Plasma weapons come from a number of sources, most significantly the Traveller universe, where they are used very prevalently. Plasma-like weapons also appear in a number of on-screen science fiction sources, such as Star Wars, Babylon 5, and Stargate SG-1.
Plasma weapons use hydrogen fuel, either from a source tank or injected as self-contained pellets, heated near-instantaneously to a plasma state by lasers within a magnetic bottle inside the weapon. The magnetic bottle then collapses and compresses the plasma into a thin stream which is simultaneously ejected from the nozzle of the gun via magnetic funnel. The plasma stream reaches temperatures in excess of 10,000 degrees C and is ejected at speeds of up to 8000 meters per second from the nozzle. In a standard, earth-like atmosphere, the weapon has an effective range of up to several thousand meters. The extreme temperature of its plasma bolt combined with the physical force of the stream’s impact make these truly formidable and terrifying weapons.
Plasma weapons are made all the more horrific by their "splash" effect. The plasma stream hitting a target, though it looks much like an energy beam, is actually a very physical object. If the leading edge of the stream doesn’t penetrate all the way through a target, a good portion of its mass bounces back, interfering with the rest of the incoming stream’s coherence and "splashing" the remaining plasma over a large portion of the target’s surface.
This splash effect makes these weapons very dangerous to use at close quarters, as a plasma "splash back" can kill the operator just as surely as the target. An operator would do well to make sure he has at least several meters (hopefully much more) of clearance between himself and the target.
Obviously, the weapon needs a powerful energy source for even a single shot, making a compact enough battery or generator potent enough to power the weapon through multiple shots problematic. Ideally, the power source should be integrated into a modular hydrogen fuel source to simplify reloading. Good candidate technology for this includes advanced conventional batteries (probably carried in backpack form), monopolar generators, chemical explosive power generators (particularly a good choice, as these one-use devices could be integrated along with the hydrogen fuel into a plasma-weapon "bullet", which in turn can be integrated into magazines,) superconductor loops and crystals, and for very advanced models, SF exotica such as antimatter.
Because of the extreme temperatures reached both within the weapon’s magnetic bottle ignition chamber and in the barrel directing the plasma stream, an efficient cooling system for this weapon is a must. Coolant may be supplied in tandem with the hydrogen fuel for the system, the freon (or whatever) being pumped throughout the ignition chamber and barrel system simultaneously with the hydrogen fuel being pumped into the ignition chamber, then vented after the plasma stream is fired. Even with an active cooling system, however, the chances are this weapon is going to become very hot after only a few shots and would probably require special protection in the form of insulated armor for the operator.
These weapons would have a hideous recoil for their size. A plasma gun the size of a medium pistol would kick like a conventional 10 gauge shotgun. Recoil compensation of some sort, either internal to the weapon and/or an external stabilizer, would have to be integrated into the weapon.
Plasma guns would also have a very pronounced firing signature. The plasma stream breaking the sound barrier, the crack of waste gasses escaping, the bright light and IR signature, and the puff of a small cloud of venting coolant all add to this.
Needless to say, these are very powerful and devastating firearms. A typical plasma rifle from the Traveller RPG universe could readily take out a modern-day tank with a single shot. They are so lethal in that universe, in fact, that the use of exoskeletal powered armor by infantry is commonplace just to give the average soldier a fighting chance.
An offshoot of the standard plasma gun, the plasma projector expels its super-heated plasma as a wide-angled jet as opposed to a tightly-compressed stream. While it has a much more limited effective range (up to a hundred or so meters) than its cousin, it wide area-effect makes it ideal for in-close combat, such as those found in urban or enclosed environments.
It also lacks the high penetration of a compressed-stream plasma gun, in effect making it very similar in effect to a flame-thrower, with the exception that the plasma projector’s "flame" is much hotter (in excess of 10,000 degrees C), can extend dozens of meters further, and is much more easily controlled. Another way to think of the weapon is a jet’s afterburner reduced to rifle form.
Tech Level: 17
|A stormtrooper from the Star Wars universe fires a plasma bolt from his blaster rifle. Image (c) Lucasfilm|
Blasters and similar weapons are very familiar to every science fiction fan. Their bright, slower-than-a-bullet bolts mark them as a type of plasma weapon, though of considerably less lethality than Traveller-type plasma guns. Their plasma streams seem to be cooler (on the order of a "mere" 1000 degrees or so) and travel at subsonic speeds, delivering far less physical impact. Whereas Traveller plasma rifles are instantly lethal to anyone not wearing special armor, it is possible for an unprotected person to survive a blaster shot if it hits a non-lethal area on the body.
Getting the plasma stream to be just hot and forceful enough to be as lethal as a modern firearm without being overwhelmingly devastating requires a great deal of finesse and control over the very chaotic dynamics of the plasma, hence its higher tech level than a ‘standard’ plasma gun.
The reason for creating a less powerful version may be multi-fold. Blasters would use less energy and require far less coolant than their plasma gun cousins, making them less expensive to manufacture and operate. Plasma guns would also create quite a bit of collateral damage, so blasters may be preferred in a number of situations, especially on board spaceships and space stations where collateral damage could have truly catastrophic effects. Also, blasters may in some universes simply be the "civilian" versions of the more powerful military plasma guns, letting the civilian population take advantage of plasma gun technology but without it posing a serious challenge to military firepower.
Also from the Traveller universe, fusion guns are super-advanced version of the plasma gun, which holds the plasma in the gun just long enough for a fusion reaction to take place among the hydrogen nuclei. Temperatures of these plasma streams would easily reach 200,000+ degrees C.
Of course, the energy, pressure, and coolant requirements for such a weapon would be much higher than for other plasma weapons and blasters, but they are much more devastatingly powerful. Every conventional material known would instantly vaporize at contact with the fusion-hot stream; giving the gun not only hideously high penetration but also a much more damaging and far-reaching ‘splash-back’ effect. Its not inconceivable that a fusion gun firearm could sink a modern-day aircraft carrier with just a few well-placed shots.
In the Media:
Star Wars, et al
Babylon 5, et al
Stargate SG-1, et al
Traveller RPG, et al
Fire, Fusion and Steel: The Traveller Technical Architecture
On The Web:
A plasma gun from the jihad universe: