Diagnostics of Ellerman bombs with high-resolution spectral data

Zhen Li, Cheng Fang, Yang Guo, Peng Fei Chen, Zhi Xu, Wenda Cao

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Ellerman bombs (EBs) are tiny brightenings often observed near sunspots. The most impressive characteristic of EB spectra is the two emission bumps in both wings of the H and Ca II 8542Å lines. High-resolution spectral data of three small EBs were obtained on 2013 June 6 with the largest solar telescope, the 1.6 m New Solar Telescope at the Big Bear Solar Observatory. The characteristics of these EBs are analyzed. The sizes of the EBs are in the range of 0.3′ - 0.8′ and their durations are only 3-5 min. Our semi-empirical atmospheric models indicate that the heating occurs around the temperature minimum region with a temperature increase of 2700-3000 K, which is surprisingly higher than previously thought. The radiative and kinetic energies are estimated to be as high as 51025 - 3.01026 erg despite the small size of these EBs. Observations of the magnetic field show that the EBs just appeared in a parasitic region with mixed polarities and were accompanied by mass motions. Nonlinear force-free field extrapolation reveals that the three EBs are connected with a series of magnetic field lines associated with bald patches, which strongly implies that these EBs should be produced by magnetic reconnection in the solar lower atmosphere. According to the lightcurves and the estimated magnetic reconnection rate, we propose that there is a three phase process in EBs: pre-heating, flaring and cooling phases.

Original languageEnglish (US)
Pages (from-to)1513-1524
Number of pages12
JournalResearch in Astronomy and Astrophysics
Volume15
Issue number9
DOIs
StatePublished - Sep 1 2015

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Sun: chromosphere
  • Sun: photosphere
  • line profiles
  • magnetic reconnection

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