As an intense picosecond laser pulse irradiates a hydrocarbon target,the protons therein can be accelerated by the radiation pressure as well as the sheath field behind the target.We investigate the effect of the lase...As an intense picosecond laser pulse irradiates a hydrocarbon target,the protons therein can be accelerated by the radiation pressure as well as the sheath field behind the target.We investigate the effect of the laser and hydrocarbon target parameters on proton acceleration with two/threedimensional particle-in-cell simulations.It is found that the resulting two-ion species plasma can generate a multiple peaked charge-separation field that accelerates the protons.In particular,a smaller carbon-to-hydrogen ratio,as well as the thinner and/or lower density of the target,leads to a larger sheath field and thus proton beams with a larger cutoff energy and smoother energy spectrum.These results may be useful in achieving high-flux quasi-monoenergetic proton beams by properly designing the hydrocarbon target.展开更多
Ultrashort pulsed laser-induced periodic surface structures(LIPSS)can be generated on difFerent kinds of materials,which are widely utilized for modifying surface properties such as wettability,adhesion,and tribologic...Ultrashort pulsed laser-induced periodic surface structures(LIPSS)can be generated on difFerent kinds of materials,which are widely utilized for modifying surface properties such as wettability,adhesion,and tribological,as well as optical performances.Previous studies have focused mainly on one-dimensional LIPSS(i.e.,line structure)generation.In this study,a picosecond pulsed laser was used to irradiate stainless-steel surfaces for generating two-dimensional LIPSS,namely nanodot structures,by cross-scanning the laser beam for a different number of times.The obtained nanodot structures were found to be super hydrophilic just after laser irradiation,but turned to be hydrophobic after exposure in air for a few days.By cross・scanning the laser beam for the same number of times,local LIPSS rewriting was realized.This study showed the possibility of improving the homogeneity of the surface properties of steel materials through laser-induced nanodot structuring.展开更多
基金the National Key R&D Program of China(No.2016YFA0401100)National Natural Science Foundation of China(Nos.12175154,11875092,and 12005149)+1 种基金the Natural Science Foundation of Top Talent of SZTU(Nos.2019010801001 and 2019020801001)The EPOCH code is used under UK EPSRC contract(EP/G055165/1 and EP/G056803/1).
文摘As an intense picosecond laser pulse irradiates a hydrocarbon target,the protons therein can be accelerated by the radiation pressure as well as the sheath field behind the target.We investigate the effect of the laser and hydrocarbon target parameters on proton acceleration with two/threedimensional particle-in-cell simulations.It is found that the resulting two-ion species plasma can generate a multiple peaked charge-separation field that accelerates the protons.In particular,a smaller carbon-to-hydrogen ratio,as well as the thinner and/or lower density of the target,leads to a larger sheath field and thus proton beams with a larger cutoff energy and smoother energy spectrum.These results may be useful in achieving high-flux quasi-monoenergetic proton beams by properly designing the hydrocarbon target.
文摘Ultrashort pulsed laser-induced periodic surface structures(LIPSS)can be generated on difFerent kinds of materials,which are widely utilized for modifying surface properties such as wettability,adhesion,and tribological,as well as optical performances.Previous studies have focused mainly on one-dimensional LIPSS(i.e.,line structure)generation.In this study,a picosecond pulsed laser was used to irradiate stainless-steel surfaces for generating two-dimensional LIPSS,namely nanodot structures,by cross-scanning the laser beam for a different number of times.The obtained nanodot structures were found to be super hydrophilic just after laser irradiation,but turned to be hydrophobic after exposure in air for a few days.By cross・scanning the laser beam for the same number of times,local LIPSS rewriting was realized.This study showed the possibility of improving the homogeneity of the surface properties of steel materials through laser-induced nanodot structuring.
