlanc ms 290 ms 270 ms 250 ms 230 ms (~H-mode transition) Plasma Edge Peng, R. Bell T i and V  gradients expand towards edge after H mode transition Power balance reveals propagating drop in  i with steep gradient Reduced electron thermal barriers found with reverse shear (Stutman) This run: experiments on electron thermal barriers and the role of reverse shear will be performed

55 55 Behavior of electron and ion thermal transport with combined HHFW and NBI will be assessed in FY ‘04 An understanding of  i and  e with both heating schemes is one step needed to further assess the requirements for meeting the Five Year Plan goals  Experiments with admixtures of NBI and HHFW are planned this run

56 56 Edge rotation diagnostic allowing for determination of edge E r HHFW yields more negative-going E r, consistent with ion loss Will be used in H mode studies Biewer, Bell

57 57 The major thrusts of the proposed 5 year program were endorsed by the review panel “The panel members generally agreed that the proposed NSTX program would make important contributions to fusion research, both within the US and worldwide…(and) is clearly addressing the goals of the US fusion program... The NSTX team has identified the outstanding scientific issues for the ST… and has made plans to address them. …Overall, the panel members felt the primary areas of challenge for the next 5 years will include transport (particularly electron transport) and the scientific basis for non-inductive current sustainment, profile control, and startup without the use of the central solenoid.”

58 58 Neoclassical tearing mode stabilization is part of the motivation for an EBW system For NTM stabilization, MW delivered to the plasma is needed to replace the bootstrap current (3 MW delivered needed for bulk CD) Benefits from high particle trapping in ST (Ohkawa current drive) Further NTM experiments planned in FY ‘04 Development plan, milestones described later in talk 28%  T 100% I NI scenario Minor radius (m) n=-2 n=2 Local current density, HFS midplane Bootstrap q J (A/cm 2 ) 1 MW EBW in plasma Fisch-Boozer Ohkawa Harvey, CompX

59 59 Unique physics opportunities were clarified in the planning process MHD Distinguish V A, C s effects for rotation damping V  /V A  1 => V  ’ ~  lin MHD Turbulence Low k with NBI: intrinsically stable? Low and high k may be controllable with NBI & HHFW. Wave-particle physics and startup HHFW, EBW: new physics & tools for overdense plasmas OH-solenoid-free plasma startup research addressing urgent issue for AT & ST. Boundary physics Liquid lithium: develop for potentially revolutionary boundary solutions

60 60 Modeling indicates that HHFW & bootstrap can be used following CHI or PF induction to raise the current to several hundred kA Modeling indicates direct CD and J BS from HHFW can ramp to 400 kA within the allowable pulse at high field Modeling not fully optimized –No EBW assumed kA 0123 Time (s)

61 61 Boundary & fueling HHFW/ EBW/ CHI Transport MHD Heating, CD demo Solenoid-free ops Optimize V-s in highest performance Heat flux scalings Particle control, no pump Advanced particle & heat flux control Passive limits with rotationActive controlOptimize stability Optimize P, J BS, J NBI Understand: turbulence/theory comparisions Characterize IPPA: attractiveness stability and high beta,  >>  E IPPA: extrapolable,   >>  skin, high performance Integration Solenoid- free  T = 30   HH = 1  N = 5: > no wall limit ∆t pulse >  E I NI > 60%, ∆t pulse ~  skin Non-solenoid startup demo Highest performance  T = 40% ∆t pulse >>  skin  with wall limit HH = 1.5 I NI ~ 100%  T = 40%, HH = 1.2, ∆t pulse >  E   N ~ 8, ~ with-wall limit, ∆t pulse >>  E I NI ~ 100%, ∆t pulse >  skin Solenoid-free ramp to hi  p Integrating topical science & control tools is central to advancing the NSTX mission FY

62 62 NSTX is poised to assess the attractiveness of the ST as a fusion energy concept plasma science Physics exploration and passive limits - Identify needed control tools Optimization & integration high  T and J BS near with-wall limit for ∆  >>  skin ‘02 ‘03 ‘04 ‘07 ‘08 ‘09 IPPA 10 year ‘05 ‘06 IPPA 5 year Advanced control & high  physics high  T &  E, ∆t >  E high  N &  E, ∆t >>  E establish solenoid-free physics & tools Challenge limits of plasma science Understand physics of high beta plasmas Enhance predictive capability Advance control strategies Extend knowledge base of plasma science Physics basis & tools for high performance for ∆t >> t skin 5 Year Plan developed assuming 1.1 x Presidential budget


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