Component Of Cosmic Rays Research Articles

Cardiovascular effects of space radiation: implications for future human deep space exploration.

A manned mission to Mars has been contemplated by the world's largest space agencies for a number of years. The duration of the trip would necessitate a much longer exposure to deep space radiation than any human has ever been exposed to in the past. Concern regarding cancer risk has thus far stalled the progress of deep space exploration; however, the effect of space radiation on the cardiovascular system is significantly less well understood. Damage by radiation in space is mediated by a number of sources, including X-rays, protons and heavier charged atomic nuclei (HZE ions, the high-energy component of galactic cosmic rays). Previously, only lunar mission astronauts have been exposed to significant deep space radiation, with all other missions being low earth orbits only. The effect of this radiation on the human body has been inconclusively studied, and the long-term damage caused to the vascular endothelium by this radiation due to the effect of high-energy particles is not well known. Current radiation shielding technology, which would be viable for use in spacecraft, would not eliminate radiation risk. Similar to how a variety of shielding techniques are used every day by radiographers, again without full risk elimination, we need to explore and better understand the effect of deep space radiation in order to ensure the safety of those on future space missions.

The temperature effect of the muon component observed on A.I. Kuzmin cosmic ray spectrograph in Yakutsk

An estimation and accounting of a temperature effect in data of the complex of muon detectors of the Yakutsk cosmic ray spectrograph after A.I. Kuzmin are carried out. The results of determination of altitudinal distribution of the temperature from the database of world network of muon telescopes (MDDB), which are obtained using a model of the atmosphere developed in the National Centers for Environmental Prediction NCEP, are used. It is shown, that the vertical profiles of temperature distribution in the atmosphere that are presented in MDDB and the estimated temperature coefficients are allow qualitatively exclude the temperature effect from the data of registration of the muon component of secondary cosmic rays. The results of observation of the Yakutsk spectrograph and accounting of the temperature effect are presented in the Internet through the link http://www.ysn.ru/ipm.

Main scientific results of the DAMPE mission

The DArk Matter Particle Explorer (DAMPE) is a space mission, resulting from the collaboration of Chinese, Italian, and Swiss institutions. Since December 2015, DAMPE orbits at the altitude of 500 km and collects data regularly. The detector is made of four sub-detectors: top layers of plastic scintillators, a silicon-tungsten tracker, a deep BGO calorimeter (32 radiation lengths), and a bottom boron-doped scintillator to detect delayed neutrons. The main goal of the mission is the search for indirect signals of Dark Matter in the electron and photon spectra with energies up to 10 TeV. Furthermore DAMPE is studying cosmic charged and gamma radiation. The calorimeter depth and the large effective acceptance allow to measure cosmic ray fluxes in the range from 20 GeV up to hundreds of TeV. An overview of the latest results about electron and positron flux, light component (p+He) of charged cosmic rays, and gamma rays will be presented.

Galactic Cosmic Rays: The first detection of TeV gamma-rays from Red Dwarfs

The present point of view on the sources of cosmic rays in Galaxy considers explosions of supernovae as sources of these particles up to energies of 1017 eV. However, the experimental data obtained with Pamela, Fermi, AMS-02 spectrometers requires the existence of nearby sources of cosmic rays at distances less then 1 kpc from the solar system. These sources could explain such experimental data as the growth of the ratio of galactic positrons to electrons with increasing energy, the complex dependence of the exponent of the proton and alpha spectra from the energy of these particles, the appearance of an anomaly component in cosmic rays. We consider active dwarf stars as possible sources of galactic cosmic rays in the energy range up to 1014 eV. These stars produce powerful stellar flares. The generation of high-energy cosmic rays has to be accompanied by high-energy gamma-ray emission. Here we present the SHALON long-term observation data aimed at searching for gamma-ray emission above 800 GeV from active red dwarf stars. The data obtained during more than 10 years observations of the dwarf stars V962 Tau, V780 Tau, V388 Cas and V1589 Cyg were analyzed. The high-energy gamma-ray emission in the TeV energy range, mostly of the flaring type from the sources mentioned above, was detected. This result confirms that active dwarf stars are also the sources of high-energy galactic cosmic rays.

