• Title/Summary/Keyword: coronal

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2019 Total Solar Eclipse Expedition of KASI

  • Bong, Su-Chan;Yang, Heesu;Lee, Jae-Ok;Kim, Jinhyun;Jeon, Young-Beom;Jang, Bi-Ho;Seough, Jungjoon;Park, Young-Deuk
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.69.2-69.2
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    • 2020

  • Korea Astronomy and Space Science Institute (KASI) is developing a coronagraph to measure the coronal electron density, temperature, and speed utilizing spectral change of the K-corona around 400 nm. However, near UV light is more affected by atmospheric effect on the ground than visible light. For the total solar eclipse on July 2 2019, KASI organized an expedition team to test the possibility of the similar measurement scheme in the visible light. The observation site was in Las Flores, San Juan, Argentina. We built an imaging spectrograph using micro lenslet array and grism, named Coronal Integral Field Spectrograph (CorIFS). In addition, images of white light corona, wide field background, and all sky were taken with various camera settings. We present the preliminary results of the expedition.

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Triggering processes of two different eruptive events in active region 11283 using observation-based models

  • Kang, Jihye;Inoue, Satoshi;Moon, Yong-Jae
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.59.3-60
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    • 2021

  • An investigation of flare-producing magnetic structure is important for studying an initiation of eruptive events. In this study we select two different eruptive events, M5.3 and X1.2 flares in active region (AR) 11283. Both events occur in the same AR, but brightenings of flare ribbons, seen in EUV images, are different shapes. In order to understand triggering process of eruptive flares, we reconstruct coronal magnetic fields using two observation-based models: a nonlinear force-free field (NLFFF) extrapolation model and a magnetohydodynamic (MHD) one. The NLFFFs show that sheared arcades and overlying fan-spine configurations are found in both cases, but the distributions of magnetic twist are weaker before the M5.3 flare than before the X1.2 flare. The MHD model is to explore the temporal evolution of coronal magnetic structures by considering the NLFFF with an anomalous resistivity as an initial condition. We discuss possible processes of two eruptive events using the MHD as well as the NLFFF model results.

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