National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Relativistic effects in plasma produced with sub-nanosecond 3-TW laser
Krása, J. ; Klír, Daniel ; Řezáč, Karel ; Cikhardt, Jakub ; Krůs, Miroslav ; Velyhan, Andriy ; Pfeifer, Miroslav ; Dostál, Jan ; Dudžák, Roman ; Krupka, Michal ; Kaufman, J. ; Pisarczyk, T. ; Kalinowska, Z. ; Chodukowski, T.
This contribution deals with observations of relativistic electrons produced in a laser plasma interaction experiment at the PALS laser system operated at the Institute of Plasma Physics in Prague. The PALS laser is a near-infrared 3-TW iodine laser designed to deliver irradiance on target of 1016 Wcm2- in≈300 ps pulses at the wavelength of 1.315 μm. Various foils of 6 500 μm in thickness were irradiated with Iλ2 ≈5×1016 W cm-2 μm2 Under these conditions we have observed relativistic electrons expanding into the vacuum with maximum energy going beyond 4 MeV. The relativistically accelerated forward electrons escaping from the rear target surface were observed with the use of electron energy analysers. The observed electron energy spectra indicate that the applied laser intensity was increased by the thermal and relativistic self-focusing. The application of a unique femtosecond interferometry technique allowed us to observe bunches of thermal electrons occurring in the plasma expanding against the focused laser beam.
Laser-driven ablation through fast electrons in PALS experiment
Gus'kov, S. Yu. ; Chodukowski, T. ; Demchenko, N. ; Kalinowska, Z. ; Kasperczuk, A. ; Krouský, Eduard ; Pfeifer, Miroslav ; Pisarczyk, P. ; Pisarczyk, T. ; Renner, Oldřich ; Skála, Jiří ; Šmíd, Michal ; Ullschmied, Jiří
Energy transfer to shock wave in Al and Cu targets irradiated by a laser pulse with intensity of I~1-50 PW/cm2 and duration of 250 ps was investigated at Prague Asterix Laser System (PALS). The iodine laser provided energy in the range of 100-600 J at the first and third harmonic frequencies. The focal spot radius of laser beam on the target was varied from 160 to 40 µm. The dominant contribution of fast electron energy transfer into the ablation process was found when using the first harmonic radiation, the focal spot radius of 40-100 µm, and the energy of 300-600 J. The fast electron heating results in the growth of ablation pressure from 60 Mbar at the intensity of 10 PW/cm2 to 180 Mbar at the intensity of 50 PW/cm2 and in the growth of the efficiency of the energy conversion into the shock wave from 2 to 7 % under the conditions of 2D ablation.