Conveners
Tuesday Morning
- Richard Nelson (Queen Mary University of London)
Prof.
Mark Wardle
(Macquarie University)
05/08/2014, 09:00
Workshop Main Programme
Flux-freezing breaks down under the low levels of ionisation in molecular cloud cores and protoplanetary discs. The dominant processes are ambipolar diffusion and hall drift, which enable slippage of magnetic flux through the predominantly neutral gas. The nature of the field line drift through the bulk neutral component of the gas is as important as its magnitude. Under ambipolar diffusion,...
Donna Rodgers Lee
(Dublin Institute for Advanced Studies)
05/08/2014, 09:30
Workshop Main Programme
The mechanisms which drive circumstellar disk evolution are still poorly understood. In this context the MRI is likely to play an important role in the evolution of protoplanetary disks. I will discuss the results of O'Keeffe & Downes (2014) who perform global multifluid simulations of protoplanetary disks which study the magnetorotational instability (MRI). The inclusion of non-ideal effects...
Dr
Matthew Kunz
(Princeton University)
05/08/2014, 10:00
Workshop Main Programme
The magnetorotational instability (MRI) is the most promising mechanism by which angular momentum is efficiently transported outwards in astrophysical disks. However, its application to protoplanetary disks remains problematic. These disks are so poorly ionized that they may not support magnetorotational turbulence in regions referred to as "dead zones". While purported dead zones have...
Dr
Geoffroy Lesur
(CNRS/IPAG)
05/08/2014, 11:00
Workshop Main Programme
The existence of magnetically driven turbulence in protoplanetary discs has been a central question since the discovery of the magnetorotational instability (MRI). Early models considered Ohmic diffusion only and led to a scenario of layered accretion, in which a magnetically ``dead'' zone in the disc midplane is embedded within magnetically ``active'' surface layers at distances of about...
Dr
Xuening Bai
(Harvard-Smithsonian Center for Astrophysics)
05/08/2014, 11:30
Workshop Main Programme
I will present recent local stratified shearing-box simulations on the gas dynamics of protoplanetary disks (PPDs) that self-consistently take into account all three non-ideal MHD effects. I argue that PPDs are most likely threaded by external poloidal magnetic flux, and will address 1). launching of magnetocentrifugal wind in the inner disk, 2). dependence of the gas dynamics on the external...
