development of burning plasma and advanced scenarios in ... · itpa joint experiment cordey –...

Development of Burning Plasmaand Advanced Scenarios

in the DIII–D Tokamak

NATIONAL FUSION FACILITYS A N D I E G O

DIII–D248-04/TCL//rs

byT.C. Luce

for the DIII–D Team

Presented at20th IAEA Fusion Energy Conference

Vilamoura, Portugal

November 1, 2004

QTYUIOP

THE DIII–D TEAMCONSISTS OF >300 PROFESSIONALS FROM >70 INSTITUTIONS

European Community

Cadarache (St. Paul-lez, Durance, France)Consorzia RFX (Padua, Italy)Culham (Culham, Oxfordshire, England)Frascati (Frascati, Lazio, Italy)FOM (Utrecht, The Netherlands)IPP (Garching, Greifswald, Germany)JET-EFDA (Oxfordshire, England)KFA (Julich, Germany)Kharkov IPT, (Ukraine)Lausanne (Lausanne, Switzerland)Chalmers U. (Goteberg, Sweden)Helsinki U. (Helsinki, Finland)U. Naples (Naples, Italy)U. Strathclyde (Glasgow, Scotland)U. Wales (Wales)

Russia

Ioffe (St. Petersburg, Russia)Keldysh (Udmurtia, Moscow, Russia)Kurchatov (Moscow, Russia)Moscow State (Moscow, Russia)Triniti (Troitsk, Russia)Gycom (Nizhny Novgorod, Russia)

Other International

Australia National U. (Canberra, AU)ASIPP (Hefei, China)KAIST (Daegon, S. Korea)KBSI (Daegon, S. Korea)National U. (Taiwan)Nat. Nucl. Ctr. (Kurchatov City, Kazakhstan)SWIP (Chengdu, China)U. Alberta (Alberta, Canada)U. of Kiel (Kiel, Germany)U. Toronto (Toronto, Canada)

US Industries

CompX (Del Mar, CA)CPI (Palo Alto, CA)Creare (Hanover, NH)Digital Finetec (Ventura, CA)FAR Tech (San Diego, CA)HiTech Metallurgical (San Diego, CA)IR&T (Santa Monica, CA)Orincon (San Diego, CA)SAIC (La Jolla, CA)Surmet (Burlington, MA)Thermacore (Lancaster, PA)TSI Research (Solana Beach, CA)

Japan

JAERI (Naka, Ibaraki-ken, Japan) JT-60U JFT-2MTsukuba University (Tsukuba, Japan)NIFS (Toki, Gifu-ken, Japan) LHD

US Labs

ANL (Argonne, IL)INEL (Idaho Falls, ID)LANL (Los Alamos, NM)LLNL (Livermore, CA)ORNL (Oak Ridge, TN)PNL (Richland, WA)PPPL (Princeton, NJ)SNL (Sandia, NM)

US Universities

Alaska (Fairbanks, AK)Auburn (Auburn, Alabama)Cal Tech (Pasadena, CA)Colorado School of Mines (Golden, CO)Columbia (New York, NY)Georgia Tech (Atlanta, GA)Hampton (Hampton, VA)Lehigh (Bethlehem, PA)Maryland (College Park, MD)MIT (Boston, MA)Palomar (San Marcos, CA)New York U. (New York, NY)Texas (Austin, TX)UCB (Berkeley, CA)UCI (Irvine, CA)UCLA (Los Angeles, CA)UCSD (San Diego, CA)U. New Mexico (Albuquerque, NM)Washington (Seattle, WA)Wisconsin (Madison, WI)

NakaDaejon

HefeiChengdu

Taiwan

Kurchatov City

Moscow

Durance

Culham

Goteberg

Helsinki

Utrecht

Wales

JulichMontreal

Fairbanks

Alberta

SeattleRichland

Idaho FallsDenver

Toronto

Frascati

Garching

Lausanne

St. Petersburg

Troitsk

Nizhny Novgorod

TsukubaToki

BerkeleyPalo Alto

Livermore

AustinAtlanta

Oak Ridge

HamptonLancaster

PrincetonNew York

Boston & BurlingtonHanover

BethlehemCollege Park

SandiaLos Alamos

MadisonArgonne

LA Area Santa Monica Pasadena Irvine

San Diego Area Del Mar Solana Beach San Marcos

Canberra

248-04/TLC/rsNATIONAL FUSION FACILITY

S A N D I E G O

DIII–D

DIII–D PROGRAM GOAL: TO ESTABLISH THE SCIENTIFIC BASIS FOR THE OPTIMIZATION OF THE TOKAMAK

248-04/TCL/rsNATIONAL FUSION FACILITY

S A N D I E G O

DIII–D

Strengthening the scientific basis for next-generation burning plasma experiments (ITER)

