Publications

2022

• Hugoniot and released state of calcite above 200 GPa with implications for hypervelocity planetary impacts
  
  • Umeda Yuhei
  • Fukui Keiya
  • Sekine Toshimori
  • Guarguaglini Marco
  • Benuzzi-Mounaix Alessandra
  • Kamimura Nobuki
  • Katagiri Kento
  • Kodama Ryosuke
  • Matsuoka Takeshi
  • Miyanishi Kohei
  • Ravasio Alessandra
  • Sano Takayoshi
  • Ozaki Norimasa
  Icarus, Elsevier, 2022, 377, pp.114901. Carbonate minerals, for example calcite and magnesite, exist on the planetary surfaces of the Earth, Mars, and Venus, and are subjected to hypervelocity collisions. The physical properties of planetary materials at extreme conditions are essential for understanding their dynamic behaviors at hypervelocity collisions and the mantle structure of rocky planets including Super-Earths. Here we report laboratory investigations of laser-shocked calcite at pressures of 200-960 GPa (impact velocities of 12-30 km/s and faster than escape velocity from the Earth) using decay shock techniques. Our measured temperatures above 200 GPa indicated a large difference from the previous theoretical models. The present shock Hugoniot data and temperature measurements, compared with the previous reports, indicate melting without decomposition at pressures of ~110 GPa to ~350 GPa and a bonded liquid up to 960 GPa from the calculated specific heat. Our temperature calculations of calcite at 1 atm adiabatically released from the Hugoniot points suggest that the released products vary depending on the shock pressures and affect the planetary atmosphere by the degassed species. The present results on calcite newly provide an important anchor for considering the theoretical EOS at the extreme conditions, where the model calculations show a significant diversity at present. (10.1016/j.icarus.2022.114901)
  DOI : 10.1016/j.icarus.2022.114901
• Far field energy distribution control with a coherent beam combining femtosecond digital laser
  
  • Ranély-Vergé-Dépré Claude-Alban
  • Veinhard Matthieu
  • Bellanger Séverine
  • Fsaifes Ihsan
  • Chanteloup Jean-Christophe
  , 2022, PC1198109, pp.23. We report on far field energy distribution control using a coherent beam combining femtosecond digital laser employing 61 tiled channels. Each channel is considered as an individual pixel where amplitude and phase are controlled independently. Applying a phase difference between neighboring fibers or neighboring fiber-lines gives high agility for a far field energy distribution and paves the way for deeper exploration of phase patterns as a tool to further improve the efficiency achievable with tiled-aperture/filled-aperture setups and far field shaping on demand. (10.1117/12.2614759)
  DOI : 10.1117/12.2614759
• Laser driven nuclear physics at ELI-NP
  
