Authors: Floyd, L. E., D. R. McMullin and L. C. Herring
Reference: Proc. of the SOHO 11 Workshop, ed A. Wilson, ESA SP-508, 197. (2002)
Abstract:
Measurements from the Solar EUV Monitor (SEM), a component experiment of the Charge, Element, and Isotope System
(CELIAS) aboard SOHO are analyzed in terms of coincident solar indices and simultaneous measurements made by other
experiments. Earlier studies (e.g. Viereck et al., Floyd et al.) have shown the strong correspondence between the Mg
II core-to-wing ratio and the SEM first order irradiance and by extension the inferred He II 30.4 nm emission line
flux. These studies are extended by comparisons with the F10.7 (cm) radio flux, soft and hard x-ray fluxes as
measured by the GOES satellites and the energetic solar proton flux also measured by GOES. We find that the solar
protons are the cause of nearly all of the “spikes” in the first order flux and occur during proton flares. By
contrast, solar protons do not have a significant effect on the measured central order flux, a channel sensitive to
radiation in the 0.1–50 nm range. Solar x-rays explain a large portion of the central order flux, but do not affect
the first order flux. The goal of these studies is to improve the time dependent models of EUV flux and will be
extended to include the newly available SOHO EIT-derived irradiances.