Energy torpedo
From Wookieepedia, the Star Wars wiki.
The energy torpedo was a variant of the normal plasma weapons. It was made of some fusion plasma which was shot into a magnetic bottle at the target. The magnetic field which contained the plasma could not hold it together more than a minute, but because of the speed of the energy torpedo it could cover a huge distance in this time.
An energy torpedo was a kind of missile with an unlimited supply of ammunition. Their missing intelligence (the energy torpedo only flew in a straight line), the huge weight of the launcher and the long recharge time prevented the energy torpedo from becoming a standard weapon. The recharge time of a light torpedo was 30 seconds, medium ones had a recharge time of 45 seconds and the large energy torpedo launchers needed one minute to recharge. The speed of an energy torpedo was 20% the speed of light in addition to the firing ship's movement in the direction of launch.
Because of its unfocused nature, energy torpedoes could only weaken enemy shields by half. They could be detonated by point defense fire, but because they did not contain solid matter one would need a lot of firepower to do so.
Vulture droid starfighters were equipped with two energy torpedo launchers.
