2013/12/04 by Q. M. Zhang, H. S. Ji · 1 citation
Physics and Astronomy · #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/201322616
15 pages, 11 figures
arxiv created 2013/12/04 · arxiv updated 2015/06/18
We report our observations of a swirling flare-related EUV jet on 2011 October 15. We utilised the EUV observations from SDO/AIA. We extracted a wide slit along the jet axis and 12 thin slits across its axis to investigate the longitudinal motion and transverse rotation. We also used data from STEREO/EUVI to investigate the 3D structure of the jet. Gound-based Hα images provide a good opportunity to explore the relationship between the cool surge and hot jet. LOS magnetograms from SDO/HMI enable us to study the magnetic evolution of the flare/jet event. The onset of jet eruption coincided with the start time of C1.6 flare impulsive phase. The initial velocity and acceleration of the longitudinal motion were 254±10 km s-1 and -97±5 m s-2, respectively. The jet presented helical structure and transverse swirling motion at the beginning of its eruption. The counter-clockwise rotation slowed down from an average velocity of ∼122 km s-1 to ∼80 km s-1. The interwinding thick threads of the jet untwisted into multiple thin threads during the rotation that lasted for 1 cycle with a period of ∼7 min and an amplitude that increases from ∼3.2 Mm at the bottom to ∼11 Mm at the upper part. Afterwards, the curtain-like leading edge of the jet continued rising without rotation, leaving a dimming region behind before falling back to the solar surface. The appearance/disappearance of dimming corresponded to the longitudinal ascending/descending motions of jet. Cospatial Hα surge and EUV dimming imply that the dimming resulted from the absorption of hot EUV emission by cool surge. The flare/jet event was caused by continuous magnetic cancellation before the start of flare. The jet was associated with the open magnetic fields at the edge of AR 11314.