Astrophysical hydromagnetic turbulence

TL;DR

This paper reviews recent advances in astrophysical hydromagnetic turbulence, discussing models, magnetic field generation, cosmic ray interactions, and the effects of turbulence anisotropy on astrophysical phenomena.

Contribution

It provides a comprehensive overview of the Goldreich--Sridhar model, its extensions, and their implications for cosmic rays and magnetic field generation in astrophysics.

Findings

Goldreich--Sridhar model is widely accepted for MHD turbulence

Turbulent transport processes are affected by anisotropy and inhomogeneity

Magnetic field generation and cosmic ray dynamics are influenced by turbulence properties

Abstract

Recent progress in astrophysical hydromagnetic turbulence is being reviewed. The physical ideas behind the now widely accepted Goldreich--Sridhar model and its extension to compressible magnetohydrodynamic turbulence are introduced. Implications for cosmic ray diffusion and acceleration is being discussed. Dynamo-generated magnetic fields with and without helicity are contrasted against each other. Certain turbulent transport processes are being modified and often suppressed by anisotropy and inhomogeneities of the turbulence, while others are being produced by such properties, which can lead to new large-scale instabilities of the turbulent medium. Applications of various such processes to astrophysical systems are being considered.