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21 results on '"B. Khiar"'

1. Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field

Author

G. Revet, B. Khiar, E. Filippov, C. Argiroffi, J. Béard, R. Bonito, M. Cerchez, S. N. Chen, T. Gangolf, D. P. Higginson, A. Mignone, B. Olmi, M. Ouillé, S. N. Ryazantsev, I. Yu. Skobelev, M. I. Safronova, M. Starodubtsev, T. Vinci, O. Willi, S. Pikuz, S. Orlando, A. Ciardi, and J. Fuchs

Subjects
Science
Abstract

Mass outflow is a common process in astrophysical objects. Here the authors investigate in which conditions an astrophysically-scaled laser-produced plasma flow can be collimated and evolves in the presence of a misaligned external magnetic field.

Published
2021
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2. On the study of hydrodynamic instabilities in the presence of background magnetic fields in high-energy-density plasmas

Author

M. J.-E. Manuel, B. Khiar, G. Rigon, B. Albertazzi, S. R. Klein, F. Kroll, F. -E. Brack, T. Michel, P. Mabey, S. Pikuz, J. C. Williams, M. Koenig, A. Casner, and C. C. Kuranz

Subjects
Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Blast-wave-driven hydrodynamic instabilities are studied in the presence of a background B-field through experiments and simulations in the high-energy-density (HED) physics regime. In experiments conducted at the Laboratoire pour l’utilisation des lasers intenses (LULI), a laser-driven shock-tube platform was used to generate a hydrodynamically unstable interface with a prescribed sinusoidal surface perturbation, and short-pulse x-ray radiography was used to characterize the instability growth with and without a 10-T B-field. The LULI experiments were modeled in FLASH using resistive and ideal magnetohydrodynamics (MHD), and comparing the experiments and simulations suggests that the Spitzer model implemented in FLASH is necessary and sufficient for modeling these planar systems. These results suggest insufficient amplification of the seed B-field, due to resistive diffusion, to alter the hydrodynamic behavior. Although the ideal-MHD simulations did not represent the experiments accurately, they suggest that similar HED systems with dynamic plasma-β (=2μ0ρv2/B2) values of less than ∼100 can reduce the growth of blast-wave-driven Rayleigh–Taylor instabilities. These findings validate the resistive-MHD FLASH modeling that is being used to design future experiments for studying B-field effects in HED plasmas.

Published
2021
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3. X-ray spectroscopy evidence for plasma shell formation in experiments modeling accretion columns in young stars

Author

E. D. Filippov, I. Yu. Skobelev, G. Revet, S. N. Chen, B. Khiar, A. Ciardi, D. Khaghani, D. P. Higginson, S. A. Pikuz, and J. Fuchs

Subjects
Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Recent achievements in laboratory astrophysics experiments with high-power lasers have allowed progress in our understanding of the early stages of star formation. In particular, we have recently demonstrated the possibility of simulating in the laboratory the process of the accretion of matter on young stars [G. Revet et al., Sci. Adv. 3, e1700982 (2017)]. The present paper focuses on x-ray spectroscopy methods that allow us to investigate the complex plasma hydrodynamics involved in such experiments. We demonstrate that we can infer the formation of a plasma shell, surrounding the accretion column at the location of impact with the stellar surface, and thus resolve the present discrepancies between mass accretion rates derived from x-ray and optical-radiation astronomical observations originating from the same object. In our experiments, the accretion column is modeled by having a collimated narrow (1 mm diameter) plasma stream first propagate along the lines of a large-scale external magnetic field and then impact onto an obstacle, mimicking the high-density region of the stellar chromosphere. A combined approach using steady-state and quasi-stationary models was successfully applied to measure the parameters of the plasma all along its propagation, at the impact site, and in the structure surrounding the impact region. The formation of a hot plasma shell, surrounding the denser and colder core, formed by the incoming stream of matter is observed near the obstacle using x-ray spatially resolved spectroscopy.

