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Title: OBSERVATIONAL EVIDENCE OF ELECTRON-DRIVEN EVAPORATION IN TWO SOLAR FLARES

We have explored the relationship between hard X-ray (HXR) emissions and Doppler velocities caused by the chromospheric evaporation in two X1.6 class solar flares on 2014 September 10 and October 22, respectively. Both events display double ribbons and the Interface Region Imaging Spectrograph slit is fixed on one of their ribbons from the flare onset. The explosive evaporations are detected in these two flares. The coronal line of Fe xxi 1354.09 Å shows blueshifts, but the chromospheric line of C i 1354.29 Å shows redshifts during the impulsive phase. The chromospheric evaporation tends to appear at the front of the flare ribbon. Both Fe xxi and C i display their Doppler velocities with an “increase-peak-decrease” pattern that is well related to the “rising-maximum-decay” phase of HXR emissions. Such anti-correlation between HXR emissions and Fe xxi Doppler shifts and correlation with C i Doppler shifts indicate the electron-driven evaporation in these two flares.
Authors:
; ;  [1]
  1. Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, CAS, Nanjing 210008 (China)
Publication Date:
OSTI Identifier:
22518727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 813; 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; CHROMOSPHERE; CORRELATIONS; DOPPLER EFFECT; EVAPORATION; GAMMA RADIATION; HARD X RADIATION; PHOTON EMISSION; RED SHIFT; SOLAR ELECTRONS; SOLAR FLARES; SUN; ULTRAVIOLET RADIATION; VELOCITY