Numerous energetic electron precipitation events were recorded since 1963 in the atmosphere at polar latitudes in the course of regular measurements of charged particle fluxes in the Earth's ...atmosphere being performed by the Lebedev Physical Institute. The experimental data obtained represent the only uniform database in the world on electron precipitation events recorded directly in the atmosphere well below satellite orbits. The precipitating electrons are absorbed in the upper atmosphere. However, they generate X‐rays that can penetrate deep into the atmosphere sometimes down to altitudes of 20–35 km accessible to balloon measurements. These experimental data allow studying energy, temporal and spatial characteristics of electron precipitation events. In particular, based on PLANETOCOSMICS/GEANT4 we developed a method for evaluating the energy spectra of the primary flux of precipitating electrons. This method was used for evaluation of primary spectra of precipitating electrons assuming exponential energy distribution of incident electrons. Now, for the development of the method, we present the possibility of determining the energy spectra of electrons in the power‐law form, using new software RUSCOSMICS code. This new method, based on the GEANT4 software, makes it possible to describe the transport of precipitating electrons in the atmosphere taking into account the evolution of the energy and pitch‐angle distributions of electrons and X‐ray photons.
Key Points
We developed a new method of evaluation of energy spectra of primary flux of precipitating electrons
Knowledge of the spectrum is important for understanding the processes of acceleration and loss of electrons in the outer radiation belt
The method describes evolution of the energy and pitch‐angle distributions of electrons and X‐ray photons in the atmosphere
Regular measurements of fluxes of charged particles in the Earth’s atmosphere conducted by the Lebedev Physical Institute (LPI) made it possible to register since 1963 more than 500 cases of ...precipitation of energetic electrons in the northern polar latitudes. The obtained experimental data represent the world’s only database on the precipitation of electrons registered directly in the Earth’s atmosphere. Primary precipitating electrons are absorbed in the upper layers of the atmosphere. However, the fluxes of secondary photons generated by them can penetrate deep into the atmosphere, sometimes to heights of ~20 km, which are accessible for balloon measurements by the Lebedev Physical Institute. This paper presents a new technique for reconstructing the energy spectrum of precipitating electrons developed on the basis of the Monte Carlo simulation of the processes of electron propagation in the atmosphere. The applicability of the technique to the accumulated experimental data is shown, and new results are presented for individual events recorded in the atmosphere.
In this paper, we examine the features of RSDN-20 signal propagation in a high-latitude Earth–ionosphere waveguide during solar proton events, using computational experiment methods. We have analyzed ...two proton ground-level enhancement (GLE) events of December 13, 2006 (GLE70) and September 10, 2017 (GLE72). Electron density profiles were constructed using the Global Dynamic Model of Ionosphere (GDMI) and the RUSCOSMICS model, developed at PGI. We present estimated phase and amplitude changes in RSDN-20 signals during precipitation of high-energy protons in the high-latitude region of the Earth–ionosphere waveguide. From the results of computational experiments and the analysis of the electromagnetic signal attenuation based on analytical Maxwell’s equation system solution in magnetized ionospheric plasma, we have found a pattern in the signal attenuation frequency dependence associated simultaneously with the signal reflection height, electron density profiles, and the collision frequency of electrons with neutral particles and ions. We discuss limitations of the computational experiment method and compare simulation results with data from Lovozero and Tuloma observatories.
The paper reports the results of simulation of cosmic ray proton transport through Earth’s atmosphere. The main objective of this work is to obtain characteristics of secondary particle fluxes at ...different altitudes and to convert them to equivalent dose values. The technique for the conversion is based on numerical simulation of interaction between the particles and an anthropomorphic phantom. The paper examines two cases, using a model source of primary proton spectra as input parameters, which correspond to both purely galactic cosmic rays and solar cosmic rays. The computational results are tabulated for the altitude range from 0 km to 11 km above sea level; the upper range value corresponds to the flight altitude of civilian airliners. These results are shown to agree well with the results obtained by other research teams.
A comparative analysis is performed of data on variations in the electromagnetic component over a solar cycle (SC) to study increases in gamma radiation in different phases of an SC. Variations in ...the intensity of cosmic rays are detected in Apatity by different detectors for all main components of secondary cosmic rays: nucleonic, electron–muonic, and electromagnetic (gamma radiation).
The article considers the production kinetics of vibrationally excited NO(X
2
Π,
> 0) molecules at heights of Earth’s middle atmosphere during the precipitation of high-energy protons. The intensity ...profiles of the luminescence of the infrared bands of nitric oxide at 5.3 and 2.7 μm were calculated for precipitation of high-energy protons into Earth’s atmosphere during the events GLE65, GLE67, GLE69, and GLE70 of the 23rd solar cycle. Calculations have shown that the highest integral luminescence intensity values of the 5.3 and 2.7 μm bands were obtained for GLE69: 5.7 and 0.18 kR (kilorayleighs), respectively. Comparison of the calculation results for the 5.3 µm band during the GLE69 event with experimental data obtained from the TIMED spacecraft on January 20, 2005, showed that the calculation results were overestimated by a factor of 2.
GLE73 Event (October 28, 2021) in Solar Cosmic Rays Balabin, Yu. V.; Gvozdevsky, B. B.; Germanenko, A. V. ...
Bulletin of the Russian Academy of Sciences. Physics,
12/2022, Letnik:
86, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Results are presented from analyzing the GLE73 event in terms of solar cosmic rays. The GLE73 event raised the count by 2–6% at polar stations of the World Neutron Monitor Network. A direct solution ...to the inverse problem is found, along with and the energy spectra of solar cosmic rays at the boundary of the magnetosphere are obtained and the pitch angle distribution of the flux.
We report the measurement results of differential spectra of electromagnetic radiation in the range 0.1–4 MeV, which occurs in the atmosphere as a component of secondary cosmic rays. Spectral ...monitoring was performed using a spectrometer based on the Nai (TL) crystal in 2022–2023. The main purpose of the measurements was to determine spectral characteristics of the electromagnetic radiation during increase events, when the electromagnetic radiation flux from the atmosphere rises by tens of percent with respect to the background level. From a thorough analysis of the spectra of many dozens of events, we have drawn a conclusion that although the lines of natural radionuclides are present on the spectra and contribute their share, their total contribution to the increase events is ~0.1 of the total energy supplied during an increase. We unambiguously conclude that the effect of increasing electromagnetic radiation during precipitation is not due to the presence of radionuclides in precipitation.
Descriptions and technical characteristics are given for compact Geiger counters designed to verify calculations of cosmic ray transport through the Earth’s atmosphere . Results are presented in the ...form of a comparison of the altitude profiles of count rates of charged particles, obtained via modeling and field experiments.
A portable complex for detecting secondary cosmic ray is developed and built for monitoring cosmic rays during expeditions and in remote locations and lighthouses. The complex contains detectors of ...neutrons, charged particles, and gamma fluxes. It is tested during expeditions in the Barents and Greenland seas.