Published
2019
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5. Biochar alleviates single and combined effects of salinity and drought stress in faba bean plants

Author

I. RAJHI, R. NEFISSI OUERTANI, N. FERCHICHI, B. KHIARI, L. EL-BASSI, and H. MHADHBI

Subjects
biochar, drought, faba bean, gas exchange, growth analysis, salinity, Botany, QK1-989
Abstract

This study aimed to evaluate the impact of four biochar concentrations (0, 2, 5, and 8%) on single and interactive effects of salinity and drought stresses on the morphological, physiological, and photosynthetic parameters of faba bean plants. PCA analysis showed that plants displayed different behavior under non-stressed and stressed conditions. The most discriminating quantitative characters were related to plant biomass production and photosynthesis, especially shoot dry mass, root dry mass, plant fresh mass, internal CO2 concentration, net CO2 assimilation rate, and relative water content. The obtained results confirm the biochar's important role in promoting plant growth under normal or stressed conditions. Thus, a better understanding of the impact of biochar on plant growth under drought and salinity stresses will be beneficial for sustainable agriculture.

Published
2024
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6. Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field

Author

Mirela Cerchez, Drew Higginson, E. D. Filippov, T. Gangolf, S. A. Pikuz, I. Yu. Skobelev, B. Khiar, G. Revet, Tommaso Vinci, B. Olmi, Salvatore Orlando, J. Béard, O. Willi, Rosaria Bonito, M. V. Starodubtsev, Costanza Argiroffi, M. Safronova, M. Ouillé, S. N. Ryazantsev, Julien Fuchs, Andrea Ciardi, Andrea Mignone, Sophia Chen, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institute of Applied Physics (IAP, Nizhny Novgorod), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Flash Center for Computational Science (FCCS), University of Chicago, Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Dipartimento di Fisica e Chimica [Palermo] (DiFC), Università degli studi di Palermo - University of Palermo, INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut für Laser und Plasmaphysik, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Horia Hulubei Natl Inst Phys & Nucl Engn IFIN HH, ELI NP Dept, Reactorului Str 30, Magurele 077125, Romania, Lawrence Livermore National Laboratory (LLNL), Dipartimento di Fisica Generale, Università di Torino, INAF - Osservatorio Astrofisico di Arcetri (OAA), The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) [Moscow, Russia], Revet G., Khiar B., Filippov E., Argiroffi C., Beard J., Bonito R., Cerchez M., Chen S.N., Gangolf T., Higginson D.P., Mignone A., Olmi B., Ouille M., Ryazantsev S.N., Skobelev I.Y., Safronova M.I., Starodubtsev M., Vinci T., Willi O., Pikuz S., Orlando S., Ciardi A., and Fuchs J.

Subjects
Science, Astrophysics::High Energy Astrophysical Phenomena, Nozzle, outflows, magnetohydrodynamics(MHD), shockwaves, astrophysical jets, General Physics and Astronomy, FOS: Physical sciences, Astrophysics, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Collimated light, Settore FIS/05 - Astronomia E Astrofisica, Ambient field, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Magnetic pressure, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Laboratory astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Jet (fluid), Multidisciplinary, Laser-produced plasmas, General Chemistry, Physics - Plasma Physics, Magnetic field, Plasma Physics (physics.plasm-ph), Astrophysics - Solar and Stellar Astrophysics, Physics::Accelerator Physics, Outflow, High Energy Physics::Experiment, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The shaping of astrophysical outflows into bright, dense, and collimated jets due to magnetic pressure is here investigated using laboratory experiments. Here we look at the impact on jet collimation of a misalignment between the outflow, as it stems from the source, and the magnetic field. For small misalignments, a magnetic nozzle forms and redirects the outflow in a collimated jet. For growing misalignments, this nozzle becomes increasingly asymmetric, disrupting jet formation. Our results thus suggest outflow/magnetic field misalignment to be a plausible key process regulating jet collimation in a variety of objects from our Sun’s outflows to extragalatic jets. Furthermore, they provide a possible interpretation for the observed structuring of astrophysical jets. Jet modulation could be interpreted as the signature of changes over time in the outflow/ambient field angle, and the change in the direction of the jet could be the signature of changes in the direction of the ambient field., Mass outflow is a common process in astrophysical objects. Here the authors investigate in which conditions an astrophysically-scaled laser-produced plasma flow can be collimated and evolves in the presence of a misaligned external magnetic field.

