The ion cannon was a new development made by scientists of the Klingon Empire, a ship-mounted directed energy weapon utilizing ion technology, outfitted on the Klingon Negh'Var-class heavy carriers. The weapon fired a single powerful burst of energy that did a great deal of damage to enemy targets, however, once used it would take some time before the necessary power levels were restored for the weapon to be used again. (TNG game: Armada)
An ion cannon was a weapon which fired highly ionized particles or highly ionized plasma.
These particles seriously interfered with the operation of electronics and computer systems, shorting circuits and often disabling them outright. The actual physical damage would sometimes result in fused joints on machines, due to the heat produced.
Large negative-ion pulses were charged in a turbine generator then channeled into a plasma charge or released as a large pulse towards a target. As a result, ion cannons were the weapon of choice for subduing, rather than destroying, enemy starships, vehicles, shields, or droids. There are many types of ion cannons, including ground based, like the N-K7, planet based, such as the one at the Echo Hoth base, and ship mounted ion cannons, such as the one on the Malevolence.
They were often used on capital ships, such as Star Destroyers, to facilitate the capture of enemy vessels or disabling them to allow safe close-range fire. They also helped to drop shields prior to destroying enemy vessels. Fighters such as the B-wing,Y-wing, TIE/D Defender, and the Razor fighter in some cases, were also equipped with ion cannons, of much smaller size. Ships owned by bounty hunters were sometimes modified to use ion cannons,such as Boba Fett's Slave I.
A more powerful form of the ion cannon, the massive ion pulse cannon, was used in the Clone Wars, mounted on the CIS ship, the Malevolence. It was capable of disabling Venator-class Star Destroyers and could stop entire fleets in their tracks with a single shot. The weapon overloaded near the Balmorra Run thanks to the efforts of Anakin Skywalker and Ahsoka Tano.
They could also be planet-based weapons, as seen in the Battle of Hoth, where the Rebel Alliance used a stolen v-150 Planet Defender to disable the Star Destroyer Tyrant, allowing a transport to escape through the Imperial blockade.
However, there are certain types of ion cannons which are meant to do more physical damage with electrical disruption as a plus. These types of ion cannon, however, have the drawback of low firing rate and are often just replaced with heavy turbolasers.
One type of ion cannon was the Kuat V-200, used to break through shielding and bring down heavily armored vehicles. There was also a specialized version for taking down the heavily armored spacetroopers.
The Galactic Empire also experimented with ion cannons by modifying AT-ATs to become All Terrain Ion Cannons, or AT-ICs, effectively creating a mobile ion cannon. The AT-ICs saw limited action during the Galactic Civil War.
Due to their unique mission profile as a disabling weapon, ion cannons have been popular in franchise video games, particularly Star Wars: X-wing and Star Wars: Rogue Squadron, as well as their respective sequels. The representation of ion cannons in the games has been noteworthy; unlike the only appearance of the weapon in the movies, they have been seen to be largely fighter-based in the games. In another departure from the movie appearance, the discharge of an ion blast was colored cerulean blue in both series (all of which predate the blue laser bolts seen in Star Wars: Episode III: Revenge of the Sith).
Despite the real-world physics of spaceflight, disabling a craft with ion cannons in the X-wing series of games had the effect of stopping it dead in space rather than simply crippling its flight control system. Contradictorily, the use of a Y-wing starfighter's ion cannons to disable Kasan Moor's TIE/In interceptor just above the surface of Gerrard V in a cutscene appeared to disable the Imperial craft's flight control systems, but not its engine system, resulting in the interceptor flying in a straight line without being able to deviate from its course.
Ion cannons were a form of weapon primarily used on starships.