Experimental Results of IBW heating on the HT-7

Chengming Qin, Yanping Zhao, Weici Shen, Haiqian Liu, Bo lv, Guosheng Xu, HT-7team

Institute of Plasma Physics, Chinese Academy of Science, Hefei, China

ASIPP HT-7

Abstract

An Ion Bernstein wave heating experiments using different frequency (27MHz and 30MHz) was carried out on HT-7 in the recent IBW experiment. At 30MHz, ne peaked and Hа dropped have been pervasive observed, P was improved factor of 2-3. Energy confinement was improved by factor of 1-1.5. Obviously confinement of particle was observed during the IBW pulse.At 27MHz, by choosing layer location, the globe and localized heating phenomena can be observed, Central electron heating effect was obtained in the global heating mode and electron temperature strongly increased near the 2ΩD resonant layer for localized heating .

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content

• ICRF system

• IBW system

• At 30MHz IBW heating experiment

• At 27MHz IBW heating experiment

• Summary

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ICRF Heating System in HT-7 Tokamak

IBW System

Frequency: 0~30MHzRF Power: 0~350kWRF Pulse length: CWMatching System: Two Stub-tunersT-type Antenna: Area:(490+150)cm2

n||: Peaked at 8 for 27 MHz

Central conductor: TiN coatingShielding and side protector: graphite

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IBW heating with 30MHz

0.0 0.2 0.4 0.6 0.80

1

0.0 0.2 0.4 0.6 0.8

0.1

0.0 0.2 0.4 0.6 0.80

100

0.0 0.2 0.4 0.6 0.80

100

0.0 0.2 0.4 0.6 0.80

1

2

I_sx e

Ha d

PIB

W(k

w)

c

I P(k

w)

a

Ne(1

019

m-3

b

PRF~160kW, Bt=1.95T,Ip=150kA

-1.0 -0.5 0.0 0.5 1.0-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Ne

(10

19m

-3)

r/a

300ms 500ms 600ms 700ms 760ms

Significant improvement of particle confinement was observed

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Before IBW powerτp~5ms,after

injection IBW, τp~15ms,increased by factor

of 2-3

IBW heating with 27MHz

global heating:. BT=1.9T, rH ~ 3.9cm

-1.0 -0.5 0.0 0.5 1.0

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Ne

(10

13cm

-3)

r/a

0.4s0. 5s 0.9s 1s 1.2s 1.4s

0.0 0.5 1.0 1.5 2.0

0.0 0.5 1.0 1.5 2.00.0

0.20.0 0.5 1.0 1.5 2.0

0

200

0.0 0.5 1.0 1.5 2.00

150

0.0 0.5 1.0 1.5 2.00

10.0 0.5 1.0 1.5 2.00

0.0 0.5 1.0 1.5 2.00.01.5 a

r=3cm

Te(k

ev)

Ha

PIB

W(k

w)

f

b

I P(k

A)

c

ne

(10

19 m

-3 )

e

I_sx

d

r=12cm

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The electron temperature Te in the location r= 3cm > Te in the location r= 12cm in IBW heating phase,the maximum electron temperature reached to about 2.4kev .Central electron heating effect was observed.

27MHz IBW heating

Localized heating :BT=2.0T, rH ~ 10cm

0 200 400 600 800 1000-1

0

1

2

3

4

5

6

7

8

9

p(m

s)time(ms)

Ha andτp almost

unchanged. No particle confinement observed

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0.0 0.2 0.4 0.6 0.8 1.00

1

0.0 0.2 0.4 0.6 0.8 1.00.1

0.2

0.0 0.2 0.4 0.6 0.8 1.00

150

0.0 0.2 0.4 0.6 0.8 1.00

150

0.0 0.2 0.4 0.6 0.8 1.001

0.0 0.2 0.4 0.6 0.8 1.00.0

0.5

0.0 0.2 0.4 0.6 0.8 1.0

r=12cm

Te(

kev)

Ha

PIB

W(k

w)

f

d

c

e

I P(k

A)

Ne(1

019

m-3

)

b

r=6cm

I_sx

r=6cm

a

The electron temperature Te in the location r= 12cm > Te

in the location r= 9cm in IBW heated phase

27MHz IBW heating

•Ne increased and peaked

• Te globally increased only around the H layer

•Localized heating was obtained

-1.0 -0.5 0.0 0.5 1.0

0.0

0.5

1.0

1.5

2.0

2.5

ne

(1

01

9 m

-3 )

r/a

350ms 450ms 550ms 650ms 750ms

0 5 10 15 20 25

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Te

(ke

v)

r(cm)

IBW OH

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Summary In this IBW experiment , we mainly obtained these exp

erimental results:• For30 MHz, Particle confinement obvious improvemen

t and strongly increased and very peaked density profile were observed.

• For 27 MHz, both global and localized electron heating’ phenomena were observed by changing the location of the 2 ΩD resonant layer.(a) Central electron heating effect was obtained in the global heating mode on the HT-7 Tokamak. (b)Electron temperature strongly increased near the 2ΩD resonant layer for localized heating was observed. There is no obviously improvement of particle confinement in the localized heating modes.

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reference

1.Ono, M., Phys. Fluids B 2 (1993) 2412.Biglari H., Diamond P.H. and Terry P.W. 1990

Phys. Fluids B 2 13.L. A. Berry, E. F. Jaeger, and D. B. Batchelor, Phys. R

ev. Lett. 82, 18714. B. LeBlanc, R. E. Bell, S. Bernabei et al., Phys. Rev. L

ett. 82, 331 ~1999!.5. Zhao,Y, et al., 19thIAEA Fusion Energy Conference, I

AEA-CN-77/EXP4/30, 14–19 Octo-ber 2002, Lyon, France ~International Atomic Energy Agency, Vienna, 2003).

6. Baonian Wan, et al., Physics of Plasma 9(2003) 3703-3711

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