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 Psienesis wrote:

 Co'tor Shas wrote:
Well, lighting is hotter than the surface of the sun (IIRC), but it is there for such a small amount of time it has no affect out of where it hit.

It is, but a plasma weapon is (compared to a lightning bolt) around for much longer (especially over comparative distances). The ball of plasma exists for a not-inconsiderable span of a few seconds... that's enough time for it to transmit a goodly portion of its 20+ million degree temperature into the surrounding air, which then transmits that into anything in its airspace. Even if it was only 1% of its heat, that's still 200,000 degrees. That's fething hot.

I doubt it would burn things for kilometers. Air is very cool and there is a lot of it. But you sure as gak would need heat protection if you're the poor sap firing it.

I guess the question is of how fast it flies. If it is very fast (not the slow-moving ball they like to show us), than the guy firing it should have relatively little to worry about, as long as the gun is properly heat-sheilded, and doesn't overhea-

Oh.
Welp.

It's also worth remembering that being removed as a casualty in a game of 40K doesn't necessarily equal DEAD.

The TT game doesn't cover things like broken arms, bad burns, etc. You could have a guy who is badly scalded and retreats for medical aid, or someone who gets a faceful of hot gases and needs bionic eyes. Then, given that these weapons are way more valuable than many users of them, you could also have the guy who sees that the weapon is malfunctioning and runs off the battlefield to preserve the weapon which is more expensive than he is.

I mean, when guys get shot in 40K, they never slowly bleed out, or get clipped in the leg. They die, or they are fine. The novels are full of injured guys staying behind to hold off the enemy, and that never happens on the TT either, but it doesn't seem to bother people nearly as much as a plasma gun overheat, even though the first is something that actually happens right now in the real world, and nobody has seen a plasma gun overheat, ever.

We've also never seen a plasma gun. At all. Ever.

Just finished reading Faith & Fire, a Sororitas novel. It includes a plasma pistol exploding like a small grenade.

Just the way I like it

Yeah, I always imagined it just vented excess heat or something to prevent the gun from overheating, and at least in a guardsman's case, its just a matter of whether or not the vents are pointing at his face when it happens.

On the new commisar isnt it heavily implied his gun exploded in his hand?

GreaterGoodIreland wrote:Just finished reading Faith & Fire, a Sororitas novel. It includes a plasma pistol exploding like a small grenade.

Just the way I like it

To be fair, that was when it was tossed into a psychic storm complete with flaring warp lightning.

The silly thing is that the reason it overheated was because it was fired continuously for about a minute at the same guy it killed by exploding next to his head...

I don't remember if it was in a codex or the 3rd Edition BRB but it was in that section of time, I remember reading that to reload a plasma gun, two canisters of very volatile elements have to unscrewed and replaced. Plasma pistols only have one visible so take that how you like. Anyway, if inserted improperly the cores go unstable or leak, hence 'Gets Hot'. Its easy to say the leak occurs over time until it actual does the leaking out, thus a saved wound instead of instant plasma explosion that kills the user.

I imagine that in normal operation the weapon either vents (which can kill) or a safety mechanism kicks in and it refuses to fire (which doesn't) - but there is also the potential for failure of a component, particularly if it was produced by a FW or manufacturer who isn't that great at working with high-tech, or it has been damaged during fighting, at which point it goes off like a plasma grenade. These three options would be covered by the "To Hit" and armour save rolls.

Also, with regards to similarity to lightning, Ball Lightning last a long time but doesn't burn off our atmosphere.

I also think I once saw a guardsman miniature on the internet, where he is getting melted by plasmagun misfire. Anyone?

Ball lightning is weird.

Uyzy wrote:

I also think I once saw a guardsman miniature on the internet, where he is getting melted by plasmagun misfire. Anyone?

is this an offical gw miniature or conversion? I swear I saw the exact same one in a smurf army in wd december 2013

Its a cute thing everyone with SM eventually makes


Edit: Yes its a conversion with a Rocket hand and extended flag carrying arm. as below

 Da krimson barun wrote:

is this an offical gw miniature or conversion? I swear I saw the exact same one in a smurf army in wd december 2013

I think it's a normal marine with a hand, which is normally used to support rocket launcher marine from tacticals

As others have mentioned, I think there's a wide range of situations that can occur with Imperial plasma weaponry.

