2007/06/30 by P. R. Young, Peter R. Young, G. Del Zanna +6 · 6 citations
Chemistry · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Atomic physics #Chemistry #Emission spectrum #Line (geometry) #Optics #Physics #Recombination #Solar and Space Plasma Dynamics #Spectral line #Stellar, planetary, and galactic studies #Wavelength #astro-ph
paper · pdf · doi:10.1093/pasj/59.sp3.s727
11 pages, 9 figures, submitted to PASJ Hinode first results issue
arxiv created 2007/08/14 · openalex publication_date 2007/11/30 · arxiv updated 2015/05/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Two types of solar active region feature prominent at transition region temperatures are identified in Hinode/EIS data of AR 10938 taken on 2007 January 20. The footpoints of 1 MK TRACE loops are shown to emit strongly in emission lines formed at log~T= 5.4–5.8, allowing the temperature increase along the footpoints to be clearly seen. A density diagnostic of Mg VII yields the density in the footpoints, with one loop showing a decrease from 3× 109 cm-3 at the base to 1.5×109 cm-3 at a projected height of 20 Mm. The second feature is a compact active region transition region brightening which is particularly intense in O V emission (log~T= 5.4) but also has a signature at temperatures up to log~T= 6.3. The Mg VII diagnostic gives a density of 4× 1010 cm-3, and emission lines of Mg VI and Mg VII show line profiles broadened by 50 km s-1 and wings extending beyond ±200 km s-1. Continuum emission in the short wavelength band is also found to be enhanced, and is suggested to be free-bound emission from recombination onto He+.