arXiv subjects

Norbert Kroó

Publications and source records attributed to Norbert Kroó.

8 recordsLinked to original sources

arXiv2026

Directed Nano-antennas for Laser Fusion

Why do we use nano-antennas for fusion? In three sentences: The present laser induced fusion plans use extreme mechanical shock compression to get one hotspot and then ignition. Still fusion burning spreads slower than expansion, and mechanical instabilities may also develop. With nano-antennas in radiation dominated systems, simultaneous ignition can be achieved in the whole target volume and there is no time left for mechanical instabilities. Ignition is achieved with protons accelerated in the direction of the nanoantennas that are orthogonal to the direction of laser irradiation. Present laser fusion methods are based on extreme and slow mechanical compression with an ablator surface on the fuel target pellet to increase compression and eliminate penetration of laser electromagnetic energy into the target. This arises from a mistaken assumption, [1] that the detonation normal 4-vector should have vanishing time-like component, and this assumption eliminates the possibility to rapid or even simultaneous, radiation dominated detonations, (which are well known in the burning (or hadronization) of Quark Gluon Plasma).

physics.plasm-ph↗

arXiv2024

PIC simulations of laser-induced proton acceleration by resonant nanoantennas for fusion

Rapid recent development in laser technology and methods learned from relativistic heavy ion physics led to new possibilities for fusion. Using a Hydrogen rich UDMA-TEGDMA polymer fusion target, laser irradiation ionizes the target. If we implant nanoantennas into the target resonating to the laser light frequency massive number of electrons of the ionized plasma resonate within the nanoantenna forming a so called nanoplasmonic wave. Our kinetic model simulation with a Hydrogen target indicates that the field of these resonating electrons attracts and accelerates the surrounding protons of the plasma to multi-MeV energy. These protons are then energetic enough to achieve nuclear transmutation and fusion reactions. Without resonating nanoantenna there is no such collective proton acceleration, no energetic protons, and nuclear reactions at 30 mJ laser pulse energy.

physics.plasm-ph↗

arXiv2024

Plasmonic nanoprism distributions to promote enhanced and uniform energy deposition in passive and active targets

Passive and active targets, implanted with gold nanoprisms, were designed to achieve enhanced and uniform power absorption during two-sided illumination by short laser pulses. The target length was adjusted to match the short laser pulse-length. Capabilities of three different, uniform, single-peaked Gaussian and adjusted, nanoresonator number density distributions were compared. The average local E-field inside the gain medium and on the surface of the nanoprisms were mapped as a function of the pump E-field strength and dye concentration, assuming a uniform nanoresonator distribution. The optimal parameters were adopted to each inspected nanoprism distributions. The time-evolution of the near-field enhancement (NFE), integrated power-loss and deposited energy were determined, additionally, the time-evolution of the standard deviation of these quantities was monitored. A comparative study was performed on passive and active targets, to determine the most advantageous nanoprism number density distribution type and to consider the advantages of dye doping. Based on the results, the adjusted distribution is proposed both in passive and active targets. Doping with the dye is advantageous in every inspected distribution in decreasing the minimal standard deviation of the NFE. It is advantageous in decreasing the delay of the minimal standard deviation in the power-loss and deposited energy, the standard deviation of the NFE as well as in increasing the FOM of the NFE in the uniform and adjusted distributions. In addition, doping allows for decreasing the delay of the minimal standard deviation in the NFE / increasing the mean NFE / decreasing the standard deviation of the power-loss and deposited energy in the uniform / Gaussian / adjusted distribution.

physics.optics↗

arXiv2024

Raman spectroscopic characterization of crater walls formed upon single-shot high energy femtosecond laser irradiation of dimethacrylate polymer doped with plasmonic gold nanorods

The bonding configuration of the crater walls formed in urethane dimethacrylate-based polymer doped with plasmonic gold nanorods upon irradiation with a single-shot high-energy femtosecond laser pulse has been studied by Raman spectroscopy. New Raman bands were detected in the 2000-2500 cm-1 region of the Raman spectrum the intensities of which showed strong dependence on the concentration of the plasmonic nanoparticles and the energy of the laser pulse. Based on model calculations of the Raman frequencies of the polymer these peaks were attributed to carbon-deuterium and nitrogen-deuterium vibrations. Their appearance might indicate the occurrence of nuclear reactions in the polymer excited by the ultra-strong laser field amplified by the plasmonic nanoparticles.

physics.plasm-ph↗

arXiv2024

Pulsed laser intensity dependence of crater formation and light reflection in the UDMA-TEGDMA copolymer nanocomposite, doped with resonant plasmonic gold nanorods

Plasmonic nanoparticles embedded into a solid matrix could play crucial role in laser-matter interactions. In this study, excess energy creation was observed during the single-shot irradiation of a polymer matrix containing plasmonic gold nanorods, resonant to the laser wavelength, with a high intensity femtosecond laser pulse. This effect was manifested in a 7-fold rise in the crater volume for a 1.7-fold increase of the laser intensity, and was absent in the pure polymer without the gold doping. It occurred at laser intensities > 1.5 x 1017 W/cm2, being the vanishing threshold of plasma mirror formation, resulting in a more than 80% increase of the amount of laser light entering the target. This threshold was found to be critical for the plasmonic effect of gold nanoantennas tuned to the wavelength of the laser on the crater formation.

physics.optics↗

arXiv2022

Kinetic Model Evaluation of Dynamical Properties of Nanaorod Antennas Embedded in a Polymer Carrying the Nuclei of Fusion Fuel

Recently laser induced fusion with simultaneous volume ignition, a spin-off from relativistic heavy ion collisions, was proposed, where implanted nanoantennas regulated and amplified the light absorption in the fusion target. Studies of resilience of the nanoantennas was published recently in vacuum. These studies are extended to nanoantennas embedded into a polymer, which modifies the nanoantenna's lifetime and absorption properties.

physics.plasm-ph↗

arXiv2021

Laser Wake Field Collider

Recently NAano-Plasmonic, Laser Inertial Fusion Experiments (NAPLIFE) were proposed, as an improved way to achieve laser driven fusion. The improvement is the combination of two basic research discoveries: (i) The possibility of detonations on space-time hyper-surfaces with time-like normal (i.e. simultaneous detonation in a whole volume) and (ii) to increase this volume to the whole target, by regulating the laser light absorption using nano-shells or nano-rods as antennas. These principles can be realized in an in-line, one dimensional configuration, in the simplest way with two opposing laser beams as in particle colliders. Such, opposing laser beam experiments were also performed recently. Here we study the consequences of the Laser Wake Field Acceleration (LWFA) if we experience it in a colliding laser beam set up. These studies can be applied to laser driven fusion, but also to other rapid phase transition, combustion, or ignition studies in other materials.

physics.plasm-ph↗

arXiv2020

Nanoplasmonic Laser Fusion. Response to Földes and Pokol -- Letter to the Editor

Földes and Pokol in their letter "Inertial fusion without compression does not work either with or without nanoplasmonics" criticized our works \cite{CS2015,CKP2018}. Here we refute their argumentation. Our proposed improvement is the combination of two basic research discoveries: (i) The possibility of detonations on space-time hyper-surfaces with time-like normal (i.e. simultaneous detonation in a whole volume) and (ii) to increase the ignition volume to the whole target, by regulating the laser light absorption using nanoantennas. These principles can be realized in an in-line, one dimensional configuration, in the simplest way with two opposing laser beams as in particle colliders \cite{CsEA2020,Bonasera2019}.

physics.plasm-ph↗