Ultrahigh-Energy Cosmic Rays: Results and Prospects

Observations of cosmic rays have been improved at all energies, both in terms of higher statistics and reduced systematics. As a result, the all-particle cosmic ray energy spectrum starts to exhibit more structures than could be seen previously. Most importantly, a second knee in the cosmic ray spectrum—dominated by heavy primaries—is reported just below 10¹⁷ eV. The light component, on the other hand, exhibits an ankle-like feature above 10¹⁷ eV and starts to dominate the flux at the ankle. The key question at the highest energies is about the origin of the flux suppression observed at energies above 5 · 10¹⁹ eV. Is this the long-awaited Greisen-Zatsepin-Kuzmin effect or the exhaustion of sources? The key to answering this question is again given by the still largely unknown mass composition at the highest energies. Data from different observatories do not quite agree, and common efforts have been started to settle that question. The high level of isotropy observed even at the highest energies starts to challenge a proton-dominated composition if extragalactic magnetic fields are on the order of a few nanogauss or more. We shall discuss the experimental and theoretical progress in the field and the prospects for the next decade.     

Quasiperiodic Variations of Solar Activity and Cosmic Rays

Quasiperiodic variations of various manifestations of solar activity, parameters of the interplanetary medium, and the flux of galactic cosmic rays (GCRs) are studied using the data of stratospheric sounding and measurements with neutron monitors. Groups of spectral components with periods of ~2, 1.3, and ~1 year are identified in the range of periods shorter than 5 years. Particular attention is paid to quasi-2-year GCR variations that are induced by similar variations of the mean magnetic field of the Sun and are integral to the processes of solar activity.     

宇宙线福布什下降期间羊八井云量的变化

进入地球大气中的宇宙线强度发生变化,可能导致气候,比如云量的变化. 利用羊八井中子监测器在2003—2004年观测到3次宇宙线福布什下降,在这期间同时记录了观测站点上空的云量变化. 通过对宇宙线福布什下降期间羊八井上空云量的统计分析发现,宇宙线福布什下降期间云量增加,即云量对宇宙线福布什下降表现出明显的负响应. 这表明,宇宙线福布什下降期间,低纬度薄云层地区云量增加,与其他观测结果相一致.     

Gamma Ray Astronomy and the Origin of Cosmic Rays

The classical production processes for high energy gamma radiation in the interstellar medium are discussed and confronted with recent satellite observations. It is shown that gamma ray data in their present form do not provide definite conclusions on the origin of cosmic rays. Some current ideas on the nature of gamma ray point sources are presented.     

Solid-state lasers for molecular spectroscopy of harmonic transitions developed at the IAO SB RAS

Physical principles are considered, top-priority results of investigations into lasers and harmonic molecular transitions are presented, and promising programs of investigations are outlined. Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 124–134, August, 1999.     

Letter: Ultra-High Energy Cosmic Rays and Symmetries of Spacetime

High energy cosmic rays allow probing phenomena that are inaccessible to accelerators. Observation of cosmic rays, presumably protons, with energies beyond 4 × 10¹⁹ eV, the so-called Greisen-Zatsepin-Kuzmin (GZK) cut-off, give origin to two puzzles: How do particles accelerate to such energies ? Are their sources within 50–100 Mpc from Earth, or Lorentz invariance is actually a broken symmetry ? We suggest an astrophysical test to verify the latter alternative and explore a possible connection with an alternative theory of gravity that exhibits preferred-frame effects.     

Supernova Remnants as Sources of Cosmic Rays and Nonthermal Emission

Physics of Atomic Nuclei - Cosmic ray acceleration by astrophysical shocks in supernova remnants is briefly reviewed. Results of numerical modeling taking into account magnetic field amplification...     

Modeling Source Spectra and Composition of Ultrahigh Energy Cosmic Rays

The inverse problem of cosmic ray transport of ultra-high energy cosmic rays is considered. The source spectrum and composition are derived based on the recent Auger data on energy spectrum, energy dependence of mean logarithm of atomic mass number and its variance. The dependence of results on the extrapolation of observable spectrum beyond energies 10²⁰ eV is investigated.

     

Method of Muonography and Prospects of Its Further Development

Physics of Atomic Nuclei - Muonography is an analog of other similar concepts such as X-ray radiography, electronography, neutronography, etc. based on the detection of penetrating radiation whose...     

Diurnal and Eleven- Year Variations of Neutron Component of Cosmic Rays

Cosmic ray ground observations are used together with the method of coupling coefficients to determine, by spectrographic method, the features of the variational primary energy spectrum of diurnal and eleven-year variations of neutron component of cosmic rays. It is found that the variational energy spectrum responsible for both types of variations can be best described by a constant spectrum up to an upper effective rigidity boundary. The upper cut-off effective rigidity boundary for the variational energy spectrum of diurnal variation was found to change from 105 GV at maximum solar activity to 15.85 GV at minimum solar activity. For Eleven-year variation, R_max was found to have a value of about 20 GV which changes slighly with solar activity due to the change of the coupling coefficients with solar activity.     

Conditions for Separation Rays by Their Arrival Time at Large Distances and Low Frequencies

Acoustical Physics - Abstract—The results of experimental studies on the propagation of low-frequency pulsed signals in deep- and shallow-water areas of the World Ocean are presented....     

Composition of Cosmic Rays with Energy More than 0.1 EeV by Long-Term Optical Observations of Cherenkov Emission at Yakutsk EAS Array

Physics of Atomic Nuclei - The paper presents results on longitudinal development of air showers with ultra-high energies and mass composition of cosmic rays 〈ln A〉. The data is...     

Causal Statistical Mechanics Calculation of Initial Cosmic Entropy and Quantum Gravity Prospects

We report on the consequences of applying thecausal laws to the statistical mechanical calculation ofthe initial cosmic entropy. It can be deduced that theentropy density tends to zero as one approaches the initial singularity. This result along withsome quantum gravity considerations lead us to theconclusion that the initial data of the physical fieldsare asymptotically homogeneous in that limit.     

宇宙线大气簇射μ子定点密度及原初能谱“膝”的研究

用梁王山宇宙线观测站的数据研究宇宙线大气簇射μ子定点密度谱,谱呈现明显的拐折.通过MonteCarlo模拟,得到拐点对应的能量约为1.7×10¹⁵eV,拐点前后原初能谱指数差约为0.43,证实了KASCADE实验μ子定点密度谱呈现拐折的首次观测结果,又一次推证了原初宇宙线能谱膝的存在.     

Analysis of Variations of the Muon and Hadron Components of Cosmic Rays at Different Phases of the Solar Activity During the 11-Year Solar Cycle

Physics of Atomic Nuclei - Variations of secondary cosmic rays on the Earth’s surface depend on the solar activity. To study these variations, neutron monitors and muon detectors are used....     

Optical Negasensors and Prospects of Their Applications

The basic types of optical negasensors - sensors based on the application of negative resistance, negative inductance andnegative capacitance, R, L, C-negatrons are presented. It is shown, that application of negative inductance andcapacitance is not connected with stability decreasing as at application of negative resistance and allows to risesensitivity of a optical sensor theoretically ad infinitum. The example design of multielement optical negasensor forairborne, underwater or biomedical imaging is given.