High-Energy Emissions Observed in the Impulsive Phase of the 2001 August 25 Eruptive Flareстатья
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 26 июня 2024 г.
Аннотация:We analyze here the impulsive phase of the 2001 August 25 eruptive flare (X5.3, S21, E38) in order to reveal the link of the time evolution of the magnetic-field reconnection rate ϕ(t) ˙ with the energy-release process, as quantified by electron and proton acceleration to high energies. Hard X-rays and γ-rays from 150 keV to 100 MeV were observed by the SONG (SOlar Neutrons and Gamma) detector onboard the CORONAS-F (Complex ORbital ObservatioNs of the Active Sun) mission. The soft X-ray derivative dISXR/dt was used as a proxy for the flare energy release that revealed itself as a sequence of acceleration pulses. The reconnection rate ϕ(t) ˙ was calculated previously from flare-ribbon observations in EUV and coaligned magnetic-field maps. The γ-ray emission spectra were obtained from SONG data. All spectra contain both bremsstrahlung and γ-ray lines. The bremsstrahlung spectrum extends to tens of MeV. The pion-decay gamma-ray emission, being a manifestation of proton acceleration to subrelativistic energies, appeared for the first time in the time interval of the ϕ(t) ˙ maximum. This maximum was ahead of the maxima of dISXR/dt as well as of all other emissions by about one minute. Proton acceleration to subrelativistic energies is confirmed by detection of solar neutrons by SONG and the Chacaltaya neutron monitor