Regular Article

A new ion–ion plasma thruster with an annular geometry^★

CNRS, ICARE, EP Team, 1c Avenue de la recherche scientifique, 45100 Orléans, France

^a e-mail: stephane.mazouffre@cnrs-orleans.fr

Received: 5 September 2017
Received in final form: 4 October 2017
Published online: 21 November 2017

Abstract

The concept of ion–ion plasma thruster relies on a magnetic filter to create an electron-free plasma in the ion current extraction region. However, experiments and computer simulations show that a transverse magnetic field makes the discharge asymmetrical due to electron drift and instabilities in the region of strong magnetic field. The drift drives a large electron flux to the walls, therefore increasing losses, and reduces the electron confinement by creating an escape path throughout the magnetic filter, which is detrimental for the thruster performances. We present a new architecture for an ion–ion plasma thruster that allows to cancel the asymmetry of the plasma by closing in the electron drift on itself. The concept is termed AIPE, an acronym for Annular Ion–ion Plasma Engine. A prototype was developed and tested with noble gases and SF₆. Outcomes of experiments dedicated to the examination of the AIPE discharge and beam by means of Langmuir probe, E×B probe and laser photodetachment are given and discussed. It is shown that the discharge is symmetrical and homogeneous. In addition, positive and negative ions can be extracted and accelerated through the grid assembly.