Laser-Target Experiments at PALS for Deuterium Plasma Beam Fusion

J. Krásaa, D. Klírb, J. Cikhardtb, c, M. Pfeifera, c, H. Horad, e, M. Krupkaa, c, f, K. Řezáčb, R. Dudžáka, c, J. Dostála, c, T. Buriana, c, M. Krůsc, J. Skálaa, K. Jungwirtha, Z. Rusiniakg, T. Pisarczykg, T. Chodukowskig aInstitute of Physics of the Czech Academy of Sciences, Prague, Czechia bFaculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czechia cInstitute of Plasma Physics of the Czech Academy of Sciences, Prague, Czechia dHB11 Energy P/L, 11 Wyndora Ave., Freshwater, NSW 2096, Australia eDepartment of Theoretical Physics, University of NSW, Sydney, Australia fFaculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czechia gInstitute of Plasma Physics and Laser Microfusion, Warsaw, Poland

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The Prague Asterix Laser System (PALS) is a terawatt iodine laser (1.2 kJ, 350 ps, 1315 nm), designed to deliver irradiance on target of about 3×1016 W/cm2. The PALS laser together with a Ti:sapphire laser (1 J, 50 fs, 800 nm) is used for experiments allowing femtosecond probing of laser-produced plasma. We present an experimental study of emission of hot electrons, fast ions and fusion neutrons generated through the 2H(d;n)3He fusion reaction of deuterons. During the laser-plasma interaction and plasma expansion, a multi-population of electrons appears. Non-isotropic emission of fast as well as thermal electrons is typical for the interaction of nanosecond laser radiation with plasma. The production of relativistic electrons makes it possible to accelerate protons to MeV energy and generate fusion neutrons via fusion reactions. The DD-neutron yield is compared to yields obtained from other experiments. Depending on the energy of the laser pulse, it is shown that the competition of laser contrast and laser pulse intensity sets a fundamental constraint on the ion emission and the resultant neutron yield performance of deuterated targets.

DOI:10.12693/APhysPolA.138.579 topics: laser-plasma acceleration of electrons and ions, self-focussing in plasmas, neutrons\\vs*{-5pt}