Doppler Dimming and Brightening Effects in Solar Prominences

TL;DR

This study investigates how Doppler dimming and brightening caused by bulk motions in solar prominences affect spectral line profiles, emphasizing the significance of horizontal velocities in modeling these effects.

Contribution

It introduces a comprehensive analysis of Doppler effects in prominences using 1D NLTE radiative transfer models, highlighting the importance of horizontal motions.

Findings

Horizontal velocities are as important as radial velocities in Doppler effects.

Horizontal motions significantly influence spectral line profiles.

Accounting for horizontal velocities is crucial for accurate prominence modeling.

Abstract

We explored the impact that Doppler dimming and brightening effects from bulk motions of solar prominences have on the formation of Lya, Ha, and MgII h line profiles. We compared two schemes in which these effects manifest; when the prominence is moving radially away from the solar surface (radial case), and when the prominence is moving parallel to the solar surface (horizontal case). To do this, we analysed 13,332 model profiles generated through the use of the 1D NLTE (i.e. departures from Local Thermodynamic equilibrium) radiative transfer (RT) code Promweaver, built on the Lightweaver NLTE RT framework to mimic the behaviour and output of the 1D NLTE RT code PROM. We found that horizontal velocities are just as, or more important than radial velocities. This demonstrates that horizontal velocities need to be accounted for when attempting to do any sort of forward modelling.