Effects Of Cosmic Rays Research Articles

Influence of cosmic rays on environmental ecosystems

AbstractIt is presented a model to consider the effect of high energy cosmic rays on three types of terrestrial ecosystem: coastal macroalgae, lakes, and forests. The model includes insights into muon dosimetry based in the stopping power of muons while traveling in water and soft biological tissues. It is shown that a muon from secondary cosmic rays could deposit in cells an energy much higher than that deposited by ultraviolet photons coming from the Sun. Consequently, drastic short‐term reductions of photosynthesis are obtained if energetic astrophysical phenomena such as gamma ray bursts and neutron star mergers happen in our astronomical neighborhood, while radiational solar storms also cause considerable inhibition of photosynthesis.

Structure and evolution of interstellar carbonaceous dust. Insights from the laboratory

A large fraction of interstellar carbon is locked up in solid grains. The nature, origin and evolution of these grains have been investigated for decades. A combination of observations, models and experiments indicates that carbonaceous dust is mostly made of a mixture of grains composed almost exclusively of carbon and hydrogen. They have different proportions of aliphatic and aromatic structures, and a variable H/C ratio. Their sizes can vary typically between the nm and the hundreds of nm. Carbonaceous grains are largely formed in the envelopes of carbon rich asymptotic giant branch (AGB) stars and evolve in the interstellar medium, where they can be transformed or destroyed by the effects of hydrogen atoms, UV radiation, cosmic rays or shock waves from supernovae. Surviving grains eventually enter dense clouds and participate in the cloud collapse leading to star formation, closing thus their lifecycle. Within this general picture, there are doubts and issues that cannot be solved just by observation and modeling and require laboratory work. In this article we provide an overview of the development and present state of the field indicating open problems and debated questions. We stress recent experimental progress in the understanding of dust formation, both in circumstellar envelopes and the cold interstellar medium, and also in the energetic processing of dust analogs, that points to a possible top down chemistry in the diffuse medium, and especially in photon irradiated regions.

Evaluating the effects of low-dose simulated galactic cosmic rays on murine hippocampal-dependent cognitive performance.

Space exploration has advanced substantially over recent decades and plans to increase the duration of deep space missions are in preparation. One of the primary health concerns is potential damage to the central nervous system (CNS), resulting in loss of cognitive abilities and function. The majority of ground-based research on space radiation-induced health risks has been conducted using single particle simulations, which do not effectively model real-world scenarios. Thus, to improve the safety of space missions, we must expand our understanding of the effects of simulated galactic cosmic rays (GCRs) on the CNS. To assess the effects of low-dose GCR, we subjected 6-month-old male BALB/c mice to 50 cGy 5-beam simplified GCR spectrum (1H, 28Si, 4He, 16O, and 56Fe) whole-body irradiation at the NASA Space Radiation Laboratory. Animals were tested for cognitive performance with Y-maze and Morris water maze tests 3 months after irradiation. Irradiated animals had impaired short-term memory and lacked spatial memory retention on day 5 of the probe trial. Glial cell analysis by flow cytometry showed no significant changes in oligodendrocytes, astrocytes, microglia or neural precursor cells (NPC's) between the sham group and GCR group. Bone marrow cytogenetic data showed a significant increase in the frequency of chromosomal aberrations after GCR exposure. Finally, tandem mass tag proteomics identified 3,639 proteins, 113 of which were differentially expressed when comparing sham versus GCR exposure (fold change > 1.5; p < 0.05). Our data suggest exposure to low-dose GCR induces cognitive deficits by impairing short-term memory and spatial memory retention.

Ionospheric D Region: VLF‐Measured Electron Densities Compared With Rocket‐Based FIRI‐2018 Model

AbstractGround‐based very low frequency (VLF) radio propagation in the Earth‐ionosphere waveguide has enabled extensive electron number densities in the D region of the Earth's ionosphere to be determined, by day typically below heights of 70–80 km and by night in the height range ∼75–90 km. Many rocket‐based electron density measurements have also been reported in the literature from ∼60 km upwards using current probes, and radio propagation at a few MHz between the rocket and ground. Recently these rocket measurements have been summarized, and supplemented with D region production‐loss modeling, giving rise to a near global model named FIRI‐2018 (Faraday‐International Reference Ionosphere) which provides electron number densities as functions of height, latitude (&lt;60°), solar zenith angle and F10.7 cm solar flux. These rocket‐based electron density values are here compared with corresponding values from VLF measurements, by day at a low‐latitude (∼20°) and a high mid‐latitude (∼55°), and by night mainly at mid‐latitudes. At night the average agreement (over 75–90 km) is remarkably good. By day, at low latitude the agreement is also fairly good (in the common height range ∼60–75 km), with the changes with solar zenith angle being moderately comparable. For daytime high mid‐latitudes, the agreement is less satisfactory, particularly at the lowest common altitudes, with the VLF measurements showing the expected effects of cosmic rays much more than the rocket‐based values. Overall, we find that the D region description in the FIRI‐2018 model is a significant advance on the earlier International Reference Ionosphere (IRI‐2016) model.

