Propagation Characteristics of High-Power Vortex Laguerre-Gaussian Laser Beams in Plasma

Zhili Lin,Xudong Chen,Jixiong Pu,Weibin Qiu

doi:10.3390/app8050665

Abstract

The propagation characteristics of high-power laser beams in plasma is an important research topic and has many potential applications in fields such as laser machining, laser-driven accelerators and laser-driven inertial confined fusion. The dynamic evolution of high-power Laguerre-Gaussian (LG) beams in plasma is numerically investigated by using the finite-difference time-domain (FDTD) method based on the nonlinear Drude model, with both plasma frequency and collision frequency modulated by the light intensity of laser beam. The numerical algorithms and implementation techniques of FDTD method are presented for numerically simulating the nonlinear permittivity model of plasma and generating the LG beams with predefined parameters. The simulation results show that the plasma has different field modulation effects on the two exemplified LG beams with different cross-sectional patterns. The self-focusing and stochastic absorption phenomena of high-power laser beam in plasma are also demonstrated. This research also provides a new means for the field modulation of laser beams by plasma.

Highlights

The complex interaction of high-power laser with plasma has become a popular research topic due to its various applications in science and technology, including laser-driven inertial confined fusion (ICF) [1], laser-driven accelerators [2] and laser machining [3]
The physical model of permittivity with ponderomotive nonlinearity given by Equation (8) determines that the refractive index of plasma is smaller at the place where the light intensity is lower and larger where the light intensity is stronger
The simulation results about the 3D dynamic interaction of high-power LG beams with plasma are illustrated and discussed

Summary

Introduction

The complex interaction of high-power laser with plasma has become a popular research topic due to its various applications in science and technology, including laser-driven inertial confined fusion (ICF) [1], laser-driven accelerators [2] and laser machining [3]. The main research areas have focused on the propagation characteristics of high-power laser beams in plasma [4,5,6]. Sharma et al [9] have found that the propagation characteristics of an intense laser beam in plasma depend on the power and width of the beam and the ratio of plasma frequency and light wave frequency. Wang et al [10] have investigated the propagation characteristics of a Gaussian laser beam in unmagnetized cold plasmas, based on the theory of ponderomotive nonlinearity. They applied the Wentzel–Kramers–Brillouin (WKB) method to study the propagation characteristics of a Gaussian laser beam in cold plasma [11]

Methods

Results

Discussion

Conclusion