Time delay between γ-ray lines and hard X-ray emissions during the 23 July 2002 solar flare interpreted by a trap plus precipitation model

Properties of Energetic Ions in the Solar Atmosphere from γ-Ray and Neutron Observations

“…However, these studies were performed using the time profile of the 4-8 MeV range as a proxy for the time profiles of the nuclear lines, and no images at X-rays or γ -rays were used as additional constraints on the model. A similar analysis was performed by Dauphin and Vilmer (2007) on the first γ -ray line event observed by RHESSI, SOL2002-07-23T00:35 (X4.8). Indeed, the analysis of the hard X-ray and γ -ray flux time evolution Share et al 2003a) showed that there is a slight delay between hard X-ray emission at 150 keV and γ -ray line emission.…”

“…The relative timing of prompt γ -ray line emissions and of hard X-rays was studied in this context by Hulot and collaborators. These models were again used to interpret the delays of the hard X-ray and γ -ray line emissions observed for two flares by ISEE-3 and SMM/GRS (Hulot et al 1992) and also applied to one of the γ -ray line flares observed with RHESSI (Dauphin and Vilmer 2007).…”

“…These time profiles are obtained from the spectroscopic analysis presented in Share et al (2003a). The spectral analysis is performed for successive time intervals of 20 s, and results in the fitting to observed count spectra of a model photon spectrum including a double power law for the bremsstrahlung continuum, a nuclear γ -ray Dauphin and Vilmer (2007), adapted from Share et al (2003a)) line function made of 15 narrow and broad Gaussians , a neutron-capture line , an α-4 He fusion line complex between ∼400 and 500 keV (Share et al 2003a), and the solar annihilation line at 511 keV and its positronium continuum. Figure 8-adapted from Share et al (2003a)-shows the results of this fit as a function of time: the bremsstrahlung flux at 150 keV and 1 MeV and the nuclear de-excitation line flux.…”

“…There is, however, no significant delay between the time profile at 150 keV and at 1 MeV. Dauphin and Vilmer (2007) investigated whether this delay could be reproduced by the trap-plus-precipitation model, given the additional constraint provided by the X-ray and γ -ray images. They found that the time profiles of both HXR and prompt γ -ray line fluxes could be reproduced (given that electrons and ions are injected and partially trapped in different coronal loop systems with slightly different characteristics discussed below) but they also found that the detailed X-ray and γ -ray time profiles could be well reproduced if the ratio of energetic electrons with respect to ions slightly varies from peak to peak during the flare.…”

Solar flares and energetic particles

“…The images for the 23 July 2002 event (figure 8a) would support such an interpretation of ions being injected in longer loops. For the same flare, the interpretation of time delays between g-ray lines and hard X-rays in the framework of trap plus precipitation models [38] on May 12, 2018 http://rsta.royalsocietypublishing.org/ Downloaded from displacements between the ion and electron emitting sources are two orders of magnitude too small. Another possibility raised by Litvinenko & Somov [39] is that electric-field acceleration would lead to separation of particles with opposite charge (see also [40]).…”