Hydrogen and helium isotope inner radiation belts in the Earth's magnetosphere

Inner radiation belt source of helium and heavy hydrogen isotopes

“…5(d). The difference of the experimental values for CRRES/ONR-604 and analytical curves could be due to the influence of radial diffusion near L $ 1.3 which has to be taken into account in the calculations (Pugacheva et al, 1998). Besides, the average value of the equator pitch-angle of trapped particles registered in CRRES experiment is higher $90°then one used in the presented calculations.…”

“…The calculation results are energy spectra and angular distributions of light nuclear isotopes in the inner radiation belt that may be used to develop helium inner radiation belt model and to evaluate their contribution to SEU rates. To calculate the fluxes at higher L-shell the additional study of diffusion processes is needed (Pugacheva et al, 1998). Although AP-8 and SAMPEX/ PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes (Heynderickx et al, 1999).…”

“…For L-shell less than 1.3 the atmospheric production of energetic secondary nuclei is balanced only by ionization energy loss in the atmosphere, as the radial diffusion is not significant at this region (Pugacheva et al, 1998). The intensity j of generated particles satisfies a continuity equation (Jentsch and Wibberenz, 1980):…”

“…If the pitch-angle of a generated particle lies outside the loss cone on the given geomagnetic shell this particle becomes trapped. It was shown (Galper et al, 2003;Pugacheva et al, 1998;Selesnick and Mewaldt, 1996) that such processes provide the main source of high-energy geomagnetically trapped 2 H, 3 H, 3 He and 4 He nuclei at L-shell < 1.3. This paper reports on the improved calculations of intensities of secondary light nuclei isotopes deduced from: the inner zone proton intensity obtained out of empirical models AP-8 and SAMPEX/PET PSB97; the atmosphere driftaveraged composition and densities from dynamic atmosphere model MSIS-90, and double-differential cross-sections for the various nuclear interaction processes extracted from GNASH nuclear model code.…”

Pitch angle distribution of trapped energetic protons and helium isotope nuclei measured along the Resurs-01 No. 4 LEO satellite

“…It is believed that this component results from the nuclear interaction of primary radiation and the upper atmosphere near the inner edge of the inner radiation belt (L<1.3) (Pugacheva et al, 1998;Selesnick and Mewaldt, 1996;Galper et al, 2003). In this region 3 He isotope is more abundant than 4 He, from energies more than 10 MeV/n.…”