| Abstract: |
Angular momentum transport processes of gas play an important role in determining the evolution and structure of protoplanetary disks. In the innermost part of the disk, the ionization is sufficiently high that the magnetic rotational instability (MRI)-driven turbulence acts as an effective viscosity to transport angular momentum outward. On the other hand, toward the outside of the disk, the ionization decreases, creating a region where MRI is suppressed (dead zone). In the dead zone, the torque of the coherent global magnetic field transports the angular momentum outward. Different angular momentum transport mechanisms operate in different regions of protoplanetary disks.
Previous studies using numerical simulations have investigated the active and dead zones separately.
However, it is essential to consider both active and dead zones simultaneously to clarify the global mass and angular momentum transport processes, mass loss processes, and magnetic flux transport processes that determine the disk evolution. We therefore performed global non-ideal magnetohydrodynamic simulations with realistic Ohmic resistivity and ambipolar diffusion using Fugaku supercomputer. The simulation has a wide dynamic range (0.1 au < r < 10 au) that includes the active and dead zones in the computational domain, with an appropriate resolution to capture the MRI turbulence in the active zone. In the seminar, I will present on the transition zone formed between the active and dead zones that we have discovered and its impact on the angular momentum and magnetic flux transport processes, as well as its implications for planet formation.
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