Ion temperature measurements in a tokamak using active neutral particle analyzers diagnostics

Active ion temperature measurement in the core plasma of a tokamak using active neutral particle analyzers (NPA) diagnostics is considered. Two approaches for local ion temperature reconstruction are reviewed: semi-analytical and iterative. A semi-analytical approach allows the calculation of ion temperature using simple expression, while a more complex iterative approach provides more flexibility. Problems associated with active NPA measurements and their possible solutions are discussed. An example of the core ion temperature profile reconstruction in the compact spherical tokamak Globus-M2 using both approaches is shown. Problems associated with active ion temperature measurements in a compact reactor and possible solutions are considered.