{
  "id": "1706.06607",
  "version": "v1",
  "published": "2017-06-20T18:00:57.000Z",
  "updated": "2017-06-20T18:00:57.000Z",
  "title": "Filament formation in wind-cloud interactions. II. Clouds with turbulent density, velocity, and magnetic fields",
  "authors": [
    "Wladimir Banda-Barragán",
    "Christoph Federrath",
    "Roland Crocker",
    "Geoffrey Bicknell"
  ],
  "comment": "25 pages plus appendices, 21 figures. Submitted to MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present a set of numerical experiments designed to systematically investigate how turbulence and magnetic fields influence the morphology, energetics, and dynamics of filaments produced in wind-cloud interactions. We cover 3D magnetohydrodynamic systems of supersonic winds impacting clouds with turbulent density, velocity, and magnetic fields. We find that log-normal density distributions aid shock propagation through clouds, increasing their velocity dispersion and producing filaments with expanded cross sections and highly-magnetised knots and sub-filaments. In self-consistently turbulent scenarios the ratio of filament to initial cloud magnetic energy densities is ~1. The effect of Gaussian velocity fields is bound to the turbulence Mach number: Supersonic velocities trigger a rapid cloud expansion; subsonic velocities only have a minor impact. The role of turbulent magnetic fields depends on their tension and is similar to the effect of radiative losses: the stronger the magnetic field or the softer the gas equation of state, the greater the magnetic shielding at wind-filament interfaces and the suppression of Kelvin-Helmholtz instabilities. Overall, we show that including turbulence and magnetic fields is crucial to understanding cold gas entrainment in multi-phase winds. While cloud porosity and supersonic turbulence enhance the acceleration of clouds, magnetic shielding protects them from ablation and causes Rayleigh-Taylor-driven sub-filamentation. Wind-swept clouds in turbulent models reach distances ~15-20 times their core radius and acquire bulk speeds ~0.3-0.4 of the wind speed in one cloud-crushing time, which are three times larger than in non-turbulent models. In all simulations the ratio of turbulent magnetic to kinetic energy densities asymptotes at ~0.1-0.4, and convergence of all relevant dynamical properties requires at least 64 cells per cloud radius.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-06-20T18:00:57.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "magnetic field",
      "wind-cloud interactions",
      "turbulent density",
      "filament formation",
      "initial cloud magnetic energy densities"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 25,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}