Fast-Ion Velocity Distributions in JET Measured by Collective Thomson Scattering

Results on fast ion diagnosis by collective Thomson scattering at JET are presented. 400 kW, 2 mm radiation was scattered in plasmas with energetic proton minority populations heated by 4--8 MW ion cyclotron resonance heating. There is clear evidence of scattering from plasma fluctuations driven by the fast ion population. In a few cases ion velocity distributions with energies in the MeV range could be inferred.