Pallavi Bhat

A unified large/small-scale dynamo in helical turbulence

We use high resolution direct numerical simulations (DNS) to show that helical turbulence can generate significant large-scale fields even in the presence of strong small-scale dynamo action. Durin ...

FLUCTUATION DYNAMO AT FINITE CORRELATION TIMES AND THE KAZANTSEV SPECTRUM

Fluctuation dynamos are generic to astrophysical systems. The only analytical model of the fluctuation dynamo is the Kazantsev model which assumes a velocity field that is delta-correlated in time. We derive a generalized model of fluctuation dynamos with finite correlation time, τ, using renovating flows. For τ → 0, we recover the standard Kazantsev equation for the evolution of longitudinal magnetic correlation, ML . To the next order in τ, the generalized equation involves third and fourth spatial derivatives of ML . It can be recast to one with at most second derivatives of ML using the Landau-Lifschitz approach. Remarkably, we then find that the magnetic power spectrum remains the Kazantsev spectrum of M(k)∝k 3/2, in the large k limit, independent of τ.

Large-scale dynamo action precedes turbulence in shearing box simulations of the magnetorotational instability

We study the dynamo generation (exponential growth) of large scale (planar averaged) fields in unstratified shearing box simulations of the magnetorotational instability (MRI). In contrast to previous studies restricted to horizontal (

Fluctuation dynamos at finite correlation times using renewing flows

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Hydraulic effects in a radiative atmosphere with ionization

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Evolution of the magnetorotational instability on initially tangled magnetic fields

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Passive scalar mixing and decay at finite correlation times in the Batchelor regime

) averaging, we demonstrate the presence of large scale fields when either horizontal or vertical (

Statistical study of magnetic field dynamics in a system of merging current filaments

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Magnetorotational Instability Can Sustain Turbulence From Tangled Small-Scale Fields

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Large scale dynamo action precedes turbulence in shearing box simulations of the magnetorotational instability

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