DAMPING OF MAGNETOHYDRODYNAMIC TURBULENCE IN PARTIALLY IONIZED PLASMA: IMPLICATIONS FOR COSMIC RAY PROPAGATION

Journal Article · Mon Aug 01 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/826/2/166· OSTI ID:22679599

Xu, Siyao ^[1]; Yan, Huirong ^[2]

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1. Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)
2. Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

We study the damping processes of both incompressible and compressible magnetohydrodynamic (MHD) turbulence in a partially ionized medium. We start from the linear analysis of MHD waves, applying both single-fluid and two-fluid treatments. The damping rates derived from the linear analysis are then used in determining the damping scales of MHD turbulence. The physical connection between the damping scale of MHD turbulence and the cutoff boundary of linear MHD waves is investigated. We find two branches of slow modes propagating in ions and neutrals, respectively, below the damping scale of slow MHD turbulence, and offer a thorough discussion of their propagation and dissipation behavior. Our analytical results are shown to be applicable in a variety of partially ionized interstellar medium (ISM) phases and the solar chromosphere. The importance of neutral viscosity in damping the Alfvenic turbulence in the interstellar warm neutral medium and the solar chromosphere is demonstrated. As a significant astrophysical utility, we introduce damping effects to the propagation of cosmic rays in partially ionized ISM. The important role of turbulence damping in both transit-time damping and gyroresonance is identified.

• OSTI ID: 22679599
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 826; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALFVEN WAVES
ASTROPHYSICS
CHROMOSPHERE
COSMIC RADIATION
COSMIC RAY PROPAGATION
DAMPING
ELECTRIC UTILITIES
FLUIDS
INTERSTELLAR SPACE
MAGNETOHYDRODYNAMICS
PLASMA
TURBULENCE
VISCOSITY