overview of jet results
DESCRIPTION
Overview of JET results. Acknowledgements Staff and management from EFDA Associates involved in the JET workprogramme, in particular the JET Task Force Leaders and the Operator of the facility (UKAEA) European Commission International collaborators: U.S.A. and Japan. JET EFDA Contributors - PowerPoint PPT PresentationTRANSCRIPT
IAEA Conference J. Pamela Lyon, 14 October 2002
Overview of JET results
JET EFDA Contributors
presented by J. Pamela
Acknowledgements
Staff and management from EFDA Associates involved in the JET workprogramme, in particular the JET Task Force Leaders and the Operator of the facility (UKAEA)
European Commission International collaborators: U.S.A. and Japan
IAEA Conference J. Pamela Lyon, 14 October 2002
JET divertor configuration 2000-2002
Septum removed by remote handling: Mk-IIGB to Mk-IISRP
Up toApril 2001
2002onwards
Increased triangularity
Increased range of ITB
plasma configurations
IAEA Conference J. Pamela Lyon, 14 October 2002
Content of the talk
H-mode ELMs physics / ELM extrapolation to ITER MHD and kinetic effects on H-mode performance H-mode performance / consolidation of ITER reference scenario
Advanced Tokamak AT Physics AT performance Real time control
Erosion and co-deposition Future plans
IAEA Conference J. Pamela Lyon, 14 October 2002
ELMs: high pedestal density reduces power transients at ITER shaping
High and high npedestal leads to softer and less frequent ELMs(mixed type I - type II)
Other “recipes” for access to softer ELMs:- impurity seeding- high Pin/PLH at moderate (~0.3)
J.Ongena, EX/C2-4 A.Loarte, EX/P1-08
IAEA Conference J. Pamela Lyon, 14 October 2002
Extended/improved data base for Type I ELMs extrapolation (2 examples)
WELM scales with *ped
Loarte, EX/P1-08 Matthews, EX/D1-1
4 6 8 10
ne / 1019m -3
0
0.02
0.04
0.06
0.08
Wta
rget
/ W
pla
sm
a
to ta linnerouter
ELM energy is balanced in/out in JET
even ELM energy distribution
optimal for ITER
IAEA Conference J. Pamela Lyon, 14 October 2002
The improved/extended data base allows revised predictions assuming JET data extrapolate to ITER:
Tolerable ELMs (C or W) Wmax = 4 to 19 MJ
Type I-ELM size predictions WELM = 10 to 20 MJ
=> hope that Type I ELMs may be tolerable
Matthews, EX/D1-1 Loarte EX/P1-08
Type I- ELM revised extrapolation to ITER
IAEA Conference J. Pamela Lyon, 14 October 2002
MHD and kinetic effects -particle simulation experiment in ELMy H-mode
• evidence from emission from nuclear reaction 9Be(,n)12C • fast ’s provide up to 80-90% of plasma heating • long sawteeth stabilised by s leading to NTMs
Multi-MeV acceleration of 120keV 4He beam ions by 3rd harmonic ICRH
caveat: these ’s are not isotropic in contrast to DT fusion born ’s J.M. Noterdaeme, EX/W-1Mantsinen et al., PRL 88 (2002)
Kiptily, NF 42 (2002)
IAEA Conference J. Pamela Lyon, 14 October 2002
NTM Controlsawtooth control by ICRH raises N NTM onset
• Long period sawteeth (due to ICRH) allow NTMs to be destabilised at any BT
• used to extend parameter domain towards ITER
• typical H-modes in JET are metastable to NTMs (and * scaling predicts this to be the case in ITER)
• Conversely ICRF heating and current drive near q=1 modifies sawteeth and raises N for 3/2 NTM onset relative to NBI only caseSauter, PRL 2002 Hender, EX/S1-2
IAEA Conference J. Pamela Lyon, 14 October 2002
ITER-like plasma shape
ELMy H-modeConsolidation of ITER reference operationBeneficial effect of triangularity
G. Saibene, PPCF 2002
Ongena, EX/C2-4
Higher edge pressure gradient accessible at high (MHD modelling by G.T.A. Huysmans, EFPW 2001)
IAEA Conference J. Pamela Lyon, 14 October 2002
HH
AUGJET
Further ELMy H-mode studies to be driven by scientific issues :- understanding experimental differences (details of magnetic configuration ,
q etc.; ELM behaviour etc.)- identifying physics-based scaling parameters for high density operation- interrelation edge/core/details of plasma configuration/collisionality
=0.29=0.47
ELMy H-mode / future workIncreased confidence in ITER operation at H~1 and n/nGW>0.85
Ongena, EX/C2-4Gruber, NF 41 (2001)
IAEA Conference J. Pamela Lyon, 14 October 2002
Content of the talk
H-mode ELMs physics / ELM extrapolation to ITER MHD and kinetic effects on H-mode performance H-mode performance / consolidation of ITER reference scenario
