NATIONAL FUSION FACILITYS A N D I E G O
DIII–D248-04/MRW/jy
byM.R. Wade
for the DIII–D Team
November 3, 2004
Presented at 20th IAEA Fusion Energy Conference
Vilamoura, Portugal
Development, Physics Basis, andProjections of Hybrid Scenario
Operation in ITER on DIII–D
M.R. Wade,1 T.C. Luce,2 R.J. Jayakumar,3 P.A. Politzer,2 A.W. Hyatt,2 J.R. Ferron,2 C.M. Greenfield,2 E.H. Joffrin,4 M. Murakami,1 C.C. Petty,2
R. Prater,2 J.C. DeBoo,2 J. La Haye,2 P. Gohil,2 T.L. Rhodes,5 and A.C.C. Sips6
1Oak Ridge National Laboratory2General Atomics
3Lawrence Livermore National Laboratory4CEA Cadarache Euratom Association5University of California-Los Angeles
6Institut fur Plasmaphysik
0 2
ITERBaseline
(Qfus = 10)
4 6
Neutron Fluence Per Pulse (10–5 MW - year/m2)
Qfus = ∞
Qfus = 5
Materials Testing
8 10 120.0
0.2
0.4
0.6
0.8
1.0
1.2
P alph
a / P lo
ss
'HYBRID' REGIME: A NEW STANDARD IN STATIONARY TOKAMAK PERFORMANCE THAT OFFERS ENHANCED
RESEARCH OPPORTUNITIES IN ITER
263-04/MW/jy
● 'Hybrid' Regime was originally conceived to take advantage of improved performance and current drive capabilities to achieve long-pulse operation in ITER (at Qfus < 10)
● Over the past few years, DIII–D has demonstrated stationary operation with β ≥ 80% βno-wall and H89 > 2 over a wide range in q95 (2.8 < q95 < 5) and density (0.3 < neo/nGW < 0.75)
● Projections based on this data are uniformly positive and offer a wide range of operating options in ITER
— Qfus = ∞ (q95 = 3)
— Qfus = 10 for 3900 s (q95 = 4.4)
S A N D I E G O
DIII–DNATIONAL FUSION FACILITY
Burn
ing
Plas
ma
Phys
ics
Using FullTransformer Capability
Projections based on DIII–D data
RECENT EXPERIMENTS HAVE DEMONSTRATED TRULYSTATIONARY (> 9 τR), HIGH PERFORMANCE OPERATION
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
0.0
0.5
1.0
1.5 IP (MA)PNBI (MW/10)
βN
βT
H89
τR10 τE
H98y2
01234
01
2
0
5
10
15n = 1 B rmsn = 2 B rms
~~
Time (s)
0.0
2.5
5.0
(G)
⟨ne⟩ (1019 m–3)Zeff (ρ = 0.5)
Dα
0 2 4 6 8 10 12
Zeff =2.0
H98y2 =1.3
H89P =2.3
βT ≈4%
βN ≈2.7
NORMALIZED FUSION PERFORMANCE AND DURATION COMFORTABLY EXCEED THAT OF ITER BASELINE SCENARIO
263-04/MW/jy
G = βN
H89/q95 as measure of Pα/PLOSS
[Mikkelsen, Phys. Fluids B 1 333 (1989)]S A N D I E G O
DIII–DNATIONAL FUSION FACILITY
2
0.0
0.2
0.4
0.6
0.8
1.0G
0 2 4
q95 < 4q95 > 4
6 108
● Duration:● Fusion Performance:NτR = tdur/τR as measure of stationarity
NτR
ITER BaselineScenario Target
PERFORMANCE AT OR ABOVE ITER BASELINE DESIGN HAS BEEN ACHIEVED OVER A WIDE RANGE IN q95
263-04/MW/jy
● No Sawteeth
● βN ≈ βN
S A N D I E G O
DIII–DNATIONAL FUSION FACILITY
no-wall no-wall
● G ≈ GITER
● q95 = 3.2
● Small Sawteeth
● βN > 0.8 βN
● G ≈ 1.5 GITER
~
)
)
10 IP (MA) 10 IP (MA)
<PNB> (MW)
βNβN4 li
4 li
H89P H89P
G G
Time (s)
)
05
1015
113993 115863
0
2
4
0
2
4
0
2
4
0.0
0.5
1.0
ITER Baseline Scenario
ITER Baseline Scenario
ITER Baseline Scenario
ITER Baseline Scenario
ITER Baseline Scenario
ITER Baseline Scenario
05
1015
0
2
4
0.0
0.5
1.0
<PNB> (MW)
0 1 2 3 4 5 6Time (s)
0 1 2 3 4 5 6
● q95 = 4.4
FUSION PERFORMANCE MAXIMIZES AT LOW q95;G ª GITER AT q95 = 4.5
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
1
2
3
