arXiv subjects

M. Lamač

Publications and source records attributed to M. Lamač.

3 recordsLinked to original sources

arXiv2026

Optimized matching conditions for self-guided laser wakefield accelerators

We revisit the matching conditions for self-guided laser pulse propagation in plasma and refine their formulation to maximize the energy of electrons produced via laser wakefield acceleration. Bayesian optimization, combined with particle-in-cell simulations carried out in a quasi-three-dimensional geometry and a Lorentz-boosted frame, is employed. The optimization identifies the maximum electron energy that a self-guided laser wakefield accelerator, driven by a laser of a given energy, can produce, together with the corresponding acceleration distance. Our results further demonstrate that electrons with energies close to the maximum value can be obtained across a relatively wide range of input parameters and without the need for their precise tuning. This provides substantial flexibility for experimental implementation and significantly relaxes the operational constraints associated with self-guided laser wakefield accelerators.

physics.plasm-ph↗

arXiv2025

Collimated $ γ$-flash emission along the target surface irradiated by a laser at non-grazing incidence

The interaction of a high-power laser with a solid target provides ways to produce beams of $γ$-photons. For normal incidence of the laser on the target the beams usually appear in a form of two lobes, which are symmetric with respect to the laser propagation axis. In this work we demonstrate via three-dimensional particle-in-cell simulations a regime where for oblique incidence the emission of a collimated $γ$-photon beam is in the direction parallel to the target surface. The process is ascribed to the interference pattern in the electromagnetic field formed by the incident and reflected laser pulse. The electromagnetic field accelerates electrons to the GeV energy level, while temporarily directing their momentum along the target surface. Consequently, they emit a collimated $γ$-photon beam in the same direction. The dependencies of $γ$-photon emission on the incident angle, laser pulse polarization, power and duration and target thickness and preplasma are also addressed in the paper. The beam directionality is important for designing future experiments. In addition, this setup causes the generation of high-order harmonics propagating along the target surface.

physics.plasm-ph↗

arXiv2022

Ultrafast hard X-ray sources based on Relativistic Electrons at ELI Beamlines

We report the LWFA driven X-ray sources development at ELI beamlines. ELI Gammatron beamline provides X-ray pulses of energies from 1-100 keV in betatron scheme, and up to a MeV in Compton scheme. A state-of-the-art Ti:Sa diode-pumped HAPLS laser (10-30 J, 30 fs @10 Hz) is used as a driving laser for these X-ray sources. These sources are characterized with a low divergence (< 10 mrad), small source size (few μm), short pulse duration (a few fs) and photon flux up to1010 photons per pulse. In addition, a separate Betatron X-ray source is being developed in the ELI Plasma Physics Platform (P3)that will serve as an active diagnostics of various plasma physics experiments. P3 is dedicated to laboratory astrophysics, HED physics, multi-beam experiments, warm dense matter and fundamental research. Besides the presentation of the two X-ray sources, we will also introduce a novel optical probing method with increased interferometric sensitivity for characterization of low-density gas jets. The sensitivity is achieved together with using a novel optical configuration employing multiple passes of the probe beam through the object and relay-imaging of the object between the individual passes, and a short probing beam (405 nm).

physics.plasm-ph↗