introduction of 6 th steady state operation itpa topical group meeting x.d. zhang 8-10 november,...
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Introduction of6th Steady State Operation ITPA Topical Group Meeting
X.D. ZHANG
8-10 November, 2004IST, Lisbon, Portugal
66thth SSO ITPA Meeting SSO ITPA Meeting
Participants (28/10/04)
US
Tim Luce luce@fusion.gat.com
Peter Politzer politzer@fusion.gat.com
Ron Prater prater@fusion.gat.com
Roger Raman raman@aa.washington.eduRandy Wilson jrwilson@pppl.gov
EU
Claude Gormezano gormezano@frascati.enea.it
Rob Akers rob.akers@ukaea.org.uk
Alain Becoulet alain.becoulet@cea.fr
Gerardo Giruzzi gerardo.giruzzi@cea.fr
Didier Moreau Didier.Moreau@jet.efda.org
JM Noterdaeme jmn@ipp.mpg.de
George Sips ccs@ipp.mpg.de
Angelo Tuccillo tuccillo@frascati.enea.it
66thth SSO ITPA Meeting SSO ITPA Meeting
New membership
EU: A.Becoulet, C.Gormezano, A.C.C.Sips, A. Tuccillo
Japan: S.Ide, A.Fukuyama, K. Hanada, T.Suzuki, Y.Takase,
Y.Nakamura
RF: V.Kulygin,V.Vdovin, A.Zvonkov
US: C.Philips, P.Bonoli, C.Forest, W.Heidbrink, R.Prater China: X.Gong, X. Ding, X. Zhang, X.Song, J.Luo
Korea: K.I.You, Y.S.Na, J.M.Kwon
ITER: T.Oikawa
up to 9 November 2004
Chair&co-chair: C. Gormezano & S. Ide
after 9 November
Chair&co-chair: A.C.C. Sips & S. Ide
66thth SSO ITPA Meeting SSO ITPA Meeting
Participants (28/10/04)
Japan
Shun Ide ide@naka.jaeri.go.jp
Kazauaki Hanada hanada@triam.kyushu-u.ac.jp
Yukio Nakamura nakamura.yukio@LHD.nifs.ac.jp
Hiroschi Idei idei@triam.kyushu-u.ac.jp
Yuichi Takase takase@plasma.phys.s.u-tokyo.ac.jp
Takahiro Suzuki suzukit@fusion.naka.jaeri.go.jp
Atsushi Fukuyama fukuyama@nucleng.kyoto-u.ac.jp
China
Xiaodong Zhang xdzhang@ipp.ac.cn
ITER
Toshihiro Oikawa toikawa@naka.jaeri.go.jp
66thth SSO ITPA Meeting SSO ITPA Meeting
Charter for the: Steady-State Operation Topical Group
Explore the potential for achieving integrated scenarios for steady state operation in a burning plasma experiment:
• Scenarios for steady-state operation and maximising fusion energy produced
• Control systems (NB, ICH, ECH, LH, fuelling, pumping, ……• Applicability, feasibility and compatibility of heating and current
drive, fuelling, particle exhaust and angular momentum injection systems, for integrated operation in ITER.
• Steady state burning plasma conditions and techniques for current profile, density, and performance control (beta, fusion power….).
