Studying Ignition Schemes on European Laser Facilities

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1 Studying Ignition Schemes on European Laser Facilities S. Jacquemot 23 rd IAEA FEC 11-16/10/2010, Daejeon 23 rd IAEA FEC - 1

2 A dual European horizon 1 - a very-large-scale laser facility: the Laser MégaJoule to 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: HiPER towards Inertial Fusion Energy currently supporting numerical and experimental studies of alternative ignition schemes & innovative technologies 23 rd IAEA FEC - 2

3 The key partners Czech Rep.: FZU/PALS & CTU Prague Phelix France: CEA, LULI, CELIA & LPGP Germany: GSI & MPQ HILL PALS United Kingdom: STFC/RAL Hungary: KFKI RMKI & Szeged Italy: ENEA/Frascati, U. Milano-Bicocca, Roma La Sapienza & ILIL Pisa Poland: IPPLM ABC Portugal: IST/GoLP Spain: CIEMAT & UPM Vulcan LULI rd IAEA FEC - 3

The generic laser-target assembly for LMJ ID ICF polyimid e window Φ~3mm high-z (Au) hohlraum L~1cm, Φ~6mm low-z gas (HHe, <1mg/cc) 3 UV laser cones uniformly doped ablator (e.g. CHGe) R~1.

4 The generic laser-target assembly for LMJ ID ICF polyimid e window Φ~3mm high-z (Au) hohlraum L~1cm, Φ~6mm low-z gas (HHe, <1mg/cc) 3 UV laser cones uniformly doped ablator (e.g. CHGe) R~1.2mm e~160µm solid fuel shell (cryo. DT) e~100µm gaseous DT 0.3mg/cc 550TW / 1.8MJ 3.5MK adequate pulse shaping spherical convergence of accurately timed shock waves isentropic compression & hot spot formation 23 rd IAEA FEC - 4

Current status of the LMJ facility up to

5 Current status of the LMJ facility up to 240 beams in 60 quads, up to 2 MJ/600TW building commissioned, 2(/4) laser bays completed, target chamber being equipped cryo. target assembly under characterization & insertion systems validated PET PCC UTCC Chambre de transfert 1 st experiments end of 2014 J. Ebradt CEA/DAN 23 rd IAEA FEC - 5

Improved target design provides flexibility * cocktail

rugby-shaped hohlraum for a significant x-ray drive

6 Improved target design provides flexibility * cocktail hohlraum (75%U-25%Au) to improve the hohlraum energetics * rugby-shaped hohlraum for a significant x-ray drive enhancement * gradually doped ablator to reduce hydro. risks & control rad. preheating ~3 mm ~10 mm * 160 laser beams in 2 cones 1.2 MJ 330TW C. Cherfils, D. Juraszek CEA/DIF 23 rd IAEA FEC - 6

Laser-Plasma Interaction experiments on the LIL facility give confidence on the effectiveness of the implemented optical smoothing technique to control parametric instabilities 3ω gratings λ

7 Laser-Plasma Interaction experiments on the LIL facility give confidence on the effectiveness of the implemented optical smoothing technique to control parametric instabilities 3ω gratings λ 0 λ 0 + λ 0 L laser beams SRS KDP 1ω gratings 14GHz LEH SBS Reflectivity (%) SRS SBS simul. theo. Intensity [W/cm 2 ] C. Rousseaux CEA/DIF 23 rd IAEA FEC - 7

Rugby-shaped hohlraums allow improving the overall energetics thanks

+25% expected in LMJ conditions experiments on OMEGA (LLE, US)

Rugby Cylinder leading to a record neutron flux (1.

8 Rugby-shaped hohlraums allow improving the overall energetics thanks 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%) Rugby Cylinder leading to a record neutron flux ( ) for a D 2 indirectly-driven F. Philippe CEA/DIF 23 rd IAEA FEC - 8

9 The first 2 shock dynamics has been reproduced on LIL using a LMJrelevant radiation drive VISAR 2ω VISAR ω VDC time 2 nd shock 1 st shock t 0 PS Al F. Philippe CEA/DIF 23 rd IAEA FEC - 9

10 Perspectives: Inertial Fusion Energy (IFE) 3. Driver high repetition rate, low cost good wallplug efficiency & availability 1. Target factory mass production of low-cost targets 2. Target engagement high rep. rate injection, tracking & shooting survivability 4. Fusion scheme robust & simple target design high gain 5. Fusion chamber long lifetime & low activation 6. Steam plant P out ~0.4 GW driver η d 20Hz target G~100 & E d ~600kJ (shock ignition) 23 rd IAEA FEC - 10

