Ion energy distribution functions of vacuum arc plasmas

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The velocity distribution function of vacuum arc ions can be measured by a time-of-flight technique similar to a method originally proposed by Yushkov. The measuring principle makes use of the well-justified assumption that the ion drift velocity from the cathode spot region to a collector is approximately constant. It is shown that the negative time derivative of the collector current is directly proportional to the ion distribution function provided that the time-averaged source intensity (i.e., emission of ions from cathode spots) is constant until the arc is rapidly switched off. In the experiment, arc termination took about 700 ns, which ... continued below

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Byon, Eungsun & Anders, Andre September 16, 2002.

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The velocity distribution function of vacuum arc ions can be measured by a time-of-flight technique similar to a method originally proposed by Yushkov. The measuring principle makes use of the well-justified assumption that the ion drift velocity from the cathode spot region to a collector is approximately constant. It is shown that the negative time derivative of the collector current is directly proportional to the ion distribution function provided that the time-averaged source intensity (i.e., emission of ions from cathode spots) is constant until the arc is rapidly switched off. In the experiment, arc termination took about 700 ns, which is much faster than the decay of the ion current measured at the collector placed in more than 2 meters distance from the cathode. The experimental distribution functions for most cathode materials show one large peak with a tail and one or more small peaks at higher ion velocities. The distribution functions for some other materials exhibit several peaks. No conclusive answer can be given about the nature of these peaks. Arguments are presented that the peaks are not caused by different charge states or plasma contamination but rather due to insufficiently averaged source fluctuations and/or acceleration by plasma instabilities.

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  • Journal Name: Journal of Applied Physics; Journal Volume: 93; Journal Issue: 4; Related Information: Journal Publication Date: 02/15/2003

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  • Report No.: LBNL--51488
  • Grant Number: DE-AC02-05CH11231
  • Office of Scientific & Technical Information Report Number: 917335
  • Archival Resource Key: ark:/67531/metadc880870

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Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

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  • September 16, 2002

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  • Sept. 22, 2016, 2:13 a.m.

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  • Sept. 21, 2017, 3:53 p.m.

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Byon, Eungsun & Anders, Andre. Ion energy distribution functions of vacuum arc plasmas, article, September 16, 2002; Berkeley, California. (digital.library.unt.edu/ark:/67531/metadc880870/: accessed October 17, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.