Advanced Tokamak AT Physics AT performance Real time control
Erosion and co-deposition Future plans
IAEA Conference J. Pamela Lyon, 14 October 2002
Advanced Tokamak reliable tuning of shear reversal by LHCD providing easy access to ITBs
Challis PPCF 44 (2002)Hawkes PRL 87 (2001)
Litaudon, EX/C3-4
IAEA Conference J. Pamela Lyon, 14 October 2002
Advanced Tokamak Current Hole observation and modelling
20-40 cm wide core region has j(r)=0 (error bars ± 10-20 kA)
Modelling: Although off-axis co-LHCD is sufficient to drive negative current near axis, repetitive m=1, n=0 modes would ‘clamp’ current to zero
Hawkes, PRL 87 (2001), Huysmans, PRL 87 (2001), Stratton, PPCF 44 (2002)Miura EX/C3-1Ra, Stratton EX/C3-1Rb
IAEA Conference J. Pamela Lyon, 14 October 2002
Advanced Scenarios link between rational q surfaces and ITBs
Transport barriers appear/develop when qmin crosses rational q surfaces
The time when qmin crosses rational surfaces is confirmed by the excitation of Alfven cascades
Garbet TH/2-1Joffrin EX/P1-13
Pulse 51573. JET ITB criterion from electron temperature (ECE)
*T
0.014
0.016
0.018
0.020
0.022
n=1 m=2 mode
4.5 5 5.5 6 6.5 7 7.5
3.2
3.3
3.4
3.5
3.6
3.7
Time (s)
s>0
s<0
q=2Major Radius [m]
5MW ICRH + 11.5MW NBI
MHD n=1 component [a.u.]
qmin
‘narrow’ ITB in thes<0 region
q=2 locationfrom the MHDanalysis [38]
IAEA Conference J. Pamela Lyon, 14 October 2002
3
n=2
45
534
45
55
n=2
Alfvén Cascades observed in ITB plasmas (c.f. JT60-U) and modelled
Indication of q(r) evolution from TAE antennas:
diagnostic for qmin evolution in ITB plasmas (use of TAE antennas demonstrated for monotonic q profiles)
Jaun, CT/P-06, Breizman TH/4-3, Zonca TH/4-4
Advanced Scenarios Alfvén cascades as signature of q(r) evolution
Borba, NF 42 (2002)
IAEA Conference J. Pamela Lyon, 14 October 2002
Advanced Scenarios Feasibility Demonstration of Pressure Profile Real Time Control
Real time feedback loop on neutron rate controlled by NB Te-profile controlled by ICRH
3.0
2.0
1.0
0
6
4
2
01.2
0.8
0.4
0
12108642Time [s]
15
10
5
01.2
0.8
0.4
0
Active control
Ip[MA]
#53697
PNBI
PICRH
Vs [V]
PLHCD[MW]
MW
1016 neutron/s
s/Lte (x10-2)
Reference
Reference
Mazon, PPCF 44 (2002)Litaudon, EX/C3-4Joffrin EX/P1-13
IAEA Conference J. Pamela Lyon, 14 October 2002
Advanced Scenarios Current Profile Real Time Control
Real-time control of plasma current profile measurement by
polarimetry acting on LHCD
Litaudon, EX/C3-4
IAEA Conference J. Pamela Lyon, 14 October 2002
A.T. Summary“Long pulse ITB” “high performance ITB” ITER-AT[JET #53521 t=10s] [JET#51976 t=6.8s] Q=5
H H (IPB98y-2) 1 1.9 >1.5
H ITER 89 L-P 2.1 3.3
N 1.7 2.4 >3.0
nel/nGreenwald 0.5 0.35 0.6-1
INon-Inductive/Ip 90% 55% 100%
Iboot/Ip 50% 40% >60%
q95 5.5 4.9 4.5
Prad/Ptot 23% 15% 75%
/E. 27 2 >100
Edge type III ELMs type III ELMs soft ELMs
=> progress … but still significant efforts needed: higher density / long pulse high
performance / impurity control / simultaneous pressure and current profile control
IAEA Conference J. Pamela Lyon, 14 October 2002
Content of the talk
H-mode ELMs physics / ELM extrapolation to ITER MHD and kinetic effects on H-mode performance H-mode performance / consolidation of ITER reference scenario
Advanced Tokamak AT Physics AT performance Real time control
Erosion and co-deposition Future plans
IAEA Conference J. Pamela Lyon, 14 October 2002
Erosion / Deposition Tile Analysis (MkII-GB divertor)
Analysis of tiles removed during Shutdown 2001: clear deposition in inner divertor (co-deposited layers) almost no deposition in outer divertor Deposited material is mostly from main chamber erosion
=> Confirm results from tile analysis with the more open MkII-A divertor
IAEA Conference J. Pamela Lyon, 14 October 2002
louvre
Quartz monitor
Measured deposition rate much lower than concluded from Deuterium-Tritium experiments in 1997 : possible reasons
- strike point position (identified to be very important )
- lower density plasmas with larger ELMS in 1997- reduced operating T: V-vessel from 300 to 200ºC tiles from 200 to 100ºC (effect tbc)
- QMB at 100ºC while divertor louvres are water cooled V.Philipps, EX/P5-08
0 1x1025 2x1025 3x1025 4x1025
0
4x1017
8x1017
1x1018
To
tal d
epo
siti
on
(C
/cm
