Introducing FENNEC: a Framework for Easy Numeration in NEar-spherical Configurations. Applications to core dynamics.

The modelling of planetary dynamics very often relies on the numerical resolution of systems of PDEs in spherical/Clairaut and/or spheroidal coordinates. The process of discretising such problems can be a daunting task and calls for many intermediate steps that must be repeated whenever one wishes to modify or expand on the original model. Here we present a tool to automate those steps thus allowing the user to concentrate on actual physics. The discretisation is based on an efficient full spectral decomposition leading to a highly sparse matrix representation. We demonstrate its use in the resolution of various problems of fluid core dynamics.