Hysteresis and non-linearity between solar EUV and 10.7 cm fluxes

Abstract

It has been reported in literature that for values of the solar 2800 MHz radio flux (10.7 cm, F10) exceeding 200. Solar EUV values show saturation effects. This aspect was examined using EIJV data obtained by the AE-E satellites during 1977-1981 and the SEM/SOHO satellite data from 1996 onwards up to date. It was noticed that the saturation effect were not always seen in sequences of days when F10 exceeded 200. In both of these data sets, near solar maximum, there were slight differences in the evolution of the EUV and F10. Either their peaks were slightly displaced and/or their evolution profiles were different, the F10 remaining steady for several months after peaking (flat peak), while the EUV started decreasing soon after peaking, indicating probable 'hysteresis' loops.