caa a22 4500 445346590 CHVBK 20180317142830.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s11207-010-9688-z doi (NATIONALLICENCE)springer-10.1007/s11207-010-9688-z A Revisit of the Masuda Flare [Elektronische Daten] [Rui Liu, Yan Xu, Haimin Wang] We revisit the flare that occurred on 13 January 1992, which is now universally termed the "Masuda flare”. The new analysis is motivated not just by its uniqueness despite the increasing number of coronal observations in hard X-rays, but also by the improvement of Yohkoh hard X-ray image processing, which was achieved after the intensive investigations on this celebrated event. Using an uncertainty analysis, we show that the hard X-ray coronal source is located closer to the soft X-ray loop by about 5000 km (or 7 arcsec) in the re-calibrated Hard X-ray Telescope (HXT) images than in the original ones. Specifically, the centroid of the M1-band (23 - 33keV) coronal source is above the maximum brightness of the Soft X-ray Telescope (SXT) loop by 5000±1000 km (9600 km in the original data) and above the apex of the SXT loop represented by the 30% brightness contour by 2000±1000 km (∼ 7000km in the original data). The change is obviously significant, because most coronal sources are above the thermal loop by less than 6 arcsec. We suggest that this change may account for the discrepancy in the literature, i.e., the spectrum of the coronal emission was reported to be extremely hard below ∼ 20keV in the pre-calibration investigations, whereas it was reported to be considerably softer in the literature after the re-calibration done by Sato, Kosugi, and Makishima (Pub. Astron. Soc. Japan 51, 127, 1999). Still, the coronal spectrum is flatter at lower energies than at higher energies, due to the lack of a similar, co-spatial source in the L-band (14 - 23keV), for which a convincing explanation is absent. Springer Science+Business Media B.V., 2010 Flares, dynamics nationallicence Flares, energetic particles nationallicence Flares, impulsive phase nationallicence Flares, spectrum nationallicence Liu Rui Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, 07102, Newark, NJ, USA aut Xu Yan Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, 07102, Newark, NJ, USA aut Wang Haimin Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, 07102, Newark, NJ, USA aut Solar Physics Springer Netherlands 269/1(2011-03-01), 67-82 0038-0938 269:1<67 2011 269 11207 https://doi.org/10.1007/s11207-010-9688-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-010-9688-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Liu Rui Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, 07102, Newark, NJ, USA aut NATIONALLICENCE 700 1- Xu Yan Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, 07102, Newark, NJ, USA aut NATIONALLICENCE 700 1- Wang Haimin Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, 07102, Newark, NJ, USA aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 269/1(2011-03-01), 67-82 0038-0938 269:1<67 2011 269 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer