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Alcator C-ModHighlights, Plans, Budget and Schedule
OFES Budget Planning MeetingMarch 15, 2005
E. S. Marmarfor the Alcator Group
IPPA 3.1, 3.2, 3.3 IPPA 3.2, 3.3
IPPA 1.1, 3.1, 3.2, 3.3 IPPA 1.4, 3.2, 3.3, 4.1, 4.4 IPPA 1.3, 3.1, 3.2, 3.3, 4.1 IPPA 1.2, 3.2, 3.3, 4.1
Research Highlights 2004
• SOL flows impose a toroidal rotation boundary condition for confined plasma*– Explanation for large flows seen
to drive D/T co-deposition– Explanation for topology
dependence of H-Mode threshold
• External control coils used to study and suppress intrinsic error fields†
– Important scalings for ITER– Allowed first operation to Ip=2.0
MA
*LaBombard, APS and EPS invited talks†Wolfe, APS invited talk
Research Highlights 2004 (cont’d)
• ITB control with 2-frequency ICRF – Picture of control mechanisms emerging from fluctuation measurements and non-linear GS2 simulations*
• ICRF fast wave and mode conversion – Fast, Bernstein and IC waves all observed experimentally (PCI); Modeled with TORIC†
– Important code benchmarks– Demonstrated Ip drive– Flow drive not yet definitive
• Mode seen with PCI– k and ν agree with GS2
simulation (TEM drives outward particle transport, balancing pinch)
Wav
enum
ber(
cm-1
)
Time (s)
*Ernst, IAEA†Wukitch, APS invited talk
Research Highlights 2004 (cont’d)
• Improved edge turbulence measurements (300 frame, 250 kHz movies, fast diodes, probes)*– Collaborative turbulence modeling
[Risø†, LLNL (BOUT)‡]• Risø model predicts blob formation and
strong radial propagation, similar to experiment
• Active and ICRF fast-particle driven Alfvencascades– Important ITER physics– q-profile diagnostic during ramp-up– Snipes, APS invited talk– Strong modeling collabs with
Gorelenkov, Kramer, Breizman, Zonca
*Grulke, APS invited talk†O.E. Garcia, V. Naulin, A. Nielsen, J.J. Rasmussen‡M. Umansky, T. Rognlien, R. Cohen
Comparison of Experiment and Risø Model for edge turbulence PDF statistics
Log 1
0(P
DF)
Log 1
0(P
DF)
(n-n)/nrms
(n-n)/nrms
2 MA Operation Made Possible byField Error Correction Coils
• Prior to installation of asymmetric control coils, locked modes prevented operation above 1.6 MA
• Nulling out principal component of error field enabled operation to 2 MA– These discharges have
low normalized density (n/nG ~ 0.17) very similar to ITER ohmictarget
Budget Profiles (k$)
18,977(0)
90
374
1,702
16,801
FY07D
28,755(25)
120
480
2,250
25,905
FY07B
22,038(17)
100
415
2,052
19,471
FY05
22,183(12)
21,530(12)
National Project Total(research run weeks)
100100LANL
415415U Texas
2,0022,002PPPL
19,66619,013MIT
FY07AFY06Institution
Appropriation Guidance Base Full Standby*
*Reduction in Force: 2.5 Scientists, 2 Students, 3 Engineers, 2 Technicians
FY07 Research Operation Scenarios(0, 6, 12, 16, 20 and 25 weeks)
28.82525.42023.51622.21221.1618.90
NationalBudget (M$)
ResearchWeeks
Implications if 0 Week (Standby) Budget in FY 2007
• Reductions in force– 2.5 Scientists, 2 Students, 3 Engineers, 2
Technicians • Highly constrained physics progress• Devastating dislocation for graduate students• 1 year delay Advanced Tokamak program• Delays in all facets of the research program, including
numerous high priority ITER R&D areas• No experimental contributions for joint ITPA research• Defer completion of key facility upgrades, including 2nd
LH launcher, 4-strap ICRF antenna
Incremental Funds (~10%) Would Significantly Improve Progress
