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[personal profile] vitruvian23
 Going to start posting here again, partly because I've already friended some folks on LJ and partly because of the ease of doing an lj-cut.

Anyway, I've been Googling commentary on the Iron Man movie, specifically the major technological MacGuffin - the arc reactor. And nobody seems to have put as much thought into it as me. Maybe that should tell me something...

All the rest of the Iron Man technology - boot jets, repulsor beams, everything - hinges on the energy output of Tony Stark's miniaturized arc reactor. The prototype built in the cave is quoted as putting out '3 gigajoules per second', otherwise known as 3 gigawatts, of power - but it's then immediately made clear that that's a peak output for a limited time only, since he says it can power something big for '15 minutes'.

The device is small, so it basically needs to be some type of nuclear energy or something even more exotic, such as matter-energy conversion or zero-point energy. The original, mammoth arc reactor back at Stark Industries looks like some kind of glass-walled tokamak, which points us towards fusion, and the central ring of the miniature version is made of palladium, clearly meant to imply a connection of some kind with the Pons/Fleischmann cold fusion fiasco. So, say it's some type of nuclear fusion - that would produce the required amount of energy while only 'burning' milligrams of hydrogen (which could be extracted from water vapor in the atmosphere, or from a tiny reservoir of water not shown, or infused in the palladium core - palladium is also being looked at for hydrogen storage, although I'm not sure 2 grams of the stuff could hold enough hydrogen to do 3 gigawatts for 15 minutes).  What else can we figure out about it?

First off, the fusion reaction used needs to aneutronic, or nearly so, since he doesn't seem to have any worries about dying of radiation poisoning within a couple days, and there's not nearly enough room in the device for neutron shielding. Any reaction with hard gammas as a major product is probably also out, unless he's also invented perfect shielding/photovoltaic tech for capturing electromagnetic waves of arbitrarily high energy levels. That basically leaves charged particles (protons or electrons, conceivably positrons) with high energies that can be captured and have their energy extracted directly to electricity, rather than running a heat engine. This is probably desirable for other reasons we'll see below.

Obviously the electrical power output can either be dialed up or down, or stored somehow until needed - he doesn't need anything like a gigawatt for the electromagnet used to keep shrapnel out of his heart, in fact the stuff would be ripped right out of him with probably lethal results. 

The arc reactor got to be ridiculously efficient, both in production of energy and extraction of energy for electrical current, since he doesn't get fried by waste heat every time he dials up the power output. Maybe the armor has some kind of cooling mechanisms, but that wouldn't help too much with the issue that the generator is embedded right in his chest.  All that power gets extracted through a really small electrical cable, although maybe that's just the lead to the electromagnet - but even so, the available surface for the sides of the reactor to interface with his armor's electrical power systems isn't that much greater. So, again that suggests some kind of reaction that results in high energy charged particles that get captured for electrical power - less opportunity for waste heat. However, in order for the waste heat to be effectively nil, he's pretty much got to have room temperature superconductors, so that the thing doesn't melt just from electrical resistance in its wiring.

If we assume that he's got superconduction nailed already (and uses it in his missiles, since otherwise he wouldn't have the right stuff to scavenge), that actually explains a lot. However much energy the arc reactor can put out, he can use for his armor's systems without fear of overheating, at least depending on *how* it gets used. He might even be able to store energy that he's not ready to use yet in arbitrarily large quantities inside a superconducting loop, as an alternative to any type of conventional battery technology. It might even help explain how he gets a fusion reaction going in the first place.

First off, with superconducting cables, he can probably throw a *lot* of current into that palladium ring. Since palladium is not itself a superconductor, there's resistance, which means high voltage. High voltage translates into high energies for electrons, and possibly for other particles, which could potentially translate into the ability to overcome the Coulumb barrier to a fusion reaction, regardless of how high the temperatures would have to be to make this work in a more conventional reactor. It sounds more and more like the arc reactor works on the basis of accelerating hydrogen ions or something similar to fuse inside the palladium ring, spitting out even more energetic, heavier ions.

Second, being able to produce a room temperature superconductor suggests a lot more understanding of the nature of conductive metals with various dopants than we currently have in the real world. There might be some trick involving quantum tunneling or something similar, where the usual charge barrier to achieve an exothermic fusion reaction doesn't actually have to be breached, but can be sidestepped. In fact, the point where his superconducting cable actually meets up with the regularly conducting palladium ring might be key here.

Another thought - the blue glow constantly emitting from the arc reactor may also be telling. It looks a whole lot like Cerenkov radiation, which is what you get when a charged particle passes through an insulator at a speed greater than the speed of light through that medium. This usually happens when the particle(s) pass from an area where the speed of light through the medium (not to be confused with the speed of light in a vacuum, which is invariant) is relatively high, into a medium where it is relatively low (which would be due to various types of interactions with the atoms and electrons in the medium). So, the blue glow could be happening when electrons (which could presumably be circulating at or near the speed of light in a superconductor) get introduced to the central power core, or alternatively when protons or ions exit the fusion reaction at high speeds and then get slowed down as they interact with the outer parts and get captured for power extraction. Either way, it's a neat thought experiment.

