ULTRA-NARROW NEGATIVE FLARE FRONT OBSERVED in HELIUM-10830 USING the 1.6 m NEW SOLAR TELESCOPE

Yan Xu, Wenda Cao, Mingde Ding, Lucia Kleint, Jiangtao Su, Chang Liu, Haisheng Ji, Jongchul Chae, Ju Jing, Kyuhyoun Cho, Kyungsuk Cho, Dale Gary, Haimin Wang

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22 Scopus citations

Abstract

Solar flares are sudden flashes of brightness on the Sun and are often associated with coronal mass ejections and solar energetic particles that have adverse effects on the near-Earth environment. By definition, flares are usually referred to as bright features resulting from excess emission. Using the newly commissioned 1.6 m New Solar Telescope at Big Bear Solar Observatory, we show a striking "negative" flare with a narrow but unambiguous "dark" moving front observed in He i 10830 , which is as narrow as 340 km and is associated with distinct spectral characteristics in Hα and Mg ii lines. Theoretically, such negative contrast in He i 10830 can be produced under special circumstances by nonthermal electron collisions or photoionization followed by recombination. Our discovery, made possible due to unprecedented spatial resolution, confirms the presence of the required plasma conditions and provides unique information in understanding the energy release and radiative transfer in astronomical objects.

Original languageEnglish (US)
Article number89
JournalAstrophysical Journal
Volume819
Issue number2
DOIs
StatePublished - Mar 10 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Sun: UV radiation
  • Sun: activity
  • Sun: chromosphere
  • Sun: flares
  • Sun: infrared

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