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Anders Johansen. Profile picture.

Anders Johansen

Professor

Anders Johansen. Profile picture.

High-resolution simulations of planetesimal formation in turbulent protoplanetary discs

Author

  • Anders Johansen
  • H. Klahr
  • Th. Henning

Summary, in English

We present high-resolution computer simulations of dust dynamics and planetesimal formation in turbulence generated by the magnetorotational instability. We show that the turbulent viscosity associated with magnetorotational turbulence in a non-stratified shearing box increases when going from 256(3) to 512(3) grid points in the presence of a weak imposed magnetic field, yielding a turbulent viscosity of alpha approximate to 0.003 at high resolution. Particles representing approximately meter-sized boulders concentrate in large-scale high-pressure regions in the simulation box. The appearance of zonal flows and particle concentration in pressure bumps is relatively similar at moderate (256(3)) and high (512(3)) resolution. In the moderate-resolution simulation we activate particle self-gravity at a time when there is little particle concentration, in contrast with previous simulations where particle self-gravity was activated during a concentration event. We observe that bound clumps form over the next ten orbits, with initial birth masses of a few times the dwarf planet Ceres. At high resolution we activate self-gravity during a particle concentration event, leading to a burst of planetesimal formation, with clump masses ranging from a significant fraction of to several times the mass of Ceres. We present a new domain decomposition algorithm for particle-mesh schemes. Particles are spread evenly among the processors and the local gas velocity field and assigned drag forces are exchanged between a domain-decomposed mesh and discrete blocks of particles. We obtain good load balancing on up to 4096 cores even in simulations where particles sediment to the mid-plane and concentrate in pressure bumps.

Department/s

  • Lund Observatory

Publishing year

2011

Language

English

Publication/Series

Astronomy & Astrophysics

Volume

529

Document type

Journal article

Publisher

EDP Sciences

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • (MHD)
  • magnetohydrodynamics
  • accretion disks
  • accretion
  • methods: numerical
  • planets and satellites: formation
  • planetary systems
  • turbulence

Status

Published

ISBN/ISSN/Other

  • ISSN: 0004-6361