DECAY OF THE ION-CYCLOTRON INSTABILITY IN MAGNETIZED PLASMAS WITH THERMALLY ANISOTROPIC MINORITY IONS

It is well known that the temperature anisotropy of either the minorit y or majority species in a two-component plasma can make the electroma gnetic ion-cyclotron mode unstable. This instability may be particular ly relevant in tokamak experiments where high-power ion-cyclotron reso nance heating (ICRH) is used to create an energetic population of mino rity ions. We investigate the nonlinear stability of this mode and sho w that it may decay by coupling with the sound waves supported by the two species or by a modulational decay into sideband waves.