Energetics and morphology of powerful impulsive solar flares

I. N. Sharykin, A. B. Struminsky, I. V. Zimovetz

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We have studied the energetics of two impulsive solar flares of X-ray class X1. 7 by assuming the electrons accelerated in several episodes of energy release to be the main source of plasma heating and reached conclusions about their morphology. The time profiles of the flare plasma temperature, emission measure, and their derivatives, and the intensity of nonthermal X-ray emission are compared; images of the X-ray sources and magnetograms of the flare region at key instants of time have been constructed. Based on a spectral analysis of the hard X-ray emission from RHESSI data and GOES observations of the soft X-ray emission, we have estimated the spatially integrated kinetic power of nonthermal electrons and the change in flare-plasma internal energy by taking into account the heat losses through thermal conduction and radiation and determined the parameters needed for thermal balance. We have established that the electrons accelerated at the beginning of the events with a relatively soft spectrum directly heat up the coronal part of the flare loops, with the increase in emission measure and hard X-ray emission from the chromosphere being negligible. The succeeding episodes of electron acceleration with a harder spectrum have virtually no effect on the temperature rise, but they lead to an increase in emission measure and hard X-ray emission from the footpoints of the flare loops.

Original languageEnglish (US)
Pages (from-to)672-680
Number of pages9
JournalAstronomy Letters
Volume38
Issue number10
DOIs
StatePublished - Oct 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • X-ray emission
  • chromospheric evaporation
  • nonthermal electrons
  • solar flares

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