scholarly journals Monitoring and forecasting of great radiation hazards for spacecraft and aircrafts by online cosmic ray data

2005 ◽  
Vol 23 (9) ◽  
pp. 3019-3026 ◽  
Author(s):  
L. I. Dorman
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Radiation Hazard ◽  
Personal Health ◽  
The Sun ◽  
Positive Signal ◽  
Radiation Hazards ◽  
Monitoring And Forecasting ◽  
High Level ◽  
High Energy Particles

Abstract. We show that an exact forecast of great radiation hazard in space, in the magnetosphere, in the atmosphere and on the ground can be made by using high-energy particles (few GeV/nucleon and higher) whose transportation from the Sun is characterized by a much bigger diffusion coefficient than for small and middle energy particles. Therefore, high energy particles come from the Sun much earlier (8-20 min after acceleration and escaping into solar wind) than the main part of smaller energy particles (more than 30-60 min later), causing radiation hazard for electronics and personal health, as well as spacecraft and aircrafts. We describe here principles of an automatic set of programs that begin with "FEP-Search", used to determine the beginning of a large FEP event. After a positive signal from "FEP-Search", the following programs start working: "FEP-Research/Spectrum", and then "FEP-Research/Time of Ejection", "FEP-Research /Source" and "FEP-Research/Diffusion", which online determine properties of FEP generation and propagation. On the basis of the obtained information, the next set of programs immediately start to work: "FEP-Forecasting/Spacecrafts", "FEP-Forecasting/Aircrafts", "FEP-Forecasting/Ground", which determine the expected differential and integral fluxes and total fluency for spacecraft on different orbits, aircrafts on different airlines, and on the ground, depending on altitude and cutoff rigidity. If the level of radiation hazard is expected to be dangerous for high level technology or/and personal health, the following programs will be used "FEP-Alert/Spacecrafts", "FEP-Alert/ Aircrafts", "FEP-Alert/Ground".

Composition and spectra of primary cosmic-ray electrons and nuclei above 10 10 eV

1975 ◽  
Vol 277 (1270) ◽  
pp. 349-363 ◽  
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Energy Spectra ◽  
Average Lifetime ◽  
Interstellar Space ◽  
Interstellar Matter ◽  
Electromagnetic Interactions ◽  
Nuclear Species ◽  
The Galaxy ◽  
High Energy Particles

Recent experiments have extended the knowledge of the flux and energy spectra of individual cosmic-ray components to much higher energies than had previously been accessible. Both electron and nuclear components show a behaviour at high energy which is unexpected, and which carries information regarding the sources and the propagation of particles between sources and observer. Electromagnetic interactions which are suffered by the electrons in interstellar space should steepen their spectrum, a steepening that would reveal the average lifetime a cosmic-ray particle spends in the galaxy. Measurements up to 1000 GeV show no such steepening. It was discovered that the composition of the nuclear species which is now measured up to 100 GeV/nucleon changes with energy. This change indicates traversal of less interstellar matter by the high energy particles than by those of lower energy. We discuss the experimental evidence and its implication.

scholarly journals Cosmic-ray propagation around the Sun: investigating the influence of the solar magnetic field on the cosmic-ray Sun shadow

2020 ◽  
Vol 633 ◽  
pp. A83
Author(s):  
J. Becker Tjus ◽  
P. Desiati ◽  
N. Döpper ◽  
H. Fichtner ◽  
J. Kleimann ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Solar Magnetic Field ◽  
Cosmic Ray ◽  
High Energy ◽  
High Solar Activity ◽  
The Sun ◽  
Theoretical Understanding

