Measurement of spatiotemporal behavior of Alfvén-ion-cyclotron waves in the GAMMA10 tandem mirror

Spatiotemporal behavior of Alfvén-ion-cyclotron (AIC) waves excited in GAMMA10 is investigated using a microwave reflectometer and magnetic probes located at the edge. The frequency spectrum of the AIC waves has several discrete peaks. Simultaneous measurement of the internal density fluctuation and edge magnetic fluctuation of AIC waves shows that AIC waves have different radial structures in the initial excitation phase, but in the later steady state, each of them has the same structure in the radial direction. The results indicate that several AIC waves are excited as the same eigenmode in the radial direction.