Published
2021
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7. Inefficient Magnetic-Field Amplification in Supersonic Laser-Plasma Turbulence

Author

A. F. A. Bott, Laura Chen, R. Rosch, Alexander Schekochihin, Gianluca Gregori, L. Le-Deroff, T. Caillaud, G. Boutoux, Donald Q. Lamb, A. Duval, Petros Tzeferacos, B. Khiar, B. Vauzour, I. Lantuéjoul, M. Koenig, Christopher Spindloe, Dongsu Ryu, Alexis Casner, B. Villette, Brian Reville, Department of Physics [Oxford], University of Oxford [Oxford], DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre d'études scientifiques et techniques d'Aquitaine (CESTA), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), KOENIG, Michel, University of Oxford, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
FOS: Physical sciences, General Physics and Astronomy, Magnetic Reynolds number, 01 natural sciences, [PHYS] Physics [physics], law.invention, Physics::Fluid Dynamics, law, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Supersonic speed, 010306 general physics, 010303 astronomy & astrophysics, [PHYS]Physics [physics], Physics, Magnetic energy, Turbulence, Plasma, Laser, Astrophysics - Astrophysics of Galaxies, Physics - Plasma Physics, Computational physics, Magnetic field, Plasma Physics (physics.plasm-ph), Cascade, Astrophysics of Galaxies (astro-ph.GA), Physics::Space Physics
Abstract

We report a laser-plasma experiment that was carried out at the LMJ-PETAL facility and realized the first magnetized, turbulent, supersonic plasma with a large magnetic Reynolds number ($\mathrm{Rm} \approx 45$) in the laboratory. Initial seed magnetic fields were amplified, but only moderately so, and did not become dynamically significant. A notable absence of magnetic energy at scales smaller than the outer scale of the turbulent cascade was also observed. Our results support the notion that moderately supersonic, low-magnetic-Prandtl-number plasma turbulence is inefficient at amplifying magnetic fields., 6 pages, 4 figures; supplemental information included (14 pages, 10 figures)

Published
2021
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8. Role of collisionality and radiative cooling in supersonic plasma jet collisions of different materials

Author

G. W. Collins, Gianluca Gregori, C.A. Speliotopoulos, Nicholas Aybar, B. Khiar, A. F. A. Bott, Petros Tzeferacos, Farhat Beg, F. Conti, and J. C. Valenzuela

Subjects
Physics, Shock (fluid dynamics), Radiative cooling, Mean free path, Turbulence, Plasma, Collisionality, 01 natural sciences, 010305 fluids & plasmas, Computational physics, 0103 physical sciences, Thermal, Supersonic speed, 010306 general physics
Abstract

Currently there is considerable interest in creating scalable laboratory plasmas to study the mechanisms behind the formation and evolution of astrophysical phenomena such as Herbig-Haro objects and supernova remnants. Laboratory-scaled experiments can provide a well diagnosed and repeatable supplement to direct observations of these extraterrestrial objects if they meet similarity criteria demonstrating that the same physics govern both systems. Here, we present a study on the role of collision and cooling rates on shock formation using colliding jets from opposed conical wire arrays on a compact pulsed-power driver. These diverse conditions were achieved by changing the wire material feeding the jets, since the ion-ion mean free path (λ_{mfp-ii}) and radiative cooling rates (P_{rad}) increase with atomic number. Low Z carbon flows produced smooth, temporally stable shocks. Weakly collisional, moderately cooled aluminum flows produced strong shocks that developed signs of thermal condensation instabilities and turbulence. Weakly collisional, strongly cooled copper flows collided to form thin shocks that developed inconsistently and fragmented. Effectively collisionless, strongly cooled tungsten flows interpenetrated, producing long axial density perturbations.

