On the characteristics of solar activity and galactic cosmic ray intensity at the solar cycle maximum and inflection points

The correlation between the characteristics (sunspot area and galactic cosmic ray intensity) at inflection points and at the solar cycle maximum is discussed. Probable characteristics in the forthcoming maximum of cycle 24 are considered.     

Ultimate ground level enhancements of solar cosmic ray intensity

Possible values of ground level enhancements (GLEs) of the intensity of solar cosmic rays (SCRs) that can be recorded by neutron monitors (NMs) are estimated in two different ways for the ultimate spectra of solar protons. The first approach uses the statistical dependence between the maximum values of the integral proton flux >100 МeV and the GLE recorded by an NM. The second is to calculate the expected effect for the ultimate spectrum at a particular NM with known couple coefficients, atmospheric depth, and the threshold of the geomagnetic cutoff. Estimates using the first method vary from 9600 to 160000% for high-latitude NMs; estimates using the second method, from 1200 to 750000%. The obtained lower limits approximately correspond to GLE values observed earlier, and the upper limits are two orders of magnitude higher. Studies of the possible impact of solar proton events with spectra close to ultimate on the Earth’s atmosphere and biosphere should be continued.     

Galactic cosmic ray intensity in the inner and outer heliosphere in the epoch of the solar cycle 24 minimum

The behavior of the observed and expected Galactic cosmic ray (GRC) intensity both near the Earth and in the outer heliosphere is considered. The hypothesis is discussed of the strong dependence of the GCR intensity in the interaction region of the solar and interstellar winds on the heliospheric magnetic field polarity in the epoch of a solar activity minimum.     

On the formation of spot and magnetic cycles in the galactic cosmic ray intensity in the minima of solar activity

The problems of the determination and separation of variations in the galactic cosmic ray intensity, caused by the spot-forming activity and polarity of high-latitude solar magnetic fields, are discussed. Based on the solution of the boundary-value problem, some features in the intensity formation at solar cycle minima are formulated.     

Global and heliolatitude indices of solar activity and cosmic ray modulation

The time variation of the galactic cosmic rays (GCR) (1958–2006) is described using solar activity indices in the form Z^α, Z^α exp[?(φ/φ₀)^β], where Z and φ are one of the solar activity indices and the heliolatitude of sunspots; α, β, and φ₀ are the optimum parameters found by the least-squares method. The time variation of the GCR flux is satisfactorily described, the role of the active region heliolatitude in the index in relation to the cosmic ray modulation is revealed.     

Atmospheric effects in the intensity of cosmic ray muon bundles

We analyze experimental data on cosmic ray muon bundles collected with a DECOR coordinate detector. Substantial variations in the intensity of the events are observed during the experiment. These variations are found to be caused by changes in atmospheric conditions. This study is the first to obtain experimental estimates of the temperature and barometric coefficients for muon bundles. It is shown that the observed effect can be explained by changes in the side distribution function of EAS muons.     

Application of student’s criterion for detecting ground level enhancements of solar cosmic ray intensity

Student’s criterion is used to detect ground level enhancements of solar cosmic ray intensity at middle latitudes. Application of this test to the data recorded by Alma-Ata high-altitude neutron monitor made it possible to detect the arrival of solar-origin relativistic particles on November 6, 1997 and August 24, 1998.     

The 11-year cycle of solar activity and configurations of the planets

In this paper a parameter was used, viz., the average difference between the heliocentric longitudes (ADL) of the planets Venus, Earth, and Jupiter. For the minimum ADL (the planets are in conjunction), as well as at the minimum deviation of the planets from a line passing through them and the Sun at the location of the planets on opposite sides from the Sun, an index was composed that uniquely describes the 11-year cycle of solar activity.     

Induction mechanism of cosmic ray production and kinks in the cosmic ray spectrum

Two kinks are observed in the energy spectrum of galactic cosmic rays. It is shown that the entire spectrum can be described, to a good approximation, by a single formula obtained on the basis of the hypothesis that the particles are produced and accelerated in plasma pinches by an induction mechanism under the assumption that three hierarchical groups of currents are present—interstellar, galactic, and metagalactic. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 4, 225–230 (25 August 1996)     

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.     

Decay phase of energetic electrons and protons in solar cosmic ray events

The decay phase of solar energetic particle (proton and electron) events is considered. The propagation mechanisms for particles of different kind may differ in the same events, which should manifest itself in the pecularities of their decay phases. To compare the propagation parameters of protons and electrons, we used the data of simultaneous measurements of few-MeV proton and few-hundred-keV electron fluxes from IMP-8 CPME and SOHO COSTEP. Nearly half of clear-shaped simultaneously measured electron and proton decays have similar character (exponential or power-law), suggesting that at least in a part of events electrons can be subjected to the same propagation mechanisms as protons.     

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.     

