scholarly journals Diffusion of cosmic rays in MHD turbulence

2021 ◽  
Author(s):  
Siyao Xu
Keyword(s):  
Cosmic Rays ◽  
Mhd Turbulence

COSMIC RAYS AND MHD TURBULENCE GENERATION IN INTERSTELLAR GIANT MOLECULAR CLOUDS

2016 ◽  
Vol 824 (2) ◽  
pp. 89 ◽  
Author(s):  
R. Schlickeiser ◽  
M. Caglar ◽  
A. Lazarian
Keyword(s):  
Cosmic Rays ◽  
Molecular Clouds ◽  
Giant Molecular Clouds ◽  
Mhd Turbulence ◽  
Turbulence Generation

scholarly journals On the Nature of Magnetohydrodynamic Turbulence in the Interstellar Medium

1990 ◽  
Vol 140 ◽  
pp. 153-154
Author(s):  
V.N. Fedorenko
Keyword(s):  
Cosmic Rays ◽  
Shock Waves ◽  
Interstellar Medium ◽  
Weak Shock ◽  
Mhd Waves ◽  
Mhd Turbulence ◽  
Magnetohydrodynamic Turbulence ◽  
Extended Spectrum

Various mechanisms of creation of the extended spectrum of MHD turbulence in the interstellar medium are reviewed. Within the scales 1014 cm ≲ L ≲ 1019 cm the turbulence mostly consists of the ensemble of weak shock waves. At 1012 cm ≲ L ≲ 1014 cm the principle mechanism is generation of MHD waves by cosmic rays.

scholarly journals Diffusion of Cosmic Rays in MHD Turbulence with Magnetic Mirrors

2021 ◽  
Vol 923 (1) ◽  
pp. 53
Author(s):  
Alex Lazarian ◽  
Siyao Xu
Keyword(s):  
Cosmic Rays ◽  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Mirror Reflection ◽  
Mhd Turbulence ◽  
Magnetic Mirrors ◽  
Parallel Diffusion ◽  
Angle Scattering ◽  
Small Pitch ◽  
New Type

Abstract As the fundamental physical process with many astrophysical implications, the diffusion of cosmic rays (CRs) is determined by their interaction with magnetohydrodynamic (MHD) turbulence. We consider the magnetic mirroring effect arising from MHD turbulence on the diffusion of CRs. Due to the intrinsic superdiffusion of turbulent magnetic fields, CRs with large pitch angles that undergo mirror reflection, i.e., bouncing CRs, are not trapped between magnetic mirrors, but move diffusively along the turbulent magnetic field, leading to a new type of parallel diffusion, i.e., mirror diffusion. This mirror diffusion is in general slower than the diffusion of nonbouncing CRs with small pitch angles that undergo gyroresonant scattering. The critical pitch angle at the balance between magnetic mirroring and pitch-angle scattering is important for determining the diffusion coefficients of both bouncing and nonbouncing CRs and their scalings with the CR energy. We find nonuniversal energy scalings of diffusion coefficients, depending on the properties of MHD turbulence.

scholarly journals Trapping of Cosmic Rays in MHD Turbulence

2020 ◽  
Vol 894 (1) ◽  
pp. 63 ◽  
Author(s):  
Siyao Xu ◽  
Alex Lazarian
Keyword(s):  
Cosmic Rays ◽  
Mhd Turbulence

scholarly journals Interstellar and Intracluster Tunnels and Acceleration of High-Energy Cosmic Rays

1981 ◽  
Vol 94 ◽  
pp. 73-74
Author(s):  
A. Ferrari ◽  
A. Masani
Keyword(s):  
Cosmic Rays ◽  
Supernova Remnants ◽  
High Energy ◽  
Interstellar Space ◽  
Mhd Turbulence ◽  
High Energy Cosmic Rays ◽  
Physical Mechanisms ◽  
The Galaxy ◽  
Image Position ◽  
Galactic Sources

The present evidence about the origin of high-energy cosmic rays is that two ranges exist: one below 1018 eV related with galactic sources, and one up to 1020 eV, corresponding to extragalactic processes (Kiràly et al. 1979). However the continuity of the spectrum indicates that the physical mechanisms must be correlated. In the global energetics the spectral range above 1012 eV is irrelevant and the bulk of CR energy is actually provided by supernovae, pulsars, X-ray binaries, etc. in the Galaxy. Nevertheless none of these objects seems capable of producing CR above 1015 eV/nucleon. We have investigated the possibility that the acceleration at higher energies is statistical, taking place over a hierarchy of scales. A model has been developed in terms of the quasi-linear theory of particle acceleration by MHD turbulence. Cosmic rays with ≲1015 eV/nucleon injected by single sources into interstellar space undergo momentum diffusion by stockastic interaction with long wavelength MHD perturbations; small wavelength modes provide pitchangle scatterings. These MHD perturbations, Alfvèn and last magnetosonic waves, are generated by the dynamic interaction of supernova remnants with the interstellar medium. From observations (Jokipii 1977), the range of possible wavelengths extends from the proton gyroradius to the size of the so-called “superbubbles”, up to 100 pc, with a power-law spectrum. Correspondingly acceleration is efficient up to 1018 eV/nucleon; in fact for B 10−3 + 10−5 G, n = 0.01 ÷ 1 cm−3 and L = 0.1 ÷ 100 pc, we find that the acceleration timescale (ε = eBL is the maximum allowed energy) is always shorter than the time scales of losses and turbulent structure lifetimes; α = 3.5 ÷ 4 is the speciral index of turbulent modes. Contrary to the original Ferm i mechanism, in this theory the time scale for acceleration up to any energy ε is fixed by the final phase, previous steps being negligible.

Shielding Space Explorers From Cosmic Rays

Space Weather ◽  
2005 ◽  
Vol 3 (8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Eugene N. Parker
Keyword(s):  
Cosmic Rays

The anomalous entry of low-rigidity solar cosmic rays into the geomagnetic field

1963 ◽  
Vol 68 (19) ◽  
pp. 5327 ◽  
Author(s):  
S.-I. Akasofu ◽  
W. C. Lin ◽  
J. A. Van Allen
Keyword(s):  
Cosmic Rays ◽  
Geomagnetic Field ◽  
Solar Cosmic Rays

Cosmic rays

AccessScience ◽  
2015 ◽  
Keyword(s):  
Cosmic Rays

Cloud formation may be linked to cosmic rays

Nature ◽  
2011 ◽  
Author(s):  
Geoff Brumfiel
Keyword(s):  
Cosmic Rays ◽  
Cloud Formation
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