Документ взят из кэша поисковой машины. Адрес оригинального документа : http://ofvp.phys.msu.ru/en/science_education/diploma/annot/2014/Larkin_Uryupina_en.pdf Дата изменения: Wed Dec 25 12:23:02 2013 Дата индексирования: Sun Apr 10 04:20:59 2016 Кодировка:

Interaction of the relativistic laser pulse with the melted metal surface Larkin Alexey Annotation of the graduation work Investigation of high-energy particles generation and in particular generation of hard x-ray radiation and gamma radiation is an important and interesting problem of studying of high power laser-matter interaction. This is connected both with the solution of a large number of applications and with understanding and identifying regularities of physical processes. We have investigated the possibility of increasing of hard x-ray radiation yield in case of interaction of the relativistic laser pulse with microstructured by the action of the laser pre-pulse (ahead the main pulse for a few nanoseconds) surface of the melted gallium target. In the experiments we used the laser radiation delivered by the Ti:Sa laser system (wave length 800 nm, pulse duration - 50 fs, pulse energy - up to 75 mJ, repetition rate - 10 Hz, contrast at the nanosecond scale - 510-8). Comparison of results of the optical shadowgraphy of the plasma plume formed by the action of the laser pre-pulse with results of measurements of the energy distribution in the focal area allowed us to bind the micro-jets formation with the features of energy fluence. Variation of the artificially created laser pre-pulse parameters (energy and lead time) allows us to establish the nature of the impact of the preplasma formed by the action of the laser pre-pulse on the hard x-ray generation after interaction of the main pulse with preplasma. We achieved generation of the hard x-ray photons (with energy up to 5 MeV) and twofold increase of hard x-ray yield in the energy range above 100 keV with intensity of the main pulse about 31018 W/cm2 and optimal parameters of the laser pre-pulse.