Ion acceleration from intense laser-generated plasma: methods, diagnostics and possible applications

Abstract

Abstract. Many parameters of non-equilibrium plasma generated by high intensity and fast lasers depend on the pulse intensity and the laser wavelength. In conditions favourable for the target normal sheath acceleration (TNSA) regime the ion acceleration from the rear side of the target can be enhanced by increasing the thin foil absorbance through the use of nanoparticles and nanostructures promoting the surface plasmon resonance effect. In conditions favourable for the backward plasma acceleration (BPA) regime, when thick targets are used, a special role is played by the laser focal position with respect to the target surface, a proper choice of which may result in induced self-focusing effects and non-linear acceleration enhancement. SiC detectors employed in the time-of-fl ight (TOF) confi guration and a Thomson parabola spectrometer permit on-line diagnostics of the ion streams emitted at high kinetic energies. The target composition and geometry, apart from the laser parameters and to the irradiation conditions, allow further control of the plasma characteristics and can be varied by using advanced targets to reach the maximum ion acceleration. Measurements using advanced targets with enhanced the laser absorption effect in thin fi lms are presented. Applications of accelerated ions in the fi eld of ion source, hadrontherapy and nuclear physics are discussed.

Graphite oxide based targets applied in laser matter interaction

“…In this step, in facts, it is generated a "non-equilibrium state of dense matter", consisting of hot electrons and cold ions, generating an electron cloud out of the target and a high positive target surface in which ion acceleration take place. The developed electric field, direct orthogonally to the target surface, is of the order of tens GV/m, as reported in literature [20]. …”

Physical investigations on the radiation damage of graphene oxide by IR pulsed laser

“…The laser irradiation of GO generates a plasma in front of the target emitting visible light, UV, soft X-rays, electrons and ions, as reported in previous investigations [9]. The different electron and ion mobility produces a non equilibrium plasma accelerating ions along the normal to the target surface.…”

Ion energy distributions from laser-generated plasmas at two different intensities

“…From interactions of laser with solid thin target, in high vacuum condition, it's possible to obtain energies in the order of keV at about 10 10 W/cm 2 , while using 10 20 W/cm 2 it is possible to reach energies of MeVs [1]. The most diffused regime to induce high ion acceleration, using sub-nanosecond laser pulses interacting with thin foils, it's known as Target Normal Sheath Acceleration (TNSA), in which the plasma is produced mainly in forward direction with high energy ions above 1 MeV per charge state [2].…”