Cosmic rays in the Earth’s atmosphere

This paper presents a brief historical overview of studies of cosmic rays in the Earth’s atmosphere, which were initiated and led by S.N. Vernov for over 50 years. The main results of these studies that were obtained in recent decades are given. They include the study of the processes of generation and propagation of solar cosmic rays, the modulation of galactic cosmic rays in the heliomagnetosphere, and the role of cosmic rays in atmospheric processes.     

Paleoastrophysics: Progress and prospects

Results of highly accurate measurements of the radiocarbon concentration in the annual growth rings of trees over the last 400 years are presented. The temporal behavior of the intensity of galactic cosmic rays is reconstructed for the first time for the periods before, during, and after a deep and extended solar activity minimum — the Maunder minimum (1645–1715). It was established that even during the epoch of a deep solar minimum, the intensity of the galactic cosmic rays experienced solar modulation. The time profile of the generation of high-energy gamma radiation from the supernova explosion of 1006 is established. It is shown that processes of particle acceleration and generation of high-energy gamma rays take place with a three-year delay relative to the onset of the optical flare. The time profile of the generation of solar cosmic rays was obtained for the first time over the last thirty cycles of solar activity by precision measurements of the nitrate content in the polar ice cap. It is shown that solar flares accompanied by the generation of cosmic rays occur during the growth and decay phase of solar activity (measured by the Wolf numbers). Research prospects in the field of experimental paleoastrophysics are discussed. Zh. Tekh. Fiz. 69, 90–93 (September 1999)     

Predicting dangerous radiation fluxes of solar cosmic rays on the basis of data from neutron monitors

We discuss the possibility of predicting dangerous radiation fluxes of solar cosmic rays (SCRs) with energies of tens to hundreds of MeV on the basis of data from neutron monitors located on the Earth’s surface. Neutron monitors record relativistic cosmic rays (energies of 0.5 to several GeV) with minimal delay, but the intensity of cosmic rays is low in the high-energy region and does not pose a serious radiation hazard. By determining the spectrum of cosmic rays at high energies, however, it is possible to forecast radiation dangerous particle fluxes of moderate energies with a lead time of several hours. Such forecasts are, however, possible only with data on the so-called delay component of relativistic cosmic rays.     

Low cloud properties influenced by cosmic rays

The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (相似文献   

Energy spectrum and flows of solar cosmic rays during periods of their ground level enhancement

Events of the ground level enhancement of relativistic solar cosmic rays are studied using data from the world network of neutron monitor stations. The energy spectrum index and the absolute flow of solar cosmic rays for 15 GLE events observed between 1977 and 2012 are estimated from their effective energies [1]. The dynamics of changes in the index of the power energy spectrum γ in the range from 3 to 7 is observed.     

Connections between neutron monitor count rate and solar modulation strength

We suggest a new approach to the normalisation of neutron monitor response to galactic cosmic rays. The reference normalisation count rate is the neutron monitor response to the model unmodulated flux of galactic cosmic rays. A comparison of the actually recorded neutron monitor count rate with the calculated normalisation count rate can provide one with an observationally obtained true-of-date integral measure of the current level of solar modulation of galactic cosmic rays. The Slovak VEGA grant agency is acknowledged for the grant 2-5137.     

Cosmic ray-aerosol-cloud interactions in the atmospheric environment: Theoretical aspects

The microphysical and radiative processes involved in the interaction of cosmic radiation with the aerosol particulates in the atmosphere aggravate the ion-induced formation of aerosol particles that can act as cloud condensation nuclei (CCN). This may in turn affect the cloud droplet distribution and optical properties of clouds and enhance the process of rising global temperature depending upon the microphysical mechanism. Major observational information about the abundance of aerosols in the tropical atmosphere are obtained from the Indian Ocean experiment (INDOEX) field experiments and about the solar activity and solar cycle from the satellite observations. It has been noticed that when solar activity is less, more cosmic rays pass through the atmosphere, which activate the aerosols already present in the tropical atmosphere. The fluctuations in the cosmic rays due to variations in the solar activity can produce significant changes in the atmospheric environment.     

