T. Nakano and H. Kubo Japan Atomic Energy Agency

Acknowledge to J. Yanagibayashi at Kyoto Univ.

A. Sasaki at JAEA

Measurement of W44+ and W45+ density ratio in JT-60U

2P3/2

W45+ :3d104s

W46+ :3d10

2P1/2 (2.24 eV) 電離

励起

（電子衝突）

(イオン衝突）

自然放出

=

!

AFDnD + Fene + A + neS1/ 2

nDCD + neCe( )nAr9+ + neSenAr8+[ ]

!

"1/ 2#3 / 2

A=1

03 s

-1

F D

CD

F e

Ce

Se

S1/

2

FD CD Fe Ce

Se

S1/2

Colonal model is valid

10-19

10-18

10-17

10-16

10-15

10-14

Ra

te c

oeffic

ient (

m3 / s

)

103

104

Te ( eV )

Ionization: W45+

(4p) -> W46+

Excitation: W45+

(4p) -> n=4 or n=5

Tungsten as a plasma-facing component Merit : high melting point => compatible with high temp. plasma

: low hydrogen (T) retention => safety, economy : low sputtering yield => long lifetime

Demerit : high Z (74) => highly radiative( allowable nW/ne < 10-5) => accumulation in the core plasma*)

Highly charged W ions from a view point of atomic physics Atomic structure, CI, QED, ,,, Interface between atomic physics and fusion research spectral data ( wavelength, A coeff. ) W density collisional data (ioniz./recomb coeff.) ( W charge state distribution )

ITER

W

*) T. Nakano et al., Nucl. Fusion 49 (2009) 115024.

High temp. plasma of JT-60U ( > 10 keV ) can produce highly charged W ions ( > 60+). Studies of atomic physics are possible, contributing to plasma physics.

Introduction: Atomic Physics and Fusion Research

Significant difference in Ionization equilibrium

0.001

0.01

0.1

1F

ractio

na

l A

ba

nd

an

ce

0.001

0.01

0.1

1

Fra

ctio

na

l Ab

an

da

nce

103

104

Te ( eV ) Te ( eV ) Te ( eV )

103 104 103 104

FLYCHK code

LLNL code

T Putterich et al Plasma Phys. Control. Fusion 50 (2008) 085016

Experimental validation needed =>JT-60U plasmas

44+ 45+

46+

AUG exp

W spectra calculated by FAC

Constant excitation ratio of W45+ and W44+ for 4s-4p transition

!

IW 44+(4s" 4 p) = A(4s,4 p)• nW 44+(4 p) = C44+(4s,4 p)• nW 44+(4s)• ne

!

IW 45+(4s" 4 p) = A(4s,4 p)• nW 45+(4 p) = C45+(4s,4 p)• nW 45+(4s)• ne

!

~ 0.44 •nW 45+(4s)nW 44+(4s)

Coronal model:

~ 6.1 nm ~ 6.2 nm

10-11

10-10

10-9

10-8

Excitation r

ate

( c

m3 / s

)

101

102

103

104

105

Electron temperature ( eV )

1.5

1.0

0.5

0.0

Ra

tio o

f E

xcitation r

ate

s

W44+

: 4s2 1

S0 - 4s4p 1P1, 205 eV, 204 eV, 205 eV

W45+

: 4s 2

S1/2 - 4p 2P3/2, 201 eV, 199 eV, 200 eV

W44+

W45+

W45+

/ W44+

~ 0.44

LLNL, FAC, ORNL*

10-11

10-10

10-9

10-8

Excitation r

ate

( c

m3 / s

)

101

102

103

104

105

Electron temperature ( eV )

1.5

1.0

0.5

0.0

Ratio o

f E

xcitation r

ate

s

W44+

: 4s2 1

S0 - 4s4p 3P1, 90.2 eV

W45+

: 4s 2

S1/2 - 4p 2P1/2, 96 eV

W44+

W45+

W45+

/ W44+

~ 0.67

Constant excitation ratio of W45+ and W44+ for 4s-4p transition

!

IW 44+(4s" 4 p) = A(4s,4 p)• nW 44+(4 p) = C44+(4s,4 p)• nW 44+(4s)• ne

!

IW 45+(4s" 4 p) = A(4s,4 p)• nW 45+(4 p) = C45+(4s,4 p)• nW 45+(4s)• ne

!

