167 research outputs found
Plasma cleaning of ITER first mirrors in magnetic field
To avoid reflectivity losses in ITER optical diagnostic systems, plasma
sputtering of metallic First Mirrors is foreseen in order to remove deposits
coming from the main wall (mainly beryllium and tungsten). Therefore plasma
cleaning has to work on large mirrors (up to a size of 200*300 mm) and under
the influence of strong magnetic fields (several Tesla). This work presents the
results of plasma cleaning of aluminium and aluminium oxide (used as beryllium
proxy) deposited on molybdenum mirrors. Using radio frequency (13.56 MHz) argon
plasma, the removal of a 260 nm mixed aluminium/aluminium oxide film deposited
by magnetron sputtering on a mirror (98 mm diameter) was demonstrated. 50 nm of
pure aluminium oxide were removed from test mirrors (25 mm diameter) in a
magnetic field of 0.35 T for various angles between the field lines and the
mirrors surfaces. The cleaning efficiency was evaluated by performing
reflectivity measurements, Scanning Electron Microscopy and X-ray Photoelectron
Spectroscopy.Comment: 5 pages, 6 figures and 1 table. Results presented on the 21st Plasma
Surface Interaction conference held in Kanazawa Japan, May 201
Decontamination of a rotating cutting tool during operation by means of atmospheric pressure plasmas
Translational, rotational and vibrational temperatures of a gliding arc discharge at atmospheric pressure air
Gliding arc discharges have generally been used to generate non-equilibrium plasma at atmospheric pressure. Temperature distributions of a gliding arc are of great interest both for fundamental plasma research and for practical applications. In the presented studies, translational, rotational and vibrational temperatures of a gliding arc generated at atmospheric pressure air are investigated. Translational temperatures (about 1100 K) were measured by laser-induced Rayleigh scattering, and two-dimensional temperature imaging was performed. Rotational and vibrational temperatures (about 3600 K and 6700 K, respectively) were obtained by simulating the measured emission spectra of OH
Translational, rotational, vibrational and electron temperatures of a gliding arc discharge
Translational, rotational, vibrational and electron temperatures of a gliding arc discharge in atmospheric pressure air were experimentally investigated using in situ, non-intrusive optical diagnostic techniques. The gliding arc discharge was driven by a 35 kHz alternating current (AC) power source and operated in a glow-type regime. The two-dimensional distribution of the translational temperature (Tt) of the gliding arc discharge was determined using planar laser-induced Rayleigh scattering. The rotational and vibrational temperatures were obtained by simulating the experimental spectra. The OH AâX (0, 0) band was used to simulate the rotational temperature (Tr) of the gliding arc discharge whereas the NO AâX (1, 0) and (0, 1) bands were used to determine its vibrational temperature (Tv). The instantaneous reduced electric field strength E/N was obtained by simultaneously measuring the instantaneous length of the plasma column, the discharge voltage and the translational temperature, from which the electron temperature (Te) of the gliding arc discharge was estimated. The uncertainties of the translational, rotational, vibrational and electron temperatures were analyzed. The relations of these four different temperatures (Te>Tv>Tr >Tt) suggest a high-degree non-equilibrium state of the gliding arc discharge
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