Low dose space radiation-induced effects on the mouse retina and blood-retinal barrier integrity

The health risk of flight condition-triggered ocular injury and neurodegeneration has long been a concern. Spaceflight missions will likely expose the astronauts and experiment payloads to greater radiation levels compared to those encountered on the Earth. Knowledge about the susceptibility to adverse effects from low doses of radiation during space missions is very limited. Our present study aims to investigate and compare the effects of whole-body simulated galactic cosmic rays (GCR) on blood-retinal barrier (BRB) integrity, oxidative stress, and apoptosis in the retina of male and female mouse models. Six-month-old male and female CD1 mice were either sham irradiated or received whole-body 5-ion simulated GCR exposure at a dose of 0.5 Gy. At four months following irradiation, mice were euthanized and ocular tissues were collected for histochemical analysis. BRB integrity was evaluated with biomarkers aquaporin-4 (AQP-4), a water channel protein, tight junction (TJ) Zonula occludens-1 (ZO-1), and adhesive molecule, platelet endothelial cell adhesion molecule-1 (PECAM-1). A significantly increased expression of AQP-4 was observed in the retina following GCR exposure compared to controls (p < 0.05) with more pronounced changes observed in the female mice over males. There was also a significant increase in the expression of PECAM-1 and a decrease in the expression of ZO-1 in the retina of irradiated groups compared to controls. Immunochemical analysis revealed enhanced immunoreactivity for oxidative biomarker, 4-hydroxynonenal (4-HNE) in the retina following radiation exposure. Significant increases in the numbers of apoptotic cells were also documented in the retina of irradiated male and female mice compared to controls (p < 0.05). Our study revealed that exposure to low-dose ionizing radiation induced cellular oxidative damage that may alter retina structure and BRB integrity. The results also demonstrate some sex-related differences in the radiation response. Further studies are needed to investigate the factors that contribute to gender- or genetic related variabilities in ocular changes to radiation exposure for a better understanding of the mechanisms of spaceflight-induced ocular findings.

The Effects of Cosmic Rays on the Chemistry of Dense Cores

Cosmic rays are crucial to the chemistry of molecular clouds and their evolution. They provide essential ionizations, dissociations, heating, and energy to the cold, dense cores. As cosmic rays pierce through clouds they are attenuated and lose energy, which leads to a dependency on the column density of a system. The detailed effects these particles have on the central regions still need to be fully understood. Here, we revisit how cosmic rays are treated in the UCLCHEM chemical modeling code by including both ionization rate and H2 dissociation rate dependencies alongside the production of cosmic ray induced excited species and we study in detail the effects of these treatments on the chemistry of pre-stellar cores. We find that these treatments can have significant effects on chemical abundances, up to several orders of magnitude, depending on the physical conditions. The ionization dependency is the most significant treatment influencing chemical abundances through the increased presence of ionized species, grain desorptions, and enhanced chemical reactions. Comparisons to chemical abundances derived from observations show the new treatments reproduce these observations better than the standard handling. It is clear that more advanced treatments of cosmic rays are essential to chemical models and that including this type of dependency provides more accurate chemical representations.

Diffuse GeV emission in the field of HESS J1912+101 revisited

We have analyzed 12 years of Fermi Large Area Telescope data toward the HESS J1912+101 region. With the latest source catalog and diffuse background models, a γ-ray excess is detected with a significance of ~8σ in the energy range of above 10 GeV. It has been argued that the diffuse GeV emission in the vicinity of HESS J1912+101 are from an extended pulsar wind nebula powered by PSR J1913+1011 and also that the hard GeV emission above 10 GeV stems from the shell-type supernova remnant and is connected with the TeV emissions. Different from previous works, our analysis indicates that the H2 spatial template is preferred over the other spatial templates, suggesting that the diffuse emission component spatially correlates with the dense molecular gas. This spatial correlation favors a hadronic emission scenario, although a leptonic origin cannot be ruled out. In the hadronic scenario, the parent proton spectrum can be described by a power-law function with an index of α = 2.36 ± 0.16. Above 50 GeV, there is no emission, and the upper limits reveal a spectral cutoff or break in the parent proton spectrum that can be explained as propagation effects of cosmic rays. We argue that the parent protons may come from the candidate supernova remnant HESS J1912+101 or the young massive star cluster Mc20.

