RPF PREMIUM MEMBER
You get a better look at the hilt in this clip
I work with plasma guns and the “blade” (plume) is about an inch long, made up of ionized argon/hydrogen gas. And the support equipment is rather large, and requires 460V 3 phase @100A on the power supply.
Even if it WAS nuclear, I doubt it could fit in your hand (never mind your inability to lift it).
We need a serious technology jump to make anything like this “real”.