Evidence for Polar Jets as Precursors of Polar Plume Formation

Abstract

Observations from the Hinode/XRT telescope and STEREO/SECCHI/EUVI are utilized to study polar coronal jets and plumes. The study focuses on the temporal evolution of both structures and their relationship. The data sample, spanning 2007 April 7-8, shows that over 90% of the 28 observed jet events are associated with polar plumes. EUV images (STEREO/SECCHI) show plume haze rising from the location of approximately 70% of the polar X-ray (Hinode/XRT) and EUV jets, with the plume haze appearing minutes to hours after the jet was observed. The remaining jets occurred in areas where plume material previously existed, causing a brightness enhancement of the latter after the jet event. Short-lived, jetlike events and small transient bright points are seen (one at a time) at different locations within the base of preexisting long-lived plumes. X-ray images also show instances (at least two events) of collimated thin jets rapidly evolving into significantly wider plumelike structures that are followed by the delayed appearance of plume haze in the EUV. These observations provide evidence that X-ray jets are precursors of polar plumes and in some cases cause brightenings of plumes. Possible mechanisms to explain the observed jet and plume relationship are discussed.