Publications

2022 | 2021 | 2020 | 2019

Below, by year, are the publications listed in the HAL open archive.

2025

High Gain Indirectly LED-Pumped Nd:Glass Lasers
- Nourry-Martin Maxime
- Fermon Nicolas
- Blanc Catherine Le
- Meignien Loïc
- Audebert Patrick
- Druon Frédéric
- Georges Patrick
- Balembois François
, 2025, pp.1-1. (10.1109/cleo/europe-eqec65582.2025.11110210)
DOI : 10.1109/cleo/europe-eqec65582.2025.11110210
Study of the Fast Dynamics of Optical Aberrations on Nd:Glass Flash-Pumped Kilojoule-Class Laser Chains Toward the Coherent Beam Combining
- Lebegue Pierre
- Rapeneau Cyril
- Badarau Doina
- Froidevaux Marie
- de Sousa Joanna
- Meignien Loïc
- Doudet Ivan
- Chan Nolan
- Wattellier Benoit
- Audebert Patrick
- Papadopoulos Dimitris
- Druon Frédéric
, 2025, pp.1-1. (10.1109/cleo/europe-eqec65582.2025.11111358)
DOI : 10.1109/cleo/europe-eqec65582.2025.11111358
Generation of Temporally Incoherent and Arbitrarily Shaped Optical Pulses Using Semiconductor Optical Amplifier for Fusion Applications
- Meignien Loïc
- Delagnes Jean-Christophe
- Hanna Marc
- Lebegue Pierre
- Froidevaux Marie
- Papadopoulos Dimitris
- Druon Frédéric
- Audebert Patrick
, 2025. (10.1109/cleo/europe-eqec65582.2025.11109840)
DOI : 10.1109/cleo/europe-eqec65582.2025.11109840
Incoherent Diffraction Imaging with Pseudo-Thermal Light Sources
- Biesterfeld Peer
- San Miguel Claveria Pablo
- Antunes Sebastiao
- Fernandes Matilde
- Garcia Matilde
- Nunes Matilde
- Ansia Fernandez Lucas
- O. Williams Gareth
- Frohlich Sven
- Theidel David
- Mosel Philip
- Fsaifes Ihsan
- Trabattoni Andrea
- Piccardo Marco
- Chanteloup Jean-Christophe
- Kovacev Milutin
- Merdji Hamed
- Fajardo Marta
, 2025, pp.37. This paper introduces a low-cost, table-top setup for studying Incoherent Diffraction Imaging (IDI)—a technique that extracts a target's structure from second-order spatial intensity correlations (g⁽²⁾) rather than coherent light, making it suitable for incoherent sources like laser-plasma X-rays. Instead of using large Free Electron Laser facilities, the authors built a Pseudo-Thermal Light Source from a CW diode laser (660 nm) illuminating a rotating ground-glass diffuser, allowing them to tune spatial and temporal coherence and successfully measure g⁽²⁾ correlations that matched simulations. This versatile platform lets them benchmark IDI's scaling behavior (Signal-to-Background and Signal-to-Noise ratios) and assess its potential for nanometer-scale imaging before moving to large X-ray facilities. (10.1109/CLEO/Europe-EQEC65582.2025.11111547)
DOI : 10.1109/CLEO/Europe-EQEC65582.2025.11111547
Numerical modeling of isochoric heating experiments using the Troll code in the warm dense matter regime
- Rassou Sébastien
- Bonneau Marie
- Rousseaux Christophe
- Vaisseau Xavier
- Cayzac Witold
- Denoeud Adrien
- Perez Frédéric
- Beaumont Tom
- Demoulins Morris
- Pain Jean‐christophe
Contributions to Plasma Physics, Wiley-VCH Verlag, 2025, 65 (8-9). Experiments of isochoric heating by protons of solid material were recently performed at LULI laser facilities. In these experiments, protons, produced from target normal sheath acceleration (TNSA) of Au foil with the PICO2000 laser, deposit their energy into an aluminum or copper foil initially at room temperature and solid density. The heated material reaches the warm dense matter regime with temperature in the rear face of the material between 1 and 5 eV. The temperature is inferred by streaked optical pyrometry and the proton beam is characterized by Thomson parabola. The high‐energy protons produced by TNSA are modeled to deduce the initial proton distribution before the slowing down in the target. Hydrodynamic radiative simulations were next performed using the Troll code in multidimensional geometry. In the Troll code, the heating of protons is modeled with a Monte Carlo transport module of charged particles and the calculation of the energy deposited by the protons in the matter is performed using stopping power formulas like Srim functions. The results of simulations with the Troll code are compared with the experimental results. An acceptable agreement between experiment and simulation is found for the temperature at the rear of the material using Sesame equation of state and Srim stopping power for protons in aluminum. (10.1002/ctpp.70030)
DOI : 10.1002/ctpp.70030
The structure of liquid carbon elucidated by in situ X-ray diffraction
- Kraus Dominik
- Rips Johannes
- Schörner Maximilian
- Vorberger Jan
- Ranjan Divyanshu
- Lütgert Julian
- Heuser Benjamin
- Eggert Jon H.
