Are tachoclines important for solar and stellar dynamos? What can we learn from global simulations

Document Type

Conference Proceeding

Publication Date

1-1-2016

Abstract

The role of tachoclines, the thin shear layers that separate solid body from differential rotation in the interior of late-type stars, in stellar dynamos is still controversial. In this work we discuss their relevance in view of recent results from global dynamo simulations performed with the EULAG-MHD code. The models have solar-like stratification and different rotation rates (i.e., different Rossby number). Three arguments supporting the key role of tachoclines are presented: the solar dynamo cycle period, the origin of torsional oscillations and the scaling law of stellar magnetic fields as function of the Rossby number. This scaling shows a regime where the field strength increases with the rotation and a saturated regime for fast rotating stars. These properties are better reproduced by models that consider the convection zone and a fraction of the radiative core, naturally developing a tachocline, than by those that consider only the convection zone.

Identifier

85030083985 (Scopus)

Publication Title

Proceedings of the International Astronomical Union

External Full Text Location

https://doi.org/10.1017/S1743921317003982

e-ISSN

17439221

ISSN

17439213

First Page

61

Last Page

68

Volume

12

Grant

320375

Fund Ref

National Aeronautics and Space Administration

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