Behavior of the intensity of galactic and anomalous cosmic rays in the outer heliosphere and large-scale electric fields

The behavior of the intensity of anomalous and galactic cosmic rays in the outer heliosphere is compared. The previous hypothesis, according to which the lowest energy galactic cosmic rays affected by large-scale electric fields far beyond the termination shock wave of the solar wind may contribute to the behavior of the anomalous component intensity, is analyzed.     

Solar Flare Activity from 2006 to 2016 according to Data from the PAMELA and ARINA Spectrometers

In the period from 2006 to 2016, experiments based on the use of the PAMELA and ARINA spectrometers and aimed at detecting cosmic rays were performed on board the RESURS-DK1 satellite. Although the main goal of these experiments was to study the galactic component of cosmic rays, the instruments in question also detected, over a broad energy range, solar particles accelerated in powerful explosive processes on the Sun (solar flares). A list of solar events in which the PAMELA and ARINA spectrometers detected, in various years of their operation, an increase in the intensities of fluxes of solar protons whose energies were above 45 MeV is presented among other things.     

Strong signature of the active Sun in 100 years of terrestrial insolation data

Terrestrial solar irradiance data of the Smithsonian Astrophysical Observatory from 1905 to 1954 and of Mauna Loa Observatory from 1958 to 2008 are analyzed. The analysis shows that, with changing solar activity, the atmosphere modifies the solar irradiance on the percentage level, in all likelihood via cosmic ray intensity variations produced by the active sun. The analysis strongly suggests that cosmic rays cause a large part of the atmospheric aerosols. These aerosols show specific absorption and scattering properties due to an inner structure of hydrated ionic centers, most probably of O₂^‐ and O₂⁺ produced by the cosmic rays.     

On the structure of galactic cosmic ray intensity during its long-term variations

The structure of GCR intensity and its changes during the solar magnetic cycle are analyzed by numerically solving its transport equation. We propose a research method that allows us to use the intermediate results from numerical calculations, to resolve the intensity of galactic cosmic rays into components caused by sunspot and magnetic solar cycles, and to monitor the changes in energy in different parts of the heliosphere and different phases of the cycle. A method for dividing intensity into its components associated with the main physical processes determining the modulation of galactic cosmic rays is also proposed.     

Forbush decreases in the 19th solar cycle

The 19th solar cycle was characterized by abnormally high solar activity; unfortunately, the possibilities of observing it were limited. Ground-based observations of cosmic rays and geomagnetic activity are among the few types of continuous measurements that allow statements about the events of 19th cycle and their comparison with events of other cycles. Comparison of the events in cosmic rays with solar and geomagnetic activities shows that the number and strength of magnetic storms in the 19th cycle correspond to an abnormally high number of sunspots. However, large Forbush decreases were lacking in this cycle. The most powerful ICMEs of the 19th cycle were generally weaker than the greatest ones in later periods.     

利用羊八井中子监测器研究宇宙线的太阳日周期变化

通过对宇宙线周期变化研究可以得到宇宙线产生和传播区域的重要信息,是宇宙线长期研究的重要热点问题。利用位于西藏羊八井(地磁截止刚度:14.1 GeV) 的中子监测器2006 至2011年的观测数据,研究宇宙线的太阳日周期变化。在对中子监测器观测数据进行气压修正后,通过Lomb-Scargle 傅立叶变换法对修正后的数据进行周期分析,发现宇宙线计数率存在超过地球公转运动Compton-Getting 效应的太阳日周期变化,该周期变化可能是地球公转效应和宇宙线传播物理过程调制效应以及剩余气象效应的叠加。计算分析了1 日周期信号的振幅和初相位随时间的变化,发现1 日周期变化的初相位存在较为明显的年周期变化规律,这可能是地球公转和自转合成运动的结果;1 日周期变化幅度在2010 年后出现增大趋势。这些结果对宇宙线周期变化和各向异性的研究具有重要参考意义。With the study of the cosmic rays' solar diurnal variation we can get the important information about Cosmic Ray's production and propagation. It's important issues of cosmic rays' studies. We analyze the temporal variation of cosmic rays rate observed with the Yangbajing neutron monitor during 2006 to 2011, and nd semidiurnal and diurnal period signals included in the rates of cosmic rays with vertical rigidity equal to 14.1 GV. We have checked the time dependence of the phase and the amplitude of semidiurnal and diurnal anisotropy, and nd that the phase of diurnal signal varies yearly, it could be a synthetic movement of the earth's rotation and revolution. The amplitude before 2010 is obvious smaller than that after 2010. These results are of great reference value for studying the anisotropy and time variation of cosmic rays.     