- Liermann Hanns-Peter
- Oleynik Ivan I.
- Pandolfi Silvia
- Redmer Ronald
- Sollier Arnaud
- Strohm Cornelius
- Volz Travis J.
- Albertazzi Bruno
- Ali Suzanne Jihad
- Antonelli Luca
- Bähtz Carsten
- Ball Orianna B.
- Banerjee Saumyabrata
- Belonoshko A. B.
- Bolme C. A.
- Bouffetier V.
- Briggs R.
- Buakor K.
- Butcher T.
- Cerantola V.
- Chantel Julien
- Coleman A. L.
- Collier J.
- Collins G. W.
- Comley A. J.
- Cowan T. E.
- Cristoforetti G.
- Cynn H.
- Descamps A.
- Di Cicco A.
- Di Dio Cafiso S.
- Dorchies F.
- Duff M. J.
- Dwivedi A.
- Edwards C.
- Errandonea D.
- Galitskiy S.
- Galtier E.
- Ginestet Helene
- Gizzi L.
- Gleason A.
- Göde S.
- Gonzalez J. M.
- Gorman M. G.
- M. Harmand
- Hartley N. J.
- Heighway P. G.
- Hernandez-Gomez C.
- Higginbotham A.
- Höppner H.
- Husband R. J.
- Hutchinson T. M.
- Hwang H.
- Keen D. A.
- Kim J.
- Koester P.
- Konôpková Z.
- Krygier A.
- Labate L.
- Laso Garcia A.
- Lazicki A. E.
- Lee Y.
- Mason P.
- Masruri M.
- Massani B.
- Mcbride E. E.
- Mchardy J. D.
- Mcgonegle D.
- Mcguire C.
- Mcwilliams R. S.
- Merkel Sébastien
- Morard G.
- Nagler B.
- Nakatsutsumi M.
- Nguyen-Cong K.
- Norton A.-M.
- Ozaki N.
- Otzen C.
- Peake D. J.
- Pelka A.
- Pereira K. A.
- Phillips J. P.
- Prescher C.
- Preston T. R.
- Randolph L.
- Ravasio A.
- Santamaria-Perez D.
- Savage D. J.
- Schölmerich M.
- Schwinkendorf J.-P.
- Singh S.
- Smith J.
- Smith R. F.
- Spear J.
- Spindloe C.
- Suer T.-A.
- Tang M.
- Toncian M.
- Toncian T.
- Tracy S. J.
- Trapananti A.
- Vennari C. E.
- Vinci T.
- Tyldesley M.
- Vogel S. C.
- Walsh J. P. S.
- Wark J. S.
- Willman J. T.
- Wollenweber L.
- Zastrau U.
- Brambrink E.
- Appel K.
- Mcmahon M. I.
Nature, Nature Publishing Group, 2025, 642 (8067), pp.351–355. Carbon has a central role in biology and organic chemistry, and its solid allotropes provide the basis of much of our modern technology1. However, the liquid form of carbon remains nearly uncharted2, and the structure of liquid carbon and most of its physical properties are essentially unknown3. But liquid carbon is relevant for modelling planetary interiors4,5 and the atmospheres of white dwarfs6, as an intermediate state for the synthesis of advanced carbon materials7,8, inertial confinement fusion implosions9, hypervelocity impact events on carbon materials10 and our general understanding of structured fluids at extreme conditions11. Here we present a precise structure measurement of liquid carbon at pressures of around 1 million atmospheres obtained by in situ X-ray diffraction at an X-ray free-electron laser. Our results show a complex fluid with transient bonding and approximately four nearest neighbours on average, in agreement with quantum molecular dynamics simulations. The obtained data substantiate the understanding of the liquid state of one of the most abundant elements in the universe and can test models of the melting line. The demonstrated experimental abilities open the path to performing similar studies of the structure of liquids composed of light elements at extreme conditions. (10.1038/s41586-025-09035-6)
DOI : 10.1038/s41586-025-09035-6
Zeeman splitting observations in laser-produced magnetized blast waves
- Triantafyllidis A.
- Marquès J.-R.
- Ferri S.
- Calisti A.
- Benkadoum Y.
- de León Y.
- Dearling A.
- Ciardi A.
- Béard J.
- Lagarrigue J.-M.
- Ozaki N.
- Koenig M.
- Albertazzi B.
Matter and Radiation at Extremes, AIP Publishing, 2025, 10 (4). We report the observation of Zeeman splitting in multiple spectral lines emitted by a laser-produced, magnetized plasma (1–3 × 1018 cm−3, 1–15 eV) in the context of a laboratory astrophysics experiment under a controlled magnetic field up to 20 T. Nitrogen lines (NII) in the visible range (563–574 nm) were used to diagnose the magnetic field and plasma conditions. This was performed by coupling our data with the Stark–Zeeman line-shape code PPPB. The excellent agreement between experiment and simulations paves the way for a non-intrusive experimental platform to get time-resolved measurements of the local magnetic field in laboratory plasmas. (10.1063/5.0256859)
DOI : 10.1063/5.0256859
Laser driven FLASH radiobiology using a high dose and ultra high dose rate single pulse proton source
- Flacco A
- Bayart E.
