Particle jets in colliding two ultraintense laser pulses of varying frequencies

Siddharth Tiwary,Naveen Kumar

doi:10.1103/physrevresearch.3.043190

Abstract

We present results on the evolution of jets (electrons-positrons and photons) formed in colliding two ultraintense laser pulses with varying frequencies and amplitudes. We focus on the nonlinear dynamics of the seeded electrons in the superposition of the two counterpropagating laser pulses and its implications for the experimentally measurable properties of jets, e.g., angular spectra and widths of the emitted jets, by changing the intensity and frequency of the two colliding laser pulses. We verify our analytical results by doing both Monte Carlo and two-dimensional particle-in-cell simulations.

Highlights

Generating and studying the dynamics of electron-positron (e-p) plasma in a laboratory setup are important for understanding several astrophysical objects such as pulsars, relativistic jets, and gamma-ray bursts (GRBs) where e-p plasmas are expected to be present, and for verifying the most important predictions made by quantum electrodynamics (QED) on the breakdown of a vacuum leading to the generation of e-p plasmas [1,2,3,4,5,6,7,8,9,10,11,12]
We have studied the nonlinear dynamics of a fermion and an electromagnetic cascade initiated by a fermion in the superposition of two counterpropagating laser pulses with different frequency or amplitude ratios
We demonstrate by Monte Carlo and PIC simulations that by tuning the frequency ratio of two laser pulses, one can control the directions of the particle jets that come out of the electromagnetic cascade

Summary

INTRODUCTION

Generating and studying the dynamics of electron-positron (e-p) plasma in a laboratory setup are important for understanding several astrophysical objects such as pulsars, relativistic jets, and gamma-ray bursts (GRBs) where e-p plasmas are expected to be present, and for verifying the most important predictions made by quantum electrodynamics (QED) on the breakdown of a vacuum leading to the generation of e-p plasmas [1,2,3,4,5,6,7,8,9,10,11,12]. The motion of the electron in a standing wave formed by two laser pulses is highly nonlinear, though it exhibits some attractor-type solutions that can be exploited to study the cascade formation in a laboratory setup. Do the ultrahigh-intensity laser pulses have broadband spectra, and the laser pulse frequency can change due to nonlinear plasma effects [25,38,39,40] This setup can be a natural setting for studying the cascade in counterpropagating optical laser pulses. The remainder of this paper is organized as follows: In Sec. II, we discuss the setup, followed by an analysis of the nonlinear dynamics of an electron in the standing wave created by two counterpropagating laser pulses of varying frequencies in Sec. III, where we derive the angle of emission of particles in the classical limit.

PHYSICAL SETUP

NONLINEAR DYNAMICS AND EXIT ANGLE OF PARTICLES

MONTE CARLO SIMULATIONS

COMPARISON WITH JETS FROM THE VACUUM DECAY

CONCLUSIONS