Generation of Strongly Ionized Aluminum Plasma in a Low-Temperature Tokamak Discharge

Abstract

A new technique to produce a strongly ionized plasma from aluminum metal is achieved by use of the plasma-assisted arc in a tokamak discharge with low temperature (\lesssim10 eV), high electron density (\gtrsim1012 cm-3), and low gas pressure (10-5∼10-4 Torr). On arcing, the spectral lines of AlI, AlII and AlIII have been observed. Using the comparison spectroscopic method with no need of absolute measurement of spectral line intensity, we obtained the result that doubly ionized aluminum ions are dominant, and the density is estimated to be about 1011 cm-3. The aluminum plasma thus produced is useful and has potential for plasma processing, such as thin-film formation of AlN.

Nitriding of AISI 304 stainless steel by PIII in DC and RF toroidal discharges

“…The influence of the vacuum chamber geometry on many of the above mentioned processes can be considerable. Thus, for instance, in contrast to the most commonly used cylindrical geometry, in a toroidal one there are no end losses of plasma particles [10] owing to the application of equally toroidal magnetic fields in configurations close to those typical of nuclear fusion devices [11]. Due to this and similar potential uses of toroidal chambers, we are developing a line of research within our PIII programme with a view to reducing diffusion losses by means of toroidal magnetic confinement.…”

Ferromagnetic enhanced inductive plasma sources

“…A variety of high power (0.1-200 kW) plasma sources based on FMICP in toroidal metal chambers (Tokamak type discharges, or Transformer Coupled Toroidal Discharges, TCTD) operating at relatively low frequencies (10-580 KHz), in the gas pressure range between 10 −4 Tor up to atmospheric pressure, have been developed for laboratory study and manufactured for different industrial applications as described in [32,33,[41][42][43][44][45][46].…”

Characterization of gaseous carbon plasma in a low-temperature tokamak discharge

“…In figure 5 the carbon ion (C + ) density is plotted against the arc current, which is measured by means of the comparison spectroscopic method [5,6] mentioned below. On estimating the carbon ion density, the rate coefficient of electron impact excitation was quoted from [13].…”

“…We have proposed the generation of a gaseous plasma not from the volatile gas, but from the solid material by a plasma-assisted arc [5,6]. We apply this method to generating a high-density carbon plasma with a large volume in a low-temperature tokamak discharge [7,8].…”

“…We have measured the change in plasma parameters after arc ignition by a Langmuir probe, and quantitatively estimated the carbon ion density with the comparison spectroscopic method [5,6]. Two-dimensional distributions of spectral line intensities of carbon ionization states are qualitatively shown using an image-intensified charge coupled device (ICCD) camera.…”