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Updated: May 8, 2026
06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Magnetohydrodynamic stability of stochastically driven accretion flows
Sujit Kumar Nath1, Banibrata Mukhopadhyay, Amit K Chattopadhyay
1Department of Physics, Indian Institute of Science, Bangalore 560 012, India. sujitkumar@physics.iisc.ernet.in
Summary
Stochastic noise in rotating shear flows can generate instability in astrophysical accretion disks. This study reveals that noise-induced correlations are independent of stable background profiles, suggesting universal behavior in hydromagnetic perturbations.
Area of Science:
- Astrophysics and Plasma Physics
- Fluid Dynamics and Magnetohydrodynamics
Background:
- Astrophysical accretion disks require turbulence for observed phenomena, yet linear theory predicts stability for certain flows.
- Magnetorotational instability (MRI) in weak magnetic fields partially resolves this mismatch but requires further investigation.
- The role of stochastic noise in driving turbulence and instability in these systems remains underexplored.
Purpose of the Study:
- To investigate the impact of stochastic noise on magnetohydrodynamic (MHD) perturbations in rotating shear flows.
- To resolve the mismatch between linear theory and observations in astrophysical contexts, particularly for hot flows.
- To understand the generation of instability in flows mimicking accretion disks around compact objects.
Main Methods:
- Focus on a simplified model: a plane shear flow with Coriolis effects, representing a segment of an accretion disk.
- Analysis of three-dimensional hydromagnetic perturbations in the presence of stochastic noise.
- Examination of temporal and spatial autocorrelations and cross-correlations of perturbations.
Main Results:
- Stochastically driven flows exhibit significant temporal and spatial autocorrelations and cross-correlations.
- These correlations lead to substantial energy dissipation and generate instability.
- Autocorrelations and cross-correlations are independent of the background angular velocity profiles, indicating universality.
Conclusions:
- Stochastic noise can be a key mechanism for generating turbulence and instability in otherwise stable rotating shear flows.
- The observed universality of correlations suggests broad applicability to various astrophysical scenarios.
- This work provides a foundational understanding of 3D hydromagnetic perturbations in noisy, rotating shear flows.
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