MPE - Plasmakristall Publications 1998

1998

Authors

Amin MR. Morfill GE. Shukla PK.

Title

MODULATIONAL INSTABILITY OF DUST-ACOUSTIC AND DUST-ION-ACOUSTIC WAVES

Source

Physical Review A. 58(5 Part B):6517-6523, 1998 Nov.

Abstract

Using the standard reductive perturbation technique, a nonlinear Schrodinger equation is derived to study the modulational instability of finite amplitude dust-acoustic (DA) and dust-ion-acoustic (DIA) waves against oblique perturbations (with respect to the propagation direction of the carrier waves) in an unmagnetized dusty plasma. It is shown that both the DA and DIA waves are modulationally unstable. Possible stationary states of the wave packets can appear as envelope solitons. [S1063-651X(98)06111-X]. [References: 20]

Authors

Goree JA. Morfill G. Tsytovich VN.

Title

EXCITATION OF COLLECTIVE PLASMA MODES DURING COLLISIONS BETWEEN DUST GRAINS AND THE FORMATION OF DUST PLASMA CRYSTALS

Source

Plasma Physics Reports. 24(6):490-497, 1998 Jun.

Abstract

Dust plasma crystals have recently been produced in experiments in a number of laboratories. For dust crystallization to occur, there should exist an efficient mechanism for the cooling of the dust plasma component. It is shown that the excitation of collective plasma modes during collisions between the grains may serve as the required cooling mechanism. The excitation of dust sound waves is found to be most efficient. It is shown that the cooling of dust grains via the excitation of collective plasma modes can be even more efficient than that due to collisions with neutral particles, which was previously considered to be the only mechanism for cooling of the dust plasma component. At present, the first experiments are being carried out to study collisions between individual dust grains. High efficiency of the excitation of plasma modes caused by collisions between dust grains is attributed to the coherent displacement of the plasma particles that shield the grains. It is shown that the excitation efficiency is proportional to the fourth power of the charge of the dust grains and to a large power of their relative velocity, and is independent of their mass. The results obtained can be checked in experiments studying how the binary collisions between dust grains and the pressure of the neutral component influence the dust crystallization. [References: 17]

Authors

Amin MR. Morfill GE. Shukla PK.

Title

AMPLITUDE MODULATION OF DUST-LATTICE WAVES IN A PLASMA CRYSTAL

Source

Physics of Plasmas. 5(7):2578-2581, 1998 Jul.

Abstract

It is found that the nonlinear dynamics of amplitude-modulated dispersive dust lattice waves (DLW) is governed by a nonlinear Schrodinger equation. The latter exhibits that a constant amplitude carrier dust lattice wave is modulationally stable, and that the modulated DLW packet propagates in the form of either an envelope dark soliton or an envelope shock. The relevance of our theoretical investigation to simulation studies as well as to a laboratory dusty plasma experiment is pointed out. (C) 1998 American Institute of Physics. [S1070-664X(98)03207-8] [References: 16]

Authors

Amin MR. Morfill GE. Shukla PK.

Title

Modulational instability of dust-lattice waves in a plasma crystal

Source

Physica Scripta. 58(6):628-631, 1998 Dec.

Abstract

A nonlinear Schrodinger equation for the propagation of a dust-lattice wave in a one-dimensional chain of a plasma crystal is derived by using the Krylov-Bogoliubov-Mitropolsky (KBM) perturbation technique. The resulting equation is then analyzed to obtain a nonlinear dispersion relation for the wave envelope. It has been found that the dust-lattice wave is modulationally unstable for long wavelength perturbations and the modulationally unstable wave propagates as an envelope soliton. The importance of this investigation in present-day laboratory experiments for dust-plasma crystallization is pointed out. [References: 18]

Authors

Shukla PK. Amin MR. Morfill G.

Title

IONIZATION INSTABILITY OF MAGNETIZED DUSTY GASES

Source

Physica Scripta. T75:253-255, 1998.

Abstract

The ionization instability of a magnetized dusty plasma in which the neutral gas is ionized by a constant influx of energetic electrons is investigated. We have employed a multi-fluid dusty plasma model to derive dispersion relations for electrostatic dusty plasma waves in the presence of various drags (viz. frictional drag on the dust grains exerted by the neutral atoms, ion losses, ion viscosity, collisions of the ions with the neutrals, and ion losses to the walls or to the dust grains) as well as a source term which accounts for the creation of new ions through ionization of the neutral gas. The dispersion relations are analysed to demonstrate the ionization instability of long wavelength (with respect to the ion and dust gyroradii) and intermediate wavelength [shorter (longer) than the dust (ion) gyroradius] electrostatic fluctuations. The relevance of our investigation to low-temperature astrophysical and laboratory plasmas is pointed out. [References: 9]