The inner regions of protoplanetary disks, where the majority of
currently detected exoplanets and the terrestrial planets of our Solar
System are located, are prone to various forms of instability. In
particular, the transition between the innermost highly turbulent region
and the low-turbulence "dead zone" poses significant challenges for
long-term dynamic modelling. I will present radiation-hydrodynamic
simulations that show large-scale variability on hundred- to
thousand-year timescales, in the form of episodic accretion outbursts,
as an intrinsic consequence of the inner disk architecture. These
periodic events significantly reshape the density, pressure and
temperature structure, potentially having impactful consequences for the
formation and migration of planets in the inner disk regions. I will
also elaborate on the sensitivity of the instability mechanism and burst
morphologies on opacities and large-scale magnetic fields.
Despite the significant computational challenges and the physical
complexity of the inner disk regions, our models strongly imply that the
innermost few AU of a protoplanetary disk are not dynamically stable
over long timescales, which should be taken into account when
investigating the formation and migration of planets close to their host
star.