  • Negoita F.
  • Roth M.
  • Thirolf P.G.
  • Tudisco S.
  • Hannachi F.
  • Moustaizis S.
  • Pomerantz I.
  • Mckenna P.
  • Fuchs J.
  • Sphor K.
  • Acbas G.
  • Anzalone A.
  • Audebert P.
  • Balascuta S.
  • Cappuzzello F.
  • Cernaianu M.O.
  • Chen S.
  • Dancus I.
  • Freeman R.
  • Geissel H.
  • Ghenuche P.
  • Gizzi L.
  • Gobet F.
  • Gosselin G.
  • Gugiu M.
  • Higginson D.
  • d'Humiêres E.
  • Ivan C.
  • Jaroszynski D.
  • Kar S.
  • Lamia L.
  • Leca V.
  • Neagu L.
  • Lanzalone G.
  • Meot V.
  • Mirfayzi S.R.
  • Mitu I.O.
  • Morel P.
  • Murphy C.
  • Petcu C.
  • Petrascu H.
  • Petrone C.
  • Raczka P.
  • Risca M.
  • Rotaru F.
  • Santos J.J.
  • Schumacher D.
  • Stutman D.
  • Tarisien M.
  • Tataru M.
  • Tatulea B.
  • Turcu I.C.E.
  • Versteegen M.
  • Ursescu D.
  • Gales S.
  • Zamfir N.V.
  , 2022. High power lasers have proven being capable to produce high energy Ȗ-rays, charged particles and neutrons, and to induce all kinds of nuclear reactions. At ELI, the studies with high power lasers will enter for the first time into new domains of power and intensities: 10 PW and 1023 W/cm2. While the development of laser based radiation sources is the main focus at the ELI-Beamlines pillar of ELI, at ELINP the studies that will benefit from High Power Laser System pulses will focus on Laser Driven Nuclear Physics (this TDR, acronym LDNP, associated to the E1 experimental area), High Field Physics and QED (associated to the E6 area) and fundamental research opened by the unique combination of the two 10 PW laser pulses with a gamma beam provided by the Gamma Beam System (associated to E7 area). The scientific case of the LDNP TDR encompasses studies of laser induced nuclear reactions, aiming for a better understanding of nuclear properties, of nuclear reaction rates in laser-plasmas, as well as on the development of radiation source characterization methods based on nuclear techniques. As an example of proposed studies: the promise of achieving solid-state density bunches of (very) heavy ions accelerated to about 10 MeV/nucleon through the RPA mechanism will be exploited to produce highly astrophysical relevant neutron rich nuclei around the N~126 waiting point, using the sequential fission-fusion scheme, complementary to any other existing or planned method of producing radioactive nuclei. The studies will be implemented predominantly in the E1 area of ELI-NP. However, many of them can be, in a first stage, performed in the E5 and/or E4 areas, where higher repetition laser pulses are available, while the harsh X-ray and electromagnetic pulse (EMP) environments are less damaging compared to E1. A number of options are discussed through the document, having an important impact on the budget and needed resources. Depending on the TDR review and subsequent project decisions, they may be taken into account for space reservation, while their detailed design and implementation will be postponed. The present TDR is the result of contributions from several institutions engaged in nuclear physics and high power laser research. A significant part of the proposed equipment can be designed, and afterwards can be built, only in close collaboration with (or subcontracting to) some of these institutions. A Memorandum of Understanding (MOU) is currently under preparation with each of these key partners as well as with others that are interested to participate in the design or in the future experimental program.
• Simple adaptations to speed-up the Particle-In-Cell code Smilei on the ARM-based Fujitsu A64FX processor
  
  • Lobet Mathieu
  • Massimo Francesco
  • Beck Arnaud
  • Bouchard Guillaume
  • Perez Frederic
  • Vinci Tommaso
  • Grech Mickael
  , 2022, pp.40-48. We present in a simple and pedagogic way the preliminary code adaptation made in the C++ parallel Particle-In-Cell code Smilei to speed-up vectorized algorithms for the Fujitsu ARM-based A64FX processor. We analyze the performance of Smilei on A64FX compiling with the GNU, ARM and Fujitsu compilers and we compare with the Intel Skylake, Intel Cascadelake and AMD Rome processors. (10.1145/3503470.3503475)
  DOI : 10.1145/3503470.3503475
• Spectral broadening for multi-Joule pulse compression in the APOLLON Long Focal Area facility
  
  • Bleotu P.-G.
  • Wheeler J.
  • Papadopoulos D.
  • Chabanis M.
  • Prudent J.
  • Frotin M.
  • Martin L.
  • Lebas N.
  • Freneaux A.
  • Beluze A.
  • Mathieu F.
  • Audebert P.
  • Ursescu D.
  • Fuchs J.
  • Mourou G.
  High Power Laser Science and Engineering, Cambridge University Press, 2022, 10, pp.e9. Spectral-broadening of the APOLLON PW-class laser pulses using a thin-film compression technique within the long-focal-area interaction chamber of the APOLLON laser facility is reported, demonstrating the delivery of the full energy pulse to the target interaction area. The laser pulse at 7 J passing through large aperture, thin glass wafers is spectrally broadened to a bandwidth that is compatible with a 15-fs pulse, indicating also the possibility to achieve sub-10-fs pulses using 14 J. Placing the post-compressor near the interaction makes for an economical method to produce the shortest pulses by limiting the need for high damage, broadband optics close to the final target rather than throughout the entire laser transport system. (10.1017/hpl.2021.61)
  DOI : 10.1017/hpl.2021.61
• Detailed characterization of laboratory magnetized super-critical collisionless shock and of the associated proton energization
  
