“Universal” Ballooning Instability

High- n kinetic ballooning instability is obtained where the toroidal coupling, coupling of Alfvén and drift modes, and the correct forms of plasma dispersion functions are retained. This mode is identified as a kinetic description of MHD ballooning mode, and is unstable both in the zero-pressure limit and in the second stability region of MHD analysis. Ballooning mode is universally unstable in toroidal plasmas.