ESTIMATION OF THE RECONNECTION ELECTRIC FIELD IN THE 2003 OCTOBER 29 X10 FLARE

Journal Article · Sun May 01 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/1/15· OSTI ID:21574661

Yang, Ya-Hui; Cheng, C Z ^[1]; Krucker, Saem ^[2]; Hsieh, Min-Shiu ^[3]

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1. Plasma and Space Science Center, National Cheng Kung University, Tainan 70101, Taiwan (China)
2. Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)
3. Institute of Space, Astrophysical and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China)

The electric field in the reconnecting current sheet of the 2003 October 29 X10 flare is estimated to be a few kV m{sup -1} in this study, based on the rate of change in the photospheric magnetic flux in the newly brightened areas of Transition Region and Coronal Explorer (TRACE) UV ribbons. For comparison, the motion speed of Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) hard X-ray (HXR) footpoints and the photospheric magnetic field strength are also used for the electric field calculation. This X10 flare event is selected due to its distinct two-phase HXR kernel motion, two arcade systems with different magnetic shear, and the high cadence and complete coverage of the TRACE 1600 A Michelson Doppler Imager (MDI) magnetogram and RHESSI HXR observations. We pay particular attention to the electric field characteristics in different flare phases, as well as the temporal correlation with the HXR emission and its power-law spectral index and the photospheric magnetic field strength. We found that in the early impulsive phase, the reconnection electric field peaks just before the HXR emission peaks and the energy spectrum hardens. The result is consistent with the scenario that more particles are accelerated to higher energies by larger reconnection electric fields and then precipitate into the lower chromosphere to produce stronger HXR emissions. Such a particle acceleration mechanism plays its most significant role in the impulsive phase of this flare. In addition, our results provide evidence that the highly sheared magnetic field lines are mapped to the magnetic reconnection diffusion region to produce a large reconnection electric field.

• OSTI ID: 21574661
• Journal Information: Astrophysical Journal, Vol. 732, Issue 1; Other Information: DOI: 10.1088/0004-637X/732/1/15; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CHROMOSPHERE
CORRELATIONS
DIFFUSION
ELECTRIC FIELDS
EMISSION
HARD X RADIATION
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETIC RECONNECTION
SOLAR FLARES
ATMOSPHERES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
RADIATIONS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR FLARES
X RADIATION