Vacuum arc plasma jet interaction with neutral ambient gas

E. Gidalevich*, S. Goldsmith, R. L. Boxman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Vacuum arc plasma jet (VAPJ) propagation in a neutral nitrogen atmosphere has been calculated numerically on the basis of a hydrodynamic description. It was assumed that the VAPJ was emitted isotropically from a point source located z0 = 20 mm in front of the entrance of a straight duct 100 mm in diameter in which an axial magnetic field of 0.02-0.05 T was imposed. Plasma densities of n0 = 1018 and 1019 m-3 and neutral gas densities nn0 = 0.001-0.1×n0 were used as initial conditions at the duct entrance. A three-fluid model was used, with the ion temperature having an initial value at the duct entrance of Ti = 104 K, while constant temperatures of Te = 3×104 K and Tn = 103 were assumed for the electrons and neutrals, respectively. It was found that the plasma jet decelerates down to the critical point, i.e. where the jet velocity is equal to the local speed of sound. The distance of the critical point from the entrance cross section decreased from Zc = 4×R (R = radius of duct) for nn0 = 0.001×n0 down to zc = R for nn0 = 0.1×n0. It was found that increasing the magnetic field also decreased zc. It was also found that the electrons and ions have rotational motion components, in opposite directions, and that friction with the neutral gas decreases the rotational velocities.

Original languageEnglish
Pages (from-to)2598-2604
Number of pages7
JournalJournal of Physics D: Applied Physics
Issue number20
StatePublished - 21 Oct 2000


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