Ion Engines
An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft movement. It generates thrust by accelerating ions using electricity. The ion thruster ionizes neutral gas by stripping some electrons from atoms, creating a cloud of positive ions.
The operating principle of ion engines is primarily based on electrostatics, as the ions are accelerated along an electric field by the Coulomb force. Temporarily stored electrons are eventually recombined with the ion cloud by a neutralizer after passing through the electrostatic grid, neutralizing the gas so it can freely disperse in space without any electrical interaction with the thruster.
In contrast, electromagnetic thrusters use the Lorentz force to accelerate all types of charged particles (free electrons as well as positive and negative ions) in the same direction, regardless of their electric charge. In regions where there is no electric field, these are referred to as plasma propulsion engines.