Astronomy and Astrophysics – Astronomy
Scientific paper
May 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011spd....42.1104i&link_type=abstract
American Astronomical Society, SPD meeting #42, #11.04; Bulletin of the American Astronomical Society, Vol. 43, 2011
Astronomy and Astrophysics
Astronomy
Scientific paper
We report on the most prominent example of an above-the-loop-top hard X-ray source in the extensive solar flare data base of the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The limb flare of 2003 October 22 around 20UT shows a coronal source in the 40-100 keV range that is significantly above the thermal flare loop top, similar as seen in the famous Masuda flare. The above-the-loop-top source is only visible during one of the four hard X-ray peaks, highlighting the rare occurrence of above-the-loop-top sources that are equally bright as footpoint sources. The chromospheric emissions for the peak with above-the-loop-top source shows a single footpoint, with the second footpoint occulted. The relative timing between the above-the-loop-top and footpoint source shows that the coronal source peaks about 10 s before the footpoint source and decays during the time the footpoint source is most prominent.
Thanks to the good energy resolution of RHESSI, this is the first time to obtain accurate spectra of both above-the-loop-top and footpoint sources. Photon indices of the above-the-loop-top and the footpoint sources are 4.8±0.4 and 3.7±0.5, respectively. These difference of indices 1.1±0.6 suggests that these emission are from the same components of electrons through thin- and thick-target bremsstrahlung.
The large intensity of the above-the-loop-top source and the absence of thermal emission in the above-the-loop-top region suggests that the electrons within above-the-loop-top source are purely non-thermal. Based on this assumption, we estimate the number of the accelerated electrons and time scale. We discuss on the relation of the above-the-loop-top and footpoint sources and a possible model to explain this event.
Ishikawa Shin'nosuke
Krucker Sa"m
Lin Robert P.
Takahashi Tadayuki
No associations
LandOfFree
On the Relation of Above-the-loop-top and Footpoint Hard X-ray Sources in Solar Flares does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with On the Relation of Above-the-loop-top and Footpoint Hard X-ray Sources in Solar Flares, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Relation of Above-the-loop-top and Footpoint Hard X-ray Sources in Solar Flares will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-943593