Main scientific results of the DAMPE mission

DAMPE (DArk Matter Particle Explorer) is a satellite-born experiment, resulting from the collaboration of Chinese, Italian, and Swiss institutions. Since December 2015, DAMPE flights at the altitude of 500 km and collects data smoothly. The detector is made of four sub-detectors: top layers of plastic scintillators, a silicon-tungsten tracker, a BGO calorimeter (32 radiation lengths), and a bottom boron-doped scintillator to detect delayed neutrons. The main goal of the experiment is the search for indirect signals of Dark Matter in the electron and photon spectra with energies up to 10 TeV. Furthermore DAMPE studies cosmic charged and gamma radiation. The calorimeter depth and the large acceptance allow to measure cosmic ray fluxes in the range from 20 GeV up to hundreds of TeV. An overview of the latest results about light component (p+He) of charged cosmic rays, gamma astronomy and electron and positron spectrum will be presented.

Peculiarities of soft gamma-radiation variations in the atmosphere

Soft gamma-radiation (20-400 keV) arriving from the atmosphere is being monitored by Polar Geophysical Institute (PGI), Apatity, Russia, at several stations located between Spitsbergen and the Causases. In Apatity and Spitsbergen, it has been carried out for ten years already. Detectors of the same type with output integral channels > 20 keV and > 100 keV are used. All the stations record increases in the gammaradiation flux, which are sometimes as high as 100%. These increases occur all the year round, in winter and summer and are recorded at all the stations. A great database on these increases has been used to analyze their characteristics. The detector used in Apatity, is integrated into a complex set carrying out monitoring over the main components of the secondary cosmic rays. According to the earlier experiments, no radioactive contamination has been found in precipitation. The integral and differential data have been analyzed to reveal the peculiarities of the phenomenon studied.

Investigation of abnormal absorption of cosmic-ray hadrons in lead calorimeters

A phenomenon of abnormally weak absorption of very high energy cosmic ray hadrons in thick lead blocks is discussed. This phenomenon was first observed in a Tien Shan high altitude experiment to study hadronic cores of extensive air showers (EAS) with a deep ionization calorimeter and encouraged researchers to introduce the hypothesis of the so-called long-flying or penetrating cosmic ray component. A similar effect was detected later with deep uniform lead X-ray emulsion chambers (XREC) at the Pamirs, which we discuss in detail. To establish the nature of the phenomenon we are have carried out dedicated experiments at the Tien Shan and at the Pamirs by exposing two-storey XRECs with large air gaps. According to detailed simulation of the chamber response, these experiments are very sensitive to the production of charmed hadrons in the forward kinematic region and can prove a hypothesis that the phenomenon under study can be explained on the assumption of very high values of charm particle production cross section at 〈ELab〉 ~ 75 TeV in the forward kinematic region at xLab≳ 0.1 which are near the upper limit of recent results of collider experiments, i.e., σpp→c¯c~ 8 mb. The same factor makes it possible to fit all the features of the experimental hadron absorption curve observed by means of deep uniform lead XRECs, including its bending at a depth of ~ 70 c.u.

A mobile complex to record several secondary cosmic rays components

The paper presents a research of the different components variations of the secondary cosmic rays (SCR). These are being monitored at the Cosmic Rays Laboratory, PGI, Apatity, using an integrated set based on the SCR basic components detectors. Also, besides stationary equipment, a mobile complex has been developed and made, which consists of a scintillation spectrometer, a charged component detector (CCD) based on the Geiger-Muller counters, and a neutron component detector (Е > 1 MeV) based on helium counters SNM-18. The mobile complex was put into operation in the early 2019. It operates in parallel with the basic equipment, recording SCRs. Small dimensions, effective energy consumption and ability to record data onto flash drives allows this complex to be used in SCR-monitoring in remote places, as well as on ships away at sea.

