Relationship between neutron yield rate of tokamak plasmas and spectrometer measured flux for different sight lines.

A parametric relationship between total neutron yield rate and collimated fluxes related to the brightness (B) of plasma chords (λ) is developed for different emissivity distributions of tokamak plasmas. Specifically, the brightness was expressed as a function of chord coordinates of radial position using a simple model for the emissivity profiles of width parameter w. The functional brightness dependence B(λ,w) was calculated to examine the relationship between measured flux and deduced yield rate, and its plasma profile dependence.

Line integration effects on ion temperatures in tokamak plasmas measured with neutron emission spectroscopy.

The line integrated line emission measured by neutron spectrometers at JET along sight lines in the vertical and horizontal planes has been simulated in Monte Carlo calculations to determine the relationship between the measured (effective) ion temperature (T(eff)) relative to the peak value of the profile (T(0)). The general sight line dependence of (T(eff)) was expressed analytically for circular plasmas which was used to explain the simulated results for the actual JET sight lines. The analytical model with parametrization of sight lines and plasma profiles is described and the results are used to discuss dual sight line measurements that can be tested at JET and its forward implications for study burning (nearly thermal) plasmas of ITER.