Production of relativistic electrons, MeV deuterons and protons by sub-nanosecond terawatt laser

Abstract

By the use of various experimental techniques, it is shown that the relativistic electrons, MeV protons, and deuterons are emitted from a 500-μm thick (CD2)n target exposed to Iλ2 ≈ 5 × 1016 W cm–2 μm2, which is delivered by the iodine photodissociation laser Prague Asterix Laser System. A parameter reflecting the laser-power efficiency of the proton acceleration is used for comparison of the observed maximum proton energy with data from other experiments. The number of protons and deuterons constituting the backward and forward jets is estimated. Values of maximum proton energies and electron temperatures indicate that the laser intensity should reach a relativistic level through the laser beam self-focusing. The occurrence of electron bunches in front of the irradiated target surface was identified by time resolved femtosecond interferometry. Energy distribution functions of electrons emitted in the both backward and forward directions are analysed and compared.