ITER BaselineSawteeth No Sawteeth
4
3.0 3.5 4.0 4.5 5.0 ITPA Joint Experiment0.5
1.0
1.5
2.0
2.5
3.0
bN
2
q95
ITER Baseline
G = bN H89/q95
ITER BaselineH98y2
H89
l All sustained for at least tR
2.5 3.0 3.5 4.0 4.5 5.0q_95
2.5 3.0 3.5 4.0 4.5 5.0q95
0.0
0.2
0.4
0.6
0.8
2.5
FUSION PERFORMANCE MAXIMIZES AT LOW q95;G ª GITER AT q95 = 4.5
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
1
2
3
ITER BaselineSawteeth No Sawteeth
4
ITPA Joint Experiment0.5
1.0
1.5
2.0
2.5
3.0
bN
2
q95
ITER Baseline
G = bN H89/q95
ITER BaselineH98y2
H89
2.5 3.0 3.5 4.0 4.5 5.0q_95
2.5 3.0 3.5 4.0 4.5 5.0q95
0.0
0.2
0.4
0.6
0.8
3.0 3.5 4.0 4.5 5.02.5
FUSION PERFORMANCE WEAKLY DEPENDENT ON PLASMA DENSITY
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● All discharges are at stationary (> τR) β limit
ITERBaseline
ITER Baseline
H89
ITER Baseline
ITPA Joint Experiment
βN
{
H98y2 {
1
2
3
4
0.0 0.2 0.4 0.6 0.8 1.0ne /nGW
0.5
1.0
1.5
2.0
2.5
3.0
0.0 0.2 0.4 0.6 0.8 1.0ne/nGW
0.0
0.2
0.4
0.6
0.8
q95 = 3.2 q95 = 4.5
2G = βN H89/q95
FUSION PERFORMANCE WEAKLY DEPENDENT ON PLASMA DENSITY
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● All discharges are at stationary (> τR) β limit
ITERBaseline
ITER Baseline
H89
ITER Baseline
ITPA Joint Experiment
βN
{
H98y2 {
1
2
3
4
0.0 0.2 0.4 0.6 0.8 1.0ne /nGW
0.5
1.0
1.5
2.0
2.5
3.0
1.0 1.5 2.0 2.5Central Ti/Te
0.0
0.2
0.4
0.6
0.8
q95 = 3.2 q95 = 4.5
2G = βN H89/q95
SAWTEETH BEHAVIOR DISTINGUISHES HYBRID REGIME FROM CONVENTIONAL REGIME
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● With early heating, sawteeth do not appear
q = 4.5n = 1 B rms (G/2)~ ~
βN
0
1
2
3 Hybrid
1.00.0 2.0 3.0Time (s)
4.0 5.0
Early Heating
n = 2 B rms (G/2)
SAWTEETH BEHAVIOR DISTINGUISHES HYBRID REGIME FROM CONVENTIONAL REGIME
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● With early heating, sawteeth do not appear
● Without early heating, m =2, n =1 NTM triggered by sawteeth at 20% lower βN
q = 4.5n = 1 B rms (G/2)~ ~
βN
0
1
2
3 Hybrid
0
1
2
3 Conventional
1.00.0 2.0 3.0Time (s)
4.0
2/1 NTMTriggered
5.0
No EarlyHeating
Early Heating
Sawteeth
n = 2 B rms (G/2)
SAWTEETH BEHAVIOR DISTINGUISHES HYBRID REGIME FROM CONVENTIONAL REGIME
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● With early heating, sawteeth do not appear
● Without early heating, m =2, n =1 NTM triggered by sawteeth at 20% lower βN
● At slightly lower βN, 2/1 mode not destabilized
● After 3/2 mode grows, sawteeth diminish
q = 4.5n = 1 B rms (G/2)~ ~
βN
0
1
2
3 Hybrid
0
1
2
3 Conventional
1.00.0 2.0 3.0Time (s)
4.0
2/1 NTMTriggered
5.00
1
2
3 Conventional → Hybrid
No EarlyHeating
No EarlyHeating
Early Heating
n = 2 B rms (G/2)
Sawteeth
Sawteeth
STUDIES HAVE SHOWN 3/2 NTM AMPLITUDE IS KEY TO AVOIDANCE OF SAWTEETH
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
012345
No 3/2mode
With 3/2mode
Sawteethn = 1 B rms (G)
~n = 2 B rms (G)
~
012345
3.0 4.0 5.0Time (s)
6.0 7.0
STUDIES HAVE SHOWN 3/2 NTM AMPLITUDE IS KEY TO AVOIDANCE OF SAWTEETH
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
012345
No 3/2mode 1.15
q (0
)
1.10
0.00 0.02 0.04
W3/2 (m)
0.06 0.08 0.10
1.05
1.00
0.95
Before ECCD
