Mackinnon A J, Borghesi M, Hatchett S, Key M H, Patel P K, Campbell H, Schiavi A, Snavely R, Wilks S C, Willi O
Lawrence Livermore Laboratory, Livermore, California 94550, USA.
Phys Rev Lett. 2001 Feb 26;86(9):1769-72. doi: 10.1103/PhysRevLett.86.1769.
The influence of the plasma density scale length on the production of MeV protons from thin foil targets irradiated at I lambda(2) = 5 x 10(19) W cm(-2) has been studied. With an unperturbed foil, protons with energy >20 MeV were formed in an exponential energy spectrum with a temperature of 2.5+/-0.3 MeV. When a plasma with a scale length of 100 microm was preformed on the back of the foil, the maximum proton energy was reduced to <5 MeV and the beam was essentially destroyed. The experimental results are consistent with an electrostatic accelerating mechanism that requires an ultrashort scale length at the back of the target.
研究了等离子体密度标长对在(I\lambda^{2}=5\times10^{19}\ W\ cm^{-2})下辐照的薄箔靶产生兆电子伏质子的影响。对于未受扰动的箔靶，能量大于(20)兆电子伏的质子以指数能谱形式形成，温度为(2.5\pm0.3)兆电子伏。当在箔靶背面预先形成标长为(100)微米的等离子体时，质子的最大能量降至小于(5)兆电子伏，并且束流基本被破坏。实验结果与一种需要靶背具有超短标长的静电加速机制相一致。
