Multi-energy ion implantation from high-intensity laser

Abstract The laser-matter interaction using nominal laser intensity above 1015 W/cm2 generates in vacuum non-equilibrium plasmas accelerating ions at energies from tens keV up to hundreds MeV. From thin targets, using the TNSA regime, plasma is generated in the forward direction accelerating ions above 1 MeV per charge state and inducing high-ionization states. Generally, the ion energies follow a Boltzmann-like distribution characterized by a cutoff at high energy and by a Coulomb-shift towards high energy increasing the ion charge state. The accelerated ions are emitted with the high directivity, depending on the ion charge state and ion mass, along the normal to the target surface. The ion fluencies depend on the ablated mass by laser, indeed it is low for thin targets. Ions accelerated from plasma can be implanted on different substrates such as Si crystals, glassy-carbon and polymers at different fluences. The ion dose increment of implanted substrates is obtainable with repetitive laser shots and with repetitive plasma emissions. Ion beam analytical methods (IBA), such as Rutherford backscattering spectroscopy (RBS), elastic recoil detection analysis (ERDA) and proton-induced X-ray emission (PIXE) can be employed to analyse the implanted species in the substrates. Such analyses represent 'off-line' methods to extrapolate and to character the plasma ion stream emission as well as to investigate the chemical and physical modifications of the implanted surface. The multi-energy and species ion implantation from plasma, at high fluency, changes the physical and chemical properties of the implanted substrates, in fact, many parameters, such as morphology, hardness, optical and mechanical properties, wetting ability and nanostructure generation may be modified through the thermal-assisted implantation by multi-energy ions from laser-generated plasma

Shock dynamics induced by double-spot laser irradiation of layered targets

We studied the interaction of a double-spot laser beam with targets using the Prague Asterix Laser System (PALS) iodine laser working at 0.44 μm wavelength and intensity of about 1015 W/cm2. Shock breakout signals were recorder using time-resolved self-emission from target rear side of irradiated targets. We compared the behavior of pure Al targets and of targets with a foam layer on the laser side. Results have been simulated using hydrodynamic numerical codes

High-current stream of energetic α particles from laser-driven proton-boron fusion

The nuclear reaction known as proton-boron fusion has been triggered by a subnanosecond laser system focused onto a thick boron nitride target at modest laser intensity (∼10 16 W/cm2), resulting in a record yield of generated α particles. The estimated value of α particles emitted per laser pulse is around 10 11, thus orders of magnitude higher than any other experimental result previously reported. The accelerated α-particle stream shows unique features in terms of kinetic energy (up to 10 MeV), pulse duration (∼10 ns), and peak current (∼2 A) at 1 m from the source, promising potential applications of such neutronless nuclear fusion reactions. We have used a beam-driven fusion scheme to explain the total number of α particles generated in the nuclear reaction. In this model, protons accelerated inside the plasma, moving forward into the bulk of the target, can interact with 11 B atoms, thus efficiently triggering fusion reactions. An overview of literature results obtained with different laser parameters, experimental setups, and target compositions is reported and discussed

Dataset for "Magnetic field generation using single-plate targets driven by kJ-ns class laser"

Dataset underpinning the results presented in the article titled, "Magnetic field generation using single-plate targets driven by kJ-ns class laser" published in Plasma Physics Controlled Fusion (2020) Abstract of the paper: Strong magnetic fields of upto 20 T, corresponding to a current of tens of kA were produced in a coil connected to a single-plate of cm2 area irradiated by a kJ-ns laser pulse. The use of such macroscopic plates protects the coil from plasma debris, while maintaining a strong magnetic field for a time-scale much longer than the laser pulse duration. By correlating the measured magnetic field in the coil to the number of electrons emitted from the interaction zone, we deduce that the target capacitance is enhanced by two orders of magnitude because of the plasma sheath in the proximity of the focal spot. Particle-in-cell simulations illustrate the dynamics of sheath potential and current flow through the coil to ground, thus closing the circuit due to the escape of laser-produced hot electrons from the target