Plasma Manipulation Techniques for Positron Storage

Described here are new plasma manipulation techniques central to the development of a multicell Penning trap\footnote{C. M. Surko and R. G. Greaves, {\it Rad. Phys. Chem.} {\bf 68}, 419 (2003).} that is designed to increase positron storage by orders of magnitude (e.g., to particle numbers N $\geq 10^{12}$). The experiments are done using test electron plasmas. A technique is described to move plasmas across the confining magnetic field and dump them at specific radial and azimuthal locations. Techniques to fill and operate two in-line plasma cells simultaneously and use of 1 kV confinement potentials are demonstrated. These experiments establish the capabilities to create, confine, and manipulate plasmas with the parameters required for a multicell trap, namely N $\geq$ $10^{10}$ in a single cell with temperatures $\leq$ 0.2 eV, plasma lengths $\sim$ 10 cm and radii $\sim$ 0.2 cm. The updated design of a multicell positron trap for $10^{12}$ particles is described. Potential applications, including prospects for a portable positron source (i.e., to replace conventional isotope and accelerator-based sources) will be discussed.