Excitation of kinetic reverse shear Alfven eigenmode by energetic ions in a tokamak plasma

We have analyzed the excitation of kinetic reverse shear Alfven eigenmodes (KRASEs) by resonating hot ions in a tokamak plasma with a reverse shear profile. Inclusion of non-ideal effects such as parallel electric field and finite ion Larmor radius provide the regime for excitation of KRSAEs through the inverse ion Landau damping. Reduced kinetic magneto-hydrodynamic equations are solved numerically by a kinetic Alfven eigenmode solver (KAES) code. Even and odd KRSAEs exist inside the Alfven continuum near qmin surface and develop by radial trapping of kinetic Alfven waves. We traced the real frequency and growth rates of KRSAEs with respect to the energetic ion βEP, normalized gradient scale length (LnEP/a) and thermal velocity, (vthEP/vA0) for the first four radially trapped modes. Real frequency remains unaltered in all three cases. Initially all eigenmodes are in damped regime and start to get finite growth rates in presence of energetic particle drive. It is observed that increase in growth rate varies linearly with βEP and steadily with (LnEP/a).