PF-03-0006

The Hall Effect and Photoevaporative Outflows on Protoplanetary Disks

Eleftheria Sarafidou, Oliver Gressel, Giovanni Picogna, Barbara Ercolano

Understanding the evolution of the planet forming inner regions of circumstellar disks is one of the most prominent astrophysical problems. There are two fundamental drivers of disk evolution, which will ultimately lead to the dispersal of the disk on timescales comparable to the observational constraints. The first is photoevaporation (see, e.g., Alexander et al. 2013; Ercolano and Pascucci 2017) i.e., the dispersal of protoplanetary disks (PPDs) via winds driven by thermochemical heating through X-rays, extreme/far-ultraviolet radiation (EUV/FUV) driven winds that are primarily associated with mass loss. The second driver is accretion of the disk material onto the central star through the redistribution of angular momentum (see, e.g.,Königl and Salmeron 2010; Turner et al. 2014; Frank et al. 2014). Additionally, when considering the detailed ionization structure in the inner regions of PPDs, it is clear that the three non ideal magnetohydrodynamic (MHD) effects have also to be taken into account. Large stretches of the disk are expected to remain laminar due to the combined dissipative effect of ambipolar diffusion and ohmic resistivity (Bai and Stone 2013; Bai 2013), whereas in regions where the Hall effect is dominant, the Hall-shear instability can nevertheless amplify large-scale horizontal magnetic field and provide a means for non-turbulent accretion. We are producing computer models of the inner regions of PPDs, by extending the non-ideal MHD model of Gressel et al. (2020), taking into account radiative, thermodynamic and non-ideal magnetohydrodynamic aspects simultaneously. We perform global axisymmetric MHD simulations of combined photoevaporative (including X-ray and FUV) and magnetocentrifugal disk outflows, including a self-consistent temperature and ionization structure parametrization (Picogna et al. 2019). The mass outflow and accretion rates of our models are examined, as well as the evolution of the poloidal magnetic field lines threading the disk.