STUDY OF EUV SPECTRA FROM AL X- PINCH AND WIRE ARRAY IMPLOSIONS

PRODUCED ON THE 1 MA “ ZEBRA” AT UNR

P.G. Wilcox, A. S. Safronova, V. L. Kantsyrev, U. I.Safronova, K. Williamson

University of Nevada, Reno, NV USAK. Struve, B. Jones, C. Deeney*, P.D. LePell**

Sandia National Laboratories, Albuquerque, NM USA

HEDP Summer School 2007 , 29 July-4 Aug. , UCSD San Diego ,CA

ABSTRACT

It is well known that implosions of X-pinches and wire arrays produce powerful laboratory x-ray sources. X-ray spectroscopy is a very useful

tool for diagnostics of X- and Z-pinch plasmas at stagnation while EUV spectroscopy seems to be an appropriate tool of diagnosing the plasma before and after the stagnation. Though x-ray spectra that characterize the stagnating plasmas are intensively used for X- and Z-pinch plasma diagnostics the EUV spectra are not yet studied in detail.

In the present work a collection of EUV spectra from implosions of very different X- and Z-pinch loads on the 1MA Zebra generator at UNR is presented for the first time. Specifically, the loads were Al X - pinches, cylindrical wire arrays (with a small portion of NaF coating), and planar wire arrays ( see [1-2] for the details of the experiments).

Non-LTE kinetic model of Al that was recently used to model X-ray K-shell Al spectra from the planar wire arrays[3] was applied here to calibrate and identify the EUV spectra. Preliminary plasma parameters were computed. Similar and different features of the EUV spectra from the above-mentioned loads were identified and analyzed. Future work is discussed.

• The kinetics modeling of Al spectra depends on the plasma conditions (parameters Te , Ne).

• The atomic dataset was generated for the new Al model and used as an input to SCRAM ( non-LTE collisional –radiative kinetics code [4] )to model the Z-pinches spectra[3].

• It includes the ground states of all ions from neutral to bare nucleus.

• Energy level structures and complete radiative and collisional coupling data are calculated by the FAC atomic structure code [5].

• The levels are fully coupled by radiative decay and radiative recombination, collisional excitation and ionization, Auger decay and their reverse rates.

• All collisional rates are calculated by integrating collision cross sections over a Maxwellian electron distribution function.

Kinetics Modeling

Aluminum kinetics model

Collisional ionization, three-body recombination, & radiative recombination

Auger decay & dielectronic recombination

Radiative decay, collisional excitation & de-excitation

B-like

(15 lev.)

Be-like

(98 levels)

Li-like

(153levels)

He-like

(178 levels)

H-like

(36 levels)

Bare

Atomic data is generated using the FAC atomic structure package developed by M.F. Gu[5]

C-like

(41lev.)

N-like(70 lev.) O-like

(85 lev.)

Al -like

(4lev.)

Mg-like

(35lev.)

Na-like

(5 lev.)

F-like

(60lev.)Ne-like

(37lev.)

n = 2- 4n = 2- 3

n = 2- 6 n = 2- 7

n = 2- 3n = 2- 3

n = 2- 3n =2- 3

The X- and Z-pinch loads usedin experiments on 1 MA “Zebra”at UNR

• Al X-pinches with 2 and 4 wires from Al 5056 (95% Al and 5% Mg) and Al 1100 (99% Al) alloys

• Cylindrical wire arrays with NaF coating

• Planar wire arrays

X-Pinch and Planar Array

Shot # Load Material

432 X pinch,2w Al(1100)

468 X pinch,4w Al(5056)

785Cylindrical Array,8 w

Al(5056) + 5 %NaF

796Planar Array, 10w Al(5056)

787 Cyl.Arr.,8w Al(5056) + 5 %NaF

0 50 100 150 200 250 300

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty

Lambda

Al-IX , 200 ev , d20Al-VIAl-VIIAL-X

Modeling of EUV spectra from different Aluminum Ionization Stages

(Te = 200ev , Ne = 10²º cm-3)

