Thesis title
Experiments and Modeling of Weakly Collisional Shocks in Laser-driven Plasmas
Composition of the jury
Mark Sherlock, Staff Scientist, Lawrence Livermore National Laboratory, reviewer
Alexis Casner, Research Director, CEA – Université de Bordeaux, reviewer
Anabella Araudo, Senior Scientist, Institute of Physics, Czech Academy of Sciences, examiner
Xavier Michaut, Professor, Sorbonne Université, examiner
Xavier Ribeyre, Research Director, CEA – Université de Bordeaux, examiner
Roch Smets, Professor, Sorbonne Université, PhD supervisor.
Andrea Ciardi, Professor, Sorbonne Université, PhD co-supervisor.
Anna Grassi, Associate Professor, Sorbonne Université, PhD co-supervisor (invited member).
Summary
Shock waves convert the kinetic energy of a flow into thermal energy, radiation, and energetic particles, both in astrophysical plasmas and in laser-driven laboratory experiments. This thesis investigates the weakly collisional regime, in which particle collisions and collective electromagnetic processes can act together to mediate this energy conversion and shape the shock structure.
Combining experiments at LULI2000 and Gekko XII with radiation-hydrodynamic and kinetic simulations, this work examines shock structure, heating, and mixing in laser-driven plasmas. A Bayesian analysis of time-resolved Thomson scattering measurements provides estimates of the temperatures and composition of interacting ion species. To our knowledge, these measurements provide one of the first experimental probes of the contact discontinuity between the piston and shocked ambient plasma in this regime.
The results reveal strong ion heating and extended mixing. While single-fluid simulations capture the global morphology of the interaction, these features require collisional kinetic simulations to be reproduced. This work provides a reference for exploring the transition between collisional and collisionless shocks.
Venue
Amphithéâtre Astier, Pierre et Marie Curie Campus, Sorbonne Université
4 place Jussieu, 75005 Paris
