Investigating the Origins of the Solar Wind: Understanding Plasma Composition and Fractionation with Solar Orbiter SPICE

The First Ionization Potential (FIP) bias is a critical diagnostic for solar plasma composition, offering insights into the mechanisms shaping the solar atmosphere and the solar wind. Previous studies have highlighted the time-dependent nature of the FIP bias. In this study, we aim to understand how the FIP bias evolves over time and identify its key drivers and parameters. Using data from the SPICE (Spectral Imaging of the Coronal Environment) instrument onboard Solar Orbiter, we analyze Extreme Ultra-Violet (EUV) observations of active regions (ARs) captured from December 20th to 22nd, 2022. These observations include spectral lines from ions emitting at temperatures spanning log T = 4.2 to log T =6.0, covering a wide range of structures and phenomena.

We examine the evolution of physical quantities such as intensity, electron temperature, and elemental fractionation within ARs present in the field of view (FOV). Special attention is given to intermediate-FIP elements, such as sulfur and carbon, in key regions of interest. By focusing on the Mg/Ne ratio—a proxy for higher temperatures and atmospheric heights—and lower-temperature/upper-chromosphere ratios (S/N and C/O), we investigate the dependence of FIP bias on time, temperature, and atmospheric height. Finally, we compare these observations with predictions from the ponderomotive force model, providing insights into the physical processes driving FIP bias variations.