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Title: Evidence of electron acceleration around the reconnection X-point in a solar flare

Particle acceleration is one of the most significant features that are ubiquitous among space and cosmic plasmas. It is most prominent during flares in the case of the Sun, with which huge amounts of electromagnetic radiation and high-energy particles are expelled into the interplanetary space through acceleration of plasma particles in the corona. Though it has been well understood that energies of flares are supplied by the mechanism called magnetic reconnection based on the observations in X-rays and EUV with space telescopes, where and how in the flaring magnetic field plasmas are accelerated has remained unknown due to the low plasma density in the flaring corona. We here report the first observational identification of the energetic non-thermal electrons around the point of the ongoing magnetic reconnection (X-point), with the location of the X-point identified by soft X-ray imagery and the localized presence of non-thermal electrons identified from imaging-spectroscopic data at two microwave frequencies. Considering the existence of the reconnection outflows that carries both plasma particles and magnetic fields out from the X-point, our identified non-thermal microwave emissions around the X-point indicate that the electrons are accelerated around the reconnection X-point. Additionally, the plasma around the X-point was also thermally heatedmore » up to 10 MK. The estimated reconnection rate of this event is ∼0.017.« less
Authors:
;  [1] ;  [2]
  1. National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)
  2. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan)
Publication Date:
OSTI Identifier:
22356446
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; AVAILABILITY; EMISSION; INTERPLANETARY SPACE; MAGNETIC FIELDS; MAGNETIC RECONNECTION; MICROWAVE RADIATION; PLASMA DENSITY; SOFT X RADIATION; SOLAR FLARES; SUN; TELESCOPES