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Preplasma effect on the hot electron generation at the action of sub-relativistic laser pulse onto the surface of solid targetsтезисы доклада
- Авторы: Ivanov K.A., Shulyapov S.A., Larkin A.S., Uryupina D.S., Savel’ev A.B., Volkov R.V., Brantov A.V., Bychenkov V.Yu
- Сборник: Book of abstract EMMI Workshop High energy density plasma diagnostic at FAIR
- Тезисы
- Год издания: 2013
- Место издания: GSI Darmstadt
- Первая страница: 63
- Последняя страница: 63
- Аннотация: We present our recent results on diagnostics of the plasma, created by a sub-relativistic femtosecond laser pulse onto the surface of solid targets (metals and dielectric) with varied initial plasma density scalelength. We have shown that the preplasma plays a significant role in hot electron acceleration process. In our experiments we used a laser pulse delivered by the Ti:Sa laser system (pulse duration – 40 fs, energy on target – up to 50 mJ, wavelength – 800 nm, repetition rate – 10 Hz, peak intensity – up to 5x10^18 W/cm^2). The preplasma was formed by introducing a prepulse with varied duration, energy and delay (by decreasing the contrast of the laser pulse or by using an additional Nd:YAG laser). The appearance of high energetic hot electron component with the temperature up to a few hundreds of keV is observed for the case of a long scale warm preplasma. The effect may be connected with the self-focusing of laser pulse in the preplasma and with the growth of parametric instabilities near ¼ critical density (two-plasmon decay and Raman scattering) leading to the generation of hot particles. We have also observed the appreciable amplification of the hot electron temperature when the duration of the laser pulse was increased from 40 to a few hundreds of femtoseconds with constant fluence for metal targets with a large preplasma. The effect is not observed at the sharp plasma boundary and for the high ablation threshold material (SiO2), when the preplasma cloud is much smaller by comparing to metal targets. The experimental results are supported by PIC simulations and optical shadowgraphy of preplasma.
- Добавил в систему: Иванов Константин Анатольевич