Reversals in the six-jet Geodynamo model

Abstract

Abstract. We describe a large-scale geodynamo model based on hypothesis about 6-cells convection in the Earth's core. This hypothesis suggests indirect data of inhomogeneities in the density of the Earth?s core. The convection pattern is associated with a spherical harmonic Y 2 4 which defines the basic poloidal component of velocity. The model takes into account the feedback effect of the magnetic field on convection. It was ascertained that the model contains stable regimes of field generation with reversals. The velocity of convection and the dipole component of the magnetic field are similar to the observed ones.

Symbolic Computations in Simulations of Hydromagnetic Dynamo

“…It was implemented by the authors in the Maple12 package and was successfully used to develop and study some models of geodynamo, for example [8][9][10][11]. The technology allows them to automate the routine operations for calculating the coefficients of Galerkin approximations in hydrodynamic problems and significantly increases the reliability and speed of computations.…”

Temporal regularities of changing magnetic field generation modes in the model of the αΩ-dynamo

“…where v 0 (r) is Poincare mode represented as an expansion in a hilberoth subspace such that v 0 (r)| = 1, u(t) -the velocity amplitude, B P 0,1,0 (r) -the dipole component of the magnetic field, which generates a toroidal B T 0,2,0 (r) and a poloidal B P 0,3,0 (r) components under the influence of differential rotation [3]. The velocity field and magnetic field components are considered independent.…”

“…Reversals without significant rearrangement of the motion of the conducting medium are of the great interest. The study is carried out both using direct numerical modeling, and on the basis of simplified low-dimensions models, which try to explain the physical cause, signs, and most important properties of this phenomenon [1][2][3]. In our work, we use the low-mode model αΩ-dynamo [4] to study the modes of magnetic field generation, including those with a change of polarity without convection rearrangement.…”

Reversals of the Magnetic Field in one low-dimensionalαΩ-dynamo model

“…The coefficients are chosen so that the combination approximates one of the eigenmodes of the Poincare operator . The scheme of calculation of such approximations is described in [10].…”