Illumination Uniformity Studyfor the Direct Drive

J.-L. Feugeas Centre Lasers Intenses et Applications,Université Bordeaux 1 – CNRS – CEAFrance

6th Direct Drive and Fast Ignition Workshop

Lisbon, 11th–14th May

J.-L. Feugeas CELIA 2

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

Collaborators

J.-L. Feugeas CELIA 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 4

Summary/Conclusions

Speckle pattern for each beam

CECLAD

A tool to study the illumination : various 3D configurations

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

A tool to study the illumination : absorption

A tool to study the illumination : robustness analysis

Normal variation of target or beam imperfections :

Beams size variationTarget position

Beams balance Beams pointing Beams centering

1/e

2

expm

xx

a

a

m=1m=2m=3m=4

a

m

A tool to study illumination : diagnostic of optimisation

A tool to study the illumination : Legendre analysis

11

x100 x100

8

12

10

rms = 0.15 %a = 0.61m = 1.0248 (-4)

A tool to study the illumination : validation

Validation with studies of the literature : Ref. POP B. Canaud et al 2002

rms = 16.23 % rms = 0.2474 %

49°59°5

33°2

59°578°

33°2

Validation with analytical solutions (Ref. J. Opt J. Xiao and B. Lu) : - perfect uniform irradiation

Validation with known configuration : Omega

HIPER

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

70 kJ10 ps PW

300 kJ50 beams

5 ns, 2-3

J.-L. Feugeas CELIA 15

rms (%)(%)

0.09

0.06

0.15

0.12

0.18

0.31

0.96

1.73

94

97

94

96

97

87

79

78

0.631.0860 ()

0.5671.06760 (-5)

0.611.0248 (-4)

0.631.1246 (-8)

0.791.942 (-5)

0.831.3332 (-1)

1.011.668 (-1)

1.021.636 (-1)

amNb

The 48 beams configuration is a good candidate : 0.12 % RMS

a

m

target

beams

E

E

J.-L. Feugeas CELIA 16

The 48 beams configuration seems the best candidate with the cone

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

47°74°95

21°24

47°74°95

30°

Calotte : r2 = (R sin(30°))2

r2/ 4R2 = 1/16 = 6.25 %

Beams off4/48 = 1/12 = 8.33 %

5/42 = 11.9 %8/46 = 17.4 %5/60 = 1/12 = 8.33 %

rms (%)(%)

0.1294 %0.611.0248 (-4)

amNbtarget

beams

E

E

J.-L. Feugeas CELIA 17

The 48 beams configuration is a good candidate

J.-L. Feugeas CELIA 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

x100 x100

8

12

10

rms = 0.15 %a = 0.61m = 1.0248 (-4)

The 48 beams configuration : Legendre analysis

20

rms = 0.15 %a = 0.61m = 1.0244

J.-L. Feugeas CELIA 21

At the end of the

11 ns11 ns 10.4 ns

10.6 ns10.8 ns

1-50 modesEnd of free flight timeWeakly non linearMode 12 dominates

J.-L. Feugeas CELIA 22

Robustness of the 48 beams configurationNormal 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.

1.05 %0.26 %0.59 %rms (0.15 %)

maxminmean after 100.000 configurations

Normal repartition of the beam to beam imbalance A Gaussian repartition around 10 % of balance imperfections between beams after 100 000 configurations

Robustness of the 48 beams configuration

J.-L. Feugeas CELIA 25

1.05 %0.26 %0.59 %rms (0.15 %)

maxminmean after 100.000 configurations

Normal repartition of the beam to beam imbalance A Gaussian repartition around 10 % of balance imperfections between beams after 100 000 configurations

3.2 %0.82 %1.2 %rms (0.15 %)

maxminmean after 100.000 configurations

Normal repartition of the beam pointing A Gaussian repartition around 5 % of beam defaults of pointing after 100 000 configurations

%%%rms (0.15 %)

maxminmean after 100.000 configurations

Normal repartition of the beam centering A Gaussian repartition around 2 % of beam centering after 100 000 configurations

Robustness of the 48 beams configuration

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

J.-L. Feugeas CELIA27

IRRADIATIONIllumination non uniformity48 beams, (a=0.61, m=1.02.)

rms = 0.15 %,

l-modes : 12, 8 and 10Energy : 130 kJ

LOW MODESASYMETRY

Hydrodynamics instabilities analysis

TARGETBaseline target definition

Small - Large - Reference

FACILITY

X Ribeyre, Ph Nicolaï, G Schurtz, M Olazabal-Loumé, J Breil, P.-H. Maire, J.-L. Feugeas, L Hallo and V. T Tikhonchuk

Algorithm of definition of nominal configuration

LMJ

Optimisation de configuration d’éclairement

Attaque Directe en configuration LMJ attaque indirecte (33°2, 49°, 59°5)

Sens trigonométriqueΘ1 Θ2 Θ3

a : tachem : puissance

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

décentrage

Θ

DECENTRAGE

Retrouver les résultats existant

J.-L. Feugeas CELIA 31

Configuration :LMJ able to produce1.8 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

49°59°5 49°

59°5

49°59°5

33°259°5

78°

33°2

49°59°5

33°2

J.-L. Feugeas CELIA 32

49°59°5

33°2

J.-L. Feugeas CELIA 33

59°578°

33°2

x100

J.-L. Feugeas CELIA 34

49°59°5

33°2

J.-L. Feugeas CELIA 35

49°59°5

33°2

x100

J.-L. Feugeas CELIA 36

49°59°5

x10

J.-L. Feugeas CELIA 37

49°59°5

x100

J.-L. Feugeas CELIA 38

Configuration :LMJ able to produce1.8 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

49°59°5

33°2

49°59°5

Solution optimale calculé par le code d’éclairement

srms = 0.16 %Pi / Pa = 133/167 = 79,44%

srms = 16.23 %Pi / Pa = 137/160 = 85,7%

Θ1 = 11.88 °Θ2 = 5.33 °Θ3 = 19,22 °

a = 1m = 1.91

Attaque Directe en configuration LMJ attaque indirecte (33°2, 49°, 59°5)

Optimisationde configuration

The 48 beams configuration is a good candidate