~ 0.67•nW 45+(4s)nW 44+(4s)

Coronal model:

~ 13.3 nm ~ 12.7 nm

W divertor plates in JT-60U

W coated CFC tiles: 50 µm with Re multi-layer 12 tiles (1/21 toroidal length )

Dome Inner Div.

Outer Div.

Diagnostics Flat-field grazing incidence spectrometer •  Incident angle: 89° •  Wavelength range : 0.5 - 40 nm •  Wavelength resolution: 0.01 nm @ 5 nm •  Time resolution : 20 ms •  On-axis : for plasma core •  Off-axis : for plasma edge

TMS

CO2

FIR

Visib

le

VUV(on-axis)

VUV

(off-

axis)

16

7

1PIN

48

CXRS

1.80 2.80 3.80 4.80R (m)

-1.0

0.00

1.00

Z (m

)

W-tile

(a)Ferrite tiles

PIN　 Soft X-ray (>3keV) CXRS Toroidal rotation TMS Te, ne FIR, CO2 line density

Waveform of Reversed Shear discharge with EC injection

1.5

1.0

0.5

0.0

I p (

MA

)

15

10

5

0 PN

B, P

EC (

MW

)E048141

12

8

4SX

( c

h ) 0.3

0.2

0.1

0.0

(a.u

.)

10

5

Te (

eV

)

6

3

0 ne (

10

19 m

-3 )

5

0

I W

XLV

I ( a

.u. )

1210864

Time ( s )

1

0

I W I

( 1

017 p

h s

r-1 m

-2 s

-1 n

m-1

)

EC NB

Reversed shear discharge: W accumulation occurs even with 1. positive toroidal rotation 2. EC injection

Te decreases after t=8 s.

Waveform of W45+ intensity is NOT similar to that of SX.

During Te decrease, IW45+ increases, and then decreases => Te scan

VUV Spectrum

1

0

Inte

nsity (

a.u

.)

151413121110987654321

Wavelength (nm)

0.30.20.10.0

Fractional Abundance

52

51

50

49

48

47

46

45

44

43

42

Ti-like

Cr-like

Fe-like

Zn-like

q

W 4

7+

- 4

9+

W 4

8+

- 5

2+

W 4

5+

W 4

1+

- 4

4+

W 4

2+

- 4

3+

Te = 5 keV

! n =0

! n =0

of W q+

Observed

Synthesized

(n =4)

(n =3)

E048141 t=9.5-9.6s

O7+

C5+

( On-axis VUV )

Ni-like No !n =0 transitions

W 4

5+

W 4

4+,

Fe

19+

, 2

2+

W44+ at 6.1 nm blends with W42+,43+

W44+ at 13.3 nm blends with Fe19+,22+

1.5

1.0

0.5

0.0

I p ( M

A )

15

10

5

0 PN

B, P

EC (

MW

)E048141

Waveform

W45+/W44+ ratio increases with decreasing Te. Blend is obvious at 4-8 s. Not used for analysis

W45+/W44+ ratio decreases with decreasing Te. used for analysis

10

5T e (

eV ) 6

3

0 n e (

1019

m-3

)

5

0

I W45

+ , I W

44+

1

0

I W45

+ / I W

44+

W44+W45+

Ratio @ ~ 6 nm

1

0

I W45

+ , I W

44+

1210864Time ( s )

1

0

I W45

+ / I W

44+

W44+

W45+Ratio

@ ~ 13 nm

W44+ at 6.1 nm blends with W42+,43+

W44+ at 13.3 nm blends with Fe19+,22+

0.001

2

4

0.01

2

4

0.1

2

4

1

W4

4+, W

45

+ fra

ctio

nal A

bandance

103

2 3 4 5 6 7 8 9

104

Electron temperature ( eV )

0.1

1

10

100R

el d

ensity r

atio (

W45

+ / W

44

+ )

LLNL

FLYCHK

ASDEX-U

Measured W45+/W44+ closer to LLNL than FLYCHK and AUG results

At high temperature, blend of W44+ with W43+, 42+ should be low ⇒  high accuracy, better comparison At low temperature, the blend reduces the W45+/W44+ ratio ⇒ Te-dependence should be weaker

44+ 45+

45+ 44+

103

2 3 4 5 6 7 8 9

104

Electron temperature ( eV )

0.1

1

10

100R

el d

ensity r

atio (

W45

+ / W

44

+ )

