Complex sentence: The polywell is a type of nuclear fusion reactor, based on inertial electrostatic confinement, in which an electric field is used to accelerate charged ions, and heat them to conditions suitable for nuclear fusion.
Split into simpler sentences: The polywell is a type of nuclear fusion reactor that is based on inertial electrostatic confinement. In inertial electrostatic confinement, an electric field is used to accelerate charged ions, and heat them to conditions suitable for nuclear fusion.