scholarly journals Generation and collective interaction of giant magnetic dipoles in laser cluster plasma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Andreev ◽  
K. Platonov ◽  
Zs. Lécz ◽  
N. Hafz

AbstractInteraction of circularly polarized laser pulses with spherical nano-droplets generates nanometer-size magnets with lifetime on the order of hundreds of femtoseconds. Such magnetic dipoles are close enough in a cluster target and magnetic interaction takes place. We investigate such system of several magnetic dipoles and describe their rotation in the framework of Lagrangian formalism. The semi-analytical results are compared to particle-in-cell simulations, which confirm the theoretically obtained terrahertz frequency of the dipole oscillation.

2009 ◽  
Vol 27 (1) ◽  
pp. 3-7 ◽  
Author(s):  
W.-M. Wang ◽  
Z.-M. Sheng ◽  
J. Zhang

AbstractElectron injection into a laser wakefield by the colliding of two circularly polarized laser pulses is analyzed by the Hamiltonian approach and particle-in-cell simulations. If the pump pulse driving the laser wakefield is right-circularly-polarized, electron injection is found only when the counter-propagating injection pulse is left-circularly-polarized and vice versa. This holds when the injection pulse is at low intensity and has a frequency near the pump pulse frequency ω0. For a moderately intense injection pulse, even if the two pulses have the same polarization, electron injection is found but with less efficiency. It is also found that the injection pulse with the frequency within [0.5ω0,3ω0] can still create electron injection efficiently provided it has the opposite polarization with the pump pulse.


2009 ◽  
Vol 27 (4) ◽  
pp. 611-617 ◽  
Author(s):  
T.P. Yu ◽  
M. Chen ◽  
A. Pukhov

AbstractWe study proton acceleration from a foil target with a transversely varying density using multi-dimensional Particle-in-Cell (PIC) simulations. In order to reduce electron heating and deformation of the target, circularly polarized Gaussian laser pulses at intensities on the order of 1022 Wcm−2 are used. It is shown that when the target density distribution fits that of the laser intensity profile, protons accelerated from the center part of the target have quasi-monoenergetic spectra and are well collimated. In our two-dimensional PIC simulations, the final peak energy can be up to 1.4 GeV with the full-width of half maximum divergence cone of less than 4°. We observe highly efficient energy conversion from the laser to the protons in the simulations.


2015 ◽  
Vol 34 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Z. Lécz ◽  
A. Andreev ◽  
A. Seryi

AbstractThe efficient transfer of angular orbital momentum from circularly polarized laser pulses into ions of solid density targets is investigated with different geometries using particle-in-cell simulations. The detailed electron and ion dynamics presented focus upon the energy and momentum conversion efficiency. It is found that the momentum transfer is more efficient for spiral targets and the maximum value is obtained when the spiral step is equal to twice the laser wavelength. This study reveals that the angular momentum distribution of ions strongly depends up on the initial target shape and density.


2007 ◽  
Vol 21 (03n04) ◽  
pp. 579-589 ◽  
Author(s):  
ANDREA MACCHI ◽  
FULVIO CORNOLTI

The acceleration of ions in the interaction of ultrashort, high intensity, circularly polarized laser pulses with overdense plasmas has been theoretically investigated. By using particle-in-cell (PIC) simulations it is found that high-density, short duration ion bunches moving into the plasma are promptly generated at the laser-plasma interaction surface. This regime is qualitatively different from ion acceleration regimes driven by fast electrons such as sheath acceleration at the rear side of the target. A simple analytical model accounts for the numerical observations and provides scaling laws for the ion bunch velocity and generation time as a function of pulse intensity and plasma density. The ion bunches have moderate energies (100 keV-1 MeV) but very high density and low beam divergence, and might be of interest for problems of ultrafast compression, acceleration or heating of high–density matter. In particular, we have studied their application to the development of compact sources of fusion neutrons. We analyzed two target schemes showing that intense neutron bursts with femtosecond duration are produced.


2007 ◽  
Vol 21 (03n04) ◽  
pp. 642-646 ◽  
Author(s):  
A. ABUDUREXITI ◽  
Y. MIKADO ◽  
T. OKADA

Particle-in-Cell (PIC) simulations of fast particles produced by a short laser pulse with duration of 40 fs and an intensity of 1020W/cm2 interacting with a foil target are performed. The experimental process is numerically simulated by considering a triangular concave target illuminated by an ultraintense laser. We have demonstrated increased acceleration and higher proton energies for triangular concave targets. We also determined the optimum target plasma conditions for maximum proton acceleration. The results indicated that a change in the plasma target shape directly affects the degree of contraction accelerated proton bunch.


2021 ◽  
Author(s):  
Dong-Ning Yue ◽  
Min Chen ◽  
Yao Zhao ◽  
Pan-Fei Geng ◽  
Xiao-Hui Yuan ◽  
...  

Abstract Generation of nonlinear structures, such as stimulated Raman side scattering waves, post-solitons and electron vortices, during ultra-short intense laser pulse transportation in near-critical-density (NCD) plasmas are studied by using multi-dimensional particle-in-cell (PIC) simulations. In two-dimensional geometries, both P- and S- polarized laser pulses are used to drive these nonlinear structures and to check the polarization effects on them. In the S-polarized case, the scattered waves can be captured by surrounding plasmas leading to the generation of post-solitons, while the main pulse excites convective electric currents leading to the formation of electron vortices through Kelvin-Helmholtz instability (KHI). In the P-polarized case, the scattered waves dissipate their energy by heating surrounding plasmas. Electron vortices are excited due to the hosing instability of the drive laser. These polarization dependent physical processes are reproduced in two different planes perpendicular to the laser propagation direction in three-dimensional simulation with linearly polarized laser driver. The current work provides inspiration for future experiments of laser-NCD plasma interactions.


2017 ◽  
Vol 95 (24) ◽  
Author(s):  
Michela F. Picardi ◽  
Alejandro Manjavacas ◽  
Anatoly V. Zayats ◽  
Francisco J. Rodríguez-Fortuño

2020 ◽  
Author(s):  
Hsin-Hui Huang ◽  
Saulius Juodkazis ◽  
Eugene Gamaly ◽  
Takeshi Nagashima ◽  
Tetsu Yonezawa ◽  
...  

Abstract Intense THz wave sources are highly expected for further progresses in nonlinear THz science and practical implementation of non-ionizing radiation in sensing and communications. Solid-based sources have inherent limits of material breakdown, while intense laser irradiation of liquids is a promising emerging technique for THz wave and hard X-ray emission. Water-based THz emission shows intensity enhancements up to 103 times when laser-pulse pairs with nanosecond delay are used. Here we show circularly- polarized THz wave emission from thin water flow irradiated by two time-separated and linearly-polarized femtosecond laser pulses. THz time-domain spectroscopy reveals the circularly-polarized THz emission dominates 4.7 ns after the first pulse irradiation. THz wave detection delay in the spectroscopy and time-resolved micrography indicate that the THz wave emission originates from the rarefied volume in front of the flow. Radial relaxation of charges (currents) in the focal volume where ponderomotive charge depletion occurred is the origin for the circular polarization; tight focusing localized THz wave emission to the sub-wavelength region.


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