Post on 28-May-2018
23rd IAEA FEC - 1
Studying Ignition Schemes Studying Ignition Schemes on European Laser Facilitieson European Laser Facilities
S. JacquemotS. Jacquemot
23rd IAEA FEC11-16/10/2010, Daejeon
23rd IAEA FEC - 2
A dual European horizon
1 - a very-large-scale laser facility: the Laser MégaJouleto trustfully demonstrate indirectly-driven laser ignition at the MJ level
thanks to an improved target design & a series of validating experimental campaigns
2 – an ambitious project: HiPERtowards Inertial Fusion Energycurrently supporting numerical and experimental studies ofalternative ignition schemes & innovative technologies
23rd IAEA FEC - 3
� Czech Rep.: FZU/PALS & CTU Prague� France: CEA, LULI, CELIA & LPGP� Germany: GSI & MPQ� United Kingdom: STFC/RAL� Hungary: KFKI RMKI & Szeged� Italy: ENEA/Frascati, U. Milano-Bicocca, Roma “La Sapienza” & ILIL Pisa� Poland: IPPLM� Portugal: IST/GoLP� Spain: CIEMAT & UPM
Vulcan LULI2000
ABC
Phelix
HILL PALS
The key partners
23rd IAEA FEC - 4
The generic laser-target assembly for LMJ ID ICF
3 UV lasercones
high-Z (Au) hohlraum low-Z gas(HHe, <1mg/cc)
L~1cm, Φ~6mm
adequate pulse shaping�
spherical convergence ofaccurately timed shock waves
�isentropic compression & hot spot formation
polyimide windowΦ~3mm
solid fuel shell(cryo. DT) e~100µm
gaseous DT
uniformly doped ablator (e.g. CHGe)e~160µm
0.3mg/ccR~1.2mm
3.5MK550TW / 1.8MJ
23rd IAEA FEC - 5
Current status of the LMJ facilityup to 240 beams in 60 quads, up to 2 MJ/600TW
building commissioned, 2(/4) laser bays completed, target chamber being equippedcryo. target assembly under characterization & insertion systems validated
1st experiments end of 2014
PET
UTCC
PCC
Chambre de transfert
J. Ebradt CEA/DAN
23rd IAEA FEC - 6
* cocktail hohlraum (75%U-25%Au) to improve the hohlraum energetics* rugby-shaped hohlraumfor a significant x-ray driveenhancement
* gradually doped ablatorto reduce hydro. risks &control rad. preheating
* 160 laser beams in 2 cones
Improved target design provides flexibility
� 1.2 MJ – 330TW
C. Cherfils, D. Juraszek CEA/DIF
~10 mm
~3 mm
23rd IAEA FEC - 7
Laser-Plasma Interaction experiments on the LIL facility give confidence on the effectiveness of the implemented optical smoothing techniqueto control parametric instabilities
laser beams
LEH
λ0
λ0 + ∆λ0
∆L3ω gratings
1ω gratingsKDP 14GHz
1014 1015
Intensity [W/cm2]1014 1015
10
1Refle
ctivit
y (%)
0.2
20
SRSSBS
1014 1015
Intensity [W/cm2]1014 1015
10
1Refle
ctivit
y (%)
0.2
20
SRSSBS
C. Rousseaux CEA/DIF
simul. theo.
SRS
SBS
23rd IAEA FEC - 8
Rugby-shaped hohlraums allow improving the overall energeticsthanks to reduction of the wall surface (and thus of the wall losses) up to +25% expected in LMJ conditions
experiments on OMEGA (LLE, US) exhibit a significant increase of the radiative temperature(+16%)
leading to a record neutron flux (1.5 1010) for a D2 indirectly-driven implosion @20kJ
F. Philippe CEA/DIF
RugbyCylinder
23rd IAEA FEC - 9
VISAR 2ω VISAR ω VDC
F. Philippe CEA/DIF
The first 2 shock dynamics has been reproduced on LIL using a LMJ-relevant radiation drive
PS Al
2nd shock
1st shock
t0
time
23rd IAEA FEC - 10
3. Driverhigh repetition rate, low costgood “wallplug” efficiency &availability
4. Fusion schemerobust & simple target designhigh gain
1. Target factorymass production of low-cost targets2. Target engagementhigh rep. rate injection, tracking &shooting – survivability
5. Fusion chamberlong lifetime & low activation
6. Steam plantPout~0.4 GW � driver ηd~20% @ 20Hz � target G~100 & Ed~600kJ(shock ignition)
Perspectives: Inertial Fusion Energy (IFE)
23rd IAEA FEC - 11
The HiPER projectto demonstrate high repetition rate operation and solve power-production bottlenecks
in a single facility stepPETAL on LMJ:a forerunner to addressphysics issues
26 Eu partners
C. Edwards STFC, F. Amiranoff LULI, N. Blanchot CEA/CESTA
23rd IAEA FEC - 12
Preparatory Phase
Physics roadmapignition scheme down-select &
experimental validation (LMJ/PETAL)
1 & 10 kJ beamlines prototyping
Final design & cost analysis
Technology Developments & Risk Reduction
Technology roadmap
reactor concept design.
