Stability of thermal ions confined by rigid-rotor electron clouds in Penning fusion systems

Abstract

In the Penning fusion device, a spherical cloud of electrons, confined in a Penning-type trap, creates the ion-confining electrostatic well. Calculations performed with a bounce-averaged Fokker–Planck model have suggested that highest fusion energy gains in Penning fusion systems occur when the ion population is predominantly Maxwellian. However, the question arises about the stability of the electron cloud in the presence of thermal ions. Here, a stability analysis of rigid-rotor electrons confining thermal ions is performed. The results indicate that such configuration is absolutely stable to electrostatic perturbations for arbitrary rigid-rotor electron distributions.