Are you speaking of an electro-magnetic pulse weapon, an EMP?
There's no evidence that an actual weapon exists. There are only reports of the United States and others testing them and developing them, partially for potentially offensive reasons or for defensive reasons. There is a long range of different types of weapons that you can imagine being deployed in outer space. These are potential dual-use technologies coming out of the civilian sector that are then going to be transferred into the military sector.
You would need to talk to a scientist about how you would actually use them, because I don't know how they would use them. I've learned over my years to stop trusting what scientists tell me.