Cherenkov-like shock waves associated with surpassing the light velocity barrier

The effects arising from the accelerated and decelerated motion of a point charge inside a medium are studied. The motion is manifestly relativistic and may be produced by a constant uniform electric field. It is shown that in addition to the bremsstrahlung and Cherenkov shock waves, the electromagnetic shock wave arises when the charged-particle velocity coincides with the light velocity in the medium. For the accelerated motion, this shock wave, forming an indivisible entity with the Cherenkov shock wave, arrives after the arrival of the brernsstrahlung shock wave. For the decelerated motion the above shock wave detaches from the charge at the moment when its velocity coincides with the light velocity in the medium. This wave, existing even after termination of the charge motion, propagates with the velocity of light in the medium. It has the same singularity as the Cherenkov shock wave and is more singular than the brernsstrahlung shock wave. The space-time regions, where these shock waves exist, and conditions under which they can be observed are determined.