Dust dynamics in RAMSES – I. Methods and turbulent acceleration

Eric R. Moseley, R. Teyssier, B. T. Draine

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Supernova ejecta and stellar winds are believed to produce interstellar dust grains with relatively large sizes. Smaller grains can be produced via the shattering of large grains that have been stochastically accelerated. To understand this stochastic acceleration, we have implemented novel magnetohydrodynamic (MHD) particle-in-cell methods into the astrophysical fluid code RAMSES. We treat dust grains as a set of massive ‘superparticles’ that experience aerodynamic drag and Lorentz force. We subject our code to a range of numerical tests designed to validate our method in different physical conditions, as well as to illustrate possible mechanisms by which grains can be accelerated. As a final test as well as a foundation for future work, we present the results of decaying dusty MHD turbulence simulations with grain parameters chosen to resemble 1–2 μm grains in typical cold neutral medium conditions. We find that in these conditions, these grains can be effectively accelerated to well beyond their shattering velocities. This is true for both electrically charged and neutral grains. While the peak of the gas-grain relative drift velocity distribution is higher for neutral grains, the drift velocity distribution of charged grains exhibits an extended exponential tail out to much greater velocities. Even so, the shapes of the distributions are such that the extra gas-grain coupling provided by the Lorentz force offers grains relative protection from shattering. We also discuss the connection between our simulations and the relatively pristine ∼μm-sized pre-solar grains that do not appear to have undergone significant wear in their lifetimes.

Original languageEnglish (US)
Pages (from-to)2825-2844
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume518
Issue number2
DOIs
StatePublished - Jan 1 2023

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • ISM: kinematics and dynamics
  • MHD
  • dust, extinction
  • galaxies: ISM
  • methods: numerical
  • turbulence

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