2008/06/24 by Hui Tian, Werner Curdt, Eckart Marsch +1 · 49 citations
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Corona (planetary geology) #Electron #Electron temperature #Extreme ultraviolet #Extreme ultraviolet lithography #Field line #Magnetic field #Magnetic reconnection #Magnetohydrodynamics #Solar and Space Plasma Dynamics #Space Technology and Applications #Twist #astro-ph.SR
paper · pdf · doi:10.1086/590410
published in The Astrophysical Journal 681(2), L121-L124 (IOP Publishing) · 4 pages, 4 figures
openalex publication_date 2008/06/24 · arxiv created 2009/06/16 · arxiv updated 2011/02/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We performed a systematic study of the Doppler shifts and electron densities measured in an EUV bright point (hereafter BP) observed in more than 10 EUV lines with formation temperatures from log ( T /K) = 4.5 to 6.3. Those parts of a BP seen in transition region and coronal lines are defined as its cool and hot components, respectively. We find that the transition from cool to hot occurs at a temperature around log ( T /K) = 5.7. The two components of the BP reveal a totally different orientation and Doppler-shift pattern, which might result from a twist of the associated magnetic loop system. The analysis of magnetic field evolution and topology seems to favor a two-stage heating process, in which magnetic cancellation and separator reconnection are powering, respectively, the cool and hot components of the BP. We also found that the electron densities of both components of the BP are higher than those of the surrounding quiet Sun, and comparable to or smaller than active region densities.