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Laser wakefield acceleration driven by few-cycle pulses on plasma mirrors (Conference Presentation)
Author(s): Neil Zaïm; Frederik Böhle; Maïmouna Bocoum; Aline Vernier; Stefan Haessler; Xavier Davoine; Laurent Videau; Jérôme Faure; Rodrigo López-Martens
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Paper Abstract

We study both experimentally and numerically the emission of energetic electrons during the reflection of a relativistic few-cycle laser pulse off a plasma mirror with controlled electron density gradient. A weak prepulse is used to trigger plasma expansion on a solid density target (optical grade fused silica) and electron emission is measured for different plasma scale lengths using a time-delayed relativistic-intensity few-cycle laser pulse with duration tunable from 24fs down to 3.5fs (1.5 cycle at the 719-nm carrier wave). Two distinct acceleration regimes are identified, for which the electron ejection mechanisms are radically different. On the one hand, when the plasma-vacuum interface is sharp, an attosecond electron bunch is emitted from the plasma at each laser optical cycle [1,2]. These electrons can then be efficiently accelerated in vacuum by the reflected laser field (vacuum laser acceleration or VLA) [3]. On the other hand, when the plasma scale length is larger, on the scale of a few laser wavelengths, a different regime is identified in which we observe what appears to be a collimated laser wakefield accelerated electron beam. Back-acceleration of energetic electrons can be explained by ionization injection of the rotating plasma waves inside the inhomogeneous electron density gradient formed at the plasma mirror surface [4]. These electrons are only detected when the laser pulse duration is shorter than 10 fs, clearly showing that new and unexpected laser-plasma interaction regimes become observable in the few-cycle regime. [1] M. Bocoum et al., Anti-correlated emission of high harmonics and fast electron beams from plasma mirrors, Physical Review Letters 116, 185001 (2016) [2] M. Thévenet et al., On the physics of electron ejection from laser-irradiated overdense plasmas, Physics of Plasmas 23, 063119 (2016) [3] M. Thévenet, et al. Vacuum laser acceleration of relativistic electrons using plasma mirror injectors, Nature Physics 12, 355–360 (2015) [4] N. Zaïm, et al. Laser wakefield acceleration driven by few-cycle laser pulses in overdense plasmas, manuscript in preparation

Paper Details

Date Published: 14 May 2019
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Proc. SPIE 11037, Laser Acceleration of Electrons, Protons, and Ions V, 110370E (14 May 2019); doi: 10.1117/12.2520802
Show Author Affiliations
Neil Zaïm, Ecole Nationale Supérieure de Techniques Avancées (France)
Frederik Böhle, Ecole Nationale Supérieure de Techniques Avancées (France)
Maïmouna Bocoum, Ecole Nationale Supérieure de Techniques Avancées (France)
Aline Vernier, Ecole Nationale Supérieure de Techniques Avancées (France)
Stefan Haessler, Ecole Nationale Supérieure de Techniques Avancées (France)
Xavier Davoine, CEA-DAM Ile-de-France (France)
Laurent Videau, CEA-DAM Ile-de-France (France)
Jérôme Faure, Ecole Nationale Supérieure de Techniques Avancées (France)
Rodrigo López-Martens, Lab. d'Optique Appliquée (France)


Published in SPIE Proceedings Vol. 11037:
Laser Acceleration of Electrons, Protons, and Ions V
Eric Esarey; Carl B. Schroeder; Jörg Schreiber, Editor(s)

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