FOM-Institute for Plasma Physics RijnhuizenAssociation Euratom-FOM

T E C

T E C

Carbon Chemical Erosion Yield Experiments in Pilot-PSI

Jeroen WesterhoutThe Pilot-PSI and Magnum-PSI team:

W.A.J. Vijvers, R.S. Al, H.J.N. van Eck, B. de Groot, W.R. Koppers, H.J. van der Meiden, R.J.E. van de Peppel, M.J. van de Pol, P.R. Prins, W.F. van Prooijen, A.E. Shumack, L.W. Veldhuizen, A.W. Kleyn, W.J. Goedheer, N.J. Lopes Cardozo and G.J. van Rooij

: R. Engeln, D.C. Schram

Forschungszentrum Jülich (TEC): S. Brezinsek

Chemical Erosion and Transport Meeting - 23-03-2007 2

T E CContents

• Pilot-PSI

• Results– Plasma Conditions– Power to Target– Spectroscopy– Profilometry

• Discussion

• Conclusions

• Magnum-PSI

Chemical Erosion and Transport Meeting - 23-03-2007 3

T E CExperimental Setup: Pilot-PSI

Source TargetB

Coils

Water cooling

To pumps

Chemical Erosion and Transport Meeting - 23-03-2007 4

T E CExperimental Setup: Diagnostics

Spectrometer

Target

Calorimetry from cooling water

Thomson Scattering at 17 mm in front of target

Window

Chemical Erosion and Transport Meeting - 23-03-2007 5

T E CResults: Plasma Conditions

5

4

3

2

1

0Ele

ctro

n te

mpe

ratu

re (

eV)

Electron density (m-3)1019 1020 1021 1022

6 Target floatingTarget grounded

0.4 T0.8 T1.2 T1.6 T

≥ 200 A150 A100 A

Chemical Erosion and Transport Meeting - 23-03-2007 6

T E C

-8 -4 0 4 80

4

8

12

16

20

Hea

t flu

x (M

W m

-2)

Position (mm)

Results: Power to Target

• ne = 1.2 ± 0.1·1021 m-3, Te = 2.0 ± 0.2 eV, assume v = 3000 m/s, assume E = Eion + Ediss + 3/2 k(Te + Ti))→ Peak heat flux = 12.6 MW m-2

• Integrated profile→ Flux = 3.7·1020 s-1 → Power = 1.2 kW

• Power in cooling water 1.8 kW

→ Plasma velocity? Target temperature?

Chemical Erosion and Transport Meeting - 23-03-2007 7

T E CResults: Spectroscopy

• S/XB from ADAS, D/XB from HYDKIN

422 426 430 4340

2

4

6

8

Inte

nsity

(a.

u.)

Wavelength (nm)

CH

H-

0.4 nm

Chemical Erosion and Transport Meeting - 23-03-2007 8

T E CResults: Spectroscopy

• Ion flux: = ne·v, assume v = 3000 m/s

0 1 2 3 40

4

8

12

16

Bal

mer

- fl

ux (

a.u.

)

Ion flux (×1024 m-2 s-1)

Chemical Erosion and Transport Meeting - 23-03-2007 9

T E CResults: Profilometry

• 1.0 slm H2, 100 A, 0.4 T, target grounded, 100 sec.

• ne = 0.9 ± 0.1·1020 m-3, Te = 4.0 ± 0.2 eV

→ Peak heat flux = 1.2 MW m-2

10 mm-8 -4 0 4 80.0

0.2

0.4

0.6

0.8

1.0

Ele

ctro

n de

nsity

(×

1020

m-3)

Position (mm)

Chemical Erosion and Transport Meeting - 23-03-2007 10

T E C

Position (mm)

Results: Profilometry

10 mm

30

0

-30

Hei

ght (

µm

)

5 10 15 20

-8 -4 0 4 80.0

0.2

0.4

0.6

0.8

1.0

Ele

ctro

n de

nsity

(×

1020

m-3)

Position (mm)

Chemical Erosion and Transport Meeting - 23-03-2007 11

T E CResults: Profilometry

• B10: 2 slm H2, 120 A, 0.4-1.2 T, varying current to the target (up to 120 A).

