Micron-scale Fast Electron Filamentation and Recirculation determined from Rear Side Optical Emission in High Intensity Laser-Solid Interactions

TL;DR

This study investigates relativistic electron transport in high-intensity laser-solid interactions by analyzing polarized optical emissions, revealing micron-scale filamentation and electron recirculation effects.

Contribution

It provides new insights into electron filamentation and recirculation mechanisms using rear surface optical emission measurements in laser-solid experiments.

Findings

Detection of polarized optical transition radiation indicating electron transport.

Observation of a polarized halo suggesting electron recirculation.

Evidence of micron-scale electron filaments from emission angle variation.

Abstract

The transport of relativistic electrons generated in the interaction of petawatt class lasers with solid targets has been studied through measurements of the optical emission from their rear surface. The high degree of polarization of the emission indicates that it is predominantly optical transition radiation. A halo that surrounds the main region of emission is also polarized, and is attributed to the effect of electron recirculation. The variation of the amplitude of the transition radiation with respect to observation angle provides evidence for the presence of {$\mu$m-size} filaments.