The technologies for plasma engines, plasma drives, power plants, etc. seem to be fairly safe (provided no-one clamps a meltabomb to the side of the reactor, or stabs your Techpriest in the back) in the 40k universe so we have to assume either:

1 - miniaturized (vehicle-sized and smaller) plasma technology is either inherently more dangerous,
2 - the technology to properly manufacture 100% safe plasma weapons has been lost,
3 - the particular plasma weapons themselves are simply so ancient that they are beginning to fail.

It's pretty reasonable to believe that miniaturized plasma devices would be less stable, more prone to mechanical failure, and thus more dangerous. Large plasma reactors probably have very significant monitoring systems, cooling systems, and redundant failsafe procedures to prevent any kind of meltdown or explosion. It's probably very similar to how modern nuclear power plants are operated today. The same goes for plasma engines on starships or any kind of strategic-scale plasma weaponry; even though they produce much more power (and are therefore much more 'dangerous') they don't require portability and so can rely on heavy-duty, stationary safety features. Vehicle-borne or man-portable weapons, however, must sacrifice a great deal of weight and size to be usable on a battlefield, which almost always creates a greater degree of risk of component failure. Think about a desktop computer vs. a smartphone. With a good water-cooling system and high-speed fans, you could probably run a desktop in the middle of Death Valley (if you had power, of course). A smartphone, however, might shut down after 10 minutes in direct sunlight.

Some canon theorizes that since the Dark Age of Technology, the ability to manufacture 'proper' plasma technology has been lost completely. This being said, Forgeworlds are still able to manufacture close facsimiles of (what we can assume was) the STC variants of plasma guns, cannons, etc. using 'modern' technology adaptions. Unfortunately, these weapons pale in comparison to their ancestors and, as such, are prone to overheating, failing, or exploding (depending on what is necessary for the plot). Perhaps they have fragmentary schematics, have just tried to reverse-engineer ancient plasma relics (though it's unlikely they would be able to take them apart, given their 'holy' status), or maybe the materials are just too rare and expensive to keep up with the mass-production necessary to fuel the Imperial machine. Regardless of the reason, it may simply be that 'modern' plasma weapons are cheap knock-off versions that don't have the same quality as the plasma weapons from yesteryear.

Lastly (and least likely, in my opinion), it could be that the ability to manufacture miniaturized plasma weapons is lost completely. 40k canon often likes to talk about "jealously guarded relics" and "priceless artifacts" when referring to particularly fancy versions of weapons, so it's possible that every plasma weapon in service is theoretically one that was originally manufactured during the Dark Age of Tech, and has survived for thousands of years. If so, then either Imperial miniaturized plasma technology was always inherently dangerous—having nothing to do with modern copies—or the weapons that are still in service are getting towards the end of their operational lifespan and, despite the tender loving care of the Munitorium and Mechanicum, starting to fail. I find this version to be least likely because 1) even though plasma weapons are rare, there seem to be far more than would have survived for 10,000-20,000 years, 2) genuine relics of the Dark Age (owned by Space Marine Chapter Masters, Battlefleet Generals, etc.) tend to be described as much more reliable, and 3) the Mechanicum seems to have far more reliable plasma technology amongst its troops which, while not impossible to be all relics, seems a bit far fetched.

As for the effects, I agree with whoever mentioned the Halo plasma rifles. Overheating and failing (such that you burn out a coil, or a control mechanism) is probably the most likely situation. The next step up would probably be an emergency venting process that could potentially burn or scald the user. The worst case scenario would be the most dramatic and memorable, wherein the weapon explodes, or melts, or misfires and the bolt is lodged in the chamber. Logically this would be something that no armour could ever protect you from (we could assume the explosion would be at the same intensity of the firing profile) and a rare, though catastrophic, occurrence. The fact that people often don't realize that a Gets Hot! wound doesn't have an AP value in-game (at least in the 40k ruleset), probably leads me to believe that many people have the impression that the weapon explodes 1/6 of the time, which is probably fairly unlikely.