Cryopreserved Stem Cells Incur Damages Due To Terrestrial Cosmic Rays Impairing Their Integrity Upon Long-Term Storage

Stem cells have the capacity to ensure the renewal of tissues and organs. They could be used in the future for a wide range of therapeutic purposes and are preserved at liquid nitrogen temperature to prevent any chemical or biological activity up to several decades before their use. We show that the cryogenized cells accumulate damages coming from natural radiations, potentially inducing DNA double-strand breaks (DSBs). Such DNA damage in stem cells could lead to either mortality of the cells upon thawing or a mutation diminishing the therapeutic potential of the treatment. Many studies show how stem cells react to different levels of radiation; the effect of terrestrial cosmic rays being key, it is thus also important to investigate the effect of the natural radiation on the cryopreserved stem cell behavior over time. Our study showed that the cryostored stem cells totally shielded from cosmic rays had less DSBs upon long-term storage. This could have important implications on the long-term cryostorage strategy and quality control of different cell banks.

Method of Wavelet-Decomposition to Research Cosmic Ray Variations: Application in Space Weather

Since their discovery, cosmic rays have been an integral part of the development of fundamental physics, from the discovery of radiation coming to the Earth from outer space and the identification of high-energy particles in it, as well as new fundamental symmetries in the laws of nature, to the knowledge of residual matter and magnetic fields in interstellar space. Cosmic rays are used in a number of fundamental and applied research in solar-terrestrial physics and are important in the research of the near-Earth space processes. Cosmic ray variations observed on the Earth’s surface are an integral result of various solar, heliospheric, magnetospheric and atmospheric phenomena. The most significant changes in cosmic ray parameters are caused by coronal mass ejections and subsequent changes in the parameters of the interplanetary magnetic field and solar wind. Therefore, the study of cosmic rays makes it possible to obtain valuable information about the processes in the near-Earth space and in the Earth’s magnetosphere during disturbed periods. This article proposes a method for analyzing cosmic ray variations. It is based on the use of wavelet data decomposition operations and their combination with threshold functions. By using adaptive thresholds, the operations for detecting anomalous changes in data and for suppressing the noise were developed. Anomalies in cosmic rays can cause radiation hazard for astronauts, radio communication failures, as well as malfunctions in satellites, leading to the loss of orientation and destruction. Therefore, the task of timely diagnostics of anomalies is urgent. The paper describes the algorithms for the implementation of the method and shows their application in the space weather problem. We used data from the network of ground stations of neutron monitors. The efficiency of the method for detecting abnormal changes of different amplitudes and durations is shown. Application of the method made it possible to detect clearly and to evaluate Forbush effects in cosmic rays, which precede the onset of magnetic storms of various nature and strength.

On the relationship of power lines outages caused by thunderstorms with Forbush decreases of cosmic rays

It is known that power lines outages often occur during thunderstorms. Here are the results of comparing of power lines outages in Yakutia from 2012 to 2018 with the database of Forbush-Storm events. This database contains information on geomagnetic storms and Forbush-decreases of cosmic rays from 1996 to 2018. There are 3 classes of the events: if these two ground-based manifestations of solar wind disturbances occur simultaneously (Forbush with Storm, F+S) or separately (Forbush without Storm, F-S and Storm without Forbush, S-F). For 7 years in the summer time, 73 power lines outages associated with thunderstorms were recorded. It is shown that in 56 cases these outages occurred simultaneously with (F-S) class, 16 – with (F+S) class, and only in 1 case lightning outages were not associated with Forbush-Storm events (-F-S). In 19 cases of (S-F) class, not a single lightning outage was recorded. This means that lightning outages on power lines are mainly associated with decreases in the cosmic rays intensity, and during geomagnetic storms, power transmission disruptions occur when storms are simultaneous with Forbush-decreases of cosmic rays. Apparently, this indicates the significance of the effect of cosmic rays on atmospheric electricity, and it is more significant than the effect of geomagnetic storms.

