Directed-energy weapon

A directed energy weapon (or DEW) is a type of weapon that uses a non-solid projectile with a high enthalpy (kinetic and thermal energy) rather than solid ballistic ammunition. It transfers energy to a target for a desired effect.

Lasers


Lasers are used for a wide array of functions, ranging from repair equipment to weaponry. Pulse Lasers are standard armament on Covenant warships and, unusually, UNSC Prowlers, and are used for precision strikes against small targets, intercepting incoming missiles and fighters, and general point-defense. Other lasers are used to repair equipment by both the Covenant and the UNSC, while the only infantry-portable laser weapon is used by the UNSC, the Galilean Nonlinear Rifle or "Spartan Laser".

Plasma


The Covenant's most common weapon type, however, is superheated plasma that is contained within a controlled magnetic field, able to be guided to a target and dealing heavy damage. Ship-mounted plasma weapons can launch torpedoes, capable of tracking their targets with precision, making them devastating in ship-to-ship combat, or can fire very large streams of plasma from afar to "glass" a planet's surface from orbit. Vehicle-mounted plasma weapons usually have a high rate of fire, but lack the guidance systems. Infantry weapons commonly use guided plasma, such as the Plasma Rifle, Plasma Pistol, and the Plasma Grenade.

Sentinels use a powerful continuously-firing plasma beam called the Sentinel Beam as their main weapon.

Particle Beam Weapons


The Covenant also use accelerated particles as weaponry, such as the devastating capitol-ship mounted Energy Projector and the infantry Type-50 Sniper Rifle System. These weapons use charged or neutral particles, and may appear similar to lasers though the differences are extensive. Though humans have an understanding of accelerated particle technology they have not yet used it for weaponry.

As of the early 21st century, humanity had developed particle accelerators, but the machinery needed to work one is massive.