Complex sentence: It is one of a number of types of reactor, based on inertial electrostatic confinement, which use an electric field to accelerate charged ions and heat them to conditions suitable for nuclear fusion.
Split into simpler sentences: It is one of a number of types of reactor that are based on inertial electrostatic confinement. These types of reactors use an electric field to accelerate charged ions, and heat them to conditions suitable for nuclear fusion.