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Title: RECONNECTION ELECTRIC FIELD AND HARDNESS OF X-RAY EMISSION OF SOLAR FLARES

Abstract

Magnetic reconnection is believed to be the prime mechanism that triggers solar flares and accelerates electrons up to energies of MeV. In the classical two-dimensional reconnection model, the separation motion of chromospheric ribbons, manifests the successive reconnection that takes place higher up in the corona. Meanwhile, downward traveling energetic electrons bombard the dense chromosphere and create hard X-ray (HXR) emissions, which provide a valuable diagnostic of electron acceleration. Analyses of ribbon dynamics and the HXR spectrum have been carried out separately. In this Letter, we report a study of the comparison of reconnection electric field measured from ribbon motion and hardness (spectral index) of X-ray emission derived from X-ray spectrum. Our survey of the maximum average reconnection electric field and the minimum overall spectral index for 13 two-ribbon flares shows that they are strongly anticorrelated. The former is also strongly correlated with flare magnitude measured using the peak flux of soft X-ray emissions. These provide strong support for electron acceleration models based on the electric field generated at reconnecting current sheet during flares.

Authors:
Publication Date:
OSTI Identifier:
21300760
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 696; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/696/1/L27; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-4357
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ACCELERATION; CHROMOSPHERE; ELECTRIC FIELDS; GAMMA RADIATION; HARD X RADIATION; MAGNETIC FIELDS; MAGNETIC RECONNECTION; SOFT X RADIATION; SOLAR FLARES; SUN; TAIL ELECTRONS; X-RAY SPECTRA

Citation Formats

Chang, Liu, and Wang Haimin. RECONNECTION ELECTRIC FIELD AND HARDNESS OF X-RAY EMISSION OF SOLAR FLARES. United States: N. p., 2009. Web. doi:10.1088/0004-637X/696/1/L27; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Chang, Liu, & Wang Haimin. RECONNECTION ELECTRIC FIELD AND HARDNESS OF X-RAY EMISSION OF SOLAR FLARES. United States. https://doi.org/10.1088/0004-637X/696/1/L27; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Chang, Liu, and Wang Haimin. 2009. "RECONNECTION ELECTRIC FIELD AND HARDNESS OF X-RAY EMISSION OF SOLAR FLARES". United States. https://doi.org/10.1088/0004-637X/696/1/L27; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21300760,
title = {RECONNECTION ELECTRIC FIELD AND HARDNESS OF X-RAY EMISSION OF SOLAR FLARES},
author = {Chang, Liu and Wang Haimin},
abstractNote = {Magnetic reconnection is believed to be the prime mechanism that triggers solar flares and accelerates electrons up to energies of MeV. In the classical two-dimensional reconnection model, the separation motion of chromospheric ribbons, manifests the successive reconnection that takes place higher up in the corona. Meanwhile, downward traveling energetic electrons bombard the dense chromosphere and create hard X-ray (HXR) emissions, which provide a valuable diagnostic of electron acceleration. Analyses of ribbon dynamics and the HXR spectrum have been carried out separately. In this Letter, we report a study of the comparison of reconnection electric field measured from ribbon motion and hardness (spectral index) of X-ray emission derived from X-ray spectrum. Our survey of the maximum average reconnection electric field and the minimum overall spectral index for 13 two-ribbon flares shows that they are strongly anticorrelated. The former is also strongly correlated with flare magnitude measured using the peak flux of soft X-ray emissions. These provide strong support for electron acceleration models based on the electric field generated at reconnecting current sheet during flares.},
doi = {10.1088/0004-637X/696/1/L27; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21300760}, journal = {Astrophysical Journal (Online)},
issn = {1538-4357},
number = 1,
volume = 696,
place = {United States},
year = {Fri May 01 00:00:00 EDT 2009},
month = {Fri May 01 00:00:00 EDT 2009}
}