Stimulation of electron Bernstein modes by perpendicular ion beams

Abstract

This investigation studies the characteristics of electron cyclotron harmonic waves generated by almost monoenergetic perpendicular ion beams. Its motivation is twofold: (1) the new type of free energy source, beams made up of protons, alpha particles, and multiply ionized carbon, nytrogen or oxygen ions, has recently been observed in the geoplasma, and (2) the classical mechanism associated with the stimulation of these electrostatic modes is unable to explain some of their observed features, namely the fine structure sometimes seen in the emission bands and the occurrence of multiple harmonics with the higher branches lying above the upper hybrid frequency. The appropriate dispersion equation supports the developed analysis and determines the properties of this new excitation mechanism. Its characteristics contribute to overcome difficulties encountered by the standard paradigm in the interpretation of several types of electron Bernstein emissions.