Fluctuation dynamo amplified by intermittent shear bursts in convectively driven magnetohydrodynamic turbulence

Abstract

Intermittent large-scale high-shear flows are found to occur frequently and spontaneously in direct numerical simulations of statistically stationary turbulent Boussinesq magnetohydrodynamic (MHD) convection. The energetic steady-state of the system is sustained by convective driving of the velocity field and small-scale dynamo action. The intermittent emergence of flow structures with strong velocity and magnetic shearing generates magnetic energy at an elevated rate over time-scales longer than the characteristic time of the large-scale convective motion. The resilience of magnetic energy amplification suggests that intermittent shear-bursts are a significant driver of dynamo action in turbulent magnetoconvection.

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Cited by in corpus (4)

• Realistic modeling of local dynamo processes on the Sun
• Enhancement of small-scale turbulent dynamo by large-scale shear
• Extreme-value statistics from Lagrangian convex hull analysis for homogeneous turbulent Boussinesq convection and MHD convection
• High dimensional tori and chaotic and intermittent transients in magnetohydrodynamic Couette flows