Weak Bidirectional Outflows and Flare Current Sheet in a Solar Coronal Jet Driven by the Eruption of a Minifilament

Different from the classical emerging-flux model for solar jets, recent studies proposed that the great majority of solar coronal jets are triggered by minifilament eruptions and two magnetic reconnection processes should take place during the course, named as external reconnection (breakout reconnection) and internal reconnection (flare reconnection). With the excellent data of the Solar Dynamics Observatory, we present the observational signatures of these two magnetic reconnection processes during a solar coronal jet that occurred in a huge coronal hole of northern hemisphere. The jet was triggered by the eruption of a minifilament that located at a coronal bright point in the coronal hole. Weak bidirectional outflows were observed when the erupting minifilament approached the ambient open field, ejecting along the triggered jet spire and the jet base simultaneously. In addition, a flare current sheet occurred after the eruption of the minifilament, connecting the jet spire and the jet bright point (or flare). We suggest the occurrence of the weak bidirectional outflows and the flare current sheet correspond to the external and the internal reconnections, respectively. Prior to the eruption of the minifilament and the jet, photospheric magnetic flux cancellation maintained for more than 7 hr in the source region, and the positive flux decreased for about 28.6% during this period. So, consistent with the recent observations, the trigger mechanism of the minifilament eruption and the following jet in this event may be flux cancellation rather than flux emergence.

Automated summary

Different from the classical emerging-flux model, recent studies propose that solar coronal jets are triggered by minifilament eruptions and involve two magnetic reconnection processes, namely external and internal reconnections. Observational signatures of these two reconnection processes are presented for a solar coronal jet, triggered by a minifilament eruption in a coronal hole, using data from the Solar Dynamics Observatory. Weak bidirectional outflows and a flare current sheet are observed, corresponding to the external and internal reconnections, respectively.