Published
2020
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9. X-ray spectroscopy evidence for plasma shell formation in experiments modeling accretion columns in young stars

Author

G. Revet, Sophia Chen, E. D. Filippov, B. Khiar, Drew Higginson, Andrea Ciardi, Julien Fuchs, D. Khaghani, I. Yu. Skobelev, S. A. Pikuz, Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)

Subjects
Physics, Nuclear and High Energy Physics, Star formation, Stellar atmosphere, Astrophysics, Plasma, 01 natural sciences, Atomic and Molecular Physics, and Optics, Accretion (astrophysics), [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], 010305 fluids & plasmas, Stars, Nuclear Energy and Engineering, 13. Climate action, 0103 physical sciences, lcsh:QC770-798, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Astrophysical plasma, Plasma diagnostics, Electrical and Electronic Engineering, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Chromosphere, Astrophysics::Galaxy Astrophysics
Abstract

Recent achievements in laboratory astrophysics experiments with high-power lasers have allowed progress in our understanding of the early stages of star formation. In particular, we have recently demonstrated the possibility of simulating in the laboratory the process of the accretion of matter on young stars [G. Revet et al., Sci. Adv. 3, e1700982 (2017)]. The present paper focuses on x-ray spectroscopy methods that allow us to investigate the complex plasma hydrodynamics involved in such experiments. We demonstrate that we can infer the formation of a plasma shell, surrounding the accretion column at the location of impact with the stellar surface, and thus resolve the present discrepancies between mass accretion rates derived from x-ray and optical-radiation astronomical observations originating from the same object. In our experiments, the accretion column is modeled by having a collimated narrow (1 mm diameter) plasma stream first propagate along the lines of a large-scale external magnetic field and then impact onto an obstacle, mimicking the high-density region of the stellar chromosphere. A combined approach using steady-state and quasi-stationary models was successfully applied to measure the parameters of the plasma all along its propagation, at the impact site, and in the structure surrounding the impact region. The formation of a hot plasma shell, surrounding the denser and colder core, formed by the incoming stream of matter is observed near the obstacle using x-ray spatially resolved spectroscopy.

Published
2019
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10. Fast electron transport dynamics and energy deposition in magnetized, imploded cylindrical plasma

Author

Mingsheng Wei, J. R. Davies, P. Forestier-Colleoni, Mathieu Bailly-Grandvaux, Shinsuke Fujioka, B. Khiar, J. J. Honrubia, C. McGuffey, J. J. Santos, P. Tzeferacos, Jonathan Peebles, Krish Bhutwala, Pierre-Alexandre Gourdain, Dimitri Batani, Daiki Kawahito, Kazuki Matsuo, Farhat Beg, C. M. Krauland, Stephanie Hansen, E. M. Campbell, S. Zhang, and Maylis Dozieres

Subjects
General Science & Technology, General Mathematics, General Physics and Astronomy, Implosion, Electron, 01 natural sciences, 010305 fluids & plasmas, Affordable and Clean Energy, 0103 physical sciences, fast electrons, Relativistic electron beam, 010306 general physics, Inertial confinement fusion, Physics, ICF, General Engineering, Articles, Plasma, Fusion power, compression, Magnetic field, Atomic physics, Joule heating, Research Article
Abstract

Inertial confinement fusion approaches involve the creation of high-energy-density states through compression. High gain scenarios may be enabled by the beneficial heating from fast electrons produced with an intense laser and by energy containment with a high-strength magnetic field. Here, we report experimental measurements from a configuration integrating a magnetized, imploded cylindrical plasma and intense laser-driven electrons as well as multi-stage simulations that show fast electrons transport pathways at different times during the implosion and quantify their energy deposition contribution. The experiment consisted of a CH foam cylinder, inside an external coaxial magnetic field of 5 T, that was imploded using 36 OMEGA laser beams. Two-dimensional (2D) hydrodynamic modelling predicts the CH density reaches 9.0 g cm − 3 , the temperature reaches 920 eV and the external B-field is amplified at maximum compression to 580 T. At pre-determined times during the compression, the intense OMEGA EP laser irradiated one end of the cylinder to accelerate relativistic electrons into the dense imploded plasma providing additional heating. The relativistic electron beam generation was simulated using a 2D particle-in-cell (PIC) code. Finally, three-dimensional hybrid-PIC simulations calculated the electron propagation and energy deposition inside the target and revealed the roles the compressed and self-generated B-fields play in transport. During a time window before the maximum compression time, the self-generated B-field on the compression front confines the injected electrons inside the target, increasing the temperature through Joule heating. For a stronger B-field seed of 20 T, the electrons are predicted to be guided into the compressed target and provide additional collisional heating. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

