Dust ion-acoustic solitary structures in non-thermal dusty plasma

Dust ion-acoustic solitary structures have been investigated in an unmagnetized non-thermal plasma consisting of negatively charged dust grains, adiabatic positive ions, and non-thermal electrons. Whenever the non-thermal parameter exceeds a critical value, the present system supports negative potential double layer solution. However, this double layer solution is unable to restrict the occurrence of negative potential solitary waves of the present system. As a result, the occurrence of one type of negative potential solitary wave is restricted by M-c < M < M-D, whereas the second type of solitary wave exists for all M > M-D, where M-c is the lower bound of the Mach number M and M-D(> M-c) is the Mach number corresponding to a negative potential double layer. A finite jump between the amplitudes of negative potential solitary waves at M = M-D -is an element of(1) and M = MD + is an element of(2) has been observed, where 0 < is an element of(1) < M-D - M-c and is an element of(2) > 0. Depending on the analytical theory presented in this paper, a numerical scheme has been provided to find the value of the Mach number at which double layer solution exists, and also the amplitude of that double layer. Although the occurrence of coexistence of solitary structures of both polarities is restricted by M-c < M <= M-max, only negative potential solitary wave still exists for all M > M-max, where M-max is the upper bound of M for the existence of positive potential solitary waves only. Qualitatively different compositional parameter spaces showing the nature of existing solitary structures of the energy integral have been found. These solution spaces are capable of producing new results and physical ideas for the formation of solitary structures whenever one can move the solution spaces through the family of curves parallel to the curve M = M-c.