Condensation phenomena of ions in an electrostatic logarithmic trap

Abstract

The effects of an electrostatic logarithmic trap (ELT) on an ionic gas confined in a cylindric chamber are studied in detail, with special reference to the effects of the ion-ion Coulombic interactions and the resulting low-temperature thermodynamics. The collapse of the ions in radially localized states, about the axial cathode, is shown to cause an abrupt (but not critical) transition from non degeneration to strong degeneration, at a special temperature $T_c$. This transition could actually involve both Bosons and Fermions and is not to be confused with a Bose-Einstein condensation (BEC), which is excluded in principle. However, while for Bosons the resulting effects on the pressure are observable in the ultra high vacuum (UHV) regime, the Fermions' density should fall well below UHV, for the pressure change to be observable. This is because the ion-ion \emph{exchange} interactions increase the kinetic energy along the axial cathode, which makes the Fermi level and the non degeneration threshold temperature increase accordingly.