Unveiling Mass Transfer in Solar Flares: Insights from Elemental Abundance Evolutions Observed by Chang'E-2 Solar X-ray Monitor

TL;DR

This study uses Chang'E-2 satellite data to analyze how elemental abundances change during solar flares, revealing new effects and providing insights into the mass transfer processes in solar atmospheres.

Contribution

It presents the first comprehensive observations of elemental abundance evolution throughout entire solar flares, including the first detection of the inverse FIP effect for Fe.

Findings

First observation of the inverse FIP effect for Fe during flares

Reaffirmation of the IFIP effect for Si

Detection of a rare depletion of elemental abundances in flare decay

Abstract

Understanding how elemental abundances evolve during solar flares helps shed light on the mass and energy transfer between different solar atmospheric layers. However, prior studies have mostly concentrated on averaged abundances or specific flare phases, leaving a gap in exploring the comprehensive observations throughout the entire flare process. Consequently, investigations into this area are relatively scarce. Exploiting the Solar X-ray Monitor data obtained from the Chang'E-2 lunar orbiter, we present two comprehensive soft X-ray spectroscopic observations of flares in active regions, AR 11149 and 11158, demonstrating elemental abundance evolutions under different conditions. Our findings unveil the inverse first ionization potential (IFIP) effect during flares for Fe for the first time, and reaffirm its existence for Si. Additionally, we observed a rare depletion of elemental abundances, marking the second IFIP effect in flare decay phases. Our study offers a CSHKP model-based interpretation to elucidate the formation of both the FIP and IFIP effects in flare dynamics, with the inertia effect being incorporated into the ponderomotive force fractionation model.