Asymmetric injection of cathodic arc plasma into a macroparticlefilter
The cathodic arc plasmas produced by cathode spots usuallyinclude macroparticles, which is undesirable for many applications. Acommon way of removing macroparticles is to use curved solenoid filterswhich guide the plasma from the source to the substrate. In this work, anarc source with relatively small cathode is used, limiting the possiblelocations of plasma production. The relative position of cathodic arcsource and macroparticle filtered was systematically varied and thefiltered plasma current was recorded. It was found that axis-symmetricplasma injection leads to maximum throughput only if an anode aperturewas used, which limited the plasma to near-axis flow by scraping offplasma at larger angles to the axis. When the anode aperture was removed,more plasma could enter the filter. In this case, maximum filtered ioncurrent was achieved when the plasma was injected off-axis, namely offsetin the direction where the filter is curved. Such behavior wasanticipated because the plasma column in the filter is known to beshifted by ExB and centrifugal drift as well as by non-axis-symmetriccomponents of the magnetic field in the filter entrance and exit plane.The data have implications for plasma transport variations caused bydifferent spot locations on cathodes that are not small compared to thefilter cross section.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science; Industry
- DOE Contract Number:
- DE-AC02-05CH11231; INDUSTRY:LBNL-SOW000416
- OSTI ID:
- 882146
- Report Number(s):
- LBNL-54195; JAPIAU; R&D Project: Z2PASV; BnR: 600301010; TRN: US0805843
- Journal Information:
- Journal of Applied Physics, Vol. 95; Related Information: Journal Publication Date: 15 June 2004; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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