Uday Narayan Ghosh

Head-on collision of ion acoustic solitary waves in an electron-positron-ion plasma with superthermal electrons

The head-on collision of ion acoustic solitary waves in a three-component unmagnetized plasma with cold ions, Boltzmann distributed positrons, and superthermal electrons is investigated using the extended Poincare–Lighthill–Kuo method. The effects of the ratio of electron temperature to positron temperature, the spectral index, κ, of the electron kappa distribution, and fractional concentration of positron component (p) on the phase shift are studied. It is found that the presence of superthermal electrons play a significant role on the collision of ion acoustic solitary waves.

The effect of q-distributed electrons on the head-on collision of ion acoustic solitary waves

The head-on collision of ion acoustic solitary waves (IASWs) in two component plasma comprising nonextensive distributed electrons is investigated. Two opposite directional Kortewg-de-vries (KdV) equations are derived and the phase shift due to collision is obtained using the extended version of Poincare-Lighthill-Kuo method. Different ranges of nonextensive parameter q are considered and their effects on phase shifts are observed. It is found that the presence of nonextensive distributed electrons plays a significant role on the nature of collision of ion acoustic solitary waves.

Head-on collision of dust acoustic solitary waves in a four-component dusty plasma with nonthermal ions

The head-on collision of dust acoustic solitary waves in a four-component unmagnetized dusty plasma with Boltzmann distributed electrons, nonthermal ions, and negatively charged dust grains as well as positively charged dust grains is investigated using the extended Poincare-Lighthill-Kuo method. The effects of the ratio of electron temperature to ion temperature and the ratio of the positively charged dust grains mass to the negatively charged dust grains mass on the phase shift are studied. It is found that the presence of nonthermal ions plays a significant role on the collision of dust acoustic solitary waves. This study would be useful for investigations of plasma behavior in different regions of space, viz., cometary tails, upper and lower mesosphere, Jupiter’s magnetosphere, etc.

Nonplanar dust-ion acoustic Gardner solitons in a dusty plasma with q-nonextensive electron velocity distribution

The basic features of planar and nonplanar time-dependent dust-ion acoustic Gardner solitary waves have been studied in an unmagnetized dusty plasma system consisting of positively and negatively charged dust, Boltzmann distributed ions and nonextensive q-distributed electrons. The modified Gardner equation is derived by employing the reductive perturbation technique, which is beyond the Korteweg-de Vries (KdV) limit (corresponding to the vanishing of nonlinear coefficient of the KdV equation). It has been observed that the nonextensive q-distribution of electrons has a significant effect on the MG equation and also plays an important role beyond the KdV limit.

Nonplanar Ion Acoustic Solitary Waves in Electron-Positron-Ion Plasma With Warm Ions, and Electron and Positron Following

Cylindrical and spherical modified Korteweg-de Vries equations are derived for ion-acoustic solitary waves (IASWs) in an unmagnetized, collisionless electron-positron-ion plasma consisting of warm ion fluid and q-nonextensive distributed electrons and positrons by using standard reductive perturbation method. The effects of nonplanar geometry, nonextensivity of electrons and positrons, and other plasma parameters on nonlinear dynamics of cylindrical and spherical IASWs are studied numerically. Numerical results indicate that the amplitude of the soliton is large in spherical geometry in comparison with cylindrical geometry, and both the electron and positron nonextensive parameter has a significant effect on the structure of the nonplanar IASWs.

q

The head-on collisions between nonplanar dust-ion acoustic solitary waves are dealt with by an extended version of Poincare-Lighthill-Kuo perturbation method, for a plasma having stationary dust grains, inertial ions, and nonextensive electrons. The nonplanar geometry modified analytical phase-shift after a head-on collision is derived. It is found that as the nonextensive character of the electrons becomes important, the phase-shift decreases monotonically before levelling-off at a constant value. This leads us to think that nonextensivity may have a stabilizing effect on the phase-shift.

-Nonextensive Velocity Distribution

The properties of non-planar (cylindrical and spherical) ion acoustic solitary waves (IASWs) in an unmagnetized collisionless electron-positron-ion (e-p-i) plasma, whose constituents are inertial ions and superthermal/non-Maxwellian electrons and positrons (represented by the kappa (κ) distribution), are investigated by deriving the modified Gardner (MG) equation. The well-known reductive perturbation method is employed to derive the MG equation. The basic features of non-planar IA Gardner solitons (GSs) are discussed. It is seen that the properties of non-planar IAGSs (positive and negative) differ significantly as the value of spectral index kappa changes.

Interaction of dust-ion acoustic solitary waves in nonplanar geometry with electrons featuring Tsallis distribution

The ion acoustic solitary waves are investigated in an unmagnetized electron-ion quantum plasmas. The one dimensional quantum hydrodynamic model is used to study small as well as arbitrary amplitude ion acoustic waves in quantum plasmas. It is shown that ion temperature plays a critical role in the dynamics of quantum electron ion plasma, especially for arbitrary amplitude nonlinear waves. In the small amplitude region Korteweg-de Vries equation describes the solitonic nature of the waves. However, for arbitrary amplitude waves, in the fully nonlinear regime, the system exhibits possible existence of quasi-periodic behavior for small values of ion temperature.

NON-PLANAR ION ACOUSTIC GARDNER SOLITONS IN ELECTRON–POSITRON–ION PLASMA WITH SUPERTHERMAL ELECTRONS AND POSITRONS

Dust ion-acoustic traveling waves are studied in a magnetized dusty plasma in presence of static dust and non-extensive distributed electrons in the framework of Zakharov-Kuznesstov-Burgers (ZKB) equation. System of coupled nonlinear ordinary differential equations is derived from ZKB equation, and equilibrium points are obtained. Nonlinear wave phenomena are studied numerically using fourth order Runge-Kutta method. The change from unstable to stable solution and consequently to asymptotic stable of dust ion acoustic traveling waves is studied through dynamical system approach. It is found that some dramatical features emerge when the non-extensive parameter and the dust concentration parameters are varied. Behavior of the solution of the system changes from unstable to stable and stable to asymptotic stable depending on the value of the non-extensive parameter. It is also observed that when the dust concentration is increased the solution pattern is changed from oscillatory shocks to periodic solution. Thus, non-extensive and dust concentration parameters play crucial roles in determining the nature of the stability behavior of the system. Thus, the non-extensive parameter and the dust concentration parameters can be treated as bifurcation parameters.

Quasi-periodic behavior of ion acoustic solitary waves in electron-ion quantum plasma

Recently Gun Li et al. discussed “Effects of damping solitary wave in a viscosity bounded plasma” [Phys. Plasmas 21, 022118 (2014)]. The paper contains some serious errors which have been pointed out in this Comment.