Deb Kumar Ghosh

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 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.

-Nonextensive Velocity Distribution

The presence of a continuum bound state for the nucleon-nucleon (nn) scattering by a nonlocal potential in which Yamaguchi potential enters as an attractive part is examined. It is well-known that an extra node in the radial wave function is directly related to the existence of a continuum bound state in the scattering spectrum. The extra nodes of the wave functions occur in conjunction with the zeros of the Fredholm determinants associated with the physical and regular wave functions of the radial equation for the nonlocal potential. Here we have observed that the extra nodes also occur in conjunction with the zeros of the transition matrix.