11 The HiPER project to demonstrate high repetition rate operation and solve power-production bottlenecks 26 Eu partners in a single facility step PETAL on LMJ: a forerunner to address physics issues C. Edwards STFC, F. Amiranoff LULI, N. Blanchot CEA/CESTA 23rd IAEA FEC - 11

12 ... Preparatory Phase Physics roadmap Technology Developments & Risk Reduction ignition scheme down-select & experimental validation (LMJ/PETAL) Final design & cost analysis construction Technology roadmap 1 & 10 kj beamlines prototyping... reactor concept design. power-to-grid demonstration in ~ 2040 C. Edwards STFC, F. Amiranoff LULI 23 rd IAEA FEC - 12

compression from ignition, using as an external match - either a

13 Alternative ignition schemes allow reducing laser energy requirements fast ignition & shock ignition both rely on decoupling direct drive target compression from ignition, using as an external match - either a laseraccelerated fast particle beam or a strong shock lateral hot spot / central hot spot 23 rd IAEA FEC - 13

An optimized irradiation configuration, using

simulations show that the target ignites despite

nonuniformities reasonable power imbalance &

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 nonuniformities reasonable 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» 23 rd IAEA FEC - 14

15 2D hydro, PIC & transport simulations allow following fast ignition for an asymmetric illumination and investigating influence of the electron beam divergence increase of the ignition energy threshold by a factor ~1/[1-θ r / θ 0 ] A. Debayle, J. Honrubia UPMet al. 23 rd IAEA FEC - 15

First experiments at RAL on electron transport in pre-compressed matter provide valuable

Proton radiography good agreement with numerical simulations (MC code) polyimide cylinder with

1-1 g/cc) fast electron generation 5 x 10 18 W/cm 2 160J/10ps + ps probe beam proton energy

Ni-Kβ HOPG spectrometer Cu-Kα Ni-Kβ max comp.

16 First experiments at RAL on electron transport in pre-compressed matter provide valuable information to benchmark numerical codes Cu foil Ni foil gold shield compression 4x50J / 1ns Proton radiography good agreement with numerical simulations (MC code) polyimide cylinder with CH foam inside (0.1-1 g/cc) fast electron generation 5 x W/cm 2 160J/10ps + ps probe beam proton energy too low X-ray radiography Ni-Kα % of electrons passing through the whole cylinder Cu-Kα / Ni-Kβ HOPG spectrometer Cu-Kα Ni-Kβ max comp. Cu-Kβ time (ns) 100 µm Simulated good agreement with numerical simulations (transmission) Cu-Kα imager (side & rear) detection of fast electrons in compressed matter M. Koenig LULI, D. Batani U. Milano-Bicocca et al. 23 rd IAEA FEC - 16

17 2D hybrid simulations show importance of resistivity gradients t=1.5 ns 1 g/cc t=2 ns 2.5 ns resistivity B field resistivity B field 2D Cu-Kα side fast electrons density 2D Cu-Kα side fast electrons density Very good agreement between experiment and simulations before stagnation: due to resistivity gradients, magnetic fields collimate the fast electron beam at stagnation: the shock converging to the center, the resistivity gradients disappear & the electron beam is no longer collimated F. Perez LULI, A. Debayle UPM 23 rd IAEA FEC - 17

18 Shock ignition leads to higher gain and lower energy threshold for a non-isobaric fuel assembly ε increasing from 1 to 5 m DT =5mg m DT =1mg m DT =0.1mg m DT =0.01mg Spike intensity (PW/cm 2 ) 2MJ compression energy 100kJ Implosion velocity (km/s) Intensity (10 15 W/cm²) parametric instabilities hydro. instabilities 80kJ h = kJ h = MJ h = 2.0 risks due to hydrodynamic and parametric instabilities can be minimized thanks to homothetic scaling of the HiPER target Implosion velocity (km/s) X. Ribeyre et al. CELIA 23 rd IAEA FEC - 18

