1. Illumination Uniformity Study
for the Direct Drive
J.-L. Feugeas
Centre Lasers Intenses et Applications,
Université Bordeaux 1 – CNRS – CEA
France
6th Direct Drive and
Fast Ignition Workshop
Lisbon, 11th–14th May

2. Collaborators J. Breil, Ph. Nicolaï, G. Schurtz
L. Hallo, M. Olazabal-Loumé, X. Ribeyre
Centre Lasers Intenses et Applications,
Université Bordeaux 1 - CNRS- CEA,
33405 Talence cedex, France
J.-L. Feugeas CELIA 2

3. Summary
A new tool has been developed to provide a nominal configuration of illumination for any direct drive project
The code CECLAD has been developed in CELIA to study the direct-drive illumination of any target
Several parameters have been studied to optimize the uniformity of illumination
- Beam size variation
- Beam balance
- Beam pointing
- Beam centering
- Target position
A solution of illumination has been proposed to answer to the baseline specification of HIPER
J.-L. Feugeas CELIA 3

4. Summary/Conclusions Speckle pattern for each beam 4
J.-L. Feugeas CELIA 4

5. CECLAD

6. A tool to study the illumination : various 3D configurations

7. A tool to study the illumination : control parameters of each beams

8. A tool to study the illumination : absorption

9. A tool to study the illumination : robustness analysis
Normal variation of target or beam imperfections :
Target position
Beams size variation
Beams balance
Beams pointing
Beams centering

10. A tool to study illumination : diagnostic of optimisation
1/e a
m=1
m=2
m=3
m=4

11. x100 x100 A tool to study the illumination : Legendre analysis 12 10 8
rms = 0.15 %
a = 0.61
m = 1.02
48 (-4) 12
x100
x100 10 8 11

12. A tool to study the illumination : validation
Validation with studies of the literature : Ref. POP B. Canaud et al 2002
49°
59°5
33°2
78°
59°5
33°2
rms = %
rms = %
Validation with analytical solutions (Ref. J. Opt J. Xiao and B. Lu) :
- perfect uniform irradiation
Validation with known configuration : Omega

13. HIPER

14. 300 kJ on target – 15 kJ per beams – 50 beams @ 3
The specification for HiPER : number of compression (ns) beams
Modelling with a shaped adiabat (Atzeni, Bellei, Schiavi)
based on theoretical and experimental work by Betti et al (LLE)
Energy :
300 kJ
15 kJ per beam at the output of the main amplifier section
Wavelength :
2 baseline : conversion 70 %
3 option : conversion (70 %)2 = 50 %
Transmission : 80 %
A 3 : 50 beams x 15 kJ x 50 % (conversion 3) x 80 % (transmission) = 300 kJ
Pulse shape : Adiabatic shock plus ramp plus final < 200 ps resolution
300 kJ
50 beams
5 ns, 2-3
70 kJ
10 ps PW

15. a m The 48 beams configuration is a good candidate : 0.12 % RMS Nb m a
(%)
rms (%)
6 (-1)
1.63
1.02 78
1.73
8 (-1)
1.66
1.01 79
0.96
32 (-1)
1.33
0.83 87
0.31
42 (-5)
1.9
0.79 97
0.18
46 (-8)
1.12
0.63 96
0.12
48 (-4)
1.02
0.61 94
0.15
60 (-5)
1.067
0.567 97
0.06
60 ()
1.08
0.63 94
0.09 a m
J.-L. Feugeas CELIA 15

16. The 48 beams configuration seems the best candidate with the cone
rms (%)
(%)
0.12
94 %
0.61
1.02
48 (-4) a m Nb
47°
74°95
21°24
30°
The 48 beams configuration gives :
rms 0.15 %
ratio of power 94 %
disconnection of 1 (or 2) ring of 4 beams is enough to put the cone or beams dedicated for the fast ignition.
Robustness of the configuration :
zooming in time
stability analysis
Calotte :
r2 = (R sin(30°))2
r2/ 4R2 = 1/16 = 6.25 %
Beams off
4/48 = 1/12 = 8.33 %
5/42 = 11.9 %
8/46 = 17.4 %
5/60 = 1/12 = 8.33 %
J.-L. Feugeas CELIA 16

17. The 48 beams configuration is a good candidate
J.-L. Feugeas CELIA 17

18. The 48 beams configuration is a good candidate
The 48 beams configuration gives :
energy on the cone
energy in the cone reduced (0.08/4.18)
Other configurations lead to higher energy on/in the cone
J.-L. Feugeas CELIA 18

19. x100 x100 The 48 beams configuration : Legendre analysis 12 10 8
rms = 0.15 %
a = 0.61
m = 1.02
48 (-4)
x100
x100 19

