Time resolved neutron emission spectroscopy of DT plasmas with ion cyclotron resonance heating

The energy spectrum of the DT neutron emission was measured in experiments carried out at JET for plasmas of deuterium-tritium heated with different ion cyclotron resonance heating (ICRH) schemes. The spectrum was measured with the magnetic proton recoil spectrometer. The data were analyzed in up to three spectral components, which were ascribed to the underlying reactions involving thermal, epithermal, and high-energy ions. The results include time resolved information for individual discharges. High-energy components in the fuel ion population were found in most cases and analyzed in terms of a tail temperature. Changes in the (minority) deuterium concentration in the range of 12-20% were found to affect significant the ICRH power absorption and its perturbation of the minority velocity distribution. (C) 2001 American Institute of Physics.