Non-resonant grain acceleration in MHD turbulence |
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| Authors: | Huirong Yan |
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| Institution: | Department of Planetary Sciences &Steward Observatory, University of Arizona, 1629 E University Blvd, Tucson, AZ 85721, USA |
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| Abstract: | We discuss a new type of dust acceleration mechanism that acts in a turbulent magnetized medium. The magnetohydrodynamic turbulence can accelerate grains through resonant as well as non-resonant interactions. We show that the magnetic compression provides higher velocities for super-Alfvénic 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 submicron 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. |
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| Keywords: | acceleration of particles dust extinction ISM: kinematics and dynamics ISM: magnetic fields |
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