Physics of non-thermal Penning-trap electron plasma and application to ion trapping

A modified Penning-Malmberg trap is used to produce a reflexing beam electron distribution. Positive ions are trapped in the electron space charge within a shaped anode at the center of the beam. Electron reflexing of greater than 10(6) circuits is observed, with a perveance several times that of earlier single pass devices. Classical slowing of the electron beams is observed. Two-stream instability is avoided because the emission limited space charge is subcritical. Trapped ions are observed in two modes of operation; a quiescent mode in which ions are directly counted after destroying the space charge configuration, and a rf mode in which the ion resonance instability is active. Ion inventory up to quasineutral conditions is implied for the quiescent trapping mode. (C) 2004 American Institute of Physics.