  • Yao W.
  • Fazzini A.
  • Chen S. N.
  • Burdonov K.
  • Antici P.
  • Béard J.
  • Bolaños S.
  • Ciardi A.
  • Diab R.
  • Filippov E. D.
  • Kisyov S.
  • Lelasseux V.
  • Miceli M.
  • Moreno Q.
  • Nastasa V.
  • Orlando S.
  • Pikuz S.
  • Popescu D. C.
  • Revet G.
  • Ribeyre X.
  • D’humières E.
  • Fuchs J.
  Matter and Radiation at Extremes, AIP Publishing, 2022, 7 (1), pp.014402. Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of non-thermal particles and high-energy radiation. In the absence of particle collisions in the system, theoretical works show that the interaction of an expanding plasma with a pre-existing electromagnetic structure (as in our case) is able to induce energy dissipation and allow for shock formation. Shock formation can alternatively take place when two plasmas interact, through microscopic instabilities inducing electromagnetic fields which are able in turn to mediate energy dissipation and shock formation. Using our platform where we couple a fast expanding plasma induced by high-power lasers (JLF/Titan at LLNL and LULI2000) with high-strength magnetic fields, we have investigated the generation of magnetized collisionless shock and the associated particle energization. We have characterized the shock to be collisionless and super-critical. We report here on measurements of the plasma density, temperature, the electromagnetic field structures, and particle energization in the experiments, under various conditions of ambient plasma and B-field. We have also modelled the formation of the shocks using macroscopic hydrodynamic simulations and the associated particle acceleration using kinetic particle-in-cell simulations. As a companion paper of \citet{yao2020laboratory}, here we show additional results of the experiments and simulations, providing more information to reproduce them and demonstrating the robustness of our interpreted proton energization mechanism to be shock surfing acceleration. (10.1063/5.0055071)
  DOI : 10.1063/5.0055071
• Laboratory modelling of equatorial ‘tongue’ accretion channels in young stellar objects caused by the Rayleigh-Taylor instability
  
  • Burdonov Konstantin
  • Yao Weipeng
  • Sladkov Andrey
  • Bonito Rosaria
  • Chen Sophia N
  • Ciardi Andrea
  • Korzhimanov Artem
  • Soloviev Alexander
  • Starodubtsev Mikhail V.
  • Zemskov Roman
  • Orlando Salvatore
  • Romanova Marina
  • Fuchs Julien
  Astronomy & Astrophysics - A&A, EDP Sciences, 2022, 657, pp.A112. Context. The equatorial accretion scenario, caused by the development of the Rayleigh-Taylor (RT) instability at the disk edge, was suggested by accurate three-dimensional magnetohydrodynamic (MHD) modelling, but no observational or experimental confirmation of such phenomena has been evidenced yet.Aims. We studied the propagation of a laterally extended laser-generated plasma stream across a magnetic field and investigated if this kind of structure can be scaled to the case of equatorial ‘tongue’ accretion channels in young stellar objects (YSOs); if so, this would support the possibility of equatorial accretion in young accreting stars.Methods. We conducted a scaled laboratory experiment at the PEARL laser facility. The experiment consists in an optical laser pulse that is focused onto the surface of a Teflon target. The irradiation of the target leads to the expansion of a hot plasma stream into the vacuum, perpendicularly to an externally applied magnetic field. We used a Mach-Zehnder interferometer to diagnose the plasma stream propagation along two axes, to obtain the three-dimensional distribution of the plasma stream.Results. The laboratory experiment shows the propagation of a laterally extended laser-generated plasma stream across a magnetic field. We demonstrate that: (i) such a stream is subject to the development of the RT instability, and (ii) the stream, decomposed into tongues, is able to efficiently propagate perpendicular to the magnetic field. Based on numerical simulations, we show that the origin of the development of the instability in the laboratory is similar to that observed in MHD models of equatorial tongue accretion in YSOs.Conclusions. As we verify that the laboratory plasma scales favourably to accretion inflows of YSOs, our laboratory results support the argument in favour of the possibility of the RT-instability-caused equatorial tongue accretion scenario in the astrophysical case. (10.1051/0004-6361/202140997)
  DOI : 10.1051/0004-6361/202140997
• Ultrafast fiber technologies for compact laser wake field in medical application
  
