Compact Plasma and Focused Ion Beams

148 Compact Plasma and Focused Ion Beams

buildup occurs after the end of the pulse in a timescale of 2−20 μs. The

buildup is faster at a higher p at a position near the entrance, z = 2 cm.

At locations farther away from the entrance, z = 10−15 cm (e.g., z = 10 cm,

Figure 9.3b), the buildup was delayed at a higher p. However, again at

z = z

m

= 20−30 cm (e.g., z = 20 cm, Figure 9.3c, i.e., the region of second

current peak in Figure 9.2a and b), the buildup followed that of z = 2 cm.

Therefore, the buildup process is different in the area between the two

regions, with a higher plasma density. The same feature has also been

found for the ion cur ...