Title :
Evidence and consequences of cathode-spot substructure in vacuum arcs
Author :
Juttner, Burkhard ; Förster, Andreas
Author_Institution :
Sektion Phys., Humboldt-Univ., Berlin, Germany
Abstract :
Time and spatial variations of vacuum arc spots have been studied by laser absorption and emission imaging techniques. It is shown experimentally that for t<10 ns there exist plasma structures with a size <5 μm. Experimental estimates of fragment size and lifetime are 1-2 μm and 1-2 ns, respectively. These estimates are supported by modelling the nonideal plasma state, based on the power input and the erosion rate. The model results in mean charge numbers of 2-3, electron temperatures of 8-9 eV, and plasma densities of about 1027 m -3
Keywords :
cathodes; electron field emission; electron microscopy; field emission electron microscopy; measurement by laser beam; plasma density; plasma temperature; vacuum arcs; 1 to 2 mum; 1 to 2 ns; cathode-spot substructure; electron temperatures; emission imaging technique; erosion rate; fragment lifetime; fragment size; laser absorption; mean charge numbers; nonideal plasma state modelling; plasma densities; plasma structures; power input; spatial variations; time variations; vacuum arc spots; vacuum arcs; Absorption; Electrons; Laser modes; Life estimation; Lifetime estimation; Plasma density; Plasma temperature; State estimation; Vacuum arcs; Vacuum technology;
Conference_Titel :
Discharges and Electrical Insulation in Vacuum, 1996. Proceedings. ISDEIV., XVIIth International Symposium on
Conference_Location :
Berkeley, CA
Print_ISBN :
0-7803-2906-6
DOI :
10.1109/DEIV.1996.545332
