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The anode boundary layer of an argon free burning arc is investigated using a two-temperature model, which includes convection and charge particle diffusion. The detailed structure of the boundary layer in terms of charge density, electron and ion temperature, and electrical potential distribution is given for two discharge currents, 100 A and 200 A. The energy flux received by the anode is also given.
Summary form only given. A mixture of hydrogen with primary plasma gas argon has been used to investigate some fundamental aspects of arc instability in an SG-100 spray torch. In such arcs, owing to inherent demixing processes, the boundary layer and the core of the plasma column are dominated by hydrogen and argon respectively. Therefore, associated variations in instability features due to variation...
Summary form only given. Electric field distributions are measured around a biased probe immersed in an argon discharge. The distributions are measured as functions of probe bias, argon pressure, and distance of the probe from the "boundary" placed on the plasma by a powered electrode. The electric fields are symmetrically distributed around the probe when the probe is placed sufficiently...
Summary form only given. Electron sheaths are electric fields that form near plasma boundaries to preserve quasineutrality in the bulk plasma by reducing the positive ion current lost to a boundary. Previous conjectures hypothesize that electron sheath formation near a positive anode is a solution to the current balance when the ratio of the anode area, Aa, to the chamber wall area, Aw, is less than...
Summary form only given. Analysis of the conduction current on the negatively biased target is important to develop the pulse switch system and to improve the material surface treatment using the plasma source ion implantation. In case of highly negative biased target immersed in the plasma, the current on the target is composed of the incident ion current and the electron emission current. The virtual...
Summary form only given. Electron extraction at electron sheaths (i.e. positive going anode sheaths) is studied in weakly magnetized RF inductive plasmas. As with DC plasmas produced with hot filaments, it is shown that all of the electrons created by ionization in the plasma can be extracted from the plasma. The electrons are extracted through a grounded ring and in the presence of a weak axial magnetic...
Summary form only given. Anode boundary layers of high intensity arcs are important for many industrial applications, such as plasma spray torches. In this study, laser Thomson scattering has been used to measure the distributions of the electron temperature and the electron density in the anode boundary layer of an atmospheric pressure, high intensity transferred argon arc. The electron temperature...
This paper describes the results of an experimental investigation on the effect of magnetohydrodynamic (MHD) interaction with the plasma of the shock layer at a test body in a hypersonic argon flow. The hypersonic flow is obtained from the high-enthalpy arc-heated wind tunnel of Alta, Pisa, Italy, on Mach 6. Tests are carried out at heating chamber stagnation pressures of 0.65, 0.85, and 1 bar and...
Summary form only given. Current transfer to cathodes of high-pressure arc discharges may occur in a diffuse mode, when the current is distributed along the front surface of the cathode in a more or less uniform way, and in spot modes, when nearly all the current is concentrated in one or several regions (cathode spots) which occupy only a small fraction of the cathodes surface. If the cathode is...
Summary form only given. Anode boundary layers of high pressure, high intensity arcs are characterized by large gradients of temperature, charged particle density and gas velocity. In this study, a planar Langmuir probe has been used to study the anode boundary layer of an atmospheric pressure, high intensity transferred argon arc with lateral cold gas flow. The measurements were performed with different...
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