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

Autor(es)

Guerrero, G. ; Smolarkiewicz, P. K. ; de Gouveia Dal Pino, E. M. ; Kosovichev, A. G. ; Zaire, B. ; Mansour, N. N. ; Nandy, D ; Valio, A ; Petit, P

• Tipo de documento: Artigo Científico
• Fonte: LIVING AROUND ACTIVE STARS; v. 12, n. S328, p. 8-pg., 2017-01-01.

Resumo

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. (AU)

• Processo FAPESP: 13/10559-5 - Investigação de fenômenos de altas energias e plasmas astrofísicos: teoria, simulações numéricas, observações e desenvolvimento de instrumentação para o Cherenkov Telescope Array (CTA)
• Beneficiário: Elisabete Maria de Gouveia Dal Pino
• Modalidade de apoio: Auxílio à Pesquisa - Projetos Especiais