Analysis of Electron Dynamics in Non-Ideal Penning Traps

In Penning traps that are used for particular applications, such as in ion pump technology, Larmor, bouncing and diocotron frequencies can be of the same order of magnitude. The paper deals with the dynamics of electrons confined in such devices starting from the study of the properties of the trajectories. In cases of interest, in which electron-neutral collision frequency is much smaller with respect to the characteristic frequencies of the motion, suitable time averages of the trajectories are introduced in order to simplify the analysis of the problem. In the work, time averages have been calculated in a simple way by using an approximate r−z decoupling of the effective potential. Results obtained with the method are presented and discussed in both linear and nonlinear regimesPenning trap, ergodic methods, electron dynamics, time-averag

Thermodynamic properties of high temperature air in local thermodynamic equilibrium: II accurate analytical expression for electron molar fractions

An extremely accurate analytical expression for electron molar fractions in LTE air plasma in the temperature range 50–20 000 K and in the pressure range 10^−3 ÷ 10^3 bar is reported. Results have been obtained by using self-consistent cutoff and inserting Debye-Huckel corrections

A selfconsistent unstructured solver for weakly ionized gases

A selfconsistent unstructured solver for weakly ionized gases modeling inviscid multi-species conservation equations coupled with a reduced state-to-state kinetics model is presented. Mathematical model have been implemented in EulFS, a CFD unstructured solver using Residual Distribution Schemes, to discretize convective fluxes and chemical source terms. A simple model which couples the weakly ionized gas with an electric field controlled by considering a power supply and an external circuit resistence Rc is considered. Preliminary results will be shown for an argon plasma considering different 2D and 3D geometrical configurations

The ergodic method: plasma dynamics through a sequence of equilibrium states

In problems of plasma physics, characterized by the simultaneous presence of phenomena spanning well-separated time scales, theoretical methods can be devised in which time averages over the more rapid phenomenon are performed in order to calculate the parameters for the study of the evolution of the slower one. In some respects, the idea behind these methods is similar to the concept of ergodic theory in kinetic theory

A phenomenological approach for the transport properties of air plasmas

The transport coefficients of Earth atmosphere in equilibrium, in wide temperature and pressure ranges, have been calculated using collision integrals derived in a phenomenological approach, accounting also for resonant processes contributions. This approach could be a valuable tool in the calculation of complete data sets for complex mixtures, including interactions hardly handled in the accurate multi-potential methods. A systematic comparison with transport coefficients obtained using an old data set, widely used in literature, has been carried out to estimate the reliability of the proposed approach in evaluating transport cross sections

Modeling and Simulation of Low Current Atmospheric and High-Pressure Helium Plasma Discharges

A plasma discharge in a Helium gas reactor at different pressures and at low currents (0.25-0.45 A) has been investigated by Computational Fluid Dynamic modeling coupled with the Maxwell's equations. The results show different discharge dynamics across the pressure range (0.1-8 MPa), with an arc discharge obtained at high pressure and a low current arc discharge observed at atmospheric pressure. A large density gradient at higher pressure causes a strong natural convection effect in the reactor. This density gradient affects drastically the discharge shape and the velocity field at high pressures while at atmospheric pressure, a lower density gradient was observed resulting in a low velocity magnitude. It has been observed that the velocity magnitude is not affected by the electric current. The discharge electric potential has been calculated by considering the electrical characterization of the electrodes and numerical results have been compared with experimental results. The comparison shows a good agreement between the measured and calculated discharge electric potential at lower pressures. These devices can be used as plasma sources for wastewater treatment