Towards a better estimation of energy and species of primary cosmic rays in the knee region with the Tibet hybrid experiment: Utilization of refined EAS lateral distributions

A new hybrid experiment (YAC-II+Tibet-III+MD) located at Yangbajing has started to improve the capability of explicit measurements of the cosmic-ray components (P, He, CNO, Fe, etc) at the knee energy region since 2014. Considering the different features of air shower development for different primary cosmic-ray nuclei, using a full Monte Carlo simulation, we modified the lateral distribution functions for proton-induced, helium-induced and iron-induced air showers, respectively. The results show that the air shower size of different nuclei obtained by the modified Nishimura-Kamata-Greisen function is consistent with the true shower size within 5% systematic errors. Furthermore, we studied the Extensive Air Shower age parameter determination from the lateral distribution functions of charged particles near the air shower core with the Tibet hybrid experiment. The derived age parameter can be well used to estimate the particle type of the incident primary cosmic rays.

Cherenkov water detector NEVOD and its further development

Abstract NEVOD is the first and the only in the world Cherenkov water detector (CWD) for investigations of all cosmic ray components on the Earth’s surface. Conception of quasispherical modules for detection of Cherenkov light in water from any direction with an equal efficiency is analyzed. Additional detectors for CWD and results of various investigations are discussed. The future development of the CWD NEVOD as a test facility for calibration of new optical modules for very large volume neutrino telescopes is considered.

Compact Star Clusters as Sources of Cosmic Rays and Neutrinos

The origin of cosmic rays is one of the most important questions in modern astrophysics. Leading world observatories are engaged in their search in our Galaxy and beyond. Current observations of bright sources of hard X-rays and gamma radiation require precise models of cosmic-ray accelerators and emission generation. Recent detection of astrophysical neutrinos with the energy exceeding 1015 eV achieved by the IceCube Neutrino Observatory and registration by the LOFAR observatory of the light cosmic-ray component at 1016–1017 eV have given rise to a wide discussion of whether its sources are galactic or extragalactic. H.E.S.S. observations of high-energy gamma-ray sources in compact massive clusters Westerlund 1 and Cl*1806-20 triggered a new search for the models of effective accelerators of high-energy cosmic rays, socalled galactic PeVatrons. In this paper, the properties of compact massive young stellar clusters as possible sources of cosmic rays, neutrinos, and gamma emission are discussed. We suppose that an expanding supernova remnant in a compact massive cluster is an effective cosmic-ray accelerator up to the energies of 1015 eV and beyond. Energy spectra of particles being accelerated in the system of colliding shocks generated by a supernova remnant interaction with nearby stellar winds have a broken power-law shape with a strong upturn around several teraelectronvolts and a cutoff energy at tens of petaelectronvolts. These sources provide the maximal emission flux at the maximal energies of the spectrum. Teraelectronvolt sources detected by H.E.S.S. could be related to supernova remnants in Westerlund 1 and Cl*1806-20 and be responsible for the 10% of the IceCube neutrino events. We have also shown that PeVatrons in the systems of colliding shocks can provide up to 80% of the light cosmic-ray component at the energies of 1016–1017 eV detected at the Earth.

Ion Composition of the Earth’s Radiation Belts in the Range from 100 keV to 100 MeV / nucleon $100\mbox{ MeV}/\mbox{nucleon}$ : Fifty Years of Research

Spatial, energy and angular distributions of ion fluxes in the Earth’s radiation belts (ERB) near the equatorial plane, at middle geomagnetic latitudes and at low altitudes are systematically reviewed herein. Distributions of all main ion components, from protons to Fe (including hydrogen and helium isotopes), and their variations under the action of solar and geomagnetic activity are considered. For ions with $Z\geq 2$ and especially for ions with $Z \geq 9$ , these variations are much more than for protons, and these have no direct connection with the intensity of magnetic storms ( $Z$ is the charge of the atomic nucleus with respect to the charge of the proton). The main physical mechanisms for the generation of ion fluxes in the ERB and the losses of these ions are considered. Solar wind, Solar Cosmic Rays (SCR), Galactic Cosmic Rays (GCR), and Anomalous component of Cosmic Rays (ACR) as sources of ions in the ERB are considered.

