丝阵负载Z箍缩内爆动力学研究

Research of implosion dynamics for wire array Z pinch

丝阵负载内爆动力学行为基本可以分为以下四个过程1)丝的烧蚀;2)壳层的形成;3)内爆;4)滞止.利用所研制的可见光分幅相机和X射线分幅相机在"强光一号"加速器上对多种型号的丝阵负载Z箍缩内爆动力学行为进行了实验研究,获得了从早期单丝烧蚀到等离子体柱崩毁全过程图像,并对实验结果进行了分析,主要研究成果如下1)发现存在较长时间的丝烧蚀过程,且单丝烧蚀在轴向上并不均匀;实验得到的内爆轨迹与唯像模型计算结果较为一致.2)不论早期的可见光图像还是中后期的软X射线图像都存在明显的阴极发射,内爆后期在阴极附近存在明显滞后的辐射分布.3)理论分析和实验结果都表明烧蚀下来的等离子体在轴上发生碰撞形成先驱等离子体柱,先驱等离子体柱经历了先膨胀后压缩的动力学过程.4)根据冕等离子体角向扩展速度,估算了冕等离子体的温度、电离度.

The implosion dynamics of wire array Z pinch can be divided into four stages（1） wire ablation;（2） formation of plasma shell;（3） implosion;（4） stagnation.Based on the optical-framing camera and the soft X-ray framing camera,lots of experiments on the early stage of wire array Z pinch and imploding dynamics have been carried out.Images of wire array Z pinch from wire ablation to plasma column breakdown were obtained.The main results were as follows（1） There is a long ablation stage,and the wire ablation is not uniform along the axis.The imploding experimental trajectory is consistent with the phenomenological model.（2） The cathode emission is obviously observed in both optical images and X ray images.In the late stage of implosion,there is obvious trailing radiation distribution around the cathode.（3） The precursor plasma column is formed after the collision of the ablating plasma at the axis,which expands at first,then becomes compressed.（4） The temperature and ionization stage of corona plasma were estimated according to its azimuthally expanding velocity.