Features of cosmic ray variation at the phase of the minimum between the 23rd and 24th solar cycles

The minimum between the 23rd and 24th cycles of solar activity was unusually deep and extended. The modulation of cosmic rays was minimal for the more than 70-year-long period of direct measurements. The data from stratospheric measurements by the Lebedev Physical Institute suggest that the flux of cosmic rays with more than 100 MeV/nucleon of energy exceeded the highest ever observed level (May 1965) by almost 12%. However, the ground-based neutron monitors sensitive to relatively high energies indicated that the flux of cosmic rays increased by less than 3%. This work compares the variations in the cosmic rays over periods of five minima of solar activity (the 20th to the 24th cycle). It is shown that in late 2008, an extra flux of particles with energies less than several GeV/nucleon was detected in the Earth’s orbit. A similar (though far smaller in scale) phenomenon was also observed in 1987 at the same orientation of the Sun’s magnetic field A < 0, but was not observed in epochs where A > 0.     

On the intensity of galactic cosmic rays in the inner heliosphere during epochs of minimum solar activity

The behavior of the intensity of cosmic rays of galactic origin in the inner heliosphere (r ?? 10 a. u.) during the minima of solar cycles 20?C24 is considered. The features of cosmic ray characteristics in the last anomalously long and deep minimum of solar cycle 24 (2007?C2010) are discussed.     

The influence of solar flares on the near-Earth space radiation environment in March and April 2013: Possibilities of operational monitoring

This paper deals with the operational analysis of the influence of solar flares, which produced solar cosmic rays, on the near-Earth radiation environment in space during the period from March 1 to April 18, 2013.     

Temporal changes in the energy spectrum of Forbush decreases in 20–23 solar activity cycles

Variations in the energy spectrum of galactic cosmic rays during Forbush decreases registered in the 20–23 solar activity cycles are studied, using the data from neutron monitors and the Yakutsk cosmic ray spectrograph. It is shown that the Forbush decreases in the 23rd cycle of solar activity had a harder energy spectrum than in the three previous cycles, due to the relatively low level of turbulence of the interplanetary magnetic field during the 23rd solar activity cycle.     

Studying semidiurnal variations in galactic cosmic rays

Seasonal changes in the semidiurnal variation of cosmic rays and their changes with the level of solar activity are discovered as a result of the long-term recording of cosmic rays by the spectrograph in Yakutsk (62°01′ N, 129°43′ E) and multidirectional muon telescope at Nagoya (35°10′ N, 136°58′ E). Seasonal changes are simulated using mechanisms proposed earlier by the authors.     

New method for estimating the absolute flux and energy spectrum of solar cosmic rays based on neutron-monitor data

A new method is described for estimating the absolute flux of solar cosmic rays based on the data from a single neutron monitor. The method is capable of yielding the energy spectrum at the isotropic phase of a solar flare using the available data from the currently operable worldwide network of cosmic-ray stations. The method is based on the determination of the effective momentum or energy for which the particle flux derived from the neutron-monitor count rate is weakly sensitive to small variations in the exponent of the power-law spectrum. A comparison of the calculations with direct space-borne measurements and calculations by other authors based on the data from the neutron-monitor network shows their satisfactory agreement for the last ground-level enhancement of solar cosmic rays observed on December 13, 2006.     

VH-nuclei cosmic ray tracks in silicate minerals of howardites: A regolith stage of parent body formation

Natural tracks in pyroxene and plagioclase crystals from Erevan and Kapoeta howardites are due to irradiation by both galactic and solar cosmic rays.