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Enhanced X-ray generation and hot electron acceleration at high contrast relativistic laser interaction with sub-wavelength scale structured targetsтезисы доклада Тезисы
- Авторы: Ivanov K.A., Gozhev D., Makarov S., Ageev E., Borisenko L., Danilov P., Kudryashov S., Brantov A., Savel’ev A.B.
- Сборник: Book of abstracts of the Conference on High Intensity Lasers and Attosecond Science in Israel (CHILI2016)
- Тезисы
- Год издания: 2016
- Аннотация: In this work we present our recent experimental results on slightly relativistic high contrast laser pulse interaction with structured at wavelength scale solid targets. The modifications with different shapes (cones, bubbles, etc) were made by laser ablation of metals with fluence slightly exceeding the damage threshold and additional etching in sulfuric acid solution to form the pattern of sharpened structures with a period and size from ~0.1 to ~20 micrometers. In our experiments we used Ti:Sa radiation (up to 50 mJ, 50 fs, 10Hz) with two different picoseconds contrasts: ASE pedestal contrast ratio 108 ~10 ps prior to main pulse or >1010 with the use of XPW contrast cleaner. The radiation was focused onto the surface of the targets to a peak intensity around 2-4x1018 W/cm2. For comparison we also made experiments with initially flat target. We found that the contrast of the pulse plays a crucial role in the efficiency of particles acceleration and X-ray generation. It is demonstrated, that the hot electron temperature is significantly increased (from ~150 to almost 500 keV), when the sub-wavelength structured target is used, compared to a flat one for a high contrast laser radiation. The concentration of the structures in the focal spot is also found to be important – the electron energy gain grows up, when the number of encountered into the interaction area modifications is increased. The effect is much less pronounced if the pulse with moderate contrast (without XPW) is applied, indicating the role of high contrast in preserving the structures from damaging by the ASE and prepulses before the main pulse arrival. The PIC simulation revealed the efficient acceleration of particles to high energies in the complex field formed on the edges of the structures. The effect may be related to the enhanced laser absorption, local electric field amplification, quasistatic surface field formation and other phenomena. This work was supported by the RFBR grant #15-02-08113-a.
- Добавил в систему: Иванов Константин Анатольевич