.
.
.
� power-to-grid demonstration in ~ 2040
...
� construction
C. Edwards STFC, F. Amiranoff LULI
23rd IAEA FEC - 13
Alternative ignition schemes allow reducing laser energy requirementsfast ignition & shock ignition both rely on decoupling direct drive target compression from ignition, using – as an external match - either a laser-accelerated fast particle beam or a strong shock
lateral hot spot / central hot spotlateral hot spot / central hot spot
23rd IAEA FEC - 14
An optimized irradiation configuration, using only 48 laser beams, has been found
2D multimode simulations show that the target ignites despite capsule deformation due to illumination non-uniformitiesreasonable power imbalance & pointing error can be borne if focal spot carefully optimized
M. Temporal UPM, B. Canaud CEA/DIF et al., S. Atzeni U. Rome « La Sapienza »
23rd IAEA FEC - 15
2D hydro, PIC & transport simulations allow following fast ignition for an asymmetric illumination
A. Debayle, J. Honrubia UPMet al.
and investigating influence of the electron beam divergence
increase of the ignition energy thresholdby a factor ~1/[1-θr/∆θ0]
23rd IAEA FEC - 16
First experiments at RAL on electron transport in pre-compressed matter provide valuable information to benchmark numerical codes
M. Koenig LULI, D. Batani U. Milano-Bicocca et al.
% of electrons passing throughthe whole cylinder
5 x 1018 W/cm2
160J/10ps
compression4x50J / 1ns
fast electron generationpolyimide cylinder with CH foam inside
(0.1-1 g/cc)
Proton radiography
X-ray radiography+ ps probe beam
good agreement with numerical simulations (MC code)gold shield
proton energy too low
Simulated
good agreement with numerical simulations (transmission)
Ni foilCu foil
Ni-Kαααα Ni-KββββCu-Kαααα Cu-Kββββ
HOPG spectrometer
Cu-Kα imager (side & rear)
detection of fast electrons in compressed matter
Cu-K
α/ N
i-Kβ
max comp.time (ns)
100 µm
23rd IAEA FEC - 17F. Perez LULI, A. Debayle UPM
1 g/cc1 g/cc2.5 ns
B field
fast electrons density
resistivity
2D Cu-Kα side
before stagnation: due to resistivity gradients, magnetic fields collimate the fast electron beamat stagnation: the shock converging to the center, the resistivity gradients disappear & the electron beam is no longer collimated
2D Cu-Kα side fast electrons density
B fieldresistivity
t=1.5 ns t=2 ns
Very good agreement between experiment and simulations
2D hybrid simulations show importance of resistivitygradients
23rd IAEA FEC - 18
Shock ignition leads to higher gain and lower energy threshold for a non-isobaric fuel assembly
mDT=0.01mg
mDT=0.1mg
mDT=1mg
ε increasing from 1 to 5mDT=5mg
mDT=0.01mg
mDT=0.1mg
mDT=1mg
ε increasing from 1 to 5mDT=5mg
X. Ribeyre et al. CELIA
Intens
ity(10
15W/
cm²) parametric instabilities hydro. instabilities
80kJ
1.5MJ
250kJ
h = 2.0
Implosion velocity (km/s)
risks due to hydrodynamic and parametric instabilities can be minimized thanks to homothetic scaling of the HiPER targeth = 0.5
h = 1.0
Implosion velocity (km/s)
Spike
inten
sity(
PW/cm
2 )
compression energy100kJ
2MJ
23rd IAEA FEC - 19
Experiments have already started to investigate LPI and shock formation at PALS & LULI2000
