超短超强激光与固体靶相互作用中背表面光发射的实验研究

从金属箔背表面测量了超热电子穿越固体靶产生的光发射.光发射积分成像图案呈圆环状，在圆环边缘附近出现局部化明亮光信号确定为光学渡越辐射；光发射光谱在300—500nm之间出现一系列非周期锐利尖峰，在400nm（2ω）附近的尖峰较明显，这个光发射取决于v×B加 热机制产生的超热电子束的微束团引起的相干渡越辐射，(v为电子电度，B为磁场强度)，光 强随靶厚度的增加而减小. 关键词： 超热电子 光发射 光学渡越辐射 v×B加热机制 相干渡越辐射

Experimental study of optical emission from the rear surface in ultrashort ultra-intense laser interaction with solid targets

Optical emission generated by hot electrons passing through solid targets is measured from the rear surface of a metallic foil. The integrated image taken by CC D camera shows that the optical emission forms a ring, on the edge of the ring t here is a bright localized signal, which is the optical transition radiation (OT R). The optical emission spectrum shows a series of sharp nonperiodic peaks bet ween 300—500nm,obviously near 400nm(2ω). The sharp peaks are ascribed to the c oherent transition radiation (CTR) of hot electron-beam microbunching generated by v×B acceleration mechanism. The OTR intensity decreases with the increase of the target thickness.