Article
Physics, Fluids & Plasmas
D. X. Liu, T. Tao, J. Li, Q. Jia, J. Zheng
Summary: In this paper, the laser imprint mitigation performance and other physical mechanisms of foam overcoatings are investigated using a two-dimensional radiation hydrodynamic code. It is found that radiation ablation dynamically modulates the density distribution to decrease the amplitude of the perturbation oscillation. Additionally, a longer length of the shocked compression region reduces the amplitude of the perturbed shock front oscillation. Based on these findings, optimal ranges of foam parameters are proposed to mitigate laser imprint.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Fluids & Plasmas
L. Hudec, A. Gintrand, J. Limpouch, R. Liska, S. Shekhanov, V. T. Tikhonchuk, S. Weber
Summary: A sub-grid foam model is developed to simulate the transformation of solid elements in foam into hot plasma under laser energy deposition. The model considers laser energy absorption and scattering, foam element expansion, and solid element ablation. The dynamics of foam elements are described by a set of ordinary differential equations combining self-similar isothermal expansion and stationary ablation model. The incorporation of microscopic single pore model in macroscopic hydrodynamic codes shows good agreement with experimental data.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
M. R. Weis, A. J. Harvey-Thompson, D. E. Ruiz
Summary: Optimizing the performance of the Magnetized Liner Inertial Fusion (MagLIF) platform on the Z pulsed power facility involves coupling a large amount of preheat energy to the fuel, with research focusing on achieving higher yields through increased laser energy.
PHYSICS OF PLASMAS
(2021)
Article
Engineering, Marine
Yuan Lin, Jin Guo, Haonan Li, Zhikun Wang, Ying Chen, Haocai Huang
Summary: In this study, the hydrodynamic performance of a newly developed disk-shaped AUH was investigated through computational fluid dynamics and experimental validation. By modifying the local geometry, the hydrodynamic properties were improved, resulting in reduced drag and increased stability.
Article
Mechanics
F. Hamid, C. Sasmal, R. P. Chhabra
Summary: This study numerically investigates the influence of viscoelastic fluids on flow dynamics past a stationary cylinder in the laminar vortex shedding regime. By utilizing the DMD technique for the first time, it is found that there are significant differences in amplitude and frequency of flow structures between Newtonian and viscoelastic fluids under the same conditions.
Article
Physics, Fluids & Plasmas
Zoe Barbeau, Kumar Raman, Mario Manuel, Sabrina Nagel, Bhimsen Shivamoggi
Summary: A transverse magnetic field can suppress the hydrodynamic instability growth of an unstable plasma interface. This effect has been studied via simulation and now, an experiment is designed to demonstrate this effect in a laboratory setting. The experiment uses lower density target materials to allow faster hydrodynamics and higher plasma conductivity.
PHYSICS OF PLASMAS
(2022)
Article
Chemistry, Physical
Ronen Zangi
Summary: This article explores the correlation between the equilibrium constant for dimerization reactions and the two-body correlations between monomers, showing that the bimolecular rate for dimer formation is proportional to concentration. The study also reveals an inhomogeneous behavior of system's properties when scaling down the system.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
Max Karasik, Jaechul Oh, S. P. Obenschain, A. J. Schmitt, Y. Aglitskiy, C. Stoeckl
Summary: The study shows that pre-expansion of the high-Z coating before use can effectively reduce laser imprint. Results from experiments using a frequency tripled Nd: glass laser system demonstrate reduction in imprint, but require an externally generated low level soft x-ray prepulse. Additionally, the highest imprint reduction is observed with Pd and Au coatings of at least 400 angstrom thickness.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Fluids & Plasmas
Yu-Hsin Chen, Antonio C. Ting, Bahman Hafizi, Michael H. Helle, Luke A. Johnson, Mikhail N. Polyanskiy, Igor V. Pogorelsky, Marcus Babzien, Nicholas P. Dover, Oliver C. Ettlinger, George S. Hicks, Emma-Jane Ditter, Zulfikar Najmudin, Daniel F. Gordon
Summary: We present the results of proton acceleration from hydrogen plasmas irradiated by intense CO2 laser, with the density gradient modified by Nd:YAG laser ablation-driven hydrodynamic shocks. The experimental results agree well with the simulations, but certain laser shots produced unexpectedly high proton energies. This might be attributed to nonlinear propagation effects and focusing of laser pulses through the plasma channel formed by preceding pulses.
