Interesting Plasma Weapon Concept

[Starglider]

That'll just blow the loop into charged fragments with the explosive force of the initiator charge.

No, the energy is stored in the magnetic field created by the moving current, not electrostatically. Disrupting the conductive path will release the energy at heat, this is why superconductor quenches are so dangerous (or at the very least, expensive in terms of liquid helium loss) in applications such as particle accelerators.

To dissipate loop power explosively, you need to fault the circuit, either by shorting it

It's a SUPERCONDUCTING LOOP. It's already as 'shorted' as it can possibly get.

The arcs generated will hopefully break down insulating material enough fast enough to do damage.

There won't be any direct arcs because there is no potential difference outside the loop. There may be some minor arcing generated by eddy currents as the field collapses.

or overloading it.

Which will cause the superconductor to exceed critical temperature or field density and stop superconducting, causing massive heating and an explosion, yes this is why you leave a margin of safety when you charge the shell prior to firing.

[metavac]

No, the energy is stored in the magnetic field created by the moving current, not electrostatically.

That's besides the point. Assuming we're still talking about a room temp superconductor, blowing the coil into fragments will only alter the current path into smaller elements. The magnetic field geometry changes drastically, but it still persists.

Disrupting the conductive path will release the energy at heat, this is why superconductor quenches are so dangerous (or at the very least, expensive in terms of liquid helium loss) in applications such as particle accelerators.

Quenches are dangerous because they propagate, and that's because some of the material has returned to a normal but still conductive state. It can discharge into the remaining material and further raise current and temperature beyond their critical points. For a room-temp superconductor, you can't do that if you've just blown the circuit open.

It's a SUPERCONDUCTING LOOP. It's already as 'shorted' as it can possibly get.

That's where quenching comes in.

Which will cause the superconductor to exceed critical temperature or field density and stop superconducting, causing massive heating and an explosion, yes this is why you leave a margin of safety when you charge the shell prior to firing.

Isn't that what we're trying to do?

[metavac]

On second thought, blowing the loop would raise the temp of the fragments, so I guess you could say that secondary effects would include quenching.

[Starglider]

That's besides the point. Assuming we're still talking about a room temp superconductor, blowing the coil into fragments will only alter the current path into smaller elements. The magnetic field geometry changes drastically, but it still persists.

I'm not a physicist, but I know enough about inductors to recognise this as nonsense. Even making the ridiculous assumption that the coil will persists as large wire fragments, the total inductance of those fragments is a minute fraction (somewhere around a trillionth) of the inductance of the original coil. Even assuming lossless transfer they cannot hold more than a minute fraction of the original energy, and the rest is going to get dumped. Specifically it is going to get dumped into massive arcs across the gaps as the coil begins to break up, followed by general inductive heating of the debris (which will flash into conductive plasma within microseconds) and probably some degree of linear acceleration of particle jets. In practice it will be even faster than this as the coil will get smashed into dust by the impact or explosion alone, before the heating starts.

Quenches are dangerous because they propagate

Whereas here we've smashed the entire superconductive path in one massive impact, how can you fail to see that this will force the energy to be dumped into stray currents and particle KE?

Which will cause the superconductor to exceed critical temperature or field density and stop superconducting, causing massive heating and an explosion, yes this is why you leave a margin of safety when you charge the shell prior to firing.

Isn't that what we're trying to do?

Only at the point of impact, we don't want it going off in the launcher due to overcharging the coil.

[Zixinus]

So it would blow up like a regular explosive, just with a bigger boom? Sorry for the retarded terminology, but I don't know much about it. Heck, I can only follow the discussion half-way trough.

My line of thought was that at high currents and high voltages, there is something called "arch flash", where essentially a miniaturized lighting forms, along with plasma that causes a violent explosion. Do I understand correctly that with a superconductor, that would happen?

Well, LOSAT was a bullet-guided projectile, though I don't know if the successor (CKEM) is. I still find that highly amusing...

Ermm, no. I'm talking rocket-bullets as bullets you use for infantry.
There are various advantages given, such as less recoil, higher reliability (assuming proper quality rocket-bullets), higher accuracy, higher range at the expense of low power at close range (due to the behaviour of the rocket) and high cost for a bullet (over a buck for one due to the higher standards for a rocket-bullet compared to a conventional bullet). Firing mechanisms would also be simpler too, you could use a battery and two electrodes to fire such a thing, as opposed to a "cocking" mechanism (or whatever they use). It would be fairly useless for general war use, but for specialized applications, like sniping or underwater or vacuum-rated use, it might work. They are also very cool.

