A thermodynamical model for paleomagnetism in Earth's crust

A thermodynamically consistent model for soft deformable viscoelastic magnets is formulated in actual space (Eulerian) coordinates. The possibility of a ferro-paramagnetic-type (or ferri-antiferromagnetic) transition exploiting the Landau phase-transition theory as well as mechanical melting or solidification is considered, being motivated and applicable to paleomagnetism (involving both thermo- and isothermal and viscous remanent magnetization) in rocks in Earth's crust and to rock-magma transition. The temperature-dependent Jeffreys rheology in the deviatoric part combined with the Kelvin-Voigt rheology in the spherical (volumetric) part is used. The energy balance and the entropy imbalance behind the model are demonstrated, and its analysis is performed by time discretization, proving existence of weak solutions.

Automated summary

A thermodynamically consistent model for soft deformable viscoelastic magnets is proposed in this paper, formulated in actual space coordinates. The model considers the possibility of a ferro-paramagnetic-type or ferri-antiferromagnetic transition using Landau phase-transition theory, as well as mechanical melting or solidification, which is motivated and applicable to paleomagnetism in rocks in Earth's crust and to rock-magma transition.