THE NATURE OF SOLAR POLAR RAYS

摘要

We use time series observations from the Solar and Heliospheric Observatory and Yohkoh spacecraft to study solar polar rays. Contrary to our expectations, we find that the rays are associated with active regions on the Sun and are not features of the polar coronal holes. They are extended, hot plasma structures formed in the active regions and projected onto the plane of the sky above the polar coronal holes. We present new observations and simple projection models that match long-lived polar ray structures seen in limb synoptic maps. Individual projection patterns last for at least five solar rotations.