The Green Corona Index and Soft X-Ray Flux

We present the behaviour of the coronal index (CI) of solar activity over the period 1986–(May) 1996. These data are not only a good tool for studying the activity of the Sun as a star, but they also represent an invaluable source of information in our quest to understand the properties of the heliosphere as a whole. Having compared the variations of CI and of the solar 0.05–0.8 nm soft X-ray flux over the period 1986–1995 we did not find any significant correlation between the two quantities. This favours a scenario in which the sources of the soft X-ray flux are small-scale regions of the corona, and processes of both ionization and recombination do not occur in the same volume of the solar corona as for the green corona.