Development and characterization of a new-type electrostatic ion-energy spectrometer and its applications for plasma ion and potential diagnostics

The radial profiles of ion currents, temperatures, distribution functions and ion-confining potentials in the open-ended plasma-confinement device GAMMA 10 are clearly measured with our newly designed ion-energy-spectrometer array. This energy spectrometer has specific structures with obliquely positioned multiple grids for obtaining ion-energy spectra without incident energetic-electron disturbance. For the precise estimation of the ion-confinement times, the absolute value of the ion-detection efficiency of the new spectrometer allay is carefully investigated using the GAMMA 10 plasmas. The characteristic features of the ion-spectrometer array for the study of ion behavior at various plasma radii are also reported along with the first data set of GAMMA 10 plasmas from the multichannel spectrometer allay.