Homologous Helical Jets: Observations By IRIS, SDO, and Hinode and Magnetic Modeling With Data-Driven Simulations
Golub, L.; Tian, H.; Cheung, Mark C. M.; De Pontieu, B.; Tarbell, T. D.; Title, A. M.; Reeves, K. K.; Martínez-Sykora, J.; Carlsson, M.; McKillop, S.; Saar, S.; Testa, P.; Lemen, J.; Boerner, P.; Hurlburt, N.; Kleint, L.; Kankelborg, C.; Jaeggli, S.; Hansteen, V.; Fu, Y.; Wülser, J. P.
United States, Norway, Switzerland
Abstract
We report on observations of recurrent jets by instruments on board the Interface Region Imaging Spectrograph, Solar Dynamics Observatory (SDO), and Hinode spacecraft. Over a 4 hr period on 2013 July 21, recurrent coronal jets were observed to emanate from NOAA Active Region 11793. Far-ultraviolet spectra probing plasma at transition region temperatures show evidence of oppositely directed flows with components reaching Doppler velocities of ±100 km s-1. 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.