2007/05/25 by K. Brendel, Kevin Brendel, J. Kuipers +2
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Amplitude #Computational physics #Diffusion #Dipole #Earth's magnetic field #Geomagnetism and Paleomagnetism Studies #Geophysical and Geoelectrical Methods #Magnetic dipole #Magnetic field #Physics #Quantum electrodynamics #Quantum mechanics #Solar and Space Plasma Dynamics #Statistical physics #physics.geo-ph
paper · pdf · doi:10.1016/j.pepi.2007.05.005
published as Phys. Earth Planet. Inter. 162 (2007) 249-255 · 11 pages, 6 figures
openalex publication_date 2007/05/25 · arxiv created 2007/07/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The time evolution of the strength of the Earth's virtual axial dipole moment (VADM) is analyzed by relating it to the Fokker-Planck equation, which describes a random walk with VADM-dependent drift and diffusion coefficients. We demonstrate first that our method is able to retrieve the correct shape of the drift and diffusion coefficients from a time series generated by a test model. Analysis of the Sint-2000 data shows that the geomagnetic dipole mode has a linear growth time of 13 to 33 kyr, and that the nonlinear quenching of the growth rate follows a quadratic function of the type [1-(x/x0)2]. On theoretical grounds, the diffusive motion of the VADM is expected to be driven by multiplicative noise, and the corresponding diffusion coefficient to scale quadratically with dipole strength. However, analysis of the Sint-2000 VADM data reveals a diffusion which depends only very weakly on the dipole strength. This may indicate that the magnetic field quenches the amplitude of the turbulent velocity in the Earth's outer core.