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- 摘要
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A selection of theoretical results in the context of laser-plasma interaction and inertial fusion
摘要： I recall a selection of my results of the last 40 years. I first present a theoretical model of absorption of laser light by a plasma, with an emphasis on its dependence on the laser intensity and wavelength. A second topic concerns the nonlinear and nonlocal electron transport in steep temperature gradients. Thirdly, I present the work on the propagation of a short intense laser pulse in tenuous plasmas. Finally, I discuss the plasma expansion into a vacuum, in particular the structure of the ion front and the prediction of the maximum velocity attained by the ions in the expansion.
关键词： thermal conduction,plasma expansion,collisional absorption,inertial fusion,laser-plasma interaction
更新于2025-09-16 10:30:52
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Modelling the heating process of CFRP by cw-laser radiation with special focus on the heat transfer by thermal radiation between the carbon fibers
摘要： In our talk, we present results of numerical calculations that describe the thermal development within a laser-impacted laminate structure made of carbon layers embedded in a polymer matrix. The FEM-calculations show, that a significant part of the heat transfer is caused by radiative heat transfer between the carbon layers at elevated temperatures. In addition to the FEM calculations, we derive analytical relationships that allow the calculation of equivalent material parameters, especially an equivalent temperature-dependent, anisotropic thermal conduction coefficient. Thus, larger structures in the mm- and cm-range consisting of multiple carbon layers can be described by a simpler geometry of a homogenous material without the need to consider the individual carbon layers having a diameter of a few μm.
关键词： heat conduction,equivalent thermal conduction coefficient,inter fiber thermal radiation,CFRP composite,FEM-calculations
更新于2025-09-12 10:27:22
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Nonlinear absorption dynamics simulated in internal modification of glass at 532nm and 1064nm by ultrashort laser pulses
摘要： Dynamic ionization process at high pulse repetition rate is analysed based on the model consisting of rate equation for free-electrons, Gaussian beam propagation equation, thermal conduction and thermal ionization, showing the plasma generated near the geometrical focus moves toward the laser source periodically by the contribution of avalanche ionization. The effects of laser wavelength on the ionization process are discussed by comparing the contributions of multiphoton ionization and avalanche ionization. The crack tendency of 532nm and 1064nm is also compared between single pulse and multipulse irradiation.
关键词： thermal conduction model,nonlinear ionization process,glass,internal modificatin,thermal ionization,crack,ultrashort laser pulses
更新于2025-09-12 10:27:22
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The effects of curvature on the thermal conduction of bent silicon nanowire
摘要： Curvature induced by mechanical deformation in nanostructures has been found to significantly affect their stability and reliability during applications. In this work, we investigated the effects of curvature induced by mechanical bending on the thermal properties of silicon nanowire (SiNW) by using molecular dynamics simulations. By examining the relationship between the curved geometry and local temperature/heat flux distribution, we found that there is no temperature gradient/heat flux along the radial direction of the bent SiNW, and the local heat current density along the circumferential direction varies with the radius of curvature. Interestingly, a ～10% reduction in the thermal conductivity is found in the bent SiNW due to the depression of long-wavelength phonons caused by its inhomogeneous deformation. The present work demonstrates that the curvature induced by mechanical bending can be used to modulate the thermal conductivity of SiNWs.
关键词： thermal conductivity,curvature,silicon nanowire,thermal conduction,molecular dynamics simulations
更新于2025-09-04 15:30:14