Fusion reactor designs and data analysis

By measuring the neutron emission from the plasma, it is possible to obtain information about the various properties of the fuel ions deuterium (D) and tritium (T) in a fusion plasma. Neutrons are produced in fusion reactions between fuel ions; This means that the density and energy spectrum of the emitted neutrons are related to the densities and velocity distributions of these ions. This thesis describes different methods for analyzing data from fusion neutron measurements. The main focus is on neutron spectrometry measurements using data collected at the tokamak fusion reactor JET in the UK. Several neutron spectrometers are installed on the JET, including the TOFOR time-of-flight spectrometer and the magnetic proton recoil (MPR) spectrometer. Part of the work is concerned with computation of neutron spectra from given fuel ion distributions. Most of the related fusion reactions, such as D + T and D + D reactions, have two particles in the last case, but there are also examples where three particles are produced, e.g. In the T + T reaction. In this thesis, both two- and three-body reactions are considered. A method has also been developed to incorporate the finite Larmor radii of fuel ions into the spectrum calculation. This effect was found to significantly affect the shape of the measured TOFOR spectrum for a plasma scenario using ion cyclotron resonance heating (ICRH) combined with neutral beam injection (NBI). Using the ability to calculate neutron spectra, it is possible to construct different parametric models of neutron emission for various plasma scenarios. In this thesis, such models are used to predict fuel ion density in plasmas heated with NBI and fast D distribution in plasmas with ICRH.