Momentum transport in simulations of differentially rotating disks with global curvature effects A. Haywood, F. Ebrahimi, M. Pharr

Instability-driven turbulence has a crucial role in explaining the accretion process and angular momentum transport in astrophysical disks. Here, we examine the nonlinear transport properties of Magneto-Rotational Instability (MRI) in the weak-field limit in a differentially rotating system, as well as the newly-discovered global non-axisymmetric Magneto-Curvature Instability (MCI) in the strong-field limit (Ebrahimi & Pharr ApJ 936, 2022). In an unstratified Keplerian cylinder, we perform fully nonlinear 2D and 3D MHD simulations at various Lunquist numbers and aspect ratios, and study the nonlinear state and generated momentum transport by calculating fluid and Maxwell stresses from both MRI and MCI. Unlike MRI, which is typically concentrated in flow shear regions, MCIs are global distinct low-frequency non-axisymmetric modes driven unstable by global differential rotation and spatial curvature. We present simulations at various aspect ratios and Lundquist numbers. The effect of transient reconnecting tearing modes on momentum transport in these nonlinear simulations will also be investigated. This work is supported by NSF.