Magnetic Flux Cancelation as the Trigger of Solar Coronal-Hole Coronal Jets

TL;DR

This study demonstrates that magnetic flux cancelation at neutral lines is the primary trigger for minifilament eruptions that produce coronal-hole jets, based on detailed analysis of 13 events using multi-instrument observations.

Contribution

It provides direct observational evidence linking flux cancelation to the initiation of coronal-hole jets, extending previous findings from quiet-region jets.

Findings

Flux cancelation occurs at the neutral line prior to each jet.

Minifilaments are present before eruptions and reside along neutral lines.

Flux cancelation destabilizes minifilaments, triggering eruptions.

Abstract

We investigate in detail the magnetic cause of minifilament eruptions that drive coronal-hole jets. We study 13 random on-disk coronal hole jet eruptions, using high resolution X-ray images from Hinode/XRT, EUV images from SDO/AIA, and magnetograms from SDO/HMI. For all 13 events, we track the evolution of the jet-base region and find that a minifilament of cool (transition-region-temperature) plasma is present prior to each jet eruption. HMI magnetograms show that the minifilaments reside along a magnetic neutral line between majority-polarity and minority-polarity magnetic flux patches. These patches converge and cancel with each other, with an average cancelation rate of ~0.6 X 10$^18 Mx hr^{-1} for all 13 jets. Persistent flux cancelation at the neutral line eventually destabilizes the minifilament field, which erupts outward and produces the jet spire. Thus, we find that all 13 coronal-hole-jet-driving minifilament eruptions are triggered by flux cancelation at the neutral line. These results are in agreement with our recent findings Panesar et al 2016b for quiet-region jets, where flux cancelation at the underlying neutral line triggers the minifilament eruption that drives each jet. Thus from that study of quiet-Sun jets and this study of coronal hole jets, we conclude that flux cancelation is the main candidate for triggering quiet region and coronal hole jets