overview of experimental results on the hl-2a tokamak · l.w. yan, overview on hl-2a, 23rd iaea...

1L.W. Yan, Overview on HL-2A, 23rd IAEA FEC, 11-16 Oct. 2010, Daejeon, Republic of Korea

HL-2ASWIP

Overview of Experimental Results on the HL-2A Tokamak

Southwestern Institute of PhysicsP. O. Box 432, Chengdu 610041, China

L.W. Yan, X.R. Duan, X.T. Ding, J.Q. Dong, Q.W. Yang, Yi Liu, X.L. Zou, Yong Liu, and HL-2A team


HL-2ASWIP

• Characteristics of ELMy H-mode • Transport study with ECRH

�Particle transport modulated by ECRH �Core transport reduction triggered by ECRH switch-off

• Zonal flows & filament characteristics�Low frequency zonal flows and GAMs�Filament characteristics

• Energetic particle induced modes�Beta-induced Alfvén eigenmode �Beta-induced Alfvén acoustic eigenmode

• SMBI fueling • Summary

Outline


HL-2ASWIP Introduction of HL-2A tokamak•R: 1.65 m•a: 0.40 m•Bt: 2.7 T•Configuration:Limiter, LSN divertor

• Ip: 450 kA•ne: ~ 6.0 x 1019 m-3•Te: ~ 5.0 keV•Ti: ~ 2.8 keV

Auxiliary heating systems:ECRH/ECCD: 3 MW(6×0.5 MW/68 GHz/1 s)modulated: 10~30 Hz; 10~100 %NBI: 1.5 MW/45 keV/2 sLHCD: 1 MW(2 ×0.5 MW/2.45 GHz/1 s)

Fueling systems (H2/D2):Gas puffing (LFS, HFS, divertor)Extruded PI (40 pellets/LFS, HFS)SMBI (LFS, HFS)LFS: f =10~60 Hz, pulse>0.5ms Gas pressure: 0.3-3.0 MPaHFS: f = 1-5 Hz, 0.2-1.0 MPa


HL-2ASWIP Two L-H transitions with SMBI fuelling • ELMs appear at 640 ms with

ne=1.8×1019 m-3 rise for 30 ms • The ELMs H-mode remains for 100

ms and then disappears after the SMBI is turned off

• The WE, ne and Prad rise again after the SMBI fuelling is added at t = 770 ms with ne=1.5×1019 m-3

• The clear ELMs appear at 793 ms with ne~1.7×1019 m-3 and disappear at 851 ms, 8 ms after NBI heating is turned off

• The overall discharge exhibits a series of L-H-L-H-L transitions with SMBI fueling

155165

I p (kA

)

1.52.02.5

n e(m-

3 )

0400800

P(kW

)

100200300

P rad(k

W)

102030

WE (

kJ)

24

SMBI

400 500 600 700 800 9000

0.51

t (ms)

D α div

(a.u.)

0.050.10.15

D α, s

(a.u.)

×1019

(g)

(h)

(f)

(e)

(b)

(d)

(a)shot 11565

ECRH(c) NBI

Y. Huang, EXS/P3-02, Wed. AM


HL-2ASWIP Characteristics of ELMy H-mode

• H-mode achieved by ECRH and NBI• ELM periods are a few milliseconds• Some ELMs have periods of 10-30 ms

with energy loss more than 10 %• Power threshold rises with density drop• Minimum Pth=1.1 MW at ne=1.8×1019 m-3

0123

04812

0400800

0400800

600 700 800 90000.71.4

time (ms)

00.71.4

600 650 700 7500

1

time (ms)

(a)

SMBI→

PNBI(kW)PECRH(kW)

Dα-div

#11565

(b)#11605

Dα-div

←ne(1013cm-3)

Dα-div

#13820

1.2 1.4 1.6 1.8 2.00.8

1.2

1.6

Ptot4 Pth

P (M

W)

ne (1019 m-3)


HL-2ASWIP Density pedestal width

• MW reflectometry and probes for pedestal width• Pedestal density is 1.25××××1019 m-3 with nped/ne = 0.6• Density pedestal width is about 2.8 cm

15 20 25 30 35 40 45 5000.20.40.60.81

1.21.41.61.8

r(cm)

ne(10

19m-

3 )

RLPMWR, 650msMWR, 350ms

PSep.

