Powerful laser-produced quasi-half-cycle THz pulses.

The Maxwell equations-based 3D-analytical solution for the terahertz (THz) half-cycle electromagnetic wave transition radiation pulse has been found. This solution describes generation and propagation of transition radiation into free space from laser-produced relativistic electron bunch which crosses a target-vacuum interface as a result of ultrashort laser pulse interaction with a thin high-conductivity target. The analytical solution found complements the theory of laser initiated transition radiation.

Electron energization dynamics in interaction of self-generated magnetic vortices in upstream of collisionless electron/ion shocks.

Relativistic collisionless shocks are considered responsible for particle energization mechanisms leading to particle acceleration. While electron energization in shock front region of electron/ion collisionless shocks are the most studied, the mechanism of electron energization in interaction with self-generated magnetic vortices (MVs) in the upstream region is still unclear. We investigate electron energization mechanism in the upstream region of electron/ion relativistic collisionless shocks, using two dimensional particle-in-cell (PIC) simulations.

Bright synchrotron radiation from relativistic self-trapping of a short laser pulse in near-critical density plasma.

In a dense gas plasma a short laser pulse propagates in a relativistic self-trapping mode, which enables the effective conversion of laser energy to the accelerated electrons. This regime sustains effective loading which maximizes the total charge of the accelerating electrons, that provides a large amount of betatron radiation. The three-dimensional particle-in-cell simulations demonstrate how such a regime triggers x-ray generation with 0.

Ultrafast target charging due to polarization triggered by laser-accelerated electrons.

A significant step has been made towards understanding the physics of the transient surface current triggered by ejected electrons during the interaction of a short intense laser pulse with a high-conductivity target. Unlike the commonly discussed hypothesis of neutralization current generation as a result of the fast loss of hot electrons to the vacuum, the proposed mechanism is associated with excitation of the fast current by electric polarization due to transition radiation triggered by ejected electrons. We present a corresponding theoretical model and compare it with two simulation models using the finite-difference time-domain and particle-in-cell methods.

Bunching of light ions driven by heavy-ion front in multispecies ion beam accelerated by laser.

Deeply modulated ion spectra from contaminants present on the target surface were measured at the interaction of ultraintense (2-5)×10^{20}W/cm^{2} and high-contrast laser pulses (≲10^{-10}) with thin (∼μm) and ultrathin (∼nm) targets. This phenomenon, observed over a wide range of laser and target parameters, suggests that it is a generic feature of multispecies ion acceleration at high laser pulse contrast. The modulation is ascribed to the acceleration of various ion species at the rear of the target with steplike density profiles which provide well-separated ion species in the accelerated beam.