안녕하세요. 우주과학과, 우주탐사학과 여러분.
이번 세미나는 12월 05일 오후 4시 30분, 천문대 영상실에서 있습니다.
서울대학교의 이정우 박사님께서 "Sigmoidal Hot Channel Detected Before Solar Eruptions"에 관한 강연을 해 주실 예정입니다.
강연은 한국어로 진행되며, 초록은 아래에 나타나있습니다. 세미나 참석을 원하시는 분은 세미나 시작 10분 전까지 입실해 주시기 바랍니다. 많은 참석 부탁드립니다. 감사합니다.
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Dear Colleagues,
There will be an Astronomy and Space Science seminar on 12/05, 4:30 PM, in the Auditorium, Kyung Hee University Astronomical Observatory.
Dr. Jeongwoo Lee of Seoul National University will give a presentation about "Sigmoidal Hot Channel Detected before Solar Eruptions".
The language of the seminar will be Korean and abstract is shown below.
You are asked to join the seminar five to ten minutes before it starts. Your attendance will greatly be appreciated.
Thank you.
* Abstract
We present an excellent piece of evidence that a flux rope can exist before a flare in the form of hot channel as found from the observations of the 2015 June 21 flare with the Solar Dynamics Observatory (SDO) and the Nobeyama Radioheliograph (NoRH). The SDO EUV images and the extrapolated nonlinear force-free field show that the impulsive flare results from the eruption of highly sheared low-lying flux and remains confined, but nevertheless spawns a vertical current sheet, where magnetic reconnection creates flare ribbons and loops and a sigmoidal hot channel. Until the second gradual flare, magnetic reconnection continues at a low rate and the sigmoid's elbows expand, while its center remains stationary under the erupted but still confined flux. The reconnection during and after the confined flare acts as tether-cutting reconnection, leading the flux rope to the point of instability and subsequent full eruption, seen as an accelerated rise of the entire hot channel and the formation of a fast halo coronal mass ejection (CME). The hot channel can only be interpreted as a magnetic flux rope, and this event is one of the clearest cases so far showing the existence of a flux rope prior to an eruption. It also demonstrates the contribution to flux rope formation by confined eruptions that trigger reconnection in a vertical current sheet under the erupted flux.
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