• ne = 9.5 ± 0.5·1020 m-3, Te = 2.9 ± 0.1 eV

→ Peak heat flux = 11.2 MW m-2

10 mm-15 -10 -5 0 5 100

4

8

12

Ele

ctro

n de

nsity

(×

1020

m-3)

Position (mm)

Chemical Erosion and Transport Meeting - 23-03-2007 12

T E CResults: Profilometry

10 mm

20

0

-20 -40

Hei

ght (

µm

)

5 10 15 20Position (mm)

-15 -10 -5 0 5 100

4

8

12

Ele

ctro

n de

nsity

(×

1020

m-3)

Position (mm)

Chemical Erosion and Transport Meeting - 23-03-2007 13

T E CResults: Profilometry

• Erosion ≈ 0.94 mm3

• Deposition ≈ 0.47 mm3

20

0

-20

-40

Hei

ght (

µm

)

5 10 15 20Position (mm)

50 %

> 150 μm

Chemical Erosion and Transport Meeting - 23-03-2007 14

T E CResults: Chemical Erosion

Pilot-PSI

J. Roth et al., Journal of Nuclear Materials, Vol. 337-339, Iss. 1 (2005), 970-974

Chemical Erosion and Transport Meeting - 23-03-2007 15

T E CDiscussion

• Plasma velocity → Flux

• Target temperature (time dependence)

• Erosion profiles (anode spots)

• Rings (colours)

• Composition of deposited material

Chemical Erosion and Transport Meeting - 23-03-2007 16

T E CConclusions

• ITER-like conditions achieved in Pilot-PSI

• First chemical erosion results are in line with literature

• Erosion process(es) not fully understood

Chemical Erosion and Transport Meeting - 23-03-2007 17

T E CMagnum-PSI

Superconducting magnet

Chemical Erosion and Transport Meeting - 23-03-2007 18

T E CMagnum-PSI

Access ITER relevant regime of PSI:• 1024 ions m-2 s-1 in H2 or D2

• 3 T magnetic field• 10 cm beam diameter• Low plasma temperature < 7 eV• 5-10 MW m-2 energy flux density on target• Pressure near target 1-10 Pa

Total length: 14 m

Chemical Erosion and Transport Meeting - 23-03-2007 19

T E CFuture Work

• Plasma velocities (and neutrals)

• Target temperature → improve cooling

• Spectroscopy with fiber bundle (chemical erosion profile)

• Magnum-PSI source development: widening the plasma beam

FOM-Institute for Plasma Physics RijnhuizenAssociation Euratom-FOM

T E C

T E C

Carbon Chemical Erosion Yield Experiments in Pilot-PSI

Jeroen WesterhoutThe Pilot-PSI team:

W.A.J. Vijvers, R.S. Al, B. de Groot, H.J. van der Meiden, R.J.E. van de Peppel, M.J. van de Pol, P.R. Prins, W.F. van Prooijen, A.E. Shumack, L.W. Veldhuizen, A.W. Kleyn, W.J. Goedheer, N.J. Lopes Cardozo and G.J. van Rooij

: R. Engeln, D.C. Schram

Forschungszentrum Jülich (TEC): S. Brezinsek

Chemical Erosion and Transport Meeting - 23-03-2007 21

T E CResults: Plasma Conditions

5

4

3

2

1

0Ele

ctro

n T

empe

ratu

re (

eV)

Electron Density (m-3)1019 1020 1021 1022

6 Target floatingTarget grounded

0.4 T0.8 T1.2 T1.6 T

≥ 200 A150 A100 A

A9

Chemical Erosion and Transport Meeting - 23-03-2007 22

T E CResults: Power to Target

• ne = 0.95 ± 0.05·1020 m-3, Te = 4.0 ± 0.3 eV, 100 sec. → Peak heat flux = 1.2 MW m-2

• Integrated profile→ Flux = 3.3·1019 s-1 → Power = 100 W

• Power in cooling water 940 W

→ ?

Chemical Erosion and Transport Meeting - 23-03-2007 23

T E CResults: Power to Target

• 55 A

• ne = 8.5 ± 0.5·1020 m-3, Te = 2.3 ± 0.1 eV

• Flux = 2.8·1020 s-1

• W = 1.4 kW

• 120 A

• ne = 10 ± 0.5·1020 m-3, Te = 2.9 ± 0.1 eV

• Flux = 3.4·1020 s-1

• W = 2.6 kW

• 1.8 slm H2, 200 A, 0.8 T, current to target: