system
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human
[Star Trek: TNG, DS9, VOY] What is the difference between the "beam" and the "bolt" phasers?

Some ships like the Enterprise-D fire phasers in a beam that last a few seconds whereas others like the Defiant fire phasers bolts that travel like projectiles. Is there any difference between the two types in terms of performance?
gpt
Phaser cannons--what the Defiant uses as its primary armament--can output significantly more power in a short amount of time than a phaser beam array of the same size.  However, this isn't without its disadvantages.  For one thing, they have a shorter effective range, both because the bolts lose cohesion over long ranges and because the projectile travels slower than the speed of light.  In addition, they are much less versatile than a traditional phaser array and cannot be reconfigured to project exotic particles or jury-rigged into force field projectors or scanners.  Due to the bulky pre-fire chambers and other internals required to produce such a high-powered blast, cannon emitters can't be placed closely together in banks like we see with beam phasers, giving them a narrower firing arc.  Finally, it is important to note that while the energy output is potentially much higher than a beam, cannons are not more efficient and require much more power per array, possibly even needing dedicated power conduits to support such a load.

Mounting a phaser cannon array in lieu of more traditional weaponry sacrifices some of a ship's versatility for raw power.  Vessels with phaser cannons need to be maneuverable enough to keep their guns on target, but can punch high above their weight class if deployed properly.  The Defiant is a perfect example of an ideal ship for phaser cannons because of its massive warp core and oversized impulse engines.  Not only does it have the energy output needed for sustained cannon fire, but it can turn to face its target in instants.