Vol 81, No 2 (2017)

Variations in the rigidity spectrum and anisotropy of cosmic rays during ground level enhancement (GLE) on January 6, 2014, is investigated using ground-based observations of cosmic rays (CRs) from the worldwide network of stations and spacecraft measurements obtained via a spectrographic global survey. The CR rigidity spectrum and relative variations in the intensity of CRs with rigidity of 4 GV are presented in the solar–ecliptic geocentric coordinate system in certain periods of the investigated event. It is shown that protons were accelerated during this GLE up to a particle rigidity of R ~ 2.4 GV. In the ~0.3 to ~2.4 GV range of rigidity, the CR differential rigidity spectra during the considered event were described by neither a power function nor an exponential function of particle rigidity. At the time of GLE, the Earth was in a loop-like IMF structure.

Large solar cosmic ray (SCR) events are registered by PLATAN equipment in September–October 1989 aboard the MIR orbital station and in October–November 2003 aboard the International Space Station (ISS). The energy spectra of Fe ions in the energy intervals of 5–200 MeV/nucleon (1989) and 25–90 MeV/nucleon (2003) are measured. Spectra for SCR events of 1989 and 2003 are approximated with high accuracy by the power law function of energy. The SCR events of 1989 greatly exceed those of 2003 in the fluence of Fe particles. High enrichment of the elemental composition of the SCR events 2003 with Fe ions is observed.

The results from observing Jovian electrons in the vicinity of the Earth are discussed. Variations in Jovian electron flows are observed during 14 rotations of the Sun in 2007–2008. The results are analyzed by assuming the existence of magnetic traps in the space between the Sun and Jupiter that are filled with electrons near Jupiter, and are then registered when the traps pass by the Earth. The average period of variation in the Jovian electron flow during the 14 solar rotations is 26.2 days instead of the expected synodic period of the Sun–Earth system equal to 27.3 days. An explanation for this phenomenon is proposed.

Possible mechanisms responsible for changes in the solar wind’s isotope component caused by interaction between solar flare protons and helium isotopes with photospheric nuclei are considered. Depth profiles of the rates of ⁶Li, ⁷Li, ⁷Be, ¹⁴C production in the solar atmosphere are simulated using the GEANT4 software package. It is concluded that anomalous isotopic compositions of the solar wind relative to the average values can form during the coronal mass ejections.

The preliminary results from measurements of deuteron fluxes in galactic cosmic rays (GCR) in the vicinity of the Earth in 2006–2009 are presented. The results are obtained by analyzing data from the PAMELA experiment aboard the Resurs DK-1 satellite. High-precision detection instruments provided an opportunity to identify GCR deuterons and measure their spectrum in the energy interval of 90–650MeV/nucleon. Spectra averaged over six-month intervals from the summer of 2006 to the summer of 2009 (the solar activity minimum) are presented. The influence of solar modulation on the observed spectrum is clearly seen in the results.

Simulations of how secondary components of cosmic rays are generated and pass through the atmosphere are performed using the CORSIKA software package. The relationship between the vertical projection of the local anisotropy vector A_Z and the index of primary particle spectrum γ is calculated. The time series of A_Z for 2007–2015 are obtained using data from the URAGAN muon hodoscope. Matrix data corrected for barometric and temperature effects are used to estimate A_Z. Using the A_Z time series, the average annual daily variations Δγ are estimated. Annual and daily variations in the slope of the energy spectrum of primary protons are observed.

Calculations of the spectra of galactic cosmic rays (GCR) reveal crossovers of them in successive solar activity minima. The minima of consecutive 11-year cycles differ in the direction of the heliospheric magnetic field, and thus in the direction and magnitude of drift GCR fluxes. The crossover of spectra at relatively low proton energies (Е ~ 1.3 GeV) could explain the difference between the integral (in terms of energy) GCR intensities in consecutive 11-year cycles, noted in observations performed aboard spacecraft, in the stratosphere, and with neutron monitors.