Establishing the scientific basis for steady-state tokamak operation

Investigating fundamental properties of tokamak plasma

Highlights presented here are organized around three themes:

DIII–D EXPERIMENTS INCREASE CONFIDENCEIN REACHING THE ITER PERFORMANCE TARGETS


S A N D I E G O

DIII–D

Stationary discharges with: — Performance >40% higher than the ITER baseline scenario — Performance equal to the ITER performance target obtained at 30% lower equivalent current

G = βNH89/q95 2

Normalized Fusion Performance

Duration Relative to Current Relaxation Time

G

tdur/τR0 2 4 6 108

ITER BaselineScenario Target

Baseline ScenarioHybrid ScenarioOther

0.0

0.2

0.4

0.6

0.8

1.0

STATIONARY HIGH PERFORMANCE ACHIEVED UNDER CONDITIONS SIMILAR TO THE ITER BASELINE SCENARIO


S A N D I E G O

DIII–D

Key advance is operation at higher pressure (βN = 2.8), due to initiation at a relatively benign resistive instability (m=3/n=2 tearing mode) before the onset of sawteeth

ITPA Joint Experiment Wade – Wed. PM Talk

βN

4 liH89P

τR τE

I × 10 (MA)

120675

Sawteeth Type I ELMsq95=3.2

<β>=4.0%

tdur=9.5 stdur/τR=9.2tdur/τE=55

0 2 4 6 8 10 12Time (s)

G

0

3

6

9

12

0

1

2

3

4

0.00.20.40.60.81.0

PNB (MW) <PNB> (MW)<PNB> (MW)

STATIONARY HIGH PERFORMANCE ACHIEVED UNDER CONDITIONS SIMILAR TO THE ITER BASELINE SCENARIO


S A N D I E G O

DIII–D

Projection to ITERβN = 2.8 q95 = 3.2 n/nG = 0.85

B = 5.3 T I = 13.9 MA

ITER89P 2.4 780 60 12.9IPB98y2 1.47 740 18.5 39DS03 1.25 700 0 ∞

*DIII–D Value

βN4 li

ITPA Joint Experiment

PNB (MW)

I×10 (MA)

ITER BaselineTarget

G

120675

Wade – Wed. PM Talk

(1.63)*

0 2 4 6 8 10 12Time (s)

1.00.8

0.6

0.4

0.2

0.0

0

3

6

9

12

0

1

2

3

4

<PNB> (MW)<PNB> (MW)

H89PH89P

ITER BaselineTarget

ITER BaselineTarget

Flattop time = 2300 s > 30 min

HPfus (MW)

Paux (MW) Qfus

CANDIDATE HYBRID SCENARIO DISCHARGES REACH ITERPERFORMANCE TARGET AT REDUCED EQUIVALENT CURRENT


S A N D I E G O

DIII–D

Hybrid scenario goal is maximum fusion energy (or neutron fluence) per inductive pulse

DIII–D approach is reduced current and higher normalized pressure, up to no-wall pressure limit (~4 li)

Key advance is again the initiation of a resistive mode (m=3/n=2), which prevents the onset of sawteeth and allows high normalized pressure (βN ≤ 3.2)

I×10 (MA)

βN

4 li

H89P

119733


0 2 4 6 8Time (s)

G

⟨β⟩ = 3.1%

τR τE

0

3

6

9

12

0

1

2

3

4

0.0

0.2

0.4

0.6

0.8

1.0

PNB (MW)


CANDIDATE HYBRID SCENARIO DISCHARGES REACH ITERPERFORMANCE TARGET AT REDUCED EQUIVALENT CURRENT


S A N D I E G O

DIII–D

I×10 (MA)

βN

4 li

ITER BaselineTarget

ITER Baseline Target

ITER BaselineTarget

H89P

119733

Projection to ITER

ITER89P

IPB98y2

DS03

2.75

1.59

1.78

(1.81)*

440

440

370

49

49

0

9.0

9.0

∞

HPfus (MW)

Paux (MW) Qfus

βN = 2.7 q95=4.4 n/nG = 0.85B = 5.3 T I = 10.8 MA


*DIII–D Actual Value

0 2 4 6 8Time (s)

G

0

3

6

9

12

0

1

2

3

4

1.0

0.8

0.6

0.4

0.2

0.0

PNB (MW)


