Relativistic ion cyclotron instability driven by Mev α-particles in non-uniform magnetic fields

The harmonic relativistic ion cyclotron instability driven by Mev α-particles in thermal deuterium plasmas confined by non-uniform magnetic fields is studied with gyrokinetic theory. An integral dispersion equation is derived and solved numerically. The results provide clear evidence for the existence of the instability of α-particle cyclotron high harmonics in burning plasmas of one fast and one slow ion species. The characteristics of the modes are found to depend on magnetic non-uniformity parameter and α-particle density rather strongly (author)