Feasibility of compressing matter to electron degeneracy
So, I have been a bit disappointed with the answers on how to store degenerate matter from my previous thread, and now I'm even wondering whether one can produce it at all, without invoking unrealistic femtotechnology.
As everyone knows, to even convert regular matter into degenerate matter, requires insane amounts of pressure. Unfortunately, regular materials would certainly break after a certain amount of pressure, and the highest pressure generated in laboratory conditions is only 770 GPa (from a diamond anvil).
I came across this forum full of nuclear physicists, who realise that to make successful nuclear reactions which actually generate energy, they need electron degenerate matter, which can be used to emulate a Type Ia Supernova.
I understand well that protons fuse very very slowly (and don't get much faster either with greater compression or with CNO cycle), which means that ordinary stars can last for billions of years but that a fusion reactor using only common isotopes of hydrogen sounds difficult to achieve useful power outputs from unless it was the size of a small stellar core, even if we had Dr. Minkovsky helping us out with containment.
However, I also understand that in a type Ia supernova, "cold" gas is compressed so tightly that it becomes electron-degenerate, and that if enough additional gas is added, a portion of it eventually "flashes" to fusion very rapidly, forming a spectacular and rapid explosion. The power density is on the very, very, very rough order of 10E13 times that of the sun.
As shown here, the compression required is around 1 ton per square centimeter, not as bad as say, neutronium or quark matter. If we have theoretical strong and utterly fireproof materials (i.e. AB-Matter, Starlite, Muonic Metals, Monopolium; only slightly unobtainium) for the compressing machine, could electron degenerate matter be created with enough pressure?
If not, then is there any possible method of generating electron degenerate matter?
This post was sourced from https://worldbuilding.stackexchange.com/q/165945. It is licensed under CC BY-SA 4.0.
1 answer
Use low temperatures.
For a given system, we can tell if degeneracy pressure is important by comparing the Fermi energy $E_F$ to the thermal energy $kT$. if $E_F\gg kT$, the gas is fully degenerate; even $E_F\sim10kT$ will apparently lead to at least partial degeneracy. As the Fermi energy scales as $E_F\propto \rho^{2/3}$, and (non-relativistic) degeneracy pressure scales as $P\propto\rho^{5/3}$, where $\rho$ is density, it should be clear that if your substance is quite cold, you can achieve degeneracy at lower pressures.
Consider a gas of electrons at $T\sim 10\text{ K}$. This has a thermal energy of $kT\approx8.6\times10^{4}\text{ eV}$. Let's assume that full degeneracy occurs at a Fermi energy of $E_F\approx100kT$. This requires a surprisingly low density - only $\rho\approx1.05\times10^{-7}\text{ g cm}^{-3}$. Calculating the degeneracy pressure shows that $P\sim10\text{ Pa}$, which is clearly substantially easier to achieve.
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