Hinode/EIS Line Profile Asymmetries And Their Relationship with the Distribution of SDO/AIA Propagating Coronal Disturbance Velocities

TL;DR

This study investigates coronal EUV line profile asymmetries using joint Hinode/EIS and SDO/AIA observations, revealing consistent secondary emission components related to propagating disturbances across different temperatures.

Contribution

It demonstrates that line profile asymmetries are present in all studied spectral lines and are linked to propagating coronal disturbances, expanding understanding beyond previous focus on only the hottest lines.

Findings

Asymmetries are present in all spectral lines studied.

Secondary emission components are consistent with propagating disturbances.

No evidence of broader secondary components than the main emission.

Abstract

Using joint observations from Hinode/EIS and the Atmospheric Imaging Array (AIA) on the Solar Dynamics Observatory we explore the asymmetry of coronal EUV line profiles. We find that asymmetries exist in all of the spectral lines studied, and not just the hottest lines as has been recently reported in the literature. Those asymmetries indicate that the velocities of the second emission component are relatively consistent across temperature and consistent with the apparent speed at which material is being inserted from the lower atmosphere that is visible in the SDO/AIA images as propagating coronal disturbances. Further, the observed asymmetries are of similar magnitude (a few %) and width (determined from the RB analysis) across the temperature space sampled and in the small region studied. Clearly, there are two components of emission in the locations where the asymmetries are identified in the RB analysis, their characteristics are consistent with those determined from the SDO/AIA data. There is no evidence from our analysis that this second component is broader than the main component of the line.