Analyzing Particle Transport in a Non-Neutral Plasma Trap. Scott Rees and Brenda Carrillo

Abstract

Our research focused on particle transport, which we studied by confining non-neutral plasma in a Malmberg-Penning trap. A Malmberg-Penning trap is an apparatus that consists of an axial magnetic field and two confining end potentials. Particle transport has been the primary focus of research because the experiments that have been performed have not agreed with theory. In theory, the particles are supposed to travel along the trap's magnetic field, but experiments have shown that they drift off of the axis and into the wall of the trap. The plasma trap produces its own magnetic field, but we built a set of correction coils that would improve the field alignment and provide a more uniform magnetic field, thus improving the confinement of the plasma. Through experimentation we learned how the plasma responded to the different magnitudes of each magnetic field. Throughout the experiments, we adjusted the current flowing through the coils to improve the containment of the plasma within the trap and found that the containment improved by a factor of two to three. Although optimal values of current flowing through the coils produced greater confinement of the plasma, some instability in the plasma was still noted. Much was learned about the confinement of plasma, but further research on particle transport is needed to explain the disagreement between theory and experiment.