Anode phenomena in vacuum arcs

Technical Report · Sun Feb 20 04:00:00 EST 1983

OSTI ID:6460078

Miller, H C

This paper reviews anode phenomena in vacuum arcs, specially experimental work. It discusses in succession arc modes at the anode, anode temperature measurments, anode ions, transitions of the arc into various modes (principally the anode spot mode), and theoretical explanations of anode phenomena. The two most common anode modes in a vacuum arc are a low current mode where the anode is basically passive, acting only as a collector of particles emitted from the cathode, and a high current mode with a fully developed anode spot. Characteristically this anode spot has a temperature near the atmospheric boiling point of the anode material and is a copious source of vapor and energetic ions. A vacuum arc doesn't always transfer directly from a low current mode to the anode spot mode. In appropriate experimental conditions formation of an anode spot may be preceded by the formation of an anode footpoint. Finally, several small anode spots may form instead of one large anode spot. With sufficient increase in arc current or arcing time these will usually combine to form a single large active anode spot. The dominant mechanism controlling the transition of the vacuum arc into the anode spot mode depends upon the electrode geometry, the electrode material, and the current waveform of the particular vacuum arc being considered. In specific experimental conditions either magnetic constriction in the gap plasma or gross anode melting or evaporation can trigger the transition. However, the most probable explanation of anode spot formation is a combination theory, which considers magnetic constriction in the plasma together with the thermal, mechanical, and electrical effects of the anode in analyzing the interaction between the gap plasma near the anode and the anode itself.

• Research Organization: General Electric Co., St. Petersburg, FL (USA). Neutron Devices Dept.
• DOE Contract Number: AC04-76DP00656
• OSTI ID: 6460078
• Report Number(s): GEPP-TIS-657; ON: DE83007181
• Country of Publication: United States
• Language: English

Related Subjects

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANODES
BREAKDOWN
CRITICAL CURRENT
CURRENTS
DOCUMENT TYPES
ELECTRIC ARCS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
ELECTRIC POTENTIAL
ELECTRODES
LUMINOSITY
NOISE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
REVIEWS
SPUTTERING
TEMPERATURE MEASUREMENT