Abstracts

Oral presentations

Bruno Albertazzi, LULI, Ecole Polytechnique

Tutorial. Diagnostic of high-energy density plasma experiments

Laboratory experiments are essential tools to better understand High Energy Density (HED) phenomena and are complementary to theory and numerical simulations. However, the success of experimental campaign rely on the design and knowledge of the accessible parameters: What should we measure to answer the problem? What spatial, temporal, spectral resolution is needed? What precision is needed to be able to discriminate between different model?

In this tutorial talk, I will give an overview of the current HED diagnostics used on large-scale facilities and discuss their advantages and restrictions.

Konstantin Burdonov, LULI/LERMA, Sorbonne Université and Ecole Polytechnique

Review. Laboratory astrophysics investigations using laser-driven plasma in a strong magnetic field

The review is devoted to the experimental activities on study of various astrophysical phenomena, including the accretion phenomena and the magnetic reconnection processes, in the scaled laboratory experiment using laser-produced plasmas propagating in an externally applied magnetic field.

Alexis Casner, CEA, DAM, CESTA / Université de Bordeaux, CELIA

Review. Overview of laboratory astrophysics research opportunities on laser facilities

The High-Energy-Density (HED) regime refers to energy densities exceeding 10^11 J.m^-3 which cannot be achieved in the laboratory without external energy sources. Highly nonlinear hydrodynamics experiments in hot dense plasmas have benefited greatly from the advent of high-power lasers, such as Gekko XII in Japan [1], the National Ignition Facility (NIF) in the USA [2] or LMJ-PETAL in France [3]. In Inertial Confinement Fusion (ICF), a precise control of the development of instabilities at the ablation front was one of the key factors in the recent (almost) ignition breakthrough on NIF. Primarily built for ICF studies, the opportunities offered by high-power lasers to mimic astrophysical phenomena in the laboratory were recognized in the late 90’s [4]. The field of laboratory astrophysics is still a growing field of research, with experiments encompassing regimes relevant for young supernova remnants [5], as well as dynamo amplification of magnetic fields in subsonic, incompressible turbulent plasmas [6]. In contrary, the inefficiency of magnetic-field amplification in supersonic turbulent plasmas has been recently confirmed [3]. Besides self-generated magnetic field, capabilities are now available to impose 20-40 T external magnetic fields using Helmholtz-coils. Canonical hydrodynamics instabilities, such as Rayleigh-Taylor and Kelvin-Helmholtz instabilities, are currently benchmarked in highly magnetized environments [7] enabling progresses in MHD simulations of HED plasmas. To finish with, quantitative progresses in spatial and temporal resolution are enabled by novel x-ray diagnostics and novel capabilities. Among other, the emergence of HED stations on XFEL facilities offers another promising avenue to study turbulent HED plasmas. X-ray measurements were acquired on SACLA XFEL HED station, providing the first observations of a turbulent HED plasma with spatial resolution of several micrometers [8]. I will review the recent progresses in turbulent HED experiments worldwide [9].

A large fraction of the material of this review talk is based on various experiments performed in collaboration with colleagues from LULI, LLNL, OMEGA laboratories as well as Oxford and Chicago universities. They could not all be cited in this one-page abstract but their work will be fully acknowledged during the talk.

References

[1] T. Sano et al, Phys. Rev. E 104, 035206 (2021).

[2] A. Casner et al, Nuclear Fusion 59, 032002 (2019).

[3] A. Bott et al, arXiv preprint arXiv:2008.06594 (2020). Accepted in Phys. Rev. Letters.

[4] B.A.Remington, Rev. Mod. Phys. 78 (3), 755, 2006.

[5] G. Rigon et al, Phys. Rev. E 100, 021201(R) (2019).

[6] P. Tzeferacos et al, Nature Communications 9 (591), 2018.

[7] M. Manuel et al, Matter Radiat. Extremes 6, 026904 (2021).

[8] G. Rigon et al, Nature Comm. 12 (1), 2679 (2021).

[9] A. Casner, Philosophical Transaction Royal Society A: 379 (2189), 20200021 (2021).

