FIP Bias Evolution in an Emerging Active Region as observed in SPICE Synoptic Observations

TL;DR

This study analyzes the evolution of elemental abundances in a solar active region using spectroscopic data from Solar Orbiter, comparing observations with a ponderomotive force model to understand plasma fractionation driven by Alfvén waves.

Contribution

It provides the first detailed temporal analysis of FIP bias evolution in an emerging active region, linking observations with wave-driven fractionation models.

Findings

Coronal abundances are observed in fan loops, loop footpoints, and active region boundaries.

Active region core shows more photospheric-like composition.

Magnesium to neon FIP bias increases by about 50% over two days.

Abstract

We investigate the time evolution of relative elemental abundances in the context of the first ionization potential effect focusing on an active region. Our aim is to characterize this evolution in different types of solar active region structures as well as in different atmospheric layers. We wish to assert how the measured changes relate to different magnetic topologies by computing abundance enhancement in different conditions using the ponderomotive force model. Leveraging spectroscopic observations from the Spectral Imaging of the Coronal Environment instrument on board Solar Orbiter, we use extreme ultraviolet lines from ions formed across a broad temperature range--from the upper chromosphere to the low corona--and we perform relative abundance ratios following differential emission measure analysis. This methodology yields relative abundance maps from low, intermediate, and high first ionization potential elements. We obtain the temporal evolution of a number of abundance ratios for different structures on the Sun. We compare these results with the outcomes of the ponderomotive force model. We find good correlation between the model and our results, suggesting an Alfv\'en-wave driven fractionation of the plasma. Fan loops, loop footpoints and active region boundaries exhibit coronal abundances, while the active region core shows more photospheric-like composition. A slow and steady increase in the magnesium to neon relative first ionization potential bias values is observed, starting around 1.5 and increasing by about 50\% after two days. The sulfur to oxygen evolution coupled with the model brings evidence of resonant waves fractionating the plasma in transition region structures.