Thermal stability considering the slowing-down process of alpha particles

The effects of the slowing-down process of the energetic ions on the thermal stability of a D-T fusion plasma are investigated comparing two alternative approximations; the instantaneous slowing-down approximation and the multi-group slowing-down approximation on the plasma heating by the energetic ions. Comparison is made on the eigenvalues of the linearized dynamic equations as well as on the numerical integration of the non-linear equations. The proper treatment of the slowing-down process by the multi-group formulation suggests that the slowing-down time delay makes the fusion plasma more stable