Kappa distribution and hard X-ray emission of solar flares

Abstract

We investigate whether the so-called kappa distribution, often used to fit electron distributions detected in-situ in the solar wind, can describe electrons producing the hard X-ray emission in solar flares. Using Ramaty High Energy Solar Spectroscopic imager (RHESSI) flare data we fit spatially- and feature-integrated spectra, assuming kappa distribution for the mean electron flux spectrum. We show that a single kappa distribution generally cannot describe spatially integrated X-ray emission composed of both footpoint and coronal sources. In contrast, the kappa distribution is consistent with mean electron spectra producing hard X-ray emission in some coronal sources.

4 pages, 4 figures, changed content, accepted to A&A

References in corpus (2)

• Relations between concurrent hard X-ray sources in solar flares
• Low-energy cutoffs in electron spectra of solar flares: statistical survey

Cited by in corpus (19)

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• Hard X-Ray Emission from Partially Occulted Solar Flares: RHESSI Observations in Two Solar Cycles
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