Coronal index of solar activity VII, years 1988–1991

Abstract

A brief description is given of the coronal index of solar activity (CI) derived from ground-based observations of the green coronal line 530.3 nm (FeXIV) and its computation. The final data of CI are presented in graphical form over the period 1988–1991. The maximum of CI coincided with the Wolf number in cycle 22, and no second maximum, sometimes seen two years after the first one, was observed in this cycle.