Radiative Nonideal MHD Simulations of Inner Protoplanetary Disks: Temperature Structures, Asymmetric Winds, and Episodic Surface Accretion

TL;DR

This study uses advanced 2D MHD simulations with radiation transfer to explore the complex temperature structures, asymmetric winds, and episodic accretion phenomena in the inner regions of protoplanetary disks, revealing the impact of magnetic field alignment.

Contribution

It introduces a comprehensive simulation framework that combines nonideal MHD effects with radiative transfer, providing new insights into disk dynamics and thermal structures influenced by magnetic field orientation.

Findings

Fast one-sided surface accretion and asymmetric winds with aligned magnetic fields.

Clump formation and accretion driven by radiative feedback.

Wind effects dominate the thermal regulation of the disk, not accretion heating.

Abstract

We perform two-dimensional global magnetohydrodynamic (MHD) simulations including the full nonideal MHD effects (Ohmic diffusion, Hall effect, and ambipolar diffusion) and approximate radiation transport to understand the dynamics and thermal structure of the inner protoplanetary disks (PPDs). We have developed a simple radiative transfer model for PPDs that reasonably treats stellar non-thermal (XUV), stellar thermal (optical/infrared), and re-emitted radiations, reproducing the temperature structures from Monte Carlo radiative transfer. Our simulations show fast one-sided surface accretion ($\sim 10\%$ of Keplerian velocity) and asymmetric disk winds when the vertical magnetic field is aligned with the disk angular momentum. The asymmetry is due to the failure of the wind on the side with the accretion layer. On the accreting surface, clumps are repeatedly generated and accrete, driven by radiative feedback. For the anti-aligned fields, surface accretion becomes more moderate and time-variable, while the winds remain largely symmetric. For the thermal structure, accretion heating does not affect the disk temperature in any of our runs. This is because (1) the accretion energy dissipates via Joule heating at 2--3 gas scale heights, where low optical depth enables efficient radiative cooling, and (2) the winds remove $\gtrsim 10\%$ of the accretion energy. In contrast, the winds enhance radiative heating by elevating the irradiation front. These results highlight the importance of coupling between gas dynamics and radiation transport in PPDs, and provide observable magnetic activities such as fast episodic accretion, wind asymmetry, and molecular survival in XUV-irradiated winds.