PHYSICS OF PLASMAS
(2023)
Article
Computer Science, Information Systems
Miroslav Slouka, Lukas Folta, Ladislav Stanke, Jan Latal, Petr Siska
Summary: This article focuses on the frequency PWM control methodology and experiments on InGaN EELs to study wavelength tuning possibility and near-threshold region behavior. Three main parts discuss different methods of output control, including CW characteristics, PWM control with delayed rising edge of drive current for frequency control, and behavior using PWM with rectangular drive current shape.
Article
Thermodynamics
Jonathan F. MacArt, Jonathan M. Wang, Pavel P. Popov, Jonathan B. Freund
Summary: The ignition of a lean hydrogen-oxygen premixture and subsequent three-dimensional expanding-flame instabilities induced by focused laser breakdown are simulated in detail. Both diffusive-thermal and hydrodynamic instabilities play a role in accelerating flame expansion, with the global Karlovitz number serving as a measure of instability development. The study emphasizes the importance of vorticity production in destabilizing the flame propagation process.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Astronomy & Astrophysics
Andrea K. Dupree, Klaus G. Strassmeier, Thomas Calderwood, Thomas Granzer, Michael Weber, Kateryna Kravchenko, Lynn D. Matthews, Miguel Montarges, James Tappin, William T. Thompson
Summary: The bright supergiant Betelgeuse underwent a historic optical dimming event in 2020. Observations reveal a substantial mass ejection and resulting changes in temperature and density of the star. The ejected mass could represent a significant fraction of the star's total annual mass-loss rate.
ASTROPHYSICAL JOURNAL
(2022)
Article
Engineering, Electrical & Electronic
Eunwook Jeong, Sang-Geul Lee, Jong-Seong Bae, Seung Min Yu, ChaeWon Mun, Seung Zeon Han, Gun-Hwan Lee, Eun-Ae Choi, Jungheum Yun
Summary: Oxidation of silver film electrodes can lead to catastrophic degradation of their electrical and optical properties. This study presents computational and experimental evidence for substoichiometric silver oxidation, which has unique physicochemical properties that differ from stoichiometric and higher oxidation states. Substoichiometric oxidation can improve the morphology and structure of silver film electrodes, preventing oxidation-induced optoelectrical degradation. These findings go beyond traditional conclusions and have significant implications for the preparation of highly efficient silver electrodes.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Review
Chemistry, Analytical
Dongmei Huang, Yihuan Shi, Feng Li, P. K. A. Wai
Summary: This review discusses the theoretical models and experimental techniques of Fourier domain mode-locked (FDML) lasers, and explores their applications in various fields.
Article
Physics, Applied
Alexey N. Volkov
Summary: The splitting of laser-induced plumes into fast and slow components is commonly attributed to ion acceleration by the ambipolar electric field, while the snow-plow effect explains the presence of the fast component even in neutral plumes. Kinetic simulations also predict bimodal distributions of plasma emission intensity, with a slow peak caused by radiation absorption during the laser pulse and a fast peak appearing after the pulse at the plume edge. The fast component, characterized by a higher degree of ionization, is only observed in a limited range of ambient pressure and for a limited time period.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Applied
T. Wiste, O. Maliuk, V. Tikhonchuk, T. Lastovicka, J. Homola, K. Chadt, S. Weber
Summary: This paper presents an approach to design and fabricate additive manufactured (AM) foams for laser-plasma interaction experiments. It includes the selection of cellular structure, optimization of mechanical properties using finite element approach, and foam printing on dielectric and conducting substrates.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Yiming Pan, Kentaro Tomita, Yukihiko Yamagata, Atsushi Sunahara, Katsunobu Nishihara
Summary: This study reports the evolution history of laser produced plasma (LPP) expansion dynamics, providing experimental evidence for theoretical models. The results suggest that during the laser pulse, the LPP expands approximately isothermally and predominantly in a one-dimensional manner in the target normal direction.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
T. Ozaki, Y. Abe, Y. Arikawa, Y. Sentoku, J. Kawanaka, S. Tokita, N. Miyanaga, T. Jitsuno, Y. Nakata, K. Tsubakimoto, A. Sunahara, T. Jhozaki, E. Miura, O. Komeda, A. Iwamoto, H. Sakagami, S. Okihara, K. Ishii, R. Hanayama, Y. Mori, Y. Kitagawa
Summary: Polystyrene deuteride shell targets with two holes were imploded and heated by the Gekko XII laser and LFEX laser respectively in a direct fast ignition experiment. Injecting an ultra-intense laser into the blow-off plasma created by the imploding laser resulted in the generation of electrons far from the target core, with increased energy. The use of shell targets with holes can reduce the inflow of implosion plasma onto the LFEX path, leading to lower effective electron temperature and higher coupling efficiency. The contribution of ions to target heating in direct fast ignition is significant, accounting for 74% of the total heating energy.
