Gravity lift
From Halopedia, the Halo wiki
The Gravity Lift is Covenant graviton technology used to either levitate objects into the air via an amethyst, sparking circular beam that is refractive to plasma, or As the name implies, it uses artifical gravity to move troops and supplies up and down through levels, or from a ship to the planet suface. Gravity lifts are also used for Deployable Lookout Towers. Gravity Lifts appear as transparent purple-hued cylinders of light. Gravity Lifts are seen twice in the game Halo: Combat Evolved. These scenes both involve the Master Chief and the Covenant CCS-class battlecruiser Truth and Reconciliation, which can be seen projecting the lifts in the levels Truth and Reconciliation and Keyes.
