Alpha-Particle Effects on Magnetohydrodynamic Stability in the Engineering Test Reactor Tokamak

Estimates based on the proposed parameters for a long-pulse ignition tokamak device, the Engineering Test Reactor, indicate that it is likely that alpha particles will resonantly destabilize high toroidal mode number magnetohydrodynamic ballooning modes, as well as low mode number global types of Alfvén modes, which could be problematic for loss of fusion power. Also, nonresonant enhancement of stability by energetic alpha particles, for the purpose of access into the high-beta second regime of stability, appears to be unlikely for such a device.