Plasma oscillations

Abstract

A comprehensive review is given of the state of knowledge on plasma oscillations in the narrower sense, and of those electronic oscillations which are determined by the internal dynamics of the discharge rather than by the outer circuit. Experimental and theoretical work is reviewed and a new mathematical formulation is given for oscillations in "irrotational" streams. If the electrons and ions originate outside a magnetic field, or if they issue from cathodes where the magnetic field has no normal component, the curl of the total or Schwarzschild momentum will be zero everywhere. In this important case the self-consistent equations of any number of electron or ion streams can be completely formulated in a series of differential equations for certain vector stream-functions; one function for each stream. Comparatively few cases have been discussed so far with the proper boundary conditions. The most important targets for research are pointed out.