100TW激光与等离子体相互作用中质子背向发射的能谱测量

Measuring energy spectra of proton generated by 100 TW laser-plasma interaction at rear side of target

用100 TW激光器产生的超短超强激光与5μm薄膜Cu靶的进行打靶实验,测量了靶背法线方向产生质子的角分布和能谱。实验中采用辐射变色膜片HD810测量质子的角分布,用CR39和Thomson磁谱仪结合测量质子能量分布。测量结果表明:质子发射张角为10°左右,质子沿着靶背法线方向发射,在能量为570 keV处出现截断。通过测量质子能量分布验证了超短超强激光等离子体相互作用过程中靶背法线鞘层质子加速机制。

In the experiment of 100 TW laser interacting with 5 μm thick Cu target, CR39 and Thomson spectrum are used to detect the energy spectra of proton and radiochromic HD810 is used to detect the distribution of protons at the normal direction of the target＇s back. The results show that the protons are emitted from the normal direction of target-back and have 570 keV cutoff energy and the jet angle is about 10°. The results of the experiment verify that target normal sheath acceleration of proton in the ultra-short and ultra-intense laser interacts with plasmas.