Franck Delahaye, Observatoire de Paris

Review. Opacities for Astrophysics

The present debate on the reliability of the opacities for astrophysics, ignited initially by the solar convection zone problem, has reached the present climax with the new measurement of the Fe opacities on the Z-machine at the Sandia National Laboratory (Bailey et al. 2015). In order to understand the differences between all the theoretical results, on the one side, and experiments on the other as well as the differences between the different theoretical results, very detailed comparisons are needed. Many ingredients enter the calculation of opacities. Deconstructing the whole process and comparing the differences at each step should allow us to quantify the importance and impact of each of them on the final results.

Other contributing authors

Shinsuke Fujioka, ILE-Osaka, Japan, Tatiana Pikuz, ILE-Osaka, Japan, Jinyuan Dun, ILE-Osaka, Japan, Connor Ballance, Queen's Univ. Belfast UK, Nigel Badnell, Strathclyde Univ. Glasgow UK, Hanna Lamarre, LULI, Sebastien Lepape, LULI, Bruno Albertazzi, LULI, Michel Koenig, LULI, Christophe Blancard, CEA, Laurent Jacquet, CEA, Patrick Renaudin, CEA

Patrick Hennebelle, CEA

Tutorial. Collisionnal shocks and supersonic turbulence in the interstellar medium

The talk will start by reminding the basics of collisional shocks. Then it will present the topic of supersonic turbulence that is the relevant regime in the interstellar medium. Several cases will be considered including isothermal, two-phase and self-gravitating flows.

Martin Lemoine, IAP

Tutorial. Fermi acceleration at collisionless shock waves

Collisionless shock waves are natural offsprings of the powerful outflows launched by astrophysical eruptions or explosions, from solar flares to supernovae and even up to more extreme sources such as gamma-ray bursts. Those shock waves are generic sources of non-thermal radiation, which emanates from particles (in general, electrons) that have been accelerated at the shock. This tutorial aims at introducing the physics of this so-called Fermi acceleration process, from its most simple formulation, to a more modern (and more involved) description.

Thierry Passot, Observatoire de la Côte d'Azur

Review. Turbulence in the solar-terrestrial environment

We shall give a brief overview of selected current observations and theoretical challenges related to plasma turbulence in the solar-terrestrial environment. Particular attention will be paid to ion and electron scales, where magnetic reconnection plays a fundamental role and leads to a new regime, so-called reconnection-mediated turbulence. Another issue concerns imbalance in Alfvenic turbulence which is significant near the Sun and could affect the transition from MHD to sub-ionic scales. More compressible regimes encountered in the terretrial magnetosheath and associated with magnetosonic-like fluctuations, have larger cascade rates and may permit the development of micro-instabilities, e.g. of the mirror-type. The transition between the collisional and collisionless regimes is also a challenging issue for plasma modeling, that can be relevant both for the solar atmosphere and for the warm ionized phase of the interstellar medium.

Robin Piron, CEA

Tutorial. Introduction to atomic physics and EOS in dense plasmas

The need for microphysical properties in astrophysical applications covers both a wide range of plasma conditions, and a variety of properties (thermodynamic, radiative, transport). In this introductory presentation, we will explain the motivation for describing plasmas in terms of atoms and focus on the challenge such a modeling raises in the case of dense (i.e. non-ideal) plasmas. We will briefly review some models of atoms in a plasma, pinpoint the peculiarities of atomic processes in dense plasmas and point out some open problems relative to the calculation of certain atomic physics quantities in the case of dense plasmas.

Roch Smets. LPP

Review. Simulation tools in plasma physics and astrophysics

I will start the presentation by outlining the typical regime of plasmas encountered when they are produced by high power laser. Then, keeping in mind these range of application, I will present the different type of codes which can be used for plasma simulation, as well as their limitation of validity. I will then conclude the presentation by a discussion of recent simulations of laser plasma experiment.

François Soubiran, CEA DAM-DIF

Mandy Bethkenhagen, ENS Lyon

Review. EOS for planetary interiors: theoretical advances and experiments

With the advent of dedicated planet-hunting missions such as Kepler, TESS and soon PLATO, numerous exoplanets have been discovered challenging our conception of planetary systems. In particular, objects such as hot-Jupiters, mini-Neptunes or super-Earths, which were inconceivable thirty years ago, turned out to be rather common. The architectures of the observed planetary systems are also a challenge for formation and evolution theories. To model and comprehend these new worlds it is necessary to determine the properties of matter under extreme conditions with high accuracy. In that regard, ab initio simulations and high pressure static and dynamic experiments have proven to be extremely useful. In this presentation, we will discuss the capabilities of state-of-the-art ab initio simulations combined with cutting-edge experiments on exemplary materials. Along with astrophysical observations they continue to make valuable contributions in shaping new models for Solar System planets as well as for exoplanets. We will highlight the important role played by mixtures in planetary interiors and show how their equation of state and phase diagrams can be determined. Finally, we will review key physical properties of planetary interiors and discuss their influence on potential habitability.