The high-altitude track of the rates of production of cosmogenic isotopes ¹⁴С, ¹⁰Be and ³⁶Cl in the Earth’s atmosphere under the action of galactic cosmic rays is calculated using different intranuclear cascade models in the GEANT4 environment. Inferences based on these models are discussed in comparison to the available experimental data on these isotopes.

The June 2015 Forbush effect is studied using ground-based measurement data on cosmic rays (CRs), obtained from the worldwide network of stations by the spectrographic global survey. When approximating the variation spectra via the exponential function of particle rigidity in the 10–50 GV range, the spectrum index is higher at the phase of maximum modulation than at those of the drop in CR intensity and its recovery.

Coronal mass ejections are the brightest manifestations of solar activity. Dozens of coronal mass ejections are observed daily during periods of higher solar activity. They directly affect cosmic ray fluxes that carry information on plasma clouds, including clouds moving toward the Earth. Several aspects of geoeffective and non-geoeffective coronal mass ejections, observed with the ground-based URAGAN muon hodoscope operated as part of the NEVOD experimental complex at MEPhI, are discussed. The anisotropy of cosmic ray muon fluxes recorded during coronal mass ejections in 2014 and 2015 is investigated.

In passing through the heliosphere, the cosmic ray flux changes its properties (energy and angular distribution) due to the influence of interplanetary medium. As a consequence, the muon flux generated by primary cosmic rays in the Earth’s atmosphere changes its properties as well. Muons detected on the Earth’s surface are mostly generated by primary protons and helium nuclei with energies of 10 GeV to TeV. The interplanetary magnetic field has a great impact on the trajectories of these particles in the heliosphere. Constructing the back trajectories of the particles from the detector on the Earth’s surface to the region of the heliosphere allows us to evaluate the relationship between trajectories of muons and primary particles. This work presents calculated trajectories of muons, parental protons, and helium nuclei with different energies for positive and negative Sun polarity. It is shown that changing the Sun’s polarity leads to qualitative changes in the regions of the heliosphere through which primary particles pass.

Results from investigating the behavior of zonal components of the first two angular moments of the distribution of cosmic rays observed in 2015 are presented. The global survey approach developed at the Institute of Cosmophysical Research and Aeronomy, Siberian Branch, Russian Academy of Sciences, is used to determine the zonal harmonics. In this technique, the worldwide network of neutron monitors acts as a single multidirectional detector of cosmic rays. It is shown that sharp increases in the positive amplitudes of zonal harmonics, considered to be predictors of geomagnetic field disturbances with a probability of ~0.75, precede geomagnetic storms with Dst < −50 nT. A geomagnetic storm predictor becomes apparent in periods of time from several hours to 1.5 days. Geomagnetic disturbances are currently monitored in real time using the global survey approach based on data from the worldwide neutron monitor database (http://www.nmdb.eu). The initial results from forecasting can be found on the Internet (http://www.ysn.ru/~starodub/SpaceWeather/global_survey_real_time.html).

Measurements of high-energy proton fluxes (30–100 MeV) by the low-orbit satellite experiments ARINA (Resurs-DK1 satellite; inclination, ~70°; altitude, ~600 km; 2006–2016) and VSPLESK (International Space Station (ISS); inclination, ~52°; altitude, ~400 km; 2008–2013) are considered. The spectrometers have the same physical layouts, 10% energy resolution, and 7° angular resolution. Proton fluxes of different energies in the inner radiation belt (L < 2.0) are analyzed. The period of observation covers the declining phase of the 23rd solar cycle and the main part of the 24th cycle. The distribution of fluxes is analyzed for different proton energies, L-shells, and geomagnetic field inductions. It is shown that depending on the L-shell, proton fluxes can grow by up to 7 times (L = 1.16) during the Solar minimum, compared to the Solar maximum.

