Angular momentum oscillation in spiral-shaped foil plasmas

Abstract

Two types of spiral-shaped foils are investigated for generating significant angular momentum (AM) in plasmas by reflecting a relativistic Gaussian pulse into a vortex laser beam with the same topological charge. This is the first time to find that AM oscillation exists in specific spiral-shaped foils during laser-plasma interaction, while AM oscillation is not observed in other types of foils. Both threedimensional particle-in-cell simulations and theoretical results have confirmed this finding. AM oscillation is demonstrated to be induced by the asymmetric field on the foil surface, and this asymmetric field can be modulated in order to strengthen or weaken the oscillation amplitude by redesigning the foil surface. AM oscillation is expected to bring insight into radiation, particle heating and other mechanisms with AM effects.

Efficient bright γ-ray vortex emission from a laser-illuminated light-fan-in-channel target

“…With an additional degree of freedom, vortex photons can also carry more information concerning the physical circumstances of their sources, e.g., the magnetic field and radiation field [27] . A vortex laser pulse, e.g., Laguerre-Gaussian (LG) laser, has a helical phase front, hollow transverse field distribution, and strong longitudinal electric field [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] , enabling the generation of energetic charged particles with orbital angular momentum (OAM) [33][34][35][36][37][38][39][40][41][42]48] , high OAM X/γ-ray [43,49] emission and harmonics generation [44,45,50] . To the best of our knowledge, the highest intensity of LG laser pulse achieved experimentally is around 10 20 W/cm 2 with total power of tens of terawatts (TW) [32,51] .…”

Direct Acceleration of an Annular Attosecond Electron Slice Driven by Near-Infrared Laguerre–Gaussian Laser

“…Previously, optical tweezers or optical wrenches driven by LG lasers have been applied to concentrate and rotate micrometer matter in the nonrelativistic regime [34,35]. With the development of advanced laser facilities [2,36], an LG laser has the potential to be extended to the relativistic regime [37][38][39][40][41]. Now the highest intensity of the LG laser can reach up to 6.3× 10 19 W/cm 2 by using the reflected phase plate on the petawatt laser facility in experiments [26].…”

Transport coefficients of the fully ionized plasma with kappa-distribution and in strong magnetic field

“…In the field of space plasmas, many works about the measurements of plasma velocity distribution indicate that kappa-distributions are more suitable to model the plasma than Maxwellian velocity distributions especially at high energies in various space plasmas, for example, star's corona, 1 the solar wind, 2-4 the planetary exosphere, [5][6][7] the planetary magnetosphere, [8][9][10] and also some other observations, 11,12 etc. Therefore the kappa-distribution, as one of non-Maxwellian distributions, has already been a very interesting research topic in the related studies of astrophysical and space plasmas, such as origin of the kappa-distribution, [13][14][15] physical explanations of the kappa-parameter, 16,17 connections between the kappa-distribution and the nonextensive statistics, 18,19 ion-acoustic waves and dust-acoustic waves in plasmas, [20][21][22][23][24][25][26] and also some other plasma applications, [27][28][29][30] etc.…”