• Facility Operation: 6 additional run weeks– Fewer than 1/3 of priority runs can be accommodated in
12 weeks (FY06)• Significantly earlier implementation of key upgrades
– W-brush tile outer divertor• ITER material and tile configuration
– 4th MW Lower Hybrid Source Power• Increased reliability, increased utilization
– Real-time matching – final 3 ICRF transmitters– Spare LH Klystron
Additional Run Time on C-Mod in FY07 Will Enable Significant New Scientific Progress
25 Weeks20 Weeks16 Weeks12 Weeks6 WeeksRuntime
Fully non-inductive, quasi-steady-state
Generation and control of ITBs via manipulation of B shear
50% non-inductive scenarios
Optimize hybrid scenarios with equilibrated electrons/ions
Active density control
Advanced Tokamak
High power handling of tungsten divertor
Characterize and exploit small ELM regimes
Exploit sustained high reactivity scenarios
H-mode pedestal scaling
Confinement at high Ip
Burning Plasma Support
Test feedback stabilization of NTMs
Fast-particle-driven collective modes in low/reversed shear
NTM Threshold at increased β
Macro-Stability
Real-time ICRF matching
LHCD with compound spectrum (2 launchers)
ICRF/LHCD synergies
Lower Hybrid j-profile control
Wave-Plasma
High-Z first wall studies
ITER prototype tungsten divertormodule studies
SOL turbulence and transport
Plasma Boundary
Nature of momentum coupling at edge
Role of equilibrium and fluctuating flows in L/H threshold
Compare near marginal stability fluctuations with non-linear GK models
Electron thermal transport
Momentum transport in torque-free discharges
Transport Science
Collaborations are Significant in all Aspects of the ProgramRecent Ideas Forum: 54/112 Ideas had first authors from 11 institutionsIn first 7 FY05 research days, 4 Session Leaders from U. Wisc, PPPL, JET, GA
Domestic Institutions
Princeton Plasma Physics LabU. Texas FRCU. AlaskaUC-DavisUC-Los AngelesUC-San DiegoCompXDartmouth U.GALLNLLodestarLANLU. MarylandMIT-PSFC TheoryORNLSNLAU. Texas IFSU. Wisconsin
International Institutions
Australian National UniversityBudker Institute, NovosibirskC.E.A. CadaracheC.R.P.P. LausanneCulham LabENEA/FrascatiIGI PaduaIPP GarchingIPP GreifswaldJET/EFDAJT60-U, JFT2-M/JAERIKFA JülichKFKI-RMKI BudapestLHD/NIFSPolitecnico di TorinoRisø National Laboratory. U. Toronto
C-Mod has Prominent Role in Education
• Typically have ~30 graduate students doing their Ph.D. research on C-Mod– Nuclear Engineering, Physics and EECS (MIT)– Collaborators also have students working at the
facility– Current total is 29
• MIT undergraduates participate through UROP program (~5 at any time)
• Host National Undergraduate Fusion Fellows
C-Mod Addressing Critical ITER R&D
• Transport/Confinement with equilibrated electrons and ions
• Pedestal physics– small/no ELM regimes; scaling
• All metal plasma facing components– T retention, disruptions– Comparisons of molybdenum and tungsten
• Disruption Mitigation in high absolute pressure plasma• Rotation in the absence of direct momentum input
– H-Mode dynamics; RWM stabilization• Error fields and locked modes
– size and field scaling• NTM physics
– direct stabilization; elimination of sawtooth seed• ICRF heating/CD/flow: High field, weak single pass• ICRF technology: load tolerance, antenna modeling• Alfven Eigenmode physics• AT physics toward steady state
IPPA 3.2, 3.3
W brush tiles assembled onto outer divertor leading
edge.
