Jaxon Hamilton

2022-07-19

If a charge moving at constant velocity doesn't produce EM waves, how does it create an EM field in a point in space if the charge and the point can communicate only via EM waves?

kuglatid4

Expert

If a charge is moving at constant velocity for inertial frame $A$, it is always possible to make a change of coordinates, applying Lorentz transformation, to the inertial frame of the particle, say $A$.
For frame $A$, the field is static all over the space. And frame $A$ is moving around this static field. So, there is no signal or information to be transmitted.
Of course we can think that the charge was not always there. At some moment a device separated positive and negative charges, and surely some acceleration was involved. EM waves were emitted then, sending the information through the space.

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