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

HL-2A

2nd Asia-Pacific Transport Working Group Meeting

ELM mitigation with SMBI-CJI fuelling in HL-2A H-mode plasmas

C. Y. Chen, L. H. Yao, B.B. Feng, Z. B. Shi, W.L. Zhong, J. Cheng, D. L. Yu, X. R. Duan

Southwestern Institute of Physic2012/05/17

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Outline

• SMBI & CJI• Fuelling deposition area • ELM mitigation

ELM mitigation with SMBI ELM mitigation with CJI

• Summary and discussion

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SMBI & CJI

B C

Solid / liquid

isentrope

gas Pv(T)

A (P0,T0)

P(T)

log

P

log T

The gas expands adiabatically, the flow velocity increases and Mach number continues to increases to M>>1 in the zone of silence.

The gas state changes follow the isentrope, over the saturated vapor pressure line, molecular combined together to clusters in the beam.

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SMBI & CJI

0RS cS P N

Rayleigh scattering and electron fluorescence method to measure the clusters.

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~1ms

~0.8ms

Pressure: 1.65MPaPulse duration: 2 msTemprature: -156℃Delay time: ~1 ms

Pressure: 1.45 MPaPulse duration: 2 msRoom tempratureDelay time: ~ 0.8 ms

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H-mode discharge on HL-2A

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Density profile

15 20 25 30 35 40 45 500

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Shot#14052

r(cm)

ne(1

019m

-3)

RLPMWR, 650msMWR, 350ms

PSep.

HPed~1.251019m-3

LFS

H-mode

Gradient

WPed~2.8cm

Ohmic regime

a=38cm

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Deposition area of SMBI

SMBI parameters for shot 14045 (H-mode) ： P = 1.2 MPa, pulse duration 3 ms, separatrix on r = 37 cm, D particles deposited area around r = 36.5 cm 。

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Deposition area of CJI

15 20 25 30 35 400.5

1

1.5

2

2.5

3

r(cm)

n e(1019

m-3

)

Symbol:reflectometer

t=580ms

t=563ms

Solid line:HCNinterferometer

HL-2A, #16576

• CJI could send particles to the pedestal top.

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ELM mitigation

a b

c Bt ： 1.4 TIP ： 150 ~ 180 kANe ： 1.4 ~ 2.4ECRH ： 1 ~ 1.5 MWNBI ： 0.5 ~ 0.8 MW

ELMs mitigation with SMBI (a) ， CJI (b) ， He SMBI (c).

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ELM mitigation with SMBI

0SMBIELM ELMf f ~ 2-3.5 are achieved.

• Significant change of the ELM signal after SMBI pulse.

• The influence persistence time last longer as the injected particles increasing.

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ELM mitigation with CJI

560 580 600 620 640 660 680 700 720 7400

500

1000

1500

t / ms

1/ EL

M (

Hz)

#16128

ELM frequencyCJI monitor

560 580 600 620 640 660 680 700 720 7400

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

t / ms

Amp.

/ a.u

.

#16128

ELM amplitudeCJI monitor

Multi - CJIPressure: 1.4 MPaDuration: 2 msPower: 1 MW NBI

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The comparison of SMBI and CJI on ELM mitigation

Pressure: 1.1 MPaDuration: 4 msRoom temperature

Pressure: 4 MPaDuration: 0.6 msTemperature: - 156 ℃

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ELM mitigation

540 560 580 600 620 64050

100150200

t (ms)

q div (w

/cm2 ) 0.5

11.5

2

D(

a.u.

)

24

CJI

2.22.32.4

n el(m

-3)

24PI

22.22.4

n el(m

-3)

246

D(

a.u.

)540 550 560 570

0200400

t (ms)

q div (w

/cm2 )

1019 (b1)

(c1)

(a1)

(c2)

(a2)16576

(d1) (d2)

15596

1019 (b2)

460 480 500 520

30405060

t (ms)

Qfil

(wcm

-2)

0.5

1

D(

a.u.

)

2

4

6

SM

BI

2

4

6

SM

BI

0.5

1

1.5

D(

a.u.

)

560 570 580 590 600 610

30

40

50

60

t (ms)

Qfil

(wcm

-2)

2

4H

(a.u

.)

2

46

8

D(

a.u.

)

530 540 550 560 570

406080

100

t (ms)

Qfil

(wcm

-2)

(b2)

15596 Pellet Injection(a3)

(c1)

(b3)

(c3)

(b1)

(c2)

16246 CJI16128(a2)(a1) SMBI

• The heat flux at divertor plate remains the same approximately, the filaments number (2.5 ) increases by 30%.

• Per-ELM filament carried heart flux at the strike-point decreased 27%, 38%, 57%.

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ELM mitigation

• Auto-power spectrum of the particle flux measured by Langmuir probe located near the separatrix indicating that the large scale turbulence structures are significantly suppressed, CJI can trigger more small structures (ELM filament or avalanches).

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Summary and discussion

• CJI could inject deeper and may fuel to the pedestal top in HL-2A.

• Experiment results show that SMBI & CJI fuelling are able to mitigate ELM on HL-2A.

• CJI fuelling has the potential to control ELM on larger fusion device.

• Larger cluster deeper injection?

• CJI benefit from deeper injection for ELM mitigation?

• CJI fuelling have the potential to control ELM on larger fusion devices?

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Thank you for your attention!