Acceleration of Very Small Dust Grains Due to Random Charge Fluctuations

Type Journal Article
Names Thiem Hoang, A. Lazarian
Publication The Astrophysical Journal
Volume 761
Pages 96
Journal Abbreviation The Astrophysical Journal
Date December 1, 2012
DOI 10.1088/0004-637X/761/2/96;
ISSN 0004-637X
URL http://adsabs.harvard.edu/abs/2012ApJ...761...96H
Library Catalog NASA ADS
Abstract We study the acceleration of very small dust grains including polycyclic aromatic hydrocarbons arising from electrostatic interactions of dust grains that have charge fluctuating randomly in time. Random charge fluctuations of very small grains due to discrete charging events (i.e., sticking collisions with electrons and ions in plasma, and emission of photoelectrons by UV photons) are simulated using the Monte Carlo (MC) method. The motion of dust grains in randomly fluctuating electric fields induced by surrounding charged grains is studied using MC simulations. We identify the acceleration induced by random charge fluctuations as a dominant acceleration mechanism for very small grains in the diffuse interstellar medium (ISM). We find that this acceleration mechanism is efficient for environments with a low degree of ionization (i.e., large Debye length), where charge fluctuations are slow but have a large amplitude. The implications of the present acceleration mechanism for grain coagulation and shattering in the diffuse ISM and dark clouds are also discussed.
Tags Acceleration of Particles, DUST, ISM: kinematics and dynamics, extinction
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