Exploring the connection between coronal and footpoint sources in a thin-thick target solar flare model

Abstract

Context: Hard X-ray emission of coronal sources in solar flares has been observed and studied since its discovery in Yohkoh observations. Several models have been proposed to explain the physical mechanisms causing this emission and the relations between those sources and simultaneously observed footpoint sources. Aims: We investigate and test one of the models (intermediate thin-thick target model) developed on the basis of Yohkoh observations. The model makes precise predictions on the shape of coronal and footpoint spectra and the relations between them, that can be tested with new instruments such as RHESSI. Methods: RHESSI observations of well observed events are studied in imaging and spectroscopy and compared to the predictions from the intermediate thin-thick target model. Results: The results indicate that such a simple model cannot account for the observed relations between the non-thermal spectra of coronal and footpoint sources. Including non-collisional energy loss of the electrons in the flare loop due to an electric field can solve most of the inconsistencies.

References in corpus (1)

• Relations between concurrent hard X-ray sources in solar flares

Cited by in corpus (13)

• Implications of X-ray Observations for Electron Acceleration and Propagation in Solar Flares
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• The Low-High-Low Trend of Type III Radio Burst Starting Frequencies and Solar Flare Hard X-rays
• Observational evidence for return currents in solar flare loops
• Positions and sizes of X-ray solar flare sources
• The spectral difference between solar flare HXR coronal and footpoint sources due to wave-particle interactions
• YOHKOH remnants: partially occulted flares in hard X-rays
• Effect of turbulent density-fluctuations on wave-particle interactions and solar flare X-ray spectra
• Thermalisation and hard X-ray bremsstrahlung efficiency of self-interacting solar flare fast electrons
• A Revisit of the Masuda Flare
• Ramaty High Energy Solar Spectroscopic Imager (RHESSI)