On the correlation of coronal green-line intensity and solar wind velocity

Abstract

Cross-correlation functions have been computed between green-line intensity (Kislovodsk) and Vela solar wind velocity January–June 1967. They are calculated separately for east and west limb observations in 5° latitude increments, and the solar wind velocites are correlated at their estimated emission times by correcting for the plasma Earth-Sun transit time using the observed velocities. The cross-correlation patterns appear to be dominated by two competing effects: a tendency of quasi-stationary green-line emission and solar wind velocity to anti-correlate; and a tendency of transient green-line emission and solar wind velocity enhancements to correlate positively. We also find evidence for simultaneous (same-day) emission brightenings over 2 to 4 limb quadrants. It is therefore recommended that, following a well-known practice in solar terrestrial studies, recurrent and transient events in both solar wind and green-line emissions should be studied separately.