Concentrating Dust in Protoplanetary Disks Through Turbulent Thermal Diffusion

Turbulent thermal diffusion: a way to concentrate dust in protoplanetary discs

Author:

Hubbard

Abstract:

Turbulence acting on mixes of gas and particles generally diffuses the latter evenly through the former. However, in the presence of background gas temperature gradients, a phenomenon known as turbulent thermal diffusion appears as a particle drift velocity (rather than a diffusive term). This process moves particles from hot regions to cold ones. We re-derive turbulent thermal diffusion using astrophysical language and demonstrate that it could play a major role in protoplanetary discs by concentrating particles by factors of tens. Such a concentration would set the stage for collective behaviour such as the streaming instability and hence planetesimal formation.