Study of the 28 October 2003 and 20 January 2005 solar flares by means of 2.223MeV gamma-emission line

Troitskaia, E. V.; Arkhangelskaja, I. V.; Miroshnichenko, L. I.; Arkhangelsky, A. I.

doi:10.1016/j.asr.2008.11.015

Cited by 9 publications

(2 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The result of the second fitting model shows that the accelerated ion spectrum has an inclination to become hard with evolution. This characteristic was previously reported by Gan (2004) and Troitskaia et al (2009). Besides the time profiles of line flux and spectral index, we also derive the time evolution of the Compton scattered component.…”

Section: Application and Discussionsupporting

confidence: 77%

See 1 more Smart Citation

The effect of Compton scattering on gamma-ray spectra of the 2005 January 20 flare

Chen¹,

Gan²

2012

Res. Astron. Astrophys.

View full text Add to dashboard Cite

Gamma-ray spectroscopy provides a wealth of information about accelerated particles in solar flares, as well as the ambient medium with which these energetic particles interact. The neutron capture line (2.223 MeV), the strongest in the solar gamma-ray spectrum, forms in the deep atmosphere. The energy of these photons can be reduced via Compton scattering. With the fully relativistic GEANT4 toolkit, we have carried out Monte Carlo simulations of the transport of a neutron capture line in solar flares, and applied them to the flare that occurred on 2005 January 20 (X7.1/2B), one of the most powerful gamma-ray flares observed by RHESSI during the 23rd solar cycle. By comparing the fitting results of different models with and without Compton scattering of the neutron capture line, we find that when including the Compton scattering for the neutron capture line, the observed gamma-ray spectrum can be reproduced by a population of accelerated particles with a very hard spectrum (s ≤ 2.3). The Compton effect of a 2.223 MeV line on the spectra is therefore proven to be significant, which influences the time evolution of the neutron capture line flux as well. The study also suggests that the mean vertical depth for neutron capture in hydrogen for this event is about 8 g cm −2 .

show abstract

Section: Application and Discussionsupporting

confidence: 77%

“…The most effective neutrons for producing the 2.223 MeV line are those with energy below 50 MeV, which need to pass through a grammage of 10 g cm −2 for thermalization (Troitskaia et al 2009). Consequently, our result of 15 g cm −2 implies the existence of higher energy neutrons at the early phase.…”

Section: Application and Discussionmentioning

confidence: 65%