LLNL

FLYCHK

ASDEX-U

Measured W45+/W44+ closer to LLNL than FLYCHK and AUG results

At high temperature, blend of W44+ with W43+, 42+ should be low ⇒  high accuracy, better comparison At low temperature, the blend reduces the W45+/W44+ ratio ⇒ Te-dependence should be weaker

70

60

50

40

Mean Ion C

harg

e

2015105

Te ( 103 eV )

ALICE ATOMIC AVERROES CORA_H7 CORD_H7 CRETIN FLYCHK JATOM SCRAMCA SCRAM_H SCSF

Results from the 6th NLTE code comparison workshop through the courtesy of A. Sasaki

NLTE workshop: code-code comparison under fix conditions ⇒  Difference between codes reduces every meeting But still big difference at 7 keV

1x1020 m-3

103

2 3 4 5 6 7 8 9

104

Electron temperature ( eV )

0.1

1

10

100R

el d

ensity r

atio (

W45

+ / W

44

+ )

LLNL

FLYCHK

ASDEX-U

No codes reproduce both the W45+/W44+ ratio and the Te-dependence

Measured W45+/W44+ ratio is 4 keV: in the lowest range of the NTLE code results 7 keV: below the NTLE code results

ALICE ATOMIC AVERROES CORA_H CORD_H CRETIN FLYCHK JATOM SCRAMCA SCRAM_H SCSF

Summary

Analysis of intensity ratio of W45+ to W44+ line • W45+/W44+ density ratio is directly determined with the W44+/W45+ line intensity ratio by coronal model.

Comparison of measured W45+/W44+ density ratio with calculated • LLNL code: close to the measured density ratio but in the Te range where fractional abundances of W45+,44+ are very low. • FLYCHK code: higher by one order of magnitude • AUG-EXP: higher by 3 – 4 factors • NLTE6 codes: don’t reproduce both the ratio and

Te-dependence. Further study is needed:

Theory: improvement of recombination rates Experiment: blend free (higher wavelength resolution), EBIT

Thank you!

W~60+(3s-3p,3p-3d) at 2 nm identified in JT-60U*)

0.8

0.4

0.0

Inte

nsity

(a.u

.)

98765432Wavelength (nm)

20100

656463626160595857565554

F-like W65+

Ne-like W64+

Na-like W63+

Mg-like W62+

Al-like W61+

Si-like W60+

P-like W59+

S-like W58+

Cl-like W57+

Ar-like W56+

K-like W55+

Ca-like W54+

E049786

q Synthesized

C5+O

7+

W55+~61+

(3p-3d) W60+~63+

(3s-3p)

W43+~45+

(4s-4p)

2pn

3sn

3pn

3dn

(a)

(b)

Assumed FractionalAbundance (%)

(c)3 keV

12 keV13 keV

Calculated by FAC 12 keV, 4x1019 m-3

JT-60U

Wavelength ( nm ) *) J. Yanagibayashi, T. Nakano et al., submitted to J. Phys. B **)Y. Ralchenko et al J. Phys. B 41 (2008) 021003

EBIT(NIST)** 3s-3p lines at 7-8 nm identified in EBIT** were reproduced by the FAC calculation. ⇒  3s-3p at 2.3 nm ⇒  3p-3d at 2 nm

1.5

1.0

0.5

0.0

I p ( M

A )

15

10

5

0 PN

B, P

EC (

MW

)E048141

Waveform

10

5T e (

eV ) 6

3

0 n e (

1019

m-3

)

5

0

I W45

+ , I W

44+

1

0

I W45

+ / I W

44+

W44+W45+

Ratio @ ~ 6 nm

10

5

0

I W45+, I W

45+

10864

Time ( s )

1.0

0.5

0.0

I W45

+/ I W

45+

W45+

@ 6.2 nm

W45+

@ 12.7 nmRatio

~0.161 0.67/0.16 = 4.2 12.7 nm では 6.2 nm の感度の1/4.2と概算される

10-11

10-10

10-9

10-8

Exc

itatio

n ra

te (

cm3 /

s )

101 102 103 104 105

Electron temperature ( eV )

1.5

1.0

0.5

0.0

Rat

io o

f Exc

itatio

n ra

tes

W45+: 4s 2S1/2 - 4p 2P1/2, 96 eVW45+: 4s 2S1/2 - 4p 2P3/2, 201 eV

W45+ / W44+ ~0.66