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The interaction of high-intensity laser pulses with matter releases instantaneously ultra-large currents of highly energetic electrons, leading to the generation of highly-transient, large-amplitude electric and magnetic fields. We report results of recent experiment in which such phenomena have been studied by using proton probing techniques able to provide maps of the electrostatic fields with high spatial and temporal resolution. The dynamics of ponderomotive channelling in underdense plasmas have been studied with this technique, as also the process of Debye sheath formation and MeV ion front expansion at the rear of laser-irradiated thin metallic foils.

The acceleration of high-energy ion beams (up to several tens of MeV per nucleon) following the interaction of short (t<1ps) and intense (Iλ² > 10¹⁸W cm^-2μm²) laser pulses with solid targets has been one of the most active areas of research in the last few years. The exceptional properties of these beams (high brightness and high spectral cutoff, high directionality and laminarity, short burst duration) distinguish them from those of the lower energy ions accelerated in earlier experiments at moderate laser intensities. In view of these properties, laser-driven ion beams can be employed in a number of groundbreaking applications in the scientific, technological and medical areas. This paper reviews the current state-of-the-art, highlights recent developments and indicate future directions of this research area.

In recent experiments of laser pulse interaction at relativistic intensities with a low density plasma, the proton radiography technique showed evidence of long–lived field structures generated after the self–channeling of the laser pulse.

We present 2D particle-in-cell simulations of this interaction regime, where the dynamics of similar structures has been resolved with high temporal and spatial resolution. An axially symmetrical field pattern, resembling both soliton–like and vortex structures, has been observed. A study of the physics of such structures and a comparison with experimental data is in progress.

It is now a fact that focusing an intense ultra short laser pulse onto a gas jet or thin targets, generates energetic collimated electrons or ions forming ultra short beams of energies > 100 MeV. The different mechanisms to explain such laser accelerated electrons or ions will be discussed. Data obtained by recent experiments will be presented. We report the experiment planed to study laser accelerated ions and/or particles using picosecond and femtosecond high energy laser pulses focused to achieve intensities >10¹⁸ watts/cm². The design of the interaction chamber and the choice of targets as well as the ultra fast detection techniques will be speculated. This source of accelerated ions having unique properties is expected to become an interesting tool for many fields in physics, chemistry and biology. It can enable advances of devices to be used in medicine.