Neutron spectrometry of radio-frequency heated deuterium-tritium plasmas

Spectrometry of the neutron emission has been used to probe the nonthermal features of the fuel ion velocity distributions in tokamak plasmas, especia lly, those arising from auxiliary heating. The first time resolved measurem ents are reported from the use of the new magnetic proton recoil (MPR) spec trometer in observations of deuterium-tritium plasmas at JET with strong io n cyclotron resonance heating. Results from preliminary analysis data are p resented and compared with simulated neutron emission spectra based on the assumptions of a thermal plasma (a single Maxwellian ion distribution! or a nisotropic Maxwellians with parallel and perpendicular temperatures, beside their relative amplitudes. The diagnostic results attained are also used t o assess the diagnostic capabilities and the potential for use of MPR based diagnostics on burning plasma tokamaks. (C) 1999 American Institute of Phy sics. [S0034-6748(99)53401-1].