Backward-Propagating MeV Electrons in Ultra-Intense Laser Interactions: Standing Wave Acceleration and Coupling to the Reflected Laser Pulse

Abstract

Laser-accelerated electron beams have been created at a kHz repetition rate from the {\it reflection} of intense ($\sim 10^{18}$ W/cm${}^2$), $\sim$40 fs laser pulses focused on a continuous water-jet in an experiment at the Air Force Research Laboratory. This paper investigates Particle-in-Cell (PIC) simulations of the laser-target interaction to identify the physical mechanisms of electron acceleration in this experiment. We find that the standing-wave pattern created by the overlap of the incident and reflected laser is particularly important because this standing wave can "inject" electrons into the reflected laser pulse where the electrons are further accelerated. We identify two regimes of standing wave acceleration: a highly relativistic case ($a_0\ge 1$), and a moderately relativistic case ($a_0\sim 0.5$) which operates over a larger fraction of the laser period. In previous studies, other groups have investigated the highly relativistic case for its usefulness in launching electrons in the forward direction. We extend this by investigating electron acceleration in the {\it specular (back reflection) direction} and over a wide range of intensities ($10^{17}-10^{19}$ W cm${}^{-2}$).

arXiv commentNow includes experimental results and other additions, see also arXiv:1501.02261

References in corpus (4)

• Developments in laser-driven plasma accelerators
• Collimated electron jets by intense laser beam-plasma surface interaction under oblique incidence
• Prepulse and amplified spontaneous emission effects on the interaction of a petawatt class laser with thin solid targets
• A Novel Femtosecond-Gated, High-Resolution, Frequency-Shifted Shearing Interferometry Technique for Probing Pre-Plasma Expansion in Ultra-Intense Laser Experiments

Cited by in corpus (9)

• Kinetic and finite ion mass effects on the transition to relativistic self-induced transparency in laser-driven ion acceleration
• A Novel Femtosecond-Gated, High-Resolution, Frequency-Shifted Shearing Interferometry Technique for Probing Pre-Plasma Expansion in Ultra-Intense Laser Experiments
• Backward-propagating MeV electrons from $10^{18}$ W/cm${}^2$ laser interactions with water
• Dominance of hole-boring radiation pressure acceleration regime with thin ribbon of ionized solid hydrogen
• Optimizing Laser-Plasma Interactions for Ion Acceleration using Particle-in-Cell Simulations and Evolutionary Algorithms
• 3D PIC simulations of electron beams created via reflection of intense laser light from a water target
• Particle-in-Cell Simulations of Density Peak Formation and Ion Acceleration from Short Pulse Laser-Driven Ponderomotive Steepening
• Particle-in-Cell modeling of a potential demonstration experiment for double pulse enhanced target normal sheath acceleration
• Experimental observation and computational modeling of radial Weibel instability in high intensity laser-plasma interactions