Unlimited acceleration of a charged particle by an electromagnetic wave

It is shown that a charged particle can be trapped in a magnetic neutral sheet produced by a static magnetic field B vector0 and an electromagnetic wave propagating perpendicularly to B vector0. The neutral sheet as well as the trapped particle moves with the phase velocity Vp and the trapped particle feels a constant force qγpVpB0/c along the neutral sheet, q, c and γp being the charge, the velocity of light and (1-Vp2/c2)-1/2. Once the particle is trapped it never detraps and then the acceleration continues unlimitedly. A brief discussion is given on how to realize such a slow electromagnetic wave which can interact with the particle. (author)