Characteristic density-temperature domains at B = 10¹² G (blue online) and 10¹⁵ G (red online) for fully-ionized iron. Solid lines indicate the Fermi temperature as function of density, the dotted line shows the plasma temperature, the dot-dashed line shows the melting temperature as function of density, short and long dashes delimit the domains of strongly quantizing magnetic field and of magnetic condensation, respectively, and the heavy dots mark the critical point for the condensation (Sect. 7.3).