0 50 100 150 200 250 300

0.0

0.2

0.4

0.6

0.8

1.0

I

Wavelength,A0

Al-V,200ev,d20Al-VIAl-VIII

0 10 20 30 40 50 60 70 80

0.0

0.2

0.4

0.6

0.8

1.0

I

Wavelength,A0

Al,X,0-70A,200ev,20

0 10 20 30 40 50 60 70 80

0.0

0.2

0.4

0.6

0.8

1.0

Wavelength,A0

I,au

Al-XI ,200ev,0-70A,d20

0 10 20 30 40 50 60 70 80

0.0

0.2

0.4

0.6

0.8

1.0

I,a

u

Wavelength,A0

Al-IX,200ev,d20,0-70A

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty,a

u

Wavelength,A0

Al,VI,50ev,d20,0-100AAl,VII,50ev,d20,0-100AAl,VIII,50ev,d20,0-100A

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty,a

u

lenght,Ao

Al,IX,50ev,d20,0-100AAl,X, 50ev,d20,0-100AAl,XI,50ev,d20,0-100A

Modeling of EUV spectra from Aluminum VI-XI (Te = 50ev ,100ev ; Ne=10²º cm-3)

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty,a

u

Wavelength,A0

Al,VI,100ev,d20 ,0-100AAl,VII,100ev,d20 ,0-100AAl,VIII,100ev,d20 ,0-100A

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty,a

u

Wavelength,A0

Al,IX,100ev,d20 ,0-100AAl,X,100ev,d20 ,0-100AAl,XI,100ev,d20 ,0-100A

0 50 100 150 200 250 300

0.0

0.2

0.4

0.6

0.8

1.0

I

Wavelength,A0

Al,VI,150ev,d20.0-300Al,VII,150ev,d20.0-300Al,VIII,150ev,d20.0-300

0 50 100 150 200 250 300

0.0

0.2

0.4

0.6

0.8

1.0

I

Wavelength,A0

Al,IX,150ev,d20.0-300Al,X,150ev,d20.0-300Al,XI,150ev,d20.0-300

Modeling of Ionization Stages in Aluminum (Te = 150ev ,200ev ; Ne = 10²º cm-3 )

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty,a

u

Wavelength,A0

Al,VI,200ev,d20,0-100AAl,VII,200ev,d20,0-100AAl,VIII,200ev,d20,0-100A

0 20 40 60 80 100

0.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty,a

u

Wavelength,A0

Al,IX,200ev,d20,0-100AAl,X,200ev,d20,0-100AAl,XI,200ev,d20,0-100A

References for the Indentification

6. R. Kelly,Atomic and Ionic Spectrum Lines below 2000 Å ,Vol. 16 (1987)

7. NIST -- http://physics.nist.gov/asd3.

8. Non-LTE Al modeling

9. A.Shevelko,L.Shmaenok et al, Physica Scripta,vol. 57, pp 276 – 282 (1998).

10. S.Hoory,U.Feldman at al,Journal of the Optical Society of America, vol.60, #11 (1970)

11. R. Stuik , PhD Thesis , Tech. University, Eindhoven, The Netherlands

Al EUV spectrum from “Sparky” *

0 50 100 150 200 250 300

0

20

40

60

80

100

120

140

160

180

200

In

te

nsity,a

u

Wavelength,A0

Sparky

39.6 AAl X

104 AAl VI

* For details about UNR table-top Z-pinch & laser plasma facility see [12]

0 50 100 150 200 250 300

0

20

40

60

80

100

120

140

160

180

200

In

ten

sity,au

Wavelength,A0

Sparky

39.6 A

Al X

78 AAl VIII

107AAl VI

88 AAl VI 104 A

Al VI

126 A Al V

Al EUV (“ Sparky”) line identification

___________________________________________________________

Al IX, X I I I I

_____________________________________________________

Al VIII II I

______________________________________________________

Al V , VI I I I I I

0 50 100 150 200 250 300

0

20

40

60

80

100

120

140

160

180

200

In

ten

sity,au

Wavelength,A0

Sparky

Al EUV (“ Sparky”) line identification

List of the Identified Lines

AL X Ref. 2s2p – 2p4p 6,7,8,9,10

2s2p – 2s3d 6,7,8,9,10

AL IX

2s2p² - 2s2p3d 6,7,8,9

AL VI Ref.

