A charged composite particle in a constant electric field

We consider the motion of a composite charged particle in a constant electric field. Using the billiard formalism, we establish exact laws of motion for such a particle with a small number of internal degrees of freedom and propose using a generalized Schwarz principle to straighten trajectories in the field presence. Within the billiard formalism, we obtain regimes of motion of a composite particle with two internal degrees of freedom in a constant field.