Evidence of Magnetic Reconnection along Coronal Hole Boundaries

Abstract

The present study reveals for the first time the existence of bidirectional jets, which are a signature of magnetic reconnection, occurring along coronal hole boundaries. The Solar Ultraviolet Measurement of Emitted Radiation spectrometer observations obtained in the N IV 765.15 A(1.3 x 10^5 K) and Ne VIII 770.42 A (6 x 10^5 K) emission lines in an equatorial extension of a polar coronal hole, known as the "Elephant's Trunk" coronal hole, show small regions of a few arcseconds size with strong blue-and redshifted emission reaching Doppler shifts of up to 150 km/s , i.e., bidirectional jets. The jets' number density along coronal hole boundaries was found to be about 4-5 times higher with respect to the quiet Sun.