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We calculate the diffusion coefficients of charged cosmic rays (CR) propagating in regular and turbulent magnetic fields. If the magnetic field is dominated by an isotropic turbulent component, we find that CRs reside too long in the…

High Energy Astrophysical Phenomena · Physics 2018-07-24 G. Giacinti , M. Kachelriess , D. V. Semikoz

We introduce a novel diffusion model for the propagation of cosmic rays (CRs) that incorporates an anisotropic diffusion tensor of a general form within a realistically modeled large-scale Galactic magnetic field. The parameters of the…

High Energy Astrophysical Phenomena · Physics 2025-07-22 V. D. Borisov , V. O. Yurovsky , I. A. Kudryashov

The 11-year and 22-year modulation of galactic cosmic rays (GCRs) in the inner heliosphere are studied using a numerical model developed by Qin and Shen in 2017. Based on the numerical solutions of Parker's transport equations, the model…

Space Physics · Physics 2018-02-28 Z. -N. Shen , G. Qin

Galactic cosmic rays (CRs) inside the heliosphere are affected by solar modulation. To investigate this phenomenon and its underlying physical mechanisms, we have performed a data-driven analysis of the temporal dependence of the CR proton…

High Energy Astrophysical Phenomena · Physics 2021-07-21 Emanuele Fiandrini , Nicola Tomassetti , Bruna Bertucci , Federico Donnini , Maura Graziani , Behrouz Khiali , Alejandro Reina Conde

Galactic cosmic-ray (GCR) flux short-term variations ($<$1 month) in the inner heliosphere are mainly associated with the passage of high-speed solar wind streams (HSS) and interplanetary (IP) counterparts of coronal mass ejections (ICMEs).…

Earth and Planetary Astrophysics · Physics 2020-12-07 Catia Grimani , Andrea Cesarini , Michele Fabi , Federico Sabbatini , Daniele Telloni , Mattia Villani

Numerical modeling of galactic cosmic rays (GCRs) penetration through the heliosphere to the vicinity of the Sun is considered. Galactic cosmic rays are charged particles with energies exceeding 10 MeV/nucl., originating from far beyond the…

High Energy Astrophysical Phenomena · Physics 2025-09-04 D. A. Shestakov , V. V. Izmodenov

The north-south (NS) anisotropy of galactic cosmic rays (GCRs) is dominated by a diamagnetic drift flow of GCRs in the interplanetary magnetic field (IMF), allowing us to derive key parameters of cosmic-ray propagation, such as the density…

Solar and Stellar Astrophysics · Physics 2024-12-17 M. Kozai , Y. Hayashi , K. Fujii , K. Munakata , C. Kato , N. Miyashita , A. Kadokura , R. Kataoka , S. Miyake , M. L. Duldig , J. E. Humble , K. Iwai

When entering the heliosphere, Galactic cosmic rays (GCRs) are influenced by magnetic turbulence and Solar wind disturbances, which cause the so-called "solar modulation" effect. Understanding the time-dependent relationship between the…

High Energy Astrophysical Phenomena · Physics 2019-08-06 Bruna Bertucci , Emanuele Fiandrini , Behrouz Khiali , Nicola Tomassetti

Dynamically, cosmic rays with energies above about one GeV/nucleon may be important agents of galaxy evolution. Their pressures compare with the thermal and magnetic ones impacting galactic gas accretion, fountains and galactic outflows,…

High Energy Astrophysical Phenomena · Physics 2022-05-18 A. Nuñez-Castiñeyra , I. A. Grenier , F. Bournaud , Y. Dubois , F. R. Kamal Youssef , P. Hennebelle

The ability to predict times of greater galactic cosmic ray (GCR) fluxes is important for reducing the hazards caused by these particles to satellite communications, aviation, or astronauts. The 11-year solar cycle variation in cosmic rays…

Solar and Stellar Astrophysics · Physics 2015-06-15 Simon R Thomas , Mathew J Owens , Mike Lockwood

One of the unsolved problems in cosmic ray (CR) physics is the small radial gradient of the gamma-ray intensity compared to the inferred CR source distribution in the Galactic disk. In diffusive CR propagation models the most natural…

Astrophysics · Physics 2007-05-23 D. Breitschwerdt , V. Dogiel , H. J. V"olk

We study changes of the galactic cosmic ray (GCR) intensity for the ending period of the solar cycle 23 and the beginning of the solar cycle 24 using neutron monitors experimental data. We show that an increase of the GCR intensity in 2009…

Solar and Stellar Astrophysics · Physics 2015-04-06 M. V. Alania , R. Modzelewska , A. Wawrzynczak

We develop a fully three dimensional numerical code describing the diffusion of cosmic rays in the Milky Way. It includes the nuclear spallation chain up to Oxygen, and allows the study of various cosmic ray properties, such as the CR age,…

Astrophysics of Galaxies · Physics 2017-11-10 David Benyamin , Ehud Nakar , Tsvi Piran , Nir J. Shaviv

The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a time-dependent modulation model. By introducing recent theoretical advances in the transport coefficients in the model,…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Rex Manuel , Stefan Ferreira , Marius Potgieter

We present the observation of a charge-sign dependent solar modulation of galactic cosmic rays (GCRs) with the CALorimetric Electron Telescope onboard the International Space Station over 6 yr, corresponding to the positive polarity of the…

Understanding the transport of energetic cosmic rays belongs to the most challenging topics in astrophysics. Diffusion due to scattering by electromagnetic fluctuations is a key process in cosmic-ray transport. The transition from a…

High Energy Astrophysical Phenomena · Physics 2020-09-02 P. Reichherzer , J. Becker Tjus , E. G. Zweibel , L. Merten , M. J. Pueschel

We study the role of drift effect in the temporal changes of the anisotropy of galactic cosmic rays (GCRs) and the influence of the sector structure of the heliospheric magnetic field on it. We analyze the GCRs anisotropy in the Solar Cycle…

Solar and Stellar Astrophysics · Physics 2021-04-26 R. Modzelewska , K. Iskra , W. Wozniak , M. Siluszyk , M. V. Alania

The dependence of the cosmic ray intensity on Galactocentric distance is known to be much less rapid than that to be thought-to-be sources: supernova remnants. This is an old problem ('the radial gradient problem') which has led to a number…

Astrophysics of Galaxies · Physics 2015-12-23 Anatoly Erlykin , Arnold Wolfendale , Vladimir Dogiel

Cosmic rays may have contributed to the start of life on Earth. Here, we investigate the evolution of the Galactic cosmic ray spectrum at Earth from ages $t = 0.6-6.0\,$Gyr. We use a 1D cosmic ray transport model and a 1.5D stellar wind…

Solar and Stellar Astrophysics · Physics 2020-10-28 D. Rodgers-Lee , A. A. Vidotto , A. M. Taylor , P. B. Rimmer , T. P. Downes

Measuring the cosmic ray flux over timescales comparable to the age of the solar system, $\sim 4.5\,$Gyr, could provide a new window on the history of the Earth, the solar system, and even our galaxy. We present a technique to indirectly…

High Energy Physics - Phenomenology · Physics 2020-12-01 Johnathon R. Jordan , Sebastian Baum , Patrick Stengel , Alfredo Ferrari , Maria Cristina Morone , Paola Sala , Joshua Spitz