Quadrupole induced resonant particle transport in a pure electron plasma

Abstract

We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Malmberg-Penning trap. We have developed a model which describes the shape of the plasma and shows that a certain class of resonant electrons follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, the theory predicts that if the electrons are off resonance, the lifetime of the plasma is not greatly affected by the quadrupole field, but near resonance the lifetime diminishes sharply. Preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with the model. We are investigating the lifetime scaling with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. This resonant particle transport may be detrimental to experiments which plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Malmberg-Penning traps.