Ensemble of ultra-high intensity attosecond pulses from laser-plasma interaction

The efficient generation of intense X-rays and $\gamma$-radiation is studied. The scheme is based on the relativistic mirror concept, {\it i.e.}, a flying thin plasma slab interacts with a counterpropagating laser pulse, reflecting part of it in the form of an intense ultra-short electromagnetic pulse having an up-shifted frequency. In the proposed scheme a series of relativistic mirrors is generated in the interaction of the intense laser with a thin foil target as the pulse tears off and accelerates thin electron layers. A counterpropagating pulse is reflected by these flying layers in the form of an ensemble of ultra-short pulses resulting in a significant energy gain of the reflected radiation due to the momentum transfer from flying layers.Comment: 6 pages, 2 figures. Phys. Lett. A, in pres

Laser-based ion sources for medical applications

Interaction of relativistic short laser pulses with thin foils is studied by using 3D PIC simulations in the context of ICAN's “dream laser”. It is shown that such a laser will make it possible to accelerate protons and deuterons to multi-MeV energies with a current density of 100 A/cm2. The laser-triggered hadron beams may trigger nuclear reactions of interest for nuclear medicine and pharmacy. As an example, the yields C-11 for PET, of Tc-99m for SPECT, and neutrons for therapy have been analyzed

Channeling of relativistic laser pulses in underdense plasmas and subsequent electron acceleration

This contribution is concerned with the nonlinear behavior of a relativistic laser pulse focused in an underdense plasma and with the subsequent generation of fast electrons. Specifically, we study the interaction of laser pulses having their intensity Iλ2 in the range [1019, 1020]  W/cm2  μm2, focused in a plasma of electron density n0 such that the ratio n0/nc lies in the interval [10−3, 2 × 10−2], nc denoting the critical density; the laser pulse power PL exceeds the critical power for laser channeling Pch. The laser-plasma interaction in such conditions is investigated by means of 3D Particle in Cell (PIC) simulations. It is observed that the laser front gives rise to the excitation of a surface wave which propagates along the sharp boundaries of the electron free channel created by the laser pulse. The mechanism responsible for the generation of the fast electrons observed in the PIC simulations is then analyzed by means of a test particles code. It is thus found that the fast electrons are generated by the combination of the betatron process and of the acceleration by the surface wave. The maximum electron energy observed in the simulations with Iλ2 = 1020  W/cm2  μm2 and n0/nc = 2 × 10−2 is 350 MeV

Characteristics of bright betatron radiation from relativistic self-trapping of a short laser pulse in near-critical density plasma

International audienc

Stochastic simulation of the nonlinear kinetic equation with high-frequency electromagnetic fields

A general approach to Monte Carlo methods for Coulomb collisions is proposed. Its key idea is an approximation of Landau-Fokker-Planck (LFP) equations by Boltzmann equations of quasi-Maxwellian kind. Highfrequency fields are included into consideration and comparison with the well-known results are given.Запропоновано загальний підхід до моделювання кулонівських зіткнень методом Монте-Карло. Основна ідея полягає в апроксимації системи рівнянь Ландау-Фоккера-Планка (ОФП) рівняннями Больцмана квазі- максвеллiвського виду. Також розглядаються високочастотні поля, і наводиться порівняння з отриманими раніше результатами.Предложен общий подход к моделированию кулоновских столкновений методом Монте-Карло. Основная идея заключается в аппроксимации системы уравнений Ландау-Фоккера-Планка (ЛФП) уравнениями Больцмана квазимаксвелловского вида. Также рассматриваются высокочастотные поля, и приводится сравнение с полученными ранее результатами

Anomalous transmission of high contrast relativistically intense short pulses through thin metal foils

The frequency doubled laser pulses from the T3 laser system at the Center for Ultrafast Optical Science of the University Michigan$^{1}$ (with energy up to 1 J, a pulse duration of 400 fs, the wavelength is 0.53 ${\rm \mu}$m and the maximum intensity is $2.7\times 10^{19}$ W/cm$^{2})$ has been used to measure the light transmitted through thin metal targets. The intensity contrast ratio of the laser pulse was better than 10$^{ - 9}$ which is low enough to suggest the interaction with solid density plasma without preplasma. We observed the transmittance of the laser pulse through the aluminum foil with thickness up to 4 ${\rm \mu}$m and found that this radiation is polarized and centered at 0.53 ${\rm \mu}$m. We found that for 0.8 ${\rm \mu}$m thick foils the transmission was anomalously high (${\sim}10^{ - 2}$ %) and can't be explained by the skin effect for relativistic pulse