Earth's radiation belts' ions: patterns of the spatial-energy structure and its solar-cyclic variations

• Main Author: A. S. Kovtyukh
• Format: Article
• Language: English
• Published: Copernicus Publications 2020-01-01
• Series: Annales Geophysicae
• Online Access: https://www.ann-geophys.net/38/137/2020/angeo-38-137-2020.pdf
• ISSN: 0992-7689; 1432-0576

<p>Spatial-energy distributions of the stationary fluxes of protons, helium, and ions of the carbon–nitrogen–oxygen (CNO) group, with energy from <span class="inline-formula"><i>E</i></span> <span class="inline-formula">∼100</span>&thinsp;keV to 200&thinsp;MeV, in the Earth's radiation belts (ERBs), at <span class="inline-formula"><i>L</i>∼1</span>–8, are considered here using data from satellites during the period from 1961 to 2017. It has been found that the results of these measurements line up in the <span class="inline-formula"><i>{</i><i>E</i>,<i>L</i><i>}</i></span> space, following some regular patterns. The ion ERB shows a single intensity peak that moves toward Earth with increasing energy and decreasing ion mass. Solar-cyclic (11-year) variations in the distributions of protons, helium, and the CNO group ion fluxes in the ERB are studied. In the inner regions of the ERB, it has been observed that fluxes decrease with increasing solar activity and that the solar-cyclic variations of fluxes of <span class="inline-formula"><i>Z</i>≥2</span> ions are much greater than those for protons; moreover, it seems that they increase with increasing atomic number <span class="inline-formula"><i>Z</i></span>. It is suggested that heavier ion intensities peak further from the Earth and vary more over the solar cycle, as they have more strong ionization losses. These results also indicate that the coefficient <span class="inline-formula"><i>D</i>_LL</span> of the radial diffusion of the ERB ions changes much less than the ionization loss rates of ions with <span class="inline-formula"><i>Z</i>≥2</span> due to variations in the level of solar activity.</p>