2016/05/01 by Xin Cheng, X. Cheng, M. D. Ding · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Blueshift #Coronal mass ejection #Emission spectrum #Flux (metallurgy) #Geometry #Line (geometry) #Magnetic field #Magnetic flux #Magnetic reconnection #Materials science #Meteorology #Nuclear physics #Optics #Physics #Plasma #Solar and Space Plasma Dynamics #Solar flare #Solar wind #Spectral line #Spectrograph #Stellar, planetary, and galactic studies #Thermal #astro-ph.EP #astro-ph.SR #physics.space-ph
paper · pdf · doi:10.3847/2041-8205/823/1/l4
6 pages, 4 figures, accepted for publication in ApJ Letters
arxiv created 2016/05/01 · openalex publication_date 2016/05/12 · arxiv updated 2016/05/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ABSTRACT In this Letter, we present Interface Region Imaging Spectrograph Fe xxi 1354.08 Å forbidden line emission of two magnetic flux ropes (MFRs) that caused two fast coronal mass ejections with velocities of ≥1000 km s −1 and strong flares (X1.6 and M6.5) on 2014 September 10 and 2015 June 22, respectively. The extreme-ultraviolet images at the 131 and 94 Å passbands provided by the Atmospheric Imaging Assembly on board Solar Dynamics Observatory reveal that both MFRs initially appear as suspended hot channel-like structures. Interestingly, part of the MFRs is also visible in the Fe xxi 1354.08 forbidden line, even prior to the eruption, e.g., for the SOL2014-09-10 event. However, the line emission is very weak and that only appears at a few locations but not the whole structure of the MFRs. This implies that the MFRs could be comprised of different threads with different temperatures and densities, based on the fact that the formation of the Fe xxi forbidden line requires a critical temperature (∼11.5 MK) and density. Moreover, the line shows a non-thermal broadening and a blueshift in the early phase. It suggests that magnetic reconnection at that time has initiated; it not only heats the MFR and, at the same time, produces a non-thermal broadening of the Fe xxi line but also produces the poloidal flux, leading to the ascension of the MFRs.