The cosmic-ray Sun shadow, which is caused by high-energy charged cosmic rays being blocked and deflected by the Sun and its magnetic field, has been observed by various experiments, such as Argo-YBJ, Tibet, HAWC, and IceCube. Most notably, the shadow’s size and depth was recently shown to correlate with the 11-year solar cycle. The interpretation of such measurements, which help to bridge the gap between solar physics and high-energy particle astrophysics, requires a solid theoretical understanding of cosmic-ray propagation in the coronal magnetic field. It is the aim of this paper to establish theoretical predictions for the cosmic-ray Sun shadow in order to identify observables that can be used to study this link in more detail. To determine the cosmic-ray Sun shadow, we numerically compute trajectories of charged cosmic rays in the energy range of 5−316 TeV for five different mass numbers. We present and analyze the resulting shadow images for protons and iron, as well as for typically measured cosmic-ray compositions. We confirm the observationally established correlation between the magnitude of the shadowing effect and both the mean sunspot number and the polarity of the magnetic field during the solar cycle. We also show that during low solar activity, the Sun’s shadow behaves similarly to that of a dipole, for which we find a non-monotonous dependence on energy. In particular, the shadow can become significantly more pronounced than the geometrical disk expected for a totally unmagnetized Sun. For times of high solar activity, we instead predict the shadow to depend monotonously on energy and to be generally weaker than the geometrical shadow for all tested energies. These effects should become visible in energy-resolved measurements of the Sun shadow, and may in the future become an independent measure for the level of disorder in the solar magnetic field.

Solar Physics: Overview

2020 ◽  
Author(s):  
E.R. Priest
Keyword(s):  
Solar Physics ◽  
Theoretical Models ◽  
High Energy ◽  
The Sun ◽  
Dynamo Action ◽  
Current Time ◽  
Definitive Answer ◽  
Year 2000 ◽  
High Energy Particles ◽  
The Magnetic Field

Solar physics is one of the liveliest branches of astrophysics at the current time, with many major advances that have been stimulated by observations from a series of space satellites and ground-based telescopes as well as theoretical models and sophisticated computational experiments. Studying the Sun is of key importance in physics for two principal reasons. Firstly, the Sun has major effects on the Earth and on its climate and space weather, as well as other planets of the solar system. Secondly, it represents a Rosetta stone, where fundamental astrophysical processes can be investigated in great detail. Yet, there are still major unanswered questions in solar physics, such as how the magnetic field is generated in the interior by dynamo action, how magnetic flux emerges through the solar surface and interacts with the overlying atmosphere, how the chromosphere and corona are heated, how the solar wind is accelerated, how coronal mass ejections are initiated and how energy is released in solar flares and high-energy particles are accelerated. Huge progress has been made on each of these topics since the year 2000, but there is as yet no definitive answer to any of them. When the answers to such puzzles are found, they will have huge implications for similar processes elsewhere in the cosmos but under different parameter regimes.

An exact solution of cosmic ray modulation problem in a stationary composite heliosphere model

2019 ◽  
Vol 491 (4) ◽  
pp. 5826-5842
Author(s):  
Yuriy L Kolesnyk ◽  
Boris A Shakhov ◽  
Pavol Bobik ◽  
Marian Putis
Keyword(s):  
Exact Solution ◽  
Cosmic Ray ◽  
High Energy ◽  
Physical Processes ◽  
Modern Problem ◽  
Cosmic Ray Modulation ◽  
Initial Spectrum ◽  
Particle Speed ◽  
Particle Propagation ◽  
High Energy Particles

ABSTRACT A new theoretical approach to describe the physical processes of energy particle propagation is proposed. This approach is based on the analytically iterative method for solving closed cosmic ray (CR) modulation problems, which was proposed by Shakhov and Kolesnyk. First, we have applied the approach on a simple model of the heliosphere, wherein the diffusion coefficients κ for each region of CR modulation are constants. This approach produced a very good matching of the obtained solution and also provided a numerical solution and an analytical solution. Finally, a modern problem of CR modulation in a stationary composite model of the heliosphere was considered. This model includes an environment that contains adjacent spherically symmetric regions with different modes of propagation of the solar wind (SW) speed for each layer. The CR scattering is due to different factors for each layer of the environment, as characterized by relevant κ values that simultaneously have dependence on the momentum of the particle p and the particle speed $\upsilon$, i.e. $\kappa \propto p\upsilon$. The local interstellar spectra (LISs) are given by a power-law unmodulated spectrum with the slope of the initial spectrum α, i.e. LIS ∝ p−α. An exact solution of the problem of CR modulation for low-energy particles and high-energy particles was first derived and qualitatively compared against the Voyager 1 data.

scholarly journals Selective Effects in Cosmic Rays Induced by Coulombian Interactions with Finite Temperature Plasmas

