Differences in damage between incendiary, laser, and plasma.

[mumble]

I've often thought about the differences here, all 3 use heat based damage in  a sense, but are treated differently, and I started to think why, and I think I might have an idea on why they perform different despite all being thermal based. This bothered me for a while, as how could these mechanically damage differently if they were JUST thermal energy? So I decided to brainstorm a little.

Incendiary is incredibly indirect, its a large amount of thermal energy without any real specific precision, and damage typically comes from large scale burns rather than incredibly powerful, directed burns, this means its generally unlikely to hurt any TRULY hard targets, but the large encompassing thermal energy could potentially flood any opening points inside the enemy, which explains why say, a cyber-disk might be effected by fire, as the flames and fuel might leak inside, and ignite the internals. Typically its a large, and sloppy ignition of fuel like gasoline or other incendiaries, which burns "hot" but not hot enough to melt anything substantial (usually) while also getting everywhere. However, besides pure thermal energy, there is nothing else to it for the most part.

Lasers are a velocity lacking direct beam of light energy : using a massively powerful beam of light which can burn / melt through many materials, and do more / less damage depending on the width of the beam, the power of the beam, and how heat resistant the material fired at is. However, despite the power, the beams have 0 kenetic energy, so armor which is stunningly heat resistant but fragile would still be viable, while armor with a high tensile strength and flexibility would be less viable if it cannot tolerate and dissipate heat. Besides that theres a possible issue of radiation : much like how sunlight can erode things that heat alone would not damage, there is a good chance of severe radiation particles which could damage tissue, fry electronics, or even cause metal to corrode / spark (like putting a spoon in the microwave) so even if something was entirely thermal resistant, the radiation. As a realworld example, light from welding is incredibly corrosive, and even if the light does not heat things up, having clothing exposed to this light for a significant amount of the time will severely damage it : so hypothetically one could even have a "heatless" laser which was room temperature, but fired intense radiation.

Plasma is like a marriage of kinetic weapons like bullets and thermal energy, firing out accelerated particles with excessive heat also involved. Because of the merge, its typically more effective than laser in most situations as it takes the heat, and mixes with particles, so the light, but heat resistant armor mentioned before would not be viable as the particles could still penetrate them with the high velocity. Theres also the issue of the anti gravity field which I assume could have effects on physics which bring in unforeseen issues with armor. However, the heat is less direct and splashes off of the particles more than the laser weapon as impact causes a dissipation of heat away from the impact site more than a laser would, meaning potentially armors resistant to ballistics but weak to lasers might face issues from plasma, unless heat itself would change how the material handles the impact, or the impact handles how the material handles the heat.  Theres also a possibility that the intense speed, and single particle could cause an effect like in the LHC does, where particles impacting creates new particles (like the higs boson) which could wreck havoc which cannot yet be studies well by xcom, be it chemical changes in the target, corrosion, or even reforming the chemical composition of matter in ways which xcom might not entirely grasp yet.

Not sure if anyone cares about this, but it feels better to at least have a head-canon for why some things are better with lasers, others with plasma, and I wonder if maybe this makes sense with lore, or if I completely missed something on this : as far as I can tell this makes sense, though plasma weapons don't have much information on them that I'm aware.

[The Reaver of Darkness]

Military-grade incendiary would probably use thermite or something else that burns extremely hot, like magnesium or white phosphorus. The incendiary flames would burn at a few thousand degrees and would melt many kinds of metals. They would ignite nearby objects but the flames that spread would be far cooler. A sectopod would be susceptible to these flames (and indeed they are) because it is made of metal. While the flames cannot melt alien alloys, the metal exterior will transfer heat rapidly throughout the sectopod, which is very bad for its internals. A cyberdisc would be particularly vulnerable to incendiary because it is so flat, meaning it can change temperature very rapidly. A reaper might have flammable fur, but these flames are so hot the fur will be singed off instantly, and it's the animal's fat that would burn. A reaper might be weak to incendiary, but mostly because it's big and wears metal.

The UFOPedia articles describe plasma as accelerating particles from within an anti-gravity field. They use their anti-gravity tech (fueled by Elerium) to generate a plasma perhaps by forcing the matter out of the weapon with so much energy it just heats up to several thousand degrees. I imagine they use containment fields generated by the Elerium to prevent the plasma from expanding while it is a projectile traveling through the air. When it hits, it would deliver such a large amount of heat energy that it would vaporize a chunk of the target, melt a lot more, and cause an explosion from expanding hot material. This weapon would be most effective against materials with low melting points, being able to destroy large chunks of wood or living tissue, but even sturdy armor could be torn apart by enough plasma hits.

I imagine they use similar technology to generate fusion--the containment field is used to heat a ball of material to several million degrees which causes it to fuse and release far more energy than was put in. It's the same tech, only requires a larger energy input and isn't efficient in small arms.

