On the convergence of Magnetorotational turbulence in stratified isothermal shearing boxes

TL;DR

This study investigates the convergence behavior of magnetorotational turbulence in stratified isothermal shearing boxes, revealing persistent decrease in Maxwell stresses at high resolutions and suggesting complex dynamo mechanisms as a possible cause.

Contribution

It provides the highest resolution simulations to date, demonstrating the lack of convergence and proposing explanations involving multi-layer dynamo systems.

Findings

Maxwell stresses decrease with increasing resolution

No clear evidence of convergence even at 200 grid points per pressure scale height

Possible multi-layer dynamo systems influence turbulence behavior

Abstract

We consider the problem of convergence in stratified isothermal shearing boxes with zero net magnetic flux. We present results with the highest resolution to-date--up to 200 grid-point per pressure scale height--that show no clear evidence of convergence. Rather, the Maxwell stresses continue to decrease with increasing resolution. We propose some possible scenarios to explain the lack of convergence based on multi-layer dynamo systems.