2016/05/10 by Q. M. Zhang, D. Li, Z. J. Ning +3 · 77 citations
Physics and Astronomy · #Dust and Plasma Wave Phenomena #Evaporation #Explosive material #Flare #Ionosphere and magnetosphere dynamics #Line (geometry) #Magnetic field #Magnetic reconnection #Protein filament #Solar and Space Plasma Dynamics #Solar flare #astro-ph.SR
paper · pdf · doi:10.3847/0004-637x/827/1/27
published in The Astrophysical Journal 827(1), 27 (IOP Publishing) · 9 figures, accepted for publication by ApJ
arxiv created 2016/05/10 · openalex created_date 2016/06/24 · openalex publication_date 2016/08/03 · arxiv updated 2016/08/17 · openalex updated_date 2026/08/06
ABSTRACT In this paper, we report our multiwavelength observations of the C4.2 circular-ribbon flare in active region (AR) 12434 on 2015 October 16. The short-lived flare was associated with positive magnetic polarities and a negative polarity inside, as revealed by the photospheric line-of-sight magnetograms. Such a magnetic pattern is strongly indicative of a magnetic null point and spine-fan configuration in the corona. The flare was triggered by the eruption of a mini-filament residing in the AR, which produced the inner flare ribbon (IFR) and the southern part of a closed circular flare ribbon (CFR). When the eruptive filament reached the null point, it triggered null point magnetic reconnection with the ambient open field and generated the bright CFR and a blowout jet. Raster observations of the Interface Region Imaging Spectrograph show plasma upflow at speeds of 35–120 km s −1 in the Fe xxi λ 1354.09 line ( ) and downflow at speeds of 10–60 km s −1 in the Si iv λ 1393.77 line ( ) at certain locations of the CFR and IFR during the impulsive phase of the flare, indicating explosive chromospheric evaporation. Coincidence of the single hard X-ray source at 12–25 keV with the IFR and calculation based on the thick-target model suggest that the explosive evaporation was most probably driven by nonthermal electrons.