dbaezner said:
Drakkith, what do you mean by fuel cells? Batteries?
I mean literal fuel cells:
https://en.wikipedia.org/wiki/Fuel_cell
A battery and a fuel cell are not the same.
Most fuel cells today use hydrogen and react it with oxygen, but you could invent some future chemical that gave a much larger output than a hydrogen-oxygen reaction if you wanted to.
dbaezner said:
The tech simply exists. I'll probably try to use the name of the tech alone to describe its operation (e.g., fusion drive, miniaturized fission core, etc.). The tricky part is getting something simple that gives off heat. It doesn't need to blow up the pilot, just cook her.
Choose your poison! Just about any concept mentioned so far can work. Just scale up the power output and/or scale down the size and you're essentially good to go. Assuming your future tech is still at least a little inefficient when it comes to thermodynamics, you're probably going to need to provide some sort of cooling, no matter what method you choose.
dbaezner said:
Ideally, I'd like to get away from fission, since it's a 20th/21st century technology (aside from miniaturizing it, of course). Fusion seems ideal, since once it is made to work (assuming it's even possible), it would probably remain a dominant form of energy production for a very long time. I just don't know enough about its principles to know if it gives off heat that has to be removed from the system. Warm fusion?
Currently, the most promising way to get power from a fusion reactor is to let the neutron radiation heat up water and then use that water to run a steam turbine that turns an electric generator. To say that fusion gives off heat is a severe understatement.
Now, the thing with fusion is that atoms don't really want to fuse to begin with. That's why it's so hard. The atoms of elements used in fission reactors will eventually decay even if you didn't put them into a reactor. There's no stopping it. All we do is put enough of it into a small enough volume that the neutrons released in the fission events run into other atoms, are absorbed, and then immediately cause that atom to fission as well, causing a chain reaction. That's why a fission reactor is so dangerous. We have to physically put barriers in place to stop the chain reaction from proceeding out of control.
But the atoms used in fusion don't want to fuse. There is a
very strong repulsive force from the nuclei that stops them from getting close enough together to fuse. We have to heat the plasma up to millions of degrees just so that a small fraction of these nuclei have enough kinetic energy to overcome this repulsive force and fuse. This makes it very, very easy to stop the reaction. It's inherently immune to the sort of dangers that fission reactors have to work very hard to prevent, such as criticality accidents and meltdowns.
That being said, technology is a fickle thing. If the right events happen in the right order, I could easily see a miniaturized fusion reactor overheating. A failure in the coolant system along with a failure in the reactor control system's sensors or something could mean that the reactor still thinks everything is okay while the entire reactor (and the ship its in) is being heated to a temperature hot enough to cook a beryllium pizza. Such a scenario is easily plausible for a fighter that has suffered damage. A single penetrating hit could damage multiple systems, causing a coolant and control system failure, preventing the pilot from ejecting, and disabling any manual control she may have had over the reactor.