Origin of the light cosmic ray component below the ankle

The origin and nature of the ultrahigh energy cosmic rays remains a mystery. However, considerable progress has been achieved in past years due to observations performed by the Pierre Auger Observatory and Telescope Array. Above ${10}^{18}\text{ }\text{ }\mathrm{eV}$ the observed energy spectrum presents two features: a hardening of the slope at $\ensuremath{\sim}{10}^{18.6}\text{ }\text{ }\mathrm{eV}$, which is known as the ankle, and a suppression at $\ensuremath{\sim}{10}^{19.6}\text{ }\text{ }\mathrm{eV}$. The composition inferred from the experimental data, interpreted by using the current high energy hadronic interaction models, seems to be light below the ankle, showing a trend to heavier nuclei for increasing values of the primary energy. Also, the anisotropy information is consistent with an extragalactic origin of this light component that would dominate the spectrum below the ankle. Therefore, the models that explain the ankle as the transition from the galactic and extragalactic components are disfavored by present data. Recently, it has been proposed that this light component originates from the photodisintegration of more energetic and heavier nuclei in the source environment. The formation of the ankle can also be explained by this mechanism. In this work, we study in detail this general scenario, but in the context of the central region of active galaxies. In this case, the cosmic rays are accelerated near the supermassive black hole present in the central region of these types of galaxies, and the photodisintegration of heavy nuclei takes place in the radiation field that surrounds the supermassive black hole.

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.

The MONICA Experiment for Investigating the Ion Composition of Solar Cosmic Rays

The MONICA satellite-based experiment is described. In this experiment, fluxes of cosmic-ray ions from H to Ni are investigated near the Earth in the energy range of 10–300 MeV/nucleon. The main scientific objectives of the MONICA experiment are to measure the ion and isotope compositions and the energy spectra of solar cosmic rays for individual solar events and to study the evolution of these characteristics over time. The MONICA experiment will help to investigate the ion and isotope composition of the anomalous component of cosmic rays, galactic cosmic rays, and nuclear fluxes in the Earth’s radiation belt. Observations of ion fluxes will be carried out using the MONICA high-aperture multilayer semiconductor spectrometer–telescope installed on board a spacecraft with a low-Earth circular polar orbit at a height of approximately 600 km. This orbit will make it possible to perform the method for measuring the charge of ions with energies above 10 MeV/nucleon, which is based on the use of the Earth’s magnetic field as a particle- charge separator. The geometric factor of the instrument is 100 cm2 sr and the angular resolution is 1°.

Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station.

A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2GV to 3.3 TV based on 2.2×10^{6} events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. The spectral index rapidly hardens at high rigidities and becomes identical to the spectral indices of primary He, C, and O cosmic rays above ∼700 GV. We observed that the nitrogen flux Φ_{N} can be presented as the sum of its primary component Φ_{N}^{P} and secondary component Φ_{N}^{S}, Φ_{N}=Φ_{N}^{P}+Φ_{N}^{S}, and we found Φ_{N} is well described by the weighted sum of the oxygen flux Φ_{O} (primary cosmic rays) and the boron flux Φ_{B} (secondary cosmic rays), with Φ_{N}^{P}=(0.090±0.002)×Φ_{O} and Φ_{N}^{S}=(0.62±0.02)×Φ_{B} over the entire rigidity range. This corresponds to a change of the contribution of the secondary cosmic ray component in the nitrogen flux from 70% at a few GV to <30% above 1TV.

Cosmic Ray Muons of High and Ultrahigh Energies

Muons are the main component of cosmic rays on the Earth’s surface and underground. The energy spectrum and angular distribution of muons in the atmosphere are related both to the mechanisms of their generation and to the basic characteristics of the primary cosmic rays—their energy spectrum and mass composition. Changes in the muon flux underground are determined by muon energy losses, and its measurements allow muon interaction processes to be studied. The history of extensive cosmic-ray muon investigations covers many decades. A retrospective overview of important directions of cosmic ray muon studies is presented, and analysis of the main experiments and results is given. Special attention is paid to the “muon puzzle”, that is, the muon excess increasing with the energy of primary particles, and to possible ways of solving it.

