arXiv subjects

P. K. Shukla

Publications and source records attributed to P. K. Shukla.

114 records · Page 7Linked to original sources

arXiv2004

Nonlinear model for magnetosonic shocklets in plasmas

Exact nonlinear equations for magnetosonic shocklets in a uniform hot magnetoplasma are derived by using the nonlinear magnetohydrodynamic equations. Analytic as well as numerical solutions of the nonlinear equations are presented. Shock-like structures of the ion fluid velocity and magnetic field (or the plasma density) perturbations are obtained. The results may have relevance to the understanding of fast magnetosonic shocklets that have been recently observed by onboard instruments of the Cluster spacecraft at the Earth's bow shock.

physics.plasm-ph↗

arXiv2004

Nonlinear modulation of transverse dust lattice waves in complex plasma crystals

The occurrence of the modulational instability (MI) in transverse dust lattice waves propagating in a one-dimensional dusty plasma crystal is investigated. The amplitude modulation mechanism, which is related to the intrinsic nonlinearity of the sheath electric field, is shown to destabilize the carrier wave under certain conditions, possibly leading to the formation of localized envelope excitations. Explicit expressions for the instability growth rate and threshold are presented and discussed.

cond-mat.soft↗

arXiv2002

Envelope Solitons of Nonlinear Schrodinger Equation with an Anti-cubic Nonlinearity

On the basis of a recently-proposed method to find solitary solutions of generalized nonlinear Schrodinger equations [1]-[3], the existence of an envelope solitonlike solutions of a nonlinear Schrodinger equation containing an anti-cubic nonlinearity (|Psi|^{-4} Psi) plus a "regular" nonlinear part is investigated. In particular, in case the regular nonlinear part consists of a sum of a cubic and a quintic nonlinearities (i.e. q_1 |Psi|^2 Psi + q_2 |Psi|^4 Psi), an upper-shifted bright envelope solitonlike solution is explicitly found.

nlin.PS↗

arXiv2002

Landau damping of partially incoherent Langmuir waves

It is shown that partial incoherence, in the form of stochastic phase noise, of a Langmuir wave in an unmagnetized plasma gives rise to a Landau-type damping. Starting from the Zakharov equations, which describe the nonlinear interaction between Langmuir and ion-acoustic waves, a kinetic equation is derived for the plasmons by introducing the Wigner-Moyal transform of the complex Langmuir wave field. This equation is then used to analyze the stability properties of small perturbations on a stationary solution consisting of a constant amplitude wave with stochastic phase noise. The concomitant dispersion relation exhibits the phenomenon of Landau-like damping. However, this damping differs from the classical Landau damping in which a Langmuir wave, interacting with the plasma electrons, loses energy. In the present process, the damping is non-dissipative and is caused by the resonant interaction between an instantaneously-produced disturbance, due to the parametric interactions, and a partially incoherent Langmuir wave, which can be considered as a quasi-particle composed of an ensemble of partially incoherent plasmons.

nlin.CD↗

arXiv2002

Envelope solitons induced by high-order effects of light-plasma interaction

The nonlinear coupling between the light beams and non-resonant ion density perturbations in a plasma is considered, taking into account the relativistic particle mass increase and the light beam ponderomotive force. A pair of equations comprising a nonlinear Schrodinger equation for the light beams and a driven (by the light beam pressure) ion-acoustic wave response is derived. It is shown that the stationary solutions of the nonlinear equations can be represented in the form of a bright and dark/gray soliton for one-dimensional problem. We have also present a numerical analysis which shows that our bright soliton solutions are stable exclusively for the values of the parameters compatible with of our theory.

nlin.PS↗

arXiv1998

Comment on "Ponderomotive force due to neutrinos"

The derivation of the ponderomotive force due to neutrinos by Hardy and Melrose, Phys.Rev.D v.54, p.6491 (1996) is based on a flawed analysis of the ponderomotive force concept. Their conclusions also contain an erroneous physical assumption related to the neutrino emission in supernovae. A correct analysis shows the importance of the ponderomotive force due to neutrinos in type II supernovae explosions.

physics.plasm-ph↗