Abstract Details
Abstracts
Author: Alexander G Haywood
Requested Type: Poster
Submitted: 2025-03-14 16:11:52
Co-authors: F. Ebrahimi
Contact Info:
Princeton University
2961 Frist Campus Center
Princeton, New Jersey 08544
USA
Abstract Text:
Instability-driven turbulence is key to understanding accretion and angular momentum transport in astrophysical disks. This work investigates MHD stability dynamics in differentially rotating systems, focusing on the weak-field Magneto-Rotational Instability (MRI) as well as the strong-field limit global non-axisymmetric Magneto-Curvature Instability (MCI) (Ebrahimi & Pharr ApJ 936, 2022). We analyze how aspect ratio, Lundquist number, and flow/field configurations affect these instabilities, employing a novel spectral approximation (Zou et al. PrE 101, 2020). We benchmark results from our spectral approximation against linear NIMROD MHD simulations in an unstratified Keplerian cylinder across various Lundquist numbers and aspect ratios. To study free energy contributions from vorticity, vorticity gradients, and non-ideal effects, we apply an extended effective potential formalism (Ebrahimi & Haywood PoP Letter 32, 3, 2025). Our results show that MCI dominates in thick, low-aspect-ratio disks with low vorticity and strong vorticity gradients, whereas MRI dominates in thin, high-aspect-ratio disks with high vorticity and weaker gradients. More broadly, we identify the most global MCI mode as the primary onset mechanism and provide a method for estimating instability conditions based on system parameters. This work is supported by NSF.
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