Cooler and smoother – the impact of cosmic rays on the phase structure of galactic outflows

We investigate the impact of cosmic rays (CRs) on galactic outflows from a multi-phase interstellar medium with solar neighbourhood conditions. The three-dimensional magneto-hydrodynamical simulations include CRs as a relativistic fluid in the advection-diffusion approximation. The thermal and chemical state of the ISM is computed with a non-equilibrium chemical network. We find that CRs (injected with 10 \% of the supernova energy) efficiently support the launching of outflows and strongly affect their phase structure. Outflows leaving the midplane are denser ($\rho \sim 10^{-26}\,\mathrm{g\,cm}^{-3}$), colder ($\sim 10^4\,\mathrm{K}$), and slower ($\sim 30\,\mathrm{km\,s}^{-1}$) if CRs are considered in addition to thermal SNe. The CR supported outflows are also smoother, in particular at larger heights ($> 1\,\mathrm{kpc}$ above the midplane) without the direct impact of SN explosions. Approximately $5\% - 25\%$ of the injected CR energy is lost via hadronic cooling. Smaller diffusion coefficients lead to slightly larger hadronic losses but allow for steeper CR pressure gradients, stronger outflows and larger accelerations. Up to a height of $z \sim1\,\mathrm{kpc}$ there are large volumes in approximate pressure equilibrium between thermal and CR component. At larger altitudes the CR pressure is $10-100$ times as large as the thermal counterpart. More than $\sim 1\,\mathrm{kpc}$ away from the midplane, CRs provide the dominant gas acceleration mechanism.

Improving the discrimination capability of heavy nuclei based on direct Cherenkov light

The accurate measurement of individual species of cosmic rays (CRs) is very important to solve the problem of their origin. CR spectra with energies > 100 TeV can be evaluated only by detecting extensive air showers on the ground. Thus, identifying the primary components of CRs depends highly on hadronic interaction models. Direct Cherenkov light (DC-light) emitted by the primary components of CRs prior to first interaction in the atmosphere can be used to identify such primary components. The intensity of DC-light is proportional to the square of the charge of CRs primary components and independent of the hadronic interaction model. In this study, we investigate the characteristics of DC-light and its ability to discriminate heavy nuclei (iron and MgAlSi) from CR components by using the Wide Field-of-view Cherenkov Telescope Array of the Large High-Altitude Air-Shower Observatory (LHAASO-WFCTA) in the energy range between 50 TeV and 500 TeV. Results suggest that DC-light can be used in the LHAASO to improve the reconstruction accuracy of CR heavy components.

On the knee of Galactic cosmic rays in light of sub-TeV spectral hardenings**Supported by National Key Research and Development Program of China (2016YFA0400200), the National Natural Science Foundation of China (11635011, 11761141001, 11663006, 11722328) and the 100 Talents program of Chinese Academy of Sciences

More than fifty years after the discovery of the knee in the cosmic ray (CR) spectra, its physical origin remains a mystery. This is partly due to the ambiguity of the energy spectra of individual components. Recently, direct measurements from several space experiments found significant spectral hardenings of CR nuclei at ∼200 GV. A joint modeling of the direct and indirect measurements may help to understand the experimental systematics and the physics of the knee. In this work, we update the phenomenological “poly-gonato” model to include the spectral hardenings, with a changing spectral index of γ + β · log E. This modification gives a reasonable description of the CR spectra in a wide energy range. However, the fits to different data sets give different results. We find that the fit to the AMS-02 and CREAM data slightly favors a relatively low energy knee of the light components. In such a case, the expected all-particle spectra under-shoot the data, which may require an extra component of CRs. The fits to AMS-02 data and the light component (H+He) data from the Tibet ASγ/ARGO-YBJ/WFCTA and KASCADE experiments give consistent results with the all-particle spectra. We further propose a possible physical realization of such a “modified poly-gonato” model of spectral hardenings by means of spatially-dependent diffusion of CRs. We find reasonably good agreement between the model predictions and the data for CR spectra, the secondary-to-primary ratios, and the amplitude of anisotropies.