Revisiting the cylindrical positive column in an axial magnetic field

This paper seeks to bring together past and present work in this area and to remove some recent inconsistencies. It concludes that while some aspects were not completely correct in the early work, the general picture of azimuthal motion of electrons and ions is an important feature and accounts for the diamagnetism of a bounded active plasma and other features of an axially magnetised plasma. It also introduces a means of testing the equations derived by interchanging electrons and positive ions; under such a "transformation," the equations to be solved should be identical. This is a fundamental principle and is implicit in treatments given in many of the standard texts, but not made explicit.