Observations of outflows and angular momentum transport from the inner to the outer disk

Viscous disks have been at the base of our current understanding of angular momentum transport and disk accretion. However, new theoretical studies predict that turbulence might not be efficient enough to carry angular momentum in the inner layers of circumstellar disks within 0.5 to 10 au from the source. Instead, strong MHD disk winds are thought to be launched in this central region, carrying away the excess angular momentum in a very efficient way. Recently, IR interferometers have begun to resolve the inner disk regions of protoplanetary disks. These studies surprisingly reveal the presence of wind emission in the innermost regions of disks, within a few stellar radii from the source, and thus indicate that MHD winds might play a major role in the removal of angular momentum. A new generation of much powerful interferometric instruments, more sensitive and with improved imaging capabilities is now coming on stream. In this talk, I will review the latest findings in the field of high angular resolution observations of protoplanetary disks, and how these studies can help us to constrain the inner disk structure and evolution.