A chaotic gun effect for relativistic charged particles

We study in this paper the motion of a charged particle in a field of a transverse monochromatic electromagnetic wave and within a constant external magnetic field. A new phenomenon, the chaotic gun effect, is discovered if the amplitude of the wave is sufficiently large. It is shown that a high acceleration of charged particles is obtained by a cascade of gun effects which lead to sudden jumps between phase Larmor circles. Numerical experiments display a clear energy dependence of the time of escape of particles as they exit from the acceleration region. This result appears important for laboratory and space research experiments on particle acceleration.