Fusion product studies via fast ion D-D and D-~3He fusion on JET

摘要

Dedicated fast ion D-D and D-~3He fusion experiments were performed on JET with carbon wall (2008) and ITER-like wall (2014) for testing the upgraded neutron and energetic ion diagnostics of fusion products. Energy spectrum of D-D neutrons was the focus of the studies in pure deuterium plasmas. A significant broadening of the energy spectrum of neutrons born in D-D fast fusion was observed, and dependence of the maximum D and D-D neutron energies on plasma density was established. Diagnostics of charged products of aneutronic D-~3He fusion reactions, 3.7 MeV alpha-particles similar to those in D-T fusion, and 14.6 MeV protons, were the focus of the studies in D-~3He plasmas. Measurements of 16.4 MeV gamma-rays born in the weak secondary branch of D(~3He, γ)~5Li reaction were used for assessing D-~3He fusion power. For achieving high yield of D-D and D-~3He reactions at relatively low levels of input heating power, an acceleration of D beam up to the MeV energy range was used employing 3rd harmonic (f= 3f_(CD)) ICRH technique. These results were compared to the techniques of D beam injection into D-~3He mixture, and ~3He-minority ICRH in D plasmas.