Additional stability regions in a plasma column with an inflection point

An open ended device with a non-planar magnetic axis is described. A system with a non-planar axis has its own merits compared with a planar axis. An additional stability region, which is one of the characteristic features for this system, has been found out experimentally in a current-carrying plasma column. This region can be realized only in such a way as an additional current with a sufficient fast rise time is superposed to a current-carrying stable plasma column. (author)