Solar Orbiter and SDO Observations, and a Bifrost Magnetohydrodynamic Simulation of Small-scale Coronal Jets

Abstract

We report high-resolution, high-cadence observations of five small-scale coronal jets in an on-disk quiet Sun region observed with Solar Orbiter’s EUI/HRI _EUV in 174 Å. We combine the HRI _EUV images with the EUV images of SDO/AIA and investigate the magnetic setting of the jets using coaligned line-of-sight magnetograms from SDO/HMI. The HRI _EUV jets are miniature versions of typical coronal jets as they show narrow collimated spires with a base brightening. Three out of five jets result from a detectable minifilament eruption following flux cancelation at the neutral line under the minifilament, analogous to coronal jets. To better understand the physics of jets, we also analyze five small-scale jets from a high-resolution Bifrost MHD simulation in synthetic Fe ix /Fe x emissions. The jets in the simulation reside above neutral lines and four out of five jets are triggered by magnetic flux cancelation. The temperature maps show evidence of cool gas in the same four jets. Our simulation also shows the signatures of opposite Doppler shifts (of the order of ±10 s of km s ^−1 ) in the jet spire, which is evidence of untwisting motion of the magnetic field in the jet spire. The average jet duration, spire length, base width, and speed in our observations (and in synthetic Fe ix /Fe x images) are 6.5 ± 4.0 min (9.0 ± 4.0 minutes), 6050 ± 2900 km (6500 ± 6500 km), 2200 ± 850 km, (3900 ± 2100 km), and 60 ± 8 km s ^−1 (42 ± 20 km s ^−1 ), respectively. Our observation and simulation results provide a unified picture of small-scale solar coronal jets driven by magnetic reconnection accompanying flux cancelation. This picture also aligns well with the most recent reports of the formation and eruption mechanisms of larger coronal jets.

Keywords

• Solar magnetic fields
• Solar magnetic reconnection
• Jets
• Solar corona
• Solar chromosphere