The three-ion cyclotron resonance heating (ICRH) scheme has been recently established as an effective tool for plasma heating. One of the scenarios is based on accelerating a beam of deuterium ions in a mixed D-3He plasma at an optimal concentration of 50%-25%. In such conditions, one can effectively generate alpha particles from the d+3He fusion reactions in the core and observe the effect that alphas have on the plasma, in terms of the instabilities they induce and the impact they have on global transport. In this proceedings paper we present first results on the analysis of neutron and gamma-ray spectroscopy data to determine the deuterium distribution function obtained in JET D-(DNBI)-3He scenarios and d+3He fusion reaction rate achieved in the experiments. As far as gamma-ray emission at energies below 10 MeV is concerned, we present a procedure to identify the relative intensity of the individual lines from d+9Be and d+12C gamma-ray reactions using the full shape of the measured spectrum and show that their reactivity scales as that of the d+d neutrons. We then use the combined neutron and gamma-ray data to determine how the deuterium distribution function and d+3He rates are changed by acting on the external actuators, predominantly the RF and neutral beam injection power, and their ratio in the series of discharges performed in the experiment. We find that the d+d and d+3He fusion reactivity was tailored by acting on the deuterium distribution through the external actuators and an optimum can be achieved, whereby fusion production by d+3He reactions is close to plateau while neutron (and deuteron induced gamma-ray) emission increases. We finally provide an experimental criterion to identify the optimal alpha particle generation in D-(DNBI)-3He 3-ion scenarios for applications to alpha particle physics studies in deuterium plasmas of future devices.
Fusion Reaction Rate and Fast Ion Distribution Functions Studied with Nuclear Radiation Spectroscopy in the Three Ion D-(DNBI)-3He Scenario at JET
Dal Molin A;Rigamonti D;Tardocchi M;
2023
Abstract
The three-ion cyclotron resonance heating (ICRH) scheme has been recently established as an effective tool for plasma heating. One of the scenarios is based on accelerating a beam of deuterium ions in a mixed D-3He plasma at an optimal concentration of 50%-25%. In such conditions, one can effectively generate alpha particles from the d+3He fusion reactions in the core and observe the effect that alphas have on the plasma, in terms of the instabilities they induce and the impact they have on global transport. In this proceedings paper we present first results on the analysis of neutron and gamma-ray spectroscopy data to determine the deuterium distribution function obtained in JET D-(DNBI)-3He scenarios and d+3He fusion reaction rate achieved in the experiments. As far as gamma-ray emission at energies below 10 MeV is concerned, we present a procedure to identify the relative intensity of the individual lines from d+9Be and d+12C gamma-ray reactions using the full shape of the measured spectrum and show that their reactivity scales as that of the d+d neutrons. We then use the combined neutron and gamma-ray data to determine how the deuterium distribution function and d+3He rates are changed by acting on the external actuators, predominantly the RF and neutral beam injection power, and their ratio in the series of discharges performed in the experiment. We find that the d+d and d+3He fusion reactivity was tailored by acting on the deuterium distribution through the external actuators and an optimum can be achieved, whereby fusion production by d+3He reactions is close to plateau while neutron (and deuteron induced gamma-ray) emission increases. We finally provide an experimental criterion to identify the optimal alpha particle generation in D-(DNBI)-3He 3-ion scenarios for applications to alpha particle physics studies in deuterium plasmas of future devices.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