20. rms = 0.15 %
a = 0.61
m = 1.02 44 20

21. At the end of the 1-50 modes End of free flight time Weakly non linear
Mode 12 dominates
11 ns
10.4 ns
11 ns
10.8 ns
J.-L. Feugeas CELIA
10.6 ns 21

22. J.-L. Feugeas CELIA 22

23. Robustness of the 48 beams configuration
Normal variation of
Beam imperfections :
Balance : 10 %
Beam pointing : 5 %
Beam centering : 2 %
Several low l-mode sources of direct-drive illumination non-uniformity can come from imperfections or can be significantly reduced by those same parameters.
Normal repartition of the beam to beam imbalance
A Gaussian repartition around 10 % of balance imperfections between beams after configurations
1.05 %
0.26 %
0.59 %
rms (0.15 %)
max
min
mean
after configurations
Marshall APS 03

24. Robustness of the 48 beams configuration

25. Robustness of the 48 beams configuration
Normal repartition of the beam to beam imbalance
A Gaussian repartition around 10 % of balance imperfections between beams after configurations
1.05 %
0.26 %
0.59 %
rms (0.15 %)
max
min
mean
after configurations
Normal repartition of the beam pointing
A Gaussian repartition around 5 % of beam defaults of pointing after configurations
3.2 %
0.82 %
1.2 %
rms (0.15 %)
max
min
mean
after configurations
Normal repartition of the beam centering
A Gaussian repartition around 2 % of beam centering after configurations %
rms (0.15 %)
max
min
mean
after configurations
J.-L. Feugeas CELIA 25

26. Robustness of the 48 beams configuration
Normal variation of
Beam imperfections :
Beam size variation : (a +/- a ,m +/- m )
Balance : 10 %
Beam pointing : 5 %
Beam centering : 2 %
Target position
Several low l-mode sources of direct-drive illumination non-uniformity can come from imperfections or can be significantly reduced by those same parameters.
For example, on OMEGA
Marshall APS 03

27. Algorithm of definition of nominal configuration
IRRADIATION
Illumination non uniformity
48 beams, (a=0.61, m=1.02.)
rms = 0.15 %,
l-modes : 12, 8 and 10
Energy : 130 kJ
TARGET
Baseline target definition
Small - Large - Reference
LOW MODES
ASYMETRY
Hydrodynamics
instabilities analysis
FACILITY 27
J.-L. Feugeas CELIA
X Ribeyre, Ph Nicolaï, G Schurtz, M Olazabal-Loumé, J Breil, P.-H. Maire,
J.-L. Feugeas, L Hallo and V. T Tikhonchuk

28. LMJ

29. Optimisation de configuration d’éclairement
Attaque Directe en configuration LMJ
attaque indirecte (33°2, 49°, 59°5)
DECENTRAGE
décentrage Θ
Avantages :
simplicité de mise en place et de réglages
Interrogation :
absorption
évolution en temps au cours de l’implosion
perte d’énergie (à coté)
robustesse
Sens trigonométrique Θ1 Θ2 Θ3
a : tache
m : puissance

30. Retrouver les résultats existant

31. of UV light for each beam. Goal : choc ignition
Configuration :
LMJ able to produce
1.8 MJ of UV light (3)
and 550 TW of peak power.
240 beams delivering 8.2 kJ
of UV light for each beam.
Goal : choc ignition
49°
59°5
33°2
49°
59°5
33°2
59°5
78°
33°2
49°
59°5
33°2
49°
59°5
49°
59°5
49°
59°5
33°2
J.-L. Feugeas CELIA 31

32. 49°
59°5
33°2
J.-L. Feugeas CELIA 32

33. 59°5
78°
33°2
x100
J.-L. Feugeas CELIA 33

34. 49°
59°5
33°2
J.-L. Feugeas CELIA 34

35. 49°
59°5
33°2
x100
J.-L. Feugeas CELIA 35

36. 49°
59°5
x10
J.-L. Feugeas CELIA 36

37. 49°
59°5
x100
J.-L. Feugeas CELIA 37

38. of UV light for each beam. Goal : choc ignition
Configuration :
LMJ able to produce
1.8 MJ of UV light (3)
and 550 TW of peak power.
240 beams delivering 8.2 kJ
of UV light for each beam.
Goal : choc ignition
59°5
49°
59°5
49°
49°
59°5
33°2
49°
59°5
33°2
J.-L. Feugeas CELIA 38

39. Optimisation de configuration
Solution optimale calculé par le code d’éclairement
Attaque Directe en configuration LMJ
attaque indirecte (33°2, 49°, 59°5)
Θ1 = °
Θ2 = 5.33 °
Θ3 = 19,22 °
a = 1
m = 1.91
srms = %
Pi / Pa = 137/160 = 85,7%
srms = 0.16 %
Pi / Pa = 133/167 = 79,44%
Optimisation
de configuration

40. The 48 beams configuration is a good candidate