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

Observations suggest that the large-scale convective velocities obtained bysolar convection simulations might be over-estimated (convective conundrum).One plausible solution to this could be the small-scale dynamo which cannot befully resolved by global simulations. The small-scale Lorentz force suppressesthe convective motions and also the turbulent mixing of entropy between upflowsand downflows, leading to a large effective Prandtl number ($\Pr$). We explorethis idea in three-dimensional global rotating convection simulations atdifferent thermal conductivity ($\kappa$), i.e., at different $\Pr$. Inagreement with previous non-rotating simulations, the convective velocity isreduced with the increase of $\Pr$ as long as the thermal conductive flux isnegligible. A subadiabatic layer is formed near the base of the convection zonedue to continuous deposition of low entropy plumes in low-$\kappa$ simulations.The most interesting result of our low-$\kappa$ simulations is that theconvective motions are accompanied by a change in the convection structure thatis increasingly influenced by small-scale plumes. These plumes tend totransport angular momentum radially inward and thus establish an anti-solardifferential rotation, in striking contrast to the solar rotation profile. Ifsuch low diffusive plumes, driven by the radiative-surface cooling, are presentin the Sun, then our results cast doubt on the idea that a high effective $\Pr$may be a viable solution to the solar convective conundrum. Our study alsoemphasizes that any resolution of the conundrum that relies on the downwardplumes must take into account angular momentum transport as well as heattransport.

Consequences of high effective Prandtl number on solar differential rotation and convective velocity