Effects of laser prepulses on laser-induced proton generation Article - Avril 2010

D. Batani, R. Jafer, Mina Veltcheva, R. Dezulian, Olle Lundh, F. Lindau, A. Persson, K. Osvay, C.G Wahlstrom, D. Carroll, P. Mckenna, Alessandro Flacco, Victor Malka

D. Batani, R. Jafer, Mina Veltcheva, R. Dezulian, Olle Lundh, F. Lindau, A. Persson, K. Osvay, C.G Wahlstrom, D. Carroll, P. Mckenna, Alessandro Flacco, Victor Malka, « Effects of laser prepulses on laser-induced proton generation  », New Journal of Physics, avril 2010, p. 045018. ISSN 1367-2630

Abstract

Low-intensity laser prepulses (<1013 W cm−2, nanosecond duration) are a major issue in experiments on laser-induced generation of protons, often limiting the performances of proton sources produced by high-intensity lasers (≈1019 W cm−2, picosecond or femtosecond duration). Depending on the intensity regime, several effects may be associated with the prepulse, some of which are discussed in this paper : (i) destruction of thin foil targets by the shock generated by the laser prepulse ; (ii) creation of preplasma on the target front side affecting laser absorption ; (iii) deformation of the target rear side ; and (iv) whole displacement of thin foil targets affecting the focusing condition. In particular, we show that under oblique high-intensity irradiation and for low prepulse intensities, the proton beam is directed away from the target normal. Deviation is towards the laser forward direction, with an angle that increases with the level and duration of the ASE pedestal. Also, for a given laser pulse, the beam deviation increases with proton energy. The observations are discussed in terms of target normal sheath acceleration, in combination with a laser-controllable shock wave locally deforming the target surface.

Voir la notice complète sur HAL

Actualités