Dust acoustic solitary waves in a five component cometary plasma with dust charge variation

Abstract

The characteristics of dust acoustic solitary waves (DASWs), described by the Zakharov-Kuznetsov equation, have been studied in a five component cometary plasma. Negatively charged dust, positively charged lighter and heavier ions (described by Maxwellian distributions) and two components of electrons (modelled by kappa distributions with different temperatures and spectral indices) constitute the plasma. The system supports rarefactive solitary waves whose amplitude increases when charge variation on the dust particles is considered. We find that the second, superthermal component of electrons has a strong influence on the characteristics of the DASWs: it's amplitude and width decreases with decreasing temperatures and spectral indices, respectively, of the second component of electrons. The amplitude of the DASW, however, increases with increasing heavier ion densities. Correlation of our results with observations at comet Halley is also indicated.