Simulations of spin/polarization-resolved laser-plasma interactions in the nonlinear QED regime

Strong-field quantum electrodynamics(SF-QED)plays a crucial role in ultraintense laser-matter interactions and demands sophisticated techniques to understand the related physics with new degrees of freedom,including spin angular momentum.To investigate the impact of SF-QED processes,we have introduced spin/polarization-resolved nonlinear Compton scattering,nonlinear Breit-Wheeler,and vacuum birefringence processes into our particle-in-cell(PIC)code.In this article,we provide details of the implementation of these SF-QED modules and share known results that demonstrate exact agreement with existing single-particle codes.By coupling normal PIC simulations with spin/polarization-resolved SF-QED processes,we create a new theoretical platform to study strong-field physics in currently running or planned petawatt or multi-petawatt laser facilities.

X-ray emission for Ar^(11+)ions impacting on various targets in the collisions near the Bohr velocity

X-ray emission from the collisions of 3 MeV Ar^(11+)ions with V,Fe,Co,Ni,Cu,and Zn is investigated.Both the x-rays of the target atom and projectile are observed simultaneously.The x-ray yield is extracted from the original count.The inner-shell ionization cross section is estimated by the binary encounter approximation model and compared with the experimental result.The remarkable result is that the Ar K-shell x-ray yield is diminished with the target atomic number increasing,which is completely opposite to the theoretical calculation.That is interpreted by the competitive consumption of the energy loss for the ionization of inner-shell electrons between the projectile and target atom.

Generation of highly-polarized high-energy brilliant γ-rays via laser-plasma interaction

The generation of highly polarized high-energy brilliantγ-rays via laser–plasma interaction is investigated in the quantum radiation-reaction regime.We employ a quantum electrodynamics particle-in-cell code to describe spin-resolved electron dynamics semiclassically and photon emission and polarization quantum mechanically in the local constant field approximation.As an ultrastrong linearly polarized(LP)laser pulse irradiates a near-critical-density(NCD)plasma followed by an ultrathin planar aluminum target,the electrons in the NCD plasma are first accelerated by the driving laser to ultrarelativistic energies and then collide head-on with the laser pulse reflected by the aluminum target,emitting brilliant LPγ-rays via nonlinear Compton scattering with an average polarization of about 70%and energy up to hundreds of MeV.Suchγ-rays can be produced with currently achievable laser facilities and will find various applications in high-energy physics and laboratory astrophysics.

Nd L-shell x-ray emission induced by light ions

The L-shell x-ray of Nd has been obtained for 300-600 keV He2+ions impacting,and compared with that produced by H+and H2+ions.The threshold of projectile kinetic energy for L-shell ionization of Nd is crudely verified in the energy region of about 300-400 keV.It is found that the energy of the distinct L-subshell x-rays has a blue shift.The relative intensity ratios of Lβ_(1,3,4)and Lβ_(2,15)to Lα_(1,2)x-ray are enlarged compared to the atomic data,and they decrease with the increase of the incident energy,and increase with increasing the effective nuclear charge of the incident ions.That is interpreted by the multiple ionization of outer-shells induced by light ions.

A fitting formula for electron–ion energy partition fraction of 3.54-MeV fusion alpha particles in hot dense deuterium–tritium plasmas

Based on our previous work(Phys.Plasmas 25 012704(2018)),a fitting formula is given for electron-ion energy partition fraction of 3.54-MeV fusion alpha particles in deuterium-tritium(DT) plasmas as a function of plasma mass density ρ,electron temperature T_(e),and ion temperature T_(i).The formula can be used in a huge range of the plasma state,where ρ varies between 1.0 g/cc~10.0^(3) g/cc and both T_(e) and T_(i) change from 0.1 keV to 100.0 keV.Relativistic effect for electrons is investigated including the effect of the projectile recoil in the plasmas at T_(e)≥ 50.0 keV.The partition fraction for T_(e)>T_(i) is found to be close to that for T_(e)=T_(i). The comparisons with other fitting results are made at some plasma densities when T_(e)=T_(i),and the difference is explained.The fitting result is very close to the calculated one in most cases,which is convenient for the simulation of alpha heating in hot dense DT plasmas for inertial confined fusion.

Microstructure and properties of Inconel 625+WC composite coatings prepared by laser cladding

Inconel 625+WC composite coatings were prepared on the surface of 2Cr13 steel by laser cladding.The microstructure,microhardness and corrosion resistance of the composite coatings with different WC contents were investigated in detail.The results show that the phase compositions of the composite coatings are mainly y-(Ni,Fe)and various carbides.The content of WC has a significant effect on the microstructure of the cladding layers.When the WC content is 10 wt%and 15 wt%,the cladding layer has developed columnar dendrites.However,the 20 wt%WC coating is mainly composed of cellular dendrites and columnar dendrites.With the increase in WC content,the average hardness of the composite coating gradually increases.The average hardness of 20 wt%WC coating is the highest(HV_(1)536.98),which is a factor of2.64 greater than that of the 2 Cr13 steel matrix.Electrochemical results show that all the composite coatings have better corrosion resistance than 2 Cr13 steel in 0.5 mol·L^(-1) HCl solution.The composite coating with 10 wt%WC has the best corrosion resistance,its corrosion potential(E_(corr))is 0.78806 V higher than that of 2 Cr13 steel,and the corrosion current density(I_(corr))is only 0.86%that of 2 Cr13 steel.