Philip Armitage

Turbulence and magnetized disk winds are agents that can remove angular momentum and facilitate inflow through accretion disks. Initially considered as largely alternate hypotheses for why disks accrete, current theoretical work suggests that they are linked through the net flux – vertical magnetic field that threads the entire disk. Multiple numerical simulations, and more recently observations of different disk systems, support the key role of net magnetic flux in disk evolution. I will discuss ongoing work, focused on protoplanetary disks, that uses disk demographics to constrain the relative importance of winds and turbulence in these disks. I will conclude by discussing what I see as important, but currently intractable, theoretical problems in this field.