  • Sha Weijian
  • Chanteloup Jean-Christophe
  • Mourou Gérard
  Photonics, MDPI, 2022, 9 (6), pp.423. Technologies, performances and maturity of ultrafast fiber lasers and fiber delivery of ultrafast pulses are discussed for the medical deployment of laser-wake-field acceleration (LWFA). The compact ultrafast fiber lasers produce intense laser pulses with flexible hollow-core fiber delivery to facilitate electron acceleration in the laser-stimulated wake field near treatment site, empowering endoscopic LWFA brachytherapy. With coherent beam combination of multiple fiber amplifiers, the advantages of ultrafast fiber lasers are further extended to bring in more capabilities in compact LWFA applications (10.3390/photonics9060423)
  DOI : 10.3390/photonics9060423
• Laboratory evidence of magnetic reconnection hampered in obliquely interacting flux tubes
  
  • Bolaños Simon
  • Sladkov Andrey
  • Riquier Raphël
  • Smets Roch
  • Chen Sophia
  • Grisollet Alain
  • Filippov Evgeny
  • Henares Jose-Luis
  • Nastasa Viorel
  • Pikuz Sergey
  • Safronova Maria
  • Severin Alexandre
  • Starodubtsev Mikhail
  • Fuchs Julien
  Nature Communications, Nature Publishing Group, 2022, 13 (1), pp.6426. Magnetic reconnection can occur when two plasmas, having anti-parallel components of the magnetic field, encounter each other. In the reconnection plane, the anti-parallel component of the field is annihilated and its energy released in the plasma. Here, we investigate through laboratory experiments the reconnection between two flux tubes that are not strictly anti-parallel. Compression of the anti-parallel component of the magnetic field is observed, as well as a decrease of the reconnection efficiency. Concomitantly, we observe delayed plasma heating and enhanced particle acceleration. Three-dimensional hybrid simulations support these observations and highlight the plasma heating inhibition and reconnection efficiency reduction for these obliquely oriented flux tubes. (10.1038/s41467-022-33813-9)
  DOI : 10.1038/s41467-022-33813-9
• Compressing High Energy Lasers through Optical Polymer Films
  
  • Wheeler Jonathan
  • Bleotu Gabriel Petrisor
  • Naziru Andrei
  • Fabbri Riccardo
  • Masruri Masruri
  • Secareanu Radu
  • Farinella Deano M.
  • Cojocaru Gabriel
  • Ungureanu Razvan
  • Baynard Elsa
  • Demailly Julien
  • Pittman Moana
  • Dabu Razvan
  • Dancus Ioan
  • Ursescu Daniel
  • Ros David
  • Tajima Toshiki
  • Mourou Gerard
  Photonics, MDPI, 2022, 9 (10), pp.715. <jats:p>The thin-film post-compression technique has the ability to reduce the pulse duration in PW-class lasers, increasing the peak power. Here, the nonlinear response of an increasingly available optical thermoplastic demonstrates enhanced spectral broadening, with corresponding shorter pulse duration compared to fused silica glass. The thermoplastic can be used close to its damage threshold when refreshed using a roller mechanism, and the total amount of material can be varied by folding the film. As a proof-of-principle demonstration scalable to 10-PW, a roller mechanism capable of up to 6 passes through a sub-millimeter thermoplastic film is used in vacuum to produce two-fold post-compression of the pulse. The compact design makes it an ideal method to further boost ultrahigh laser pulse intensities with benefits to many areas, including driving high energy acceleration.</jats:p> (10.3390/photonics9100715)
  DOI : 10.3390/photonics9100715
• High pressure dissociation of CaTiO3 perovskite into CaO and CaTi2O5
  
  • Truffet B
  • Fiquet G
  • Morard G
  • Baron M A
  • Miozzi F
  • Harmand M
  • Ravasio A
  • Mezouar M
  • Guyot F
  Physics of the Earth and Planetary Interiors, Elsevier, 2022. In this study, we investigated phase transformations of CaTiO3 perovskite using x-ray diffraction at high pressure and high temperature up to 170 GPa and 4500 K in a laser-heated diamond-anvil cell. We report a high-pressure dissociation of CaTiO3 into CaO-B2 and CaTi2O5 with a monoclinic P2/m structure, instead of the expected transformation of the orthorhombic distorted perovskite structure into a post-perovskite phase. We propose that this transition may be favored by the B1 to B2 phase change of CaO at around 60 GPa. In order to provide additional information on the high pressure properties of CaTiO3 perovskite, we measured its melting temperature using CO2 laser heated diamond anvil cell up to 55 GPa yielding a fit of the melting curve to a Kraut-Kennedy empirical law according to: Tm(K) = 2188 ∗ [1 + 4.23 ∗ (ΔV/V0)]. To provide some further insight into the thermodynamic properties of CaTiO3, we determined the P-V-T equation of state of the orthorhombic mineral perovskite, fitted by using a third order Birch-Murnaghan equation of state and a Berman thermal expansion model. The fit of the data yields to K0 = 180.6(4) GPa, K′0 = 4 (fixed), ∂K/∂T = −0.022(1) GPa K−1, α1 = 3.25(5) x 10−5 K−1, α2 = 1.3(1) x 10−8 K−2 (10.1016/j.pepi.2022.106968)
  DOI : 10.1016/j.pepi.2022.106968
• Phase noise measurements and diagnoses of a large array of fiber lasers by PISTIL
  
