Potential feedback control of drift-cyclotron instability

Potential feedback control applied to drift-cyclotron instabilities is discussed, along with stabilization by other feedback modes. Removal of the points of intersection of the drift branch and ion cyclotron branch is not always a necessary condition for stabilization (e.g., density feedback). Fluid-like modes exemplifying reactive-type microinstability constitute a problem. Conditions for removal of points of intersection of the branches, fluid-like modes with the field-aligned component of the wave vector finite, and dissipative instability resulting from resonance between ions and waves are examined. The study is restricted to application of frequency-independent potential feedback with 180 deg phase shift.