- 标题
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Fast collisional electron heating and relaxation in thin foils driven by a circularly polarized ultraintense short-pulse laser
摘要： The creation of well-thermalized, hot and dense plasmas is attractive for warm dense matter studies. We investigate collisionally induced energy absorption of an ultraintense and ultrashort laser pulse in a solid copper target using particle-in-cell simulations. We ?nd that, upon irradiation by a 2 × 1020 W cm?2 intensity, 60 fs duration, circularly polarized laser pulse, the electrons in the collisional simulation rapidly reach a well-thermalized distribution with ～3.5 keV temperature, while in the collisionless simulation the absorption is several orders of magnitude weaker. Circular polarization inhibits the generation of suprathermal electrons, while ensuring ef?cient bulk heating through inverse bremsstrahlung, a mechanism usually overlooked at taking account of both collisional and ?eld ionization, yields similar results: the bulk electrons are heated to ～2.5 keV, but with a somewhat lower degree of thermalization than in the pre-set, ?xed-ionization case. The collisional absorption mechanism is found to be robust against variations in the laser parameters. At ?xed laser pulse energy, increasing the pulse duration rather than the intensity leads to a higher electron temperature.
关键词： plasma dynamics,plasma heating,plasma simulation
更新于2025-09-23 15:21:01
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Collinear dual-pulse laser optical breakdown and energy deposition
摘要： A non-equilibrium model for laser-generated plasmas is used to represent collinear dual nano-second-pulse interactions. In the specific case considered, the breakdown is initiated with an ultraviolet (UV) laser pulse at 266 nm, which pre-ionizes the gas, and it is followed by a near-infrared (NIR) pulse at 1064 nm, which deposits significant energy into the ionized mixture. The model is validated against corresponding experiments, and simulation results are interrogated to understand key features of the plasma-kernel dynamics in the breakdown phase, and the initial post-breakdown vorticity and plasma-core decay.
关键词： energy deposition,laser-induced breakdown,non-equilibrium plasma,plasma dynamics,dual-pulse laser
更新于2025-09-23 15:19:57
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Laser-Produced Magnetic-Rayleigh-Taylor Unstable Plasma Slabs in a 20?T Magnetic Field
摘要： Magnetized laser-produced plasmas are central to many novel laboratory astrophysics and inertial confinement fusion studies, as well as in industrial applications. Here we provide the first complete description of the three-dimensional dynamics of a laser-driven plasma plume expanding in a 20 T transverse magnetic field. The plasma is collimated by the magnetic field into a slender, rapidly elongating slab, whose plasma-vacuum interface is unstable to the growth of the 'classical,' fluidlike magnetized Rayleigh-Taylor instability.
关键词： plasma dynamics,magnetic field,Rayleigh-Taylor instability,laser-produced plasmas
更新于2025-09-16 10:30:52
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Spatial Molecular AlO Temperature Distributions in Laser-Induced Plasma
摘要： Spatially resolved, line-of-sight measurements of aluminum monoxide emission spectra in laser ablation plasma are used with Abel inversion techniques to extract radial plasma temperatures. Contour mapping of the radially deconvolved signal intensity shows a ring of AlO formation near the plasma boundary with the ambient atmosphere. Simulations of the molecular spectra were coupled with the line profile fitting routines. Temperature results are presented with simultaneous inferences from lateral, asymmetric radial, and symmetric radial AlO spectral intensity profiles. This analysis indicates that shockwave phenomena in the radial profiles, including a temperature drop behind the blast wave created during plasma initiation were measured.
关键词： laser-induced plasma,Abel transform,plasma spectroscopy,molecular spectroscopy,plasma dynamics,laser-induced breakdown spectroscopy,diatomic spectroscopy
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Filamentation-Based Transient Dynamic Studies via Third-Harmonic Generation in Gases
摘要： We present a novel pump-probe approach to investigate few-femtosecond transient dynamics in gases. Furthermore we demonstrate its feasibility by showing new observations about transient plasma dynamics in molecular and atomic gases. The understanding of laser-driven plasma dynamics is important to a wide field of topics such as wakefield acceleration [1] or laser-induced breakdown spectroscopy [2]. Our approach is based on an earlier experiment that investigated plasma-enhanced third-harmonic generation by two interacting filaments [3]. In contrast, we are recording the full third-harmonic spectrum for every delay step, temporarily resolved with a step size down to 0.7 fs. Hence, we are able to study ultrafast plasma-related dynamics in the temporal and spectral domain with unprecedented resolution.
关键词： plasma dynamics,gases,transient dynamics,pump-probe,third-harmonic generation
更新于2025-09-12 10:27:22