C-Mod is addressing High Priority ITER/ITPA Research Tasks
• Steady state operation– Hybrid scenarios
• Priority for AT thrust– Develop real time j profile control using heating and
CD actuators; assess predictability, in particular for off-axis CD
• Main thrust of LHCD program; also MCCD, FWCD
• State of the art modeling tools being developed and applied
• Transport Physics– Address reactor relevant conditions, e.g. electron
heating, Te~Ti, impurities, density, edge-core interaction, low momentum input …
• >90% of C-Mod operation is in these regimes– Encourage tests of simulation predictions via
comparisons to measurements of turbulence characteristics, code-code comparisons and comparisons to transport scalings
• Upgraded turbulence diagnostics• Increasingly strong interactions with theory and
modeling– Obtaining physics documentation for transport
modeling of ITER hybrid and steady-state demonstration discharges
TORIC Full-Wave Simulation in excellent agreement with
experimental (PCI) measurements of both density fluctuations and
wavenumber
C-Mod is addressing High Priority ITER/ITPA Research Tasks (2)
• MHD– Develop disruption mitigation techniques, particularly
by noble gas injection• Will investigate at absolute plasma pressures
comparable to those on ITER– Study fast particle collective modes in low and
reversed shear configurations: identify key parameters; perform theory data comparisons
• Active and passive MHD, PCI, ICRF• Strong theory and modeling effort
– Perform MHD stability analysis of H-mode edge transport barrier under type I and tolerable ELM conditions
• Focusing on small ELM and EDA regimes• Access to type I ELMs in 2004; will pursue
further– Investigate/determine island onset threshold of
NTMs … seed island control• Study at increased β• Sawtooth stabilization (ICRF, LH)
– Construct new disruption DB including conventional and advanced scenarios and heat loads on wall/targets
• Contribute data from all scenarios at high absolute power/energy densities
Alfvén cascades during current rampup
Model Experiment
C-Mod is addressing High Priority ITER/ITPA Research Tasks (3)
• Pedestal and Edge– Construct physics-based and empirical scaling
of pedestal parameters• Priority of transport task group; coordinated
experiments through ITPA– Improve predictive capability for ELM size and
frequency and assess accessibility to regimes with small or no ELMs
• Emphasis on small ELMs at higher β, and EDA
– Effects of collisionality studied through joint experiments
– Improve predictive capability of pedestal structure through profile modeling
• Supplying data to new pedestal profile database
• Confinement Database and Modeling– Evaluate global and local models for plasma
confinement by testing against databases• C-Mod operates with unique dimensional
parameters, providing important constraints
Stability of edge pedestal correlates with edge regulation
C-Mod is addressing High Priority ITER/ITPA Research Tasks (4)
• Divertor and SOL– Understand the effect of disruptions on divertor and first
wall structures• IR and ultra-fast imaging• Disruption mitigation
– Improve understanding of tritium retention and the processes that determine it
• Understanding D levels on tiles (including sides) for B and Mo
• Understanding removal of H at low tile temperature– Lyman-α absorption in divertor
• Unique high density regime on C-Mod– Improve understanding of SOL plasma interaction with
main chamber– Develop improved prescription of SOL perpendicular
transport and boundary conditions for input to modeling• SOL transport studies are a central emphasis
addressing both issues• Diagnostics
– Develop new methods to measure steady state magnetic fields accurately in nuclear environment
• Polarimetry is inherently steady-state; no in-principle special difficulty with nuclear environment
– Assess techniques for measurement of dust• Dust detection system being developed for in-situ
measurements during plasma pulses
Turbulence phase velocity changes across the separatrix
C-Mod Actively Participating in Joint Experiments Coordinated through ITPA
• Confinement scaling in ELMy H-modes• Scaling ν* along ITER-relevant path at high & low β• Steady-state plasma development• Physics investigation of transport mechanisms with Te~Ti at
high n• Similarity experiments with off-axis ICRF-generated n
peaking• Empirical scaling of spontaneous plasma rotation• Pedestal width analysis by dimensionless edge identity
experiments• Comparison between C-Mod EDA and JFT2-M HRS regimes• Small ELM regime comparisons• Scaling of radial SOL transport• Role of Lyman absorption in the divertor• Multi-machine modeling & database for edge n and T
profiles• Deuterium codeposition with boron in gaps of PFC’s• Inter-machine comparisons of SOL blobs• Disruption mitigation by massive gas jet• NTM studies, including error field effects• Sawtooth control mechanisms for NTM suppression• Low beta error field experiments• Fast ion redistribution by energetic particle driven Alfven
modes & thresholds for Alfven cascades• Measurement of damping rates for intermediate n Alfven
modes
H, D and Boron analysis on Mo tiles
0 2 4 6 8BT (T)
10-5
10-4
10-3
10-2
B~ /BT
q95=3.2
ITE
R fi
eld
Field scaling of locked mode threshold
AT Operation likely needed for Successful ITER Quasi-Steady-State
• C-Mod poised to enter key new phase of AT program: demonstrate RF tools for current profile control– Commissioning and learning to
use LHCD is top priority in FY05
• Good progress in understanding and optimizing core transport barriers with localized ICRF– Higher power, central n and T– As j(r) control becomes
available, explore influence of shear on transport and barriers
• Move toward integration of tools to produce high bootstrap fraction, non-inductive, long-pulse– Modeling, incorporating latest
wave-plasma and transport understanding is key
2 3 / 21.4e
CR
eff
Ta
Z
κτ =
Te = 6 keV (ITER 19 keV) Zeff = 2
C-Mod capable of very long normalized pulse-length
IPPA 3.1
Lower Hybrid Current Drive Facility UpgradeOperation into plasma began March 2005
• Initial experiments FY05• Current profile control
– 3 MW source, 1 launcher– FY06: 50% non-inductive– FY07-08: Fully non-inductive at
no-wall limit, t ≥ 5τC.R.