HPed~1.25×1019m-3

LFS

H-mode

Gradient

WPed~2.8cm

Ohmic regime


HL-2ASWIP Outline• Characteristics of ELMy H-mode • Transport study with ECRH






HL-2ASWIP

Amplitude and phase of density perturbation for the first harmonic modulated by ECRH in limiter (a) and in divertor (b) configurations

• Particle outward convection is observed during pump-out transient phase due to ECRH

• Negative density perturbation propagates much faster than the positive one caused by out-gassing

Particle pump-out during ECRH transient

W.W. Xiao, PRL 104 (2010) 215001X.L. Zou, EXC/P8-20, Fri. PM


HL-2ASWIP Te0 rises after far off-axis ECRH switch off

(a) After far off-axis ECRH switch-off (rdep/a=0.69), the Te0 suddenly rises and remains for a few tens of milliseconds before it drops(b) The Te0 increment appears inside q = 1 surface, corresponding to an ITB formation near q = 1 surface

(b)

0

0.5

1

1.5T e

(eV)

350 400 450 500 550 600 65000.51

1.5

n e(10

19m-

3 )

t(ms)

ECRH

r=-24.2cm

#13593

I II

sawtooth

r=-17.0cm

r=-9.0cm

r=-0.1cm

0

0.5

1

1.5

-35 -30 -25 -20 -15 -10 -5 0

#13593 380ms480ms540ms

T e(ke

V)

r(cm)

ECRH

q=1

(a)


HL-2ASWIP

• Microwave reflectometer power spectrum near q=1 surfaceafter ECRH switch-off is much lower than that before or during ECRH, consistent with Te0 rise

Clear drop in ne0 fluctuation

100 101 102

10-1

100

101

f(kHz)

P(a.u.

)

380ms480ms540ms

#13593

afterECRH

ECRHbeforeECRH

Z.B. Shi, EXC/P8-14, Fri. PM


HL-2ASWIP Outline

• Characteristics of ELMy H-mode • Transport study with ECRH






HL-2ASWIP ZF spectrum variation with PECRH & q(a) Intensities of the

LFZFs and GAMs rise with ECRH power

(b) The LFZF intensities increase but the GAMs decrease when the edge safety factor q decreases from 6.2 to 3.5

K.J. Zhao, EXC/7-3, Fri. AM A.D. Liu, PRL 103 (2009) 095002

1 10 10002468

powe

r(a,u)

f(kHz)

1 10 1000

1

2

3powe

r(a,u)

(a)

(b)

GAM

q=6.2q=5.2

q=3.5

380kW

680kw

GAM

LFZF

LFZF


HL-2ASWIP Radial Er power for zonal flows

(a) The intensity of LFZF power first increases slightly and then sharply rises at ~2.5 cm away from LCFS

(b) The GAM power has a maximum at ~1.5 cm awayfrom LCFS


HL-2ASWIP Large scale structure in SOL

(a) Poloidal and radial sizes are less than 1 cm, measured by poloidal 10-tip and radial 8-tip arrays, separated by 210 cm toroidally

(b) Maximum coherence is 0.91 along a magnetic field line(c) Near zero k// is in line with the interchange mode driven mechanism

J. Cheng, EXD/P3-05, Wed. AM


HL-2ASWIP Filament propagation

• The poloidal-radial images with time interval of 5 µs• Filament poloidal and radial sizes less than 1.0 cm• Two filaments with space of 22 mm and lifetime of 25 µs


HL-2ASWIP

time (ms)

f (kHz

)

200 400 600 800 1000 12000102030

-0.50 0.5

0.5

1

e-BAE

ECRHMir (a.u) NBI

m-BAE

（）a

（）b

（）c

ne (1019 m-3)

TMnoise

1.5 2 2.58

12

16

20

24

Bt/ne1/2

f (kHz

)

a

Bt in [T]ne in [1019 m-3]

BAE excited by energetic electrons

• The e-BAE is observed during ECRH for the first time• Large magnetic island induces m-BAE at t = 1220 ms• The BAE frequency increases with VA• The fBAE is much less than fTAE

W. Chen, EXW/4-4Rb, Wed. PMW. Chen, PRL 105 (2010), accepted

ECRH plasma

• Ip = 160 kA, Bt =1.3 T, qa ≈ 4.0, Ti ≈ 0.85 keV• Te≈1.1 keV, PNBI = 0.4 MW, PECRH = 0.9 MW

( )Shot 10579


HL-2ASWIP BAE correlation with energetic electrons 15

36

HX c

ount

1

0.82.4

time (ms)

f (kHz

)

400 500 600 700 800 90001020304050

20-30

（）f

（）b

（）a

（）c

（）d

30-40

10-20 keV

ECRH ne(1019m-3)

（）e

e-BAE

• Beta-induced Alfvén eigenmode appears when the number of energetic electrons with energy of 10-40 keV is high enough

• The mode number of e-BAE is m/n = -3/-1

Shot 13364• Ip = 320 kA• Bt = 2.4T, • qa ≈ 4.0, • Te ≈ 2.3 keV• PECRH =1.4 MW• X-rays detected by Cadmium-telluride (CdTe)


