Mini statistical study of chemical composition in solar active regions

In the solar corona, elements with a low first ionisation potential (FIP) have been observed to have an increased abundance compared to the photosphere. This phenomenon is known as the FIP effect and the degree of enhancement is measured using the FIP bias parameter. In this study, the first full Sun FIP bias map, taken between 16-18 January 2013, is analysed to produce a mini statistical study of metal enhancement in the corona in the 9 active regions present on the surface of the Sun at the time. Results showed that the FIP bias is linked to three main factors. First, FIP bias was observed to increase with the total magnetic flux of the active region. Second, the following polarity was observed to have a higher FIP bias than the leading polarity. This could be explained by the magnetic field being more dispersed in the following than the leading polarity. Third, the FIP bias dependence with magnetic flux density was found to increase with magnetic flux density in the low magnetic flux density region, but then decrease in the regions of very concentrated magnetic field, i.e. regions with sunspots.