2 ) Total ion flux during exposure (inner)
0.00
0.04
0.08
0.12
To
tal c
arb
on
on
lou
vre
area
(g
)
0.1 m
80 shots
Erosion / Deposition shot by shot deposition measurement with Quartz Microbalance
IAEA Conference J. Pamela Lyon, 14 October 2002
Limited Physical Erosion
and Deposition
DepositionChemical Erosion
Net Erosion,physical and
chemical
Erosion / Deposition Plasma flow in SOL transports carbon to divertor inner target
Mach Probe
tile analysisQMB
IAEA Conference J. Pamela Lyon, 14 October 2002
Content of the talk
H-mode ELMs physics / ELM extrapolation to ITER MHD and kinetic effects on H-mode performance H-mode performance / consolidation of ITER reference scenario
Advanced Tokamak AT Physics AT performance Real time control
Erosion and co-deposition Future plans
IAEA Conference J. Pamela Lyon, 14 October 2002
Near Term Plans Experimental Campaigns until February 2004,
including a Trace Tritium Campaign 2004 shutdown:
new/upgraded diagnostics ICRH ITER-like antenna => High Power Density
ICRH coupling / ELM-resilience modified divertor (ITER-like in an extended
range of Ip/BT ; increased power handling)
ITER like antenna / Resonant Double Loop Concept from ORNL and CEA
IAEA Conference J. Pamela Lyon, 14 October 2002
Conclusion ELMy H-mode
revised Type I ELMs predictions / hope that Type I ELMs be tolerable on ITER possible paths to alternate / softer ELMy regimes compatible with high HH
progress in NTM physics and control (sawtooth / ICRH) new tool for alpha particle studies available (4He acceleration by ICRH) consolidation of ITER operating scenario HH ~1 and n/nG>0.85 at ITER relevant (~0.5),
q95(~3) in relevant Zeff range (1.5-2.0) Advanced Modes
LHCD provides easy and reliable access to Reversed Shear and control of off-axis current in long pulses
Current Holes observed in R.S. / Transport & MHD models developed Rational q surfaces play a key role in ITB formation/development Alfvèn cascades in R.S. plasmas: promising tool for q(r,t) diagnostic Real Time control of pressure profile demonstrated Real Time control of current profile demonstrated
JET remains a key asset with unique features in preparation of ITER Operation (ITER scenarios / test of ITER auxiliaries prototypes)
IAEA Conference J. Pamela Lyon, 14 October 2002
JET papers at this confrence LOARTE "Type I ELM energy and particle losses in JET ELMy H-modes and implications for ITER", EX/P1-08
MATTHEWS .,"Steady state and transient power loads in JET", EX/D1-1
RAPP "Reduction of divertor heat load in JET ELMy H-modes using impurity seeding techniques", EX/P1-09
PARAIL "Integrated Modelling of JET H-mode Plasmas with type-I ELMs", TH/P3-08
KOSLOWSKI "Observation of Pre- and Postcursor Modes of Types I ELMs on JET", EX/P1-14
LITAUDON "Progress towards steady state operation and real time control of ITBs in JET", EX/C3-4
HENDER "Sawtooth, Neo-Classical Tearing Mode and Error Field Studies in JET", EX/S1-2
ONGENA "Towards the realization on JET of an integrated H-Mode scenario for ITER", EX/C2-4
TESTA "Experimental Study of the Stability of Alfven Eigenmodes on JET", EX/P1-17
NOTERDAEME "Heating, current drive and energetic particles studies on JET ...", EX/W-1
MANTICA "Transient Heat Transport Studies in JET Conventional and Advanced Tokamak Plasmas", EX/P1-04
GARBET "Micro-stability and Transport Studies of Internal Barriers in JET", TH/2-1
JOFFRIN "Internal Transport Barrier triggering by rational magnetic flux surfaces", EX/P1-13
DUX "Impurity transport in internal barrier discharges on JET", EX/C3-5Ra
PHILIPPS "Recent results on long term fuel retention in JET and TEXTOR and predictions for ITER", EX/P5-08
SUTTROP "Parameter similarity studies in JET, ASDEX Upgrade and ALCATOR C-Mod", EX/P5-07
HIDALGO "Experimental evidence of fluctuations and flows near marginal stability ...", EX/C4-4
STRATTON "Equilibria and Stability of JET Discharges with Zero Core Current Density", EX/C3-1Rb
(see talk by Miura, EX/C3-1Ra)
CASTALDO "Transport barriers produced in JET discharges by ion Bernstein waves", post-deadline
JAUN "Collective modes and Fast Particle Confinement in ITER", CT/P-06
ASAKURA "Studies of ELM heat load, SOL flow and carbon erosion ..." , CT/P-01
BREIZMAN "Alfven Eigenmodes in Shear Reversed Plasmas", TH/4-3