Abstract:
Lomnicky Stit data of 5303 U coronal green-line index (CI) are analysed for the years 1965–1994. The yearly quiet-Sun component (Q_ci) of CI estimated through the linear regression analysis of CI with sunspot numbers (SS) and CI with Ca plage index (CA) are found to vary with the 11-year solar activity cycle. Comparison of Q_ci with the quiet Sun component of 10.7 cm flux (Q_10.7) revealed that the Q_ci contributes principally to the entire CI, while Q_10.7 assumes much smaller values compared to its yearly averages. The slowly varying component of 5303 Ú emission associated with sunspots and plages seems to be nearly absent in CI. This aspect is also confirmed through the multiple-linear regression analysis of CI with sunspots and plages. The delayed response of green corona to both sunspots and plages also revealed similar results.
