Propagation of Super-intense and Ultra-short Laser Pulses in Plasmas

AbstractThe propagation of super-intense and ultra-short laser pulses in plasmas is a main concern in several applications of the laser-plasma interactions, from Inertial Confinement Fusion (ICF) to High Energy Physics (HEP). During the propagation in the plasma the light beam deeply changes its parameters due the onset of non-linear effects, among them the relativistic regime of the electron quivering motion. These extreme conditions are suitable for the electron acceleration in high field gradient, opening the way for the realization of compact secondary sources of X-gamma rays

The particle laser-plasma acceleration in Italy

In this paper the beginning activity on Laser Plasma Acceleration in Italy and the recent results obtained in the frame of the INFN Strategic Project PLASMONX will be presented. The project, involving eight groups and two National Laboratory disseminated along Italy, is aimed at the development of an innovative, high-gradient acceleration with super- intense and ultra-short laser pulses, and a tuneable, hard X/-ray source, based upon Thomson scattering of optical photons by energetic electrons. Both experiments require very high power, ultra-short laser pulses in combination with very bright and short electron bunches generated either by conventional acceleration (LINAC) or by laser-driven acceleration in plasmas

Guest Editorial

This issue of Laser and Particle Beams contains a selection of papers presented at the International Workshop on Laser and Plasma Accelerators held at Portovenere, Italy, from September 29 to October 3, 2003. The papers were subjected to the regular refereeing procedure, in conformity with the publication standards concerning originality and quality of presentation for articles in this journal. The papers published here do not cover the full workshop program and therefore do not constitute proceedings in the normal sense. The Workshop was the last in a series sponsored by the International Committee for Future Accelerators to promote international collaboration in the study, development, and exploitation of advanced and novel accelerators

The physics of the laser-plasma accelerators: Challenges and limits

To meet the challenge of future accelerators based on the laserplasma techniques new experimental schemes have to be investigated and a strategy on the laser technology to get ultra-high peak power as well as very high average power formulated. Top-level laser requirements for potential laser-based accelerator applications will be needed and the major limits to the electron energy gain have to be overcome, including laser pulse diffraction, electron dephasing and laser pulse energy depletion. A viable alternative to the multi-stage acceleration scheme could be a greater control of the laser pulse evolution in the underdense plasma that could inhibit filamentation and other detrimental instabilities as Raman and self-phase modulation enabling the full exploitation of the laser guiding over several Rayleigh lengths. A brief overview will be given of those aspects of laser plasma acceleration leading to a completely new generation of compact sources of energetic particles. In particular, a simplified introduction to the field of electron laser wakefield acceleration will be first given and some recent experiments reported

High brightness laser-plasma X-ray source at IFAM : Characterization and applications

A high brightness laser-plasma X-ray source has been set-up and is presently available at IFAM. A wide range of diagnostics has been set up to monitor the properties of the X-ray radiation and to control the main parameters including photon energy, flux intensity, and pulse duration. A beam extractor enables access to the X-ray radiation at atmospheric pressure. A simple, easy-to-use projection microscope has been built which is capable of single-shot micron resolution imaging with digital acquisition. Preliminary biomedical experiments show that the X-ray doses available on a single laser shot exposure of our source fully meet the conditions required for an important class of biological experiments based on X-ray induced DNA damage providing an ideal alternative to the long time exposures needed with X-ray tubes

Preface to "Oscillator-Amplifier Free Electron Lasers an Outlook to Their Feasibility and Performances"

Free Electron Lasers (FELs) are certainly among the most interesting devices, belonging to the realm of coherent radiation sources [...

The laser-matter interaction meets the high energy physics: Laser-plasma accelerators and bright X/gamma-ray sources

Laser matter interaction in the regime of super-intense and ultra-short laser pulses is discovering common interests and goals for plasma and elementary particles physics. Among them, the electron laser wakefield acceleration and the X/γ tunable sources, based on the Thomson scattering (TS) of optical photons on accelerated electrons, represent the most challenging applications. The activity of the Intense Laser Irradiation Laboratory in this field will be presented

Line spectroscopy with spatial resolution of laser-plasma X-ray emission

High dynamic range, space-resolved X-ray spectra of an aluminum laser–plasma in the 5.5–8 Å range were obtained using a TlAP crystal and a cooled CCD camera as a detector. This technique was used to investigate the emission region in the longitudinal direction over a distance of approximately 350 μm from the solid target surface. These data show that the electron density profile varies by two orders of magnitude with the temperature ranging from about 180 eV in the overdense region to about 650 eV in the underdense region. Accordingly, different equilibria take place across the explored region which can be identified with this experimental technique. Detailed studies on highly ionized atomic species in different plasma conditions can therefore be performed simultaneously under controlled conditions

Experimental study of picosecond laser plasma formation in thin foils

A high performance, fully controlled picosecond laser system has been designed and built with the aid of a numerical code capable of simulating the temporal behavior of the laser system, including each active and passive component. The laser performance was characterized with an optical streak camera, equivalent plane monitor, and calorimeter measurements. The laser pulse was focused on 150-nm thick foils to investigate plasma formation and the related transmittivity of the laser light. The experimental data are in very good agreement with the predictions of a simple, 2D analytical model that takes into account the actual shot-to-shot features of the laser pulse. The temporal profile of the pulse and the intensity distribution in the focal spot were found to play a key role in determining the transmission properties of the laser-irradiated foil. This work may be relevant to a wide class of laser exploded foil plasma experiments

Ray-tracing simulations of a bent crystal X-ray optics for imaging using laser-plasma X-ray sources

Ray-tracing simulations of an optical X-ray system based on a spherically bent crystal operating in Bragg configuration for monochromatic projection imaging of thin samples are presented, obtained using a code developed for that purpose. The code is particularly suited for characterizing experimental arrangements routinely used with laser-produced plasma X-ray sources. In particular, the spatial resolution of the imaging system was investigated and a careful study of the complex pattern of the X-ray backlighting beam was performed