Posters

Olga Alexandrova, LESIA, Observatoire de Paris

Kinetic turbulence spectrum between 0.3 and 1 AU

We investigate spectral properties of turbulence in the solar wind that is a weakly collisional astrophysical plasma, accessible to in-situ observations. Using the Helios search coil magnetometer measurements in the fast solar wind, in the inner heliosphere, we focus on properties of the turbulent magnetic fluctuations at scales smaller than the ion characteristic scales, the so-called kinetic plasma turbulence. At such small scales, we show that the magnetic power spectra between 0.3 and 0.9~AU from the Sun have a generic shape $\sim f^{-8/3}\exp{(-f/f_d)}$ where the dissipation frequency $f_d$ is correlated with the Doppler shifted frequency $f_{\rho e}$ of the electron Larmor radius. This behavior is statistically significant: all the observed kinetic spectra are well described by this model, with $f_d = f_{\rho e}/1.8$. Our results indicate that the electron gyroradius plays the role of the dissipation scale and marks the end of the electromagnetic cascade in the solar wind.

References

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.103.063202

Other contributing authors

Vamsee Krishna Jagarlamudi, Petr Hellinger, Milan Maksimovic, Andre Mangeney

A.S. Chuvatin, LPP (1)

A table-top experimental platform for study of space and astrophysical plasmas

We present an experimental program for production and study of plasmas of space and astrophysical interest. The plasmas are produced through joule heating and magnetic acceleration and they can be complementary to laser-produced plasma experiments for studying physical processes in space such as magnetic reconnection or particle acceleration (see for example Howes, PoP, 2018, Hare et al., PRL, 2017). The experimental device described here would allow plasma generation at centimetre space scale for shock physics, plasma jets, magnetic reconnection, plasma turbulence, etc. and to test theoretical models in different regimes (collisional, weakly collisional, magnetized or not) for a relatively modest operating cost.

Other contributing authors

A. Ciardi (2), O. Le Contel(1), J. Larour(1), A. Retinò(1), J.-F. Panis(2), F. Delahaye(2), R. Smets(1), P. Auvray(1), A. Boldarev (3), S. Pledel(1)

Affiliations

(1) Laboratoire de Physique des Plasmas, CNRS/Sorbonne Université/Université de Paris-Saclay/Observatoire de Paris/Ecole Polytechnique Institut Polytechnique de Paris, Campus Pierre et Marie Curie, Paris.

(2) Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères, CNRS/Observatoire de Paris/Sorbonne Université/Université de Cergy Paris, Campus Pierre et Marie Curie, Paris.

(3) M.V. Keldysh Institute of Applied Mathematics, Moscow, Russian Federation

Hanna Lahmar, LULI, LERMA

Experimental stellar opacity and simulations

Le Soleil est composé majoritairement de 73.5% d'hydrogène, de 24.8% d'hélium et de seulement moins de 2% en atome plus lourd (N. Grevesse and A. J. Sauval, Space Science Reviews, 1998). Cependant ces atomes lourds participent majoritairement à l'opacité de cet astre, à hauteur de 83% à l'opacité globale (~10% pour l'hydrogène, ~7% pour l'hélium, Bailey et al., Physic of Plasma, 2009). Et plus précisément, le fer, à lui seul, participe à près de 21% à cette opacité au niveau de la base de la zone de convection du Soleil. Une incertitude dans ce coefficient ϰ (l'opacité) a des effets très important dans la détermination de la structure du Soleil. Lors d'une mesure de l'opacité du fer dans les conditions solaires (Te~200eV, à la densité du solide), qui ont pu être atteintes grâce à la Z-machine (Sandia National Laboratory), de larges divergences entre les codes atomiques et les mesures ont pu être mises en évidence (Bailey, et al., Nature, 2015). Il y a donc une nécessité de nouvelles mesures d'opacité en utilisant une autre méthode pour atteindre ces conditions de hautes températures et de densité. C'est pourquoi on s'intéresse ici au chauffage par laser intense de cible typique (composé de l'élément d'intérêt) afin de pouvoir en mesurer l'opacité à terme. Ce travail est une étude préliminaire à de futurs expériences. Ces simulations, utilisant les caractéristiques du laser Apollon (CEA), ont pu montrer :

