Sebastien FROMANG : DAMTP, Universtity of Cambridge
Dust settling in turbulent protoplanetary discs
In laminar protoplanetary discs, dust particles are known to quickly settle toward the equatorial plane. This is the first step toward planet formation. However, this simple picture is likely to be modified by MHD turbulence. In this talk, I will present local numerical MHD simulations of stratified and turbulent dics. Dust particles of various sizes are released in the disc and evolve under the influence of the turbulence. Small particles are shown to spread diffusively, while some significant settling is observed for larger particles (1 to 10 centimeters). These results are interpreted with a simple model in which the turbulent diffusion coefficient is expressed in terms of the statistical properties of the flow. The agreement between the simulations and the model is very good.Last modified: Sun Jul 9 17:35:43 2006