Evolution of anomalous coronal elemental composition in AR 12673

The coronae of the Sun and solar-type stars are dominated by the FIP effect while more active stars such as M-dwarfs have inverse-FIP effect dominated coronae. This means that certain elements (those with low first ionization potential or FIP) are enhanced (FIP effect) or depleted (IFIP effect) in the corona relative to their photospheric composition. In the most complex and X-flare active region of solar cycle 24, AR 12673, we observe patches of inverse FIP composition which we link to flux emergence into pre-existing complex field and the resulting sub-surface interaction between the two. On 6 September 2017, the last major episode of new flux emergence in this highly complex beta-gamma-delta active region produces a runaway umbra reaching velocities up to 0.5 km/s. The IFIP plasma above the runaway umbra was observed by Hinode/EIS for several hours. We analyse how the composition anomaly formed and evolved using Hinode/EIS spectral scans. We propose that IFIP plasma is created by fast mode waves coming from below the chromosphere. Such fast mode waves can be generated by sub-photospheric reconnection between emerging and pre-existing fields. Although we only glimpse IFIP signatures produced by this interaction in patches on the Sun, on highly active M-stars it may be the dominant process.