Yes, there could be. Its efficiency and complicated nature would make it highly ineffective as a combat weapon though.
The ray gun is by far the best.
There are some different applications for plasma torches (or plasma arc or plasma gun) including plasma cutting, plasma spraying and plasma and waste disposal.
It is the super heated ionized gas. Also halo uses them.
Scare Tactics - 2003 Plasma Gun was released on: USA: 5 March 2003
PLASMA Burst
plasma rife or a fuel rod
Plasma Pistol, as it is in about all Halo games.
Not yet, although it may at some time in the future.
halo combat evolved: m6d pistol , ma5b assault rifle , m9 he-dp grenade , m90 shotgun , s2 am sniper rifle , m19 ssm rocket launcher, m41 laag , plasma rifle , plasma pistol , needler , plasma grenade. halo 2: smg , battle rifle , particle beam rifle , brute shot , carbine , energy sword , machine gun turret , magnum , needler , plasma rifle , rocket launcher , shot gun , sniper rifle. halo 3: assault rifle , battle rifle , beam rifle , brute shot , carbine , energy sword , flamethrower , fuel rod gun , gravity hammer , machine gun turret , magnum , mauler , missile pod , needler , plasma pistol , plasma rifle , plasma turret , rocket launcher , sentinel beam , shotgun , SMG , sniper rifle , spartan laser , spiker. halo reach: assault rifle , DMR , grenade launcher , magnum , rocket launcher , shotgun , sniper rifle , spartan laser , concussion rifle , fuel rod gun , focus rifle , needler , needle rifle , plasma launcher , plasma pistol , plasma repeater , plasma rifle , energy sword , gravity hammer , plasma cannon , machine gun.
HUMAN: Assault Rifle. Magnum. DMR. Sniper Rifle. Rocket Launcher. Shotgun. Target Locator. Grenade Launcher. Spartan Laser. Detachable Machine Gun Turret. Frag Grenade. COVENANT: Energy Sword. Gravity Hammer. Plasma Pistol. Plasma Rifle. Plasma Launcher. Plasma Repeater. Fuel Rod Gun. Needler. Spike Rifle. Needle Rifle. Concussion Rifle. Focus Rifle. Detachable Plasma Turret. Plasma Grenade.
You place a protonic commuty bolt, Inside the capture chamber of a R368.
Not by any "guns" we have at present; and if "fired" through a standard gun - would either be too weak to do any harm to the target - OR - would melt the gun first.