If the Na'vi see such things in the sequels, they might equate light, or lightening, or bioluminous qualities along with shapes, or sounds. They might have words that resemble storm noises or names. When early Earth civilizations encountered new things, they used words they already had to describe it. The
world-wide-web is not made by spiders, and there are no
horses pulling automobiles but they are a part of how we describe their power.
Plasma ~ depending on how it was observed might be equated to lava, or smoke, or a variation of fire.
Ray + Laser ~ Lightening sound metal stick/tree-limb/tree-branch. Many of the beam weapons would be lumped together, since only an advanced technological society would know or care about the differences. The RDA did not use these things in the fight, but that could be caused by regulations they had to follow.
Radiation ~ most likely would only be thought of in the context of poison or heat. Even if they have uranium ore, or an equivalent on Pandora, and if the Na'vi ever came near any, they might use it to make yellow glaze to their ceramics like persons did on Earth around 79 CE. Living over Uranium deposits can cause exposure to radon gas, so it could be thought of in that context. Also, it glows in the dark, it could be a night luminous color word for the uranium ores with a kinship to green.
Antimatter + Nuclear + Fusion + Electromagnetic ~ would be borrowed words if they are ever used at all.
Cannon ~ if observed would likely be onomatopoeia like machine gun, or laughing.
