Cathodic arcs: Fractal voltage and cohesive energy rule
- Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
The noise of the burning voltage of cathodic arcs in vacuum was analyzed for a range of cathode materials (C, Mg, Ti, V, Ni, Cu, Zr, Nb, Ag, Hf, Ta, W, Pt, Bi, and Si). Cathodic arcs were generated in a coaxial plasma source, and the voltage noise was measured with a broadband measuring system. Each measurement was analyzed by fast Fourier transform, revealing a power spectrum {approx}1/f{sup 2} for all cathode materials over several orders of magnitude of frequency f (brown noise). The absence of any characteristic time down to possible cutoffs at high frequencies supports a fractal model of cathode spots. The amplitude of colored noise scaled approximately linearly with the cathode's cohesive energy, which is another manifestation of the cohesive energy rule.
- OSTI ID:
- 20702393
- Journal Information:
- Applied Physics Letters, Vol. 86, Issue 21; Other Information: DOI: 10.1063/1.1937994; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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