A model for a uniform steady-state vacuum arc with a hot anode |
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Authors: | Boxman RL Goldsmith S |
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Institution: | Electr. Discharge & Plasma Lab., Tel Aviv Univ.; |
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Abstract: | A model is formulated and evaluated for a Uniform electrical discharge sustained in vapor evaporated from an arc-heated anode. The plasma potential is positive with respect to both the cathode and anode. For a Cu anode, the anodic vapor dominates the plasma for current densities exceeding 8 kA/m2. The anode heating potential is approximately 6.5 V, and the dominant cooling mechanism is evaporation for current densities exceeding 20 kA/m2. Over the range 10 to 10000 kA/m2, the electron density increases from 8×1017 to 5×1023 m-3, while the ionization fraction rises from 0.3% to 4%. At the lower end of this current range the electrical resistivity of 4 mΩ-m is determined primarily by electron-neutral collisions, while with increasing current the resistivity decreases to 0.7 mΩ-m, with electron-ion collisions contributing an equal share. This hot-anode vacuum arc may have potential for industrial application as a macroparticle-free high-deposition-rate coating source |
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