Gravitational instability in radiative molecular clouds including cosmic ray diffusion and ion Larmor radius corrections

ABSTRACT The effects of cosmic ray (CR) diffusion and finite Larmor radius (FLR) corrections have been studied on the linear gravitational instability of thermally conducting plasmas typically in the H ii regions of molecular clouds. The hydrodynamic fluid–fluid approach is considered for interacting CRs with gravitating, magnetized, and thermally conducting gas in molecular clouds. The magnetohydrodynamic fluid model is formulated considering CR pressure gradients, CR diffusion, and radiative and FLR effects in terms of particle Larmor radius. The dispersion relation of the gravitational instability is analytically derived using the normal mode analysis, and the effects of CRs and FLR corrections have been discussed in longitudinal and transverse modes. It is observed that in the absence of CRs, the FLR effects (magnetic viscosity) reduce the growth rate for wavenumber smaller than a critical value, and above it gets increased. However, the growth rate is strongly suppressed in the presence of combined CRs and FLR effects. The individual behaviour of FLR effects is observed to destabilize the growth rate of the gravitational instability in the presence of CR effects. The CR pressure decreases the growth rates of the gravitational and thermal instabilities, whereas parallel CR diffusion enhances the growth rate of the gravitational instability. The Jeans length of the gravitating gas cloud gets increased due to an increase in the CR-to-gas pressure ratio. It is found that the gravitational collapse of the system is supported by high-energy (above knee) CR particles with the Larmor radii comparable to the cloud size. The present results have been applied to understand the role of CRs and FLR corrections on the gravitational collapse in the H ii regions of molecular clouds.

Diagnostics for Electromagnetic Conditions in the Heliosphere by Cosmic Ray Effects

Diagnostics for Electromagnetic Conditions in the Heliosphere by Cosmic Ray Effects

How to create an artificial magnetosphere for Mars

If humanity is ever to consider substantial, long-term colonization of Mars, the resources needed are going to be extensive. For a long-term human presence on Mars to be established, serious thought would need to be given to terraforming the planet. One major requirement for such terraforming is having the protection of a planetary magnetic field - which Mars currently does not have. The Earth's magnetosphere helps protect the planet from the potential sterilizing effects of cosmic rays and also helps retain the atmosphere, which would otherwise by stripped by large solar storms as they pass over the planet. Mars does have small patches of remnant surface magnetic field, but these are localized in the southern hemisphere and are not of sufficient size or magnitude to protect the planet or a colony.In this article we explore comprehensively for the first time, the practical and engineering challenges that affect the feasibility of creating an artificial magnetic field capable of encompassing Mars. This includes the concerns that define the design, where to locate the magnetic field generator and possible construction strategies. The rationale here is not to justify the need for a planetary magnetosphere but to put figures on the practicalities so as to be able to weigh the pros and cons of the different engineering approaches.The optimum solution proposed is completely novel, although inspired by natural situations and fusion plasma techniques. The solution with the lowest power, assembly and mass is to create an artificial charged particle ring (similar in form to a ‘radiation belt’), around the planet possibly formed by ejecting matter from one of the moons of Mars (in a fashion similar to that which forms the Jupiter-Io plasma torus), but using electromagnetic and plasma waves to drive a net current in the ring(s) that results in an overall magnetic field.With a new era of space exploration underway, this is the time to start thinking about these new and bold future concepts and to begin filling strategic knowledge gaps. Furthermore, the principles explored here are also applicable to smaller scale objects like manned spacecraft, space stations or moon bases, which would benefit from the creation of protective mini-magnetospheres.

Метод автоматической коррекции данных нейтронного монитора на осадки в виде снега в реальном времени

We have carried out an experimental study of the influence of precipitation in the form of snow on measurements of the neutron flux intensity near Earth's surface. We have examined the state of the snow cover and its density, and found out that the density depends on the depth of the snow cover. Using the experimental results, we estimate the neutron absorption path in the snow. Changes in snow cover by 10–12 cm at a depth of 80 cm are shown to cause variations in the monitor count rate with an amplitude of 0.9 %. At the snow depth of 80 cm, the neutron monitor count rate decreases by about 8 %. The observed variations should be attributed to the meteorological effects of cosmic rays. The absorption coefficient of neutrons in the snow was also found from the correlation between the count rate of the neutron monitor and the amount of snow above the detector. We propose a real-time correction of the neutron monitor data for precipitation in the form of snow. For this purpose, we implement continuous monitoring of the amount of snow cover. The monitoring is provided by a snow meter made using a laser rangefinder module. We discuss the results obtained.

