Browsing by Author "Cheung, Mark C.M."

Now showing 1 - 1 of 1

Homologous Helical Jets: Observations By IRIS, SDO, and Hinode and Magnetic Modeling With Data‐Driven
(2015-03-05) Cheung, Mark C.M.; De Pontieu, B.; Tarbell, Ted D.; Fu, Y.; Tian, Hui; Testa, Paola; Reeves, Kathy K.; Martínez-Sykora, J.; Boerner, B.; Wülser, J.P.; Lemen, James; Title, Alan M.; Hurlburt, Neal E.; Kleint, Lucia; Kankelborg, Charles; Jaeggli, Sarah; Golub, Leon; McKillop, Sean; Saar, Steven; Carlsson, Mats; Hansteen, Viggo H.
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.