Injection dynamics of direct-laser accelerated electrons in a relativistic transparency regime

Abstract

The dynamics of electron injection in the direct laser acceleration (DLA) regime was investigated by means of three-dimensional particle-in-cell simulations and theoretical analysis. It is shown that when an ultra-intense laser pulse propagates into a near-critical density or relativistically transparent plasma, the longitudinal charge-separation electric field excites an ion wave. The ion wave modulates the local electric field and acts as a set of potential wells to guide the electrons, located on the edge of the plasma channel, to the central region, where the DLA takes place later on. In addition, it is pointed out that the self-generated azimuthal magnetic fields tend to suppress the injection process of electrons by deflecting them away from the laser field region. Understanding these physical processes paves the way for further optimizing the properties of direct-laser accelerated electron beams and the associated X/gamma-ray sources.

arXiv comment5 pages, 3 figures

References in corpus (6)

• Laser acceleration of ion bunches at the front surface of overdense plasmas
• Enhancement of electron energy to multi-GeV regime by a dual-stage laser-wakefield accelerator pumped by petawatt laser pulses
• Scalings for ultra-relativistic laser plasmas and monoenergetic electrons
• Generation of 'Super-Ponderomotive' Electrons due to a non-Wakefield interaction between a Laser Pulse and a Longitudinal Electric Field
• Microengineering laser plasma interactions at relativistic intensities
• Novel Aspects of Direct Laser Acceleration of Relativistic Electrons

Cited by in corpus (4)

• Scaling laws for direct laser acceleration in a radiation-reaction dominated regime
• Hybrid Stimulated Raman Scattering -- Two Plasmon Decay Instability and 3/2 Harmonic in Steep-Gradient Femtosecond Plasmas
• Magnetic field amplification to the gigagauss scale via dynamos driven by femtosecond lasers
• Direct laser acceleration: A model for the electron injection from the walls of a cylindrical guiding structure