  A good understanding of the confinement of energetic ions in non-axisymmetric
magnetic fields is key for the design of reactors based on the stellarator
concept. In this work, we develop a model that, based on the radially-local
bounce-averaged drift-kinetic equation, classifies orbits and succeeds in
predicting configuration-dependent aspects of the prompt losses of energetic
ions in stellarators. Such a model could in turn be employed in the
optimization stage of the design of new devices.
