NUKLEONIKA 2012, 57(2):227-230

 


INVESTIGATIONS OF MECHANISMS OF LASER RADIATION ABSORPTION AT PALS



Zofia Kalinowska1, Andrzej Kasperczyk1, Tadeusz Pisarczyk1, Tomasz Chodukowski1, Sergey Yu. Gus’kov2, Nicolai N. Demchenko2, Jiøí Ullschmied3, Eduard Krokusy3, Miroslav Pfeifer3, Jiøí Skala3, Pawe³ Pisarczyk4

1 Institute of Plasma Physics and Laser Microfusion, 23 Hery Str., 01-497 Warsaw, Poland
2 P. N. Lebedev Physical Institute, Russian Academy of Sciences,
53 Leninsky Ave., 119 991 Moscow, Russia
3 Institute of Plasma Physics, Academy of Sciences of the Czech Republic, v.v.i.,
3 Za Slovankou Str., 18200 Prague 8, Czech Republicy
4 Warsaw University of Technology, ICS, 15/19 Nowowiejska St., 00-665 Warsaw, Poland

Absorption mechanisms of laser radiation have been studied in the experiments at Prague Asterix Laser System (PALS – Prague, the Czech Republic) with normal incidence of iodine laser beams on plane massive targets made of Al and Cu. The investigations were performed for the first and the third harmonics of iodine laser radiation, four focal spot radii (40–160 µm) and laser pulse duration of 250 ps full width at half maximum (FWHM) at energy of 290 J. For the given target irradiation conditions, the laser intensity was varied in a range of 2.6 × 1015–4.1 × 1016 W·cm–2. Measurement of crater parameters by a cellulose acetate – replica technique and a three-frame interferometry were used as diagnostic tools. The experimental results allowed us to distinguish two areas of target irradiation parameters corresponding to resonance and inverse bremsstrahlung absorptions, respectively.

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