Enhanced x-ray emission arising from laser-plasma confinement by a strong transverse magnetic field

TL;DR

This study combines experiments and 3D MHD simulations to show that a strong transverse magnetic field confines laser-ablated plasma, increasing density and heating, which enhances x-ray emission significantly.

Contribution

It demonstrates the effect of strong transverse magnetic fields on plasma confinement and x-ray emission, combining experimental data with numerical simulations for the first time.

Findings

Magnetic confinement occurs within 2 ns of plasma expansion.

Increased magnetic field strength leads to more plasma confinement and heating.

X-ray emissivity is significantly enhanced due to magnetic confinement.

Abstract

We analyze, using experiments and 3D MHD numerical simulations, the dynamics and radiative properties of a plasma ablated by a laser (1 ns, 10$^{12}$-10$^{13}$ W/cm$^2$) from a solid target, as it expands into a homogeneous, strong magnetic field (up to 30 T) transverse to its main expansion axis. We find that as soon as 2 ns after the start of the expansion, the plasma becomes constrained by the magnetic field. As the magnetic field strength is increased, more plasma is confined close to the target and is heated by magnetic compression. We also observe a dense slab that rapidly expands into vacuum after ~ 8 ns; however, this slab contains only ~ 2 % of the total plasma. As a result of the higher density and increased heating of the confined plasma, there is a net enhancement of the total x-ray emissivity induced by the magnetization.