- Romagnani L
- Cavallone M.
- de Marzi L.
- Fouillade C
- Giaccaglia C.
- Heinrich S.
- Lamarre-Jouenne I.
- Monzac J.
- Parodi K.
- Patriarca A
- Rösch T
- Schreiber J
- Tischendorf L
Scientific Reports, Nature Publishing Group, 2025, 15, pp.16511. Laser-driven proton sources have long been developed with an eye on their potential for medical application to radiation therapy. These sources are compact, versatile, and show peculiar characteristics such as extreme instantaneous dose rates, short duration and broad energy spectrum. Typical temporal modality of laser-driven irradiation, the so-called fast-fractionation, results from the composition of multiple, temporally separated, ultra-short dose fractions. In this paper we present the use of a high-energy laser system for delivering the target dose in a single nanosecond pulse, for ultra-fast irradiation of biological samples. A transport line composed by two permanent-magnet quadrupoles and a scattering system is used to improve the dose profile and to control the delivered dose-per-pulse. A single-shot dosimetry protocol for the broad-spectrum proton source using Monte Carlo simulations was developed. Doses as high as 20 Gy could be delivered in a single shot, lasting less than 10 ns over a 1 cm diameter biological sample, at a dose-rate exceeding 10 9 Gy s -1 . Exploratory application of extreme laser-driven irradiation conditions, falling within the FLASH irradiation protocol, are presented for irradiation in vitro and in vivo. A reduction of radiation-induced oxidative stress in vitro and radiation-induced developmental damage compatible with the onset of FLASH effect were observed in vivo, whereas anti-tumoral efficacy was confirmed by cell survival assay. (10.1038/s41598-025-01105-z)
DOI : 10.1038/s41598-025-01105-z
Electron-electron collisions in calculations of the electrical conductivity for warm dense matter based on density functional theory
- Röpke G.
- Redmer R.
- Schörner Max
- Reinholz Heidi
- Kleinschmidt Uwe
- Bethkenhagen M.
Physical Review E, American Physical Society (APS), 2025, 111 (5), pp.055201. Density-functional-theory-based molecular dynamics simulations (DFT-MD) are a very successful tool to calculate the electrical conductivity of materials in the region of warm and dense matter. However, it requires a correction to implement the contribution of electron-electron collisions in the low-density, high-temperature region of plasmas. Based on the virial expansion of the electrical conductivity, a correction factor is presented, motivated by generalized linear response theory. To obtain accurate results for conductivity, the exact second virial coefficient is required, and a benchmark for high temperatures is given. For different materials, we identify the region in the temperature-density plane where the contribution of electron-electron collisions to the electrical conductivity is essential. We present new data of DFT-MD simulation of the electrical conductivity of Be for extreme conditions and show the validity of the virial expansion. (10.1103/PhysRevE.111.055201)
DOI : 10.1103/PhysRevE.111.055201
Model-free Rayleigh weight from x-ray Thomson scattering measurements
- Dornheim T.
- Bellenbaum H.
- Bethkenhagen M.
- Hansen S.
- Böhme M.
- Döppner T.
- Fletcher L.
- Gawne T.
- Gericke D.
- Hamel S.
- Kraus D.
- Macdonald M.
- Moldabekov Zh.
- Preston T.
- Redmer R.
- Schörner M.
- Schwalbe S.
- Tolias P.
- Vorberger J.
Physics of Plasmas, American Institute of Physics, 2025, 32 (5), pp.052712. X-ray Thomson scattering (XRTS) has emerged as a powerful tool for the diagnostics of matter under extreme conditions. In principle, it gives one access to important system parameters such as the temperature, density, and ionization state, but the interpretation of the measured XRTS intensity usually relies on theoretical models and approximations. In this context, a key property is given by the Rayleigh weight that describes the electronic localization around the ions. Here, we show that it is possible to extract the Rayleigh weight directly from the experimental data without the need for any model calculations or simulations. As a practical application, we consider an experimental measurement of strongly compressed Be at the National Ignition Facility [Döppner et al., Nature 618, 270–275 (2023)]. We demonstrate that experimental results for the Rayleigh weight open up new avenues for the interpretation of XRTS experiments by matching the measurement with ab initio simulations such as density functional theory or path integral Monte Carlo. Interestingly, this new procedure leads to significantly lower density compared to previously used chemical models. (10.1063/5.0238630)
DOI : 10.1063/5.0238630
Ion acoustic instability resulting from suprathermal electrons generated by stimulated Raman scattering in laser-plasma interactions
- Rousseaux C.
- Baton S. D.
- Glize K.
- Lancia L.
- Bénisti D.
- Sary G.
- Gremillet L.