[Starglider]

So it would blow up like a regular explosive, just with a bigger boom?

Pretty much. The exact effects on armour will differ from a simple HE shell, but frankly I doubt we can know precisely what would happen without building one and trying it. There still isn't a good predictive model of relativistic impacts, which is a rather simpler problem.

Do I understand correctly that with a superconductor, that would happen?

One way or another the vast majority of the stored energy is getting dumped into heat and fragment/jet KE within microseconds, which means an explosion, plus a hefty electromagnetic pulse.

[Winter]

Welcome to the forum.

Thanks.

First off, why are the aliens invading/attacking? The reason may define their weaponry very well. Also, can you explain the alien's attitude towards battle in general?

They're not invading in the classical sense. The initial attacks are meant to gather lots of samples of human tissue and DNA, so that the XVI organism (a virus-like parasite living in the aliens' bloodstream, possessing a distributed intelligence) which psionically controls the aliens can re-engineer itself to infect and control humans. To that end, the initial weapons are mostly taken from previously conquered civilisations. In our premise humanity is the last independent, intelligent race in the galaxy -- the rest of the galaxy has been pretty much raped and left for dead by the ever-expanding alien collective.

Also, robots can be great shock-troops. No sense in wasting powerfully augmented warriors to battle enemies, when a hoard of mass-produced automatons can weaken potential enemies.

We will be featuring robots extensively in the game.

To run it down, sending in warriors on foot, like in X-com, is only worthwhile if you want something from an area. In the case of a city, possible persons like important people or intellectuals, or materials and resources like fuels from an atomic plant. To cause damage in general, is not worth it.

We don't feature missions solely for destruction, except as retaliation and suppression against PHALANX, the player-controlled anti-alien organisation.

An attitude that you should keep in mind, is that any soldier or experienced warrior would rather choose simple and reliable weapons over complicated ones. That's why plasma weapons are worthless: they are overly complicated thus unreliable, ineffective compared to weapons like lasers or conventional firearms and just plain pointless. Beyond that, the more fire-power one has, the better.

I'm just working with the stuff I've been given. Considering the design of the plasma weapon models, I came up with the only plausible explanation I could think of. Particle beam weapons are the other family of alien weapons we've got in the game right now, and we're working on projectile-firing alien launchers and sniper rifles. We already have railguns and other plausible weapons technology in the game as well, with electrolasers on the books for the next version. There aren't many other radically different (and effective) weapons concepts that I can think of, but maybe people here can help.

For more hints, I recommend to study this site: http://www.projectrho.com/rocket/index.html

It's mainly focused on futuristic rockets, but stuff like aliens and side-arms.

Thanks, I'll give it a look when I get some time.

[rhoenix]

I'm just working with the stuff I've been given. Considering the design of the plasma weapon models, I came up with the only plausible explanation I could think of. Particle beam weapons are the other family of alien weapons we've got in the game right now, and we're working on projectile-firing alien launchers and sniper rifles. We already have railguns and other plausible weapons technology in the game as well, with electrolasers on the books for the next version. There aren't many other radically different (and effective) weapons concepts that I can think of, but maybe people here can help.

Given that I'm a fan of your project, I'll be watching avidly.

Quite honestly, you really could do worse than these forums for asking the futuristic weapons questions.

[metavac]

I'm not a physicist, but I know enough about inductors to recognise this as nonsense. Even making the ridiculous assumption that the coil will persists as large wire fragments, the total inductance of those fragments is a minute fraction (somewhere around a trillionth) of the inductance of the original coil.

I'm no physicist either, but it seems that if a superconducting coil fragments all of a sudden, current continues to flow in the individual fragments and each one is isomorphic to an semi-perfect LC circuit. I wouldn't think about trying to determine the total inductance of all the individual fragments and the system itself, but conservation of momentum requires the summed magnitudes of the induced fields to be equal to that of the coil.

The thing to remember is we're dealing with this miracle superconductor of yours. In that state there's no joule heating; there's no resistivity to drive it.