- le profil de température auquel on peut s'attendre dans l'élément de notre intérêt (ex : Fe, O, Ne, Al) qui a pu atteindre des températures de l'ordre de 100 eV,

- l'influence de la longueur typique de pré-plasma, créé du côté de l'arrivée du laser sur la cible, sur les profils de températures atteintes,

- le processus principal de chauffage qui est dû au chauffage ohmique.

Ces simulation, à l'aide du code PIC Smilei, ont été effectuées sur le HPC Irene du CEA.

Other contributing authors

Sébastien Le Pape, Franck Delahaye, Frédéric Pérez, Mickael Grech, Patrick Renaudin et Ludovic Lecherbourg

Virginia Bresci, Institut d' Astrophysique de Paris (IAP)

Saturation of the asymmetric current filamentation instability under conditions relevant to relativistic shock precursors

The current filamentation instability, which generically arises in the counterstreaming of supersonic plasma flows, is known for its ability to convert the free energy associated with anisotropic momentum distributions into kinetic-scale magnetic fields. The saturation of this instability has been extensively studied in symmetric configurations where the interpenetrating plasmas share the same properties (velocity, density, temperature). However, the most common configuration is that of asymmetric plasma flows, e.g. the precursor of relativistic collisionless shock waves in which a hot, dilute beam of accelerated particles reflected at the shock front encounter a cold, dense inflowing background plasma. To determine the appropriate criterion for saturation in this case, we have performed large-scale 2D particle-in-cell simulations of counterstreaming electron-positron pair and electron-ion plasmas. The results of this study allowed us to characterise which of the species determines saturation and by which mechanism, and which affects the properties of the instability, as the growth rate and the maximum wave number. Our results can be directly applied to the physics of relativistic, weakly magnetized shock waves, but they can also be generalized to other cases of study.

References

http://arxiv.org/abs/2111.04651

Other contributing authors

Laurent GREMILLET, CEA, Martin LEMOINE, IAP

Alexis Marret, LERMA, Sorbonne Université

The non-resonant streaming instability: from theory to experiment

The cosmic rays non-resonant streaming instability occurs when a population of super-Alfv\'enic ions propagates through an ambient plasma embedded in a magnetic field. The instability is believed to be the source of substantial magnetic field amplification and plays a crucial role, for example, in the acceleration of cosmic rays via the first order Fermi mechanism in supernova shocks. In this work we investigate numerically and analytically the effects of the background plasma temperature and particle collisions on the instability. We find that increasing the temperature of the ambient plasma can substantially reduce the growth rate and the magnitude of the saturated magnetic field. We also find that the non-resonant mode generates important pressure anisotropies, which retro-act on the instability and reduce its growth. Introducing Coulomb collisions between ions mitigates these anisotropies, favoring the growth of the unstable waves. In contrast, ion-neutral collisions have the expected effect of damping the instability. In addition to astrophysical applications, these results pave the way for the design of laboratory experiments on the non-resonant streaming instability.

References

Marret A., et al. "On the growth of the thermally modified non-resonant streaming instability", MNRAS, Volume 500, Issue 2, January 2021, Pages 2302–2315

Gabriel Perez-Callejo, Université de Bordeaux

Driving strongly magnetized HED plasmas at Omega

We present the design and first results of a novel all-optical platform to magnetize laser-driven cylindrical implosions at the OMEGA facility. The cylindrical targets are filled with Ar-doped D2 gas and are symmetrically imploded using a 36-beam 15 kJ, 1.5 ns laser drive. To investigate the effects of magnetization, the implosion was characterized using X-ray imaging and the Ar line emission was recorded with the XRS spectrometer. According to proton probing, the seed B-field generated with a pair of laser-driven coil (LDC) targets was <10 T, likely due to the large inductance of the coils. We simulated the platform with 2-D numerical simulations using the MHD codes FLASH and GORGON, which predict that a seed B-field with strength varied over the range 10 to 50 T is compressed to 8 to 30 kT, respectively. Such a compressed magnetic field is strong enough to alter the characteristic conditions of the compressed core. We show preliminary Ar spectra showing these changes in the hydrodynamic conditions, in agreement with the simulations. Additionally, we present a design to extend this platform to higher laser drives, such as those available at LMJ.