Published
2020
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11. Laser experiment for the study of accretion dynamics of Young Stellar Objects: design and scaling

Author

G. Revet, Andrea Ciardi, M. V. Starodubtsev, J. Béard, Salvatore Orlando, Rosaria Bonito, B. Khiar, Julien Fuchs, Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Istituto di Astrofisica Spaziale e Fisica cosmica - Palermo (IASF-Pa), Istituto Nazionale di Astrofisica (INAF), Institute of Applied Physics (IAP, Nizhny Novgorod), École normale supérieure - Paris (ENS-PSL), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, FRA, ROU, and RUS

Subjects
Nuclear and High Energy Physics, Young stellar object, FOS: Physical sciences, 01 natural sciences, 010305 fluids & plasmas, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, Adiabatic process, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Radiation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Plasma, Accretion (astrophysics), Physics - Plasma Physics, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Magnetic field, Computational physics, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Plasma Physics (physics.plasm-ph), Stars, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

A new experimental set-up designed to investigate the accretion dynamics in newly born stars is presented. It takes advantage of a magnetically collimated stream produced by coupling a laser-generated expanding plasma to a $2\times 10^{5}~{G}\ (20~{T})$ externally applied magnetic field. The stream is used as the accretion column and is launched onto an obstacle target that mimics the stellar surface. This setup has been used to investigate in details the accretion dynamics, as reported in [G. Revet et al., Science Advances 3, e1700982 (2017), arXiv:1708.02528}. Here, the characteristics of the stream are detailed and a link between the experimental plasma expansion and a 1D adiabatic expansion model is presented. Dimensionless numbers are also calculated in order to characterize the experimental flow and its closeness to the ideal MHD regime. We build a bridge between our experimental plasma dynamics and the one taking place in the Classical T Tauri Stars (CTTSs), and we find that our set-up is representative of a high plasma $\beta$ CTTS accretion case.

Published
2019
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12. Laser-Produced Magnetic-Rayleigh-Taylor Unstable Plasma Slabs in a 20 T Magnetic Field

Author

J. Béard, S. S. Makarov, Andrea Ciardi, Shihua Chen, Mirela Cerchez, E. D. Filippov, T. Gangolf, B. Khiar, G. Revet, S. A. Pikuz, Oswald Willi, M. Ouillé, A. A. Soloviev, Julien Fuchs, M. Safronova, K. F. Burdonov, M. V. Starodubtsev, I. Yu. Skobelev, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire National des Champs Magnétiques Pulsés (LNCMP), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institute of Applied Physics (IAP, Nizhny Novgorod), Institut für Laser und Plasmaphysik, Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], Joint Institute for High Temperatures of the RAS (JIHT), Russian Academy of Sciences [Moscow] (RAS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Lobachevsky State University [Nizhni Novgorod], Laboratoire national des champs magnétiques intenses - Toulouse (LNCMI-T), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), ANR-10-EQPX-0029,EQUIP@MESO,Equipement d'excellence de calcul intensif de Mesocentres coordonnés - Tremplin vers le calcul petaflopique et l'exascale(2010), ANR-11-LABX-0062,PLAS@PAR,PLASMAS à PARIS, au delà des frontières(2011), European Project: 787539,GENESIS - 10.3030/787539, and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Instability, Collimated light, law.invention, Physics::Fluid Dynamics, symbols.namesake, law, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Rayleigh scattering, 010306 general physics, Inertial confinement fusion, ComputingMilieux_MISCELLANEOUS, Physics, Condensed matter physics, Plasma, Laser, Physics - Plasma Physics, Magnetic field, Plasma Physics (physics.plasm-ph), Physics::Space Physics, Slab, symbols
Abstract

Magnetized laser-produced plasmas are central to many novel laboratory astrophysics and inertial confinement fusion studies, as well as in industrial applications. Here we provide the first complete description of the three-dimensional dynamics of a laser-driven plasma plume expanding in a 20 T transverse magnetic field. The plasma is collimated by the magnetic field into a slender, rapidly elongating slab, whose plasma-vacuum interface is unstable to the growth of the "classical", fluid-like magnetized Rayleigh-Taylor instability., Comment: Accepted for publication in Physical Review Letters

