Turbulent dynamo in a weakly ionized medium
arXiv:1901.02893 · doi:10.3847/1538-4357/aafbe8
Abstract
The small-scale turbulent dynamo is an important process contributing to the cosmic magnetization. In partially ionized astrophysical plasmas, the dynamo growth of magnetic energy strongly depends on the coupling state between ions and neutrals and the ion-neutral collisional damping effect. A new damping stage of turbulent dynamo in a weakly ionized medium was theoretically predicted by Xu \& Lazarian (2016). By carrying out a 3D two-fluid dynamo simulation, here we for the first time numerically confirmed the physical conditions and the linear-in-time growth of magnetic field strength of the damping stage of dynamo. The dynamo-amplified magnetic field has a characteristic length as the damping scale, which increases with time and can reach the injection scale of turbulence after around eight largest eddy-turnover times given sufficiently low ionization fraction and weak initial magnetic field. Due to the weak coupling between ions and neutrals, most turbulent energy carried by neutrals cannot be converted to the magnetic energy, resulting in a relatively weak magnetic field at the end of dynamo. This result has important implications for the growth of magnetic fields in the partially ionized interstellar medium and shock acceleration of Galactic cosmic rays.
Accepted for publication in ApJ; 11 pages, 5 figures
References in corpus (43)
- Astrophysical magnetic fields and nonlinear dynamo theory
- Reconnection in a Weakly Stochastic Field
- The Millennium Arecibo 21-CM Absorption Line Survey. II. Properties of the Warm and Cold Neutral Media
- Simulations of Incompressible MHD Turbulence
- Compressible Magnetohydrodynamic Turbulence: mode coupling, scaling relations, anisotropy, new regime and astrophysical implications
- Supernova remnants: the X-ray perspective
- Simulations of MHD Turbulence in a Strongly Magnetized Medium
- Diffuse Galactic Emission from Spinning Dust Grains
- Numerical Tests of Fast Reconnection in Weakly Stochastic Magnetic Fields
- Compressible Sub-Alfvenic MHD turbulence in Low-beta Plasmas
- Compressible MHD Turbulence in Interstellar Plasmas
- Simulations of nonhelical hydromagnetic turbulence
- Second Order Accurate Schemes for Magnetohydrodynamics With Divergence-Free Reconstruction
- Fine Structures of Shock of SN 1006 with the Chandra Observation
- A Spatial and Spectral Study of Nonthermal Filaments in Historical Supernova Remnants: Observational Results with Chandra
- Multidimensional HLLE Riemann solver; Application to Euler and Magnetohydrodynamic Flows
- A Two-dimensional HLLC Riemann Solver for Conservation Laws : Application to Euler and MHD Flows
- Magnetic Field Structure and Stochastic Reconnection in a Partially Ionized Gas
- Magnetohydrodynamic waves in solar partially ionized plasmas: two-fluid approach
- Turbulence-induced magnetic fields and the structure of Cosmic Ray modified shocks
- Is nonhelical hydromagnetic turbulence peaked at small scales?
- Growth of Magnetic Fields Induced by Turbulent Motions
- Collisions, magnetization, and transport coefficients in the lower solar atmosphere
- The Generation of Magnetic Fields Through Driven Turbulence
- Universal Nonlinear Small-Scale Dynamo
- Chandra Observations of A Galactic Supernova Remnant Vela Jr.: A New Sample of Thin Filaments Emitting Synchrotron X-Rays
- New Regime of MHD Turbulence: Cascade Below Viscous Cutoff
- The small-scale structure of magnetohydrodynamic turbulence with large magnetic Prandtl numbers
- Turbulent dynamo in a conducting fluid and partially ionized gas
- Reconnection Studies Under Different Types of Turbulence Driving
- Ordinary and Viscosity-Damped MHD Turbulence
- Damping of MHD turbulence in partially ionized plasma: implications for cosmic ray propagation
- Sub-Alfvenic Non-Ideal MHD Turbulence Simulations with Ambipolar Diffusion: I. Turbulence Statistics
- The Inability of Ambipolar Diffusion to set a Characteristic Mass Scale in Molecular Clouds
- Effect of Fractional Kinetic Helicity on Turbulent Magnetic Dynamo Spectra
- Can the turbulent galactic dynamo generate large-scale magnetic fields?
- Alfvenic Turbulence Beyond the Ambipolar Diffusion Scale
- Magnetic field amplification in supernova remnants
- Linewidth Differences of Neutrals and Ions Induced by MHD Turbulence
- Direct Evidence for Two-Fluid Effects in Molecular Clouds
- A Two-Fluid Method for Ambipolar Diffusion
- Driven Multifluid MHD Molecular Cloud Turbulence
- Observational Diagnostics for Two-Fluid Turbulence in Molecular Clouds As Suggested by Simulations
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