Other contributing authors

Mathieu BAILLY-GRANDVAUX, University of California San Diego, Ricardo FLORIDO, Universidad de Las Palmas de Gran Canaria, Chris A. WALSH, Lawrence Livermore National Laboratory, Marco GIGOSOS, Universidad de Valladolid, Farhat BEG, University of California San Diego, Christopher MCGUFFEY, General Atomics, Roberto C. MANCINI, University of Nevada Reno, Francisco SUZUKI-VIDAL, Imperial College London, Christos VLACHOS, Université de Bordeaux, João J. SANTOS, Université de Bordeaux

Victor Tranchant, LERMA/CEA

Laboratory experiments simulations of the interaction between X-ray bursts and neutron star's accretion disks.

Unstable fusion of accreted material onto the surface of a neutron star can lead to the sudden (few seconds) and intense (10^38 erg.s^-1) release of a X-flux called Type-I X-ray burst [1]. It is now generally accepted that this X-flux interacts with the optically thick surrounding accretion disk, implying modifications of its internal structure [2], and thus its observational properties [3]. During the burst, we state that a supersonic radiative wave [4] will break out and propagates through the medium. The internal structure of the disk being unreachable by means of direct observation, it becomes necessary to use numerical simulations to model the wave propagation. RAMSES-RT [5] simulations will then be presented. Observational difficulties make the direct comparison with simulations impossible, making it vital to find new means to confront these numerical results. Laboratory astrophysics experiments, using powerful laser facilities, can fill that void. By being able to create an intense X-flux in laboratory, it becomes possible to create an experiment equivalent to the astrophysical system. However, the usual scaling laws allowing to link the astrophysical and laboratory scales cannot be use in this case, as the radiative regimes at stake cannot be retrieve due to current technological limitations. Then, we will introduce a novel approach for laboratory astrophysics, based on Lie equivalence symmetries [6], allowing us to overcome the limitations established by similarity approach. We will conclude this poster by showing a new laboratory system equivalent to the astrophysical one, leading to a possible futur laser experiment.

References

[1] Galloway & Keek (2021) https://link.springer.com/chapter/10.1007/978-3-662-62110-3_5 or https://arxiv.org/abs/1712.06227#:~:text=Type%2DI%20X%2Dray%20bursts,progress%20over%20the%20preceding%20decade. (arxiv)

[2] Ballantyne & Everett (2005) https://iopscience.iop.org/article/10.1086/429860/meta

[3] Degenaar et al. (2018) https://link.springer.com/article/10.1007/s11214-017-0448-3

[4] Marshak (1958) https://aip.scitation.org/doi/abs/10.1063/1.1724332?casa_token=8QcTHUrKOVAAAAAA:g8yyPufdtNwwqVzkBA-22burUu5FIaFShLsbhahAISiq-B56R2jFEWJlXgJcTVy5nk2yzC4qKXg

[5] Rosdahl & Teyssier (2015) https://academic.oup.com/mnras/article/449/4/4380/1194692?login=true

[6] Lisle (1992) https://open.library.ubc.ca/soa/cIRcle/collections/ubctheses/831/items/1.0079820

Other contributing authors

Charpentier Nicolas, CEA, Van Box Som Lucile, CEA, Ciardi Andrea, LERMA, Falize Emeric, CEA,

Christos Vlachos University of Bordeaux

Laser-driven quasi-static B-fields for magnetized high energy-density experiments