66thth SSO ITPA Meeting SSO ITPA Meeting
S. Ide: IAEA Highlights on Steady State scenarios
T. Luce: IAEA Highlights on Hybrid scenarios
Joint meeting with Transport Group on Joint experiments
(SSOEP1 & SSOEP2): achieved results
JT-60U (S. Ide)
AUG (G. Sips)
DIII-D (T. Luce)
JET (X. Litaudon)
Joint meeting with Transport Group on Joint experiments
(SSOEP1 & SSOEP2): proposals for new experiments,
fill in the bullets
66thth SSO ITPA Meeting SSO ITPA Meeting
Heating & Current Drive
R. Prater: IAEA Highlights on Heating &CD
H. Idei: Initial results on ECCD hardware experiments on TRIAM-1M
R. Prater: Status report on ECCD code benchmarking
E Joffrin: IAEA Highlights on Control Issues
D. Moreau: Control of ITBs on JET
T. Suzuki: real time control of j(r) in JT-60U
Joint meeting with Pedestal Group
G. Sips: Pedestal issues in Steady state and hybrid scenarios
66thth SSO ITPA Meeting SSO ITPA Meeting
(distance between the two separatrices at the midplane of diverted plasmas) organised by R. Stambaugh
AUG L. Horton or A. Kallenbach
DIII-D E. Strait
JT-60U N. Asakura
C-MOD A. Hubbard
MAST H. Meyer
NSTX R. Maingi
66thth SSO ITPA Meeting SSO ITPA Meeting
Joint meeting with Modelling group: presentations
R. Budny: simulation of heating &CD in ITER
A. Becoulet: latest ITER current profile simulation for ITER with
CRONOS
A. Fukuyama: latest ITER current profile simulation for ITER with TASK
M. Murakami: latest current profile simulation for ITER with ONETWO
Joint meeting with Modelling group: Nuclear Fusion paper
Steady state operation
K. Hanada: Impurity accumulation and expulsion in a TRIAM-1M long
pulse discharge
P. Politzer: Is a “steady-state" plasma necessarily stationary?
66thth SSO ITPA Meeting SSO ITPA Meeting
From JT-60U:Integrated performance <=> the ITER steady state domain
ITER_SS(I)E44104_8.3s
Prad
/Pheat
ne/n
GW
HHy2
N
fBS
fCD
fuel purity
1.32.56
0.5
1
0.770.56
0.83
Shall we add items:PedestalImpurity accumulationDivertor compabilityOthers?
Integration: meaning?
66thth SSO ITPA Meeting SSO ITPA Meeting
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J T - 6 0 U
C u r r e n t p r o f i l e c o n t r o l
O b j e c t i v e o f c u r r e n t p r o f i l e c o n t r o l
o b t a i n b e t t e r c u r r e n t p r o f i l e f o r h i g h e r s t a b i l i t y & c o n f i n e m e n t
m a i n t a i n j ( r ) r o b u s t t o p e r t u r b a t i o n
J T - 6 0 U s t a r t e d j ( r ) c o n t r o l e x p . i n 2 0 0 4 .
C o n t r o l b y o f f - a x i s c o - C D , i n c o m b i n a t i o n w i t h o n - a x i s O H c u r r e n t
U s e o f c o - C D c o m p a t i b l e t o i n c r e a s i n g f C D
N o t s t r o n g l y s p e c i f i c t o c u r r e n t d r i v e r
B a s i c i d e a i s t o d e c r e a s e t h e l a r g e s t r e s i d u a l i n q , n o t t o d e c r e a s e a n a v e r a g e d r e s i d u a l .
66thth SSO ITPA Meeting SSO ITPA Meeting
J T - 6 0 U
q p r o f i l e c o n t r o l ( q ( 0 ) ~ 1 1 . 3 ) w a s d e m o n s t r a t e d .
w a s c o n t r o l l e d .
q ( r ) a p p r o a c h e d t o t h e r e f e r e n c e a t t = 1 3 s , a n d w a s s u s t a i n e d f o r 3 s .
n e = 0 . 5 x 1 0 1 9 m - 3
C D ~ 1 x 1 0 1 9 A / W / m - 2
R e f l e c t i o n r a t e ~ 5 %
66thth SSO ITPA Meeting SSO ITPA Meeting
66thth SSO ITPA Meeting SSO ITPA Meeting
66thth SSO ITPA Meeting SSO ITPA Meeting
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20
Experiments in 2004 at ASDEX-U
AIMS:
• q-profile evolution in Hybrids, and MHD.
• Operation at 600kA/1.4T and 1.2MA/2.8T.
• Variation in q95 (and density) in collaboration with DIII-D.
• ICRH heating with PICRH > PNBI
21
Physics:• Scaling of the confinement with and * and stability (*,MHD).• Document the edge of the plasma.• Scaling to ITER.• Operation at high density, small ELMs ?
