Forward Raman Scattering and Self-Modulation instabilities of lasers in magnetized tapered plasma channels

TL;DR

This paper analyzes how plasma density, magnetic fields, and laser polarization affect the growth of instabilities like Raman scattering and self-modulation in tapered magnetized plasma channels, crucial for stable laser propagation.

Contribution

It provides a detailed theoretical and numerical analysis of instability growth rates influenced by plasma and laser parameters in tapered magnetized plasma channels.

Findings

Higher plasma density and laser intensity increase instability growth rates.

Magnetic field strength enhances or suppresses instabilities depending on laser polarization.

Reducing growth rates can improve stable laser propagation in plasma channels.

Abstract

The propagation of laser pulses in tapered magnetized plasma channels is analyzed using the fluid theory of cold plasmas. This study focuses on laser propagation's key instabilities: forward Raman scattering and self-modulation instability. The influence of plasma density, laser intensity, dc magnetic field strength, and laser polarization on the growth rates of these instabilities is thoroughly examined. Analytical and numerical computations of the number of e-foldings for forward Raman scattering are performed to quantify its impact. The results reveal that increased plasma density and laser intensity significantly enhance the growth rates of these instabilities, leading to amplified Raman-scattered wave intensity and modulation of the laser envelope. Moreover, the strength of the dc magnetic field plays a pivotal role: it boosts instability growth rates for right-handed circularly polarized laser pulses while suppressing them for left-handed circularly polarized pulses. These findings highlight that reducing the growth rates of instabilities can facilitate the stable propagation of laser pulses in tapered plasma channels.