[Source] The reactor stalk was a long, cylindrical gas transportation conduit located underneath the main disk of Cloud City, an airborne Tibanna gas mining colony in the atmosphere of the Outer Rim gas giant, Bespin. Used as part of the city's gas mining operation, the reactor stalk acted as a conduit, transporting gas between the reactor bulb and the overhead reactor shafts. Gas mined from the lower atmosphere of Bespin by tractor beams was forced through an opening in the underside of the bulb and transported through the reactor stalk, eventually reaching the reactor shafts where processing vanes extracted the Tibanna gas.