Plasma-ion diagnostics using a newly designed differential-spectrum ion-energy analyzer with electrostatic slanted grids

Ion energies, temperatures, and ion-confining potentials in open-ended plasma-confinement devices are clearly measured with our newly designed ion-energy spectrometer. This energy spectrometer has specific structures with obliquely positioned multiple grids. Such a grid geometry makes it possible to separate ions and electrons completely. This electrostatic spectrometer also has the following characteristics: (1) no use of internal magnetic fields (being different from E|B spectrometers); and (2) the use of a simple single-channel collector plate for obtaining differential ion-energy spectra (being different from energy-integrated spectra using Faraday cups). These characteristics provide us with easy handling of the spectrometer including an easy alignment of the radially scannable spectrometer in a plasma-confinement device.