D. Batani U. Milano-Bicocca, P. Koester ILIL Pisa, J. Badziak IPPLM – S. Baton LULI et al.
backscattered light (SBS, SRS)time-resolved
1st shockI ~ 51013 W/cm2
“spike”I ~ 1015 W/cm2
VISAR
SOP
hot electrons
CH
Ti foil
SiO2CH
Ti foil
SiO2
tλ
ttλ
fiducial
1st shock
2nd shock
tt
tt
23rd IAEA FEC - 20
The European DPSSL program
100 J @ 10Hz & 6J @ 100Hz
none
1kJ @ 10 Hznone
100 J @ 10Hz7 J @ 2 Hz
150 J @ 0.1Hz12 J @ 0.003 Hz
Goal AchievementDPSSL Programs Gain medium Amplifier
architectureGermany
Yb: CaF2crystalsRT° and cryo gas cooled multi-slab
FranceYb:YAG
crystals & ceramicsRT° and cryo gas cooled active
mirrorUK
Yb:YAGceramics & glass
cryo gas cooled multi-slab
Czech Republictbd tbd
100 J @ 10Hz & 6J @ 100Hz
none
1kJ @ 10 Hznone
100 J @ 10Hz7 J @ 2 Hz
150 J @ 0.1Hz12 J @ 0.003 Hz
Goal AchievementDPSSL Programs Gain medium Amplifier
architectureGermany
Yb: CaF2crystalsRT° and cryo gas cooled multi-slab
FranceYb:YAG
crystals & ceramicsRT° and cryo gas cooled active
mirrorUK
Yb:YAGceramics & glass
cryo gas cooled multi-slab
Czech Republictbd tbd
J.-C. Chanteloup
23rd IAEA FEC - 21
SummaryCurrent experiments and target design improvements give confidence in demonstrating indirectly-driven ignition at ~1 MJ on NIF and then LMJ.It will be a major step towards determining the feasibility of ICF as an energy source.In the framework of the EURATOM keep-in-touch & the HiPER programs Europe has launched coordinated studies to: (i) choose the most suitable ignition scheme, thanks to innovative experiments and 2D numerical simulations, (ii) improve DPSSL driver and target technologies. with the support of LASERLAB-Europe for transnational access to laser facilities
23rd IAEA FEC - 23
Additional tricks could be employed to further reduce LPI risks and increase safety margins: 2ω operation or plasma-induced beam smoothing
0611030
creationbeam
interaction beam
CH50 µm
time
1.5 ns
creation interaction
0611030
creationbeam
interaction beam
CH50 µm
time
1.5 ns
creation interaction
(a)
LULI2000
LIL
S. Depierreux CEA/DIF, C. Labaune LULI
0 1 2 3 1015 W/cm2
3ω
RSBS(%)
10
1
0 1 2 3 1015 W/cm2
3ω
2ω
RSBS(%)
10
1
23rd IAEA FEC - 24
Fast electron transport has been studied on LULI2000 in well-characterized pre-plasmas
P. Norreys STFC, S. Baton LULI et al.
electrons are less divergent in steep-gradient plasmas (at high laser contrast)
2D Cu-Kα imager
HOPGAg-Kα & Cu-Kα
Conical spectrometerAl-Kα & Cu-Kα
Bremsstrahlung cannons
e- / p spectrometer
Hard X-ray spectrometer (LCS) Au-Ka & Ag-Ka
optical diagnostics• HISAC• OTR
1ps , 25-40 J1019 W/cm2
1ω / 2ω
2D Cu-Kα imager
HOPGAg-Kα & Cu-Kα
Conical spectrometerAl-Kα & Cu-Kα
Bremsstrahlung cannons
e- / p spectrometer
Hard X-ray spectrometer (LCS) Au-Ka & Ag-Ka
optical diagnostics• HISAC• OTR
1ps , 25-40 J1019 W/cm2
1ω / 2ω
ω 2ω
23rd IAEA FEC - 25
Realistic PIC simulations address one of the key issues for this scheme: parametric instabilities
V. Tikhonchuk CELIA, O. Klimo CTU Prague
ω/ω0
time(p
s)
SBSSRS
spike intensity above threshold� SRS & SBS growth observed, but:* transient SBS* absolute local (nc/4-nc/16) SRS associated with cavitation� strong laser energy absorption
Tcold = 6 kev
Thot = 29 kev
absorbed energy transported by 30 keVelectrons to the ablation zone� high amplitude shock wave generated in the dense shell
23rd IAEA FEC - 26
PALS experiments on shock formationin well-characterized pre-plasma conditions (x-ray deflectometry & spectroscopy)
D. Batani U. Milano-Bicocca, P. Koester ILIL Pisa, J. Badziak IPPLM
1keV plasma creation2 1013W/cm2, ω (1.3µm)
shock generation5 1015W/cm2, 3ω (0.44µm)
Al CH
wavelength (nm)
inten
sity
SRS < 5%
wavelength (nm)
inten
sity
SRS < 5%
20km/s20km/s
next (2011): characterize hot electrons
20km/s
SRS < 5%