Published
2019
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13. The influence of the Hall term on the development of magnetized laser-produced plasma jets

Author

N. D. Hamlin, B. Khiar, Charles Seyler, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Physics, [PHYS]Physics [physics], Jet (fluid), Shock (fluid dynamics), Astrophysics::High Energy Astrophysical Phenomena, Rotational symmetry, Upwind scheme, Plasma, Mechanics, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Magnetic field, Physics::Plasma Physics, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Magnetohydrodynamics, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, Envelope (waves)
Abstract

We present 2D axisymmetric simulation results describing the influence of the Hall term on laser-produced plasma jets and their interaction with an applied magnetic field parallel to the laser axis. Bending of the poloidal B-field lines produces an MHD shock structure surrounding a conical cavity, and a jet is produced from the convergence of the shock envelope. Both the jet and the conical cavity underneath it are bound by fast MHD shocks. We compare the MHD results generated using the extended-MHD code Physics as an Extended-MHD Relaxation System with an Efficient Upwind Scheme (PERSEUS) with MHD results generated using GORGON and find reasonable agreement. We then present extended-MHD results generated using PERSEUS, which show that the Hall term has several effects on the plasma jet evolution. A hot low-density current-carrying layer of plasma develops just outside the plume, which results in a helical rather than a purely poloidal B-field, and reduces magnetic stresses, resulting in delayed flow conv...

Published
2018
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16. Time evolution of the electric field in a Hall thruster

Author

Julien Vaudolon, S. Mazouffre, and B. Khiar

Subjects
Physics, Distribution function, Physics::Plasma Physics, Temporal resolution, Electric field, Magnet, Field-emission electric propulsion, Analytical chemistry, Time evolution, Pulsed inductive thruster, Condensed Matter Physics, Computational physics, Coherence (physics)
Abstract

In order to characterize the natural oscillations of the electric field, the time-dependent Xe+ ion velocity distribution function is measured in the near-field plume of a low power permanent magnet Hall thruster. The distribution functions are obtained by means of a time-resolved laser-induced fluorescence technique based on a photon-counting method, while time coherence is ensured by applying a sinusoidal potential modulation on a floating electrode. The temporal resolution is 100 ns. The electric field profile is composed of two peaks. This peculiar shape is not yet understood. The electric field is shown to oscillate outside the thruster discharge channel. The results do not reveal the propagation of an ionization front.

Published
2014
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17. Dynamics of Nanosecond Laser Pulse Propagation and of Associated Instabilities in a Magnetized Underdense Plasma.

Author

Yao W, Higginson A, Marquès JR, Antici P, Béard J, Burdonov K, Borghesi M, Castan A, Ciardi A, Coleman B, Chen SN, d'Humières E, Gangolf T, Gremillet L, Khiar B, Lancia L, Loiseau P, Ribeyre X, Soloviev A, Starodubtsev M, Wang Q, and Fuchs J

Subjects
Heart Rate, Kinetics, Lasers, Electrons, Heating
Abstract

The propagation and energy coupling of intense laser beams in plasmas are critical issues in inertial confinement fusion. Applying magnetic fields to such a setup has been shown to enhance fuel confinement and heating. Here we report on experimental measurements demonstrating improved transmission and increased smoothing of a high-power laser beam propagating in a magnetized underdense plasma. We also measure enhanced backscattering, which our kinetic simulations show is due to magnetic confinement of hot electrons, thus leading to reduced target preheating.

Published
2023
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18. Inefficient Magnetic-Field Amplification in Supersonic Laser-Plasma Turbulence.

Author

Bott AFA, Chen L, Boutoux G, Caillaud T, Duval A, Koenig M, Khiar B, Lantuéjoul I, Le-Deroff L, Reville B, Rosch R, Ryu D, Spindloe C, Vauzour B, Villette B, Schekochihin AA, Lamb DQ, Tzeferacos P, Gregori G, and Casner A

Abstract

We report a laser-plasma experiment that was carried out at the LMJ-PETAL facility and realized the first magnetized, turbulent, supersonic (Ma_{turb}≈2.5) plasma with a large magnetic Reynolds number (Rm≈45) in the laboratory. Initial seed magnetic fields were amplified, but only moderately so, and did not become dynamically significant. A notable absence of magnetic energy at scales smaller than the outer scale of the turbulent cascade was also observed. Our results support the notion that moderately supersonic, low-magnetic-Prandtl-number plasma turbulence is inefficient at amplifying magnetic fields compared to its subsonic, incompressible counterpart.

