Authors: Tania Varesano (CU Boulder / SwRI), Don Hassler (SwRI), Joe Plowman (SwRI), Natalia Zambrana-Prado (Mullard Space Science Laboratory)

The FIP (First Ionization Potential) bias is one of the most relevant diagnostics for solar plasma composition. Previous studies have demonstrated that the FIP bias is dependent on several variables. In this study, we attempt to answer the following question: how does the FIP bias evolves over an emerging active region, and what are the most plausible scenarios to explain the observations? We investigate active region (AR) observations recorded by the Extreme Ultra-Violet (EUV) spectrometer SPICE (Spectral Imaging of the Coronal Environment) instrument on-board Solar Orbiter. These observations include a set of EUV lines from ions emitting at temperatures ranging from logT=4.2 to logT=6.0. We focus on the period of December 20th to 22nd 2022 and look at the evolution of intensity and fractionation of elements within the passing AR present in the field of view (FOV). We investigate the time dependence of the FIP bias and its behavior in different parts of the AR.  

We focus on two Mg / Ne ratios as a proxy for higher temperatures and higher heights in the atmosphere and three lower temperature / upper chromosphere ratios (S/N, S/O and C/O).

We investigate the FIP bias evolution with time but also with location in the active region and compare the observations with the ponderomotive force model. We find good correlation between the model and results, encouraging an Alfvén-wave driven fractionation of the plasma.