That just leaves the limited lifespan of the device at peak power output. This can't simply be a matter of running out of hydrogen or other fuel to power the fusion reaction, since such fuel could surely be replenished - although that might require completely powering the device down, infusing it with hydrogen ions, and then starting it up again, which one imagines could be a finicky process (note that even the one Stark plans to be decommissioned is left running the whole time it functions only as a display item). Okay, maybe that 15 minute lifespan is just without refueling. On the other hand, perhaps running the thing at peak power actually degrades the device in some measurable way -whether that's gradually knocking the palladium atoms out of alignment, breaking down the superconductors, filling up voids with the wrong types of ions or charged particles (there might be a problem with positrons being one of the reaction products, for example - an opportunity for Stark to invent positronic circuitry next), or what have you.

Of course, even if the arc reactor is forever limited to providing 12 gigawatts of power (the second model is supposedly about four times as powerful) for no more than 15 minutes or so (although one gets the sense the new model has a longer factory warranty too), that's still a good 3 gigawatt-hours of lifetime energy production for a device the size of a hamburger, one which Stark was able to put together from scraps as Uncle Obadiah said. The use of palladium is not a major constraint on manufacture, since it uses only a few grams and current prices are in the $500 per ounce range. Perhaps the other components are more expensive. After all, superconducting cables designed for use in multimillion dollar 'repulsor' missile systems might even run you a million or two in manufacturing costs themselves. Even so, 3 gigawatt-hours is equal to 3 million kilowatt-hours, for which the current average price in the US is about $0.10, so the cost per unit (even once mass production is in place) would have to be higher than $300k in order for it *not* to make sense for Stark Industries to enter the power industry. Now, that would be a different way to save the world.

Date: 2008-06-16 06:32 pm (UTC)
From: [identity profile] amonitrate.livejournal.com
here because I googled looking for how the arc reactor supposedly works, and you are awesome. Thanks for putting thought into it!

Date: 2008-06-16 07:31 pm (UTC)
From: [identity profile] dejla.livejournal.com
Wow. That is so cool.

Date: 2008-06-16 07:34 pm (UTC)
From: [identity profile] teresa-c.livejournal.com
You are freaking awesome. (Here from [livejournal.com profile] amonitrate's journal.)

Date: 2008-06-16 07:49 pm (UTC)
From: [identity profile] vitruvian23.livejournal.com
Next up - the Incredible Hulk and conservation of mass.

Date: 2008-06-17 12:23 am (UTC)
From: [identity profile] quigonejinn.livejournal.com
Also here from [livejournal.com profile] amonitrate, and my God, this is absolutely brilliant.

Date: 2008-06-17 01:25 am (UTC)
From: [identity profile] ferricent.livejournal.com
This is fantastic. It's such a cool thought experiment and you've presented your ideas in a way that's both informed and comprehensible for someone like me, who only has a little knowledge of thermodynamics, physics, etc. Thanks for writing/posting this.

Date: 2008-06-17 01:53 am (UTC)
From: [identity profile] jmtorres.livejournal.com
Fascinating.

So I have this friend (http://basingstoke.livejournal.com/361640.html) who wants to know why it behaves like a pacemaker, ie, Tony's heart stops when you pull out the arc reactor, if it's really doing the magnet thing on the shrapnel. Any thoughts?

Date: 2008-06-17 02:12 am (UTC)
From: [identity profile] vitruvian23.livejournal.com
Short answer: No, it does not make any earthly medical sense. I mean, even if there is room for his heart to still be in there, how much of Stark's ribcage around the sternum did Yinsen need to remove to make room for that deep metal tube?

Slightly longer answer: Of course, the whole idea of keeping shrapnel out of the heart with an electromagnet does not really make sense, and never has done. However, going with the premise that, somehow, there are little shards of metal too small to get out, that are still big enough to trigger a heart attack if they get inside the ventricles, and somehow the magnet can be calibrated to hold them in place without pulling them out straight through his flesh... then I'd say what is happening in that scene is not that his heart has actually *stopped*, per se, but as the electromagnet is losing its pull (won't happen immediately, as by now it'll have some permanent magnetism), perhaps some of the smaller fragments are migrating and he's feeling the beginnings of some mini-heart attacks. Of course, "too weak to walk or reach up on a table but still strong enough to smash glass and do open heart surgery on oneself" is diagnostic of a heart attack only in the movies, but I think we can agree that if his heart had actually *stopped* at any point, he wouldn't have been moving or conscious at all, even once the paralysis thingie wore off.

So, my answer - heart rhythm disrupted, blood flow impeded, but heart doesn't actually stop at any point.

Of course, this being Stark, I wouldn't put it past him to have added in a pacemaker and an automatic defibrillator in there along with the magnet while he was playing around with the power source.

