Excited-state densities in a multicathode-spot Al vacuum arc. I. Spectroscopic measurements

Raymond L. Boxman*, S. Goldsmith

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Excited-state densities in the interelectrode plasma produced by a 1.2-kA-peak-current 0.65-ms HAFW discharge between Al butt electrodes, 12 mm in diameter spaced 4.4 mm apart and located in a vacuum ambient, were determined by measurement of the absolute line intensities. Densities divided by degeneracies at midplane near peak current for the Al I 3s2 4s2S, Al II 3p2 1D, and Al III 4p 2p states were 8×1014, 2×1016, and 3×1016 m-3, respectively. Densities in Al II and Al III states studied could be described by distribution temperatures of 1.1 and 1.2 eV, respectively. As a function of distance from the cathode, Al I and Al II densities declined from their maximum near the cathode, with the Al I density rising slightly near the anode, while Al III states generally rose from minimum values near the cathode, reaching maximums after midplane. As a function of time, Al III densities reached a maximum near current maximum, and then decayed rapidly, while Al II densities reached their maximum about 0.2 ms after peak current, and Al I reached its maximum only near the tail end of the current pulse.

Original languageEnglish
Pages (from-to)3644-3648
Number of pages5
JournalJournal of Applied Physics
Issue number7
StatePublished - 1980


Dive into the research topics of 'Excited-state densities in a multicathode-spot Al vacuum arc. I. Spectroscopic measurements'. Together they form a unique fingerprint.

Cite this