Field In Dusty Plasma Research Articles

DPEx-II: a new dusty plasma device capable of producing large sized DC coulomb crystals

The creation of a spatially extended stable DC complex plasma crystal is a big experimental challenge and a topical area of research in the field of dusty plasmas. In this paper we describe a newly built and commissioned dusty plasma experimental (DPEx-II) device at the Institute for Plasma Research. The device can support the formation of large sized Coulomb crystals in a DC glow discharge plasma. The plasma in this L-shaped table-top glass chamber is produced between a circular anode and a long tray shaped cathode. It is characterized with the help of various electrostatic probes over a range of discharge conditions. The dust particles are introduced by a dust dispenser to form a strongly coupled Coulomb crystal in the cathode sheath region. The unique asymmetric electrode configuration minimizes the heating of dust particles and facilitates the formation of crystalline structures with a maximum achievable dimension of 40 cm × 15 cm using this device. A larger crystal has numerous advantages over smaller ones, such as higher structural homogeneity, fewer defects, lower statistical errors due to finite size effects etc. A host of diagnostics tools are provided to characterize the Coulomb crystal. Results of a few initial experiments aimed at demonstrating the technical capabilities of the device and its potential for future dusty plasma research, are reported.

Lower-hybrid turbulence in the near-surface lunar dusty plasmas

The results are presented of the first investigation of linear and nonlinear processes associated with waves which are related to the presence of magnetic fields in dusty plasmas at the Moon. Excitation of lower-hybrid turbulence in dusty plasmas near the lunar surface is studied. It is shown that the lower-hybrid turbulence can be generated wherever the Earth's magnetotail interacts with the near-surface dusty plasmas at the Moon. The electric fields appearing as a consequence of the presence of lower-hybrid turbulence are estimated. They can make a significant contribution to the total electric field above the lunar surface which should be taken into account in the future experimental investigation of electric fields at the Moon.

Guest Editorial Special Issue on Dusty Plasmas

This special Issue focuses on the field of dusty plasmas or also referred to as complex plasmas. Most of the papers were presented at the 8th International Conference on the Physics of Dusty Plasmas (8 ICPDP, Fig. 1 ), which was hosted by Charles University and held in Prague, Czech Republic, on May 20–25, 2017. We would like to join the continuous tradition of special issues of the IEEE Transactions on Plasma Science from April 1994, 2001, 2004, 2007, 2010, 2013, and 2016 associated with the other most important triennial meeting for the community, the Workshop on the Physics of Dusty Plasmas. We believe that these two conferences and papers connected to them reflect the current state of the art and progress in the field.

Dynamics of a magnetic field in dusty plasma

The problem of the expansion of a magnetic field in a complex (e.g., dusty) plasma is considered, with a focus on the effects produced by the independent transport of charged components that does not break plasma quasineutrality. Solutions to a set of nonlinear equations are obtained for different initial and boundary conditions. In particular, it is shown that the field rapidly penetrates into the plasma when the dust is charged negatively and does not penetrate at all when the dust charge is positive.

Nonlinear structure in a current-carrying collisional dusty plasma

A perpendicular ion drift is proposed as a possible mechanism for the generation of magnetic field structures in a highly collisional dusty plasma. The basic dissipation mechanism is assumed to be the dust-neutral momentum exchange, so that plasmas with a small ionization fraction are natural candidates for experiments. The model reduces to a nonlinear partial differential equation for the vector potential. The conditions for linear instability are presented. Possible stationary states are periodic arrangements for the magnetic field, described by a Lienard equation. The fully depleted (ion-dust) case is also considered in detail. Applications of the present work to magnetic field structures in planetary rings, comets, and low-temperature dusty plasma experiments are discussed. A necessary condition for the validity of the model is a sufficiently slow time scale of the generated magnetic fields in dusty plasmas.

Effects of interaction between plasma-flow fields and electrostatic fields in dusty plasmas

Interaction between plasma-flow fields and electrostatic fields is considered as the most appropriate method for describing the characteristic properties of a dusty plasma. This method makes it possible to treat the openness of the dusty plasma systems and to describe the processes of self-organization and change in interaction between dust particles that are caused by the presence of plasma flows, in particular, to describe attraction between the dust particles at large distances, as well as the pairing of identically charged particles and the formation of complicated dusty structures including dusty plasma crystals. Interaction between the plasma-flow fields and electrostatic fields was previously taken into account only when considering particular problems but was not considered as the general characteristic property of the dusty plasma. It is emphasized that the model taking into account the plasma-flow fields and their interaction with the electrostatic fields is the only model that allows simultaneous explanation of all basic parameters characterizing the condensation of the dusty plasma to plasma crystals (coupling constant Γ, interparticle distance rmin, and melting temperature Td) obtained in observations. Attraction between the dust particles at large distances leads to instability similar to gravitational instability, which was erroneously disregarded in previous descriptions of the dust sound. The corresponding critical size is similar to the Jeans radius. As a result of such attraction, dusty systems are structured, and such structuring is similar to known gravitational structuring and can explain the observation of dusty structures in most laboratory experiments on the dusty plasma.

Razvitie fizicheskikh predstavlenii o vzaimodeistvii plazmennykh potokov i elektrostaticheskikh polei v pylevoi plazme

Развитие физических представлений о взаимодействии плазменных потоков и электростатических полей в пылевой плазме, Цытович В.Н.

Spontaneous generation of magnetic fields in astrophysical dusty plasmas

Two novel mechanisms for spontaneous generation of magnetic fields in dusty plasmas are presented. These are a new dust–plasma battery involving the cross product of the gradient of the dust charge density and the electron–ion pressures, as well as a new Weibel-like instability involving ion pressure anisotropy and resistive electron motions. The relevance of the present investigation to magnetic fields in astrophysical objects is discussed.

A class of stationary nonlinear dusty plasma equilibria

It is shown that nonparallel density and temperature gradients can produce magnetic fields in dusty plasmas. Spontaneously created magnetic fields can be maintained if there exists plasma vorticity. In order to understand this phenomena, a self-consistent dusty plasma equilibrium model is constructed by employing a kinetic description and invoking the Hamiltonian approach. Stationary nonlinear dusty plasma equilibria contain specific profiles for the plasma number density, the plasma current, and the magnetic field. The relevance of this investigation to low-temperature laboratory dusty and space plasmas is discussed.

Some remarks on the generation and dissipation of magnetic fields in dusty plasmas

We present a set of balance equations that governs the low-frequency dynamics of partially-ionized dusty magnetoplasmas. We address the generation of magnetic fields caused by ion sheared flows taking into account electron-dust collisions and the magnetic flux problem in protostellar clouds. Our numerical simulations indicate that sheared ion flows may play an important role in the generation of magnetic fields, e.g in protostellar objects. Resistive diffusion seems to be fast enough to allow for a gravitational collapse of protostellar clouds only for the case that a major part of the cloud consists of dust grains. Alternatively, the resistive tearing instability that results in faster magnetic dissipation may be regarded as a mechanism in favour of star formation in self-gravitational clouds.