Cascade emission in electron beam ion trap plasma of W$^{25+}$ ion

TL;DR

This study investigates how cascade emission influences the spectral lines of W$^{25+}$ ions in electron beam ion trap plasma, revealing selective intensity boosts and structural changes in the emission spectrum.

Contribution

It demonstrates the specific impact of cascade emission on spectral line intensities and structures in W$^{25+}$ ion spectra using a collisional-radiative model.

Findings

Cascade emission boosts a few spectral lines in the 10-3 nm range.

Cascade emission causes the disappearance of line structures around 6 nm.

The strongest lines are from 4d^9 4f^4 to 4f^3 transitions.

Abstract

Spectra of the W$^{25+}$ ion are studied using the collisional-radiative model (CRM) with an ensuing cascade emission. It is determined that the cascade emission boosts intensities only of a few lines in the $10 - 3$ nm range. The cascade emission is responsible for the disappearance of structure of lines at about 6 nm in the electron beam ion trap plasma. Emission band at 4.5 to 5.3 nm is also affected by the cascade emission. The strongest lines in the CRM spectrum correspond to $4d^{9} 4f^{4} \rightarrow 4f^{3}$ transitions, while $4f^{2} 5d \rightarrow 4f^{3}$ transitions arise after the cascade emission is taken into account.