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Vol 61, No 1 (2023)
Articles
Energy Spectra of 3He, 4He, C, O, and Fe Suprathermal Ions per 1 AU in Particle Flows from Coronal Holes in the 23rd and 24th Solar Cycles
Abstract
The energy spectra of ions 3He, 4He, C, O and Fe with energies of 0.04–2 MeV/nucleon were studied at 1 AU in solar-wind streams from near-equatorial coronal holes during the decline of solar activity in cycle 23 according to the information of the ULEIS, SWICS, and SWEPAM instruments installed onboard the ACE spacecraft. The results of this work show that suprathermal ions from coronal holes are Maxwellian solar-wind ions accelerated on the Sun and/or in interplanetary space and form a high-energy contribution to solar-wind ions (a suprathermal “tail” in the energy distribution of solar-wind ions). The energy spectra of accelerated “tail” ions have different dependences on energy, which indicates different mechanisms of their acceleration. The relationship between the intensity of suprathermal ions and the speed of the solar wind indicates the effectiveness of the acceleration of Maxwellian solar-wind ions.
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Fe Ion Composition in Solar-Wind Streams in the Solar Corona and Heliosphere
Abstract
Analysis of the distributions of Fe ions over the stages of ionization in solar-wind (SW) plasma provides valuable information on the formation of SW streams and plasma heating processes, as well as for identifying SW sources on the Sun. When passing SW plasma through the corona, its ion composition evolves and finally “freezes” at distances of the order of several solar radii from the solar surface, remaining further practically unchanged in the heliosphere. This makes it possible to obtain information about the physical conditions in its source and the solar corona from the SW charge state. Average charge QFe, which is usually used to characterize the distributions of Fe ions, does not take into account all the features of the evolution of the ion composition, which does not allow one to extract more detailed information about the state of SW plasma. In this study, to describe the charge state of Fe ions, three parameters q4, q8, and q12 are introduced, which characterize the relative fractions of ions with charges Z = 0–7, 8–11, and 12–20, respectively, and conditionally correspond to “cold,” “medium,” and “hot” SW plasma components. According to the measurements of the Fe ion composition in 2010 on the STEREO-A spacecraft, the characteristic values of these parameters for different types of SW streams are given. The problem of modeling ion distributions in SW plasma based on diagnostic data on the parameters of coronal sources is considered. Using the example of the event associated with coronal-mass ejection on August 18, 2010, it is shown that the parameters of the charge state of Fe ions calculated from the model distributions are in good agreement within errors with the measurement data.
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The Relationship of Magnetospheric Parameters with Cosmic-Ray Cutoff Rigidities Depending on Latitude
Abstract
We have studied the features of the latitudinal behavior of geomagnetic thresholds of cosmic rays R, as well as their sensitivity to the interplanetary medium and magnetospheric parameters during three phases of the magnetic storm on September 7–8, 2017, in the initial, main, and recovery phases. For this purpose, values of R were calculated in two different ways—by the method of spectrographic global survey (Rsgs) and by the method of tracing the trajectories of cosmic-ray (CR) particles in the model magnetic field (Ref). The maximum lowering of thresholds is observed at the storm maximum (Dst = –142 nT), reaching the values of ΔRsgs = –0.52 GV and ΔRef = –0.66 GV. The curve of ΔRsgs variations, depending on the observation station (latitude) cutoff rigidity, assumes a classical form with a maximum dropping the thresholds at midlatitudinal stations. ΔR correlates most strongly with the Dst index, which indicates that the ring current plays a main part in the dependence of variations of CR cutoff rigidities. The significant influence of solar-wind velocity V and interplanetary magnetic field (IMF) parameters on ΔRsgs and ΔRef is also seen. In the main phase, ΔRef depends on B and Bz of the IMF, and ΔRsgs depends on B and By. For ΔRsgs, the correlation with electromagnetic parameters varies, depending on the observation station, in a regular manner. There is no such tendency for ΔRef.
