Channeling of relativistic laser pulses in underdense plasmas and subsequent electron acceleration

N Naseri,V.Yu Bychenkov,K Popov,W Rozmus,D Pesme,P Mora,K A Tanaka,E Moses

doi:10.1051/epjconf/20135917001

Abstract

This contribution is concerned with the nonlinear behavior of a relativistic laser pulse focused in an underdense plasma and with the subsequent generation of fast electrons. Specifically, we study the interaction of laser pulses having their intensity Iλ2 in the range [1019, 1020] W/cm2 μm2, focused in a plasma of electron density n0 such that the ratio n0/nc lies in the interval [10−3, 2 × 10−2], nc denoting the critical density; the laser pulse power PL exceeds the critical power for laser channeling Pch. The laser-plasma interaction in such conditions is investigated by means of 3D Particle in Cell (PIC) simulations. It is observed that the laser front gives rise to the excitation of a surface wave which propagates along the sharp boundaries of the electron free channel created by the laser pulse. The mechanism responsible for the generation of the fast electrons observed in the PIC simulations is then analyzed by means of a test particles code. It is thus found that the fast electrons are generated by the combination of the betatron process and of the acceleration by the surface wave. The maximum electron energy observed in the simulations with Iλ2 = 1020 W/cm2 μm2 and n0/nc = 2 × 10−2 is 350 MeV.

Highlights

The interaction of high-energy laser pulses at relativistic intensities with underdense plasmas is an important area of research, for the studies of the fundamental aspects of the relativistic laser-plasma interaction physics, for its physical applications [1] in particle acceleration and in radiation sources, and for the fast ignition scenario [2] of the inertial confinement fusion
We study the interaction of laser pulses having their intensity I 2 in the range [1019, 1020] W/cm2 m2, focused in a plasma of electron density n0 such that the ratio n0/nc lies in the interval [10−3, 2 × 10−2], nc denoting the critical density; the laser pulse power PL exceeds the critical power for laser channeling Pch
It is observed that the laser front gives rise to the excitation of a surface wave which propagates along the sharp boundaries of the electron free channel created by the laser pulse

Summary

Introduction

The interaction of high-energy laser pulses at relativistic intensities with underdense plasmas is an important area of research, for the studies of the fundamental aspects of the relativistic laser-plasma interaction physics, for its physical applications [1] in particle acceleration and in radiation sources, and for the fast ignition scenario [2] of the inertial confinement fusion. The mechanism responsible for the generation of the fast electrons observed in the PIC simulations is analyzed by means of a test particles code.

Results

Conclusion