Cathode-Spot Dynamics in a High-Current Pulsed Arc: A Noise Study

Author

Ryves, Luke ; McKenzie, David R. ; Bilek, Marcela M.M.

Author_Institution

Sch. of Phys., Univ. of Sydney, Sydney, NSW

Volume

37

Issue

2

fYear

2009

Firstpage

365

Lastpage

368

Abstract

Cathode spots are the locus for plasma production in cathodic vacuum arcs, and measurements of the discharge voltage provide information about the physics. The voltage noise and cathode-erosion patterns of a high-current pulsed titanium arc were studied as a function of time, current, and pulse shape. Enhanced noise and a 1/f³ trend in the spectral power density were observed when cathode spots are close together at the initiation of an arc for fast rising currents (>1.3 kA in 30 mus) or when the total current exceeds a threshold value of 1.6 kA. We propose a model in which the individual currents associated with the spot substructure can act as noise generators coupled via magnetic fields or coherent spot nucleation.

Keywords

cathodes; plasma diagnostics; plasma production; vacuum arcs; voltage measurement; cathode erosion patterns; cathode-spot dynamics; cathodic vacuum arcs; coherent spot nucleation; current 1.6 kA; discharge voltage measurements; high current pulsed arc; high current pulsed titanium arc; noise generators; plasma production; spectral power density; spot substructure; voltage noise; Cathodic arc; noise; plasma; vacuum arc;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/TPS.2008.2007734

Filename

4768715