12 Klystrons (4.6 GHz, 3 MW) Operational, Connected through the Rear Waveguides to the Launcher
Launcher installed in-vessel
• After first week of operation:– 120 kW into plasma– Testing phase control, coupling
IPPA 3.1
C-Mod Fusion Science Priorities
Gyrokinetic simulations revealing role of ITG and TEM on evolution
and control of ITBs
• Transport IPPA 1.1– Self-generated flows and momentum
transport (including coupling to edge and SOL and identity expts with DIII-D)
– Edge flows, topology and H-mode threshold– Electron thermal transport and fluctuations– H-mode pedestal width scaling and physics– H-mode pedestal relaxation (including
EDA/QC and small ELM regimes)– ITB access and control mechanisms
(extending to weak and reversed shear regimes via LHCD)
• Plasma Boundary IPPA 1.4– Turbulence and EDGE/SOL transport– Edge flows and coupling to core rotation– Isotope retention and recycling– Tungsten brush prototypes (Burning
Plasma)
C-Mod Fusion Science Priorities (cont’d)
• Waves IPPA 1.3– Ion Cyclotron
• Minority 3He heating (50 MHz first, then 80 MHz@8 T)
• Mode conversion current, flow drive– Lower Hybrid
• Coupling physics• Phase studies (current drive,
heating, radial deposition)• Macroscopic Stability IPPA 1.2
– Disruption mitigation (massive gas puff)
– Locked modes (joint experiments)
– Alfven modes, cascades– NTM β threshold studies (joint
with DIII-D/JET)
Dramatic effects on sawteeth depend on phasing of ICRF
C-Mod Well Aligned with US Priorities
T1. How does magnetic field structure impact fusion plasma confinement?T2. What limits the maximum pressure that can be achieved in laboratory
plasmas?T3. How can external control and plasma self-organization be used to improve
fusion performance?T4. How does turbulence cause heat, particles, and momentum to escape from
plasmas?T5. How are electromagnetic fields and mass flows generated in plasmas?T6. How do magnetic fields in plasmas reconnect and dissipate their energy?T7. How can high energy density plasmas be assembled and ignited in the
laboratory?T8. How do hydrodynamic instabilities affect implosions to high energy density?T9. How can heavy ion beams be compressed to the high intensities required to
create high energy density matter and fusion conditions?T10. How can a 100-million-degree-C burning plasma be interfaced to its room
temperature surroundings?T11. How do electromagnetic waves interact with plasma?T12. How do high-energy particles interact with plasma?T13. How does the challenging fusion environment affect plasma chamber systems?T14. What are the operating limits for materials in the harsh fusion environment?T15. How can systems be engineered to heat, fuel, pump, and confine steady-
state or repetitively-pulsed burning plasma?
FESAC Priorities Panel Questions (C. Baker presentation at APS, preliminary)
C-Mod Contributes Strongly to 5 of 6 Identified Areas of “Opportunities for Enhanced Progress”
• Top 6 priorities for incremental resources:– Support ITER construction and operation, including
diagnostic R&D.– Predict the formation, structure, and transient
evolution of the H-mode edge pedestal with high confidence.
– Support the TTF initiative with emphasis on extended understanding of electron-scale transport.
– Develop an integrated understanding of plasma self-organization and external control, enabling high-pressure sustained plasmas.
– Understand electron transport and laser-plasma interactions for Fast-Ignition high-energy density plasmas.
– Extend understanding and capability to control and manipulate plasmas with external waves.
Research Goals (FY05-FY07)
FY 2005Measure plasma behavior with high-Z antenna guards and P>3.5 MW
FY 2006Current profile control with microwaves
FY 2007Confinement at high plasma current
FY 2006Disruption mitigation of high pressure plasma
FY 2005Commissioning of the microwave current drive system (LHRF)
FY 2006Sustaining plasma current without a transformer (50% non-inductive)
FY 2007Active density control
Targets and Milestones
• FY05 Level 1 JOULE Target– Measure plasma behavior with high-
Z antenna guards and input power greater than 3.5 MW.
