New Calculations of Stark Broadened Profiles for Neutral Helium Lines Using Computer Simulations

TL;DR

This paper introduces advanced computer simulation methods to calculate Stark broadened profiles for neutral helium lines, improving the representation of the atomic environment and comparing results with existing literature.

Contribution

It presents novel simulation techniques that incorporate ion-electron unification, ion dynamics correction, and other factors to enhance accuracy of helium line broadening profiles.

Findings

Simulations match observed profiles for certain helium lines.

Narrow lines are more challenging to simulate accurately.

Comparison with literature validates the new approach.

Abstract

We present new calculations of Stark broadened profiles for neutral helium lines using computer simulations that include some important aspects aimed at better representing the dynamical environment of the helium atom. These include the unification of ion and electron treatment, the correction for ion dynamics, the transition of the electron contribution to broadening from the core to the wings of the profile, the numerical integration of the time evolution operator of helium perturbed by a fluctuating electric field, the Debye correction for the correlation of the motion of charged perturbers, local density variations, and particle reinjection. We compare the results of our simulations for the He I $\lambda\lambda$4471 and 4922 lines with other results published in the literature. We also test our simulation environment for narrow lines (He I $\lambda\lambda$5877 and 6678) and broader lines (He I $\lambda\lambda$4026 and 4144). We find that the narrow lines are more difficult to produce adequately than the the broader ones.