Dynamo seeds

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  • IDEX UCAJedi
Published on September 28, 2022 Updated on September 29, 2022
Dates

on the September 29, 2022

A quasi-Keplerian dynamo
A quasi-Keplerian dynamo A quasi-Keplerian dynamo

Find out about an Inria and CNRS joint research project that is taking advantage of the Azzurra HPC cluster


The animation below shows a finite-amplitude magnetic seed triggering a subcritical dynamo instability through the magnetorotational instability (MRI) in a quasi-Keplerian shear flow. This flow is used here as a simplified model to study the possible mechanisms for magnetic field generation in accretion discs.

The volume rendering shows the streamwise (azimuthal) component of the magnetic field. The cross section shows surface line integrals highlighting the structure of the transverse (meridional) magnetic fields. The initial seed field, being essentially transverse and streamwise invariant, is rapidly wound up by the base flow's shear, generating a large-scale streamwise magnetic field. The latter destabilises upon exceeding a critical amplitude, giving rise to a self-sustained, fully 3D dynamo state. Further details including source code and initial conditions are given in [1].

The Azzura HPC center provides us with the required computing resources, technical support and dedicated job queues for the targeted simulations necessary to enable rapid progress. Similarly, the massively parallel open source pseudo-spectral code Dedalus [2] provided us with the simulation tools to make such an endeavour feasible.

This project was supported by the Agence Nationale de la Recherche

(Grant No. ANR-19-ERC7-0008, DynSeed project).

[1] https://doi.org/10.1103/PhysRevLett.129.024502

[2] https://dedalus-project.org/index.html

Authors

  • Paul Mannix, Université Côte d'Azur, Inria, CNRS, LJAD, France
  • Yannick Ponty, Université Côte d'Azur, CNRS, Observatoire de la Côte d'Azur, Laboratoire Lagrange, France
  • Florence Marcotte, Université Côte d'Azur, Inria, CNRS, LJAD, France