Active region evolution and solar flux variations

Abstract

The goal of this study is to relate the changes in the solar radiative output to the growth and decay of magnetic active regions. We will test the assumption that each index of radiation variability is a convolution of an active-region magnetic driving function and a response function. The first step has been to identify the appropriate driving function. This driving function was assumed to have been data from the magnetic active regions derived from the Mount Wilson daily magnetograms (Howard, 1989). The daily magnetic reports were sorted to give active-region sequences. To estimate the magnetic flux of active regions outside the observing window, (i.e., behind the limb) we fit the data to a growing-and-decaying exponential function, which permits independent growth and decay. This double exponential gives reasonable fats to the observed temporal evolution of active-region magnetic flux.