Ionization losses of the Earth’s radiation belt protons according to the radial diffusion theory

Using modern models of the plasmasphere and exosphere, radial profiles of the rates of ionization losses of protons with μ = 0.3–10 keV/nT (μ is the first adiabatic invariant) of the Earth’s radiation belts (ERBs) have been constructed. To calculate Coulomb losses of protons, we used the ISEE-1 satellite data at L = 3–9 and CRRES satellite data at L ≤ 3 (L is the McIlwain parameter). The relation of contributions of Coulomb losses and charge exchange in the rate of ionization losses of protons has been considered. We have discovered the effect of subtracting Coulomb losses from charge exchange of ERB protons for small μ and L, which can imitate a local particle source. It has been demonstrated that, with decreasing L, the rate of ionization losses of ERB protons decreases as a whole. The radial dependence of this rate only has a negative gradient in the narrow range (ΔL ~ 0.5) in the region of the plasmapause and only for protons with μ > 1.2 keV/nT.     

Storm deviations of the geomagnetic trap core from dipole configuration deduced from data on relativistic electrons

Satellite data on the position of maximum L _m of the belt of relativistic electrons during strong storms, obtained at low altitudes (∼500 km) and at high altitudes (near the geomagnetic equator plane), are compared (L is the McIlwain parameter). Both at low and high altitudes the maximum of the storm belt of relativistic electrons is formed on the outer edge of the ring current. It is shown that the geomagnetic field can substantially deviate from dipole configuration not only at the geomagnetic trap periphery, but at its core as well (at L ∼ 2.5–3.5), and these deviations are nonlinear. Simultaneous measurements of the fluxes of relativistic electrons at low and high altitudes can serve for estimation of the real shape of magnetic field lines at L < 4 during geomagnetic disturbances.     

An Empirical Model of the Radiation Belt of Helium Nuclei

Based on satellite data, we present the results of modeling the spatial and energy distributions of integral fluxes of He nuclei (α particles) with E > 1, 2, 4, and 7 MeV at L = 1.1–6.6 in a broad range of B/B ₀ (E is the kinetic energy of particles, L is the drift shell parameter, and B/B ₀ is the magnetic field ratio). Some ways of practically applying the model are considered. The results of calculation of α-particle fluxes for a circular orbit with a height of 300 km and an inclination of 50° are presented.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 4, 2005, pp. 243–247.Original Russian Text Copyright © 2005 by Getselev, Sosnovets, Kovtyukh, Dmitriev, Podzolko, Vlasova, Reizman.     

Ion Composition of the Earth’s Radiation Belts in the Range from 100 keV to $100\mbox{ MeV}/\mbox{nucleon}$: Fifty Years of Research

Spatial, energy and angular distributions of ion fluxes in the Earth’s radiation belts (ERB) near the equatorial plane, at middle geomagnetic latitudes and at low altitudes are systematically reviewed herein. Distributions of all main ion components, from protons to Fe (including hydrogen and helium isotopes), and their variations under the action of solar and geomagnetic activity are considered. For ions with \(Z\geq 2\) and especially for ions with \(Z \geq 9\), these variations are much more than for protons, and these have no direct connection with the intensity of magnetic storms (\(Z\) is the charge of the atomic nucleus with respect to the charge of the proton). The main physical mechanisms for the generation of ion fluxes in the ERB and the losses of these ions are considered. Solar wind, Solar Cosmic Rays (SCR), Galactic Cosmic Rays (GCR), and Anomalous component of Cosmic Rays (ACR) as sources of ions in the ERB are considered.     

Observation of the Near Plasma Sheet,Ring Current,and Energetic Electrons from Radiation Belts at a Geosynchronous Orbit,March 11–25, 1992

The dynamics of near plasma sheet electrons and ions (E 0.1–12.4 keV), ring current protons (E _i 41–133 keV), and energetic electrons from the Earth's radiation belts (E _e 97–1010 keV) is considered using the data from the Gorizont-34and Gorizont-35geosynchronous satellites from March 11–25, 1992. Peculiarities of this period are a long (more than 4 days) interval of the northward interplanetary magnetic field (B _z> 0) and a high-speed stream of the solar wind with an enhanced particle density. The SC and compression of the magnetosphere to the geosynchronous orbit (GMC) preceded this interval. Under quiet and moderately disturbed geomagnetic conditions and under a prolonged northward interplanetary magnetic field, we observed a significant decrease of fluxes and softening of spectra of the electron component of plasma in the energy ranges of 0.1–12.4 keV and 97–1010 keV, and of the ion component of plasma at energies of 0.1–4 keV, while the intensity of 5–12.4 keV ion fluxes increases by about one order of magnitude. The peculiarities of distributions of energetic particle fluxes observed in the period under consideration can be associated with significant variations of the convection conditions and a decreased or fully suppressed injection of energetic electrons into the geosynchronous orbit region.