Article
Optics
Qi Lu, Xiang Zhang, Santiago Lopez, Haicheng Mei, Liang Xu, Qingqing Liang, Aurelien Houard, Vladimir Tikhonchuk, Andre Mysyrowicz, Eduardo Oliva, Yi Liu
Summary: We report a spectral splitting effect in the cavity-less lasing emission of nitrogen ions at 391.4 nm when pumped by 800-nm femtosecond laser pulses. The R and P branches both experience spectral splitting with increased nitrogen gas pressure and pump pulse energy. Similar split spectral line is observed for the amplified emission with external injected seeding pulse, but no such phenomenon is observed for fluorescence radiation with more abundant R branch structures. Our theoretical model considers gas ionization, excitation competition, and amplification in the plasma to explain this spectral splitting effect.
Article
Physics, Fluids & Plasmas
S. Shekhanov, A. Gintrand, L. Hudec, R. Liska, J. Limpouch, S. Weber, V. Tikhonchuk
Summary: This study investigates the interaction between lasers and foam targets, which is important for inertial confinement fusion studies and the creation of secondary sources of energetic particles and radiation. By applying the Mie theory, the analysis shows enhanced laser absorption due to plasma resonance when lasers interact with thin wires, and this conclusion is confirmed by detailed kinetic simulations. Numerical simulations also determine the characteristic time for the transformation of solid elements into plasma and the energy partition between electrons and ions.
PHYSICS OF PLASMAS
(2023)
Article
Multidisciplinary Sciences
Kentaro Tomita, Yiming Pan, Atsushi Sunahara, Kouichiro Kouge, Hakaru Mizoguchi, Katsunobu Nishihara
Summary: This study reports the first measurement of two-dimensional flow-velocity fields in Sn-LPPs using the collective Thomson scattering technique. The results show that the plasma inflows maintain the temperature and density suitable for EUV light emission, leading to increased EUV output.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Applied
R. Danylo, X. Zhang, A. Lisova, A. Houard, Y. Liu, V. Tikhonchuk, A. Mysyrowicz
Summary: In this study, the lasing characteristics of N(2)(+) under 428nm pumping are investigated by varying the time delay between two 800nm ultrashort pumping pulses. It is observed that the laser emission is significantly reduced when the time delay is in the range of -20ps < dt < +20ps. From the analysis of the quenching results, it is concluded that the mechanism of lasing corresponds to a coherent two-photon amplification scheme, rather than the common population-inverted one-photon amplification mechanism.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Condensed Matter
Susumu Kato, Shota Ono, Atsushi Sunahara, Yuji Sato, Masahiro Tsukamoto
Summary: The optical properties of pure liquid copper were investigated using density functional theory with the Quantum ESPRESSO package. The effects of structural changes were examined by comparing the electron density of states and imaginary part of the dielectric function between the crystalline and liquid states with densities near the melting point. The results indicated that the effect of interband transitions remains in the structural changes near the melting point.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Computer Science, Interdisciplinary Applications
A. Chrisment, A. Debayle, J. -L. Feugeas, P. Loiseau, P. -E. Masson-Laborde, J. Mathiaud, Ph. Nicolai, V. Tikhonchuk
Summary: In inertial confinement fusion plasma, the electron population may be strongly out-of-equilibrium, making it difficult to analyze the effects of microscopic processes on the macroscopic evolution. To overcome this, reduced kinetic transport models are developed to provide a kinetic closure and analyze finer kinetic phenomena.