  • Rouzé Bastien
  • Fsaifes Ihsan
  • Bellanger Severine
  • Veinhard Matthieu
  • Rousseaux Thomas
  • Primot Jérome
  • Chanteloup Jean-Christophe
  • Bellanger Cindy
  Applied optics, Optical Society of America, 2022, 61 (27), pp.7846. One of the most promising solutions to access high power laser chains is to achieve a coherent combination of a large number of elementary lasers. To interfere constructively, these laser sources should be identical and operate under the same conditions. However, despite these efforts, differential delays appear in the course of time, which must be compensated for. While designing the required correction system, knowing the behavior of a laser as a function of the environmental conditions is not crucial, whereas having access to the differences in the behaviors of identical lasers is, leading to difficulties in modeling. The purpose of this paper is to illustrate how a large set of lasers can be simultaneously analyzed to estimate their variations and optimize a correction system. The X-Coherent Amplified Network laser relies on 61 fiber amplifiers, which are as identical as possible. This state of the art femtosecond digital laser therefore appears as an ideal candidate to study a large number of fiber lasers working under controlled conditions. (10.1364/AO.466021)
  DOI : 10.1364/AO.466021
• Enhancement of the Nonresonant Streaming Instability by Particle Collisions
  
  • Marret Alexis
  • Ciardi Andrea
  • Smets Roch
  • Fuchs Julien
  • Nicolas Loic
  Physical Review Letters, American Physical Society, 2022, 128 (11), pp.115101. Streaming cosmic rays can power the exponential growth of a seed magnetic field by exciting a nonresonant instability that feeds on their bulk kinetic energy. By generating the necessary turbulent magnetic field, it is thought to play a key role in the confinement and acceleration of cosmic rays at shocks. In this Letter we present hybrid-particle-in-cell simulations of the nonresonant mode including Monte Carlo collisions, and investigate the interplay between the pressure anisotropies produced by the instability and particle collisions in the background plasma. Simulations of poorly ionized plasmas confirm the rapid damping of the instability by proton-neutral collisions predicted by linear fluid theory calculations. In contrast we find that Coulomb collisions in fully ionized plasmas do not oppose the growth of the magnetic field, but under certain conditions suppress the pressure anisotropies and actually enhance the magnetic field amplification. (10.1103/PhysRevLett.128.115101)
  DOI : 10.1103/PhysRevLett.128.115101
• Transient Relativistic Plasma Grating to Tailor High-Power Laser Fields, Wakefield Plasma Waves, and Electron Injection
  
  • Chen Qiang
  • Maslarova Dominika
  • Wang Junzhi
  • Lee Shao Xian
  • Horný Vojtech
  • Umstadter Donald
  Physical Review Letters, American Physical Society, 2022, 128 (16), pp.164801. We show the first experiment of a transverse laser interference for electron injection into the laser plasma accelerators. Simulations show such an injection is different from previous methods, as electrons are trapped into later acceleration buckets other than the leading ones. With optimal plasma tapering, the dephasing limit of such unprecedented electron beams could be potentially increased by an order of magnitude. In simulations, the interference drives a relativistic plasma grating, which triggers the splitting of relativistic-intensity laser pulses and wakefield. Consequently, spatially dual electron beams are accelerated, as also confirmed by the experiment. (10.1103/PhysRevLett.128.164801)
  DOI : 10.1103/PhysRevLett.128.164801
• Hydrodynamic instabilities in a highly radiative environment
  
