Invariants of the Spatial-Energy Structure and Modeling of the Earth's Ion Radiation Belts

Abstract

Abstract. The spatial-energy distributions of proton fluxes in the Earth's radiation belts (ERB) are well studied and the NASA averaged empirical models constructed for them (the latest versions are AP8 and AP9). These models are widely used in space research. However, for heavier ERB ions (helium, oxygen, etc.), much less measurements were made on satellites, especially in the energy range from tens to hundreds of MeV, and there are no sufficiently complete and reliable models for them. Meanwhile, such ions, although there are much smaller than protons, play a very important role in the physics of ERB, especially in their dynamics, as well as in solving problems of ensuring the safety of space flights. The data on such ions represent a rather fragmentary picture, in which there are significant white spots. Using the methods considered in this paper, these fragmentary data can be streamlined, linked to each other and get a regular picture that has a simple physical meaning. Spatial-energy distributions of the stationary fluxes of protons, helium ions and ions of the CNO group with energy from 100 keV to 200 MeV at L ~ 1–8 considered here on the data of the satellites for 1961–2017. It is found, that results of the measurements of the ion fluxes are arrange in certain regular patterns in the spaces {E, L} and {L, B/B0}. This effect connected with the existence of invariant parameters of these distributions of ion fluxes. These invariant parameters are very useful and necessary for constructing the ion models of the ERB. The physical mechanisms leading to formation spatial-energy structure of the ERB ion fluxes and the values of its invariant parameters discussed here. In the course of this work, solar-cyclic (11-year) variations in the distributions of helium and carbon-nitrogen-oxygen ions fluxes in the ERB studied for the first time. It shown that, as compared with such variations in the proton fluxes studied earlier, the amplitude of the variations of heavier ions is much larger and increases with increasing their mass.