Even assuming lossless transfer they cannot hold more than a minute fraction of the original energy, and the rest is going to get dumped. Specifically it is going to get dumped into massive arcs across the gaps as the coil begins to break up, followed by general inductive heating of the debris (which will flash into conductive plasma within microseconds) and probably some degree of linear acceleration of particle jets. In practice it will be even faster than this as the coil will get smashed into dust by the impact or explosion alone, before the heating starts.

You're describing what happens during a quench of these supercooled superconductors, and that's only because there's current flowing through sections of the loop that have returned to normal conductive state and exhibit resistance. Those sections are dissipating power, heating as the electron drift velocity tends to zero, and thereby warming up adjacent section.

Whereas here we've smashed the entire superconductive path in one massive impact, how can you fail to see that this will force the energy to be dumped into stray currents and particle KE?

That's the thing. I do. I just don't see the current favoring a non-conductive path over flowing along another path within the superconductive fragment. We are talking about the conditions under which a superconductor might explode, right?

[Winston Blake]

The thing to remember is we're dealing with this miracle superconductor of yours. In that state there's no joule heating; there's no resistivity to drive it.

I don't know much about it, but surely even a room-temperature superconductor would have a critical temperature. Blasting the coil apart might be the wrong approach. Imploding the coil instead (with explosives wrapped around the outside) would force all the fragments together in a very hot fireball - then they would cease to be superconducting and the whole thing vapourises. Is that plausible?

[metavac]

I don't know much about it, but surely even a room-temperature superconductor would have a critical temperature. Blasting the coil apart might be the wrong approach. Imploding the coil instead (with explosives wrapped around the outside) would force all the fragments together in a very hot fireball - then they would cease to be superconducting and the whole thing vapourises. Is that plausible?

Hmm. Good point. In fact, you'd have to do that in one step to shape the explosion.

[Connor MacLeod]

Isn't dumping heat equivalent to a tonne or so of detonating TNT into an artillery shell going to create an explosion anyway? It'll vaporise the coil, and then you've just got a very hot expanding gas as you'd have when a HE shell goes off.

Yes, and no. In a conventional explosive (like HE) the fact that it does vaporize is part of its destructive elemnt, but time is as important if not more. A big reason conventional explosives are so nasty is because they generate massive, fast moving pressure waves - the explosive is vaporized very rapidly in a very small area (this is why explosives are measured in feet per second or detonation velocity.) Mike discussed this (and is referencing) stuff in his "Destruction" webpage mentioned some time ago and can be found here

But simply vaporizing the material won't be sufficient to create a "bomb like" effect (the TESB asteroid for example is certainly a kind of explosion, but I don't think its nearly fast enough to qualify as "bomb like") Same with your superconductor.

The only obvious difference to a HE shell I can see is that some fraction of the energy is going to be radiated as an electromagnetic pulse (which may cause a little eddy heating in conductive armour materials), but unfortunately I don't know how to calculate that (it will be a minority of the energy though).

LAst I checked, conventional explosives do not produce EMP, that's a province of non-nuclear EMP (specialized devicees) and nuclear detonations. (EMP is a very specific result created under atmospheric conditions.)

To make a shaped charge warhead I expect you'd explosively disrupt the superconducting loop with an initiator charge, and design the coil core to make your penetrating jet.

Its effect as a shaped charge will really depend on the velocity of whatever the "explosion" producees. Shaped charges tend to have high velocities IIRC 8-10 km/s, which is at or above the detonation velocity for many/most explosives, IIRC.

[Sea Skimmer]

LAst I checked, conventional explosives do not produce EMP, that's a province of non-nuclear EMP (specialized devicees) and nuclear detonations. (EMP is a very specific result created under atmospheric conditions.)

On a laboratory basis, EMP devices which employ conventional explosives do exist. They pretty much use the conventional explosive to move an armature extremely quickly, to get the ultra high wattage required to make a pulse.

[Connor MacLeod]

LAst I checked, conventional explosives do not produce EMP, that's a province of non-nuclear EMP (specialized devicees) and nuclear detonations. (EMP is a very specific result created under atmospheric conditions.)

On a laboratory basis, EMP devices which employ conventional explosives do exist. They pretty much use the conventional explosive to move an armature extremely quickly, to get the ultra high wattage required to make a pulse.

