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High-resolution simulations of planetesimal formation in turbulent protoplanetary discs

Johansen, Anders LU ; Klahr, H. and Henning, Th. (2011) In Astronomy & Astrophysics 529.
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
(MHD), magnetohydrodynamics, accretion disks, accretion, methods: numerical, planets and satellites: formation, planetary systems, turbulence
in
Astronomy & Astrophysics
volume
529
publisher
EDP Sciences
external identifiers
  • wos:000289557200070
  • scopus:79953299905
ISSN
0004-6361
DOI
10.1051/0004-6361/201015979
language
English
LU publication?
yes
id
152069d4-9cc6-460d-b912-8fb685ae3dcf (old id 1966026)
date added to LUP
2011-05-20 12:11:12
date last changed
2017-10-01 04:06:34
@article{152069d4-9cc6-460d-b912-8fb685ae3dcf,
  abstract     = {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.},
  author       = {Johansen, Anders and Klahr, H. and Henning, Th.},
  issn         = {0004-6361},
  keyword      = {(MHD),magnetohydrodynamics,accretion disks,accretion,methods: numerical,planets and satellites: formation,planetary systems,turbulence},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {High-resolution simulations of planetesimal formation in turbulent protoplanetary discs},
  url          = {http://dx.doi.org/10.1051/0004-6361/201015979},
  volume       = {529},
  year         = {2011},
}