The Extended Solar Cycle Tracked High into the Corona

TL;DR

This study tracks extended solar cycle activity into the corona using white-light coronagraphs, revealing that activity zones can be observed high in the corona with consistent peak latitudes, and that the equatorward drift varies with height.

Contribution

It demonstrates that coronal activity zones are observable high in the corona and compares their behavior across different emission lines, providing new insights into solar cycle dynamics.

Findings

Coronal activity zones are trackable high into the corona.

The peak latitude of activity remains similar at all heights.

The equatorward drift is faster at greater heights.

Abstract

We present observations of the extended solar cycle activity in white-light coronagraphs, and compare them with the more familiar features seen in the Fe XIV green-line corona. We show that the coronal activity zones seen in the emission corona can be tracked high into the corona. The peak latitude of the activity, which occurs near solar maximum, is found to be very similar at all heights. But we find that the equatorward drift of the activity zones is faster at greater heights, and that during the declining phase of the solar cycle, the lower branch of activity (that associated with the current cycle) disappears at about 3 Ro. This implies that that during the declining phase of the cycle, the solar wind detected near Earth is likely to be dominated by the next cycle. The so-called "rush to the poles" is also seen in the higher corona. In the higher corona it is found to start at a similar time but at lower latitudes than in the green-line corona. The structure is found to be similar to that of the equatorward drift.