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Amplified hard X-ray emission and hot electron generation at high intensity femtosecond laser-plasma interaction utilizing laser induced nano-structured targetsтезисы доклада Тезисы
- Авторы: Ivanov K.A., Makarov S., Danilov P., Saraeva I., Kudryashov S., Brantov A., Volkov R., Gozhev D., Savel’ev A.B.
- Сборник: Book of abstracts of the International Symposium “Fundamentals of Laser Assisted Micro-and Nanotechnologies” (FLAMN-16)
- Тезисы
- Год издания: 2016
- Место издания: Санкт-Петербург
- Аннотация: The recent results of experimental and numerical investigation of relativistic femtosecond laser-plasma interaction are presented. We show that the efficiency of hard X-ray generation and hot electron acceleration may be significantly increased if sub-wavelength scale structured targets are used. The modified targets were made by the laser ablation (fluence slightly over damage threshold) of solids (metals and dielectrics). Varying the regime of interaction and by additional etching in acid solution the periodic structures with different shapes (cones, bubbles, etc) and size (from ~0.1 to ~20 micrometers) could be formed. This method allows creating large area sample, suitable for high repetition rate laser-plasma experiments. The hot plasma was formed by the irradiation of samples by the Ti:Sa laser pulses (=50 fs, E>10 mJ, 10 Hz, Ipeak>1018 W/cm2). We found that the femtosecond damage threshold of structured targets is one order of magnitude lower, than for initial flat material. Hence the high contrast laser pulses must be used. It is demonstrated, that the hot electron temperature is significantly increased (from ~150 to almost 500 keV) and fourfold growth of hard X-ray emission is observed, when the sub-wavelength structured target is used, compared to a flat one with the use of high contrast laser radiation (ASE pedestal contrast ration ~1010 ten ps prior to main pulse with the use of XPW contrast cleaner). The energy grow effect is much less pronounced if the pulse with moderate contrast (~108 ration) is applied. This shows the role of high contrast in preserving the modifications from damaging before the main pulse arrival. The PIC simulation revealed that the observed effect of hot particles generation may be related to the acceleration of electrons in the complex field formed on the edges of the structures. This work was supported by the RFBR grant #15-02-08113-a.
- Добавил в систему: Иванов Константин Анатольевич