Gravity plasma confinement. That would be possible in the gtva level of technology. Each of the fighters operates like a herrier except with anti grav(something V spilled the beans on). Besides that, there vessels are obviously capable of artificial gravity or else you see everyone flying around the debriefing room which would be really funny.
So far the future of plasma weapons in realistic terms is still magnetic confinement, hell it still would be for the gtva tech also. Gravity technology is a complicated tech, that's if you guys have read about that old soviet scientific test a while ago where a dude used a superconductor to partially bypass gravity and remove some of the weight from say a coin.
It would most likely go along the lines of magnetic confinement for the first generation of plasma weapons, and later on relied on pretty much for the more basic of plasma weapons. Gravity confinement for plasma is a lot more advanced and difficult, but you could do so much more with plasma in gravity confinement, you could make a much bigger and destructive weapon, more specialized, etc. Gravity confinement plasma weapons would definitely be for the more destructive, sophisticated, manipulative, and beautiful show off of plasma manipulation.