Fig. 2
From: A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations
Correlation between the coronal to photospheric composition ratio and the F10.7 cm radio flux. The evolution of the 27-day Carrington rotation running average ratio of the coronal (A c) to photospheric (A p) composition in the Sun’s corona between April 2010 and May 2014 (red) and the evolution of the 27-day Carrington rotation running average F10.7 cm radio flux (blue) during the same period. We show the correlation coefficient in the legend, and the uncertainty in the composition measurements with an error bar. Note that A c/A p is measured using the high first ionization potential (FIP) element Ne only. The increase in A c/A p appears most obvious when activity picks up after the end of the solar minimum (during 2010–11) and appears to level off thereafter while still closely tracking the F10.7 cm activity peaks. The error bar is the dispersion (standard deviation) in A c/A p computed from variations in the best fits to the irradiance data from a large number of random trials (see “Methods” section for more details)
