In this work,we investigated the influence of air gas pressures on the expansion features of nanosecond laser ablated aluminum plasma in the absence and presence of a nonuniform magnetic field using fast photography.A...In this work,we investigated the influence of air gas pressures on the expansion features of nanosecond laser ablated aluminum plasma in the absence and presence of a nonuniform magnetic field using fast photography.A particular emphasis was given to the plume dynamics（shape,size） with the combined effects of ambient gas pressures and an external magnetic field.Free expansion,sharpening effect,and hemi-spherical structures of the aluminum plasma were observed without a magnetic field under different gas pressures.Analysis of the resulting plume images with the combined effects of air gas pressures and a magnetic field show significant changes,such as plume splitting,elliptical geometry changes,radial expansion,and plume confinement.Furthermore,the total size of the plasma plume with a magnetic field was measured to be smaller than the plasma plume without a magnetic field at several background pressures.展开更多
In this work, we investigated the plasma morphology induced by a Nd：YAG laser with the aim of improving the understanding of the formation and dynamics of the plasma in two cases, with and without a magnetic field. S...In this work, we investigated the plasma morphology induced by a Nd：YAG laser with the aim of improving the understanding of the formation and dynamics of the plasma in two cases, with and without a magnetic field. Single laser pulse production of a plasma in the absence and presence of a magnetic field was performed with an aluminum target in air. A fast photography technique was employed to obtain information about the expansion dynamics and confinement of the aluminum plasma in each case. The generation of the laser plasma was allowed to expand at two locations with different magnetic field strengths, which correspond to the strength 0.58 T in the center of two magnetic poles and 0.83 T at a distance of 4 mm from the upper pole （N）. The plume showed lateral confinement at longer delays when the target was placed at the center of the two poles. When the target was placed at a distance of 4 mm from the upper pole it was observed that the plume was divided into two lobes at the initial stage and traveled towards the center of the magnetic field with further elapse of time.展开更多
基金supported by National Nature Science Foundation of China under Grant Nos.61178022 and 61575030Research funds for the Doctoral program of Higher Education of China(No.20112216120006,20122216120009)supported by the Science and Technology Department of Changchou City(No.14KP007)
文摘In this work,we investigated the influence of air gas pressures on the expansion features of nanosecond laser ablated aluminum plasma in the absence and presence of a nonuniform magnetic field using fast photography.A particular emphasis was given to the plume dynamics（shape,size） with the combined effects of ambient gas pressures and an external magnetic field.Free expansion,sharpening effect,and hemi-spherical structures of the aluminum plasma were observed without a magnetic field under different gas pressures.Analysis of the resulting plume images with the combined effects of air gas pressures and a magnetic field show significant changes,such as plume splitting,elliptical geometry changes,radial expansion,and plume confinement.Furthermore,the total size of the plasma plume with a magnetic field was measured to be smaller than the plasma plume without a magnetic field at several background pressures.
基金supported by National Natural Science Foundation of China(No.61178022)the Research Foundation for Doctoral Program of Higher Education of China(Nos.20112216120006,20122216120009 and 20122216110007)the Project of 14KP007
文摘In this work, we investigated the plasma morphology induced by a Nd：YAG laser with the aim of improving the understanding of the formation and dynamics of the plasma in two cases, with and without a magnetic field. Single laser pulse production of a plasma in the absence and presence of a magnetic field was performed with an aluminum target in air. A fast photography technique was employed to obtain information about the expansion dynamics and confinement of the aluminum plasma in each case. The generation of the laser plasma was allowed to expand at two locations with different magnetic field strengths, which correspond to the strength 0.58 T in the center of two magnetic poles and 0.83 T at a distance of 4 mm from the upper pole （N）. The plume showed lateral confinement at longer delays when the target was placed at the center of the two poles. When the target was placed at a distance of 4 mm from the upper pole it was observed that the plume was divided into two lobes at the initial stage and traveled towards the center of the magnetic field with further elapse of time.
