Review of the NPA Diagnostic Application at Globus-M/M2

The application of a neutral particle analyzer (NPA) diagnostic at the Globus-M/M2 spherical tokamaks is discussed. Physical principles of the diagnostic are reviewed. Two general approaches-active and passive measurements-are described. Examples of NPA application for the ion temperature and isotope composition measurements are presented. NPA-aided studies of the energetic ions in the MHD-free discharges, as well as in the experiments with sawtooth oscillations and toroidal Alfven eigenmodes, are considered.