arXiv subjects

A. Bashinov

Publications and source records attributed to A. Bashinov.

6 recordsLinked to original sources

arXiv2024

Dynamics of radiating particles in current sheets with a transverse magnetic field component

Upcoming multipetawatt laser facilities are capable of inducing effects of quantum electrodynamics (QED) in laser-plasma interaction such as strong radiation reaction and QED cascades, both of which can significantly influence the properties and dynamics of laser plasma. This can result in the formation of extreme plasma structures with unprecedented TG levels of quasistatic magnetic fields, for example current sheets or pinch configurations of nanometer scale or smaller. In such structures radiation losses can play a significant role, so the influence of radiation losses onto the evolution of extreme current sheets deserves a separate and thorough investigation. In the current work we develop an analytical model and extend the quasiadiabatic approach describing individual particle motion onto 3D particle motion in the case when radiation reaction is non-negligible. Given that particle motion is determined by (quasi)invariants of non-dissipative motion, we derive how these (quasi)invariants evolve under the influence of radiation losses, quantify this influence and obtain a (quasi)invariant of dissipative motion. This allows reducing the dimensionality of the system of differential equations describing particle motion to just two instead of six. It is also discussed how the presented method can be used in a wider range of problems.

physics.plasm-ph↗

arXiv2021

Particle dynamics governed by radiation losses in extreme-field current sheets

Particles moving in current sheets under extreme conditions, such as those in the vicinity of pulsars or those predicted on upcoming multipetawatt laser facilities, may be subject to significant radiation losses. We present an analysis of particle motion in fields of a relativistic neutral electron-positron current sheet in the case when radiative effects must be accounted for. In the Landau-Lifshitz radiation reaction force model, when quantum effects are negligible, an analytical solution for particle trajectories is derived. Based on this solution, for the case when quantum effects are significant an averaged quantum solution in the semiclassical approach is obtained. The applicability region of the solutions is determined and analytical trajectories are found to be in good agreement with those of numerical simulations with account for radiative effects. Based on these results we gain new insights into current sheet phenomena expected on upcoming laser facilities.

physics.plasm-ph↗

arXiv2020

Strategies for particle resampling in PIC simulations

In particle-in-cell simulations, excessive or even unfeasible computational demands can be caused by the growth of the number of particles in the course of prolific ionization or cascaded pair production due to the effects of quantum electrodynamics. Here we discuss how one can organize a dynamic rearrangement of the ensemble to reduce the number of macroparticles, while maintaining acceptable sampling of an arbitrary particle distribution. The approaches of merging and thinning as well as their variants are discussed and the aspects of use are considered.

physics.comp-ph↗

arXiv2020

Optimized routines for event generators in QED-PIC codes

In recent years, the prospects of performing fundamental and applied studies at the next-generation high-intensity laser facilities have greatly stimulated the interest in performing large-scale simulations of laser interaction with matter with the account for quantum electrodynamics (QED) processes such as emission of high energy photons and decay of such photons into electron-positron pairs. These processes can be modeled via probabilistic routines that include frequent computation of synchrotron functions and can constitute significant computational demands within accordingly extended Particle-in-Cell (QED-PIC) algorithms. In this regard, the optimization of these routines is of great interest. In this paper, we propose and describe two modifications. First, we derive a more accurate upper-bound estimate for the rate of QED events and use it to arrange local sub-stepping of the global time step in a significantly more efficient way than done previously. Second, we present a new high-performance implementation of synchrotron functions. Our optimizations made it possible to speed up the computations by a factor of up to 13.7 depending on the problem. Our implementation is integrated into the PICADOR and Hi-Chi codes, the latter of which is distributed publicly (https://github.com/hi-chi/pyHiChi).

physics.comp-ph↗

arXiv2016

Ultra-bright GeV photon source via controlled electromagnetic cascades in laser-dipole waves

One aim of upcoming high-intensity laser facilities is to provide new high-flux gamma-ray sources. Electromagnetic cascades may serve for this, but are known to limit both field strengths and particle energies, restricting efficient production of photons to sub-GeV energies. Here we show how to create a directed GeV photon source, enabled by a controlled interplay between the cascade and anomalous radiative trapping. Using advanced 3D QED particle-in-cell (PIC) simulations and analytic estimates, we show that the concept is feasible for planned peak powers of 10 PW level. A higher peak power of 40 PW can provide $10^9$ photons with GeV energies in a well-collimated 3 fs beam, achieving peak brilliance ${9 \times 10^{24}}$ ph s$^{-1}$mrad$^{-2}$mm$^{-2}$/0.1${\%}$BW. Such a source would be a powerful tool for studying fundamental electromagnetic and nuclear processes.

physics.plasm-ph↗

arXiv2013

Anomalous radiative trapping in laser fields of extreme intensity

We demonstrate that charged particles in a sufficiently intense standing wave are compressed toward, and oscillate synchronously at, the maxima of the electric field. This unusual trapping behaviour, which we call 'anomalous radiative trapping' (ART), opens up new possibilities for the generation of radiation and particle beams, both of which are high-energy, directed and collimated. ART also provides a mechanism for particle control in high-intensity QED experiments.

physics.plasm-ph↗