The research being reported on, involves particle beams of tantalum. What if the objective involves more of an orbital beam weapon?
What effect would a beam of tantalum atoms, moving at a good percentage of the speed of light, have on satellites? Or ICBM warheads or electronics?
Having worked with heavy ion accelerators for 6 years in the '80s (material science applications, all very benign), this is the best I've got: There is no relevance of those "superheated beams" to nuclear weaponry.
To make a particle beam, a small amount of the substance is heated in a vacuum chamber to a temperature above the melting and then evaporation point (a few thousand degrees, depending on the metal). The gaseous atoms are then stripped of one or more of their outer shell electrons - ionized - and subjected to a high voltage electric field, which accelerates the ions in the direction of the field, hence creating the "beam".
The number of ionized atoms in said beam - the "fluence" - is so low (realistically in the order of 10-15 ampere) that it is inconceivable to be used as a weapon. Never mind that all this has to happen in an enclosed high vacuum environment.
I think that the author is not at all clear about the physics involved in that statement of his and the implications he draws therefrom.