A Bisection Break-Up Theory for Cluster Ions and Its Application to the Design of Mean Specific Size Controllers

Abstract

The most important condition for additional heating of high temperature plasmas and refuelling of fusion reactors using energetic cluster ions is to give the proper energy to each constituent atom. This can be done by controlling their specific sizes and by accelerating the cluster ions by an appropriate voltage. A bisection break-up theory, in which cluster ions are assumed to be divided into two equal fragments by electrostatic repulsion arising from multiple ionization by electron impact is proposed for the first time. The purpose of this theory is to obtain the relation between the mean specific size and the electron current. The theory gives good agreement between the theoretical and the experimental values of the mean specific size of nitrogen cluster ions, demonstrating its applicability to the design of mean specific size controllers.