Generation of mega-gauss axial and azimuthal magnetic fields in a solid plasma by ultrahigh intensity, circularly polarised femtosecond laser pulses

TL;DR

This paper demonstrates that ultrahigh intensity, circularly polarized femtosecond laser pulses can generate both axial and azimuthal mega-gauss magnetic fields in solid plasmas, revealing new magnetic field dynamics.

Contribution

It provides experimental and simulation evidence that circular polarization produces both axial and azimuthal magnetic fields of similar strength in solid plasmas, a novel finding.

Findings

Circular polarization generates comparable axial and azimuthal magnetic fields.

Angular electron distributions differ significantly between polarization states.

Magnetic fields exhibit turbulent evolution over time.

Abstract

The interaction of intense linearly polarized femtosecond laser pulses with solids is known to generate azimuthal magnetic fields, while circularly polarized light has been shown to create axial fields. We demonstrate through experiments and particle-in-cell simulations that circularly polarized light can generate both axial and azimuthal fields of comparable magnitude in a plasma created in a solid. Angular distributions of the generated fast electrons at target front and rear show significant differences between the results for the two polarization states, with circular polarization enforcing more axial confinement. The measurement of the spatial distribution of both types of magnetic fields captures their turbulent evolution.