Homologous Helical Jets: Observations by IRIS, SDO and Hinode and Magnetic Modeling with Data-Driven Simulations

TL;DR

This study combines multi-instrument observations and data-driven simulations to analyze recurrent helical jets from an active region, revealing magnetic flux emergence and twist as key drivers of jet formation.

Contribution

It provides new insights into the magnetic mechanisms behind recurrent helical jets through combined observational and simulation approaches.

Findings

Jets exhibit oppositely directed flows with Doppler velocities of ±100 km/s.

All jets show helical motion of the same sense.

Magnetic flux emergence supplies the twist necessary for jet formation.

Abstract

We report on observations of recurrent jets by instruments onboard the Interface Region Imaging Spectrograph (IRIS), Solar Dynamics Observatory (SDO) and Hinode spacecrafts. Over a 4-hour period on July 21st 2013, recurrent coronal jets were observed to emanate from NOAA Active Region 11793. FUV spectra probing plasma at transition region temperatures show evidence of oppositely directed flows with components reaching Doppler velocities of +/- 100 km/s. Raster Doppler maps using a Si IV transition region line show all four jets to have helical motion of the same sense. Simultaneous observations of the region by SDO and Hinode show that the jets emanate from a source region comprising a pore embedded in the interior of a supergranule. The parasitic pore has opposite polarity flux compared to the surrounding network field. This leads to a spine-fan magnetic topology in the coronal field that is amenable to jet formation. Time-dependent data-driven simulations are used to investigate the underlying drivers for the jets. These numerical experiments show that the emergence of current-carrying magnetic field in the vicinity of the pore supplies the magnetic twist needed for recurrent helical jet formation.