HL-2ASWIP Beta-induced Alfvén acoustic eigenmode

• BAAE with f = 15-40 kHz identified by frequency up-chirping, consistent with the solution for Alfvén-acoustic continuum

• A clear spectrum splitting is first observed on BAAE

Shot 10391•Ip = 170 kA•Bt = 1.4T, •qa ≈ 4.0, •Te ≈ 1.0 keV•Ti ≈ 0.8 keV•PNBI =0.6 MW

Alfvén-acoustic mode

Tearing mode

Splitting


HL-2ASWIP

0 0.1 0.2 0.3 0.4 0.5 0.60

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

r/a

Ω2

m=2 n=2t=560ms

uncoupled Alfven branch

km-1 acoustic branch

Radial range of BAAE gap

BAAE gap

Yi Liu, EXW/P7-15, Fri. AM

• Alfvén-acoustic coupling continuum (Blue & Green)for HL-2A plasma from numerical solution of ideal MHD equations incorporated both the shear Alfvén (azure) and the acoustic (red) branches.[N.N. Gorelenkov, Physics Letter A 370(2007)]

• BAAE is only observed by SXR in the central region

• BAE can be observed by SXR and Mirnov signals


HL-2ASWIP SMBI fuelling efficiency

(a) SMBI fuelling efficiency from HFS is higher than that from LFS

(b) Fuelling efficiency reduces a little from the HFS but about one half from the LFS for powerful ECRH

• The fuelling efficiency of SMBI is 40~60 % for a limiter configuration and 30-40 % for a divertor configuration

D.L. Yu, EXC/P8-22, Fri. PM

1.0

1.5

2.0n e

( ×1019

m-3

)

400 500 600 700 800 9000.5

1.0

1.5

time (ms)

n e (10

19 m

-3)

w/o ECRH

w/ ECRH

(a)

(b)

δne=0.63 δne=0.76

δne=0.60 δne=0.30

LFS SMBIHFS SMBI

LFS SMBIHFS SMBI PECRH=1.3MW


HL-2ASWIP

New Diagnostics: MSE,ECEI, FIR polarimetry, etc.

Now Under development NBI (MW) 1.5 1.5

ECRH (MW) 3 2LHCD (MW) 1 2

Heating systems:

Hardware development in the near future


HL-2ASWIP Summary• Typical ELMy H-mode was achieved with pedestal width of ~2.8 cm.• Negative density perturbation during ECRH pump-out propagates

much faster than the positive one caused by out-gassing.• The Te0 inside q = 1 surface rises after far off-axis ECRH power switch off, consistent with core turbulence suppression.• The LFZF intensities increase but GAMs decrease when qa drops from 6.2 to 3.5. Both intensities rise with ECRH power. • Near zero k// for plasma filaments is observed along a field line, in agreement with the interchange mode driven mechanism.• BAEs excited by energetic electrons of 10 - 40 keV during ECRH

are observed for the first time.• A core localized BAAE is identified by its frequency up-chirping,

and a clear frequency splitting is first observed.• The SMBI efficiency fuelled from HFS is higher than that from LFS.

It reduces a little but about one half for high power ECRH plasma.


HL-2ASWIP

• K.J. Zhao EXC/7-3, Fri. AM • W. Chen, EXW/4-4Rb, Wed. PM• Q.W. Yang, EXS/P2-20, Tue. PM• Y. Huang, EXS/P3-02, Wed. AM• J. Cheng, EXD/P3-05, Wed. AM• Yi Liu, EXW/P7-15, Fri. AM• Z.B. Shi, EXC/P8-14, Fri. PM• X.L. Zou, EXC/P8-20, Fri. PM• D.L. Yu, EXC/P8-22, Fri. PM

HL-2A Experimental Results presented at this conference


HL-2ASWIP 23rd IAEA FEC, 12 Oct. 2010, Korea, OV4-5

In collaboration withUniversity of Science and Technology of China, Hefei, ChinaASIPP, Hefei, ChinaCEA, IRFM, Cadarache, FranceMPI für Plasmaphysik, GermanyNIFS, Toki, Japan Kyoto University, Kyoto, JapanAcknowledgementsGA, PPPL, LLNL, UCI, UCLA, UCSD, USAJAEA, Kyushu U., JapanENEA, Frascati, ItalyIPP-Juelich, GermanyKurchatov Institute, RussiaFOM-Institute for plasma physics Rijinhuizen, Netherlands HUST, IOP, Tsinghua University, China


HL-2ASWIP

Thank you for your attention !

overview of experimental results on the hl-2a tokamak · l.w. yan, overview on hl-2a, 23rd iaea...

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