Many-particle charged-particle plasma simulations using spatial meshes for the electromagnetic field solutions, particle-in-cell (PIC) merged with Monte Carlo collision (MCC) calculations, are coming into wide use for application to partially ionized gases. The author emphasizes the development of PIC computer experiments since the 1950s starting with one-dimensional (1-D) charged-sheet models, the addition of the mesh, and fast direct Poisson equation solvers for 2-D and 3-D. Details are provided for adding the collisions between the charged particles and neutral atoms. The result is many-particle simulations with many of the features met in low-temperature collision plasmas; for example, with applications to plasma-assisted materials processing, but also related to warmer plasmas at the edges of magnetized fusion plasmas. >

Particle-in-Cell Charged Particle Simulations, plus Monte Carlo Collisions with Neutral Atoms, PIC-MCC

Complex (dusty) plasmas: current status, open issues, perspectives

1 The Equations of Gas Dynamics 2 Magnetoplasma Dynamics 3 Waves in Magnetoplasmas 4 Magnetoplasma Stability 5 Transport in Magnetoplasmas 6 Extensions of Theory Bibliography Index

Physics of plasmas

Complex (dusty) plasmas are composed of a weakly ionized gas and charged microparticles and represent the plasma state of soft matter. Complex plasmas have several remarkable features: Dynamical time scales associated with microparticles are ``stretched'' to tens of milliseconds, yet the microparticles themselves can be easily visualized individually. Furthermore, since the background gas is dilute, the particle dynamics in strongly coupled complex plasmas is virtually undamped, which provides a direct analogy to regular liquids and solids in terms of the atomistic dynamics. Finally, complex plasmas can be easily manipulated in different ways---also at the level of individual particles. Altogether, this gives us a unique opportunity to go beyond the limits of continuous media and study---at the kinetic level---various generic processes occurring in liquids or solids, in regimes ranging from the onset of cooperative phenomena to large strongly coupled systems. In the first part of the review some of the basic and new physics are highlighted which complex plasmas enable us to study, and in the second (major) part strong coupling phenomena in an interdisciplinary context are examined. The connections with complex fluids are emphasized and a number of generic liquid and solid-state issues are addressed. In summary, application oriented research is discussed.

Complex plasmas: An interdisciplinary research field

Dusty plasmas are ubiquitous in low-temperature laboratory discharges as well as in the near-earth environment, planetary rings, and interstellar spaces. In this paper, updated knowledge of fundamentals of collective dust-plasma interactions and several novel phenomena are presented that have been observed in laboratories and in space dusty plasmas. Mechanisms that are responsible for the charging of dust grains are discussed, and the fact that the dust charge perturbation is a new dynamical variable in a dusty plasma. The underlying physics of different forces that act on a charged dust grain is reviewed. In dusty plasmas, there are new attractive forces (e.g., due to wakefield and ion focusing effects and dipole-dipole interactions between unevenly charged dust rods). Furthermore, in the presence of an ensemble of charged dust grains, there are collective dust-plasma interactions featuring new waves (e.g., the dust acoustic wave, the dust ion-acoustic wave, the dust lattice wave, etc.), new instabilities, and coherent nonlinear structures (dust acoustic and dust ion-acoustic shocks, dust voids, and dust vortices), which are also discussed. Theoretical models for numerous collective dust-plasma interactions are compared with existing observations from laboratories and space environments.

Colloquium : Fundamentals of dust-plasma interactions

Regelmasige kristallartige Anordnungen geladener Teilchen sind von hohem asthetischen Reiz und haben in der Physik Bedeutung als Modellsysteme, an denen sich fest-flussig-Phasenubergange in zwei und drei Dimensionen studieren lassen. Die Erzeugung solcher Kristalle mit hochgeladenen Partikeln von Mikrometergrose in Hochfrequenzentladungen ist ein Phanomen, das erst seit zwei Jahren bekannt ist. In diesem System, dem Plasmakristall, kann man die Struktur und die Teilchendynamik unmittelbar mit dem blosen Auge und auch quantitativ mit der Videokamera untersuchen. Wir stellen hier einen Phasenubergang des Plasmakristalls vor, der durch eine Zunahme der kinetischen Energie der Teilchen getrieben wird. Eine unerwartete hexagonal ausgerichtete Struktur last sich mit Eigenschaften der Plasmafalle erklaren.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/phbl.19960521208

Plasmakristall und Plasmafalle

Difference control schemes for controlling unstable fixed points become important if the exact position of the fixed point is unavailable or moving due to drifting parameters. We propose a memory difference control method for stabilization of a priori unknown unstable fixed points by introducing a memory term. If the amplitude of the control applied in the previous time step is added to the present control signal, fixed points with arbitrary Lyapunov numbers can be controlled. This method is also extended to compensate arbitrary time steps of measurement delay. We show that our method stabilizes orbits of the Chua circuit where ordinary difference control fails.

Memory difference control of unknown unstable fixed points: Drifting parameter conditions and delayed measurement

Experiments on three-dimensional (3D) spherical arrangements of charged dust particles in a plasma confinement (Yukawa balls) are presented. The plasma trap provides a 3D isotropic harmonic confinement in which a small number of dust particles, N < 100, are trapped. The particle arrangement is recorded using stereoscopic imaging. Transitions between different configurations of Yukawa balls are observed that allow us to determine the energy landscape in such a finite cluster. The experiments have been compared to molecular dynamics (MD) simulations with very good agreement. (Some figures in this article are in colour only in the electronic version)

Energy landscape in 3D finite dust clusters derived from shell transitions

Plasma drifts deduced from resonance cone asymmetries: II. Evaluation of COREX data

To study turbulence, high spatial and temporal resolution are required. In experiments, plasma diagnostics are characterized by low spatial and high temporal resolution. An adapted super-resolution algorithm is proposed to improve the spatial resolution by using temporal information. The performance of the super-resolution algorithm is compared with simple interpolation techniques. By means of synthetic data its performance is benchmarked.

Alexander Piel

Papers

Plasmakristall und Plasmafalle

Memory difference control of unknown unstable fixed points: Drifting parameter conditions and delayed measurement

Energy landscape in 3D finite dust clusters derived from shell transitions

Plasma drifts deduced from resonance cone asymmetries: II. Evaluation of COREX data

A super-resolution method for spatio-temporal plasma diagnostics