In high energy physics and space applications it becomes mandatory to solve specific problems concerning the power supply. In both cases, it exists a harsh radiation environment and the presence of external electromagnetic perturbations. The former prevents the use of standard technology and many studies on this subject were already made. Solutions foresee the use of ad-hoc technologies or the modification of the layout of standard technologies. The latter causes problems concerning the magnetic elements used in many switching power supply topology. The aim of this study is the analysis of the magnetic components necessary in these circuits, their environmental constrains and their evaluations through simulations and practical tests in order to show up which geometry is preferable to limit injection of noise and to increase the efficiency. © 2008 IEEE.