Cosmic-Ray Scattering and Streaming in Compressible Magnetohydrodynamic Turbulence

By Huirong Yan, A. Lazarian. 2004

234 citations recorded by the source corpus.

Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for revisions in the picture of cosmic-ray transport. In this paper we use recently obtained scaling laws for MHD modes to obtain the scattering frequency for cosmic rays. Using quasi-linear theory, we calculate gyroresonance with MHD modes (Alfvénic, slow, and fast) and transit-time damping (TTD) by fast modes. We provide calculations of cosmic-ray scattering for various phases of interstellar medium with realistic interstellar turbulence driving that is consistent with the velocity dispersions observed in diffuse gas. We account for the turbulence cutoff arising from both collisional and collisionless damping. We obtain analytical expressions for diffusion coefficients that enter the Fokker-Planck equation describing cosmic-ray evolution. We obtain the scattering rate and show that fast modes provide the dominant contribution to cosmic-ray scattering for the typical interstellar conditions in spite of the fact that fast modes are subjected to damping. We determine how the efficiency of the scattering depends on the characteristics of ionized media, e.g., plasma β. We calculate the range of energies for which the streaming instability is suppressed by the ambient MHD turbulence.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/06de375e52d4c31dfad8306e6a5e51138a898704

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic-Ray Transport (2005, background): “The region of the cosmic ray halo is the most “safe” in this sense (Yan & Lazarian 2004).”
Cluster Mergers and Non-Thermal Phenomena: A Statistical Magneto-Turbulent Model (2004, methodology): “The cascade time of fast MS waves at the wavenumber k is given by (e.g. Yan & Lazarian 2004): τkk(k) ∼ vM kv2k ∼ vMρ k2Wk (B2) so that the diffusion coefficient in equation (19) is given by: Dkk ∼ k 2 τkk ∼ v 2 A vM k4Wk 2WB .”
Solar winds driven by nonlinear low‐frequency Alfvén waves from the photosphere: Parametric study for fast/slow winds and disappearance of solar winds (2005, background): “In such circumstances, the friction due to ion-neutral collisions might be important in the dissipation of Alfve´n waves [Lazarian et al., 2004; Yan and Lazarian, 2004 ].”
Compressible turbulence in galaxy clusters: physics and stochastic particle re-acceleration (2007, background): “⋆⋆ Γe/ωr has a maximum value ≈ 0.2 †† The wandering of the magnetic field at scales l ≤ lA is discussed in Yan & Lazarian (2004).”
Impulsive Phase Flare Energy Transport by Large-Scale Alfvén Waves and the Electron Acceleration Problem (2007, methodology): “There is a vast literature on the development of magnetic turbulence, but Yan & Lazarian (2004) provide useful expressions for the relevant timescales.”
Dust Dynamics in Compressible Magnetohydrodynamic Turbulence (2004, background): “8 This dependencem akesthetreatm entofdam ping m orecom plicated iftaking into account eld linewandering (see Yan & Lazarian 2004).”
The 511 keV emission from positron annihilation in the Galaxy (2010, methodology): “Using numerical simulation, the magnetosonic cascade has been found to keep its isotropy along the whole range of spatial scales (Yan and Lazarian, 2004).”
Acceleration of primary and secondary particles in galaxy clusters by compressible MHD turbulence: from radio haloes to gamma-rays (2010, background): “These modes were also identified as major scattering agent for Galactic cosmic rays (Yan & Lazarian 2002, 2004).”