PI: Henrik Latter

The turbulent flows within protoplanetary discs regulate not only accretion on to nascent stars but also the assembly of solids and gas into planets. They hence are central to any study of our origins and of the possibility of life outside the Solar System. They are also highly complex and dynamic magnetohydrodynamic (MHD) flows, containing a hot turbulent inner region close to the star and a cooler laminar region further away. The work carried out under DiRAC grant dp316, building on previous awards, investigates the flows of both dust and gas in this region, in particular, (a) how structures such as vortices, wavetrains, and turbulent fronts collect and loft larger dust and (b) how magnetic outflows, launched from the disc, entrain small solid particles, redistributing them to other radii, while simultaneously thermally re-processing them.

Of the notable results discovered so far is the life cycle of vortices formed at the edge of the turbulent region and their efficiency in collecting dust, and then scattering it as instabilities assail the structure. Another is the action of corrugation waves, launched by the vortex, which both collect and distort the dust disk. These two processes can be observed in the figure below, where only the dust density it plotted.

Figure: A composite image using snapshot of a simulation of the dust in a protoplanetary disk, showing the midplane dust density and, via a cut, its vertical lofting. One can discern on the edge of the inner turbulent disc, an elongated vortex, while at larger radii, propagating corrugation waves both collect and loft the dust in near axisymmetric fronts.