Strong Shock generation by laser plasma interaction with or without laser smoothing in the context of shock ignition studies

PI: Dr. Sophie Baton, LULI, Palaiseau, France and Dr. Arnaud Colaitis, CELIA, Talence, France

Status: Performed in April 2018.


Preliminary results from the LMJ-PETAL experiment on hot electrons characterization in the context of shock ignition

S.D. Batona), A. Colaïtisb) et al,

a) LULI, CNRS-Ecole Polytechnique-CEA-Sorbonne Universités, F-91128 Palaiseau, France

b) CELIA, Université de Bordeaux-CNRS-CEA, F-33405 Talence, France

High Energy Density Physics 36 (2020) 100796

Keywords: Inertial confinement fusion, Shock ignition, Parametric instabilities, Hot electrons

Abstract : In the Shock Ignition scheme, the spike pulse intensity is well above the threshold of parametric instabilities, which produce a considerable amount of hot electrons that could be beneficial or detrimental to the ignition. To study their impact, an experiment has been carried out on the LMJ-PETAL facility with a goal to generate a strong shock inside a plastic layer under plasma conditions relevant to full-scale shock ignition targets. To evaluate the effect of hot electrons on the shock characteristics, laser temporal smoothing was either switched on or off, which in turns varies the quantity of hot electrons being generated. In this paper, we present preliminary results obtained during the experiment dedicated to the hot electron characterization. We present also calculations for the second part of the experiment, scheduled in 2020 and focused on the shock characterization.

Schematic drawing of the target (a).
Pulse shape of each of the three quads (b).
Simulation of Kα emission lines ratios Cu/Ag and Cu/Mo as a function of the electron temperature, assuming a single exponential electron energy distribution exp(-E/Thot). Experimental Kα ratios (full points) are compatible with a hot electron temperature Thot ≅ (10 ± 2) keV.