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

There are many processes that can transport gas from the galaxies to their environment and enrich the environment in this way with metals These metal enrichment processes have a large influence on the evolution of both the galaxies and their environment Various processes can contribute to the gas transfer: ram-pressure stripping, galactic winds, AGN outflows, galaxy-galaxy interactions and others We review their observational evidence, corresponding simulations, their efficiencies, and their time scales as far as they are known to date It seems that all processes can contribute to the enrichment There is not a single process that always dominates the enrichment, because the efficiencies of the processes vary strongly with galaxy and environmental properties

Metal Enrichment Processes

The energy distribution of ballistic electrons in a dc/rf hybrid parallel-plate capacitively coupled plasma reactor was measured. Ballistic electrons originated as secondaries produced by ion and electron bombardment of the electrodes. The energy distribution of ballistic electrons peaked at the value of the negative bias applied to the dc electrode. As that bias became more negative, the ballistic electron current on the rf substrate electrode increased dramatically. The ion current on the dc electrode also increased.

Diagnostics of ballistic electrons in a dc/rf hybrid capacitively coupled discharge

Space plasmas possessing non-Maxwellian particle distribution functions with an enhanced high-energy tail and shoulder in the profile of distribution function take an important role to the wave particle interaction. In the present paper Landau damping of electron plasma (Langmuir) waves and ion-acoustic waves in a hot, isotropic, unmagnetized plasma is studied with the generalized (r,q) distribution function. The results show that for the Langmuir oscillations Landau damping becomes severe as the spectral index r or q reduces. However, for the ion-acoustic waves Landau damping is more sensitive to the ion temperature than the spectral indices.

Landau damping in space plasmas with generalized (r,q) distribution function

There are many processes that can transport gas from the galaxies to their environment and enrich the environment in this way with metals. These metal enrichment processes have a large influence on the evolution of both the galaxies and their environment. Various processes can contribute to the gas transfer: ram-pressure stripping, galactic winds, AGN outflows, galaxy-galaxy interactions and others. We review their observational evidence, corresponding simulations, their efficiencies, and their time scales as far as they are known to date. It seems that all processes can contribute to the enrichment. There is not a single process that always dominates the enrichment, because the efficiencies of the processes vary strongly with galaxy and environmental properties.

Metal enrichment processes

Increased Landau damping of electrostatic waves in the presence of low density suprathermal electron populations is examined. An electrostatic dispersion analysis is compared directly with one-dimensional particle-in-cell simulations of the Landau damping rates. An analytic damping rate formula is presented that is in good agreement with numerical solutions of the dispersion equation over a range of parameters.

Enhanced Landau damping of finite amplitude electrostatic waves in the presence of suprathermal electron tails

A spatially independent beam stability model [W. K. Rose et al., Astrophys. J. 280, 550 (1984)] is compared with one-dimensional particle-in-cell (PIC) simulations. The model uses rate equations to evaluate the coupling of longitudinal waves created by beam-plasma instabilities. Equilibrium solutions of the stability model are examined and wave energies from the model are compared with PIC simulations. The PIC simulations enable the stability model to be benchmarked and to explore the temporal evolution of the background plasma electron energy distribution, a capability not presently treated in the stability model. The generation of hot plasma electron tails is examined in the PIC simulations. The scalable, spatially independent model can be used in laboratory and astrophysical parameter regimes while numerical constraints limit the parameter regimes treatable in the PIC simulations.

Comparison of particle-in-cell simulations and a wave-population model of electron-beam-plasma interactions

Clusters of galaxies contain large ellipticals near their cores. Elliptical galaxies in the centers of these clusters are often found to be the source of large-scale jets that propagate outward into the intracluster medium. These jets are thought to be produced by accretion-powered processes in the active galactic nuclei (AGN) at the centers of some giant ellipticals. In this paper, we discuss the origin of these jets and the likely consequences of their interactions with the intracluster medium in clusters of galaxies.

AGN Jet Interactions with the Intracluster Medium

An interpretation of X-ray observations of the (intracluster) gas in galaxy clusters, when combined with significant numerical work in simulating cluster formation, suggests that an additional heating mechanism is required to explain the dynamics and temperature profile in the intracluster medium (ICM). In addition to shock heating, star formation, and supernovae, a likely candidate for a heating mechanism for the ICM comes from the jets of material originating in the cores of active radio galaxies, themselves located in the cores of clusters. These large-scale jets propagate outward from the core of the galaxy into the intracluster medium. In this paper, we discuss the origin and energetics of these jets, the mechanisms of their propagation and energy loss, their constitution, and the likely consequences of their interactions with the intracluster medium in clusters of galaxies.

J. Guillory

Papers

Enhanced Landau damping of finite amplitude electrostatic waves in the presence of suprathermal electron tails

Comparison of particle-in-cell simulations and a wave-population model of electron-beam-plasma interactions

AGN Jet Interactions with the Intracluster Medium

Energetics of Jet Interactions with the Intracluster Medium

Observational signatures in jet-cloud interactions.