DoW

In case anyone was still interested in the thermodynamics of this, I belive what you are looking for is the energy transfer equation. (sorry it wont let me type superscript/subscript)

Q = m c t

where

Q = quantity of energy transferred (kJ, Btu)

m = mass of substance (kg, lb)

c = specific heat of the substance (kJ/kgoC, kJ/kgoK, Btu/lb oF)

t = temperature difference (rise or fall) in the substance (oC, K, oF)

So the key to this is that the specific heat of the substance (plasma) is super wicked hot

making the temp diff really significant

The saving quaility here is the mass of the substance (if it were subatomic then you would be kosher, if it were like golfball sized...well then yeah you are gunna have problems)

As long as the projectile that is leaving the containment feild (however they say they worked out containing raw plasma, or really didnt since they dont work all the time) is sufficently small you wont do things like ignite the atmosphere, and as long as it moved quick enough, it wouldnt cool down enough to lose effectivness at range.

(please correct me if i am wrong, it has been years since i have been in thermo)

The images of plasma we're given show something that ranges from tennis-ball size to roughly the size of a basketball, and travels slow enough to actually visually track it from point A to B.

We don't know how much of that "ball" is the actual plasma "bolt" and how much is the surrounding air suffering the effects of that minuscule point of intensely hot plasma. The slow-moving is a problem, as is the Space Marine game's depiction of a "charge shot" sticking to the target briefly before exploding.

One thing that puzzles me about Imperial plasma weapons is the blue glow of the coils. Why are they glowing blue? Surely any plasma would be generated in the firing process, not contained within the weapon.

It's the weapon overheating. The coils are glowing because they are getting hot.

Things don't glow blue (well, they do, but not like that) when they get hot. Those coils are made to look like a transparent flask filled with Star Trek warp core-stuff, otherwise known as "generic sci-fi functionless glowing". They're also blue even when the weapon has not been fired.

Oh. Perhaps the coolant the Imperium uses glows? I don't know. I think it's silly myself and I prefer just painting the coils metal.

Because it looks cool. No other reason. It's kind of like Star Wars... good guys shoot blue, bad guys shoot red. Space Marines shoot blue, Necrons shoot green. Chaos shoots red. Tau shoot white-blue. Eldar shoot white. Dark Eldar shoot purple.

 TheCustomLime wrote:
Oh. Perhaps the coolant the Imperium uses glows? I don't know. I think it's silly myself and I prefer just painting the coils metal.

Same! I like to think of the coils as part of the magnetic propulsion of the weapon rather than coolant.

Stupid rule anyway, who would use a gun that has a 17% chance of misfiring every time it is fired? Maybe the Imperium wouldn't care about Guardsmen but makes no sense to select, train, genetically modify, provide years of combat experience, give a holy relic suit of armour to a Space Marine and then arm him with such an unreliable weapon.

Because it's the only weapon they have for a specific kind of target.

What I never get is why on earth would you equip masses of troops with a gun that will kill them with 1 out of 6 shots it takes? That's just moronic! And a gun that can get to critical heat levels in just 1 shot? Seriously?
Never have I seen in books a plasma gun kill its bearer with the first shot it takes.


Automatically Appended Next Post:

 tyrannosaurus wrote:
Stupid rule anyway, who would use a gun that has a 17% chance of misfiring every time it is fired? Maybe the Imperium wouldn't care about Guardsmen but makes no sense to select, train, genetically modify, provide years of combat experience, give a holy relic suit of armour to a Space Marine and then arm him with such an unreliable weapon.

Oops - I shoulda read to the end.

Perhaps the damage out put was worth the danger

or back in da DAoT it used to be muuuuch more stable.

It was a much more stable technology in the past. This is noted as one of the reasons that the planet Ryza is so important, it is the last bastion of plasmatech comprehension (such as it is) in the Imperium.

For a start though it means 'veterans' can not possibly have a lot of experience with plasma weaponary - unless they are as lucky as a lottery winner.
Secondly, if you knew a gun had an incredibly high chance of killing you if you fired it - you would be more scared of it than you would the opponent, that's no fit state of mind to go into battle with!