Condensation phenomena of ions in an electrostatic logarithmic trap

TL;DR

This paper investigates how ions behave in an electrostatic logarithmic trap, revealing a non-critical transition from non-degenerate to strongly degenerate states influenced by Coulomb interactions, with implications for both Bosons and Fermions.

Contribution

It provides a detailed analysis of ion condensation phenomena in an ELT, highlighting a transition mechanism distinct from Bose-Einstein condensation and its dependence on ion interactions.

Findings

Collapse causes a transition at temperature T_c

Transition affects pressure observable in UHV for Bosons

Fermion density and pressure are influenced by exchange interactions

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.