Particle acceleration at astrophysical shocks: A theory of cosmic ray origin

The theory of first order Fermi acceleration at collisionless astrophysical shock fronts is reviewed. Observations suggest that shock waves in different astrophysical environments accelerate cosmic rays efficiently. In the first order process, high energy particles diffuse through Alfvén waves that scatter them and couple them to the background plasma. These particles gain energy, on the average, every time they cross the schock front and bounce off approaching scattering centers. Calculations demonstrate that the distribution function transmitted by a plane shock is roughly a power law in momentum with slope similar to that inferred in galactic cosmic ray sources. The generation of the scattering Alfvén waves by the streaming cosmic rays is described and it is argued that the wave amplitude is probably non-linear within sufficiently strong astrophysical shocks. Hydromagnetic scattering can operate on the thermal particles as well, possibly establishing the shock structure. This suggests a model of strong collisionless shocks in which high energy particles are inevitably produced very efficiently. Observable consequences of this model, together with its limitations and some alternatives, are described. Cosmic ray origin and astrophysical shocks can no longer be considered separately.     

Long-period variations in the characteristics of frontal zones in the north Atlantic and their relation to solar activity and cosmic ray variations

The oscillations of the temperature gradients with the periods of ～10 and ～22 years have been detected in the Arctic frontal zone near the Greenland coasts. It has been shown that geomagnetic activity and the rate of variations in the GCR flux in the 11-year solar cycle are the main factors affecting the temperature contrasts in the frontal zone. It has been noted that the detected variations in the frontal zone temperature characteristics are important for the formation of the solar activity effects on the intensity of extratropical cyclogenesis.     

Pulsations of the geomagnetic field associated with variations in cosmic ray intensity during thunderstorms

It was discovered that strong variations in the intensity of secondary cosmic rays observed during thunderstorms and earlier interpreted as a consequence of the cyclic generation of electrons and positrons in a strong electric field are accompanied in some cases by well-pronounced pulsations of the geomagnetic field. An experiment was performed with the CARPET array for studying extensive air showers of cosmic rays. This array, located in the Baksan Valley (North Caucasus), was used as a particle detector. Magnetic measurements were made using a high-precision magnetic variation station located deep underground in a tunnel of the Baksan Neutrino Observatory at a distance of about 4 km from the CARPET array.     

The search for ultrashort bursts of cosmic ray intensity on the Andyrchi air shower array

A new data acquisition system that makes it possible to measure the count rate of each detector of the Andyrchi air shower array every millisecond is described. This new detection system allows us to search for ultrashort bursts of cosmic ray intensity when operating the array in the single-component detection mode. The method of data acquisition and analysis is discussed.     

A study of daily variation in cosmic ray intensity during high/low amplitude days

A detailed study has been conducted on the long-term changes in the diurnal, semi-diurnal and tri-diurnal anisotropies of cosmic rays in terms of the high/low amplitude anisotropic wave train events (HAE/LAE) during the period 1981–94 using the neutron monitor data from Deep River Neutron Monitoring Station. In all, 38 HAE and 28 LAE cases have been studied. An inter-comparison of the first three harmonics during these events has been made so as to understand the basic reason for the occurrence of these types of events. It has been observed that the phase of diurnal anisotropy shifts towards earlier hours for HAEs and it shifts towards earlier hour as compared to 18-h direction for LAEs. For semi-diurnal anisotropy, phase remains statistically the same for both HAE and LAE. In the case of tri-diurnal anisotropy, phase is evenly distributed for both types of events. The interplanetary magnetic field (IMF) and solar wind plasma (SWP) parameters during these events are also investigated. It has also been observed that HAE/LAEs are weakly dependent on high-speed solar wind velocity. The two types of solar wind streams (corotating streams and flare-generated streams) produce significant deviations in cosmic ray intensity during HAE/LAE.      

Estimate of the cosmic ray background in an interferometric antenna for gravitational wave detection

The effect of the cosmic ray interaction in the masses of an interferometric antenna for gravitational wave (GW) detection is evaluated. In a 3 km antenna this background, mainly due to muons gives a limit, for 1 ms GW pulses, of h∼8.5×10^-23 with a frequency of 2×10^-1 events/year and 8.5×10^-26 with 4.1×10^-6 events/year. For GW having frequency>10 Hz the sensitivity limit is h∼1.7×10^-31. This background seems to allow unshielded operation of the interferometer test masses.     

The gravitational influence of Venus,the Earth,and Jupiter on the 11-year cycle of solar activity

This paper presents the calculations of the resulting tidal force of Jupiter, Venus, and Earth, that act on the Sun. Considering the tidal forces as the difference of gravitational forces that act on the extreme points of the Sun’s diameter and on the center of the Sun, it is shown that there are large variations in the resulting tidal force (RTF) at the moments of linear configurations of Venus, the Earth, and Jupiter, and that the maximum variations of the RTF are in a strong agreement with the minimum values of the JEV planetary index, as introduced by the author in previous works.