Experimental Study of Nanosecond Laser-Generated Plasma Channels

T Levato ,Antonio Lucianetti,Filip Grepl,Haris Zulic,Michal Nevrkla,L Giuffrida ,Martin Divoký ,Muhammad Fahad Nawaz ,Jan Pilař ,Tomáš Mocek ,Martin Hanuš ,D Margarone

doi:10.3390/app10124082

Abstract

Generation of plasma-channels by interaction of gas targets with nanosecond laser beams was investigated experimentally. Such laser-generated plasma channels are very promising for subsequent guiding of high peak power femtosecond laser pulses, over several tens of centimeters, as required in laser wake field electron-acceleration (LWFA). The experimental setup was based on the use of a cylindrical lens (100 mm of focal length) with the aim of proposing a technical solution easy to be integrated into a compact experimental setup for acceleration of multi-GeV electron beams using high peak-power laser systems. A pilot experiment, showing production of asymmetric plasma channels over a length of several millimeters in N and Ar targets with initial neutral-gas atomic density around 5 × 1019 cm−3, is reported. Plasma effective threshold formation was estimated, along with future optimization of the optical setup for a symmetrization of such plasma channel. Scalability of this concept to several tens of centimeters is preliminarily discussed, along with the corresponding critical requirements for an optimal LWFA scheme.

Highlights

After the advent of the laser chirped pulse amplification (CPA) technique [1] giving rise to high peak power femtosecond pulses, the laser wake field acceleration (LWFA) concept [2] has become a routinely used experimental technique to generate electron beams by means of such ultrashort laser pulses [3]
10-ns laser pulse operating at aa wavelength of 1030
As laser pulse operating at wavelength of nm with with variable variable energy in target

Summary

Introduction

After the advent of the laser chirped pulse amplification (CPA) technique [1] giving rise to high peak power femtosecond pulses, the laser wake field acceleration (LWFA) concept [2] has become a routinely used experimental technique to generate electron beams by means of such ultrashort laser pulses [3]. The main advantage in LWFA is represented by the presence of ultrahigh electric fields (GV/m–TV/m) generated by a plasma-wave, known as “wakefield”, which is a result of ponderomotive forces generated by a driving short laser pulse during its propagation into a pre-formed under-dense plasma. Electrons injected in such a wave can reach relativistic energies by being in phase with the wakefield and propagating behind the laser pulse, be accelerated to multi-GeV energies until the process is sustained.

Methods

Discussion

Conclusion