1981 ◽  
Vol 94 ◽  
pp. 365-366
Author(s):  
J. Pérez-Peraza ◽  
S. S. Trivedi
Keyword(s):  
Cosmic Rays ◽  
Energy Levels ◽  
Cosmic Ray ◽  
High Energy ◽  
Energy Losses ◽  
Deceleration Rate ◽  
Acceleration Rate ◽  
Charge States ◽  
High Energy Particles

The role of Coulombian energy losses in cosmic ray physics is generally over simplified by using the Bethe-Block formulation which does not depend explicitly on the temperature of the medium. The role of low energy particles is usually neglected, as a result of the over estimation of losses when the temperature of the medium is ignored. A deep analysis of Coulombian losses may raise the importance of these particles in the dynamics of the Galaxy. In fact, the deceleration of these particles is determined by charge interchange processes with the target ions and electrons, which energy dependence is roughly the inverse of ionisation losses. Even high energy particles may be subject to this kind of deceleration if the temperature is very high. The consideration of Coulombian losses through all energy ranges with explicit dependence on the temperature has been discussed by Perez and Lara (1979): a fully ionized medium of hydrogen has been assumed to prevail in most of cosmic ray sources. One kind of the implications is the determination of particle composition. It is claimed that a given kind of ion is preferentially accelerated or depleted depending on whether the acceleration is higher or lower than the deceleration rate at the beginning of the acceleration of thermal material. Species which undergo depletion are accelerated only if their energy is higher than that for which both rates are equated (Ec,E′c and E′c′) in such a way that only those of the hot tails of their thermal distributions are effectively accelerated. These will appear depleted relative to other species which are free accelerated because their deceleration rates at low energies are lower than the acceleration rate. It can be noted in the next figures, that if both rates would not intersect at the beginning of the acceleration, they would not join at higher energies because the acceleration rate grows faster with energy than the deceleration rate. Three arbitrary acceleration rates are used for illustration: Fermi-2nd order (αβW), Betatron or adiabatic heating (αβ2W) and shock wave acceleration (αW), where α, β and W are the efficiency, the particles velocity and the total energy per nucleon respectively. In Fig. 1 it can be seen that this selective acceleration relative to Coulombian losses is defined at different energy levels depending on the kind of acceleration involved. Since the main effect of the temperature on the losses at the beginning of the acceleration is through the local charge states of the ions, the sequence of energy losses among different species is highly assorted. This is translated in a great amount of possibilities of particle enhancements and depletions according to the temperature of the source and the kind of acceleration operating therein. If particles under go acceleration in a fully stripped state, the sequence of losses at all energy levels is such that the heavy elements are depleted in relation with the lighter ones; same is the situation, what-ever the initial charge state, for high energy particles in the range of ionisation. It may be concluded, on basis to the observational enhancement of heavy cosmic rays, that hot regions are not likely sources, and that acceleration initiates from thermal energies. On Fig. 2 it is illustrated the enhancement of Fe over 0 in solar flare conditions, on basis to the charge states as given by Jordan (1969). If α < 2.71 s−1 both elements would be depleted, whereas if α>3.45 s−1 both would be preferentially accelerated.

scholarly journals Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Hiromasa Suzuki ◽  
Aya Bamba ◽  
Ryo Yamazaki ◽  
Yutaka Ohira
Keyword(s):  
Power Law ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Spectral Shape ◽  
X Ray ◽  
Galactic Cosmic Ray ◽  
High Energy Particles ◽  
Accelerated Particles

Abstract In the current decade, GeV/TeV gamma-ray observations of several supernova remnants (SNRs) have implied that accelerated particles are escaping from their acceleration sites. However, when and how they escape from the SNR vicinities are yet to be understood. Recent studies have suggested that the particle escape might develop with thermal plasma ages of the SNRs. We present a systematic study on the time evolution of particle escape using thermal X-ray properties and gamma-ray spectra using 38 SNRs associated with GeV/TeV gamma-ray emissions. We conducted spectral fittings on the gamma-ray spectra using exponential cutoff power-law and broken power-law models to estimate the exponential cutoff or the break energies, both of which are indicators of particle escape. Plots of the gamma-ray cutoff/break energies over the plasma ages show similar tendencies to those predicted by analytical/numerical calculations of particle escape under conditions in which a shock is interacting with thin interstellar medium or clouds. The particle escape timescale is estimated as ∼100 kyr from the decreasing trends of the total energy of the confined protons with the plasma age. The large dispersions of the cutoff/break energies in the data may suggest an intrinsic variety of particle escape environments. This might be the cause of the complicated Galactic cosmic ray spectral shape measured on Earth.

