Chromospheric signatures of small-scale flux emergence as observed with New Solar Telescope and Hinode instruments

Vasyl Yurchyshyn, P. R. Goode, V. I. Abramenko, J. Chae, Wenda Cao, A. Andic, Kwangsu Ahn

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

With the ever-increasing influx of high-resolution images of the solar surface obtained at a multitude of wavelengths, various processes occurring at small spatial scales have become a greater focus of our attention. Complex smallscale magnetic fields have been reported that appear to have enough stored energy to heat the chromosphere. While significant progress has been made in understanding small-scale phenomena, many specifics remain elusive. We present here a detailed study of a single event of disappearance of a magnetic dipole and associated chromospheric activity. Based on New Solar Telescope Hα data and Hinode photospheric line-of-sight magnetograms and Ca II H images, we report the following. (1) Our analysis indicates that even very small dipoles (elements separated by about 0′′.5 or less) may reach the chromosphere and trigger non-negligible chromospheric activity. (2) Careful consideration of the magnetic environment where the new flux is deposited may shed light on the details of magnetic flux removal from the solar surface. We argue that the apparent collision and disappearance of two opposite polarity elements may not necessarily indicate their cancellation (i.e., reconnection, emergence of a "U" tube, or submergence of Ω loops). In our case, the magnetic dipole disappeared by reconnecting with overlying large-scale inclined plage fields. (3) Bright points (BPs) seen in off-band Hα images are very well correlated with the Ca II H BPs, which in turn are cospatial with G-band BPs. We further speculate that, in general, Hα BPs are expected to be cospatial with photospheric BPs; however, a direct comparison is needed to refine their relationship.

Original languageEnglish (US)
Pages (from-to)1970-1976
Number of pages7
JournalAstrophysical Journal
Volume722
Issue number2
DOIs
StatePublished - Oct 20 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Sun: chromosphere
  • Sun: faculae, plages
  • Sun: magnetic topology
  • Sun: photosphere
  • Sun: surface magnetism

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