Сборник с доклади от XXXIV Международен симпозиум | Page 287

1. INTRODUCTION

About 50 years ago, a new component of quiet-time cosmic ray flux with an unusual composition and energy spectrum was discovered, now known as Anomalous Cosmic Rays( ACRs) [ 4 ]. During the acceleration process, some of these ACRs, which are typically singly-ionized, lose additional electrons, resulting in the formation of more efficiently accelerated multiply-charged( MC) ions. Most ACRs with energies ≥30 MeV / nucleon are multiply charged [ 9 ], [ 11 ].

This paper explores the behavior of these multiply charged ACRs, particularly their penetration and ionization effects within the ionosphere-middle atmosphere system [ 15,10,2,13 ]. ACRs are thought to originate as singly-ionized particles [ 5 ], and studies have confirmed this for most ACRs with energies around 10 MeV / nucleon. However, data from the Solar Anomalous and Magnetospheric Explorer( SAMPEX) showed that at energies ≥25 MeV / nucleon, many ACRs have an ionic charge Q ≥ 2 [ 12 ]. This indicates that some ACRs are stripped of electrons during acceleration and gain energy in proportion to their charge, as proposed by Jokipii [ 9 ].

For example, oxygen ACRs can be accelerated to energies as high as ~ 100 MeV / nucleon, with approximately 20 % of oxygen ions being multiply charged. SAMPEX data also revealed that the ratio of Q = 1 to Q≥2 for nitrogen, oxygen, and neon crosses 50 % at an energy of ~ 360 MeV [ 12 ].

This study investigates the ionization effects of Multiply Charged ACRs( MCACRs) at the boundary between the ionosphere and middle atmosphere( 40-50 km), using the CORSIMA( COsmic Ray Spectra and Intensity in Middle Atmosphere) model [ 16 ]. ACR spectra are analyzed at various altitudes, utilizing satellite measurements of protons, helium, and oxygen nuclei. The findings show that MCACR influence extends to polar regions above 65 °-70 ° geomagnetic latitude, where ionization rates are comparable to those of Galactic Cosmic Rays( GCRs).

2. MODEL APPROXIMATIONS

In this study, we introduce a refined approach to calculate ionization losses due to Multiply Charged Anomalous Cosmic Rays( MCACRs) in the ionosphere and middle atmosphere. The ionization loss function, represented as dE / dh, depends on two primary factors: the particle ' s energy E and its charge Z. Mathematically, we express this dependence as:

( 1) dE � dh f( E, Z) where:

� E is the kinetic energy of the particle;

� Z is the charge of the particle, which directly affects the rate of energy loss during its interaction with atmospheric molecules.

To better approximate ionization losses across different energy ranges, we divide the energy spectrum into six characteristic intervals. These intervals allow us to apply specific formulations for dE / dh based on both energy and charge, enhancing the accuracy of the results. The intervals are described as follows:

( 2) � � �

�� � ��

By segmenting the energy range into these intervals, we can better capture the behavior of cosmic rays as they penetrate through the atmosphere. This refinement improves the accuracy of our predictions

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