Physical Review Letters, American Physical Society, 2025, 134 (16), pp.165102. Using space-time-resolved Thomson scattering, we investigate experimentally the development of electrostatic waves in a preformed undercritical helium plasma driven by a 1.059 μm laser pulse of ∼1.5 ps duration and ∼10$^{15-16}$ W cm$^{-2}$ mean intensity. We observe the excitation of intense ion plasma waves (IAWs) over a broad wave number range, distinct from what is expected from stimulated Brillouin scattering or Langmuir decay instability. These IAWs are correlated with the occurrence of backward stimulated Raman scattering (B-SRS) at earlier times but persist much longer than the B-SRS-driven electron plasma waves. Particle-in-cell modeling reveals that they result from an ion acoustic instability triggered by the bulk electrons drifting against the ions to neutralize the current carried by the B-SRS-generated hot electrons. The properties of the simulated unstable IAWs match well with the measurements (10.1103/PhysRevLett.134.165102)
DOI : 10.1103/PhysRevLett.134.165102
Femtosecond temperature measurements of laser-shocked copper deduced from the intensity of the x-ray thermal diffuse scattering
- Wark Justin S.
- Peake D. J.
- Stevens T.
- Heighway P. G.
- Ping Y.
- Sterne P.
- Albertazzi B.
- Ali S. J.
- Antonelli L.
- Armstrong M. R.
- Baehtz C.
- Ball O. B.
- Banerjee S.
- Belonoshko A. B.
- Bolme C. A.
- Bouffetier V.
- Briggs R.
- Buakor K.
- Butcher T.
- Di Dio Cafiso S.
- Cerantola V.
- Chantel Julien
- Di Cicco A.
- Coleman A. L.
- Collier J.
- Collins G.
- Comley A. J.
- Coppari F.
- Cowan T. E.
- Cristoforetti G.
- Cynn H.
- Descamps A.
- Dorchies F.
- Duff M. J.
- Dwivedi A.
- Edwards C.
- Eggert J. H.
- Errandonea D.
- Fiquet G.
- Galtier E.
- Laso Garcia A.
- Ginestet Helene
- Gizzi L.
- Gleason A.
- Goede S.
- Gonzalez J. M.
- Gorman M. G.
- Harmand M.
- Hartley N.
- Hernandez-Gomez C.
- Higginbotham A.
- Höppner H.
- Humphries O. S.
- Husband R. J.
- Hutchinson T. M.
- Hwang H.
- Keen D. A.
- Kim J.
- Koester P.
- Konopkova Z.
- Kraus D.
- Krygier A.
- Labate L.
- Lazicki A. E.
- Lee Y.
- Liermann H.-P.
- Mason P.
- Masruri M.
- Massani B.
- Mcbride E. E.
- Mcguire C.
- Mchardy J. D.
- Mcgonegle D.
- Mcwilliams R. S.
- Merkel Sébastien
- Morard G.
- Nagler B.
- Nakatsutsumi M.
- Nguyen-Cong K.
- Norton A.-M.
- Oleynik I. I.
- Otzen C.
- Ozaki N.
- Pandolfi S.
- Pelka A.
- Pereira K. A.
- Phillips J. P.
- Prescher C.
- Preston T. R.
- Randolph L.
- Ranjan D.
- Ravasio A.
- Redmer R.
- Rips J.
- Santamaria-Perez D.
- Savage D. J.
- Schoelmerich M.
- Schwinkendorf J.-P.
- Singh S.
- Smith J.
- Smith R. F.
- Sollier A.
- Spear J.
- Spindloe C.
- Stevenson M.
- Strohm C.
- Suer T.-A.
- Tang M.
- Toncian M.
- Toncian T.
- Tracy S. J.
- Trapananti A.
- Tschentscher T.
- Tyldesley M.
- Vennari C. E.
- Vinci T.
- Vogel S. C.
- Volz T. J.
- Vorberger J.
- Willman J. T.
- Wollenweber L.
- Zastrau U.
- Brambrink E.
- Appel K.
- Mcmahon M. I.
Journal of Applied Physics, American Institute of Physics, 2025, 137 (15), pp.155904. We present 50-fs, single-shot measurements of the x-ray thermal diffuse scattering (TDS) from copper foils that have been shocked via nanosecond laser ablation up to pressures above ∼135 GPa. We hence deduce the x-ray Debye–Waller factor, providing a temperature measurement. The targets were laser-shocked with the DiPOLE 100-X laser at the High Energy Density endstation of the European X-ray Free-Electron Laser. Single x-ray pulses, with a photon energy of 18 keV, were scattered from the samples and recorded on Varex detectors. Despite the targets being highly textured (as evinced by large variations in the elastic scattering) and with such texture changing upon compression, the absolute intensity of the azimuthally averaged inelastic TDS between the Bragg peaks is largely insensitive to these changes, and allowing for both Compton scattering and the low-level scattering from a sacrificial ablator layer provides a reliable measurement of T/ΘD2, where ΘD is the Debye temperature. We compare our results with the predictions of the SESAME 3336 and LEOS 290 equations of state for copper and find good agreement within experimental errors. We, thus, demonstrate that single-shot temperature measurements of dynamically compressed materials can be made via thermal diffuse scattering of XFEL radiation. (10.1063/5.0256844)
DOI : 10.1063/5.0256844
Nouveau dispositif Pistil dédié à la métrologie de surfaces d'onde segmentées pour les lasers à combinaison cohérente
- Rousseaux Thomas
, 2025. Afin de réaliser des lasers pouvant délivrer des puissances crête et moyenne élevées, de nouvelles stratégies ont émergé depuis quelques dizaines d’années, reposant sur l’utilisation combinée de nombreuses fibres laser pré-amplifiées pour générer un faisceau recombiné ultra intense. Pour garantir son efficacité, il est nécessaire de contrôler parfaitement la phase de chacune des fibres. Dans ce contexte, l’interférométrie Pistil a été développée à l’ONERA, offrant un outil de métrologie, contrôle et diagnostic des sources laser CBC. La technique repose sur l’utilisation d’un masque à trous et d’un réseau de diffraction afin d’analyser, à travers des interférogrammes, les différences de phase entre toutes les fibres voisines du système laser. Durant cette thèse, une nouvelle version de l’interféromètre a été développée, délaissant le masque à trous au profit d’une matrice de microlentilles. Cette