scholarly journals THE SEARCH FOR NEUTRINO SOURCES BEYOND THE SUN

1996 ◽  
Vol 11 (19) ◽  
pp. 3393-3413 ◽  
Author(s):  
S. BARWICK ◽  
F. HALZEN ◽  
P.B. PRICE
Keyword(s):  
Particle Physics ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Neutrino Telescope ◽  
The Sun ◽  
Electromagnetic Showers ◽  
Electron Neutrinos ◽  
Neutrino Astronomy ◽  
Near Future

It is hoped that in the near future, neutrino astronomy, born with the identification of thermonuclear fusion in the sun and the particle processes controlling the fate of a nearby supernova, will reach throughout and beyond our galaxy and make measurements relevant to cosmology, astrophysics, cosmic-ray physics and particle physics. The construction of a high-energy neutrino telescope requires a huge volume of very transparent, deeply buried material, such as ocean water or ice, which acts as the medium for detecting the particles. The AMANDA1 muon and neutrino telescope, now operating four strings of photomultiplier tubes buried in deep ice at the South Pole, is scheduled to be expanded to a ten-string array. The data collected over the first two years cover the three basic modes in which such instruments are operated: (i) the burst mode which monitors the sky for supernovae, (ii) the detection of electromagnetic showers initiated by PeV-energy cosmic electron neutrinos, and (iii) muon trajectory reconstruction for neutrino and gamma-ray astronomy. We speculate on the possible architectures of kilometer-scale instruments, using early data as a guideline.

Local high-energy particles measurements for detecting primary cosmic-ray variations: application for soil moisture estimation

2020 ◽  
Author(s):  
Luca Stevanato ◽  
Gabriele Baroni ◽  
Cristiano Fontana ◽  
Marcello Lunardon ◽  
Sandra Moretto ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Real Time ◽  
Land Surface ◽  
Spatial Scales ◽  
Cosmic Ray ◽  
High Energy ◽  
Canopy Interception ◽  
Local Conditions ◽  
Proportional Counters ◽  
High Energy Particles

&lt;p&gt;In the last decade the measurement of secondary cosmic ray neutrons has been established as a unique approach for intermediate scale observation of land surface hydrogen pools. Originally developed for soil moisture measurements, it has shown also promising applications for snow, biomass and canopy interception. The approach relies on the correlation between natural neutron background as created by cosmic-ray fluxes and local hydrogen pools. Due to the specific capabilities of the neutrons to move in air, the signal detected by the sensor installed above-ground is sensitive to an area of hundreds of meters providing a new perspective for proximal land-surface observations. The measurements are generally performed based on moderated proportional counters filled with Helium-3 or Boron and the moderation is created by adding shielding material (mostly polyethylene) around the counter.&lt;/p&gt;&lt;p&gt;The signal is affected by the temporal variability of the incoming neutron fluxes. At first, the variability of neutron fluxes is due to solar activities. The neutrons are further attenuated by the mass of the air and air humidity.&lt;/p&gt;&lt;p&gt;Specific corrections have been proposed to account for these effects. Air pressure and humidity corrections rely on local measurements that could be easily collected. Incoming correction due to solar cosmic-ray fluctuation is based on a worldwide network monitoring station (NMDB). This network provides online access to their data in real-time. However, this approach showed some limitations in region where incoming fluxes could be not representative of local conditions introducing errors that could be relevant for the estimation of the targeted variable. In addition, it requires the need of post-processing of the data resulting in some difficulties to provide, e.g., soil moisture observations in real-time.&lt;/p&gt;&lt;p&gt;In the present contribution, we show the results of tests conducted on an alternative commercial sensor based on scintillators. The new probe has the capability to identify different neutron energies ranges and gamma-rays providing new opportunities for hydrological observations at different spatial scales. In addition, the probe is sensitive to high energy particles that can be used for correcting the neutron signal by the variations of primary cosmic-ray flux. We present results from the comparison of the new probe with standard proportional counters and neutron monitor database in a long-term outdoor case study. We show how the use of local high energy particles is a practical alternative to account atmospheric corrections and overcome the limitation of using data from NMDB.&lt;/p&gt;

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