  • Rigon G.
  • Albertazzi B.
  • Mabey P.
  • Michel Th.
  • Barroso P.
  • Faenov A.
  • Kumar R.
  • Michaut Claire
  • Pikuz T.
  • Sakawa Y.
  • Sano T.
  • Shimogawara H.
  • Tamatani S.
  • Casner A.
  • Koenig M.
  Physics of Plasmas, American Institute of Physics, 2022, 29 (7), pp.072106. In this paper, we present the effects of a radiative shock (RS) on the morphology of jet-like objects subjected to hydrodynamic instabilities. To this end, we used an experimental platform developed to create RSs on high energy laser facilities such as LULI2000 and GEKKO XII. Here, we employed modulated targets to initiate Richtmyer–Meshkov and Rayleigh–Taylor instability (RTI) growth in the presence of an RS. The RS is obtained by generating a strong shock in a dense pusher that expands into a low-density xenon gas. With our design, only a limited RTI growth occurs in the absence of radiative effects. A strongly radiative shock has opposite effects on RTI growth. While its deceleration enhances the instability growth, the produced radiations tend to stabilize the interfaces. Our indirect experimental observations suggest a lower instability growth despite the interface deceleration. In addition, the jets, produced during the experiment, are relevant to astrophysical structures such as Herbig–Haro objects or other radiatively cooling jets. (10.1063/5.0089994)
  DOI : 10.1063/5.0089994
• Cylindrical implosion platform for the study of highly magnetized plasmas at Laser MegaJoule
  
  • Pérez-Callejo G.
  • Vlachos C.
  • Walsh C.A.
  • Florido R.
  • Bailly-Grandvaux M.
  • Vaisseau X.
  • Suzuki-Vidal F.
  • Mcguffey C.
  • Beg F.N.
  • Bradford P.
  • Ospina-Bohórquez V.
  • Batani D.
  • Raffestin D.
  • Colaïtis A.
  • Tikhonchuk V.
  • Casner A.
  • Koenig M.
  • Albertazzi B.
  • Fedosejevs R.
  • Woolsey N.
  • Ehret M.
  • Debayle A.
  • Loiseau P.
  • Calisti A.
  • Ferri S.
  • Honrubia J.
  • Kingham R.
  • Mancini R.C.
  • Gigosos M.A.
  • Santos J.J.
  Physical Review E, American Physical Society (APS), 2022, 106 (3), pp.035206. Investigating the potential benefits of the use of magnetic fields in inertial confinement fusion experiments has given rise to experimental platforms like the Magnetized Liner Inertial Fusion approach at the Z-machine (Sandia National Laboratories) or its laser-driven equivalent at OMEGA (Laboratory for Laser Energetics). Implementing these platforms at MegaJoule-scale laser facilities, such as the Laser MegaJoule (LMJ) or the National Ignition Facility (NIF), is crucial to reaching self-sustained nuclear fusion and enlarges the level of magnetization that can be achieved through a higher compression. In this paper, we present a complete design of an experimental platform for magnetized implosions using cylindrical targets at LMJ. A seed magnetic field is generated along the axis of the cylinder using laser-driven coil targets, minimizing debris and increasing diagnostic access compared with pulsed power field generators. We present a comprehensive simulation study of the initial B field generated with these coil targets, as well as two-dimensional extended magnetohydrodynamics simulations showing that a 5 T initial B field is compressed up to 25 kT during the implosion. Under these circumstances, the electrons become magnetized, which severely modifies the plasma conditions at stagnation. In particular, in the hot spot the electron temperature is increased (from 1 keV to 5 keV) while the density is reduced (from <math><mrow><mn>40</mn><mspace width="0.16em"/><msup><mrow><mi mathvariant="normal">g</mi><mo>/</mo><mi>cm</mi></mrow><mn>3</mn></msup></mrow></math> to <math><mrow><mn>7</mn><mspace width="0.16em"/><msup><mrow><mi mathvariant="normal">g</mi><mo>/</mo><mi>cm</mi></mrow><mn>3</mn></msup></mrow></math>). We discuss how these changes can be diagnosed using x-ray imaging and spectroscopy, and particle diagnostics. We propose the simultaneous use of two dopants in the fuel (Ar and Kr) to act as spectroscopic tracers. We show that this introduces an effective spatial resolution in the plasma which permits an unambiguous observation of the B-field effects. Additionally, we present a plan for future experiments of this kind at LMJ. (10.1103/PhysRevE.106.035206)
  DOI : 10.1103/PhysRevE.106.035206
• Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas
  
