As you see, this is the electric field generated by a point charge moving at constant speed v. I know that when $v$ -> 0, $E$ is just the Coloumb Law. But how do you interpret $E$ when $v$ -> $c$ ?
Can I just interpret it as the field of electromagnetic wave, because it moves at the speed of light?
Moving charges don't emit electromagnetic waves unless they are accelerating. A charge moving at a constant speed will just have a field that moves with it, but not a propagating field (i.e., electromagnetic waves).
Sources: Introduction to Electrodynamics by David J Griffiths 4th edition, section 10.3.2 and example 10.4 (pages 459-461), or the Wikipedia page for the Liénard-Wichart Potential.
