Electron Groups in Solar Wind and Gas Discharge Plasmas

Plasma Stratification in Radio-Frequency Discharges of Noble Gases

We conducted experimental studies and computer simulations of standing striations in capacitive coupled plasma in Argon gas. Standing striations were observed at frequencies 3.6, 8.4 and 19.0 MHz, in a pressure range 0.05-10 Torr, tube radius R=1.1 cm, for a certain range of discharge currents (plasma densities). Numerical simulations revealed similar nature of standing striations in CCP and moving striations in DC discharges under similar discharge conditions. Comparison of computer simulations with experimental observations helped clarify the nature of these striations. The non-linear depend…

Particle-in-Cell/Test-Particle Simulations of Technological Plasmas: Sputtering Transport in Capacitive Radio Frequency Discharges

The paper provides a tutorial to the conceptual layout of a self-consistently coupled Particle-In-Cell/Test-Particle model for the kinetic simulation of sputtering transport in capacitively coupled plasmas at low gas pressures. It explains when a kinetic approach is actually needed and which numerical concepts allow for the inherent nonequilibrium behavior of the charged and neutral particles. At the example of a generic sputtering discharge both the fundamentals of the applied Monte Carlo methods as well as the conceptual details in the context of the sputtering scenario are elaborated on. Fi…

Self-pulsing of a micro thin cathode discharge

Microplasmas operated at atmospheric pressure show a number of peculiar dynamic phenomena. One of these phenomena is self-pulsing, which is characterized by intrinsic pulsing behavior of a DC driven plasma discharge. This work focuses on the numerical simulation of self-pulsing in a micro thin cathode discharge operated in atmospheric pressure argon. By means of a hybrid plasma model we show self-pulsing of the discharge in the expected MHz frequency range and described its actual origin.

Numerical simulation of Ni-like Xe plasma dynamics and laser gain in a low inductivity capillary discharge

X-ray lasers based on transitions in highly charged \textit{Ni}-like ions generating in the "water window" wavelength range can be pumped by compact laboratory discharge sources. This makes them promising candidates for use as compact coherent X-ray sources in laboratory applications including biological imaging and investigations of carbon containing materials. In this paper, the results of numerical simulations of the plasma dynamics and kinetics in an X-ray laser based on transitions in \textit{Ni}-like xenon ions are reported. The laser active medium is created by an extended low-inductive…

Ionization waves (striations) in low-current DC discharges in noble gases obtained with a hybrid kinetic-fluid model

A hybrid kinetic-fluid model is used to study ionization waves (striations) in a low-current plasma column of DC discharges in noble gases. Coupled solutions of a kinetic equation for electrons, a drift-diffusion equation of ions, and a Poisson equation for the electric field are obtained to clarify the nature of plasma stratification in the positive column and near-electrode effects. A simplified two-level excitation-ionization model is used for the conditions when the nonlinear effects due to stepwise ionization, gas heating, and Coulomb interactions among electrons are negligible. It is con…

外加场强对各种推进剂ExB等离子体放电中等离子体行为与过程的影响：I. 电场

Effects of the applied fields' strength on the plasma behavior and processes in ExB plasma discharges of various propellants: I. Electric field

本文利用降阶PIC方案研究外加电场和磁场强度对二维径向-方位角配置下氙、氪、氩无碰撞ExB等离子体放电的影响，发现电场强度决定了由MTSI或ECDI主导的两种不同等离子体状态，并导致电子电流密度径向分布和温度各向异性的变化。