S. N. Paul

Surface wave propagation in a magnetized dusty plasma with charge fluctuation

Propagation of a surface wave in a semi-infinite magnetized dusty plasma is analyzed by taking into account the dust-charge fluctuation and assuming that the magnetic field is weak. The dispersion relation is deduced and analyzed to show the existence of a modified low frequency mode, which reduces to the result obtained earlier in the zero fluctuation limit. The two different cases of electrostatic and electromagnetic mode are discussed separately. Last, numerical estimates of the attenuation coefficient as a function of the frequency for its various range of values have been done and are displayed graphically.

A novel ditopic chemosensor for cadmium and fluoride and its possible application as a pH sensor

A urea-based BPC [1,5-bis(perfluorophenyl)carbonohydrazide] molecule with four acidic NH protons has been synthesized by a facile synthetic process. The molecule was found to be a ditopic chemosensor for Cd2+ and F− ions. BPC was synthesized from low-cost starting materials, dinitrophenyl hydrazine and triphosgene. The host–guest interactions between the ions (Cd2+ and F−) were not only confirmed by convenient spectroscopic techniques such as UV-Vis, PL, 1H-NMR, FT-IR, and cyclic voltammetry but also through modern DFT, the results of which were in good agreement with the experimental results. In vitro studies in human cancer cells (HeLa cells) were successfully performed with BPC and Cd2+ using fluorescence microscopy. The reversible UV-Vis response for BPC with F−, OH− and H+ mimics multiple logic functions and can be used for several complex electronic circuits based on logic operations. The pH sensor (BPC) can be further interfaced with suitable circuitry interfaced with appropriate programming for ease of access and enhancement of its practical applications.

Stimulated Brillouin scattering in a magnetized dusty plasma with charge fluctuation

Stimulated Brillouin scattering of an electromagnetic wave is investigated analytically in a magnetized dusty plasma. Variation of growth rates of the scattered ion-acoustic wave and the electromagnetic wave have been analyzed with respect to the concentration of dust particles by taking account dust charge fluctuation.

Wave Propagation in a Magnetized Dusty Plasma

The properties of waves propagating in amagnetized dusty plasma are analyzed for both high andlow values of the ion-cyclotron frequency. The electronsare considered to be hot. The dispersion relation for a wave propagating through the dusty plasmaat an arbitrary angle with the external magnetic fieldis derived. This rectifies some errors in the earliertreatment of Cramer and Vladimirov (1996). Effects of the presence of the dust on thecharacteristics of wave propagation arediscussed.

Effects of boundary and electron inertia on the ion acoustic wave in a plasma: a pseudopotential approach

A pseudopotential approach is used to analyse the propagation of ion-acoustic waves in a plasma bounded by a cylindrical domain. The effect of the finite geometry is displayed both analytically and numerically. The phase velocity of the wave is determined and its variation is studied with respect to the plasma parameters. It is observed that the pseudopotential shows a wide variation of shape due to the imposition of a finite boundary condition. It is shown that if the other parameters are kept within a certain range of values, then the trapping of particles is favoured when the presence of the boundary is taken into account.

Effect of electron inertia on double layers in a relativistic hot plasma

The ion-acoustic double layer in a relativistic hot plasma is studied by considering the effect of electron inertia. The critical region is analysed with the help of a combination of the KdV and mKdV equations obtained via a reductive perturbation technique. The profiles of the double layer are explicitly obtained for various values of the plasma parameters and of the electron-ion mass ratio.

Effect of streaming electrons on the propagation of electromagnetic waves in a magnetised relativistic plasma

Expressions for the first- and third-order dispersion relations have been derived for circularly polarised waves in a magnetised relativistic plasma containing electron streams. From the first-order dispersion relations it is seen that the waves are split into three parts, one of which is reflected causing the formation of standing waves in the streaming plasma. From the third-order dispersion relations, the expression for the shifts of wave number has been obtained. It is observed that the streaming of electrons has a significant contribution to the wave-number shift of the electromagnetic waves.

On the ion-acoustic soliton in a relativistic beam ion plasma system

The authors analyzed the formation of ion-acoustic solitons in a beam-plasma system, where both the beam and the ion were considered to be relativistic. The system is assumed to be nonisothermal. Both lower- and higher-order computations are performed, and the change of the wave profile is discussed, both in the lower and higher order. It is observed that both the amplitude and the width of the soliton change significantly in the presence of the relativistic effect and ion beam. The variations of these quantities with respect to v/sub 0//c, the ion-beam population, and the nonisothermality of the plasma are depicted graphically and compared with other results. >

Higher order contribution to the propagation characteristics of low frequency transverse waves in a dusty plasma

Characteristic features of low frequency transverse wave propagating in a magnetised dusty plasma have been analysed considering the effect of dust-charge fluctuation. The distinctive behaviours of both the left circularly polarised and right circularly polarised waves have been exhibited through the analysis of linear and non-linear dispersion relations. The phase velocity, group velocity, and group travel time for the waves have been obtained and their propagation characteristics have been shown graphically with the variations of wave frequency, dust density and amplitude of the wave. The change in non-linear wave number shift and Faraday rotation angle have also been exhibited with respect to the plasma parameters. It is observed that the effects of dust particles are significant only when the higher order contributions are considered. This may be referred to as the ‘dust regime’ in plasma.

On the generation of magnetic fields due to ponderomotive forces in astrophysical plasmas

The generation of magnetic fields due to ponderomotive forces in astrophysical plasma consisting of electrons, ions and positrons is investigated theoretically. It is seen that collisional or non-collisional interactions (between electromagnetic waves and plasma particles) via ponderomotive forces in an inhomogeneous plasma can excite a magnetic field. The growth rate of the magnetic field is illustrated graphically for different values of the temperature and concentration of positrons in the plasma.