Effect of the Column Structure of the Arc Discharge in Vacuum on the Energy Efficiency of the Welding Process

An arc discharge with a hollow cathode in vacuum has two forms of steady state: diffuse ("blurred" external column) and constricted (a visible cylindrical column providing a high directivity of the discharge energy transfer with minimal scattering in the radial direction). The article considers the dependence of the energy concentration in the heating spot and, consequently, the energy efficiency of the welding process on the structure of the arc discharge column with a hollow cathode when changing its mode parameters. The distributions of local parameters of the arc discharge with hollow cathode plasma are shown in a wide range of its modes based on probe studies. Considering the distributions allows obtaining a fairly complete picture of the physical processes in the plasma of the external discharge column and the effect of its structure on the energy efficiency of the welding process. It is shown that an arc discharge with a hollow cathode in a vacuum, the outer column of which has the structure of a plasma beam, is a relatively highly concentrated energy source and in terms of specific energy indicators can reach an energy concentration second only to beam energy sources.

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