innovation permet de prendre en compte l’intégralité de la surface d'onde incidente et rend le dispositif plus compact et facile à mettre en œuvre. Ce manuscrit propose une description théorique et une modélisation détaillée de ce nouvel instrument, nommé FullPistil. Il a ensuite été testé sur un banc expérimental développé pour simuler une surface d’onde segmentée grâce à un miroir segmenté, ce qui a permis de vérifier l’algorithme de reconstruction et révélé une fidélité de métrologie en dessous de λ/160. Enfin, le prototype a été intégré sur une chaîne laser CBC afin d’évaluer ses performances en conditions réelles et identifier les améliorations possibles. L’interféromètre est promis à une utilisation multiple sur une chaîne laser CBC, en boucle fermée comme en boucle ouverte, de l’aide à l’alignement au diagnostic laser, en passant par la mesure rapide pour le contrôle-commande. (10.70675/1c12a882zc831z4450z8615z2ca834ef1028)
DOI : 10.70675/1c12a882zc831z4450z8615z2ca834ef1028
Characterization and performance of the Apollon main short-pulse laser beam following its commissioning at 2 PW level
- Yao Weipeng
- Lelièvre Ronan
- Cohen Itamar
- Waltenspiel Tessa
- Allaoua Amokrane
- Antici Patrizio
- Ayoul Yohann
- Beck Arie
- Beluze Audrey
- Blancard Christophe
- Cavanna Daniel
- Chabanis Mélanie
- Chen Sophia N
- Cohen Erez
- Cossé Philippe
- Ducasse Quentin
- Dumergue Mathieu
- Hai Fouad El
- Evrard Christophe
- Filippov Evgeny
- Freneaux Antoine
- Gautier Donald Cort
- Gobert Fabrice
- Goupille Franck
- Grech Mickael
- Gremillet Laurent
- Heller Yoav
- d'Humières Emmanuel
- Lahmar Hanna
- Lancia Livia
- Lebas Nathalie
- Lecherbourg Ludovic
- Marchand Stéphane
- Mataja Damien
- Meyniel Gabriel
- Michaeli David
- Papadopoulos Dimitris
- Perez Frédéric
- Pikuz Sergey
- Pomerantz Ishay
- Renaudin Patrick
- Romagnani Lorenzo
- Trompier François
- Veuillot Edouard
- Vinchon Thibaut
- Mathieu François
- Fuchs Julien
Physics of Plasmas, American Institute of Physics, 2025, 32 (4), pp.043106. We present the results of the second commissioning phase of the short-focal-length area of the Apollon laser facility, located in Saclay, France. This phase was conducted using the main laser beam (F1), scaled to a peak power of 2 PetaWatts. Under the tested conditions, the F1 beam delivered on-target pulses with a maximum energy of up to 45 J and a duration of 22 fs. Several diagnostics were deployed to assess the facilitys performance. Key measurements included the on-target focal spot and its spatial stability, along with characterizations of secondary sources generated by irradiating solid targets. These evaluations aim at assisting users in designing future experiments. The laser-target interactions were thoroughly characterized, with emissions of energetic ions, X-rays, and neutrons recorded, demonstrating good laser-to-target coupling efficiency. Additionally, we successfully demonstrated the simultaneous operation of the F1 beam with the auxiliary 0.5 PW F2 beam of Apollon, enabling dual-beam operation. This commissioning phase paves the way for the next stage in 2025, which will involve scaling the F1 beam to 8 PW, progressing towards the ultimate goal of achieving 10 PW power. (10.1063/5.0252874)
DOI : 10.1063/5.0252874
Generic method to assess transmutation feasibility for nuclear waste treatment and application to irradiated graphite
- Rasson Mathieu
- Fuchs Julien
- Augé Grégoire
- Quéri Jean-Louis
- Laurent Gérard
, 2023, pp.109675. Graphite-moderated nuclear reactors have already produced more than 250000 tons of irradiated nuclear graphite, or i-graphite, world-wide. The sustainability of this technology relies on the end-of-life management of its moderator, which is activated into a long-lived nuclear waste, by neutron fluxes, during operating time. In particular, C14 is created. Nuclear transmutation, enabled by laser-driven particle acceleration, has been envisioned as a potential novel treatment scheme for long-lived nuclear waste. By triggering controlled nuclear reactions with energetic particles, long-lived radionuclides could be transformed into stable isotopes. Such a system could treat the C14 nuclei trapped within the i-graphite matrix, which is difficult to isolate by other means. This work performs a quantitative preliminary study of this transmutation scheme, in order to assess its feasibility at an industrial scale. The method used can be transposed to assess any transmutation scheme using a beam of particles directly sent on the material to be treated. First, a nuclear interaction channel which transmutes C14 nuclei without creating new long-lived radionuclides is identified. It consists in the choice of a type of particle, among which protons, gamma photons and neutrons can all be accelerated by laser-matter interaction; and it is completed by the adequate energy at which this particle must be sent on i-graphite. To that end, the nuclear cross-sections of C12, C13 and C14 are reviewed, neglecting other impurities in i-graphite. Then, based on the interaction channel identification, the energy cost of this scheme is estimated. Protons between 1 and 5 MeV make it possible to transmute C14 without creating any new long-lived activity. However, our result show that, even in this favorable reaction channel, the transmutation energy cost is too high for an i-graphite transmutation scheme to be feasible. (10.1016/j.anucene.2022.109675)
DOI : 10.1016/j.anucene.2022.109675
