# Non-ideal MHD simulation of HL Tau disk: formation of rings

## TL;DR

This study uses 3D non-ideal MHD simulations to explore how snow lines and magnetic effects can produce rings and gaps in the HL Tau disk, aligning with recent high-resolution observations.

## Contribution

It introduces a comprehensive model combining dust evolution, non-ideal MHD effects, and snow line physics to explain ring formation in protoplanetary disks.

## Key findings

- Gaps and rings form rapidly from varying accretion rates across snow lines.
- Ambipolar diffusion causes preferential midplane accretion and magnetic reconnection.
- Magnetic effects and snow lines together can produce observable disk structures.

## Abstract

Recent high resolution observations unveil ring structures in circumstellar disks. The origin of these rings has been widely investigated under various theoretical scenarios. In this work we perform global 3D non-ideal MHD simulations including effects from both Ohmic resistivity and ambipolar diffusion (AD) to model the HL Tau disk. The non-ideal MHD diffusion profiles are calculated based on the global dust evolution calculation including sintering effects. Disk ionization structure changes dramatically across the snow line due to the change of dust size distribution close to snow line of major volatiles. We find that accretion is mainly driven by disk wind. Gaps and rings can be quickly produced from different accretion rates across snow line. Furthermore, ambipolar diffusion (AD) leads to highly preferential accretion at midplane, followed by magnetic reconnection. This results a local zone of decretion that drains of mass in the field reconnection area, which leaves a gap and an adjacent ring just outside it. Overall, under the favorable condition, both snow lines and non-ideal MHD effects can lead to gaseous gaps and rings in protoplanetary disks.