A Discussion on solar studies with special reference to space observations - Interpretation of extreme ultraviolet emissions from the Sun

Abstract

The purpose of this review is to consider the analysis of extreme u.v. space observations for the interpretation of the Quiet Sun (Q.), active regions (a.r.) and flares (fl.). The three components must be segregated from one another using the observational data that exists. We cannot count on having every type of observation for every occasion. It becomes necessary to make some simple assumptions concerning the components Q, a.r. and fl. in order that they can be measured consistently. I give below some descriptive models which are complete enough to represent the complex varying Sun at all times but simple enough to be expressed quantitatively in a few numbers. The aim will be to interpret all extreme u.v. observations on the basis of these models and to regard them as the norm. Exceptional phenomena would be regarded as variations from the models. Ideally all intensity and flux measurements would be made within individual spectrum lines or in continua at specified wavelengths. However, many valuable observations are based on broad spectral regions and it is necessary to devise methods for interpreting them.