Low frequency electromagnetic waves in a multi-ion plasma

Abstract

The dispersion characteristics of low-frequency electromagnetic waves are studied in a plasma containing hydrogen ions and positively and negatively charged oxygen ions and electrons. This composition of the plasma approximates very well the coma of comet Halley where many heavy ions have been observed in appreciable numbers. The excitation of these waves results from the relative motion between the protons and the heavy ions, which are considered unmagnetised and, therefore, may act like a beam. We find that the wave growth increases with increasing heavy ion densities, beam velocities and propagation angles.