[Source] The reactor bulb was a large, spherical gas intake device located at the bottom 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, tractor beams converging below the bulb worked together to create an energy funnel that mined gas from Bespin's lower atmosphere and transported it up to the bulb, where it was forced through an intake on the underside. From there the gas traveled up the reactor stalk and into several reactor shafts where it was filtered through processing vanes.