If I remember correctly, that's part of the "non nuclear" EMP category. it requires some elements in addition to conventional explosives for the EMP to be generated.

[Sea Skimmer]

If I remember correctly, that's part of the "non nuclear" EMP category. it requires some elements in addition to conventional explosives for the EMP to be generated.

Yeah you need a whole focusing assembly, because of the limited power involved for the resulting EMP to have any real effect you need to make it directional. This would be fine however, for a bomb or shell falling vertically on the target. When you said non nuclear EMP I assumed you meant all the various generator ideas which are out there, some of which have been tested, and which don’t employ any kind of explosives.

[Winter]

Alright, now that I'm finally in a position to do some more work on UFO:AI, I present you with a reworked concept. Please let us know if you think it's any improvement, and what's good/bad about it:

When the aliens need a sidearm, they don't screw around.

This plasma pistol is a nasty piece of work, Commander. Its operation is extremely complex and inventive, requiring a great deal of technical skill to create. The power pack alone is hundreds of years ahead of our technology. It stores enough power to heat several charges of hydrogen to a plasmatic state inside the miniature fusion chamber, which are expelled as plasma using the ionised particles' own velocity.

Unlike human firearms, the projectiles themselves are not stored in a magazine or reservoir. They are generated inside the pistol from hydrogen contained in the magazine, powered by the magazine's power-pack. Once the plasma is heated, it is fed into a spherical magnetic bottle created by a tiny generator device, a stack of which are stored inside each magazine. The whole mess -- generator included -- is then fired by a set of magnetic rails above and below the bottle.

The magnetic bottle contains and protects the plasma, keeping it from dispersing until it reaches the target. When a bolt reaches the target, the magnetic bottle keeps the plasma together, burning through a small focused area rather than splashing all over the target. Fortunately the bottle generators have only a small power cell, limiting the range of a pistol bolt to approximately 20 metres. Beyond this range the generators will burn out and simply disperse.

The pistol can also fire hot plasma directly from the feed without first putting it into a bolt. This cuts out most of the complicated bolt-throwing mechanism, which can suffer from misfires, and gives the weapon a secondary functionality if something breaks. Of course, without containment, the plasma disperses very rapidly due to atmospheric blooming. This firing mode will only deal significant damage out to two metres, it can save a soldier's life in close combat.

Bolts fired from this pistol is so hot that even a near-miss can be lethal. The effects on a victim are truly horrific; I will try to list them all here.

Any unarmoured human hit by a plasma bolt will suffer extreme pain and beyond-third-degree burns all across the impact area. Adipose (fatty) tissue will melt like water. Blood and other bodily fluids boil in place. The plasma will actually eat its way into a human body, chewing a hole through skin and causing bone-deep charring even ten centimetres away from the impact area. A large chunk of the body will be literally vapourised.

Any kind of tough fabric can provide some protection against a plasma hit. High-tech armour in particular will disperse the heat as best it can, and will resist being burned away by the plasma. Hopefully this will be enough time for the magnetic bottle to burn out and the plasma to disperse into the air.

I won't pretend to know how the aliens managed to squeeze all this stuff into a pistol. The mechanism appears extremely complicated for a simple handgun, but it's almost certain that larger, more powerful versions of these weapons exist and will appear against us in this war. However, my team and I have figured out the control scheme of the pistols, and we've written an appropriate field manual for human use. Our soldiers will now be able to employ the plasma pistol in a combat scenario as they would any other weapon.

--Cdr. Navarre

[Patrick Degan]

Twenty metres, with terribly complex control and power systems just to get the thing to work at all? This makes the plasma pistol a better choice of weapon than a standard .45 ACP... how, exactly?

[Einhander Sn0m4n]

Twenty metres, with terribly complex control and power systems just to get the thing to work at all? This makes the plasma pistol a better choice of weapon than a standard .45 ACP... how, exactly?

It doesn't. Plus I think I've seen this before.