  • Meinecke J.
  • Tzeferacos P.
  • Ross J.S.
  • Bott A.F.A.
  • Feister S.
  • Park H.-S.
  • Bell A.R.
  • Blandford R.
  • Berger R.L.
  • Bingham R.
  • Casner A.
  • Chen L.E.
  • Foster J.
  • Froula D.H.
  • Goyon C.
  • Kalantar D.
  • Koenig M.
  • Lahmann B.
  • Li C.-K.
  • Lu Y.
  • Palmer C.A.J.
  • Petrasso R.
  • Poole H.
  • Remington B.
  • Reville B.
  • Reyes A.
  • Rigby A.
  • Ryu D.
  • Swadling G.
  • Zylstra A.
  • Miniati F.
  • Sarkar S.
  • Schekochihin A.A.
  • Lamb D.Q.
  • Gregori G.
  Science Advances, American Association for the Advancement of Science (AAAS), 2022, 8 (10), pp.abj6799. In conventional gases and plasmas, it is known that heat fluxes are proportional to temperature gradients, with collisions between particles mediating energy flow from hotter to colder regions and the coefficient of thermal conduction given by Spitzer’s theory. However, this theory breaks down in magnetized, turbulent, weakly collisional plasmas, although modifications are difficult to predict from first principles due to the complex, multiscale nature of the problem. Understanding heat transport is important in astrophysical plasmas such as those in galaxy clusters, where observed temperature profiles are explicable only in the presence of a strong suppression of heat conduction compared to Spitzer’s theory. To address this problem, we have created a replica of such a system in a laser laboratory experiment. Our data show a reduction of heat transport by two orders of magnitude or more, leading to large temperature variations on small spatial scales (as is seen in cluster plasmas). (10.1126/sciadv.abj6799)
  DOI : 10.1126/sciadv.abj6799
• Particle energization in colliding subcritical collisionless shocks investigated in the laboratory
  
  • Fazzini A.
  • Yao W.
  • Burdonov K.
  • Béard J.
  • Chen S. N.
  • Ciardi A.
  • d'Humières E.
  • Diab R.
  • Filippov E. D.
  • Kisyov S.
  • Lelasseux V.
  • Miceli M.
  • Moreno Q.
  • Orlando S.
  • Pikuz S.
  • Ribeyre X.
  • Starodubtsev M.
  • Zemskov R.
  • Fuchs J.
  Astronomy & Astrophysics - A&A, EDP Sciences, 2022, 665. Context. Colliding collisionless shocks appear across a broad variety of astrophysical phenomena and are thought to be possible sources of particle acceleration in the Universe. Aims: The main goal of our experimental and computational work is to understand the effect of the interpenetration between two subcritical collisionless shocks on particle energization. Methods: To investigate the detailed dynamics of this phenomenon, we performed a dedicated laboratory experiment. We generated two counter-streaming subcritical collisionless magnetized shocks by irradiating two Teflon (C<SUB>2</SUB>F<SUB>4</SUB>) targets with 100 J, 1 ns laser beams on the LULI2000 laser facility. The interaction region between the plasma flows was pre-filled with a low-density background hydrogen plasma and initialized with an externally applied homogeneous magnetic field perpendicular to the shocks. We also modeled the macroscopic evolution of the system via hydrodynamic simulations and the microphysics at play during the interaction via particle-in-cell (PIC) simulations. Results: Here, we report our measurements of the plasma density and temperature during the formation of the supercritical shocks, their transition to subcritical, and their final interpenetration. We find that in the presence of two shocks, the ambient ions reach energies around 1.5 times of those obtained with single shocks. Both the presence of the downstream zone of the second shock and of the downstream zone common for the two shocks play a role in the different energization: the characteristics of the perpendicular electric fields in the two areas indeed allow for certain particles to continue being accelerated or, at least, to avoid being decelerated. Conclusions: The findings of our laboratory investigation are relevant for our understanding of the energy distribution of high-energy particles that populate the interplanetary space in our solar system and the very local interstellar medium around the heliopause, where observations have indicated evidence of subcritical collisionless shocks that may eventually go on to collide with one another. (10.1051/0004-6361/202243277)
  DOI : 10.1051/0004-6361/202243277
• Roadmap toward a laser-plasma accelerator
  
