論文

査読有り
2020年5月

On the Ratios of Si IV Lines (lambda 1394/lambda 1403) in an Emerging Flux Region

ASTROPHYSICAL JOURNAL
  • Durgesh Tripathi
  • ,
  • V. N. Nived
  • ,
  • Hiroaki Isobe
  • ,
  • G. Gerard Doyle

894
2
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.3847/1538-4357/ab8558
出版者・発行元
IOP PUBLISHING LTD

The resonance lines of Si iv formed at lambda 1394 and 1403 A are the most critical for the diagnostics of the solar transition region in the observations of the Interface Region Imaging Spectrograph (IRIS). Studying the intensity ratios of these lines (1394 A/1403 A), which under optically thin conditions is predicted to be two, helps us to diagnose the optical thickness of the plasma being observed. Here we study the evolution of the distribution of intensity ratios in 31 IRIS rasters recorded for four days during the emergence of an active region. We found that during the early phase of the development, the majority of the pixels show intensity ratios smaller than two. However, as the active region evolves, more and more pixels show the ratios closer to two. Besides, there are a substantial number of pixels with ratio values larger than 2. At the evolved stage of the active region, the pixels with ratios smaller than two were located on the periphery, whereas those with values larger than 2 were in the core. However, for quiet Sun regions, the obtained intensity ratios were close to two irrespective of the location on the disk. Our findings suggest that the Si iv lines observed in active regions are affected by the opacity during the early phase of the flux emergence. The results obtained here could have important implications for the modeling of the solar atmosphere, including the initial stage of the emergence of an active region as well as the quiet Sun.

Web of Science ® 被引用回数 : 3

リンク情報
DOI
https://doi.org/10.3847/1538-4357/ab8558
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000536089400001&DestApp=WOS_CPL
ID情報
  • DOI : 10.3847/1538-4357/ab8558
  • ISSN : 0004-637X
  • eISSN : 1538-4357
  • Web of Science ID : WOS:000536089400001

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