Examining the optical intensity and magnetic field expansion factor in the open magnetic field regions associated with coronal holes. Issue Volume 15:Issue S354(2019) (June 2019)

• Record Type: Journal Article
• Authors: Lin, Chia-Hsien; Huang, Guan-Han; Lee, Lou-Chuang
• Editors: Kosovichev, Alexander; Strassmeier, Klaus; Jardine, Moira
• Is Part Of: Proceedings of the International Astronomical Union. Volume 15:Issue S354(2019)
• Page Start: 228
• Page End: 231
• Publication Date: 2019-06
• Subjects: magnetic fields, -- Sun: corona, -- Sun: magnetic fields, -- methods: statistical; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921320000393
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: Coronal holes can be identified as the darkest regions in EUV or soft X-ray images with predominantly unipolar magnetic fields (LIRs) or as the regions with open magnetic fields (OMF). Our study reveals that only 12% of OMF regions are coincident with LIRs. The aim of this study is to investigate the conditions that affect the EUV intensity of OMF regions. Our results indicate that the EUV intensity and the magnetic field expansion factor of the OMF regions are weakly positively correlated when plotted in logarithmic scale, and that the bright OMF regions are likely to locate inside or next to the regions with closed field lines. We empirically determined a linear relationship between the expansion factor and the EUV intensity. The relationship is demonstrated to improve the consistency from 12% to 23%. The results have been published in Astrophysical Journal (Huang et al. 2019 ).