This dissertation has been written following a full-time 6-month internship in Thales Alenia Space Cannes. It is divided in 5 main parts. The first part of the thesis introduces the fundamental concepts for the study of magnetism. Mainly Maxwell’s equations, an introduction to material science of magnetic materials as well as a presentation of FEM for magnetism from a structural engineering point of view is done. Part II serves as a rapid overview of the code developed during my internship that will be used in parts III and V. It is based on J.P Yonnet’s equations for permanent magnets. Part II doesn’t aim to re-explain all of J.P Yonnet’s theory, but merely to give some insight for the reader on the model used during the essay.