Target charging in short-pulse-laser-plasma experiments

• Published in: Physical review. E, Statistical, nonlinear, and soft matter physics Statistical, nonlinear, and soft matter physics, 2014-01, Vol.89 (1), p.013102-013102, Article 013102
• Main Authors: Dubois, J-L, Lubrano-Lavaderci, F, Raffestin, D, Ribolzi, J, Gazave, J, Compant La Fontaine, A, d'Humières, E, Hulin, S, Nicolaï, Ph, Poyé, A, Tikhonchuk, V T
• Format: Article
• Language: English
• Subjects: Computer Simulation; Electron Transport; Electrons; Lasers; Models, Chemical; Plasma Gases - chemistry; Plasma Gases - radiation effects
• ISSN: 1539-3755; 1550-2376
• DOI: 10.1103/physreve.89.013102

Interaction of high-intensity laser pulses with solid targets results in generation of large quantities of energetic electrons that are the origin of various effects such as intense x-ray emission, ion acceleration, and so on. Some of these electrons are escaping the target, leaving behind a significant positive electric charge and creating a strong electromagnetic pulse long after the end of the laser pulse. We propose here a detailed model of the target electric polarization induced by a short and intense laser pulse and an escaping electron bunch. A specially designed experiment provides direct measurements of the target polarization and the discharge current in the function of the laser energy, pulse duration, and target size. Large-scale numerical simulations describe the energetic electron generation and their emission from the target. The model, experiment, and numerical simulations demonstrate that the hot-electron ejection may continue long after the laser pulse ends, enhancing significantly the polarization charge.