Disjunction drive

A concept from NASA's Breakthrough Propulsion Physics Program, the disjunction drive is based on the possibility of creating a field disjoint from the object that created it. For a simple example, picture a gigantic electromagnet a fraction of a light year away from an iron plate. The electromagnet is turned on briefly, then turned off, emitting a bit of electromagnetic radiation in the process. By the time the field reaches the plate, the magnet could even have been destroyed. Does the plate still experience a force? If so, it no longer has an object to impart an opposite force against. Similar questions arise with other forces, such as gravity: could a gravitational wave be created disjoint from its source in such a manner? It is currently unknown whether this is possible or not.