Ion thrusters, also known as ion propulsion systems or ion drives, operate on the principle of accelerating ions (usually xenon) to generate thrust. These engines are commonly used in spacecraft for long-duration missions due to their high specific impulse. Control volume analysis, as traditionally used in fluid dynamics, may not be directly applicable to ion thrusters. Instead, the thrust can be explained using the basic principles of electrostatics and conservation of momentum.
Ion thrusters ionize propellant, typically xenon gas, and then use electric and/or magnetic fields to accelerate the ions to high velocities. The high velocity of the ions produces thrust as they are expelled from the spacecraft.
The thrust force () in an ion thruster can be expressed by the basic rocket equation:
where,
- is the thrust force,
- ṁe is the mass flow rate of exhaust gases in kilograms per second (kg/s).
- is the Exhaust velocity at the nozzle exit in meters per second (m/s).