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Beam electrons as a source of Hα flare ribbons.

ABSTRACT: The observations of solar flare onsets show rapid increase of hard and soft X-rays, ultra-violet emission with large Doppler blue shifts associated with plasma upflows, and Hα hydrogen emission with red shifts up to 1-4 Å. Modern radiative hydrodynamic models account well for blue-shifted emission, but struggle to reproduce closely the red-shifted Hα lines. Here we present a joint hydrodynamic and radiative model showing that during the first seconds of beam injection the effects caused by beam electrons can reproduce Hα line profiles with large red-shifts closely matching those observed in a C1.5 flare by the Swedish Solar Telescope. The model also accounts closely for timing and magnitude of upward motion to the corona observed 29 s after the event onset in 171 Å by the Atmospheric Imaging Assembly/Solar Dynamics Observatory.

SUBMITTER: Druett M

PROVIDER: S-EPMC5490266 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Beam electrons as a source of Hα flare ribbons.

Druett Malcolm M Scullion Eamon E Zharkova Valentina V Matthews Sarah S Zharkov Sergei S Rouppe Van der Voort Luc L

Nature communications 20170627

The observations of solar flare onsets show rapid increase of hard and soft X-rays, ultra-violet emission with large Doppler blue shifts associated with plasma upflows, and Hα hydrogen emission with red shifts up to 1-4 Å. Modern radiative hydrodynamic models account well for blue-shifted emission, but struggle to reproduce closely the red-shifted Hα lines. Here we present a joint hydrodynamic and radiative model showing that during the first seconds of beam injection the effects caused by beam ...[more]

PMID: 28653670

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