Scenario development:• Use of ICRH, towards on RF only demonstration.• Use of ECCD for q-profile and MHD control.
• Demonstrate at q95 ~3 or lower.
• Assess operation at low density with increased W surface.
Integration:• ELM control techniques with improved confinement.• International collaboration.
Still to be done on ASDEX-U.....
66thth SSO ITPA Meeting SSO ITPA Meeting
Joint experiment 2005 Steady-State Operation
current profile
q profile
high bootstrap (fBS70%) fraction
ITBs at large radius
Te/Ti effect on confinement
q and density
compare effects of tearing mode, fishbones,
and sawteeth
compare profile control techniques for SSO
JET, JT-60U, ASDEX-U, DIII-D
ASIPP ASIPP HT-7 HT-7
Experiments of full non-inductivecurrent drive on HT-7
X.D. Zhang, Z.W. Wu, Z.Y. Chen, X.Z. Gong, H. WangD. Xu, Y. Huang, J. Luo, X. Gao, L. Hu, J. Zhao
B.N. Wan, J. Li and HT-7 Team
Institute of Plasma Physics, Chinese Academy of Science
Hefei, 230031, CHINA
E-mail: xdzhang@ipp.ac.cn
20th IAEA Fusion Energy Conference, 1-6 November, 2004, Vilamoura, Portugal
ASIPP ASIPP HT-7 HT-7 AbstractAbstract
• Steady-state operation is a main goal, three types of experiment are used to study long pulse discharge, steady-state operation and full non-inductive current drive on HT-7.
• The results show that the plasma current in the full non-inductive current drive case is instable due to no compensation of OH heating field or self-induction loop voltage, this instability of plasma current will increase the interaction of plasma with limiter and first surface and bring impurity.
• All discharges of full non-inductive current drive are terminated because of impurity spurting.
• To adjust the LHW power for control the loop voltage during long pulse discharge is the most effective method for steady-state operation on HT-7.
ASIPP ASIPP HT-7 HT-7 Long pulse operations on HT-7Long pulse operations on HT-7
HT-7 Superconducting Tokamak R=1.22m a=0.27m BTmax=2.2T Ipmax =250KA ne=1.0~5.0x1019
m-3 Temax = 4 KeV Timax = 1.5 KeV
Bottom, top and high field side toroidal limiters
LHW systemMulti-junction grill type, 3 rows and 4x4 columns of waveguid
es,Nll=1.25~3.45, fLHW=2.45GHz, PLHWmax=1.2MW
Parameters for long pulse operationIP=50~60KA BT=1.8~2.0T neo=1.0x1019m-3 Te=0.5KeV
PLHW =100~400KW fLHW=2.45GHz Nll=2.35
ASIPP ASIPP HT-7 HT-7 Long pulse operations on HT-7Long pulse operations on HT-7
Three types of long pulse operation on HT-7 tokamak
The first type: long pulse dischargePlasma current droved by LHW + a fraction of OH current
The second type: steady-state operationPlasma current droved by LHW + to control VL~ 0
The third type: full non-inductive current drivePlasma current droved by LHW + without OH heating field
ASIPP ASIPP HT-7 HT-7 Type I: Long pulse dischargeType I: Long pulse discharge
Plasma current droved by LHW + a fraction of OH current
1. A little of loop voltage supplies fraction plasma current in high performance long pulse discharge.
2. Because of the limit of volt-second, the discharge will be terminated when the magnetic flux in iron core saturate.
3. In this case, the pulse length is limited, so which cannot be called as steady state operation.
4. The effect of OH heating field determines the operation state in long pulse discharge.
ASIPP ASIPP HT-7 HT-7 Type II: Steady state operationType II: Steady state operation
Plasma current droved by LHW + to control VL~ 0
• It is difficult to keep VL close to zero with constant PLHW.
• In a high-performance tokamak for steady-state operation, a turbulence of plasma or LHW system is not unavoidable.
• Steady-state operation need to adjust PLHW during discharge.
