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Beam electrons as a source of H? 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 H? 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 H? 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 H? 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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