• Addresses issues related to first wall choices, and the trade-offs between low-Z and high-Z materials.
• Can affect many important aspects of tokamak operation, including:
– impurity content and radiation losses from the plasma
– hydrogen isotope content in the plasma and retention in the walls
– disruption hardiness of device components.
• All significant when considering choices for next step devices to study burning plasma physics, especially ITER.
2-Strap ICRF Antenna with Mo Guards
Targets and Milestones (cont’d)
• Commissioning the Lower Hybrid Current Drive System (FY05) – First experiments begun
• Disruption mitigation of high absolute pressure plasma (FY05)– High-pressure massive gas-puff
injection• Current profile control with
microwaves (FY05-06)– Far off-axis current drive
• Non-inductive sustainment of plasma current (FY06)– Intermediate goal: 50% non-
inductiveDisruption mitigation gas tube
(outlet 2 cm from LCFS)
Targets and Milestones (cont’d)
• Active Density Control (FY06-07) – Install divertor cryopump
FY06– Low density H-modes
for AT regimes with efficient LH current-drive
• Confinement at high plasma current (FY05-07)– Ip ≥ 1.6 MA
C-Mod National Budgets (k$, Mar 2005 Guidance)
407307399307190Capital Equipment
28,21721,54726,31021,54722,269Alcator Project Total
12010012010097LANL Collaborations
480425480425425U. Tx. FRC Collaborations
2,2502,0502,2502,0502,070PPPL Collaborations
149149149149146MDSplus
4747474747International Collaborations
17,48612,50016,23412,50013,344Operations
7,2785,9696,6315,9695,950Research
FY07BProg Plan
FY07A12 wks
FY06BProg Plan
FY06AGuidance
FY05Approp
Summary National Budgets, Run-time and Staffing
FY04Actual
FY05Approp.
FY06Request
FY0612 wks
FY070 wks
FY0712 wks
FY0725 wks
Funding ($ Thousands)Research 6,122 5,972 5,972 5,698 6,181 7,640Facility Operations 12,900 12,595 12,595 10,789 13,039 17,819Research Capital Equipment 200 197 197 145 197 197Operations Capital Equipment 100 100 100 30 100 100PPPL Collaborations 2,052 2,002 2,002 1,702 2,002 2,250UTx Collaborations 415 415 415 374 415 480LANL Collaborations 100 100 100 90 100 120MDSplus 149 149 149 149 149 149International Activities 47 60 60 60 60 60Total (inc. International) 22,085 21,590 21,590 19,037 22,243 28,815Staff Levels (FTEs)Scientists & Engineers 53.83 54.58 54.58 48.93 54.53 68.93Technicians 26.37 25.97 25.97 21.87 25.77 31.37Admin/Support/Clerical/OH 13.61 13.21 13.21 11.23 12.57 14.08Professors 0.21 0.21 0.21 0.21 0.21 0.21Postdocs 2.00 2.00 2.00 1.00 2.00 2.00Graduate Students 26.55 25.55 25.55 22.55 25.55 28.55Industrial Subcontractors 1.50 1.30 1.30 0.00 1.10 1.00Total 124.07 122.82 122.82 105.79 121.73 146.14Facility Run ScheduleScheduled Research Run Weeks 19 17 12 12 0 12 25Users (Annual) Host 56 54 53 53 0 53 60 Non-host (US) 95 93 90 90 0 90 95 Non-host (foreign) 12 10 10 10 0 10 18Graduate students 29 29 29 29 0 27 31Total Users 192 186 182 182 0 180 204Operations Staff (Annual) Host 71 69 68 68 62 68 77 Non-host 4 4 4 4 3 4 5Total 75 73 72 72 65 72 82
C-Mod Major Contributor to Fusion Science and Preparations for Burning Plasma
• Unique dimensional regimes• ITER relevant heating and current
drive tools, metal PFCs• Increasingly strong collaborations• Well aligned with Opportunities and
Priorities• Strong, broad contributions to high
priority ITPA research• Exciting prospects in coming 3
years with new tools and diagnostics– LHCD; cryopump– Disruption mitigation– Turbulence measurements– CNPA, Hard X, long-pulse DNB– All digital plasma control system
• Tight coupling to theory and modeling
C-Mod ITER/9
Ip = 1.6MA, BT = 5.3T
Ip = 15MA, BT = 5.3T
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