Could arc reactors eventually be real? I have wondered about this, there is not much about it online. If they could how would they work?
There are efforts to build small nuclear reactors which we can use in our homes. The effort is to use LENR technology. As for whether arc reactors can eventually be real, then we could wait for engineering innovations and scientific discoveries under the condition that
The short answer is We don't know yet.
Readings: The nuclear reactor in your basement http://climate.nasa.gov/news/864
NASA’s cold fusion tech could put a nuclear reactor in every home, car, and plane http://www.extremetech.com/extreme/149090-nasas-cold-fusion-tech-could-put-a-nuclear-reactor-in-every-home-car-and-plane
Well, no, such a thing cannot be made because it is a fictional concept. You ask "how would they work," and the reason you can't find any information is that arc reactors are plot devices and nothing more. Science will never invent a way to harness energy from writers' imaginations (or lack thereof) the same way the arc reactor can.
If you want a more scientific answer, you have to be more specific with what you are looking for. Do you want a small supply of useful energy? We have those; they're called batteries. Do you want a power supply that glows? One that runs on fission? Fusion? Higgs bosons? Those are valid questions. Of course you can never have a device that runs on nothing, producing power without any fuel.