Non-congruent Phase Transitions in Cosmic Matter and in the Laboratory
  Non-congruence appears to be the most general form of phase transition in
cosmic matter and in the laboratory. In terrestrial applications
noncongruencemeans coexistence of phases with different chemical composition in
systems consisting of two (or more) chemical elements. It is just the case for
all phase transitions in high-temperature chemically reactive mixtures, which
are typical for uranium-bearing compounds in many nuclear energy devices, both
contemporary and perspective. As for cosmic matter, most of real and
hypothetical phase transitions without nuclear reactions, i.e., those in the
interiors of giant planets (solar and extrasolar), those in brown dwarfs and
other sub-stellar objects, as well as in the outer crust of compact stars, are
very plausible candidates for such type of phase transformations. Two exotic
phase transitions, the gas-liquid phase transition in dense nuclear matter and
the quark-hadron transition occuring in the interior of compact stars as well
as in high-energy heavy-ion collisions are under discussion as the most extreme
example of hypothetical non-congruence for phase transformations in High Energy
Density Matter.
