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We show that the large-scale cosmic ray anisotropy at ~10 TeV can be explained by a modified Compton-Getting effect in the magnetized flow field of old supernova remnants. This approach suggests an optimum energy scale for detecting the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 P. L. Biermann , J. K. Becker , E. -S. Seo , M. Mandelartz

A model is introduced, in which the irregularity spectrum of the Galactic magnetic field beyond the dissipation length scale is first a Kolmogorov spectrum $k^{-5/3}$ at small scales $\lambda \, = \, 2 \pi/k$ with $k$ the wave-number, then…

High Energy Astrophysical Phenomena · Physics 2015-11-16 P. L. Biermann , L. I. Caramete , A. Meli , B. N. Nath , E. -S. Seo , V. de Souza , J. Becker Tjus

We investigate how cosmic rays (CRs) affect thermal and hydrostatic stability of circumgalactic (CGM) gas, in simulations with both CR streaming and diffusion. Local thermal instability can be suppressed by CR-driven entropy mode…

Astrophysics of Galaxies · Physics 2023-05-25 Tsun Hin Navin Tsung , S. Peng Oh , Chad Bustard

Cosmic ray (CR)-driven instabilities play a decisive role during particle acceleration at shocks and CR propagation in galaxies and galaxy clusters. These instabilities amplify magnetic fields and modulate CR transport so that the…

High Energy Astrophysical Phenomena · Physics 2021-03-03 Mohamad Shalaby , Timon Thomas , Christoph Pfrommer

Observations of interstellar scintillations at radio wavelengths reveal a Kolmogorov-like scaling of the electron density spectrum with a spectral slope of -5/3 over six decades in wavenumber space. A similar turbulent density spectrum in…

Space Physics · Physics 2015-05-13 Dastgeer Shaikh , G. P. Zank

Motivated by the discovery of the non-thermal Fermi bubble features both below and above the Galactic plane, we investigate a scenario in which these bubbles are formed through Galacto-centric outflow. Cosmic rays (CR) both diffusing and…

High Energy Astrophysical Phenomena · Physics 2017-01-11 Andrew M. Taylor , Gwenael Giacinti

The nature of cosmic ray (CR) transport in the Milky Way remains elusive. The predictions of current micro-physical CR transport models in magneto-hydrodynamic (MHD) turbulence are drastically different from what is observed. These models…

We investigate the dynamical impact of cosmic rays in cosmological simulations of galaxy formation using adaptive-mesh refinement simulations of a $10^{12}$ solar mass halo. In agreement with previous work, a run with only our standard…

Astrophysics of Galaxies · Physics 2015-06-23 Munier Salem , Greg L. Bryan , Cameron Hummels

New measurements of galaxy clustering and background radiations provide improved constraints on the isotropy and homogeneity of the Universe on large scales. In particular, the angular distribution of radio sources and the X-Ray Background…

Astrophysics · Physics 2009-10-16 Kelvin K. S. Wu , Ofer Lahav , Martin J. Rees

The Galactic cosmic ray (GCR) intensity has been postulated by others to vary cyclically with a peak to valley ratio of ~3:1, as the Solar System moves from the Spiral Arm to the Inter-Arm regions of the Galaxy. These intensities have been…

Solar and Stellar Astrophysics · Physics 2015-06-15 T. Sloan , A. W. Wolfendale

A major uncertainty in understanding the transport and feedback of cosmic-rays (CRs) within and beyond our Galaxy lies in the unknown CR scattering rates, which are primarily determined by wave-particle interaction at microscopic…

High Energy Astrophysical Phenomena · Physics 2022-04-06 Xue-Ning Bai

The growth of magneto-hydrodynamic fluctuations relevant to cosmic ray confinement in and near their sources, and the effects of local plasma conditions is revisited. We consider cases where cosmic rays penetrate a medium which may contain…

High Energy Astrophysical Phenomena · Physics 2021-02-10 B. Reville , G. Giacinti , R. Scott

The cosmic ray current-driven (CRCD) instability, predicted by Bell (2004), consists of non-resonant, growing plasma waves driven by the electric current of cosmic rays (CRs) that stream along the magnetic field ahead of both relativistic…

Astrophysics · Physics 2011-02-11 Mario A. Riquelme , Anatoly Spitkovsky

Starburst galaxies are efficient $\gamma$-ray producers, because their high supernova rates generate copious cosmic ray (CR) protons, and their high gas densities act as thick targets off which these protons can produce neutral pions and…

High Energy Astrophysical Phenomena · Physics 2020-02-26 Mark R. Krumholz , Roland M. Crocker , Siyao Xu , A. Lazarian , M. T. Rosevear , Jasper Bedwell-Wilson

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence,…

Space Physics · Physics 2015-05-14 Dastgeer Shaikh , G. P. Zank

We reported the gamma-ray observation towards the giant molecular cloud Polaris Flare. Together with the dust column density map, we derived the cosmic ray density and spectrum in this cloud. Compared with the CR measured locally, the CR…

High Energy Astrophysical Phenomena · Physics 2021-12-08 Zhi-wei Cui , Rui-zhi Yang , Bing Liu

The diffusive transport in two-dimensional incompressible turbulent fields is investigated with the aid of high-quality direct numerical simulations. Three classes of turbulence spectra that are able to capture both short and long-range…

Fluid Dynamics · Physics 2023-03-24 D. I. Palade , L. M. Pomârjanschi , M. Ghită

Cosmic ray (CR) propagation is controlled by scattering in turbulent magnetic fields in space. In general, diffusive propagation is governed by pitch-angle diffusion in phase space. In this study, pitch-angle diffusion in the local…

High Energy Astrophysical Phenomena · Physics 2026-05-26 Huirong Yan , Siqi Zhao , Ming Zhang

Cosmic ray propagation is determined by the properties of interstellar turbulence. The multiphase nature of interstellar medium (ISM) and diversity of driving mechanisms give rise to spatial variation of turbulence properties. Meanwhile,…

High Energy Astrophysical Phenomena · Physics 2021-09-21 Huirong Yan

Recently, Zhang & Liu (2024) proposed a turbulent convection model for multiscale anisotropies of cosmic rays (CRs), with an assumption of isotropic diffusion such that the anisotropies are statistically isotropic. However, this assumption…

High Energy Astrophysical Phenomena · Physics 2025-06-26 Yiran Zhang , Siming Liu
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