Место издания:COSPAR 40th Scientific Assembly Moscow
Первая страница:D2.5-0106-14
Аннотация:Appreciable HXR/gamma-ray emissions in the 0.015-150 MeV energy range associated with the solar flare on 29 October 2003 (X10/3B) were observed at 20:41-20:58 with the SPR-N and SONG instruments onboard the CORONAS-F mission. Two time intervals were identified which showed major changes in the intensity of these emissions. To specify the details of the spectral changes with time, we fitted the SONG energy loss spectra with a three-component model of incident gamma-ray spectrum: (1) a power law in energy, assumed to be due to electron bremsstrahlung; (2) a broad continuum produced by nuclear de-excitation gamma-lines; and (3) a broad gamma-line generated from pion decay. We study the relationship between non-imaging observations, particularly between time of pion-decay emission onset and motions in this solar flare, using HXR foot points (FP) separation and flare shear temporal behavior presented by (Ji et al., 2008). In this work it was shown that significant FP converging and unshearing motion occurred during the first flare interval. During this interval the primary bremsstrahlung extended to tens of MeV and de-excitation gamma-lines dominated. During the second interval after 20:45 the FPs began to move apart. We found out that starting from 20:46, the gamma-emission spectrum revealed a feature attributed to pion-decay. It means that the effective acceleration of protons to energies above 300 MeV (pion-production threshold) occurred coincidently with a change of the flare magnetic structure. The maximum intensity of the pion-decay gamma emission was observed at 20:49 and proved to be 2.0∙10-4 photons cm-2 s-1 MeV-1 at 100 MeV. This flare was accompanied by GLE-66. Using the data of the world neutron monitor network, we found its onset as 20:59 which corresponds to a reasonable propagation time of protons with ~ 0.5-2 GeV energy on the assumption that proton acceleration began at 20:46.