New insights on fast ion-acoustic soliton stopbands and extension to dusty plasmas

Large amplitude fast ion-acoustic solitons are revisited in a three-component plasma composed of cold ions, warm (adiabatic) ions, and hot Boltzmann electrons to determine where the limits occur in the ranges of the warm ion-to-electron temperature ratio τ and the charge-to-mass ratio of the cold ions relative to the warm ions μ for the existence of stopbands. The warm (adiabatic) ion limiting curve evolves in a similar fashion for increasing values of τ or decreasing values of μ in supporting the existence of stopbands when the warm ion limiting curve is double-valued in the Mach number over part of a range of cold ion densities, to the disappearance of the stopbands when the warm ion limiting curve is single-valued over the complete range of cold ion densities. The bifurcation of the warm ion limiting curve into an upper and lower branch indicates the transition region in parameter space, which is between the region where stopbands are supported and the region where stopbands do not occur. The stopbands are found to have an infinite extent over the range of cold ion densities in the transition region. The widening (or narrowing) of the stopbands over the range of cold ion densities associated with a kappa (or Cairns) distribution of hot ions in a four-component plasma is found to be much weaker than non-thermal electron effects on the stopbands as reported by Maharaj and Bharuthram [Phys. Plasmas 24, 022305 (2017)].