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Title: FINE STRUCTURE OF FLARE RIBBONS AND EVOLUTION OF ELECTRIC CURRENTS

Emission of solar flares across the electromagnetic spectrum is often observed in the form of two expanding ribbons. The standard flare model explains flare ribbons as footpoints of magnetic arcades, emitting due to interaction of energetic particles with the chromospheric plasma. However, the physics of this interaction and properties of the accelerated particles are still unknown. We present results of multiwavelength observations of the C2.1 flare of 2013 August 15, observed with the New Solar Telescope of the Big Bear Solar Observatory, and the Solar Dynamics Observatory, GOES, and Fermi spacecraft. The observations reveal previously unresolved sub-arcsecond structure of flare ribbons in regions of strong magnetic field consisting from numerous small-scale bright knots. We observe a red-blue asymmetry of H{sub α} flare ribbons with a width as small as ∼100 km. We discuss the relationship between the ribbons and vertical electric currents estimated from vector magnetograms, and show that Joule heating can be responsible for energization of H{sub α} knots in the ribbons.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [3]
  1. Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States)
  2. (Russian Federation)
  3. (United States)
Publication Date:
OSTI Identifier:
22365798
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 788; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; ELECTRIC CURRENTS; FINE STRUCTURE; JOULE HEATING; MAGNETIC FIELDS; PLASMA; SOLAR FLARES; SUN; TELESCOPES; VECTORS; WIDTH