RHESSI Observations of Long-Duration Flares With Long-Lasting X-ray Loop-Top Sources

Abstract

Context: The Yohkoh/HXT observations of Long Duration Events (LDEs) showed that the HXR emission (14-23 keV) is present for tens of minutes after flare maximum. Hence, some heating process is expected to exist during that time. The better energy resolution of RHESSI compared to HXT allow us to analyse LDEs in more comprehensive way. Aims: We selected three LDEs observed by RHESSI to answer the questions how long HXR emission can be present, where it is emitted, what is its nature and how much energy should be released to sustain the emission. Methods: We used RHESSI data to reconstruct images of the selected flares with an energy resolution as good as 1 keV. Next we estimated physical parameters of HXR sources through imaging spectroscopy. The physical parameters obtained were then used to calculate the energy balance of the observed sources. Results: We found that HXR thermal emission can be present for many hours after LDE flare maximum. The emission comes from large and hot loop-top sources. The total energy that must be released to sustain the emission of the sources is as high as 10^31 erg.

11 pages, 15 figures; to be published in Astronomy and Astrophysics

References in corpus (4)

• Double Coronal Hard and Soft X-ray Source Observed by RHESSI: Evidence for Magnetic Reconnection and Particle Acceleration in Solar Flares
• RHESSI Line and Continuum Observations of Super-hot Flare Plasma
• Acceleration, magnetic fluctuations and cross-field transport of energetic electrons in a solar flare loop
• X-ray emission from the base of a current sheet in the wake of a CME

Cited by in corpus (4)

• Quasi-periodic pulsations in a solar flare with an unusual phase shift
• Temporal variations of X-ray solar flare loops: length, corpulence, position, temperature, plasma pressure and spectra
• Coronal Mass Ejections Associated with Slow Long Duration Flares
• Plasma dynamics in the flaring loop observed by RHESSI