Enhancement of negative ion extraction and electron suppression by a magnetic field

Abstract

We report experiments of extracting negative and positive ions and electrons from a multicusp volume ion source. The effect of a transverse magnetic field in front of the plasma electrode is reported for the three extracted species when the bias of the plasma electrode is changed. Also the effect of the discharge current and of the pressure are reported. The experiments indicate that the effect of the magnetic field is to enhance the negative ion current and to suppress a great part of electrons from the extracted current. An explanation based on electron behavior in the magnetic field is proposed.