The Mg II index: A proxy for solar EUV

Abstract

This paper shows that the Mg II core-to-wing ratio is a better proxy for Solar Extreme Ultraviolet (EUV) radiation, between 25 and 35 nm than is the F10.7 index. The He II 30.4 nm solar emission, by itself, is an important source of energy for the upper atmosphere. We will compare the NOAA Mg II Index and the F10.7 Index to the He II 30.4 data taken with the CELIAS/Solar EUV Monitor (SEM) on the Solar and Helospheric Observatory (SOHO).