Beam emitter

For other uses of the term beam, see here. A beam emitter is a Forerunner device or structure that, as the name implies, emits beams of energy. Though applied for many purposes, they are generally used to transport enormous amounts of energy from one location to another, serving as sophisticated power conduits. The beams may be constant, feeding a steady stream of energy to a certain system such as an energy barrier, or momentarily channel the energy required in the activation of an installation. Perhaps the most ubiquitous usage of beam emitters is found in beacon towers, monolithic structures found on many Forerunner worlds, but most notably on each installation in the Halo Array.

Beacon towers
Beacon towers are large delta-shaped structures with a cleave down the approximate center where a beam is emitted. They fire beams upwards—in the case of the Halo installations, they fire toward the center of the ring, and in the case of Installation 00, they simply fire up into space.

Beacon towers can serve several uses. On Requiem, beacon towers are used as stations for delivering navigation data and function as part of the shield world's teleportation grid, featuring teleportation portals that can transport objects to various other parts of the installation. On Installation 07, the beacon towers are designed to channel, convert, and refine energy streams of virtually any type. The Halo's beacon towers assist in ring-wide communication and also aid in the activation process of the installation primary weapon, among a multitude of other purposes.

The beacon towers can be used to send superluminal messages into space. A data key generated by 117649 Despondent Pyre performed a security override on one of Zeta Halo's beacon towers to remove the lockout that Cortana had placed upon it before then using adaptation protocols to instruct the tower to send a superluminal message into human-occupied space with the ring's current galactic coordinates and the site's pertinent data.

Other types
The Control Rooms of the Halo installations possess a type of beam emitter, which fires a continuous beam from the depths of the Control Room to the top of the structure, and into the center of the ring when the installation is activated. In case the firing sequence is canceled, like on Installation 05, the beam collects into a large bolt of energy, which is then fired into the center of the ring, causing the energy collected in the center to dissipate.

The Ark Portal in Kenya also has a type of beam emitter, which discharges a concentrated beam to the sky when the portal is activated. In addition, the Apex Site on Trove also possessed a beam emitter. Continuous beams of energy are also channeled through the phase pulse generators used to control the firing systems of the Halo rings. In High Charity, the Covenant used a conduit of energy to connect the Forerunner Dreadnought's engines into the city's power grid.

Around Installation 00's Citadel, three barrier towers featuring beam emitters were used to project an energy barrier that surrounded the Citadel. The weather spires on the Halo rings also feature beam emitters.

Trivia

 * If the player manages to stand at the top of a beam tower, over the chute in which the beam shoots from, the beam can either kill him/her, sending the player over a hundred feet in the air, or completely pass through the player. When killed by the beam, it will say "(Player) was killed by the Guardians". In Halo 3, however, the beams coming from the beam emitters (except in Valhalla) will not kill the player, no matter what. This is most likely due to gameplay reasons.
 * Beam emitters are objectives to be captured the Domination multiplayer mode of Halo Wars 2.

List of appearances

 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo 2
 * Halo 3
 * Halo Wars
 * Halo: Reach
 * Halo: Combat Evolved Anniversary
 * Halo 4
 * Spartan Ops
 * Halo 2: Anniversary
 * Halo 5: Guardians
 * Halo Wars 2
 * Halo Infinite
 * Halo: The Rubicon Protocol