On the nature and the motion of arc cathode spots in UHV
On the nature and the motion of arc cathode spots in UHV
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特高压电弧阴极斑的性质及其运动
DOI：
10.1002/ctpp.19790190305
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发表时间：
1979
影响因子：
1.6
通讯作者：
H. Pursch
中科院分区：
文献类型：
--
作者：
A. I. Bushik;B. Jüttner;H. Pursch
本文研究了超高真空中大面积钼铜阴极弧斑的类型和弧斑运动。电弧电流为20-60 A DC和8-20 kA脉冲（持续时间约1 ms）。两种类型的斑点发生不同的速度和表面侵蚀：类型1点是典型的表面覆盖的氧化物或厚的吸附层，而干净的表面只显示类型2点。
在电弧调节期间，这两种类型以复杂的相互依赖性同时存在。第1类斑点在阴极材料上反应较弱，而第2类斑点优先在Cu上和Mo与Cu之间的边界线处燃烧。第1类斑点的运动是由扩展的斑点等离子体决定的，而第2类斑点显示出一个步进式的运动，由电弧坑中的爆炸决定。一般来说，电弧等离子体下方的2型点的自发形成仅发生在污染的表面（可能通过从1型点到2型点的过渡）。因此，等离子体和阴极表面之间的击穿需要污染物的存在。所观察到的效果发生在低电流直流电弧以及在高电流脉冲电弧。他们讨论了不同的斑点模型。
Cathode spot types and spot motion of arcs in ultra high vacuum have been investigated with large area cathodes that consisted of two adjacent pieces of Mo and Cu. Arc currents were 20–60 A dc and 8–20 kA pulse (duration about 1 ms). Two spot types occured with different velocities and surface erosion: Type 1 spots are typical for surfaces covered by oxides or thick adsorption layers, whereas clean surfaces show only type 2 spots.
During arc-conditioning both types exist simultaneously in a complex mutual dependence. Type 1 spots react weakly on the cathode material, while type 2 spots burn preferentially on Cu and at the boundary line between Mo and Cu. The motion of type 1 spots is determined by the expanding spot plasma, whereas type 2 spots show a step-by step motion, determined by explosions in the arc craters. Generally a spontaneous formation of type 2 spots beneath the arc plasma takes place only with contaminated surfaces (probably by a transition from type 1 to type 2 spots). Thus a breakdown between plasma and cathode surface requires the presence of contaminations. The observed effects occur in low current dc-arcs as well as in high current pulse arcs. They are discussed for different spot models.