title: Relativistic E x B acceleration.
abstract: The relativistic motion of charged particles is analyzed theoretically in electric and magnetic fields that are constant, uniform, and mutually perpendicular. In the relativistic regime where the magnitude of the electric field E is equal to or greater than that of the magnetic field B, i.e., |E| > or =|B|, the particle is effectively accelerated and gains energy indefinitely. This is quite different from the E x B drift motion in the nonrelativistic regime.