1cea-dam ile-de-france high-gain direct-drive shock ignition for the laser megajoule:prospects and...
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1CEA-DAM Ile-de-France
High-Gain Direct-Drive Shock Ignition for the Laser Megajoule:prospects and first results.
B. CanaudCEA, DAM, DIFFrance
7th WorkshopDirect Drive
and Fast IgnitionMay, 3-6, 2009
Prague,
FCI2Direct Drive @ 2 rings
Density at stagnation
50 100Radius (µm)
50
100
2CEA-DAM Ile-de-France
Collaborators
X. Ribeyre, M. Lafon, J.L. Feugeas, J. Breil, G. SchurtzCELIA, Bordeaux
M. Temporal, R. Ramis ETSIA, Madrid, Spain
3CEA-DAM Ile-de-France
Standard LMJ direct drive illumination differs from indirect one by a more isotropic beam layout on the target chamber.
a) Baseline LMJ Direct Drive b) LMJ Indirect Drive
33.2° (10 beams)
49° (10 beams)
59.5° (10 beams)
Z
DT
33.2° (10 beams)
78° (10 beams)
59.5° (10 beams)
Z
DT
ID
DD
33.2°
59.5 °49°
78°
102°
131°120.5°
146.8°
Quad
Each LMJ beamlet is limited by its power max: Pmax ≤ 2.5 TW.
4CEA-DAM Ile-de-France
A few years ago, we proposed a new direct drive configuration with indirect drive beam layout [*]…
b) LMJ Indirect Drivea) Baseline LMJ Direct Drive
33.2° (10 beams)
78° (10 beams)
59.5° (10 beams)DT
33.2° (10 beams)
49° (10 beams)
59.5° (10 beams)
Z
DT
… but with only 1.2 MJ of laser energy.
(*) Canaud B. et al, Plasmas Phys. Cont. Fusion, 49, B601 (2007).
5CEA-DAM Ile-de-France
49° (45%)59.5° (55%)
Zearly time
late time
large spot
narrowspot
Focal spot zooming increases laser-target coupling efficiency[**].
1 beam large, 3 narrows on each quad.
With zooming and 2 rings,Gain=32 with 1 MJ laser.
With zooming and 2 rings,Gain=32 with 1 MJ laser.
A new 2-rings baseline(*) high-gain Direct-Drive design has been proposed with focal spot zooming.
(*) Canaud B. et al, Nucl. Fus., 47, 1642 (2007)
1 µm CH
DTgas
DT iceWetted foam
165 µm134 µm
1341 µm
Adiabat = 3.5 V=4.105 m/s
FCI2Direct Drive @ 2 rings
Density at stagnation
50 100Radius (µm)
50
100
(**) Canaud B. et al, Nucl. Fus., 45, L43 (2005)
6CEA-DAM Ile-de-France
Laser energy (MJ)with 3D ray-tracing
The
rmon
ucle
ar g
ain
Adiabat = 3.5 V=4.105 m/s
1 µm CH1642 µmDT gasDT iceCH(DT)n203 µm164 µm
0.1
1
10
100
0.4 10.6 3
w/o Zoomingw/ Zooming
LMJ design with zooming
Without zooming, the target is marginally igniting.
LMJ design without zooming
: adiabatv : implosion velocity
E, M f 3
R,t f
P f 2
Homothetic target family curve
7CEA-DAM Ile-de-France
• Isobaric ignition concerns standard direct drive ignition.
Alternative exists to displace the energy threshold towards lower energies, keeping constant the implosion target parameters (,v).
Hot-spot DTfuel
radius
T
PisoIsobaric Ignition threshold
Ethresholdisobaric
3
v 7
: adiabatic parameterv : implosion velocity
10-1
100
101
102
0,01 0,1
ET
h(MJ)
Ec (MJ)
Burn of
Hot spot
Burn of
DT fuel
E,M f 3
R,t f
P f 2
(*) Betti R. et al, Phys.Rev. Lett., 98, 155001 (2007)
• Non-isobaric ignition reduces the energy threshold for ignition.
E thresholdnon isobaric
E thresholdisobaric
Hotspot
DTfuel
radius
T
Pnon iso
where
P non isobaric
P isobaric
3
Piso
8CEA-DAM Ile-de-France
• A low-isentrope compression is obtained by a usual pulse shape.
Non isobaric conditions can be achieved by launching a strong shock at the end of the implosion.
• An additional spike launches a strong shock in the target.
tspike
Pspike
9CEA-DAM Ile-de-France
Shock can be created by the 33°-ring of the LMJ(*).
33.2° (10 beams)
49° (10 beams)
59.5° (10 beams)
Z
DT }
(*) Ribeyre X. et al, Plasmas Phys. Cont. Fusion, 51, 015013 (2009).
2D CHIC simulations of bipolar shock ignition show a good sphericity of the ignitor shock.
10CEA-DAM Ile-de-France
0,001
0,01
0,1
1
10
100
1000
0,01 0,1
Et(
MJ)
Ec(MJ)
• The target is far below the ignition threshold.
Fast-ignitor (*) targets can be considered for Shock Ignition (+).
(*) Ribeyre X. et al, Plasmas Phys. Cont. Fusion, 50, 025007 (2008).