Flattop Time = 3900s >1 hour

DIMENSIONLESS SCALING EXPERIMENTS SHOWENERGY CONFINEMENT IS INDEPENDENT OF BETA


S A N D I E G O

DIII–D

β scalings for direct experiments and database analysis are very different

DIII–DJET

0 1 2 3thβN

IPB98 y2 Prediction

α

0.5

τE ∝βα

0.0

–0.5

–1.0

ITPA Joint Experiment Cordey – Thurs. AM Poster

τE=0.0562 I0.93 B0.15 n0.41 P–0.69 R1.97 A–0.58 κ0.78 M0.19

BτE

∝ ρ*–2.70 β–0.90 ν

*–0.01 q–3.0

IPB98y2

τE=0.028 I0.83 B0.07 n0.49 P–0.55 R2.11 A–0.3 κ0.75 M0.14

BτE

∝ ρ*–3 β0 ν

*–0.14 q–1.7

DS03

Absence of β dependence is consistent with drift-type turbulence

STATIONARY HIGH PERFORMANCE DISCHARGES HAVEBEEN OBTAINED OVER A WIDE RANGE OF PARAMETERS

248-04/TCL/rsNATIONAL FUSION FACILITYS A N D I E G O

DIII–D

Pressure limit higher without sawteeth

Fusion performance maximizes at low q95

Confinement drops slightly with increasing density

βN

G=βNH89/q952

q95

Sawteeth No Sawteeth

ITER BaselineTarget

ITER Baseline Target


2.5 3.0 3.5 4.0 4.5 5.0q_951

2

3

4

2.5 3.0 3.5 4.0 4.5 5.00.0

0.2

0.4

0.6

0.8

H98y2

ITER ν* Ti/Te = 1

0.0 0.2 0.4 0.6 0.8 1.0ne /nG

0.5

1.0

1.5

2.0

2.5

3.0q95=4.4

q95=3.2H89

ITERBaselineTarget

ROBUST STABILIZATION OF m=2/n=1 TEARING MODEOBTAINED WITH ELECTRON CYCLOTRON CURRENT DRIVE


S A N D I E G O

DIII–D

This instability sets the operational β limit in the ITER baseline scenario. Locking of this mode often leads to disruptions ⇒ stabilization would avoid more extreme mitigation measures

Stabilization is obtained at high pressure (βN = 2.8, βP = 1.1)

Stabilization is optimized automatically by active feedback system to place the ECCD at the location of the instability

Petty – Thurs. PM Talk

βN

βp

116015

B (n=1) (G)~

PEC (MW)

0 2 4 6 8Time (s)

I × 10 (MA)

PNB (MW)

0

10

20

30

0

2

4

6

0

1

2

3

4

0

5

10

15

<PNB> (MW)

STOCHASTIC EDGE ELIMINATES LARGE TYPE-I ELMS


S A N D I E G O

DIII–D

Non-axisymmetric fields (n=3) have been used to eliminate ELMs — Edge instability changes character — Power flow is still to the divertor — Technique applied in ITER shape

Impulsive heat flux reduced by at least a factor of 3

Confinement and edge pedestal height unchanged

Evans – Tues. PM Talk

0 1 2 3 4 5 6

0 1 2 3 4 5 6

W (MJ)

3.0 3.5 4.0 4.5Time (s)

Div. Dα (a.u.)

n=3 FieldAmplitude

n (1019/m3)

0

2

4

6

8119700 (coils off) 119690 (coils on)

0.00.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

CARBON MIGRATION USING 13C AS A TRACER INDICATESTRITIUM CO-DEPOSITION MAY BE LOCALIZED

AT THE INNER DIVERTOR


S A N D I E G O

DIII–D

Measured deposition highly localized at inner divertor; toroidally symmetric

Modeling of deposition, carbon plume, and core carbon inventory requires flow velocity M~0.4 at the separatrix in the direction of the inner divertor

116243 3000.00EFIT03

13CInjection

Deposition

67

89 109A

9A

11 1212A

12A

Technique Pioneeredby JET

1516 17

0

1

2

3

C13

(10

17 A

tom

s/cm

2 )

Inner Strike Point Outer Strike Point

6 7 8 9 121110 15 16 17


S A N D I E G O

DIII–D

Full non-inductive discharges in present tokamaks that project to high fusion gain are a necessary first step

Control of discharge parameters and instabilities will be an essential component of a steady-state tokamak

Baseline Scenario(qmin ~1, q95 ~3)

1.0 2G = βN H89/q95

0.8

0.6

G

0.4

0.2

0.00.0 0.2 0.4

Bootstrap Current Fraction

fBS

0.6 0.8 1.0

Hybrid Scenario(qmin ~1, q95 ~4)

