干涉法诊断由纳秒激光诱导产生的大气等离子体的电子密度  

Experimental diagnosis of electron density of laser induced air plasma by interferometry

作　　者：张宏超[1] 陆建[1] 倪晓武[1] 

机构地区：[1]南京理工大学应用物理系,南京210094

出　　处：《物理学报》2009年第6期4034-4040,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60578015);教育部高校优秀青年教师奖励计划(批准号:20050288025);江苏省研究生创新培养计划资助的课题~~

摘　　要：通过改进的马赫-曾德尔干涉仪获得了高质量的Nd:YAG激光诱导大气等离子体干涉条纹图.利用快速傅里叶变换(FFT)分析法恢复了干涉图波面,通过Abel逆变换进行密度反演,重建了不同时刻激光等离子体电子密度的三维分布,并得到了激光等离子体膨胀速度与延迟时间的关系.结果显示,纳秒激光诱导大气击穿形成的等离子体具有等离子体通道结构,等离子体膨胀速度的迅速衰减,对等离子体通道的塌陷起到了促进作用,等离子体形状的离心率在大约48ns时达到最大值,然后开始向圆形演变.High quality interference pattern was obtained with a modified Mach-Zehnder interferomenter. An FFT analysis is applied to extracting the phase of the reconstructed interferograms, and then the inverse Abel transformation is used to calculate the three- dimensional electron density distribution. The electron density and the plasma expanding velocity at various delay times were obtained. The results show that the formation of the plasma channel in the early stage of the laser induces air plasma, and the rapid decrease of the plasma expanding velocity accelerates the collapse of the plasma channel. At about 48 nanosecond time, the eccentricity of the plasma shape reaches the maximum value and then evolves to a circular shape.

关 键 词：激光等离子体电子密度 干涉测量 Abel逆变换 

分 类 号：O536[理学—等离子体物理]