The use of seed magnetic-fields (B-fields) in laser-driven compression experiments of pellet targets may lead, by advection in the in-flow plasma, to > 10kT B-fields across the compressed core. This constitutes a test bed for exploring extreme plasma magnetization phenomena. Such B-fields are indeed comparable to some of the highest observable in the Universe, and may reveal promising in a magneto-inertial fusion approach as they may be sufficient to confine fusion-ensued alpha-particles within the compressed hot spot. We designed such magnetized compression experiments in a cylindrical geometry, using seed B-fields between 5 and 50 T and for both 15 kJ and 300 kJ laser drive (respectively, for OMEGA and LMJ irradiation conditions). Our extended-MHD design shows in particular that the compressed B-field contains a significant proportion of the implosion energy and induce large electrical currents in the hot core plasma. One important challenge is to provide the needed enough strong seed B-fields. We explore laser interactions with coil-targets (CT) to produce them, in a geometry that gives easy access for diagnostics and do not produce a significant quantity of debris. At the LULI2000 facility we used ns laser pulses of ~1015 W/cm2 intensity (relevant for OMEGA or LMJ conditions) and reproducibly generated discharge currents of ~20 kA, yielding B-fields of ~50 T at the center of 500 µm-diameter coils. The fields were characterized using proton deflectometry at two perpendicular probing axes. Data confrontation with particle test simulations reveal features that can be distinctively linked to the looping current and with static charging of the wire surface. The characterized discharge currents are consistent with our predictions based on a plasma diode model which has been continuously improved and validated through benchmarking experiments over the past years.

Other contributing authors

C. Vlachos, V. Ospina-Bohorquez, M. Ehret, M. Lendrin, G. Pérez-Callejo, J.J. Santos, CELIA - University of Bordeaux, CNRS, CEA

P. Guillon, CELIA & Ecole Polytechnique, B. Albertazzi, M. Koenig - LULI, Ecole Polytechnique, S. Eitan – LULI & Ecole National Supérieure de Lyon, S. Malko - Princeton Plasma Physics Laboratory, X. Vaisseau, L. Gremillet – CEA, DAM, DIF, R. Fedosejevs, C. Kaur, M. Gjevre – University of Alberta, M. Bailly-Grandvaux - University of California, San Diego

Weipeng YAO, LULI - Sorbonne Université et Ecole Polytechnique

Stochastic ion acceleration by Magnetized Rayleigh-Taylor instability in colliding laser-produced plasma

Energetic charged particles, or cosmic rays, exist ubiquitously around the Universe. Fermi-type mechanisms are believed to be the source. Nevertheless, they need high-energy particles as seeds and this ``injection problem'' is still an open question. Here we report the observation of energetic particles above 1 MeV in the laboratory with the head-on collision of two laser-driven magnetized plasma plumes. Using three-dimensional magneto-hydrodynamic simulations with reactionless test particles, we propose a new stochastic acceleration mechanism that is closely associated with the magnetic Rayleigh-Taylor instability (MRTI) induced around the jet-collision region and is found to be consistent with the Weibull distribution. In addition, our simulation can well reproduce the experimental particle spectrum. Such efforts for astrophysically-relevant particle acceleration in the laboratory will certainly provide an alternative for the injection of particles from the thermal background into the Fermi-type mechanisms.

Other contributing authors

Julien GUYOT, Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-75005, Paris, France

Benjamin KHIAR, Office National d'Etudes et de Recherches Aérospatiales (ONERA), Palaiseau 91123, France

Tommaso VINCI, LULI - CNRS, CEA, UPMC Univ Paris 06 : Sorbonne Université, Ecole Polytechnique, Institut Polytechnique de Paris - F-91128 Palaiseau cedex, France

Guilhem REVET, LULI - CNRS, CEA, UPMC Univ Paris 06 : Sorbonne Université, Ecole Polytechnique, Institut Polytechnique de Paris - F-91128 Palaiseau cedex, France

Sophia CHEN, ELI-NP, ""Horia Hulubei"" National Institute for Physics and Nuclear Engineering, 30 Reactorului Street, RO-077125, Bucharest-Magurele, Romania

Konstantin BURDONOV, LULI - CNRS, CEA, UPMC Univ Paris 06 : Sorbonne Université, Ecole Polytechnique, Institut Polytechnique de Paris - F-91128 Palaiseau cedex, France

Eugene FILIPPOV, IAP, Russian Academy of Sciences, 603950, Nizhny Novgorod, Russia

Jerome BEARD, LNCMI, UPR 3228, CNRS-UGA-UPS-INSA, Toulouse 31400, France

Julien FUCHS, LULI - CNRS, CEA, UPMC Univ Paris 06 : Sorbonne Université, Ecole Polytechnique, Institut Polytechnique de Paris - F-91128 Palaiseau cedex, France

Andrea CIARDI, Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, F-75005, Paris, France