A particle-beam weapon uses a high-energy beam of atomic or subatomic particles to damage the target by disrupting its atomic and/or molecular structure. A particle-beam weapon is a type of directed-energy weapon, which directs energy in a particular and focused direction using particles with negligible mass. Some particle-beam weapons are real and have potential practical applications, e.g. as an anti-ballistic missile defense system for the United States and its Strategic Defense Initiative. The vast majority, however, are science fiction and are among the most common weapon types of the genre. They have been known by a myriad of names: phasers, particle accelerator guns, ion cannons, proton beams, lightning rays, ray guns etc.
The concept of particle-beam weapons comes from sound scientific principles and experiments currently underway around the world. One effective process to cause damage to or destroy a target is to simply overheat it until it is no longer operational.