PHASE-EQUILIBRIUM IN A CURRENT-CARRYING LIQUID CONDUCTOR IN Z-PINCH GEOMETRY

A cylindrical liquid conductor at constant temperature with an axisymm etric de current generating an azimuthal magnetic field is studied. Th e magnetic field introduces an additional field component that is diff erent for each phase in the total chemical potential. It is shown that treatment of the field components can be reduced to equating the chem ical potentials of the matter in different phases without a field at d ifferent pressures. As a result of the shift appearing in the paramete rs of phase equilibrium, the liquid not heated up to boiling coexists with gas at pressures corresponding to the metastable branch of the st ate parameters. For this reason, there exists a limiting value of the current above which phase equilibrium is impossible in this geometry. In the latter case, a transition of the system into a dispersed state (drops in vapor) followed by mechanical breakup of the fluid column on account of the energy stored in the magnetic field occur. The expansi on rate, drop size, and current at which this phenomenon occurs are es timated. The phenomenon can occur in the final stage of the fast elect rical explosion of conductors. (C) 1997 American Institute of Physics.