Modal and discrete focusing effects associated with three-dimensional plasma-sheath-lenses show promising potential for applications in ion beam extraction, mass spectrometry, plasma diagnostics and for basic studies of plasma sheath. The ion focusing properties can be adjusted by controlling the geometrical structure of the plasma-sheath-lens and plasma parameters. The positive and negative ion kinetics within the plasma-sheath-lens are investigated both experimentally and theoretically and a modal focusing ring is identified on the surface of disk electrodes. The focusing ring is very sensitive to the sheath thickness and can be used to monitor very small changes in plasma parameters. Three dimensional simulations are found to be in very good agreement with experiments.
Bibliographical noteCopyright 2015, American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in (Applied Physics Letters 107 (2015) 094106) and may be found at http://scitation.aip.org/content/aip/journal/apl/107/9/10.1063/1.4930063.
Stamate, E., & Yamaguchi, M. (2015). Fine structure of modal focusing effect in a three dimensional plasma-sheath-lens formed by disk electrodes. Applied Physics Letters, 107(9), . https://doi.org/10.1063/1.4930063