A Directed Energy Weapon (or DEW) is a type of weapon that uses a non-solid projectile with a high enthalpy (kinetic and thermal) rather than solid ballistic ammunition. It transfers energy to a target for a desired effect. In the real world, some of these weapons are real or in development; others are, at present, only science fiction.
Lasers
- Main article: Light Amplification by Stimulated Emission of Radiation
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, to UNSC Prowlers, and are used for precision strikes against small targets, intercepting incoming missiles and fighters[1], and general point-defense. Other lasers are used to repair equipment by both the Covenant[2] and the UNSC[3], while the only infantry-portable laser weapon is used by the UNSC, the Galilean Nonlinear Rifle or "Spartan Laser".
Sentinels use a powerful continuous firing laser called the Sentinel Beam as their main weapons.
Plasma
- Main article: Plasma Weaponry
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.
Particle Beam Weapons
- Main article: Particle Beam Weapon
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.