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arXiv · 1511.07757

Correlation of hard X-ray and white light emission in solar flares

Matej Kuhar·Säm Krucker·Juan Carlos Martínez Oliveros·Marina Battaglia·Lucia Kleint·Diego Casadei·Hugh S. Hudson
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Abstract

A statistical study of the correlation between hard X-ray and white light emission in solar flares is performed in order to search for a link between flare-accelerated electrons and white light formation. We analyze 43 flares spanning GOES classes M and X using observations from RHESSI (Reuven Ramaty High Energy Solar Spectroscopic Imager) and HMI (Helioseismic and Magnetic Imager). We calculate X-ray fluxes at 30 keV and white light fluxes at 6173 Å summed over the hard X-ray flare ribbons with an integration time of 45 seconds around the peak hard-X ray time. We find a good correlation between hard X-ray fluxes and excess white light fluxes, with a highest correlation coefficient of 0.68 for photons with energy of 30 keV. Assuming the thick target model, a similar correlation is found between the deposited power by flare-accelerated electrons and the white light fluxes. The correlation coefficient is found to be largest for energy deposition by electrons above ~50 keV. At higher electron energies the correlation decreases gradually while a rapid decrease is seen if the energy provided by low-energy electrons is added. This suggests that flare-accelerated electrons of energy ~50 keV are the main source for white light production.

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Matej Kuhar, Säm Krucker, Juan Carlos Martínez Oliveros, Marina Battaglia, Lucia Kleint, Diego Casadei, Hugh S. Hudson. 2015-11-24. Correlation of hard X-ray and white light emission in solar flares. https://doi.org/10.3847/0004-637x%2F816%2F1%2F6

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