MATHEMATICS AND COMPUTERS IN SIMULATION
(2023)
Article
Physics, Fluids & Plasmas
L. Hudec, A. Gintrand, J. Limpouch, R. Liska, S. Shekhanov, V. T. Tikhonchuk, S. Weber
Summary: A sub-grid foam model is developed to simulate the transformation of solid elements in foam into hot plasma under laser energy deposition. The model considers laser energy absorption and scattering, foam element expansion, and solid element ablation. The dynamics of foam elements are described by a set of ordinary differential equations combining self-similar isothermal expansion and stationary ablation model. The incorporation of microscopic single pore model in macroscopic hydrodynamic codes shows good agreement with experimental data.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Applied
S. Ter-Avetisyan, M. Schnuerer, V. Tikhonchuk
Summary: This paper reports the observation of negative ions in experiments using high-power lasers to generate energetic positively charged ions. By interacting a high intensity laser pulse with a water spray, a large number of negative ions and neutral atoms with MeV energies were obtained. The mechanism of negative ion formation and acceleration is still under discussion.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Yiming Pan, Atsushi Sunahara, Shinichi Namba, Takeshi Higashiguchi, Kentaro Tomita
Summary: This study demonstrates the laser intensity scaling of electron temperature in Gd laser-produced plasmas through experiment and simulation. The measured maximum electron temperature in Gd plasmas increase with increasing laser intensity, and the relationship follows T-e proportional to I-L(0.37). The simulation results show good agreement with the experimental data and indicate a modified dependence of T-e proportional to I-L(0.44) at higher laser intensities.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Hsin-Hui Huang, Saulius Juodkazis, Eugene G. Gamaly, Vladimir T. Tikhonchuk, Koji Hatanaka
Summary: This study analyzes the processes produced by the interaction of two subsequent ultra-short laser pulses with a water flow, and finds that this interaction generates strong THz pulses and enhanced X-ray emission. It is demonstrated that these emissions are produced by the interaction of a main laser pulse with liquid water ejected from the surface by a pre-pulse, resulting in the acceleration of energetic electron beams. This scheme enables efficient energy conversion in THz pulses.
Article
Physics, Multidisciplinary
K. Kawasaki, G. Cristoforetti, T. Idesaka, Y. Hironaka, D. Tanaka, D. Batani, S. Fujioka, L. A. Gizzi, M. Hata, T. Johzaki, K. Katagiri, R. Kodama, H. Nagatomo, S. Matsuo, Ph. Nicolai, N. Ozaki, Y. Sentoku, R. Takizawa, A. Yogo, H. Yamada, K. Shigemori
Summary: In direct-drive inertial confinement fusion, the addition of hydrogen to the ablator increases the laser plasma instabilities, such as stimulated Raman scattering and two-plasmon decay. The enhancement is mainly attributed to the high ion acoustic wave damping driven by the hydrogen ions, suggesting that Langmuir decay instability causes stimulated Raman scattering saturation, whereas other mechanisms (such as cavitation) could overwhelm the two-plasmon decay saturation.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Physics, Multidisciplinary
S. Marini, M. Grech, P. S. Kleij, M. Raynaud, C. Riconda
Summary: A mechanism of electron acceleration has been discovered where a relativistically intense laser irradiates the wedge of an overdense plasma. This mechanism generates a diffracted electromagnetic wave with a significant longitudinal electric field, which accelerates electrons over long distances to relativistic energies. High-density electron bunches with energies up to several hundred MeV are obtained using a laser beam of Ilambda(2)(0) = 3.5 x 10(19) W mu m(2)/cm(2).
PHYSICAL REVIEW RESEARCH
(2023)