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

G. Guerrero, P. K. Smolarkiewicz, E. M. De Gouveia Dal Pino, A. G. Kosovichev, B. Zaire, N. N. Mansour

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish (US)
Pages (from-to)61-68
Number of pages8
JournalProceedings of the International Astronomical Union
Volume12
DOIs
StatePublished - 2016

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science

Keywords

  • Stars
  • Stars: dynamo
  • Stars: magnetism
  • rotation

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