Toroidal Alfven Eigenmodes Instability Research Articles

Orbit width scaling of TAE instability growth rate

The growth rate of toroidal Alfven eigenmodes (TAEs) driven unstable by resonant coupling of energetic charged particles is evaluated in the `ballooning` limit over a wide range of parameters. All damping effects are ignored. Variations in orbit width, aspect ratio and the ratio of Alfven velocity to energetic particle `birth` velocity are explored. The relative contribution of passing and trapped particles, and finite Larmor radius effects, are also examined. The phase space location of resonant particles that interact strongly with the modes is described. The accuracy of the analytic results with respect to growth rate magnitude and parametric dependence is investigated by comparison with numerical results

Destabilization of the shear Alfven mode by alpha particles and other high energy ions

Toroidal Alfven eigenmode (TAE) and elliptical Alfven eigenmode (EAE) instabilities in plasmas with high energy ions are considered in the context of local theory. The instability growth rate is found for cases when waves are excited by alpha particles or by ions produced as a result of neutral injection or RF heating. Electron and ion Landau damping due to the toroidal sideband wave-particle interaction is also calculated. The electron damping rate is shown to be much lower than the generally accepted value. The TAE instability observed in the experiment with neutral beam injection on TFTR is analysed and the principal experimental features of TAE instability are explained