Theoretical analysis of the space charge effect in linear ion trap

An ion trapped in the linear ion trap will undergo secular motion with special frequency related to the radio frequency field. With increasing number of ions in the trap, space charge effect will cause Coulomb force between ions and result in motion frequency shift. In this paper, we use Possion's equation to solve the extra electric field due to space charge and discuss the effect of this electric field on ion motion frequency. In the end, we also discuss the relationships between ion clouds numbers, ion clouds temperature and experimental parameters. All this work would be meaningful in frequency standards ion experiments as well as collision research. (authors)