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Advancement: Robustness of an essentially nonlinear dynamo mechanism

Speaker Name: 
Jacob B. Noone Wade
Speaker Title: 
PhD Student (Advisor: Nic Brummell)
Speaker Organization: 
Applied Mathematics
Start Time: 
Thursday, March 14, 2019 - 12:00pm
End Time: 
Thursday, March 14, 2019 - 2:00pm
Engineering 2, Room 475
Nic Brummell

Abstract:  Through direct numerical simulations, we study the influence of turbulence on a novel essentially nonlinear dynamo (END) mechanism. This dynamo operates through the interaction of a velocity shear with magnetic buoyancy mitigated by secondary Kelvin-Helmholtz instabilities. As opposed to the traditional mean-field or kinematic theory treatment, this END paradigm only exhibits dynamo action if the initial magnetic configuration is finite and above a critical threshold. We first study the effects of the smallest scales of turbulence by injecting noise into the magnetic fields. We then seek to study the effect of a wider range of scales by analyzing the effects of actual resolved convection. To achieve a setup that is perhaps more realistic, we ultimately embed the END mechanism in a two-layer penetrative simulation. These preliminary results indicate that turbulence in many forms does little to hinder the END mechanism.