
262 Compact Plasma and Focused Ion Beams
corresponds to the pressure at which the plasma steady state is observed in
Figure 16.4. As we will soon see, from these data we may infer that the attop
duration follows the simulation trend.
Figure 16.7 shows the variation of the optical intensity at 404 nm at
60 mTorr in comparison with the microwave pulse. It may be noted that
the intensity of the 404 nm optical line has a delayed buildup and remains
10.000
1.000
0.100
J
me
(mA/cm
)
0.010
0.001
0.001 0.010
f
r
25 Hz
50 Hz
100 Hz
246 Hz
0.100
FIGURE 16.5
Variation of the peak electron current density J
me
with pressure p and pulse repetition f