Anirban Bose

Shear-wave Mach cones in a strongly coupled dusty plasma

Shear-wave Mach cones excited in a strongly coupled dusty plasma in the fluid regime are studied using the generalized hydrodynamic model. The Mach cones are excited by a laser beam that is modeled to sweep the three-dimensional dusty plasma with a velocity that is supersonic with respect to the phase velocity of the transverse shear waves. The formation of single Mach cone structures in vorticity maps reveals that they are formed due to shear motion. It is found that an asymmetry in the wake excitation technique gives rise to certain asymmetries in the Mach cone patterns.

Quantum corrections to nonlinear ion acoustic wave with Landau damping

Quantum corrections to nonlinear ion acoustic wave with Landau damping have been computed using Wigner equation approach. The dynamical equation governing the time development of nonlinear ion acoustic wave with semiclassical quantum corrections is shown to have the form of higher KdV equation which has higher order nonlinear terms coming from quantum corrections, with the usual classical and quantum corrected Landau damping integral terms. The conservation of total number of ions is shown from the evolution equation. The decay rate of KdV solitary wave amplitude due to the presence of Landau damping terms has been calculated assuming the Landau damping parameter α1=me/mi to be of the same order of the quantum parameter Q=ℏ2/(24m2cs2L2). The amplitude is shown to decay very slowly with time as determined by the quantum factor Q.

Nonlinear electrostatic structures in the presence of correlations

The nature of nonlinear electrostatic potential distribution in a dusty plasma is investigated in the presence of dust-dust correlations by developing an equilibrium kinetic equation that contains the effects of pair correlations. For a plasma in equilibrium, the role of pair correlations is to give rise to a force in the kinetic equation that is proportional to the dust density gradient. The solutions of such a kinetic equation with pair correlations and Poisson’s equation in the presence of a trapped particle population are obtained in the small-amplitude limit. The electrostatic potential represents a localized solitary wave-like structure with the amplitude and width varying with the correlation parameter.

Lateral and transverse wakes due to moving charged particles

The wake structure of a charged particle moving in a dusty plasma is analyzed for the cases where the charge speed is greater or less than the dust-acoustic speed. In the case of M 1, only lateral wakes are obtained.

A different approach to obtain Mayer's extension to stationary single particle Wigner distribution

It is shown that the stationary collisionless single-particle Wigner equation in one dimension containing quantum corrections at the lowest order is satisfied by a distribution function that is similar in form to the Maxwellian distribution with an effective mass and a generalized potential. The distribution is used to study quantum corrections to electron hole solutions.

Density distribution for a weakly non-ideal non-uniform plasma

An attempt is made to develop an equilibrium kinetic equation for a weakly non-ideal non-uniform plasma utilizing the Bogoliubov–Born–Green–Kirkwood–Yvon hierarchy of equations. The time-independent pair correlation function is shown to be a product of two single-particle non-uniform distribution functions and the binary interaction potential that is taken to be Coulombian. In order to obtain a closed form of kinetic equation, it is necessary to express the first-order corrections to the Vlasov equation arising out of correlations in terms of average plasma potential. The singular nature of the Coulomb potential gives rise to certain divergences that can be removed by the choice of Landau and Debye lengths as the lower and upper limits of the impact parameter. This procedure enables a representation of pairwise interaction potential in terms of average macroscopic potential. The first-order kinetic equation is utilized to obtain a modified Boltzmann distribution that includes the effects of correlations.

Derivation of an equation of pair correlation function from BBGKY hierarchy

An equation of pair correlation function has been derived from the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for an inhomogeneous dusty plasma under certain approximations. This equation may play a useful role to study the inhomogeneous weakly correlated charged particle system.

Plasma equilibrium in a semiclassical plasma due to non-resonant wave particle interactions

A nonresonant perturbative approach has been utilized to probe the modification of the equilibrium plasma distribution function due to plasma interaction with externally launched high-frequency large-amplitude RF waves in the presence of quantum effects. The quantum distribution function from the complete Wigner equation has been obtained for a high-frequency wave with constant amplitude. For waves with weak spatial or temporal modulation, the equilibrium distribution function has been obtained by solving the Wigner equation as an initial or boundary-value problem and retaining only lowest-order quantum effects. In the dipole approximation, a higher order diffusion has been identified in addition to quantum modified ponderomotive and quasilinear diffusion effects. Additional terms of the Wigner equation give the impression of higher order diffusion effects in the system.

Debye-shielding potential in the presence of pair correlations

The first-order kinetic equation of the Bogoliubov–Born–Green–Kirkwood–Yvon hierarchy of equations for an equilibrium inhomogeneous plasma is shown to contain an effective force resulting from pair correlations that depends on the gradient of the average electric field modulus. Such a kinetic equation is utilized to obtain a Boltzmann distribution that includes the effects of correlations. For an electron-ion plasma with stationary ions and finite electron-electron correlations, the nature of the Debye-screening potential is investigated.

Directional Landau damping of wake-field potentials

The wake-field potentials produced by charged particles moving in a plasma are investigated in the presence of finite Landau-damping effects in the wave dispersion relation. In the frame of reference moving with the particle, the phase velocities of the spectrum of waves excited by the moving charge depend on the angle of propagation of the wave vector giving rise to a directional wave-particle resonance condition. As a consequence, the wake structure is seen to decay both along and transverse to the direction of motion of the charged particle.