
April 24, 2014 17:34 PSP Book - 9in x 6in 04-Rashid-A.-Ganeev-c04
110 High-Order Harmonic Generation in Plasma Plumes Using Picosecond Pulses
The increase of heating pulse intensity on the target surfaces
above 10
11
W/cm
2
led to both the growth of emission intensity
for neutral and singly charged ionic species and the appearance of
emission lines from the higher charged particles. The appearance
of doubly and triply charged ions and large amount of free
electrons immediately followed with considerable decrease of HHG
conversion efficiency from almost all the plasma samples. The
variations of plasma spectra in that case are presented in Fig. 4.2b,
in which ...