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Non-linear evolution of instabilities between dust and sound waves

Moseley, Eric R. and Squire, Jonathan and Hopkins, Philip F. (2019) Non-linear evolution of instabilities between dust and sound waves. Monthly Notices of the Royal Astronomical Society, 489 (1). pp. 325-338. ISSN 0035-8711.

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We study the non-linear evolution of the acoustic ‘resonant drag instability’ (RDI) using numerical simulations. The acoustic RDI is excited in a dust–gas mixture when dust grains stream through gas, interacting with sound waves to cause a linear instability. We study this process in a periodic box by accelerating neutral dust with an external driving force. The instability grows as predicted by linear theory, eventually breaking into turbulence and saturating. As in linear theory, the non-linear behaviour is characterized by three regimes – high, intermediate, and low wavenumbers – the boundary between which is determined by the dust–gas coupling strength and the dust-to-gas mass ratio. The high and intermediate wavenumber regimes behave similarly to one another, with large dust-to-gas ratio fluctuations while the gas remains largely incompressible. The saturated state is highly anisotropic: dust is concentrated in filaments, jets, or plumes along the direction of acceleration, with turbulent vortex-like structures rapidly forming and dissipating in the perpendicular directions. The low-wavenumber regime exhibits large fluctuations in gas and dust density, but the dust and gas remain more strongly coupled in coherent ‘fronts’ perpendicular to the acceleration. These behaviours are qualitatively different from those of dust ‘passively’ driven by external hydrodynamic turbulence, with no back-reaction force from dust on to gas. The virulent nature of these instabilities has interesting implications for dust-driven winds in a variety of astrophysical systems, including around cool stars, in dusty torii around active-galactic-nuclei, and in and around giant molecular clouds.

Item Type:Article
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URLURL TypeDescription
Squire, Jonathan0000-0001-8479-962X
Hopkins, Philip F.0000-0003-3729-1684
Additional Information:© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2019 July 25. Received 2019 July 25; in original form 2018 October 17. Published: 12 August 2019. We would like to thank Stefania Moroianu for a number of helpful discussions. Support for PFH, JS, and ERM was provided by an Alfred P. Sloan Research Fellowship, National Science Foundation Collaborative Research Grant #1715847 and CAREER grant #1455342, and National Aeronautics and Space Administration grants NNX15AT06G, JPL 1589742, 17-ATP17-0214. JS was also supported by the Royal Society Te Apārangi through contracts RDF-U001804 and UOO1727. Numerical calculations were run on the Caltech compute cluster ‘Wheeler,’ allocations from the Extreme Science and Engineering Discovery Environment TG-AST130039 and PRAC NSF.1713353 supported by the National Science Foundation, and National Aeronautics and Space Administration HEC SMD-16-7592.
Group:TAPIR, Walter Burke Institute for Theoretical Physics, Astronomy Department
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Royal Society Te ApārangiRDF-U001804
Royal Society Te ApārangiRDF-UOO1727
Subject Keywords:instabilities – turbulence – planets and satellites: formation – ISM: kinematics and dynamics – galaxies: formation
Issue or Number:1
Record Number:CaltechAUTHORS:20191025-092112560
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Official Citation:Eric R Moseley, Jonathan Squire, Philip F Hopkins, Non-linear evolution of instabilities between dust and sound waves, Monthly Notices of the Royal Astronomical Society, Volume 489, Issue 1, October 2019, Pages 325–338,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99445
Deposited By: Tony Diaz
Deposited On:25 Oct 2019 16:31
Last Modified:25 Oct 2019 16:31

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