Soft X-ray spectroscopy of highly charged silicon ions in dense plasmas

TL;DR

This study presents high-resolution soft X-ray spectra of highly charged silicon ions in dense plasmas created by ultra-intense laser pulses, with detailed line identification and comparison to existing databases.

Contribution

It provides new experimental spectra and collisional-radiative models for Si VI--Si XII ions in dense plasmas, enhancing understanding of their spectral features and plasma conditions.

Findings

Identified 53 prominent spectral lines with high precision.

Constructed collisional-radiative models that match experimental spectra.

Revealed increased spectral complexity in dense plasmas.

Abstract

Rich soft X-ray emission lines of highly charged silicon ions (Si VI--Si XII) were observed by irradiating an ultra-intense laser pulse with width of 200 fs and energy of $\sim$90 mJ on the solid silicon target. The high resolution spectra of highly charged silicon ions with full-width at half maximum (FWHM) of $\sim$0.3--0.4\AA is analyzed in wavelength range of 40--90 \AA . The wavelengths of 53 prominent lines are determined with statistical uncertainties being up to 0.005 \AA . Collisional-radiative models were constructed for Si VI -- Si XII ions, which satisfactorily reproduces the experimental spectra, and helps the line identification. Calculations at different electron densities reveal that the spectra of dense plasmas are more complicate than the spectra of thin plasmas. A comparison with the Kelly database reveals a good agreement for most peak intensities, and differences for a few emission lines.