2s²2p4 - 2s²2p³3d 6,7,8,9,11 2s²2p4 - 2s²2p³3s 6,7,8,9,11

Al V

2s²2p5 - 2s²2p4(¹D)3s 6,7,11

2s²2p5 - 2s²2p4(3P)3s 6,7,11 AL VIII

2s²2p² –2s² 2p3d 6,7,8,9 2s2p³ – 2s2p²3s 6,7,8,9

Comparison and

Identification

of the Al EUV “Zebra” Shots

Sparky

Zebra

796

_Wavelength, A_ 50 ________100_A_____150________200_________>

Al V,VI ,VIII I I I I II II

(Pl.Ar.,10w)

Zebra 787

Sparky

_Wavelength, A____50_________100_A__________150 ________________>

Al V,VI ,VIII I I I I II II

(Cyl.Arr.,8w)

Zebra

432

Zebra

796

_Wavelength, A___ __50_______100_A______150 ____________>

Al V,VI ,VIII I I I I I I II

(Pl.Ar.,10w)

(X,2w)

Zebra

796

Zebra

785

_Wavelength, A________50________100_A______150_______>

Al V,VI ,VIII I I I I II II

(Pl.Ar.,10w)

(Cyl.Arr.,8w)

Zebra

796

Zebra

787

Wavelength, A_50_______100_A______150____________>

Al V,VI ,VIII I I I I I I II

(Pl.Ar.,10w)

(Cyl.Arr.,8w)

Conclusions

Non - LTE kinetic model of Al is used to model EUV Al spectra.

Preliminary plasma parameters (Te =200ev, Ne=10²º cm-3) are computed.

The different spectral features of EUV spectra from the Aluminum loads in experiments on “Zebra” are identified and analyzed .

Predominantly low ionization stages that we found in “Zebra” shots indicate relatively lower Te than on “Sparky”.

Higher ionization stages lines are widely broadened due to the increased number of collisions in denser “Zebra” plasma ( in

comparison with “Sparky”).

Future Work

• 1.Modification of the model to include high Rydberg

states for Li~, B~, and C~ Aluminum.

• 2.Modeling of EUV spectra from “Zebra” and analysis of

plasma parameters with connection to the type of load.

• 3. Analysis of EUV spectra from wire Z- and X- pinch

loads.

References and Acknowledgments 1. V.L. Kantsyrev, A. S. Safronova et al, IEEE transactions on plasma science , vol. 34, No.2 (Apr. 2006). 2. B. Jones, C. Deeny, V.Kantsyrev et al, ICOPS 2006, CP808. 3. A.S.Safronova, V.L. Kantsyrev et al , HEDP 3(2007) pp.237-2415 4. S.B. Hansen. PhD Dissertation, University of Nevada,Reno (2003). 5. M.F. Gu. , AIP conference proceedings; 730: 127 (2004). 6. R. Kelly,Atomic and Ionic Spectrum Lines below 2000 Å ,Vol. 16 (1987) 7. NIST -- http://physics.nist.gov/asd3. 8. Non-LTE Al modeling 9. A.Shevelko,L.Shmaenok et al, Physica Scripta,vol. 57, pp 276 – 282 (1998). 10.S.Hoory,U.Feldman at al,Journal of the Optical Society of America, vol.60, #11 (1970) 11. R. Stuik , PhD Thesis , Tech. University, Eindhoven, The Netherlands 12. V.L. Kantsyrev, D. A. Fedin et al,Proc. of SPIE, vol. 59180W, pp. 1-7 ( 2005).

* This work was supported by NNSA under DOE Cooperative Agreements DE-FC52-06NA27588, DE-FC52- 06NA27586,and DE-FC52-06NA27616.Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04- 94AL85000 .