Steady-StateScenario(qmin = 1.5–2.5,q95 = 4–6)

ITER Steady-State Target

STEADY-STATE TOKAMAK OPERATION REQUIRES A COMPROMISEBETWEEN FUSION PERFORMANCE AND BOOTSTRAP CURRENT

Other

FULL NON-INDUCTIVE DEMONSTRATIONDISCHARGE HAS BEEN OBTAINED


S A N D I E G O

DIII–D

Pressure at or above the no-wall pressure limit (βN≥4 li) for high fusion power

Elevated qmin (>1.5) for enhanced bootstrap current (fBS ~0.6)

Reduced current (q95 ~5) to minimize non-inductive current requirements

βN

4 liH89

Vsurf (V)

120096

ITPA Joint Experiment Murakami – Tues. AM Talk

G

2.0 2.5 3.0 3.5 4.0 4.5 5.0Time (s)

01

2

34

–0.1

0.0

0.1

0.20.00.10.20.30.40.5

0

5

10

15

PNB (MW)

I × 10 (MA)

PEC (MW)<PNB> (MW)

FULL NON-INDUCTIVE DEMONSTRATIONDISCHARGE HAS BEEN OBTAINED


S A N D I E G O

DIII–D

B = 5.3 T

I = 9.3 MA

n = 0.63×1020 m–3

PNB = 33 MW

PEC = 20 MW

PIC = 20 MW

Pfus = 340 MW

Type I ELMs

βN = 2.8

q95 = 5.4

HDS03 = 1.28

INB = 2.3 MA

IEC = 0.5 MA

IIC = 0 MA

IBS = 6.7 MA

Qfus = 4.7


βN

4 liH89

Vsurf (V)

120096

G ITER Steady-State Target

2.0 2.5 3.0 3.5 4.0 4.5 5.0Time (s)

01

2

34

–0.1

0.0

0.1

0.20.00.10.20.30.40.5

0

5

10

15

PNB (MW)

I × 10 (MA)

PEC (MW)<PNB> (MW)

MEASUREMENTS AND MODELING INDICATE FULL NON-INDUCTIVECURRENT SUSTAINMENT WITH GOOD ALIGNMENT


DIII–D

Surface voltage from equilibrium reconstructions shows no net inductive flux (but note ℜ = 0.15 µΩ ⇒ 15 mV = 100 kA)

Internal electric field determined from equilibrium reconstructions shows little spatial structure ⇒ non-inductive sources well aligned to total current

Toroidal electric field inferred directly from MSE data confirms equilibrium analysis

Modeling gives nearly full non-inductive current: — Bootstrap 59% — Neutral Beam 31% — Electron cyclotron 8% — Inductive 2%

JTOT

JIND

0.0 0.2 0.4 0.6 0.8 1.0ρ–50

0

50

J (A

/cm

2 )

100

150Measurements Modeling


0.0 0.2 0.4 0.6 0.8 1.0

JTOT

JEC

JBSJNB

JIND

Radius, ρ

J (A

/cm

2 )

–50

0

50

100

150

TRANSFORMERLESS OPERATION SHOWS CONTROL OFHIGH BOOTSTRAP FRACTION PLASMAS WILL BE CHALLENGING


DIII–D

The desired steady-state operating point may not be a stationary solution to the coupled fluid equations. If not, active control is required.

Inductive control of the plasma current may be desirable ⇒ non-inductive overdrive will be required.

At high safety factor (q95~10) and high qmin (~3), the bootstrap current fraction is >80%.

PNB (MW)

119787

Politzer – Wed. PM Poster

I (MA)

0 1 2 3 4 5 6Time (s)

qmin

βN

4 liH89

<PNB> (MW)

0

5

10

15

0.50

0.60

0.70

0

1

2

3

4

1

2

3

4

ACTIVE RESISTIVE WALL MODE STABILIZATION ALLOWSEXTENDED OPERATION ABOVE THE NO-WALL PRESSURE LIMIT


DIII–D

Rotation is effective in stabilizing the RWM up to the ideal-wall limit in many cases

Rotation is ineffective in the case shown, perhaps due to a reduction in the number of rational surfaces in the plasma interior (lower q95)

Active feedback using the 12 internal coils in n=1 symmetry allows operation above the no-wall limit for ~200 growth times

1.0 2.01.5 2.5Time (s)

30

0

200

Estimated no-wall limit n=1 current

βN

0

4

Vφ (km/s)

∆Br (n=1) (G)

