Abstract:We study the nonlinear propagation of dust-ion acoustic (DIA) solitary waves in an unmagnetized dusty plasma which consists of electrons, both positive and negative ions and negatively charged immobile dust grains. Starting from a set of hydrodynamic equations with the ion thermal pressures and ion kinematic viscosities included, and using a standard reductive perturbation method, the Kadomtsev-Petviashivili Burgers (KPB) equation is derived, which governs the evolution of DIA shocks. A stationary solution of the KPB equation is obtained and its properties are analysed with different plasma number densities, ion temperatures and masses. It is shown that a transition from shocks with negative potential to positive one occurs depending on the negative ion concentration in the plasma and the obliqueness of propagation of DIA waves.PACS Numbers: 52.27.Lw, 52.35.Fp, 52.35.Tc
IntroductionIn the last few decades, numerous investigations have been made on the study of nonlinear waves and structures in low-temperature dusty plasmas as the presence of extremely massive charged dust particles plays a vital role in understanding the electrostatic disturbances in space plasma environments [1][2][3] as well as laboratory plasma devices [4,5]. It has been pointed out that the static charged dust grains can drastically modify the existing response of electrostatic wave spectra in dusty plasmas [4][5][6][7][8][9][10][11]. On the other hand, depending upon whether the dust grains are static or mobile, there appear new types of electrostatic waves including solitary or shock waves in plasmas. Shukla and Silin first theoretically [12] investigated the existence of low-frequency dust-ion acoustic (DIA) waves (with phase speed much smaller than the electron thermal speed and larger than the ion thermal speed) in a three-component dusty plasma. Later, this DIA wave was experimentally observed by Barkan et al using a dusty plasma device [13].The Korteweg-de Vries (KdV) equation, which governs the evolution of solitary waves, was first derived by Washimi and Tanuiti in a normal two-component plasma [14] using a reductive perturbation technique. It has been reported that multi-component plasmas in presence of sufficient amount of negative ions can support both compressive and rarefactive KdV solitons [15]. Furthermore, the properties of DIA solitary waves and shocks as observed in laboratory dusty plasmas are well explained by the modified KdV and KdV-Burgers (KdVB) equations [5,11,16,17].