Some Inverse Problems in Geomagnetism
Salle Byron Blanc (rez de chaussée) – September 5, 2016 at 2:00 PM.
In this talk we give a brief introduction into the different components of the Earth’s magnetic field and describe some related inverse problems in more detail. In particular, we focus on problems involving the reconstruction of magnetizations from magnetic field measurements. Generally, magnetic field measurements are given (globally) on a sphere at about 400km above the Earth’s surface (satellite measurements) or on parts of a sphere at a few kilometers above the Earth’s surface (aeromagnetic measurements). The reconstruction of the magnetization is non-unique but localization constraints can improve the non-uniqueness issues to a certain extent. We want to discuss how such localization constraints can help (i) to reconstruct dipole directions when we assume that the magnetization is induced by a central dipole magnetic field with unknown dipole direction and (ii) to separate magnetic fields that are due to crustal magnetizations from those that are due to physical processes in the Earth’s outer core when only the superposition of the two fields is known.