• A feedback control system of PLHW based on DEF signal (volt-second) is developed on HT-7, which will be used to reduce the compensation of OH heating field.
• The OH heating field only in a short time supplies some compensation, after the PLHW is adjusted and which can sustain the plasma current, the OH heating field will return to the initial value.
ASIPP ASIPP HT-7 HT-7 Type II: Steady state operationType II: Steady state operation
A degraded driving effect due to small density fluctuation can be compensated by OH heating field and increase PLHW.
Shot: 71349 shot: 71513
ASIPP ASIPP HT-7 HT-7 Type II: Steady state operationType II: Steady state operation
The adjust value cannot be large, to the larger turbulence which is also powerless and
the discharge will be terminated quickly.
Shot: 71349 shot: 71513
ASIPP ASIPP HT-7 HT-7 Type III: Full non-inductive current driveType III: Full non-inductive current drive
Plasma current droved by LHW + without OH heating field
“Genuine” non-inductive current drive
There are two phases in this case, normally the current droved by LHW is larger than the plasma current.
Phase I: negative VP, reverse compensating plasma current supplied by OH heating field to keep a constant IP.
Phase II: “genuine” non-inductive current drive, VP ~ 0, IOH ~ 0, saturated magnetic flux, no multi and self-induction.
ASIPP ASIPP HT-7 HT-7 Type III: Full non-inductive current driveType III: Full non-inductive current drive
• From phase I to II, the IP increase quickly in a short time (~4s) due to without multi and self-induction, or reverse compensating plasma current.
• The HX profile shows a off-axis deposition of LHW power in phase I and on-axis deposition in phase II on HT-7.
ASIPP ASIPP HT-7 HT-7 Type III: Full non-inductive current driveType III: Full non-inductive current drive
in “genuine” non-inductive current phase
without OH heating field and self-induction loop voltage
fluctuation of plasma parameters and LHW power
instability of plasma current and profile
interaction of plasma with limiter and first wall bring impurity or plasma density rise
unfavorable for current drive
ASIPP ASIPP HT-7 HT-7 Type III: Full non-inductive current driveType III: Full non-inductive current drive
The impurity signal of CV shows that the CV radiation layer is consistent with the deposition region of LHW power and the C impurity
will accumulate gradually in phase II on HT-7 (shot: 61576).
4s 18s7x10-3 1.7x10 -2
38s 51s2.2x10-2 2.8x10 -1
ASIPP ASIPP HT-7 HT-7 Type III: Full non-inductive current driveType III: Full non-inductive current drive
Non-inductive current drive without OH heating fieldconstant IOH without OH heating field
self-induction VL can retard the change of plasma current Actually which supplies a fraction of compensating current
shot: 72245 shot: 70208
ASIPP ASIPP HT-7 HT-7 ConclusionConclusion
• On HT-7 the LHW power can be adjusted by means of feedback control system according to the change of DEF signal (Volt-Second) during discharge.
• Because of a small adjusting value, that is powerless for a larger fluctuation. The fluctuations on HT-7 are only impurity and plasma density in steady-state operation.
• The experiments of constant IOH show that the self-induction loop voltage cans also stabilize a larger fluctuation and retard a sudden change of plasma current in short time.
• To adjust the LHW power for control the loop voltage during long pulse discharge is the most effective method for steady-state operation on HT-7.
ASIPP ASIPP HT-7 HT-7 DiscussionDiscussion
• The “genuine” non-inductive current drive is instable due to without multi and self-induction.
• A fraction of compensating current in short time for steady-state operation is needed, whether the compensating fraction is supplied by OH heating field, or self-induction loop voltage.
• The OH heating field should be allowed to supply some compensating plasma current and keep the stability of discharge when a small plasma fluctuation appears during discharge, which will return to the initial value after fluctuation.
• “Full non-inductive current drive” in full space of time and “inductive one” in local space of time.
• The final goal of steady-state operation is how to sustain a stable discharge with high performances in long time and which will be suitable for operation mode of ITER.
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