Simulation of neutral particle fluxes from fast ions in the JET tokamak

摘要

Accurate determination of plasma composition is a vital measurement both in present experiments as well as eventual burning plasma operation, where control of the isotope ratio of the deuterium and tritium fuels will be critical. One diagnostic method for determining the isotope ratio is neutral particle analysis (NPA), where neutral particle fluxes resulting from charge exchange reactions inside the plasma can be used to infer the isotope ratio. The measured neutral fluxes are, however, distorted by energetic particles such as those resulting from NBI heating. The fluxes from the slowing down beam ions mask the signal from the bulk plasma, hindering analysis of the main plasma ions, with the contamination increasing with greater NBI power. The work presented here aims to characterize the neutral fluxes due to the NBI ions in order to facilitate isotope ratio measurements under these conditions.