0

With Feedback 119666 Without Feedback 119663

Okabayashi – Wed. AM Talk

PROGRESS IN UNDERSTANDING TOKAMAK PHENOMENAIS BEING MADE IN MANY AREAS


S A N D I E G O

DIII–D

Magnetic geometry changes the character of the sawtooth instability

Development of diagnostics and theory to understand the H–mode pedestal

Electron heat transport exhibits no threshold behavior

Plasma fueling is dominated by neutrals originating in the divertor

Plasma rotation is strongly changed by ECH (no external torque applied)

Gas jets mitigate disruptions safely despite a short penetration length

SAWTOOTH INSTABILITY CHANGES CHARACTERWITH CROSS-SECTION SHAPE


S A N D I E G O

DIII–DLazarus – Fri. AM Poster

Indented plasmas:— Electron and ion temperatures remain close

— Significant evolution of the central current density

Oval plasmas:— Ion temperature significantly above electron temperature despite roughly equal heating

— No significant evolution of the central current density

Te (keV)

Ti (keV)

Pitch Angle (deg)

PLASMAS THAT VIOLATE THE MERCIER CRITERIONDO NOT SUPPORT AN ELECTRON PRESSURE GRADIENT


S A N D I E G O

DIII–D

Mercier limit occurs at q<1

Local electron heating results in strongly increased gradient

Mercier limit occurs at q>1

Local electron heating results in almost no change in gradient

Lazarus – Fri. AM Poster

1.2 1.4 1.6 1.8 2.0 2.2Rvac (m)

0

1

2

3

4

5

Te (k

eV)

3000 3050 3100 3150Time (ms)

0

1

2

3

4

5

1.2 1.4 1.6 1.8 2.0 2.2Rvac (m)

0

1

2

3

4

5

Te (k

eV)

3700 3740 3780Time (ms)

0

1

2

3

4

5

118163

CentralTe

ECHPower

118150

118163

118150 Oval Plasmas:

Indented Plasmas:

PREDICTIVE UNDERSTANDING OF THE EDGE PEDESTAL REQUIRESCONTINUING IMROVEMENTS IN MEASUREMENT AND THEORY


S A N D I E G O

DIII–D

Need continuous electron pressure measurement

Pedestal Pressure Pedestal Current Stability Theory

Need improved time resolution

Need nonlinear (time-dependent) theory

–10.0 –5.0 0.0R–Rsep (cm)

5.0

Fenstermacher – Wed. AM Poster West – Thurs. AM Poster

Er (kV/m)

R–Rsep (cm)

2.252.202.15R (m)

ELITE n=18DIII–D 119449

PeelingUnstable

Strong Shaping

BallooningUnstableWeak Shaping

Stable

p′ped

J ped

0

–100

–50

50–10

0

10

20

30 JTOR (A/cm2)JTOR (A/cm2)

JBS (calc)–150.0

0.3

0.6

CVI Density0.9(1018 m3)

1.2

1.5

–10 –5 0 5

CONCLUSIONS


S A N D I E G O

DIII–D

Performance projections for ITER using the present design basis are conservative. DIII–D results provide confidence in reaching the ITER performance targets and optimism that they can be exceeded. Technical challenges are being addressed actively.

A steady-state tokamak scenario has been demonstrated in DIII–D that projects to modest fusion gain in ITER. The ability to control such plasmas near the performance boundaries is the next task.

The DIII–D facility is providing unprecedented views of tokamak phenomena, enabling the development and validation of theories and models of plasma behavior.

DIII–D AND GENERAL ATOMICS PRESENTATIONS


S A N D I E G O

DIII–D

Tuesday Wednesday Thursday Friday Saturday

AMTalks

Murakami –Steady-stateScenario

Evans – ELMs(Suppression, etc.)

Wade – HybridScenarios

Ferron – β Limitsin Steady-State ScenariosPolitzer – HighBootstrap Discharges

Solomon – PoloidalRotation

DeBoo – CriticalGradientsRhodes –TurbulenceMeasurements

Petty – TearingModes

Okabayashi –RWM Control

Fenstermacher –Pedestal Physics

Waltz –GyrokineticSimulations

Hollmann –Disruptions

West – QH–ModeKinsey – TransportModelingParks– Pellets

Petrie – DivertorGeometry and PumpingGroth – Plasma FuelingRudakov – SOL TransportLazarus – SawteethdeGrassie – Rotation

Nazikian – EnergeticParticlesFredrickson – MHDInstabilities

AMPosters

PMPosters

Burning Plasma Steady-State Tokamak Physics Other

PMTalks

development of burning plasma and advanced scenarios in ... · itpa joint experiment cordey –...

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