Published
2021
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19. Role of collisionality and radiative cooling in supersonic plasma jet collisions of different materials.

Author

Collins GW, Valenzuela JC, Speliotopoulos CA, Aybar N, Conti F, Beg FN, Tzeferacos P, Khiar B, Bott AFA, and Gregori G

Abstract

Currently there is considerable interest in creating scalable laboratory plasmas to study the mechanisms behind the formation and evolution of astrophysical phenomena such as Herbig-Haro objects and supernova remnants. Laboratory-scaled experiments can provide a well diagnosed and repeatable supplement to direct observations of these extraterrestrial objects if they meet similarity criteria demonstrating that the same physics govern both systems. Here, we present a study on the role of collision and cooling rates on shock formation using colliding jets from opposed conical wire arrays on a compact pulsed-power driver. These diverse conditions were achieved by changing the wire material feeding the jets, since the ion-ion mean free path (λ_{mfp-ii}) and radiative cooling rates (P_{rad}) increase with atomic number. Low Z carbon flows produced smooth, temporally stable shocks. Weakly collisional, moderately cooled aluminum flows produced strong shocks that developed signs of thermal condensation instabilities and turbulence. Weakly collisional, strongly cooled copper flows collided to form thin shocks that developed inconsistently and fragmented. Effectively collisionless, strongly cooled tungsten flows interpenetrated, producing long axial density perturbations.

Published
2020
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20. Enhancement of Quasistationary Shocks and Heating via Temporal Staging in a Magnetized Laser-Plasma Jet.

Author

Higginson DP, Khiar B, Revet G, Béard J, Blecher M, Borghesi M, Burdonov K, Chen SN, Filippov E, Khaghani D, Naughton K, Pépin H, Pikuz S, Portugall O, Riconda C, Riquier R, Rodriguez R, Ryazantsev SN, Skobelev IY, Soloviev A, Starodubtsev M, Vinci T, Willi O, Ciardi A, and Fuchs J

Abstract

We investigate the formation of a laser-produced magnetized jet under conditions of a varying mass ejection rate and a varying divergence of the ejected plasma flow. This is done by irradiating a solid target placed in a 20 T magnetic field with, first, a collinear precursor laser pulse (10^{12}  W/cm^{2}) and, then, a main pulse (10^{13}  W/cm^{2}) arriving 9-19 ns later. Varying the time delay between the two pulses is found to control the divergence of the expanding plasma, which is shown to increase the strength of and heating in the conical shock that is responsible for jet collimation. These results show that plasma collimation due to shocks against a strong magnetic field can lead to stable, astrophysically relevant jets that are sustained over time scales 100 times the laser pulse duration (i.e., >70  ns), even in the case of strong variability at the source.

Published
2017
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21. Laboratory unraveling of matter accretion in young stars.

Author

Revet G, Chen SN, Bonito R, Khiar B, Filippov E, Argiroffi C, Higginson DP, Orlando S, Béard J, Blecher M, Borghesi M, Burdonov K, Khaghani D, Naughton K, Pépin H, Portugall O, Riquier R, Rodriguez R, Ryazantsev SN, Yu Skobelev I, Soloviev A, Willi O, Pikuz S, Ciardi A, and Fuchs J

Abstract

Accretion dynamics in the formation of young stars is still a matter of debate because of limitations in observations and modeling. Through scaled laboratory experiments of collimated plasma accretion onto a solid in the presence of a magnetic field, we open a first window on this phenomenon by tracking, with spatial and temporal resolution, the dynamics of the system and simultaneously measuring multiband emissions. We observe in these experiments that matter, upon impact, is ejected laterally from the solid surface and then refocused by the magnetic field toward the incoming stream. This ejected matter forms a plasma shell that envelops the shocked core, reducing escaped x-ray emission. This finding demonstrates one possible structure reconciling current discrepancies between mass accretion rates derived from x-ray and optical observations, respectively.

Published
2017
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