Collisional effects on the electrostatic shock dynamics in thin-foil targets driven by an ultraintense short pulse laser
Journal article, 2020

We numerically investigate the impact of Coulomb collisions on the ion dynamics in high-Z, solid density caesium hydride and copper targets, irradiated by high-intensity (I~2×10^20 W/cm^2), ultrashort (~10 fs), circularly polarized laser pulses, using particle-in-cell simulations. Collisions significantly enhance electron heating, thereby strongly increasing the speed of a shock wave launched in the laser-plasma interaction. In the caesium hydride target, collisions between the two ion species heat the protons to ~100−1000 eV temperatures. However, in contrast to previous work (A E Turrell et al 2015 Nat. Commun. 6 8905), this process happens in the upstream only, due to nearly total proton reflection. This difference is ascribed to distinct models used to treat collisions in dense/cold plasmas. In the case of a copper target, ion reflection can start as a self-amplifying process, bootstrapping itself. Afterwards, collisions between the reflected and upstream ions heat these two populations significantly. When increasing the pulse duration to 60 fs, the shock front more clearly decouples from the laser piston, and so can be studied without direct interference from the laser. The shock wave formed at early times exhibits properties typical of both hydrodynamic and electrostatic shocks, including ion reflection. At late times, the shock is seen to evolve into a hydrodynamic blast wave.

laser plasma

collisions

electrostatic shocks

Author

Andréas Sundström

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

Laurent Gremillet

CEA DAM DIF

University Paris-Saclay

Evangelos Siminos

University of Gothenburg, Department of Physics

Istvan Pusztai

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

Plasma Physics and Controlled Fusion

0741-3335 (ISSN) 1361-6587 (eISSN)

Vol. 62 8 085015

Running away and radiating (PLASMA)

European Commission (EC), 2015-10-01 -- 2020-09-30.

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

Subject Categories

Fusion, Plasma and Space Physics

DOI

10.1088/1361-6587/ab9a62

More information

Latest update

9/15/2020