Modelling Thomson scattering in a hydrogen plasma at stellar interior conditions using the hypernetted‐chain approach
- Schumacher Samuel
- Lütgert Julian
- Gericke Dirk O
- Bethkenhagen Mandy
- Döppner Tilo
- Landen Otto L
- Shaffer Nathaniel R
- Starrett Charles E
- Kraus Dominik
Contributions to Plasma Physics, Wiley-VCH Verlag, 2025, 65, pp.e70002. Under the extreme conditions found in small stars, where electron degeneracy and Coulomb coupling are significant, accurate modeling of Thomson scattering is crucial for determining opacity, a primary quantity for stellar energy transport. We use hypernetted‐chain calculations, incorporating quantum pseudopotentials and electron‐exchange effects to obtain the electron–electron static structure factor to calculate the Thomson scattering transport cross‐section for conditions prevailing in the interior of small stars. These results are compared to those from average‐atom simulations and analytical calculations. Our findings support laboratory astrophysics experiments aimed at benchmarking opacity models for stellar interiors, particularly for red dwarf stars, and help to bridge theoretical models with observations. (10.1002/ctpp.70002)
DOI : 10.1002/ctpp.70002
Étude expérimentale et théorique des opacités stellaires
- Lahmar Hanna
, 2025. The opacity of a plasma plays a key role in its evolution, and its effects are considerable in the fields of inertial confinement fusion and astrophysics.In particular, opacity affects the structure of stars.The context of this thesis is the Sun's interior, and in particular the boundary between the convective zone (CZ) and the radiative zone (RZ), determined by the star's opacity.Theoretical models of the Sun's structure, based on its composition of various atoms and their opacities, show a notable disagreement with helioseismological observations: the theoretical position of the ZC/ZR boundary differs from measurements.One possible explanation is that the contribution of heavy elements (Ne, O and Fe) to opacity has been underestimated.During this thesis, experiments were carried out on the LULI 2000 and Apollon laser facilities to measure iron opacity under conditions relevant to the solar context.Isochoric heating of a solid target by ultra-high intensity laser (UHI) enabled temperatures between 30 and 1600 eV to be reached, while maintaining a density close to that of the solid.Kinetic simulations of the laser-plasma interaction were carried out to understand the heating process of a solid material and assess the conditions that can be reached.Unprecedented transmission spectra for aluminum and iron were obtained.Although some of the results remain unclear and require further study, these findings mark the first steps in the development of an opacity measurement platform using UHI lasers. (10.70675/2c9f6a05z0a0cz4ddbz8040z6645ccf72160)
DOI : 10.70675/2c9f6a05z0a0cz4ddbz8040z6645ccf72160
Experimental and Numerical Studies of the Collapse of Dense Clouds Induced by Herbig–Haro Stellar Jets
- Fontaine Marin
- Busschaert Clotilde
- Benkadoum Yaniss
- Bertrix Isabeau
- Koenig Michel
- Lefèvre Frédéric
- Marquès Jean-Raphaël
- Oportus Diego
- Ikeda Akihiko
- Matsuda Yasuhiro
- Falize Émeric
- Albertazzi Bruno
The Astrophysical Journal, American Astronomical Society, 2025, 981 (2), pp.172. Abstract This study investigates the influence of Herbig–Haro jets on initiating star formation in dense environments. When molecular clouds are nearing gravitational instability, the impact of a protostellar jet could provide the impetus needed to catalyze star formation. A high-energy-density experiment was carried out at the LULI2000 laser facility, where a supersonic jet generated by a nanosecond laser was used to compress a foam or plastic ball, mimicking the interaction of a Herbig–Haro jet with a molecular cloud. Simulations using the 3D radiation hydrodynamics code TROLL provided comprehensive data for analyzing ball compression and calculating jet characteristics. After applying scaling laws, similarities between stellar and experimental jets were explored. Diagnostic simulations—including density gradient, emission, and X-ray radiographies—showed strong agreement with experimental data. The results of the experiment, supported by simulations, demonstrate that the impact of a protostellar jet on a molecular cloud could reduce the Bonnor–Ebert mass by approximately 9%, thereby initiating collapse. (10.3847/1538-4357/adb715)
DOI : 10.3847/1538-4357/adb715
Experimental and numerical studies of the collapse of dense clouds induced by Herbig–Haro stellar jets
- Fontaine Marin
- Busschaert Clotilde
- Benkadoum Yaniss
- Bertrix Isabeau
- Koenig Michel
- Lefèvre Frédéric
- Marquès Jean-Raphaël
- Oportus Diego
- Ikeda Akihiko
- Matsuda Yasuhiro
- Falize Émeric
- Albertazzi Bruno
The Astrophysical Journal, American Astronomical Society, 2025, 981 (2), pp.172. This study investigates the influence of Herbig–Haro jets on initiating star formation in dense environments. When molecular clouds are nearing gravitational instability, the impact of a protostellar jet could provide the impetus needed to catalyze star formation. A high-energy-density experiment was carried out at the LULI2000 laser facility, where a supersonic jet generated by a nanosecond laser was used to compress a foam or plastic ball, mimicking the interaction of a Herbig–Haro jet with a molecular cloud. Simulations using the 3D radiation hydrodynamics code TROLL provided comprehensive data for analyzing ball compression and calculating jet characteristics. After applying scaling laws, similarities between stellar and experimental jets were explored. Diagnostic simulations—including density gradient, emission, and X-ray radiographies—showed strong agreement with experimental data. The results of the experiment, supported by simulations, demonstrate that the impact of a protostellar jet on a molecular cloud could reduce the Bonnor–Ebert mass by approximately 9%, thereby initiating collapse. (10.3847/1538-4357/adb715)