Co–ECCD
With 3/2mode
Co-ECCDsuppresses
3/2 mode
EC On
Sawteeth
Sawteeth
n = 1 B rms (G)~
n = 2 B rms (G)~
012345
012345
3.0 4.0 5.0Time (s)
6.0 7.0
STUDIES HAVE SHOWN 3/2 NTM AMPLITUDE IS KEY TO AVOIDANCE OF SAWTEETH
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
012345
No 3/2mode 1.15
q (0
)
1.10
0.00 0.02 0.04
W3/2 (m)
0.06 0.08 0.10
1.05
1.00
0.95
Counter–ECCD
Before ECCD
Co–ECCD
With 3/2mode
Co-ECCDsuppresses
3/2 mode
EC On
EC On
Ctr-ECCDenhances3/2 mode
Sawteeth
Sawteeth
n = 1 B rms (G)~
n = 2 B rms (G)~
012345
012345
3.0 4.0 5.0Time (s)
6.0 7.0012345
IMPROVED CONFINEMENT IS DUE TO GOOD TRANSPORTACROSS ENTIRE PROFILE
263-04/MW/jyS A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● Leads to broad pressure profile which is favorable for high β limit
0.0 0.2 0.4 0.6 0.8 1.0 1.2Normalized Radius
0.0 0.2 0.4 0.6 0.8 1.0 1.201
2
3
45
(keV
)
0.0 0.2 0.4 0.6 0.8 1.0 1.2Normalized Radius
02
4
6
810
(keV
)
0.0 0.2 0.4 0.6 0.8 1.0Normalized Radius
ne
Te
Ti
0
1
2
3
410
8
6
(101
9 m–3
)
4
20
(m2 /s
)
χeffχiχe
IMPROVED TRANSPORT APPEARS TO BE DUE TO THE INTERACTION OF SEVERAL EFFECTS
263-04/MW/jy
● Improved transport is likely due to a combination of reduced turbulence drive (γmax) associated with Ti/Te > 1 and a favorable current profile and increased stabilization via ExB shear
● GLF23 indicates sensitivity to ExB shear
● Experiments in 2006 should help resolve this issue
— Is this due to small γmax or large ExB shear?
— Balanced NBI— Increased electron heating capability
S A N D I E G O
DIII–DNATIONAL FUSION FACILITY
0
2
4
6
8
10
12
0.0 0.2 0.4 0.6 0.8 1.0
DataGLF23 w/ γ
E
GLF23 w/o γE
DataGLF23 w/ γ
E
GLF23 w/o γE
T (k
eV) Ti
Te
Normalized Radius
#104276t=5.71 s
PROJECTIONS TO ITER ARE UNIFORMLYFAVORABLE AND SUGGESTS IGNITION IS POSSIBLE
263-04/MW/jy
— Use plasma shape, q95, and bN, and Hxx from experiment— 50/50 D-T mix, Zeff prescription from ITER, He ash treated self consistently— Use DIII–D ne, Te profiles, fix Te = Ti— Choose n/nGW = 0.85; tHe / tE = 5; CEJIMA = 0.6
Projections
Primary difference is b scaling:Petty, Fusion Sci. Tech. 43 1 (2003)
H89: b–0.5 H98y2: b–0.9 HDS03: b0
Plasma currentDurationScalingPfusionQfus
q95 = 4.5
10.3 MA3900 s
H894409.0
H98y24408.9
HDS03370•
q95 = 3.2
*
13.9 MA1900 s
H8978012.9
H98y274039
HDS03700•
S A N D I E G O
DIII–DNATIONAL FUSION FACILITY
Projection Methodology:
* *
*
S A N D I E G O
DIII–DNATIONAL FUSION FACILITY
● Stationary, high normalized performance operation has been demonstrated on DIII–D over a wide range in operating space.
q95 = 3.2: G = βNH89/q95 > 1.4 GITER for > 9 τR
q95 = 4.5: G ≈ GITER for > 4 τR
SUMMARY
263-04/jy
2
● Projections are uniformly favorable for ITER and suggest the possibility of very high fusion gain (possibly Qfus = ∞) operation as well as long pulse, Qfus > 5 operation in ITER
● Stability and confinement characteristics are similar to that of the conventional, ELMing H-mode case (ITER physics basis is still valid)
— Measurements indicate the importance of a small m=3/n=2 NTM in controlling the current profile to prevent or minimize sawteeth, thereby allowing high β, good confinement operation