Plasma Parking into Off-axis Storage Traps

Advanced uses of positrons benefit by the development of efficient techniques for particle accumulation, storage and delivery.\footnote{J. R. Danielson, et al., {\it Rev. Mod. Phys.} {\bf 87}, 247 (2015).} The multicell Penning-Malmberg trap is being developed as a way to obtain high-capacity antimatter traps.\footnote{J. R. Danielson, et al., {\it Phys. Plasmas} {\bf 13}, 125002 (2006).} The multicell test structure at UCSD consists of multiple aligned storage cells, with one cell on the magnetic axis, and three off-axis.\footnote{C. J. Baker, et al., {\it Phys. Plasmas} {\bf 22}, 022302 (2015).} Described here are tests of the process by which plasma, first located in a large diameter master cell, is autoresonantly excited into a large amplitude diocotron mode and then transferred into off-axis cells. Through the use of bounce-average orbits\footnote{N. C. Hurst, et al., {\it Phys. Rev. Lett.} {\bf 113}, 025004 (2014).} and other manipulation techniques, the plasma position during transfer can be controlled precisely, and the plasma can be ``parked'' at any radial or azimuthal location within a storage cell. Other experiments in the test structure, including plasma lifetime studies and experiments with large space charge, will also be described.