How Iron Man's Stark Arc Reactor Would Work in Real Life
Could Tony Stark's arc reactor exist in real life? Probably not, but Gizmodo's Ryan Carlyle made a valiant attempt to explain an almost realistic version of the science behind it. As a disclaimer, he warns, "Now, I'm mixing real science and fake science here. So physics nerds and comic-book nerds: Deal with it."
The arc reactor is some kind of fusion reactor that has the ability to generate an electromagnetic field, provide clean energy, and blow things up. In the comics, Tony Stark uses it for various purposes, primarily to recharge his armor and other electronic devices. He also notably uses it in the film adaptation to power the magnet that prevents shrapnel in his chest from hitting his heart and killing him.
There is no detailed scientific (or "scientific") explanation of the mechanism behind the reactor, so we can only take an educated guess. First, Carlyle lists all the things we know about the reactor:
"-Contains a palladium core
-The palladium is damaged by neutrons, so the specific isotope is important
-Has electromagnetic coils in a torus
-Emits blue-white light
-Can be built in a cave with tools of moderate complexity
-Requires no exotic materials outside what you could scavenge from dismantled conventional weapons systems
-Runs low on power at inconvenient times, meaning it must have some sort of fuel or consumed charge"
He then observes that the reactor, as it appears in the films, does not appear to have any of the distinguishing features of a thermal reactor, such as cooling loops or turbines. As a result, it must generate electricity directly without first generating heat, which makes sense, since a thermal reactor would likely burn Tony Stark's chest.
The most important feature of the reactor is likely its palladium core. One of palladium's isotopes, Pd-107, produces silver when it undergoes a process called beta decay, in which it releases an electron when a neutron becomes a proton. In real life, there would be no net electrical current when the electron is released, because the released electron balances out the proton count between the palladium and silver. So this is where "comic book physics" would have to come in, because Tony Stark would need to come up with some kind of futuristic way to capture the electron that's released, which would generate an electric current.
"I propose that Howard Stark found a way (using comic-book physics) to utilize the beta decay of Pd-107 ions as an electron source for the electron capture of Pd-103, thereby producing an electric circuit between two different radioactive isotopes."
He theorizes that the electron capture process causes an influx of gamma waves towards the center of the reactor, while high-energy electrons are emitted from the center towards the rim. This imbalance of protons and electrons in the center would then cause a massive electrostatic potential that would afford the reactor its powers.
"Because this electron/photon counterflow creates a deficit of electrons (relative to protons) in the core, a massive electrostatic potential is developed and the palladium core attracts lower-energy electrons from the suit's wiring. The ejection of electrons from the core towards the rim of the device produces an electrical cell capable of generating enormous voltage and current."
His theory also goes a long way to explain the toxicity of the reactor, as Tony Stark was seen to suffer from palladium poisoning in Iron Man 2. First, he hypothesizes that the high-energy collisions within the reactor could easily have sent particles of the metal careening into his blood, but "this doesn't explain the freaky circuit-looking lines on his chest, and it doesn't explain why doctors can't help him."
However, another isotope of palladium's decays into rhodium, and rhodium poisoning would better explain his symptoms: "Rhodium compounds also stain skin, and are highly toxic. (Chemical properties, Health and Environmental effects) In fact, because most people have essentially zero exposure to rhodium, the toxicity of rhodium is very poorly-understood. This perfectly explains why Tony didn't seek help from the medical establishment for his accumulated heavy metal toxicity - because he knew the doctors wouldn't know how to deal with rhodium poisoning. Tony Stark didn't have simple palladium poisoning, he had "palladium decay-product" poisoning!"