Lasers would differ from plasma in how they interact with a material, as you said plasma makes direct hot material contact while laser is making light contact. Sectopods are plasma-shielded, probably their thick alloy armor absorbs the heat rapidly and dissipates it across the body rather than melt. That's why a very powerful plasma shot can damage them just fine, but normal plasma they're virtually impervious to. I can't imagine why lasers would work well against them, they look reflective. But if the lasers operate across a wide range of frequencies through infrared, visible light, and some ultraviolet (which you'd expect, based on the yellow-white beam), then the beam will interact with almost any material, with a portion of the beam being reflected off, a portion being absorbed, and a portion traveling through uninhibited or will be refracted. That which goes through one layer on a complex target such as a soldier wearing armor or a sectopod will get reflected or absorbed by the next layer. So perhaps the sectopod's armor is semi-transparent to a frequency that its internals are particularly susceptible to.

[RSSwizard]

Incendiary: As reaver said, it heats up the external surface of an object and even if it cant damage the surface it will transfer heat and damage stuff inside. The armor on the cyberdisk isnt that strong anyway so the thin outer shell heats up rapidly then anything sensitive inside gets fried.

Laser: Okay so you have a beam of light that is heating up a microscopic area on the surface of the target object. For the brief fraction of a second it strikes (we're talking like 1/100 sec here) that pinpoint area is being heated up to like 100,000 degrees or higher, causing that little area to vaporize and then transfer its heat to the surrounding tissue or metal. Which also allows the laser to continue penetrating into the target. The amount of firepower is more a product of how long the laser beam is turned on.

The kinds of wounds this causes are sorta explosive, as if micro-explosives had been embedded in the target and popped, leaving a big bloody and smoldering hole (now you know why the laser rifle does 60 damage). The deeper it shoots into the target the Bigger the Entrance Wound is going to be to the point of just blowing the target to pieces and leaving a pile of charred remains.

Likewise even alien alloys aren't going to be safe from this, but the sectopod has enough armor that its only going to heat up a small patch of it and do the equivalent of putting a ding or small crater in it (the armor will most certainly be scratched). The reason a followup shot will not continue to dig is just because it's unlikely to hit the same spot twice (even though the laser has no recoil, targets move around and so does a soldier's aim).

The laser cannon on the tank has enough firepower to blow a hole in it reliably though, while the heavy laser or laser rifle has to hit an area that has a thinner overlapping plate or exposed machinery (thus "rolled high on the damage roll").

contrary to popular belief: A Mirrored suit of armor is absolutely useless against lasers. If even a small amount of the energy is absorbed it will deform the mirrored surface, damaging its reflectivity, then its like anything else. It might reduce damage a little bit (like 10%) but its not worth the gleam of making yourself a huge uncamouflaged target. If however your armor was covered in refractive Crystals (like diamonds) specifically angled to redirect or scatter light ("glittering") that might provide a significant reduction in effectiveness, still thats like a 50/50 hit or miss whether it provides any effectiveness (the crystals would have to be hit)

(im not sure about this, but I remember distinctively that a single shot from ANY laser would kill a Sectopod where it stood?)


Plasma: Regardless of description the plasma weapons are presented graphically and otherwise as a Projectile that travels downrange like many plasma weapons from sci-fi tv shows (such as the staff weapons from stargate). The ship weapons are presented as a beam but their construction also looks quite abit different than the ground weapons.

The plasma is contained in some kind of field, both compressed and superheated. On impact the containment is breached (like a glass ornament), and then plasma does what it does - expand violently and quickly and impart its heat on everything it touches.

While you might think that a bunch of gas at 500,000 degrees is just going to vaporize and set things on fire remember its got Pressure behind it too, because its compressed. Its not just simply colliding with what it hits.

TL;DR with plasma you're talking about being hit by a Shaped Charge pretty much, except the damage is rather topical instead of focused in a penetrating point. The real damage from a plasma weapon is the localized Explosion that takes place which is directed into the target by the projectile's momentum. But the blast radius of the explosion is going to be extremely limited because as soon as it imparts that heat into something, like vaporizing flesh and bone, it literally loses steam.

(chemical explosives derive the majority of their damage from the release of Supercompressed gas, the temperature of an explosion might reach over 5000 degrees but the thermal effect is miniscule compared to the crushing strength of the blast wave)


The kind of wounds this would cause are similar to what lasers do except it doesn't matter whether the target is biological/flexible or a hard-shelled target. Its going to blast a big hole in it either way and its going to slam with explosive force immediately since the high temperatures are already there (the object doesn't need to be heated up in order to be subjected to this brute force).

Shoot a wall with a laser and itll blow a small hole in it and set it on fire. Shoot a wall with a plasma gun and it'll blow a hole in it big enough to walk through, and even if its a weaker plasma weapon it would probably still blow a hole in it because of the concussive effect involved (blunt force is the best way to break scenery IRL).
 

[yrizoud]

IMO you're overthinking this. UFO's "lasers" behave like projectiles travelling 10000000 times slower than light, are visible in broad dailight, and produce a pew pew sound. The name "laser" is only used because it's similar to old sci-fi concept for futuristic weapons, and trying to reconcile it with actual lasers does not seem to bring anything interesting or logical.

[ohartenstein23]

Plasma has the additional fun of being a superheated ionized gas, so once the containment breaks and it is released upon the target, the ions of the gas strip electrons from the target to help make up the difference, causing a whole world of chemical reaction fun!