Relaxation of spin-polarized low-density electron gas

Abstract: We derive the relaxation time of the total spin polarization for a low–density spin–polarized gas of fermions (electrons). This calculation is based on previously obtained collision operator in kinetic equation. This collision operator takes into consideration the spin component of interacting particles. As a side result we obtained the optical theorem, corresponding to the collision operator. Wherein we used the global symmetries in the mutual scattering amplitudes of two electrons. The result obtained is viable even in the case of relatively cold low–density spin–polarized plasma. The final result is obtained under assumption of small summary spin–polarization of fermions.Note: Research direction:Mathematical modelling in actual problems of science and technic

A study of electrical discharge in polyacetal capillary

A fast electrical discharge, created in an initially evacuated polyacetal capillary, has been simulated and realized. Steady state discharge parameters for polyethylene and polyacetal have been compared on the basis of the IONMIX code results. Space-time dependencies of plasma electron temperatures and densities under various experimental conditions have been judged on the basis of one-dimensional MHD model. Measured and evaluated macroscopic parameters correspond to each other

Influence of a radial electrical field on implosion of wire array

The effect of polarity on implosion of wire liners on the Angara-5-1 facility has been investigated. The electrode configuration provided creation of a radial electric field of up to 5000 kV/cm and of different direction on various sections of initial wires. The plasma production process was found to proceed in a distinctive manner in the wire sections where the radial electric field has different direction. The polarity effect at implosion of the wire liners on the Angara-5-1 facility becomes notable at increasing the rate of rising the electric field strength

Active Plasma Lensing for Relativistic Laser-Plasma-Accelerated Electron Beams

Compact, tunable, radially symmetric focusing of electrons is critical to laser-plasma accelerator (LPA) applications. Experiments are presented demonstrating the use of a discharge-capillary active plasma lens to focus 100-MeV-level LPA beams. The lens can provide tunable field gradients in excess of 3000  T/m, enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based electron beams and light sources to maintain their compact footprint. For a range of lens strengths, excellent agreement with simulation was obtained

Simulations of plasma channel formation by knife-like nanosecond laser beam

Abstract: The results of the simulations performed in KIAM are presented. Formation of channels in gas targets using a ns-laser is considered in relevant regimes: output energy hundreds of Joules, nanosecond duration laser pulse, from 1 to 10 petawatt main laser pulse power. Such a kind of experiments are planned in the European laser center ELI-Beamline. They will develop a laser induced method of relativistic electrons acceleration, based on ideas investigated previously in NLBL. The magnetohydrodynamic codes NPINCH and MARPLE are used for 1D and 2D simulations of plasma channel formation in the region of elongated focus of knife-like nanosecond laser beam in under-critical gas density. Such plasma channel can be applied for transportation of high power femtosecond laser beams over large distances. The 2D simulations are performed to investigate the process of symmetrization of the channel, when the asymmetry of initial channel is caused by asymmetric deposition of the laser energy due to spatial structure of a plane focus of the laser beam. The simulations show how to reach the regimes of symmetric plasma channel formation. With 1D simulations the parameters of plasma channels for various cases under the condition of channel symmetrization are obtained.Note: Research direction:Mathematical modelling in actual problems of science and technic