Effect of dust charging and trapped electrons on nonlinear solitary structures in an inhomogeneous magnetized plasma

Abstract

Main concerns of the present article are to investigate the effects of dust charging and trapped electrons on the solitary structures evolved in an inhomogeneous magnetized plasma. Such a plasma is found to support two types of waves, namely, fast wave and slow wave. Slow wave propagates in the plasma only when the wave propagation angle θ satisfies the condition θ≥tan-1{(1+2σ)-[(ndlh(γ1-1))/(1+ndlhγ1)]-v0u0}, where v0(u0) is the z- (x-) component of ion drift velocity, σ = Ti/Teff, ndlh = nd0/(nel0 + neh0), and γ1=-1Φi0[1-Φi01+σ(1-Φi0)] together with Ti as ion temperature, nel0(neh0) as the density of trapped (isothermal) electrons, Φi0 as the dust grain (density nd0) surface potential relative to zero plasma potential, and Teff=(nelo+neho)TelTeh/(neloTeh+nehoTel), where Tel(Teh) is the temperature of trapped (isothermal) electrons. Both the waves evolve in the form of density hill type structures in the plasma, confirming that these solitary structures are compressive in nature. These structures are found to attain higher amplitude when the charge on the dust grains is fluctuated (in comparison with the case of fixed charge) and also when the dust grains and trapped electrons are more in number; the same is the case with higher temperature of ions and electrons. Slow solitary structures show weak dependence on the dust concentration. Both types of structures are found to become narrower under the application of stronger magnetic field. With regard to the charging of dust grains, it is observed that the charge gets reduced for the higher trapped electron density and temperature of ions and electrons, and dust charging shows weak dependence on the ion temperature.

Low-frequency shock waves in a magnetized superthermal dusty plasma

“…On the other hand, since the width of shock structures is directly proportional to the dispersion coefficient, the increase in strength of magnetic field tends to decrease the width of shocks structures and makes them narrower. Similar kind of behavior was observed by Kumar et al [44]. Figure 8 illustrates the variation of shock structures with magnetic field in 3D.…”

“…The obliquely propagating ion-acoustic (IA) solitons in a magnetized and weakly relativistic warm plasma have been investigated by deriving KdV equation and it was inferred that the soliton energy is lowered by stronger magnetic field and the solitons become narrower [41]. Furthermore, the effect of ion temperature and dust charging on characteristics of ion-acoustic (IA) solitons in a magnetized inhomogenous plasma has been reported by Malik [43] and Kumar et al [44] respectively. The propagation properties of compressive solitons were analyzed by Malik and Malik [47] in a dusty plasma comprising of electrons, positrons and dust grains of either positive or negative charge.…”

“…Since most of the space and astrophysical plasmas are permeated by magnetic field, the effect of external magnetic field on electrostatic solitary waves in different kinds of plasma environments has been studied by various authors [41][42][43][44][45][46][47][48][49][50][51][52][53]. The obliquely propagating ion-acoustic (IA) solitons in a magnetized and weakly relativistic warm plasma have been investigated by deriving KdV equation and it was inferred that the soliton energy is lowered by stronger magnetic field and the solitons become narrower [41].…”

Effect of dust on tilted electrostatic resistive instability in a Hall thruster

“…It is found that in the previous studies, dust particles have been neglected by the researchers, which become important plasma species in the Hall thrusters due to the erosion of the wall of the chamber and sputtering [22,23]. In general, it is found that current carried by the highly mobile electrons plays the important role in dust charging, and as a result, the dust particles are negatively charged in the plasma [24][25][26][27][28][29]. The & Hitendra K. Malik hkmalik@hotmail.com negatively charged dust particles will hinder the movement of ions and, hence, alter the thrust and efficiency of the thruster.…”

The width of the solitary wave in dusty plasma

“…Such a difference causes different dynamics for these two type of plasmas, including shocks and solitary waves. For example, the formation and excitation of nonlinear solitary waves in inhomogeneous magnetized plasmas having negative ions have been studied in Malik & Kawata (2007), Malik & Stroth (2008), Singh & Malik (2008) and the nonlinear solitary waves in plasmas including (impurity) dust particles in (Kumar & Malik 2011; Kumar, Malik & Singh 2012; Malik & Malik 2014). Also, the difference is important from another aspect, that is, dust particles differ from negative ions in that their charge is not a fixed quantity and therefore, this can also cause different dynamics.…”