为了探索飞秒激光与固体靶相互作用中高能离子的产生和加速机制,在超短超强激光装置“SILEX-1”上进行了超强激光与平面薄膜Cu靶的相互作用中高能离子能谱分布的实验研究。实验采用固体核径迹探测器CR39和Thomson离子谱仪相结合的方式,在固体靶背表面法线方向测量了质子和C离子能量分布和产额。实验结果表明,实验观察到了质子和C^4+、C^3+、C^2+和CH离子信号;离子沿着靶背法线方向发射,离子在一定能量处出现截断;质子和C^4+、C^3+、C^2+及C^1+离子的截止能分别是1221和1941keV、1899、624、422keV;随着C离子电荷数增加,产额也随着增加;质子的产额远远高于C离子。经分析,高能离子的产生和加速是多种作用机制共同作用的结果,其中静电场中的靶后鞘层加速(TNSA)机制则占主导地位。
To study the generation and the acceleration mechanisms of high energy ions in the interaction of ultra-short ultra-intense laser with solid targets,high energy ions behavior at the normal direction of the rear surface of the target produced from ulintencity pulse laser irradiated Cu thin film solid targets is explored on SILEX-I laser facility. The solid nuclear detector CR39 and Thomson spectrum are used to detect the energy spectra of protons and carbon ions,and the protons and C4+ ,C3+ ,C2+ ,C1+ ions are osderved. The results show that the ions are emitted from the normal direction of target-back and the ions have a certain cut-off energy; the protons and C4+ , C3+ , C2+ , C1+ ions cut-off energy values are separately 1 221 keV,1 941 keV,1899 keV,624 keV,and 422 keV; the carbon ions beam current is increased with carbon ions charge number;the yield of proton is far higher than carbon ions. High energy ion generation and acceleration are the result of a variety of mechanisms where the electrostatic field TNSA acceleration mechanism is dominant.