HR: 0800h
AN: GP21A-01    [Abstracts]
TI: Hydromagnetic Dynamos in a Non-uniformly Stratified Spherical Shell
AU: * Simkanin, J
EM: jano@ig.cas.cz
AF: Geophysical Institute, Academy of Sciences of CR, Bocni II/1401, Prague, 14131, Czech Republic
AU: Hejda, P
EM: ph@ig.cas.cz
AF: Geophysical Institute, Academy of Sciences of CR, Bocni II/1401, Prague, 14131, Czech Republic
AU: Reshetnyak, M Y
EM: reshetnyak@ifz.ru
AF: Institute of the Physics of the Earth, Russian Academy of Sciences, B. Gruzinskaya 10, Moscow, 123995, Russian Federation
AB: Magnetic fields in the universe are generated by a hydromagnetic dynamo which acts in a liquid part of their interiors. The geomagnetic field is generated similarly, i.e. by the Geodynamo action in the outer Earth's core. The outer Earth's core is probably non-uniformly stratified due to thermodynamic processes acting in this area. The most part of the outer Earth's core is unstably stratified, only very thin sublayer close to core-mantle boundary (CMB) is stratified stably. Similarly, the interiors of Giant planets are also non-uniformly stratified, especially the regions, in which the hydromagnetic dynamo action is situated. In these cases the hydromagnetic dynamo action is apparently influenced by non-uniform stratification. The numerical modelling of a hydromagnetic dynamo in a rotating non-uniformly stratified spherical shell using the control volume method is presented. Our results showed that the influence of a non-uniform stratification and viscosity to a hydromagnetic dynamo (the Geodynamo) action is slight. They are very similar to the case of an uniformly stratified spherical shell (this case will be presented for the parameters of the numerical dynamo benchmark). The generated magnetic fields are mostly dipole dominated. It is expected that the influence of a non-uniform stratification to a hydromagnetic dynamo (the Geodynamo) action will be strong in the study of turbulence.
DE: 1599 General or miscellaneous
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly