Complex sentence: Two newer approaches both try to solve a problem found in the fusor, pollution of the plasma area due to collisions on the grids which spray high-mass ions into the reaction chamber and cool the fuel.
Split into simpler sentences: Two newer approaches both try to solve a problem found in the fusor, which is that some ions collide with the grids. This heats the grids, sprays high-mass ions into the reaction chamber, pollutes the plasma, and cools the fuel.