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Title: ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS

Abstract

We investigate electron acceleration by electric fields induced by cascading reconnections in current sheets trailing coronal mass ejections via a test particle approach in the framework of the guiding-center approximation. Although the resistive electric field is much weaker than the inductive electric field, the electron acceleration is still dominated by the former. Anomalous resistivity η is switched on only in regions where the current carrier’s drift velocity is large enough. As a consequence, electron acceleration is very sensitive to the spatial distribution of the resistive electric fields, and electrons accelerated in different segments of the current sheet have different characteristics. Due to the geometry of the 2.5-dimensional electromagnetic fields and strong resistive electric field accelerations, accelerated high-energy electrons can be trapped in the corona, precipitating into the chromosphere or escaping into interplanetary space. The trapped and precipitating electrons can reach a few MeV within 1 s and have a very hard energy distribution. Spatial structure of the acceleration sites may also introduce breaks in the electron energy distribution. Most of the interplanetary electrons reach hundreds of keV with a softer distribution. To compare with observations of solar flares and electrons in solar energetic particle events, we derive hard X-ray spectramore » produced by the trapped and precipitating electrons, fluxes of the precipitating and interplanetary electrons, and electron spatial distributions.« less

Authors:
; ;  [1];
  1. Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
Publication Date:
OSTI Identifier:
22667521
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 827; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; CHROMOSPHERE; ELECTRIC FIELDS; ELECTROMAGNETIC FIELDS; ELECTRONS; ENERGY SPECTRA; GUIDING-CENTER APPROXIMATION; HARD X RADIATION; INTERPLANETARY SPACE; KEV RANGE; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; MASS; MEV RANGE; PLASMA; SOLAR CORONA; SOLAR FLARES; SPATIAL DISTRIBUTION; VELOCITY; X-RAY SPECTRA

Citation Formats

Zhou, X., Gan, W., Liu, S., Büchner, J., and Bárta, M., E-mail: zhou@mps.mpg.de, E-mail: liusm@pmo.ac.cn, E-mail: buechner@mps.mpg.de. ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS. United States: N. p., 2016. Web. doi:10.3847/0004-637X/827/2/94.
Zhou, X., Gan, W., Liu, S., Büchner, J., & Bárta, M., E-mail: zhou@mps.mpg.de, E-mail: liusm@pmo.ac.cn, E-mail: buechner@mps.mpg.de. ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS. United States. https://doi.org/10.3847/0004-637X/827/2/94
Zhou, X., Gan, W., Liu, S., Büchner, J., and Bárta, M., E-mail: zhou@mps.mpg.de, E-mail: liusm@pmo.ac.cn, E-mail: buechner@mps.mpg.de. 2016. "ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS". United States. https://doi.org/10.3847/0004-637X/827/2/94.
@article{osti_22667521,
title = {ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS},
author = {Zhou, X. and Gan, W. and Liu, S. and Büchner, J. and Bárta, M., E-mail: zhou@mps.mpg.de, E-mail: liusm@pmo.ac.cn, E-mail: buechner@mps.mpg.de},
abstractNote = {We investigate electron acceleration by electric fields induced by cascading reconnections in current sheets trailing coronal mass ejections via a test particle approach in the framework of the guiding-center approximation. Although the resistive electric field is much weaker than the inductive electric field, the electron acceleration is still dominated by the former. Anomalous resistivity η is switched on only in regions where the current carrier’s drift velocity is large enough. As a consequence, electron acceleration is very sensitive to the spatial distribution of the resistive electric fields, and electrons accelerated in different segments of the current sheet have different characteristics. Due to the geometry of the 2.5-dimensional electromagnetic fields and strong resistive electric field accelerations, accelerated high-energy electrons can be trapped in the corona, precipitating into the chromosphere or escaping into interplanetary space. The trapped and precipitating electrons can reach a few MeV within 1 s and have a very hard energy distribution. Spatial structure of the acceleration sites may also introduce breaks in the electron energy distribution. Most of the interplanetary electrons reach hundreds of keV with a softer distribution. To compare with observations of solar flares and electrons in solar energetic particle events, we derive hard X-ray spectra produced by the trapped and precipitating electrons, fluxes of the precipitating and interplanetary electrons, and electron spatial distributions.},
doi = {10.3847/0004-637X/827/2/94},
url = {https://www.osti.gov/biblio/22667521}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 827,
place = {United States},
year = {Sat Aug 20 00:00:00 EDT 2016},
month = {Sat Aug 20 00:00:00 EDT 2016}
}