Phase separation for a dense fluid mixture of nuclei

It is shown by Monte Carlo calculations that fluid mixtures of classical point ions in an uniform electron-gas background separate into two phases primarily from potential-energy considerations. For protons and $\alpha$ particles the critical temperature over an enormous pressure range is found to be near 1 eV, and only at extremely high pressures (∼${10}^8$ Mbar) does the mixture become stable. Phase separation at lower pressures, as in the interior of Jupiter (∼40 Mbar, 1 eV), is shown to be unlikely on the basis of more realistic models which modify, however crudely, the uniform electron approximation.