A new interpretation of long period micropulsations

A new theory is proposed to account for certain types of long period micropulsations. An instability associated with a field-aligned column of hot plasma is demonstrated; the energy of the oscillations results from the free energy associated with the inhomogeneous plasma. A dispersion relation is derived that has the complex frequency as an eigenvalue. The dispersion relation indicates that there are only a finite number of allowed frequencies and growth rates and these are consistent with observed micropulsation frequencies. The principal shortcoming is that the theory calls for a transverse scale size of the field-aligned column that is about a factor of 10 smaller than indicated by observation. If the requirement for small scale size can be overcome, the theory can account for the observed micropulsation characteristics.