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Spectroradiometry of the Solar Corona on the RATAN-600
Abstract
Modern studies of solar radio emission are complicated by continuous power amplification and multifrequency external interference, which often completely overlap important frequency ranges. Many topical problems in solar radio astronomy require large effective areas of radio telescopes, high frequency and time resolutions, accurate spatial measurements, and a large dynamic range. It becomes relevant to change the concept of receiving recording equipment. This paper deals with topical problems of the physics of the solar corona in combination with optimal methods of observation with large instruments. The features and difficulties of combining high parameters—dynamic, spatial, temporal, and frequency resolutions—are considered. The proposed solutions of the new-generation observation complex implement the possibilities of intelligent selection of registration conditions in a multioctave mode with multichannel over 8000 channels/GHz with temporary permission up to 8 ms/spectrum. A multiobject observation mode becomes available from powerful flaring objects to faint structures of various nature. High-speed data processing makes it possible to implement an online mode of interference elimination, which is based on a fast statistical analysis of the spectrum with the selection of non-Gaussian (interference) structures. Methods for high-speed analysis of large-volume data (the principal component analysis method) and their presentation to the user are proposed. Examples of the operation of the complex in the range of 1–3 GHz are given. The prospects of a new approach for multiobject radio astronomy observations in the implementation of the RATAN-600 tracking mode are considered: from recombination lines to wide-range spectra, from low-contrast fluctuations to fast changes in flares, etc.
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Characteristics of Solar Wind and Geomagnetic Conditions of Extreme Geomagnetically Induced Currents at the Vykhodnoy Station (2012–2018)
Abstract
We investigated 140 events with the largest geomagnetically induced currents (GIC) recorded at the Vykhodnoy station (65 MLat) in 2012–2018. The significant differences between the parameters of the solar wind and geomagnetic indices from typical values are shown. Distinctive increases in solar wind velocity and dynamic pressure, decreases of IMF Bz are found. The Kp, AE, AL, Dst indices, as well as the Dst rate of growth Dst/dt are significantly shifted from the usual values. The relationship with interplanetary shocks in the solar wind is also analyzed.
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On Residual Modulation of Galactic Cosmic Rays in the Heliosphere
Abstract
The residual modulation of galactic cosmic rays and its energy dependence have been investigated using data from three types of ground-based detectors and from PAMELA, AMS-02, Voyager 1, and Voyager 2 data. Quantitative estimates of the residual modulation in the range of rigidities of 4–41 GV were obtained. It was shown that the residual modulation is approximately the same in magnitude as the modulation due to the solar activity cycle that allows us to draw some conclusions about the modulation processes in the heliosphere. The energy spectrum of the residual modulation was obtained. A comparison was made with the results of other authors up to the Maunder epoch.
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Exploration of the Moon by Automatic Spacecraft
Abstract
Problems of the study and exploration of the Moon, which is of paramount interest for cosmogony, planetology, and Earth sciences in the context of a comprehensive study of the Solar System, are discussed. A historical review of lunar exploration is given, a fundamental contribution to which was made by the Soviet lunar program, carried out with the help of automatic spacecraft in the first decades of the space age. The review is timed to coincide with the revival of lunar exploration within the framework of the Russian national space program. The current state of knowledge about the Moon is considered—first of all, key questions about its origin and early evolution. This is of paramount importance for the reconstruction of the main processes of formation of the entire family of bodies in the Solar System, including the early history of the Earth, as well as the reasons for the various evolutionary paths of the Earth and the terrestrial planets. At the present stage, exploration of the Moon as a strategic foothold on the path of human space exploration and the creation of elements of the future lunar infrastructure using local natural resources in the potentially most demanded polar regions are urgent. The South Pole is the target of the Russian Luna-25 and Luna-27 missions, with an extensive science program that aims to start a multipurpose program with the efficient use of new-generation robotics. This program predates Russian plans for manned flights to the Moon.
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Preliminary Results of Data Processing of the TRITEL Dosimeter as Part of the Matryoshka-R Space Experiment onboard the Russian Segment of the International Space Station
Abstract
Preliminary results of processing data from the TRITEL dosimetric equipment, which consists of one interface unit and three units of mutually orthogonal telescopes of silicon detectors operating in the coincidence mode (with the possibility of obtaining data also from a single mode of operation), are presented. The TRITEL dosimeter was designed to study the temporal dynamics of dose loads and the anisotropy of charged particle fluxes at various points of the Service Module (SM) of the Russian segment of the International Space Station (RS ISS) with the additional possibility of measurements in other modules of the RS ISS. As part of the Matryoshka-R space experiment (SE) on the RS ISS the TRITEL dosimeter was in operation from mid-October 2017 to mid-October 2020. The article presents a description of the methodology for processing dosimetric data of the TRITEL equipment and preliminary results of processing data obtained in the period from June to October 2020.
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