English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We carry out systematic and high-resolution studies of dynamo action in ashell model for magnetohydrodynamic (MHD) turbulence over wide ranges of themagnetic Prandtl number $Pr_{\rm M}$ and the magnetic Reynolds number $Re_{\rmM}$. Our study suggests that it is natural to think of dynamo onset as anonequilibrium, first-order phase transition between two different turbulent,but statistically steady, states. The ratio of the magnetic and kineticenergies is a convenient order parameter for this transition. By using thisorder parameter, we obtain the stability diagram (or nonequilibrium phasediagram) for dynamo formation in our MHD shell model in the $(Pr^{-1}_{\rm M},Re_{\rm M})$ plane. The dynamo boundary, which separates dynamo and no-dynamoregions, appears to have a fractal character. We obtain hysteretic behavior ofthe order parameter across this boundary and suggestions of nucleation-typephenomena.

Dynamo Onset as a First-Order Transition: Lessons from a Shell Model for Magnetohydrodynamics