Measurement of the ion temperature in a hot plasma by fast atom scattering

Potentialities of the method for local measurements of ion temperature in a hot plasma have been analyzed by scattering fast atoms injected in the form of a narrow monokinetic beam. The factors are considered which affect the choice of the form and energy of monitoring atoms and angle of scattering, and also the requirements for the parameters of an injected beam and a detecting instrument. A helium atom beam 8 keV, the current density 10 mA/cm2 and the pulse duration of 200 μs have been used. The scattering angle being 9 deg. The spatial resolution 9-10 cm in the direction along the beam and 1 cm in the transverse one. The ion temperature obtained is in a good agreement with the temperature measurements taken by other methods of corpuscular diagnostics. It has been shown that the method makes it possible to measure the ion temperature in the volume, which is small as compared with the dimensions of the transverse section of a plasma. An essential advantage of the method is that it can be used for measuring temperature of the main group of ions and is not sensitive to possible disturbances of the ion distribution function in the range of energy much exceeding the mean thermal one. This makes it attractive for applying in studying the supplementary plasma heating in tokamaks