Method of automatic correction of neutron monitor data for precipitation in the form of snow in real time

We have carried out an experimental study of the influence of precipitation in the form of snow on measurements of the neutron flux intensity near Earth's surface. We have examined the state of the snow cover and its density, and found out that the density depends on the depth of the snow cover. Using the experimental results, we estimate the neutron absorption path in the snow. Changes in snow cover by 10–12 cm at a depth of 80 cm are shown to cause variations in the monitor count rate with an amplitude of 0.9 %. At the snow depth of 80 cm, the neutron monitor count rate decreases by about 8 %. The observed variations should be attributed to the meteorological effects of cosmic rays. The absorption coefficient of neutrons in the snow was also found from the correlation between the count rate of the neutron monitor and the amount of snow above the detector. We propose a real-time correction of the neutron monitor data for precipitation in the form of snow. For this purpose, we implement continuous monitoring of the amount of snow cover. The monitoring is provided by a snow meter made using a laser rangefinder module. We discuss the results obtained.

Modulation Effects in Cosmic Rays during a Period of Anomalously Low Solar Activity

Modulation Effects in Cosmic Rays during a Period of Anomalously Low Solar Activity

Simulations of systematic effects arising from cosmic rays in the LiteBIRD space telescope, and effects on the measurements of CMB B-modes

Systematic effects arising from cosmic rays have been shown to be a significant threat to space telescopes using high-sensitivity bolometers. The LiteBIRD space mission aims to measure the polarised Cosmic Microwave Background with unprecedented sensitivity, but its positioning in space will also render it susceptible to cosmic ray effects. We present an end-to-end simulator for evaluating the expected scale of cosmic ray effects on the LiteBIRD space mission, which we demonstrate on a subset of detectors on the 166 GHz band of the Low Frequency Telescope. The simulator couples the expected proton flux at L2 with a model of the thermal response of the LFT focal plane and the electrothermal response of its superconducting detectors, producing time-ordered data which is projected into simulated sky maps and subsequent angular power spectra.

Characterisation of cosmic ray induced noise events in AstroSat-CZT imager

The Cadmium Zinc Telluride (CZT) Imager onboard AstroSat consists of pixelated CZT detectors, which are sensitive to hard X-rays above 20 keV. The individual pixels are triggered by ionising events occurring in them, and the detectors operate in a self-triggered mode, recording each event separately with information about its time of incidence, detector co-ordinates, and channel that scales with the amount of ionisation. The detectors are sensitive not only to photons from astrophysical sources of interest, but also prone to a number of other events like background X-rays, cosmic rays, and noise in detectors or the electronics. In this work, a detailed analysis of the effect of cosmic rays on the detectors is made and it is found that cosmic rays can trigger multiple events which are closely packed in time (called ‘bunches’). Higher energy cosmic rays, however, can also generate delayed emissions, a signature previously seen in the PICsIT detector on-board INTEGRAL. An algorithm to automatically detect them based on their spatial clustering properties is presented. Residual noise events are examined using examples of Gamma Ray Bursts as target sources.

The Effects of Cosmic and Ultraviolet Rays on Yeast and Seeds

Cosmic and ultraviolet rays are pervasive and often difficult to avoid, for atmospheric pollution has caused an increase in harmful radiation reaching the Earth's surface due to the rapid depletion of the ozone layer. Because the deterioration of the ozone layer is a recent phenomenon, it is important to understand the rays’ effects on the DNA of organisms. It is also an area of interest in the field of astrobiology as humans begin to consider the possibility of long-term exposure of crops to these types of radiation in prolonged space travel. The Bioballoon project, described in this paper, was a payload for a weather balloon built to expose samples of yeast and seeds to cosmic and ultraviolet rays in the middle to upper stratosphere. After plating the yeast and planting the seeds, it was found that although cosmic and UV radiation appeared to induce mutations in yeast genes, they do not produce significant phenotypic differences in plants.

Dynamical Effects of Cosmic Rays on the Medium Surrounding Their Sources

Abstract Cosmic rays (CRs) leave their sources mainly along the local magnetic field; in doing so they excite both resonant and nonresonant modes through streaming instabilities. The excitation of these modes leads to enhanced scattering and in turn to a large pressure gradient that causes the formation of bubbles of gas, CRs, and self-generated magnetic fields expanding into the interstellar medium. By means of hybrid particle-in-cell simulations, we show that, by exciting the nonresonant instability, CRs excavate a cavity around their source where the diffusivity is strongly suppressed. This finding invalidates the so far largely adopted flux-tube assumption, under which particles move along magnetic lines even in the nonlinear regime. This phenomenon is general and is expected to occur around any sufficiently powerful CR source in the Galaxy. Our results might provide a physical explanation of the numerous claims of suppressed CR diffusion around Galactic sources such as supernova remnants, pulsar wind nebulae, and stellar clusters.