About the dynamics and thermodynamics of trapped ions

TL;DR

This paper reviews the dynamics and thermodynamics of trapped ions, comparing quadrupole and multipole traps, and introduces a fluid model to analyze large ion samples considering Coulomb interactions.

Contribution

It proposes a fluid modeling approach for large ion clouds in traps, extending methods from Penning trap studies to various trap geometries.

Findings

Fluid model effectively scales ion cloud size with trap parameters.

Coulomb interactions significantly influence ion dynamics in dense samples.

Differences between quadrupole and multipole trap dynamics are highlighted.

Abstract

This tutorial introduces the dynamics of charged particles in a radiofrequency trap in a very general manner to point out the differences between the dynamics in a quadrupole and in a multipole trap. When dense samples are trapped, the dynamics is modified by the Coulomb repulsion between ions. To take into account this repulsion, we propose to use a method, originally developed for particles in Penning trap, that model the ion cloud as a cold fluid. This method can not reproduce the organisation of cold clouds as crystals but it allows one to scale the size of large samples with the trapping parameters and the number of ions trapped, for different linear geometries of trap.