Nonpotentiality of chromospheric fibrils in NOAA active regions 11092 and 9661

Ju Jing, Yuan Yuan, Kevin Reardon, Thomas Wiegelmann, Yan Xu, Haimin Wang

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


In this paper, we present a method to automatically segment chromospheric fibrils from Hα observations and further identify their orientation. We assume that chromospheric fibrils are aligned with the magnetic field. By comparing the orientation of the fibrils with the azimuth of the embedding chromospheric magnetic field extrapolated from a potential field model, the shear angle, a measure of nonpotentiality, along the fibrils is readily deduced. Following this approach, we make a quantitative assessment of the nonpotentiality of fibrils in two NOAA active regions (ARs): (1) the relatively simple AR 11092, observed with very high resolution by Interferometric Bidimensional Spectrometer, and (2) a β-γ-δ AR 9661, observed with median resolution by Big Bear Solar Observatory before and after an X1.6 flare.

Original languageEnglish (US)
Article number67
JournalAstrophysical Journal
Issue number2
StatePublished - Oct 1 2011

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Sun: chromosphere
  • magnetic fields


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