  • Cros Brigitte
  • Delerue Nicolas
  • Bardon Matthieu
  • Beck Arnaud
  • Cassou Kevin
  • Corde Sébastien
  • Couprie Marie-Emmanuelle
  • Davoine Xavier
  • Dobosz-Dufrénoy Sandrine
  • Falcoz Franck
  • Faure Jérôme
  • Fuchs Julien
  • Hannachi Fazia
  • d'Humières Emmanuel
  • Kazamias Sophie
  • Lancia Livia
  • Leblanc Adrien
  • Lucas Bruno
  • Matthieu François
  • Massimo Francesco
  • Minenna Damien
  • Nghiem Phi
  • Pittman Moana
  • Simon Claire
  • Simon-Boisson Christophe
  • Specka Arnd
  • Sylla François
  • Tarisien Medhi
  • Thaury Cédric
  • Vincenti Henri
  • Flacco Alessandro
  , 2022.
• X-ray diffraction study of phase transformation dynamics of Fe and Fe-Si alloys along the shock Hugoniot using an x-ray free electron laser
  
  • Krygier A.
  • Harmand M.
  • Albertazzi B.
  • Mcbride E.
  • Miyanishi K.
  • Antonangeli Daniele
  • Inubushi Y.
  • Kodama R.
  • Koenig M.
  • Matsuoka T.
  • Mogni G.
  • Pietrucci F.
  • Saitta A.
  • Togashi T.
  • Umeda Y.
  • Vinci T.
  • Yabashi M.
  • Yabuuchi T.
  • Fiquet G.
  • Ozaki N.
  Physical Review B, American Physical Society, 2022, 105 (22), pp.L220102. The x-ray free electron laser (XFEL) enables probing highly compressed material response at the subnanosecond timescale. We exploit the ultrafast XFEL pulse to combine reflection x-ray diffraction and laserdriven shock compression to perform a study of phase transformation and stability in iron and Fe-Si alloys. Our approach enables us to observe that solid-solid phase transformations occur in iron and Fe-Si8.5wt% in ≤130 ps at ∼130 GPa; no transformation is observed in Fe-Si16wt% up to 110 GPa. Density Functional Theory calculations predict similar phase relations. (10.1103/PhysRevB.105.L220102)
  DOI : 10.1103/PhysRevB.105.L220102
• Nonlinear Compton scattering in time-dependent electric fields beyond the locally constant crossed field approximation
  
  • Gelfer E.G.
  • Fedotov A.M.
  • Mironov A.A.
  • Weber S.
  Physical Review D, American Physical Society, 2022, 106 (5), pp.056013. Locally constant crossed field approximation (LCFA) is a powerful tool for theoretical and numerical studies of various strong field quantum electrodynamical effects. We explore this approximation in detail for photon emission by a spinless particle in a strong time-dependent electric field. This kind of electromagnetic fields is of particular interest, because, in contrast to the comprehensively studied case of a plane wave, they are not crossed. We develop an approach for calculating photon emission probability in a generic time-dependent electric field, establish the range of applicability of LCFA, and calculate the corrections to it. (10.1103/PhysRevD.106.056013)
  DOI : 10.1103/PhysRevD.106.056013
• Minimally invasive surgery for neuroblastic tumours: A SIOPEN multicentre study: Proposal for guidelines
  
  • Gabra H.O.
  • Irtan S.
  • Cross K.
  • Lobos P.
  • Froeba-Pohl A.
  • Pio L.
  • Virgone C.
  • Guillén Burrieza G.
  • Gómez Chacón Villalba J.
  • Riccipetitoni G.
  • Guérin F.
  • Nightingale M.
  • Heloury Y.
  • Faraj S.
  • Leclair M.
  • Scalabre Aurélien
  • Mattioli G.
  • Warmann S.W.
  • Fuchs J.
  • Basta N.
  • Bjørnland K.
  • Matthyssens L.E.
  • Losty P.D.
  • Sarnacki S.
  European Journal of Surgical Oncology, WB Saunders - Elsevier, 2022, 48 (1), pp.283-291. (10.1016/j.ejso.2021.08.013)
  DOI : 10.1016/j.ejso.2021.08.013