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