Electric field of a point charge in truncated hyperbolic motion

Abstract

We find the electric field of a point charge in ‘truncated hyperbolic motion’, in which the charge moves at a constant velocity followed by motion with a constant acceleration in its instantaneous rest frame. The same Lienard–Wiechert formula holds for the acceleration phase and the constant velocity phase of the charge’s motion. The only modification is that the formula giving the retarded time is different for the constant velocity motion than it was for the accelerated motion. The electric field lines are continuous as the retarded time increases through the transition time between constant velocity and accelerated motion. As the transition time approaches negative infinity the electric field develops a delta function contribution that has been introduced by others as necessary to preserve Gauss’s law for the electric field.