Beam emitter

Beam Emitters are large delta-shaped, tower-like structures on Halo with a cleave down the approximate center. They fire unknown beams upwards, in the case of the Halos to the center, and in the case of the Ark up into space. They are likely used to transport energy for the activation process of the Halo rings. They can be seen in the Halo: Combat Evolved level, Halo, and on the Halo: Combat Evolved cover. Similar structures that most likely share the same purpose can be seen in the Halo 3 multiplayer map Valhalla and in the Halo 2 multiplayer level Relic.

If you manage to stand at the top of the chute in which the beam shoots from, the beam can either kill you, sending you over a hundred feet in the air, or completely pass through you.

It is possible that the beams visible during the campaign of HALO: Combat Evolved are simulated firings of Alpha Halo.