Neutron spectroscopy measurements and modeling of neutral beam heating fast ion dynamics

Abstract

The energy spectrum of the neutron emission from beam-target reactions in fusion plasmas at the Joint European Torus (JET) has been investigated. Different beam energies as well as injection angles were used. Both measurements and simulations of the energy spectrum were done. The measurements were made with the time-of-flight spectrometer TOFOR. Simulations of the neutron spectrum were based on first principle calculations of neutral beam deposition profiles and the fast ion slowing down in the plasma using the code NUBEAM, which is a module of the TRANSP package. The shape of the neutron energy spectrum was seen to vary significantly depending on the energy of the beams as well as the injection angle and the deposition profile in the plasma. Cross validations of the measured and modeled neutron energy spectra where made, showing a good agreement for all investigated scenarios.

Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

“…This result is consistent with the findings of the PION simulation and emphasises the need for self-consistent simulations to analyse ICRF heating in the utilised scenario. Simulated deuterium distribution functions are first compared with the signal from the TOFOR neutron spectrometer [36] via the calculation of the neutron emission spectrum using a Monte Carlo method as described in [37]. The initial comparison between the ASCOT/RFOF and SPOT/RFOF reconstructed signals and the TOFOR measurements is shown in Fig.(9).…”

Modelling neutral beams in fusion devices: Beamlet-based model for fast particle simulations

“…It has been extensively used for modelling both AUG [20,21] and JET [22,23,24] plasmas. PENCIL [9] on the other hand, has been the standard tool for simulating neutral beams at JET since early 1990s.…”

Fast ion energy distribution from third harmonic radio frequency heating measured with a single crystal diamond detector at the Joint European Torus

“…They can be used to extract essential parameters for machine control, such as the fuel ion temperature, 1 the thermal/non-thermal components of the neutron emission, 2,3 and the fuel ion ratio. 4 More recently, they have contributed to fundamental studies on the physics of suprathermal ions in thermonuclear plasmas, mostly by detailed measurements of the distribution function of the energetic ions [5][6][7] and their effects on the plasma stability.…”