arXiv subjects

Anle Lei

Publications and source records attributed to Anle Lei.

4 recordsLinked to original sources

arXiv2026

Efficient hot electron generation via low-coherence lasers

Hot electrons generated in laser-produced plasmas are a central focus in inertial confinement fusion, laboratory astrophysics, and high-energy-density physics. These electrons originate from instabilities in nonlinear laser-plasma interactions, which are critically modulated by laser bandwidth. Here, we experimentally demonstrate enhanced generation of hot electrons by utilizing instantaneous low-coherence lasers with two bandwidths (0.2% and 0.6%) at intensities of 2-8x10^{14} W/cm^2 and energies up to 620 J. A significant enhancement of hot electron temperature and hard X-ray yield is observed with the broadband lasers compared to a conventional narrowband laser. The results show that the hot electron energy conversion efficiency of the 0.6% broadband laser is approximately 4 times higher than that of the narrowband laser, reaching a maximum value of 2.8%. These findings validate a moderate-bandwidth laser as an efficient hot electron source and support the generation of bright X-ray sources for advanced imaging in high-energy-density physics.

physics.plasm-ph↗

arXiv2025

Effects of laser-plasma parameters on sub-nanosecond evolution of cross-beam energy transfer

Cross-beam energy transfer (CBET) between two lasers is investigated through theoretical analysis and two-dimensional hybrid simulations over sub-nanosecond to nanosecond timescales and millimeter spatial scales. A finite frequency-difference range for CBET development is derived. Ion acoustic wave (IAW) damping is found to broaden this range while reducing the growth rate of stimulated Brillouin scattering (SBS). CBET exhibits distinct nonlinear behaviors across different laser-intensity regimes. Denoting $I_{14}=1\times 10^{14} \mathrm{W/cm^2}$ for a laser wavelength of $351 \mathrm{nm}$, at moderate intensities ($1<I/I_{14}<8$), CBET grows weakly and saturates at a low level due to pump depletion. In the strongly coupled SBS regime ($I/I_{14} \gtrsim 8$), harmonic IAW and nonlinear wave-particle interactions emerge. The generation of harmonic IAW reduces the normal IAW mode, while ion-trapping-induced spectral broadening of normal IAW mode causes frequency mismatch, leading to nonlinear reduction of CBET. After the saturation of harmonic mode, ion trapping broadens harmonic IAW spectrum and weakens it, triggering a secondary growth stage of CBET. After approximately $60 \mathrm{ps}$, CBET approaches quasi-steady-state. The maximum total energy transfer occurs at a frequency difference below the linear matching condition due to the trapping-induced IAW redshift. Based on these two intensity regimes, piecewise scalings of the quasi-saturated total energy transfer rate with $I/I_{14}$ are obtained and shown to be robust against spot size. Speckle effects reduce high-intensity overlap and thus the energy transfer rate. The effects of plasma temperature, density, and flow velocity on CBET are also examined.

physics.plasm-ph↗

arXiv2020

Bremsstrahlung emission and plasma characterization driven by moderately relativistic laser-plasma interactions

Relativistic electrons generated by the interaction of petawatt-class short laser pulses with solid targets can be used to generate bright X-rays via bremsstrahlung. The efficiency of laser energy transfer into these electrons depends on multiple parameters including the focused intensity and pre-plasma level. This paper reports experimental results from the interaction of a high intensity petawatt-class glass laser pulses with solid targets at a maximum intensity of $10^{19}$ W/cm$^2$. In-situ measurements of specularly reflected light are used to provide an upper bound of laser absorption and to characterize focused laser intensity, the pre-plasma level and the generation mechanism of second harmonic light. The measured spectrum of electrons and bremsstrahlung radiation provide information about the efficiency of laser energy transfer.

physics.plasm-ph↗

arXiv2013

Ion heating dynamics in solid buried layer targets irradiated by ultra-short intense laser pulses

We investigate bulk ion heating in solid buried layer targets irradiated by ultra-short laser pulses of relativistic intensities using particle-in-cell simulations. Our study focuses on a CD2-Al-CD2 sandwich target geometry. We find enhanced deuteron ion heating in a layer compressed by the expanding aluminium layer. A pressure gradient created at the Al-CD2 interface pushes this layer of deuteron ions towards the outer regions of the target. During its passage through the target, deuteron ions are constantly injected into this layer. Our simulations suggest that the directed collective outward motion of the layer is converted into thermal motion inside the layer, leading to deuteron temperatures higher than those found in the rest of the target. This enhanced heating can already be observed at laser pulse durations as low as 100 femtoseconds. Thus, detailed experimental surveys at repetition rates of several ten laser shots per minute are in reach at current high-power laser systems, which would allow for probing and optimizing the heating dynamics.

physics.plasm-ph↗