The daily fluence is selected as the main characteristic of the behavior of electrons with E > 2 MeV measured by GOES satellites in geostationary orbits, since this characteristic is closely associated with malfunctions of satellite electronic equipment. It is shown that increases in the flux of high-energy magnetospheric electrons are associated with considerable interplanetary and magnetospheric perturbations, but lag behind them by 1–3 days. A greatly increased solar wind speed is observed as early as 3 days before the electron flux starts to grow, with a maximum being reached by the onset of growth. It is shown that the electron fluence is weakly associated with the level of geomagnetic activity on the same day but correlates to the А_р index of geomagnetic activity observed 2–3 days earlier. The fluence of high-energy magnetospheric electrons is closely associated with the solar wind’s speed, especially with its value measured 2 days earlier.

The interrelation between gamma-ray bursts of lightning origin and high-energy electron bursts registered in near-Earth space below the radiation belt is sought and investigated. Data from the ARINA and VSPLESK satellite experiments, developed to register high-energy electron bursts with energies in the range of 3–30 MeV, and the databases of the RHESSI space observatory, which contain data on gamma flashes of geophysical origin with energies of up to 17 MeV, are used. The results from analyzing electron bursts and gamma flashes that coincide up to ten minutes in time and are located on the same L-shell are presented.

An array of scintillators tightly packed in the horizontal plane and designed for recording secondary particles produced by cosmic rays is capable of probing the angular dependence of intensity disturbances caused by electric fields of a thunderstorm atmosphere. The basic parameters of thunderstorm activity are estimated using a specific example of variation in intensity in different ranges of energy release in the detectors. These parameters include the characteristic radius of the active region (5 km), its total charge (30 C), the accumulated electric field energy (6 GJ), and the potential difference in the stratosphere above the active thunderstorm region (375 MV).

We analyze models based on the concept of “runaway” electrons used for explaining terrestrial gamma flashes (TGFs), observed by orbiting gamma ray observatories and thunderstorm ground enhancements (TGEs), particle fluxes from the thunderclouds, significantly enhancing the intensity of cosmic rays detected on the earth’s surface. We show that for explaining the TGE it is not necessary to invoke the relativistic feedback discharge model (RFDM) used for the explaining of the TGF initiation.

Three units of neutron detectors and four blocks of gamma-ray spectrometers have been installed and started operation at Complejo Astronomico El Leoncito, CASLEO (San Juan, Argentina; coordinates 31 S, 69 W; height of 2550 m; the rigidity of geomagnetic cutoff of R_c = 9.7 GV) in May 2015 as part of the scientific cooperation between the Lebedev Physical Institute, Russian Academy of Sciences (Moscow, Russia), Universidade Presbiteriana Mackenzie (San Paulo, Brazil) and Complejo Astronomico El Leoncito, CASLEO (San Juan, Argentina). Measurements with the new detectors greatly supplement the experimental data on variations in the charged component of cosmic rays obtained by the CARPET ground-based cosmic ray detector in 2006. The first results from a joint analysis of new experimental data are presented. Particular attention is given to growing cosmic ray fluxes associated with changes in the surface electric field. The main characteristics of the events recorded in January 2016 are presented.

The Earth’s global temperature is treated as indicator of climate changes. Relatively reliable assessments of temperature variations are obtained on the basis of results from instrumental observations performed only since the middle of the 19th century. It is significant that the temperature series are nonstationary, a consequence of global climate changes. Empirical mode decomposition (EMD) is used for temperature series pretreatment, allowing us to eliminate a long-term component and a linear trend. Along with expansion in the EMD series, analysis of the amplitudes of significance is used to eliminate noise. The resulting refined quasistationary series of data on the Earth’s surface temperature is studied via spectral analysis to identify the cyclic component.

The effect powerful solar proton events have on changes in temperature in layers of the Earth’s atmosphere up to 41 km above the surface at the decrease stage of 23rd cycle of solar activity is investigated. It is found that during proton events, the temperature of the bottom layers of the Earth’s atmosphere (at altitudes up to 11 km) rises on average by 0.08 K, and for the upper layers (from 17 to 41 km) it falls on average by 0.18 K. For 3–8 days after the event, the observed effect is reversed. The changes in temperature at sea level and in the atmospheric layer at 14 km (the most likely position of the tropopause) do not display such a tendency.