[Starglider]

That's essentially a pistol calibre version of how Romulan plasma torpedoes were described in Star Fleet Battles. It was a dubious enough system at capship scales, but it really makes no sense at all at handgun scales. Given the technology to make that monstrously complex weapon, you could make weapons that put far more energy on target with much better reliability, ammo capacity and cost (probably all at once - it's that bad). Basically if the gun can generate that much hot plasma in the breech assembly, you'd be better off having it fire solid shells that explode into plasma when they hit (laser-initiated microfusion perhaps - solid state and in principle relatively cheap and simple).

The only 'plasma weapon' concept that actually makes sense is a low-velocity, high-mass-flow neutral particle beam. However this definitely looks like a beam rather than a (relatively) slowly moving blob of light.

If you must have a slowly moving blob of light, you'd be better off putting the plasma into simple quartz jars. They should last for a couple of hundred milliseconds (enough to travel 20 metres) before melting enough to lose structual integrity and explode. It would be a lot simpler than microscopic heat-proof magnetic bottle generators (which incidentally are impossible in that geometry with known physics) and more plausible than plasma-resistant plastic.

[Starglider]

That's essentially a pistol calibre version of how Romulan plasma torpedoes were described in Star Fleet Battles. It was a dubious enough system at capship scales, but it really makes no sense at all at handgun scales. Given the technology to make that monstrously complex weapon, you could make weapons that put far more energy on target with much better reliability, ammo capacity and cost (probably all at once - it's that bad). Basically if the gun can generate that much hot plasma in the breech assembly, you'd be better off having it fire solid shells that explode into plasma when they hit (laser-initiated microfusion perhaps - solid state and in principle relatively cheap and simple).

The only 'plasma weapon' concept that actually makes sense is a low-velocity (i.e. not relativistic, still many kms-1), high-mass-flow neutral particle beam. However this definitely looks like a glowing beam rather than a (relatively) slowly moving blob of light.

If you must have a slowly moving blob of light, you'd be better off putting the plasma into simple quartz jars. They should last for a couple of hundred milliseconds (enough to travel 20 metres) before melting enough to lose structual integrity and explode. It would be a lot simpler than microscopic heat-proof magnetic bottle generators (which incidentally are impossible in that geometry with known physics) and more plausible than plasma-resistant plastic.

[Starglider]

Damn I hate forgetting which forum I'm in.

[Darwin]

The only 'plasma weapon' concept that actually makes sense is a low-velocity, high-mass-flow neutral particle beam. However this definitely looks like a beam rather than a (relatively) slowly moving blob of light.

[Winter]

Thanks for the comments. I was originally thinking of turning it into a plasma beam, with a laser creating a tunnel of ionised air to make a conduit between plasma and target. After asking some opinions on that, though, the general consensus was that it would be a shame to waste the beautiful particles we've got for the plasma gun right now. I'd be open to making it a beam concept (something other than particle beams, though, we've already got PBs in a different weapons family), but then we'd need to find some other use for the current plasma gun particles. Any ideas?

Also (I mentioned this before and nobody here dared to take me up on it) I really could use the help of a physicist/weapons experts to bounce ideas off of before I write these things. Even one volunteer would help. Just post on this thread to say you're interested and we'll figure out a way to get in contact.

Regards,
Winter

[Starglider]

Thanks for the comments. I was originally thinking of turning it into a plasma beam, with a laser creating a tunnel of ionised air to make a conduit between plasma and target.

Just ionising the air won't help with a plasma (i.e. neutral particle) beam; you may be thinking of an electrolaser ('lightning gun'). However superheating the air along the path of the beam may help somewhat, in that the rapidly expanding air means less mass the main beam has to plough through to get to the target.

After asking some opinions on that, though, the general consensus was that it would be a shame to waste the beautiful particles we've got for the plasma gun right now.

Then I'd seriously suggest using quartz jars instead of magnetic bottles. They'd look like little lightbulbs in the magazine. Quartz jars containing uranium hexafluoride gas at ten thousand degrees kelvin have been seriously proposed as sustained-thrust 'nuclear lightbulb' rocket engines - they physics of that actually work with continuous cooling.

I'd be open to making it a beam concept (something other than particle beams, though, we've already got PBs in a different weapons family)

Low-velocity high-mass-flow particle beams have different properties from relativistic low-mass-flow beams, sufficiently so that it's actually reasonable to call the former 'plasma cannons' in order to distinguish them from the later.

[Zixinus]

Quick idea: How is the idea of making miniaturized positron-warheads?