Phasers

The phaser is the standard Federation beam weapon system. This type of weapon came into common use c.2255, replacing the laser weapons then in service. Phaser is an acronym for PHASed Energy Rectification, a term which referred to the original process by which stored or supplied energy was converted to another form for release toward the target without any need for an intermediate energy transformation.

Although this term is something of a holdover, it remains true in modern phaser systems. Phaser energy is released by the rapid nadion effect. Rapid nadions are short-lived subatomic particles which can liberate and transfer strong nuclear forces within a class of crystals called fushigi-no-umi.
Type 10 Phasers: As of 2364 this was the heaviest weapon in use aboard Federation vessels, comprising the main armament of the Galaxy class starship
Type 12 Phasers: The main phaser armament of the new Sovereign class starship comprises Type 12 phaser arrays. These are the most powerful phaser weapons currently in use by the Federation.