19 Experiments have already started to investigate LPI and shock formation at PALS & LULI2000 λ t spike I ~ 1015 W/cm2 1st shock I ~ W/cm2 fiducial backscattered light (SBS, SRS) time-resolved CH SiO2 Ti foil SOP t VISAR 1st shock hot electrons 2nd shock t D. Batani U. Milano-Bicocca, P. Koester ILIL Pisa, J. Badziak IPPLM S. Baton LULI et al. 23rd IAEA FEC - 19

The European DPSSL program DPSSL Programs

architecture Germany 150 J @ 0.1Hz 12 J @ 0.

cooled multi-slab France 100 J @ 10Hz 7 J @

gas cooled active mirror UK 1kJ @ 10 Hz none

multi-slab Czech Republic 100 J @ 10Hz & 6J

20 The European DPSSL program DPSSL Programs Goal Achievement Gain medium Amplifier architecture Germany Hz Hz Yb: CaF 2 crystals RT and cryo gas cooled multi-slab France Hz 7 2 Hz Yb:YAG crystals & ceramics RT and cryo gas cooled active mirror UK 10 Hz none Yb:YAG ceramics & glass cryo gas cooled multi-slab Czech Republic Hz & 100Hz none tbd tbd J.-C. Chanteloup 23 rd IAEA FEC - 20

Summary Current experiments and target design improvements give confidence in demonstrating indirectly-driven ignition at ~1 MJ on NIF and then LMJ.

21 Summary Current 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 23 rd IAEA FEC - 21

22 23 rd IAEA FEC - 22

Additional tricks could be employed to further reduce LPI risks and increase safety margins: 2ω operation or plasma-induced beam smoothing LULI2000 creation interaction

23 Additional tricks could be employed to further reduce LPI risks and increase safety margins: 2ω operation or plasma-induced beam smoothing LULI2000 creation interaction time R SBS (%) 1.5 ns 10 3ω creation beam interaction beam CH 50 µm ω LIL (a) W/cm 2 S. Depierreux CEA/DIF, C. Labaune LULI 23 rd IAEA FEC - 23

19 W/cm 2 1ω / 2ω Bremsstrahlung cannons Hard X-ray spectrometer (LCS) Au-Ka & Ag-Ka ω 2ω electrons are less

24 Fast electron transport has been studied on LULI2000 in well-characterized pre-plasmas 2D Cu-Kα imager optical diagnostics HISAC OTR e- / p spectrometer Conical spectrometer Al-Kα & Cu-Kα HOPG Ag-Kα & Cu-Kα 1ps, J W/cm 2 1ω / 2ω Bremsstrahlung cannons Hard X-ray spectrometer (LCS) Au-Ka & Ag-Ka ω 2ω electrons are less divergent in steep-gradient plasmas (at high laser contrast) P. Norreys STFC, S. Baton LULI et al. 23 rd IAEA FEC - 24

Realistic PIC simulations address one of the key issues for this scheme: parametric

time(ps) * transient SBS * absolute local (n c /4-n c /16) SRS associated with

energy transported by 30 kev electrons to the ablation zone high amplitude shock wave

25 Realistic PIC simulations address one of the key issues for this scheme: parametric instabilities spike intensity above threshold SRS & SBS growth observed, but: time(ps) * transient SBS * absolute local (n c /4-n c /16) SRS associated with cavitation SRS SBS strong laser energy absorption ω/ω 0 T cold = 6 kev absorbed energy transported by 30 kev electrons to the ablation zone high amplitude shock wave generated in the dense shell T hot = 29 kev V. Tikhonchuk CELIA, O. Klimo CTU Prague 23 rd IAEA FEC - 25

PALS experiments on shock formation in well-characterized pre-plasma conditions (x-ray deflectometry & spectroscopy) intensity SRS < 5% wavelength (nm) Al CH 20km/s 1keV plasma creation 2 10

26 PALS experiments on shock formation in well-characterized pre-plasma conditions (x-ray deflectometry & spectroscopy) intensity SRS < 5% wavelength (nm) Al CH 20km/s 1keV plasma creation W/cm 2, ω (1.3µm) shock generation W/cm 2, 3ω (0.44µm) next (2011): characterize hot electrons D. Batani U. Milano-Bicocca, P. Koester ILIL Pisa, J. Badziak IPPLM 23 rd IAEA FEC - 26

What is. Inertial Confinement Fusion?

What is. Inertial Confinement Fusion? What is Inertial Confinement Fusion? Inertial Confinement Fusion: dense & short-lived plasma Fusing D and T requires temperature to overcome Coulomb repulsion density & confinement time to maximize number