New plasma manipulation techniques are described that are central to the development of a multicell Penning trap designed to increase positron storage by orders of magnitude ͑e.g., to particle numbers N ജ 10 12 ͒. The experiments are done using test electron plasmas. A technique is described to move plasmas across the confining magnetic field and to deposit them at specific radial and azimuthal positions. Techniques to fill and operate two in-line plasma cells simultaneously, and the 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, particle numbers Ͼ10 10 in a single cell with plasma temperature ഛ0.2 eV for plasma lengths ϳ10 cm and radii ഛ0.2 cm. The updated design of a multicell positron trap for 10 12 particles is described.

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In recent work, a technique was developed to extract high quality beams from single-component plasmas confined in a Penning-Malmberg trap in a 4.8 T magnetic field. In this paper, a procedure is developed to extract these beams from the confining magnetic field and then focus them to create especially tailored electrostatic beams. Electron beams are extracted from the field in two stages: they are first transported to a region of reduced field ͑1 mT͒, and then taken to zero field with a nonadiabatic, fast extraction. Once in the field-free region, the beams are focused using an Einzel lens. Experimental results and numerical simulations are presented to illustrate the extraction and focusing process. Theoretical expressions are developed to describe the modifications to the relevant beam energy and spatial distributions. Where possible, analytic expressions are presented for the case relevant here of beams with Gaussian radial profiles. Beam emittance considerations are discussed as well as prospects for further development of these techniques. Application of these techniques to provide high-quality positron beams is also discussed.

A nondestructive technique is described to extract small-diameter beams from single-component plasmas confined in a Penning-Malmberg trap following radial compression using a rotating electric field. Pulsed beams with Gaussian radial profiles and diameters as small as 50μm are extracted from electron plasmas initially 2mm in diameter. A simple theory for the beam diameter predicts 4λD (full width to 1∕e), where λD is the Debye length, in good agreement with experimental measurements on electron plasmas. Applications and extensions of this technique to create bright, finely focused beams of positrons and other scarce particles are discussed.

In a recent communication ͓Danielson et al., Appl. Phys. Lett. 90, 081503 ͑2007͔͒, a nondestructive technique was described to create finely focused beams of electron-mass, charged particles ͑i.e., electrons or positrons͒ from single-component plasmas confined in a Penning-Malmberg trap. This paper amplifies and expands upon those results, providing a more complete study of this method of beam formation. A simple model for beam extraction is presented, and an expression for a Gaussian beam profile is derived when the number of extracted beam particles is small. This expression gives a minimum beam diameter of four Debye lengths ͑full width to 1 / e͒ and is verified using electron plasmas over a broad range of plasma temperatures and densities. Numerical procedures are outlined to predict the profiles of beams with large numbers of extracted particles. Measured profiles of large beams are found in fair agreement with these predictions. The extraction of over 50% of a trapped plasma into a train of nearly identical beams is demonstrated. Applications and extensions of this technique to create state-of-the-art positron beams are discussed.