Ion drive

The Ion drive was a type of engine technology used to propel most starships at sublight velocities. Ion engines were fueled by power cells, liquid chemical reactants, onboard generators, or virtually any other device capable of providing sufficient power. The engine utilized internal fusion reactions to produce a stream of highly-charged particles that were forced through the engine's exhaust port at nearly the speed of light. Ion engines were sometimes called ion rockets.

Ion engines were known to emit mildly radioactive byproducts, requiring onboard technicians to wear protective gear. Because of this radioactivity, it was common protocol for most ships to utilize repulsorlifts for propulsion during atmospheric flight and reserve use of the more powerful ion drives for orbital navigation.

The most noted craft using ion drives were TIE Fighters, who received their name in accordance with the number of ion engines they used: Twin Ion Engine.

Replacement Drives

 * Arakyd H-L Block ion drive
 * Boshaa-C'hi Ion Drive
 * Corellian Evader-GT Ion Drive
 * Incom Starslinger Ion Drive
 * SoroSuub Boav Ion Drive
 * Starscream-9 Ion Drive

Behind the scenes
Ion drives are becoming science fact on Earth as the first successful test of the Dawn spacecraft's ion engines used xenon propellant. It burned for 27 hours and only expended 10 ounces of fuel. 

Appearances
Virtually all known Star Wars material.

Below is a list of novels where ion drives are mentioned directly:
 * Boba Fett: Crossfire
 * Labyrinth of Evil
 * Dark Lord: The Rise of Darth Vader
 * Coruscant Nights I: Jedi Twilight
 * Star Wars 5: Lo, The Moons of Yavin
 * Vector Prime
 * Edge of Victory II: Rebirth