Alfven eigenmodes driven by Alfvenic beam ions in JT-60U

Instabilities with frequency chirping in the frequency range of Alfven eigenmodes have been found in the domain 0.1% < [<beta>(h)] < 1% and v(b<parallel>)/v(A) similar to 1 with high energy neutral beam injection in JT-60U. One instability with a frequency inside the Alfven continuum spectrum appears and its frequency increases slowly to the toroidicity induced Alfven eigenmode (TAE) gap on the timescale of all equilibrium change (approximate to 200 ms). Other instabilities appear with a frequency inside the TAE gap and their frequencies change very quickly by 10-20 kHz in 1-5 ms. During the period when these fast frequency sweeping (fast FS) modes occur, abrupt large amplitude events (ALEs) often appear with a drop of neutron emission rate and an increase in fast neutral particle fluxes. The loss of energetic lolls increases with a peak fluctuation amplitude of (B) over tilde (theta)/B-theta. An energy dependence of the loss ions is observed and suggests a resonant interaction between energetic ions and the mode.