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| Transport Phenomena of Electron Swarms |
| In this monograph we show the results of study of an electron swarm
moving in an unbounded neutral gas under the influence of the spatially
uniform electric and magnetic fields. Electrons gain the energy from the
external electric field and dissipate it through collisions to the neutral
gas molecules. Binary elastic, inelastic and reactive (attachment and
electron impact ionization) collisions are considered. The spatial and
temporal evolution of the electron swarm was determined by Monte Carlo
simulations. One of the major challenges in non-equilibrium plasma modeling is an exact description of electron kinetics. We note however, there are many explicit and implicit approximations among the parts of plasma models that concern the electron kinetics in DC and especially in RF fields. In this work an exact Monte Carlo method has been applied and by doing so, a number of non-equilibrium kinetic phenomena of electron transport were observed that cannot be predicted on the basis of approximate theories with limited accuracy. A data base for the electron transport coefficients for crossed electric and magnetic DC fields for carbon tetrafluoride (CF4) was made. The sensitivity of electron transport coefficients to energy dependent cross sections was studied. In addition, the influence of both magnetic field strenght and reactive (non-conservative) collisions on electron transport coefficients was considered. The presented electron transport parameters can be used as input data for fluid models of magnetron discharges. In the case of RF fields we show that the traditionally explanation of electron transport properties based on comparison between frequencies for energy and momentum relaxation with the frequency of the field is not correct. As illustrative examples, we demonstarte the effects of time resolved negative conductivity and the anomalous behavior of longitudinal component of diffusion tensor. Temporal non-locality of electron transport was identified as a major physical process that governs these phenomena. Aside of these effects, our attention was focused on the complex temporal profiles of electron transport coefficients resulting from a time resolved magnetic field. |
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| Publisher |
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Zadužbina Andrejević |
| Držićeva 11 |
| 11120 Belgrade |
| Serbia |
| Phones: +381 11 2401-045 |
| E-mail: zandrejevic@gmail.com |
| https://zandrejevic.rs |
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