Open AccessHydromagnetic dynamos in rotating spherical fluid shells in dependence on the Prandtl number, density stratification and electromagnetic boundary conditions
Author(s) -
Tomáš Šoltis,
Ján Šimkanin
Publication year - 2014
Publication title -
contributions to geophysics and geodesy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.235
H-Index - 18
eISSN - 1338-0540
pISSN - 1335-2806
DOI - 10.1515/congeo-2015-0007
Subject(s) - magnetic prandtl number , dynamo , prandtl number , stratification (seeds) , physics , magnetic field , mechanics , condensed matter physics , magnetic reynolds number , dynamo theory , magnetohydrodynamics , classical mechanics , reynolds number , convection , turbulence , nusselt number , germination , botany , quantum mechanics , dormancy , biology , seed dormancy
We present an investigation of dynamo in a simultaneous dependence on the non-uniform stratification, electrical conductivity of the inner core and the Prandtl number. Computations are performed using the MAG dynamo code. In all the investigated cases, the generated magnetic fields are dipolar. Our results show that the dynamos, especially magnetic field structures, are independent in our investigated cases on the electrical conductivity of the inner core. This is in agreement with results obtained in previous analyses. The influence of non-uniform stratification is for our parameters weak, which is understandable because most of the shell is unstably stratified, and the stably stratified region is only a thin layer near the CMB. The teleconvection is not observed in our study. However, the influence of the Prandtl number is strong. The generated magnetic fields do not become weak in the polar regions because the magnetic field inside the tangent cylinder is always regenerated due to the weak magnetic diffusion.