(+) Ribeyre X. et al, Plasmas Phys. Cont. Fusion, 51, 015013 (2009)
tspikeP sp
ike
(TW
)
100
200
50
10
20
30
40
10
P (TW)
t (ns)tspike
Pspike
200 ps
300 ps
200 ps
109.5 10.4
DTgas
DT ice@ 250 kg/m3210 µm 1040 µm
HiPER(*) baseline target
1D implosion data Absorbed energy 110 kJ Adiabat 1 Implosion velocity 290 km/s Density Max 600 g/cm3
Areal density max 1.5 g/cm2
0,001
0,01
0,1
1
10
100
1000
0,01 0,1
Et(
MJ)
Ec(MJ)
P=180 TWETh=20 MJ
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With the spike and 2 rings, G1D=50 with 0.2
MJ absorbed laser.
With the spike and 2 rings, G1D=50 with 0.2
MJ absorbed laser.
Marginally igniting standard direct drive target can be triggered by shock ignition (SI).
1 µm CH
DTgas
DT iceWetted foam
120 µm100 µm
960 µm
BaselineDirect Drive
= 3.5 V=400 km/s
50
100
150
7
P (TW)
t (ns)tspike
Pspike
200 ps
300 ps
200 ps
1D implosion data Absorbed energy 200 kJ Density Max 500 g/cm3
Areal density max 1. g/cm2 With SI (@max) Pspike 190 TW Density Max 1700 g/cm3
Areal density max 1.27 g/cm2
Eth 11 MJ
0,01
0,1
1
10
100
0,01 0,1
Eth
erm
onuc
lear
(MJ)
E kinetic
(MJ)
With Shock ignition
12CEA-DAM Ile-de-France
Different targets from the FI-family should be considered for LMJ.100 KJ-absorbed 500 KJ-absorbed
=1v = 290 km/smax= 600 g/cm3
1D implosion data Absorbed energy 500 kJ r 2 g/cm2
Spike Laser Power max 110 TW Abs Intensity 2e15 W/cm2
Thermonuclear rho r 2.2 g/cm2
Energy Th. 133 MJ
850 KJ-absorbed
1D implosion data Absorbed energy 850 kJ r 2.24 g/cm2
Spike Laser Power 100 TW Abs Intensity 1e15 W/cm2
Thermonuclear rho r 2.4 g/cm2
Energy Th. 260 MJ
2090 µm
DTgas
DT ice420 µm
1750 µm
DTgas
DT ice350 µm
1D implosion data Absorbed energy 200 kJ r 1.6 g/cm2
Spike Laser Power 160 TW Abs Intensity 5e15 W/cm2
Thermonuclear rho r 2 g/cm2
Energy Th. 44 MJ
1D implosion data Absorbed energy 100 kJ r 1.2 g/cm2
Spike Laser Power max 120 TW Abs Intensity 6e15 W/cm2
Thermonuclear rho r 1.7 g/cm2
Energy Th. 18 MJ
1040 µm
DTgas
DT ice210 µm
200 KJ-absorbed
1240 µm
DTgas
DT ice250 µm
13CEA-DAM Ile-de-France
The power in the spike is a key parameter for SI.
100 KJ-absorbed
=1v = 290 km/smax= 600 g/cm3
1040 µm
DTgas
DT ice210 µm
200 KJ-absorbed
1240 µm
DTgas
DT ice250 µm
Need between 200 and 300 TWfor ignitor pulses :The 33° rings will produce only 200 TW
We need to redefine a target design and to improve the laser-target coupling efficiency for the ignitor pulses.
1D implosion data Absorbed energy 200 kJ r 1.6 g/cm2
Spike Laser Power 160 TW Abs Intensity 5e15 W/cm2
Thermonuclear r 2 g/cm2
Energy Th. 44 MJ
1D implosion data Absorbed energy 100 kJ r 1.2 g/cm2
Spike Laser Power max 120 TW Abs Intensity 6e15 W/cm2
Thermonuclear r 1.7 g/cm2
Energy Th. 18 MJ
14CEA-DAM Ile-de-France
Low energy for fuel assembly should allow to use only the 49° ring.
100 KJ-absorbed
=1v = 290 km/smax= 600 g/cm3
1D implosion data Absorbed energy 200 kJ r 1.6 g/cm2
Spike Laser Power 160 TW Abs Intensity 5e15 W/cm2
Thermonuclear r 2 g/cm2
Energy Th. 44 MJ
1D implosion data Absorbed energy 100 kJ r 1.2 g/cm2
Spike Laser Power max 120 TW Abs Intensity 6e15 W/cm2
Thermonuclear r 1.7 g/cm2
Energy Th. 18 MJ
1040 µm
DTgas
DT ice210 µm
200 KJ-absorbed
1240 µm
DTgas
DT ice250 µm
b) LMJ Indirect Drive
33.2°
49°59.5°
Z
DT
We need more than 200 kJ to assemble the target: the 49° rings should be a good candidate.
We need to improve the irradiation uniformity.
15CEA-DAM Ile-de-France
High gain direct drive Shock ignition on LMJ requires to address several physical key issues.
Summary
• Standard direct drive fuel assembly is achievable with a part of X drive beams (rings @ 49° et 59°5).• Using the ring @ 49° needs well characterize and to improve (if necessary) the irradiation uniformity (PDD, Green House Target, …)• Shock ignition with the last beams (rings @ 33°) should be possible but we may need to redefine a target with lower power ignitor.• Extremely high gains could be achieved on LMJ :
E1D absorbed~ 0.2 MJ, Eth ~ 40 MJ
Restrictions• Parametric instabilities driven by the shock ignitor could be problematic.• Hydrodynamic stability of the capsule must be addressed• Unknown Physics (eos, heat conductivity, kinetic effects,…) could be limiting.• …
• 1D design must be revisited (wetted foam, reduced IFAR, …).• Fully 2D calculations (with ray-tracing 3D) have to be done for LMJ.
In addition, to be done …