Different diagnostic information has been employed in JET to identify
the level of interaction between lower hybrid waves and fast ions acce
lerated up to few MeV by ion cyclotron waves. It is found that up to 2
5% of the lower hybrid power can be absorbed by fast ions under specif
ic plasma conditions. Fourier analysis of neutron emission rates and f
ast ion energy signals during lower hybrid modulation experiments show
that the level of interaction depends on the relative position of the
cyclotron resonance and the lower hybrid absorption layers.