Relativistic Laser-Plasma Interactions in the Quantum Regime

TL;DR

This paper explores the complex nonlinear interactions between intense laser beams and quantum plasmas, revealing phenomena like instabilities, solitary wave structures, and electron acceleration relevant for high-intensity X-ray laser applications.

Contribution

It introduces a quantum plasma model using Klein-Gordon and Maxwell equations to analyze nonlinear laser-plasma interactions at nanometer scales.

Findings

Demonstrates collapse and acceleration of electrons during modulational instability

Shows the possibility of wake-field acceleration to relativistic speeds

Predicts localized solitary structures in quantum plasma

Abstract

We investigate the nonlinear interaction between a relativistically strong laser beam and a plasma in the quantum regime. The collective behavior of the electrons is modeled by a Klein-Gordon equation, which is nonlinearly coupled with the electromagnetic wave through the Maxwell and Poisson equations. This allows us to study the nonlinear interaction between arbitrarily large amplitude electromagnetic waves and a quantum plasma. We have used our system of nonlinear equations to study theoretically the parametric instabilities involving stimulated Raman scattering and modulational instabilities. A model for quasi-steady state propagating electromagnetic wavepackets is also derived, and which shows the possibility of localized solitary structures in the quantum plasma. Numerical simulations demonstrate the collapse and acceleration of the electrons in the nonlinear stage of the modulational instability, as well as the possibility of wake-field acceleration of the electrons to relativistic speeds by short laser pulses at nanometer length scales. The study has importance for the nonlinear interaction between a super-intense X-ray laser light and a solid-density plasma, where quantum effects are important.