Recent observations of protoplanetary discs have unveiled their wealth of substructure, the origins and
implications of which are yet to be fully understood. Of particular interest is whether they promote
planet formation, whether they indicate that planet formation is already underway, and what role they
play in setting the architecture of planetary systems. In this thesis I present my investigations into
physical processes that can give rise to large-scale, non-axisymmetric substructure.
I discuss our current understanding of substructure in protoplanetary discs, and provide an overview of
the key processes involved in planet formation. I present the theoretical basis for vortex generation by an
accreting planetary embryo. Through hydrodynamics simulations, I show that in massive, axisymmetric
dust traps, the growth of a planetary core via pebble accretion produces strong thermal feedback on the
disc, making it unstable to vortex formation. I demonstrate how this can further enhance the accretion
rate onto the planetary core as well as produce observable non-axisymmetric substructure. I investigate
how this process varies with the mass of dust in the ring as well as the local background gas temperature,
and show that the thermal feedback always acts to increase the planet’s mass. I establish that the required
dust masses lie towards the extreme end of those inferred from observations, otherwise the background
temperature must be sufficiently low to emphasize the thermal feedback from the embryo’s accretion
luminosity.
I also investigate how warped and twisted regions of protoplanetary discs cast shadows across the
disc, and how this manifests in observations, giving the appearance of non-axisymmetric substructure.
I show that this can be used to constrain the geometry of discs in which there is evidence for strong
misalignments between their inner and outer regions.