Subsonic and supersonic nucleus-acoustic solitary waves in thermally degenerate multi-nucleus plasma systems

Abstract

A new thermally degenerate multi-nucleus plasma system (containing thermally degenerate electron species, non-degenerate warm light nucleus species, and low dense stationary heavy nucleus species) is considered. The basic features of arbitrary amplitude subsonic and supersonic solitary waves associated with thermally degenerate pressure-driven nucleus-acoustic waves in such a plasma system are studied by the pseudo-potential approach. The effects of the stationary heavy nucleus, non- and ultra-relativistically degenerate electron degeneracies, and light nucleus temperature on such arbitrary amplitude subsonic and supersonic solitary waves are also examined. It is found that (i) the presence of the heavy nucleus and Boltzmann distributed electron species supports the existence of subsonic solitary waves and the effects of electron degeneracies and light nucleus temperature reduce the possibility for the formation of these subsonic solitary waves; (ii) the amplitude (width) of these subsonic solitary waves increases (decreases) with the increase in the number density of the heavy nucleus species; (iii) the amplitude of the supersonic solitary waves in the situation of non-relativistically degenerate electron species is much smaller than that of the ultra-relativistically degenerate electron species but is much larger than that of the Boltzmann distributed electron species; (iv) their width in the situation of non-relativistically degenerate electron species is much wider than that of the ultra-relativistically degenerate electron species; and (v) their amplitude (width) decreases (increases) with the increase in the light nucleus temperature. The applications of the results in some degenerate astrophysical plasma systems and non-degenerate space plasma environments are discussed.