This is the FLAK class Anti-fighter Cannon. It is one of the simplest weapons used onboard Operation Phoenix ships. It is specialized to deliver enough defensive firepower to clear waves of incoming fighters.
They have no stationary parts. It is comprised of piezo-electric cells, a C-60 nanotubule shell and electromagnetic coils. The piezo-electric cells contract when an electric applied. Each cannon is manipulated so that it makes fluid movements offering a large firing arc. The mechanism acts much like an arm, but without the limitations of movement caused by muscle and ligament tissue.
The weapon fires relatively small mass packet at a velocity of 30,000,000 m/s. Though these masses are small and would hardly dent a capital ship, the delacate workings of a fighter, especially those made vulnerable by glass cockpits. These emplacements are positioned every several metres along the hull of the ship allowing for total coverage. When inactive, the arms can simply retract to be only a few centimetres from the hull's surface.