Probe wave system for studying excitation of Alfven eigenmodes in the ion cyclotron range of frequency

A probe wave system was constructed for studying the excitation of the Alfv en ion cyclotron (AIC) modes in the anchor cell of the GAMMA 10 tandem mirr or. In the central cell, the AIC modes are spontaneously excited as axial e igenmodes due to the strong temperature anisotropy. In the anchor cell, the AIC modes were not observed though the anisotropy is the same as in the ce ntral cell. The axial profiles of the magnetic field strength and plasma pa rameters in the anchor cell are different from those in the central cell. E igenmodes are excited externally in the AIC frequency range by injecting pr obe waves. This suggests the AIC modes are unstable in the anchor cell and grow to the detectable level when boundary conditions are realized. (C) 200 1 American Institute of Physics.