Coexistence of Dust Ion Acoustic Double Layers in Negatively Charged Dusty Plasma with Superthermal Electrons

Abstract Motivated by observations of double layers (DLs) in the Martian magnetosheath plasma, we theoretically investigate the existence of DLs and their coexistence in a dusty plasma system. The considered negatively charged dusty plasma system consists of warm positive ions, warm negatively charged dust grains, and superthermal electrons. To study large amplitude nonlinear structures, the Sagdeev pseudopotential method is used, and the corresponding energy integral equation is derived. Numerical analysis reveals that the plasma system supports both compressive and rarefactive solitary waves as well as DLs. Interestingly, the plasma system exhibits not only the coexistence of positive and negative polarity solitons but also the coexistence of DLs under appropriate parametric conditions. The monopolar positive and negative electric field structures associated with the predicted DLs are qualitatively similar to the electric field signatures of DLs reported in observations of the Martian magnetosheath. In addition, the model predicts positive and negative bipolar electric field pulses associated with solitary waves, and the corresponding phase-space trajectories have also been examined. The results show that the formation and characteristics of DLs are highly sensitive to key plasma parameters, including the dust charge number, Mach number, superthermal parameter ( k ) , and dust density. The potential structures corresponding to the coexistence of DLs are illustrated through the associated Sagdeev pseudopotential profiles. These findings are directly relevant to dusty plasma environments in the Earth’s ionosphere and provide deeper insight into the dynamics of large-amplitude nonlinear structures and their role in energy transport and dissipation in dusty plasmas.