DOI : 10.3847/1538-4357/adb715
Coherent combining of large-aperture high-energy Nd:glass laser amplifiers
- Lebegue Pierre
- de Sousa Joanna
- Rapenau Cyril
- Badarau Doina
- Andrieu Jordan
- Audebert Patrick
- Druon Frédéric
- Papadopoulos Dimitrios
High Power Laser Science and Engineering, Cambridge University Press, 2025, 13, pp.e4. We present coherent beam combining of nanosecond pulses with 20-J energy and large beams using a Sagnac interferometer geometry based on Nd:glass rod-type amplifiers. In this study, we demonstrate that coherent beam combining is compatible with large-diameter energetic beams, presenting, therefore, an interesting and solid perspective towards the performance improvement of large-scale laser facilities, especially in terms of high-repetition-rate and high-energy operation. We demonstrate that for energy of 20 J, the coherent combination efficiency is around 92%, with high beam quality and long-term stability. A thorough temporal and spatial characterization of the system’s operation is provided to forecast the various potentialities available for large-scale facilities. (10.1017/hpl.2024.84)
DOI : 10.1017/hpl.2024.84
Improvement of the spatial quality of high energy lasers at high-repetition rate : development of stimulated Brillouin scattering phase conjugate mirrors for the correction of wavefront aberrations
- Humblot Raphaël
, 2025. High-energy lasers are important tools in a large variety of scientific and industrial domains such as plasma physics, machining or energy sources for secondary lasers. Currently, the main drawback of such systems is their low repetition rate, limiting the number of shots provided. This limit rises from thermal energy accumulation shot after shot inside the amplifiers of the lasers systems during operation, generating laser beam wavefront distortion up to complete laser dysfunction. In this thesis, a collaboration between Amplitude laser, an industrial laser manufacturer, Laboratoire Charles Fabry, and Laboratoire pour l'Utilisation des Lasers Intenses (LULI), aim to develop a component capable of correcting those wavefront distortions. This component, called phase conjugated mirrors, uses a nonlinear effect called stimulated Brillouin scattering to invert the wavefront and allow self-correction of the laser wavefront aberration in a double pass amplifying scheme. In this work, the existing theoretical framework of the nonlinear effect is used for the development of numerical models simulating the reflection. Those models are applied to the design of experimental phase conjugate mirrors whose properties are investigated. The thesis places an emphasis on the fidelity of the mirror, that is to say, its capacity to conserve the spatial and temporal pulse properties while properly inverting the wavefront. In particular, the optical configuration used, and the input laser parameters are shown to have a large influence on the reflection quality. The capacity to be applied to arbitrary temporal shapes is demonstrated for the first time and paves the way to the usage of phase conjugate mirrors for broader applications requiring unusual temporal shapes. The phase conjugate mirror stability and reliability are considered for the usage in industrial commercial laser systems and no particular erratic behaviour is identified. The limits of the components are investigated up to unprecedented input energy and wavefront aberrations levels making this component compatible for laser sources up to the kilojoule energy level. (10.70675/4d8a3aeaza64dz4a38z9220z1722466a676f)
DOI : 10.70675/4d8a3aeaza64dz4a38z9220z1722466a676f
Indirectly LED-pumped Nd:glass: potential for high energy laser facilities
- Nourry-Martin Maxime
- Fermon Nicolas
- Le Blanc Catherine
- Meignien Loïc
- Audebert Patrick
- Druon Frédéric
- Georges Patrick
- Balembois François
Optica, Optical Society of America - OSA Publishing, 2025, 12 (3), pp.311. <div>Flashlamp-pumped<p>Nd:glass is used as a power amplifier in many high energy laser facilities. Despite the problems of this old technology, flashlamps are still being considered for the next generation of lasers as diode laser pumping is far from being ready. This work presents an alternative for pumping high energy lasers: LEDs combined with luminescence concentrators. Using a pump head consisting of a green-yellow Ce:LuAG luminescent concentrator pumped by 2240 LEDs, we demonstrate a Nd:glass laser oscillator producing 25 mJ at 1053 nm for an absorbed pump energy of 138 mJ. The small signal gain reaches 1.25 in a single pass despite the short length of the Nd:glass rod (20 mm). These results reveal the potential of indirect LED pumping for Nd:glass amplifiers in high energy lasers.</p></div> (10.1364/OPTICA.533492)
DOI : 10.1364/OPTICA.533492
Dynamics and energy dissipation of collisional blast waves in a perpendicular magnetic field
- Triantafyllidis A.
