Monte Carlo simulation of electron kinetics in a hollow cathode discharge

A kinetic model is reported computing the electron behavior in a hollow cathode discharge based on the Monte Carlo technique. It is a part of the PLASIMO modelling toolkit. The model allows the electrons to be closely followed while they travel and undergo collisions in the discharge. The Monte Carlo modulewas applied to the case of a HCD used as an excitation medium of atoms obtained by laser ablation. Results are obtained on the electron energy distribution function and the mean electron energy under typical discharge conditions. The output data and future development of the model and its applications are analyzed and discussed

Monte Carlo simulation of a sputtering hollow-cathode discharge for laser applications

We report on a kinetic model that computes the electron behaviour in a hollow cathode discharge. It is a part of the PLASIMO toolkit and is based on a Monte-Carlo technique. The model is tested by varying the input parameters and by comparing the output with the output obtained by the freeware Boltzmann equation solver BOLSIG+. The results show that the Monte-Carlo model gives reliable information about the behavior of the electrons in the discharge. The Monte-Carlo module is applied to the case of a hollow cathode discharge for laser applications. Analysis of the output data and its adequateness is done. Future developments of the model are discussed

Kinetic simulation of an extreme ultraviolet radiation driven plasma near a multilayer mirror

Future generation lithog. tools will use extreme UV radiation to enable the printing of sub-50 nm features on silicon wafers. The extreme UV radiation, coming from a pulsed discharge, photoionizes the low pressure background gas in the tool. A weakly ionized plasma is formed, which will be in contact with the optical components of the lithog. device. In the plasma sheath region ions will be accelerated towards the surfaces of multilayer mirrors. A self-consistent kinetic particle-in-cell model has been applied to describe a radiation driven plasma. The simulations predict the plasma parameters and notably the energy at which ions impact on the plasma boundaries. We have studied the influence of photoelectron emission from the mirror on the sheath dynamics and on the ion impact energy. Furthermore, the ion impact energy distribution has been convoluted with the formula of Yamamura and Tawara [At. Data Nucl. Data Tables 62, 149 (1996)] for the sputter yield to obtain the rate of phys. sputtering. The model predicts that the sputter rate is dominated by the presence of doubly ionized argon ions. [on SciFinder (R)

Temperature fitting of partially resolved rotational spectra

In this paper we present a method to automatically fit the temperature of a rotational spectrum. It is shown that this fitting method yields similar results as the traditional Boltzmann plot, but is applicable in situations where lines of the spectrum overlap. The method is demonstrated on rotational spectra of nitric oxide from an atmospheric pressure microwave plasma jet operated with a flow of helium and air, obtained with two different methods: laser induced fluorescence and optical emission spectroscopy. Axial profiles of the rotational temperatures are presented for the ground NO X state and the excited NO A state

Langmuir probe measurements in an expanding magnetized plasma

Langmuir probe measurements were performed in magnetized expanding plasmas of different compns. Under the assumption that a function fitted to results in argon is valid in other plasmas, it is possible to study the influence of the magnetic field in nitrogen and hydrogen plasmas. The electron d. in nitrogen can be increased by a factor of 10 by the application of a magnetic field of 4.5 mT. In hydrogen the d. can be increased by a factor of 100 by a magnetic field of 20 mT. The dominant ionic species in the magnetized nitrogen and hydrogen plasmas is the at. ion (N+ and H+, resp.). [on SciFinder (R)

The energy balance of Hg-free HID lamps and the influence of electrode distance

Abstract only

Deviations from the local field approximation in negative streamer heads

Negative streamer ionization fronts in nitrogen under normal conditions are investigated both in a particle model and in a fluid model in local field approximation. The parameter functions for the fluid model are derived from swarm experiments in the particle model. The front structure on the inner scale is investigated in a 1D setting, allowing reasonable run-time and memory consumption and high numerical accuracy without introducing super-particles. If the reduced electric field immediately before the front is >= 50kV/(cm bar), solutions of fluid and particle model agree very well. If the field increases up to 200kV/(cm bar), the solutions of particle and fluid model deviate, in particular, the ionization level behind the front becomes up to 60% higher in the particle model while the velocity is rather insensitive. Particle and fluid model deviate because electrons with high energies do not yet fully run away from the front, but are somewhat ahead. This leads to increasing ionization rates in the particle model at the very tip of the front. The energy overshoot of electrons in the leading edge of the front actually agrees quantitatively with the energy overshoot in the leading edge of an electron swarm or avalanche in the same electric field.Comment: The paper has 17 pages, including 15 figures and 3 table

Discrepancies between different electron temperature methods: probing the electron energy distribution function

A large panel of diagnostic techniques for the determination of effective electron temperatures Te exists and they rely on different hypothesis/physical phenomena for its measurement. Due to the different underlying assumptions and physical mechanisms used for the calculation of Te, different values of Te may be expected while measuring a plasma in the same conditions, particularly in the case of a non-Maxwellian plasma. To each of these definitions of effective Te, a different effective Te can be defined using the EEDF of the plasma. In this study, we take a low pressure Argon microwave plasma as test case and compare Thomson scattering with line intensity measurements corrected by a collisional radiative model. The results are compared with those obtained from the electron particle balance (ePB)

Departures from local thermodynamic equilibrium in HID lamps

No abstract