Plasma weapons contain and guide the plasma in the form of a single bolt, beam, or continuous stream. Plasma is stabilized using magnetic fields. Without the field, the plasma dissipates too quickly to be of any real use. The field controls and contains the plasma, without interfering with firing. The energy sword is an example of this technology, as the magnetic field holds the blade together while allowing it to cut through objects.
This is also how the plasma pistol's overcharge shot works: A small magnetic generator is installed in the hilt of the pistol and, when fired, the bolt tracks its target using a very simple motion tracking system built into the magnetic generator which alters the field to make the plasma move. A larger version of this effect is seen in the plasma torpedoes used by Covenant capital ships.
Defense against plasma weaponry
Complete armor protection against plasma is generally difficult to accomplish due to plasma's high damage ratio. The armor used by the UNSC Marine Corps and UNSC Army usually provides good protection from plasma, but only to a certain extent. A series of hits from a plasma weapon will literally melt or burn the armor, rendering it useless. Likewise, the Spartans' MJOLNIR armor will eventually give way to the plasma. Newer versions of the MJOLNIR armor boast energy shields, which provide additional protection from plasma, although shielding systems can be completely depleted by sustained plasma fire, or a single, overcharged bolt.
The armor of neither Covenant nor UNSC warships provides significant protection against plasma, which will melt through the hulls of both. Covenant plasma torpedoes have a temperature of approximately 3,000 degrees Celsius, while titanium, a key component of UNSC ship armor, has a melting point of 1668 degrees Celsius.[note 1] In all encounters with Covenant ships, plasma-based weaponry has melted through and disabled UNSC ships in a matter of seconds.
Plasma-based weapons are the most common armament of Covenant infantry and vehicular forces, and the main armament of their warships, dominating almost their entire weapon arsenal. Small arms are designed to deplete shielding or melt infantry armor, while heavier weapons can destroy vehicles or buildings. The largest are mounted onto capital ships and are used for orbital bombardment and ship-to-ship combat, and can reduce a ship's hull to a pile of molten metal floating in space. When a plasma weapon is charging, a high quantity of beta particle radiation is emitted. Covenant species have developed a natural resistance against the radiation emitted by their plasma weapons, a form of "forced evolution". During the Human-Covenant War, UNSC scientists studied this phenomenon in an attempt to use it to their advantage, such as helping in the treatment of plasma burns on humans.
The UNSC has yet to develop its own plasma weaponry, instead using more conventional projectile-based weapon systems. However, the UNSC has been seen to operate captured Covenant plasma weapons, and in one case, UNSC forces were able to dramatically improve the lethality of a captured Covenant starship's plasma turrets without significant technical modifications. There was an attempt to produce a tank with plasma-based weaponry for the UNSC armed services, but it was abandoned, falling back on projectile weaponry.
List of plasma weapons
- Focus cannon
- Plasma mortar
- Class-1 directed energy cannon
- Class-2 directed energy cannon
- Heavy plasma cannon
- Type-27 Mantis AAC
- Type-38 Tyrant AAC
- Type-42 Directed Energy Support Weapon
- Type-52 Directed Energy Support Weapon
- Zeus 320mm plasma cannon
- Type-1 Energy Sword
- Type-25 Plasma Pistol
- Type-25 Plasma Rifle
- Type-25 Brute Plasma Rifle
- Type-51 Plasma Repeater
- Type-52 Plasma Launcher
- Type-55 Storm Rifle
Frank O'Connor, Bungie's former head of public relations, stated in 2006 that the plasma used by the Covenant is not plasma as current science knows it, but something "far more dangerous, arcane, and destructive." This claim has not been elaborated on in later sources and some actually indicate otherwise, with Halo 4: The Essential Visual Guide specifically making a note that the Covenant used conventional plasma in imitation of Forerunner particle weaponry.
- ^ There is a difference between baseline titanium and Titanium-A, an augmented form of titanium, used in UNSC starship armor. This along with the fact that Titanium-A armor is sometimes layered with tungsten (which has a melting point of 3,422 °C) means that the melting point of their starship armor is higher than that of conventional titanium.