- Marquès J.-R.
- Benkadoum Y.
- de León Y.
- Ciardi A.
- Béard J.
- Lagarrigue Jean-Marc
- Ozaki N.
- Koenig M.
- Dearling A.
- Albertazzi B.
Physics of Plasmas, American Institute of Physics, 2025, 32 (2). We experimentally investigate the evolution and dynamics of laser-produced collisional blast waves (BW) under the influence of a perpendicular magnetic field up to 20 T. We show that an external magnetic field causes the BW to diverge from the Taylor–Sedov solution while also impacting its structural morphology. We notably explore the significance of various magnetohydrodynamic (MHD) processes occurring on scales similar to the width of the BW front by comparing their characteristic lengths to it and demonstrate that the downstream plasma's transition from being super- to sub-magnetosonic plays a pivotal role in the overall structure. Our results show that multiple MHD effects can contribute to shaping a magnetized BW, illustrating the complexity of the underlying physics. (10.1063/5.0238064)
DOI : 10.1063/5.0238064
Dynamics and energy dissipation of collisional blast waves in a perpendicular magnetic field
- Triantafyllidis A.
- Marquès J.-R.
- Benkadoum Y.
- de León Y.
- Ciardi A.
- Béard J.
- Lagarrigue J.-M.
- Dearling A.
- Ozaki N.
- Koenig M.
- Albertazzi Bruno
Physics of Plasmas, American Institute of Physics, 2025, 32 (2). We experimentally investigate the evolution and dynamics of laser-produced collisional blast waves (BW) under the influence of a perpendicular magnetic field up to 20 T. We show that an external magnetic field causes the BW to diverge from the Taylor–Sedov solution while also impacting its structural morphology. We notably explore the significance of various magnetohydrodynamic (MHD) processes occurring on scales similar to the width of the BW front by comparing their characteristic lengths to it and demonstrate that the downstream plasma's transition from being super- to sub-magnetosonic plays a pivotal role in the overall structure. Our results show that multiple MHD effects can contribute to shaping a magnetized BW, illustrating the complexity of the underlying physics. (10.1063/5.0238064)
DOI : 10.1063/5.0238064
Compton photons at the GeV scale from self-aligned collisions with a plasma mirror
- Matheron Aimé
- Marquès Jean-Raphaël
- Lelasseux Vincent
- Shou Yinren
- Andriyash Igor A
- Phung Vanessa Ling Jen
- Ayoul Yohann
- Beluze Audrey
- Dăncuş Ioan
- Dorchies Fabien
- d'Souza Flanish
- Dumergue Mathieu
- Frotin Mickaël
- Gautier Julien
- Gobert Fabrice
- Gugiu Marius
- Krishnamurthy Santhosh
- Kargapolov Ivan
- Kroupp Eyal
- Lancia Livia
- Lazăr Alexandru
- Leblanc Adrien
- Lo Mohamed
- Mataja Damien
- Mathieu François
- Papadopoulos Dimitrios
- Claveria Pablo San Miguel
- Phuoc Kim Ta
- Talposi Anda-Maria
- Tata Sheroy
- Ur Călin A
- Ursescu Daniel
- Văsescu Lidia
- Doria Domenico
- Malka Victor
- Ghenuche Petru
- Corde Sebastien
, 2025. With today's multi-petawatt lasers, testing quantum electrodynamics (QED) in the strong field regime, where the electric field exceeds the Schwinger critical field in the rest frame of an electron, becomes within reach. Inverse Compton scattering of an intense laser pulse off a high-energy electron beam is the mainstream approach, resulting in the emission of high-energy photons that can decay into Breit-Wheeler electron-positron pairs. Here, we demonstrate experimentally that very high energy photons can be generated in a self-aligned single-laser Compton scattering setup, combining a laser-plasma accelerator and a plasma mirror. Reaching up to the GeV scale, photon emission via nonlinear Compton scattering exhibits a nonclassical scaling in the experiment that is consistent with electric fields reaching up to a fraction $\chi\simeq0.3$ of the Schwinger field in the electron rest frame. These foolproof collisions guaranteed by automatic laser-electron overlap provide a new approach for precise investigations of strong-field QED processes.

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