Nonresonant Grain Acceleration in MHD Turbulence
arXiv:0903.3062 · doi:10.1111/j.1365-2966.2009.15070.x
Abstract
We discuss a new type of dust acceleration mechanism that acts in a turbulent magnetized medium. The magnetohydrodynamic (MHD) turbulence can accelerate grains through resonant as well as nonresonant interactions. We show that the magnetic compression provides higher velocities for super-Alfvenic turbulence and can accelerate an extended range of grains in warm media compared to gyroresonance. While fast modes dominate the acceleration for the large grains, slow modes can be important for sub-micron grains. We provide comprehensive discussion of all the possible grain acceleration mechanisms in interstellar medium. We show that supersonic velocities are attainable for Galactic dust grains. We discuss the consequence of the acceleration. The implications for extinction curve, grain alignment, chemical abundance, etc, are provided.
8 pages, 2 figures, accepted to MNRAS, minor changes
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- Velocity Field of Compressible MHD Turbulence: Wavelet Decomposition and Mode Scalings
- A unified model of grain alignment: radiative alignment of interstellar grains with magnetic inclusions
- Superdiffusion of Cosmic Rays: Implications for Cosmic Ray Acceleration
- What are little worlds made of? Stellar abundances and the building blocks of planets
- Paramagnetic alignment of small grains: a novel method for measuring interstellar magnetic fields
- Revisiting Acceleration of Charged Grains in Magnetohydrodynamic Turbulence
- Cosmic Ray transport through gyroresonance instability in compressible turbulence
- Do Androids Dream of Magnetic Fields? Using Neural Networks to Interpret the Turbulent Interstellar Medium
- Acceleration of small astrophysical grains due to charge fluctuations
- Dust dynamics in RAMSES -- I. Methods and turbulent acceleration
- Acceleration of Small Dust Grains due to Charge Fluctuations
- Effects of turbulent dust grain motion to interstellar chemistry
- Dust dynamics in RAMSES -- II. Equilibrium drift velocity distributions of charged dust grains