I've learnt an electromagnetic field is produced by moving charges, i.e. a current.
Is it the case, or is it actually the fact that the charge is changing at a given location?
I mean: imagine I have a charge $q_1$ located at a given point of the space. Then imagine the charge changes and becomes $q_2$, but without moving (this is probably impossible? but let's imagine). Does it produce an electromagnetic field?
Or, without "imagining" a charge changes over time:
Is the EM field produced by the movement of the charge, of by the fact the charge vanishes from its location?