Date: 2008-06-19 01:38 pm (UTC)
From: [identity profile] seren-ccd.livejournal.com
Wow. Thank you! Thank you very, very much. Husband and I have been discussing this off and on since the movie and your summary is exactly what I needed. And your explanation above about the 'heart attack' feels really spot on. Thank you for reseaching this.

Date: 2010-02-26 01:57 am (UTC)
From: (Anonymous)
I know it is a really old post but I just got a question that has since bugged me after watching the movie for the 12th time. Seeing that you have been able to come up with a theory on how the reactor works, I figured you can come up with an answer:

When Stark decides to change his reactor, we saw how Pepper removes the old reactor along with an electromagnet but replaces with just a new reactor. I am assuming that the new reactor contains a built in electromagnet. What puzzles me is when Stark is forced to use his old reactor, he does it without an electromagnet?

Date: 2010-03-02 01:22 am (UTC)
From: [identity profile] vitruvian23.livejournal.com
I don't know that we ever see him actually inserting the old one into his chest cavity; in fact, I seem to recall a fade to black immediately after he pulls down the old reactor's 'trophy' case and shatters it. The electromagnet might even have been in there, I don't know if we get a good enough look at the display to tell.

Confusion

Date: 2010-04-19 09:56 am (UTC)
From: (Anonymous)
please stop confusion the power output 3 gigajoules is nowhere near 3 gigawatts i am an electrician a joule is a minute amount of power over time hence you dont say joules per second its just joules in terms of watts 3 gigajoules is about 850 kilowatt hours which considering its size is still extremely great but its a far cry from 3 gigawatts

Re: Confusion

Date: 2010-04-19 01:47 pm (UTC)
From: [identity profile] vitruvian23.livejournal.com
Somebody needs to brush up on their SI units. A watt is indeed defined as one joule per second. Certainly, it would be highly unusual for 3 gigajoules of energy to be expended over one second for a power of 3 gigawatts, but if it were to be used that quickly, that would indeed be the power output.

Power output is energy/time, so you can't determine power from energy without knowing what time period you're talking about. Unfortunately, the script for Iron Man confuses the concepts of power and energy, making it difficult to determine what the stats for the arc reactor would actually.

Re: Confusion

Date: 2010-04-19 01:48 pm (UTC)
From: [identity profile] vitruvian23.livejournal.com
The script says "3 gigajoules per second". How would you calculate that power output?

Date: 2010-05-03 12:00 pm (UTC)
From: (Anonymous)
wow your good

Just some thought?

Date: 2010-05-22 06:47 am (UTC)
From: (Anonymous)
Everything you said makes a hell a lot of sense but you can't seem to figure some parts out. Like where you say "That basically leaves charged particles (protons or electrons, conceivably positrons) with high energies that can be captured and have their energy extracted directly to electricity, rather than running a heat engine." and "So, again that suggests some kind of reaction that results in high energy charged particles that get captured for electrical power - less opportunity for waste heat." and "He might even be able to store energy that he's not ready to use yet in arbitrarily large quantities inside a superconducting loop, as an alternative to any type of conventional battery technology."

Have you considered Uranium-238? Uranium-238 captures neutrons and after two beat decays becomes fissile Plutonium-239. Not to mention Uranium-238 has a half life of about 4.468 billion years and produces 600 megawatts. But Uranium only becomes Plutonium-239 if the hydrogen molecules are not able to be kept up on a repeating patter, this is because there isn't enough energy to keep it going. This is where you introduce a catalyst to speed up the hydrogen ions. The Palladium acts as the catalytic converter (meaning the catalyst is the Palladium). The Palladium will keep speeding up the Hydrogen Ions Keeping the Uranium-238 in is present state. The Palladium can then Convert the left over Hydrogen Ions into electrical energy along with the energy the Uranium-238 produces. Put the two together along with the rest of your theories and you get the Arc Reactor. Now this is only my point of view please email me letting me know if this helps any. (cdthomas93@yahoo.com)

Re: Just some thought?

Date: 2010-05-22 04:25 pm (UTC)
From: [identity profile] vitruvian23.livejournal.com
How much U238 do you think it takes to produce 600 megawatts, even when converted to P239, though? Quantities matter, and the observed size of the arc reactor is a limiting factor. Sorry, fission, even catalyzed by fusion, won't cut it here.
From: (Anonymous)
I have looked every where even on wiki and can't find anything about
From: [identity profile] vitruvian23.livejournal.com
Using magnetic or electrical fields. Essentially, just as you can use magnetic or electrical fields to accelerate charged particles, you can likewise use them to extract energy from charged particles already in motion with a lot of energy by slowing them down, turning that energy into electricity. The magnetic version is called magnetohydrodynamic power conversion or generation

http://en.wikipedia.org/wiki/MHD_generator

https://wiki.engr.illinois.edu/download/attachments/19302147/Duchek+-+Direct+Energy+Conversion.ppt?version=2&modificationDate=1241712650787

Date: 2012-09-23 05:09 am (UTC)
From: [identity profile] gjfz722.livejournal.com
ути-пути Подробнее... (http://www.ohotnik.dn.ua/statusicon/category/)
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