Back of the envelope, when you add up all the generators and capacitors needed to provide the electrical whallop needed, I'd say you are about right. The capacitors alone could weight thousands of pounds. I have done some VERY powerful strobe photography (did you know you can photograph nuclear explosions in their very early stages?) and the caps I used rolled on large carts, about the size of chest freezers but MUCH heavier.
They're doing some interesting things with chemically-driven lasers that can generate extremely powerful pulses of short duration; it's not impossible that such charges could be arranged in a series to get the job done, but not in the immediate near future- I think. Whether such output would be better utilized in laser weaponry, in a rail gun, or some other development depends on research and breakthroughs in those fields, but I wouldn't sell any of them short. I'm reminded of the naval explosives expert who testified that atomic weapons were a scientific impossibility...until, of course, the Manhattan Project delivered. I wonder if that guy was just short-sighted, or a part of a disinformation program....
I know they did some real interesting things with spark photography so far as documenting early stages of a nuclear detonation, but that's way beyond my limited knowledge in the field. I've also seen some of the caps [still called *condensers* then] that came out of the Camp Hero site at Montauk, LI; some were about the size of a Volkswagon.